Science.gov

Sample records for air layer sal

  1. An Experiment to Study Sporadic Atom Layers in the Earth's Mesosphere and Lower Thermosphere (SAL)

    NASA Technical Reports Server (NTRS)

    Kelley, Michael C.

    1999-01-01

    The Sudden Atom Layer (SAL) Rocket was successfully launched in February 1998. All instruments worked well except those supplied by NASA Goddard Space Flight Center. (A dummy weight was launched for the neutral mass spectrometer and the ion version died shortly after lift-off.) A paper has already been published in GRL concerning the dust layer detected by an on board instrument and compared to ground-based observations made at the Arecibo Observatory by Cornell graduate student S. Collins (lidar) and Q. Zhou (radar). Collins presented a comparison of the sodium lidar data and onboard observations with a theoretical model by Plane and Cox at the Fan AGU Meeting. In addition Gelinas and Kelley presented a review paper dealing with the entire SAL instrument complement at the same meeting. An unexpected new explanation for the outer scale of E region plasma irregularities has come out of the data set. We anticipate at least a total of four papers will be published within a year of launch.

  2. Re-Evaluating the Role of the Saharan Air Layer in Atlantic Tropical Cyclogenesis and Evolution

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.

    2010-01-01

    The existence of the Saharan air layer (SAL), a layer of warm, dry, dusty air frequently present over the tropical Atlantic Ocean, has long been appreciated. The nature of its impact on hurricanes remains unclear, however, with some researchers arguing that the SAL amplifies hurricane development and with others arguing that it inhibits it. Most research in recent years has emphasized the potential negative impacts of the SAL, but is this emphasis justified? The potential negative impacts of the SAL include 1) vertical wind shear associated with the African easterly jet; 2) warm air aloft, which increases thermodynamic stability at the base of the SAL; and 3) dry air, which produces cold downdrafts. Multiple NASA satellite data sets and NCEP global analyses are used to characterize the SAL's properties and evolution in relation to tropical cyclones and to evaluate these potential negative influences. The results suggest that the negative influences of the SAL have been significantly over-emphasized, in part because of several false assumptions about the structure and role of the SAL.

  3. Improving Our Understanding of Atlantic Hurricanes Through Knowledge of the Saharan Air Layer: Hope Or Hype?

    NASA Technical Reports Server (NTRS)

    Braun, Scott

    2009-01-01

    The existence of the Saharan air layer (SAL), a layer of warm, dry, dusty air frequently present over the tropical Atlantic Ocean, has long been appreciated. The nature of its impact on hurricanes remains unclear, with some researchers arguing that the SAL amplifies hurricane development and with others arguing that it inhibits it. The potential negative impacts of the SAL include 1) low-level vertical wind shear associated with the African easterly jet; 2) warm air aloft, which increases thermodynamic stability; and 3) dry air, which produces cold downdrafts. Some investigators have assumed the validity of these proposed negative influences and have frequently used them to explain the failure of individual storms to intensify or to explain the relative inactivity of recent hurricane seasons. Multiple NASA satellite data sets and National Centers for Environmental Prediction global analyses are used to characterize the SAL's properties and evolution in relation to developing hurricanes. The results will shows that neither jet--induced vertical wind shear nor warm SAL air (high stability) produce significant negative impacts on Atlantic storms. Dry air appears to be a key mechanism for SAL influence, but the presence of dry SAL air is not always a good indicator of whether a storm will weaken since many examples of intensifying storms surrounded by such dry air can be found. Idealized simulations will be used to evaluate the role of dry air. Finally, two case studies of supposedly "prime examples" of SAL influence will show that the negative influences of the SAL are perhaps too readily ascribed to individual storms that fail to reach their maximum potential intensity.

  4. The Effect of the Saharan Air Layer on the Formation of Hurricane Isabel (2003) Simulated with AIRS Data

    NASA Technical Reports Server (NTRS)

    Wu, iguang; Braun, Scott A.; Qu, John J.

    2006-01-01

    The crucial physics of how the atmosphere really accomplishes the tropical cyclogenesis process is still poorly understood. The presence of the Saharan Air Layer (SAL), an elevated mixed layer of warm and dry air that extends from Africa to the tropical Atlantic and contains a substantial amount of mineral dust, adds more complexity to the tropical cyclogenesis process in the Atlantic basin. The impact of the SAL on tropical cyclogenesis is still uncertain. Karyampudi and Carlson (1988) conclude that a strong SAL can potentially aid tropical cyclone development while Dunion and Velden (2004) argue that the SAL generally inhibits tropical cyclogenesis and intensification. Advancing our understanding of the physical mechanisms of tropical cyclogenesis and the associated roles of the SAL strongly depends on the improvement in the observations over the data-sparse ocean areas. After the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU), and the microwave Humidity Sounder of Brazil (HSB) were launched with the NASA Aqua satellite in 2002, new data products retrieved from the AIRS suite became available for studying the effect of the warm, dry air mass associated with the SAL (referred to as the thermodynamic effect). The vertical profiles of the AIRS retrieved temperature and humidity provide an unprecedented opportunity to examine the thermodynamic effect of the SAL. The observational data can be analyzed and assimilated into numerical models, in which the model thermodynamic state is allowed to relax to the observed state from AIRS data. The objective of this study is to numerically demonstrate that the thermodynamic effect of the SAL on the formation of Hurricane Isabel (2003) can be largely simulated through nudging of the AIRS data.

  5. LASE Observations of Interactions Between African Easterly Waves and the Saharan Air Layer

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Ferrare, Richard; Browell, Edward; Kooi, Susan; Biswas, Mrinal; Krishnamurti, T. N.; Notari, Anthony; Heymsfield, Andrew; Butler, Carolyn; Burton, Sharon; Fenn, Marta; Dunion, Jason

    2010-01-01

    The Lidar Atmospheric Sensing Experiment (LASE) participated in the NASA African Monsoon Multidisciplinary Analyses (NAMMA) field experiment in 2006 that was conducted from Sal, Cape Verde to study the Saharan Air Layer (SAL) and its influence on the African Easterly Waves (AEWs) and Tropical Cyclones (TCs). During NAMMA, LASE collected simultaneous water vapor and aerosol lidar measurements from 14 flights onboard the NASA DC- 8. In this paper we present three examples of the interaction of the SAL and AEWs regarding: moistening of the SAL and transfer of latent heat; injection of dust in an updraft; and influence of dry air intrusion on an AEW. A brief discussion is also given on activities related to the refurbishment of LASE to enhance its operational performance and plans to participate in the next NASA hurricane field experiment in the summer of 2010.

  6. Reevaluating the Role of Saharan Air Layer in Atlantic Tropical Cyclogenesis and Evolution

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.

    2010-01-01

    The existence of the Saharan air layer (SAL), a layer of warm, dry, dusty air that frequently moves westward off of the Saharan desert of Africa and over the tropical Atlantic Ocean, has long been appreciated. As air moves over the desert, it is strongly heated from below, producing a very hot air mass at low levels. Because there is no moisture source over the Sahara, the rise in temperature causes a sharp drop in relative humidity, thus drying the air. In addition, the warm air produces a very strong jet of easterly flow in the middle troposphere called the African easterly jet that is thought to play a critical role in hurricane formation. In recent years, there has been an increased focus on the impact that the SAL has on the formation and evolution of hurricanes in the Atlantic. However, the nature of its impact remains unclear, with some researchers arguing that the SAL amplifies hurricane development and with others arguing that it inhibits it. The argument for positively influencing hurricane development is based upon the fact that the African easterly jet provides an energy source for the waves that eventually form hurricanes and that it leads to rising motion south of the jet that favors the development of deep thunderstorm clouds. The potential negative impacts of the SAL include 1) low-level vertical wind shear associated with the African easterly jet; 2) warm SAL air aloft, which increases thermodynamic stability and suppresses cloud development; and 3) dry air, which produces cold downdrafts in precipitating regions, thereby removing energy needed for storm development. As part of this recent focus on the SAL and hurricanes (which motivated a 2006 NASA field experiment), there has been little emphasis on the SAL s potential positive influences and almost complete emphasis on its possible negative influences, almost to the point of claims that the SAL is the major suppressing influence on hurricanes in the Atlantic. In this study, multiple NASA

  7. LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Saharan Air Layers and Tropical Disturbances

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Ferrare, Richard A.; Browell, Edward V.; Kooi, Susan A.; Dunion, Jason P.; Heymsfield, Gerry; Notari, Anthony; Butler, Carolyn F.; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Chen, Gao; Anderson, Bruce

    2010-01-01

    LASE (Lidar Atmospheric Sensing Experiment) on-board the NASA DC-8 measured high resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern North Atlantic during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment. These measurements were used to study African easterly waves (AEWs), tropical cyclones (TCs), and the Saharan Air Layer(s) (SAL). Interactions between the SAL and tropical air were observed during the early stages of the TC development. These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its impact on AEWs and TCs. Examples of profile measurements of aerosol scattering ratios, aerosol extinction coefficients, aerosol optical thickness, water vapor mixing ratios, RH, and temperature are presented to illustrate their characteristics in SAL, convection, and clear air regions. LASE data suggest that the SAL suppresses low-altitude convection at the convection-SAL interface region. Mid-level convection associated with the AEW and transport are likely responsible for high water vapor content observed in the southern regions of the SAL on August 20, 2008. This interaction is responsible for the transfer of about 7 x 10(exp 15) J latent heat energy within a day to the SAL. Measurements of lidar extinction-to-backscatter ratios in the range 36+/-5 to 45+/-5 are within the range of measurements from other lidar measurements of dust. LASE aerosol extinction and water vapor profiles are validated by comparison with onboard in situ aerosol measurements and GPS dropsonde water vapor soundings, respectively.

  8. The seasonal vertical distribution of the Saharan Air Layer and its modulation by the wind

    NASA Astrophysics Data System (ADS)

    Tsamalis, C.; Chédin, A.; Pelon, J.; Capelle, V.

    2013-11-01

    The Saharan Air Layer (SAL) influences large-scale environment from western Africa to eastern tropical Americas, by carrying large amounts of dust aerosols. However, the vertical distribution of the SAL is not well established due to a lack of systematic measurements away from the continents. This can be overcome by using the observations of the spaceborne lidar CALIOP onboard the satellite CALIPSO. By taking advantage of CALIOP's capability to distinguish dust aerosols from other types of aerosols through depolarization, the seasonal vertical distribution of the SAL is analyzed at 1° horizontal resolution over a period of 5 yr (June 2006-May 2011). This study shows that SAL can be identified all year round displaying a clear seasonal cycle. It occurs higher in altitude and more northern in latitude during summer than during winter, but with similar latitudinal extent near Africa for the four seasons. The south border of the SAL is determined by the Intertropical Convergence Zone (ITCZ), which either prohibits dust layers from penetrating it or reduces significantly the number of dust layers seen within or south of it, as over the eastern tropical Atlantic. Spatially, near Africa, it is found between 5° S and 15° N in winter and 5-30° N in summer. Towards the Americas (50° W), SAL is observed between 5° S and 10° N in winter and 10-25° N in summer. During spring and fall, SAL is found between the position of winter and summer not only spatially but also vertically. In winter, SAL occurs in the altitude range 0-3 km off western Africa, decreasing to 0-2 km close to South America. During summer, SAL is found to be thicker and higher near Africa at 1-5 km, reducing to 0-2 km in the Gulf of Mexico, farther west than during the other seasons. SAL is confined to one layer, of which the mean altitude decreases with westward transport by 13 m deg-1 during winter and 28 m deg-1, after 30° W, during summer. Its mean geometrical thickness decreases by 25 m deg-1 in

  9. Transport of desert dust mixed with North African industrial pollutants in the subtropical Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Rodríguez, S.; Alastuey, A.; Alonso-Pérez, S.; Querol, X.; Cuevas, E.; Abreu-Afonso, J.; Viana, M.; Pérez, N.; Pandolfi, M.; de La Rosa, J.

    2011-07-01

    An analysis of chemical composition data of particulate matter samples (TSP, PM10 and PM2.5) collected from 2002 to 2008 in the North Atlantic free troposphere at the Izaña Global Atmospheric Watch (GAW) observatory (Tenerife, Canary Islands) shows that desert dust is very frequently mixed with particulate pollutants in the Saharan Air Layer (SAL). The study of this data set with Median Concentrations At Receptor (MCAR) plots allowed the identification of the potential source regions of the dust and particulate pollutants. Areas located at the south of the southern slope of the Atlas mountains emerge as the most frequent source of the soil desert dust advected to the northern edge of the SAL in summer. Industrial emissions occurring in Northern Algeria, Eastern Algeria, Tunisia and the Atlantic coast of Morocco appear as the most important source of the nitrate, ammonium and a fraction of sulphate (at least 60 % of the sulphate <10 μm transported from some regions) observed in the SAL. These emissions are mostly linked to crude oil refineries, phosphate-based fertilizer industry and power plants. Although desert dust emissions appear as the most frequent source of the phosphorous observed in the SAL, high P concentrations are observed when the SAL is affected by emissions from open mines of phosphate and phosphate based fertilizer industry. The results also show that a significant fraction of the sulphate (up to 90 % of sulphate <10 μm transported from some regions) observed in the SAL may be influenced by soil emissions of evaporite minerals in well defined regions where dry saline lakes (chotts) are present. These interpretations of the MCAR plots are consistent with the results obtained with the Positive Matrix Factorization (PMF2) receptor modelling. The results of this study show that North African industrial pollutants may be mixed with desert dust and exported to the North Atlantic in the Saharan Air Layer.

  10. Transport of desert dust mixed with North African industrial pollutants in the subtropical Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Rodríguez, S.; Alastuey, A.; Alonso-Pérez, S.; Querol, X.; Cuevas, E.; Abreu-Afonso, J.; Viana, M.; Pandolfi, M.; de La Rosa, J.

    2011-03-01

    The chemical composition of particulate matter samples (TSP, PM10 and PM2.5) collected from 2002 to 2008 in the North Atlantic free troposphere at Izaña Global Atmospheric Watch (GAW) observatory (Tenerife, The Canary Islands) was studied. The analysis of the samples collected in the Saharan Air Layer (SAL) shows that soil desert dust is very frequently mixed with particulate pollutants. An analysis of this data set with Median Concentrations At Receptor (MCAR) plots allowed to identify the potential source regions of the dust and particulate pollutants. Areas located at the south of the Southern slope of Atlas emerge as the most frequent source of the soil desert dust advected to the northern edge of the SAL in summer. Industrial emissions occurring along the Atlantic coast of Morocco, Northern Algeria, Eastern Algeria and Tunisia appear as the most important source of the nitrate, ammonium and a fraction of sulphate (at least a 60% of the sulphate <10 μm transported from some regions) observed in the SAL. These emissions are mostly linked to crude oil refineries, phosphate-based fertilizer industry and power plants. Although desert dust emissions appear as the most frequent source of the phosphorous observed in the SAL, high P concentrations are observed when the SAL is affected by emissions from open mines of phosphate and phosphate based fertilizer industry. The results also show that a significant fraction of the sulphate (up to 90% of sulphate <10 μm transported from some regions) observed in the SAL is linked to soil emissions of evaporite minerals in well defined regions where dry saline lakes (chotts) are present. These interpretations of the MCAR plots are consistent with the results obtained with the Positive Matrix Factorization receptor modelling. The results of this study show that North African industrial pollutants may be mixed with desert dust and exported to the North Atlantic in the Saharan Air Layer.

  11. LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Saharan Air Layers and Tropical Disturbances

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Ferrare, Richard; Browell, Edward; Kooi, Susan; Notari, Anthony; Butler, Carolyn; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Dunion, Jason; Heymsfield, Gerry; Anderson, Bruce

    2008-01-01

    LASE (Lidar Atmospheric Sensing Experiment) onboard the NASA DC-8 was used to measure high resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern Atlantic region during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment, which was conducted from August 15 to September 12, 2006. These measurements were made in conjunction with flights designed to study African Easterly Waves (AEW), Tropical Disturbances (TD), and Saharan Aerosol Layers (SALs) as well as flights performed in clear air and convective regions. As a consequence of their unique radiative properties and dynamics, SAL layers have a significant influence in the development of organized convection associated with TD. Interactions of the SAL with tropical air during early stages of the development of TD were observed. These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its impact on TDs and hurricanes. Seven AEWs were studied and four of these evolved into tropical storms and three did not. Three out of the four tropical storms evolved into hurricanes.

  12. The influence of the SAL and lightning on tropospheric ozone variability over the Northern Tropical Atlantic: Results from Cape Verde during 2010

    NASA Astrophysics Data System (ADS)

    Jenkins, Gregory S.; Robjhon, Miliaritiana L.; Smith, Jonathan W.; Clark, Jonathan; Mendes, Luis

    2012-10-01

    We present results for multiple Saharan Air Layer (SAL) events and their relationship to tropospheric ozone mixing ratios that were observed in the Eastern Atlantic during the summer of 2010 using ozonesondes. In particular, 5 SAL events are sampled during 2010 in Cape Verde indicting a reduction of ozone mixing ratios throughout much of the SAL layer, except near the base of the SAL. In this layer of enhanced ozone mixing ratio, we find increases of 20-30 ppb in some cases between non-SAL and SAL conditions. In addition, ozone concentrations are enhanced above the SAL layer, with trajectories suggesting enhancements by lightning from the middle/upper troposphere with outflow from Africa. Additional aircraft measurements are required to examine the chemical and aerosol distributions from the Marine Boundary Layer (MBL) through the upper troposphere to determine the heterogeneous chemical processes related to reduced ozone mixing ratio, and further quantify elevated ozone mixing ratios at the base of the SAL and above the SAL.

  13. Improving our Understanding of Atlantic Tropical Cyclones through Knowledge of the Saharan Air Layer: Hope or Hype?

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.; Shie, Chung-Lin

    2008-01-01

    The existence of the Saharan air layer (SAL), a layer of warm, dry, dusty air that frequently moves westward off of the Saharan desert of Africa and over the tropical Atlantic Ocean, has long been appreciated. As air moves over the desert, it is strongly heated from below, producing a very hot air mass at low levels. Because there is no moisture source over the Sahara, the rise in temperature causes a sharp drop in relative humidity, thus drying the air. In addition, the warm air produces a very strong jet of easterly flow in the middle troposphere called the African easterly jet that is thought to play a critical role in hurricane formation. In recent years, there has been an increased focus on the impact that the SAL has on the formation and evolution of hurricanes in the Atlantic. However, the nature of its impact remains unclear, with some researchers arguing that the SAL amplifies hurricane development and with others arguing that it inhibits it. The argument for positively influencing hurricane development is based upon the fact that the African easterly jet produces the waves that eventually form hurricanes and that it leads to rising motion south of the jet that favors the development of deep thunderstorm clouds. The potential negative impacts of the SAL include 1) low-level vertical wind shear associated with the African easterly jet; 2) warm SAL air aloft, which increases thermodynamic stability and suppresses cloud development; and 3) dry air, which produces cold downdrafts in precipitating regions, thereby removing energy needed for storm development. As part of this recent focus on the SAL and hurricanes (which motivated a 2006 NASA field experiment), there has been little emphasis on the SAL s potential positive influences and almost complete emphasis on its possible negative influences, almost to the point of claims that the SAL is the major suppressing influence on hurricanes in the Atlantic. Multiple NASA satellite data sets (TRMM, MODIS, and AIRS

  14. Ice nucleating particles in the Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Boose, Yvonne; Sierau, Berko; García, M. Isabel; Rodríguez, Sergio; Alastuey, Andrés; Linke, Claudia; Schnaiter, Martin; Kupiszewski, Piotr; Kanji, Zamin A.; Lohmann, Ulrike

    2016-07-01

    This study aims at quantifying the ice nucleation properties of desert dust in the Saharan Air Layer (SAL), the warm, dry and dust-laden layer that expands from North Africa to the Americas. By measuring close to the dust's emission source, before aging processes during the transatlantic advection potentially modify the dust properties, the study fills a gap between in situ measurements of dust ice nucleating particles (INPs) far away from the Sahara and laboratory studies of ground-collected soil. Two months of online INP concentration measurements are presented, which were part of the two CALIMA campaigns at the Izaña observatory in Tenerife, Spain (2373 m a.s.l.), in the summers of 2013 and 2014. INP concentrations were measured in the deposition and condensation mode at temperatures between 233 and 253 K with the Portable Ice Nucleation Chamber (PINC). Additional aerosol information such as bulk chemical composition, concentration of fluorescent biological particles as well as the particle size distribution was used to investigate observed variations in the INP concentration. The concentration of INPs was found to range between 0.2 std L-1 in the deposition mode and up to 2500 std L-1 in the condensation mode at 240 K. It correlates well with the abundance of aluminum, iron, magnesium and manganese (R: 0.43-0.67) and less with that of calcium, sodium or carbonate. These observations are consistent with earlier results from laboratory studies which showed a higher ice nucleation efficiency of certain feldspar and clay minerals compared to other types of mineral dust. We find that an increase of ammonium sulfate, linked to anthropogenic emissions in upwind distant anthropogenic sources, mixed with the desert dust has a small positive effect on the condensation mode INP per dust mass ratio but no effect on the deposition mode INP. Furthermore, the relative abundance of biological particles was found to be significantly higher in INPs compared to the ambient

  15. The Evolution and Role of the Saharan Air Layer During Hurricane Helene (2006)

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.; Sippel, Jason A.; Shie, Chung-Lin; Boller, Ryan A.

    2013-01-01

    The Saharan air layer (SAL) has received considerable attention in recent years as a potential negative influence on the formation and development of Atlantic tropical cyclones. Observations of substantial Saharan dust in the near environment of Hurricane Helene (2006) during the National Aeronautics and Space Administration (NASA) African Monsoon Multidisciplinary Activities (AMMA) Experiment (NAMMA) field campaign led to suggestions about the suppressing influence of the SAL in this case. In this study, a suite of satellite remote sensing data, global meteorological analyses, and airborne data are used to characterize the evolution of the SAL in the environment of Helene and assess its possible impact on the intensity of the storm. The influence of the SAL on Helene appears to be limited to the earliest stages of development, although the magnitude of that impact is difficult to determine observationally. Saharan dust was observed on the periphery of the storm during the first two days of development after genesis when intensification was slow. Much of the dust was observed to move well westward of the storm thereafter, with little SAL air present during the remainder of the storm's lifetime and with the storm gradually becoming a category-3 strength storm four days later. Dry air observed to wrap around the periphery of Helene was diagnosed to be primarily non-Saharan in origin (the result of subsidence) and appeared to have little impact on storm intensity. The eventual weakening of the storm is suggested to result from an eyewall replacement cycle and substantial reduction of the sea surface temperatures beneath the hurricane as its forward motion decreased.

  16. An Overview of SAL

    NASA Technical Reports Server (NTRS)

    Bensalem, Saddek; Ganesh, Vijay; Lakhnech, Yassine; Munoz, Cesar; Owre, Sam; Ruess, Harald; Rushby, John; Rusu, Vlad; Saiedi, Hassen; Shankar, N.

    2000-01-01

    To become practical for assurance, automated formal methods must be made more scalable, automatic, and cost-effective. Such an increase in scope, scale, automation, and utility can be derived from an emphasis on a systematic separation of concerns during verification. SAL (Symbolic Analysis Laboratory) attempts to address these issues. It is a framework for combining different tools to calculate properties of concurrent systems. The heart of SAL is a language, developed in collaboration with Stanford, Berkeley, and Verimag for specifying concurrent systems in a compositional way. Our instantiation of the SAL framework augments PVS with tools for abstraction, invariant generation, program analysis (such as slicing), theorem proving, and model checking to separate concerns as well as calculate properties (i.e., perform, symbolic analysis) of concurrent systems. We. describe the motivation, the language, the tools, their integration in SAL/PAS, and some preliminary experience of their use.

  17. SalSA status

    NASA Astrophysics Data System (ADS)

    Connolly, Amy; SalSA Collaboration

    2009-06-01

    I review the status of SalSA, a proposed antenna array in a large volume salt formation for detecting ultra-high energy neutrinos. We report on measurements taken in 2007 of attenuation lengths in the 125-900 MHz frequency range at the Cote Blanche salt mine near New Iberia, Louisiana, which is the most precise in situ measurement of attenuation lengths in salt to date. We comment on the impact of these measurements on the feasibility of SalSA.

  18. Soluble iron dust export in the high altitude Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Ravelo-Pérez, L. M.; Rodríguez, S.; Galindo, L.; García, M. I.; Alastuey, A.; López-Solano, J.

    2016-05-01

    Every summer huge amounts of desert dust particles are exported from the hyperarid subtropical Sahara to the North Atlantic the so-called Saharan Air Layer (SAL), a dry, warm and dust-laden corridor that expands from the North African coast (1-5 km.a.s.l.) to the Americas above the marine boundary layer. Because of the potential impact of the dust deposited on the ocean on marine biogeochemistry and climate, we studied the Fe solubility (in seawater) of atmospheric aerosols samples directly collected in the SAL off the North African coast, i.e. the fresh aerosols recently exported from the Sahara in the SAL. The aerosol sampling was performed at ˜2400 m.a.s.l. in Izaña observatory in Tenerife island. In the total aerosols, we found low Fe concentrations and high fractional Fe solubility (FFS ˜2%) in the North Atlantic free troposphere airflows and high Fe concentrations and low FFS (˜0.7%) within the SAL; the resulting FFS versus total dust (or total Fe) plot shows a hyperbolic trend attributed to the conservative mixing of 'fine combustion aerosols' and 'lithogenic mineral dust'. We then focused on the soluble Fe in the SAL. Our results indicate that ˜70% of soluble Fe is associated with the dissolution of submicron dust particles, probably involving Fe-bearing clays. We found a FFS of submicron dust (˜6%) higher than that typically observed in submicron particles of soil dust samples (<1%). The correlation between FFS and the ammonium-sulphate/dust ratio and the low variability in the Fe/Al ratio in the dust samples, suggests that the increase in the FFS of submicron dust aerosols (with respect to soil dust particles) may be related to the presence of acid pollutants mixed with dust. Previous studies had focused on dust processing and changes of Fe solubility during the trans-Atlantic transport of dust in the SAL. We found that submicron dust exported off the coast of North Africa may have already experienced acid processing over the Sahara, i.e. before

  19. Principle Component Analysis of the Evolution of the Saharan Air Layer and Dust Transport: Comparisons between a Model Simulation and MODIS Retrievals

    NASA Technical Reports Server (NTRS)

    Wong, S.; Colarco, P. R.; Dessler, A.

    2006-01-01

    The onset and evolution of Saharan Air Layer (SAL) episodes during June-September 2002 are diagnosed by applying principal component analysis to the NCEP reanalysis temperature anomalies at 850 hPa, where the largest SAL-induced temperature anomalies are located. The first principal component (PC) represents the onset of SAL episodes, which are associated with large warm anomalies located at the west coast of Africa. The second PC represents two opposite phases of the evolution of the SAL. The positive phase of the second PC corresponds to the southwestward extension of the warm anomalies into the tropical-subtropical North Atlantic Ocean, and the negative phase corresponds to the northwestward extension into the subtropical to mid-latitude North Atlantic Ocean and the southwest Europe. A dust transport model (CARMA) and the MODIS retrievals are used to study the associated effects on dust distribution and deposition. The positive (negative) phase of the second PC corresponds to a strengthening (weakening) of the offshore flows in the lower troposphere around 10deg - 20degN, causing more (less) dust being transported along the tropical to subtropical North Atlantic Ocean. The variation of the offshore flow indicates that the subseasonal variation of African Easterly Jet is associated with the evolution of the SAL. Significant correlation is found between the second PC time series and the daily West African monsoon index, implying a dynamical linkage between West African monsoon and the evolution of the SAL and Saharan dust transport.

  20. Particle settling and vertical mixing in the Saharan Air Layer as seen from an integrated model, lidar, and in situ perspective

    NASA Astrophysics Data System (ADS)

    Gasteiger, Josef; Groß, Silke; Sauer, Daniel; Haarig, Moritz; Ansmann, Albert; Weinzierl, Bernadett

    2017-01-01

    Long-range transport of aerosol in the Saharan Air Layer (SAL) across the Atlantic plays an important role for weather, climate, and ocean fertilization. However, processes occurring within the SAL and their effects on aerosol properties are still unclear. In this work we study particle settling and vertical mixing within the SAL based on measured and modeled vertical aerosol profiles in the upper 1 km of the transported SAL. We use ground-based lidar measurements and airborne particle counter measurements over the western Atlantic, collected during the SALTRACE campaign, as well as space-based CALIOP lidar measurements from Africa to the western Atlantic in the summer season. In our model we take account of the optical properties and the Stokes gravitational settling of irregularly shaped Saharan dust particles.We test two hypotheses about the occurrence of vertical mixing within the SAL over the Atlantic to explain the aerosol profiles observed by the lidars and the particle counter. Our first hypothesis (H1) assumes that no mixing occurs in the SAL leading to a settling-induced separation of particle sizes. The second hypothesis (H2) assumes that vertical mixing occurs in the SAL allowing large super-micron dust particles to stay airborne longer than without mixing. The uncertainties of the particle linear depolarization ratio (δl) profiles measured by the ground-based lidars are comparable to the modeled differences between H1 and H2 and do not allow us to conclude which hypothesis fits better. The SALTRACE in situ data on size-resolved particle number concentrations show a presence of large particles near the SAL top that is inconsistent with H1. The analysis of the CALIOP measurements also reveals that the average δl profile over the western Atlantic is inconsistent with H1. Furthermore, it was found that the average δl profile in the upper 1 km of the SAL does not change along its transport path over the Atlantic. These findings give evidence that

  1. Dynamic air layer on textured superhydrophobic surfaces.

    PubMed

    Vakarelski, Ivan U; Chan, Derek Y C; Marston, Jeremy O; Thoroddsen, Sigurdur T

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model.

  2. Satellite Sounder Observations of Contrasting Tropospheric Moisture Transport Regimes: Saharan Air Layers, Hadley Cells, and Atmospheric Rivers

    SciTech Connect

    Nalli, Nicholas R.; Barnet, Christopher D.; Reale, Tony; Liu, Quanhua; Morris, Vernon R.; Spackman, J. Ryan; Joseph, Everette; Tan, Changyi; Sun, Bomin; Tilley, Frank; Leung, L. Ruby; Wolfe, Daniel

    2016-12-01

    This paper examines the performance of satellite sounder atmospheric vertical moisture proles (AVMP) under tropospheric conditions encompassing moisture contrasts driven by convection and advection transport mechanisms, specifically Atlantic Ocean Saharan air layers (SALs) and Pacific Ocean moisture conveyer belts (MCBs) commonly referred to as atmospheric rivers (ARs), both of these being mesoscale to synoptic meteorological phenomena within the vicinity of subtropical Hadley subsidence zones. Operational AVMP environmental data records retrieved from the Suomi National Polar-orbiting Partnership (SNPP) NOAA-Unique Combined Atmospheric Processing System (NUCAPS) are collocated with dedicated radiosonde observations (RAOBs) obtained from ocean-based intensive field campaigns; these RAOBs provide uniquely independent correlative truth data not assimilated into numerical weather prediction models for satellite sounder validation over open ocean. Using these marine-based data, we empirically assess the performance of the operational NUCAPS AVMP product for detecting and resolving these tropospheric moisture features over otherwise RAOB-sparse regions.

  3. Leaping shampoo glides on a lubricating air layer

    NASA Astrophysics Data System (ADS)

    Lee, S.; Li, E. Q.; Marston, J. O.; Bonito, A.; Thoroddsen, S. T.

    2013-06-01

    When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer. We identify this layer by looking through the pool liquid and observing its rupture into fine bubbles. The resulting microbubble sizes suggest this air layer is of submicron thickness. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding.

  4. Leaping shampoo glides on a lubricating air layer.

    PubMed

    Lee, S; Li, E Q; Marston, J O; Bonito, A; Thoroddsen, S T

    2013-06-01

    When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer. We identify this layer by looking through the pool liquid and observing its rupture into fine bubbles. The resulting microbubble sizes suggest this air layer is of submicron thickness. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding.

  5. Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

    NASA Astrophysics Data System (ADS)

    Katunská, Jana; Bullová, Iveta; Špaková, Miroslava

    2016-12-01

    The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

  6. Mixing layer height and air pollution levels in urban area

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Wagner, Patrick; Emeis, Stefan; Jahn, Carsten; Muenkel, Christoph; Suppan, Peter

    2012-10-01

    Ceilometers are applied by KIT/IMK-IFU to detect layering of the lower atmosphere continuously. This is necessary because not only wind speed and direction but also atmospheric layering and especially the mixing layer height (MLH) influence exchange processes of ground level emissions. It will be discussed how the ceilometer monitoring information is used to interpret the air pollution near the ground. The information about atmospheric layering is continuously monitored by uninterrupted remote sensing measurements with the Vaisala ceilometer CL51 which is an eye-safe commercial mini-lidar system. Special software for this ceilometer provides routine retrievals of lower atmosphere layering from vertical profiles of laser backscatter data. An intensive measurement period during the winter 2011/2012 is studied. The meteorological influences upon air pollutant concentrations are investgated and the correlations of air pollutant concentrations with ceilometer MLH are determined. Benzene was detected by department of Applied Climatology and Landscape Ecology, University of Duisburg-Essen (UDE) with a gas chromatograph during the measurement period. The meteorological data are collected by UDE and the monitoring station Essen of the German national meteorological service DWD. The concentrations of the air pollutants NO, NO2 and PM10 are provided by the national air pollution network LANUV.

  7. Nonmethane hydrocarbons in Southern Ocean boundary layer air

    NASA Astrophysics Data System (ADS)

    Lewis, Alastair C.; Carpenter, Lucy J.; Pilling, Michael J.

    2001-03-01

    Measurements at the remote marine boundary layer station of Cape Grim, Northwest Tasmania, allow study of the unperturbed background atmosphere. Here we present a continuous data series of nonmethane hydrocarbons (NMHCs), measured in situ and with high sensitivity during the Second Southern Ocean Photochemistry Experiment (SOAPEX 2) during austral summer 1999. Air masses arriving at Cape Grim originate from the Australian continent, Tasmania, and Southern Ocean and Antarctic regions. In Southern Ocean marine boundary layer (MBL) air, C2 and C3 alkanes show a highly uniform abundance (ethane 142±11.9 parts per trillion by volume (pptv), propane 8.9±1.7 pptv) at around 4 times lower concentrations than encountered in unpolluted Northern Hemisphere MBL air. The presence of shorter-lived NMHCs in marine air indicates sources of both C4-C6 alkanes and several alkenes in the Southern Ocean. The alkane isomer distributions and abundances are in broad agreement with literature sea-air flux rates. In dynamically stable maritime air, midday maxima in ethene, propene, and isoprene concentrations of a few pptv indicate photochemically driven sources very near to the sea surface. Despite their high reactivity, the impact of these oceanic alkenes on local OH concentrations in remote MBL air is not significant. However, the abundance of isoprene in marine air may significantly elevate formaldehyde above that generated by methane oxidation.

  8. The footprints of Saharan air layer and lightning on the formation of tropical depressions over the eastern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Centeno Delgado, Diana C.; Chiao, Sen

    2014-09-01

    The roles of the Saharan Air Layer (SAL) and lightning during genesis of Tropical Depression (TD) 8 (2006) and TD 12 (2010) were investigated in relation to the interaction of the dust outbreaks with each system and their surrounding environment. This study applied data collected from the 2006 NASA African Monsoon Multidisciplinary Analysis and 2010 Genesis and Rapid Intensification Processes projects. Satellite observations from METEOSAT and Moderate Resolution Imaging Spectroradiometer (MODIS)—Aerosol Optical Depth (AOD) were also employed for the study of the dust content. Lightning activity data from the Met Office Arrival Time Difference (ATD) system were used as another parameter to correlate moist convective overturning and a sign of cyclone formation. The AOD and lightning analysis for TD 8 demonstrated the time-lag connection through their positive contribution to TC-genesis. TD 12 developed without strong dust outbreak, but with lower wind shear (2 m s-1) and an organized Mesoscale Convective System (MCS). Overall, the results from the combination of various data analyses in this study support the fact that both systems developed under either strong or weak dust conditions. From these two cases, the location (i.e., the target area) of strong versus weak dust outbreaks, in association with lightning, were essential interactions that impacted TC-genesis. While our dust footprints hypothesis applied under strong dust conditions (i.e., TD 8), other factors (e.g., vertical wind shear, pre-existing vortex and trough location, thermodynamics) need to be evaluated as well. The results from this study suggest that the SAL is not a determining factor that affects the formation of tropical cyclones (i.e., TD 8 and TD 12).

  9. The footprints of Saharan air layer and lightning on the formation of tropical depressions over the eastern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Centeno Delgado, Diana C.; Chiao, Sen

    2015-02-01

    The roles of the Saharan Air Layer (SAL) and lightning during genesis of Tropical Depression (TD) 8 (2006) and TD 12 (2010) were investigated in relation to the interaction of the dust outbreaks with each system and their surrounding environment. This study applied data collected from the 2006 NASA African Monsoon Multidisciplinary Analysis and 2010 Genesis and Rapid Intensification Processes projects. Satellite observations from METEOSAT and Moderate Resolution Imaging Spectroradiometer (MODIS)—Aerosol Optical Depth (AOD) were also employed for the study of the dust content. Lightning activity data from the Met Office Arrival Time Difference (ATD) system were used as another parameter to correlate moist convective overturning and a sign of cyclone formation. The AOD and lightning analysis for TD 8 demonstrated the time-lag connection through their positive contribution to TC-genesis. TD 12 developed without strong dust outbreak, but with lower wind shear (2 m s-1) and an organized Mesoscale Convective System (MCS). Overall, the results from the combination of various data analyses in this study support the fact that both systems developed under either strong or weak dust conditions. From these two cases, the location (i.e., the target area) of strong versus weak dust outbreaks, in association with lightning, were essential interactions that impacted TC-genesis. While our dust footprints hypothesis applied under strong dust conditions (i.e., TD 8), other factors (e.g., vertical wind shear, pre-existing vortex and trough location, thermodynamics) need to be evaluated as well. The results from this study suggest that the SAL is not a determining factor that affects the formation of tropical cyclones (i.e., TD 8 and TD 12).

  10. The footprints of Saharan Air Layer and lightning on the formation of tropical depressions over the eastern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Centeno Delgado, Diana C.

    In this study, the results of an observational analysis and a numerical analysis on the role of the Saharan Air Layer during tropical cyclogenesis (TC-genesis) are described. The observational analysis investigates the interaction of dust particles and lightning during the genesis stage of two developed cases (Hurricanes Helene 2006 and Julia 2010). The Weather Research and Forecasting (WRF) and WRF-Chemistry models were used to include and monitor the aerosols and chemical processes that affect TC-genesis. The numerical modeling involved two developed cases (Hurricanes Helene 2006 and Julia 2010) and two non-developed cases (Non-Developed 2011 and Non-Developed 2012). The Aerosol Optical Depth (AOD) and lightning analysis for Hurricane Helene 2006 demonstrated the time-lag connection through their positive contribution to TC-genesis. The observational analyses supported the fact that both systems developed under either strong or weak dust conditions. From the two cases, the location of strong versus weak dust outbreaks in association with lightning was essential interactions that impacted TC-genesis. Furthermore, including dust particles, chemical processes, and aerosol feedback in the simulations with WRF-CHEM provides results closer to observations than regular WRF. The model advantageously shows the location of the dust particles inside of the tropical system. Overall, the results from this study suggest that the SAL is not a determining factor that affects the formation of tropical cyclones.

  11. Air motion determination by tracking humidity patterns in isentropic layers

    NASA Technical Reports Server (NTRS)

    Mancuso, R. L.; Hall, D. J.

    1975-01-01

    Determining air motions by tracking humidity patterns in isentropic layers was investigated. Upper-air rawinsonde data from the NSSL network and from the AVE-II pilot experiment were used to simulate temperature and humidity profile data that will eventually be available from geosynchronous satellites. Polynomial surfaces that move with time were fitted to the mixing-ratio values of the different isentropic layers. The velocity components of the polynomial surfaces are part of the coefficients that are determined in order to give an optimum fitting of the data. In the mid-troposphere, the derived humidity motions were in good agreement with the winds measured by rawinsondes so long as there were few or no clouds and the lapse rate was relatively stable. In the lower troposphere, the humidity motions were unreliable primarily because of nonadiabatic processes and unstable lapse rates. In the upper troposphere, the humidity amounts were too low to be measured with sufficient accuracy to give reliable results. However, it appears that humidity motions could be used to provide mid-tropospheric wind data over large regions of the globe.

  12. Ignition of hydrogen/air mixing layer in turbulent flows

    SciTech Connect

    Im, H.G.; Chen, J.H.; Law, C.K.

    1998-03-01

    Autoignition of a scalar hydrogen/air mixing layer in homogeneous turbulence is studied using direct numerical simulation. An initial counterflow of unmixed nitrogen-diluted hydrogen and heated air is perturbed by two-dimensional homogeneous turbulence. The temperature of the heated air stream is chosen to be 1,100 K which is substantially higher than the crossover temperature at which the rates of the chain branching and termination reactions become equal. Three different turbulence intensities are tested in order to assess the effect of the characteristic flow time on the ignition delay. For each condition, a simulation without heat release is also performed. The ignition delay determined with and without heat release is shown to be almost identical up to the point of ignition for all of the turbulence intensities tested, and the predicted ignition delays agree well within a consistent error band. It is also observed that the ignition kernel always occurs where hydrogen is focused, and the peak concentration of HO{sub 2} is aligned well with the scalar dissipation rate. The dependence of the ignition delay on turbulence intensity is found to be nonmonotonic. For weak to moderate turbulence the ignition is facilitated by turbulence via enhanced mixing, while for stronger turbulence, whose timescale is substantially smaller than the ignition delay, the ignition is retarded due to excessive scalar dissipation, and hence diffusive loss, at the ignition location. However, for the wide range of initial turbulence fields studied, the variation in ignition delay due to the corresponding variation in turbulence intensity appears to be quite small.

  13. Evaluation of air permeability in layered unsaturated materials.

    PubMed

    Switzer, Christine; Kosson, David S

    2007-03-20

    Field estimation of air permeability is important in the design and operation of soil-vapor extraction systems. Previous models have examined airflow in homogenous soils, incorporating leakage through a low-permeability cap either as a correction to the airflow equation or as a boundary condition. The dual leakage model solution developed here improves upon the previous efforts by adding a leaky lower boundary condition, allowing for the examination of airflow in heterogeneous layered soils. The dual leakage model is applied to the evaluation of pump tests at a pilot soil-vapor extraction system at the Savannah River Site in South Carolina. A thick, low-permeability, stiff clay layer divides the stratigraphy at the site into two units for evaluation. A modified version of the previous model, using the water table as the impermeable lower boundary, is used to evaluate the permeability of the low-permeability stiff clay layer (3.2 x 10(-10) cm(2)) and permeable sand (7.2 x 10(-7) cm(2)) beneath it. The stiff clay permeability estimate is used in the evaluation of the shallow unit. Permeability estimates of the shallow sand (3.8 x 10(-7) cm(2)) and kaolin cap (1.5 x 10(-9)cm(2)) were obtained with the dual leakage model. The shallow unit was evaluated using the previous model for comparison. The effects of anisotropy were investigated with a series of model simulations based on the shallow unit solution. The anisotropy sensitivity analysis suggests that increased anisotropy ratio or decreased axial permeability has a significant impact on the velocity profile at the lower boundary, especially at high values of the anisotropy ratio. This result may increase estimates of SVE removal rates for contaminants located at the interface of the lower boundary, typical of chlorinated solvent contamination.

  14. Direct Numerical Simulation of Air Layer Drag Reduction over a Backward-facing Step

    NASA Astrophysics Data System (ADS)

    Kim, Dokyun; Moin, Parviz

    2010-11-01

    Direct Numerical Simulation (DNS) of two-phase flow is performed to investigate the air layer drag reduction (ALDR) phenomenon in turbulent flow over a backward-facing step. In their experimental study, Elbing et al. (JFM, 2008) have observed a stable air layer on an entire flat plate if air is injected beyond the critical air-flow rate. In the present study, air is injected at the step on the wall into turbulent water flow for ALDR. The Reynolds and Weber numbers based on the water properties and step height are 22,800 and 560, respectively. An inlet section length before the step is 3h and the post expansion length is 30h, where h is the step height. The total number of grid points is about 271 million for DNS. The level set method is used to track the phase interface and the structured-mesh finite volume solver is used with an efficient algorithm for two-phase DNS. Two cases with different air-flow rates are performed to investigate the mechanism and stability of air layer. For high air-flow rate, the stable air layer is formed on the plate and more than 90% drag reduction is obtained. In the case of low air-flow rate, the air layer breaks up and ALDR is not achieved. The parameters governing the stability of air layer from the numerical simulations is also consistent with the results of stability analysis.

  15. The Status of SalSA Detector

    NASA Astrophysics Data System (ADS)

    Milincic, Radovan

    2007-08-01

    We report on the current status of the Salt dome Shower Array (SalSA) ultra high energy neutrino detector. The astrophysics and particle physics prospects with SalSA detector are discussed as well as result of the calibration measurements of the shower development from ultra high energy particle interaction in rock salt. The 10 km3 water equivalent volume detector provides opportunity to advance measurements from mere detection to actual exploration and characterization of the high energy particles in the energy range above 1017 eV. Our MC simulations show that expected number of GZK neutrino events ranges between 10 and 200 depending on the theoretical models. The angular resolution provides us with the posibility of exploring different scenarios of large extra dimensions. The detector capability to distinguish between different neutrino flavors will result in study of neutrino oscillations in the extreme energy range and with largest L/E ratio.

  16. Modeling and Analysis of Asynchronous Systems Using SAL and Hybrid SAL

    NASA Technical Reports Server (NTRS)

    Tiwari, Ashish; Dutertre, Bruno

    2013-01-01

    We present formal models and results of formal analysis of two different asynchronous systems. We first examine a mid-value select module that merges the signals coming from three different sensors that are each asynchronously sampling the same input signal. We then consider the phase locking protocol proposed by Daly, Hopkins, and McKenna. This protocol is designed to keep a set of non-faulty (asynchronous) clocks phase locked even in the presence of Byzantine-faulty clocks on the network. All models and verifications have been developed using the SAL model checking tools and the Hybrid SAL abstractor.

  17. Multi-layered, chemically bonded lithium-ion and lithium/air batteries

    DOEpatents

    Narula, Chaitanya Kumar; Nanda, Jagjit; Bischoff, Brian L; Bhave, Ramesh R

    2014-05-13

    Disclosed are multilayer, porous, thin-layered lithium-ion batteries that include an inorganic separator as a thin layer that is chemically bonded to surfaces of positive and negative electrode layers. Thus, in such disclosed lithium-ion batteries, the electrodes and separator are made to form non-discrete (i.e., integral) thin layers. Also disclosed are methods of fabricating integrally connected, thin, multilayer lithium batteries including lithium-ion and lithium/air batteries.

  18. Atmospheric Boundary Layer Modeling for Combined Meteorology and Air Quality Systems

    EPA Science Inventory

    Atmospheric Eulerian grid models for mesoscale and larger applications require sub-grid models for turbulent vertical exchange processes, particularly within the Planetary Boundary Layer (PSL). In combined meteorology and air quality modeling systems consistent PSL modeling of wi...

  19. Determination of mixing layer heights by ceilometer and influences upon air quality at Mexico City airport

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Flores-Jardines, Edgar; Emeis, Stefan; Grutter, Michel; Kurtenbach, Ralf; Wiesen, Peter; Münkel, Christoph

    2009-09-01

    Monitoring of mixing layer height (MLH) was performed during different measurement campaigns in urban and suburban area (Hannover, Munich, Budapest, Zürich, Augsburg) by the Vaisala ceilometer LD40. It is an eye-safe commercial lidar and designed originally to detect cloud base heights and vertical visibility for aviation safety purposes. Software for routine retrieval of mixing layer height from ceilometer data was developed and improved continuously. MLH was determined during a one-week-campaign at the airport Mexico City. Air pollutants like NO, NOx, CO and O3 as well as meteorological parameters like wind, temperature and irradiance are measured at the airport in addition to the air quality monitoring network RAMA in Mexico City. The influence of MLH together with wind, temperature and cloudiness upon air pollution is investigated. These continuous MLH and meteorological data are correlated with simultaneous measured air pollutants. The influence of mixing layer height upon air quality is shown.

  20. Turbulent Boundary Layer in High Rayleigh Number Convection in Air

    NASA Astrophysics Data System (ADS)

    du Puits, Ronald; Li, Ling; Resagk, Christian; Thess, André; Willert, Christian

    2014-03-01

    Flow visualizations and particle image velocimetry measurements in the boundary layer of a Rayleigh-Bénard experiment are presented for the Rayleigh number Ra =1.4×1010. Our visualizations indicate that the appearance of the flow structures is similar to ordinary (isothermal) turbulent boundary layers. Our particle image velocimetry measurements show that vorticity with both positive and negative sign is generated and that the smallest flow structures are 1 order of magnitude smaller than the boundary layer thickness. Additional local measurements using laser Doppler velocimetry yield turbulence intensities up to I=0.4 as in turbulent atmospheric boundary layers. From our observations, we conclude that the convective boundary layer becomes turbulent locally and temporarily although its Reynolds number Re ≈200 is considerably smaller than the value 420 underlying existing phenomenological theories. We think that, in turbulent Rayleigh-Bénard convection, the transition of the boundary layer towards turbulence depends on subtle details of the flow field and is therefore not universal.

  1. Mixing layer growth and background air-quality measurements over the Colorado oil-shale area

    SciTech Connect

    Laulainen, N.S.; Whiteman, C.D.; Davis, W.E.; Thorp, J.M.

    1981-06-01

    The daily growth of convective boundary layers over the complex terrain of the oil shale areas of Colorado is a prominent feature of the meteorology of the region. The development of these layers was investigated using airsondes, rawinsondes, and aircraft. The deep growth of the layers in August, to heights in excess of 5500-m MSL on clear or partly cloudy days, is expected to have important implications for the dispersal of pollutants released in the region as the oil shale resource undergoes future development. Aircraft observations show that the present background air quality is good over the region and that pollutants, when present, become well mixed throughout the depth of the convective boundary layer. The layer therefore represents an important natural means of dilution for pollutants introduced into the atmosphere. Work is proceeding to incorporate the time-dependent convective boundary layer growth into air pollution models for the region.

  2. The relationship between air layers and evaporative resistance of male Chinese ethnic clothing.

    PubMed

    Wang, Faming; Peng, Hui; Shi, Wen

    2016-09-01

    In this study, the air layer distribution and evaporative resistances of 39 sets of male Chinese ethnic clothing were investigated using a sweating thermal manikin and the three-dimensional (3D) body scanning technique. Relationships between the evaporative resistance and air layers (i.e., air gap thickness and air volume) were explored. The results demonstrated that the clothing total evaporative resistance increases with the increasing air gap size/air volume, but the rate of increase gradually decreases as the mean air gap size or the total air volume becomes larger. The clothing total evaporative resistance reaches its maximum when the average air gap size and the total air volume are 41.6 mm and 69.9 dm(3), respectively. Similar general trends were also found between local mean air gap size and clothing local evaporative resistance at different body parts. However, different body parts show varied rates of increase and decrease in the local evaporative resistance. The research findings provide a comprehensive database for predicting overall and local human thermal comfort while wearing male Chinese ethnic clothing.

  3. Dynamic of Air Invasion in an Immersed Granular Layer

    NASA Astrophysics Data System (ADS)

    Varas, G.; Ramos, G.; Géminard, J. C.; Vidal, V.

    2014-12-01

    Displacement processes (typically, grains displaced by a fluid) are the driving mechanism which control the dynamics of many geological processes (e.g. oil extraction, air sparging, piercement structures). They also play an important role in a wide range of industrial applications, from ground water hydrology and soil mechanics to agricultural engineering. The interaction between one or more moving fluids (e.g. rising gas immersed in a granular medium) and grains control the dynamics of these phenomena. Due to their economic and ecological importance, it is essential to understand the variety and potentiality of these phenomena. When an ascending air passes trough an immersed granular bed its fluidized producing the grains to start to move. When this process is repeated, its created a fluidized zone that evolves over time. Here, we investigate the morphology and dynamics of the region invaded by air as a function of a dimensionless parameter χ which accounts for the relative effects of the gravity and the capillarity. We propose new experimental observations on the air invasion regimes and on the morphology of the fluidized zone, in particular its growth dynamics.

  4. Novel Approach for Modeling of Nonuniform Slag Layers and Air Gap in Continuous Casting Mold

    NASA Astrophysics Data System (ADS)

    Wang, Xudong; Kong, Lingwei; Yao, Man; Zhang, Xiaobing

    2017-02-01

    Various kinds of surface defects on the continuous casting slab usually originate from nonuniform heat transfer and mechanical behavior, especially during the initial solidification inside the mold. In this article, a model-coupled inverse heat transfer problem incorporating the effect of slag layers and air gap is developed to study the nonuniform distribution of liquid slag, solid slag, and air gap layers. The model considers not only the formation and evolution of slag layers and air gap but also the temperatures in the mold copper as measured by thermocouples. The simulation results from the model and the measured temperatures from experiments are shown to be in good agreement with each other. At the casting speed of 0.65 m/min, the liquid slag film disappears and transforms into solid slag entirely at about 400 mm away from meniscus, and an air gap begins to form. Until the mold exit, the maximum thickness of the solid slag layer and air gap gradually increases to 1.34 and 0.056 mm, respectively. The results illustrate that the magnitude and nonuniform distribution of the slag layers and air gap along the cross direction, correlating with heat flux between the shell and mold, eventually determine the temperature profiles of the mold hot face and slab surface. The proposed model may provide a convenient approach for analyzing nonuniform heat transfer and mechanical behaviors between the mold and slab in the real casting process.

  5. Leaping shampoo glides on a 500-nm-thick lubricating air layer

    NASA Astrophysics Data System (ADS)

    Li, Erqiang; Lee, Sanghyun; Marston, Jeremy; Bonito, Andrea; Thoroddsen, Sigurdur

    2013-11-01

    When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer [Lee et al., Phys. Rev. E 87, 061001 (2013)]. We identify this layer by looking through the pool liquid and observing its rupture into fine micro-bubbles. The resulting micro-bubble sizes suggest that the thickness of this air layer is around 500 nm. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding, with the shear stress within the thin air layer sufficient for the observed deceleration. Particle tracking within the jet shows uniform velocity, with no pronounced shear, which would be required for shear-thinning effects. The role of the surfactant may primarily be to stabilize the air film.

  6. A numerical study of air layer drag reduction phenomenon on a flat plate

    NASA Astrophysics Data System (ADS)

    Kim, Dokyun; Moin, Parviz

    2009-11-01

    The objective of the present study is to predict and understand the air layer drag reduction (ALDR) phenomenon. Recent experiments (Elbing et al. JFM 2008) have shown large net drag reductions if air is injected beyond a critical rate at the wall. The stability analysis and numerical simulations are performed to investigate mechanisms of ALDR on a flat plate using the same geometry as in the experiment. The linear stability of air-liquid interface is investigated by solving the Orr-Sommerfeld equations, and numerical simulations of two-phase flow have been performed to describe the evolution of air-water interface. The stability analysis shows that the air flow rates, Reynolds number, Weber number, and Froude number are important parameters determining the stability of the air layer. In laminar boundary layer, it is observed from the numerical simulations that the Froude number is the key to the stability of the air layer. The presentation will include a new and very efficient numerical method for two-phase flow calculations used in this study.

  7. Uncertainty Analysis of Air Radiation for Lunar Return Shock Layers

    NASA Technical Reports Server (NTRS)

    Kleb, Bil; Johnston, Christopher O.

    2008-01-01

    By leveraging a new uncertainty markup technique, two risk analysis methods are used to compute the uncertainty of lunar-return shock layer radiation predicted by the High temperature Aerothermodynamic Radiation Algorithm (HARA). The effects of epistemic uncertainty, or uncertainty due to a lack of knowledge, is considered for the following modeling parameters: atomic line oscillator strengths, atomic line Stark broadening widths, atomic photoionization cross sections, negative ion photodetachment cross sections, molecular bands oscillator strengths, and electron impact excitation rates. First, a simplified shock layer problem consisting of two constant-property equilibrium layers is considered. The results of this simplified problem show that the atomic nitrogen oscillator strengths and Stark broadening widths in both the vacuum ultraviolet and infrared spectral regions, along with the negative ion continuum, are the dominant uncertainty contributors. Next, three variable property stagnation-line shock layer cases are analyzed: a typical lunar return case and two Fire II cases. For the near-equilibrium lunar return and Fire 1643-second cases, the resulting uncertainties are very similar to the simplified case. Conversely, the relatively nonequilibrium 1636-second case shows significantly larger influence from electron impact excitation rates of both atoms and molecules. For all cases, the total uncertainty in radiative heat flux to the wall due to epistemic uncertainty in modeling parameters is 30% as opposed to the erroneously-small uncertainty levels (plus or minus 6%) found when treating model parameter uncertainties as aleatory (due to chance) instead of epistemic (due to lack of knowledge).

  8. Formation and Evaluation of Protective Layer over Magnesium Melt Under CO2/Air Mixtures

    NASA Astrophysics Data System (ADS)

    Emami, Samar; Sohn, Hong Yong

    2015-02-01

    Molten magnesium oxidizes rapidly when exposed to air causing melt loss and handling difficulties. The use of certain additive gases to form a protective MgO layer over a magnesium melt has been proposed. The oxidation behavior of molten magnesium in air that contains various concentrations of CO2 was investigated, including the kinetics of the oxide layer growth. Experiments were performed using a thermogravimetric analysis unit in the temperature range of 943 K to 1043 K (670 °C to 770 °C). Results showed that a thin, coherent, and protective MgO-C layer was formed under the test conditions. The thicknesses of this layer formed under CO2/air ranged from 500 nm to 12 μm. Rate parameters were calculated and a model for the process was developed. The morphology and composition of the surface films were studied using SEM and EDS.

  9. The Impact of Dry Saharan Air on Tropical Cyclone Intensification

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.

    2012-01-01

    The controversial role of the dry Saharan Air Layer (SAL) on tropical storm intensification in the Atlantic will be addressed. The SAL has been argued in previous studies to have potential positive influences on storm development, but most recent studies have argued for a strong suppressing influence on storm intensification as a result of dry air, high stability, increased vertical wind shear, and microphysical impacts of dust. Here, we focus on observations of Hurricane Helene (2006), which occurred during the NASA African Monsoon Multidisciplinary Activities (NAMMA) experiment. Satellite and airborne observations, combined with global meteorological analyses depict the initial environment of Helene as being dominated by the SAL, although with minimal evidence that the SAL air actually penetrated to the core of the disturbance. Over the next several days, the SAL air quickly moved westward and was gradually replaced by a very dry, dust-free layer associated with subsidence. Despite the wrapping of this very dry air around the storm, Helene intensified steadily to a Category 3 hurricane suggesting that the dry air was unable to significantly slow storm intensification. Several uncertainties remain about the role of the SAL in Helene (and in tropical cyclones in general). To better address these uncertainties, NASA will be conducting a three year airborne campaign called the Hurricane and Severe Storm Sentinel (HS3). The HS3 objectives are: To obtain critical measurements in the hurricane environment in order to identify the role of key factors such as large-scale wind systems (troughs, jet streams), Saharan air masses, African Easterly Waves and their embedded critical layers (that help to isolate tropical disturbances from hostile environments). To observe and understand the three-dimensional mesoscale and convective-scale internal structures of tropical disturbances and cyclones and their role in intensity change. The mission objectives will be achieved using

  10. Air-stable few-layer black phosphorus phototransistor for near-infrared detection

    NASA Astrophysics Data System (ADS)

    Na, Junhong; Park, Kichul; Kim, Jin Tae; Choi, Won Kook; Song, Yong-Won

    2017-02-01

    We have demonstrated a few-layer black phosphorus (BP) phototransistor of stable operation in ambient air environment and at near-infrared light (λ = 1550 nm). The air-stable electronic and optoelectronic properties of the few-layer BP phototransistor have been achieved by a proper Al2O3 passivation. The optical identification method and qualitative and quantitative electrical characterizations of the few-layer BP phototransistor in dark state confirmed that the device performance was robust in ambient air, to further chemical treatments, and storage of more than six months. In addition, the low-frequency noise characterizations had revealed that the noise spectral density related to the sensitivity of phototransistor was reduced. Owing to the suppression of interaction between few-layer BP and adsorbates arising from the Al2O3 passivation, a fast rise time of the few-layer BP phototransistor, less than 100 μs, had been observed, demonstrating the intrinsic photoresponse properties of few-layer BP. The low dark current of ˜4 nA at the operation bias and the reasonable responsivity of ˜6 mA W-1 were obtained under the condition lacking adsorbates interactions. Internally, the dark current and responsivity level was tunable by changing the operation bias. Our results are close to the intrinsic properties of the few-layer BP phototransistor, implying that it can be a building block of functioned few-layer BP photodetectors.

  11. Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

    NASA Technical Reports Server (NTRS)

    Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.; Diskin, Glenn S.; Dickerson, Russell R.

    2014-01-01

    Meteorological and air-quality model simulations are analyzed alongside observations to investigate the role of the Chesapeake Bay breeze on surface air quality, pollutant transport, and boundary layer venting. A case study was conducted to understand why a particular day was the only one during an 11-day ship-based field campaign on which surface ozone was not elevated in concentration over the Chesapeake Bay relative to the closest upwind site and why high ozone concentrations were observed aloft by in situ aircraft observations. Results show that southerly winds during the overnight and early-morning hours prevented the advection of air pollutants from the Washington, D.C., and Baltimore, Maryland, metropolitan areas over the surface waters of the bay. A strong and prolonged bay breeze developed during the late morning and early afternoon along the western coastline of the bay. The strength and duration of the bay breeze allowed pollutants to converge, resulting in high concentrations locally near the bay-breeze front within the Baltimore metropolitan area, where they were then lofted to the top of the planetary boundary layer (PBL). Near the top of the PBL, these pollutants were horizontally advected to a region with lower PBL heights, resulting in pollution transport out of the boundary layer and into the free troposphere. This elevated layer of air pollution aloft was transported downwind into New England by early the following morning where it likely mixed down to the surface, affecting air quality as the boundary layer grew.

  12. Control of turbulent boundary layer through air blowing due to external-flow resources

    NASA Astrophysics Data System (ADS)

    Kornilov, V. I.; Boiko, A. V.; Kavun, I. N.

    2015-07-01

    The possibility to control turbulent incompressible boundary layer using air blowing through a finely perforated wall presenting part of the streamlined flat-plate surface was examined. The control was exercised via an action on the state and characteristics of the near-wall flow exerted by controlled (through variation of external-pressure-flow velocity) blowing of air through an air intake installed on the idle side of the plate. A stable reduction of the local values of skin friction coefficient along the model, reaching 50 % at the end of the perforated area, has been demonstrated. The obtained experimental and calculated data are indicative of a possibility to model the process of turbulentboundary-layer control by air blowing due to external-flow resources.

  13. Effects of boundary layer and liquid viscosity and compressible air on sloshing characteristics

    NASA Astrophysics Data System (ADS)

    Zou, Chang-Fang; Wang, De-Yu; Cai, Zhong-Hua

    2015-07-01

    In this paper, numerical investigations for tank sloshing, based on commercial CFD package FLUENT, are performed to study effects of boundary layer grid, liquid viscosity and compressible air on sloshing pressure, wave height and rising time of impact pressure. Also, sloshing experiments for liquids of different viscosity are carried out to validate the numerical results. Through comparison of numerical and experimental results, a computational model including boundary layer grid can predict the sloshing pressure more accurately. Energy dissipation due to viscous friction leads to reduction of sloshing pressure and wave elevation. Sloshing pressure is also reduced because of cushion effect of compressible air. Due to high viscosity damping effect and compressible air effect, the rising time of impact pressure becomes longer. It is also found that liquid viscosity and compressible air influence distribution of dynamic pressure along the vertical tank wall.

  14. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    PubMed

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

  15. Estimation of the Influence of Thin Air Layers on Structures by the Use of Qualitative One-Dimensional Models

    NASA Astrophysics Data System (ADS)

    Chimeno Manguan, M.; Roibas Millan, E.; Simon Hidalgo, F.

    2014-06-01

    Air layers are regions of air between structural elements than can be found in numerous spacecraft structures. The space between folded solar panels and between antennas and a satellite's body are cases of air layers. For some cases, depending on the flexibility of the contiguous structures, the contribution of air layers can modify noticeably the dynamic response of a spacecraft structure. The analysis of these problems in detailed numerical models as Finite and Boundary Element models are characterised by a very small element size because of the requirements imposed by the thickness of the air layers and the fluid-structure interface. Then, a preliminary assessment of the influence of the air layer allows optimizing the development work flow of these elements. This work presents a methodology to preliminarily assess the influence of air layers in the structural response. The methodology is based on the definition of simplified one-dimensional models for the structure and the air gaps. The study of these simple models can be a useful tool to determine the degree of influence of the air layers in the system. Along with the introduction of the methodology a study on several of the model parameters as the number of degrees of freedom for the air layer or the structure is presented. The performance of the methodology is illustrated with results for several cases including actual spacecraft structures.

  16. Review of underground salt attenuation measurements for SalSA

    NASA Astrophysics Data System (ADS)

    Connolly, Amy; SalSA Collaboration

    2012-01-01

    We report on the status of the Salt Sensor Array (SalSA), a proposed experiment for detecting ultra-high energy neutrinos through the radio Cherenkov technique with an array of radio-microwave antennas embedded in a large, naturally occurring salt formation. We review the measurements to date aimed at assessing SalSA's feasibility, including a return visit of the Hockley Salt Mine in Hockley, Texas, and discuss the current status of the project.

  17. Air Processes Resulting in a Surface Layer Pollution in Industrial Regions

    NASA Astrophysics Data System (ADS)

    Lesin, Yu V.; Leshukov, T. V.

    2016-08-01

    The article describes the air quality research in Western Siberia (Kemerovo region). The problem of air quality preservation in the conditions of mining industry intensive development is caused by the weather conditions which lead either to the concentration of pollutants in the surface layer, or to their migration to other geosphere, or to dissipation as a result of convective mixing or advection of air masses. Zoning of the territory in view of the research results provides insight into areas where the greatest risk to human health and life is formed.

  18. Experimental study on flat plate air solar collector using a thin sand layer

    NASA Astrophysics Data System (ADS)

    Lati, Moukhtar; Boughali, Slimane; Bouguettaia, Hamza; Mennouche, Djamel; Bechki, Djamel

    2016-07-01

    A flat plate air solar collector was constructed in the laboratory of New and Renewable Energy in Arid Zones LENREZA, Ouargla University-South East Algeria. The absorber of the flat plate air solar collector was laminated with a thin layer of local sand. This acted as a thermal storage system (packed bed) with a collecting area of 2.15 m2 (0.86 m × 2.5 m). It was noticed that the solar heater integrated with the thermal storage material delivered comparatively higher temperatures; thus, giving a better efficiency than the air heater without the thermal storage system.

  19. Air processed organic photovoltaic devices incorporating a MoOx anode buffer layer

    NASA Astrophysics Data System (ADS)

    Bovill, Edward S. R.; Griffin, Jonathan; Wang, Tao; Kingsley, James W.; Yi, Hunan; Iraqi, Ahmed; Buckley, Alastair R.; Lidzey, David G.

    2013-05-01

    Molybdenum oxide (MoOx) has been shown to act as an efficient hole extraction layer in organic photovoltaic (OPV) devices. However, exposing MoOx films to air is problematic as it is hygroscopic; the uptake of moisture having a negative impact on its electronic properties. Here, we use spectroscopic ellipsometry to characterise the uptake of water, and fabricate PCDTBT:PC70BM based OPVs to determine its effects on device performance. We then show that thermally annealing MoOx reduces its hygroscopicity, permitting it to be processed in air. Using this process, we create air-processsed OPVs having PCEs (power conversion efficiencies) of up to 5.36%.

  20. Layers of air in the water beneath the floating fern Salvinia are exposed to fluctuations in pressure.

    PubMed

    Mayser, Matthias J; Barthlott, Wilhelm

    2014-12-01

    Superhydrophobic, hierarchically structured, technical surfaces (Lotus-effect) are of high scientific and economic interest because of their remarkable properties. Recently, the immense potential of air-retaining superhydrophobic surfaces, for example, for low-friction transport of fluids and drag-reducing coatings of ships has begun to be explored. A major problem of superhydrophobic surfaces mimicking the Lotus-effect is the limited persistence of the air retained, especially under rough conditions of flow. However, there are a variety of floating or diving plant and animal species that possess air-retaining surfaces optimized for durable water-repellency (Salvinia-effect). Especially floating ferns of the genus Salvinia have evolved superhydrophobic surfaces capable of maintaining layers of air for months. Apart from maintaining stability under water, the layer of air has to withstand the stresses of water pressure (up to 2.5 bars). Both of these aspects have an application to create permanent air layers on ships' hulls. We investigated the effect of pressure on air layers in a pressure cell and exposed the air layer to pressures of up to 6 bars. We investigated the suppression of the air layer at increasing pressures as well as its restoration during decreases in pressure. Three of the four examined Salvinia species are capable of maintaining air layers at pressures relevant to the conditions applying to ships' hulls. High volumes of air per surface area are advantageous for retaining at least a partial Cassie-Baxter-state under pressure, which also helps in restoring the air layer after depressurization. Closed-loop structures such as the baskets at the top of the "egg-beater hairs" (see main text) also help return the air layer to its original level at the tip of the hairs by trapping air bubbles.

  1. A laser Doppler system for the remote sensing of boundary layer winds in clear air conditions

    NASA Technical Reports Server (NTRS)

    Lawrence, T. R.; Krause, M. C.; Craven, C. E.; Morrison, L. K.; Thomson, J. A. L.; Cliff, W. C.; Huffaker, R. M.

    1975-01-01

    The system discussed uses a laser Doppler radar in combination with a velocity azimuth display mode of scanning to determine the three-dimensional wind field in the atmospheric boundary layer. An attractive feature of this CW monostatic system is that the ambient aerosol provides a 'sufficient' scattering target to permit operation under clear air conditions. Spatial resolution is achieved by focusing.

  2. Behavior of self-confined spherical layer of light radiation in the air atmosphere

    NASA Astrophysics Data System (ADS)

    Torchigin, V. P.; Torchigin, A. V.

    2004-07-01

    Behavior of thin spherical layer of intensive light in an inhomogeneous atmosphere is considered. It is shown that the behavior is similar to puzzling and mysterious behavior of ball lightnings. Under assumption that ball lightning moves along the gradient of atmosphere air density process of ball lightning penetration in a salon of a flying airplane is analyzed.

  3. Sound transmission through finite lightweight multilayered structures with thin air layers.

    PubMed

    Dijckmans, A; Vermeir, G; Lauriks, W

    2010-12-01

    The sound transmission loss (STL) of finite lightweight multilayered structures with thin air layers is studied in this paper. Two types of models are used to describe the vibro-acoustic behavior of these structures. Standard transfer matrix method assumes infinite layers and represents the plane wave propagation in the layers. A wave based model describes the direct sound transmission through a rectangular structure placed between two reverberant rooms. Full vibro-acoustic coupling between rooms, plates, and air cavities is taken into account. Comparison with double glazing measurements shows that this effect of vibro-acoustic coupling is important in lightweight double walls. For infinite structures, structural damping has no significant influence on STL below the coincidence frequency. In this frequency region, the non-resonant transmission or so-called mass-law behavior dominates sound transmission. Modal simulations suggest a large influence of structural damping on STL. This is confirmed by experiments with double fiberboard partitions and sandwich structures. The results show that for thin air layers, the damping induced by friction and viscous effects at the air gap surfaces can largely influence and improve the sound transmission characteristics.

  4. Preclinical safety evaluation of intravenously administered SAL200 containing the recombinant phage endolysin SAL-1 as a pharmaceutical ingredient.

    PubMed

    Jun, Soo Youn; Jung, Gi Mo; Yoon, Seong Jun; Choi, Yun-Jaie; Koh, Woo Suk; Moon, Kyoung Sik; Kang, Sang Hyeon

    2014-01-01

    Phage endolysins have received increasing attention as potent antibacterial agents. However, although safety evaluation is a prerequisite for the drug development process, a good laboratory practice (GLP)-compliant safety evaluation has not been reported for phage endolysins. A safety evaluation of intravenously administered SAL200 (containing phage endolysin SAL-1) was conducted according to GLP standards. No animals died in any of the safety evaluation studies. In general toxicity studies, intravenously administered SAL200 showed no sign of toxicity in rodent single- and repeated-dose toxicity studies. In the dog repeated-dose toxicity test, there were no abnormal findings, with the exception of transient abnormal clinical signs that were observed in some dogs when daily injection of SAL200 was continued for more than 1 week. In safety pharmacology studies, there were also no signs of toxicity in the central nervous and respiratory system function tests. In the cardiovascular function test, there were no abnormal findings in all tested dogs after the first and second administrations, but transient abnormalities were observed after the third and fourth administrations (2 or 3 weeks after the initial administration). All abnormal findings observed in these safety evaluation studies were slight to mild, were apparent only transiently after injection, and resolved quickly. The safety evaluation results for SAL200 support the implementation of an exploratory phase I clinical trial and underscore the potential of SAL200 as a new drug. We have designed an appropriate phase I clinical trial based on the results of this study.

  5. Cloud layer thicknesses from a combination of surface and upper-air observations

    NASA Technical Reports Server (NTRS)

    Poore, Kirk D.; Wang, Junhong; Rossow, William B.

    1995-01-01

    Cloud layer thicknesses are derived from base and top altitudes by combining 14 years (1975-1988) of surface and upper-air observations at 63 sites in the Northern Hemisphere. Rawinsonde observations are employed to determine the locations of cloud-layer top and base by testing for dewpoint temperature depressions below some threshold value. Surface observations serve as quality checks on the rawinsonde-determined cloud properties and provide cloud amount and cloud-type information. The dataset provides layer-cloud amount, cloud type, high, middle, or low height classes, cloud-top heights, base heights and layer thicknesses, covering a range of latitudes from 0 deg to 80 deg N. All data comes from land sites: 34 are located in continental interiors, 14 are near coasts, and 15 are on islands. The uncertainties in the derived cloud properties are discussed. For clouds classified by low-, mid-, and high-top altitudes, there are strong latitudinal and seasonal variations in the layer thickness only for high clouds. High-cloud layer thickness increases with latitude and exhibits different seasonal variations in different latitude zones: in summer, high-cloud layer thickness is a maximum in the Tropics but a minimum at high latitudes. For clouds classified into three types by base altitude or into six standard morphological types, latitudinal and seasonal variations in layer thickness are very small. The thickness of the clear surface layer decreases with latitude and reaches a summer minimum in the Tropics and summer maximum at higher latitudes over land, but does not vary much over the ocean. Tropical clouds occur in three base-altitude groups and the layer thickness of each group increases linearly with top altitude. Extratropical clouds exhibit two groups, one with layer thickness proportional to their cloud-top altitude and one with small (less than or equal to 1000 m) layer thickness independent of cloud-top altitude.

  6. Performance and microbial ecology of air-cathode microbial fuel cells with layered electrode assemblies.

    PubMed

    Butler, Caitlyn S; Nerenberg, Robert

    2010-05-01

    Microbial fuel cells (MFCs) can be built with layered electrode assemblies, where the anode, proton exchange membrane (PEM), and cathode are pressed into a single unit. We studied the performance and microbial community structure of MFCs with layered assemblies, addressing the effect of materials and oxygen crossover on the community structure. Four MFCs with layered assemblies were constructed using Nafion or Ultrex PEMs and a plain carbon cloth electrode or a cathode with an oxygen-resistant polytetrafluoroethylene diffusion layer. The MFC with Nafion PEM and cathode diffusion layer achieved the highest power density, 381 mW/m(2) (20 W/m(3)). The rates of oxygen diffusion from cathode to anode were three times higher in the MFCs with plain cathodes compared to those with diffusion-layer cathodes. Microsensor studies revealed little accumulation of oxygen within the anode cloth. However, the abundance of bacteria known to use oxygen as an electron acceptor, but not known to have exoelectrogenic activity, was greater in MFCs with plain cathodes. The MFCs with diffusion-layer cathodes had high abundance of exoelectrogenic bacteria within the genus Geobacter. This work suggests that cathode materials can significantly influence oxygen crossover and the relative abundance of exoelectrogenic bacteria on the anode, while PEM materials have little influence on anode community structure. Our results show that oxygen crossover can significantly decrease the performance of air-cathode MFCs with layered assemblies, and therefore limiting crossover may be of particular importance for these types of MFCs.

  7. Air-Stable Humidity Sensor Using Few-Layer Black Phosphorus.

    PubMed

    Miao, Jinshui; Cai, Le; Zhang, Suoming; Nah, Junghyo; Yeom, Junghoon; Wang, Chuan

    2017-03-22

    As a new family member of two-dimensional layered materials, black phosphorus (BP) has attracted significant attention for chemical sensing applications due to its exceptional electrical, mechanical, and surface properties. However, producing air-stable BP sensors is extremely challenging because BP atomic layers degrade rapidly in ambient conditions. In this study, we explored the humidity sensing properties of BP field-effect transistors fully encapsulated by a 6 nm-thick Al2O3 encapsulation layer deposited by atomic layer deposition. The encapsulated BP sensors exhibited superior ambient stability with no noticeable degradation in sensing response after being stored in air for more than a week. Compared with the bare BP devices, the encapsulated ones offered long-term stability with a trade-off in slightly reduced sensitivity. Capacitance-voltage measurement results further reveal that instead of direct charge transfer, the electrostatic gating effect on BP flakes arising from the dipole moment of adsorbed water molecules is the basic mechanism governing the humidity sensing behavior of both bare and encapsulated BP sensors. This work demonstrates a viable approach for achieving air-stable BP-based humidity or chemical sensors for practical applications.

  8. Effects of air pollution on thermal structure and dispersion in an urban planetary boundary layer

    NASA Technical Reports Server (NTRS)

    Viskanta, R.; Johnson, R. O.; Bergstrom, R. W.

    1977-01-01

    The short-term effects of urbanization and air pollution on the transport processes in the urban planetary boundary layer (PBL) are studied. The investigation makes use of an unsteady two-dimensional transport model which has been developed by Viskanta et al., (1976). The model predicts pollutant concentrations and temperature in the PBL. The potential effects of urbanization and air pollution on the thermal structure in the urban PBL are considered, taking into account the results of numerical simulations modeling the St. Louis, Missouri metropolitan area.

  9. Layered perovskite oxide: a reversible air electrode for oxygen evolution/reduction in rechargeable metal-air batteries.

    PubMed

    Takeguchi, Tatsuya; Yamanaka, Toshiro; Takahashi, Hiroki; Watanabe, Hiroshi; Kuroki, Tomohiro; Nakanishi, Haruyuki; Orikasa, Yuki; Uchimoto, Yoshiharu; Takano, Hiroshi; Ohguri, Nobuaki; Matsuda, Motofumi; Murota, Tadatoshi; Uosaki, Kohei; Ueda, Wataru

    2013-07-31

    For the development of a rechargeable metal-air battery, which is expected to become one of the most widely used batteries in the future, slow kinetics of discharging and charging reactions at the air electrode, i.e., oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), respectively, are the most critical problems. Here we report that Ruddlesden-Popper-type layered perovskite, RP-LaSr3Fe3O10 (n = 3), functions as a reversible air electrode catalyst for both ORR and OER at an equilibrium potential of 1.23 V with almost no overpotentials. The function of RP-LaSr3Fe3O10 as an ORR catalyst was confirmed by using an alkaline fuel cell composed of Pd/LaSr3Fe3O10-2x(OH)2x·H2O/RP-LaSr3Fe3O10 as an open circuit voltage (OCV) of 1.23 V was obtained. RP-LaSr3Fe3O10 also catalyzed OER at an equilibrium potential of 1.23 V with almost no overpotentials. Reversible ORR and OER are achieved because of the easily removable oxygen present in RP-LaSr3Fe3O10. Thus, RP-LaSr3Fe3O10 minimizes efficiency losses caused by reactions during charging and discharging at the air electrode and can be considered to be the ORR/OER electrocatalyst for rechargeable metal-air batteries.

  10. Algal layer ratios as indicators of air pollutant effects in Permelia sulcata

    USGS Publications Warehouse

    Bennett, J.P.

    2002-01-01

    Parmelia sulcata Taylor is generally believed to be fairly pollution tolerant, and consequently it is sometimes collected in urban and/or polluted localities. The condition of these specimens, however, is not always luxuriant and healthy. This study tested the hypothesis that total thallus and algal layer thickness, and the algal layer ratio would be thinner in polluted areas, thus allowing these characters to be used a indicators of air pollutant effects. Herbarium specimens were studied from 16 different localities varying in pollution level. The thallus and algal layers and ratio were not affected by year or locality of sampling, but decreased 11, 31 and 21% respectively between low and high pollution level localities. These results agreed with earlier studies using other species, but further work is needed to clarify the effects of geography and substrate on these phenomena.

  11. Air-sea fluxes and surface layer turbulence around a sea surface temperature front

    NASA Technical Reports Server (NTRS)

    Friehe, C. A.; Shaw, W. J.; Davidson, K. L.; Rogers, D. P.; Large, W. G.; Stage, S. A.; Crescenti, G. H.; Khalsa, S. J. S.; Greenhut, G. K.; Li, F.

    1991-01-01

    The observed effects of sharp changes in sea surface temperature (SST) on the air-sea fluxes, surface roughness, and the turbulence structure in the surface layer and the marine atmospheric boundary layer are discussed. In situ flux and turbulence observations were carried out from three aircraft and two ships within the FASINEX framework. Three other aircraft used remote sensors to measure waves, microwave backscatter, and lidar signatures of cloud tops. Descriptions of the techniques, intercomparison of aircraft and ship flux data, and use of different methods for analyzing the fluxes from the aircraft data are described. Changing synoptic weather on three successive days yielded cases of wind direction both approximately parallel and perpendicular to a surface temperature front. For the wind perpendicular to the front, wind over both cold-to-warm and warm-to-cold surface temperatures occurred. Model results consistent with the observations suggest that an internal boundary layer forms at the SST.

  12. Long-term study of air urban quality together with mixing layer height

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Ling, Hong; Münkel, Christoph; Emeis, Stefan

    2013-10-01

    Air pollution episodes in urban areas often occur during low wind speeds and low mixing layer height (MLH) and can not only be ascribed to increased local anthropogenic emissions. The continuous knowledge of MLH is supporting the understanding of processes directing air quality. If the MLH is located near to the ground, which occurs mainly during winter and night-time, air pollution can be high due to a strongly limited air mass dilution. The Vaisala ceilometer CL31, which is an eye-safe commercial mini-lidar system, is used for long-term continuous remote sensing of MLH. The ceilometer measurements provide information about the range-dependent aerosol concentration; gradient minima within this profile mark the borders of mixed layers. Special software for this ceilometer developed with MATLAB provides routine retrievals of lower atmosphere layering from vertical profiles of laser backscatter data. To study the gaseous pollutants and those compounds important for secondary aerosol formation like NO and NO2 as well as O3 The data retrieval software is extended to improve remote sensing of MLH. The original 10-minute-interval values are used to calculate continuous 1-hour-mean values. Gaps and strong variations of the original data are considered. The results of investigations of the meteorological influences and the role of emissions within the context of the air quality in Augsburg are discussed. a DOAS is operated since March 2012 in Augsburg. Information about different road traffic emissions is provided by this one instrument i.e. by path-integrated air pollution information in different directions. The DOAS contains an analyser and an emitter/receiver unit pointing to three retroreflectors. The retroreflectors were installed at lamp masts so that the paths were about 10 m above street level and perpendicular across the streets. The emitter/receiver unit was in a distance of about 20 m to an in situ air pollution measurement station at the ground. Ground

  13. Boundary layer warming by condensation - Air-sea interaction during an extreme cold air outbreak from the eastern coast of the United States

    NASA Technical Reports Server (NTRS)

    Grossman, Robert L.

    1988-01-01

    Studies on an intense cold air outbreak that took place after a cold air cyclogenesis on January 27, 1986 are reviewed. Particular attention is given to data obtained during a multiaircraft research mission carried out on January 28, 1986 as part of the Genesis of Atlantic Lows Experiment. It was found that condensation heating of the subcloud layer air was comparable to heating by turbulent flux divergence.

  14. The role of boundary layer schemes in meteorological and air quality simulations of the Taiwan area

    NASA Astrophysics Data System (ADS)

    Cheng, Fang-Yi; Chin, Shan-Chieh; Liu, Tsun-Hsien

    2012-07-01

    Adequate air quality modeling is reliant on accurate meteorological simulations especially in the planetary boundary layer (PBL). To understand how the boundary layer processes affect the mixing and transport of air pollutants, the sensitivity of Weather Research Forecasting (WRF) model with different PBL schemes (YSU and MYJ) is utilized. Community Multiscale Air Quality (CMAQ) modeling system is performed subsequently to study the effects of the PBL physical processes on the meteorological and air quality simulations. A comparison is made of two distinct atmospheric conditions. Case 1 considers the influence of the Asian continental outflow where air pollutants carried by long-range transport (LRT) to Taiwan. The variation in ozone (O3) concentration between the two sensitivity runs is mainly caused by the PBL height difference with WRF-MYJ predicts much deeper PBL height near the frontal low-pressure region than does the WRF-YSU. Case 2 is associated with the land-sea breeze flow. In this situation O3 is locally produced from the western side of the country where major metropolitan cities and highways are located. Distinctions in O3 are caused by difference in the strength of the land-sea breeze flow between the two runs. At night the WRF-YSU predicts a weaker offshore land breeze than does the WRF-MYJ near the western coastline. During the day, the WRF-YSU predicts a stronger sea breeze near the offshore area than does the WRF-MYJ, while over the landside, the WRF-YSU predicts a lower wind speed than does the WRF-MYJ.

  15. Wintertime boundary-layer structure and air sea interaction over the Japan/East Sea

    NASA Astrophysics Data System (ADS)

    Khelif, Djamal; Friehe, Carl A.; Jonsson, Haflidi; Wang, Qing; Rados, Konstantinos

    2005-06-01

    The wintertime meteorology over the Japan/East Sea (JES) is characterized by episodic strong northwesterly winds known as "cold-air outbreaks" resulting from the incursion of dry and cold air masses from the Eurasian continent. These were found by previous studies (mostly based on indirect methods) to greatly enhance the air-sea interaction and, in particular an area about 150 km in diameter off Vladivostok was identified as the Flux Center. Aircraft in situ measurements of turbulent fluxes and mean meteorological variables were made during the winter 2000. The existence and location of the Flux Center were confirmed although the turbulent sensible and latent-heat fluxes were not as high as previously found due to the air temperature being several degrees warmer. However, the stress was found to be significantly larger as a result of higher wind speeds. The internal boundary layer was found to grow linearly with the square root of offshore fetch, with a growth rate of 2.49m for an intense cold-air outbreak and 2.06m for a moderate one. A persistent initial decrease in the inversion height was observed at 41.86∘N,132.6∘E and may be attributable to the fanning out of the jet flow out of the Vladivostok gap as it expands onto the open ocean. The radiometric skin sea-surface temperature in the Flux Center exhibited large variability in the 0-4 °C range and was positively correlated with the total turbulent (latent+sensible) heat loss. Meteorological variables and surface fluxes results from Naval Research Laboratory Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) model compared reasonably, while the predictions of the internal boundary layer height were markedly lower than the observations.

  16. Numerical study of shock-wave/boundary layer interactions in premixed hydrogen-air hypersonic flows

    NASA Technical Reports Server (NTRS)

    Yungster, Shaye

    1990-01-01

    A computational study of shock wave/boundary layer interactions involving premixed combustible gases, and the resulting combustion processes is presented. The analysis is carried out using a new fully implicit, total variation diminishing (TVD) code developed for solving the fully coupled Reynolds-averaged Navier-Stokes equations and species continuity equations in an efficient manner. To accelerate the convergence of the basic iterative procedure, this code is combined with vector extrapolation methods. The chemical nonequilibrium processes are simulated by means of a finite-rate chemistry model for hydrogen-air combustion. Several validation test cases are presented and the results compared with experimental data or with other computational results. The code is then applied to study shock wave/boundary layer interactions in a ram accelerator configuration. Results indicate a new combustion mechanism in which a shock wave induces combustion in the boundary layer, which then propagates outwards and downstream. At higher Mach numbers, spontaneous ignition in part of the boundary layer is observed, which eventually extends along the entire boundary layer at still higher values of the Mach number.

  17. Modelling the effects of microgravity on the permeability of air interface respiratory epithelial cell layers

    NASA Astrophysics Data System (ADS)

    dos Santos, Marlise A.; Bosquillon, Cynthia; Russomano, Thais; Sundaresan, Alamelu; Falcão, Felipe; Marriott, Christopher; Forbes, Ben

    2010-09-01

    Although it has been suggested that microgravity might affect drug absorption in vivo, drug permeability across epithelial barriers has not yet been investigated in vitro during modelled microgravity. Therefore, a cell culture/diffusion chamber was designed specifically to accommodate epithelial cell layers in a 3D-clinostat and allow epithelial permeability to be measured under microgravity conditions in vitro with minimum alteration to established cell culture techniques. Human respiratory epithelial Calu-3 cell layers were used to model the airway epithelium. Cells grown at an air interface in the diffusion chamber from day 1 or day 5 after seeding on 24-well polyester Transwell cell culture inserts developed a similar transepithelial electrical resistance (TER) to cells cultured in conventional cell culture plates. Confluent Calu-3 layers exposed to modelled microgravity in the 3D-clinostat for up to 48 h maintained their high TER. The permeability of the paracellular marker 14C-mannitol was unaffected after a 24 h rotation of the cell layers in the 3D-clinostat, but was increased 2-fold after 48 h of modelled microgravity. It was demonstrated that the culture/diffusion chamber developed is suitable for culturing epithelial cell layers and, when subjected to rotation in the 3D-clinostat, will be a valuable in vitro system in which to study the influence of microgravity on epithelial permeability and drug transport.

  18. Air-Stable flexible organic light-emitting diodes enabled by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Lin, Yuan-Yu; Chang, Yi-Neng; Tseng, Ming-Hung; Wang, Ching-Chiun; Tsai, Feng-Yu

    2015-01-01

    Organic light-emitting diodes (OLED) are an energy-efficient light source with many desirable attributes, besides being an important display of technology, but its practical application has been limited by its low air-stability. This study demonstrates air-stable flexible OLEDs by utilizing two atomic-layer-deposited (ALD) films: (1) a ZnO film as both a stable electron-injection layer (EIL) and as a gas barrier in plastics-based OLED devices, and (2) an Al2O3/ZnO (AZO) nano-laminated film for encapsulating the devices. Through analyses of the morphology and electrical/gas-permeation properties of the films, we determined that a low ALD temperature of 70 °C resulted in optimal EIL performance from the ZnO film and excellent gas-barrier properties [water vapor transmission rate (WVTR) <5 × 10-4 g m-2 day-1] from both the ZnO EIL and the AZO encapsulating film. The low-temperature ALD processes eliminated thermal damage to the OLED devices, which were severe when a 90 °C encapsulation process was used, while enabling them to achieve an air-storage lifetime of >10 000 h.

  19. Enhanced air pollution via aerosol-boundary layer feedback in China.

    PubMed

    Petäjä, T; Järvi, L; Kerminen, V-M; Ding, A J; Sun, J N; Nie, W; Kujansuu, J; Virkkula, A; Yang, X-Q; Fu, C B; Zilitinkevich, S; Kulmala, M

    2016-01-12

    Severe air pollution episodes have been frequent in China during the recent years. While high emissions are the primary reason for increasing pollutant concentrations, the ultimate cause for the most severe pollution episodes has remained unclear. Here we show that a high concentration of particulate matter (PM) will enhance the stability of an urban boundary layer, which in turn decreases the boundary layer height and consequently cause further increases in PM concentrations. We estimate the strength of this positive feedback mechanism by combining a new theoretical framework with ambient observations. We show that the feedback remains moderate at fine PM concentrations lower than about 200 μg m(-3), but that it becomes increasingly effective at higher PM loadings resulting from the combined effect of high surface PM emissions and massive secondary PM production within the boundary layer. Our analysis explains why air pollution episodes are particularly serious and severe in megacities and during the days when synoptic weather conditions stay constant.

  20. A 3D Computational Study on the Air-Blast Atomization of a Planar Liquid Layer

    NASA Astrophysics Data System (ADS)

    Chiodi, Robert; Desjardins, Olivier

    2016-11-01

    The air-blast atomization of a planar liquid layer is a complex fluid phenomenon involving the destabilization of a low speed liquid layer by a high speed gas coflow. While progress has been made in recent years on understanding the instability of the liquid surface, it remains difficult to accurately predict using stability analysis and requires special expertise and equipment to perform thorough experiments. Simulations provide an excellent way to conduct parametric studies to determine the effect of splitter plate geometry and momentum flux ratio on the frequency and wavelengths of instability, however, they are extremely difficult due to the high density ratio and large range of length and time scales present in the flow. Using an accurate conservative level set method in conjunction with a newly reformulated reinitialization equation, we perform 3D simulations of the air-blast atomization of a planar liquid layer and compare them to experiments. We then go on to explore the role momentum flux ratio plays in the longitudinal and transverse wavelengths of instability.

  1. Air emission into a water shear layer through porous media. Part 2: Cavitation induced pressure attenuation

    SciTech Connect

    Myer, E.C.; Marboe, R.C.

    1994-12-31

    Cavitation near the casing of a hydroturbine can lead to damage through both cavitation erosion and mechanical vibration of the casing and the associated piping. Cavitation erosion results from the collapse of cavitation bubbles on or near a surface such as the casing wall. Mechanical vibrations transmitted to the casing directly through the collapse of bubbles on the casing wall indirectly through a coupling of the acoustic pressure pulse due to a nearby collapse on the turbine blade. Air emission along the casing can reduce the intensity of the tip vortex and the gap cavitation through ventilation of the cavity. Reduction in the machinery vibration is obtained by reduction of the intensity of cavitation bubble collapse and attenuation and scattering of the radiated acoustic pressure. This requires a bubble layer which may be introduced in the vicinity of the turbine blade tips. This layer remains for some distance downstream of the blades and is effective for attenuation of tip vortex induced noise and blade surface cavitation noise. For the purpose of characterizing this bubble layer within a water pipe, the authors spanned a pipe with a two dimensional hydrofoil and emitted air through porous media (20 and 100 micron porosity sintered stainless steel) into the shear flow over the hydrofoil. This paper is limited to an investigation of the attenuation of acoustic pressure propagating to the casing rather than the reduction in acoustic source level due to collapse cushioning effects.

  2. 77 FR 46022 - Manti-La Sal National Forest Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-02

    ... No: 2012-18849] DEPARTMENT OF AGRICULTURE Forest Service Manti-La Sal National Forest Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Manti-La Sal..., Manti-La Sal National Forest, 599 West Price River Drive, Price, UT 84501. Comments may also be sent...

  3. 76 FR 28416 - Manti-La Sal National Forest Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-17

    ... Forest Service Manti-La Sal National Forest Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Manti-La Sal National Forest Resource Advisory Committee will..., Utah. Written comments should be sent to Rosann Fillmore, Manti-La Sal National Forest, 599 West...

  4. Mixing layer height and its implications for air pollution over Beijing, China

    NASA Astrophysics Data System (ADS)

    Tang, Guiqian; Zhang, Jinqiang; Zhu, Xiaowan; Song, Tao; Münkel, Christoph; Hu, Bo; Schäfer, Klaus; Liu, Zirui; Zhang, Junke; Wang, Lili; Xin, Jinyuan; Suppan, Peter; Wang, Yuesi

    2016-03-01

    The mixing layer is an important meteorological factor that affects air pollution. In this study, the atmospheric mixing layer height (MLH) was observed in Beijing from July 2009 to December 2012 using a ceilometer. By comparison with radiosonde data, we found that the ceilometer underestimates the MLH under conditions of neutral stratification caused by strong winds, whereas it overestimates the MLH when sand-dust is crossing. Using meteorological, PM2.5, and PM10 observational data, we screened the observed MLH automatically; the ceilometer observations were fairly consistent with the radiosondes, with a correlation coefficient greater than 0.9. Further analysis indicated that the MLH is low in autumn and winter and high in spring and summer in Beijing. There is a significant correlation between the sensible heat flux and MLH, and the diurnal cycle of the MLH in summer is also affected by the circulation of mountainous plain winds. Using visibility as an index to classify the degree of air pollution, we found that the variation in the sensible heat and buoyancy term in turbulent kinetic energy (TKE) is insignificant when visibility decreases from 10 to 5 km, but the reduction of shear term in TKE is near 70 %. When visibility decreases from 5 to 1 km, the variation of the shear term in TKE is insignificant, but the decrease in the sensible heat and buoyancy term in TKE is approximately 60 %. Although the correlation between the daily variation of the MLH and visibility is very poor, the correlation between them is significantly enhanced when the relative humidity increases beyond 80 %. This indicates that humidity-related physicochemical processes is the primary source of atmospheric particles under heavy pollution and that the dissipation of atmospheric particles mainly depends on the MLH. The presented results of the atmospheric mixing layer provide useful empirical information for improving meteorological and atmospheric chemistry models and the forecasting

  5. Experimental modeling of air blowing into a turbulent boundary layer using an external pressure flow

    NASA Astrophysics Data System (ADS)

    Kornilov, V. I.; Boiko, A. V.

    2016-10-01

    We have experimentally investigated the characteristics of an incompressible turbulent boundary layer on a plane plate upon the passive blowing of air through a fine-perforated surface and flushing it by supplying an external pressure flow through a wind tunnel using an intake device equipped with an attachment for draining the boundary layer on the inactive side of the plate. A stable decrease in the local values of the surface coefficient of friction, which reaches 80% at the end of the perforated region, has been detected over the length of the plate. The possibility of controlling surface friction by changing the velocity of the external flow and selecting the meshes and filters at the inlet to the flow passage has been demonstrated.

  6. Conversion of evaporated In2S3 layers into In2O3 by air annealing

    NASA Astrophysics Data System (ADS)

    Gopinath, G. R.; Revathi, N.; Uthanna, S.; Reddy, K. T. Ramakrishna

    2012-06-01

    In2S3 films have been prepared by close spaced evaporation onto Corning glass at a substrate temperature of 350oC and annealed in air at different temperatures that vary in the range, 250 - 400°C. The composition and structural properties of the layers were investigated using appropriate techniques. The studies indicated a phase conversion from tetragonal In2S3 to cubic In2O3 with the increase of annealing temperature. The results are presented and discussed.

  7. Measurements of mixing layer height variability during the Ligurian air-sea interaction experiment (LASIE '07)

    NASA Astrophysics Data System (ADS)

    Förster, J.

    2009-09-01

    Air-sea interaction processes play a dominant role with respect to detection ranges of shipborne radar and infrared sensor systems. Especially in the littoral most often temperature and humidity gradients affect propagation paths and are the reason for abnormal phenomena such as ducting or mirage. Besides refractivity, spray and aerosols ejected from the sea surface can further degrade the quality of shipborne surveillance systems. Thus environmental effects might seriously hamper ship self defense. During the Ligurian Air-Sea Interaction Experiment (LASIE '07 - 16.06.-26.06.2007) the Federal Armed Forces Underwater Acoustics and Marine Geophysics Research Institute (FWG) carried out simultaneous in-situ measurements of meteorological and oceanographic parameters to study air-sea interaction processes with respect to littoral boundary layer variability. The characterization of the environment included both, in-situ measurements of atmospheric and sea surface parameters. Investigations were carried out on board RV PLANET, RV URANIA and at the ODAS-Italy1 buoy of the Italian National Council of Research (CNR). On board RV PLANET the sea surface and meteorological conditions were analyzed by two multi-sensor buoys, ship sensors and radiosondes. Emphasis was given to the vertical structure of the Marine Boundary Layer (MBL) and its variability. It was analyzed by a one lense lidar ceilometer CL31, a tethersonde system TT12 and radiosondes RS92 (Vaisala). The latter were launched every three hours. The TT12 consisted of three radiosondes, which could be adapted to separate altitudes of special interest. The experiment was characterized by changing meteorological conditions resulting in offshore and onshore blowing winds. In the first case the air temperature TAir was higher than the sea surface temperature TWater leading to a very stable surface layer. This situation was associated with a strong temperature inversion and a very clear atmosphere with a visibility of

  8. Influence of Gas Turbulence on the Instability of an Air-Water Mixing Layer.

    PubMed

    Matas, Jean-Philippe; Marty, Sylvain; Dem, Mohamed Seydou; Cartellier, Alain

    2015-08-14

    We present the first evidence of the direct influence of gas turbulence on the shear instability of a planar air-water mixing layer. We show with two different experiments that increasing the level of velocity fluctuations in the gas phase continuously increases the frequency of the instability, up to a doubling of frequency for the largest turbulence intensity investigated. A modified spatiotemporal stability analysis taking turbulence into account via a simple Reynolds stress closure provides the right trend and magnitude for this effect.

  9. Atmospheric Boundary Layer Height Evolution with Lidar in Buenos Aires from 2008 to 2011

    NASA Astrophysics Data System (ADS)

    Pawelko, Ezequiel Eduardo; Salvador, Jacobo Omar; Ristori, Pablo Roberto; Pallotta, Juan Vicente; Otero, Lidia Ana; Quel, Eduardo Jaime

    2016-06-01

    The analysis of the atmospheric boundary layer top height evolution is obtained from 2008 to 2011 in Buenos Aires using the multiwavelength lidar located at CEILAP (CITEDEF-CONICET) (34°33' S; 58°30' W; 17 m asl). Algorithms recognition based on covariance wavelet transform are applied to obtain seasonal statistics. This method is being evaluated for use in the Lidar Network in Argentina and it is being deployed in Patagonia region currently. The technique operates in real time in both low and high aerosol loads and with almost no human supervision.

  10. Investigation of wintertime cold-air pools and aerosol layers in the Salt Lake Valley using a lidar ceilometer

    NASA Astrophysics Data System (ADS)

    Young, Joseph Swyler

    This thesis investigates the utility of lidar ceilometers, a type of aerosol lidar, in improving the understanding of meteorology and air quality in persistent wintertime stable boundary layers, or cold-air pools, that form in urbanized valley and basin topography. This thesis reviews the scientific literature to survey the present knowledge of persistent cold-air pools, the operating principles of lidar ceilometers, and their demonstrated utility in meteorological investigations. Lidar ceilometer data from the Persistent Cold-Air Pool Study (PCAPS) are then used with meteorological and air quality data from other in situ and remote sensing equipment to investigate cold-air pools that formed in Utah's Salt Lake Valley during the winter of 2010-2011. The lidar ceilometer is shown to accurately measure aerosol layer depth and aerosol loading, when compared to visual observations. A linear relationship is found between low-level lidar backscatter and surface particulate measurements. Convective boundary layer lidar analysis techniques applied to cold-air pool ceilometer profiles can detect useful layer characteristics. Fine-scale waves are observed and analyzed within the aerosol layer, with emphasis on Kelvin-Helmholz waves. Ceilometer aerosol backscatter profiles are analyzed to quantify and describe mixing processes in persistent cold-air pools. Overlays of other remote and in-situ observations are combined with ceilometer particle backscatter to describe specific events during PCAPS. This analysis describes the relationship between the aerosol layer and the valley inversion as well as interactions with large-scale meteorology. The ceilometer observations of hydrometers are used to quantify cloudiness and precipitation during the project, observing that 50% of hours when a PCAP was present had clouds or precipitation below 5 km above ground level (AGL). Then, combining an objective technique for determining hourly aerosol layer depths and correcting this

  11. SalK/SalR, a Two-Component Signal Transduction System, Is Essential for Full Virulence of Highly Invasive Streptococcus suis Serotype 2

    PubMed Central

    Pan, Xiuzhen; Cheng, Gong; Wang, Jing; Ge, Junchao; Zheng, Feng; Cao, Min; Dong, Yaqing; Liu, Di; Wang, Jufang; Lin, Ying; Du, Hongli; Gao, George F.; Wang, Xiaoning; Hu, Fuquan; Tang, Jiaqi

    2008-01-01

    Background Streptococcus suis serotype 2 (S. suis 2, SS2) has evolved into a highly infectious entity, which caused the two recent large-scale outbreaks of human SS2 epidemic in China, and is characterized by a toxic shock-like syndrome. However, the molecular pathogenesis of this new emerging pathogen is still poorly understood. Methodology/Principal Findings 89K is a newly predicted pathogenicity island (PAI) which is specific to Chinese epidemic strains isolated from these two SS2 outbreaks. Further bioinformatics analysis revealed a unique two-component signal transduction system (TCSTS) located in the candidate 89K PAI, which is orthologous to the SalK/SalR regulatory system of Streptococcus salivarius. Knockout of salKR eliminated the lethality of SS2 in experimental infection of piglets. Functional complementation of salKR into the isogenic mutant ΔsalKR restored its soaring pathogenicity. Colonization experiments showed that the ΔsalKR mutant could not colonize any susceptible tissue of piglets when administered alone. Bactericidal assays demonstrated that resistance of the mutant to polymorphonuclear leukocyte (PMN)-mediated killing was greatly decreased. Expression microarray analysis exhibited a transcription profile alteration of 26 various genes down-regulated in the ΔsalKR mutant. Conclusions/Significance These findings suggest that SalK/SalR is requisite for the full virulence of ethnic Chinese isolates of highly pathogenic SS2, thus providing experimental evidence for the validity of this bioinformatically predicted PAI. PMID:18461172

  12. Tsunami vulnerability and damage assessment in the coastal area of Rabat and Salé, Morocco

    NASA Astrophysics Data System (ADS)

    Atillah, A.; El Hadani, D.; Moudni, H.; Lesne, O.; Renou, C.; Mangin, A.; Rouffi, F.

    2011-12-01

    This study, a companion paper to Renou et al. (2011), focuses on the application of a GIS-based method to assess building vulnerability and damage in the event of a tsunami affecting the coastal area of Rabat and Salé, Morocco. This approach, designed within the framework of the European SCHEMA project (www.schemaproject.org) is based on the combination of hazard results from numerical modelling of the worst case tsunami scenario (inundation depth) based on the historical Lisbon earthquake of 1755 and the Portugal earthquake of 1969, together with vulnerability building types derived from Earth Observation data, field surveys and GIS data. The risk is then evaluated for this highly concentrated population area characterized by the implementation of a vast project of residential and touristic buildings within the flat area of the Bouregreg Valley separating the cities of Rabat and Salé. A GIS tool is used to derive building damage maps by crossing layers of inundation levels and building vulnerability. The inferred damage maps serve as a base for elaborating evacuation plans with appropriate rescue and relief processes and to prepare and consider appropriate measures to prevent the induced tsunami risk.

  13. Characterization of SAL605 negative resist at {lambda}=13 nm

    SciTech Connect

    La Fontaine, B.; Ciarlo, D.; Gaines, D.P.; Kania, D.R.

    1996-05-24

    We have characterized the response of the negative resist SAL605 in the extreme ultraviolet ({lambda}=13 nm). The sensitivity was found to be {approx}1 mJ/cm{sup 3} for all conditions studied. We have identified processing conditions leading to high ({gamma}{gt}4) contrast. The resist response was modeled using Prolith/2 and the development parameters were obtained from the exposure curves.

  14. Teaching Is a Fight: An Interview with Sal Castro

    ERIC Educational Resources Information Center

    Ochoa, Gilda L.

    2011-01-01

    In June, more than 40 years after the Los Angeles Unified School District tried to fire Sal Castro for his leadership of the 1968 Chicana/o Blowouts, it came full circle and named a middle school after him. As a young teacher, Castro was a key organizer of the 1968 student walkouts (called "blowouts" by the youth), when as many as 40,000…

  15. On the Acousto-Elastic Behaviour of Double-Wall Panels with a Viscothermal Air Layer

    NASA Astrophysics Data System (ADS)

    BASTEN, T. G. H.; VAN DER HOOGT, P. J. M.; SPIERING, R. M. E. J.; TIJDEMAN, H.

    2001-06-01

    In this paper, an analytical two-dimensional model is presented for the acousto-elastic behaviour of double-wall panels with a thin viscothermal air layer. The model for the air is based on the low reduced frequency solution as introduced by Beltman (1998 Ph.D. Thesis, University of Twente; 1999 Journal of Sound and Vibration227, (Part I), 555-586;227 (Part II), 587-609; Beltman et al., 1997 Journal of Sound and Vibration206 , 217-241; 1998 Journal of Sound and Vibration216, 159-185) [1-5] and includes, apart from inertia and compressibility, the effects of viscosity and thermal conductivity. With the analytical model eigenfrequencies were determined and response and transmission calculations were performed. It is shown that high damping coefficients for double-wall panels can be obtained by using the viscous characteristics of the fluid layer. The model makes it possible to conduct parameter analyses very easily and efficiently, which is important for design studies. Furthermore, the model gives exact results for both the vibrational behaviour and the sound transmission characteristics of double-wall panels which can be used to validate numerical codes.

  16. Temperature differences in the air layer close to a road surface

    NASA Astrophysics Data System (ADS)

    Bogren, Jörgen; Gustavsson, Torbjörn; Karlsson, Maria

    2001-12-01

    In this study, profiles of temperature and humidity (<250 cm above the road and 5 m into the surroundings) have been used to examine the development of temperature differences in the air layer close to the road. Temperature, humidity and wind profiles were measured, together with net radiation and observations of road surface state, at a test site at Road 45, Surte, Sweden. Measured temperature differences were compared with present weather, preceding weather, surface status, wind direction and other parameters thought to be important for the development of temperature differences. The results showed that large temperature differences (1-3 °C between 250 cm and 10 cm above the road) occurred when there was a high risk of slipperiness caused by hoarfrost, snow or ice on the road. The temperature differences between different levels were associated with the exchange of humidity and temperature between the air layer and the road surface. The 10 cm level reflected the surface processes well. Higher levels were influenced by the surroundings because of turbulence and advection. This study emphasises the need for measurements to be taken at a height and place that reflects the processes at the road surface.

  17. Silver-Copper Nanoalloy Catalyst Layer for Bifunctional Air Electrodes in Alkaline Media.

    PubMed

    Wu, Xiaoqiang; Chen, Fuyi; Jin, Yachao; Zhang, Nan; Johnston, Roy L

    2015-08-19

    A carbon-free and binder-free catalyst layer composed of a Ag-Cu nanoalloy on Ni foam was used as the air cathode in a zinc-air battery for the first time. The Ag-Cu catalyst was prepared using pulsed laser deposition. The structures of the catalysts were found to consist of crystalline Ag-Cu nanoalloy particles with an average size of 2.58 nm embedded in amorphous Cu films. As observed in the X-ray photoelectron spectra, the Ag 3d core levels shifted to higher binding energies, whereas the Cu 2p core levels shifted to lower binding energies, indicating alloying of the silver and copper. Rotating disk electrode measurements indicated that the oxygen reduction reaction (ORR) proceeded through a four-electron pathway on the Ag50Cu50 and Ag90Cu10 nanoalloy catalysts in alkaline solution. Moreover, the catalytic activity of Ag50Cu50 in the ORR is more efficient than that of Ag90Cu10. By performing charge and discharge cycling measurements, the Ag50Cu50 catalyst layer was confirmed to have a maximum power density of approximately 86.3 mW cm(-2) and an acceptable cell voltage at 0.863 V for current densities up to 100 mA cm(-2) in primary zinc-air batteries. In addition, a round-trip efficiency of approximately 50% at a current density of 20 mA cm(-2) was also obtained in the test.

  18. Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows

    DOEpatents

    Farrington, Robert B.; Anderson, Ren

    2001-01-01

    The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

  19. Mixing layer height measurements determines influence of meteorology on air pollutant concentrations in urban area

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Blumenstock, Thomas; Bonn, Boris; Gerwig, Holger; Hase, Frank; Münkel, Christoph; Nothard, Rainer; von Schneidemesser, Erika

    2015-10-01

    Mixing layer height (MLH) is a key parameter to determine the influence of meteorological parameters upon air pollutants such as trace gas species and particulate concentrations near the surface. Meteorology, and MLH as a key parameter, affect the budget of emission source strengths, deposition, and accumulation. However, greater possibilities for the application of MLH data have been identified in recent years. Here, the results of measurements in Berlin in 2014 are shown and discussed. The concentrations of NO, NO2, O3, CO, PM1, PM2.5, PM10 and about 70 volatile organic compounds (anthropogenic and biogenic of origin) as well as particle size distributions and contributions of SOA and soot species to PM were measured at the urban background station of the Berlin air quality network (BLUME) in Nansenstr./Framstr., Berlin-Neukölln. A Vaisala ceilometer CL51, which is a commercial mini-lidar system, was applied at that site to detect the layers of the lower atmosphere in real time. Special software for these ceilometers with MATLAB provided routine retrievals of MLH from vertical profiles of laser backscatter data. Five portable Bruker EM27/SUN FTIR spectrometers were set up around Berlin to detect column averaged abundances of CO2 and CH4 by solar absorption spectrometry. Correlation analyses were used to show the coupling of temporal variations of trace gas compounds and PM with MLH. Significant influences of MLH upon NO, NO2, PM10, PM2.5, PM1 and toluene (marker for traffic emissions) concentrations as well as particle number concentrations in the size modes 70 - 100 nm, 100 - 200 nm and 200 - 500 nm on the basis of averaged diurnal courses were found. Further, MLH was taken as important auxiliary information about the development of the boundary layer during each day of observations, which was required for the proper estimation of CO2 and CH4 source strengths from Berlin on the basis of atmospheric column density measurements.

  20. Doped lanthanum nickelates with a layered perovskite structure as bifunctional cathode catalysts for rechargeable metal-air batteries.

    PubMed

    Jung, Kyu-Nam; Jung, Jong-Hyuk; Im, Won Bin; Yoon, Sukeun; Shin, Kyung-Hee; Lee, Jong-Won

    2013-10-23

    Rechargeable metal-air batteries have attracted a great interest in recent years because of their high energy density. The critical challenges facing these technologies include the sluggish kinetics of the oxygen reduction-evolution reactions on a cathode (air electrode). Here, we report doped lanthanum nickelates (La2NiO4) with a layered perovskite structure that serve as efficient bifunctional electrocatalysts for oxygen reduction and evolution in an aqueous alkaline electrolyte. Rechargeable lithium-air and zinc-air batteries assembled with these catalysts exhibit remarkably reduced discharge-charge voltage gaps (improved round-trip efficiency) as well as high stability during cycling.

  1. A numerical study of ignition in the supersonic hydrogen/air laminar mixing layer

    SciTech Connect

    Nishioka, M.; Law, C.K.

    1997-01-01

    The ignition evolution in the supersonic nonpremixed hydrogen/air laminar mixing layer, consisting of a relatively hot, fast air stream next to a cold, slower hydrogen stream, was computationally simulated using detailed transport and chemical reaction mechanisms and compared with results from asymptotic analysis with reduced mechanisms. The study emphasizes identifying the controlling chemical mechanisms in effecting ignition, on the relative importance of external versus viscous heating as the dominant ignition source, on the roles of thermal versus kinetic-induced ignition in which heat release and hence nonlinear thermal feedback are not needed in initiating system runaway, and on the consequences of imposing the conventional constant property assumptions in analytical studies. Results show that the state of the hydrogen/oxygen second explosion limit has the dominant influence in the system response in that, for all practical purposes, ignition is not possible when the air-stream temperature is lower than the crossover temperature, even allowing for viscous heating. On the other hand, when the air-stream temperature is higher than the crossover temperature, the predicted ignition distance indicates that ignition is feasible within practical supersonic combustion engines. Furthermore, for the latter situations, the ignition event is initiated by radical proliferation and hence runaway instead of thermal runaway. Finally, it is shown that, while the present computed results qualitatively agree well with those from the asymptotic analysis with reduced mechanisms, the analytically predicted ignition distances are much shorter than the computed values because the analysis has overemphasized the viscous effect through the constant Chapman-Rubesin parameter {rho}{mu} and unity Prandtl number assumptions.

  2. Synthesis of deuterium-labelled 5'-O-[N-(Salicyl)sulfamoyl]adenosine (Sal-AMS-d(4)) as an internal standard for quantitation of Sal-AMS.

    PubMed

    Gupte, Amol; Subramanian, Murali; Remmel, Rory P; Aldrich, Courtney C

    2008-02-01

    5'-O-[N-(Salicyl)sulfamoyl]adenosine (Sal-AMS, 1) is a potent inhibitor of the bifunctional enzyme salicyl-AMP ligase in Mycobacterium tuberculosis. This inhibitor acts by disrupting the biosynthesis of the mycobactin siderophores that are essential for the process of iron acquisition. To aid with in vitro metabolism and in vivo pharmacokinetic studies of Sal-AMS, a stable deuterium-labelled Sal-AMS analog (Sal-AMS-d(4)) was synthesized. This deuterium-labelled analog was used as an internal standard to conduct in vitro plasma and microsomal stability studies. Sal-AMS was found to be stable for 24 h in human plasma and 1 h in human liver microsomes at 37 degrees C.

  3. Comparison of Numerical Models for Vibro-Acoustic Analysis of Structural Panels in Low Modal Density Range Engaging Air Layers

    NASA Astrophysics Data System (ADS)

    Chimeno-Manguan, M.; Martinz-Calvo, B.; Roibas-Millan, E.; Fajardo, P.; Simon, F.; Lopez-Diez, J.

    2012-07-01

    During launch, satellite and their equipment are subjected to loads of random nature and with a wide frequency range. Their vibro-acoustic response is an important issue to be analysed, for example for folded solar arrays and antennas. The main issue at low modal density is the modelling combinations engaging air layers, structures and external fluid. Depending on the modal density different methodologies, as FEM, BEM and SEA should be considered. This work focuses on the analysis of different combinations of the methodologies previously stated used in order to characterise the vibro-acoustic response of two rectangular sandwich structure panels isolated and engaging an air layer between them under a diffuse acoustic field. Focusing on the modelling of air layers, different models are proposed. To illustrate the phenomenology described and studied, experimental results from an acoustic test on an ARA-MKIII solar array in folded configuration are presented along with numerical results.

  4. Nanosecond-pulsed plasma actuation in quiescent air and laminar boundary layer

    NASA Astrophysics Data System (ADS)

    Correale, G.; Michelis, T.; Ragni, D.; Kotsonis, M.; Scarano, F.

    2014-03-01

    An experimental investigation of the working principles of a nanosecond-pulsed dielectric barrier discharge (ns-DBD) plasma actuator has been conducted. Special emphasis is given on the thermal effects accompanying the rapid deposition of energy associated with this kind of actuation. A ns-DBD plasma actuator has been operated in quiescent air conditions as well as in a flat plate laminar boundary layer, with external flow velocity of 5 and 10 m s-1. Schlieren imaging and particle image velocimetry have been used to characterize the actuation. Additionally, the back-current shunt technique has been used for current measurements, from which energy input (per pulse) is calculated. Cases of 10-, 20- and 50-pulse bursts are tested. Schlieren imaging in still air conditions shows the formation of a high-temperature region in the vicinity of the discharge volume. The spatial extent of the visible ‘hot spot’ depends upon the number of pulses within the burst, following a power law. Schlieren imaging of the span-wise effect of the plasma actuator reveals weak compression waves originating from the loci of discharge filaments. The thermal ‘hot spots’ exhibit significant three-dimensionality. Particle image velocimetry is used to measure the velocity field resulting from the ns-DBDs acting on a laminar boundary layer. The disturbance leads to formation of a Tollmien-Schlichting wave train, with spectral content in good agreement with linear stability theory. It is observed that the group length of the wave train is proportional to the number of pulses within the burst.

  5. Fundamental Study of Direct Contact Cold Energy Release by Flowing Hot Air through Ice Particles Packed Layer

    NASA Astrophysics Data System (ADS)

    Aoyama, Sigeo; Inaba, Hideo

    This paper has dealt with the direct contact heat exchange characteristics between ice particles (average ice particle diameter : 3.10mm) packed in the rectangular cold energy storage vessel and flowing hot air as a heat transfer medium. The hot air bubbles ascended in the fluidized ice particles layer, and they were cooled down directly by melting ice particles. The temperature efficiency increased as Reynolds number Re increased because the hot air flowing in the layer became active. The dehumidity efficiency increased with an increase in modified Stefan number and Re, since the heat capacity of inlet air and heat transfer coefficient increased. Finally, some empirical correlations for temperature efficiency, dehumidity efficiency and the completion time of cold energy release were derived in terms of various nondimensional parameters.

  6. Turbulent Boundary Layer on a Finely Perforated Surface Under Conditions of Air Injection at the Expense of External Flow Resources

    NASA Astrophysics Data System (ADS)

    Kornilov, V. I.; Boiko, A. V.; Kavun, I. N.

    2015-11-01

    The characteristics of an incompressible turbulent boundary layer on a flat plate with air blown in though a finely perforated surface from an external confined flow through an input device, located on the "idle" side of the plate, have been investigated experimentally and numerically. A stable decrease in the local values of the coefficient of surface friction along the plate length that attains 85% at the end of the perforated portion is shown. The experimental and calculated data obtained point to the possibility of modeling, under earth conditions, the process of controlling a turbulent boundary layer with air injection by using the resources of an external confined flow.

  7. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  8. Climatology of wintertime long-distance transport of surface-layer air masses arriving urban Beijing in 2001-2012

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xiang-De, XU

    2017-02-01

    In this study, the FLEXPART-WRF coupled modeling system is used to conduct 12-year Lagrangian modeling over Beijing, China, for the winters of 2001-2012. Based on large trajectory tracking ensembles, the long-range air transport properties, in terms of geographic source regions within the atmospheric planetary boundary layer (PBL) and large-scale ventilation, and its association with air quality levels were quantified from a climatological perspective. The results show the following: (1) The air masses residing in the near-surface layer over Beijing potentially originate from broader atmospheric boundary-layer regions, which cover vast areas with the backward tracking time elapsed. However, atmospheric transport from northeastern China and, to a lesser extent, from the surrounding regions of Beijing is important. (2) The evolution of air quality over Beijing is negatively correlated with large-scale ventilation conditions, particularly at a synoptic timescale. Thus, the simple but robust backward-trajectory ventilation (BV) index defined in this study could facilitate operational forecasting of severe air pollution events. (3) By comparison, the relatively short-range transport occurring over transport timescales of less than 3 days from southern and southeastern Beijing and its surrounding areas plays a vital role in the formation of severe air pollution events during the wintertime. (4) Additionally, an interannual trend analysis suggests that the geographic sources and ventilation conditions also changed, at least over the last decade, corresponding to the strength variability of the winter East Asian monsoon.

  9. 30-year lidar observations of the stratospheric aerosol layer state over Tomsk (Western Siberia, Russia)

    NASA Astrophysics Data System (ADS)

    Zuev, Vladimir V.; Burlakov, Vladimir D.; Nevzorov, Aleksei V.; Pravdin, Vladimir L.; Savelieva, Ekaterina S.; Gerasimov, Vladislav V.

    2017-02-01

    There are only four lidar stations in the world which have almost continuously performed observations of the stratospheric aerosol layer (SAL) state over the last 30 years. The longest time series of the SAL lidar measurements have been accumulated at the Mauna Loa Observatory (Hawaii) since 1973, the NASA Langley Research Center (Hampton, Virginia) since 1974, and Garmisch-Partenkirchen (Germany) since 1976. The fourth lidar station we present started to perform routine observations of the SAL parameters in Tomsk (56.48° N, 85.05° E, Western Siberia, Russia) in 1986. In this paper, we mainly focus on and discuss the stratospheric background period from 2000 to 2005 and the causes of the SAL perturbations over Tomsk in the 2006-2015 period. During the last decade, volcanic aerosol plumes from tropical Mt. Manam, Soufrière Hills, Rabaul, Merapi, Nabro, and Kelut and extratropical (northern) Mt. Okmok, Kasatochi, Redoubt, Sarychev Peak, Eyjafjallajökull, and Grímsvötn were detected in the stratosphere over Tomsk. When it was possible, we used the NOAA HYSPLIT trajectory model to assign aerosol layers observed over Tomsk to the corresponding volcanic eruptions. The trajectory analysis highlighted some surprising results. For example, in the cases of the Okmok, Kasatochi, and Eyjafjallajökull eruptions, the HYSPLIT air mass backward trajectories, started from altitudes of aerosol layers detected over Tomsk with a lidar, passed over these volcanoes on their eruption days at altitudes higher than the maximum plume altitudes given by the Smithsonian Institution Global Volcanism Program. An explanation of these facts is suggested. The role of both tropical and northern volcanic eruptions in volcanogenic aerosol loading of the midlatitude stratosphere is also discussed. In addition to volcanoes, we considered other possible causes of the SAL perturbations over Tomsk, i.e., the polar stratospheric cloud (PSC) events and smoke plumes from strong forest fires. At least

  10. Measurement of the air gap width between double-deck metal layers based on surface plasmon resonance

    NASA Astrophysics Data System (ADS)

    Wu, Pao-Tung; Wu, Meng-Chyi; Wu, Chien-Ming

    2010-04-01

    In this article, we verify that the traditional Kretschmann-Raether configuration of surface plasmon resonance (SPR) could be used to measure the air gap width between a gold-plated prism and another gold-plated glass slide. Due to the presence of double-deck metal layers, the Fabry-Perot resonance and surface plasmon tunnel-coupled effects could occur, which would cause the SPR angle to begin to shift at a larger air gap width of about 700 nm as compared to the case of single metal layer with an air gap width of about 350 nm. The simulated results reveal that the SPR angle begins monotonically to shift initially from 44.5° to 46° when the air gap width between double-deck metal layers decreases from 700 to 500 nm. The smallest air gap width is measured to be 539 nm, in which the SPR angle is 45.5°, by fitting the simulated curves to the experimental results.

  11. On Modeling Air/Space-Borne Radar Returns in the Melting Layer

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert

    2005-01-01

    The bright band is the enhanced radar echo associated with the melting of hydrometeors in stratiform rain where the melting process usually occurs below 0 C isotherm over a distance of about 500m. To simulate this radar signature, a scattering model of melting snow is proposed in which the fractional water content is prescribed as a function of the radius of a spherical mixed- phase particle consisting of air, ice and water. The model is based on the observation that melting starts at the surface of the particle and then gradually develops towards the center. To compute the scattering parameters of a non-uniform melting particle, the particle is modeled as a sphere represented by a collection of 64(exp 3) cubic cells of identical size where the probability of water at any cell is prescribed as a function of the radius. The internal field of the particle, used for deriving the effective dielectric constant, is computed by the Conjugate Gradient and Fast Fourier Transform (CGFFT) numerical methods. To make computations of the scattering parameters more efficient, a multi-layer stratified-sphere scattering model is introduced after demonstrating that the scattering parameters of the non-uniformly melting particle can be accurately reproduced by the stratified sphere. In conjunction with a melting layer model that describes the melting fractions and fall velocities of hydrometeors as a function of the distance from the 0 C isotherm, the stratified-sphere model is used to simulate the radar bright band profiles. These simulated profiles are shown to compare well with measurements from the Precipitation Radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite and a dual-wavelength airborne radar. The results suggest that the proposed model of a melting snow particle may be useful in studying the characteristics of the bright-band in particular and mixed- phase hydrometeors in general.

  12. SalSA: A Teraton UHE Neutrino Detector

    NASA Astrophysics Data System (ADS)

    Reil, Kevin

    2006-07-01

    The observed spectrum of ultra-high energy cosmic rays virtually guarantees the presence of ultra-high energy neutrinos due to their interaction with the cosmic microwave background. Unlike cosmic rays, each of these neutrinos will point back directly to its source and will arrive at the Earth unattenuated, from sources perhaps as distant as z = 20. The neutrino telescopes currently under construction, should discover a handful of these events, probably too few for detailed study. This paper describes how an array of VHF and UHF antennas embedded in a large salt dome, SalSA (Salt dome Shower Array) promises to yield a teraton detector (> 500 km3 sr) for contained neutrino events with energies above 1017 eV. Our simulations show that such a detector may observe several hundreds of these neutrinos over its lifetime with excellent angular resolution providing source locations.

  13. SAL: a language for developing an agent-based architecture for mobile robots

    NASA Astrophysics Data System (ADS)

    Lim, Willie Y.; Verzulli, Joe

    1993-05-01

    SAL (the SmartyCat Agent Language) is a language being developed for programming SmartyCat, our mobile robot. SmartyCat's underlying software architecture is agent-based. At the lowest level, the robot sensors and actuators are controlled by agents (viz., the sensing and acting agents, respectively). SAL provides the constructs for organizing these agents into many structures. In particular, SAL supports the subsumption architecture approach. At higher levels of abstraction, SAL can be used for writing programs based on Minsky's Society of Mind paradigm. Structurally, a SAL program is a graph, where the nodes are software modules called agents, and the arcs represent abstract communication links between agents. In SAL, an agent is a CLOS object with input and output ports. Input ports are used for presenting data from the outside world (i.e., other agents) to the agent. Data are presented to the outside world by the agent through its output ports. The main body of the SAL code for the agent specifies the computation or the action performed by the agent. This paper describes how SAL is being used for implementing the agent-based SmartyCat software architecture on a Cybermotion K2A platform.

  14. 75 FR 62364 - Manti-La Sal National Forest Resource Advisory Committee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-08

    ...] [FR Doc No: 2010-25394] DEPARTMENT OF AGRICULTURE Forest Service Manti-La Sal National Forest Resource Advisory Committee; Meeting AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Manti-La... Fillmore, Manti- La Sal National Forest, 599 West Price River Drive, Price, UT 84501. Comments may also...

  15. Diurnal radon variations in the upper soil layers and at the soil-air interface related to meteorological parameters.

    PubMed

    Schubert, M; Schulz, H

    2002-07-01

    Measurements of the radon concentration in a column (1 m2 x 2 m) consisting of a homogeneous mixture of dry sand and uranium tailings have been performed to obtain information on the radon transport under well defined conditions. The dependence of the radon concentration has been exclusively studied on the soil/air temperature gradient and on the wind speed. The soil moisture content has been kept constant. Significant diurnal variations of the radon concentration were detected in the uppermost soil layer and at the soil/air interface. Such a behavior was not found in 30 cm and deeper soil layers. It is argued that the diurnal radon variation in the uppermost soil layer is mainly associated with the diurnal inversion of the soil/air temperature gradient giving rise to a convective soil gas migration additional to the common upward diffusion processes, whereas the diurnal variation of the radon concentration at the soil/air interface is caused by the interplay of the temperature gradient and the wind speed. No impact of atmospheric pressure variations on the radon migration has been observed.

  16. A novel method for air drying aloe leaf slices by covering with filter papers as a shrink-proof layer.

    PubMed

    Kim, S A; Baek, J H; Lee, S J; Choi, S Y; Hur, W; Lee, S Y

    2009-01-01

    To prevent the shrinkage of aloe vera slices during air drying, a method utilizing a shrink-proof layer was developed. The sample was configured of whole leaf aloe slices, where 1 side or both sides were covered with filter papers as shrink-proof layers. After air drying by varying the air temperature and the slice thickness, the drying characteristics, as well as several quality factors of the dried aloe vera leaf slices, were analyzed. In the simulation of the drying curves, the modified Page model showed the best fitness, representing a diffusion-controlled drying mechanism. Nonetheless, there was a trace of a constant-rate drying period in the samples dried by the method. Shrinkage was greatly reduced, and the rehydration ratios increased by approximately 50%. Scanning electron microscopic analysis revealed that the surface structure of original fibrous form was well sustained. FT-IR characteristics showed that the dried samples could sustain aloe polysaccharide acetylation. Furthermore, the functional properties of the dried slices including water holding capacity, swelling, and fat absorption capability were improved, and polysaccharide retention levels increased by 20% to 30%. Therefore, we concluded that application of shrink-proof layers on aloe slices provides a novel way to overcome the shrinkage problems commonly found in air drying, thereby improving their functional properties with less cost. Practical Application: This research article demonstrates a novel air drying method using shrink-proof layers to prevent the shrinkage of aloe slices. We analyzed extensively the characteristics of shrinkage mechanism and physical properties of aloe flesh gels in this drying system. We concluded that this method can be a beneficial means to retain the functional properties of dried aloe, and a potential alternative to freeze drying, which is still costly.

  17. Analysis of sterol and other components present in unsaponifiable matters of mahua, sal and mango kernel oil.

    PubMed

    Dhara, Rupali; Bhattacharyya, Dipak K; Ghosh, Mahua

    2010-01-01

    The amount and characterization of phytosterol and other minor components present in three Indian minor seed oils, mahua (Madhuca latifolia), sal (Shorea robusta) and mango kernel (Mangifera indica), have been done. Theses oils have shown commercial importance as cocoa-butter substitutes because of their high symmetrical triglycerides content. The conventional thin layer chromatography (TLC), gas chromatography (GC) & gas chromatography-mass spectroscopy (GC-MS) techniques were used to characterize the components and the high performance thin layer chromatography (HPTLC) technique was used to quantify the each group of components. The experimental data showed that the all the three oils are rich in sterol content and among all the sterols, beta-sitosterol occupies the highest amount. Sal oil contains appreciable amount of cardenolides, gitoxigenin. Tocopherol is present only in mahua oil and oleyl alcohol is present in mango kernel oil. Hydrocarbon, squalene, is present in all the three oils. The characterization of these minor components will help to detect the presence of the particular oil in specific formulations and to assess its stability as well as nutritional quality of the specific oil.

  18. Boundary-Layer Development and Low-level Baroclinicity during High-Latitude Cold-Air Outbreaks: A Simple Model

    NASA Astrophysics Data System (ADS)

    Chechin, Dmitry G.; Lüpkes, Christof

    2017-01-01

    A new quasi-analytical mixed-layer model is formulated describing the evolution of the convective atmospheric boundary layer (ABL) during cold-air outbreaks (CAO) over polar oceans downstream of the marginal sea-ice zones. The new model is superior to previous ones since it predicts not only temperature and mixed-layer height but also the height-averaged horizontal wind components. Results of the mixed-layer model are compared with dropsonde and aircraft observations carried out during several CAOs over the Fram Strait and also with results of a 3D non-hydrostatic (NH3D) model. It is shown that the mixed-layer model reproduces well the observed ABL height, temperature, low-level baroclinicity and its influence on the ABL wind speed. The mixed-layer model underestimates the observed ABL temperature only by about 10 %, most likely due to the neglect of condensation and subsidence. The comparison of the mixed-layer and NH3D model results shows good agreement with respect to wind speed including the formation of wind-speed maxima close to the ice edge. It is concluded that baroclinicity within the ABL governs the structure of the wind field while the baroclinicity above the ABL is important in reproducing the wind speed. It is shown that the baroclinicity in the ABL is strongest close to the ice edge and slowly decays further downwind. Analytical solutions demonstrate that the e-folding distance of this decay is the same as for the decay of the difference between the surface temperature of open water and of the mixed-layer temperature. This distance characterizing cold-air mass transformation ranges from 450 to 850 km for high-latitude CAOs.

  19. A novel Whole Air Sample Profiler (WASP) for the quantification of volatile organic compounds in the boundary layer

    SciTech Connect

    Mak, J. E.; Su, L.; Guenther, Alex B.; Karl, Thomas G.

    2013-10-16

    The emission and fate of reactive VOCs is of inherent interest to those studying chemical biosphere-atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary 5 layer has limited the data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is the important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/800 OD tube 150m in length. The inlet ram air pressure is used to flow sampled air through the 10 tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect 15 from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  20. The Impact of the Ocean Thermal Skin Layer on Air-Sea Interfacial Heat Fluxes

    NASA Astrophysics Data System (ADS)

    Minnett, P. J.; Wong, E.

    2015-12-01

    The upper ocean heat content has been observed to be increasing over the past few decades much of which has been attributed to anthropogenic effects resulting in an increase in greenhouse gases thereby increasing the amounts of incoming longwave (LWin) radiation impinging onto the ocean's surface. However, the penetration depth of LWin extends to micrometer scales, where the ocean's thermal skin layer (TSL) exists, and does not directly heat the upper few meters of the ocean thereby raising the conundrum of how does the upper ocean warm with increasing levels of infrared (IR) radiation. The TSL consists of a strong temperature gradient on the aqueous side of the interface that sustains the upward heat flux by molecular conduction. As such, we hypothesize the heat lost through the air-sea interface which is controlled by the TSL, modulates the amount of heat stored in the upper few meters of the ocean. An analysis of properties of the retrieved TSL profiles from a shipboard IR spectrometer with heat fluxes (specifically LWin) and wind speeds from two cruises limited to night-time data are presented. We also show a comparison between these properties with current published viscous layer models. The results indicate that the data have an inherent wind speed dependence with net flux thereby requiring a segregation of the data into wind speed bins to acknowledge the effects of wind-driven shear in the analysis. The temperature differences derived from the models indicates that at low wind speeds (<2 m/s), where wind-driven shear effects are negligible and buoyancy effects dominate, the TSL profile's gradient is decreasing with increased LWin which leads to a lowered net heat flux and is in agreement with our hypothesis. However our field results show an opposite effect (higher gradient at higher LWin) which is believed to be due to the formation of a thicker TSL at low winds. The presence of a thicker TSL suggests that more of the vertical temperature gradient lies

  1. Layer thinning and etching of mechanically exfoliated MoS2 nanosheets by thermal annealing in air.

    PubMed

    Wu, Jumiati; Li, Hai; Yin, Zongyou; Li, Hong; Liu, Juqing; Cao, Xiehong; Zhang, Qing; Zhang, Hua

    2013-10-11

    A simple thermal annealing method for layer thinning and etching of mechanically exfoliated MoS2 nanosheets in air is reported. Using this method, single-layer (1L) MoS2 nanosheets are achieved after the thinning of MoS2 nanosheets from double-layer (2L) to quadri-layer (4L) at 330 °C. The as-prepared 1L MoS2 nanosheet shows comparable optical and electrical properties with the mechanically exfoliated, pristine one. In addition, for the first time, the MoS2 mesh with high-density of triangular pits is also fabricated at 330 °C, which might arise from the anisotropic etching of the active MoS2 edge sites. As a result of thermal annealing in air, the thinning of MoS2 nanosheet is possible due to its oxidation to form MoO3 . Importantly, the MoO3 fragments on the top of thinned MoS2 layer induces the hole injection, resulting in the p-type channel in fabricated field-effect transistors.

  2. Vertical structure of boundary layer convection during cold-air outbreaks at Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Wang, Yonggang; Geerts, Bart; Chen, Yaosheng

    2016-01-01

    Boundary layer convection (BLC) is common over high-latitude oceans and adjacent coastal regions when a cold airmass becomes exposed to a sufficient fetch of open water. The vertical structure of mixed-phase BLC clouds and precipitation is examined using the Atmospheric Radiation Measurement Program data set collected at the North Slope of Alaska (NSA) site at Barrow, Alaska. BLC may occur at this location in autumn, when cold air masses originating at higher latitudes advect southward over the still ice-free coastal waters north of Alaska. This study identifies such BLC and documents its occurrence and characteristics. Instruments used for this study include profiling Ka band radars, a depolarization backscatter profiling lidar, a scanning X band radar, a microwave radiometer, a ceilometer, surface meteorological probes, and radiosondes. Six criteria are applied to objectively identify the BLC events, using data collected between 2004 and 2013. BLC episodes are relatively common at the NSA site, but almost exclusively in the month of October, and most episodes are relatively short, less than 10 h in duration. Liquid water is commonly found in these mixed-phase BLC clouds, with a typical liquid water path of 150 g/m2, and snowfall rates average ~3 mm h-1 (water equivalent), in some cases over 10 mm h-1, notwithstanding the low cloud echo tops (~1.0-1.5 km). In one rather weak but persistent episode fall speed estimates derived from the profiling Ka band radar indicates the presence of rimed particles, confirming the convective nature of this precipitation.

  3. Reference dosimetry at the Australian Synchrotron's imaging and medical beamline using free-air ionization chamber measurements and theoretical predictions of air kerma rate and half value layer

    SciTech Connect

    Crosbie, Jeffrey C.; Rogers, Peter A. W.; Stevenson, Andrew W.; Hall, Christopher J.; Lye, Jessica E.; Nordstroem, Terese; Midgley, Stewart M.; Lewis, Robert A.

    2013-06-15

    Purpose: Novel, preclinical radiotherapy modalities are being developed at synchrotrons around the world, most notably stereotactic synchrotron radiation therapy and microbeam radiotherapy at the European Synchrotron Radiation Facility in Grenoble, France. The imaging and medical beamline (IMBL) at the Australian Synchrotron has recently become available for preclinical radiotherapy and imaging research with clinical trials, a distinct possibility in the coming years. The aim of this present study was to accurately characterize the synchrotron-generated x-ray beam for the purposes of air kerma-based absolute dosimetry. Methods: The authors used a theoretical model of the energy spectrum from the wiggler source and validated this model by comparing the transmission through copper absorbers (0.1-3.0 mm) against real measurements conducted at the beamline. The authors used a low energy free air ionization chamber (LEFAC) from the Australian Radiation Protection and Nuclear Safety Agency and a commercially available free air chamber (ADC-105) for the measurements. The dimensions of these two chambers are different from one another requiring careful consideration of correction factors. Results: Measured and calculated half value layer (HVL) and air kerma rates differed by less than 3% for the LEFAC when the ion chamber readings were corrected for electron energy loss and ion recombination. The agreement between measured and predicted air kerma rates was less satisfactory for the ADC-105 chamber, however. The LEFAC and ADC measurements produced a first half value layer of 0.405 {+-} 0.015 and 0.412 {+-} 0.016 mm Cu, respectively, compared to the theoretical prediction of 0.427 {+-} 0.012 mm Cu. The theoretical model based upon a spectrum calculator derived a mean beam energy of 61.4 keV with a first half value layer of approximately 30 mm in water. Conclusions: The authors showed in this study their ability to verify the predicted air kerma rate and x-ray attenuation

  4. High-Reynolds-number turbulent-boundary-layer wall pressure fluctuations with skin-friction reduction by air injection.

    PubMed

    Winkel, Eric S; Elbing, Brian R; Ceccio, Steven L; Perlin, Marc; Dowling, David R

    2008-05-01

    The hydrodynamic pressure fluctuations that occur on the solid surface beneath a turbulent boundary layer are a common source of flow noise. This paper reports multipoint surface pressure fluctuation measurements in water beneath a high-Reynolds-number turbulent boundary layer with wall injection of air to reduce skin-friction drag. The experiments were conducted in the U.S. Navy's Large Cavitation Channel on a 12.9-m-long, 3.05-m-wide hydrodynamically smooth flat plate at freestream speeds up to 20 ms and downstream-distance-based Reynolds numbers exceeding 200 x 10(6). Air was injected from one of two spanwise slots through flush-mounted porous stainless steel frits (approximately 40 microm mean pore diameter) at volume flow rates from 17.8 to 142.5 l/s per meter span. The two injectors were located 1.32 and 9.78 m from the model's leading edge and spanned the center 87% of the test model. Surface pressure measurements were made with 16 flush-mounted transducers in an "L-shaped" array located 10.7 m from the plate's leading edge. When compared to no-injection conditions, the observed wall-pressure variance was reduced by as much as 87% with air injection. In addition, air injection altered the inferred convection speed of pressure fluctuation sources and the streamwise coherence of pressure fluctuations.

  5. Towards Understanding ER Fluids Using Sals/rheometry

    NASA Astrophysics Data System (ADS)

    Crosby, Bryan J.; McLeish, Tom; Block, Harry

    This paper details work in Cranfield and Leeds Universities of making a stock of transparent ER fluids, which could later be utilised in a new optical electro rheometer (OER) to be assembled at Leeds University. Two basic routes were attempted. One was to use glass microspheres and the other was to use polymer spheres. In order to increase the strength of the ER effect, it was necessary to increase the volume loading while still maintaining sufficient transmission (about 75% over 2 mm). It was found to be possible to increase the ER effect quite substantially in some instances, and in others it was possible to get a near perfect refractive index match. It was not possible to combine both requirements in one fluid such that a high static yield stress was apparent in a transparent ER fluid. However one fluid was made which gave acceptable diffraction losses at high volume fractions, remained in suspension for extended periods and provide about 700 Pa yield stress at 4kV/mm and about 30% volume fraction viz: untreated poly(ethylene vinyl acetate) microspheres in Cereclor/bromonaphthalene/polystyrene solution. The OER being assembled at Leeds University is intended to record small angle light scattering (SALS) profiles, electrical and mechanical properties of ER fluids simultaneously. The OER is based around a DSR 500 machine purchased from Rheometric Scientific with quartz tools coated with transparent indium tin oxide(ITO), which is capable of measuring both steady state (DC) and oscillatory (AC) material parameters.

  6. Tsunami hazard assessment in the coastal area of Rabat and Salé, Morocco

    NASA Astrophysics Data System (ADS)

    Renou, C.; Lesne, O.; Mangin, A.; Rouffi, F.; Atillah, A.; El Hadani, D.; Moudni, H.

    2011-08-01

    In the framework of the three-year SCHEMA European project (www.schemaproject.org), we present a generic methodology developed to produce tsunami building vulnerability and impact maps. We apply this methodology to the Moroccan coast. This study focuses on the Bouregreg Valley which is at the junction between Rabat (administrative capital), and Salé. Both present large populations and new infrastructure development. Using a combination of numerical modelling, field surveys, Earth Observation and GIS data, the risk has been evaluated for this vulnerable area. Two tsunami scenarios were studied to estimate a realistic range of hazards on this coast: a worst-case scenario based on the historical Lisbon earthquake of 1755 and a moderate scenario based on the Horseshoe earthquake of 28 February 1969. For each scenario, numerical models allowed the production of tsunami hazard maps (maximum inundation extent and maximum inundation depths). Moreover, the modelling results of these two scenarios were compared with the historical data available. A companion paper to this article (Atillah et al., 2011) presents the following steps of the methodology, namely the elaboration of building damage maps by crossing layers of building vulnerability and the so-inferred inundation depths.

  7. Mitigating methane emissions and air intrusion in heterogeneous landfills with a high permeability layer.

    PubMed

    Jung, Yoojin; Imhoff, Paul T; Augenstein, Don; Yazdani, Ramin

    2011-05-01

    Spatially variable refuse gas permeability and landfill gas (LFG) generation rate, cracking of the soil cover, and reduced refuse gas permeability because of liquid addition can all affect CH(4) collection efficiency when intermediate landfill covers are installed. A new gas collection system that includes a near-surface high permeability layer beneath the landfill cover was evaluated for enhancing capture of LFG and mitigating CH(4) emissions. Simulations of gas transport in two-dimensional domains demonstrated that the permeable layer reduces CH(4) emissions up to a factor of 2 for particular spatially variable gas permeability fields. When individual macrocracks formed in the cover soil and the permeable layer was absent, CH(4) emissions increased to as much as 24% of the total CH(4) generated, double the emissions when the permeable layer was installed. CH(4) oxidation in the cover soil was also much more uniform when the permeable layer was present: local percentages of CH(4) oxidized varied between 94% and 100% across the soil cover with the permeable layer, but ranged from 10% to 100% without this layer for some test cases. However, the permeable layer had a minor effect on CH(4) emissions and CH(4) oxidation in the cover soil when the ratio of the gas permeability of the cover soil to the mean refuse gas permeability ≤ 0.05. The modeling approach employed in this study may be used to assess the utility of other LFG collection systems and management practices.

  8. Biochemical Activities of the Wiskott-Aldrich Syndrome Homology Region 2 Domains of Sarcomere Length Short (SALS) Protein.

    PubMed

    Tóth, Mónika Ágnes; Majoros, Andrea Kinga; Vig, Andrea Teréz; Migh, Ede; Nyitrai, Miklós; Mihály, József; Bugyi, Beáta

    2016-01-08

    Drosophila melanogaster sarcomere length short (SALS) is a recently identified Wiskott-Aldrich syndrome protein homology 2 (WH2) domain protein involved in skeletal muscle thin filament regulation. SALS was shown to be important for the establishment of the proper length and organization of sarcomeric actin filaments. Here, we present the first detailed characterization of the biochemical activities of the tandem WH2 domains of SALS (SALS-WH2). Our results revealed that SALS-WH2 binds both monomeric and filamentous actin and shifts the monomer-filament equilibrium toward the monomeric actin. In addition, SALS-WH2 can bind to but fails to depolymerize phalloidin- or jasplakinolide-bound actin filaments. These interactions endow SALS-WH2 with the following two major activities in the regulation of actin dynamics: SALS-WH2 sequesters actin monomers into non-polymerizable complexes and enhances actin filament disassembly by severing, which is modulated by tropomyosin. We also show that profilin does not influence the activities of the WH2 domains of SALS in actin dynamics. In conclusion, the tandem WH2 domains of SALS are multifunctional regulators of actin dynamics. Our findings suggest that the activities of the WH2 domains do not reconstitute the presumed biological function of the full-length protein. Consequently, the interactions of the WH2 domains of SALS with actin must be tuned in the cellular context by other modules of the protein and/or sarcomeric components for its proper functioning.

  9. Salvinorin B derivatives, EOM-Sal B and MOM-Sal B, produce stimulus generalization in male Sprague-Dawley rats trained to discriminate salvinorin A.

    PubMed

    Peet, Mary Melissa; Baker, Lisa E

    2011-09-01

    Salvinorin A, the main active component of Salvia divinorum, is a potent and selective κ opioid receptor agonist. Synthetic derivatives of this substance may be useful in the development of medicinal treatments for pain, mood disorders, and drug dependence. Such developments require extensive preclinical screening of these compounds. The drug discrimination assay is a valuable method for exploring potential similarities between novel compounds and known drugs of abuse with respect to their interoceptive stimulus properties, and can be used to investigate the potency of salvinorin A and its derivatives in vivo. This study used drug discrimination methods to compare two synthetic derivatives of salvinorin B, the ethoxymethyl ether (EOM-Sal B) and methoxymethyl ether (MOM-Sal B) with salvinorin A. Male Sprague-Dawley rats were trained to discriminate 2.0 mg/kg of salvinorin A from its vehicle (75% dimethylsulfoxide/25% water) in a fixed ratio 20 food-reinforced drug discrimination procedure, and were tested for stimulus generalization with EOM-Sal B and MOM-Sal B. For comparison, substitution tests were also conducted with a μ agonist, morphine, a dissociative hallucinogen, ketamine, and two serotonergic hallucinogens, D-lysergic diethylamide (LSD) and 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane. Time-course tests were also conducted with salvinorin A and EOM-Sal B. Both EOM-Sal B and MOM-Sal B substituted fully for salvinorin A and displayed greater potency than salvinorin A. EOM-Sal B was discriminated at longer postinjection intervals than salvinorin A. Morphine and 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane failed to substitute for salvinorin A, although ketamine and LSD produced significant drug-appropriate responding. The current findings are consistent with previous reports that salvinorin A produces detectable stimulus effects that are distinct from those of other drug classes and, for the first time, establish that synthetic derivatives of this

  10. Theoretical and numerical study of air layer drag reduction in two-phase Couette-Poiseuille flow

    NASA Astrophysics Data System (ADS)

    Kim, Dokyun; Moin, Parviz

    2008-11-01

    The objective of the present study is to predict and understand the air layer drag reduction (ALDR) phenomenon. Recent experiments (Elbing et al. 2008) have shown net drag reductions if air is injected beyond a critical rate next to the wall. The analysis is performed on a two-phase Couette-Poiseuille flow configuration, which mimics the far downstream region of boundary layer flow on a flat plate. Both theoretical and numerical approaches are employed to investigate the stability and mechanisms of ALDR. The linear stability of air-liquid interface is investigated by solving the Orr-Sommerfeld equations. From the stability analysis, the stability of the interface is reduced as the liquid free-stream velocity, Froude number and velocity gradients at the interface are increased, while the stability is enhanced as the gas flow rate and surface tension are increased. The Critical gas flow rates from stability theory are compared with experimental results, showing good agreement. Direct numerical simulations with a Refiend Level Set Grid technique has been performed to investigate the evolution of the interface, the turbulence interaction and nonlinear mechanisms of ALDR. It is observed that the Weber number has significant impact on the characteristics of the interface development.

  11. Sum-Frequency Generation Spectroscopy for Studying Organic Layers at Water-Air Interfaces: Microlayer Monitoring and Surface Reactivity

    NASA Astrophysics Data System (ADS)

    Laß, Kristian; Kleber, Joscha; Bange, Hermann; Friedrichs, Gernot

    2015-04-01

    The sea surface microlayer, according to commonly accepted terminology, comprises the topmost millimetre of the oceanic water column. It is often enriched with organic matter and is directly influenced by sunlight exposure and gas exchange with the atmosphere, hence making it a place for active biochemistry and photochemistry as well as for heterogeneous reactions. In addition, surface active material either is formed or accumulates directly at the air-water interface and gives rise to very thin layers, sometimes down to monomolecular thickness. This "sea surface nanolayer" determines the viscoelastic properties of the seawater surface and thus may impact the turbulent air-sea gas exchange rates. To this effect, this small scale layer presumably plays an important role for large scale changes of atmospheric trace gas concentrations (e.g., by modulating the ocean carbon sink characteristics) with possible implications for coupled climate models. To date, detailed knowledge about the composition, structure, and reactivity of the sea surface nanolayer is still scarce. Due to its small vertical dimension and the small amount of material, this surfactant layer is very difficult to separate and analyse. A way out is the application of second-order nonlinear optical methods, which make a direct surface-specific and background-free detection of this interfacial layer possible. In recent years, we have introduced the use of vibrational sum frequency generation (VSFG) spectroscopy to gain insight into natural and artificial organic monolayers at the air-water interface. In this contribution, the application of VSFG spectroscopy for the analysis of the sea surface nanolayer will be illustrated. Resulting spectra are interpreted in terms of layer composition and surfactant classes, in particular with respect to carbohydrate-containing molecules such as glycolipids. The partitioning of the detected surfactants into soluble and non-soluble ("wet" and "dry") surfactants will be

  12. Sensing and signaling of oxidative stress in chloroplasts by inactivation of the SAL1 phosphoadenosine phosphatase

    PubMed Central

    Mabbitt, Peter D.; Phua, Su Yin; Mueller, Jonathan W.; Nisar, Nazia; Gigolashvili, Tamara; Stroeher, Elke; Grassl, Julia; Arlt, Wiebke; Estavillo, Gonzalo M.; Jackson, Colin J.; Pogson, Barry J.

    2016-01-01

    Intracellular signaling during oxidative stress is complex, with organelle-to-nucleus retrograde communication pathways ill-defined or incomplete. Here we identify the 3′-phosphoadenosine 5′-phosphate (PAP) phosphatase SAL1 as a previously unidentified and conserved oxidative stress sensor in plant chloroplasts. Arabidopsis thaliana SAL1 (AtSAL1) senses changes in photosynthetic redox poise, hydrogen peroxide, and superoxide concentrations in chloroplasts via redox regulatory mechanisms. AtSAL1 phosphatase activity is suppressed by dimerization, intramolecular disulfide formation, and glutathionylation, allowing accumulation of its substrate, PAP, a chloroplast stress retrograde signal that regulates expression of plastid redox associated nuclear genes (PRANGs). This redox regulation of SAL1 for activation of chloroplast signaling is conserved in the plant kingdom, and the plant protein has evolved enhanced redox sensitivity compared with its yeast ortholog. Our results indicate that in addition to sulfur metabolism, SAL1 orthologs have evolved secondary functions in oxidative stress sensing in the plant kingdom. PMID:27432987

  13. Air emission into a water shear layer through porous media. Part 1: Scaling of bubble creation noise

    SciTech Connect

    Myer, E.C.; Marboe, R.C.

    1994-12-31

    In many industrial processes, including aeration systems and reduction of cavitation induced vibration and erosion in hydroturbine casings, it is advantageous to be able to create gas bubbles with specific size distributions, higher uniform or widely distributed in diameter, depending on the situation. The induced noise and vibration associated with such systems is of increasing concern due to hearing protection standards and structural fatigue of the casing and piping. A convenient way to generate a two-phase distribution within a water pipe is to span the pipe with a streamlined surface such as a two dimensional hydrofoil and emit air through a porous medium into the shear flow over the hydrofoil. Such a hydrofoil was built and mounted in the ARL Penn state 30.5 cm diameter water tunnel. Air was introduced into a plenum within the hydrofoil which provided air evenly to the entire surface of the centered stainless steel cover plates (20 and 100 micron porosities). Air bubbles formed at the surfaces of the cover plates through the breakdown of small jets of air issuing from the pores. The effects of the air jet size and momentum on the formation noise for a given set of conditions were evaluated by using the two different porosities of sintered metal and through the use of an array of 20, 1.2 mm diameter orifices. A variation in the shear layer was achieved by discharge through plates mounted on either the pressure or suction side of the foil. The noise due to bubble creation and transport through the highly turbulent foil wake was measured by a 2.5 cm diameter hydrophone mounted on the water tunnel window.

  14. Studies of acoustic effects on a flow boundary layer in air

    NASA Technical Reports Server (NTRS)

    Mechel, F.; Schilz, W.

    1986-01-01

    Effects of sound fields on the flow boundary layer on a flat plate subjected to a parallel flow are studied. The boundary layer is influenced by controlling the stagnation point flow at the front edge of the plate. Depending on the Reynolds number and sound frequency, excitation or suppression of turbulent is observed. Measurements were taken at wind velocities between 10 and 30 m/sec and sound frequencies between 0.2 and 3.0 kHz.

  15. Computational Study of Surface Tension and Wall Adhesion Effects on an Oil Film Flow Underneath an Air Boundary Layer

    NASA Technical Reports Server (NTRS)

    Celic, Alan; Zilliac, Gregory G.

    1998-01-01

    The fringe-imaging skin friction (FISF) technique, which was originally developed by D. J. Monson and G. G. Mateer at Ames Research Center and recently extended to 3-D flows, is the most accurate skin friction measurement technique currently available. The principle of this technique is that the skin friction at a point on an aerodynamic surface can be determined by measuring the time-rate-of-change of the thickness of an oil drop placed on the surface under the influence of the external air boundary layer. Lubrication theory is used to relate the oil-patch thickness variation to shear stress. The uncertainty of FISF measurements is estimated to be as low as 4 percent, yet little is known about the effects of surface tension and wall adhesion forces on the measured results. A modified version of the free-surface Navier-Stokes solver RIPPLE, developed at Los Alamos National Laboratories, was used to compute the time development of an oil drop on a surface under a simulated air boundary layer. RIPPLE uses the volume of fluid method to track the surface and the continuum surface force approach to model surface tension and wall adhesion effects. The development of an oil drop, over a time period of approximately 4 seconds, was studied. Under the influence of shear imposed by an air boundary layer, the computed profile of the drop rapidly changes from its initial circular-arc shape to a wedge-like shape. Comparison of the time-varying oil-thickness distributions computed using RIPPLE and also computed using a greatly simplified numerical model of an oil drop equation which does not include surface tension and wall adhesion effects) was used to evaluate the effects of surface tension on FISF measurement results. The effects of surface tension were found to be small but not necessarily negligible in some cases.

  16. Inhibition of microbial growth on air cathodes of single chamber microbial fuel cells by incorporating enrofloxacin into the catalyst layer.

    PubMed

    Liu, Weifeng; Cheng, Shaoan; Sun, Dan; Huang, Haobin; Chen, Jie; Cen, Kefa

    2015-10-15

    The inevitable growth of aerobic bacteria on the surface of air cathodes is an important factor reducing the performance stability of air cathode single-chamber membrane-free microbial fuel cells (MFCs). Thus searching for effective methods to inhibit the cathodic microbial growth is critical for the practical application of MFCs. In this study, enrofloxacin (ENR), a broad spectrum fluoroquinolone antibiotic, was incorporated into the catalyst layer of activated carbon air cathodes (ACACs) to inhibit the cathodic microbial growth. The biomass content on ACACs was substantially reduced by 60.2% with ENR treatment after 91 days of MFCs operation. As a result of the inhibited microbial growth, the oxygen reduction catalytic performance of the ENR treated ACACs was much stable compared to the fast performance decline of the untreated control. Consequently, a quite stable electricity production was obtained for the MFCs with the ENR treated ACACs, in contrast with a 22.5% decrease in maximum power density of the MFCs with the untreated cathode. ENR treatment of ACACs showed minimal effects on the anode performance. These results indicate that incorporating antibiotics into ACACs should be a simple and effective strategy to inhibit the microbial growth and improve the long-term stability of the performance of air cathode and the electricity production of MFCs.

  17. Investigations of the boundary-layer control on a full scale swept wing with air bled off from the turbojet

    NASA Technical Reports Server (NTRS)

    Rebuffet, Pierre; Poisson-Quinton, PH

    1952-01-01

    The following account reviews the various stages of a research program relative to the high-lift devices on a swept wing by combined suction and blowing (jet action), with ejectors fed by air bled off (extracted) from the turbojet. After reviewing the essential principles of the boundary-layer control obtained by comparison with theory, the electric analogies and the wind-tunnel tests as well as the essential elements of ejector operations, the writers describe the tests made in the large tunnel at Chalais-Meudon on a full-scale model of the SO 6020 wing.

  18. Evaluation on the air-borne ultrasound-assisted hot air convection thin-layer drying performance of municipal sewage sludge.

    PubMed

    Sun, G Y; Chen, M Q; Huang, Y W

    2017-01-01

    The thin-layer drying behavior of the municipal sewage sludge in a laboratory-scale hot air forced convective dryer assisted with air-borne ultrasound was investigated in between 70 and 130°C hot air temperatures. The drying kinetics in the convective process alone were compared to that for ultrasound-assist process at three ultrasound powers (30, 90, 150W). The average drying rates within whole drying temperature range at ultrasound powers of 30, 90 and 150W increased by about 22.6%, 27.8% and 32.2% compared with the convective drying alone (without ultrasound). As the temperature increasing from 70°C to 130°C, there were maximum increasing ratios for the effective moisture diffusivities of the sewage sludge in both falling rate periods at ultrasonic power of 30W in comparison with other two high powers. In between the ultrasound powers of 0 and 30W, the effect of the power on the drying rate was significant, while its effect was not obvious over 30W. Therefore, the low ultrasonic power can be just set in the drying process. The values of the apparent activation energy in the first falling rate period were down from 13.52 to 12.78kJmol(-1), and from 17.21 to 15.10kJmol(-1) for the second falling rate period with increasing the ultrasonic power from 30 to 150W. The values of the apparent activation energy in two falling rate periods with the ultrasound-assist were less than that for the hot air convective drying alone.

  19. The influence of equivalence ratio and Soret effect on the ignition of hydrogen-air mixtures in supersonic boundary layers

    SciTech Connect

    Figueira da Silva, L.F.; Deshaies, B.

    1994-12-31

    As a result of viscous heating, spontaneous ignition of a supersonic flow of premixed combustible gases can occur in boundary layers. In a previous numerical study, the main structure of the reacting flow related to this specific type of ignition was given in the case of a laminar boundary layer of hydrogen and air developing over a flat plate. To complete the first mapping of the ignition as a function of the boundary conditions, the authors present in this paper the results of a specific study of the influence of the equivalence ratio of the mixture on ignition. The equivalence ratio is found to modify the chemical induction time in the boundary layer as follows: (1) in a direct way, (2) via the dependence of the wall temperature on the composition. Because of these combined effects, the minimum induction length is obtained for unusually lead mixtures. As it modifies local composition, the Soret effect is also found to change the boundary-layer induction length.

  20. Characterisation of SalRAB a salicylic acid inducible positively regulated efflux system of Rhizobium leguminosarum bv viciae 3841.

    PubMed

    Tett, Adrian J; Karunakaran, Ramakrishnan; Poole, Philip S

    2014-01-01

    Salicylic acid is an important signalling molecule in plant-microbe defence and symbiosis. We analysed the transcriptional responses of the nitrogen fixing plant symbiont, Rhizobium leguminosarum bv viciae 3841 to salicylic acid. Two MFS-type multicomponent efflux systems were induced in response to salicylic acid, rmrAB and the hitherto undescribed system salRAB. Based on sequence similarity salA and salB encode a membrane fusion and inner membrane protein respectively. salAB are positively regulated by the LysR regulator SalR. Disruption of salA significantly increased the sensitivity of the mutant to salicylic acid, while disruption of rmrA did not. A salA/rmrA double mutation did not have increased sensitivity relative to the salA mutant. Pea plants nodulated by salA or rmrA strains did not have altered nodule number or nitrogen fixation rates, consistent with weak expression of salA in the rhizosphere and in nodule bacteria. However, BLAST analysis revealed seventeen putative efflux systems in Rlv3841 and several of these were highly differentially expressed during rhizosphere colonisation, host infection and bacteroid differentiation. This suggests they have an integral role in symbiosis with host plants.

  1. A numerical study of hydrogen-air combustion within a supersonic boundary layer

    SciTech Connect

    Figueira da silva, L.F.; Deshaies, B.; Champion, M. )

    1992-01-01

    A numerical study of the ignition and spread of combustion within a supersonic boundary layer is presented for case where ignition is triggered by viscous dissipation and/or wall temperature effects. Three important regions are found in the boundary layer in the streamwise direction. They are: (1) an induction region where the process is mainly controlled by streamwise convection and chemical kinetics in the presence of transverse molecular transports, (2) a thermal runaway region corresponding to a large chemical heat release, (3) a flame region which develops at the end of the thermal runaway region where a flame is stabilized at the outer edge of the boundary layer. The whole chemical process becomes endothermic for large values of free-stream Mach numbers due to intense dissociation effects. 11 refs.

  2. Air-stable ink for scalable, high-throughput layer deposition

    DOEpatents

    Weil, Benjamin D; Connor, Stephen T; Cui, Yi

    2014-02-11

    A method for producing and depositing air-stable, easily decomposable, vulcanized ink on any of a wide range of substrates is disclosed. The ink enables high-volume production of optoelectronic and/or electronic devices using scalable production methods, such as roll-to-roll transfer, fast rolling processes, and the like.

  3. Entrainment of stratospheric air and Asian pollution by the convective boundary layer in the southwestern U.S.

    NASA Astrophysics Data System (ADS)

    Langford, A. O.; Alvarez, R. J.; Brioude, J.; Fine, R.; Gustin, M. S.; Lin, M. Y.; Marchbanks, R. D.; Pierce, R. B.; Sandberg, S. P.; Senff, C. J.; Weickmann, A. M.; Williams, E. J.

    2017-01-01

    A series of deep stratospheric intrusions in late May 2013 increased the daily maximum 8 h surface ozone (O3) concentrations to more than 70 parts per billion by volume (ppbv) at rural and urban surface monitors in California and Nevada. This influx of ozone-rich lower stratospheric air and entrained Asian pollution persisted for more than 5 days and contributed to exceedances of the 2008 8 h national ambient air quality standard of 75 ppbv on 21 and 25 May in Clark County, NV. Exceedances would also have occurred on 22 and 23 May had the new standard of 70 ppbv been in effect. In this paper, we examine this episode using lidar measurements from a high-elevation site on Angel Peak, NV, and surface measurements from NOAA, the Clark County, Nevada Department of Air Quality, the Environmental Protection Agency Air Quality System, and the Nevada Rural Ozone Initiative. These measurements, together with analyses from the National Centers for Environmental Prediction/North American Regional Reanalysis; NOAA Geophysical Fluid Dynamics Laboratory AM3 model; NOAA National Environmental Satellite, Data, and Information Service Real-time Air Quality Modeling System; and FLEXPART models, show that the exceedances followed entrainment of 20 to 40 ppbv of lower stratospheric ozone mingled with another 0 to 10 ppbv of ozone transported from Asia by the unusually deep convective boundary layers above the Mojave desert. Our analysis suggests that this vigorous mixing can affect both high and low elevations and help explain the springtime ozone maximum in the southwestern U.S.

  4. Karst evolution in the Cordillera de la Sal (Atacama, Chili)

    NASA Astrophysics Data System (ADS)

    de Waele, J.; Forti, P.; Picotti, V.; Zini, L.; Cucchi, F.; Brook, G.

    2009-04-01

    Rock salt composed of halite is at least three orders of magnitude more soluble than limestone. Because of this very high solubility rock salt rarely crops out extensively at the surface and is readily dissolved leaving insoluble residue (mainly clays and marls). Rock salt can only survive at the surface where climate is extremely arid and normally displays a large set of typical solution morphologies similar to those developed on limestone. Solution of rock salt also leads to the formation of underground caves several km long. Close to the village of San Pedro de Atacama, North of the Salar de Atacama basin, there is an important NNE-SSW trending elongated anticlinal ridge composed of Oligo-Miocene evaporitic rocks known under the name Cordillera de la Sal. The thick salt beds of this ridge, even in this hyperarid climate (mean annual rainfall is below 20 mm/y and there may be no rain for several years), have been karstified by occasional rains and have a well developed surface karst geomorphology with extremely sharp rillenkarren often isolating salt pinnacles of up to 15 m in height. During the past 10 years interesting salt caves have been discovered in these halite beds and a detailed morphological study has been carried out both at the surface and in the most important caves with the aim of understanding the mechanisms responsible for their formation and evolution. Sixteen wood and bone fragments from the ceilings of caves and from diamictons in passages have been AMS radiocarbon dated, allowing us to determine when the cave systems formed and when the major sediment units were emplaced. In fact, cave formation appears to have been very rapid, with development of huge cave passages in salt (more than 10 m wide and 30 m high) in less than 2,000 years. Moreover, detailed surveys of cave morphology (e.g. meanders, erosion benches) and sediments (diamictons) suggest that the caves were formed by short-lived flash floods, probably produced by single extreme

  5. Air-coupled ultrasonic investigation of multi-layered composite materials.

    PubMed

    Kazys, R; Demcenko, A; Zukauskas, E; Mazeika, L

    2006-12-22

    Air-coupled ultrasonics is fine alternative for the immersion testing technique. Usually a through transmission and a pitch-catch arrangement of ultrasonic transducers are used. The pitch-catch arrangement is very attractive for non-destructive testing and evaluation of materials, because it allows one-side access to the object. However, this technique has several disadvantages. It is sensitive to specularly reflected and edge waves. A spatial resolution depends on a distance between the transducers. A new method for detection and visualisation of inhomogeneities in composite materials using one-side access air-coupled ultrasonic measurement technique is described. Numerical predictions of Lamb wave interaction with a defect in a composite material are carried out and the interaction mechanism is explained. Experimental measurements are carried out with different arrangements of the transducers. The proposed method enables detect delamination and impact type defects in honeycomb materials.

  6. Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

    SciTech Connect

    Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

    2013-08-16

    Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

  7. Field deployment of thin film passive air samplers for persistent organic pollutants: a study in the urban atmospheric boundary layer.

    PubMed

    Farrar, N J; Harner, T; Shoeib, M; Sweetman, A; Jones, K C

    2005-01-01

    This paper reports on the first field deployment of rapidly equilibrating thin-film passive air samplers under ambient conditions. The POlymer-coated Glass (POG) samplers have a coating of ethylene vinyl acetate (EVA) less than 1 microm thick applied to a glass surface. This can be dissolved off after exposure and prepared for the quantification of persistent organic pollutants (POPs) that have partitioned into the film during field exposure. In this study, POGs were deployed at various heights on the CN Tower in Toronto, Canada, to investigate the vertical distribution of selected compounds (PCBs, PAHs, organochlorine pesticides) in the atmospheric boundary layer of an urban area. The feasibility of the method to detect POPs from a few cubic meters of air was demonstrated, indicating the potential for rapid, low-volume sampling of air for ambient levels of POPs. PAH levels declined sharply with height, confirming ground-level emissions in urban areas as sources of these compounds; PCBs did the same, although less strongly. Different sampling events detected different vertical distributions of OC pesticides which could be related to local or distantsources, and variations in POPs on the samplers in these different events/heights demonstrate the dynamic nature of sources and atmospheric mixing of POPs.

  8. Continuous flow membrane-less air cathode microbial fuel cell with spunbonded olefin diffusion layer.

    PubMed

    Tugtas, Adile Evren; Cavdar, Pelin; Calli, Baris

    2011-11-01

    The power production performance of a membrane-less air-cathode microbial fuel cell was evaluated for 53 days. Anode and cathode electrodes and the micro-fiber cloth separator were configured by sandwiching the separator between two electrodes. In addition, the air-facing side of the cathode was covered with a spunbonded olefin sheet instead of polytetrafluoroethylene (PTFE) coating to control oxygen diffusion and water loss. The configuration resulted in a low resistance of about 4Ω and a maximum power density of 750 mW/m2. However, as a result of a gradual decrease in the cathode potential, maximum power density decreased to 280 mW/m2. The declining power output was attributed to loss of platinum catalyst (8.26%) and biomass growth (38.44%) on the cathode. Coulombic efficiencies over 55% and no water leakage showed that the spunbonded olefin sheet covering the air-facing side of the cathode can be a cost-effective alternative to PTFE coating.

  9. Numerical investigation of the Arctic ice-ocean boundary layer and implications for air-sea gas fluxes

    NASA Astrophysics Data System (ADS)

    Bigdeli, Arash; Loose, Brice; Nguyen, An T.; Cole, Sylvia T.

    2017-01-01

    In ice-covered regions it is challenging to determine constituent budgets - for heat and momentum, but also for biologically and climatically active gases like carbon dioxide and methane. The harsh environment and relative data scarcity make it difficult to characterize even the physical properties of the ocean surface. Here, we sought to evaluate if numerical model output helps us to better estimate the physical forcing that drives the air-sea gas exchange rate (k) in sea ice zones. We used the budget of radioactive 222Rn in the mixed layer to illustrate the effect that sea ice forcing has on gas budgets and air-sea gas exchange. Appropriate constraint of the 222Rn budget requires estimates of sea ice velocity, concentration, mixed-layer depth, and water velocities, as well as their evolution in time and space along the Lagrangian drift track of a mixed-layer water parcel. We used 36, 9 and 2 km horizontal resolution of regional Massachusetts Institute of Technology general circulation model (MITgcm) configuration with fine vertical spacing to evaluate the capability of the model to reproduce these parameters. We then compared the model results to existing field data including satellite, moorings and ice-tethered profilers. We found that mode sea ice coverage agrees with satellite-derived observation 88 to 98 % of the time when averaged over the Beaufort Gyre, and model sea ice speeds have 82 % correlation with observations. The model demonstrated the capacity to capture the broad trends in the mixed layer, although with a significant bias. Model water velocities showed only 29 % correlation with point-wise in situ data. This correlation remained low in all three model resolution simulations and we argued that is largely due to the quality of the input atmospheric forcing. Overall, we found that even the coarse-resolution model can make a modest contribution to gas exchange parameterization, by resolving the time variation of parameters that drive the 222Rn budget

  10. Fulleropyrrolidinium Iodide As an Efficient Electron Transport Layer for Air-Stable Planar Perovskite Solar Cells.

    PubMed

    Huang, Jiabin; Yu, Xuegong; Xie, Jiangsheng; Li, Chang-Zhi; Zhang, Yunhai; Xu, Dikai; Tang, Zeguo; Cui, Can; Yang, Deren

    2016-12-21

    Organic-inorganic halide perovskite solar cells have attracted great attention in recent years. But there are still a lot of unresolved issues related to the perovskite solar cells such as the phenomenon of anomalous hysteresis characteristics and long-term stability of the devices. Here, we developed a simple three-layered efficient perovskite device by replacing the commonly employed PCBM electrical transport layer with an ultrathin fulleropyrrolidinium iodide (C60-bis) in an inverted p-i-n architecture. The devices with an ultrathin C60-bis electronic transport layer yield an average power conversion efficiency of 13.5% and a maximum efficiency of 15.15%. Steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements show that the high performance is attributed to the efficient blocking of holes and high extraction efficiency of electrons by C60-bis, due to a favorable energy level alignment between the CH3NH3PbI3 and the Ag electrodes. The hysteresis effect and stability of our perovskite solar cells with C60-bis become better under indoor humidity conditions.

  11. CALIPSO inferred most probable heights of global dust and smoke layers

    NASA Astrophysics Data System (ADS)

    Huang, Jingfeng; Guo, Jianping; Wang, Fu; Liu, Zhaoyan; Jeong, Myeong-Jae; Yu, Hongbin; Zhang, Zhibo

    2015-05-01

    The vertical location of aerosol layers is critical for determining predominance of aerosol radiative and microphysical effects in aerosol-cloud-precipitation-climate interaction. The spaceborne lidar system, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), provides an unprecedented opportunity to observe vertical distributions of global aerosol layers. In this study we examine the most probable height (MPH) of dust and smoke layers, which are calculated either from aerosol occurrence frequency (OF) in vertical feature mask or aerosol extinction profile. The study focuses on six high-aerosol-loading regions where aerosols are of great interest in a range of scientific topics: Saharan Air Layer (SAL) over Tropical Atlantic, West African Monsoon region (WAM), Southeast Atlantic Ocean (SAO), Southeast Asia (SEA) and South China Sea, Amazon (AMZ), and Northwestern Pacific (NWP). The analysis revealed interesting spatial and seasonal variability of different vertical mixture features over these regions: seasonal migration of dust layers over SAL, separation and mixture of dust and smoke layers over WAM and NWP, and smoke layer above clouds over SAO, SEA, and AMZ. Results also indicated that the OF-based MPH tends to be much higher than the aerosol optical depth (AOD)-based MPH, owing to the predominating near-surface sources. Within the same vertical resolution grid of CALIPSO, aerosols are found with higher OF at higher levels but AOD tends to increase toward lower levels, because most aerosol sources are near the surface and the aerosol layers transported to high altitudes are generally much more diluted over larger spatial domain than those near the surface.

  12. A Long-Lived Tracer Perspective on the Origin of Air in the Tropical Tropopause Layer during ATTREX

    NASA Astrophysics Data System (ADS)

    Hintsa, E. J.; Moore, F.; Dutton, G. S.; Hall, B. D.; Nance, J. D.; Elkins, J. W.; Gao, R.; Rollins, D. W.; Thornberry, T. D.; Watts, L.; Fahey, D. W.; Daube, B. C.; Pittman, J. V.; Wofsy, S. C.; Atlas, E. L.; Navarro, M. A.; Dessler, A. E.; Mahoney, M.

    2013-12-01

    The origin of air in the tropical tropopause layer (TTL) and the subsequent transport pathways of these air masses play a critical role in the delivery of trace gases, including ozone depleting substances and water vapor, to the stratosphere. The Airborne Tropical Tropopause Experiment (ATTREX) is designed to study this transport and processing in the TTL over the Pacific Ocean, including how dehydration occurs in this region and how trace gases involved in ozone depletion and climate reach the tropical lower stratosphere. For this mission, the NASA Global Hawk aircraft is carrying a suite of in situ and remote sensing instruments for trace gases, aerosols, radiation, and meteorology. Two deployments have occurred from NASA/Dryden Flight Research Center, with flights to the eastern and central tropical Pacific. Two more deployments, targeting the western equatorial Pacific, are planned for 2014 from Guam and one other location. Over 100 vertical profiles from about 14 to 18 km have now been obtained from the tropics to midlatitudes, as well as long sections at nearly constant altitude. Results are shown here from the UAS Chromatograph for Atmospheric Trace Species (UCATS) instrument and other sensors. UCATS was configured to measure the long-lived tracers N2O, SF6, H2, and CH4, as well as water vapor, CO, and ozone. Results thus far have shown a mix of midlatitude and tropical air in the tropical and subtropical lower stratosphere, particularly for flights in November 2011. Recent results from February 2013 indicate much more homogeneous air masses in the TTL during this period. This homogeneity may be related to fact that these flights occurred in the middle of (northern) winter rather than fall, or to the 'sudden stratospheric warming' in January 2013, with sinking motion in the Arctic polar region and a corresponding rising motion and cooling in the tropics. Data will be presented in the context of trajectory model calculations of the origin and fate of the air

  13. Direct calculation of acoustic streaming including the boundary layer phenomena in an ultrasonic air pump

    NASA Astrophysics Data System (ADS)

    Wada, Yuji; Koyama, Daisuke; Nakamura, Kentaro

    2012-05-01

    Direct finite difference fluid simulation of acoustic streaming on the fine-meshed three-dimensiona model by graphics processing unit (GPU)-oriented calculation array is discussed. Airflows due to the acoustic traveling wave are induced when an intense sound field is generated in a gap between a bending transducer and a reflector. Calculation results showed good agreement with the measurements in the pressure distribution. In addition to that, several flow-vortices were observed near the boundary of the reflector and the transducer, which have been often discussed in acoustic tube near the boundary, and have never been observed in the calculation in the ultrasonic air pump of this type.

  14. Mixing layer height and the implications for air pollution over Beijing, China

    NASA Astrophysics Data System (ADS)

    Tang, G.; Zhang, J.; Münkel, C.; Song, T.; Hu, B.; Schäfer, K.; Liu, Z.; Xin, J.; Suppan, P.; Wang, Y.

    2015-10-01

    The mixing layer is an important meteorological factor that affects atmospheric pollution. A study of atmospheric pollution in the Beijing area was performed from July 2009 to December 2012, using a ceilometer, to observe and study the atmospheric mixing layer height (MLH). Based on a comparison and validation of multiple types of data, we evaluated the quality of the MLH data as observed by the ceilometer and found that the ceilometer underestimates MLH during neutral stratification caused by strong winds, whereas it overestimates MLH during dust crossing. By combining conventional meteorological data and PM2.5 and PM10 observational data, we screened the observational results for the MLH, and the ceilometer observations were fairly consistent with the meteorological radiosonde profile results. The correlation coefficient is more than 0.9, and the effective rate of acquired data is near 80 %. Further analysis of the variation in the MLH indicates that the MLH in the Beijing area exhibits the feature of being low in autumn and winter and being high in spring and summer. There is a significant correlation between the variation in the MLH and the sensible heat flux, whereas the diurnal variation in the mixing layer during summer is affected by the circulation of mountainous plain winds. By applying visibility as the index for the classification of atmospheric pollution degree, it is found that in comparison with a clear day, the variation of sensible heat and buoyancy term in turbulent kinetic energy (TKE) of a slight haze day is insignificant, but the reduction of shear term in TKE is near 70 % when visibility decreased from 10 to 5 km; in comparison with the slight haze day, the variation of shear term in TKE of medium and heavy haze days is insignificant, but the declination of sensible heat and buoyancy term in TKE are about 60 % when visibility decreased from 5 to 1 km. Although the correlation between the daily variation of MLH and visibility is very poor, the

  15. A Study of the Turbulent Layer in the Water at an Air-Water Interface.

    DTIC Science & Technology

    1985-01-01

    Shonting (1964, 1967, 1968, 1970), Simpson - .(1969), Yefimov and Khristoforov (1969, 1971), Tatra (1971), Thornton and Krapohl (1974), and Cavaleri et al...34Wind-induced drift currents," J. Fluid Mech., 68, 49-70, 1975. Yefimo,, V.V. and G.N. Khristoforov , "Some features of the velocity field in the layer...of wind-driven swell," Bull. (Izv.) A-cad. Sci. USSR, Atmospheric and Oceanic Physics, 5_, 597-602, 1969. Yefimov, V.V. and G.N. Khristoforov

  16. Observations From the Coupled Boundary Layer Air-Sea Transfer Experiment in Hurricanes

    NASA Astrophysics Data System (ADS)

    Black, P. G.

    2006-12-01

    The CBLAST field program conducted from 2002-2004 has shown that the wind speed range for which turbulent momentum and moisture exchange coefficients have been derived based upon direct flux measurements has been extended by 30 and 60 percent, respectively, from airborne observations in Hurricanes Fabian and Isabel in 2003. The drag coefficient (CD) values derived from CBLAST momentum flux measurements show CD becoming invariant with wind speed near a 23 ms-1 threshold rather than a hurricane-force threshold near 33 ms-1. Values above 23 ms-1 are lower than previous open ocean measurements. The Dalton number estimates (CE) derived from CBLAST moisture flux measurements are shown to be invariant with wind speed to 30 ms-1, in approximate agreement with previous measurements at lower winds. These observations imply a CE/CD ratio of approximately 0.7, suggesting that additional energy sources are necessary for hurricanes to achieve their maximum potential intensity. Two such additional mechanisms for augmented moisture flux in the boundary layer might be 1) augmented wave breaking by short-crested, fetch limited waves suggested by whitecap aerial coverage measurements, and 2) sea spray at high winds suggested by laboratory spray source function measurements. Linear coherent features in the hurricane boundary layer are a third mechanism, observed during CBLAST 2002 aircraft measurements, to have wavelengths of 0.9 to 1.2 km. Linear features of the same wavelength range were observed in nearly-concurrent RADARSAT Synthetic Aperture Radar (SAR) imagery. Arrays of drifting buoys and subsurface floats were successfully deployed ahead of Hurricanes Fabian (2003) and Frances (2004): 16 (6) and 38 (14) drifters (floats). Two types of surface drifters and three types of floats provided observations of surface and subsurface oceanic currents, temperature, salinity, gas exchange, bubble concentrations and surface wave spectra to a depth of 200 m on a continuous basis before

  17. The relationship between ozone formation and air temperature in the atmospheric surface layer

    NASA Astrophysics Data System (ADS)

    Belan, Boris D.; Savkin, Denis; Tolmachev, Gennadii

    2016-04-01

    Studying the formation and dynamics of ozone in the atmosphere is important due to several reasons. First, the contribution of tropospheric ozone to the global greenhouse effect is only slightly less than that of water vapor, carbon dioxide, and methane. Second, tropospheric ozone acts as a strong poison that has negative effects on human health, animals, and vegetation. Third, being a potent oxidizer, ozone destroys almost all materials, including platinum group metals and compounds. Fourthly, ozone is formed in situ from precursors as a result of photochemical processes, but not emitted into the atmosphere by any industrial enterprises directly. In this work, we present some results of the study aimed at the revealing relationship between ozone formation rate and surface air temperature in the background atmosphere. It has been found that this relationship is nonlinear. Analysis of the possible reasons showed that the nonlinear character of this relationship may be due to a nonlinear increase in the reaction constants versus air temperature and a quadratic increase in the concentration of hydrocarbons with increasing temperature. This work was supported by the Ministry of Education and Science contract no.14.613.21.0013 (ID: RFMEFI61314X0013).

  18. Restriction of a bacteriophage of Streptomyces albus G involving endonuclease SalI.

    PubMed Central

    Chater, K F; Wilde, L C

    1976-01-01

    The bacteriophage Pa16, isolated from soil on Streptomyces albus G, was restricted when transferred from an alternative host back to S. albus G. Extracted unmodified Pa16 deoxyribonucleic acid was cleaved at a single site by a cell-free extract of S. albus G. Fractions cleaving Pal6 deoxyribonucleic acid contained the endonuclease SalI first described by J. Arrand, P. Myers, and R. J. Roberts (unpublished data). A mutant of S. albus G was isolated which was defective in both restriction and modification of Pal6. This mutant lacked SalI activity. It is concluded that SalI is the agent of restriction of Pal6 by S. albus G. Images PMID:977549

  19. Non-Boltzmann Modeling for Air Shock-Layer Radiation at Lunar-Return Conditions

    NASA Technical Reports Server (NTRS)

    Johnston, Christopher O.; Hollis, Brian R.; Sutton, Kenneth

    2008-01-01

    This paper investigates the non-Boltzmann modeling of the radiating atomic and molecular electronic states present in lunar-return shock-layers. The Master Equation is derived for a general atom or molecule while accounting for a variety of excitation and de-excitation mechanisms. A new set of electronic-impact excitation rates is compiled for N, O, and N2+, which are the main radiating species for most lunar-return shock-layers. Based on these new rates, a novel approach of curve-fitting the non-Boltzmann populations of the radiating atomic and molecular states is developed. This new approach provides a simple and accurate method for calculating the atomic and molecular non-Boltzmann populations while avoiding the matrix inversion procedure required for the detailed solution of the Master Equation. The radiative flux values predicted by the present detailed non-Boltzmann model and the approximate curve-fitting approach are shown to agree within 5% for the Fire 1634 s case.

  20. Reduced kinetic mechanism of ignition for nonpremixed hydrogen/air in a supersonic mixing layer

    SciTech Connect

    Ju, Y.; Niioka, T. . Inst. of Fluid Science)

    1994-11-01

    Transient ignition processes in a two-dimensional spatially evolving supersonic mixing layer consisting of a parallel nonpremixed airstream and a hydrogen stream both with temperatures higher than 1,000 K were investigated numerically by using the full chemistry and its reduced chemistry. A phenomenon different from that examined in previous studies, in which ignition of hydrogen/oxygen mixtures was considered, was found in the nonpremixed case examined here. It was shown that the concentration of O was greater than that of OH before ignition, but became smaller with the development of ignition process. Fourteen important reactions for ignition were obtained and verified using sensitivity analyses of ignition delay time and radical concentrations. Several different four-step and three-step reduced kinetic mechanisms were then deduced by introducing the steady-state approximation to different species. Comparison of these reduced kinetic mechanisms with the full chemistry showed that the steady-state approximation of O used in previous studies caused serious errors in the prediction of ignition delay time in supersonic flow, in which nonpremixed character is predominant and the transport phenomenon is important. Ignition locations predicted with the proper four-step and three-step reduced kinetic mechanisms were within 5% and 20% of those predicted with the full chemistry. Finally, these two reduced mechanisms were used to evaluate the effect of viscous dissipation on ignition in the supersonic shear layer. Good agreements between the results of the present reduced kinetic mechanisms and those of the full chemistry were obtained.

  1. Effects of hypothalamic dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) secretion in male goats.

    PubMed

    Jin, Jin; Hara, Sayaka; Sawai, Ken; Fülöp, Ferenc; Nagy, György Miklos; Hashizume, Tsutomu

    2014-04-01

    The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) release in goats. The PRL-releasing response to an intravenous (i.v.) injection of SAL was examined after treatment with augmentation of central DA using carbidopa (carbi) and L-dopa in male goats under 8-h (8 h light, 16 h dark) or 16-h (16 h light, 8 h dark) photoperiod conditions. The carbi and L-dopa treatments reduced basal PRL concentrations in the 16-h photoperiod group (P < 0.05), while a reduction was not observed in the 8-h photoperiod group. The mean basal plasma PRL concentration in the control group for the 8-h photoperiod was lower than that for the 16-h photoperiod (P < 0.05). SAL significantly stimulated the release of PRL promptly after the injection in both the 8- and 16-h photoperiod groups (P < 0.05). PRL-releasing responses for the 16-h photoperiod were greater than those for the 8-h photoperiod (P < 0.05). The carbi and L-dopa treatments blunted SAL-induced PRL release in both the 8- and 16-h photoperiods (P < 0.05). These results indicate that hypothalamic DA blunts the SAL-induced release of PRL in male goats, regardless of the photoperiod, which suggests that both SAL and DA are involved in regulating the secretion of PRL in goats.

  2. Identification of methionine synthase (Sal k 3), as a novel allergen of Salsola kali pollen.

    PubMed

    Assarehzadegan, Mohammad Ali; Sankian, Mojtaba; Jabbari, Farahzad; Tehrani, Mohsen; Falak, Reza; Varasteh, Abdolreza

    2011-01-01

    Salsola kali pollen is a common cause of pollinosis during summer and early fall in desert and semi-desert regions. The aim of this study was the identification and characterization of Sal k 3, a new allergen from S. kali pollen. S. kali pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting using twelve S. kali allergic patients. Protein identification was carried out by the means of mass spectrometry. Using degenerated primers, two DNA fragments encoding N- and C-terminal domain of Sal k 3 were amplified by PCR, then cloned into the PTZ57R/T vector and sequenced. The open reading frame of Sal k 3 fragments were subcloned in the pET-32b(+) vector, expressed in E. coli, and purified by Ni2+ affinity chromatography. The IgE-binding capacity of rSal k 3 fragments was then studied by IgE-immunoblotting, inhibition assays, and skin prick tests. A 45-kDa allergen was identified as a fragment of the cobalamin-independent methionine synthase (MetE) by mass spectrometry and was detected in the sera of 8/12 (66.6%) of S. kali allergic patients. Moreover, inhibition assays demonstrated that the purified rSal k 3 fragments were similar to their counterparts in the crude extract. Sal k 3 represents a new allergen of S. kali pollen and seems to be an important allergenic compound in S. kali pollen.

  3. STEP - A temperature profiler for measuring the oceanic thermal boundary layer at the ocean-air interface

    SciTech Connect

    Mammen, T.C.; Von bosse, N. Salzgitter Elektronik GmbH, Flintbek, )

    1990-04-01

    A fast measuring system has been designed and built to determine the oceanic thermal microstructure at the ocean-air interface. The system consists of a profiler sonde, which ascends through the uppermost few meters of the ocean with a speed of typically 1 m/s and carries a fast temperature sensor with a time constant of 0.5 ms and a surface detector. The data rate is 8000 measurements per second and the achieved resolution in temperature is 0.01 K. The instrument has been designed for rough off-shore treatment and to avoid any disturbance of the boundary layer during measurements. Some measurements of the cool skin are shown from in situ experiments. 26 refs.

  4. Effect of atmospheric mixing layer depth variations on urban air quality and daily mortality during Saharan dust outbreaks.

    PubMed

    Pandolfi, M; Tobias, A; Alastuey, A; Sunyer, J; Schwartz, J; Lorente, J; Pey, J; Querol, X

    2014-10-01

    Several epidemiological studies have shown that the outbreaks of Saharan dust over southern European countries can cause negative health effects. The reasons for the increased toxicity of airborne particles during dust storms remain to be understood although the presence of biogenic factors carried by dust particles and the interaction between dust and man-made air pollution have been hypothesized as possible causes. Intriguingly, recent findings have also demonstrated that during Saharan dust outbreaks the local man-made particulates can have stronger effects on health than during days without outbreaks. We show that the thinning of the mixing layer (ML) during Saharan dust outbreaks, systematically described here for the first time, can trigger the observed higher toxicity of ambient local air. The mixing layer height (MLH) progressively reduced with increasing intensity of dust outbreaks thus causing a progressive accumulation of anthropogenic pollutants and favouring the formation of new fine particles or specific relevant species likely from condensation of accumulated gaseous precursors on dust particles surface. Overall, statistically significant associations of MLH with all-cause daily mortality were observed. Moreover, as the MLH reduced, the risk of mortality associated with the same concentration of particulate matter increased due to the observed pollutant accumulation. The association of MLH with daily mortality and the effect of ML thinning on particle toxicity exacerbated when Saharan dust outbreaks occurred suggesting a synergic effect of atmospheric pollutants on health which was amplified during dust outbreaks. Moreover, the results may reflect higher toxicity of primary particles which predominate on low MLH days.

  5. Effect of atmospheric mixing layer depth variations on urban air quality and daily mortality during Saharan dust outbreaks

    PubMed Central

    Pandolfi, M.; Tobias, A.; Alastuey, A.; Sunyer, J.; Schwartz, J.; Lorente, J.; Pey, J.; Querol, X.

    2016-01-01

    Several epidemiological studies have shown that the outbreaks of Saharan dust over southern European countries can cause negative health effects. The reasons for the increased toxicity of airborne particles during dust storms remain to be understood although the presence of biogenic factors carried by dust particles or the interaction between dust and man-made air pollution have been hypothesized as possible causes. Intriguingly, recent findings have also demonstrated that during Saharan dust outbreaks the local man-made particulates can have stronger effects on health than during days without outbreaks. We show that the thinning of the mixing layer (ML) during Saharan dust outbreaks, systematically described here for the first time, can trigger the observed higher toxicity of ambient local air. The mixing layer height (MLH) progressively reduced with increasing intensity of dust outbreaks thus causing a progressive accumulation of anthropogenic pollutants and favouring the formation of new fine particles or specific relevant species likely from condensation of accumulated gaseous precursors on dust particles surface. Overall, statistically significant associations of MLH with all-cause daily mortality were observed. Moreover, as the MLH reduced, the risk of mortality associated with the same concentration of particulate matter increased due to the observed pollutants accumulation. The association of MLH with daily mortality and the effect of ML thinning on particle toxicity exacerbated when Saharan dust outbreaks occurred suggesting a synergic effect of atmospheric pollutants on health which was amplified during dust outbreaks. Moreover, the results may reflect higher toxicity of primary particles which predominate on low MLH days. PMID:25051327

  6. Influence of cathode opening size and wetting properties of diffusion layers on the performance of air-breathing PEMFCs

    NASA Astrophysics Data System (ADS)

    Schmitz, A.; Tranitz, M.; Eccarius, S.; Weil, A.; Hebling, C.

    Air-breathing PEMFCs consist of an open cathodic side to allow an entirely passive supply of oxygen by diffusion. Furthermore, a large fraction of the produced water is removed by evaporation from the open cathode. Gas diffusion layers (GDLs) and the opening size of the cathode have a crucial influence on the performance of an air-breathing PEMFC. In order to assure an unobstructed supply of oxygen the water has to be removed efficiently and condensation in the GDL has to be avoided. On the other hand good humidification of the membrane has to be achieved to obtain high protonic conductivity. In this paper the influence of varying cathodic opening sizes (33%, 50% and 80% opening ratios) and of GDLs with different wetting properties are analysed. GDLs with hydrophobic and hydrophilic properties are prepared by coating of untreated GDLs (Toray ® carbon paper TGP-H-120, thickness of 350 μm). The air-breathing PEMFC test samples are realised using printed circuit board (PCB) technology. The cell samples were characterised over the entire potential range (0-0.95 V) by extensive measurements of the current density, the temperature and the cell impedance at 1 kHz. Additionally, measurements of the water balance were carried out at distinct operation points. The best cell performance was achieved with the largest opening ratio (80%) and an untreated GDL. At the maximum power point, this cell sample achieved a power density of 100 mW cm -2 at a moderate cell temperature of 43 °C. Furthermore, it could be shown that GDLs with hydrophilic or intense hydrophobic properties do not improve the performance of an air-breathing PEMFC. Based on the extensive characterisations, two design rules for air-breathing PEMFCs could be formulated. Firstly, it is crucial to maximise the cathode opening as far as an appropriate compression pressure of the cell assembly and therewith low contact resistance can be assured. Secondly, it is advantageous to use an untreated, slightly hydrophobic

  7. Hypersonic ionizing air viscous shock-layer flows over nonanalytic blunt bodies

    NASA Technical Reports Server (NTRS)

    Miner, E. W.; Lewis, C. H.

    1975-01-01

    The equations which govern the viscous shock-layer flow are presented and the method by which the equations are solved is discussed. The predictions of the present finite-difference method are compared with other numerical predictions as well as with experimental data. The principal emphasis is placed on predictions of the viscous flowfield for the windward plane of symmetry of the space shuttle orbiter and other axisymmetric bodies which approximate the shuttle orbiter geometry. Experimental data on two slender sphere-cones at hypersonic conditions are also considered. The present predictions agreed well with experimental data and with the past predictions. Substantial differences were found between present predictions and more approximate methods.

  8. The defective seed5 (des5) mutant: effects on barley seed development and HvDek1, HvCr4, and HvSal1 gene regulation.

    PubMed

    Olsen, Lene T; Divon, Hege H; Al, Ronald; Fosnes, Kjetil; Lid, Stein Erik; Opsahl-Sorteberg, Hilde-Gunn

    2008-01-01

    Barley, one of the major small grain crops, is especially important in climatically demanding agricultural areas of the world, with multiple uses within food, feed, and beverage. The barley endosperm is further of special scientific interest due to its three aleurone cell layers, with the potential of bringing forward the molecular understanding of seed development and cell specification from Arabidopsis and maize. Work done in Arabidopsis and maize indicate the presence of conserved seed developmental pathways where Crinkly4 (Cr4), Defective kernel1 (Dek1), and Supernumerary aleurone layer1 (Sal1) are key players. With the use of microscopy, a comprehensive phenotypic characterization of the barley defective seed5 (des5) mutant is presented here. The analysis further extends to molecular quantification of gene expression changes in the des5 mutant by qRT-PCR. Moreover, full-length genomic sequences of the barley orthologues were generated and these were annotated as HvDek1, HvCr4, and HvSal1. The most striking results in this study are the patchy reduction in number of aleurone cells, rudimentary anticlinal aleurone cell walls, and the specific change of HvCr4 expression compared to HvDek1 and HvSal1. The data presented support the involvement of Hvdes5 in establishing aleurone cells. Finally, how these results might affect the current model of aleurone and epidermal cell identity and development is discussed with a speculation regarding a possible role of Des5 in regulating cell division/ secondary cell wall building.

  9. Hygroscopic Growth of Self-Assembled Layered Surfactant Molecules at the Interface between Air and Organic Salts

    SciTech Connect

    Shin, Yongsoon; Wang, Li Q.; Fryxell, Glen E.; Exarhos, Gregory J.

    2005-04-01

    We report here a self-assembly of surfactant molecules at the interface of air/hygroscopic quaternary ammonium salts, tetrabutylammonium acetate (TBAAc). Homogeneously dissolved surfactant molecules at 100 C self-assemble upon contacting air due to high moisture adsorption behavior of the organic salt when cooling down. Highly ordered lamellar phases with different lattice spacings have been observed when surfactants with various lengths of alkyl chains were used. CnTMAB/TBAAc systems showed all trans conformation of interior methylene carbons and interdigited bilayers with an average CH2 increment of 0.119nm, while CnNH2/TBAAc systems showed trans/gauche mixed conformations of interior methylene carbons and bilayers with an average CH2 increment of 0.247nm. CnNH2s in CnNH2/TBAAc formed bilayers through water-mediated intermolecular hydrogen bonds with a water layer thickness of 0.51-0.61nm. In CnTAB/TBAAc, as the head group of CnTAB is bigger, the interdigited bilayer thickness (d-spacing) is smaller because their bigger head groups accommodate enough space for alkyl tails to come in between them.

  10. Foaming and adsorption behavior of bovine and camel proteins mixed layers at the air/water interface.

    PubMed

    Lajnaf, Roua; Picart-Palmade, Laetitia; Attia, Hamadi; Marchesseau, Sylvie; Ayadi, M A

    2017-03-01

    The aim of this work was to examine foaming and interfacial behavior of three milk protein mixtures, bovine α-lactalbumin-β-casein (M1), camel α-lactalbumin-β-casein (M2) and β-lactoglobulin-β-casein (M3), alone and in binary mixtures, at the air/water interface in order to better understand the foaming properties of bovine and camel milks. Different mixture ratios (100:0; 75:25; 50:50; 25:75; 0:100) were used during foaming tests and interfacial protein interactions were studied with a pendant drop tensiometer. Experimental results evidenced that the greatest foam was obtained with a higher β-casein amount in all camel and bovine mixtures. Good correlation was observed with the adsorption and the interfacial rheological properties of camel and bovine protein mixtures. The proteins adsorbed layers are mainly affected by the presence of β-casein molecules, which are probably the most abundant protein at interface and the most efficient in reducing the interfacial properties. In contrast of, the globular proteins, α-lactalbumin and β-lactoglobulin that are involved in the protein layer composition, but could not compact well at the interface to ensure foams creation and stabilization because of their rigid molecular structure.

  11. Magnetic Nanodrug Delivery Through the Mucus Layer of Air-Liquid Interface Cultured Primary Normal Human Tracheobronchial Epithelial Cells.

    PubMed

    Economou, E C; Marinelli, S; Smith, M C; Routt, A A; Kravets, V V; Chu, H W; Spendier, K; Celinski, Z J

    2016-09-01

    Superparamagnetic iron oxide (Fe3O4) and highly anisotropic barium hexaferrite (BaFe12O19) nanoparticles were coated with an anti-inflammatory drug and magnetically transported through mucus produced by primary human airway epithelial cells. Using wet planetary ball milling, dl-2-amino-3-phosphonopropionic acid-coated BaFe12O19 nano-particles (BaNPs) of 1-100 nm in diameter were prepared in water. BaNPs and conventional 20-30-nm Fe3O4 nanoparticles (FeNPs) were then encased in a polymer (PLGA) loaded with dexamethasone (Dex) and tagged for imaging. PLGA-Dex-coated BaNPs and FeNPs were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) magnetometry. Both PLGA-Dex-coated BaNPs and FeNPs were transferred to the surface of a ~100-μm thick mucus layer of air-liquid interface cultured primary normal human tracheobronchial epithelial (NHTE) cells. Within 30 min, the nanoparticles were pulled successfully through the mucus layer by a permanent neodymium magnet. The penetration time of the nanomedicine was monitored using confocal microscopy and tailored by varying the thickness of the PLGA-Dex coating around the particles.

  12. Magnetic Nanodrug Delivery Through the Mucus Layer of Air-Liquid Interface Cultured Primary Normal Human Tracheobronchial Epithelial Cells

    PubMed Central

    Economou, E. C.; Marinelli, S.; Smith, M. C.; Routt, A. A.; Kravets, V. V.; Chu, H. W.; Spendier, K.; Celinski, Z. J.

    2016-01-01

    Superparamagnetic iron oxide (Fe3O4) and highly anisotropic barium hexaferrite (BaFe12O19) nanoparticles were coated with an anti-inflammatory drug and magnetically transported through mucus produced by primary human airway epithelial cells. Using wet planetary ball milling, dl-2-amino-3-phosphonopropionic acid-coated BaFe12O19 nano-particles (BaNPs) of 1–100 nm in diameter were prepared in water. BaNPs and conventional 20–30-nm Fe3O4 nanoparticles (FeNPs) were then encased in a polymer (PLGA) loaded with dexamethasone (Dex) and tagged for imaging. PLGA-Dex-coated BaNPs and FeNPs were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) magnetometry. Both PLGA-Dex-coated BaNPs and FeNPs were transferred to the surface of a ~100-μm thick mucus layer of air-liquid interface cultured primary normal human tracheobronchial epithelial (NHTE) cells. Within 30 min, the nanoparticles were pulled successfully through the mucus layer by a permanent neodymium magnet. The penetration time of the nanomedicine was monitored using confocal microscopy and tailored by varying the thickness of the PLGA-Dex coating around the particles. PMID:27774374

  13. Investigation of inhomogeneity and anisotropy in near ground layers of atmospheric air turbulence using image motion monitoring method

    NASA Astrophysics Data System (ADS)

    Mohammadi Razi, Ebrahim; Rasouli, Saifollah

    2017-01-01

    In this work the anisotropy and inhomogeneity of real atmospheric turbulence have been investigated using image motion monitoring and differential image motion monitoring methods. For this purpose the light beam of a point source is propagated through the atmospheric turbulence layers in horizontal path and then impinged to a telescope aperture. The telescope and point source were 350 m apart. In front of the telescope's aperture a mask consisting of four subapertures was installed. Image of the point source was formed on a sensitive CCD camera located at the focal plane of the telescope. By displacing CCD camera along the axis of telescope, four distinct images were recorded. Angle of arrival (AA) of each spot was calculated by image processing. Air turbulence causes AA to fluctuate. By comparing AA fluctuation variances of different spots in two directions isotropy and homogeneity of turbulence were studied. Results have shown that atmospheric turbulence in near ground layers is treated as an anisotropic and inhomogeneous medium. In addition, the inhomogeneity and anisotropy of turbulence decreases with the distance from earth surface.

  14. Air-stable efficient inverted polymer solar cells using solution-processed nanocrystalline ZnO interfacial layer.

    PubMed

    Tan, Mein Jin; Zhong, Shu; Li, Jun; Chen, Zhikuan; Chen, Wei

    2013-06-12

    In this work, efficient bulk heterojunction (BHJ) organic solar cells (OSC) in inverted configuration have been demonstrated. Power conversion efficiency (PCE) of 3.7% is reported for OSC employing silver top electrodes, molybdenum trioxide (MoO3) as the hole-transport interlayer (HTL), active layer comprising of poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as well as a nanocrystalline solution-synthesized zinc oxide (ZnO) nanoparticle (NP) film as the electron-transport layer (ETL). By using solution-processable ZnO crystalline NPs as ETL, we can eliminate the typical high temperature processing/annealing step, which is widely adopted in the conventional ZnO ETL fabrication process via the sol-gel method. Such highly crystalline ZnO NP films can enhance charge collection at the electrodes. It is also found that inverted OSCs exhibit greater air stability and lifetime performance compared to the OSC employing the normal structure.

  15. Finite-Difference Solution for Laminar or Turbulent Boundary Layer Flow over Axisymmetric Bodies with Ideal Gas, CF4, or Equilibrium Air Chemistry

    NASA Technical Reports Server (NTRS)

    Hamilton, H. Harris, II; Millman, Daniel R.; Greendyke, Robert B.

    1992-01-01

    A computer code was developed that uses an implicit finite-difference technique to solve nonsimilar, axisymmetric boundary layer equations for both laminar and turbulent flow. The code can treat ideal gases, air in chemical equilibrium, and carbon tetrafluoride (CF4), which is a useful gas for hypersonic blunt-body simulations. This is the only known boundary layer code that can treat CF4. Comparisons with experimental data have demonstrated that accurate solutions are obtained. The method should prove useful as an analysis tool for comparing calculations with wind tunnel experiments and for making calculations about flight vehicles where equilibrium air chemistry assumptions are valid.

  16. Effect of eggshell temperature and a hole in the air cell on the perinatal development and physiology of layer hatchlings.

    PubMed

    Molenaar, R; de Vries, S; van den Anker, I; Meijerhof, R; Kemp, B; van den Brand, H

    2010-08-01

    To investigate the effect of incubation conditions on layer hatchlings, an experiment was performed in which layer eggs were incubated at a normal (37.8 degrees C) or high (38.9 degrees C) eggshell temperature (EST) and a hole was punctured in the air cell of half of the eggs in both EST treatments from d 14 of incubation onward. Chick development, plasma metabolites, and hepatic glycogen were measured at 12 h after emergence from the eggshell. Embryo mortality was not affected by the EST or hole treatment. At the high EST, yolk-free body mass was 0.7 g lower and residual yolk weight was 0.7 g higher than at the normal EST. This may be related to the shorter incubation duration at the high EST. Relative heart, lung, stomach, liver, spleen, and intestinal weights were lower in the high EST than in the normal EST group. Yolk-free body mass did not differ between eggs with or without a hole, but residual yolk weight was slightly lower in eggs with a hole (0.3 g). Relative lung weights were higher in eggs with than without a hole, whereas no effect on other organs was found. Plasma glucose, lactate, and uric acid concentrations did not differ between the EST or hole treatments. Hepatic glycogen was lower in the high EST (7.3 mg) than in the normal EST group (11.2 mg) at 12 h after emergence from the eggshell, and this effect may be related to the shorter hatching process at the high EST. Hepatic glycogen levels were lower in eggs with a hole (8.6 mg) compared with eggs without a hole (10.0 mg), and this may be related to the longer period between external pipping and hatching in eggs with a hole. In conclusion, the EST and hole treatment did not interact, and neither treatments affected embryonic survival. High EST negatively affected hatchling development and seemed to change the carbohydrate metabolism in layer embryos. The effect of a hole in the air cell was limited.

  17. Laboratory investigations of the heat and momentum transfer in the stably stratified air turbulent boundary layer above the wavy surface

    NASA Astrophysics Data System (ADS)

    Sergeev, Daniil; Troitskaya, Yuliya; Vdovin, Maxim

    2015-04-01

    Investigation of small scale transfer processes between the ocean and atmosphere in the boundary and its parameterization on the meteorological conditions (wind and surface waves parameters) is very important for weather forecasts modeling [1]. The accuracy of the predictions taking in to account the so named bulk-formulas strongly depends on the quality empirical data. That is why the laboratory modeling sometimes is preferable (see [2]) then in situ measurements for obtaining enough ensembles of the data with a good accuracy in control conditions, first of all in a case of severe conditions (strong winds with intensive wave breaking and sprays generation). In this investigation laboratory modeling was performed on the Thermostratified Wind-Wave Channel of the IAP RAS (see. [3]). Experiments were carried out for the wind speeds up to 18.5 m/s (corresponding the equivalent 10-m wind speed 30 m/s). For the possibility of varying parameters of surface roughness independently on the wind flow a special system basing on the submerged mosquito mesh (cell of 2*2 mm) was used (see [4]). The roughness was controlled by the depth of the mesh installation under the free surface (no waves when the mesh was on the surface and maximum wave amplitude for the maximum depth). So, for each wind speed several cases of the waves parameters were investigated. During experiments a stable stratification of the boundary layer of air flow was obtained. Temperature of the heating air was 33-37 degrees (depending on the reference wind speed), and the water temperature was 14-16 degrees. The Pitote gauge and hotwire were used together for measuring velocity and temperature profiles. Also indirect estimations of the total volume of the phase of sprays were obtained by analyzing hotwire signals errors during droplets hits. Then aerodynamic drag CD and heat transfer Ch coefficients were obtained by profiling method. It was shown that that these parameters are very sensitive to the intensity of

  18. Biogenic ice nuclei in boundary layer air over two U.S. High Plains agricultural regions

    NASA Astrophysics Data System (ADS)

    Garcia, Elvin; Hill, Thomas C. J.; Prenni, Anthony J.; Demott, Paul J.; Franc, Gary D.; Kreidenweis, Sonia M.

    2012-09-01

    With 18% of the total U.S. landmass devoted to croplands, farmland and farming activities are potentially major sources of biogenic particles to the atmosphere. Farms harbor large populations of microbes both in the soil and on plant surfaces which, if injected into the atmosphere, may serve as nuclei for clouds. In this study, we investigated two farms as potential sources of biological ice nuclei (IN): an organic farm in Colorado and a cornfield in Nebraska. We used a continuous-flow diffusion chamber (CFDC) to obtain real-time measurements of IN at these farm sites. Total aerosol particles were also collected at the sites, and their temperature-dependent ice nucleating activity was determined using the drop freezing method. Quantitative polymerase chain reaction and DNA sequencing of 16S rDNA clone libraries were used to test aerosols and washings of local vegetation for abundance of theinagene in ice nucleation active bacteria (from the well-known group within theγ-Proteobacteria) and to identify airborne primary biological aerosol particles. The vegetation in each of these farms contained 6 × 105 to 2 × 107 ina genes per gram vegetation. In contrast to the vegetation, airborne ina gene concentrations at the organic farm were typically below detectable limits, demonstrating a disconnect between local vegetative sources and the air above them. However, for measurements made during combine harvesting at the Nebraska corn field, ina gene concentrations were 19 L-1, with maximum IN concentrations of 50 L-1 determined from the CFDC at -20°C and above water saturation. At both farms, there was also an apparent biological contribution to the IN population which did not contain the ina gene.

  19. Saharan Air and Atlantic Tropical Cyclone Suppression From a Global Modeling Perspective

    NASA Technical Reports Server (NTRS)

    Reale, O.; Lau, W. K. M.; daSilva, A.; Kim, K.-M.

    2007-01-01

    During summer 2006, the NASA African Monsoon Multidisciplinary Analysis (NAMMA) organized a field campaign in Africa called Special Observation Period (SOP-3), in which scientists in the field were involved in a number of surface network and aircraft measurements. One of the scientific goals of the campaign was to understand the nature and causes for tropical cyclogenesis originating out of African Easterly Waves (AEWs, westward propagating atmospheric disturbances sometimes associated with precursors of hurricanes), and the role that the Saharan Air Layer (SAL, a hot and dry air layer advecting large amounts of dust) can play in the formation or suppression of tropical cyclones. During the NAMMA campaign a high-resolution global model, the NASA GEOS-5, was operationally run by the NASA Global Modeling and Assimilation Office (GMAO) in support to the mission. The daily GEOS-5 forecasts were found to be very useful by decision-making scientists in the field as an aid to discriminate between developing and non-developing AEWs and plan the flight tracks. In the post-event analyses which were performed mostly by the Goddard Laboratory for Atmospheres, two events were highlighted: a non-developing AEW which appeared to have been suppressed by Saharan air, compared to a developing AEW which was the precursor of hurricane Helene. Both events were successfully predicted by the GEOS-5 during the real-time forecasts provided in support to the mission. In this work it is found that very steep moisture gradients and a strong thermal dipole, with relatively warm air in the mid-troposphere and cool air below, are associated with SAL in both the GEOS-5 forecasts and the NCEP analyses, even at -great distance- from the Sahara. The presence of these unusual thermodynamic features over the Atlantic Ocean, at several thousands of kilometers from the African coastline, is suggestive that SAL mixing is very minimal and that the model's capability of retaining the different properties

  20. Impact of the Loess Plateau on the atmospheric boundary layer structure and air quality in the North China Plain: a case study.

    PubMed

    Hu, Xiao-Ming; Ma, ZhiQiang; Lin, Weili; Zhang, Hongliang; Hu, Jianlin; Wang, Ying; Xu, Xiaobin; Fuentes, Jose D; Xue, Ming

    2014-11-15

    The North China Plain (NCP), to the east of the Loess Plateau, experiences severe regional air pollution. During the daytime in the summer, the Loess Plateau acts as an elevated heat source. The impacts of such a thermal effect on meteorological phenomena (e.g., waves, precipitation) in this region have been discussed. However, its impacts on the atmospheric boundary layer structure and air quality have not been reported. It is hypothesized that the thermal effect of the Plateau likely modulates the boundary layer structure and ambient concentrations of pollutants over the NCP under certain meteorological conditions. Thus, this study investigates such effect and its impacts using measurements and three-dimensional model simulations. It is found that in the presence of daytime westerly wind in the lower troposphere (~1 km above the NCP), warmer air above the Loess Plateau was transported over the NCP and imposed a thermal inversion above the mixed boundary layer, which acted as a lid and suppressed the mixed layer growth. As a result, pollutants accumulated in the shallow mixed layer and ozone was efficiently produced. The downward branch of the thermally-induced Mountain-Plains Solenoid circulation over the NCP contributed to enhancing the capping inversion and exacerbating air pollution. Previous studies have reported that low mixed layer, a factor for elevated pollution in the NCP, may be caused by aerosol scattering and absorption of solar radiation, frontal inversion, and large scale subsidence. The present study revealed a different mechanism (i.e., westerly warm advection) for the suppression of the mixed layer in summer NCP, which caused severe O3 pollution. This study has important implications for understanding the essential meteorological factors for pollution episodes in this region and forecasting these severe events.

  1. Transfer-printing of active layers to achieve high quality interfaces in sequentially deposited multilayer inverted polymer solar cells fabricated in air

    PubMed Central

    Vohra, Varun; Anzai, Takuya; Inaba, Shusei; Porzio, William; Barba, Luisa

    2016-01-01

    Abstract Polymer solar cells (PSCs) are greatly influenced by both the vertical concentration gradient in the active layer and the quality of the various interfaces. To achieve vertical concentration gradients in inverted PSCs, a sequential deposition approach is necessary. However, a direct approach to sequential deposition by spin-coating results in partial dissolution of the underlying layers which decreases the control over the process and results in not well-defined interfaces. Here, we demonstrate that by using a transfer-printing process based on polydimethylsiloxane (PDMS) stamps we can obtain increased control over the thickness of the various layers while at the same time increasing the quality of the interfaces and the overall concentration gradient within the active layer of PSCs prepared in air. To optimize the process and understand the influence of various interlayers, our approach is based on surface free energy, spreading parameters and work of adhesion calculations. The key parameter presented here is the insertion of high quality hole transporting and electron transporting layers, respectively above and underneath the active layer of the inverted structure PSC which not only facilitates the transfer process but also induces the adequate vertical concentration gradient in the device to facilitate charge extraction. The resulting non-encapsulated devices (active layer prepared in air) demonstrate over 40% increase in power conversion efficiency with respect to the reference spin-coated inverted PSCs. PMID:27877901

  2. The relation between air pollution data and planetary boundary layer quantities in a complex coastal industrial site nearby populated areas.

    NASA Astrophysics Data System (ADS)

    Mammarella, M. C.; Grandoni, G.; Fernando, J.; Cacciani, M.; di Sabatino, S.; Favaron, M.; Fedele, P.

    2010-09-01

    The connection among boundary layer phenomena, atmospheric pollutant dynamics and human health is an established fact, taking many different forms depending on local characteristics, including slope and position of relief and/or coastline, surface roughness, emission patterns. The problem is especially interesting in complex and coastal terrain, where concurrence of slope and sea induced local circulation interact reciprocally, yielding a complex pattern whose interpretation may go beyond pure modeling, and devise specific measurements among which the planetary boundary layer (PBL) height. An occasion for studying this important theme has been offered by Regione Molise and Valle del Biferno Consortium (COSIB), for the specific case of the industrial complex of Valle del Biferno, 3 km inland of Termoli, in Central Italy, on the Adriatic coast. The local government, sensitive to air quality and public health in the industrial area, together with COSIB has co-financed a research project aimed at gaining knowledge about local meteorology, PBL phenomena and atmospheric pollutant dispersion in the area. Expected results include new air quality monitoring and control methodologies in Valle del Biferno for a sustainable development in an environmentally respectful manner, at a site already characterized by a high environmental and landscape value. The research project, developed by ENEA, has began in 2007 and will conclude in December 2010. Project activities involve research group from Europe, the United States of America, and the Russian Federation. Scientific and practical results will be published and presented in occasion of the final workshop to be held on project conclusion. The scientific interest of Valle del Biferno case stems from the specific local characteristics at site. Given the valley orientation respect to mean synoptic circulation, local effects as sea and slope breezes are dominant, and a complex wind regime develops affecting local transport and

  3. Semi-rechargeable Aluminum-Air Battery with a TiO2 Internal Layer with Plain Salt Water as an Electrolyte

    NASA Astrophysics Data System (ADS)

    Mori, Ryohei

    2016-07-01

    To develop a semi-rechargeable aluminum-air battery, we attempted to insert various kinds of ceramic oxides between an aqueous NaCl electrolyte and an aluminum anode. From cyclic voltammetry experiments, we found that some of the ceramic oxide materials underwent an oxidation-reduction reaction, which indicates the occurrence of a faradaic electrochemical reaction. Using a TiO2 film as an internal layer, we successfully prepared an aluminum-air battery with secondary battery behavior. However, cell impedance increased as the charge/discharge reactions proceeded probably because of accumulation of byproducts in the cell components and the air cathode. Results of quantum calculations and x-ray photoelectron spectroscopy suggest the possibility of developing an aluminum rechargeable battery using TiO2 as an internal layer.

  4. Atomic Layer Deposition of TiO2 for a High-Efficiency Hole-Blocking Layer in Hole-Conductor-Free Perovskite Solar Cells Processed in Ambient Air.

    PubMed

    Hu, Hang; Dong, Binghai; Hu, Huating; Chen, Fengxiang; Kong, Mengqin; Zhang, Qiuping; Luo, Tianyue; Zhao, Li; Guo, Zhiguang; Li, Jing; Xu, Zuxun; Wang, Shimin; Eder, Dominik; Wan, Li

    2016-07-20

    In this study we design and construct high-efficiency, low-cost, highly stable, hole-conductor-free, solid-state perovskite solar cells, with TiO2 as the electron transport layer (ETL) and carbon as the hole collection layer, in ambient air. First, uniform, pinhole-free TiO2 films of various thicknesses were deposited on fluorine-doped tin oxide (FTO) electrodes by atomic layer deposition (ALD) technology. Based on these TiO2 films, a series of hole-conductor-free perovskite solar cells (PSCs) with carbon as the counter electrode were fabricated in ambient air, and the effect of thickness of TiO2 compact film on the device performance was investigated in detail. It was found that the performance of PSCs depends on the thickness of the compact layer due to the difference in surface roughness, transmittance, charge transport resistance, electron-hole recombination rate, and the charge lifetime. The best-performance devices based on optimized TiO2 compact film (by 2000 cycles ALD) can achieve power conversion efficiencies (PCEs) of as high as 7.82%. Furthermore, they can maintain over 96% of their initial PCE after 651 h (about 1 month) storage in ambient air, thus exhibiting excellent long-term stability.

  5. Tensiometry and dilational rheology of mixed β-lactoglobulin/ionic surfactant adsorption layers at water/air and water/hexane interfaces.

    PubMed

    Dan, Abhijit; Gochev, Georgi; Miller, Reinhard

    2015-07-01

    Oscillating drop tensiometry was applied to study adsorbed interfacial layers at water/air and water/hexane interfaces formed from mixed solutions of β-lactoglobulin (BLG, 1 μM in 10 mM buffer, pH 7 - negative net charge) and the anionic surfactant SDS or the cationic DoTAB. The interfacial pressure Π and the dilational viscoelasticity modulus |E| of the mixed layers were measured for mixtures of varying surfactant concentrations. The double capillary technique was employed which enables exchange of the protein solution in the drop bulk by surfactant solution (sequential adsorption) or by pure buffer (washing out). The first protocol allows probing the influence of the surfactant on a pre-adsorbed protein layer thus studying the protein/surfactant interactions at the interface. The second protocol gives access to the residual values of Π and |E| measured after the washing out procedure thus bringing information about the process of protein desorption. The DoTAB/BLG complexes exhibit higher surface activity and higher resistance to desorption in comparison with those for the SDS/BLG complexes due to hydrophobization via electrostatic binding of surfactant molecules. The neutral DoTAB/BLG complexes achieve maximum elastic response of the mixed layer. Mixed BLG/surfactant layers at the water/oil interface are found to reach higher surface pressure and lower maximum dilational elasticity than those at the water/air surface. The sequential adsorption mode experiments and the desorption study reveal that binding of DoTAB to pre-adsorbed BLG globules is somehow restricted at the water/air surface in comparison with the case of complex formation in the solution bulk and subsequently adsorbed at the water/air surface. Maximum elasticity is achieved with washed out layers obtained after simultaneous adsorption, i.e. isolation of the most surface active DoTAB/BLG complex. These specific effects are much less pronounced at the W/H interface.

  6. Study of an unitised bidirectional vanadium/air redox flow battery comprising a two-layered cathode

    NASA Astrophysics Data System (ADS)

    grosse Austing, Jan; Nunes Kirchner, Carolina; Hammer, Eva-Maria; Komsiyska, Lidiya; Wittstock, Gunther

    2015-01-01

    The performance of a unitised bidirectional vanadium/air redox flow battery (VARFB) is described. It contains a two-layered cathode consisting of a gas diffusion electrode (GDE) with Pt/C catalyst for discharging and of an IrO2 modified graphite felt for charging. A simple routine is shown for the modification of a graphite felt with IrO2. A maximum energy efficiency of 41.7% at a current density of 20 mA cm-2 as well as an average discharge power density of 34.6 mW cm-2 at 40 mA cm-2 were obtained for VARFB operation at room temperature with the novel cathode setup. A dynamic hydrogen electrode was used to monitor half cell potentials during operation allowing to quantify the contribution of the cathode to the overall performance of the VARFB. Four consecutive cycles revealed that crossover of vanadium ions took place and irreversible degradation processes within the reaction unit lead to a performance decrease.

  7. Structural and electrochemical stability of Li-rich layer structured Li2MoO3 in air

    NASA Astrophysics Data System (ADS)

    Ma, Jun; Gao, Yurui; Wang, Zhaoxiang; Chen, Liquan

    2014-07-01

    Li2MnO3 is an important component of the Li-rich Mn-based high-capacity cathode material for lithium ion batteries, xLi2MnO3·(1 - x)LiM‧O2 composites. Replacing Li2MnO3 with iso-structured Li2MoO3 is expected to improve the rate performance and suppress the oxygen release of the composites at high potentials due to the higher electric conductivity of Li2MoO3 and its more facile charge compensation (by Mo4+/Mo6+ redox) upon Li removal than that of Li2MnO3. As part of our series work on the Li2MoO3-based Li-rich layer structured cathode materials, this article is to study the structural and performance stability of Li2MoO3 in air. The obtained information will shed light on the development and application of xLi2MoO3·(1 - x)LiM‧O2 composite cathode materials though Li2MoO3 will not be applied as an independent cathode material.

  8. Protection against tauopathy by the drug candidates NAP (davunetide) and D-SAL: biochemical, cellular and behavioral aspects.

    PubMed

    Shiryaev, Natalia; Pikman, Regina; Giladi, Eliezer; Gozes, Illana

    2011-01-01

    Activity-dependent neuroprotective protein (ADNP) is essential for brain formation and partial deficiency in ADNP results in cognitive deficits coupled with tauopathy and neuronal cell death. Our previous results indicated that a peptide snippet from ADNP, NAPVSIPQ (NAP, generic name, davunetide) can restore in part ADNP deficiencies. NAP interacts with tubulin and this interaction is displaced by the NAP related peptide that is derived from activity-dependent neurotrophic factor (ADNF), SALLRSIPA (SAL) and its all D-amino acid peptide derivative (D-SAL, also known as AL-309). Both NAP and D-SAL were shown to protect neurons against amyloid beta toxicity however the mechanism of protection is still under investigation. In addition, NAP protects against tau hyperphosphorylation associated with ADNP deficiency, in vivo. To investigate whether the mechanism of in vitro neuroprotection relates to the in vivo protection against tauopathy and to draw potential additional parallelism between NAP and D-SAL, we asked if: 1]NAP and D-SAL protect against amyloid beta related tau hyperphosphorylation in vitro; and 2] D-SAL protects against haploinsufficiency in ADNP, inhibiting tauopathy in vivo. Assessment of NAP and D-SAL neuroprotection in primary cortical neuro-glial cultures treated with amyloid beta showed that both peptides reduced toxin-related neuronal damage and protected against tau hyperphosphorylation. In vivo, chronic D-SAL administration protected against tau hyperphosphorylation associated with ADNP deficiency (ADNP+/- mice), showing for the first time protection against deficits in odor discrimination and in social recognition. These studies associate neuroprotection in vivo and in vitro and provide a broad base for future drug development based on NAP and D-SAL against multiple neurodegenerative conditions.

  9. NiMn layered double hydroxides as efficient electrocatalysts for the oxygen evolution reaction and their application in rechargeable Zn-air batteries.

    PubMed

    Sumboja, Afriyanti; Chen, Jingwei; Zong, Yun; Lee, Pooi See; Liu, Zhaolin

    2017-01-05

    High performance catalysts for the oxygen evolution reaction (OER) are in demand to improve the re-chargeability of Zn-air batteries. In this work, atomically dispersed NiMn layered double hydroxides are prepared via simple hydrothermal synthesis and tested as the OER catalyst in rechargeable Zn-air batteries. NiMn layered double hydroxides with the optimized Ni : Mn molar feeding ratio have good crystallinity, big interlayer spacing, and large surface area, which are beneficial to enhance their catalytic activity. They are highly active and stable during the OER, showing an overpotential of 0.35 V, a Tafel slope of 40 mV dec(-1), and remarkable stability during 16 h of a chronopotentiometry test. Rechargeable Zn-air batteries with NiMn layered double hydroxides as the OER catalyst exhibit a low charge voltage of ≈2 V which is stable for up to 200 cycles. This study illustrates a platform to enhance the catalytic activity of the OER catalyst via fine-tuning the composition and physical properties of the materials and their application for rechargeable metal-air batteries.

  10. Engendering Long-Term Air and Light Stability of a TiO2-Supported Porphyrinic Dye via Atomic Layer Deposition.

    PubMed

    Hoffeditz, William L; Son, Ho-Jin; Pellin, Michael J; Farha, Omar K; Hupp, Joseph T

    2016-12-21

    Organic and porphyrin-based chromophores are prevalent in liquid-junction photovoltaic and photocatalytic solar-cell chemistry; however, their long-term air and light instability may limit their practicality in real world technologies. Here, we describe the protection of a zinc porphyrin dye, adsorbed on nanoparticulate TiO2, from air and light degradation by a protective coating of alumina grown with a previously developed post-treatment atomic layer deposition (ALD) technique. The protective Al2O3 ALD layer is deposited using dimethylaluminum isopropoxide as an Al source; in contrast to the ubiquitous ALD precursor trimethylaluminum, dimethylaluminum isopropoxide does not degrade the zinc porphyrin dye, as confirmed by UV-vis measurements. The growth of this protective ALD layer around the dye can be monitored by an in-reactor quartz crystal microbalance (QCM). Furthermore, greater than 80% of porphyrin light absorption is retained over ∼1 month of exposure to air and light when the protective coating is present, whereas almost complete loss of porphyrin absorption is observed in less than 2 days in the absence of the ALD protective layer. Applying the Al2O3 post-treatment technique to the TiO2-adsorbed dye allows the dye to remain in electronic contact with both the semiconductor surface and a surrounding electrolyte solution, the combination of which makes this technique promising for numerous other electrochemical photovoltaic and photocatalytic applications, especially those involving the dye-sensitized evolution of oxygen.

  11. Insertion of a spin crossover Fe(III) complex into an oxalate-based layered material: coexistence of spin canting and spin crossover in a hybrid magnet.

    PubMed

    Clemente-León, Miguel; Coronado, Eugeno; Giménez-López, M Carmen; Soriano-Portillo, Alejandra; Waerenborgh, João C; Delgado, Fernando S; Ruiz-Pérez, Catalina

    2008-10-06

    The syntheses, structures, and magnetic properties of the compounds of formula [Fe (III)(sal 2trien)] 2[Mn (II) 2(ox) 3].4H 2O.C 3H 7NO ( 1) and [In (III)(sal 2trien)] 2[Mn (II) 2(ox) 3].3H 2O.CH 3OH (2) are reported. The structure presents a homometallic 2D honeycomb anionic layer formed by Mn (II) ions linked through oxalate ligands and a cationic double layer of [Fe(sal 2trien)] (+) or [In(sal 2trien)] (+) complexes intercalated between the 2D oxalate network. The magnetic properties and Mössbauer spectroscopy of 1 indicate the coexistence of a magnetic ordering of the Mn(II) oxalate network that behaves as a weak ferromagnet and a gradual spin crossover of the intercalated [Fe(sal 2trien)] (+) complexes.

  12. Mixed layers of β-lactoglobulin and SDS at air-water interfaces with tunable intermolecular interactions.

    PubMed

    Engelhardt, Kathrin; Weichsel, Ulrike; Kraft, Elena; Segets, Doris; Peukert, Wolfgang; Braunschweig, Björn

    2014-04-17

    Mixtures of β-lactoglobulin (BLG) and sodium dodecyl sulfate (SDS) were studied at pH 3.8 and 6.7 under equilibrium conditions. At these pH conditions, BLG carries either a positive or a negative net charge, respectively, which enables tunable electrostatic interactions between anionic SDS surfactants and BLG proteins. For pH 3.8, vibrational sum-frequency generation (SFG) and ellipsometry indicate strong BLG-SDS complex formation at air-water interfaces that is caused by attractive electrostatic interactions. The latter complexes are already formed in the bulk solution which was confirmed by a thermodynamic study of BLG-SDS mixtures using isothermal titration calorimetry (ITC). For acidic conditions we determine from our ITC data an exothermal binding enthalpy of -40 kJ mol(-1). Increasing SDS/BLG molar ratios above 10 leads to a surface excess of SDS and thus to a charge reversal from a positive net charge with BLG as the dominating surface adsorbed species to a negatively charged layer with SDS as the dominating surface species. The latter is evidenced by a pronounced minimum in SFG intensities that is also accompanied by a phase change of O-H stretching bands due to a reorientation of H2O within the local electric field. This phase change which occurs at SDS/BLG molar ratio between 1 and 10 causes a polarity change in SFG intensities from BLG aromatic C-H stretching vibrations. Conclusions from SFG spectra are corroborated by ellipsometry which shows a dramatic increase in layer thicknesses at molar ratios where a charge reversal occurs. The formation of interfacial multilayers comprising SDS-BLG complexes is, thus, caused by cancellation of electrostatic interactions which leads to agglomeration at the interface. In contrast to pH 3.8, behavior of BLG-SDS mixtures at pH 6.7 is different due to repulsive electrostatic interactions between SDS and BLG which lead to a significantly reduced binding enthalpy of -17 kJ mol(-1). Finally, it has to be mentioned that

  13. Preliminary investigation of the elemental variation and diagenesis of a tabular uranium deposit, La Sal Mine, San Juan County, Utah

    USGS Publications Warehouse

    Brooks, Robert A.; Campbell, John A.

    1976-01-01

    Ore in the La Sal mine, San Juan County, Utah, occurs as a typical tabular-type uranium deposit of the-Colorado Plateau. Uranium-vanadium occurs in the Salt Wash Member of the Jurassic Morrison Formation. Chemical and petrographic analyses were used to determine elemental variation and diagenetic aspects across the orebody. Vanadium is concentrated in the dark clay matrix, which constitutes visible ore. Uranium content is greater above the vanadium zone. Calcium, carbonate carbon, and lead show greater than fifty-fold increase across the ore zone, whereas copper and organic carbon show only a several-fold increase. Large molybdenum concentrations are present in and above the tabular layer, and large selenium concentrations occur below the uranium zone within the richest vanadium zone. Iron is enriched in the vanadium horizon. Chromium is depleted from above the ore and strongly enriched below. Elements that vary directly with the vanadium content include magnesium, iron, selenium, zirconium, strontium, titanium, lead, boron, yttrium, and scandium. The diagenetic sequence is as follows: (1) formation of secondary quartz overgrowths as cement; (2) infilling and lining of remaining pores with amber opaline material; (3) formation of vanadium-rich clay matrix, which has replaced overgrowths as well as quartz grains; (4) replacement of overgrowths and detrital grains by calcite; (5) infilling of pores with barite and the introduction of pyrite and marcasite.

  14. A modified SUnSAL-TV algorithm for hyperspectral unmixing based on spatial homogeneity analysis

    NASA Astrophysics Data System (ADS)

    Yuqian, Wang; Zhenfeng, Shao; Lei, Zhang; Weixun, Zhou

    2014-03-01

    The sparse regression framework has been introduced by many works to solve the linear spectral unmixing problem due to the knowledge that a pixel is usually mixed by less endmembers compared with the endmembers in spectral libraries or the entire hyperspectral data sets. Traditional sparse unmixing techniques focus on analyzing the spectral properties of hyperspectral imagery without incorporating spatial information. But the integration of spatial information would be beneficial to promote the performance of the linear unmixing process. An algorithm called sparse unmixing via variable splitting augmented Lagrangian and total variation (SUnSAL-TV) adds a total variation spatial regularizer besides the sparsity-inducing regularizer to the final unmixing objective function. The total variation spatial regularization is helpful to promote the fractional abundance smoothness. However, the abundance smoothness varies in the image. In this paper, the spatial smoothness is estimated through homogeneity analysis. Then the spatial regularizer is weighted for each pixel by a homogeneity index. The modified algorithm, called homogeneity analysis based SUnSAL-TV (SUnSAL-TVH), integrates the spatial information with finer modelling of spatial smoothness and is supposed insensitive to the noise and more stable. Experiments on synthetic data sets are taken and indicate the validity of our algorithm.

  15. Sal-Site: integrating new and existing ambystomatid salamander research and informational resources.

    PubMed

    Smith, Jeramiah J; Putta, Srikrishna; Walker, John A; Kump, D Kevin; Samuels, Amy K; Monaghan, James R; Weisrock, David W; Staben, Chuck; Voss, S Randal

    2005-12-16

    Salamanders of the genus Ambystoma are a unique model organism system because they enable natural history and biomedical research in the laboratory or field. We developed Sal-Site to integrate new and existing ambystomatid salamander research resources in support of this model system. Sal-Site hosts six important resources: 1) Salamander Genome Project: an information-based web-site describing progress in genome resource development, 2) Ambystoma EST Database: a database of manually edited and analyzed contigs assembled from ESTs that were collected from A. tigrinum tigrinum and A. mexicanum, 3) Ambystoma Gene Collection: a database containing full-length protein-coding sequences, 4) Ambystoma Map and Marker Collection: an image and database resource that shows the location of mapped markers on linkage groups, provides information about markers, and provides integrating links to Ambystoma EST Database and Ambystoma Gene Collection databases, 5) Ambystoma Genetic Stock Center: a website and collection of databases that describe an NSF funded salamander rearing facility that generates and distributes biological materials to researchers and educators throughout the world, and 6) Ambystoma Research Coordination Network: a web-site detailing current research projects and activities involving an international group of researchers. Sal-Site is accessible at http://www.ambystoma.org.

  16. 76 FR 9403 - Finding That the Lebanese Canadian Bank SAL Is a Financial Institution of Primary Money...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-17

    ... laundering network. Specifically, Ayman Joumaa deposits bulk cash into multiple exchange houses, including... Financial Crimes Enforcement Network Finding That the Lebanese Canadian Bank SAL Is a Financial Institution of Primary Money Laundering Concern AGENCY: Financial Crimes Enforcement Network, Treasury...

  17. D-SAL and NAP: Two Peptides Sharing a SIP Domain.

    PubMed

    Gozes, Illana; Sragovich, Shlomo; Schirer, Yulie; Idan-Feldman, Anat

    2016-06-01

    NAPVSIPQ (NAP) and all D-amino acid SALLRSIPA (D-SAL) are neuroprotective peptides derived from activity-dependent neuroprotective protein (ADNP) and activity-dependent neurotrophic factor (ADNF), respectively. Both proteins were shown to protect against cognitive impairment, using different animal models and to increase neuronal survival following exposure to neurotoxins. NAP was extensively tested and found to increase microtubule stability, protect axonal transport, and inhibit apoptosis. Here, we aimed to further evaluate and correlate effects at the behavioral level, in a rat model of diabetes. Diabetes is primarily a metabolic disorder which presents secondary neurological manifestations. Diabetes induces peripheral nervous system damage which is translated into impaired sensory perception and is termed diabetic neuropathy. Diabetes-related central nervous system damage causes cognitive decline. The behavioral study aimed to evaluate the effect of NAP and D-SAL on peripheral neuropathy and cognitive decline. Peripheral neuropathy was tested by measuring the response to a thermal stimulus, and cognitive ability was measured by a social memory test and a spatial memory test using long- and short-term dependent tasks and a reference memory task. Results indicated an immediate sensory neuropathy in the diabetic model, which was prevented by both peptides and a later neuropathic phase, prevented only by NAP treatment. Cognitive tests revealed impaired performance in both social and spatial memory tests in the diabetes model. Each of the peptides improved different aspects of cognitive behavior, with NAP being more potent than D-SAL. Mechanistically, both NAP and SAL contain a SIP (SxIP) domain that has been shown to interact with microtubule end-binding proteins (EBs). Specifically, we have previously shown a direct interaction of NAP with EB1 and EB3; we have further shown an interaction of the NAP-derived 4 amino acid SKIP peptide with EB3, stimulating axonal

  18. Determination of aflatoxins in air samples of refuse-derived fuel by thin-layer chromatography with laser-induced fluorescence spectrometric detection

    SciTech Connect

    Bicking, M.K.L.; Kniseley, R.N.; Svec, H.J.

    1983-02-01

    An analytical method is described which allows determination of aflatoxins in a complex matrix. An apparatus has been developed that quantitates fluorescent compounds on thin-layer chromatography plates. A nitrogen laser excitation source produces a detection limit of 10 pg for four aflatoxins. Aflatoxin B1 has been found at levels up to 17 ppb in solid samples collected from the air at a plant which produces refuse-derived fuel. 7 figures, 1 table.

  19. A Study of Cold-Air Modification over the Gulf of Mexico Using In Situ Data and Mixed-Layer Modeling.

    NASA Astrophysics Data System (ADS)

    Liu, Qingfu; Lewis, John M.; Schneider, Jeanne M.

    1992-08-01

    The evolution of the mean characteristics of the marine boundary layer during cold-air outbreaks can be described with an integrated or slab model. In order to assess the practical applicability of this-type of model to flows over the Gulf of Mexico, we use the observations collected during the Gulf of Mexico Experiment (GUFMEX) by an instrumented National Oceanic and Atmospheric Administration (NOAA) P-3 aircraft and a Cross-chain Loran Atmospheric Sounding System (CLASS) onboard the U.S. Coast Guard vessel Salvia. The numerical results show that the model successfully reproduced the changes in mean characteristics of momentum, moisture, and temperature under unstable conditions. The largest differences between the predictions and measurements are 0.8°C for the potential temperature, 0.15 g kg1 for the specific humidity, 47 m for the mixed-layer height, and 1.5 m s1 for the horizontal velocity components. A sensitivity analysis shows that the modeled mixed-layer height is slightly sensitive to changes in the specified sea surface temperature, while the other mean characteristics are relatively insensitive to the input parameters. Based upon the results of this single case study, the slab model appears to be a promising approach to account for the moistening and heating processes at the air-sea interface during cold-air outbreaks over the Gulf of Mexico.

  20. Improvement of performance in low temperature solid oxide fuel cells operated on ethanol and air mixtures using Cu-ZnO-Al2O3 catalyst layer

    NASA Astrophysics Data System (ADS)

    Morales, M.; Espiell, F.; Segarra, M.

    2015-10-01

    Anode-supported single-chamber solid oxide fuel cells with and without Cu-ZnO-Al2O3 catalyst layers deposited on the anode support have been operated on ethanol and air mixtures. The cells consist of gadolinia-doped ceria electrolyte, Ni-doped ceria anode, and La0.6Sr0.4CoO3-δ-doped ceria cathode. Catalyst layers with different Cu-ZnO-Al2O3 ratios are deposited and sintered at several temperatures. Since the performance of single-chamber fuel cells strongly depends on catalytic properties of electrodes for partial oxidation of ethanol, the cells are electrochemically characterized as a function of the temperature, ethanol-air molar ratio and gas flow rate. In addition, catalytic activities of supported anode, catalytic layer-supported anode and cathode for partial oxidation of ethanol are analysed. Afterwards, the effect of composition and sintering temperature of catalyst layer on the cell performance are determined. The results indicate that the cell performance can be significantly enhanced using catalyst layers of 30:35:35 and 40:30:30 wt.% Cu-ZnO-Al2O3 sintered at 1100 °C, achieving power densities above 50 mW cm-2 under 0.45 ethanol-air ratio at temperatures as low as 450 °C. After testing for 15 h, all cells present a gradual loss of power density, without carbon deposition, which is mainly attributed to the partial re-oxidation of Ni at the anode.

  1. Tailoring a compact and stable Langmuir bi-dimensional PbX-based layered perovskite film at the air-water interface and on solid support.

    PubMed

    Ariza-Carmona, Luisa; García-Espejo, Gonzalo; Martín-Romero, María T; Camacho, Luis

    2017-03-14

    The present work studies the stability of Langmuir organic-inorganic superlattice materials thin films consisting of layered perovskite-based films with controlled 2D framework as well as to design experimental conditions for increasing the efficiency of the organic-inorganic perovskite motif by mechanical stimulus. Therefore, a whole covering of the air/water interface by a compact and stable lead-based layered perovskite structure is pursued. A 2D layered perovskite-type hybrid structure of the form [(CH3(CH2)19NH3)2(PbX4)], X=Cl, and Br, in which, two-dimensional sheets stabilized by a inner bilayer of organic monoammonium cation matrix, is mechanically tailored by successive compression-expansion cycles. The formation of 2D molecular patterns has been characterized by ΔR, BAM, XRD and XPS.

  2. Observation studies on the influence of atmospheric boundary layer characteristics associate with air quality in dry season over the Pearl River Delta, China

    NASA Astrophysics Data System (ADS)

    Fan, Shaojia; Wu, Meng; Li, Haowen; Liao, Zhiheng; Fan, Qi; Zhu, Wei

    2016-04-01

    The characteristics of atmospheric boundary layer (ABL) is the very important factors influence on air quality in dry season over the Pearl River Delta (PRD), China. Based on the sounding data at six stations (Xinken,Dongguan, Sanshui, Nanhai, Shunde, and Heshan) which obtained from three times ABL experiments carried in dry season over PRD, the influence of wind and temperature vertical structure to the air quality over PRD has been studied with wind and temperature profiles, inversion layer, recirculation factor (RF), atmospheric boundary layer height (ABLH) and ventilation index (VI). It was found that the vertical wind of PRD could be divided in typical three layers according two wind shears appeared in 800 m and 1300 m. The thickness of calm or lower wind speed layer in pollution days was 500-1000m thicker than that of clean days, and its last time also much longer than that of clean days. The frequency of surface inversion in pollution days was about 35%,the mean thickness was about 100 m. With the influence of sea breeze, the frequency and thickness of surface inversion layer at Xinken station was a little lower than that in inland. Influenced by sea-land breezes and urban heat-island circulation, the RF of pollution days in coastal and urban area was quite smaller than that of clean days. During sea-land breezes days, the pollutants would be transported back to inland in nighttime with the influence of sea breeze, and resulted in 72.7% sea-land breezes was pollution days. The evolution of ABL was very typical in PRD during dry season. In pollution days, daily ABLH in PRD was lower than 500 m, daily VI was about 500-1500 m2/s. In clean days, daily VI was much larger than 2500 m2/s. An improved conceptual model of ABL influence on poor air quality and the parameters of the ABL characteristics associate with poor air quality in dry season over PRD had been summarized.

  3. Effect of a cold, dry air incursion on atmospheric boundary layer processes over a high-altitude lake in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Zhaoguo; Lyu, Shihua; Wen, Lijuan; Zhao, Lin; Ao, Yinhuan; Wang, Shaoying

    2017-03-01

    High-altitude lakes are frequently exposed to extreme meteorological conditions, but the surface and atmospheric boundary layer (ABL) processes have received little attention under specific weather conditions. This study used the multi-source field data, re-analysis and remote sensing data to investigate the varying patterns and driving forces of the convective boundary layer (CBL) height over Ngoring Lake in the Tibetan Plateau (TP) before and after the cold air incursion. Daily cumulative surface heat flux and buoyancy flux over the land were markedly larger than those over the lake on a clear summer day, but an opposite pattern was observed accompanied by the cold air incursion. CBLs determined by the potential temperature thinned (depth < 100 m) over the lake in the daytime and thickened (400-600 m) at night on a clear day. Along with the arrival of the cold air, CBL rapidly thickened to 2280 m over the lake, exceeded than the maximum value at adjacent Madoi station. Cold air dramatically cooled the middle-upper atmosphere but the temperature of the lower atmosphere cooled down slowly, partly due to a sharp increase of sensible heat flux over the lake, both of which linked up to weaken the potential temperature gradient. Moreover, increasing wind speed and vertical wind shear further facilitated the buoyancy flux to exert higher heat convection efficiency. All of these factors acted together to cause the rapid growth of CBL over the lake. This investigation provided a more in-depth knowledge of boundary layer dynamics in the lake-rich region of the TP.

  4. The performance of a two-layer biotrickling filter filled with new mixed packing materials for the removal of H2S from air.

    PubMed

    Chen, Yingwen; Wang, Xiaojun; He, Shuo; Zhu, Shemin; Shen, Shubao

    2016-01-01

    In the work described here, a two-layer biotrickling filter filled with new packing materials was used to remove H2S from air. The upper layer of the filter was packed with activated carbon-loaded polyurethane, whereas the lower layer was filled with modified organism-suspended fillers. The effects of inlet load, empty bed residence time (EBRT) from 79 s to 53 s, pH and contaminant starvation time were investigated. For loads of 15-50 g/(m(3) h), the average removal efficiency (RE) was higher than 96% under a consistent supply of pollutants. The critical elimination capacity was 39.95 g/(m(3) h) for an EBRT of 53 s with an RE of 99.9%. The two-layer BTF was capable of withstanding contaminant starvation periods for 1.5 d and 7 d with only a few hours of recovery time. The biodegradation kinetics was studied using Michaelis-Menten type equations under different EBRTs. At an EBRT of 66 s, the optimal kinetic constants rmax and Km were 333.3 g/(m(3) h) and 0.93 g/m(3), respectively. During the operation, the two-layer BTF performed well under various reasonable conditions.

  5. Effects of aggregates on mixed adsorption layers of poly(ethylene imine) and sodium dodecyl sulfate at the air/liquid interface.

    PubMed

    Tonigold, Katrin; Varga, Imre; Nylander, Tommy; Campbell, Richard A

    2009-04-07

    We have exploited the spatial and kinetic resolution of ellipsometry to monitor the lateral movement of inhomogeneous patches of material in mixed adsorption layers of poly(ethylene imine) and sodium dodecyl sulfate at the air/liquid interface. We show that the choice of sample preparation methods can have a profound effect on the state of the interface for chemically equivalent samples. The extent of aggregation in the bulk solution on relevant time scales is affected by specific details of the polymer/surfactant mixing process, which produces varying numbers of aggregates that can become trapped in the interfacial layer, resulting in an enhanced and fluctuating ellipsometry signal. It can be beneficial to apply the surface-cleaning method of aspiration prior to physical measurements to remove trapped aggregates through the creation of a fresh interface. At low pH, the ellipsometry signal of samples prepared with surface cleaning is remarkably constant over a factor of >500 in the bulk composition below charge equivalence, which is discussed in terms of possible adsorption mechanisms. At high pH, through observing temporal fluctuations in the ellipsometry signal of samples prepared with surface cleaning, we reveal two important processes: there is the spontaneous adsorption of aggregates > 0.2 microm in diameter into the interfacial layer, and with time there is the fusion of smaller aggregates to generate new large surface aggregates. We attribute the favorability of the adsorption and fusion processes at high pH to reduced electrostatic barriers resulting from the low surface charge density of the aggregates. It is inappropriate in this case to consider the interface to comprise a homogeneous adsorption layer that is in dynamic equilibrium with the bulk solution. Our work shows that it can be helpful to consider whether there are macroscopic particles embedded in molecular layers at the air/liquid interface for systems where there is prior knowledge of

  6. Aspects of the evolution of the marine boundary layer during cold-air outbreaks off the southeast coast of the United States

    NASA Technical Reports Server (NTRS)

    Vukovich, Fred M.; Dunn, J. W.; Crissman, Bobby W.

    1991-01-01

    Remote sensing and in situ measurements that were obtained in February 1986 were combined with the results from a boundary-layer model to study aspects of the evolution of the maine boundary layer (MBL) during two cold-air outbreaks (CAO) off the southeast coast of the United States. Maximum total heat fluxes occurred over the Gulf Stream northeast of Cape Hatteras where very cold, dry air encountered the Gulf Stream and where the wind speeds were very large. Maximum 6-h values for the total heat flux were as high as 2015 W/m. The magnitude of the area-average heat flux in the MBL was influenced not only by the surface air and dewpoint temperatures and the surface wind speeds off the coast but also by the area covered by Gulf Stream water (sea surface temperature greater than 22 C). The heat flux distribution off the coast rapidly produced large horizontal temperature and humidity differences over distances on the order of 100 km.

  7. Chemical signatures of aged Pacific marine air: Mixed layer and free troposphere as measured during PEM-West A

    NASA Astrophysics Data System (ADS)

    Gregory, G. L.; Bachmeier, A. S.; Blake, D. R.; Heikes, B. G.; Thornton, D. C.; Bandy, A. R.; Bradshaw, J. D.; Kondo, Y.

    1996-01-01

    The Pacific Ocean is one of the few remaining regions of the northern hemisphere that is relatively free of direct anthropogenic emissions. However, long-range transport of air pollutants is beginning to have a significant impact on the atmosphere over the Pacific. In September and October 1991, NASA conducted the Pacific Exploratory Mission-West A expedition to study the atmospheric chemistry and background budgets of key atmospheric trace species. Aircraft sampling centered on the northern Pacific, 0° to 40°N and 115° to 180°E. The paper summarizes the chemical signature of relatively well-aged Pacific marine air (residence time ≥10 days over the ocean). The chemical signatures show that marine air is not always devoid of continental influences. Aged marine air which circulates around the semipermanent subtropical anticyclone located off the Asian continent is influenced by infusion of continental air with anthropogenic emissions. The infusion occurs as the result of Asian outflow swept off the continent behind eastward moving cold fronts. When compared to aged marine air with a more southerly pathway, this infusion results in enhancements in the mixing ratio of many anthropogenic/continental species and typically those with lifetimes of weeks in the free troposphere. Less enhancement is seen for the short-lived species with lifetimes of a few days as infused continental emissions are depleted during transport (about a week) around the semipermanent subtropical high.

  8. Elemental evolution of the SiOxFy self-masking layer of plasma textured silicon and its modification during air exposure

    NASA Astrophysics Data System (ADS)

    Gaudig, Maria; Hirsch, Jens; Naumann, Volker; Werner, Martina; Großer, Stephan; Hagendorf, Christian; Bernhard, Norbert; Lausch, Dominik

    2017-02-01

    The influence of the SiOxFy selfmasking process on the formation of black-Silicon (b-Si) textures by maskless SF6/O2 plasma etching is of great interest with regard to the optimization of the texturing process for highly antireflective silicon. For that reason, the elemental composition of plasma textured silicon surfaces is analyzed by transmission electron microscopy and X-ray photoelectron spectroscopy. The chemical composition of a fluorine containing oxide layer on top of the surface was confirmed and determined quantitatively. A strongly reduced F content was found after ambient air exposure. A qualitative model of the chemical and physical processes caused by maskless plasma texturing was developed to explain the observed experimental results. The decrease in the F content is assumed to be caused by hydrolysis of F by air moisture, resulting in a successive desorption of HF and transformation of SiOxFy to silicon oxide.

  9. A Numerical Study of Tropical Sea-Air Interactions Using a Cloud Resolving Model Coupled with an Ocean Mixed-Layer Model

    NASA Technical Reports Server (NTRS)

    Shie, Chung-Lin; Tao, Wei-Kuo; Johnson, Dan; Simpson, Joanne; Li, Xiaofan; Sui, Chung-Hsiung; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Coupling a cloud resolving model (CRM) with an ocean mixed layer (OML) model can provide a powerful tool for better understanding impacts of atmospheric precipitation on sea surface temperature (SST) and salinity. The objective of this study is twofold. First, by using the three dimensional (3-D) CRM-simulated (the Goddard Cumulus Ensemble model, GCE) diabatic source terms, radiation (longwave and shortwave), surface fluxes (sensible and latent heat, and wind stress), and precipitation as input for the OML model, the respective impact of individual component on upper ocean heat and salt budgets are investigated. Secondly, a two-way air-sea interaction between tropical atmospheric climates (involving atmospheric radiative-convective processes) and upper ocean boundary layer is also examined using a coupled two dimensional (2-D) GCE and OML model. Results presented here, however, only involve the first aspect. Complete results will be presented at the conference.

  10. Forced Boundary-Layer Transition on X-43 (Hyper-X) in NASA LaRC 20-Inch Mach 6 Air Tunnel

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; DiFulvio, Michael; Kowalkowski, Matthew K.

    2000-01-01

    Aeroheating and boundary layer transition characteristics for the X-43 (Hyper-X) configuration have been experimentally examined in the Langley 20-Inch Mach 6 Air Tunnel. Global surface heat transfer distributions, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles-of-attack of 0-deg, 2-deg, and 4-deg; Reynolds numbers based on model length of 1.2 to 15.4 million; and inlet cowl door both open and closed. The effects of discrete roughness elements on the forebody boundary layer, which included variations in trip configuration and height, were investigated. This document is intended to serve as a release of preliminary data to the Hyper-X program; analysis is limited to observations of the experimental trends in order to expedite dissemination.

  11. Forced Boundary-Layer Transition on X-43 (Hyper-X) in NASA LaRC 31-Inch Mach 10 Air Tunnel

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; DiFulvio, Michael; Kowalkowski, Matthew K.

    2000-01-01

    Aeroheating and boundary layer transition characteristics for the X-43 (Hyper-X) configuration have been experimentally examined in the Langley 31-Inch Mach 10 Air Tunnel. Global surface heat transfer distributions, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles-of-attack of 0-deg, 2-deg, 3-deg, and 4-deg; Reynolds numbers based on model length of 1.2 to 5.1 million; and inlet cowl door both open and closed. The effects of discrete roughness elements on the forebody boundary layer, which included variations in trip configuration and height, were investigated. This document is intended to serve as a release of preliminary data to the Hyper-X program; analysis is limited to observations of the experimental trends in order to expedite dissemination.

  12. Heat and mass transfer in a dissociated laminar boundary layer of air with consideration of the finite rate of chemical reaction

    NASA Technical Reports Server (NTRS)

    Oyegbesan, A. O.; Algermissen, J.

    1986-01-01

    A numerical investigation of heat and mass transfer in a dissociated laminar boundary layer of air on an isothermal flat plate is carried out for different degrees of cooling of the wall. A finite-difference chemical model is used to study elementary reactions involving NO2 and N2O. The analysis is based on equations of continuity, momentum, energy, conservation and state for the two-dimensional viscous flow of a reacting multicomponent mixtures. Attention is given to the effects of both catalyticity and noncatalyticity of the wall.

  13. Infrared spectroscopy analysis of mixed DPPC/fibrinogen layer behavior at the air/liquid interface under a continuous compression-expansion condition.

    PubMed

    Yin, Chia-Lin; Chang, Chien-Hsiang

    2006-07-18

    The mixed layer behavior of dipalmitoyl phosphatidylcholine (DPPC) with fibrinogen at continuously compressed-expanded air/liquid interfaces was analyzed in situ by infrared reflection-absorption spectroscopy (IRRAS). The reflectance-absorbance (RA) intensities and/or wavenumbers of nu(a)-CH2 and amide I bands for a mixed DPPC/fibrinogen layer at the interface were obtained directly by an infrared spectrometer with a monolayer/grazing angle accessory and a removable Langmuir trough. The nu(a)-CH2 RA intensity-area hysteresis curves of a DPPC monolayer indicate a significant loss of free DPPC molecules at the interface during the first compression stage, which is also supported by the corresponding nu(a)-CH2 wavenumber-area hysteresis curves. For a mixed DPPC/fibrinogen layer at the interface, the amide I RA intensity-area hysteresis curves suggest that the fibrinogen molecules were expelled from the interface upon compression, apparently because of the presence of insoluble DPPC molecules. The squeeze-out of fibrinogen evidently removed a pronounced amount of DPPC from the interface, as judged from the corresponding nu(a)-CH2 intensity and wavenumber data. Moreover, significant adsorption of fibrinogen was found during the subsequent interface expansion stage. With the in situ IRRAS analysis of the mixed layer behavior at the interface, the induced loss of DPPC by fibrinogen expulsion from the compressed interface and the dominant adsorption of fibrinogen to the expanded interface were clearly demonstrated.

  14. An Effective On-line Polymer Characterization Technique by Using SALS Image Processing Software and Wavelet Analysis

    PubMed Central

    Xian, Guang-ming; Qu, Jin-ping; Zeng, Bi-qing

    2008-01-01

    This paper describes an effective on-line polymer characterization technique by using small-angle light-scattering (SALS) image processing software and wavelet analysis. The phenomenon of small-angle light scattering has been applied to give information about transparent structures on morphology. Real-time visualization of various scattered light image and light intensity matrices is performed by the optical image real-time processing software for SALS. The software can measure the signal intensity of light scattering images, draw the frequency-intensity curves and the amplitude-intensity curves to indicate the variation of the intensity of scattered light in different processing conditions, and estimate the parameters. The current study utilizes a one-dimensional wavelet to delete noise from the original SALS signal and estimate the variation trend of maximum intensity area of the scattered light. So, the system brought the qualitative analysis of the structural information of transparent film success. PMID:19229343

  15. Freezing Fog Formation in a Supercooled Boundary Layer: Solving the Winter Fog Forecasting Challenge for Elmendorf Air Force Base, Alaska

    DTIC Science & Technology

    2007-03-01

    vicinity of the base are a wide variety of streams, small lakes and tundra , with large trees along some streams in the valley. The largest stream in the...and dry cA air mass move in from 15 the northwest associated with a Siberian High, while a much warmer and moister mP air mass would move in from...a Siberian High and a Gulf of Alaska Low at the start of the fog event. The low pressure center was nearly 400NM southeast of the base with an

  16. Aerosol-cloud-precipitation interactions in the trade wind boundary layer

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil

    This dissertation includes an overview of aerosol, cloud, and precipitation properties associated with shallow marine cumulus clouds observed during the Barbados Aerosol Cloud Experiment (BACEX, March-April 2010) and a discussion of their interactions. The principal observing platform for the experiment was the Cooperative Institute for Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter (TO) research aircraft that was equipped with aerosol, cloud, and precipitation probes, standard meteorological instruments, and a up-looking cloud radar. The temporal variations and vertical distributions of aerosols observed on the 15 flights show a wide range of aerosol conditions that include the most intense African dust event observed at the Barbados surface site during all of 2010. An average CCN varied from 50 cm-3 to 800 cm -3 at super-saturation of 0.6 %, for example. The 10-day backward trajectories show that three distinctive air masses (originality of air mass as well as the vertical structure) dominate over the Eastern Caribbean (e.g., typical maritime air mass, Saharan Air Layer (SAL), Middle latitude dry air) with characteristic aerosol vertical structures. Many clouds in various phases of growth during BACEX are sampled. The maximum cloud depth observed is about less than 3 km and in most of the clouds is less than 1 km. Two types of precipitation features were observed for the shallow marine cumulus clouds with different impacts on boundary layer. In one, precipitation shafts are observed to emanate from the cloud base with evaporation in the sub-cloud layer (stabilize the sub-cloud layer). In the other, precipitation shafts emanate mainly near the cloud top on the downshear side of the cloud and evaporate in the cloud layer, leading to destabilizing the cloud layer and providing moisture to the layer. Only 42-44 % of clouds sampled were purely non-precipitating throughout the clouds; the remainder of the clouds showed precipitation somewhere in the cloud

  17. Efficient, air-stable colloidal quantum dot solar cells encapsulated using atomic layer deposition of a nanolaminate barrier

    SciTech Connect

    Ip, Alexander H.; Labelle, André J.; Sargent, Edward H.

    2013-12-23

    Atomic layer deposition was used to encapsulate colloidal quantum dot solar cells. A nanolaminate layer consisting of alternating alumina and zirconia films provided a robust gas permeation barrier which prevented device performance degradation over a period of multiple weeks. Unencapsulated cells stored in ambient and nitrogen environments demonstrated significant performance losses over the same period. The encapsulated cell also exhibited stable performance under constant simulated solar illumination without filtration of harsh ultraviolet photons. This monolithically integrated thin film encapsulation method is promising for roll-to-roll processed high efficiency nanocrystal solar cells.

  18. An examination of boundary layer structure under the influence of the gap winds in Urumqi, China, during air pollution episode in winter.

    PubMed

    Li, Xia; Xia, Xiangao; Xin, Yu; Ma, Yufen; Yang, Jing; Li, Jinglin; Yang, Xinghua

    2012-01-01

    Tethered-sonde measurements of atmospheric profiles were performed at Urumuqi, capital of the Xinjiang Uyghur Autonomous Region of China, from 29 December 2008 to 14 January 2009. The data were used to examine the boundary layer structure during this severe air pollution period. Diurnal evolution of local wind flow near Urumqi was simulated using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5). Measurements from operational radiosonde data showed that a southeasterly elevated low-level jet often intruded upon Urumqi through the middle Tianshan Mountain pass to the south of the city. The tethered-sonde measurements showed that calm and northwesterly winds prevailed near the surface in Urumqi, whereas the southeasterly winds of relatively higher speed were dominant above approximately 400 m. Both temperature inversion and humidity inversion frequently occured during day and nighttime. Temperature inversion intensity could sharply rise as the stronger elevated southeasterly gale (ESEG) happened. Model simulations showed that the winds near the surface around Urumqi remained calm during nighttime and developed toward the mountains during daytime. As cool airflow in the basin confronted the southeasterly winds from the pass in the lower layer, they formed a convergence line around Urumqi city, which was not favor for dilution of air pollutants.

  19. The China Clipper - Fast advective transport of radon-rich air from the Asian boundary layer to the upper troposphere near California

    NASA Technical Reports Server (NTRS)

    Kritz, Mark A.; Le Roulley, Jean-Claude; Danielsen, Edwin F.

    1990-01-01

    A series of upper tropospheric radon concentration measurements made over the eastern Pacific and west coast of the U.S. during the summers of 1983 and 1984 has revealed the occurrence of unexpectedly high radon concentrations for 9 of the 61 measurements. A frequency distribution plot of the set of 61 observations shows a distinct bimodal distribution, with approximately 2/5 of the observations falling close to 1 pCi/SCM, and 3/5 falling in a high concentration mode centered at about 11 pCi/SCM. Trajectory and synoptic analyses for two of the flights on which such high radon concentrations were observed indicate that this radon-rich air originated in the Asian boundary layer, ascended in cumulus updrafts, and was carried eastward in the fast moving air on the anticyclonic side of the upper tropospheric jet. The results suggest that the combination of rapid vertical transport from the surface boundary layer to the upper troposphere, followed by rapid horizontal transport eastward represents an efficient mode of long-transport for other, chemically reactive atmospheric trace constituents.

  20. Mechanical properties of protein adsorption layers at the air/water and oil/water interface: a comparison in light of the thermodynamical stability of proteins.

    PubMed

    Mitropoulos, Varvara; Mütze, Annekathrin; Fischer, Peter

    2014-04-01

    Over the last decades numerous studies on the interfacial rheological response of protein adsorption layers have been published. The comparison of these studies and the retrieval of a common parameter to compare protein interfacial activity are hampered by the fact that different boundary conditions (e.g. physico-chemical, instrumental, interfacial) were used. In the present work we review previous studies and attempt a unifying approach for the comparison between bulk protein properties and their adsorption films. Among many common food grade proteins we chose bovine serum albumin, β-lactoglobulin and lysozyme for their difference in thermodynamic stability and studied their adsorption at the air/water and limonene/water interface. In order to achieve this we have i) systematically analyzed protein adsorption kinetics in terms of surface pressure rise using a drop profile analysis tensiometer and ii) we addressed the interfacial layer properties under shear stress using an interfacial shear rheometer under the same experimental conditions. We could show that thermodynamically less stable proteins adsorb generally faster and yield films with higher shear rheological properties at air/water interface. The same proteins showed an analog behavior when adsorbing at the limonene/water interface but at slower rates.

  1. Experimental determination of the boundary layer at air-sample inlet positions on the NASA CV 990 aircraft

    NASA Technical Reports Server (NTRS)

    Bowen, S. W.; Vedder, J. F.; Condon, E. P.

    1984-01-01

    Full-scale, in-flight measurements of the boundary-layer thickness, velocity profile, and flow angle have been made at several sample collection stations on the fuselage of the NASA CV 990. These results are given as functions of Mach number, Reynolds number, yaw, and angle of attack.

  2. Efficient, Air-Stable Bulk Heterojunction Polymer Solar Cells Using MoOx as the Anode Interfacial Layer

    SciTech Connect

    Sun, Yanming; Takacs, Christopher J.; Cowan, Sarah R.; Seo, Jung Hwa; Gong, Xiong; Roy, Anshuman; Heeger, Alan J.

    2011-04-05

    The use of molybdenum oxide as the anode interfacial layer in conventional bulk heterojunction polymer solar cells leads to an improved power conversion efficiency and also dramatically increases the device stability. This indicates that the engineering of improved anode interface materials is an important method by which to fabricate efficient and stable polymer solar cells.

  3. A controlling role for the air-sea interface in the chemical processing of reactive nitrogen in the coastal marine boundary layer.

    PubMed

    Kim, Michelle J; Farmer, Delphine K; Bertram, Timothy H

    2014-03-18

    The lifetime of reactive nitrogen and the production rate of reactive halogens in the marine boundary layer are strongly impacted by reactions occurring at aqueous interfaces. Despite the potential importance of the air-sea interface in serving as a reactive surface, few direct field observations are available to assess its impact on reactive nitrogen deposition and halogen activation. Here, we present direct measurements of the vertical fluxes of the reactant-product pair N2O5 and ClNO2 to assess the role of the ocean surface in the exchange of reactive nitrogen and halogens. We measure nocturnal N2O5 exchange velocities (Vex = -1.66 ± 0.60 cm s(-1)) that are limited by atmospheric transport of N2O5 to the air-sea interface. Surprisingly, vertical fluxes of ClNO2, the product of N2O5 reactive uptake to concentrated chloride containing surfaces, display net deposition, suggesting that elevated ClNO2 mixing ratios found in the marine boundary layer are sustained primarily by N2O5 reactions with aerosol particles. Comparison of measured deposition rates and in situ observations of N2O5 reactive uptake to aerosol particles indicates that N2O5 deposition to the ocean surface accounts for between 26% and 42% of the total loss rate. The combination of large Vex, N2O5 and net deposition of ClNO2 acts to limit NOx recycling rates and the production of Cl atoms by shortening the nocturnal lifetime of N2O5. These results indicate that air-sea exchange processes account for as much as 15% of nocturnal NOx removal in polluted coastal regions and can serve to reduce ClNO2 concentrations at sunrise by over 20%.

  4. Hygroscopic Growth of Self-Assembled Layered Surfactant Molecules at the Interface between Air and Organic Salts

    SciTech Connect

    Shin, Yongsoon; Wang, Li Q.; Fryxell, Glen E.; Exarhos, Gregory J.; Lu, Yunfeng

    2003-12-15

    In this paper, we report a self-assembly of surfactant molecules at the interface of air/hygroscopic quaternary ammonium salts such as tetrabutylammonium acetate (TBAAc), tetrabutylammonium bromide (TBAB), and tetrabutylammonium nitrate (TBAN), where they show different hygroscopicity, TBAAc > TBAB TBAN. Homogeneously dissolved surfactants rearrange themselves when they contact air due to high moisture adsorption behavior of such organic salts. Highly ordered lamellar phases with different lattice spacings have been observed when surfactants with long alkyl chains were used. Alkylammonium halides form monolayers, while neutral alkylamines forms bilayers based upon basal spacings of their X-ray diffraction patterns. The change in basal spacings in lamellar patterns, the alkyl chain conformation of surfactants, and H-bonding property of neutral amine surfactants are discussed in detail.

  5. Effect of weave tightness and structure on the in-plane and through-plane air permeability of woven carbon fibers for gas diffusion layers

    NASA Astrophysics Data System (ADS)

    Caston, Terry B.; Murphy, Andrew R.; Harris, Tequila A. L.

    In this study, woven gas diffusion layers (GDLs) with varying weave type and tightness are investigated. Plain and twill weave patterns were manufactured in-house. The in-plane and through-plane air permeability of the woven samples were tested, and mercury intrusion porosimetry (MIP) tests were performed to study the pore structure. It was found that the twill weave has a higher permeability than the plain weave, which is consistent with literature. Like non-woven carbon papers, woven GDLs have higher in-plane permeability than through-plane permeability; however it has been shown that it is possible to manufacture a GDL with higher through-plane permeability than in-plane permeability. It was also concluded that the percentage of macropores in the weave is the driving factor in determining the through-plane air permeability. This work lays the groundwork for future studies to attempt to characterize the relationship between the weave structure and the air permeability in woven GDLs.

  6. Investigation of the Hosgri Fault, offshore Southern California, Point Sal to Point Conception

    USGS Publications Warehouse

    Payne, C.M.; Swanson, O.E.; Schell, B.A.

    1979-01-01

    A high-resolution seismic reflection survey of the inner continental shelf between Point Sal and Point Conception has revealed faults that displace post-Wisconsin strata (less than 17,000-20,000 years). These faults are the Hosgri fault, the Offshore Lompoc fault, and smaller unnamed faults. Faults trending offshore from the adjacent shoreline such as the Pezzoni, Lions Head, Honda, and Pacifico faults, do not show post-Wisconsin activity. The Hosgri fault trends directly toward the coastline between Purisima Point and Point Arguello where it appears to merge with folds and smaller faults in the western Transverse Ranges. This trend of offshore structures toward the Point Arguello-Point Conception area is consistent with a hypothesis that the regional structural fabric of the southern California Coast Ranges and its adjacent offshore area merge with the Transverse Ranges.

  7. Insights into an Optimization of Plasmodium vivax Sal-1 In Vitro Culture: The Aotus Primate Model.

    PubMed

    Shaw-Saliba, Kathryn; Thomson-Luque, Richard; Obaldía, Nicanor; Nuñez, Marlon; Dutary, Sahir; Lim, Caeul; Barnes, Samantha; Kocken, Clemens H M; Duraisingh, Manoj T; Adams, John H; Pasini, Erica M

    2016-07-01

    Malaria is one of the most significant tropical diseases, and of the Plasmodium species that cause human malaria, P. vivax is the most geographically widespread. However, P. vivax remains a relatively neglected human parasite since research is typically limited to laboratories with direct access to parasite isolates from endemic field settings or from non-human primate models. This restricted research capacity is in large part due to the lack of a continuous P. vivax in vitro culture system, which has hampered the ability for experimental research needed to gain biological knowledge and develop new therapies. Consequently, efforts to establish a long-term P. vivax culture system are confounded by our poor knowledge of the preferred host cell and essential nutrients needed for in vitro propagation. Reliance on very heterogeneous P. vivax field isolates makes it difficult to benchmark parasite characteristics and further complicates development of a robust and reliable culture method. In an effort to eliminate parasite variability as a complication, we used a well-defined Aotus-adapted P. vivax Sal-1 strain to empirically evaluate different short-term in vitro culture conditions and compare them with previous reported attempts at P. vivax in vitro culture Most importantly, we suggest that reticulocyte enrichment methods affect invasion efficiency and we identify stabilized forms of nutrients that appear beneficial for parasite growth, indicating that P. vivax may be extremely sensitive to waste products. Leuko-depletion methods did not significantly affect parasite development. Formatting changes such as shaking and static cultures did not seem to have a major impact while; in contrast, the starting haematocrit affected both parasite invasion and growth. These results support the continued use of Aotus-adapted Sal-1 for development of P. vivax laboratory methods; however, further experiments are needed to optimize culture conditions to support long-term parasite

  8. Insights into an Optimization of Plasmodium vivax Sal-1 In Vitro Culture: The Aotus Primate Model

    PubMed Central

    Obaldía, Nicanor; Nuñez, Marlon; Dutary, Sahir; Lim, Caeul; Barnes, Samantha; Kocken, Clemens H. M.; Duraisingh, Manoj T.; Adams, John H.; Pasini, Erica M.

    2016-01-01

    Malaria is one of the most significant tropical diseases, and of the Plasmodium species that cause human malaria, P. vivax is the most geographically widespread. However, P. vivax remains a relatively neglected human parasite since research is typically limited to laboratories with direct access to parasite isolates from endemic field settings or from non-human primate models. This restricted research capacity is in large part due to the lack of a continuous P. vivax in vitro culture system, which has hampered the ability for experimental research needed to gain biological knowledge and develop new therapies. Consequently, efforts to establish a long-term P. vivax culture system are confounded by our poor knowledge of the preferred host cell and essential nutrients needed for in vitro propagation. Reliance on very heterogeneous P. vivax field isolates makes it difficult to benchmark parasite characteristics and further complicates development of a robust and reliable culture method. In an effort to eliminate parasite variability as a complication, we used a well-defined Aotus-adapted P. vivax Sal-1 strain to empirically evaluate different short-term in vitro culture conditions and compare them with previous reported attempts at P. vivax in vitro culture Most importantly, we suggest that reticulocyte enrichment methods affect invasion efficiency and we identify stabilized forms of nutrients that appear beneficial for parasite growth, indicating that P. vivax may be extremely sensitive to waste products. Leuko-depletion methods did not significantly affect parasite development. Formatting changes such as shaking and static cultures did not seem to have a major impact while; in contrast, the starting haematocrit affected both parasite invasion and growth. These results support the continued use of Aotus-adapted Sal-1 for development of P. vivax laboratory methods; however, further experiments are needed to optimize culture conditions to support long-term parasite

  9. Senstitivity analysis of horizontal heat and vapor transfer coefficients for a cloud-topped marine boundary layer during cold-air outbreaks. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Chang, Y. V.

    1986-01-01

    The effects of external parameters on the surface heat and vapor fluxes into the marine atmospheric boundary layer (MABL) during cold-air outbreaks are investigated using the numerical model of Stage and Businger (1981a). These fluxes are nondimensionalized using the horizontal heat (g1) and vapor (g2) transfer coefficient method first suggested by Chou and Atlas (1982) and further formulated by Stage (1983a). In order to simplify the problem, the boundary layer is assumed to be well mixed and horizontally homogeneous, and to have linear shoreline soundings of equivalent potential temperature and mixing ratio. Modifications of initial surface flux estimates, time step limitation, and termination conditions are made to the MABL model to obtain accurate computations. The dependence of g1 and g2 in the cloud topped boundary layer on the external parameters (wind speed, divergence, sea surface temperature, radiative sky temperature, cloud top radiation cooling, and initial shoreline soundings of temperature, and mixing ratio) is studied by a sensitivity analysis, which shows that the uncertainties of horizontal transfer coefficients caused by changes in the parameters are reasonably small.

  10. Thin air-plasma-treated alkali fluoride layers for improved hole extraction in copper phthalocyanine/C70-based solar cells

    SciTech Connect

    Xiao, Teng; Cui, Weipan; Cai, Min; Liu, Rui; Anderegg, James W.; Shinar, Joseph; Shinar, Ruth

    2012-03-12

    Alkali fluorides, mostly LiF and CsF, are well-known to improve electron injection/extraction in organic light-emitting diodes (OLEDs) and organic solar cells (OSCs). They are also utilized, though to a lesser extent, for hole injection in OLEDs. Here we demonstrate a new role for such fluorides in enhancing OSCs’ hole extraction.We show that an ultrathin air-plasmatreated alkali fluoride layer between the indium tin oxide (ITO) anode and the active layer in copper phthalocyanine ðCuPcÞ∕C70-based OSCs increases the short circuit current by up to ∼17% for cells with LiF and ∼7% for cells with NaF or CsF. The effects of the fluoride layer thickness and treatment duration were evaluated, as were OSCs with oxidized and plasma-treated Li and UV-ozone treated LiF. Measurements included current voltage, absorption, external quantum efficiency (EQE), atomic force microscopy, and x-ray photoelectron spectroscopy, which showed the presence of alkali atoms F and O at the treated ITO/fluoride surface. The EQE of optimized devices with LiF increased at wavelengths >560 nm, exceeding the absorption increase. Overall, the results indicate that the improved performance is due largely to enhanced hole extraction, possibly related to improved energy-level alignment at the fluorinated ITO/CuPc interface, reduced OSC series resistance, and in the case of LiF, improved absorption.

  11. The Turbulent Boundary Layer Near the Air-Water Interface on a Surface-Piercing Flat Plate

    NASA Astrophysics Data System (ADS)

    Washuta, Nathan; Masnadi, Naeem; Duncan, James H.

    2015-11-01

    Turbulent fluctuations in the vicinity of the water free surface along a flat, vertically oriented surface-piercing plate are studied experimentally using a laboratory-scale experiment. In this experiment, a meter-wide stainless steel belt travels horizontally in a loop around two rollers with vertically oriented axes, which are separated by 7.5 meters. This belt device is mounted inside a large water tank with the water level set just below the top edge of the belt. The belt, rollers, and supporting frame are contained within a sheet metal box to keep the device dry except for one 6-meter-long straight test section between rollers. The belt is launched from rest with a 3- g acceleration in order to quickly reach steady state velocity. This creates a temporally evolving boundary layer analogous to the spatially evolving boundary layer created along a flat-sided ship moving at the same velocity, with a length equivalent to the length of belt that has passed the measurement region since the belt motion began. Cinematic Stereo PIV measurements are performed in planes parallel to the free surface by imaging the flow from underneath the tank in order to study the modification of the boundary layer flow field due to the effects of the water free surface. The support of the Office of Naval Research under grant N000141110029 is gratefully acknowledged.

  12. Hepatoprotective Activity of Herbal Composition SAL, a Standardize Blend Comprised of Schisandra chinensis, Artemisia capillaris, and Aloe barbadensis.

    PubMed

    Yimam, Mesfin; Jiao, Ping; Moore, Breanna; Hong, Mei; Cleveland, Sabrina; Chu, Min; Jia, Qi; Lee, Young-Chul; Kim, Hyun-Jin; Nam, Jeong-Bum; Kim, Mi-Ran; Hyun, Eu-Jin; Jung, Gayoung; Do, Seon Gil

    2016-01-01

    Some botanicals have been reported to possess antioxidative activities acting as scavengers of free radicals rendering their usage in herbal medicine. Here we describe the potential use of "SAL," a standardized blend comprised of three extracts from Schisandra chinensis, Artemisia capillaris, and Aloe barbadensis, in mitigating chemically induced acute liver toxicities. Acetaminophen and carbon tetrachloride induced acute liver toxicity models in mice were utilized. Hepatic functional tests from serum collected at T24 and hepatic glutathione and superoxide dismutases from liver homogenates were evaluated. Histopathology analysis and merit of blending 3 standardized extracts were also confirmed. Statistically significant and dose-correlated inhibitions in serum ALT ranging from 52.5% (p = 0.004) to 34.6% (p = 0.05) in the APAP and 46.3% (p < 0.001) to 29.9% (p = 0.02) in the CCl4 models were observed for SAL administered at doses of 400-250 mg/kg. Moreover, SAL resulted in up to 60.6% and 80.2% reductions in serums AST and bile acid, respectively. The composition replenished depleted hepatic glutathione in association with an increase of hepatic superoxide dismutase. Unexpected synergistic protection from liver damage was also observed. Therefore, the composition SAL could be potentially utilized as an effective hepatic-detoxification agent for the protection from liver damage.

  13. Nonlinear rheology of CTAB/NaSal aqueous solutions: finite extensibility of a network of wormlike micelles.

    PubMed

    Inoue, Tadashi; Inoue, Yoshitaka; Watanabe, Hiroshi

    2005-02-15

    The nonlinear rheology of aqueous solutions of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) was investigated. The concentration of CTAB was fixed at 0.1 mol L(-1), and the concentration of NaSal was varied from 0.07 to 0.4 mol L(-1). For all test solutions, dynamic moduli were described with the Maxwell model having a single relaxation time, tau. Time evolutions of the shear stress, sigma, and the first normal stress difference, N(1), after inception of the steady shear flow were measured. For solutions having low NaSal concentrations, strain-hardening was observed and sigma and N(1) diverged at a certain strain when the shear rate, , exceeded tau(-1). For solutions with high NaSal concentrations, stress overshoot similar to that of ordinary entangled polymer solutions was observed at between tau(-1) and a certain critical rate, (C), while the strain-hardening was observed at > (C). A simple relationship for elastic solids, N(1)/sigma = gamma with gamma being the strain imposed by shear flow, held for all the solutions in the strain-hardening regime. The strain-hardening was attributable to the strain-dependent shear modulus and well described with the network theory considering the finite extensibility of network strands. The segment size of network strands was successfully determined. Thus, the stress-strain relationship obtained after the inception of fast flows is useful for characterizing the network properties.

  14. Hepatoprotective Activity of Herbal Composition SAL, a Standardize Blend Comprised of Schisandra chinensis, Artemisia capillaris, and Aloe barbadensis

    PubMed Central

    Yimam, Mesfin; Jiao, Ping; Moore, Breanna; Hong, Mei; Cleveland, Sabrina; Chu, Min; Jia, Qi; Lee, Young-Chul; Kim, Hyun-Jin; Nam, Jeong-Bum; Kim, Mi-Ran; Hyun, Eu-Jin; Jung, Gayoung; Do, Seon Gil

    2016-01-01

    Some botanicals have been reported to possess antioxidative activities acting as scavengers of free radicals rendering their usage in herbal medicine. Here we describe the potential use of “SAL,” a standardized blend comprised of three extracts from Schisandra chinensis, Artemisia capillaris, and Aloe barbadensis, in mitigating chemically induced acute liver toxicities. Acetaminophen and carbon tetrachloride induced acute liver toxicity models in mice were utilized. Hepatic functional tests from serum collected at T24 and hepatic glutathione and superoxide dismutases from liver homogenates were evaluated. Histopathology analysis and merit of blending 3 standardized extracts were also confirmed. Statistically significant and dose-correlated inhibitions in serum ALT ranging from 52.5% (p = 0.004) to 34.6% (p = 0.05) in the APAP and 46.3% (p < 0.001) to 29.9% (p = 0.02) in the CCl4 models were observed for SAL administered at doses of 400–250 mg/kg. Moreover, SAL resulted in up to 60.6% and 80.2% reductions in serums AST and bile acid, respectively. The composition replenished depleted hepatic glutathione in association with an increase of hepatic superoxide dismutase. Unexpected synergistic protection from liver damage was also observed. Therefore, the composition SAL could be potentially utilized as an effective hepatic-detoxification agent for the protection from liver damage. PMID:27066270

  15. The Application of Simulation-Assisted Learning Statistics (SALS) for Correcting Misconceptions and Improving Understanding of Correlation

    ERIC Educational Resources Information Center

    Liu, T.-C.; Lin, Y.-C.; Kinshuk

    2010-01-01

    Simulation-based computer assisted learning (CAL) is recommended to help students understand important statistical concepts, although the current systems are still far from ideal. Simulation-Assisted Learning Statistics (SALS) is a simulation-based CAL that is developed with a learning model that is based on cognitive conflict theory to correct…

  16. Impact of LbSapSal Vaccine in Canine Immunological and Parasitological Features before and after Leishmania chagasi-Challenge.

    PubMed

    Resende, Lucilene Aparecida; Aguiar-Soares, Rodrigo Dian de Oliveira; Gama-Ker, Henrique; Roatt, Bruno Mendes; Mendonça, Ludmila Zanandreis de; Alves, Marina Luiza Rodrigues; Silveira-Lemos, Denise da; Corrêa-Oliveira, Rodrigo; Martins-Filho, Olindo Assis; Araújo, Márcio Sobreira Silva; Fujiwara, Ricardo Toshio; Gontijo, Nelder Figueiredo; Reis, Alexandre Barbosa; Giunchetti, Rodolfo Cordeiro

    2016-01-01

    Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum). A vaccine against canine visceral leishmaniasis (CVL) would be an important tool for decreasing the anxiety related to possible L. chagasi infection and for controlling human visceral leishmaniasis (VL). Because the sand fly salivary proteins are potent immunogens obligatorily co-deposited during transmission of Leishmania parasites, their inclusion in an anti-Leishmania vaccine has been investigated in past decades. We investigated the immunogenicity of the "LbSapSal" vaccine (L. braziliensis antigens, saponin as adjuvant, and Lutzomyia longipalpis salivary gland extract) in dogs at baseline (T0), during the post-vaccination protocol (T3rd) and after early (T90) and late (T885) times following L. chagasi-challenge. Our major data indicated that immunization with "LbSapSal" is able to induce biomarkers characterized by enhanced amounts of type I (tumor necrosis factor [TNF]-α, interleukin [IL]-12, interferon [IFN]-γ) cytokines and reduction in type II cytokines (IL-4 and TGF-β), even after experimental challenge. The establishment of a prominent pro-inflammatory immune response after "LbSapSal" immunization supported the increased levels of nitric oxide production, favoring a reduction in spleen parasitism (78.9%) and indicating long-lasting protection against L. chagasi infection. In conclusion, these results confirmed the hypothesis that the "LbSapSal" vaccination is a potential tool to control the Leishmania chagasi infection.

  17. Long-term effects of multiply pulsed dielectric barrier discharges in air on thin water layers over tissue: stationary and random streamers

    NASA Astrophysics Data System (ADS)

    Tian, Wei; Kushner, Mark J.

    2015-12-01

    Tissue covered by thin liquid layers treated by atmospheric pressure plasmas for biomedical applications ultimately requires a reproducible protocol for human healthcare. The desired outcomes of wet tissue treatment by dielectric barrier discharges (DBDs) depend on the plasma dose which determines the integral fluence of radicals, ions, electric fields and UV/VUV photons incident onto the tissue. These fluences are controlled by power, frequency and treatment time. To first order, these parameters determine the energy deposition (J cm-2) onto the tissue. However, energy deposition may not be the only parameter that determines the fluences of reactants to the underlying tissue. In this paper, we report on a computational investigation of multipulse DBDs interacting with wet tissue. The DBDs were simulated for 100 pulses at different repetition rates and liquid thicknesses followed by 10 s or more of afterglow. Two schemes were investigated—stationary and random. In the stationary scheme, the DBD plasma streamer continues to strike at the same location on the liquid layer, whereas in the random scheme the plasma streamer strikes at random locations on the liquid layer. These differences in streamer locations strongly affect the spatial distribution of solvated species such as OHaq and H2O2aq (‘aq’ represents an aqueous species), which have high rates of solvation. The spatial distribution of species such as NOaq, which have low rates of solvation, are less affected by the location of the streamer due to the remediating effects of diffusion in the air. The end result is that fluences to the tissue are sensitive to the spatial location of the streamer due to the ensuing reactions in the liquid between species that have low and high rates of solvation. These reactions can be controlled not only through location of the streamer, but also by repetition rate and thickness of the liquid layer.

  18. A Survey of Scattering, Attenuation, and Size Spectra Studies of Bubble Layers and Plumes Beneath the Air-Sea Interface.

    DTIC Science & Technology

    1991-08-30

    density. Raytraces were done from the layer source to the hydrophone at 267-m bottom depth and, finding refraction negligible out to 6-km radius, a... Radar ," in Wave Dynamics and Radio Probing of the Ocean Surface, Plenum, New York (1986). 56 [83] L. Kinsler and A. Frey, Fundamentals of Acoustics...Breaking in the Presence of Wind Drift and Swell," J. Fluid Mech. 66, 625-640 (1974). [1451 O.M. Phillips, " Radar Returns from the Sea Surface - Bragg

  19. Bidirectional air-sea exchange and accumulation of POPs (PAHs, PCBs, OCPs and PBDEs) in the nocturnal marine boundary layer

    NASA Astrophysics Data System (ADS)

    Lammel, Gerhard; Meixner, Franz X.; Vrana, Branislav; Efstathiou, Christos I.; Kohoutek, Jiři; Kukučka, Petr; Mulder, Marie D.; Přibylová, Petra; Prokeš, Roman; Rusina, Tatsiana P.; Song, Guo-Zheng; Tsapakis, Manolis

    2016-05-01

    As a consequence of long-range transported pollution, air-sea exchange can become a major source of persistent organic pollutants in remote marine environments. The vertical gradients in the air were quantified for 14 species, i.e. four parent polycyclic aromatic hydrocarbons (PAHs), three polychlorinated biphenyls (PCBs), three organochlorine pesticides (OCPs) and two polybrominated diphenylethers (PBDEs) in the gas-phase at a remote coastal site in the southern Aegean Sea in summer. Most vertical gradients were positive (Δc/Δz > 0), indicating downward (net depositional) flux. Significant upward (net volatilisational) fluxes were found for three PAHs, mostly during daytime, and for two OCPs, mostly during night-time, as well as for one PCB and one PBDE during part of the measurements. While phenanthrene was deposited, fluoranthene (FLT) and pyrene (PYR) seem to undergo flux oscillation, hereby not following a day-night cycle. Box modelling confirms that volatilisation from the sea surface has significantly contributed to the night-time maxima of OCPs. Fluxes were quantified based on eddy covariance. Deposition fluxes ranged from -28.5 to +1.8 µg m-2 day-1 for PAHs and -3.4 to +0.9 µg m-2 day-1 for halogenated compounds. Dry particle deposition of FLT and PYR did not contribute significantly to the vertical flux.

  20. Effects of Surface Heat Flux Anomalies on Stratification, Convective Growth and Vertical Transport within the Saharan Boundary Layer

    NASA Astrophysics Data System (ADS)

    Huang, Qian; Marsham, John; Parker, Doug; Tian, Wenshou; Grams, Christian; Cuesta, Juan; Flamant, Cyrille

    2010-05-01

    The very large surface sensible and very low latent heat fluxes in the Sahara desert lead to its unusually deep, almost dry-adiabatic boundary layer, that often reaches 6 km. This is often observed to consist of a shallow convective boundary layer (CBL) with a near neutral residual layer above (the Saharan Residual Layer, or SRL). It has been shown that the SRL can be both spatially extensive and persist throughout the day. Multiple near-neutral layers are frequently observed within the SRL, or within the SAL, each with a different water vapour and/or dust content, and each separated by a weak lid (e.g., Figure 1). A local maximum in not only relative humidity, but also water vapour mixing ratio (WVMR) is often seen at the top of the SRL or SAL. This structure suggests that in some locations, at some times, convection from the surface is mixing the full depth of the Saharan boundary layer, but in most locations and times this is not the case, and varying horizontal advection leads to the multiple layering observed. During the GERBILS (GERB Intercomparison of Longwave and Shortwave radiation) field campaign in the Sahara, coherent couplings were observed between surface albedo, CBL air temeperatures and CBL winds. Using two cases based on observations from GERBILS, large eddy model (LEM) simulations have been used to investigate the effects of surface flux anomalies on the growth of the summertime Saharan CBL into the Saharan Residual layer (SRL) above, and transport from the CBL into the SRL. Hot surface anomalies generated updraughts and convergence in the CBL that increased transport from the CBL into the SRL. The induced subsidence in regions away from the anomalies inhibited growth of the CBL there. If the domain-averaged surface fluxes were kept constant this led to a shallower, cooler CBL. If fluxes outside the anomalies were kept constant, so that stronger anomalies led to increased domain-averaged fluxes, this gave a warmer, shallower CBL. These effects

  1. Air-stable short-wave infrared PbS colloidal quantum dot photoconductors passivated with Al{sub 2}O{sub 3} atomic layer deposition

    SciTech Connect

    Hu, Chen; Gassenq, Alban; Chen, Hongtao; Roelkens, Günther; Justo, Yolanda; Hens, Zeger; Devloo-Casier, Kilian; Detavernier, Christophe

    2014-10-27

    A PbS colloidal quantum dot photoconductor with Al{sub 2}O{sub 3} atomic layer deposition (ALD) passivation for air-stable operation is presented. Two different types of inorganic ligands for the quantum dots, S{sup 2−} and OH{sup −}, are investigated. PbS/S{sup 2−} photoconductors with a cut-off wavelength up to 2.4 μm are obtained, and a responsivity up to 50 A/W at 1550 nm is reported. The corresponding specific detectivity is ∼3.4 × 10{sup 8} Jones at 230 K. The 3-dB bandwidth of the PbS/S{sup 2−} and PbS/OH{sup −} photodetectors is 40 Hz and 11 Hz, respectively.

  2. Quantitative Interpretation of Air Radon Progeny Fluctuations in Terms of Stability Conditions in the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Salzano, Roberto; Pasini, Antonello; Casasanta, Giampietro; Cacciani, Marco; Perrino, Cinzia

    2016-09-01

    Determining the mixing height using a tracer can improve the information obtained using traditional techniques. Here we provide an improved box model based on radon progeny measurements, which considers the vertical entrainment of residual layers and the variability in the soil radon exhalation rate. The potential issues in using progeny instead of radon have been solved from both a theoretical and experimental perspective; furthermore, the instrumental efficiency and the counting scheme have been included in the model. The applicability range of the box model has been defined by comparing radon-derived estimates with sodar and lidar data. Three intervals have been analyzed ("near-stable", "transition" and "turbulent"), and different processes have been characterized. We describe a preliminary application case performed in Rome, Italy, while case studies will be required to determine the range limits that can be applied in any circumstances.

  3. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    NASA Astrophysics Data System (ADS)

    Chen, Qi; Yan, Limin; Zhang, Hao; Li, Guoxiu

    2016-05-01

    Electrical characteristics of a nozzle-attached meso-scale premixed methane-air flame under low-frequency AC (0-4300 V, 0-500 Hz) and DC (0-3300 V) electric fields were studied. I-V curves were measured under different experimental conditions to estimate the magnitude of the total current 100-102 μA, the electron density 1015-1016 m-3 and further the power dissipation ≤ 0.7 W in the reaction zone. At the same time, the meso-scale premixed flame conductivity 10-4-10-3 Ω-1·m-1 as a function of voltage and frequency was experimentally obtained and was believed to represent a useful order-of magnitude estimate. Moreover, the influence of the collision sheath relating to Debye length (31-98 μm) and the contamination layer of an active electrode on measurements was discussed, based on the combination of simulation and theoretical analysis. As a result, the electrode sheath dimension was evaluated to less than 0.5 mm, which indicated a complex effect of the collision sheath on the current measurements. The surface contamination effect of an active electrode was further analyzed using the SEM imaging method, which showed elements immigration during the contamination layer formation process. supported by National Natural Science Foundation of China (No. 51376021), and the Fundamental Research Fund for Major Universities (No. 2013JBM079)

  4. Positive impact of the new 5-layer soil-hydrology scheme on seasonal prediction skill of 2-meter air temperatures over Europe

    NASA Astrophysics Data System (ADS)

    Bunzel, Felix; Müller, Wolfgang; Stacke, Tobias; Hagemann, Stefan; Dobrynin, Mikhail; Baehr, Johanna; Fröhlich, Kristina

    2016-04-01

    Recent studies show that the initialization of soil moisture has the potential to improve the skill of seasonal predictions with coupled climate models. Particularly, soil-moisture memory in the root zone is found to affect the predictability of surface state variables. However, in order to simulate the connection between root-zone soil-moisture and the near-surface atmospheric state realistically, the soil-hydrology scheme implemented in a coupled climate model requires a certain level of complexity. In this study, we first compare the quality of soil-moisture simulation in full-field assimilation experiments performed with the Max Planck Institute Earth System Model (MPI-ESM) in two different setups, one using the old bucket-type soil scheme and one using the new 5-layer soil-hydrology scheme. We find soil moisture to be more realistically simulated when MPI-ESM is used with the new 5-layer soil scheme. In a second step, from each of the two assimilation experiments a set of seasonal hindcast simulations is started. Each hindcast set consists of 10-member ensembles initialized on 1 May and 1 November each year within 1981-2012 with a hindcast length of 6 months each. We find the new 5-layer soil-hydrology scheme to improve the hindcast skill of both summer and winter 2-meter air temperatures over Europe compared to the old bucket-type soil scheme. In order to find possible sources for the improvement, land-atmosphere coupling is analyzed in the two hindcast sets, and a potential link to the atmospheric blocking frequency is investigated.

  5. One-dimensional analytical model for oxide thin film growth on Ti metal layers during laser heating in air

    NASA Astrophysics Data System (ADS)

    Jiménez Pérez, J. L.; Sakanaka, P. H.; Algatti, M. A.; Mendoza-Alvarez, J. G.; Cruz Orea, A.

    2001-05-01

    This paper presents the theoretical and experimental results for oxide thin film growth on titanium films previously deposited over glass substrate. Ti films of thickness 0.1 μm were heated by Nd:YAG laser pulses in air. The oxide tracks were created by moving the samples with a constant speed of 2 mm/s, under the laser action. The micro-topographic analysis of the tracks was performed by a microprofiler. The results taken along a straight line perpendicular to the track axis revealed a Gaussian profile that closely matches the laser's spatial mode profile, indicating the effectiveness of the surface temperature gradient on the film's growth process. The sample's micro-Raman spectra showed two strong bands at 447 and 612 cm -1 associated with the TiO 2 structure. This is a strong indication that thermo-oxidation reactions took place at the Ti film surface that reached an estimated temperature of 1160 K just due to the action of the first pulse. The results obtained from the numerical integration of the analytical equation which describes the oxidation rate (Wagner equation) are in agreement with the experimental data for film thickness in the high laser intensity region. This shows the partial accuracy of the one-dimensional model adopted for describing the film growth rate.

  6. The study of the effect of the surface wave on turbulent stably-stratified boundary layer air-flow by direct numerical simulation

    NASA Astrophysics Data System (ADS)

    Druzhinin, Oleg; Troitskaya, Yliya; Zilitinkevich, Sergej

    2015-04-01

    Detailed knowledge of the interaction of surface water waves with the wind flow is of primary importance for correct parameterization of turbulent momentum and heat fluxes which define the energy and momentum transfer between the atmosphere and hydrosphere. The objective of the present study is to investigate the properties of the stably stratified turbulent boundary-layer (BL) air-flow over waved water surface by direct numerical simulation (DNS) at a bulk Reynolds number varying from 15000 to 80000 and the surface-wave slope up to ka = 0.2. The DNS results show that the BL-flow remains in the statistically stationary, turbulent regime if the Reynolds number (ReL) based on the Obukhov length scale and friction velocity is sufficiently large (ReL > 100). In this case, mean velocity and temperature vertical profiles are well predicted by log-linear asymptotic solutions following from the Monin-Obukhov similarity theory provided the velocity and temperature roughness parameters, z0U and z0T, are appropriately prescribed. Both z0U and z0T increase for larger surface-wave slope. DNS results also show that turbulent momentum and heat fluxes and turbulent velocity and temperature fluctuations are increased for larger wave slope (ka) whereas the mean velocity and temperature derivatives remain practically the same for different ka. Thus, we conclude that the source of turbulence enhancement in BL-flow are perturbations induced by the surface wave, and not the shear instability of the bulk flow. On the other hand, if stratification is sufficiently strong, and the surface-wave slope is sufficiently small, the BL-flow over waved surface relaminarizes in the bulk of the domain. However, if the surface-wave slope exceeds a threshold value, the velocity and temperature fluctuations remain finite in the vicinity of the critical-layer level, where the surface-wave phase velocity coincides with the mean flow velocity. We call this new stably-stratified BL-flow regime observed in

  7. RNAPro•SAL: a device for rapid and standardized collection of saliva RNA and proteins.

    PubMed

    Chiang, Samantha H; Thomas, Gerald A; Liao, Wei; Grogan, Tristan; Buck, Robert L; Fuentes, Laurel; Yakob, Maha; Laughlin, Mary J; Schafer, Chris; Nazmul-Hossain, Abu; Wei, Fang; Elashoff, David; Slowey, Paul D; Wong, David T W

    2015-02-01

    The stabilization and processing of salivary transcriptome and proteome biomarkers is a critical challenge due to the ubiquitous nature of nucleases and proteases as well as the inherent instability of these biomarkers. Furthermore, extension of salivary transcriptome and proteome analysis to point-of-care and remote sites requires the availability of self-administered ambient temperature collection and storage tools. To address these challenges, a self-contained whole saliva collection and extraction system, RNAPro•SAL, has been developed that provides rapid ambient temperature collection along with concurrent processing and stabilization of extracellular RNA (exRNA) and proteins. The system was compared to the University of California, Los Angeles (UCLA) standard clinical collection process (standard operating procedure, SOP). Both systems measured total RNA and protein, and exRNA IL-8, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), β-actin and ribosomal protein S9 (RPS9) by qPCR. Proteome analysis was measured by EIA analysis of interleukin-8 (IL-8), and β-actin, as well as total protein. Over 97% of viable cells were removed by both methods. The system compared favorably to the labor-intensive clinical SOP, which requires low-temperature collection and isolation, yielding samples with similar protein and exRNA recovery and stability.

  8. Heavy metal contents of paddy fields of Alcácer do Sal, Portugal.

    PubMed

    Fernandes, J C; Henriques, F S

    1990-01-01

    Recent claims of metal contamination in the lower reaches of the Sado River, in the Alcácer do Sal region, Portugal, a major rice-producing area were investigated by carrying out metal surveys in the area. The elements Fe, Mn, Zn, Cu and Pb were measured in the soil and in rice plant parts--roots, shoots and grain--as well as in some weeds growing in the Sado banks, near the paddy fields. Results showed that the metal contents of paddy soils were similar to background concentrations, with the exception of Zn and Cu, which were above those concentrations and reached their highest levels at Vale de Guizo, the monitored station located furthest upstream in the Sado River. At some sites, plant roots accumulated relatively large amounts of Fe, Mn, Zn and Cu, but the shoot levels of these metals were within the normal range for rice plants. It is possible that varying, but significant, amounts of Fe associated with the roots were in the form of ferric hydroxide plaque covering their surfaces. Copper levels in the shoots of rice were below the normal contents cited for this plant in the literature. Metal levels of river sediments collected near Vale de Guizo seem to corroborate the possibility of some metal contamination in the Sado River, most probably derived from pyrites mining activity in the upper zone of the Sado basin.

  9. RNAPro•SAL: A device for rapid and standardized collection of saliva RNA and proteins

    PubMed Central

    Chiang, Samantha H.; Thomas, Gerald A.; Liao, Wei; Grogan, Tristan; Buck, Robert L.; Fuentes, Laurel; Yakob, Maha; Laughlin, Mary J.; Schafer, Chris; Nazmul-Hossain, Abu; Wei, Fang; Elashoff, David; Slowey, Paul D.; Wong, David T.W.

    2015-01-01

    The stabilization and processing of salivary transcriptome and proteome biomarkers is a critical challenge due to the ubiquitous nature of nucleases and proteases as well as the inherent instability of these biomarkers. Furthermore, extension of salivary transcriptome and proteome analysis to point-of-care and remote sites requires the availability of self-administered ambient temperature collection and storage tools. To address these challenges, a self-contained whole saliva collection and extraction system, RNAPro•SAL, has been developed that provides rapid ambient temperature collection along with concurrent processing and stabilization of extracellular RNA (exRNA) and proteins. The system was compared to the University of California, Los Angeles (UCLA) standard clinical collection process (standard operating procedure, SOP). Both systems measured total RNA and protein, and exRNA IL-8, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), β-actin and ribosomal protein S9 (RPS9) by qPCR. Proteome analysis was measured by EIA analysis of interleukin-8 (IL-8), and β-actin, as well as total protein. Over 97% of viable cells were removed by both methods. The system compared favorably to the labor-intensive clinical SOP, which requires low-temperature collection and isolation, yielding samples with similar protein and exRNA recovery and stability. PMID:25652029

  10. The consequences of air flow on the distribution of aqueous species during dielectric barrier discharge treatment of thin water layers

    NASA Astrophysics Data System (ADS)

    Tian, Wei; Lietz, Amanda M.; Kushner, Mark J.

    2016-10-01

    The desired outcomes of wet tissue treatment by dielectric barrier discharges (DBDs) strongly depend on the integrated fluences of reactive species incident onto the tissue, which are determined by power, frequency and treatment time. The reactivity produced by such plasmas is often expected to be proportional to treatment time due to the accumulation of radicals in the liquid over the tissue. However, one of the typically uncontrolled parameters in DBD treatment of liquids and tissue is gas flow, which could affect the delivery of plasma produced radicals to the tissue. Gas flow can redistribute long-lived, plasma produced gas phase species prior to solvating in the liquid, while not greatly affecting the solvation of short-lived species. Gas flow can therefore potentially be a control mechanism for tailoring the fluences of reactive species to the tissue. In this paper, we report on a computational investigation of the consequences of gas flow on treatment of liquid layers covering tissue by atmospheric DBDs by up to 100 pulses. We found that gas flow (through residence time of the gas) can control the production of gas phase species requiring many collisions to form, such as reactive nitrogen species (RNS). The resulting solvation of the RNS in turn controls the production of aqueous species such as \\text{NO}\\text{3aq}- and \\text{ONOO}\\text{aq}- (aq denotes an aqueous species). With the exception of O3 and O3aq, reactive oxygen species (ROS) are less sensitive to gas flow, and so OHaq and H2O2aq, are determined primarily by discharge properties.

  11. Study of enhanced red emission from Sm(Sal) 3Phen ternary complexes in Poly Vinyl Alcohol film

    NASA Astrophysics Data System (ADS)

    Kaur, Gagandeep; Dwivedi, Y.; Rai, S. B.

    2010-09-01

    In the present work, dinuclear complexes of salicylic acid (Sal) and 1,10-phenanthroline (Phen) were synthesized with different concentrations of Samarium ion (Sm 3+) in Poly Vinyl Alcohol (PVA) polymer films and their structural and spectroscopic properties were investigated. Judd-Ofelt theory has been employed to estimate the several radiative parameters for SmCl 3 and Sm(Sal) 3Phen complex in PVA polymer film which are in fairly agreement between the experimental and the theoretical values supporting the J-O theory. Photoluminescence properties of the complex have been studied on 355 nm and 400 nm excitations in steady state as well as in time domain. On the basis of the UV-Vis absorption, FT-IR absorption, excitation, emission spectra and decay curves, spectroscopic properties of these films were studied and the photophysics involved was explained in terms of energy transfer and the RE encapsulation effect.

  12. Novel acyloxy derivatives of branched mono- and polyol esters of sal fat: multiviscosity grade lubricant base stocks.

    PubMed

    Kamalakar, Kotte; Sai Manoj, Gorantla N V T; Prasad, Rachapudi B N; Karuna, Mallampalli S L

    2014-12-10

    Sal fat, a nontraditional seed oil, was chemically modified to obtain base stocks with a wide range of specifications that can replace mineral oil base stocks. Sal fatty acids were enriched to 72.6% unsaturation using urea adduct method and reacted with branched mono alcohol, 2-ethylhexanol (2-EtH), and polyols namely neopentyl glycol (NPG) and trimethylolpropane (TMP) to obtain corresponding esters. The esters were hydroxylated and then acylated using propionic, butyric, and hexanoic anhydrides to obtain corresponding acylated derivatives. The acylated TMP esters exhibited very high viscosities (427.35-471.93 cSt at 40 °C) similar to those of BS 150 mineral oil base stock range, ISO VG 460, while the acylated NPG esters (268.81-318.84 cSt at 40 °C) and 2-EtH esters viscosities (20.94-24.44 cSt at 40 °C) exhibited viscosities in the range of ISO VG 320 and 22 respectively with good viscosity indices. Acylated NPG esters were found suitable for high temperature and acylated 2-ethylhexyl esters for low viscosity grade industrial applications. It was observed that the thermo-oxidative stabilities of all acylated products were found better compared to other vegetable oil based base stocks. Overall, all the sal fat based lubricant base stocks are promising candidates with a wide range of properties, which can replace most of the mineral oil base stocks with appropriate formulations.

  13. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides.

    PubMed

    Mali, Sawanta S; Hong, Chang Kook

    2016-05-19

    There has been fast recent progress in perovskite solar cells (PSCs) towards low cost photovoltaic technology. Organometal mixed halide (MAPbX or FAPbX) perovskites are the most promising light absorbing material sandwiched between the electron transport layer (ETL) and hole transport layer (HTL). These two layers play a critical role in boosting the power conversion efficiency (PCE) and maintaining air stability. However, the device stability is a serious issue in regular as well as p-i-n inverted type perovskite solar cells. This mini-review briefly outlines the state-of-art of p-i-n/n-i-p type planar hybrid perovskite solar cells using MAPbX/FAPbX perovskite absorbing layers. Later, we will focus on recent trends, progress and further opportunities in exploring the air stable hybrid planar structure PSCs.

  14. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides

    NASA Astrophysics Data System (ADS)

    Mali, Sawanta S.; Hong, Chang Kook

    2016-05-01

    There has been fast recent progress in perovskite solar cells (PSCs) towards low cost photovoltaic technology. Organometal mixed halide (MAPbX or FAPbX) perovskites are the most promising light absorbing material sandwiched between the electron transport layer (ETL) and hole transport layer (HTL). These two layers play a critical role in boosting the power conversion efficiency (PCE) and maintaining air stability. However, the device stability is a serious issue in regular as well as p-i-n inverted type perovskite solar cells. This mini-review briefly outlines the state-of-art of p-i-n/n-i-p type planar hybrid perovskite solar cells using MAPbX/FAPbX perovskite absorbing layers. Later, we will focus on recent trends, progress and further opportunities in exploring the air stable hybrid planar structure PSCs.

  15. Seasonal variation of local atmospheric circulations and boundary layer structure in the Beijing-Tianjin-Hebei region and implications for air quality

    NASA Astrophysics Data System (ADS)

    Miao, Yucong; Hu, Xiao-Ming; Liu, Shuhua; Qian, Tingting; Xue, Ming; Zheng, Yijia; Wang, Shu

    2015-12-01

    The Beijing-Tianjin-Hebei (BTH) region experiences frequent heavy haze pollution in fall and winter. Pollution was often exacerbated by unfavorable atmospheric boundary layer (BL) conditions. The topography in this region impacts the BL processes in complex ways. Such impacts and implications on air quality are not yet clearly understood. The BL processes in all four seasons in BTH are thus investigated in this study using idealized simulations with the WRF-Chem model. Results suggest that seasonal variation of thermal conditions and synoptic patterns significantly modulates BL processes. In fall, with a relatively weak northwesterly synoptic forcing, thermal contrast between the mountains and the plain leads to a prominent mountain-plain breeze circulation (MPC). In the afternoon, the downward branch of the MPC, in addition to northwesterly warm advection, suppresses BL development over the western side of BTH. In the eastern coastal area, a sea-breeze circulation develops late in the morning and intensifies during the afternoon. In summer, southeasterly BL winds allow the see-breeze front to penetrate farther inland (˜150 km from the coast), and the MPC is less prominent. In spring and winter, with strong northwesterly synoptic winds, the sea-breeze circulation is confined in the coastal area, and the MPC is suppressed. The BL height is low in winter due to strong near-surface stability, while BL heights are large in spring due to strong mechanical forcing. The relatively low BL height in fall and winter may have exacerbated the air pollution, thus contributing to the frequent severe haze events in the BTH region.

  16. Geo-diversity and geo-materials in the region of Rabat-Salé-Zemmour-Zaer: Characterization and Rationalization of Utilization

    NASA Astrophysics Data System (ADS)

    Belhaj, Siham; Bahi, Lahcen; Akhssas, Ahmed

    2016-04-01

    The Rabat-Salé-Zemmour-Zaer (RSZZ) is distinguished by a rich geology is varied. Outcrops are found in both the Paleozoic basement, especially along the major wadis in the area and a fairly extensive coverage postpaléozoïque and locally very thick. It offers a wide variety of petrographic facies some of which the construction of geomaterials value (GMC), very solicited by the construction sector and public works (BTP). Among the most important GMC furniture and beds of RSZZ: - The sands. They are a fundamental component for the preparation of mortar and hydraulic concrete. They also enter into the composition of adobe and are used for the foundation of shoes. -The Clays. They are mainly used by ceramists (industrial units manufacturing tiles). The red clay of Triassic age are most represented in the Region in deposits whose thickness can reach several tens of meters. -The Calcarenite. : It is the most used local stone in building the cities of Rabat and Salé, where she is well known as the Stone of Salé. The same stone is used in the manufacture of lime through calcination. Geologically, it is a calcareous sandstone, of Pliocene-Quaternary age that is in the form of a dune system that runs parallel to the Atlantic coast. -The Limestones: These massive limestones and more or less metamorphosed dolomitized Devonian. These limestone outcrop along major wadis of the region (Akrech, Ykem, ...) as layers sometimes quite thick and more or less tectonized. According to localities, these limestones show a wide range of colors (white, gray, black pink) and a wide variety of structures (colorful, beaded, veined, textured) - The quartzites. They correspond to Ordovician bars that appear quite often emerged in relation to other surrounding formations because of their high resistance to erosion. The rock is generally brownish gray and shows a very high hardness related to its siliceous. Local and temporary holdings allow blocks extraction for various public works

  17. Pharmacology and anti-addiction effects of the novel κ opioid receptor agonist Mesyl Sal B, a potent and long-acting analogue of salvinorin A

    PubMed Central

    Simonson, B; Morani, A S; Ewald, A W M; Walker, L; Kumar, N; Simpson, D; Miller, J H; Prisinzano, T E; Kivell, B M

    2015-01-01

    BACKGROUND AND PURPOSE Acute activation of κ opioid (KOP) receptors results in anticocaine-like effects, but adverse effects, such as dysphoria, aversion, sedation and depression, limit their clinical development. Salvinorin A, isolated from the plant Salvia divinorum, and its semi-synthetic analogues have been shown to have potent KOP receptor agonist activity and may induce a unique response with similar anticocaine addiction effects as the classic KOP receptor agonists, but with a different side effect profile. EXPERIMENTAL APPROACH We evaluated the duration of effects of Mesyl Sal B in vivo utilizing antinociception assays and screened for cocaine-prime induced cocaine-seeking behaviour in self-administering rats to predict anti-addiction effects. Cellular transporter uptake assays and in vitro voltammetry were used to assess modulation of dopamine transporter (DAT) function and to investigate transporter trafficking and kinase signalling pathways modulated by KOP receptor agonists. KEY RESULTS Mesyl Sal B had a longer duration of action than SalA, had anti-addiction properties and increased DAT function in vitro in a KOP receptor-dependent and Pertussis toxin-sensitive manner. These effects on DAT function required ERK1/2 activation. We identified differences between Mesyl Sal B and SalA, with Mesyl Sal B increasing the Vmax of dopamine uptake without altering cell-surface expression of DAT. CONCLUSIONS AND IMPLICATIONS SalA analogues, such as Mesyl Sal B, have potential for development as anticocaine agents. Further tests are warranted to elucidate the mechanisms by which the novel salvinorin-based neoclerodane diterpene KOP receptor ligands produce both anti-addiction and adverse side effects. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2 PMID:24641310

  18. Reorientation of the ‘free OH’ group in the top-most layer of air/water interface of sodium fluoride aqueous solution probed with sum-frequency generation vibrational spectroscopy

    SciTech Connect

    Feng, Ran-Ran; Guo, Yuan; Wang, Hongfei

    2014-09-17

    Many experimental and theoretical studies have established the specific anion, as well as cation effects on the hydrogen-bond structures at the air/water interface of electrolyte solutions. However, the ion effects on the top-most layer of the air/water interface, which is signified by the non-hydrogen-bonded so-called ‘free O-H’ group, has not been discussed or studied. In this report, we present the measurement of changes of the orientational angle of the ‘free O-H’ group at the air/water interface of the sodium fluoride (NaF) solutions at different concentrations using the interface selective sum-frequency generation vibrational spectroscopy (SFG-VS) in the ssp and ppp polarizations. The polarization dependent SFG-VS results show that the average tilt angle of the ‘free O-H’ changes from about 35.3 degrees ± 0.5 degrees to 43.4 degrees ± 2.1degrees as the NaF concentration increase from 0 to 0.94M (nearly saturated). Such tilt angle change is around the axis of the other O-H group of the same water molecule at the top-most layer at the air/water interface that is hydrogen-bonded to the water molecules below the top-most layer. These results provide quantitative molecular details of the ion effects of the NaF salt on the structure of the water molecules at the top-most layer of the air/water interfacial, even though both the Na+ cation and the F- anion are believed to be among the most excluded ions from the air/water interface.

  19. Marine geophysical data—Point Sal to Refugio State Beach, southern California

    USGS Publications Warehouse

    Johnson, Samuel Y.; Hartwell, Stephen; Beeson, Jeffrey

    2016-01-01

    This data release includes approximately 1,032 km of marine single-channel seismic-reflection data collected by the U.S. Geological Survey on a research cruise (USGS survey 2014-632-FA) in July and August, 2014, between Point Sal and Refugio State Beach. The dataset includes 168 profiles, most of which were collected on tracklines roughly perpendicular to the coast at 1 km line spacing; additional profiles were collected on coast-parallel tie lines. These data were acquired to support the California Seafloor Mapping Program and USGS Geologic Hazards projects.Seismic-reflection data were collected using a minisparker system that creates an acoustic signal by discharging an electrical pulse between electrodes and a ground that generates a frequency spectrum roughly between 200 and 1,600 Hz. At boat speeds of 4 to 4.5 nm/hour, seismic traces were collected roughly every 1 to 2 meters. Water depths were generally between 50 m and 150 m, but as shallow as 10 meters near the shoreline, and as deep as 480 m for profiles crossing the Santa Barbara basin. Acoustic pulses were generated at 0.5-second intervals on most profiles; a 1-second interval was used on the few profiles collected in deeper water. Standard SEG-Y files were generated using a Triton Subbottom Logger (SBL). Seismic data processing was accomplished using Sioseis, a public-domain software developed at Scripps Institute of Oceanography (part of the University of California at San Diego). The processing of these data consisted of a bandpass filter, mute function, automatic gain control, water bottom detect, swell correction, and scaling/plotting. Both raw data in SEG-Y format and processed data (“Corrected SEG-Y”) are provided in this data release. 

  20. Numerical simulation of VAWT stochastic aerodynamic loads produced by atmospheric turbauence: VAWT-SAL code

    SciTech Connect

    Homicz, G.F.

    1991-09-01

    Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). A principal source of blade fatigue is thought to be the stochastic (i.e., random) aerodynamic loads created by atmospheric turbulence. This report describes the theoretical background of the VAWT Stochastic Aerodynamic Loads (VAWT-SAL) computer code, whose purpose is to numerically simulate these random loads, given the rotor geometry, operating conditions, and assumed turbulence properties. A Double-Multiple-Stream Tube (DMST) analysis is employed to model the rotor's aerodynamic response. The analysis includes the effects of Reynolds number variations, different airfoil sections and chord lengths along the blade span, and an empirical model for dynamic stall effects. The mean ambient wind is assumed to have a shear profile which is described by either a power law or a logarithmic variation with height above ground. Superimposed on this is a full 3-D field of turbulence: i.e., in addition to random fluctuations in time, the turbulence is allowed to vary randomly in planes perpendicular to the mean wind. The influence of flow retardation on the convection of turbulence through the turbine is also modeled. Calculations are presented for the VAWT 34-m Test Bed currently in operation at Bushland, Texas. Predicted time histories of the loads, as well as their Fourier spectra, are presented and discussed. Particular emphasis is placed on the differences between so-called steady-state'' (mean wind only) predictions, and those produced with turbulence present. Somewhat surprisingly, turbulence is found to be capable of either increasing or decreasing the average output power, depending on the turbine's tip-speed ratio. A heuristic explanation for such behavior is postulated, and a simple formula is derived for predicting the magnitude of this effect without the need for a full stochastic simulation. 41 refs., 32 figs., 1 tab.

  1. A mutant allele of the SUP45 (SAL4) gene of Saccharomyces cerevisiae shows temperature-dependent allosuppressor and omnipotent suppressor phenotypes.

    PubMed

    Stansfield, I; Akhmaloka; Tuite, M F

    1995-04-01

    Using a plasmid-based termination-read-through assay, the sal4-2 conditional-lethal (temperature-sensitive) allele of the SUP45 (SAL4) gene was shown to enhance the efficiency of the weak ochre suppressor tRNA SUQ5 some 10-fold at 30 degrees C. Additionally, this allele increased the suppressor efficiency of SRM2-2, a weak tRNA(Gln) ochre suppressor, indicating that the allosuppressor phenotype is not SUQ5-specific. A sup+ sal4-2 strain also showed a temperature-dependent omnipotent suppressor phenotype, enhancing readthrough of all three termination codons. Combining the sal4-2 allele with an efficient tRNA nonsense suppressor (SUP4) increased the temperature-sensitivity of that strain, indicating that enhanced nonsense suppressor levels contribute to the conditional-lethality conferred by the sal4-2 allele. However, UGA suppression levels in a sup+ sal4-2 strain following a shift to the non-permissive temperature reached a maximum significantly below that exhibited by a non-temperature sensitive SUP4 suppressor strain. Enhanced nonsense suppression may not therefore be the primary cause of the conditional-lethality of this allele. These data indicate a role for Sup45p in translation termination, and possibly in an additional, as yet unidentified, cellular process.

  2. The Response Regulator CroR Modulates Expression of the Secreted Stress-Induced SalB Protein in Enterococcus faecalis

    PubMed Central

    Muller, Cécile; Le Breton, Yoann; Morin, Thierry; Benachour, Abdellah; Auffray, Yanick; Rincé, Alain

    2006-01-01

    The Enterococcus faecalis two-component signal transduction system CroRS, also referred as the RR-HK05 pair, is required for intrinsic β-lactam resistance (Y. R. Comenge, R. Quintiliani, Jr., L. Li, L. Dubost, J. P. Brouard, J. E. Hugonnet, and M. Arthur, J. Bacteriol. 185:7184-7192, 2003) and is also suspected to be involved in the expression of salB (previously referred to as sagA), a gene important for resistance to environmental stress and cell morphology (Y. Le Breton, G. Boël, A. Benachour, H. Prévost, Y. Auffray, and A. Rincé, Environ. Microbiol. 5:329-337, 2003). In this report, we provide genetic and biochemical evidence that salB encodes a secreted protein that is expressed from a monocistronic stress-inducible operon. Consistent with CroR being a direct transcriptional activator of the salB expression, CroR was found to bind to the salB promoter region in electrophoretic mobility shift assays. Interestingly, we provide evidence that SalB does not play a role in the intrinsic β-lactam resistance associated with CroRS. We also show that the CroRS system is able to regulate its own expression. The sequence of the CroRS binding site in the salB and croR promoter regions was determined using DNase I footprinting assays. PMID:16547051

  3. Salvianolic Acid B (Sal B) Protects Retinal Pigment Epithelial Cells from Oxidative Stress-Induced Cell Death by Activating Glutaredoxin 1 (Grx1).

    PubMed

    Liu, Xiaobin; Xavier, Christy; Jann, Jamieson; Wu, Hongli

    2016-11-03

    Protein glutathionylation, defined as the formation of protein mixed disulfides (PSSG) between cysteine residues and glutathione (GSH), can lead to cell death. Glutaredoxin 1 (Grx1) is a thiol repair enzyme which catalyzes the reduction of PSSG. Therefore, Grx1 exerts strong anti-apoptotic effects by improving the redox state, especially in times of oxidative stress. However, there is currently no compound that is identified as a Grx1 activator. In this study, we identified and characterized Salvianolic acid B (Sal B), a natural compound, as a Grx1 inducer, which potently protected retinal pigment epithelial (RPE) cells from oxidative injury. Our results showed that treatment with Sal B protected primary human RPE cells from H₂O₂-induced cell damage. Interestingly, we found Sal B pretreatment upregulated Grx1 expression in RPE cells in a time- and dose-dependent manner. Furthermore, NF-E2-related factor 2 (Nrf2), the key transcription factor that regulates the expression of Grx1, was activated in Sal B treated RPE cells. Further investigation showed that knockdown of Grx1 by small interfering RNA (siRNA) significantly reduced the protective effects of Sal B. We conclude that Sal B protects RPE cells against H₂O₂-induced cell injury through Grx1 induction by activating Nrf2 pathway, thus preventing lethal accumulation of PSSG and reversing oxidative damage.

  4. Salvianolic Acid B (Sal B) Protects Retinal Pigment Epithelial Cells from Oxidative Stress-Induced Cell Death by Activating Glutaredoxin 1 (Grx1)

    PubMed Central

    Liu, Xiaobin; Xavier, Christy; Jann, Jamieson; Wu, Hongli

    2016-01-01

    Protein glutathionylation, defined as the formation of protein mixed disulfides (PSSG) between cysteine residues and glutathione (GSH), can lead to cell death. Glutaredoxin 1 (Grx1) is a thiol repair enzyme which catalyzes the reduction of PSSG. Therefore, Grx1 exerts strong anti-apoptotic effects by improving the redox state, especially in times of oxidative stress. However, there is currently no compound that is identified as a Grx1 activator. In this study, we identified and characterized Salvianolic acid B (Sal B), a natural compound, as a Grx1 inducer, which potently protected retinal pigment epithelial (RPE) cells from oxidative injury. Our results showed that treatment with Sal B protected primary human RPE cells from H2O2-induced cell damage. Interestingly, we found Sal B pretreatment upregulated Grx1 expression in RPE cells in a time- and dose-dependent manner. Furthermore, NF-E2-related factor 2 (Nrf2), the key transcription factor that regulates the expression of Grx1, was activated in Sal B treated RPE cells. Further investigation showed that knockdown of Grx1 by small interfering RNA (siRNA) significantly reduced the protective effects of Sal B. We conclude that Sal B protects RPE cells against H2O2-induced cell injury through Grx1 induction by activating Nrf2 pathway, thus preventing lethal accumulation of PSSG and reversing oxidative damage. PMID:27827892

  5. Effects of bulk colloidal stability on adsorption layers of poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate at the air-water interface studied by neutron reflectometry.

    PubMed

    Campbell, Richard A; Yanez Arteta, Marianna; Angus-Smyth, Anna; Nylander, Tommy; Varga, Imre

    2011-12-29

    We show for the oppositely charged system poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate that the cliff edge peak in its surface tension isotherm results from the comprehensive precipitation of bulk complexes into sediment, leaving a supernatant that is virtually transparent and a depleted adsorption layer at the air/water interface. The aggregation and settling processes take about 3 days to reach completion and occur at bulk compositions around charge neutrality of the complexes which lack long-term colloidal stability. We demonstrate excellent quantitative agreement between the measured surface tension values and a peak calculated from the surface excess of surfactant in the precipitation region measured by neutron reflectometry, using the approximation that there is no polymer left in the liquid phase. The nonequilibrium nature of the system is emphasized by the production of very different interfacial properties from equivalent aged samples that are handled differently. We go on to outline our perspective on the "true equilibrium" state of this intriguing system and conclude with a comment on its practical relevance given that the interfacial properties can be so readily influenced by the handling of kinetically trapped bulk aggregates.

  6. Enhancement in Photovoltaic Properties of Plasmonic Nanostructures Incorporated Organic Solar Cells Processed in Air Using P3HT:PCBM as a Model Active Layer

    NASA Astrophysics Data System (ADS)

    Aneesh, P. M.; Kumar, C. Ram; Reshmi Varma, P. C.; Vivek, K.; Namboothiry, Manoj A. G.

    2015-07-01

    The effect of incorporation of plasmonic gold (Au) nanoparticle at the interface between transparent front electrode and hole transporting layer of molybdenum trioxide is studied using bulk heterojunction organic photovoltaic cells (OPVs) of poly-3- hexylthiophene and phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) fabricated in ambient air condition as a model system. The current-voltage measurement of ITO/MoO3/P3HT:PC61BM/Al and Au incorporated OPVs under AM1.5G light of intensity 1 Sun showed 16% increase in short circuit current density (JSC) and a 25% improvement in power conversion efficiency (PCE) with the incorporation of Au nanoparticles. The external quantum efficiency (EQE) measurement showed values varying from 40% to 60% over a wavelength range 350 nm to 700 nm with EQE enhancement over a broad spectral window. Scanning electron microscope studies were used to study the morphology of the Au nanoparticles made.

  7. Engineering topological superconductors using surface atomic-layer/molecule hybrid materials

    NASA Astrophysics Data System (ADS)

    Uchihashi, Takashi

    2015-08-01

    Surface atomic-layer (SAL) superconductors consisting of epitaxially grown metal adatoms on a clean semiconductor surface have been recently established. Compared to conventional metal thin films, they have two important features: (i) space-inversion symmetry-breaking throughout the system and (ii) high sensitivity to surface adsorption of foreign species. These potentially lead to manifestation of the Rashba effect and a Zeeman field exerted by adsorbed magnetic organic molecules. After introduction of the archetypical SAL superconductor Si(111)-(√7 × √3)-In, we describe how these features are utilized to engineer a topological superconductor with Majorana fermions and discuss its promises and expected challenges.

  8. Cathodes for lithium-air battery cells with acid electrolytes

    SciTech Connect

    Xing, Yangchuan; Huang, Kan; Li, Yunfeng

    2016-07-19

    In various embodiments, the present disclosure provides a layered metal-air cathode for a metal-air battery. Generally, the layered metal-air cathode comprises an active catalyst layer, a transition layer bonded to the active catalyst layer, and a backing layer bonded to the transition layer such that the transition layer is disposed between the active catalyst layer and the backing layer.

  9. Behavior of cationic surfactants and short chain alcohols in mixed surface layers at water-air and polymer-water interfaces with regard to polymer wettability. I. Adsorption at water-air interface.

    PubMed

    Zdziennicka, Anna; Jańczuk, Bronisław

    2010-09-01

    concentration of cationic surfactant was assumed equal to Gibbs surface excess concentration. For determination of the composition of the surface layer, its proper thickness was assumed. The composition of the surface mixed monolayer was discussed with regard to the standard free energy of cationic surfactant and alcohol adsorption at water-air interface determined in different ways. The standard free energy of adsorption of "pure" cationic surfactants determined from the Langmuir and Aronson and Rosen equations was compared to that deduced on the basis of Cp(20), and the surface tension of the cationic surfactant tail and tail-water interface tension.

  10. Air oxidation of hydrazine. 1. Reaction kinetics on natural kaolinites, halloysites, and model substituent layers with varying iron and titanium oxide and O- center contents

    NASA Technical Reports Server (NTRS)

    Coyne, L.; Mariner, R.; Rice, A.

    1991-01-01

    Air oxidation of hydrazine was studied by using a group of kaolinites, halloysites, and substituent oxides as models for the tetrahedral and octahedral sheets. The rate was found to be linear with oxygen. The stoichiometry showed that oxygen was the primary oxidant and that dinitrogen was the only important nitrogen-containing product. The rates on kaolinites were strongly inhibited by water. Those on three-dimensional silica and gibbsite appeared not to be. That on a supposedly layered silica formed from a natural kaolinite by acid leaching showed transitional behavior--slowed relative to that expected from a second-order reaction relative to that on the gibbsite and silica but faster than those on the kaolinites. The most striking result of the reaction was the marked increase in the rate of reaction of a constant amount of hydrazine as the amount of clay was increased. The increase was apparent (in spite of the water inhibition at high conversions) over a 2 order of magnitude variation of the clay weight. The weight dependence was taken to indicate that the role of the clay is very important, that the number of reactive centers is very small, or that they may be deactivated over the course of the reaction. In contrast to the strong dependence on overall amount of clay, the variation of amounts of putative oxidizing centers, such as structural Fe(III), admixed TiO2 or Fe2O3, or O- centers, did not result in alteration of the rate commensurate with the degree of variation of the entity in question. Surface iron does play some role, however, as samples that were pretreated with a reducing agent were less active as catalysts than the parent material. These results were taken to indicate either that the various centers interact to such a degree that they cannot be considered independently or that the reaction might proceed by way of surface complexation, rather than single electron transfers.

  11. Addressing Ozone Layer Depletion

    EPA Pesticide Factsheets

    Access information on EPA's efforts to address ozone layer depletion through regulations, collaborations with stakeholders, international treaties, partnerships with the private sector, and enforcement actions under Title VI of the Clean Air Act.

  12. The suppressor of AAC2 Lethality SAL1 modulates sensitivity of heterologously expressed artemia ADP/ATP carrier to bongkrekate in yeast.

    PubMed

    Wysocka-Kapcinska, Monika; Torocsik, Beata; Turiak, Lilla; Tsaprailis, George; David, Cynthia L; Hunt, Andrea M; Vekey, Karoly; Adam-Vizi, Vera; Kucharczyk, Roza; Chinopoulos, Christos

    2013-01-01

    The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner.

  13. Sal k 4, a new allergen of Salsola kali, is profilin: a predictive value of conserved conformational regions in cross-reactivity with other plant-derived profilins.

    PubMed

    Assarehzadegan, Mohammad Ali; Amini, Akram; Sankian, Mojtaba; Tehrani, Mohsen; Jabbari, Farahzad; Varasteh, Abdolreza

    2010-01-01

    The aim of this study was to investigate a new allergen of Salsola kali, Sal k 4, and to investigate the predictive value of the conserved conformational regions in cross-reactivity with other plant-derived profilins. The Sal k 4-coding sequence was cloned, expressed, and purified by one-step Ni2+ affinity chromatography to recover high-purity target protein. We assessed cross-reactivity and predicted conserved conformational regions among rSal k 4 and other plant-derived profilins. Immunodetection and inhibition assays using 30 individual sera from S. kali allergic patients indicated that purified rSal k 4 might be the same as that in the crude extract. The results of inhibition assays among rSal k 4 and other plant-derived profilins were in accordance with the homology of the predicted conserved conformational regions. Amino acid sequence homology analysis showed that a high degree of IgE cross-reactivity among plant-derived profilins might depend on the predicted conserved conformational regions.

  14. Characterization of sal(A), a Novel Gene Responsible for Lincosamide and Streptogramin A Resistance in Staphylococcus sciuri

    PubMed Central

    Hot, Chloé; Berthet, Nicolas

    2014-01-01

    Natural resistance to lincosamides and streptogramins A (LSA), which is a species characteristic of Bacillus subtilis and Enterococcus faecalis, has never been documented in the Staphylococcus genus. We investigate here the molecular basis of the LSA phenotype exhibited by seven reference strains of Staphylococcus sciuri, including the type strains of the three described subspecies. By whole-genome sequencing of strain ATCC 29059, we identified a candidate gene that encodes an ATP-binding cassette protein similar to the Lsa and VmlR resistance determinants. Isolation and reverse transcription-quantitative PCR (qRT-PCR) expression studies confirmed that Sal(A) can confer a moderate resistance to lincosamides (8 times the MIC of lincomycin) and a high-level resistance to streptogramins A (64 times the MIC of pristinamycin II). The chromosomal location of sal(A) between two housekeeping genes of the staphylococcal core genome supports the gene's ancient origins and thus innate resistance to these antimicrobials within S. sciuri subspecies. PMID:24687494

  15. Luminescence properties of Sm, Tb(Sal)3Phen complex in polyvinyl alcohol: an approach for white-light emission

    NASA Astrophysics Data System (ADS)

    Kaur, Gagandeep; Rai, S. B.

    2011-10-01

    Polyvinyl alcohol polymer films doped with Sm,Tb(Sal)3Phen complexes have been synthesized using solution casting technique. An enhancement in absorption intensity is observed revealing the encapsulation of rare earth ions by salicylic acid (Sal)/1,10 phenanthroline (Phen) complex. Photoluminescence spectra of the co-doped samples were examined by varying the concentration of Tb3+ keeping concentration of Sm3+ ions fixed and vice-versa. It is found that the polymer samples emit a combination of blue, green and orange-red wavelengths tunable to white light when excited with 355 nm radiation. The emission spectra also show a self-quenching effect at higher concentration of Sm3+ ions. An efficient energy transfer was observed from Tb3+ : 5D4 → Sm3+ : 4G9/2. The reason for the enhancement in fluorescence intensities of Sm3+ in the co-doped polymer sample is the intermolecular as well as the intramolecular energy transfer.

  16. The Air We Breathe

    NASA Technical Reports Server (NTRS)

    Davila, Dina

    2010-01-01

    Topics discussed include NASA mission to pioneer the future in space exploration, scientific discovery and aeronautics research; the role of Earth's atmosphere, atmospheric gases, layers of the Earth's atmosphere, ozone layer, air pollution, effects of air pollution on people, the Greenhouse Effect, and breathing on the International Space Station.

  17. The Atmospheric Boundary Layer

    ERIC Educational Resources Information Center

    Tennekes, Hendrik

    1974-01-01

    Discusses some important parameters of the boundary layer and effects of turbulence on the circulation and energy dissipation of the atmosphere. Indicates that boundary-layer research plays an important role in long-term forecasting and the study of air-pollution meteorology. (CC)

  18. Concentrations of Semivolatile Organic Compounds Associated with African Dust Air Masses in Mali, Cape Verde, Trinidad and Tobago, and the U.S. Virgin Islands, 2001-2008

    USGS Publications Warehouse

    Garrison, Virginia H.; Foreman, William T.; Genualdi, Susan A.; Majewski, Michael S.; Mohammed, Azad; Simonich, Staci Massey

    2011-01-01

    Every year, billions of tons of fine particles are eroded from the surface of the Sahara Desert and the Sahel of West Africa, lifted into the atmosphere by convective storms, and transported thousands of kilometers downwind. Most of the dust is carried west to the Americas and the Caribbean in the Saharan Air Layer (SAL). Dust air masses predominately impact northern South America during the Northern Hemisphere winter and the Caribbean and Southeastern United States in summer. Dust concentrations vary considerably temporally and spatially. In a dust source region (Mali), concentrations range from background levels of 575 micrograms per cubic meter (mu/u g per m3) to 13,000 mu/u g per m3 when visibility degrades to a few meters (Gillies and others, 1996). In the Caribbean, concentrations of 200 to 600 mu/u g per m3 in the mid-Atlantic and Barbados (Prospero and others, 1981; Talbot and others, 1986), 3 to 20 mu/u g per m3 in the Caribbean (Prospero and Nees, 1986; Perry and others, 1997); and >100 mu/u g per m3 in the Virgin Islands (this dataset) have been reported during African dust conditions. Mean dust particle size decreases as the SAL traverses from West Africa to the Caribbean and Americas as a result of gravitational settling. Mean particle size reaching the Caribbean is <1 micrometer (mu/u m) (Perry and others, 1997), and even finer particles are carried into Central America, the Southeastern United States, and maritime Canada. Particles less than 2.5 mu/u m diameter (termed PM2.5) can be inhaled deeply into human lungs. A large body of literature has shown that increased PM2.5 concentrations are linked to increased cardiovascular/respiratory morbidity and mortality (for example, Dockery and others, 1993; Penn and others, 2005).

  19. A numerical solution of the Navier-Stokes equations for chemically nonequilibrium, merged stagnation shock layers on spheres and two-dimensional cylinders in air

    NASA Technical Reports Server (NTRS)

    Johnston, K. D.; Hendricks, W. L.

    1978-01-01

    Results of solving the Navier-Stokes equations for chemically nonequilibrium, merged stagnation shock layers on spheres and two-dimensional cylinders are presented. The effects of wall catalysis and slip are also examined. The thin shock layer assumption is not made, and the thick viscous shock is allowed to develop within the computational domain. The results show good comparison with existing data. Due to the more pronounced merging of shock layer and boundary layer for the sphere, the heating rates for spheres become higher than those for cylinders as the altitude is increased.

  20. VERIFICATION OF SURFACE LAYER OZONE FORECASTS IN THE NOAA/EPA AIR QUALITY FORECAST SYSTEM IN DIFFERENT REGIONS UNDER DIFFERENT SYNOPTIC SCENARIOS

    EPA Science Inventory

    An air quality forecast (AQF) system has been established at NOAA/NCEP since 2003 as a collaborative effort of NOAA and EPA. The system is based on NCEP's Eta mesoscale meteorological model and EPA's CMAQ air quality model (Davidson et al, 2004). The vision behind this system is ...

  1. Air Pollution: Current and Future Challenges

    EPA Pesticide Factsheets

    Despite the dramatic progress to date, air pollution continues to threaten Americans’ health and welfare. The main obstacles are climate change, conventional air pollution, and ozone layer depletion.

  2. Clean Air Act Text

    EPA Pesticide Factsheets

    The Clean Air Act is the law that defines EPA's responsibilities for protecting and improving the nation's air quality and the stratospheric ozone layer. The last major change in the law, the Clean Air Act Amendments of 1990, enacted in 1990 by Congress.

  3. /Air Atmospheres

    NASA Astrophysics Data System (ADS)

    Emami, Samar; Sohn, Hong Yong; Kim, Hang Goo

    2014-08-01

    Molten magnesium oxidizes rapidly when exposed to air causing melt loss and handling difficulties. The use of certain additive gases such as SF6, SO2, and CO2 to form a protective MgO layer over a magnesium melt has been proposed. The oxidation behavior of molten magnesium in air containing various concentrations of SF6 was investigated. Measurements of the kinetics of the oxide layer growth at various SF6 concentrations in air and temperatures were made. Experiments were performed using a thermogravimetric analysis unit in the temperature range of 943 K to 1043 K (670 °C to 770 °C). Results showed that a thin, coherent, and protective MgF2 layer was formed under SF6/Air mixtures, with a thickness ranging from 300 nm to 3 μm depending on SF6 concentration, temperature, and exposure time. Rate parameters were calculated and a model for the process was developed. The morphology and composition of the surface films were studied using scanning electron microscope and energy-dispersive spectroscope.

  4. Multiple layer insulation cover

    DOEpatents

    Farrell, James J.; Donohoe, Anthony J.

    1981-11-03

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  5. High-mobility and air-stable single-layer WS2 field-effect transistors sandwiched between chemical vapor deposition-grown hexagonal BN films

    PubMed Central

    Iqbal, M Waqas; Iqbal, M Zahir; Khan, M Farooq; Shehzad, M Arslan; Seo, Yongho; Park, Jong Hyun; Hwang, Chanyong; Eom, Jonghwa

    2015-01-01

    An emerging electronic material as one of transition metal dichalcogenides (TMDCs), tungsten disulfide (WS2) can be exfoliated as an atomically thin layer and can compensate for the drawback of graphene originating from a gapless band structure. A direct bandgap, which is obtainable in single-layer WS2, is an attractive characteristic for developing optoelectronic devices, as well as field-effect transistors. However, its relatively low mobility and electrical characteristics susceptible to environments remain obstacles for the use of device materials. Here, we demonstrate remarkable improvement in the electrical characteristics of single-layer WS2 field-effect transistor (SL-WS2 FET) using chemical vapor deposition (CVD)-grown hexagonal BN (h-BN). SL-WS2 FET sandwiched between CVD-grown h-BN films shows unprecedented high mobility of 214 cm2/Vs at room temperature. The mobility of a SL-WS2 FET has been found to be 486 cm2/Vs at 5 K. The ON/OFF ratio of output current is ~107 at room temperature. Apart from an ideal substrate for WS2 FET, CVD-grown h-BN film also provides a protection layer against unwanted influence by gas environments. The h-BN/SL-WS2/h-BN sandwich structure offers a way to develop high-quality durable single-layer TMDCs electronic devices. PMID:26030008

  6. Stimuli responsive hybrid magnets: tuning the photoinduced spin-crossover in Fe(III) complexes inserted into layered magnets.

    PubMed

    Clemente-León, Miguel; Coronado, Eugenio; López-Jordà, Maurici; Waerenborgh, João C; Desplanches, Cédric; Wang, Hongfeng; Létard, Jean-François; Hauser, Andreas; Tissot, Antoine

    2013-06-12

    The insertion of a [Fe(sal2-trien)](+) complex cation into a 2D oxalate network in the presence of different solvents results in a family of hybrid magnets with coexistence of magnetic ordering and photoinduced spin-crossover (LIESST effect) in compounds [Fe(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]·CHCl3 (1·CHCl3), [Fe(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]·CHBr3 (1·CHBr3), and [Fe(III)(sal2-trien)][Mn(II)Cr(III)(ox)3]·CH2Br2 (1·CH2Br2). The three compounds crystallize in a 2D honeycomb anionic layer formed by Mn(II) and Cr(III) ions linked through oxalate ligands and a layer of [Fe(sal2-trien)](+) complexes and solvent molecules (CHCl3, CHBr3, or CH2Br2) intercalated between the 2D oxalate network. The magnetic properties and Mössbauer spectroscopy indicate that they undergo long-range ferromagnetic ordering at 5.6 K and a spin crossover of the intercalated [Fe(sal2-trien)](+) complexes at different temperatures T1/2. The three compounds present a LIESST effect with a relaxation temperature TLIESST inversely proportional to T1/2. The isostructural paramagnetic compound, [Fe(III)(sal2-trien)][Zn(II)Cr(III)(ox)3]·CH2Cl2 (2·CH2Cl2) was also prepared. This compound presents a partial spin crossover of the inserted Fe(III) complex as well as a LIESST effect. Finally, spectroscopic characterization of the Fe(III) doped compound [Ga0.99Fe0.01(sal2trien)][Mn(II)Cr(III)(ox)3]·CH2Cl2 (3·CH2Cl2) shows a gradual and complete thermal spin crossover and a LIESST effect on the isolated Fe(III) complexes. This result confirms that cooperativity is not a necessary condition to observe the LIESST effect in an Fe(III) compound.

  7. Air Modeling - Observational Meteorological Data

    EPA Pesticide Factsheets

    Observed meteorological data for use in air quality modeling consist of physical parameters that are measured directly by instrumentation, and include temperature, dew point, wind direction, wind speed, cloud cover, cloud layer(s), ceiling height,

  8. Investigation of the hygroscopic growth of self-assembled layers of N-alkyl-N-methylpyrrolidinium bromides at the interface between air and organic salt

    SciTech Connect

    Shin, Yongsoon; Baker, Gary A.; Wang, Li Q.; Exarhos, Gregory J.

    2008-04-01

    We report on the hygroscopic growth of self-assembled lamellae, composed of N-alkyl-N-methylpyrrolidinium bromide (CnMPB; n = 10, 12, 14, 16, 18) surfactant molecules, spontaneously formed at the interface between ambient air and the low-melting organic salt tetrabutylammonium acetate (TBAAc). The organization process to form well-defined hygroscopic bilayer patterns at the air/TBAAc interface was investigated using a combination of time-dependent X-ray diffraction (XRD) and carbon-13 cross-polarization magic angle spinning nuclear magnetic resonance (13C CP/MAS NMR) spectroscopy. CnMPB surfactants containing the highest alkyl chain lengths studied (n = 16, 18) formed highly ordered, fully-interdigitated bilayer patterns with an all-trans conformation of interior methylene carbons. In contrast, CnMPB surfactants with shorter alkane chains (n = 10, 12, 14) in this series formed less-ordered bilayer arrangements with mixed trans/gauche aliphatic character. The lamellar patterns became increasingly ordered with longer exposure to humid air at the air/salt interface.

  9. Air-stable conversion of separated carbon nanotube thin-film transistors from p-type to n-type using atomic layer deposition of high-κ oxide and its application in CMOS logic circuits.

    PubMed

    Zhang, Jialu; Wang, Chuan; Fu, Yue; Che, Yuchi; Zhou, Chongwu

    2011-04-26

    Due to extraordinary electrical properties, preseparated, high purity semiconducting carbon nanotubes hold great potential for thin-film transistors (TFTs) and integrated circuit applications. One of the main challenges it still faces is the fabrication of air-stable n-type nanotube TFTs with industry-compatible techniques. Here in this paper, we report a novel and highly reliable method of converting the as-made p-type TFTs using preseparated semiconducting nanotubes into air-stable n-type transistors by adding a high-κ oxide passivation layer using atomic layer deposition (ALD). The n-type devices exhibit symmetric electrical performance compared with the p-type devices in terms of on-current, on/off ratio, and device mobility. Various factors affecting the conversion process, including ALD temperature, metal contact material, and channel length, have also been systematically studied by a series of designed experiments. A complementary metal-oxide-semiconductor (CMOS) inverter with rail-to-rail output, symmetric input/output behavior, and large noise margin has been further demonstrated. The excellent performance gives us the feasibility of cascading multiple stages of logic blocks and larger scale integration. Our approach can serve as the critical foundation for future nanotube-based thin-film macroelectronics.

  10. Sand and clay mineralogy of sal forest soils of the Doon Siwalik Himalayas

    NASA Astrophysics Data System (ADS)

    Mukesh; Manhas, R. K.; Tripathi, A. K.; Raina, A. K.; Gupta, M. K.; Kamboj, S. K.

    2011-02-01

    The peteromineralogical characterization of the soil was carried out for the 12 soil profiles exposed in the Shorea robusta dominated forests of the Siwalik forest division, Dehradun. The quartz was observed as the dominating light mineral fraction (64-80%) in all the profiles studied. Biotite, hornblende, zircon, tourmaline, rutile and opaques comprising of iron minerals constituted the heavy mineral fraction (20%). The mineralogy of both the sand and clay fractions revealed a mixed mineralogy. The clay minerals in the order of their dominance were vermiculite, illite, kaolinite and mixed layer minerals. The presence of vermiculite and illite in appreciable quantities indicates that these were synthesized from the K-rich soil solution, as orthoclase and micas were present in significant quantities in the sand minerals. The mineral suites identified in the study shows that the geological, climatological and topographical factors of the region collectively played a dominant role in their formation and transformation. After critical appraisal of the results, it may be deduced that the mineralogical composition, physicochemical properties and total elemental analysis of the soils do not show any deficiency of the bases and other plant nutrients in general. The inherent fertility of the soil is good as indicated by the sand and clay mineralogy of the soil and the biotite and feldspar together with the mica is an important source of nutrients for the vegetation in the soils of the Doon valley.

  11. Synthesis, crystal structure and magnetic properties of trinuclear chromium(III) basic carboxylate assembly: [Cr3O(salH)7(H2O)2] (salH2=salicylic acid), a new member of [Cr3O] family

    NASA Astrophysics Data System (ADS)

    Dong, Jinlong; Liu, Bin; Yang, Binsheng

    2016-07-01

    Synthesizing a novel trinuclear chromium(III) basic carboxylate complex could give rise to new materials with interesting properties. Complex [Cr3O(salH)7(H2O)2] is formed in a one-pot, self-assembly reaction when the inert reaction mixture is exposed to dioxygen. The structural property of the complex has been acquired by single-crystal X-ray crystallography and further characterized by elemental analysis (EA), infrared (IR), UV-Visible (UV-Vis), fluorescence spectroscopy and thermo gravimetric and differential thermal analysis (TG-DTA). X-ray structural analysis shows a slightly distorted equilateral of the Cr triangle. The most important feature of the title complex is the unusual framework of the [Cr3O] family due to a terminal Ph(OH)CO2- ion of Cr(2) center, which is unique among the structurally characterized (μ3-oxo)-trichromium(III) complexes. Variable-temperature magnetic susceptibility studies indicate that the total spin value of the ground state is 1/2.

  12. Investigations of Scalar Transfer Coefficients in Fog During the Coupled Boundary Layers and Air-Sea Transfer Experiment: A Case Study

    DTIC Science & Technology

    2004-09-01

    mentioned, the disadvantage is that the important processes in fog formation take place below one meter (Wang 2004; Binhua 1985; Turton and Brown...formula under these conditions by examining the physical processes that are unique to these boundary layers. Particular attention will be paid to the...to moderate wind conditions. The experiment was designed to measure fluxes and their associated profiles so that every term within the turbulent

  13. Transition within a Hypervelocity Boundary Layer on a 5-degree Half-Angle Cone in Freestream Air/CO2 Mixtures

    DTIC Science & Technology

    2013-01-01

    cells by 301 cells in the streamwise and wall-normal directions. The stability analyses are performed using the PSE -Chem solver, which is also part...of the STABL software suite. PSE -Chem (Johnson and Candler 2005) solves the reacting, two-dimensional, axi-symmetric, linear parabolized stability...equations to predict the amplification of disturbances as they interact with the boundary layer. The PSE -Chem solver includes finite-rate chemistry

  14. Fe-Cluster Pushing Electrons to N-Doped Graphitic Layers with Fe3C(Fe) Hybrid Nanostructure to Enhance O2 Reduction Catalysis of Zn-Air Batteries.

    PubMed

    Yang, Jie; Hu, Jiangtao; Weng, Mouyi; Tan, Rui; Tian, Leilei; Yang, Jinlong; Amine, Joseph; Zheng, Jiaxin; Chen, Haibiao; Pan, Feng

    2017-02-08

    Non-noble metal catalysts with catalytic activity toward oxygen reduction reaction (ORR) comparable or even superior to that of Pt/C are extremely important for the wide application of metal-air batteries and fuel cells. Here, we develop a simple and controllable strategy to synthesize Fe-cluster embedded in Fe3C nanoparticles (designated as Fe3C(Fe)) encased in nitrogen-doped graphitic layers (NDGLs) with graphitic shells as a novel hybrid nanostructure as an effective ORR catalyst by directly pyrolyzing a mixture of Prussian blue (PB) and glucose. The pyrolysis temperature was found to be the key parameter for obtaining a stable Fe3C(Fe)@NDGL core-shell nanostructure with an optimized content of nitrogen. The optimized Fe3C(Fe)@NDGL catalyst showed high catalytic performance of ORR comparable to that of the Pt/C (20 wt %) catalyst and better stability than that of the Pt/C catalyst in alkaline electrolyte. According to the experimental results and first principle calculation, the high activity of the Fe3C(Fe)@NDGL catalyst can be ascribed to the synergistic effect of an adequate content of nitrogen doping in graphitic carbon shells and Fe-cluster pushing electrons to NDGL. A zinc-air battery utilizing the Fe3C(Fe)@NDGL catalyst demonstrated a maximum power density of 186 mW cm(-2), which is slightly higher than that of a zinc-air battery utilizing the commercial Pt/C catalyst (167 mW cm(-2)), mostly because of the large surface area of the N-doped graphitic carbon shells. Theoretical calculation verified that O2 molecules can spontaneously adsorb on both pristine and nitrogen doped graphene surfaces and then quickly diffuse to the catalytically active nitrogen sites. Our catalyst can potentially become a promising replacement for Pt catalysts in metal-air batteries and fuel cells.

  15. The simultaneous electrochemical detection of catechol and hydroquinone with [Cu(Sal-β-Ala)(3,5-DMPz)2]/SWCNTs/GCE.

    PubMed

    Alshahrani, Lina Abdullah; Li, Xi; Luo, Hui; Yang, Linlin; Wang, Mengmeng; Yan, Songling; Liu, Peng; Yang, Yuqin; Li, Quanhua

    2014-11-25

    A glassy carbon electrode was modified with a copper(II) complex [Cu(Sal-β-Ala) (3,5-DMPz)2] (Sal = salicylaldehyde, β-Ala = β-alanine, 3,5-DMPz = 3,5-dimethylpyrazole) and single-walled carbon nanotubes (SWCNTs). The modified electrode was used to detect catechol (CT) and hydroquinone (HQ) and exhibited good electrocatalytic activities toward the oxidation of CT and HQ. The peak currents were linear with the CT and HQ concentrations over the range of 5-215 μmol·L(-1) and 5-370 μmol·L(-1) with corresponding detection limits of 3.5 μmol·L(-1) and 1.46 μmol·L(-1) (S/N = 3) respectively. Moreover, the modified electrode exhibited good sensitivity, stability and reproducibility for the determination of CT and HQ, indicating the promising applications of the modified electrode in real sample analysis.

  16. The Simultaneous Electrochemical Detection of Catechol and Hydroquinone with [Cu(Sal-β-Ala)(3,5-DMPz)2]/SWCNTs/GCE

    PubMed Central

    Alshahrani, Lina Abdullah; Li, Xi; Luo, Hui; Yang, Linlin; Wang, Mengmeng; Yan, Songling; Liu, Peng; Yang, Yuqin; Li, Quanhua

    2014-01-01

    A glassy carbon electrode was modified with a copper(II) complex [Cu(Sal-β-Ala) (3,5-DMPz)2] (Sal = salicylaldehyde, β-Ala = β-alanine, 3,5-DMPz = 3,5-dimethylpyrazole) and single-walled carbon nanotubes (SWCNTs). The modified electrode was used to detect catechol (CT) and hydroquinone (HQ) and exhibited good electrocatalytic activities toward the oxidation of CT and HQ. The peak currents were linear with the CT and HQ concentrations over the range of 5–215 μmol·L−1 and 5–370 μmol·L−1 with corresponding detection limits of 3.5 μmol·L−1 and 1.46 μmol·L−1 (S/N = 3) respectively. Moreover, the modified electrode exhibited good sensitivity, stability and reproducibility for the determination of CT and HQ, indicating the promising applications of the modified electrode in real sample analysis. PMID:25429411

  17. The sea-air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): concentrations and evasion flux.

    PubMed

    Bagnato, E; Sproveri, M; Barra, M; Bitetto, M; Bonsignore, M; Calabrese, S; Di Stefano, V; Oliveri, E; Parello, F; Mazzola, S

    2013-11-01

    The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hgatm concentrations of about 1.5±0.4 (range 0.9-3.1) and 2.1±0.98 (range 1.1-3.1) ng m(-3) for the two seasons, respectively. These data are somewhat higher than the background Hg atm value measured over the land (range 1.1±0.3 ng m(-3)) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6±0.3 (unpolluted site) to 72±0.1 (polluted site of the basin) ng m(-2) h(-1). By extending these measurements to the entire area of the Augusta basin (~23.5 km(2)), we calculated a total sea-air Hg evasion flux of about 9.7±0.1 g d(-1) (~0.004 tyr(-1)), accounting for ~0.0002% of the global Hg oceanic evasion (2000 tyr(-1)). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea-air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element.

  18. Finite difference calculation of acoustic streaming including the boundary layer phenomena in an ultrasonic air pump on graphics processing unit array

    NASA Astrophysics Data System (ADS)

    Wada, Yuji; Koyama, Daisuke; Nakamura, Kentaro

    2012-09-01

    Direct finite difference fluid simulation of acoustic streaming on the fine-meshed threedimension model by graphics processing unit (GPU)-oriented calculation array is discussed. Airflows due to the acoustic traveling wave are induced when an intense sound field is generated in a gap between a bending transducer and a reflector. Calculation results showed good agreement with the measurements in the pressure distribution. In addition to that, several flow-vortices were observed near the boundary of the reflector and the transducer, which have been often discussed in acoustic tube near the boundary, and have not yet been observed in the calculation in the ultrasonic air pump of this type.

  19. Recirculating electric air filter

    DOEpatents

    Bergman, Werner

    1986-01-01

    An electric air filter cartridge has a cylindrical inner high voltage eleode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  20. Recirculating electric air filter

    DOEpatents

    Bergman, W.

    1985-01-09

    An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  1. Burning Graphene Layer-by-Layer

    NASA Astrophysics Data System (ADS)

    Ermakov, Victor A.; Alaferdov, Andrei V.; Vaz, Alfredo R.; Perim, Eric; Autreto, Pedro A. S.; Paupitz, Ricardo; Galvao, Douglas S.; Moshkalev, Stanislav A.

    2015-06-01

    Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in “cold-wall” reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

  2. Burning Graphene Layer-by-Layer

    PubMed Central

    Ermakov, Victor A.; Alaferdov, Andrei V.; Vaz, Alfredo R.; Perim, Eric; Autreto, Pedro A. S.; Paupitz, Ricardo; Galvao, Douglas S.; Moshkalev, Stanislav A.

    2015-01-01

    Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in “cold-wall” reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material. PMID:26100466

  3. Solving the AI Planning Plus Scheduling Problem Using Model Checking via Automatic Translation from the Abstract Plan Preparation Language (APPL) to the Symbolic Analysis Laboratory (SAL)

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Munoz, Cesar A.; Siminiceanu, Radu I.

    2007-01-01

    This paper describes a translator from a new planning language named the Abstract Plan Preparation Language (APPL) to the Symbolic Analysis Laboratory (SAL) model checker. This translator has been developed in support of the Spacecraft Autonomy for Vehicles and Habitats (SAVH) project sponsored by the Exploration Technology Development Program, which is seeking to mature autonomy technology for the vehicles and operations centers of Project Constellation.

  4. Boundary Layer Control on Airfoils.

    ERIC Educational Resources Information Center

    Gerhab, George; Eastlake, Charles

    1991-01-01

    A phenomena, boundary layer control (BLC), produced when visualizing the fluidlike flow of air is described. The use of BLC in modifying aerodynamic characteristics of airfoils, race cars, and boats is discussed. (KR)

  5. WEATHER_Layered-Precipitable-Water

    Atmospheric Science Data Center

    2016-06-23

    ... TOVS (HIRS) clear sky radiances Radiosonde GPS (after 1995) AIRS Level 2 TPW and Layered PW Spatial ... Parameters:  Precipitable Water Order Data:  Earthdata Search:  Earthdata Search SCAR-B ...

  6. Substrate Specificity of the Bacillus subtilis BY-Kinase PtkA Is Controlled by Alternative Activators: TkmA and SalA

    PubMed Central

    Derouiche, Abderahmane; Shi, Lei; Kalantari, Aida; Mijakovic, Ivan

    2016-01-01

    Bacterial protein-tyrosine kinases (BY-kinases) are known to regulate different aspects of bacterial physiology, by phosphorylating cellular protein substrates. Physiological cues that trigger BY-kinases activity are largely unexplored. In Proteobacteria, BY-kinases contain a cytosol-exposed catalytic domain and a transmembrane activator domain in a single polypeptide chain. In Firmicutes, the BY-kinase catalytic domain and the transmembrane activator domain exist as separate polypeptides. We have previously speculated that this architecture might enable the Firmicutes BY-kinases to interact with alternative activators, and thus account for the observed ability of these kinases to phosphorylate several distinct classes of protein substrates. Here, we present experimental evidence that supports this hypothesis. We focus on the model Firmicute-type BY-kinase PtkA from Bacillus subtilis, known to phosphorylate several different protein substrates. We demonstrate that the transcriptional regulator SalA, hitherto known as a substrate of PtkA, can also act as a PtkA activator. In doing so, SalA competes with the canonical PtkA activator, TkmA. Our results suggest that the respective interactions of SalA and TkmA with PtkA favor phosphorylation of different protein substrates in vivo and in vitro. This observation may contribute to explaining how specificity is established in the seemingly promiscuous interactions of BY-kinases with their cellular substrates. PMID:27725816

  7. Undoped Buffer Layer Development.

    DTIC Science & Technology

    1984-01-01

    boiled for several hours in aqua regia , followed by boiling for several more hours in deionized water before being dried in air and loaded into the...different from Report) 1S. SUPPLEMENTARY NOTES it. IKy WORDS (Canal... an reverse 4aaIo It eesarav d Ientify by block nuinbr) Epitaxial layer MBE

  8. Mercury in the marine boundary layer and seawater of the South China Sea: Concentrations, sea/air flux, and implication for land outflow

    NASA Astrophysics Data System (ADS)

    Fu, Xuewu; Feng, Xinbin; Zhang, Gan; Xu, Weihai; Li, Xiangdong; Yao, Hen; Liang, Peng; Li, Jun; Sommar, Jonas; Yin, Runsheng; Liu, Na

    2010-03-01

    Using R/V Shiyan 3 as a sampling platform, measurements of gaseous elemental mercury (GEM), surface seawater total mercury (THg), methyl mercury (MeHg), and dissolved gaseous mercury (DGM) were carried out above and in the South China Sea (SCS). Measurements were collected for 2 weeks (10 to 28 August 2007) during an oceanographic expedition, which circumnavigated the northern SCS from Guangzhou (Canton), Hainan Inland, the Philippines, and back to Guangzhou. GEM concentrations over the northern SCS ranged from 1.04 to 6.75 ng m-3 (mean: 2.62 ng m-3, median: 2.24 ng m-3). The spatial distribution of GEM was characterized by elevated concentrations near the coastal sites adjacent to mainland China and lower concentrations at stations in the open sea. Trajectory analysis revealed that high concentrations of GEM were generally related to air masses from south China and the Indochina peninsula, while lower concentrations of GEM were related to air masses from the open sea area, reflecting great Hg emissions from south China and Indochina peninsula. The mean concentrations of THg, MeHg, and DGM in surface seawater were 1.2 ± 0.3 ng L-1, 0.12 ± 0.05 ng L-1, and 36.5 ± 14.9 pg L-1, respectively. In general, THg and MeHg levels in the northern SCS were higher compared to results reported from most other oceans/seas. Elevated THg levels in the study area were likely attributed to significant Hg delivery from surrounding areas of the SCS primarily via atmospheric deposition and riverine input, whereas other sources like in situ production by various biotic and abiotic processes may be important for MeHg. Average sea/air flux of Hg in the study area was estimated using a gas exchange method (4.5 ± 3.4 ng m-2 h-1). This value was comparable to those from other coastal areas and generally higher than those from open sea environments, which may be attributed to the reemission of Hg previously transported to this area.

  9. MicroRNA-181b inhibits cellular proliferation and invasion of glioma cells via targeting Sal-like protein 4.

    PubMed

    Zhou, Yu; Peng, Yong; Liu, Min; Jiang, Yugang

    2016-11-17

    MicroRNAs (miRs), a class of 18-25 nucleotides in length non-coding RNAs, are able to suppress gene expression by targeting complementary regions of mRNAs and inhibiting protein translation Recently, miR-181b was found to playa suppressive role in glioma, but the regulatory mechanism of miR-181b in the malignant phenotypes of glioma cells remains largely unclear. Here we found that miR-181b was significantly downregulated in glioma tissues when compared with normal brain tissues, and decreased miR-181b levels were significantly associated with high pathology grade and poor prognosis of patients with glioma. Moreover, miR-181b was also downregulated in glioma cell lines (U87, SHG44, U373, and U251) compared to normal astrocytes. Overexpression of miR-181b significantly decreased the proliferation, migration, and invasion of glioma U251 cells. Sal-like protein 4 (SALL4) was identified as a novel target gene of miR-181b in U251 cells. The expression of SALL4 was significantly upregulated in glioma tissues and cell lines, and an inverse correlation was observed between the miR-181b and SALL4 expression levels in glioma. Further investigation showed that the protein expression of SALL4 was negatively regulated by miR-181b in U251 cells. Knockdown of SALL4 significantly inhibited the proliferation, migration and invasion of U251 cells, while overexpression of SALL4 effectively reversed the suppressive effects of miR-181b on these malignant phenotypes of U251 cells. In conclusion, our study demonstrates that miR-181b has suppressive effects on the malignant phenotypes of glioma cells, partly at least, via directly targeting SALL4. Therefore, the miR-181b/SALL4 axis may become a potential therapeutic target for glioma.

  10. Incidence of ochratoxin A in rice and dried fruits from Rabat and Salé area, Morocco.

    PubMed

    Zinedine, A; Soriano, J M; Juan, C; Mojemmi, B; Moltó, J C; Bouklouze, A; Cherrah, Y; Idrissi, L; El Aouad, R; Mañes, J

    2007-03-01

    One hundred samples of dried fruits (20 dried raisins, 20 walnuts, 20 peanuts, 20 dried figs and 20 pistachios) and 20 samples of rice purchased from retail shops in the Rabat and Salé area in Morocco were analysed for ochratoxin A (OTA) by immunoaffinity clean-up (IAC) and liquid chromatography (LC) with fluorescence detection. The limit of quantification (LOQ) (S/N = 10:1) of OTA was 0.02 ng g(-1) in rice, 0.03 ng g(-1) in pistachio, peanut and walnut, and 0.03 ng g(-1) in dried raisins and dried figs. The incidences of occurrence of OTA in dried raisins, walnuts, peanuts, dried figs and rice were 30, 35, 25, 65 and 90%, respectively. Analytical results showed that pistachio samples contained no detectable OTA, but concentrations ranged from 0.02 +/- 0.01 to 32.4 +/- 2.10 ng g(-1) in rice, from 0.10 +/- 0.05 to 2.36 +/- 0.75 in peanut, from 0.03 +/- 0.01 to 1.42 +/- 0.45 in dried figs, from 0.05 +/- 0.02 to 4.95 +/- 0.02 in dried raisins, and from 0.04 +/- 0.01 to 0.23 +/- 0.05 in walnuts. The results also showed that 15% of the total number of rice samples analysed exceeded the 2002 regulatory limit set by European Union regulations for cereals. This is the first report on the occurrence of OTA in dried fruits and rice available in Morocco.

  11. Effects of dissolved organic matter (DOM) at environmentally relevant carbon concentrations on atrazine degradation by Chelatobacter heintzii SalB.

    PubMed

    Cheyns, Karlien; Calcoen, Jasper; Martin-Laurent, Fabrice; Bru, David; Smolders, Erik; Springael, Dirk

    2012-09-01

    The dissolved organic matter (DOM) is the term used for organic components of natural origin present in the soil solution and is probably the most available C-source that primes microbial activity in subsoils. Contrasting effects of organic C components on pesticide degradation have been reported; however, most studies have used model organic compounds with compositions and concentrations which differ substantially from those found in the environment. Degradation of atrazine (AT) by Chelatobacter heintzii SalB was monitored in liquid batch assays in the absence or presence of well-defined model C compounds (glucose, gluconate and citrate) as model DOM (mDOM) or complex, less-defined, environmental DOM solutions (eDOM: isolated humic substances, soil and plant residue extracts) at environmentally relevant concentrations. Glucose significantly increased AT degradation rate by more than a factor of 8 at and above 2.5 mg C L( - 1). Optical density measurements showed that this stimulation is related to microbial growth. Gluconate and citrate had no effects unless at non-relevant concentrations (1,000 mg DOC L( - 1)) at which stimulations (gluconate) or inhibitions (citrate) were found. The effects of eDOM added at 10 mg DOC L( - 1) on AT degradation were generally small. The AT degradation time was reduced by factors 1.4-1.9 in the presence of humic acids and eDOM from soils amended with plant residues; however, no effects were found for fulvic acids or eDOM from a soil leachate solution or extracted from unamended peat or forest soil. In conclusion, DOM supplied as both mDOM and eDOM did not inhibit AT degradation at environmentally relevant concentrations, and stimulation can be found for selected DOM samples and this is partly related to its effect on growth.

  12. Analyzing the Effect of Capillary Force on Vibrational Performance of the Cantilever of an Atomic Force Microscope in Tapping Mode with Double Piezoelectric Layers in an Air Environment.

    PubMed

    Nahavandi, Amir; Korayem, Moharam Habibnejad

    2015-10-01

    The aim of this paper is to determine the effects of forces exerted on the cantilever probe tip of an atomic force microscope (AFM). These forces vary according to the separation distance between the probe tip and the surface of the sample being examined. Hence, at a distance away from the surface (farther than d(on)), these forces have an attractive nature and are of Van der Waals type, and when the probe tip is situated in the range of a₀≤ d(ts) ≤ d(on), the capillary force is added to the Van der Waals force. At a distance of d(ts) ≤ a₀, the Van der Waals and capillary forces remain constant at intermolecular distances, and the contact repulsive force repels the probe tip from the surface of sample. The capillary force emerges due to the contact of thin water films with a thickness of h(c) which have accumulated on the sample and probe. Under environmental conditions a layer of water or hydrocarbon often forms between the probe tip and sample. The capillary meniscus can grow until the rate of evaporation equals the rate of condensation. For each of the above forces, different models are presented. The smoothness or roughness of the surfaces and the geometry of the cantilever tip have a significant effect on the modeling of forces applied on the probe tip. Van der Waals and the repulsive forces are considered to be the same in all the simulations, and only the capillary force is altered in order to evaluate the role of this force in the AFM-based modeling. Therefore, in view of the remarkable advantages of the piezoelectric microcantilever and also the extensive applications of the tapping mode, we investigate vibrational motion of the piezoelectric microcantilever in the tapping mode. The cantilever mentioned is entirely covered by two piezoelectric layers that carry out both the actuation of the probe tip and the measuringof its position.

  13. High-resolution visibility and air quality forecasting using multi-layer urban canopy model for highly urbanized Hong Kong and the Pearl River Delta

    NASA Astrophysics Data System (ADS)

    Piu NG, Chak; HAO, Song; Fat LAM, Yun

    2015-04-01

    Visibility is a universally critical element which affects the public in many aspects, including economic activities, health of local citizens and safety of marine transportation and aviation. The Interagency Monitoring of Protected Visual Environments (IMPROVE) visibility equation, an empirical equation developed by USEPA, has been modified by various studies to fit into the application upon the Asian continent including Hong Kong and China. Often these studies focused on the improvement of the existing IMPROVE equation by modifying its particulate speciation using local observation data. In this study, we developed an Integrated Forecast System (IFS) to predict the next-day air quality and visibility using Weather Research and Forecasting model with Building Energy Parameterization and Building Energy Model (WRF-BEP+BEM) and Community Multi-scale Air Quality Model (CMAQ). Unlike the other studies, the core of this study is to include detailed urbanization impacts with calibrated "IMPROVE equation for PRD" into the modeling system for Hong Kong's environs. The ultra-high resolution land cover information (~1km x 1km) from Google images, was digitized into the Geographic Information System (GIS) for preparing the model-ready input for IFS. The NCEP FNL (Final) Operation Global Analysis (FNL) and the Global Forecasting System (GFS) datasets were tested for both hind-cast and forecast cases, in order to calibrate the input of urban parameters in the WRF-BEP+BEM model. The evaluation of model performance with sensitivity cases was performed on sea surface temperature (SST), surface temperature (T), wind speed/direction with the major pollutants (i.e., PM10, PM2.5, NOx, SO2 and O3) using local observation and will be presented/discussed in this paper. References: 1. Y. L. Lee, R. Sequeira, Visibility degradation across Hong Kong its components and their relative contribution. Atmospheric Environment 2001, 35, 5861-5872. doi:10.1016/S1352-2310(01)00395-8 2. R. Zhang, Q

  14. Air Research

    EPA Pesticide Factsheets

    EPA's air research provides the critical science to develop and implement outdoor air regulations under the Clean Air Act and puts new tools and information in the hands of air quality managers and regulators to protect the air we breathe.

  15. Effects of Divalent Cations on Phase Behavior and Structure of a Zwitterionic Phospholipid (DMPC) Mono layer at the Air-Water Interface

    SciTech Connect

    Kewalramani, S.; Hlaing, H.; Ocko, B.M.; Kuzmenko, I.; Fukuto, M.

    2010-01-21

    Effects of divalent cations (Ca{sup 2+}, Mg{sup 2+}, Ni{sup 2+}, and Zn{sup 2+}) on a zwitterionic phospholipid monolayer at the air-water interface are investigated by surface pressure-area isotherms and in situ X-ray scattering. Divalent cations lower the surface pressure for the fluid (LE) to condensed (L{sub 2}) phase transition in a strongly ion-specific manner. Surprisingly, the two-dimensional lattice dimensions and the tilt of the lipids alkyl tails in the L{sub 2} phase show a nearly ion-nonspecific dependence on the excess surface pressure above the transition pressure. An empirical 'universal' relationship was found between the tail tilt and the excess pressure, with the tails in the L{sub 2} phase always displaying a tilt of 29{sup o} at the transition. A practical implication of these results is that, regardless of the divalent cation present, the microscopic details of the lipid tail packing in the L{sub 2} phase can be deduced at any surface pressure once the transition pressure is obtained from isotherms.

  16. Air cathode structure manufacture

    DOEpatents

    Momyer, William R.; Littauer, Ernest L.

    1985-01-01

    An improved air cathode structure for use in primary batteries and the like. The cathode structure includes a matrix active layer, a current collector grid on one face of the matrix active layer, and a porous, nonelectrically conductive separator on the opposite face of the matrix active layer, the collector grid and separator being permanently bonded to the matrix active layer. The separator has a preselected porosity providing low IR losses and high resistance to air flow through the matrix active layer to maintain high bubble pressure during operation of the battery. In the illustrated embodiment, the separator was formed of porous polypropylene. A thin hydrophobic film is provided, in the preferred embodiment, on the current collecting metal grid.

  17. Novel slanted incidence air-coupled ultrasound method for delamination assessment in individual bonding planes of structural multi-layered glued timber laminates.

    PubMed

    Sanabria, Sergio J; Furrer, Roman; Neuenschwander, Jürg; Niemz, Peter; Sennhauser, Urs

    2013-09-01

    Non-destructive assessment of delaminations in glued laminated timber structures is required during their full life cycle. A novel air-coupled ultrasound (ACU) method has been developed, which is able to separately detect delaminations in individual bonding planes of arbitrarily high and long laminated stacks and typically 200 mm wide. The 120 kHz ACU transmitter-receiver pair is positioned at two opposite lateral faces of the sample, with a small inclination with respect to the inspected bonding planes, so that an ultrasound beam is excited at a user-defined refraction angle within the sample, interacting with defects in a limited height portion of the stack. The attenuation of the ultrasound beam transmitted across the defect (negative detection) provided better sensitivity to defects than the scattered fields (positive detection), which are masked by spurious fields. Dedicated finite-difference time-domain (FDTD) simulations provided understanding on the wave propagation and defect detectability limits, with respect to the heterogeneous anisotropic material structure introduced by the curvature of the annual rings in individual timber lamellas. A simplified analytical expression was derived to calculate refraction angles in timber in function of insonification angle and ring angle. Experimental results show that the method is able to detect >20% wide defects in both isotropic material and in glulam with straight year rings, and >50% wide and 100mm long defects in commercial glulam beams. The discrimination of defects from background variability is optimized by normalizing the images with respect to reference defect-free sample sections (normalization) or previous measurements (difference imaging), and by combining readings obtained with distinct ultrasound beam refraction angles (spatial diversity). Future work aims at the development of a tomographic defect inspection by combining the described theoretical and experimental methods.

  18. Large-scale carbonate platform development of Cay Sal Bank, Bahamas, and implications for associated reef geomorphology

    NASA Astrophysics Data System (ADS)

    Purkis, Sam; Kerr, Jeremy; Dempsey, Alexandra; Calhoun, Andrew; Metsamaa, Liisa; Riegl, Bernhard; Kourafalou, Villy; Bruckner, Andrew; Renaud, Philip

    2014-10-01

    The Bahama Archipelago consists of an arcuate chain of carbonate platforms. Average water depths on the platform-tops, such as the Great Bahama Bank (GBB), are typically 10 m or less, with coral reef-rimmed margins, thick sediment accumulations, and the frequent occurrence of islands. There are, however, exceptions. For example, Cay Sal Bank (CSB), a little studied detached Bahamian carbonate platform with depths ranging from 30 to 7 m, is only slightly deeper than the GBB, but devoid of islands, lacks platform-margin coral reefs and holds little sediment on the platform-top; the platform is incipiently drowned. CSB is interesting as it is conspicuously larger (6000 sq. km) than other incipiently drowned platforms in the region, such as Serranilla Bank (1100 sq. km) and the Cat Island platform (1500 sq. km). Field and remote sensing data are assembled to provide insight into the sedimentology and geomorphology of the CSB. The influence of ocean climate, regional hydrodynamics, and Holocene flooding history are investigated to understand why platform-margin coral reef growth on CSB has been unable to keep pace with Holocene sea-level rise. A decade of regional sea-surface temperature data for the Bahamas report CSB to be situated in the same ocean climate regime as GBB. Temperature cannot explain the platform's different morphologies. The Florida Current has been evoked as a possible reason for the immature development of platform-top processes on the CSB, but numeric modeling suggests its influence to be restricted to the deep flanks of the bank. Further, sediment distribution on CSB, including infill patterns of karst depressions, suggest trade winds (easterlies) to drive platform-top hydrodynamics. By assembling a satellite-derived bathymetry map, it can be shown that CSB flooded earlier and at relatively higher rates of Holocene sea-level rise than its neighboring platforms. Flooding history is identified as the most feasible explanation for the atypical

  19. Effectiveness of sal deoiled seed cake as an inducer for protease production from Aeromonas sp. S1 for its application in kitchen wastewater treatment.

    PubMed

    Saini, Vandana; Bhattacharya, Amrik; Gupta, Anshu

    2013-08-01

    The present study is an attempt to demonstrate the feasibility of sal (Shorea robusta) deoiled cake--a forest-based industrial by-product--as a cheaper media supplement for augmented protease production from Aeromonas sp. S1 and application of protease in the treatment of kitchen wastewater. Under optimized conditions, protease production could successfully be enhanced to 5.13-fold (527.5 U mL(-1)) on using sal deoiled seed cake extract (SDOCE), as medium additive, compared to an initial production of 102.7 U mL(-1) in its absence. The culture parameters for optimum production of protease were determined to be incubation time (48 h), pH (7.0), SDOCE concentration (3 % (v/v)), inoculum size (0.3-0.6 % (v/v)), and agitation rate (100 rpm). The enzyme was found to have an optimum pH and temperature of 8.0 and 60 °C, respectively. The protease preparation was tested for treatment of organic-laden kitchen wastewater. After 96 h of wastewater treatment under static condition, enzyme preparation was able to reduce 74 % biological oxygen demand, 37 % total suspended solids, and 41 % oil and grease. The higher and improved level of protease obtained using sal deoiled seed cake-based media hence offers a new approach for value addition to this underutilized biomass through industrial enzyme production. The protease produced using this biomass could also be used as pretreatment tool for remediation of organic-rich food wastewater.

  20. Chromosomal aberrations induced by the restriction endonucleases EcoR I, Pst I, Sal I and Bam HI in CHO cells.

    PubMed

    Zhang, S Z; Dong, W F

    1987-09-01

    4 widely used cohesive end-producing restriction endonucleases (REs), EcoR I, Pst I, Sal I and Bam HI were tested in CHO cells for their aberration-inducing effects. It was demonstrated that all these REs significantly increased the frequencies of aberrant cells, the aberration frequencies per cell and the aberration frequencies per chromosome. The effects of REs on chromosomal aberrations are similar to ionizing radiation, but more minutes and interchange figures are observed. Polyploid cells are more susceptible to RE treatment, an interesting finding which may be explained by the mechanisms leading to the formation of polyploid cells.

  1. Clean Air Slots Amid Atmospheric Pollution

    NASA Technical Reports Server (NTRS)

    Hobbs, Peter V.

    2002-01-01

    Layering in the Earth's atmosphere is most commonly seen where parts of the atmosphere resist the incursion of air parcels from above and below - for example, when there is an increase in temperature with height over a particular altitude range. Pollutants tend to accumulate underneath the resulting stable layers. which is why visibility often increases markedly above certain altitudes. Here we describe the occurrence of an opposite effect, in which stable layers generate a layer of remarkably clean air (we refer to these layers as clean-air 'slots') sandwiched between layers of polluted air. We have observed clean-air slots in various locations around the world, but they are particularly well defined and prevalent in southern Africa during the dry season August-September). This is because at this time in this region, stable layers are common and pollution from biomass burning is widespread.

  2. Size distributions of boundary-layer clouds

    SciTech Connect

    Stull, R.; Berg, L.; Modzelewski, H.

    1996-04-01

    Scattered fair-weather clouds are triggered by thermals rising from the surface layer. Not all surface layer air is buoyant enough to rise. Also, each thermal has different humidities and temperatures, resulting in interthermal variability of their lifting condensation levels (LCL). For each air parcel in the surface layer, it`s virtual potential temperature and it`s LCL height can be computed.

  3. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  4. Clean Air Slots Amid Atmospheric Pollution

    NASA Technical Reports Server (NTRS)

    Hobbs, Peter V.

    2002-01-01

    This article investigates the mechanism for those layers in the atmosphere that are free of air borne pollution even though the air above and below them carry pollutants. Atmospheric subsidence is posed as a mechanism for this phenomenon.

  5. The multiple layer solar collector

    NASA Astrophysics Data System (ADS)

    Kenna, J. P.

    1983-01-01

    An analytical model is developed for obtaining numerical solutions for differential equations describing the performance of separate layers in a multiple layer solar collector. The configurations comprises heat transfer fluid entering at the top of the collector and travelling down through several layers. A black absorber plate prevents reemission of thermal radiation. The overall performance is shown to depend on the number of layers, the heat transfer coefficient across each layer, and the absorption properties of the working fluid. It is found that the multiple layer system has a performance inferior to that of flat plate selective surface collectors. Air gaps insulating adjacent layers do not raise the efficiency enough to overcome the relative deficiency.

  6. Integration of air separation membrane and coalescing filter for use on an inlet air system of an engine

    DOEpatents

    Moncelle, Michael E.

    2003-01-01

    An intake air separation system suitable for combustion air of an internal combustion engine. An air separation device of the system includes a plurality of fibers, each fiber having a tube with a permeation barrier layer on the outer surface thereof and a coalescing layer on the inner surface thereof, to restrict fluid droplets from contacting the permeation barrier layer.

  7. Nonmixing layers

    NASA Astrophysics Data System (ADS)

    Gaillard, Pierre; Giovangigli, Vincent; Matuszewski, Lionel

    2016-12-01

    We investigate the impact of nonideal diffusion on the structure of supercritical cryogenic binary mixing layers. This situation is typical of liquid fuel injection in high-pressure rocket engines. Nonideal diffusion has a dramatic impact in the neighborhood of chemical thermodynamic stability limits where the components become quasi-immiscible and ultimately form a nonmixing layer. Numerical simulations are performed for mixing layers of H2 and N2 at a pressure of 100 atm and temperature around 120-150 K near chemical thermodynamic stability limits.

  8. Spallanzani Layers

    NASA Technical Reports Server (NTRS)

    2006-01-01

    31 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a layered, light-toned mesa among other layered materials exposed in a mound that covers much of the floor of Spallanzani Crater.

    Location near: 58.3oS, 273.9oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  9. Thin cylindrical sheets of air

    NASA Astrophysics Data System (ADS)

    Thoroddsen, Sigurdur; Beilharz, Daniel; Guyon, Axel; Li, Er Qiang; Thoraval, Marie-Jean

    2014-11-01

    Drops impacting at low velocities onto a pool surface can stretch out thin hemispheric sheets of air. These air sheets can remain intact until they reach submicron thicknesses, whereby they rupture to form myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In this way we are able to maintain stable air-layers which can wrap around the entire drop to form anti-bubbles, i.e. spherical air layers bounded by inner and outer liquid masses. Furthermore, for the most viscous drops they enter the pool trailing a viscous thread from the pinch-off from the nozzle. The air sheet can also wrap around these treads and remain stable over extended time to form a cylindrical air sheet. We study the parameter regime where these structures appear and their subsequent breakup. The stability of these air cylinders is inconsistent with inviscid stability theory, suggesting stabilization by lubrication forces within the submicron air layer.

  10. A Review and Evaluation of Integrated Atmospheric Boundary-Layer Models for Maritime Applications.

    DTIC Science & Technology

    1981-11-01

    cells . The large bouyant and turbulent mixing processes in the cloud tend to destroy the adiabatic (equilibrium) liquid water profile. Rather than...entraining upper layer air into the mixed layer, the convective cells draw air out of the mixed layer into the cell (and, therefore, the upper air) causing...01731 17. Dr. Hans Panovsky Department of Meteorology Penn State University State College, Pennslyvania 18. CDR K. Van Sickle Code Air-370 Naval Air

  11. Boundary-Layer & health

    NASA Astrophysics Data System (ADS)

    Costigliola, V.

    2010-09-01

    It has long been known that specific atmospheric processes, such as weather and longer-term climatic fluctuations, affect human health. The biometeorological literature refers to this relationship as meteorotropism, defined as a change in an organism that is correlated with a change in atmospheric conditions. Plenty of (patho)physiological functions are affected by those conditions - like the respiratory diseases - and currently it is difficult to put any limits for pathologies developed in reply. Nowadays the importance of atmospheric boundary layer and health is increasingly recognised. A number of epidemiologic studies have reported associations between ambient concentrations of air pollution, specifically particulate pollution, and adverse health effects, even at the relatively low concentrations of pollution found. Since 1995 there have been over twenty-one studies from four continents that have explicitly examined the association between ambient air pollutant mixes and daily mortality. Statistically significant and positive associations have been reported in data from various locations around the world, all with varying air pollutant concentrations, weather conditions, population characteristics and public health policies. Particular role has been given to atmospheric boundary layer processes, the impact of which for specific patient-cohort is, however, not well understood till now. Assessing and monitoring air quality are thus fundamental to improve Europe's welfare. One of current projects run by the "European Medical Association" - PASODOBLE will develop and demonstrate user-driven downstream information services for the regional and local air quality sectors by combining space-based and in-situ data with models in 4 thematic service lines: - Health community support for hospitals, pharmacies, doctors and people at risk - Public information for regions, cities, tourist industry and sporting event organizers - Compliance monitoring support on particulate

  12. Clean Air Act Requirements and History

    EPA Pesticide Factsheets

    In 1970 congress designed the Clean Air Act to combat a variety of air pollution problems, and to tackle emerging pollution threats such as public health, national welfare, toxic air pollutants, acid rain, protection of the ozone layer, and regional haze.

  13. Microgravity Effects on Plant Boundary Layers

    NASA Technical Reports Server (NTRS)

    Stutte, Gary; Monje, Oscar

    2005-01-01

    The goal of these series of experiment was to determine the effects of microgravity conditions on the developmental boundary layers in roots and leaves and to determine the effects of air flow on boundary layer development. It is hypothesized that microgravity induces larger boundary layers around plant organs because of the absence of buoyancy-driven convection. These larger boundary layers may affect normal metabolic function because they may reduce the fluxes of heat and metabolically active gases (e.g., oxygen, water vapor, and carbon dioxide. These experiments are to test whether there is a change in boundary layer associated with microgravity, quantify the change if it exists, and determine influence of air velocity on boundary layer thickness under different gravity conditions.

  14. Microgravity Effects on Plant Boundary Layers

    NASA Astrophysics Data System (ADS)

    Stutte, Gary; Monje, Oscar

    2005-08-01

    The goal of these series of experiment was to determine the effects of microgravity conditions on the developmental boundary layers in roots and leaves and to determine the effects of air flow on boundary layer development. It is hypothesized that microgravity induces larger boundary layers around plant organs because of the absence of buoyancy-driven convection. These larger boundary layers may affect normal metabolic function because they may reduce the fluxes of heat and metabolically active gases (e.g., oxygen, water vapor, and carbon dioxide. These experiments are to test whether there is a change in boundary layer associated with microgravity, quantify the change if it exists, and determine influence of air velocity on boundary layer thickness under different gravity conditions.

  15. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

  16. Air Pollution

    MedlinePlus

    ... of Climate Change on Children's Health: Session Two: Air Quality Impacts MODERATOR: Susan Anenberg, EPA Meredith McCormack, Johns ... University • Effects of Climate Change on Children’s Health: Air Quality Impacts Frederica Perera, Columbia University • Air quality Impacts ...

  17. The atmospheric boundary layer

    SciTech Connect

    Garratt, J.R.

    1992-01-01

    This book is aimed at researchers in the atmospheric and associated sciences who require a moderately advanced text on the Atmospheric Boundary Layer (ABL) in which the many links between turbulence, air-surface transfer, boundary-layer structure and dynamics, and numerical modeling are discussed and elaborated upon. Chapter 1 serves as an introduction, with Chapters 2 and 3 dealing with the development of mean and turbulence equations, and the many scaling laws and theories that are the cornerstone of any serious ABL treatment. Modelling of the ABL is crucially dependent for its realism on the surface boundary conditions, and Chapters 4 and 5 deal with aerodynamic and energy considerations, with attention to both dry and wet land surfaces and the sea. The structure of the clear-sky, thermally stratified ABL is treated in Chapter 6, including the convective and stable cases over homogeneous land, the marine ABL and the internal boundary layer at the coastline. Chapter 7 then extends the discussion to the cloudy ABL. This is seen as particularly relevant since the extensive stratocumulus regions over the sub-tropical oceans and stratus regions over the Arctic are now identified as key players in the climate system. Finally, Chapters 8 and 9 bring much of the book's material together in a discussion of appropriate ABL and surface parameterization schemes for the general circulation models of the atmosphere that are being used for climate simulation.

  18. An improved bifunctional oxygen (air) electrode for reversible alkaline fuel cell systems and for rechargeable metal-air batteries

    NASA Astrophysics Data System (ADS)

    Kordesch, K.; Steininger, K.-H.; Tomantschger, K.

    1988-10-01

    Electrodes with a nickel layer of dual pore structure on the electrolyte side and a PTFE-bonded carbon layer on the oxygen (air) side are discussed, with application to space energy storage. During the electrolyis stage, the oxygen fills the large pores of the porous Ni structure with gas. During the discharge cycle, the iron/air or zinc/air cell of the carbon layer operates as a regular oxygen electrode.

  19. The Lowest Atmosphere: Atmospheric Boundary Layer Including Atmospheric Surface Layer.

    DTIC Science & Technology

    1996-04-01

    troposphere" as a result of frictional forces. A good definition of the atmospheric boundary layer (ABL) (provided to me by the late Dr. Rudy...wind extends light flag. Raises dust and loose paper; small branches are moved. Small trees in leaf begin to sway; crested wavelets form on inland...Calm. Sea like a mirror. Light air Ripples like scales, no foam crest. Light breeze Small wavelets ; crests have glassy appearance, do not break

  20. Sound transmission through a poroelastic layered panel

    NASA Astrophysics Data System (ADS)

    Nagler, Loris; Rong, Ping; Schanz, Martin; von Estorff, Otto

    2014-04-01

    Multi-layered panels are often used to improve the acoustics in cars, airplanes, rooms, etc. For such an application these panels include porous and/or fibrous layers. The proposed numerical method is an approach to simulate the acoustical behavior of such multi-layered panels. The model assumes plate-like structures and, hence, combines plate theories for the different layers. The poroelastic layer is modelled with a recently developed plate theory. This theory uses a series expansion in thickness direction with subsequent analytical integration in this direction to reduce the three dimensions to two. The same idea is used to model either air gaps or fibrous layers. The latter are modeled as equivalent fluid and can be handled like an air gap, i.e., a kind of `air plate' is used. The coupling of the layers is done by using the series expansion to express the continuity conditions on the surfaces of the plates. The final system is solved with finite elements, where domain decomposition techniques in combination with preconditioned iterative solvers are applied to solve the final system of equations. In a large frequency range, the comparison with measurements shows very good agreement. From the numerical solution process it can be concluded that different preconditioners for the different layers are necessary. A reuse of the Krylov subspace of the iterative solvers pays if several excitations have to be computed but not that much in the loop over the frequencies.

  1. Double Layers in Astrophysics

    NASA Technical Reports Server (NTRS)

    Williams, Alton C. (Editor); Moorehead, Tauna W. (Editor)

    1987-01-01

    Topics addressed include: laboratory double layers; ion-acoustic double layers; pumping potential wells; ion phase-space vortices; weak double layers; electric fields and double layers in plasmas; auroral double layers; double layer formation in a plasma; beamed emission from gamma-ray burst source; double layers and extragalactic jets; and electric potential between plasma sheet clouds.

  2. Air Policing

    DTIC Science & Technology

    2009-05-01

    Iraq. To provide a background for understanding why Britain commenced the policy of air policing, this paper begins with a review of contemporary...7 Omissi, Air Power, XV. 8 policing actions or the pushing home of advantages gained by the air.” Within the context of this paper , the...control operations, and therefore within the context of this paper , the term coercive airpower refers to the threat of harming a population or the threat

  3. Ozone Layer Protection

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Ozone Layer Protection Share Facebook Twitter Google+ Pinterest Contact Us Ozone Layer Protection Welcome to EPA's ozone layer protection web ...

  4. Mobilization of arsenic and other trace elements of health concern in groundwater from the Salí River Basin, Tucumán Province, Argentina.

    PubMed

    Nicolli, Hugo B; García, Jorge W; Falcón, Carlos M; Smedley, Pauline L

    2012-04-01

    The Salí River Basin in north-west Argentina (7,000 km(2)) is composed of a sequence of Tertiary and Quaternary loess deposits, which have been substantially reworked by fluvial and aeolian processes. As with other areas of the Chaco-Pampean Plain, groundwater in the basin suffers a range of chemical quality problems, including arsenic (concentrations in the range of 12.2-1,660 μg L(-1)), fluoride (50-8,740 μg L(-1)), boron (34.0-9,550 μg L(-1)), vanadium (30.7-300 μg L(-1)) and uranium (0.03-125 μg L(-1)). Shallow groundwater (depths up to 15 m) has particularly high concentrations of these elements. Exceedances above WHO (2011) guideline values are 100% for As, 35% for B, 21% for U and 17% for F. Concentrations in deep (>200 m) and artesian groundwater in the basin are also often high, though less extreme than at shallow depths. The waters are oxidizing, with often high bicarbonate concentrations (50.0-1,260 mg L(-1)) and pH (6.28-9.24). The ultimate sources of these trace elements are the volcanic components of the loess deposits, although sorption reactions involving secondary Al and Fe oxides also regulate the distribution and mobility of trace elements in the aquifers. In addition, concentrations of chromium lie in range of 79.4-232 μg L(-1) in shallow groundwater, 129-250 μg L(-1) in deep groundwater and 110-218 μg L(-1) in artesian groundwater. All exceed the WHO guideline value of 50 μg L(-1). Their origin is likely to be predominantly geogenic, present as chromate in the ambient oxic and alkaline aquifer conditions.

  5. Air transport

    NASA Technical Reports Server (NTRS)

    Page, F Handley

    1924-01-01

    I purpose (sic) in this paper to deal with the development in air transport which has taken place since civil aviation between England and the Continent first started at the end of August 1919. A great deal of attention has been paid in the press to air services of the future, to the detriment of the consideration of results obtained up to the present.

  6. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  7. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  8. An Experiment to Study Sporadic Sodium Layers in the Earth's Mesosphere and Lower Thermosphere

    NASA Technical Reports Server (NTRS)

    Swenson, Charles M.

    2002-01-01

    The Utah State University / Space Dynamics Lab was funded under a NASA Grant. This investigation has been part of Rockwell Universities Sudden Atom Layer Investigation (SAL). USU/SDL provided an electron density measurement instrument, the plasma frequency probe, which was launched on the vehicle 21.117 from Puerto-Rico in February of 1998. The instrument successfully measured electron density as designed and measurement techniques included in this version of the Plasma Frequency probe provided valuable insight into the electron density structures associated with sudden sodium layers in a collisional plasma. Electron density data was furnished to Rockwell University but no science meetings were held by Rockwell Data from the instrument was presented to the scientific community at the URSI General Session in 1999. A paper is in preparation for publication in Geophysical Research Letters. The following document provides a summary of the experiment and data obtained as a final report on this grant.

  9. Core layering

    NASA Astrophysics Data System (ADS)

    Jacobson, S. A.; Rubie, D. C.; Hernlund, J. W.; Morbidelli, A.

    2015-12-01

    We have created a planetary accretion and differentiation model that self-consistently builds and evolves Earth's core. From this model, we show that the core grows stably stratified as the result of rising metal-silicate equilibration temperatures and pressures, which increases the concentrations of light element impurities into each newer core addition. This stable stratification would naturally resist convection and frustrate the onset of a geodynamo, however, late giant impacts could mechanically mix the distinct accreted core layers creating large homogenous regions. Within these regions, a geodynamo may operate. From this model, we interpret the difference between the planetary magnetic fields of Earth and Venus as a difference in giant impact histories. Our planetary accretion model is a numerical N-body integration of the Grand Tack scenario [1]—the most successful terrestrial planet formation model to date [2,3]. Then, we take the accretion histories of Earth-like and Venus-like planets from this model and post-process the growth of each terrestrial planet according to a well-tested planetary differentiation model [4,5]. This model fits Earth's mantle by modifying the oxygen content of the pre-cursor planetesimals and embryos as well as the conditions of metal-silicate equilibration. Other non-volatile major, minor and trace elements included in the model are assumed to be in CI chondrite proportions. The results from this model across many simulated terrestrial planet growth histories are robust. If the kinetic energy delivered by larger impacts is neglected, the core of each planet grows with a strong stable stratification that would significantly impede convection. However, if giant impact mixing is very efficient or if the impact history delivers large impacts late, than the stable stratification can be removed. [1] Walsh et al. Nature 475 (2011) [2] O'Brien et al. Icarus 223 (2014) [3] Jacobson & Morbidelli PTRSA 372 (2014) [4] Rubie et al. EPSL 301

  10. LDV measurements of turbulent baroclinic boundary layers

    SciTech Connect

    Neuwald, P.; Reichenbach, H.; Kuhl, A.L.

    1993-07-01

    Described here are shock tube experiments of nonsteady, turbulent boundary layers with large density variations. A dense-gas layer was created by injecting Freon through the porous floor of the shock tube. As the shock front propagated along the layer, vorticity was created at the air-Freon interface by an inviscid, baroclinic mechanism. Shadow-schlieren photography was used to visualize the turbulent mixing in this baroclinic boundary layer. Laser-Doppler-Velocimetry (LDV) was used to measure the streamwise velocity histories at 14 heights. After transition, the boundary layer profiles may be approximated by a power-law function u {approximately} u{sup {alpha}} where {alpha} {approx_equal} 3/8. This value lies between the clean flat plate value ({alpha} = 1/7) and the dusty boundary layer value ({alpha} {approx_equal} 0.7), and is controlled by the gas density near the wall.

  11. The Rechargeability of Silicon-Air Batteries

    DTIC Science & Technology

    2012-06-01

    seconds in order to remove surface native oxide layer. The silicon was then rinsed with de- ionized (DI) water and dried using a nitrogen stream. After the...continued operation without loss of energy density, and avoiding the build-up of water byproduct in the electrolyte during reduction during recharge phase...an Si-air electrochemical cell a source of water for other applications. Metal-air batteries, silicon-air, electrochemistry, rechargeable batteries UU

  12. Air Apparent.

    ERIC Educational Resources Information Center

    Harbster, David A.

    1988-01-01

    Explains the principle upon which a barometer operates. Describes how to construct two barometric devices for use in the classroom that show air's changing pressure. Cites some conditions for predicting weather. (RT)

  13. Air Abrasion

    MedlinePlus

    ... information you need from the Academy of General Dentistry Sunday, April 9, 2017 About | Contact InfoBites Quick ... general dentist, who has been trained in restorative dentistry techniques, will perform any procedures that use air- ...

  14. The Periplasmic Chaperone Network of Campylobacter jejuni: Evidence that SalC (Cj1289) and PpiD (Cj0694) Are Involved in Maintaining Outer Membrane Integrity

    PubMed Central

    Taylor, Aidan J.; Zakai, Shadi A. I.; Kelly, David J.

    2017-01-01

    holdase-type chaperone activity. Cj0694 is most similar to the PpiD class of chaperones but is unusual in possessing PPIase activity. Taken together, our data show that in addition to PEB4, Cj1289 (SalC; SurA-like chaperone) and Cj0694 (PpiD) are also key proteins involved in OM biogenesis and integrity in C. jejuni.

  15. Characterization of salA, syrF, and syrG Genes and Attendant Regulatory Networks Involved in Plant Pathogenesis by Pseudomonas syringae pv. syringae B728a

    PubMed Central

    Vaughn, Vanessa L.; Gross, Dennis C.

    2016-01-01

    Pseudomonas syringae pv. syringae B728a, causal agent of brown spot on bean, is an economically important plant pathogen that utilizes extracellular signaling to initiate a lifestyle change from an epiphyte to a pathogen. LuxR regulatory proteins play an important role in the transcriptional regulation of a variety of biological processes involving two-component signaling, quorum sensing, and secondary metabolism. Analysis of the B728a genome identified 24 LuxR-like proteins, three of which are encoded by salA, syrF, and syrG located adjacent to the syringomycin gene cluster. The LuxR-like proteins encoded by these three genes exhibit a domain architecture that places them in a subfamily of LuxR-like proteins associated with regulation of secondary metabolism in B728a. Deletion mutants of salA, syrF, and syrG failed to produce syringomycin and displayed reduction of virulence on bean. The transcriptional start sites of salA, syrG, and syrF were located 63, 235, and 498 bp upstream of the start codons, respectively, using primer extension analysis. The predicted -10/-35 promoter regions of syrF and syrG were confirmed using site-directed mutagenesis and GFP reporters that showed conserved promoter sequences around the -35 promoter region. Overexpression analysis and GFP reporters identified SyrG as an upstream transcriptional activator of syrF, where both SyrG and SyrF activate promoters of syringomycin biosynthesis genes. This study shows that syrG and syrF encode important transcriptional regulators of syringomycin biosynthesis genes. PMID:26954255

  16. Laminar boundary layer in conditions of natural transition to turbulent flow

    NASA Technical Reports Server (NTRS)

    Polyakov, N. F.

    1986-01-01

    Results of experimental study of regularities of a natural transition of a laminar boundary layer to a turbulent layer at low subsonic air flow velocities are presented, analyzed and compared with theory and model experiments.

  17. Hazardous Air Pollutants

    MedlinePlus

    ... Air Toxics Website Rules and Implementation Related Information Air Quality Data and Tools Clean Air Act Criteria Air ... Resources Visibility and Haze Voluntary Programs for Improving Air Quality Contact Us to ask a question, provide feedback, ...

  18. Air surveillance

    SciTech Connect

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  19. Environmental Instability and Degradation of Single- and Few-Layer WTe2 Nanosheets in Ambient Conditions.

    PubMed

    Ye, Fan; Lee, Jaesung; Hu, Jin; Mao, Zhiqiang; Wei, Jiang; Feng, Philip X-L

    2016-09-08

    Ambient environmental instability and degradation mechanism of single- and few-layer WTe2 are investigated. Oxidation of W and Te atoms appears to be a main reason for degradation. Single-layer samples' Raman signals disappear within 20 min in air. Few-layer WTe2 exhibits saturating degradation behavior: only the top layer WTe2 is oxidized; the degraded layer can protect inner layers from further degradation.

  20. Shear layer excitation, experiment versus theory

    NASA Technical Reports Server (NTRS)

    Bechert, D. W.; Stahl, B.

    1984-01-01

    The acoustical excitation of shear layers is investigated. Acoustical excitation causes the so-called orderly structures in shear layers and jets. Also, the deviations in the spreading rate between different shear layer experiments are due to the same excitation mechanism. Measurements in the linear interaction region close to the edge from which the shear layer is shed are examined. Two sets of experiments (Houston 1981 and Berlin 1983/84) are discussed. The measurements were carried out with shear layers in air using hot wire anemometers and microphones. The agreement between these measurements and the theory is good. Even details of the fluctuating flow field correspond to theoretical predictions, such as the local occurrence of negative phase speeds.

  1. New Approach to Depositing Yttria-Stabilized Zirconia Buffer Layers for Coated Conductors (Postprint)

    DTIC Science & Technology

    2012-02-01

    distribution unlimited. See additional restrictions described on inside pages STINFO COPY © 2003 Materials Research Society AIR... additional layer in the buffer layer stack—a transient nickel layer deposited directly on the substrate. Regardless of the substrate and protective layers...Ridge Na- tional Laboratory ( ORNL ), Oak Ridge, TN, were precleaned in organic solvents (acetone, ethanol, chloro- form) using ultrasonic agitation

  2. Transport Processes in the Coastal Atmospheric Boundary Layer

    DTIC Science & Technology

    2016-06-07

    coastlines or boundary layer processes at the coast. The transported constituents may be properties of the marine boundary layer, e.g. humidity, air ... pollution or aerosols, the latter both of natural and man-made origin. In particular I am interested in the cross-coast mixing potential. By this I mean...speed maximas. Also some properties of the coastal marine air , e.g. the presence of aerosol and low clouds, are detrimental to remote sensing based on

  3. The Ocean Boundary Layer beneath Hurricane Frances

    NASA Astrophysics Data System (ADS)

    Dasaro, E. A.; Sanford, T. B.; Terrill, E.; Price, J.

    2006-12-01

    The upper ocean beneath the peak winds of Hurricane Frances (57 m/s) was measured using several varieties of air-deployed floats as part of CBLAST. A multilayer structure was observed as the boundary layer deepened from 20m to 120m in about 12 hours. Bubbles generated by breaking waves create a 10m thick surface layer with a density anomaly, due to the bubbles, of about 1 kg/m3. This acts to lubricate the near surface layer. A turbulent boundary layer extends beneath this to about 40 m depth. This is characterized by large turbulent eddies spanning the boundary layer. A stratified boundary layer grows beneath this reaching 120m depth. This is characterized by a gradient Richardson number of 1/4, which is maintained by strong inertial currents generated by the hurricane, and smaller turbulent eddies driven by the shear instead of the wind and waves. There is little evidence of mixing beneath this layer. Heat budgets reveal the boundary layer to be nearly one dimensional through much of the deepening, with horizontal and vertical heat advection becoming important only after the storm had passed. Turbulent kinetic energy measurements support the idea of reduced surface drag at high wind speeds. The PWP model correctly predicts the degree of mixed layer deepening if the surface drag is reduced at high wind speed. Overall, the greatest uncertainty in understanding the ocean boundary layer at these extreme wind speeds is a characterization of the near- surface processes which govern the air-sea fluxes and surface wave properties.

  4. Behavior of cationic surfactants and short-chain alcohols in mixed surface layers at water-air and polymer-water interfaces with regard to polymer wettability II. Wettability of polymers.

    PubMed

    Zdziennicka, Anna; Jańczuk, Bronisław

    2010-10-15

    The wettability of polytetrafluoroethylene (PTFE) and polymethylmethacrylate (PMMA) by aqueous solutions of cetyltrimethylammonium bromide (CTAB) mixtures with short-chain alcohols such as methanol, ethanol, and propanol, as well as for 1-hexadecylpyridinium bromide (CPyB) with the same alcohols, was studied on the basis of advancing contact-angle measurements by the sessile drop method over a wide range of alcohol and cationic surfactant concentrations where they can be present in solution in monomeric or aggregated form. It should be noted that the contact angles for aqueous solution mixtures of cationic surfactants with propanol on PTFE surfaces were measured earlier and presented in our previous paper. From the obtained contact-angle values the relationships between cos theta and surface tension of the solutions (gamma(LV)) and that between adhesion tension and gamma(LV) were considered. The relationship between the cos theta and the reciprocal of gamma(LV) was also discussed. From these relationships the critical surface tension of PTFE and PMMA wetting and the correlation between the adsorption of cationic surfactant and alcohol mixtures at water-air and polymer-water interfaces were deduced. On the basis of the contact angles and components and parameters of the surface tension of surfactants, alcohols, and polymers also the Gibbs and Guggenheim-Adam isotherm of adsorption and the effective concentration of alcohols and surfactants at polymer-water interfaces were calculated. Next, the work of adhesion of solution to polymer surface with regard to the surface monolayer composition was discussed. The analysis of the contact angles with regard to adsorption of surfactants and alcohols at polymer-water and water-air interfaces allowed us to conclude that the PTFE wetting depends only on the contribution of the acid-base interactions to the surface tension of aqueous solutions of cationic surfactant and alcohol mixtures, and the adhesion work of solution to its

  5. Air Pollution.

    ERIC Educational Resources Information Center

    Scorer, Richard S.

    The purpose of this book is to describe the basic mechanisms whereby pollution is transported and diffused in the atmosphere. It is designed to give practitioners an understanding of basic mechanics and physics so they may have a correct basis on which to formulate their decisions related to practical air pollution control problems. Since many…

  6. A double-blind crossover study comparing the safety and efficacy of three weeks of Flu/Sal 250/50 bid plus albuterol 180 ug prn q4 hours to Flu/Sal 250/50 bid plus albuterol/Ipratropium bromide 2 puffs prn q4 hours in patients with chronic obstructive pulmonary disease.

    PubMed

    Balkissoon, Ron; Make, Barry

    2008-08-01

    The Federal Drug Administration (FDA) approved the use of Fluticasone 250 microg/Salmeterol 50 microg 1 puff bid for maintenance therapy in patients with COPD associated with chronic bronchitis. Short-acting beta agonists (SABA) have been the recommended rescue medication; however, previous studies have shown that combination short-acting Albuterol (alb) /Ipratropium bromide (IB) has superior bronchodilator properties to albuterol alone in patients with COPD. The safety and efficacy of Albuterol compared to Albuterol/Ipratropium bromide as rescue medications for COPD patients on maintenance combination therapy of ICS/LABA has not been evaluated. Double-blind randomized crossover trial with COPD subjects receiving Fluticasone/ Salmeterol 500 microg/50 microg (Flu/Sal) 1 puff twice daily and 2 puffs of Albuterol Sulfate (90 microg micrograms per inhalation) or 2 puffs of Albuterol (90 microg/puff and Ipratropium Bromide 18 microg/puff. Either Albuterol Sulfate (90 micrograms/puff) or Alb (90 micrograms/puff)/IB used prn for 3 weeks before crossing over to the other rescue formulation. This is a non-inferiority study where safety and efficacy outcomes were serially assessed, including adverse events, Baseline (BDI)/Transition Dyspnea Index (TDI), St. George Respiratory Questionnaire (SGRQ), SF36, diary cards, 24-hour cardiac monitoring, potassium and glucose levels and other adverse events. Twenty subjects completed the study. The mean age was 62.5 (+/- 14.5); 12 were males. The mean baseline FEV(1) (range) was 1.12 L (0.56-1.67) or 40.6 (21-65)% predicted. There were no statistically significant differences between either rescue inhaler formulation with regard to measures neither of lung function or dyspnea nor in terms of safety parameters of cardiac monitoring, glucose and potassium levels and other adverse events. SABA and combination SABA/Ipratropium bromide are equally safe and efficacious as rescue inhalers for patients on combination Fluticasone 500 microg

  7. Air transparent soundproof window

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Hoon; Lee, Seong-Hyun

    2014-11-01

    A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories: the theory of diffraction and the theory of acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered on each individual resonator. The negative effective bulk modulus of the resonators produces evanescent wave, and at the same time the air holes with subwavelength diameter existed on the surfaces of the window for macroscopic air ventilation. The acoustic performance levels of two soundproof windows with air holes of 20mm and 50mm diameters were measured. The sound level was reduced by about 30 - 35dB in the frequency range of 400 - 5,000Hz with the 20mm window, and by about 20 - 35dB in the frequency range of 700 - 2,200Hz with the 50mm window. Multi stop-band was created by the multi-layers of the window. The attenuation length or the thickness of the window was limited by background noise. The effectiveness of the soundproof window with airflow was demonstrated by a real installation.

  8. Air transparent soundproof window

    SciTech Connect

    Kim, Sang-Hoon; Lee, Seong-Hyun

    2014-11-15

    A soundproof window or wall which is transparent to airflow is presented. The design is based on two wave theories: the theory of diffraction and the theory of acoustic metamaterials. It consists of a three-dimensional array of strong diffraction-type resonators with many holes centered on each individual resonator. The negative effective bulk modulus of the resonators produces evanescent wave, and at the same time the air holes with subwavelength diameter existed on the surfaces of the window for macroscopic air ventilation. The acoustic performance levels of two soundproof windows with air holes of 20mm and 50mm diameters were measured. The sound level was reduced by about 30 - 35dB in the frequency range of 400 - 5,000Hz with the 20mm window, and by about 20 - 35dB in the frequency range of 700 - 2,200Hz with the 50mm window. Multi stop-band was created by the multi-layers of the window. The attenuation length or the thickness of the window was limited by background noise. The effectiveness of the soundproof window with airflow was demonstrated by a real installation.

  9. Analyzing the effect of the forces exerted on cantilever probe tip of atomic force microscope with tapering-shaped geometry and double piezoelectric extended layers in the air and liquid environments

    NASA Astrophysics Data System (ADS)

    Korayem, Moharam Habibnejad; Nahavandi, Amir

    2017-01-01

    The aim of the present study is to assess the force vibrational performance of tapering-shaped cantilevers, using Euler-Bernoulli theory. Tapering-shaped cantilevers have plan-view geometry consisting of a rectangular section at the clamped end and a triangular section at the tip. Hamilton's principle is utilized to obtain the partial differential equations governing the nonlinear vibration of the system as well as the corresponding boundary conditions. In this model, a micro cantilever, which is covered by two piezoelectric layers at the top and the bottom, is modeled at angle α. Both of these layers are subjected to similar AC and DC voltages. This paper attempts to determine the effect of the capillary force exerted on the cantilever probe tip of an atomic force microscope. The capillary force emerges due to the contact between thin water films with a thickness of hc which have accumulated on the sample and the probe. In addition, an attempt is made to develop the capillary force between the tip and the sample surface with respect to the geometry obtained. The smoothness or the roughness of the surfaces as well as the geometry of the cantilever tip have significant effects on the modeling of forces applied to the probe tip. In this article, the Van der Waals and the repulsive forces are considered to be the same in all of the simulations, and only is the capillary force altered in order to evaluate the role of this force in the atomic force microscope based modeling. We also indicate that the tip shape and the radial distance of the meniscus greatly influence the capillary force. The other objective of our study is to draw a comparison between tapering-and rectangular-shaped cantilevers. Furthermore, the equation for converting the tip of a tapering-shaped cantilever into a rectangular cantilever is provided. Moreover, the modal analysis method is employed to solve the motion equation. The mode shape function for the two tapering-shaped sections of the first

  10. Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength.

    PubMed

    Bijelic-Donova, Jasmina; Garoushi, Sufyan; Lassila, Lippo V J; Vallittu, Pekka K

    2015-02-01

    An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short-fiber-reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated. Four different restorative composites were selected: everX Posterior (a short-fiber-reinforced composite), Z250, SupremeXT, and Silorane. All composites were evaluated regarding the thickness of the oxygen inhibition layer and for shear bond strength. An equal amount of each composite was polymerized in air between two glass plates and the thickness of the oxygen inhibition layer was measured using a stereomicroscope. Cylindrical-shaped specimens were prepared for measurement of shear bond strength by placing incrementally two layers of the same composite material. Before applying the second composite layer, the first increment's bonding site was treated as follows: grinding with 1,000-grit silicon-carbide (SiC) abrasive paper, or treatment with ethanol or with water-spray. The inhibition depth was lowest (11.6 μm) for water-sprayed Silorane and greatest (22.9 μm) for the water-sprayed short-fiber-reinforced composite. The shear bond strength ranged from 5.8 MPa (ground Silorane) to 36.4 MPa (water-sprayed SupremeXT). The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short-fiber-reinforced composite. Thus, more durable adhesion with short-fiber-reinforced composite is expected.

  11. Physical characteristics of the oceanic skin layer

    NASA Astrophysics Data System (ADS)

    Hanafin, J.; Minnett, P. J.

    2006-12-01

    On the liquid side of the ocean-atmosphere interface lies the oceanic skin layer. Its ubiquitous presence is a consequence of ocean-atmosphere heat flux, which in turn it regulates as the heat and gas fluxes through the skin layer are supported by molecular conduction, which is much less effective at vertical transport than turbulence in the fluids above and below. The skin layer also modulates air-sea exchanges of gases and momentum. While it displays complex structure on millimeters to meters, the skin layer can be represented on horizontal scales of meters and more in terms of mean properties. Accurate spectro-radiometric measurements of the skin temperature and its variation with depth on sub-millimeter scales have revealed a thinner mean skin than previously anticipated from laboratory measurements; ship-based measurements indicate a skin layer an order of magnitude thinner than those measured in an open-air laboratory using the same instruments, which at a thickness of O(1mm) agree with measurements in the literature. Examples of the skin layer behavior based on measurements at sea under a range of natural forcing (winds, net heat flux and net infrared radiative flux) will be presented.

  12. Demonstration of optical interference filters utilizing tunable refractive index layers.

    PubMed

    Poxson, David J; Mont, Frank W; Schubert, Martin F; Kim, Jong Kyu; Cho, Jaehee; Schubert, E Fred

    2010-11-08

    Optical interference filters utilizing tunable refractive index layers are shown to have higher spectral fidelity as compared to conventional filters consisting of non-tunable refractive index layers. To demonstrate this increase in spectral fidelity, we design and compare a variety of optical interference filters employing both tunable and non-tunable refractive index layers. Additionally, a five-layer optical interference filter utilizing tunable refractive index layers is designed and fabricated for use with a Xenon lamp to replicate the Air Mass 0 solar irradiance spectrum and is shown to have excellent spectral fidelity.

  13. Atmospheric aerosol layers over Bangkok Metropolitan Region from CALIPSO observations

    NASA Astrophysics Data System (ADS)

    Bridhikitti, Arika

    2013-06-01

    Previous studies suggested that aerosol optical depth (AOD) from the Earth Observing System satellite retrievals could be used for inference of ground-level air quality in various locations. This application may be appropriate if pollution in elevated atmospheric layers is insignificant. This study investigated the significance of elevated air pollution layers over the Bangkok Metropolitan Region (BMR) from all available aerosol layer scenes taken from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) for years 2007 to 2011. The results show that biomass burning smoke layers alone were the most frequently observed. The smoke layers accounted for high AOD variations and increased AOD levels. In the dry seasons, the smoke layers alone with high AOD levels were likely brought to the BMR via northeasterly to easterly prevailing winds and found at altitudes above the typical BMR mixing heights of approximately 0.7 to 1.5 km. The smoke should be attributed to biomass burning emissions outside the BMR.

  14. Air pollution.

    PubMed

    Le, Nhu D; Sun, Li; Zidek, James V

    2010-01-01

    Toxic air pollutants are continuously released into the air supply. Various pollutants come from chemical facilities and small businesses, such as automobile service stations and dry cleaning establishments. Others, such as nitrogen oxides, carbon monoxide and other volatile organic chemicals, arise primarily from the incomplete combustion of fossil fuels (coal and petroleum) and are emitted from sources that include car exhausts, home heating and industrial power plants. Pollutants in the atmosphere also result from photochemical transformations; for example, ozone is formed when molecular oxygen or nitrogen interacts with ultraviolet radiation. An association between air pollution exposure and lung cancer has been observed in several studies. The evidence for other cancers is far less conclusive. Estimates of the population attributable risk of cancer has varied substantially over the last 40 years, reflecting the limitations of studies; these include insufficient information on confounders, difficulties in characterizing associations due to a likely lengthy latency interval, and exposure misclassification. Although earlier estimates were less than one percent, recent cohort studies that have taken into account some confounding factors, such as smoking and education amongst others, suggest that approximately 3.6% of lung cancer in the European Union could be due to air pollution exposure, particularly to sulphate and fine particulates. A separate cohort study estimated 5-7% of lung cancers in European never smokers and ex-smokers could be due to air pollution exposure. Therefore, while cigarette smoking remains the predominant risk factor, the proportion of lung cancers attributable to air pollution may be higher than previously thought. Overall, major weaknesses in all air-pollution-and-cancer studies to date have been inadequate characterization of long-term air pollution exposure and imprecise or no measurements of covariates. It has only been in the last

  15. Airborne Sunphotometry of African Dust and Marine Boundary Layer Aerosols in PRIDE

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Redemann, Jens; Russell, Philip; Schmid, Beat; Reid, Jeff; Pilewskie, Peter; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    The Puerto Rico Dust Experiment (PRIDE) was conducted during summer 2000 to study the radiative, microphysical and transport properties of Saharan dust in the Caribbean region. During PRIDE, NASA Ames Research Center's six-channel airborne autotracking sunphotometer (AATS-6) was operated aboard a Piper Navajo airplane based at Roosevelt Roads Naval Station on the northeast coast of Puerto Rico. AATS-6 measurements were taken during 21 science flights off the coast of Puerto Rico in the western Caribbean. Data were acquired within and above the Marine Boundary Layer (MBL) and the Saharan Aerosol Layer (SAL) up to 5.5 km altitude tinder a wide range of dust loadings. Aerosol optical depth (AOD) spectra and columnar water vapor (CWV) values have been calculated from the AATS-6 measurements by using sunphotometer calibration data obtained at Mauna Loa Observatory (3A kin ASL) before (May) and after (October) PRIDE. Mid-visible AOD values measured near the surface during PRIDE ranged from 0.07 on the cleanest day to 0.55 on the most turbid day. Values measured above the MBL were as high as 0.35; values above the SAL were as low as 0.01. The fraction of total column AOD due to Saharan dust cannot be determined precisely from AATS-6 AOD data alone due to the uncertainty in the extent of vertical mixing of the dust down through the MBL. However, analyses of ground-based and airborne in-situ aerosol sampling measurements and ground-based aerosol lidar backscatter data should yield accurate characterization of the vertical mixing that will enable calculation of the Saharan dust AOD component from the sunphotometer data. Examples will be presented showing measured AATS-6 AOD spectra, calculated aerosol extinction and water vapor density vertical profiles, and aerosol size distributions retrieved by inversion of the AOD spectra. Near sea-surface AOD spectra acquired by AATS-6 during horizontal flight legs at 30 m ASL are available for validation of AOD derived from coincident

  16. Acoustic radar investigations of boundary layer phenomena

    NASA Technical Reports Server (NTRS)

    Marks, J. R.

    1974-01-01

    A comparison is made between acoustic radar echoes and conventional meteorological data obtained from the WKY tower, for the purpose of better understanding the relationships between acoustic radar echoes and boundary layer processes. Two thunderstorm outflow cases are presented and compared to both acoustic radar data and Charba's gust front model. The acoustic radar echoes reveal the boundary between warm and cold air and other areas of mixing and strong thermal gradient quite well. The thunderstorm outflow of 27 June 1972 is found to compare with in most respects to Charba's gust front model. The major difference is the complete separation of the head from the main body of cold air, probably caused by erosion of the area behind the head by mixing with the ambient air. Two cases of nocturnal inversions caused by advection of warmer air aloft are presented. It is found that areas of turbulent mixing or strong thermal gradient can be identified quite easily in the acoustic radar record.

  17. Reassembly of S-layer proteins

    NASA Astrophysics Data System (ADS)

    Pum, Dietmar; Sleytr, Uwe B.

    2014-08-01

    Crystalline bacterial cell surface layers (S-layers) represent the outermost cell envelope component in a broad range of bacteria and archaea. They are monomolecular arrays composed of a single protein or glycoprotein species and represent the simplest biological membranes developed during evolution. They are highly porous protein mesh works with unit cell sizes in the range of 3 to 30 nm, and pore sizes of 2 to 8 nm. S-layers are usually 5 to 20 nm thick (in archaea, up to 70 nm). S-layer proteins are one of the most abundant biopolymers on earth. One of their key features, and the focus of this review, is the intrinsic capability of isolated native and recombinant S-layer proteins to form self-assembled mono- or double layers in suspension, at solid supports, the air-water interface, planar lipid films, liposomes, nanocapsules, and nanoparticles. The reassembly is entropy-driven and a fascinating example of matrix assembly following a multistage, non-classical pathway in which the process of S-layer protein folding is directly linked with assembly into extended clusters. Moreover, basic research on the structure, synthesis, genetics, assembly, and function of S-layer proteins laid the foundation for their application in novel approaches in biotechnology, biomimetics, synthetic biology, and nanotechnology.

  18. A numerical investigation of boundary layer quasi-equilibrium

    NASA Astrophysics Data System (ADS)

    Thayer-Calder, K.; Randall, David

    2015-01-01

    Despite the large energy input from surface evaporation, the moist static energy (MSE) of the tropical boundary layer remains relatively constant on large spatial and temporal scales due to lifting of vapor by cloudy updrafts and the addition of dry air from the layers above. Arakawa and Schubert (1974) suggested that drying is due mainly to clear-air turbulent entrainment between cloudy updrafts, while Raymond (1995) described drying due mainly to convective downdrafts. We used cloud-resolving numerical simulations to investigate the transport of MSE into the boundary layer and found turbulent entrainment between clouds to be the dominant process.

  19. Air Quality System (AQS)

    EPA Pesticide Factsheets

    The Air Quality System (AQS) database contains measurements of air pollutant concentrations from throughout the United States and its territories. The measurements include both criteria air pollutants and hazardous air pollutants.

  20. Reflection of an acoustic wave from a bubble layer of finite thickness

    NASA Astrophysics Data System (ADS)

    Gubaidullin, D. A.; Fedorov, Yu. V.

    2016-10-01

    The problem of reflection of an acoustic wave from a two-layer medium containing a layer of bubble liquid is considered. The wave reflectance for a water-water mixture with an air bubble-air mixture is calculated and compared with experimental data. The parameters of the problem at which the reflectance takes extreme values are found and illustrated.

  1. Bioinspired air-retaining nanofur for drag reduction.

    PubMed

    Kavalenka, Maryna N; Vüllers, Felix; Lischker, Simone; Zeiger, Claudia; Hopf, Andreas; Röhrig, Michael; Rapp, Bastian E; Worgull, Matthias; Hölscher, Hendrik

    2015-05-27

    Bioinspired nanofur, covered by a dense layer of randomly distributed high aspect ratio nano- and microhairs, possesses superhydrophobic and air-retaining properties. Nanofur is fabricated using a highly scalable hot pulling method in which softened polymer is elongated with a heated sandblasted plate. Here we investigate the stability of the underwater air layer retained by the irregular nanofur topography by applying hydraulic pressure to the nanofur kept underwater, and evaluate the gradual changes in the air-covered area. Furthermore, the drag reduction resulting from the nanofur air retention is characterized by measuring the pressure drop across channels with and without nanofur.

  2. Airborne survey of major air basins in California

    NASA Technical Reports Server (NTRS)

    Gloria, H. R.; Bradburn, G.; Reinisch, R. F.; Pitts, J. N., Jr.; Behar, J. V.; Zafonte, L.

    1974-01-01

    An instrumented aircraft was used to study the chemical and transport properties of air pollution in two major urban centers in California and to survey certain aspects of air pollution within this state. State-of-the-art measurement techniques and sampling procedures are discussed. It is found that meteorological transport mechanisms are better portrayed by vertical pollutant profiles. Airborne measurements define the nature of the mixing layer for atmospheric pollutants. Results show that the pollutants are found to be concentrated in distinct layers up to at least 18,000 feet and the O3 buildup occurring in advected air masses is a result of a continuous photochemical aging of air mass.

  3. Modelling Layer parallel stylolites

    NASA Astrophysics Data System (ADS)

    Koehn, Daniel; Pataki Rood, Daisy; Beaudoin, Nicolas

    2016-04-01

    We modeled the geometrical roughening of mainly layer-dominated stylolites in order to understand their structural evolution, to present an advanced classification of stylolite shapes and to relate this classification to chemical compaction and stylolite sealing capabilities. Our simulations show that layer-dominated stylolites can grow in three distinct stages, an initial slow nucleation, a fast layer-pinning phase and a final freezing stage if the layer dissolves completely during growth. Dissolution of the pinning layer and thus destruction of the compaction tracking capabilities is a function of the background noise in the rock and the dissolution rate of the layer itself. Low background noise needs a slower dissolving layer for pinning to be successful but produces flatter teeth than higher background noise. We present an advanced classification based on our simulations and separate stylolites into four classes: rectangular layer type, seismogram pinning type, suture/sharp peak type and simple wave-like type.

  4. Basic Ozone Layer Science

    EPA Pesticide Factsheets

    Learn about the ozone layer and how human activities deplete it. This page provides information on the chemical processes that lead to ozone layer depletion, and scientists' efforts to understand them.

  5. Map of restriction sites on bacteriophage T4 cytosine-containing DNA for endonucleases bamHI, BglII, KpnI, PvuI, SalI, and XbaI.

    PubMed Central

    Marsh, R C; Hepburn, M L

    1981-01-01

    A complete map of the cleavage sites of restriction endonucleases BamHI, BglII, KpnI, PvuI, SalI, and XbaI was determined for the cytosine-containing DNA of a bacteriophage T4 alc mutant. The 56 sequence-specific sites were assigned map coordinates based on a least-squares analysis of measured fragment lengths. Altogether, the lengths of 118 fragments from single and double enzyme digestions were measured by electrophoresis of the fragments in agarose gels. DNA fragments of known sequence or DNA fragments calibrated with fragments of known sequence were used as standards. The greatest deviation between an experimentally measured fragment length and its computed map coordinates was 3.0%; the average deviation was 0.8%. The total length of the wild-type T4 genome was calculated to be 166,200 base pairs. Images PMID:6264096

  6. Air cell

    NASA Astrophysics Data System (ADS)

    Okamura, Okiyoshi; Wakasa, Masayuki; Tamanoi, Yoshihito

    1991-04-01

    The present invention relates to an air cell. This air cell provides a compact light-weight power source for model aircraft permitting them to fly for an extended period so that they may be used for such practical purposes as crop dusting, surveying, and photographing. The cell is comprised of a current collector so disposed between a magnesium, zinc, or aluminum alloy cathode and a petroleum graphite anode that it is in contact with the anode. The anode is formed by adding polytetrafluoroethylene dispersion liquid in a mixture of active carbon and graphite powder, pouring the mixture into a mold and heating it to form the anode. It is fabricated by a plurality of anode sections and is formed with at least one hole so that it can provide a cell which is compact in size and light in weight yet is capable of generating a high output. The anode, the cathode, and a separator are wetted by an electrolytic liquid. The electrolyte is continuously supplied through the life of the cell.

  7. Layer-by-layer cell membrane assembly

    NASA Astrophysics Data System (ADS)

    Matosevic, Sandro; Paegel, Brian M.

    2013-11-01

    Eukaryotic subcellular membrane systems, such as the nuclear envelope or endoplasmic reticulum, present a rich array of architecturally and compositionally complex supramolecular targets that are as yet inaccessible. Here we describe layer-by-layer phospholipid membrane assembly on microfluidic droplets, a route to structures with defined compositional asymmetry and lamellarity. Starting with phospholipid-stabilized water-in-oil droplets trapped in a static droplet array, lipid monolayer deposition proceeds as oil/water-phase boundaries pass over the droplets. Unilamellar vesicles assembled layer-by-layer support functional insertion both of purified and of in situ expressed membrane proteins. Synthesis and chemical probing of asymmetric unilamellar and double-bilayer vesicles demonstrate the programmability of both membrane lamellarity and lipid-leaflet composition during assembly. The immobilized vesicle arrays are a pragmatic experimental platform for biophysical studies of membranes and their associated proteins, particularly complexes that assemble and function in multilamellar contexts in vivo.

  8. Photonic layered media

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu

    2002-01-01

    A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

  9. Scintillator reflective layer coextrusion

    DOEpatents

    Yun, Jae-Chul; Para, Adam

    2001-01-01

    A polymeric scintillator has a reflective layer adhered to the exterior surface thereof. The reflective layer comprises a reflective pigment and an adhesive binder. The adhesive binder includes polymeric material from which the scintillator is formed. A method of forming the polymeric scintillator having a reflective layer adhered to the exterior surface thereof is also provided. The method includes the steps of (a) extruding an inner core member from a first amount of polymeric scintillator material, and (b) coextruding an outer reflective layer on the exterior surface of the inner core member. The outer reflective layer comprises a reflective pigment and a second amount of the polymeric scintillator material.

  10. Transitioning to Low-GWP Alternatives in Unitary Air Conditioning

    EPA Pesticide Factsheets

    This fact sheet provides current information on low-Global Warming Potential (GWP) refrigerant alternatives used in unitary air-conditioning equipment, relevant to the Montreal Protocol on Substances that Deplete the Ozone Layer.

  11. Joint Air Sea Interaction (JASIN) experiment, Northwest coast of Scotland

    NASA Technical Reports Server (NTRS)

    Businger, J. A.

    1981-01-01

    The joint air sea interaction (JASIN) experiment took place off the Northwest coast of Scotland. Sea surface and boundary layer parameters were measured. The JASIN data was used as ground truth for various sensors on the SEASAT satellite.

  12. A FEDERATED PARTNERSHIP FOR URBAN METEOROLOGICAL AND AIR QUALITY MODELING

    EPA Science Inventory

    Recently, applications of urban meteorological and air quality models have been performed at resolutions on the order of km grid sizes. This necessitated development and incorporation of high resolution landcover data and additional boundary layer parameters that serve to descri...

  13. Air pollution modeling and its application III

    SciTech Connect

    De Wispelaere, C.

    1984-01-01

    This book focuses on the Lagrangian modeling of air pollution. Modeling cooling tower and power plant plumes, modeling the dispersion of heavy gases, remote sensing as a tool for air pollution modeling, dispersion modeling including photochemistry, and the evaluation of model performances in practical applications are discussed. Specific topics considered include dispersion in the convective boundary layer, the application of personal computers to Lagrangian modeling, the dynamic interaction of cooling tower and stack plumes, the diffusion of heavy gases, correlation spectrometry as a tool for mesoscale air pollution modeling, Doppler acoustic sounding, tetroon flights, photochemical air quality simulation modeling, acid deposition of photochemical oxidation products, atmospheric diffusion modeling, applications of an integral plume rise model, and the estimation of diffuse hydrocarbon leakages from petrochemical factories. This volume constitutes the proceedings of the Thirteenth International Technical Meeting on Air Pollution Modeling and Its Application held in France in 1982.

  14. The enhancement mechanism of thin plasma layer on antenna radiation

    SciTech Connect

    Wang, Chunsheng Jiang, Binhao; Li, Xueai

    2015-03-09

    A model of plasma-antenna is carried out to study the radiation enhancement mechanism of antenna covered by thin plasma layer. The results show when the radiation intensity achieves maximum, a region of equal electric field is formed due to the reflection of electric field at the interface of plasma and air. The plasma layer acted as an extension of the antenna. Furthermore, the shape of plasma layer is changed to verify the effect of plasma boundary on antenna radiation. The study shows the effect of thin plasma layer on electromagnetic field and provides a type of plasma antenna.

  15. Catalytic properties of composite amorphous carbon-platinum layers in fuel cells

    SciTech Connect

    Nechitailov, A. A. Zvonareva, T. K.; Remenyuk, A. D.; Tolmachev, V. A.; Goryachev, D. N.; El'tsina, O. S.; Belyakov, L. V.; Sreseli, O. M.

    2008-10-15

    Catalytic properties of composite amorphous carbon-platinum layers produced by magnetron cosputtering have been studied. The layers were characterized by electron microscopy, IR spectroscopy, ellipsometry, gravimetry, and spectrophotometric chemical analysis. The catalytic activity of the layers was studied in an air-hydrogen fuel cell by measuring its load and power characteristics.

  16. Metal-Air Batteries

    SciTech Connect

    Zhang, Jiguang; Bruce, Peter G.; Zhang, Gregory

    2011-08-01

    Metal-air batteries have much higher specific energies than most currently available primary and rechargeable batteries. Recent advances in electrode materials and electrolytes, as well as new designs on metal-air batteries, have attracted intensive effort in recent years, especially in the development of lithium-air batteries. The general principle in metal-air batteries will be reviewed in this chapter. The materials, preparation methods, and performances of metal-air batteries will be discussed. Two main metal-air batteries, Zn-air and Li-air batteries will be discussed in detail. Other type of metal-air batteries will also be described.

  17. Piezoelectric Resonator with Two Layers

    NASA Technical Reports Server (NTRS)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  18. Layer Precipitable Water (LPW) Briefing

    NASA Technical Reports Server (NTRS)

    Forsythe, John; Kidder, Stan; Fuell, Kevin; LeRoy, Anita

    2013-01-01

    Microwave Integrated Retrieval System (MIRS) provides soundings of specific humidity from a variety of instruments and is combined with AIRS infrared soundings to create a Layered Precipitable Water (LPW) composite product. The LPW provides vertical moisture information in the column instead of just upper levels via WV imagery, or a single column value via TPW products. LPW is created every 3 hours using the last 12 hours worth of data and has a delivery latency of 40 minutes. Weaknesses include discontinuities in the composite. Strengths include seeing through clouds, over land usage, and greater spatial coverage of vertical moisture profiles. Applications of LPW include analysis of horizontal and vertical moisture gradients, verification of NWP moisture, and analysis of atmospheric rivers and other moisture advection. Operational testbed is ongoing to determine viability of wider distribution.

  19. Locating the mixing layer: algorithms to identify the mixing layer height using lidar signals

    NASA Astrophysics Data System (ADS)

    Mehnert, Jan; Pesch, Markus

    2007-10-01

    The mixing layer (ML) provides a vertical atmospheric barrier and its height has become an important parameter in meteorology and air quality control. In locating the mixing layer using Lidar it has always to be considered that the signals may be biased by noise and the mixing layer itself can contain more than a single layer. In previous studies use was made of the fact that the main part of aerosols are located within the mixing layer and outside this layer, in the so called free atmosphere, the concentration of aerosols decreased significantly. This leads to a sharp change of the backscattering signal at the boundary layers. In this paper an algorithm is presented that determines the height of the mixing layer (MLH) by an intensive analysis of the global and local maxima of the Lidar signal and its first derivative. The algorithm searches for a maximum of the backscatter signal followed by a minimum in the first derivative. The results are compared with the MLH calculated by a model.

  20. Electrochemical Atomic Layer Processing

    DTIC Science & Technology

    1994-06-25

    where an atomic layer of an element is deposited , or removed, in a surface limited reaction. The potentials used are referred to as underpotentials in...the electrochemical literature. The atomic layer deposition process is referred to as underpotential deposition (UPD). 14. SUBJECT TERMS 15, NUMBER OF...reaction. The potentials used are referred to as underpotentials in the electrochemical literature. The atomic layer deposition process is referred to as

  1. Layered plasma polymer composite membranes

    DOEpatents

    Babcock, W.C.

    1994-10-11

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

  2. Indoor Air Quality

    MedlinePlus

    ... can protect yourself and your family. Learn more Air Quality at Work Workers should breathe easy while on the job, but worksites with poor air quality put employees at risk. Healthy air is essential ...

  3. Air Sensor Toolbox

    EPA Pesticide Factsheets

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  4. HEPA air filter (image)

    MedlinePlus

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  5. Needed: Clean Air.

    ERIC Educational Resources Information Center

    Schneider, Gerald

    1979-01-01

    Provides information on air pollution for young readers. Discusses damage to substances and sickness from air pollution, air quality, and what to do in a pollution alert. Includes questions with answers, illustrations, and activities for the learner. (MA)

  6. Process for depositing Cr-bearing layer

    DOEpatents

    Ellis, T.W.; Lograsso, T.A.; Eshelman, M.A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate. 7 figs.

  7. Process for depositing Cr-bearing layer

    DOEpatents

    Ellis, Timothy W.; Lograsso, Thomas A.; Eshelman, Mark A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate.

  8. High efficiency air cycle air conditioning system

    SciTech Connect

    Rannenberg, G. C.

    1985-11-19

    An air cycle air conditioning system is provided with regenerative heat exchangers upstream and downstream of an expansion turbine. A closedloop liquid circulatory system serially connects the two regenerative heat exchangers for regeneration without the bulk associated with air-to-air heat exchange. The liquid circulatory system may also provide heat transport to a remote sink heat exchanger and from a remote load as well as heat exchange within the sink heat exchanger and load for enhanced compactness and efficiency.

  9. Air Pollution Monitoring | Air Quality Planning & Standards ...

    EPA Pesticide Factsheets

    2016-06-08

    The basic mission of the Office of Air Quality Planning and Standards is to preserve and improve the quality of our nation's air. To accomplish this, OAQPS must be able to evaluate the status of the atmosphere as compared to clean air standards and historical information.

  10. Layers and Erosion and more Layers

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 4 November 2003

    This image is located within a set of eroded layered rocks known as the Medusae Fossae Formation. Careful inspection of this image reveals four separate layers. Starting at the bottom of the image, as well as the bottom of the sequence of layers, is a somewhat hilly, cratered plain. Above that is a mud or lava flow with a lobate edge that is characteristic of fluid flow. Above that is a layer with a spectacular rayed crater. This layer shows linear erosional patterns that are probably caused by persistent wind abrasion, typical of rocks in this area. And finally, a more blocky unit lies on top, mostly eroded away.

    Image information: VIS instrument. Latitude 3.6, Longitude 218.6 East (141.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  11. Phenotypic characterization and 16S rDNA identification of culturable non-obligate halophilic bacterial communities from a hypersaline lake, La Sal del Rey, in extreme South Texas (USA)

    PubMed Central

    2012-01-01

    Background La Sal del Rey ("the King's Salt") is one of several naturally-occurring salt lakes in Hidalgo County, Texas and is part of the Lower Rio Grande Valley National Wildlife Refuge. The research objective was to isolate and characterize halophilic microorganisms from La Sal del Rey. Water samples were collected from the lake and a small creek that feeds into the lake. Soil samples were collected from land adjacent to the water sample locations. Sample salinity was determined using a refractometer. Samples were diluted and cultured on a synthetic saline medium to grow halophilic bacteria. The density of halophiles was estimated by viable plate counts. A collection of isolates was selected, gram-stained, tested for catalase, and characterized using API 20E® test strips. Isolates were putatively identified by sequencing the 16S rDNA. Carbon source utilization by the microbial community from each sample site was examined using EcoPlate™ assays and the carbon utilization total activity of the community was determined. Results Results showed that salinity ranged from 4 parts per thousand (ppt) at the lake water source to 420 ppt in water samples taken just along the lake shore. The density of halophilic bacteria in water samples ranged from 1.2 × 102 - 5.2 × 103 colony forming units per ml (cfu ml-1) whereas the density in soil samples ranged from 4.0 × 105 - 2.5 × 106 colony forming units per gram (cfu g-1). In general, as salinity increased the density of the bacterial community decreased. Microbial communities from water and soil samples were able to utilize 12 - 31 carbon substrates. The greatest number of substrates utilized was by water-borne communities compared to soil-based communities, especially at lower salinities. The majority of bacteria isolated were gram-negative, catalase-positive, rods. Biochemical profiles constructed from API 20E® test strips showed that bacterial isolates from low-salinity water samples (4 ppt) showed the greatest

  12. Magnetostratigraphic, biostratigraphic, and stable isotope stratigraphy of an Upper Miocene drill core from the Salé Briqueterie (northwestern Morocco): A high-resolution chronology for the Messinian stage

    NASA Astrophysics Data System (ADS)

    Hodell, David A.; Benson, Richard H.; Kent, Dennis V.; Boersma, Anne; Rakic-El Bied, Kruna

    1994-12-01

    We report a high-resolution stable isotope, carbonate, magnetostratigraphic, and biostratigraphic record from a 175-m drill core from the Salé Briqueterie, which is part of the Bou Regreg section in northwestern Morocco. The Salé drill core spans the interval from paleomagnetic Chron C4n partim to C3r (earliest Gilbert), which represents the time leading up to and including the isolation and desiccation of the Mediterranean (i.e., the Messinian salinity crisis). During Chrons C3An and C3Ar (6.935 to 5.894 Ma) the isotope and carbonate signals display quasi-periodic variations with estimated periods of 40 and 100 kyr, respectively. We interpret the 40-kyr δ18O variations as reflecting changes in global ice volume caused by obliquity-induced changes (41 kyr) in solar insolation in polar regions. The 100-kyr carbonate variations probably represent long-term modulation of the amplitude of the precessional cycle (˜21 kyr), which is not resolved by our sampling frequency. The cyclic nature of the oxygen isotope signal permits us to extend the isotope nomenclature of Shackleton et al. (1994a) from stage TG24 in Chron C3r (earliest Gilbert) to stage C3Ar.δ18O.18 at the base of Chron C3Ar (6.935 Ma). A major change in paleoceanographic conditions is recorded across the Tortonian/Messinian boundary, which we correlate to Chron C3Bn at 7.04 Ma. Benthic foraminiferal δ18O values increased by an average of 0.4‰ in two steps at 7.17 Ma and 6.8 Ma and δ13C values decreased by 0.7-0.8‰ between 7.1 and 6.8 Ma, representing the late Miocene carbon shift. The first step in δ18O values coincides with an inferred reversal in deep water circulation through the Rifian Corridor, and the second correlates with the base of the Tripoli Formation and onset of "crisis conditions" in the Mediterranean. We suggest that the increase in δ18O values represents, at least in part, an increase in global ice volume that lowered sea level and contributed to the establishment of a negative

  13. Primary zone air proportioner

    DOEpatents

    Cleary, Edward N. G.

    1982-10-12

    An air proportioner is provided for a liquid hydrocarbon fueled gas turbine of the type which is convertible to oil gas fuel and to coal gas fuel. The turbine includes a shell for enclosing the turbine, an air duct for venting air in said shell to a gasifier, and a fuel injector for injecting gasified fuel into the turbine. The air proportioner comprises a second air duct for venting air from the air duct for mixing with fuel from the gasifier. The air can be directly injected into the gas combustion basket along with the fuel from the injector or premixed with fuel from the gasifier prior to injection by the fuel injector.

  14. Coating of porous carbon for use in lithium air batteries

    DOEpatents

    Amine, Khalil; Lu, Jun; Du, Peng; Lei, Yu; Elam, Jeffrey W

    2015-04-14

    A cathode includes a carbon material having a surface, the surface having a first thin layer of an inert material and a first catalyst overlaying the first thin layer, the first catalyst including metal or metal oxide nanoparticles, wherein the cathode is configured for use as the cathode of a lithium-air battery.

  15. Multiple density layered insulator

    DOEpatents

    Alger, Terry W.

    1994-01-01

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  16. Multiple density layered insulator

    DOEpatents

    Alger, T.W.

    1994-09-06

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  17. Early Results from AIRS/AMSU/HSB

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Barnet, Christopher; Blaisdell, John; Iredell, Lena; Keita, Fricky; Kouvaris, Lou

    2003-01-01

    AIRS was launched on EOS Aqua on May 5, 2002, together with AMSU A and HSB, to form a next generation polar orbiting infiared and microwave atmospheric sounding system. The primary products of AIRS/AMSU/HSB are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of lK, and layer precipitable water with an rms error of 20%, in cases with up to 80% effective cloud cover. Pre-launch simulation studies indicated that these results should be achievable. Minor modifications have been made to the pre-launch retrieval algorithm as described in this paper. Sample fields of parameters retrieved from AIRS/AMSU/HSB data are presented and validated as a function of retrieved fractional cloud cover. As in simulation, the degradation of retrieval accuracy with increasing cloud cover is small. Select fields are also compared to those contained in the ECMWF analysis, done without the benefit of AIRS data, to demonstrate information that AIRS can add to that already contained in the ECMWF analysis.

  18. Deep learning architecture for air quality predictions.

    PubMed

    Li, Xiang; Peng, Ling; Hu, Yuan; Shao, Jing; Chi, Tianhe

    2016-11-01

    With the rapid development of urbanization and industrialization, many developing countries are suffering from heavy air pollution. Governments and citizens have expressed increasing concern regarding air pollution because it affects human health and sustainable development worldwide. Current air quality prediction methods mainly use shallow models; however, these methods produce unsatisfactory results, which inspired us to investigate methods of predicting air quality based on deep architecture models. In this paper, a novel spatiotemporal deep learning (STDL)-based air quality prediction method that inherently considers spatial and temporal correlations is proposed. A stacked autoencoder (SAE) model is used to extract inherent air quality features, and it is trained in a greedy layer-wise manner. Compared with traditional time series prediction models, our model can predict the air quality of all stations simultaneously and shows the temporal stability in all seasons. Moreover, a comparison with the spatiotemporal artificial neural network (STANN), auto regression moving average (ARMA), and support vector regression (SVR) models demonstrates that the proposed method of performing air quality predictions has a superior performance.

  19. NewChallengesThreateningtheOzoneLayer

    NASA Astrophysics Data System (ADS)

    Abubakar, B.

    2007-05-01

    Since the beginning of the 1990's when the importation of fairly used Refrigerators, Air-conditioners and propellants that can easily go broken containing chlorofluorocarbon substances that is capable of destroying the Ozone layer started in commercial quantity in Africa, the African refuse mountains began metamorphosing into mountains of dumped broken Refrigerators, Air-conditioners and Propellants which are collectively becoming a threat to the Ozone layer, because of the continuous discharging of the Chlorofluorocarbon gases by the refuse in to the atmosphere in each passing second.. Nobody can actually quantify the numbers of Refrigerators, Air-conditioners and Propellants imported and disposed in Africa over the last fifteen years, but the facts still remains that the numbers of metamorphosing mountains keeps on increasing in both size and numbers in each passing day. They have even become sources of raw materials for the local blacksmiths, children and refrigerators repairers who use parts of the dumped refrigerators, Air-conditioners and Propellants for their constructions, toys and repairs respectively. This explains the reason why despite the global efforts toward protecting the Ozone layer by the United Nations (UN), governments, International Organizations and climatologist among many others, but yet the hole in the Ozone layer keeps on expanding and the global temperature keeps on rising which resulted in the unusual phenomenon like the hurricanes "Katrina" and "Rita" the unusual floods in China, Thailand, Mozambique and to some extent even the Tsunami disaster that claims millions of lives in 2004.The Rapid rising in temperature of the Tropical world countries and increase in the cases of cancer patients among many other unusual happenings over the last eight years. It was in review of the above situation that this research work was conducted and came up with the under listed suggestions/Recommendations: 1. The UN should use its capacity to discourage

  20. Oxygen-selective immobilized liquid membranes for operation of lithium-air batteries in ambient air

    SciTech Connect

    Zhang, Jian; Xu, Wu; Liu, Wei

    2010-11-01

    In this paper, nonaqueous-electrolyte-based Li-air batteries with O2-selective immobilized liquid membranes have been developed and operated in ambient air with 20~30% relative humidity(RH). Continuous anhydrous O2 can be supplied from the ambient through a membrane barrier layer at interface of the cathode and ambient air. The membranes allow O2 permeate through while blocking moisture. These membranes were prepared by loading O2-selective liquid fluids such as silicone oils into porous supports such as porous metal sheets and Teflon (PTFE) films. It was found that silicone oil of high viscosity shows better performance. The membrane performance was not affected by the oil loading temperature. The immobilized silicone oil (viscosity 100,000cst) membrane in porous PTFE film enabled the Li-air batteries with Ketjen black carbon air electrodes to operate in ambient air (with 20% RH) for 16.3 days with a specific capacity of 789 mAh/g carbon and a specific energy of 2182 Wh/kg carbon. Its performance is much better than reference battery assembled with the same battery material but by use of a commercial, porous PTFE diffusion membranes as the moisture barrier layer on the cathode, which only had a discharge time of 5.5 days corresponding to a specific capacity of 267 mAh/g carbon and a specific energy of 704 Wh/kg carbon. The Li-air battery with the present selective membrane barrier layer even showed better performance in ambient air operation (20% RH) than the reference battery tested in the dry air box (< 1% RH).

  1. Bifunctional air electrodes containing elemental iron powder charging additive

    DOEpatents

    Liu, Chia-tsun; Demczyk, Brian G.; Gongaware, Paul R.

    1982-01-01

    A bifunctional air electrode for use in electrochemical energy cells is made, comprising a hydrophilic layer and a hydrophobic layer, where the hydrophilic layer essentially comprises a hydrophilic composite which includes: (i) carbon; (ii) elemental iron particles having a particle size of between about 25 microns and about 700 microns diameter; (iii) an oxygen evolution material; (iv) a nonwetting agent; and (v) a catalyst, where at least one current collector is formed into said composite.

  2. S-layers as patterning structures and supporting layers for biomimetic membranes

    NASA Astrophysics Data System (ADS)

    Pum, Dietmar; Wetzer, Barbara; Schuster, Bernhard; Sleytr, Uwe B.

    1997-03-01

    A new approach in nanostructure technology particularly in the functionalization of surfaces has been developed on the basis of crystalline bacterial cell surface layers (S- layers). S-layers are composed of monomolecular arrays of identical (glyco)proteins showing high molecular order, defined mass distribution and isoporosity, and a high binding capacity for functional macromolecules. The possibility for recrystallizing isolated S-layer subunits into large isoporous, coherent lattices at solid supports, at the air/water interface or on lipid films and for handling such layers by standard Langmuir-Blodgett techniques opens a broad spectrum of applications in basic and applied membrane research. S-layer supported functional phospholipid bilayers or tetraether lipid films mimic the molecular architecture of those archaebacterial cell envelopes that are exclusively composed of an S-layer and a plasma membrane. This novel concept could lead to new techniques for exploiting large scale structural and functional principles of membrane associated and integrated molecules (e.g. ion channels, proton pumps, receptors).

  3. Conserved variable analysis of the convective boundary layer thermodynamic structure over the tropical oceans

    NASA Technical Reports Server (NTRS)

    Betts, Alan K.; Albrecht, Bruce A.

    1987-01-01

    An analysis of FGGE dropwindsonde data using conserved thermodynamic variables shows mixing line structures for the convective boundary layer over the equatorial Pacific. Deeper boundary layers show a double structure. Reversals of the gradients of mixing ratio and equivalent potential temperature above the boundary-layer top are present in all the averages and suggest that the origin of the air sinking into the boundary layer needs further study.

  4. Poling effect of a charge-trapping layer in glass waveguides

    NASA Astrophysics Data System (ADS)

    Ren, Y.; Marckmann, C. J.; Jacobsen, R. S.; Kristensen, M.

    Germanium-doped multi-layer waveguides containing a silicon oxy-nitride layer as a charge trapper are thermally poled in an air environment. Compared to the waveguides without the trapping layer, the induced linear electro-optic coefficient increases more than 20%. A comparable rise in the internal field is found. Our results demonstrate an optimization of the optical nonlinearity by shaping the built-in internal field with the charge-trapping layer.

  5. Pseudohomogeneous catalyst layer model for polymer electrolyte fuel cell

    NASA Astrophysics Data System (ADS)

    Springer, T. E.; Gottesfeld, S.

    We have developed a relatively simple one-dimensional model for the cathode catalyst layer. This model explains certain observed polarization curve features at higher current densities. These features include a change in linear slope, instead of a sharp limiting current feature, and a lower than expected ratio of current density measured using O2 relative to air. Diffusional paths, ionic resistance, and catalyst sites are intimately coupled in a pseudohomogeneous layer using 'effective' parameters.

  6. The Clean Air Game.

    ERIC Educational Resources Information Center

    Avalone-King, Deborah

    2000-01-01

    Introduces the Clean Air game which teaches about air quality and its vital importance for life. Introduces students to air pollutants, health of people and environment, and possible actions individuals can take to prevent air pollution. Includes directions for the game. (YDS)

  7. REACH. Air Conditioning Units.

    ERIC Educational Resources Information Center

    Garrison, Joe; And Others

    As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of air conditioning. The instructional units focus on air conditioning fundamentals, window air conditioning, system and installation, troubleshooting and…

  8. Healthy Air Outdoors

    MedlinePlus

    ... families and can even shorten their lives. Outdoor Air Pollution and Health Outdoor air pollution continues to threaten the lives and health of ... sources such as fires and dust contribute to air pollution. Learn more Fighting for Healthy Air The American ...

  9. The Application of Layer Theory to Design: The Control Layer

    ERIC Educational Resources Information Center

    Gibbons, Andrew S.; Langton, Matthew B.

    2016-01-01

    A theory of design layers proposed by Gibbons ("An Architectural Approach to Instructional Design." Routledge, New York, 2014) asserts that each layer of an instructional design is related to a body of theory closely associated with the concerns of that particular layer. This study focuses on one layer, the control layer, examining…

  10. Reversible air electrodes integrated with an anion-exchange membrane for secondary air batteries

    NASA Astrophysics Data System (ADS)

    Fujiwara, Naoko; Yao, Masaru; Siroma, Zyun; Senoh, Hiroshi; Ioroi, Tsutomu; Yasuda, Kazuaki

    Reversible air electrodes integrated with a polymer electrolyte membrane have been proposed for use in rechargeable metal-air batteries or unitized regenerative fuel cells to reduce the impact of atmospheric carbon dioxide. Reversible air electrodes were prepared with an anion-exchange membrane (AEM) as a polymer electrolyte membrane and platinum-based catalysts. The AEM at the interface between the alkaline electrolyte and the air electrode layer plays major roles in AEM-type air electrodes as follows: it blocks (a) the permeation of cations in the alkaline electrolyte into the air electrode layer to prevent carbonate precipitation, (b) penetration of the alkaline solution itself, and (c) neutralization of the alkaline electrolyte by carbon dioxide, all of which prevent performance degradation of oxygen reactions. Catalysts for decreasing the overvoltage of oxygen reactions were also investigated with the AEM-type air electrode, and the overall efficiency was improved due to a remarkable decrease in the potential for the oxygen evolution reaction with Pt-Ir catalysts.

  11. CALIPSO Observations of Transatlantic Dust: Vertical Stratification and Effect of Clouds

    NASA Technical Reports Server (NTRS)

    Yang, Weidong; Marshak, Alexander; Varnai, Tamas; Kalashnikova, Olga V.; Kostinski, Alexander B.

    2014-01-01

    We use CALIOP nighttime measurements of lidar backscatter, color and depolarization ratios, as well as particulate retrievals during the summer of 2007 to study transatlantic dust properties downwind of Saharan sources, and to examine the influence of nearby clouds on dust. Our analysis suggests that (1) under clear skies, while lidar backscatter and color ratio do not change much with altitude and longitude in the Saharan Air Layer (SAL), depolarization ratio increases with altitude and decreases westward in the SAL (2) the vertical lapse rate of dust depolarization ratio, introduced here, increases within SAL as plumes move westward (3) nearby clouds barely affect the backscatter and color ratio of dust volumes within SAL but not so below SAL. Moreover, the presence of nearby clouds tends to decrease the depolarization of dust volumes within SAL. Finally, (4) the odds of CALIOP finding dust below SAL next to clouds are about of those far away from clouds. This feature, together with an apparent increase in depolarization ratio near clouds, indicates that particles in some dust volumes loose asphericity in the humid air near clouds, and cannot be identified by CALIPSO as dust.

  12. CALIPSO Observations of Transatlantic Dust: Vertical Stratification and Effect of Clouds

    NASA Technical Reports Server (NTRS)

    Yang, Weidong; Marshak, Alexander; Varnai, Tamas; Kalashnikova, Olga V.; Kostinski, Alexander B.

    2012-01-01

    CALIOP nighttime measurements of lidar backscatter, color and depolarization ratios during the summer of 2007 are used to study transatlantic dust properties downwind of Saharan sources, and to examine the interaction of clouds and dust. We discuss the following findings: (1) while lidar backscatter doesn't change much with altitude in the Saharan Air Layer (SAL), depolarization and color ratios both increase with altitude in the SAL; (2) lidar backscatter and color ratio increase as dust is transported westward in the SAL; (3) the vertical lapse rate of dust depolarization ratio increases within SAL as plumes move westward; (4) nearby clouds barely affect the backscatter and color ratio of dust volumes within SAL but not so below SAL. Finally, (5) the odds of CALIOP finding dust below SAL next to clouds are about 2/3 of those far away from clouds. This feature, together with an apparent increase in depolarization ratio near clouds, indicates that particles in some dusty volumes lose asphericity in the humid air near clouds, and cannot be identified by CALIPSO as dust.

  13. Layering in halocarbons, methane, nitrous oxide, ozone, and water vapour over mid-latitudes

    NASA Technical Reports Server (NTRS)

    Orsolini, Yvan J.; Karcher, Fernand; Manney, Gloria L.; Engel, Andreas; Ovarlez, Joelle; Claud, Chantal

    1997-01-01

    The purpose of the balloon flights performed in March 1993 from Aire-sur-Adour (France) was to measure trace gases in the polar vortex during a dynamically active period. These balloon flights revealed coincident layering in long-lived tropospheric source gases. A layer of mid-latitude air, enriched in trace gases, was detected at sampled levels near 15 mbar. High resolution advection models, fine scale distributions of ozone, nitrous oxide, methane, and halocarbons were constructed. The calculations showed how air enriched in trace gases is sampled near 15 mbar when a filament of such air is drawn into the outer portion of the vortex.

  14. Compliant layer chucking surface

    DOEpatents

    Blaedel, Kenneth L.; Spence, Paul A.; Thompson, Samuel L.

    2004-12-28

    A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

  15. Concentric layer ramjet fuel

    SciTech Connect

    Burdette, G.W.; Francis, J.P.

    1988-03-08

    This patent describes a solid fuel ramjet grain comprising concentric layers of solid ramjet fuel having a perforation therethrough along the center axis of the grain. The performation is connected to a combustion after-chamber. The solid ramjet fuel layers comprises a pure hydroxyl-terminated polybutadiene hydrocarbon fuel or a mixture of a hydroxyl-terminated polybutadiene hydrocarbon fuel and from about 5 to about 60 percent by weight of an additive to increase the fuel regression rate selected from the group consisting of magnesium, boron carbide, aluminum, and zirconium such that, when buried in the operation of the ramjet, each fuel layer produces a different level of thrust.

  16. Multi-layer coatings

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  17. Merging of OMI and AIRS Ozone Data

    NASA Technical Reports Server (NTRS)

    Labow, Gordon J.; Fisher, Bradford; Susskind, Joel

    2014-01-01

    The OMI Instrument measures ozone using the backscattered light in the UV part of the spectrum. In polar night there are no OMI measurements so we hope to incorporate the AIRS ozone data to fill in these missing regions. AIRS is on the Aqua platform and has been operating since May 2002. AIRS is a multi-detector array grating spectrometer containing 2378 IR channels between 650 per centimeter and 2760 per centimeter which measures atmospheric temperature, precipitable water, water vapor, CO, CH4, CO2 and ozone profiles and column amount. It can also measure effective cloud fraction and cloud top pressure for up to two cloud layers and sea-land skin temperature. Since 2008, OMI has had part of its aperture occulted with a piece of the thermal blanket resulting in several scan positions being unusable. We hope to use the AIRS data to fill in the missing ozone values for those missing scan positions.

  18. The Sal-like 4 - integrin α6β1 network promotes cell migration for metastasis via activation of focal adhesion dynamics in basal-like breast cancer cells.

    PubMed

    Itou, Junji; Tanaka, Sunao; Li, Wenzhao; Iida, Atsuo; Sehara-Fujisawa, Atsuko; Sato, Fumiaki; Toi, Masakazu

    2017-01-01

    During metastasis, cancer cell migration is enhanced. However, the mechanisms underlying this process remain elusive. Here, we addressed this issue by functionally analyzing the transcription factor Sal-like 4 (SALL4) in basal-like breast cancer cells. Loss-of-function studies of SALL4 showed that this transcription factor is required for the spindle-shaped morphology and the enhanced migration of cancer cells. SALL4 also up-regulated integrin gene expression. The impaired cell migration observed in SALL4 knockdown cells was restored by overexpression of integrin α6 and β1. In addition, we clarified that integrin α6 and β1 formed a heterodimer. At the molecular level, loss of the SALL4 - integrin α6β1 network lost focal adhesion dynamics, which impairs cell migration. Over-activation of Rho is known to inhibit focal adhesion dynamics. We observed that SALL4 knockdown cells exhibited over-activation of Rho. Aberrant Rho activation was suppressed by integrin α6β1 expression, and pharmacological inhibition of Rho activity restored cell migration in SALL4 knockdown cells. These results indicated that the SALL4 - integrin α6β1 network promotes cell migration via modulation of Rho activity. Moreover, our zebrafish metastasis assays demonstrated that this gene network enhances cell migration in vivo. Our findings identify a potential new therapeutic target for the prevention of metastasis, and provide an improved understanding of cancer cell migration.

  19. New challenges threatening the ozone layer

    NASA Astrophysics Data System (ADS)

    Abubakar, Babagana

    Since the beginning of the 1990's when the importation of fairly used Refrigerators, Airconditioners and propellants that can easily go broken containing chlorofluorocarbon substances that is capable of destroying the Ozone layer started in commercial quantity in Africa, the African refuse mountains began metamorphosing into mountains of dumped broken Refrigerators, Air-conditioners and Propellants which are collectively becoming a threat to the Ozone layer, because of the continuous discharging of the Chlorofluorocarbon gases by the refuse in to the atmosphere in each passing second.. Nobody can actually quantify the numbers of Refrigerators, Air-conditioners and Propellants imported and disposed in Africa over the last fifteen years, but the facts still remains that the numbers of metamorphosing mountains keeps on increasing in both size and numbers in each passing day. They have even become sources of raw materials for the local blacksmiths, children and refrigerators repairers who use parts of the dumped refrigerators, Air-conditioners and Propellants for their constructions, toys and repairs respectively. This explains the reason why despite the global efforts toward protecting the Ozone layer by the United Nations (UN), governments, International Organizations and climatologist among many others, but yet the hole in the Ozone layer keeps on expanding and the global temperature keeps on rising which resulted in the unusual phenomenon like the hurricanes "Katrina" and "Rita" the unusual floods in China, Thailand, Mozambique and to some extent even the Tsunami disaster that claims millions of lives in 2004.The Rapid rising in temperature of the Tropical world countries and increase in the cases of cancer patients among many other unusual happenings over the last eight years. It was in review of the above situation that this research work was conducted and came up with the under listed suggestions/Recommendations: 1. The UN should use its capacity to discourage

  20. Terby's Layered Rocks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    14 March 2004 Layered rock outcrops are common all across Mars, and the Mars rover, Opportunity, has recently investigated some layered rocks in Meridiani Planum. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered sedimentary rocks in northern Terby Crater, located just north of the giant Hellas Basin near 27.5oS, 285.8oW. Hundreds of layers are exposed in a deposit several kilometers thick within Terby. A history of events that shaped the northern Hellas region is recorded in these rocks, just waiting for a person or robot to investigate. The picture covers an area 3 km (1.9 mi) across. Sunlight illuminates the scene from the left.

  1. Structured luminescence conversion layer

    DOEpatents

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  2. Direct Simulation of Shock Layer Plasmas

    SciTech Connect

    Farbar, E. D.; Boyd, I. D.

    2011-05-20

    Approximate models of the electric field used with the DSMC method all impose quasi-neutrality everywhere in the shock layer plasma. The shortcomings of these models are examined in this study by simulating a weak shock layer plasma with a coupled DSMC-Particle-In-Cell (PIC) method. The stagnation streamline of an axisymmetric shock layer is simulated for entry velocities in air that correspond to both lunar and Mars return trajectories. The atmospheric densities, particle diameters and chemical reaction rates are varied from the actual values to make the computations tractable while retaining the mean free path of air at 85 km altitude. In contrast to DSMC flow field predictions, regions of non-neutrality are predicted by the DSMC-PIC method, and the electrons are predicted to be isothermal. Perhaps the most important result of this study is that the DSMC-PIC results at both reentry energies yield a 14% increase in heat flux to the vehicle surface relative to the DSMC results. Rather unintuitively, this is mostly due to an increase in ion flux to the surface, rather than the potential energy gained by each ion as it traverses the plasma sheath. In this study, an approximate electric field model is presented, with the goal of accounting for this heat flux augmentation without the need for a computationally expensive DSMC-PIC calculation of the entire flow-field. Convective heat flux results obtained with new electric field model are compared to results from the rigorous DSMC-PIC calculations.

  3. Aerosol fluxes in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Petelski, Tomasz; Zieliński, Tymon; Makuch, Przemysław; Kowalczyk, Jakub; Ponczkowska, Agnieszka; Drozdowska, Violetta; Piskozub, Jacek

    2010-05-01

    We present aerosol emission fluxes and concentrations calculated from in-situ measurement in the Nordic Sea from R/V Oceania. We compare vertical fluxes calculated with the eddy correlation and gradient methods. We use the results to test the hypothesis that marine aerosol emitted from the sea surface helps to clear the boundary layer from other aerosol particles. As the emitted droplets do not dry out in the highly humid surface layer air and because of their sizes most of them are deposited quickly at the sea surface. Therefore marine aerosol has many features of rain meaning that the deposition in the marine boundary layer in high wind events is controlled not only by the "dry" processes but also by the "wet" scavenging. We have estimated the effectiveness of the process using our own measurements of vertical aerosol fluxes in the Nordic Seas. This process could explain observed phenomenon of lower Arctic aerosol optical thickness (AOT) when the air masses moved over open sea than over sea-ice. We show a negative correlation between the sea-ice coverage in the seas adjacent to Svalbard and monthly AOT values in Ny Alesund.

  4. LiNiFe-based layered structure oxide and composite for advanced single layer fuel cells

    NASA Astrophysics Data System (ADS)

    Zhu, Bin; Fan, Liangdong; Deng, Hui; He, Yunjune; Afzal, Muhammad; Dong, Wenjing; Yaqub, Azra; Janjua, Naveed K.

    2016-06-01

    A layered structure metal oxide, LiNi0.1Fe0.90O2-δ (LNF), is explored for the advanced single layer fuel cells (SLFCs). The temperature dependent impedance profiles and concentration cells (hydrogen concentration, oxygen concentration, and H2/air atmospheres) tests prove LNF to be an intrinsically electronic conductor in air while mixed electronic and proton conductor in H2/air environment. SLFCs constructed by pure LNF materials show significant short circuiting reflected by a low device OCV and power output (175 mW cm-2 at 500 °C) due to high intrinsic electronic conduction. The power output is improved up to 640 and 760 mW cm-2, respectively at 500 and 550 °C by compositing LNF with ion conducting material, e.g., samarium doped ceria (SDC), to balance the electronic and ionic conductivity; both reached at 0.1 S cm-1 level. Such an SLFC gives super-performance and simplicity over the conventional 3-layer (anode, electrolyte and cathode) FCs, suggesting strong scientific and commercial impacts.

  5. Characterization and use of crystalline bacterial cell surface layers

    NASA Astrophysics Data System (ADS)

    Sleytr, Uwe B.; Sára, Margit; Pum, Dietmar; Schuster, Bernhard

    2001-10-01

    Crystalline bacterial cell surface layers (S-layers) are one of the most common outermost cell envelope components of prokaryotic organisms (archaea and bacteria). S-layers are monomolecular arrays composed of a single protein or glycoprotein species and represent the simplest biological membranes developed during evolution. S-layers as the most abundant of prokaryotic cellular proteins are appealing model systems for studying the structure, synthesis, genetics, assembly and function of proteinaceous supramolecular structures. The wealth of information existing on the general principle of S-layers have revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) functional groups on the surface and in the pores are aligned in well-defined positions and orientations and accessible for chemical modifications and binding functional molecules in very precise fashion; (iii) isolated S-layer subunits from a variety of organisms are capable of recrystallizing as closed monolayers onto solid supports (e.g., metals, polymers, silicon wafers) at the air-water interface, on lipid films or onto the surface of liposomes; (iv) functional domains can be incorporated in S-layer proteins by genetic engineering. Thus, S-layer technologies particularly provide new approaches for biotechnology, biomimetics, molecular nanotechnology, nanopatterning of surfaces and formation of ordered arrays of metal clusters or nanoparticles as required for nanoelectronics.

  6. Air volume measurement of 'Braeburn' apple fruit.

    PubMed

    Drazeta, Lazar; Lang, Alexander; Hall, Alistair J; Volz, Richard K; Jameson, Paula E

    2004-05-01

    The radial disposition of air in the flesh of fruit of Malus domestica Borkh., cv 'Braeburn' was investigated using a gravimetric technique based on Archimedes' principle. Intercellular air volume was measured by weighing a small tissue sample under water before and after vacuum infiltration to remove the air. In a separate procedure, the volume of the same sample was measured by recording the buoyant upthrust experienced by it when fully immersed in water. The method underestimates tissue air volume due to a slight invasion of the intercellular air spaces around the edges of the sample when it is immersed in water. To correct for this error, an adjustment factor was made based upon an analysis of a series of measurements of air volume in samples of different dimensions. In 'Braeburn' there is a gradient of declining air content from just beneath the skin to the centre of the fruit with a sharp discontinuity at the core line. Cell shape and cell packing were observed in the surface layers of freshly excised and stained flesh samples using a dissecting microscope coupled to a video camera and a PC running proprietary software. Tissue organization changed with distance below the skin. It is speculated that reduced internal gas movement, due to the tightly packed tissue of 'Braeburn' and to the potential diffusion barrier at the core line between the cortex and the pith, may increase susceptibility of the flesh to disorders associated with tissue browning and breakdown.

  7. EASI - EQUILIBRIUM AIR SHOCK INTERFERENCE

    NASA Technical Reports Server (NTRS)

    Glass, C. E.

    1994-01-01

    New research on hypersonic vehicles, such as the National Aero-Space Plane (NASP), has raised concerns about the effects of shock-wave interference on various structural components of the craft. State-of-the-art aerothermal analysis software is inadequate to predict local flow and heat flux in areas of extremely high heat transfer, such as the surface impingement of an Edney-type supersonic jet. EASI revives and updates older computational methods for calculating inviscid flow field and maximum heating from shock wave interference. The program expands these methods to solve problems involving the six shock-wave interference patterns on a two-dimensional cylindrical leading edge with an equilibrium chemically reacting gas mixture (representing, for example, the scramjet cowl of the NASP). The inclusion of gas chemistry allows for a more accurate prediction of the maximum pressure and heating loads by accounting for the effects of high temperature on the air mixture. Caloric imperfections and specie dissociation of high-temperature air cause shock-wave angles, flow deflection angles, and thermodynamic properties to differ from those calculated by a calorically perfect gas model. EASI contains pressure- and temperature-dependent thermodynamic and transport properties to determine heating rates, and uses either a calorically perfect air model or an 11-specie, 7-reaction reacting air model at equilibrium with temperatures up to 15,000 K for the inviscid flowfield calculations. EASI solves the flow field and the associated maximum surface pressure and heat flux for the six common types of shock wave interference. Depending on the type of interference, the program solves for shock-wave/boundary-layer interaction, expansion-fan/boundary-layer interaction, attaching shear layer or supersonic jet impingement. Heat flux predictions require a knowledge (from experimental data or relevant calculations) of a pertinent length scale of the interaction. Output files contain flow

  8. Isokinetic air sampler

    DOEpatents

    Sehmel, George A.

    1979-01-01

    An isokinetic air sampler includes a filter, a holder for the filter, an air pump for drawing air through the filter at a fixed, predetermined rate, an inlet assembly for the sampler having an inlet opening therein of a size such that isokinetic air sampling is obtained at a particular wind speed, a closure for the inlet opening and means for simultaneously opening the closure and turning on the air pump when the wind speed is such that isokinetic air sampling is obtained. A system incorporating a plurality of such samplers provided with air pumps set to draw air through the filter at the same fixed, predetermined rate and having different inlet opening sizes for use at different wind speeds is included within the ambit of the present invention as is a method of sampling air to measure airborne concentrations of particulate pollutants as a function of wind speed.

  9. Biocorrosion behavior of biodegradable nanocomposite fibers coated layer-by-layer on AM50 magnesium implant.

    PubMed

    Abdal-Hay, Abdalla; Hasan, Anwarul; Kim, Yu-Kyoung; Yu-Kyoung; Lee, Min-Ho; Hamdy, Abdel Salam; Khalil, Khalil Abdelrazek

    2016-01-01

    This article demonstrates the use of hybrid nanofibers to improve the biodegradation rate and biocompatibility of AM50 magnesium alloy. Biodegradable hybrid membrane fiber layers containing nano-hydroxyapatite (nHA) particles and poly(lactide)(PLA) nanofibers were coated layer-by-layer (LbL) on AM50 coupons using a facile single-step air jet spinning (AJS) approach. The corrosion performance of coated and uncoated coupon samples was investigated by means of electrochemical measurements. The results showed that the AJS 3D membrane fiber layers, particularly the hybrid membrane layers containing a small amount of nHA (3 wt.%), induce a higher biocorrosion resistance and effectively decrease the initial degradation rate compared with the neat AM50 coupon samples. The adhesion strength improved highly due to the presence of nHA particles in the AJS layer. Furthermore, the long biodegradation rates of AM50 alloy in Hank's balanced salt solution (HBSS) were significantly controlled by the AJS-coatings. The results showed a higher cytocompatibility for AJS-coatings compared to that for neat Mg alloys. The nanostructured nHA embedded hybrid PLA nanofiber coating can therefore be a suitable coating material for Mg alloy as a potential material for biodegradable metallic orthopedic implants.

  10. Tests on Double Layer Metalization

    NASA Technical Reports Server (NTRS)

    Woo, D. S.

    1983-01-01

    28 page report describes experiments in fabrication of integrated circuits with double-layer metalization. Double-layer metalization requires much less silicon "real estate" and allows more flexibility in placement of circuit elements than does single-layer metalization.

  11. Mass transfer model for two-layer TBP oxidation reactions

    SciTech Connect

    Laurinat, J.E.

    1994-09-28

    To prove that two-layer, TBP-nitric acid mixtures can be safely stored in the canyon evaporators, it must be demonstrated that a runaway reaction between TBP and nitric acid will not occur. Previous bench-scale experiments showed that, at typical evaporator temperatures, this reaction is endothermic and therefore cannot run away, due to the loss of heat from evaporation of water in the organic layer. However, the reaction would be exothermic and could run away if the small amount of water in the organic layer evaporates before the nitric acid in this layer is consumed by the reaction. Provided that there is enough water in the aqueous layer, this would occur if the organic layer is sufficiently thick so that the rate of loss of water by evaporation exceeds the rate of replenishment due to mixing with the aqueous layer. This report presents measurements of mass transfer rates for the mixing of water and butanol in two-layer, TBP-aqueous mixtures, where the top layer is primarily TBP and the bottom layer is comprised of water or aqueous salt solution. Mass transfer coefficients are derived for use in the modeling of two-layer TBP-nitric acid oxidation experiments. Three cases were investigated: (1) transfer of water into the TBP layer with sparging of both the aqueous and TBP layers, (2) transfer of water into the TBP layer with sparging of just the TBP layer, and (3) transfer of butanol into the aqueous layer with sparging of both layers. The TBP layer was comprised of 99% pure TBP (spiked with butanol for the butanol transfer experiments), and the aqueous layer was comprised of either water or an aluminum nitrate solution. The liquid layers were air sparged to simulate the mixing due to the evolution of gases generated by oxidation reactions. A plastic tube and a glass frit sparger were used to provide different size bubbles. Rates of mass transfer were measured using infrared spectrophotometers provided by SRTC/Analytical Development.

  12. EDITORIAL: Atomic layer deposition Atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Godlewski, Marek

    2012-07-01

    The growth method of atomic layer deposition (ALD) was introduced in Finland by Suntola under the name of atomic layer epitaxy (ALE). The method was originally used for deposition of thin films of sulphides (ZnS, CaS, SrS) activated with manganese or rare-earth ions. Such films were grown for applications in thin-film electroluminescence (TFEL) displays. The ALE mode of growth was also tested in the case of molecular beam epitaxy. Films grown by ALD are commonly polycrystalline or even amorphous. Thus, the name ALE has been replaced by ALD. In the 80s ALD was developed mostly in Finland and neighboring Baltic countries. Deposition of a range of different materials was demonstrated at that time, including II-VI semiconductors (e.g. CdTe, CdS) and III-V (e.g. GaAs, GaN), with possible applications in e.g. photovoltaics. The number of publications on ALD was slowly increasing, approaching about 100 each year. A real boom in interest came with the development of deposition methods of thin films of high-k dielectrics. This research was motivated by a high leakage current in field-effect transistors with SiO2-based gate dielectrics. In 2007 Intel introduced a new generation of integrated circuits (ICs) with thin films of HfO2 used as gate isolating layers. In these and subsequent ICs, films of HfO2 are deposited by the ALD method. This is due to their unique properties. The introduction of ALD to the electronics industry led to a booming interest in the ALD growth method, with the number of publications increasing rapidly to well above 1000 each year. A number of new applications were proposed, as reflected in this special issue of Semiconductor Science and Technology. The included articles cover a wide range of possible applications—in microelectronics, transparent electronics, optoelectronics, photovoltaics and spintronics. Research papers and reviews on the basics of ALD growth are also included, reflecting a growing interest in precursor chemistry and growth

  13. Multi-colored layers for visualizing aerodynamic flow effects

    NASA Technical Reports Server (NTRS)

    Jensen, Ronald N. (Inventor)

    1991-01-01

    A method is provided for visualizing aerodynamic flow effects on a test surface. First, discrete quantities of a sublimating chemical such as naphthalene are distinctively colored via appropriate dyes or paints. Next, a uniform layer of the sublimating chemical having a particular color is applied to the test surface. This layer is covered with a second uniform layer of a different colored sublimating chemical, and so on until a composite of multi-colored layers is formed having a discrete thickness. Friction caused by an airflow results in the distinctly colored layers being removed in proportion to such aerodynamic flow characteristics as velocity and temperature, resulting in a multi-colored portrait which approximates the air flow on the underlying test surface.

  14. Evaluating CMIP5 models using AIRS tropospheric air temperature and specific humidity climatology

    NASA Astrophysics Data System (ADS)

    Tian, Baijun; Fetzer, Eric J.; Kahn, Brian H.; Teixeira, Joao; Manning, Evan; Hearty, Thomas

    2013-01-01

    This paper documents the climatological mean features of the Atmospheric Infrared Sounder (AIRS) monthly mean tropospheric air temperature (ta, K) and specific humidity (hus, kg/kg) products as part of the Obs4MIPs project and compares them to those from NASA's Modern Era Retrospective analysis for Research and Applications (MERRA) for validation and 16 models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) for CMIP5 model evaluation. MERRA is warmer than AIRS in the free troposphere but colder in the boundary layer with differences typically less than 1 K. MERRA is also drier (~10%) than AIRS in the tropical boundary layer but wetter (~30%) in the tropical free troposphere and the extratropical troposphere. In particular, the large MERRA-AIRS specific humidity differences are mainly located in the deep convective cloudy regions indicating that the low sampling of AIRS in the cloudy regions may be the main reason for these differences. In comparison to AIRS and MERRA, the sixteen CMIP5 models can generally reproduce the climatological features of tropospheric air temperature and specific humidity well, but several noticeable biases exist. The models have a tropospheric cold bias (around 2 K), especially in the extratropical upper troposphere, and a double-ITCZ problem in the troposphere from 1000 hPa to 300 hPa, especially in the tropical Pacific. The upper-tropospheric cold bias exists in the most (13 of 16) models, and the double-ITCZ bias is found in all 16 CMIP5 models. Both biases are independent of the reference dataset used (AIRS or MERRA).

  15. Air cushioning in droplet impact. II. Experimental characterization of the air film evolution

    NASA Astrophysics Data System (ADS)

    de Ruiter, Jolet; van den Ende, Dirk; Mugele, Frieder

    2015-01-01

    A liquid drop approaching a solid surface deforms substantially under the influence of the ambient air which needs to be squeezed out before the liquid can actually touch the solid. We use nanometer- and microsecond-resolved dual wavelength interferometry described in Part I (also published in this issue) to reveal the complex spatial and temporal evolution of the squeezed air layer. In low-velocity droplet impact, i.e., We numbers of order unity, the confined air layer below the droplet develops two local minima in thickness. We quantitatively measure the evolution of the droplet bottom interface and find that surface tension determines the air film thickness below the first kink, after which fluid is diverted outward to form a second even sharper kink. Depending on We, one of the two kinks approaches the surface more closely forming liquid-solid contact. The early time spreading of liquid-solid contact is controlled by the capillary driving force and the inertia of the liquid. The cushioned air film geometry, i.e., a flat micrometer-thin gap, induces an increase of the spreading velocity; the contact area first spreads over the cushioned region, only then followed by radial spreading. This spreading mechanism can lead to the entrapment of one or more air bubbles.

  16. Cumulus cloud venting of mixed layer ozone

    NASA Technical Reports Server (NTRS)

    Ching, J. K. S.; Shipley, S. T.; Browell, E. V.; Brewer, D. A.

    1985-01-01

    Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and aerosols occurs between the mixed layer and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and aerosol backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-height analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed layer and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon.

  17. Evaluation of filters for removal of bacteriophages from air.

    PubMed

    Washam, C J; Black, C H; Sandine, W E; Elliker, P R

    1966-07-01

    Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft(3)/min) and high flow rate (10 to 25 ft(3)/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.543 to 99.83% efficient, whereas cotton (five layers), fiberglass medium (three layers), and the commercial absolute filter were at least 99.900, 99.999, and 99.999 efficient, respectively. Glass wool and cotton were not used under higher air-flow conditions because they were difficult to assemble in leak-tight filters. The commercial absolute filter and fiberglass medium (three layers) were at least 99.990 and 99.999% efficient, respectively, under the higher air flow conditions. A stainless-steel filter of simple design and fitted with three layers of fiberglass medium was found to be greater than 99.999% efficient in removing high concentrations (20,000 to 70,000 plaque-forming units per cubic foot) of aerosolized bacteriophages from air moving at a low flow rate (1 ft(3)/min). Use of this filter on pressure-vacuum tanks in the fermentation industry is suggested. Several other uses of such a filter are proposed.

  18. Evaluation of Filters for Removal of Bacteriophages from Air1

    PubMed Central

    Washam, C. J.; Black, C. H.; Sandine, W. E.; Elliker, P. R.

    1966-01-01

    Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft3/min) and high flow rate (10 to 25 ft3/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.543 to 99.83% efficient, whereas cotton (five layers), fiberglass medium (three layers), and the commercial absolute filter were at least 99.900, 99.999, and 99.999 efficient, respectively. Glass wool and cotton were not used under higher air-flow conditions because they were difficult to assemble in leak-tight filters. The commercial absolute filter and fiberglass medium (three layers) were at least 99.990 and 99.999% efficient, respectively, under the higher air flow conditions. A stainless-steel filter of simple design and fitted with three layers of fiberglass medium was found to be greater than 99.999% efficient in removing high concentrations (20,000 to 70,000 plaque-forming units per cubic foot) of aerosolized bacteriophages from air moving at a low flow rate (1 ft3/min). Use of this filter on pressure-vacuum tanks in the fermentation industry is suggested. Several other uses of such a filter are proposed. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:5927020

  19. Ruthenium / aerogel nanocomposits via Atomic Layer Deposition

    SciTech Connect

    Biener, J; Baumann, T F; Wang, Y; Nelson, E J; Kucheyev, S O; Hamza, A V; Kemell, M; Ritala, M; Leskela, M

    2006-08-28

    We present a general approach to prepare metal/aerogel nanocomposites via template directed atomic layer deposition (ALD). In particular, we used a Ru ALD process consisting of alternating exposures to bis(cyclopentadienyl)ruthenium (RuCp{sub 2}) and air at 350 C to deposit metallic Ru nanoparticles on the internal surfaces of carbon and silica aerogels. The process does not affect the morphology of the aerogel template and offers excellent control over metal loading by simply adjusting the number of ALD cycles. We also discuss the limitations of our ALD approach, and suggest ways to overcome these.

  20. Boundary layer simulator improvement

    NASA Technical Reports Server (NTRS)

    Praharaj, Sarat C.; Schmitz, Craig P.; Nouri, Joseph A.

    1989-01-01

    Boundary Layer Integral Matrix Procedure (BLIMPJ) has been identified by the propulsion community as the rigorous boundary layer program in connection with the existing JANNAF reference programs. The improvements made to BLIMPJ and described herein have potential applications in the design of the future Orbit Transfer Vehicle engines. The turbulence model is validated to include the effects of wall roughness and a way is devised to treat multiple smooth-rough surfaces. A prediction of relaminarization regions is examined as is the combined effects of wall cooling and surface roughness on relaminarization. A turbulence model to represent the effects of constant condensed phase loading is given. A procedure is described for thrust decrement calculation in thick boundary layers by coupling the T-D Kinetics Program and BLIMPJ and a way is provided for thrust loss optimization. Potential experimental studies in rocket nozzles are identified along with the required instrumentation to provide accurate measurements in support of the presented new analytical models.

  1. North Polar Layers

    NASA Technical Reports Server (NTRS)

    2004-01-01

    3 December 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an exposure of finely-detailed layers in the martian north polar region. The polar ice cap, which is made up of frozen water (whereas the south polar cap is mostly frozen carbon dioxide), is underlain by a thick sequence of layers. Some have speculated that these layers may record the history of changes in martian climate during the past few hundreds of millions of years. This picture is located near 86.0oN, 30.2oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  2. MHD turbulent mixing layers

    SciTech Connect

    Esquivel, A.; Lazarian, A.; Benjamin, R.A.; Cho, J.; Leitner, S.N.

    2005-09-28

    Turbulent mixing layers have been proposed to explain observations of line ratios of highly ionized elements in the interstellar medium. We present preliminary results of numerical simulations of turbulent mixing layers in a magnetized medium. We developed a MHD code with radiative cooling. The magnetic field is expected to be a controlling factor by suppressing instabilities that lead to the turbulent mixing. Our results suggest that the difference in turbulent mixing in the unmagnetized case as compared to the case of a weak magnetic field, {beta} = Pgas/Pmag {approx} 10, is insignificant. With a more thorough exploration of parameter space, this work will provide more reliable diagnostics of turbulent mixing layers than those available today.

  3. South Polar Layers

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-516, 17 October 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded, stair-stepped layers in the south polar region of Mars. These layers have been considered, for the past three decades, to consist of a mixture of dust and ice. The Mars Polar Lander (MPL) mission was designed to test this hypothesis. However, sadly, MPL was lost during descent in December 1999. This exposure of south polar layered material is located near 86.3oS, 187.7oW. The image covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the upper left.

  4. Layered Systems Engineering Engines

    NASA Technical Reports Server (NTRS)

    Breidenthal, Julian C.; Overman, Marvin J.

    2009-01-01

    A notation is described for depicting the relationships between multiple, contemporaneous systems engineering efforts undertaken within a multi-layer system-of-systems hierarchy. We combined the concepts of remoteness of activity from the end customer, depiction of activity on a timeline, and data flow to create a new kind of diagram which we call a "Layered Vee Diagram." This notation is an advance over previous notations because it is able to be simultaneously precise about activity, level of granularity, product exchanges, and timing; these advances provide systems engineering managers a significantly improved ability to express and understand the relationships between many systems engineering efforts. Using the new notation, we obtain a key insight into the relationship between project duration and the strategy selected for chaining the systems engineering effort between layers, as well as insights into the costs, opportunities, and risks associated with alternate chaining strategies.

  5. Oscillatory and nonoscillatory behavior of a simple model for cool flames, Sal'nikov's reaction, P{yields}A {yields}B, occurring in a spherical batch reactor with varying intensities of natural convection

    SciTech Connect

    Campbell, A.N.; Cardoso, S.S.S.; Hayhurst, A.N.

    2008-07-15

    When cool flames, or indeed any exothermic chemical reaction, occur in a fluid inside an unstirred vessel, the heat from the reaction often induces temperature gradients and consequently motion, i.e., natural convection. The intensity of the resulting flow is governed by the Rayleigh number (Ra). This work simulates numerically the behavior of Sal'nikov's reaction, P{yields} A{yields}B, under the influence of natural convection in an unstirred spherical reactor. This reaction is the simplest to exhibit the thermokinetic oscillations characterizing cool flames. The behavior of this system can be represented on a three-dimensional regime diagram, whose axes are ratios of the characteristic timescales ({tau}) for chemical reaction, diffusion (of both heat and mass), and natural convection. Previous work has identified a region of oscillations on this diagram in the purely diffusive limit, when Ra=0. This work extends this analysis to the general 3D space, where diffusion and natural convection are both important. A region in which oscillations are observed has been found for fixed values of the first-order rate constants for Sal'nikov's reaction. There is a distinct change in the shape of the region of oscillations around the critical value of Ra{proportional_to}500, when natural convection becomes important. When diffusion dominates transport (Ra<500), the boundaries between oscillatory and nonoscillatory solutions are largely independent of the ratio of timescales {tau}{sub step}2/{tau}{sub convection} and agree well with the values found previously in the purely diffusive limit. When natural convection is important (Ra>500), the oscillations occur over a wider range of parameters than is the case for a diffusive system. The presence of natural convection also leads to various, more complex behaviors than are seen in the diffusive or well-mixed limits. A region in the regime diagram was found where the oscillations in temperature and the concentration of A have

  6. Indoor Air Pollution

    MedlinePlus

    ... is known as sick building syndrome. Usually indoor air quality problems only cause discomfort. Most people feel better ... and getting rid of pollutants can improve the quality of your indoor air. Environmental Protection Agency

  7. Lead (Pb) Air Pollution

    MedlinePlus

    ... and 2014. In 2008, EPA significantly strengthened the air quality standards for lead to provide health protection for ... time? Setting and Reviewing Standards What are lead air quality standards? How are they developed and reviewed? What ...

  8. Transforming air quality management

    SciTech Connect

    Janet McCabe

    2005-04-01

    Earlier this year, the Clean Air Act Advisory Committee submitted to EPA 38 recommendations intended to improve air quality management in the United States. This article summarizes the evaluation process leading up to the Committee's recommendations. 3 refs., 2 figs.

  9. National Air Toxics Assessment

    EPA Pesticide Factsheets

    NATA is an ongoing comprehensive evaluation of air toxics in the U.S. As a screening tool, it helps air agencies prioritize pollutants, emission sources and locations of interest for further study to gain a better understanding of risks.

  10. Airing It Out.

    ERIC Educational Resources Information Center

    Fitzemeyer, Ted

    2000-01-01

    Discusses how proper maintenance can help schools eliminate sources contributing to poor air quality. Maintaining heating and air conditioning units, investigating bacterial breeding grounds, fixing leaking boilers, and adhering to ventilation codes and standards are discussed. (GR)

  11. Air Quality Analysis

    EPA Pesticide Factsheets

    This site provides information for air quality data analysts inside and outside EPA. Much of the information is in the form of documented analyses that support the review of the national air qualiyt standards.

  12. Controlling Indoor Air Pollution.

    ERIC Educational Resources Information Center

    Nero, Anthony V, Jr.

    1988-01-01

    Discusses the health risks posed by indoor air pollutants, such as airborne combustion products, toxic chemicals, and radioactivity. Questions as to how indoor air might be regulated. Calls for new approaches to environmental protection. (TW)

  13. Air Data - Concentration Map

    EPA Pesticide Factsheets

    Make a map of daily concentrations over several days. The daily air quality can be displayed in terms of the Air Quality Index or in concentration ranges for certain PM species like organic carbon, nitrates, and sulfates.

  14. Possibilities for drag reduction by boundary layer control

    NASA Technical Reports Server (NTRS)

    Naiman, I.

    1946-01-01

    The mechanics of laminar boundary layer transition are reviewed. Drag possibilities for boundary layer control are analyzed using assumed conditions of transition Reynolds number, inlet loss, number of slots, blower efficiency, and duct losses. Although the results of such analysis are highly favorable, those obtained by experimental investigations yield conflicting results, showing only small gains, and sometimes losses. Reduction of this data indicates that there is a lower limit to the quantity of air which must be removed at the slot in order to stabilize the laminar flow. The removal of insufficient air permits transition to occur while the removal of excessive amounts of air results in high power costs, with a net drag increases. With the estimated value of flow coefficient and duct losses equal to half the dynamic pressure, drag reductions of 50% may be obtained; with twice this flow coefficient, the drag saving is reduced to 25%.

  15. Sedimentary Rock Layers

    NASA Technical Reports Server (NTRS)

    2004-01-01

    27 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers of sedimentary rock in a crater in western Arabia Terra. Layered rock records the history of a place, but an orbiter image alone cannot tell the entire story. These materials record some past episodes of deposition of fine-grained material in an impact crater that is much larger than the image shown here. The picture is located near 3.4oN, 358.7oW, and covers an area 3 km (1.9 mi.) wide. Sunlight illuminates the scene from the lower left.

  16. Layers Inside 'Endurance'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This view of rock layers exposed in the upper portion of the inner slope of 'Endurance Crater' was captured by the navigation camera on NASA's Mars Exploration Rover Opportunity from the rover's position inside the crater during Opportunity's 134th sol on June 9, 2004. Scientists and engineers are assessing possible targets and routes among these rocks. The view is looking down into the crater, so the layers at the top of the image lie lower in the crater than the rocks in the foreground.

  17. Layered semiconductor neutron detectors

    DOEpatents

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  18. Boundary Layer Control for Hypersonic Airbreathing Vehicles

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; Nowak, Robert J.; Horvath, Thomas J.

    2004-01-01

    Active and passive methods for tripping hypersonic boundary layers have been examined in NASA Langley Research Center wind tunnels using a Hyper-X model. This investigation assessed several concepts for forcing transition, including passive discrete roughness elements and active mass addition (or blowing), in the 20-Inch Mach 6 Air and the 31-Inch Mach 10 Air Tunnels. Heat transfer distributions obtained via phosphor thermography, shock system details, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. The comparisons between the active and passive methods for boundary layer control were conducted at test conditions that nearly match the Hyper-X nominal Mach 7 flight test-point of an angle-of-attack of 2-deg and length Reynolds number of 5.6 million. For passive roughness, the primary parametric variation was a range of trip heights within the calculated boundary layer thickness for several trip concepts. The passive roughness study resulted in a swept ramp configuration, scaled to be roughly 0.6 of the calculated boundary layer thickness, being selected for the Mach 7 flight vehicle. For the active blowing study, the manifold pressure was systematically varied (while monitoring the mass flow) for each configuration to determine the jet penetration height, with schlieren, and transition movement, with the phosphor system, for comparison to the passive results. All the blowing concepts tested, which included various rows of sonic orifices (holes), two- and three-dimensional slots, and random porosity, provided transition onset near the trip location with manifold stagnation pressures on the order of 40 times the model surface static pressure, which is adequate to ensure sonic jets. The present results indicate that the jet penetration height for blowing was roughly half the height required with passive roughness elements for an equivalent amount of transition movement.

  19. Planetary Boundary Layer from AERI and MPL

    DOE Data Explorer

    Sawyer, Virginia

    2014-02-13

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  20. Dense gas boundary layer experiments: Visualization, pressure measurements, concentration evaluation

    SciTech Connect

    Reichenbach, H.; Neuwald, P.; Kuhl, A.L.

    1992-11-01

    This technical report describes methods that were applied to investigate turbulent boundary layers generated by inviscid, baroclinic effects. The Cranz-Schardin 24-sparks camera was used to visualize the interactions of a planar shock wave with a Freon R12-layer. The shock propagates more slowly in the Freon layer than in air because of its smaller sound speed. This causes the shock front to be curved and to be reflected between the wall and the layer interface. As a consequence of the reflection process, a series of compression and expansion waves radiate from the layer. Large fluctuations in the streamwise velocity and in pressure develop for about 1 ms. These waves strongly perturb the interface shear layer, which rapidly transitions to a turbulent boundary flow. Pressure measurements showed that the fluctuations in the Freon layer reach a peak pressure 4 times higher than in the turbulent boundary flow. To characterize the preshock Freon boundary layer, concentration measurements were performed with a differential interferometry technique. The refraction index of Freon R12 is so high that Mach-Zehnder interferometry was not successful in these experiments. The evaluation of the concentration profile is described here in detail. Method and results of corresponding LDV measurements under the same conditions are presented in a different report, EMI Report T 9/92. The authors plan to continue the dense gas layer investigations with the gas combination helium/Freon.

  1. BamI, KpnI, and SalI restriction enzyme maps of the DNAs of herpes simplex virus strains Justin and F: occurrence of heterogeneities in defined regions of the viral DNA.

    PubMed Central

    Locker, H; Frenkel, N

    1979-01-01

    We present the locations of the cleavage sites for the BamI, KpnI, and SalI restriction endonucleases within the DNA molecules of herpes simplex virus type 1 (HSV-1) strains Justin and F. These restriction enzymes cleave the HSV-1 DNA at many sites, producing relatively small fragments which should prove useful in future studies of HSV-1 gene structure and function. The mapping data revealed the occurrence of heterogeneity within three regions of the viral genome including (i) the region spanning map coordinates 0.74--0.76, (ii) the ends of the large (L) DNA component, and (iii) the junction between the large (L) and the small (S) components. The heterogeneity in the ends of L and the S-L junctions of HSV-1 (Justin) and HSV-1 (F) DNAs was grossly similar to that previously reported to occur in the ends of L and the S-L junctions of the HSV-1 (KOS) DNA (M. J. Wagner and W. C. Summers, J. Virol. 27:374--387, 1978). Thus, cleavage of these regions with restriction endonucleases yielded sets of minor fragments differing in size by constant increments. However, the various strains of HSV-1 differed with respect to the numbers, size increments, and relative molarities of the various minor fragments, suggesting that the parameters of the heterogeneity are inherited in the structural makeup of the HSV-1 genome. The strain dependence of the pattern of heterogeneity can be most easily explained in terms of variable sizes of the terminally reiterated a sequence, contained in the DNA molecules of these three strains of HSV-1. Images PMID:228068

  2. Into Thin Air.

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2001-01-01

    Shows how schools are working to avoid the types of equipment, supplies, and maintenance practices that harm indoor air quality. Simple steps to maintaining a cleaner indoor air environment are highlighted as are steps to reducing the problem air quality and the occurrence of asthma. (GR)

  3. Indoor Air Quality Manual.

    ERIC Educational Resources Information Center

    Baldwin Union Free School District, NY.

    This manual identifies ways to improve a school's indoor air quality (IAQ) and discusses practical actions that can be carried out by school staff in managing air quality. The manual includes discussions of the many sources contributing to school indoor air pollution and the preventive planning for each including renovation and repair work,…

  4. Air Sensor Guidebook

    EPA Science Inventory

    This Air Sensor Guidebook has been developed by the U.S. EPA to assist those interested in potentially using lower cost air quality sensor technologies for air quality measurements. Its development was in direct response to a request for such a document following a recent scienti...

  5. Modelling Hot Air Balloons.

    ERIC Educational Resources Information Center

    Brimicombe, M. W.

    1991-01-01

    A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

  6. Air Pollution Training Programs.

    ERIC Educational Resources Information Center

    Public Health Service (DHEW), Rockville, MD.

    This catalog lists the universities, both supported and not supported by the Division of Air Pollution, which offer graduate programs in the field of air pollution. The catalog briefly describes the programs and their entrance requirements, the requirements, qualifications and terms of special fellowships offered by the Division of Air Pollution.…

  7. Effect of particle settling on lidar profiles of long-range transported Saharan aerosols

    NASA Astrophysics Data System (ADS)

    Gasteiger, Josef; Groß, Silke

    2016-04-01

    A large amount of desert aerosol is transported in the Saharan Air Layer (SAL) westwards from Africa over the Atlantic Ocean. Lidar profiles of transported Saharan aerosol may contain some information about the vertically-resolved aerosol microphysics that could be used to characterize processes that affected the measured aerosol during transport. We present modelled lidar profiles of long-range transported Saharan aerosol assuming that initially the SAL is well-mixed and that there is no vertical mixing of air within the SAL as soon as it reaches the Atlantic. We consider Stokes gravitational settling of aerosol particles over the ocean. The lidar profiles are calculated using optical models for irregularly-shaped mineral dust particles assuming settling-induced particle removal as function of distance from the SAL top. Within the SAL we find a decrease of both the backscatter coefficients and the linear depolarization ratios with decreasing distance from the SAL top. For example, the linear depolarization ratio at a wavelength of 532nm decreases from 0.289 at 1000m to 0.256 at 200m and 0.215 at 100m below SAL top. We compare the modelled backscatter coefficients and linear depolarization ratios to ground-based lidar measurements performed during the SALTRACE field campaign in Barbados (Caribbean) and find agreement within the estimated uncertainties. We discuss the uncertainties of our modeling approach in our presentation. Assumed mineral dust particle shapes, assumed particle mixture properties, and assumptions about processes in the SAL over the continent and the ocean are important aspects to be considered. Uncertainties are relevant for the potential of lidar measurements of transported Saharan dust to learn something about processes occuring in the SAL during long-range transport. We also compare our modeling results to modeling results previously published in the literature.

  8. Teaching the Double Layer.

    ERIC Educational Resources Information Center

    Bockris, J. O'M.

    1983-01-01

    Suggests various methods for teaching the double layer in electrochemistry courses. Topics addressed include measuring change in absolute potential difference (PD) at interphase, conventional electrode potential scale, analyzing absolute PD, metal-metal and overlap electron PDs, accumulation of material at interphase, thermodynamics of electrified…

  9. Layer-Cake Earth

    ERIC Educational Resources Information Center

    Tedford, Rebecca; Warny, Sophie

    2006-01-01

    In this article, the authors offer a safe, fun, effective way to introduce geology concepts to elementary school children of all ages: "coring" layer cakes. This activity introduces the concepts and challenges that geologists face and at the same time strengthens students' inferential, observational, and problem-solving skills. It also addresses…

  10. MITRE sensor layer prototype

    NASA Astrophysics Data System (ADS)

    Duff, Francis; McGarry, Donald; Zasada, David; Foote, Scott

    2009-05-01

    The MITRE Sensor Layer Prototype is an initial design effort to enable every sensor to help create new capabilities through collaborative data sharing. By making both upstream (raw) and downstream (processed) sensor data visible, users can access the specific level, type, and quantities of data needed to create new data products that were never anticipated by the original designers of the individual sensors. The major characteristic that sets sensor data services apart from typical enterprise services is the volume (on the order of multiple terabytes) of raw data that can be generated by most sensors. Traditional tightly coupled processing approaches extract pre-determined information from the incoming raw sensor data, format it, and send it to predetermined users. The community is rapidly reaching the conclusion that tightly coupled sensor processing loses too much potentially critical information.1 Hence upstream (raw and partially processed) data must be extracted, rapidly archived, and advertised to the enterprise for unanticipated uses. The authors believe layered sensing net-centric integration can be achieved through a standardize-encapsulate-syndicateaggregate- manipulate-process paradigm. The Sensor Layer Prototype's technical approach focuses on implementing this proof of concept framework to make sensor data visible, accessible and useful to the enterprise. To achieve this, a "raw" data tap between physical transducers associated with sensor arrays and the embedded sensor signal processing hardware and software has been exploited. Second, we encapsulate and expose both raw and partially processed data to the enterprise within the context of a service-oriented architecture. Third, we advertise the presence of multiple types, and multiple layers of data through geographic-enabled Really Simple Syndication (GeoRSS) services. These GeoRSS feeds are aggregated, manipulated, and filtered by a feed aggregator. After filtering these feeds to bring just the type

  11. A New Technique for Sampling Firn Air

    NASA Astrophysics Data System (ADS)

    Perron, F. E.; Dibb, J. E.; Albert, M. R.

    2004-12-01

    The discovery and subsequent interest in photochemical interactions between the polar snowpack and the atmosphere has spawned interest in reliable methods of measuring chemical concentrations in interstitial air. Consistent sampling of the interstitial air in the snowpack had been problematic due to great chemical differences possible from sampling different layers in the snow and the difficulties in acquiring a sample that could serve multiple investigators at the same time. This paper describes a new air sampling device that was developed to solve many of the sampling problems. This new system allows multiple simultaneous chemical analysis of air contained in the pore spaces of the arctic snowpack at unlimited increments from depths of 0 to 150 cm. The three major components are a 4 ft diameter highly UV transmittent acrylic "hood" with a 10 cm rim, a 10 cm diameter casing barrel, and an air probe head. These components operate along with a variety of sub-components that supplement the sampling process. The technique provides for a common sample collection, use for a variety of gases to be sampled, it eliminates short circuit air sampling, provides undisturbed snow for in-situ sampling at multiple sample depths in the same location. The design is discussed and possible extension as a platform for other sensors is described.

  12. A review on air cathodes for zinc-air fuel cells

    NASA Astrophysics Data System (ADS)

    Neburchilov, Vladimir; Wang, Haijiang; Martin, Jonathan J.; Qu, Wei

    This paper reviews the compositions, design and methods of fabrication of air cathodes for alkali zinc-air fuel cells (ZAFCs), one of the few successfully commercialized fuel cells. The more promising compositions for air cathodes are based on individual oxides, or mixtures of such, with a spinel, perovskite, or pyrochlore structure: MnO 2, Ag, Co 3O 4, La 2O 3, LaNiO 3, NiCo 2O 4, LaMnO 3, LaNiO 3, etc. These compositions provide the optimal balance of ORR activity and chemical stability in an alkali electrolyte. The sol-gel and reverse micelle methods supply the most uniform distribution of the catalyst on carbon and the highest catalyst BET surface area. It is shown that the design of the air cathode, including types of carbon black, binding agents, current collectors, Teflon membranes, thermal treatment of the GDL, and catalyst layers, has a strong effect on performance.

  13. Methods to protect and recover work function of air exposed transition metal oxide thin films

    NASA Astrophysics Data System (ADS)

    Irfan, Irfan; Wang, Chenggong; Turinske, Alexander J.; Gao, Yongli

    2012-09-01

    Insertion of high work function (WF) transition metal oxide (TMO) layers between the anode and the hole transport layer is established to substantially enhance the performance of organic light emitting diodes (OLED). The high WF of transition metal oxide layer has been demonstrated to be the most crucial for the enhancement. The WF of a TMO layer decreases substantially with air exposure, and noticeably by the ambient even inside a low vacuum system. In the present work we discuss various methods to protect and recover the high WF after a TMO thin film has been exposed to air. We report covering a thin organic layer on top of MoOx to protect the high work function. We found that a thin layer of 1-2 nm organic layer was sufficient to protect the work function of MoOx thin film underneath. We further report methods to recover already decreased TMO WF due to air exposure. We performed oxygen plasma cleaning of air exposed MoOx film and found out that oxygen plasma could substantially recover the WF of as deposited MoOx film. We also performed annealing of air exposed MoOx film inside an ultra high vacuum system and observed a thin layer of oxygenrich adsorbate layer, which desorbed upon annealing that in turn substantially recovered the MoOx WF. We discuss the vacuum annealing and the effect of resulting surface on the interface energy level alignment.

  14. Air Conditioning Does Reduce Air Pollution Indoors

    ERIC Educational Resources Information Center

    Healy, Bud

    1970-01-01

    Report of the winter meeting of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Subjects covered are--(1) title subject, (2) predictions for the human habitat in 1994, (3) fans, and (4) fire safety in buildings. (JW)

  15. Air Parity: Re-Discovering Contested Air Operations

    DTIC Science & Technology

    2016-06-01

    AIR PARITY: RE-DISCOVERING CONTESTED AIR OPERATIONS BY CHRISTOPHER LAZIDIS A THESIS PRESENTED TO THE FACULTY OF...THE SCHOOL OF ADVANCED AIR AND SPACE STUDIES FOR COMPLETION OF GRADUATION REQUIREMENTS SCHOOL OF ADVANCED AIR AND SPACE STUDIES AIR ...UNIVERSITY MAXWELL AIR FORCE BASE, ALABAMA JUNE 2016 DISTRIBUTION A. Approved for public release: distribution unlimited ii APPROVAL The

  16. Tropical storm redistribution of Saharan dust to the upper troposphere and ocean surface

    NASA Astrophysics Data System (ADS)

    Herbener, Stephen R.; Saleeby, Stephen M.; Heever, Susan C.; Twohy, Cynthia H.

    2016-10-01

    As a tropical cyclone traverses the Saharan Air Layer (SAL), the storm will spatially redistribute the dust from the SAL. Dust deposited on the surface may affect ocean fertilization, and dust transported to the upper levels of the troposphere may impact radiative forcing. This study explores the relative amounts of dust that are vertically redistributed when a tropical cyclone crosses the SAL. The Regional Atmospheric Modeling System (RAMS) was configured to simulate the passage of Tropical Storm Debby (2006) through the SAL. A dust mass budget approach has been applied, enabled by a novel dust mass tracking capability of the model, to determine the amounts of dust deposited on the ocean surface and transferred aloft. The mass of dust removed to the ocean surface was predicted to be nearly 2 orders of magnitude greater than the amount of dust transported to the upper troposphere.

  17. Air Conditioner/Dehumidifier

    NASA Technical Reports Server (NTRS)

    1986-01-01

    An ordinary air conditioner in a very humid environment must overcool the room air, then reheat it. Mr. Dinh, a former STAC associate, devised a heat pipe based humidifier under a NASA Contract. The system used heat pipes to precool the air; the air conditioner's cooling coil removes heat and humidity, then the heat pipes restore the overcooled air to a comfortable temperature. The heat pipes use no energy, and typical savings are from 15-20%. The Dinh Company also manufactures a "Z" coil, a retrofit cooling coil which may be installed on an existing heater/air conditioner. It will also provide free hot water. The company has also developed a photovoltaic air conditioner and solar powered water pump.

  18. Cluster analysis for description and characterization of boundary-layer eddies

    NASA Astrophysics Data System (ADS)

    Lennartz-Sassinek, Sabine; Liu, Shaofeng; Shao, Yaping

    2014-05-01

    Boundary-layer eddies play an important role in atmosphere and land-surface interactions. It is already known that near the surface many small eddies exist, which merge to form large eddies in the upper layers of the atmospheric boundary layer. However, it is not yet fully understood how these eddies organize themselves and how the organization can be best described. In this study, we present a new cluster analysis for description and characterization of boundary-layer eddies. Using this method, we group physical parameters in each air layer according to certain rules to connected clusters, each of which represents an eddy. The method is applied to the simulations of a coupled large-eddy atmosphere and land-surface model (LES-ALM). We present how the eddies are determined based on the different physical parameters for different air layers, the size distribution of the eddies within an air layer and how the results depend on the chosen physical parameter such as temperature, vertical temperature flux, moisture, vertical moisture flux and vertical wind. This analysis will help to better understand how information is transported through the different air layers and thus the role eddies play in the land-surface atmosphere interactions.

  19. Reactivity and applications of layered silicates and layered double hydroxides.

    PubMed

    Selvam, Thangaraj; Inayat, Alexandra; Schwieger, Wilhelm

    2014-07-21

    Layered materials, such as layered sodium silicates and layered double hydroxides (LDHs), are well-known for their remarkable adsorption, intercalation and swelling properties. Their tunable interlayers offer an interesting avenue for the fabrication of pillared nanoporous materials, organic-inorganic hybrid materials and catalysts or catalyst supports. This perspective article provides a summary of the reactivity and applications of layered materials including aluminium-free layered sodium silicates (kanemite, ilerite (RUB-18 or octosilicate) and magadiite) and layered double hydroxides (LDHs). Recent developments in the use of layered sodium silicates as precursors for the preparation of various porous, functional and catalytic materials including zeolites, mesoporous materials, pillared layered silicates, organic-inorganic nanocomposites and synthesis of highly dispersed nanoparticles supported on silica are reviewed in detail. Along this perspective, we have attempted to illustrate the reactivity and transformational potential of LDHs in order to deduce the main differences and similarities between these two types of layered materials.

  20. Health Effects of Air Pollution

    MedlinePlus

    ... Health effects of air pollution Health effects of air pollution Breathing air that is not clean can hurt ... important to know about the health effects that air pollution can have on you and others. Once you ...