30 CFR 7.101 - Surface temperature tests.

Code of Federal Regulations, 2011 CFR

2011-07-01

... in the application, § 7.97(a)(3). (iii) If a wet exhaust conditioner is used to cool the exhaust gas... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be..., by volume, of methane in the intake air mixture until all parts of the engine, exhaust coolant system...

30 CFR 7.101 - Surface temperature tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... in the application, § 7.97(a)(3). (iii) If a wet exhaust conditioner is used to cool the exhaust gas... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be..., by volume, of methane in the intake air mixture until all parts of the engine, exhaust coolant system...

30 CFR 7.101 - Surface temperature tests.

Code of Federal Regulations, 2012 CFR

2012-07-01

... in the application, § 7.97(a)(3). (iii) If a wet exhaust conditioner is used to cool the exhaust gas... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be..., by volume, of methane in the intake air mixture until all parts of the engine, exhaust coolant system...

Solar cycle activity and atmospheric dynamics revealed by Be-7

NASA Astrophysics Data System (ADS)

Kulan, A.; Aldahan, A.; Possnert, G.; Vintersved, I.

2003-04-01

In this study we present ^7Be and 137Cs concentrations in aerosols collected on surface air filters for the period 1972-2000 from three stations in Sweden covering latitudes 56^o to 70^o. The cosmogenic isotope ^7Be (T1/2 = 53.4 days) is produced by interaction of cosmic rays with the atmosphere. ^7Be is adsorbed onto aerosol particles after its formation, and removed from the atmosphere by both dry and wet deposition (atmospheric residence time of about one year). Maximum production of ^7Be occurs in the polar regions and the maximum deposition is found in the middle latitudes. After its production (mainly in the stratosphere) the ^7Be isotope is subjected to vertical and horizontal transport processes within the atmosphere and accordingly can act as a tracer of air mass origin and its approximate age. Furthermore, the production of cosmogenic isotopes is strongly influenced by the solar wind (solar activity, mainly energetic protons) and hence terrestrial records of ^7Be are directly reflecting the activity of the sun. Our ^7Be results reveal seasonal changes and together with the 137Cs records confirm a long-term transport and a strong coupling with air masses from middle and low latitudes. An apparent correlation between the 11-year solar cycle activity and ^7Be is found and we also observe that precipitation effectively depletes ^7Be from the atmosphere through washout of aerosols.

Estimation of the peak entrance surface air kerma for patients undergoing computed tomography-guided procedures.

PubMed

Avilés Lucas, P; Dance, D R; Castellano, I A; Vañó, E

2005-01-01

The purpose of this work was to develop a method for estimating the patient peak entrance surface air kerma from measurements using a pencil ionisation chamber on dosimetry phantoms exposed in a computed tomography (CT) scanner. The method described is especially relevant for CT fluoroscopy and CT perfusion procedures where the peak entrance surface air kerma is the risk-related quantity of primary concern. Pencil ionisation chamber measurements include scattered radiation, which is outside the primary radiation field, and that must be subtracted in order to derive the peak entrance surface air kerma. A Monte Carlo computer model has therefore been used to calculate correction factors, which may be applied to measurements of the CT dose index obtained using a pencil ionisation chamber in order to estimate the peak entrance surface air kerma. The calculations were made for beam widths of 5, 7, 10 and 20 mm, for seven positions of the phantom, and for the geometry of a GE HiSpeed CT/i scanner. The program was validated by comparing measurements and calculations of CTDI for various vertical positions of the phantom and by directly estimating the peak ESAK using the program. Both validations showed agreement within statistical uncertainties (standard deviation of 2.3% or less). For the GE machine, the correction factors vary by approximately 10% with slice width for a fixed phantom position, being largest for the 20 mm beam width, and at that beam width range from 0.87 when the phantom surface is at the isocentre to 1.23 when it is displaced vertically by 24 cm.

The Carbon Cycle Response to Two El Nino Types: Observational Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chylek, Petr; Tans, Pieter; Christy, John

Here, we analyze monthly tropical near surface air temperature and Mauna Loa Observatory carbon dioxide (CO 2) data within 1960-2016 to identify different carbon cycle responses for two El Nino types: El Ninos originating in the central tropical Pacific (CP El Nino) and El Ninos originating in the eastern tropical Pacific (EP El Nino). We find significant differences between the two types of El Nino events with respect to time delay of the CO 2 rise rate that follows the increase in tropical near surface air temperatures caused by El Nino events. The average time lag of the CP Elmore » Nino is 4.0±1.7 months, while the mean time lag of EP El Nino is found to be 8.5±2.3 months. The average lag of all considered 1960-2016 El Ninos is 5.2±2.7 months. In contrast the sensitivity of CO2 growth rate to tropical near surface air temperature increase is determined to be about the same for both El Nino types equal to 2.8±0.9 ppmyr -1K -1 (or 5.9±1.9 GtCyr -1K -1). Our results should be useful for the understanding of the carbon cycle and constraining it in climate models.« less

The Carbon Cycle Response to Two El Nino Types: Observational Study

DOE PAGES

Chylek, Petr; Tans, Pieter; Christy, John; ...

2017-11-22

Here, we analyze monthly tropical near surface air temperature and Mauna Loa Observatory carbon dioxide (CO 2) data within 1960-2016 to identify different carbon cycle responses for two El Nino types: El Ninos originating in the central tropical Pacific (CP El Nino) and El Ninos originating in the eastern tropical Pacific (EP El Nino). We find significant differences between the two types of El Nino events with respect to time delay of the CO 2 rise rate that follows the increase in tropical near surface air temperatures caused by El Nino events. The average time lag of the CP Elmore » Nino is 4.0±1.7 months, while the mean time lag of EP El Nino is found to be 8.5±2.3 months. The average lag of all considered 1960-2016 El Ninos is 5.2±2.7 months. In contrast the sensitivity of CO2 growth rate to tropical near surface air temperature increase is determined to be about the same for both El Nino types equal to 2.8±0.9 ppmyr -1K -1 (or 5.9±1.9 GtCyr -1K -1). Our results should be useful for the understanding of the carbon cycle and constraining it in climate models.« less

Experimental Investigations on Beamed Energy Aerospace Propulsion

DTIC Science & Technology

2012-01-01

the aluminum ―igniter‖ material greatly lowers the incident laser intensity and fluence required to trigger the optical air breakdown 7 . The geometry...sequence following laser-induced air -breakdown was lost. The pressure distribution across the under-surface of the shroud is displayed in Fig. 24, along...photograph of bifurcated air -breakdown geometry across inlet gap, and secondary breakdown on shroud under-surface. 37 Fig. 29 Run#21 – Measured

[Impacts of meteorological factors on atmospheric methane mole fractions in the background area of Yangtze River delta].

PubMed

Pu, Jing-Jiao; Xu, Hong-Hui; Gu, Jun-Qiang; Ma, Qian-Li; Fang, Shuang-Xi; Zhou, Ling-Xi

2013-03-01

Impacts of surface wind direction, surface wind speed, surface air temperature and sunshine hours on the CH4 concentration at Lin'an regional atmospheric background station were studied based on the results from Jan. 2009 to Dec. 2011. The results revealed that the diurnal variation of atmospheric CH4 concentration presented a single-peak curve at Lin'an regional background station. The diurnal amplitude varied from 19.0 x 10(-9) to 74.7 x 10(-9), with the lowest value observed in the afternoon and the highest at dawn. The monthly mean CH4 concentrations varied from 1955.7 x 10(-9) to 2036.2 x 10(-9), with the highest concentration observed in autumn and the lowest in spring. The wind directions NE-SSE could induce higher CH4 concentrations while SW-NNW wind directions had negative effects on the observed results. The CH4 concentration turned out to be lower with higher surface wind speed. With the increase of surface air temperature or sunshine hours, the CH4 concentration went up first till reaching a peak, and then decreased.

Near-surface temperature inversion during summer at Summit, Greenland, and its relation to MODIS-derived surface temperatures

NASA Astrophysics Data System (ADS)

Adolph, Alden C.; Albert, Mary R.; Hall, Dorothy K.

2018-03-01

As rapid warming of the Arctic occurs, it is imperative that climate indicators such as temperature be monitored over large areas to understand and predict the effects of climate changes. Temperatures are traditionally tracked using in situ 2 m air temperatures and can also be assessed using remote sensing techniques. Remote sensing is especially valuable over the Greenland Ice Sheet, where few ground-based air temperature measurements exist. Because of the presence of surface-based temperature inversions in ice-covered areas, differences between 2 m air temperature and the temperature of the actual snow surface (referred to as skin temperature) can be significant and are particularly relevant when considering validation and application of remote sensing temperature data. We present results from a field campaign extending from 8 June to 18 July 2015, near Summit Station in Greenland, to study surface temperature using the following measurements: skin temperature measured by an infrared (IR) sensor, 2 m air temperature measured by a National Oceanic and Atmospheric Administration (NOAA) meteorological station, and a Moderate Resolution Imaging Spectroradiometer (MODIS) surface temperature product. Our data indicate that 2 m air temperature is often significantly higher than snow skin temperature measured in situ, and this finding may account for apparent biases in previous studies of MODIS products that used 2 m air temperature for validation. This inversion is present during our study period when incoming solar radiation and wind speed are both low. As compared to our in situ IR skin temperature measurements, after additional cloud masking, the MOD/MYD11 Collection 6 surface temperature standard product has an RMSE of 1.0 °C and a mean bias of -0.4 °C, spanning a range of temperatures from -35 to -5 °C (RMSE = 1.6 °C and mean bias = -0.7 °C prior to cloud masking). For our study area and time series, MODIS surface temperature products agree with skin surface temperatures better than previous studies indicated, especially at temperatures below -20 °C, where other studies found a significant cold bias. We show that the apparent cold bias present in other comparisons of 2 m air temperature and MODIS surface temperature may be a result of the near-surface temperature inversion. Further investigation of how in situ IR skin temperatures compare to MODIS surface temperature at lower temperatures (below -35 °C) is warranted to determine whether a cold bias exists for those temperatures.

BUFR TABLE A

Science.gov Websites

Surface data - sea 2 Vertical soundings (other than satellite) 3 Vertical soundings (satellite) 4 Single level upper-air data (other than satellite) 5 Single level upper-air data (satellite) 6 Radar data 7 tables, complete replacement or update 12 Surface data (satellite) 13 Forecasts 14 Warnings 15-19

Study of ⁷Be and ²¹⁰Pb as radiotracers of African intrusions in Malaga (Spain).

PubMed

Gordo, E; Liger, E; Dueñas, C; Fernández, M C; Cañete, S; Pérez, M

2015-10-01

The relationship between the particulate matter in the atmosphere of Malaga and the origin of air masses with special attention to African intrusions was analyzed. The concentrations of PM10 and the activities of some radionuclides ((7)Be and (210)Pb) as tracers of these intrusions are discussed. The origin of these radiotracers is completely different. (210)Pb is a good tracer of air masses traveling close to the ground and come from inland areas. On the other hand, the production of (7)Be is very low in the vicinity of the Earth's surface, and increases with altitude, making it a great tracer of stratospheric air masses in the troposphere. Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of (7)Be and (210)Pb in aerosols at Malaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2009-2011 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory. The average concentration values of (7)Be and (210)Pb over the 3-year period have been found to be 5.05 and 0.55 mBq m(-3), respectively, with mean aerosol mass concentration of 53.6 μg m(-3). Taking into account the outbreaks of the daily values limits of PM10 in the study period (2009-2011), the origin of air masses is studied to explain three different situations of both radionuclides (7)Be and (210)Pb: 1) high concentrations of (7)Be and low concentrations of (210)Pb; 2) high concentrations of (210)Pb and low concentrations of (7)Be and 3) high concentrations of (7)Be and (210)Pb. Copyright © 2015 Elsevier Ltd. All rights reserved.

Signature of a Sudden Stratospheric Warming in the near-ground 7Be flux.

NASA Astrophysics Data System (ADS)

Pacini, A. A.

2015-12-01

We present here a study of the impact of one Sudden Stratospheric Warming (SSW) upon the atmospheric vertical dynamics based on 7Be measurements in near ground air, using both numerical and conceptual. In late September 2002, an unprecedented SSW event occurred in the southern hemisphere (SH), causing changes in the tropospheric circulation, ozone depletion and weakening of the polar jet in the mesosphere. There is an observational evidence suggesting that anomalies in the stratosphere play an important role in driving tropospheric weather producing tropospheric changes that can persists for up to 60 days in NH and up to about 90 days in the SH, as observed after the 2002 SSW (Thompson et al., 2005). Radioactive environmental techniques for tracing large-scale air-mass transport have been applied in studies of atmospheric dynamics for decades and they are becoming more and more precise due to the improvement of the instrumental sensitivity and associated modeling. Temporal variations of the cosmogenic 7Be concentration in the near-surface atmosphere can provide information on the air mass dynamics, precipitation patterns, stratosphere-troposphere coupling and cosmic ray variations. The present study is based on an analysis of 7Be concentration measured in near-ground air in the city of Angra dos Reis, Rio de Janeiro state, Brazil between 1987 and 2009. Using a simplified tropospheric 7Be model deposition based on a two-layer transport model, Pacini (2011) reported that the occurrence of strong downward air flux leave an imprint of the 3D motion of air masses to the near-ground air 7Be data in the studied region. In this work, we have further developed the two-layer model by adding one more layer: the lower stratosphere (LS). In normal conditions, the contribution of the LS 7Be to the near-ground isotopic variability would be very small. On the other hand, stratospheric source can be crucial for the SSW event, indicating that a strong stratospheric air intrusion happened after the SSW and induced a downward flux of stratospheric aerosols from the LS to the ground level lasting several months after the SSW peak, showing that its tropospheric consequences can be much larger than it is usually considered.

Five-year microbiological monitoring of wards and operating theatres in southern Italy.

PubMed

La Fauci, V; Genovese, C; Facciolà, A; Palamara, M A R; Squeri, R

2017-06-01

Nosocomial infections are one of the greatest problems in public health. Several studies have highlighted the role played by the hospital environment as a possible source of transmission of nosocomial pathogens. A five-year monitoring of bacterial contamination on healthcare workers hands, surfaces most closely in contact with inpatient wards, operating theatres and "at rest" and "in use" operating theatre air samples. For the samples, we used sterile swabs, contact slides, manual API, and automated VITEK systems for identification. In the five-year period, a total of 9396 samples were collected and analysed. In ward patients, 4398 samplings were carried out with 4.7%, 9.4%, 7%, 10.8% and 7.9% positive results respectively from 2010 to 2014. For hands, 648 samplings were carried out, with a positivity of 40.74%. In operating theatres, 4188 samples were taken, with a positivity of 11.9%. Regarding air in empty and full theatres, 1962 samplings were carried out with a positivity rate equal to 31.9%. The monitoring showed a low rate of contamination with a progressive decrease in the fiveyear period on operating theatres surfaces and hands, while there was an increase in the surgical site wards and in the air of operating rooms. Our investigation has revealed the presence of pathogens on the assessed surfaces and the need for environmental monitoring, which can be a valuable tool for reducing contamination.

PubMed Central

Genovese, C.; Facciolà, A.; Palamara, M.A.R.; Squeri, R.

2017-01-01

Summary Introduction. Nosocomial infections are one of the greatest problems in public health. Several studies have highlighted the role played by the hospital environment as a possible source of transmission of nosocomial pathogens. Methods. A five-year monitoring of bacterial contamination on healthcare workers hands, surfaces most closely in contact with inpatient wards, operating theatres and "at rest" and "in use" operating theatre air samples. For the samples, we used sterile swabs, contact slides, manual API, and automated VITEK systems for identification. Results. In the five-year period, a total of 9396 samples were collected and analysed. In ward patients, 4398 samplings were carried out with 4.7%, 9.4%, 7%, 10.8% and 7.9% positive results respectively from 2010 to 2014. For hands, 648 samplings were carried out, with a positivity of 40.74%. In operating theatres, 4188 samples were taken, with a positivity of 11.9%. Regarding air in empty and full theatres, 1962 samplings were carried out with a positivity rate equal to 31.9%. The monitoring showed a low rate of contamination with a progressive decrease in the fiveyear period on operating theatres surfaces and hands, while there was an increase in the surgical site wards and in the air of operating rooms. Conclusions. Our investigation has revealed the presence of pathogens on the assessed surfaces and the need for environmental monitoring, which can be a valuable tool for reducing contamination. PMID:28900357

Identifying and forecasting deep stratospheric ozone intrusions over the western United States from space

NASA Astrophysics Data System (ADS)

Lin, M.; Fiore, A. M.; Horowitz, L. W.; Cooper, O. R.; Langford, A. O.; Pan, L.; Liu, X.; Reddy, P. J.

2012-12-01

Recent studies have shown that deep stratospheric ozone intrusions can episodically enhance ground-level ozone above the health-based standard over the western U.S. in spring. Advanced warning of incoming intrusions could be used by state agencies to inform the public about poor air quality days. Here we explore the potential for using total ozone retrievals (version 5.2, level 3) at twice daily near global coverage from the AIRS instrument aboard the NASA Aqua satellite to identify stratospheric intrusions and forecast the eventual surface destination of transported stratospheric ozone. The method involves the correlation of AIRS daily total ozone columns at each 1ox1o grid box ~1-3 days prior to stratospheric enhancements to daily maximum 8-hour average ozone at a selected surface site using datasets from April to June in 2003-2011. The surface stratospheric enhancements are estimated by the GFDL AM3 chemistry-climate model which includes full stratospheric and tropospheric chemistry and is nudged to reanalysis winds. Our earlier work shows that the model presents deep stratospheric intrusions over the Western U.S. consistently with observations from AIRS, surface networks, daily ozone sondes, and aircraft lidar available in spring of 2010 during the NOAA CalNex field campaign. For the 15 surface sites in the U.S. Mountain West considered, a correlation coefficient of 0.4-0.7 emerges with AIRS ozone columns over 30o-50oN latitudes and 125o-105oW longitudes - variability in the AIRS column within this spatial domain indicates incoming intrusions. For each "surface receptor site", the spatial domain can narrow to an area ~5ox5o northwest of the individual site, with the strong correlation (0.5-0.7) occurring when the AIRS data is lagged by 1 day from the AM3 stratospheric enhancements in surface air. The spatial pattern of correlations is consistent with our process-oriented understanding developed from case studies of extreme intrusions. Surface observations during these events show that the sites experiencing elevated ozone levels are typically located over the southeastern side of the enhanced ozone columns captured by AIRS ~12 hours to 1 day prior. This first scoping study suggests there is potential to use near-daily global coverage of ozone in total column or in UT/LS levels from the space-based instruments (e.g. AIRS, OMI, MLS) to serve as a qualitative early-warning indicator of incoming stratospheric intrusions with a lead time of ~1-3 days. There is more skill in ~12 hours to 1 day as to where the intrusion will reach the surface, particularly during the ENSO years (i.e. 2003, 2008, 2010, 2011) when deep intrusions are more likely to occur as compared to other years. These space-based ozone products can also provide some indication of whether a historic exceedance was caused by an intrusion.

Methane flux across the air-water interface - Air velocity effects

NASA Technical Reports Server (NTRS)

Sebacher, D. I.; Harriss, R. C.; Bartlett, K. B.

1983-01-01

Methane loss to the atmosphere from flooded wetlands is influenced by the degree of supersaturation and wind stress at the water surface. Measurements in freshwater ponds in the St. Marks Wildlife Refuge, Florida, demonstrated that for the combined variability of CH4 concentrations in surface water and air velocity over the water surface, CH4 flux varied from 0.01 to 1.22 g/sq m/day. The liquid exchange coefficient for a two-layer model of the gas-liquid interface was calculated as 1.7 cm/h for CH4 at air velocity of zero and as 1.1 + 1.2 v to the 1.96th power cm/h for air velocities from 1.4 to 3.5 m/s and water temperatures of 20 C.

Sea Ice Surface Temperature Product from the Moderate Resolution Imaging Spectroradiometer (MODIS)

NASA Technical Reports Server (NTRS)

Hall, Dorothy K.; Key, Jeffrey R.; Casey, Kimberly A.; Riggs, George A.; Cavalieri, Donald J.

2003-01-01

Global sea ice products are produced from the Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) on board both the Terra and Aqua satellites. Daily sea ice extent and ice-surface temperature (IST) products are available at 1- and 4-km resolution. Validation activities have been undertaken to assess the accuracy of the MODIS IST product at the South Pole station in Antarctica and in the Arctic Ocean using near-surface air-temperature data from a meteorological station and drifting buoys. Results from the study areas show that under clear skies, the MODIS ISTs are very close to those of the near-surface air temperatures with a bias of -1.1 and -1.2 K, and an uncertainty of 1.6 and 1.7 K, respectively. It is shown that the uncertainties would be reduced if the actual temperature of the ice surface were reported instead of the near-surface air temperature. It is not possible to get an accurate IST from MODIS in the presence of even very thin clouds or fog, however using both the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and the MODIS on the Aqua satellite, it may be possible to develop a relationship between MODIS-derived IST and ice temperature derived from the AMSR-E. Since the AMSR-E measurements are generally unaffected by cloud cover, they may be used to complement the MODIS IST measurements.

An improved diagnostic contact lens.

PubMed Central

Smith, R J

1979-01-01

Modification of a standard Goldmann goniolens by reducing the curvature of the contact surface to 8.5 mm radius of curvature (from the standard curvature of 7.4 mm) enabled gonioscopy to be carried out without the nuisance of air bubbles. Images PMID:465424

Regulation of Heat Exchange across the Hornbill Beak: Functional Similarities with Toucans?

PubMed

van de Ven, T M F N; Martin, R O; Vink, T J F; McKechnie, A E; Cunningham, S J

2016-01-01

Beaks are increasingly recognised as important contributors to avian thermoregulation. Several studies supporting Allen's rule demonstrate how beak size is under strong selection related to latitude and/or air temperature (Ta). Moreover, active regulation of heat transfer from the beak has recently been demonstrated in a toucan (Ramphastos toco, Ramphastidae), with the large beak acting as an important contributor to heat dissipation. We hypothesised that hornbills (Bucerotidae) likewise use their large beaks for non-evaporative heat dissipation, and used thermal imaging to quantify heat exchange over a range of air temperatures in eighteen desert-living Southern Yellow-billed Hornbills (Tockus leucomelas). We found that hornbills dissipate heat via the beak at air temperatures between 30.7°C and 41.4°C. The difference between beak surface and environmental temperatures abruptly increased when air temperature was within ~10°C below body temperature, indicating active regulation of heat loss. Maximum observed heat loss via the beak was 19.9% of total non-evaporative heat loss across the body surface. Heat loss per unit surface area via the beak more than doubled at Ta > 30.7°C compared to Ta < 30.7°C and at its peak dissipated 25.1 W m-2. Maximum heat flux rate across the beak of toucans under comparable convective conditions was calculated to be as high as 61.4 W m-2. The threshold air temperature at which toucans vasodilated their beak was lower than that of the hornbills, and thus had a larger potential for heat loss at lower air temperatures. Respiratory cooling (panting) thresholds were also lower in toucans compared to hornbills. Both beak vasodilation and panting threshold temperatures are potentially explained by differences in acclimation to environmental conditions and in the efficiency of evaporative cooling under differing environmental conditions. We speculate that non-evaporative heat dissipation may be a particularly important mechanism for animals inhabiting humid regions, such as toucans, and less critical for animals residing in more arid conditions, such as Southern Yellow-billed Hornbills. Alternatively, differences in beak morphology and hardness enforced by different diets may affect the capacity of birds to use the beak for non-evaporative heat loss.

Blytheville AFB, Arkansas, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1987-10-01

A USAFETAC Air Weather Service (MAC) 3SSTAe’ REVISED UNIFORM SUMMARY OF SURFACE WEATHER OBSERVATIONS BLYTHEVILLE AFB AR MSC 1723408 IC N 35 58 W...I IE C It I 1-3 4-b I-Il It 1 7-2 1 2 - 4- UC 4 1-4 7 4F - U S5 1(IA " SAN I9 I 1. . 217 2.0 .i D I .lF I .2 1.? .7 1 .1 1 .2 .2- 0.1I 7 I AIR4 3tf...o o o , . . .. . . .o ..oo.o.. 17-, -7 5C.-. 1-7 ’-, F t tt 71*1. Li I I L C1.2 4 t 7 1L 1 4 uC I* I. A .o o.....oo. oo ~ oo o ooo ...... ...... .o. o

Surface adsorption behaviour of milk whey protein and pectin mixtures under conditions of air-water interface saturation.

PubMed

Perez, Adrián A; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Rubiolo, Amelia C; Santiago, Liliana G

2011-07-01

Milk whey proteins (MWP) and pectins (Ps) are biopolymer ingredients commonly used in the manufacture of colloidal food products. Therefore, knowledge of the interfacial characteristics of these biopolymers and their mixtures is very important for the design of food dispersion formulations (foams and/or emulsions). In this paper, we examine the adsorption and surface dilatational behaviour of MWP/Ps systems under conditions in which biopolymers can saturate the air-water interface on their own. Experiments were performed at constant temperature (20 °C), pH 7 and ionic strength 0.05 M. Two MWP samples, β-lactoglobulin (β-LG) and whey protein concentrate (WPC), and two Ps samples, low-methoxyl pectin (LMP) and high-methoxyl pectin (HMP) were evaluated. The contribution of biopolymers (MWP and Ps) to the interfacial properties of mixed systems was evaluated on the basis of their individual surface molecular characteristics. Biopolymer bulk concentration capable of saturating the air-water interface was estimated from surface pressure isotherms. Under conditions of interfacial saturation, dynamic adsorption behaviour (surface pressure and dilatational rheological characteristics) of MWP/Ps systems was discussed from a kinetic point of view, in terms of molecular diffusion, penetration and configurational rearrangement at the air-water interface. The main adsorption mechanism in MWP/LMP mixtures might be the MWP interfacial segregation due to the thermodynamic incompatibility between MWP and LMP (synergistic mechanism); while the interfacial adsorption in MWP/HMP mixtures could be characterized by a competitive mechanism between MWP and HMP at the air-water interface (antagonistic mechanism). The magnitude of these phenomena could be closely related to differences in molecular composition and/or aggregation state of MWP (β-LG and WPC). Copyright © 2011 Elsevier B.V. All rights reserved.

Structure of the airflow above surface waves

NASA Astrophysics Data System (ADS)

Buckley, Marc; Veron, Fabrice

2016-04-01

Weather, climate and upper ocean patterns are controlled by the exchanges of momentum, heat, mass, and energy across the ocean surface. These fluxes are, in turn, influenced by the small-scale physics at the wavy air-sea interface. We present laboratory measurements of the fine-scale airflow structure above waves, achieved in over 15 different wind-wave conditions, with wave ages Cp/u* ranging from 1.4 to 66.7 (where Cp is the peak phase speed of the waves, and u* the air friction velocity). The experiments were performed in the large (42-m long) wind-wave-current tank at University of Delaware's Air-Sea Interaction laboratory (USA). A combined Particle Image Velocimetry and Laser Induced Fluorescence system was specifically developed for this study, and provided two-dimensional airflow velocity measurement as low as 100 um above the air-water interface. Starting at very low wind speeds (U10~2m/s), we directly observe coherent turbulent structures within the buffer and logarithmic layers of the airflow above the air-water interface, whereby low horizontal velocity air is ejected away from the surface, and higher velocity fluid is swept downward. Wave phase coherent quadrant analysis shows that such turbulent momentum flux events are wave-phase dependent. Airflow separation events are directly observed over young wind waves (Cp/u*<3.7) and counted using measured vorticity and surface viscous stress criteria. Detached high spanwise vorticity layers cause intense wave-coherent turbulence downwind of wave crests, as shown by wave-phase averaging of turbulent momentum fluxes. Mean wave-coherent airflow motions and fluxes also show strong phase-locked patterns, including a sheltering effect, upwind of wave crests over old mechanically generated swells (Cp/u*=31.7), and downwind of crests over young wind waves (Cp/u*=3.7). Over slightly older wind waves (Cp/u* = 6.5), the measured wave-induced airflow perturbations are qualitatively consistent with linear critical layer theory.

Molecular-level removal of proteinaceous contamination from model surfaces and biomedical device materials by air plasma treatment.

PubMed

Banerjee, K K; Kumar, S; Bremmell, K E; Griesser, H J

2010-11-01

Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Comparison and uncertainty evaluation of different calibration protocols and ionization chambers for low-energy surface brachytherapy dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Candela-Juan, C., E-mail: ccanjuan@gmail.com; Vijande, J.; García-Martínez, T.

2015-08-15

Purpose: A surface electronic brachytherapy (EBT) device is in fact an x-ray source collimated with specific applicators. Low-energy (<100 kVp) x-ray beam dosimetry faces several challenges that need to be addressed. A number of calibration protocols have been published for x-ray beam dosimetry. The media in which measurements are performed are the fundamental difference between them. The aim of this study was to evaluate the surface dose rate of a low-energy x-ray source with small field applicators using different calibration standards and different small-volume ionization chambers, comparing the values and uncertainties of each methodology. Methods: The surface dose rate ofmore » the EBT unit Esteya (Elekta Brachytherapy, The Netherlands), a 69.5 kVp x-ray source with applicators of 10, 15, 20, 25, and 30 mm diameter, was evaluated using the AAPM TG-61 (based on air kerma) and International Atomic Energy Agency (IAEA) TRS-398 (based on absorbed dose to water) dosimetry protocols for low-energy photon beams. A plane parallel T34013 ionization chamber (PTW Freiburg, Germany) calibrated in terms of both absorbed dose to water and air kerma was used to compare the two dosimetry protocols. Another PTW chamber of the same model was used to evaluate the reproducibility between these chambers. Measurements were also performed with two different Exradin A20 (Standard Imaging, Inc., Middleton, WI) chambers calibrated in terms of air kerma. Results: Differences between surface dose rates measured in air and in water using the T34013 chamber range from 1.6% to 3.3%. No field size dependence has been observed. Differences are below 3.7% when measurements with the A20 and the T34013 chambers calibrated in air are compared. Estimated uncertainty (with coverage factor k = 1) for the T34013 chamber calibrated in water is 2.2%–2.4%, whereas it increases to 2.5% and 2.7% for the A20 and T34013 chambers calibrated in air, respectively. The output factors, measured with the PTW chambers, differ by less than 1.1% for any applicator size when compared to the output factors that were measured with the A20 chamber. Conclusions: Measurements using both dosimetric protocols are consistent, once the overall uncertainties are considered. There is also consistency between measurements performed with both chambers calibrated in air. Both the T34013 and A20 chambers have negligible stem effect. Any x-ray surface brachytherapy system, including Esteya, can be characterized using either one of these calibration protocols and ionization chambers. Having less correction factors, lower uncertainty, and based on measurements, performed in closer to clinical conditions, the TRS-398 protocol seems to be the preferred option.« less

Air Superiority by the Numbers: Cutting Combat Air Forces in a Time of Uncertainty

DTIC Science & Technology

2014-06-01

5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) School of Advanced Air And Space Studies,,Air University,,Maxwell Air...iii ACKNOWLEDGMENTS I would first like to thank the men and women whom I have had the...interdiction role. Finally, in the midst of a growing Soviet radar-guided surface-to-air threat, “Skunk Works ” developed the first stealth attack

Accuracy of sea ice temperature derived from the advanced very high resolution radiometer

NASA Technical Reports Server (NTRS)

Yu, Y.; Rothrock, D. A.; Lindsay, R. W.

1995-01-01

The accuracy of Arctic sea ice surface temperatures T(sub s) dericed from advanced very high resolution radiometer (AVHRR) thermal channels is evaluated in the cold seasons by comparing them with surface air temperatures T(sub air) from drifting buoys and ice stations. We use three different estimates of satellite surface temperatures, a direct estimate from AVHRR channel 4 with only correction for the snow surface emissivity but not for the atmosphere, a single-channel regression of T(sub s) with T(sub air), and Key and Haefliger's (1992) polar multichannel algorithm. We find no measurable bias in any of these estimates and few differences in their statistics. The similar performance of all three methods indicates that an atmospheric water vapor correction is not important for the dry winter atmosphere in the central Arctic, given the other sources of error that remain in both the satellite and the comparison data. A record of drifting station data shows winter air temperature to be 1.4 C warmer than the snow surface temperature. `Correcting' air temperatures to skin temperature by subtracting this amount implies that satellite T(sub s) estimates are biased warm with respect to skin temperature by about this amount. A case study with low-flying aircraft data suggests that ice crystal precipitation can cause satellite estimates of T(sub s) to be several degrees warmer than radiometric measurements taken close to the surface, presumably below the ice crystal precipitation layer. An analysis in which errors are assumed to exist in all measurements, not just the satellite measurements, gives a standard deviation in the satellite estimates of 0.9 C, about half the standard deviation of 1.7 C estimated by assigning all the variation between T(sub s) and T(sub air) to errors in T(sub s).

Effectiveness of Different Urban Heat Island Mitigation Methods and Their Regional Impacts

NASA Astrophysics Data System (ADS)

Zhang, N.

2017-12-01

Cool roofs and green roofs are two popular methods to mitigate urban heat island and improve urban climate. The effectiveness of different urban heat island mitigation strategies in the summer of 2013 in the Yangtze River Delta, China is investigated using the WRF (Weather Research and Forecasting) model coupled with a physically based urban canopy model. The modifications to the roof surface changed the urban surface radiation balance and then modified the local surface energy budget. Both cool roofs and green roofs led to lower surface skin temperature and near-surface air temperature. Increasing the roof albedo to 0.5 caused a similar effectiveness as covering 25% of urban roofs with vegetation; increasing roof albedo to 0.7 caused a similar near-surface air temperature decrease as 75% green roof coverage. The near-surface relative humidity increased in both cool roof and green roof experiments because of the combination of the impacts of increases in specific humidity and decreases in air temperature. The regional impacts of cool roofs and green roofs were evaluated using the regional effect index. The regional effect could be found in both near-surface air temperature and surface specific/relative humidity when the percentage of roofs covered with high albedo materials or green roofs reached a higher fraction (greater than 50%). The changes in the vertical profiles of temperature cause a more stable atmospheric boundary layer over the urban area; at the same time, the crossover phenomena occurred above the boundary layer due to the decrease in vertical wind speed.

The Effect of Elevation Bias in Interpolated Air Temperature Data Sets on Surface Warming in China During 1951-2015

NASA Astrophysics Data System (ADS)

Wang, Tingting; Sun, Fubao; Ge, Quansheng; Kleidon, Axel; Liu, Wenbin

2018-02-01

Although gridded air temperature data sets share much of the same observations, different rates of warming can be detected due to different approaches employed for considering elevation signatures in the interpolation processes. Here we examine the influence of varying spatiotemporal distribution of sites on surface warming in the long-term trend and over the recent warming hiatus period in China during 1951-2015. A suspicious cooling trend in raw interpolated air temperature time series is found in the 1950s, and 91% of which can be explained by the artificial elevation changes introduced by the interpolation process. We define the regression slope relating temperature difference and elevation difference as the bulk lapse rate of -5.6°C/km, which tends to be higher (-8.7°C/km) in dry regions but lower (-2.4°C/km) in wet regions. Compared to independent experimental observations, we find that the estimated monthly bulk lapse rates work well to capture the elevation bias. Significant improvement can be achieved in adjusting the interpolated original temperature time series using the bulk lapse rate. The results highlight that the developed bulk lapse rate is useful to account for the elevation signature in the interpolation of site-based surface air temperature to gridded data sets and is necessary for avoiding elevation bias in climate change studies.

29 CFR 1910.425 - Surface-supplied air diving.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 5 2013-07-01 2013-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with bottom...

29 CFR 1910.425 - Surface-supplied air diving.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 5 2012-07-01 2012-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with bottom...

29 CFR 1910.425 - Surface-supplied air diving.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 5 2010-07-01 2010-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with bottom...

29 CFR 1910.425 - Surface-supplied air diving.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 5 2011-07-01 2011-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with bottom...

Augmentation Award for Surface Science Research Training.

DTIC Science & Technology

1996-11-01

atomic force microscopy facility. In particular, he designed an anechoic chamber for minimizing acoustical noise in our air and electrochemistry imaging...well as our new air/electochemical STM/AFM. In addition to the UHV-STM, the 11/20/96 10:43 e773 702 5863 J.F.I. I•On7 new air- levitated vactium rhnrher

40 CFR Table 7 to Subpart Kkkk of... - Default Organic HAP Mass Fraction for Petroleum Solvent Groups a

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 12 2011-07-01 2009-07-01 true Default Organic HAP Mass Fraction for... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants: Surface Coating of...

40 CFR Table 7 to Subpart Kkkk of... - Default Organic HAP Mass Fraction for Petroleum Solvent Groups a

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants: Surface Coating of...

Frost Growth and Densification on a Flat Surface in Laminar Flow with Variable Humidity

NASA Technical Reports Server (NTRS)

Kandula, M.

2012-01-01

Experiments are performed concerning frost growth and densification in laminar flow over a flat surface under conditions of constant and variable humidity. The flat plate test specimen is made of aluminum-6031, and has dimensions of 0.3 mx0.3 mx6.35 mm. Results for the first variable humidity case are obtained for a plate temperature of 255.4 K, air velocity of 1.77 m/s, air temperature of 295.1 K, and a relative humidity continuously ranging from 81 to 54%. The second variable humidity test case corresponds to plate temperature of 255.4 K, air velocity of 2.44 m/s, air temperature of 291.8 K, and a relative humidity ranging from 66 to 59%. Results for the constant humidity case are obtained for a plate temperature of 263.7 K, air velocity of 1.7 m/s, air temperature of 295 K, and a relative humidity of 71.6 %. Comparisons of the data with the author's frost model extended to accommodate variable humidity suggest satisfactory agreement between the theory and the data for both constant and variable humidity.

Characterization of Viral Load, Viability and Persistence of Influenza A Virus in Air and on Surfaces of Swine Production Facilities.

PubMed

Neira, Victor; Rabinowitz, Peter; Rendahl, Aaron; Paccha, Blanca; Gibbs, Shawn G; Torremorell, Montserrat

2016-01-01

Indirect transmission of influenza A virus (IAV) in swine is poorly understood and information is lacking on levels of environmental exposure encountered by swine and people during outbreaks of IAV in swine barns. We characterized viral load, viability and persistence of IAV in air and on surfaces during outbreaks in swine barns. IAV was detected in pigs, air and surfaces from five confirmed outbreaks with 48% (47/98) of oral fluid, 38% (32/84) of pen railing and 43% (35/82) of indoor air samples testing positive by IAV RT-PCR. IAV was isolated from air and oral fluids yielding a mixture of subtypes (H1N1, H1N2 and H3N2). Detection of IAV RNA from air was sustained during the outbreaks with maximum levels estimated between 7 and 11 days from reported onset. Our results indicate that during outbreaks of IAV in swine, aerosols and surfaces in barns contain significant levels of IAV potentially representing an exposure hazard to both swine and people.

Transfer, attachment, and formation of biofilms by Escherichia coli O157:H7 on meat-contact surface materials.

PubMed

Simpson Beauchamp, Catherine; Dourou, Dimitra; Geornaras, Ifigenia; Yoon, Yohan; Scanga, John A; Belk, Keith E; Smith, Gary C; Nychas, George-John E; Sofos, John N

2012-06-01

Studies examined the effects of meat-contact material types, inoculation substrate, presence of air at the liquid-solid surface interface during incubation, and incubation substrate on the attachment/transfer and subsequent biofilm formation by Escherichia coli O157:H7 on beef carcass fabrication surface materials. Materials studied as 2 × 5 cm coupons included stainless steel, acetal, polypropylene, and high-density polyethylene. A 6-strain rifampicin-resistant E. coli O157:H7 composite was used to inoculate (6 log CFU/mL, g, or cm²) tryptic soy broth (TSB), beef fat/lean tissue homogenate (FLH), conveyor belt-runoff fluids, ground beef, or beef fat. Coupons of each material were submerged (4 °C, 30 min) in the inoculated fluids or ground beef, or placed between 2 pieces of inoculated beef fat with pressure (20 kg) applied. Attachment/transfer of the pathogen was surface material and substrate dependent, although beef fat appeared to negate differences among surface materials. Beef fat was the most effective (P < 0.05) inoculation substrate, followed by ground beef, FLH, and TSB. Incubation (15 °C, 16 d) of beef fat-inoculated coupons in a beef fat homogenate (pH 4.21) allowed the pathogen to survive and grow on coupon surfaces, with maximal biofilm formation observed between 2 and 8 d of storage and when air was present at the liquid-solid interface. The results indicated that the process of fabricating beef carcasses may be conducive to the attachment of E. coli O157:H7 onto meat-contact surfaces and subsequent biofilm formation. Furthermore, it is recommended that substrates found in beef fabrication settings, rather than laboratory culture media, be used in studies designed to investigate E. coli O157:H7 biofilm development and control in these environments. Findings of this study provide knowledge on the effect of type of beef carcass fabrication surface material, fabrication-floor fluids and residues, and incubation conditions on attachment/transfer and subsequent biofilm formation by E. coli O157:H7. The results highlight the importance of thoroughly cleaning soiled surfaces to remove all remnants of beef fat or other organic material that may harbor or protect microbial contaminants during otherwise lethal antimicrobial interventions. © 2012 Institute of Food Technologists®

Effects of sulfate ligand on uranyl carbonato surface species on ferrihydrite surfaces

USGS Publications Warehouse

Arai, Yuji; Fuller, C.C.

2012-01-01

Understanding uranium (U) sorption processes in permeable reactive barriers (PRB) are critical in modeling reactive transport for evaluating PRB performance at the Fry Canyon demonstration site in Utah, USA. To gain insight into the U sequestration mechanism in the amorphous ferric oxyhydroxide (AFO)-coated gravel PRB, U(VI) sorption processes on ferrihydrite surfaces were studied in 0.01 M Na2SO4 solutions to simulate the major chemical composition of U-contaminatedgroundwater (i.e., [SO42-]~13 mM L-1) at the site. Uranyl sorption was greater at pH 7.5 than that at pH 4 in both air- and 2% pCO2-equilibrated systems. While there were negligible effects of sulfate ligands on the pH-dependent U(VI) sorption (<24 h) in both systems, X-ray absorption spectroscopy (XAS) analysis showed sulfate ligand associated U(VI) surface species at the ferrihydrite–water interface. In air-equilibrated systems, binary and mono-sulfate U(VI) ternary surface species co-existed at pH 5.43. At pH 6.55–7.83, a mixture of mono-sulfate and bis-carbonato U(VI) ternary surface species became more important. At 2% pCO2, there was no contribution of sulfate ligands on the U(VI) ternary surface species. Instead, a mixture of bis-carbonato inner-sphere (38%) and tris-carbonato outer-sphere U(VI) ternary surface species (62%) was found at pH 7.62. The study suggests that the competitive ligand (bicarbonate and sulfate) coordination on U(VI) surface species might be important in evaluating the U solid-state speciation in the AFO PRB at the study site where pCO2 fluctuates between 1 and 2 pCO2%.

Effects of sulfate ligand on uranyl carbonato surface species on ferrihydrite surfaces.

PubMed

Arai, Yuji; Fuller, C C

2012-01-01

Understanding uranium (U) sorption processes in permeable reactive barriers (PRB) are critical in modeling reactive transport for evaluating PRB performance at the Fry Canyon demonstration site in Utah, USA. To gain insight into the U sequestration mechanism in the amorphous ferric oxyhydroxide (AFO)-coated gravel PRB, U(VI) sorption processes on ferrihydrite surfaces were studied in 0.01 M Na(2)SO(4) solutions to simulate the major chemical composition of U-contaminated groundwater (i.e., [SO(4)(2-)] ~13 mM L(-1)) at the site. Uranyl sorption was greater at pH 7.5 than that at pH 4 in both air- and 2% pCO(2)-equilibrated systems. While there were negligible effects of sulfate ligands on the pH-dependent U(VI) sorption (<24 h) in both systems, X-ray absorption spectroscopy (XAS) analysis showed sulfate ligand associated U(VI) surface species at the ferrihydrite-water interface. In air-equilibrated systems, binary and mono-sulfate U(VI) ternary surface species co-existed at pH 5.43. At pH 6.55-7.83, a mixture of mono-sulfate and bis-carbonato U(VI) ternary surface species became more important. At 2% pCO(2), there was no contribution of sulfate ligands on the U(VI) ternary surface species. Instead, a mixture of bis-carbonato inner-sphere (38%) and tris-carbonato outer-sphere U(VI) ternary surface species (62%) was found at pH 7.62. The study suggests that the competitive ligand (bicarbonate and sulfate) coordination on U(VI) surface species might be important in evaluating the U solid-state speciation in the AFO PRB at the study site where pCO(2) fluctuates between 1 and 2 pCO(2)%. Copyright © 2011 Elsevier Inc. All rights reserved.

Interrelationships among Grain Size, Surface Composition, Air Stability, and Interfacial Resistance of Al-Substituted Li7La3Zr2O12 Solid Electrolytes.

PubMed

Cheng, Lei; Wu, Cheng Hao; Jarry, Angelique; Chen, Wei; Ye, Yifan; Zhu, Junfa; Kostecki, Robert; Persson, Kristin; Guo, Jinghua; Salmeron, Miquel; Chen, Guoying; Doeff, Marca

2015-08-19

The interfacial resistances of symmetrical lithium cells containing Al-substituted Li7La3Zr2O12 (LLZO) solid electrolytes are sensitive to their microstructures and histories of exposure to air. Air exposure of LLZO samples with large grain sizes (∼150 μm) results in dramatically increased interfacial impedances in cells containing them, compared to those with pristine large-grained samples. In contrast, a much smaller difference is seen between cells with small-grained (∼20 μm) pristine and air-exposed LLZO samples. A combination of soft X-ray absorption (sXAS) and Raman spectroscopy, with probing depths ranging from nanometer to micrometer scales, revealed that the small-grained LLZO pellets are more air-stable than large-grained ones, forming far less surface Li2CO3 under both short- and long-term exposure conditions. Surface sensitive X-ray photoelectron spectroscopy (XPS) indicates that the better chemical stability of the small-grained LLZO is related to differences in the distribution of Al and Li at sample surfaces. Density functional theory calculations show that LLZO can react via two different pathways to form Li2CO3. The first, more rapid, pathway involves a reaction with moisture in air to form LiOH, which subsequently absorbs CO2 to form Li2CO3. The second, slower, pathway involves direct reaction with CO2 and is favored when surface lithium contents are lower, as with the small-grained samples. These observations have important implications for the operation of solid-state lithium batteries containing LLZO because the results suggest that the interfacial impedances of these devices is critically dependent upon specific characteristics of the solid electrolyte and how it is prepared.

On the relationship between the Madden-Julian Oscillation and 2 m air temperature over central Asia in boreal winter

NASA Astrophysics Data System (ADS)

Zhou, Yang; Lu, Youyu; Yang, Ben; Jiang, Jing; Huang, Anning; Zhao, Yong; La, Mengke; Yang, Qing

2016-11-01

Linear regression is used to explore the relationship between the Madden-Julian oscillation (MJO) and 2 m air temperature (T2M) over central Asia in boreal winter during 1979-2012. During MJO phases 3 and 4 (7 and 8), T2M anomalies exhibit a significantly strong, negative (positive) response to the MJO from the Arabian Sea to northwestern China. The anomalies of T2M are essentially influenced by surface net downward long (Ldown) and shortwave radiations, which are caused by the changes in total cloud cover (TCC) and low-level tropospheric air temperature. The anomalies of Ldown that are caused by TCC account for 20-65% of total Ldown. The remaining anomalies of total Ldown are explained by low-level air temperature changes. The 850 hPa air temperature (T850) tendency is mainly affected by the vertical motion over central Asia during MJO phases 1, 2, 4-6, and 8, as well as over northern India during phases 3 and 7. Over Saudi Arabia, Afghanistan, Pakistan, Kazakhstan, and northwestern China, the anomalies of T850 tendency are mainly explained by the temperature advection during phases 3 and 7. TCC and vertical motion are affected by the evolution of the MJO event. The cyclonic (anticyclonic) circulation related to the MJO over central Asia during phases 3 and 4 (7 and 8) causes the transport of cold (warm) air over central Asia. The MJO can be a useful intraseasonal signal to predict winter T2M over central Asia, where temperatures would be colder (warmer) than normal during MJO phases 3 and 4 (7 and 8).

Correlation of gravestone decay and air quality 1960-2010

NASA Astrophysics Data System (ADS)

Mooers, H. D.; Carlson, M. J.; Harrison, R. M.; Inkpen, R. J.; Loeffler, S.

2017-03-01

Evaluation of spatial and temporal variability in surface recession of lead-lettered Carrara marble gravestones provides a quantitative measure of acid flux to the stone surfaces and is closely related to local land use and air quality. Correlation of stone decay, land use, and air quality for the period after 1960 when reliable estimates of atmospheric pollution are available is evaluated. Gravestone decay and SO2 measurements are interpolated spatially using deterministic and geostatistical techniques. A general lack of spatial correlation was identified and therefore a land-use-based technique for correlation of stone decay and air quality is employed. Decadally averaged stone decay is highly correlated with land use averaged spatially over an optimum radius of ≈7 km even though air quality, determined by records from the UK monitoring network, is not highly correlated with gravestone decay. The relationships among stone decay, air-quality, and land use is complicated by the relatively low spatial density of both gravestone decay and air quality data and the fact that air quality data is available only as annual averages and therefore seasonal dependence cannot be evaluated. However, acid deposition calculated from gravestone decay suggests that the deposition efficiency of SO2 has increased appreciably since 1980 indicating an increase in the SO2 oxidation process possibly related to reactions with ammonia.

Carbon Dioxide Removal from Air using Seafloor Peridotite

NASA Astrophysics Data System (ADS)

Kelemen, P. B.; Brandt, A. R.; Benson, S. M.

2016-12-01

We describe a method for Carbon Dioxide Removal from Air (CDR) using CO2 uptake via mineral carbonation, about half the cost of that proposed by Kelemen & Matter [1,2]. Reaction of CO2-bearing fluids and gases with peridotite rapidly forms inert, non-toxic carbonate minerals. In proposed methods for combined capture and storage of ambient CO2 via reaction of seawater or ground water with peridotite [1-5], return of depleted water to the surface draws down CO2 from air. Because they use available chemical and thermal energy that drive spontaneous natural reactions, they may be the least expensive methods for capture of CO2 from air. We focus on subsurface CO2 uptake during flow of surface water through fractured peridotite. Previously [1-3], we envisioned a design similar to enhanced geothermal systems (EGS), involving two large diameter boreholes, subject to the challenges of achieving rapid, efficient return flow that limit the success of EGS. Recent discussions yielded a less expensive, more robust design: A single well produces ambient, CO2-depleted pore water from seafloor peridotite. Such water has low carbon and high pH [6,7,8]. Where such waters are delivered to the surface, observations reveal rapid CO2 uptake from air [1,3,8-10]. Delivery to the sea surface would also reduce local acidification. Thermal buoyancy and pumps powered by wave and tidal energy would bring warm formation water from wells to the surface through conduits surrounded by colder seawater. Recharge would be via flow in natural or enhanced fracture networks in unconfined submarine aquifers. This method could be tested and scaled-up in coastal, sub-seafloor peridotite with onshore drilling off Oman, New Caledonia and Papua New Guinea, Spain, Morocco, USA, etc. It is possible to achieve much larger scale. Giant volumes of peridotite are exposed on the seafloor along slow-spreading mid-ocean ridges [3]. Robotic drills could install wells that deliver CO2-depleted water through fabric tubes to the sea surface. Does anyone know James Cameron's phone number? [1] Kelemen & Matter PNAS 08 [2] Kelemen & Matter AGU Fall 14 [3] Kelemen et al AREPS 11 [4] Wilson et al IJGHGC 14 [5] Schuiling & Krijgsman Climate Change 06 [6] Barnes & O'Neil GSA Bull 69 [7] Kelley et al Science 01 [8] Paukert et al Chem Geol 12 [9] Mervine et al GCA 13 [10] Mervine et al Chem Geol 15

Regulation of Heat Exchange across the Hornbill Beak: Functional Similarities with Toucans?

PubMed Central

Martin, R. O.; Vink, T. J. F.; McKechnie, A. E.; Cunningham, S. J.

2016-01-01

Beaks are increasingly recognised as important contributors to avian thermoregulation. Several studies supporting Allen’s rule demonstrate how beak size is under strong selection related to latitude and/or air temperature (Ta). Moreover, active regulation of heat transfer from the beak has recently been demonstrated in a toucan (Ramphastos toco, Ramphastidae), with the large beak acting as an important contributor to heat dissipation. We hypothesised that hornbills (Bucerotidae) likewise use their large beaks for non-evaporative heat dissipation, and used thermal imaging to quantify heat exchange over a range of air temperatures in eighteen desert-living Southern Yellow-billed Hornbills (Tockus leucomelas). We found that hornbills dissipate heat via the beak at air temperatures between 30.7°C and 41.4°C. The difference between beak surface and environmental temperatures abruptly increased when air temperature was within ~10°C below body temperature, indicating active regulation of heat loss. Maximum observed heat loss via the beak was 19.9% of total non-evaporative heat loss across the body surface. Heat loss per unit surface area via the beak more than doubled at Ta > 30.7°C compared to Ta < 30.7°C and at its peak dissipated 25.1 W m-2. Maximum heat flux rate across the beak of toucans under comparable convective conditions was calculated to be as high as 61.4 W m-2. The threshold air temperature at which toucans vasodilated their beak was lower than that of the hornbills, and thus had a larger potential for heat loss at lower air temperatures. Respiratory cooling (panting) thresholds were also lower in toucans compared to hornbills. Both beak vasodilation and panting threshold temperatures are potentially explained by differences in acclimation to environmental conditions and in the efficiency of evaporative cooling under differing environmental conditions. We speculate that non-evaporative heat dissipation may be a particularly important mechanism for animals inhabiting humid regions, such as toucans, and less critical for animals residing in more arid conditions, such as Southern Yellow-billed Hornbills. Alternatively, differences in beak morphology and hardness enforced by different diets may affect the capacity of birds to use the beak for non-evaporative heat loss. PMID:27192218

A Method to Correlate the Upper Air Density with Surface Density and Estimate the Ballistic Density for Air or Surface Launched Missiles.

DTIC Science & Technology

1982-07-01

MCANELLT. UNCLASSIFIED NSWC/TR-82-81 NL E1"EhhEEE ELE~hEEE i IEhh~~ E .,.u *~-*1 UNCLASSIFIED SECUMITY CLASSIFICATION OF THIS PAGE (When Data Entered...SURFACE LAUNCHED S. PERFORMING ORG. REPORT NUMBER ISSILES 7. AUTHOR(,) 6. CONTRACT OR GRANT NUMBER( e ) Loren J. McAnelly 9. PERFORMING ORGANIZATION NAME...ACKNOWLEDGEMENT The author would like to thank Dr. W. A. Kemper and Mr. Henry E . Castro for their help in preparing this report. Dr. Kemper provided

A Multiyear Dataset of SSM/I-Derived Global Ocean Surface Turbulent Fluxes

NASA Technical Reports Server (NTRS)

Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

2001-01-01

The surface turbulent fluxes of momentum, latent heat, and sensible heat over global oceans are essential to weather, climate and ocean problems. Evaporation is a key component of the hydrological cycle and the surface heat budget, while the wind stress is the major forcing for driving the oceanic circulation. The global air-sea fluxes of momentum, latent and sensible heat, radiation, and freshwater (precipitation-evaporation) are the forcing for driving oceanic circulation and, hence, are essential for understanding the general circulation of global oceans. The global air-sea fluxes are required for driving ocean models and validating coupled ocean-atmosphere global models. We have produced a 7.5-year (July 1987-December 1994) dataset of daily surface turbulent fluxes over the global oceans from the Special Sensor microwave/Imager (SSM/I) data. Daily turbulent fluxes were derived from daily data of SSM/I surface winds and specific humidity, National Centers for Environmental Prediction (NCEP) sea surface temperatures, and European Centre for Medium-Range Weather Forecasts (ECMWF) air-sea temperature differences, using a stability-dependent bulk scheme. The retrieved instantaneous surface air humidity (with a 25-km resolution) validated well with that of the collocated radiosonde observations over the global oceans. Furthermore, the retrieved daily wind stresses and latent heat fluxes were found to agree well with that of the in situ measurements (IMET buoy, RV Moana Wave, and RV Wecoma) in the western Pacific warm pool during the TOGA COARE intensive observing period (November 1992-February 1993). The global distributions of 1988-94 seasonal-mean turbulent fluxes will be presented. In addition, the global distributions of 1990-93 annual-means turbulent fluxes and input variables will be compared with those of UWM/COADS covering the same period. The latter is based on the COADS (comprehensive ocean-atmosphere data set) and is recognized to be one of the best climatological analyses of fluxes derived from ship observations.

7 CFR 29.3528 - Leaf surface.

Code of Federal Regulations, 2012 CFR

2012-01-01

... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf...

7 CFR 29.3528 - Leaf surface.

Code of Federal Regulations, 2010 CFR

2010-01-01

... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf...

7 CFR 29.3528 - Leaf surface.

Code of Federal Regulations, 2011 CFR

2011-01-01

... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf...

7 CFR 29.3528 - Leaf surface.

Code of Federal Regulations, 2013 CFR

2013-01-01

... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf...

7 CFR 29.3528 - Leaf surface.

Code of Federal Regulations, 2014 CFR

2014-01-01

... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf...

Dust control by air-blocking shelves and dust collector-to-bailing airflow ratios for a surface mine drill shroud

PubMed Central

Zheng, Y.; Reed, W.R.; Potts, J.D.; Li, M.; Rider, J.P.

2018-01-01

The National Institute for Occupational Safety and Health (NIOSH) recently developed a series of validated models utilizing computational fluid dynamics (CFD) to study the effects of air-blocking shelves on airflows and respirable dust distribution associated with medium-sized surface blasthole drill shrouds as part of a dry dust collector system. Using validated CFD models, three different air-blocking shelves were included in the present study: a 15.2-cm (6-in.)-wide shelf; a 7.6-cm (3-in.)-wide shelf; and a 7.6-cm (3-in.)-wide shelf at four different shelf heights. In addition, the dust-collector-to-bailing airflow ratios of 1.75:1, 1.5:1, 1.25:1 and 1:1 were evaluated for the 15.2-cm (6-in.)-wide air-blocking shelf. This paper describes the methodology used to develop the CFD models. The effects of air-blocking shelves and dust collector-to-bailing airflow ratios were identified by the study, and problem regions were revealed under certain conditions.

An analysis of spatial representativeness of air temperature monitoring stations

NASA Astrophysics Data System (ADS)

Liu, Suhua; Su, Hongbo; Tian, Jing; Wang, Weizhen

2018-05-01

Surface air temperature is an essential variable for monitoring the atmosphere, and it is generally acquired at meteorological stations that can provide information about only a small area within an r m radius ( r-neighborhood) of the station, which is called the representable radius. In studies on a local scale, ground-based observations of surface air temperatures obtained from scattered stations are usually interpolated using a variety of methods without ascertaining their effectiveness. Thus, it is necessary to evaluate the spatial representativeness of ground-based observations of surface air temperature before conducting studies on a local scale. The present study used remote sensing data to estimate the spatial distribution of surface air temperature using the advection-energy balance for air temperature (ADEBAT) model. Two target stations in the study area were selected to conduct an analysis of spatial representativeness. The results showed that one station (AWS 7) had a representable radius of about 400 m with a possible error of less than 1 K, while the other station (AWS 16) had the radius of about 250 m. The representable radius was large when the heterogeneity of land cover around the station was small.

Microbial air quality and bacterial surface contamination in ambulances during patient services.

PubMed

Luksamijarulkul, Pipat; Pipitsangjan, Sirikun

2015-03-01

We sought to assess microbial air quality and bacterial surface contamination on medical instruments and the surrounding areas among 30 ambulance runs during service. We performed a cross-sectional study of 106 air samples collected from 30 ambulances before patient services and 212 air samples collected during patient services to assess the bacterial and fungal counts at the two time points. Additionally, 226 surface swab samples were collected from medical instrument surfaces and the surrounding areas before and after ambulance runs. Groups or genus of isolated bacteria and fungi were preliminarily identified by Gram's stain and lactophenol cotton blue. Data were analyzed using descriptive statistics, t-test, and Pearson's correlation coefficient with a p-value of less than 0.050 considered significant. The mean and standard deviation of bacterial and fungal counts at the start of ambulance runs were 318±485cfu/m(3) and 522±581cfu/m(3), respectively. Bacterial counts during patient services were 468±607cfu/m(3) and fungal counts were 656±612cfu/m(3). Mean bacterial and fungal counts during patient services were significantly higher than those at the start of ambulance runs, p=0.005 and p=0.030, respectively. For surface contamination, the overall bacterial counts before and after patient services were 0.8±0.7cfu/cm(2) and 1.3±1.1cfu/cm(2), respectively (p<0.001). The predominant isolated bacteria and fungi were Staphylococcus spp. and Aspergillus spp., respectively. Additionally, there was a significantly positive correlation between bacterial (r=0.3, p<0.010) and fungal counts (r=0.2, p=0.020) in air samples and bacterial counts on medical instruments and allocated areas. This study revealed high microbial contamination (bacterial and fungal) in ambulance air during services and higher bacterial contamination on medical instrument surfaces and allocated areas after ambulance services compared to the start of ambulance runs. Additionally, bacterial and fungal counts in ambulance air showed a significantly positive correlation with the bacterial surface contamination on medical instruments and allocated areas. Further studies should be conducted to determine the optimal intervention to reduce microbial contamination in the ambulance environment.

Strength improvement and purification of Yb 2Si 2O 7-SiC nanocomposites by surface oxidation treatment

DOE PAGES

Nguyen, Son T.; Nakayama, Tadachika; Suematsu, Hisayuki; ...

2017-04-03

A two-step processing was developed to prepare Yb 2Si 2O 7-SiC nanocomposites. Yb 2Si 2O 7-Yb 2SiO 5-SiC composites were first fabricated by a solid state reaction/hot-pressing method. The composites were then annealed at 1250°C in air for 2 h to activate the oxidation of SiC, which effectively transformed the Yb 2SiO 5 into Yb 2Si 2O 7. The surface cracks purposely induced can be fully healed during the oxidation treatment. The treated composites have improved flexural strength compared to their pristine composites. As a result, the mechanism for crack-healing and silicate transformation have been proposed and discussed in detail.

Influence of storage methods on the surface roughness of tissue conditioners.

PubMed

Hong, Guan; Li, YingAi; Maeda, Takeshi; Mizumachi, Wataru; Sadamori, Shinsuke; Hamada, Taizo; Murata, Hiroshi

2008-03-01

The purpose of this study was to compare the influence of three kinds of storage methods on surface roughness of tissue conditioners. Four commercial tissue conditioners (GC Soft Liner, Softone, Fictioner, and Hydro-Cast) were used in this study. Five samples of each material were stored in distilled water, air, and a denture cleanser (Polident). Mean surface roughness (R(a)) values of dental stone casts made from the tissue conditioners were measured after 0, 1, 3, 7, and 14 days of immersion using a profilometer. Significant differences in the R(a) values of the specimens were found among the three storage methods. The values of R(a) significantly increased with increase in immersion time for each storage method, except for the materials stored in air. It was found that the materials stored in air showed the most stable and lowest values of R(a). Results obtained suggested that a tissue conditioner exhibited smooth and minimal change in surface roughness with time when stored in air than in distilled water and denture cleanser.

Modulating surface rheology by electrostatic protein/polysaccharide interactions.

PubMed

Ganzevles, Renate A; Zinoviadou, Kyriaki; van Vliet, Ton; Cohen, Martien A; de Jongh, Harmen H

2006-11-21

There is a large interest in mixed protein/polysaccharide layers at air-water and oil-water interfaces because of their ability to stabilize foams and emulsions. Mixed protein/polysaccharide adsorbed layers at air-water interfaces can be prepared either by adsorption of soluble protein/polysaccharide complexes or by sequential adsorption of complexes or polysaccharides to a previously formed protein layer. Even though the final protein and polysaccharide bulk concentrations are the same, the behavior of the adsorbed layers can be very different, depending on the method of preparation. The surface shear modulus of a sequentially formed beta-lactoglobulin/pectin layer can be up to a factor of 6 higher than that of a layer made by simultaneous adsorption. Furthermore, the surface dilatational modulus and surface shear modulus strongly (up to factors of 2 and 7, respectively) depend on the bulk -lactoglobulin/pectin mixing ratio. On the basis of the surface rheological behavior, a mechanistic understanding of how the structure of the adsorbed layers depends on the protein/polysaccharide interaction in bulk solution, mixing ratio, ionic strength, and order of adsorption to the interface (simultaneous or sequential) is derived. Insight into the effect of protein/polysaccharide interactions on the properties of adsorbed layers provides a solid basis to modulate surface rheological behavior.

Reaction of gas phase OH with unsaturated self-assembled monolayers and relevance to atmospheric organic oxidations.

PubMed

Moussa, Samar G; Finlayson-Pitts, Barbara J

2010-08-28

The kinetics and mechanisms of the reaction of gas phase OH radicals with organics on surfaces are of fundamental chemical interest, as well as relevant to understanding the degradation of organics on tropospheric surfaces or when they are components of airborne particles. We report here studies of the oxidation of a terminal alkene self-assembled monolayer (7-octenyltrichlorosilane, C8= SAM) on a germanium attenuated total reflectance crystal by OH radicals at a concentration of 2.1 x 10(5) cm(-3) at 1 atm total pressure and 298 K in air. Loss of the reactant SAM and the formation of surface products were followed in real time using infrared spectroscopy. From the rate of loss of the C=C bond, a reaction probability within experimental error of unity was derived. The products formed on the surface include organic nitrates and carbonyl compounds, with yields of 10 +/- 4% and < or = 7 +/- 4%, respectively, and there is evidence for the formation of organic products with C-O bonds such as alcohols, ethers and/or alkyl peroxides and possibly peroxynitrates. The yield of organic nitrates relative to carbonyl compounds is higher than expected based on analogous gas phase mechanisms, suggesting that the branching ratio for the RO(2) + NO reaction is shifted to favor the formation of organic nitrates when the reaction occurs on a surface. Water uptake onto the surface was only slightly enhanced upon oxidation, suggesting that oxidation per se cannot be taken as a predictor of increased hydrophilicity of atmospheric organics. These experiments indicate that the mechanisms for the surface reactions are different from gas phase reactions, but the OH oxidation of surface species will still be a significant contributor to determining their lifetimes in air.

Short-term production and synoptic influences on atmospheric 7Be concentrations

NASA Astrophysics Data System (ADS)

Usoskin, Ilya G.; Field, Christy V.; Schmidt, Gavin A.; LeppäNen, Ari-Pekka; Aldahan, Ala; Kovaltsov, Gennady A.; Possnert, GöRan; Ungar, R. Kurt

2009-03-01

Variations of the cosmogenic radionuclide 7Be in the global atmosphere are driven by cooperation of processes of its production, air transports, and removal. We use a combination of the Goddard Institute for Space Studies ModelE and the OuluCRAC:7Be production model to simulate the variations in the 7Be concentration in the atmosphere for the period from 1 January to 28 February 2005. This period features significant synoptic variability at multiple monitoring stations around the globe and spans an extreme solar energetic particle (SEP) event that occurred on 20 January. Using nudging from observed horizontal winds, the model correctly reproduces the overall level of the measured 7Be concentration near ground and a great deal of the synoptic variability at timescales of 4 days and longer. This verifies the combined model of production and transport of the 7Be radionuclide in the atmosphere. The impact of an extreme SEP event of January 2005 is seen dramatically in polar stratospheric 7Be concentration but is small near the surface (about 2%) and indistinguishable given the amount of intrinsic variability and the uncertainties of the surface observations.

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., and (3) The average carbon dioxide concentration is 1.0 percent or less and excursions do not exceed 2... removal of carbon dioxide. (2) The analysis or study shall identify the means used to prevent any ignition... compressors shall meet the following: (i) Be equipped with a carbon monoxide detector located at the surface...

Atmospheric Structure. Part 3. Upper Air and Surface Data: Stallion Site

DTIC Science & Technology

1975-01-01

Structure Part 3, Upper Air and Surface Data Stallion Site S. TYPE OF REPORT & PERIOD COVERED 6- PERFORMING ORG. REPORT NUMBER 7. AUTHORS...Marjorie M. Hoidale Michael P. Dayton Lamar Newman •. CONTRACT OR GRANT NUMBERS DA Task 1T665702D127-02 9. PERFORMING ORGANIZATION NAME AND ADORESS 10...Sciences Laboratory White Sands Missile Ran^e, New Mexico 12. REPORT DATE January 1975 13. NUMBER OF PAGES «Ä33 ; U MONITORING AGENCY NAME

Surface Rupture Map of the 2002 M7.9 Denali Fault Earthquake, Alaska: Digital Data

USGS Publications Warehouse

Haeussler, Peter J.

2009-01-01

The November 3, 2002, Mw7.9 Denali Fault earthquake produced about 340 km of surface rupture along the Susitna Glacier Thrust Fault and the right-lateral, strike-slip Denali and Totschunda Faults. Digital photogrammetric methods were primarily used to create a 1:500-scale, three-dimensional surface rupture map, and 1:6,000-scale aerial photographs were used for three-dimensional digitization in ESRI's ArcMap GIS software, using Leica's StereoAnalyst plug in. Points were digitized 4.3 m apart, on average, for the entire surface rupture. Earthquake-induced landslides, sackungen, and unruptured Holocene fault scarps on the eastern Denali Fault were also digitized where they lay within the limits of air photo coverage. This digital three-dimensional fault-trace map is superior to traditional maps in terms of relative and absolute accuracy, completeness, and detail and is used as a basis for three-dimensional visualization. Field work complements the air photo observations in locations of dense vegetation, on bedrock, or in areas where the surface trace is weakly developed. Seventeen km of the fault trace, which broke through glacier ice, were not digitized in detail due to time constraints, and air photos missed another 10 km of fault rupture through the upper Black Rapids Glacier, so that was not mapped in detail either.

Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

NASA Technical Reports Server (NTRS)

Glass, Christopher E.

1990-01-01

The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.

Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

NASA Astrophysics Data System (ADS)

Glass, Christopher E.

1990-08-01

The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.

Temporal Changes in the Observed Relationship between Cloud Cover and Surface Air Temperature.

NASA Astrophysics Data System (ADS)

Sun, Bomin; Groisman, Pavel Ya.; Bradley, Raymond S.; Keimig, Frank T.

2000-12-01

The relationship between cloud cover and near-surface air temperature and its decadal changes are examined using the hourly synoptic data for the past four to six decades from five regions of the Northern Hemisphere: Canada, the United States, the former Soviet Union, China, and tropical islands of the western Pacific. The authors define the normalized cloud cover-surface air temperature relationship, NOCET or dT/dCL, as a temperature anomaly with a unit (one-tenth) deviation of total cloud cover from its average value. Then mean monthly NOCET time series (night- and daytime, separately) are area-averaged and parameterized as functions of surface air humidity and snow cover. The day- and nighttime NOCET variations are strongly anticorrelated with changes in surface humidity. Furthermore, the daytime NOCET changes are positively correlated to changes in snow cover extent. The regionally averaged nighttime NOCET varies from 0.05 K tenth1 in the wet Tropics to 1.0 K tenth1 at midlatitudes in winter. The daytime regional NOCET ranges from 0.4 K tenth1 in the Tropics to 0.7 K tenth1 at midlatitudes in winter.The authors found a general strengthening of a daytime surface cooling during the post-World War II period associated with cloud cover over the United States and China, but a minor reduction of this cooling in higher latitudes. Furthermore, since the 1970s, a prominent increase in atmospheric humidity has significantly weakened the effectiveness of the surface warming (best seen at nighttime) associated with cloud cover.The authors apportion the spatiotemporal field of interactions between total cloud cover and surface air temperature into a bivariate relationship (described by two equations, one for daytime and one for nighttime) with surface air humidity and snow cover and two constant factors. These factors are invariant in space and time domains. It is speculated that they may represent empirical estimates of the overall cloud cover effect on the surface air temperature.

Potential impacts of electric vehicles on air quality in Taiwan.

PubMed

Li, Nan; Chen, Jen-Ping; Tsai, I-Chun; He, Qingyang; Chi, Szu-Yu; Lin, Yi-Chiu; Fu, Tzung-May

2016-10-01

The prospective impacts of electric vehicle (EV) penetration on the air quality in Taiwan were evaluated using an air quality model with the assumption of an ambitious replacement of current light-duty vehicles under different power generation scenarios. With full EV penetration (i.e., the replacement of all light-duty vehicles), CO, VOCs, NOx and PM2.5 emissions in Taiwan from a fleet of 20.6 million vehicles would be reduced by 1500, 165, 33.9 and 7.2Ggyr(-1), respectively, while electric sector NOx and SO2 emissions would be increased by up to 20.3 and 12.9Ggyr(-1), respectively, if the electricity to power EVs were provided by thermal power plants. The net impacts of these emission changes would be to reduce the annual mean surface concentrations of CO, VOCs, NOx and PM2.5 by about 260, 11.3, 3.3ppb and 2.1μgm(-3), respectively, but to increase SO2 by 0.1ppb. Larger reductions tend to occur at time and place of higher ambient concentrations and during high pollution events. Greater benefits would clearly be attained if clean energy sources were fully encouraged. EV penetration would also reduce the mean peak-time surface O3 concentrations by up to 7ppb across Taiwan with the exception of the center of metropolitan Taipei where the concentration increased by <2ppb. Furthermore, full EV penetration would reduce annual days of O3 pollution episodes by ~40% and PM2.5 pollution episodes by 6-10%. Our findings offer important insights into the air quality impacts of EV and can provide useful information for potential mitigation actions. Copyright © 2016 Elsevier B.V. All rights reserved.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Ghent, D.; Rayner, N. A.

2017-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-2018, https://www.eustaceproject.eu) we have developed an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. This includes developing new "Big Data" analysis methods as the data volumes involved are considerable. We will present recent progress along this road in the EUSTACE project, i.e.: • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

Air pollution and climate response to aerosol direct radiative ...

EPA Pesticide Factsheets

Decadal hemispheric Weather Research and Forecast-Community Multiscale Air Quality simulations from 1990 to 2010 were conducted to examine the meteorology and air quality responses to the aerosol direct radiative effects. The model's performance for the simulation of hourly surface temperature, relative humidity, wind speed, and direction was evaluated through comparison with observations from NOAA's National Climatic Data Center Integrated Surface Data. The inclusion of aerosol direct radiative effects improves the model's ability to reproduce the trend in daytime temperature range which over the past two decades was increasing in eastern China but decreasing in eastern U.S. and Europe. Trends and spatial and diurnal variations of the surface-level gaseous and particle concentrations to the aerosol direct effect were analyzed. The inclusion of aerosol direct radiative effects was found to increase the surface-level concentrations of SO2, NO2, O3, SO42−, NO3−, and particulate matter 2.5 in eastern China, eastern U.S., and Europe by 1.5–2.1%, 1–1.5%, 0.1–0.3%, 1.6–2.3%, 3.5–10.0%, and 2.2–3.2%, respectively, on average over the entire 21 year period. However, greater impacts are noted during polluted days with increases of 7.6–10.6%, 6.2–6.7%, 2.0–3.0%, 7.8–9.5%, 11.1–18.6%, and 7.2–10.1%, respectively. Due to the aerosol direct radiative effects, stabilizing of the atmosphere associated with reduced planetary boundary layer height a

International Conference on Curves and Surfaces (4th), Saint-Malo, France, 1-7 July 1999. Proceedings, Volume 1. Curve and Surface Design

DTIC Science & Technology

2000-04-01

the Air Force grant issued by the European Aerospace Office of Research and Development. The United States has a royalty free license throughout the...UNIVERSITY PRESS Nashville fl9 ~Oc -O i U.S. Government Rights License This work relates to Department of the Air Force Grant/rContract issued by the...in engineering , medicine, and the sciences. SERIES EDITOR: Larry L. Schumaker Stevenson Professor of Mathematics Vanderbilt University PREVIOUSLY

Test methods and response surface models for hot, humid air decontamination of materials contaminated with dirty spores of Bacillus anthracis ∆Sterne and Bacillus thuringiensis Al Hakam.

PubMed

Buhr, T L; Young, A A; Barnette, H K; Minter, Z A; Kennihan, N L; Johnson, C A; Bohmke, M D; DePaola, M; Cora-Laó, M; Page, M A

2015-11-01

To develop test methods and evaluate survival of Bacillus anthracis ∆Sterne or Bacillus thuringiensis Al Hakam on materials contaminated with dirty spore preparations after exposure to hot, humid air using response surface modelling. Spores (>7 log10 ) were mixed with humic acid + spent sporulation medium (organic debris) or kaolin (dirt debris). Spore samples were then dried on five different test materials (wiring insulation, aircraft performance coating, anti-skid, polypropylene, and nylon). Inoculated materials were tested with 19 test combinations of temperature (55, 65, 75°C), relative humidity (70, 80, 90%) and time (1, 2, 3 days). The slowest spore inactivation kinetics was on nylon webbing and/or after addition of organic debris. Hot, humid air effectively decontaminates materials contaminated with dirty Bacillus spore preparations; debris and material interactions create complex decontamination kinetic patterns; and B. thuringiensis Al Hakam is a realistic surrogate for B. anthracis. Response surface models of hot, humid air decontamination were developed which may be used to select decontamination parameters for contamination scenarios including aircraft. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Improving representation of canopy temperatures for modeling subcanopy incoming longwave radiation to the snow surface

NASA Astrophysics Data System (ADS)

Webster, Clare; Rutter, Nick; Jonas, Tobias

2017-09-01

A comprehensive analysis of canopy surface temperatures was conducted around a small and large gap at a forested alpine site in the Swiss Alps during the 2015 and 2016 snowmelt seasons (March-April). Canopy surface temperatures within the small gap were within 2-3°C of measured reference air temperature. Vertical and horizontal variations in canopy surface temperatures were greatest around the large gap, varying up to 18°C above measured reference air temperature during clear-sky days. Nighttime canopy surface temperatures around the study site were up to 3°C cooler than reference air temperature. These measurements were used to develop a simple parameterization for correcting reference air temperature for elevated canopy surface temperatures during (1) nighttime conditions (subcanopy shortwave radiation is 0 W m-2) and (2) periods of increased subcanopy shortwave radiation >400 W m-2 representing penetration of shortwave radiation through the canopy. Subcanopy shortwave and longwave radiation collected at a single point in the subcanopy over a 24 h clear-sky period was used to calculate a nighttime bulk offset of 3°C for scenario 1 and develop a multiple linear regression model for scenario 2 using reference air temperature and subcanopy shortwave radiation to predict canopy surface temperature with a root-mean-square error (RMSE) of 0.7°C. Outside of these two scenarios, reference air temperature was used to predict subcanopy incoming longwave radiation. Modeling at 20 radiometer locations throughout two snowmelt seasons using these parameterizations reduced the mean bias and RMSE to below 10 W m s-2 at all locations.

Molecular recognition of 7-(2-octadecyloxycarbonylethyl)guanine to cytidine at the air/water interface and LB film studied by Fourier transform infrared spectroscopy

NASA Astrophysics Data System (ADS)

Miao, Wangen; Luo, Xuzhong; Liang, Yingqiu

2003-03-01

Monolayer behavior of a nucleolipid amphiphile, 7-(2-octadecyloxycarbonylethyl)guanine (ODCG), on aqueous cytidine solution was investigated by means of surface-molecular area ( π- A) isotherms. It indicates that molecular recognition by hydrogen bonding is present between ODCG monolayer and the cytidine in subphase. The Fourier transform infrared (FTIR) transmission spectroscopic result indicates that the cytidine molecules in the subphase can be transferred onto solid substrates by Langmuir-Blodgett (LB) technique as a result of the formation of Watson-Crick base-pairing at the air/water interface. Investigation by rotating polarized FTIR transmission also suggests that the headgroup recognition of this amphiphile to the dissolved cytidine influence the orientation of the tailchains.

Meteorological and urban landscape factors on severe air pollution in Beijing.

PubMed

Han, Lijian; Zhou, Weiqi; Li, Weifeng; Meshesha, Derege T; Li, Li; Zheng, Mingqing

2015-07-01

Air pollution gained special attention with the rapid development in Beijing. In January 2013, Beijing experienced extreme air pollution, which was not well examined. We thus examine the magnitude of air quality in the particular month by applying the air quality index (AQI), which is based on the newly upgraded Chinese environmental standard. Our finding revealed that (1) air quality has distinct spatial heterogeneity and relatively better air quality was observed in the northwest while worse quality happened in the southeast part of the city; (2) the wind speed is the main determinant of air quality in the city-when wind speed is greater than 4 m/sec, air quality can be significantly improved; and (3) urban impervious surface makes a contribution to the severity of air pollution-that is, with an increase in the fraction of impervious surface in a given area, air pollution is more severe. The results from our study demonstrated the severe pollution in Beijing and its meteorological and landscape factors. Also, the results of this work suggest that very strict air quality management should be conducted when wind speed less than 4 m/sec, especially at places with a large fraction of urban impervious surface. Prevention of air pollution is rare among methods with controls on meteorological and urban landscape conditions. We present research that utilizes the latest air quality index (AQI) to compare air pollution with meteorological and landscape conditions. We found that wind is the major meteorological factor that determines the air quality. For a given wind speed greater than 4 m/sec, the air quality improved significantly. Urban impervious surface also contributes to the severe air pollution: that is, when the fraction of impervious surface increases, there is more severe air pollution. These results suggest that air quality management should be conducted when wind speed is less than 4 m/sec, especially at places with a larger fraction of urban impervious surface.

Influence of different air-abrasive powders on cell viability at biologically contaminated titanium dental implants surfaces.

PubMed

Schwarz, Frank; Ferrari, Daniel; Popovski, Kristian; Hartig, Brigitte; Becker, Jürgen

2009-01-01

Studies have indicated that oral biofilm formation at structured titanium surfaces interferes with cell adhesion and proliferation, and its removal by means of conventional treatment procedures may not be sufficient to render these surfaces biologically acceptable. Therefore, the aim of the study was to evaluate the influence of different air-abrasive powders on cell viability at biologically contaminated titanium dental implant surfaces. Intraoral splints were used to collect an in vivo biofilm on sandblasted and acid-etched titanium discs for 48 h. A single (1x) and repeated (2x) use of four different powders (amino acid glycine or sodium bicarbonate particles; range of mean particle size (d(v50)):20-75 microm) was applied at two distances (1 and 2 mm) and angles (30 degrees and 90 degrees) to the surfaces. Specimens (2x) were incubated with SaOs-2 cells for 7 days. Residual biofilm (RB) areas (%), and surface alterations (SEM) (1x and 2x), as well as SaOs-2 cell viability, expressed as mitochondrial cell activity (MA) (counts/second) (2x specimens), were assessed. Comparable mean RB areas were observed within and between groups after both 1x (RB: 0.0% +/- 0.0% to 5.7% +/- 5.7%) and 2x (RB: 0.0% +/- 0.0%) treatments. All surface treatments did not lead to MA (2x) values comparable to the sterile control group. However, sodium bicarbonate particles resulted in significantly higher MA (2x) values than amino acid glycine powders of different sizes. This was associated with pronounced alterations of the surface morphology (2x). Within the limits of the present study, it was concluded that SaOs-2 cell viability at biologically contaminated titanium surfaces was mainly influenced by the particle type of the powder. (c) 2008 Wiley Periodicals, Inc.

Environmental survey to assess viral contamination of air and surfaces in hospital settings.

PubMed

Carducci, A; Verani, M; Lombardi, R; Casini, B; Privitera, G

2011-03-01

The presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. Direct viral detection in the environment poses significant technical problems and the indirect indicators currently in use suffer from serious limitations. The aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis C virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. In total, 114 surface and 62 air samples were collected. Bacterial contamination was very low (<1 cfu/cm(2)) on surfaces, whereas the 'medium' detected value in air was 282 cfu/m(3). Overall, 19 (16.7%) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and 17 (14.9%) for torque teno virus (TTV). Only this latter virus was directly detected in 10 air samples (16.1%). Haemoglobin was found on two surfaces. No relationship was found between viral, biochemical or bacterial indicators. The data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. The frequent detection of TTV suggests its possible use as an indicator for general viral contamination of the environment. Copyright © 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Rayner, Nick

2017-04-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project: 1. providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; 2. identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; 3. estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; 4. using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

The EUSTACE project: delivering global, daily information on surface air temperature

NASA Astrophysics Data System (ADS)

Ghent, D.; Rayner, N. A.

2016-12-01

Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, in the EUSTACE project (2015-June 2018, https://www.eustaceproject.eu) we are developing an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals is used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods. We will present recent progress along this road in the EUSTACE project, i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras. Information will also be given on how interested users can become involved.

High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

NASA Technical Reports Server (NTRS)

Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

2004-01-01

The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to atmosphere. We anticipate future improvements in the AIRS retrieval algorithm will lead to improved understanding of the exchange of sensible and latent heat from ocean to atmosphere, and more realistic near-surface lapse rates.

Elongated solid electrolyte cell configurations and flexible connections therefor

DOEpatents

Reichner, Philip

1989-01-01

A flexible, high temperature, solid oxide electrolyte electrochemical cell stack configuration is made, comprising a plurality of flattened, elongated, connected cell combinations 1, each cell combination containing an interior electrode 2 having a top surface and a plurality of interior gas feed conduits 3, through its axial length, electrolyte 5 contacting the interior electrode and exterior electrode 8 contacting electrolyte, where a major portion of the air electrode top surface 7 is covered by interconnection material 6, and where each cell has at least one axially elongated, electronically conductive, flexible, porous, metal fiber felt material 9 in electronic connection with the air electrode 2 through contact with a major portion of the interconnection material 6, the metal fiber felt being effective as a shock absorbent body between the cells.

Penicillium populations in dry-cured ham manufacturing plants.

PubMed

Battilani, Paola; Pietri, V Amedeo; Giorni, Paola; Formenti, Silvia; Bertuzzi, Terenzio; Toscani, Tania; Virgili, Roberta; Kozakiewicz, Zofia

2007-04-01

Seven ham manufacturing plants were sampled for 1 year to assess the mycoflora present in the air and on hams, with special attention given to potential mycotoxin producers. Temperature and relative humidity were recorded in the ripening rooms. Maturing rooms held hams from 2 to 3 through 6 to 7 ripening months, and aging rooms held hams for the following 6 to 7 months, until the 14-month ripening point, when they were ready for the market. Mean temperatures and relative humidities registered during the study were 14.9 degrees C and 62.4%, respectively, in maturing rooms and 16.3 degrees C and 57.6% in aging rooms. Aspergilli and penicillia, potential mycotoxin producers, were isolated in all the plants from the air and the ham. Aspergilli represented 5% of the isolates, while penicillia were largely dominant, with Penicillium nalgiovense being the most represented species (around 60% of the penicillia), followed by Penicillium nordicum, with 10 and 26% of the penicillia isolated, respectively, from the air or the ham. Ochratoxin A production ability, checked in vitro at 250C, was observed in 50% of the P. nordicum isolates obtained both from the air and the ham. Air and ham surface contamination by penicillia was greater in the ripening rooms, where higher temperatures were registered. A certain correlation was also observed between air and ham surface contamination. On the basis of this study, P. nordicum, the ochratoxin A producer that is notable on proteinaceous substrates, is normally present in ham manufacturing plants in Italy, even though not a dominant species. Further studies are necessary to clarify and ensure if dry-curing conditions minimize the potential risk of ochratoxin A formation in the product.

Comparing AIRS/AMSU-A Satellite and MERRA/MERRA-2 Reanalysis products with In-situ Station Observations at Summit, Greenland

NASA Astrophysics Data System (ADS)

Hearty, T. J., III; Vollmer, B.; Wei, J. C.; Huwe, P. M.; Albayrak, A.; Wu, D. L.; Cullather, R. I.; Meyer, D. L.; Lee, J. N.; Blaisdell, J. M.; Susskind, J.; Nowicki, S.

2017-12-01

The surface air and skin temperatures reported by the Atmospheric Infrared Sounder (AIRS), the Modern-Era Retrospective analysis for Research and Applications (MERRA), and MERRA-2 at Summit, Greenland are compared with near surface air temperatures measured at National Oceanic and Atmospheric Administration (NOAA) and Greenland Climate Network (GC-Net) weather stations. Therefore this investigation requires familiarity with a heterogeneous set of swath, grid, and point data in several different formats, different granularity, and different sampling. We discuss the current subsetting capabilities available at the GES DISC (Goddard Earth Sciences Data Information Services Center) to perform the inter-comparisons necessary to evaluate the quality and trustworthiness of these datasets. We also explore potential future services which may assist users with this type of intercomparison. We find the AIRS Surface Skin Temperature (TS) is best correlated with the NOAA 2 m air temperature (T2M) but it tends to be colder than the station measurements. The difference may be the result of the frequent near surface temperature inversions in the region. The AIRS Surface Air Temperature (SAT) is also well correlated with the NOAA T2M but it has a warm bias with respect to the NOAA T2M during the cold season and a larger standard error than surface temperature. This suggests that the extrapolation of the temperature profile to the surface is not valid for the strongest inversions. Comparing the temperature lapse rate derived from the 2 stations shows that the lapse rate can increase closer to the surface. We also find that the difference between the AIRS SAT and TS is sensitive to near surface inversions. The MERRA-2 surface and near surface temperatures show improvements over MERRA but little sensitivity to near surface temperature inversions.

40 CFR 52.1167 - EPA-approved Massachusetts State regulations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 48303 c(117) Adds the following coating operations: plastic parts surface coating, leather surface... Includes Berkshire Air Pollution Control District to 7.05(4)(b)(2) so facilities in that district can apply....18(21) Surface coating of plastic parts 2/17/93 9/3/1999 64 FR 48304 c(117) Adds VOC RACT for plastic...

Diffusion of volatile organics through porous snow: impact of surface adsorption and grain boundaries

NASA Astrophysics Data System (ADS)

Bartels-Rausch, T.; Wren, S. N.; Schreiber, S.; Riche, F.; Schneebeli, M.; Ammann, M.

2013-07-01

Release of trace gases from surface snow on earth drives atmospheric chemistry, especially in the polar regions. The gas-phase diffusion of methanol and of acetone through the interstitial air of snow was investigated in a well-controlled laboratory study in the temperature range of 223 to 263 K. The aim of this study was to evaluate how the structure of the snowpack, the interaction of the trace gases with the snow surface, and the grain boundaries influence the diffusion on timescales up to 1 h. The diffusive loss of these two volatile organics into packed snow samples was measured using a chemical ionization mass spectrometer. The structure of the snow was analysed by means of X-ray-computed micro-tomography. The observed diffusion profiles could be well described based on gas-phase diffusion and the known structure of the snow sample at temperatures ≥ 253 K. At colder temperatures, surface interactions start to dominate the diffusive transport. Parameterizing these interactions in terms of adsorption to the solid ice surface, i.e. using temperature-dependent air-ice partitioning coefficients, better described the observed diffusion profiles than the use of air-liquid partitioning coefficients. No changes in the diffusive fluxes were observed by increasing the number of grain boundaries in the snow sample by a factor of 7, indicating that for these volatile organic trace gases, uptake into grain boundaries does not play a role on the timescale of diffusion through porous surface snow. For this, a snow sample with an artificially high amount of ice grains was produced and the grain boundary surface measured using thin sections. In conclusion, we have shown that the diffusivity can be predicted when the structure of the snowpack and the partitioning of the trace gas to solid ice is known.

Temperature Mapping of Air Film-Cooled Thermal Barrier Coated Surfaces Using Phosphor Thermometry

NASA Technical Reports Server (NTRS)

Eldridge, Jeffrey I.

2016-01-01

While the effects of thermal barrier coating (TBC) thermal protection and air film cooling effectiveness for jet engine components are usually studied separately, their contributions to combined cooling effectiveness are interdependent and are not simply additive. Therefore, combined cooling effectiveness must be measured to achieve an optimum balance between TBC thermal protection and air film cooling. Phosphor thermometry offers several advantages for mapping temperatures of air film cooled surfaces. While infrared thermography has been typically applied to study air film cooling effectiveness, temperature accuracy depends on knowing surface emissivity (which may change) and correcting for effects of reflected radiation. Because decay time-based full-field phosphor thermometry is relatively immune to these effects, it can be applied advantageously to temperature mapping of air film-cooled TBC-coated surfaces. In this presentation, an overview will be given of efforts at NASA Glenn Research Center to perform temperature mapping of air film-cooled TBC-coated surfaces in a burner rig test environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and the strengths and limitations of this method for studying air film cooling effectiveness are discussed.

Studies of Cosmic Ray Composition and Air Shower Structure with the Pierre Auger Observatory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abraham, : J.; Abreu, P.; Aglietta, M.

2009-06-01

These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the average depth of shower maximum and its fluctuations with the Pierre Auger Observatory; (2) Study of the nuclear mass composition of UHECR with the surface detectors of the Pierre Auger Observatory; (3) Comparison of data from the Pierre Auger Observatory with predictions from air shower simulations: testing models of hadronic interactions; (4) A Monte Carlo exploration of methods to determine the UHECR composition with the Pierre Auger Observatory; (5) The delaymore » of the start-time measured with the Pierre Auger Observatory for inclined showers and a comparison of its variance with models; (6) UHE neutrino signatures in the surface detector of the Pierre Auger Observatory; and (7) The electromagnetic component of inclined air showers at the Pierre Auger Observatory.« less

Development of a 3-D Pen Input Device

DTIC Science & Technology

2008-09-01

of a unistroke which can be written on any surface or in the air while correcting integration errors from the...navigation frame of a unistroke, which can be written on any surface or in the air while correcting integration errors from the measurements of the IMU... be written on any surface or in the air while correcting integration errors from the measurements of the IMU (Inertial Measurement Unit) of the

Correlation of Superior Canal Dehiscence Surface Area With Vestibular Evoked Myogenic Potentials, Audiometric Thresholds, and Dizziness Handicap.

PubMed

Hunter, Jacob B; O'Connell, Brendan P; Wang, Jianing; Chakravorti, Srijata; Makowiec, Katie; Carlson, Matthew L; Dawant, Benoit; McCaslin, Devin L; Noble, Jack H; Wanna, George B

2016-09-01

To correlate objective measures of vestibular and audiometric function as well as subjective measures of dizziness handicap with the surface area of the superior canal dehiscence (SCD). Retrospective chart review and radiological analysis. Single tertiary academic referral center. Preoperative computed tomography imaging, patient survey, audiometric thresholds, and vestibular evoked myogenic potential (VEMP) testing in patients with confirmed SCD. Image analysis techniques were developed to measure the surface area of each SCD in computed tomography imaging. Preoperative ocular and cervical VEMPs, air and bone conduction thresholds, air-bone gap, dizziness handicap inventory scores, and surface area of the SCD. Fifty-three patients (mean age 52.7 yr) with 84 SCD were analyzed. The median surface area of dehiscence was 1.44 mm (0.068-8.23 mm). Ocular VEMP amplitudes (r = 0.61, p <0.0001), cervical VEMP amplitudes (r = 0.62, p <0.0001), air conduction thresholds at 250 Hz (r = 0.25, p = 0.043), and air-bone gap at 500 Hz (r = 0.27, p = 0.01) positively correlated with increasing size of dehiscence. An inverse relationship between cervical VEMP thresholds (r = -0.56, p < 0.0001) and surface area of the dehiscence was observed. No association between dizziness handicap and surface area was identified. Among patients with confirmed SCD, ocular and cervical VEMP amplitudes, cervical VEMP thresholds, and air conduction thresholds at 250 Hz are significantly correlated with the surface area of the dehiscence.

Microbial Air Quality and Bacterial Surface Contamination in Ambulances During Patient Services

PubMed Central

Luksamijarulkul, Pipat; Pipitsangjan, Sirikun

2015-01-01

Objectives We sought to assess microbial air quality and bacterial surface contamination on medical instruments and the surrounding areas among 30 ambulance runs during service. Methods We performed a cross-sectional study of 106 air samples collected from 30 ambulances before patient services and 212 air samples collected during patient services to assess the bacterial and fungal counts at the two time points. Additionally, 226 surface swab samples were collected from medical instrument surfaces and the surrounding areas before and after ambulance runs. Groups or genus of isolated bacteria and fungi were preliminarily identified by Gram’s stain and lactophenol cotton blue. Data were analyzed using descriptive statistics, t-test, and Pearson’s correlation coefficient with a p-value of less than 0.050 considered significant. Results The mean and standard deviation of bacterial and fungal counts at the start of ambulance runs were 318±485cfu/m3 and 522±581cfu/m3, respectively. Bacterial counts during patient services were 468±607cfu/m3 and fungal counts were 656±612cfu/m3. Mean bacterial and fungal counts during patient services were significantly higher than those at the start of ambulance runs, p=0.005 and p=0.030, respectively. For surface contamination, the overall bacterial counts before and after patient services were 0.8±0.7cfu/cm2 and 1.3±1.1cfu/cm2, respectively (p<0.001). The predominant isolated bacteria and fungi were Staphylococcus spp. and Aspergillus spp., respectively. Additionally, there was a significantly positive correlation between bacterial (r=0.3, p<0.010) and fungal counts (r=0.2, p=0.020) in air samples and bacterial counts on medical instruments and allocated areas. Conclusions This study revealed high microbial contamination (bacterial and fungal) in ambulance air during services and higher bacterial contamination on medical instrument surfaces and allocated areas after ambulance services compared to the start of ambulance runs. Additionally, bacterial and fungal counts in ambulance air showed a significantly positive correlation with the bacterial surface contamination on medical instruments and allocated areas. Further studies should be conducted to determine the optimal intervention to reduce microbial contamination in the ambulance environment. PMID:25960835

Influence of long-range atmospheric transport pathways and climate teleconnection patterns on the variability of surface 210Pb and 7Be concentrations in southwestern Europe.

PubMed

Grossi, C; Ballester, J; Serrano, I; Galmarini, S; Camacho, A; Curcoll, R; Morguí, J A; Rodò, X; Duch, M A

2016-12-01

The variability of the atmospheric concentration of the 7 Be and 210 Pb radionuclides is strongly linked to the origin of air masses, the strength of their sources and the processes of wet and dry deposition. It has been shown how these processes and their variability are strongly affected by climate change. Thus, a deeper knowledge of the relationship between the atmospheric radionuclides variability measured close to the ground and these atmospheric processes could help in the analysis of climate scenarios. In the present study, we analyze the atmospheric variability of a 14-year time series of 7 Be and 210 Pb in a Mediterranean coastal city using a synergy of different indicators and tools such as: the local meteorological conditions, global and regional climate indexes and a lagrangian atmospheric transport model. We particularly focus on the relationships between the main pathways of air masses and sun spots occurrence, the variability of the local relative humidity and temperature conditions, and the main modes of regional climate variability, such as the North Atlantic Oscillation (NAO) and the Western Mediterranean Oscillation (WeMO). The variability of the observed atmospheric concentrations of both 7 Be and 210 Pb radionuclides was found to be mainly positively associated to the local climate conditions of temperature and to the pathways of air masses arriving at the station. Measured radionuclide concentrations significantly increase when air masses travel at low tropospheric levels from central Europe and the western part of the Iberian Peninsula, while low concentrations are associated with westerly air masses. We found a significant negative correlation between the WeMO index and the atmospheric variability of both radionuclides and no significant association was observed for the NAO index. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bibliography on aircraft fire hazards and safety. Volume 1: Hazards. Part 1: Key numbers 1 to 817

NASA Technical Reports Server (NTRS)

Pelouch, J. J., Jr. (Compiler); Hacker, P. T. (Compiler)

1974-01-01

Ignition temperatures of n-hexane, n-octane, n-decane, JP-6 jet fuel, and aircraft engine oil MIL-7-7808 (0-60-18) were determined in air using heated Pyrex cylinders and Nichrome wires, rods, or tubes. Ignition temperature varied little with fuel-air ratio, but increased as the size of the heat source was decreased. Expressions are given which define the variation of the hot surface ignition temperatures of these combustibles with the radius and the surface area of the heat source. The expressions are applicable to stagnant or low velocity flow conditions (less than 0.2 in./sec.). In addition, the hot gas ignition temperatures of the combustible vapor-air mixtures were determined with jets of hot air. These ignition temperatures also varied little with fuel-air ratio and increased as the diameter of the heat sources was decreased.

The application of ionizers in domestic refrigerators for reduction in airborne and surface bacteria.

PubMed

Kampmann, Y; Klingshirn, A; Kloft, K; Kreyenschmidt, J

2009-12-01

To investigate the antimicrobial effect of ionization on bacteria in household refrigerators. Ionizer prototypes were tested with respect to their technical requirements and their ability to reduce surface and airborne contamination in household refrigerators. Ion and ozone production of the tested prototypes were measured online by an ion meter and an ozone analyser. The produced negative air ion (NAI) and ozone amounts were between 1.2 and 3.7 x 10(6) NAI cm(-3) and 11 and 19 ppb O(3), respectively. To test the influence of ionization on surface contamination, different materials like plastic, glass and nutrient agar for simulation of food were inoculated with bacterial suspensions. The reduction rate was dependent on surface properties. The effect on airborne bacteria was tested by nebulization of Bacillus subtilis- suspension (containing spores) aerosols in refrigerators with and without an ionizer. A clear reduction in air contamination because of ionization was measured. The antimicrobial effect is dependent on several factors, such as surface construction and airflow patterns within the refrigerator. Ionization seems to be an effective method for reduction in surface and airborne bacteria. This study is an initiation for a new consumer tool to decontaminate domestic refrigerators.

JUPITER AS A GIANT COSMIC RAY DETECTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rimmer, P. B.; Stark, C. R.; Helling, Ch., E-mail: pr33@st-andrews.ac.uk

We explore the feasibility of using the atmosphere of Jupiter to detect ultra-high-energy cosmic rays (UHECRs). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmicmore » ray ''detector'' area of 3.3 × 10{sup 7} km{sup 2}. We predict that Fermi-LAT should be able to detect events of energy >10{sup 21} eV with fluence 10{sup –7} erg cm{sup –2} at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays ≳ 10{sup 20} eV. Extensive air showers also produce a synchrotron signature that may be measurable by Atacama Large Millimeter/submillimeter Array (ALMA). Simultaneous observations of Jupiter with ALMA and Fermi-LAT could be used to provide broad constraints on the energies of the initiating cosmic rays.« less

An economic assessment of the health effects and crop yield losses caused by air pollution in mainland China.

PubMed

Miao, Weijie; Huang, Xin; Song, Yu

2017-06-01

Air pollution is severe in China, and pollutants such as PM 2.5 and surface O 3 may cause major damage to human health and crops, respectively. Few studies have considered the health effects of PM 2.5 or the loss of crop yields due to surface O 3 using model-simulated air pollution data in China. We used gridded outputs from the WRF-Chem model, high resolution population data, and crop yield data to evaluate the effects on human health and crop yield in mainland China. Our results showed that outdoor PM 2.5 pollution was responsible for 1.70-1.99 million cases of all-cause mortality in 2006. The economic costs of these health effects were estimated to be 151.1-176.9 billion USD, of which 90% were attributed to mortality. The estimated crop yield losses for wheat, rice, maize, and soybean were approximately 9, 4.6, 0.44, and 0.34 million tons, respectively, resulting in economic losses of 3.4 billion USD. The total economic losses due to ambient air pollution were estimated to be 154.5-180.3 billion USD, accounting for approximately 5.7%-6.6% of the total GDP of China in 2006. Our results show that both population health and staple crop yields in China have been significantly affected by exposure to air pollution. Measures should be taken to reduce emissions, improve air quality, and mitigate the economic loss. Copyright © 2016. Published by Elsevier B.V.

Use of experimentally determined Henry's Law and salting-out constants for ethanol in seawater for determination of the saturation state of ethanol in coastal waters.

PubMed

Willey, Joan D; Powell, Jacqueline P; Avery, G Brooks; Kieber, Robert J; Mead, Ralph N

2017-09-01

The Henry's law constant for ethanol in seawater was experimentally determined to be 221 ± 4 M/atm at 22 °C compared with 247 ± 6 M/atm in pure water. The salting out coefficient for ethanol was 0.13 M -1 . In seawater ln(K H ) = -(12.8 ± 0.7) + (5310 ± 197)/T where K H is in M atm -1 and temperature is in K. This plus the salting out coefficient allow calculation of K H for any estuarine or sea water between 1 and 35 °C. High concentrations of dissolved organic carbon do not affect K H values in fresh or seawater. Nearshore surface waters were usually undersaturated with respect to gas phase ethanol except when air concentrations decreased, whereas surface seawater 40 km from shore was supersaturated. The percent saturation in surface waters is driven primarily by changes in air concentrations because these change quickly (hours) and more extensively than surface water. This study allows calculation of ethanol saturation states from air and surface water concentrations which is a necessary step to define the role of surface oceans in the global biogeochemical cycling of ethanol both now and in the future as use of ethanol biofuel continues to grow. Copyright © 2017 Elsevier Ltd. All rights reserved.

In situ modification of activated carbons developed from a native invasive wood on removal of trace toxic metals from wastewater.

PubMed

de Celis, J; Amadeo, N E; Cukierman, A L

2009-01-15

Activated carbons were developed by phosphoric acid activation of sawdust from Prosopis ruscifolia wood, an indigenous invasive species of degraded lands, at moderate conditions (acid/precursor ratio=2, 450 degrees C, 0.5h). For in situ modification of their characteristics, either a self-generated atmosphere or flowing air was used. The activated carbons developed in the self-generated atmosphere showed higher BET surface area (2281m2/g) and total pore volume (1.7cm3/g) than those obtained under flowing air (1638m2/g and 1.3cm3/g). Conversely, the latter possessed a higher total amount of surface acidic/polar oxygen groups (2.2meq/g) than the former (1.5meq/g). To evaluate their metal sorption capability, adsorption isotherms of Cu(II) ion from model solutions were determined and properly described by the Langmuir model. Maximum sorption capacity (Xm) for the air-derived carbons (Xm=0.44mmol/g) almost duplicated the value for those obtained in the self-generated atmosphere (Xm=0.24mmol/g), pointing to a predominant effect of the surface functionalities on metal sequestering behaviour. The air-derived carbons also demonstrated a superior effectiveness in removing Cd(II) ions as determined from additional assays in equilibrium conditions. Accordingly, effective phosphoric acid-activated carbons from Prosopis wood for toxic metals removal from wastewater may be developed by in situ modification of their characteristics operating under flowing air.

Influence of the aqueous film coating process on the properties and stability of tablets containing a moisture-labile drug.

PubMed

Ruotsalainen, Mirja; Heinämäki, Jyrki; Taipale, Krista; Yliruusi, Jouko

2003-01-01

The effects of an aqueous film coating process on the morphology and storage stability of hydroxypropyl methylcellulose-coated tablets containing a moisture-labile model drug (acetylsalicylic acid, ASA) were evaluated using an instrumented side-vented tablet pan coater. Coating parameters studied were inlet air absolute humidity 5 g/m3 and 12 g/m3, spraying air pressure 100 kPa and 500 kPa, pan air temperature 35 degrees C and 55 degrees C, and coating solution flow rate 2.2 g/min and 7.8 g/min. The surface roughness of the coatings was measured with a laser profilometer and the chemical hydrolysis of the model drug ASA with an UV-spectrophotometer. The film-coated tablets were stored at 25 degrees C/60% RH and 40 degrees C/75% RH for three months. The high absolute humidity of the inlet air increased the residual water content and surface roughness of the coated tablets. Using a lower coating solution flow rate, higher spraying air pressure and pan temperature the coatings were smooth and homogeneous. In both ambient and accelerated storage conditions, the roughness of the coatings and the hydrolysis of ASA increased, but this was independent of the film coating process. Uniform and smooth hydroxypropyl methylcellulose coatings can be achieved by improved control of process parameters related to the application of the coating solution and water evaporation of the tablet surface.

Validation of Nimbus-7 cloud and SMMR data

NASA Technical Reports Server (NTRS)

Hwang, P. H.; Yeh, H. Y. M.; Macmillan, D. S.; Long, C. S.

1986-01-01

The relationship between cloud amount, water content (WC), and liquid water content (LWC) is studied. Nimbus-7 cloud data and LWC and WC data derived from the SMMR for July 1979 are analyzed and compared. The SMMR sea surface temperature (SST) data are also compared to Air Force SST data. The comparisons reveal that Nimbus-7 cloud data and the SMMR WC and LWC data correlate well, and there is also good agreement between the SMMR SST and the Air Force data. The data demonstrate that there is a relation between the WC, LWC, and cloud amount data.

Drop impact on a solid surface at reduced air pressure

NASA Astrophysics Data System (ADS)

Langley, Kenneth; Li, E. Q.; Tian, Y. S.; Hicks, P. D.; Thoroddsen, S. T.

2017-11-01

When a drop approaches a solid surface at atmospheric pressure, the lubrication pressure within the air forms a dimple in the bottom of the drop resulting in the entrainment of an air disc upon impact. Reducing the ambient air pressure below atmospheric has been shown to suppress splashing and the compression of the intervening air could be significant on the air disc formation; however, to date there have been no experimental studies showing how the entrainment of the air disc is affected by reducing the ambient pressure. Using ultra-high-speed interferometry, at up to 5 Mfps, we investigate droplet impacts onto dry solid surfaces in reduced ambient air pressures with particular interest in what happens as rarified gas effects become important, i.e. when the thickness of the air layer is of the same magnitude as the mean free path of the air molecules. Experimental data will be presented showing novel phenomena and comparisons will be drawn with theoretical models from the literature.

Nanoscale mechanochemical wear of phosphate laser glass against a CeO2 particle in humid air

NASA Astrophysics Data System (ADS)

Yu, Jiaxin; He, Hongtu; Zhang, Yafeng; Hu, Hailong

2017-01-01

Using an atomic force microscope, the friction and wear of phosphate laser glass against a CeO2 particle were quantitatively studied both in humid air and in vacuum, to reveal the water molecules induced mechanochemical wear mechanism of phosphate laser glass. The friction coefficient of the glass/CeO2 pair in air was found to be 5-7 times higher than that in vacuum due to the formation of a capillary water bridge at the friction interface, with a contribution of the capillary-related friction to the total friction coefficient as high as 65-79%. The capillary water bridge further induced a serious material removal of glass and CeO2 particle surfaces, while supplying both a local liquid water environment to corrode the glass surface and a high shearing force to assist the stretching of the Cesbnd Osbnd P bond, accelerating the reaction between water and the glass/CeO2 pair. In vacuum, however, no discernable wear phenomena were observed, but the phase images captured by AFM tapping mode suggested the occurrence of potential strain hardening in the friction area of the glass surface.

Measurement and modeling of diel variability of polybrominated diphenyl ethers and chlordanes in air.

PubMed

Moeckel, Claudia; Macleod, Matthew; Hungerbühler, Konrad; Jones, Kevin C

2008-05-01

Short-term variability of concentrations of polybrominated diphenyl ethers (PBDEs) and chlordanes in air at a semirural site in England over a 5 day period is reported. Four-hour air samples were collected during a period dominated by a high pressure system that produced stable diel (24-h) patterns of meteorological conditions such as temperature and atmospheric boundary layer height. PBDE and chlordane concentrations showed clear diel variability with concentrations in the afternoon and evening being 1.9 - 2.7 times higher than in the early morning. The measurements are interpreted using a multimedia mass balance model parametrized with forcing functions representing local temperature, atmospheric boundary layer height, wind speed and hydroxyl radical concentrations. Model results indicate that reversible, temperature-controlled air-surface exchange is the primary driver of the diel concentration pattern observed for chlordanes and PBDE 28. For higher brominated PBDE congeners (47, 99 and 100), the effect of variable atmospheric mixing height in combination with irreversible deposition on aerosol particles is dominant and explains the diel patterns almost entirely. Higher concentrations of chlordanes and PBDEs in air observed at the end of the study period could be related to likely source areas using back trajectory analysis. This is the first study to clearly document diel variability in concentrations of PBDEs in air over a period of several days. Our model analysis indicates that high daytime and low nighttime concentrations of semivolatile organic chemicals can arise from different underlying driving processes, and are not necessarily evidence of reversible air-surface exchange on a 24-h time scale.

A climatology of ⁷Be in surface air in European Union.

PubMed

Hernández-Ceballos, M A; Cinelli, G; Ferrer, M Marín; Tollefsen, T; De Felice, L; Nweke, E; Tognoli, P V; Vanzo, S; De Cort, M

2015-03-01

This study presents a European-wide analysis of the spatial and temporal distribution of the cosmogenic isotope (7)Be in surface air. This is the first time that a long term database of 34 sampling sites that regularly provide data to the Radioactivity Environmental Monitoring (REM) network, managed by the Joint Research Centre (JRC) in Ispra, is used. While temporal coverage varies between stations, some of them have delivered data more or less continuously from 1984 to 2011. The station locations were considerably heterogeneous, both in terms of latitude and altitude, a range which should ensure a high degree of representativeness of the results. The mean values of (7)Be activity concentration presented a spatial distribution value ranging from 2.0 to 5.4 mBq/m(3) over the European Union. The results of the ANOVA analysis of all (7)Be data available indicated that its temporal and spatial distributions were mainly explained by the location and characteristic of the sampling sites rather than its temporal distribution (yearly, seasonal and monthly). Higher (7)Be concentrations were registered at the middle, compared to high-latitude, regions. However, there was no correlation with altitude, since all stations are sited within the atmospheric boundary layer. In addition, the total and yearly analyses of the data indicated a dynamic range of (7)Be activity for each solar cycle and phase (maximum or minimum), different impact on stations having been observed according to their location. Finally, the results indicated a significant seasonal and monthly variation for (7)Be activity concentration across the European Union, with maximum concentrations occurring in the summer and minimum in the winter, although with differences in the values reached. The knowledge of the horizontal and vertical distribution of this natural radionuclide in the atmosphere is a key parameter for modelling studies of atmospheric processes, which are important phenomena to be taken into account in the case of a nuclear accident. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

75 FR 53353 - New Postal Product

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-31

... Agreement governs rates for Inbound Air Parcel Post (Air CP), Surface Parcel Post (Surface CP) and Express... CP and EMS, as well as ancillary services. Id. at 3. The Postal Service asserts that this product.... 43 that Surface CP at Non-UPU Rates, EMS and Air CP be considered competitive products. Id. The...

City ventilation of Hong Kong at no-wind conditions

NASA Astrophysics Data System (ADS)

Yang, Lina; Li, Yuguo

We hypothesize that city ventilation due to both thermally-driven mountain slope flows and building surface flows is important in removing ambient airborne pollutants in the high-rise dense city Hong Kong at no-wind conditions. Both spatial and temporal urban surface temperature profiles are an important boundary condition for studying city ventilation by thermal buoyancy. Field measurements were carried out to investigate the diurnal thermal behavior of urban surfaces (mountain slopes, and building exterior walls and roofs) in Hong Kong by using the infrared thermography. The maximum urban surface temperature was measured in the early noon hours (14:00-15:00 h) and the minimum temperature was observed just before sunrise (5:00 h). The vertical surface temperature of the building exterior wall was found to increase with height at daytime and the opposite occurred at nighttime. The solar radiation and the physical properties of the various urban surfaces were found to be important factors affecting the surface thermal behaviors. The temperature difference between the measured maximum and minimum surface temperatures of the four selected exterior walls can be at the highest of 16.7 °C in the early afternoon hours (15:00 h). Based on the measured surface temperatures, the ventilation rate due to thermal buoyancy-induced wall surface flows of buildings and mountain slope winds were estimated through an integral analysis of the natural convection flow over a flat surface. At no-wind conditions, the total air change rate by the building wall flows (2-4 ACH) was found to be 2-4 times greater than that by the slope flows due to mountain surface (1 ACH) due to larger building exterior surface areas and temperature differences with surrounding air. The results provide useful insights into the ventilation of a high-rise dense city at no-wind conditions.

40 CFR Appendix A to Subpart M of... - Interpretive Rule Governing Roof Removal Operations

Code of Federal Regulations, 2010 CFR

2010-07-01

...)). 3.B.3. An exemption from wetting is also allowed when the air or roof surface temperature at the point of wetting is below freezing, as specified in § 61.145(c)(7). If freezing temperatures are indicated as the reason for not wetting, records must be kept of the temperature at the beginning, middle...

Navy Shipboard Lasers for Surface, Air, and Missile Defense: Background and Issues for Congress

DTIC Science & Technology

2013-03-14

absorption and turbulence , suitable for use to evaluate notional maritime beam director subsystems, and shall include studies in adaptive optics for...is good enough in terms of atmospheric transmission to permit the laser to disable targets of interest at tactically useful ranges, and that...Countering Targets ........................................................ 7 Types of Lasers Being Developed for Potential Shipboard Use

Molecular recognition of 7-(2-octadecyloxycarbonylethyl)guanine to cytidine at the air/water interface and LB film studied by Fourier transform infrared spectroscopy.

PubMed

Miao, Wangen; Luo, Xuzhong; Liang, Yingqiu

2003-03-15

Monolayer behavior of a nucleolipid amphiphile, 7-(2-octadecyloxycarbonylethyl)guanine (ODCG), on aqueous cytidine solution was investigated by means of surface-molecular area (pi-A) isotherms. It indicates that molecular recognition by hydrogen bonding is present between ODCG monolayer and the cytidine in subphase. The Fourier transform infrared (FTIR) transmission spectroscopic result indicates that the cytidine molecules in the subphase can be transferred onto solid substrates by Langmuir-Blodgett (LB) technique as a result of the formation of Watson-Crick base-pairing at the air/water interface. Investigation by rotating polarized FTIR transmission also suggests that the headgroup recognition of this amphiphile to the dissolved cytidine influence the orientation of the tailchains. Copyright 2002 Elsevier Science B.V.

49 CFR 1105.7 - Environmental reports.

Code of Federal Regulations, 2014 CFR

2014-10-01

... energy, noise and air impacts in §§ 1105.7(e)(4), (5), or (6) are met. (vi) Describe the effects... Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... or discontinuance, the applicant must serve copies of the Environmental Report on: (1) The State...

49 CFR 1105.7 - Environmental reports.

Code of Federal Regulations, 2013 CFR

2013-10-01

... energy, noise and air impacts in §§ 1105.7(e)(4), (5), or (6) are met. (vi) Describe the effects... Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... or discontinuance, the applicant must serve copies of the Environmental Report on: (1) The State...

49 CFR 1105.7 - Environmental reports.

Code of Federal Regulations, 2012 CFR

2012-10-01

... energy, noise and air impacts in §§ 1105.7(e)(4), (5), or (6) are met. (vi) Describe the effects... Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... or discontinuance, the applicant must serve copies of the Environmental Report on: (1) The State...

14 CFR 125.225 - Flight data recorders.

Code of Federal Regulations, 2014 CFR

2014-01-01

... acceleration; (5) Heading; (6) Time of each radio transmission to or from air traffic control; (7) Pitch attitude; (8) Roll attitude; (9) Longitudinal acceleration; (10) Control column or pitch control surface... control; (7) Pitch attitude; (8) Roll attitude; (9) Longitudinal acceleration; (10) Pitch trim position...

Generation of large-area and glow-like surface discharge in atmospheric pressure air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Ying; Bi, Zhenhua; Wang, Xueyang

2016-08-15

A large-area (6 cm × 6 cm) air surface dielectric barrier discharge has been generated at atmospheric pressure by using well-aligned and micron-sized dielectric tubes with tungsten wire electrodes. Intensified CCD images with an exposure time of 5 ns show that the uniform surface air discharge can be generated during the rising and falling time of pulsed DC voltage. Current and voltage and optical measurements confirm the formation of glow-like air discharges on the surface of micron-sized dielectric tubes. Simulation results indicate that the microelectrode configuration contributes to the formation of strong surface electric field and plays an important role in the generation of uniformmore » surface air discharge.« less

Improved recovery of Listeria monocytogenes from stainless steel and polytetrafluoroethylene surfaces using air/water ablation.

PubMed

Gião, M S; Blanc, S; Porta, S; Belenguer, J; Keevil, C W

2015-07-01

To develop a gentle ablation technique to recover Listeria monocytogenes biofilms from stainless steel (SS) and polytetrafluoroethylene (PTFE) surfaces by using compressed air and water injection. Biofilms were grown for 4, 24 and 48 h or 7 days and a compressed air and water flow at 2, 3 and 4 bars was applied for cell removal. Collected cells were quantified for total/dead by staining with SYTO 9/PI double staining and cultivable populations were determined by plating onto brain heart infusion (BHI) agar, while coupon surfaces also were stained with DAPI to quantify in situ the remaining cells. The recovery efficiency was compared to that of conventional swabbing. Results showed that the air/water ablation is able to collect up to 98·6% of cells from SS surfaces while swabbing only recovered 11·2% of biofilm. Moreover, air/water ablation recovered 99·9% of cells from PTFE surfaces. The high recovery rate achieved by this technique, along with the fact that cells were able to retain membrane integrity and cultivability, indicate that this device is suitable for the gentle recovery of viable L. monocytogenes biofilm cells. This work presents a highly efficient technique to remove, collect and quantify L. monocytogenes from surfaces commonly used in the food industry, which can thus serve as an important aid in verifying cleaning and sanitation as well as in reducing the likelihood of cross-contamination events. © 2015 The Society for Applied Microbiology.

Fractography evolution in accelerated aging of UHMWPE after gamma irradiation in air.

PubMed

Medel, F; Gómez-Barrena, E; García-Alvarez, F; Ríos, R; Gracia-Villa, L; Puértolas, J A

2004-01-01

We studied the fracture surface evolution of ultra high molecular weight polyethylene (UHMWPE) specimens, manufactured from GUR 1050 compression moulded sheets, after gamma sterilisation in air followed by different aging times after thermal treatment at 120 degrees C. Degradation profiles were obtained by FTIR and DSC measurements after 0, 7, 14, 24 and 36h aging. We observed by SEM the morphology patterns at these aging times, in surface fractographies after uniaxial tensile test of standardised samples. The results pointed out clear differences between short and long aging times. At shorter times, 7h, the behaviour was similar to non-degraded UHMWPE, exhibiting ductile behaviour. At longer times, 24-36h, this thermal protocol provided a highly degraded zone in the subsurface, similar to the white band found after gamma irradiation in air followed by natural aging, although closer to the surface, at 150-200mum. The microstructure of this oxidation zone, similarly found in gamma irradiated samples shelf-aged for 6-7 years, although with different distribution of microvoids, was formed by fibrils, associated with embrittlement of the oxidised UHMWPE. In addition, the evolution of the oxidation index, the enthalpy content, the mechanical parameters, and the depth of the oxidation front deduced from the fractographies versus aging time showed that a changing behaviour in the degradation rate appeared at intermediate aging times.

Effect of atmosphere on the surface tension and viscosity of molten LiNbO 3 measured using the surface laser-light scattering method

NASA Astrophysics Data System (ADS)

Nagasaka, Yuji; Kobayashi, Yusuke

2007-09-01

The surface tension and the viscosity of molten LiNbO 3 (LN) having the congruent composition have been measured simultaneously in a temperature range from 1537 to 1756 K under argon gas and dry-air atmospheres. The present measurement technique involves surface laser-light scattering (SLLS) that detects nanometer-order-amplitude surface waves usually regarded as ripplons excited by thermal fluctuations. This technique's non-invasive nature allows it to avoid the experimental difficulties of conventional techniques resulting from the insertion of an actuator in the melt. The results of surface tension measurement obtained under a dry-air atmosphere are about 5% smaller than those obtained under an argon atmosphere near the melting temperature, and the temperature dependence of the surface tension under a dry-air atmosphere is twice that under an argon atmosphere. The uncertainty of surface tension measurement is estimated to be ±2.6% under argon and ±1.9% under dry air. The temperature dependence of viscosity can be well correlated with the results of Arrhenius-type equations without any anomalous behavior near the melting point. The viscosities obtained under a dry-air atmosphere were slightly smaller than those obtained under an argon atmosphere. The uncertainty of viscosity measurement is estimated to be ±11.1% for argon and ±14.3% for dry air. Moreover, we observed the real-time dynamic behavior of the surface tension and the viscosity of molten LN in response to argon and dry-air atmospheres.

Factors affecting the 7Be surface concentration and its extremely high occurrences over the Scandinavian Peninsula during autumn and winter.

PubMed

Ajtić, J; Brattich, E; Sarvan, D; Djurdjevic, V; Hernández-Ceballos, M A

2018-05-01

Relationships between the beryllium-7 activity concentrations in surface air and meteorological parameters (temperature, atmospheric pressure, and precipitation), teleconnection indices (Arctic Oscillation, North Atlantic Oscillation, and Scandinavian pattern) and number of sunspots are investigated using two multivariate statistical techniques: hierarchical cluster and factor analysis. The beryllium-7 surface measurements over 1995-2011, at four sampling sites located in the Scandinavian Peninsula, are obtained from the Radioactivity Environmental Monitoring Database. In all sites, the statistical analyses show that the beryllium-7 concentrations are strongly linked to temperature. Although the beryllium-7 surface concentration exhibits the well-characterised spring/summer maximum, our study shows that extremely high beryllium-7 concentrations, defined as the values exceeding the 90 th percentile in the data records for each site, also occur over the October-March period. Two types of autumn/winter extremes are distinguished: type-1 when the number of extremes in a given month is less than three, and type-2 when at least three extremes occur in a month. Factor analysis performed for these autumn/winter events shows a weaker effect of temperature and a stronger impact of the transport and production signal on the beryllium-7 concentrations. Further, the majority of the type-2 extremes are associated with a very high monthly Scandinavian teleconnection index. The type-2 extremes that occurred in January, February and March are also linked to sudden stratospheric warmings of the Arctic vortex. Our results indicate that the Scandinavian teleconnection index might be a good indicator of the meteorological conditions facilitating extremely high beryllium-7 surface concentrations over Scandinavia during autumn and winter. Copyright © 2018 Elsevier Ltd. All rights reserved.

Diffusion of volatile organics through porous snow: impact of surface adsorption and grain boundaries

NASA Astrophysics Data System (ADS)

Bartels-Rausch, T.; Wren, S. N.; Schreiber, S.; Riche, F.; Schneebeli, M.; Ammann, M.

2013-03-01

Release of trace gases from surface snow on Earth drives atmospheric chemistry, especially in the polar regions. The gas-phase diffusion of methanol and of acetone through the interstitial air of snow was investigated in a well-controlled laboratory study in the temperature range of 223 to 263 K. The aim of this study was to evaluate how the structure of the snowpack, the interaction of the trace gases with the snow surface, and the grain boundaries influence the diffusion on timescales up to 1 h. The diffusive loss of these two volatile organics into packed snow samples was measured using a chemical ionization mass spectrometer. The structure of the snow was analyzed by means of X-ray computed micro-tomography. The observed diffusion profiles could be well described based on gas-phase diffusion and the known structure of the snow sample at temperatures ≥ 253 K. At colder temperatures surface interactions start to dominate the diffusive transport. Parameterizing these interactions in terms of adsorption to the solid ice surface, i.e. using temperature dependent air-ice partitioning coefficients, better described the observed diffusion profiles than the use of air-liquid partitioning coefficients. No changes in the diffusive fluxes were observed by increasing the number of grain boundaries in the snow sample by a factor of 7, indicating that for these volatile organic trace gases, uptake into grain boundaries does not play a role on the timescale of diffusion through porous surface snow. In conclusion, we have shown that the diffusivity can be predicted when the structure of the snowpack and the partitioning of the trace gas to solid ice is known.

A Sensitivity Analysis of the Impact of Rain on Regional and Global Sea-Air Fluxes of CO2

PubMed Central

Shutler, J. D.; Land, P. E.; Woolf, D. K.; Quartly, G. D.

2016-01-01

The global oceans are considered a major sink of atmospheric carbon dioxide (CO2). Rain is known to alter the physical and chemical conditions at the sea surface, and thus influence the transfer of CO2 between the ocean and atmosphere. It can influence gas exchange through enhanced gas transfer velocity, the direct export of carbon from the atmosphere to the ocean, by altering the sea skin temperature, and through surface layer dilution. However, to date, very few studies quantifying these effects on global net sea-air fluxes exist. Here, we include terms for the enhanced gas transfer velocity and the direct export of carbon in calculations of the global net sea-air fluxes, using a 7-year time series of monthly global climate quality satellite remote sensing observations, model and in-situ data. The use of a non-linear relationship between the effects of rain and wind significantly reduces the estimated impact of rain-induced surface turbulence on the rate of sea-air gas transfer, when compared to a linear relationship. Nevertheless, globally, the rain enhanced gas transfer and rain induced direct export increase the estimated annual oceanic integrated net sink of CO2 by up to 6%. Regionally, the variations can be larger, with rain increasing the estimated annual net sink in the Pacific Ocean by up to 15% and altering monthly net flux by > ± 50%. Based on these analyses, the impacts of rain should be included in the uncertainty analysis of studies that estimate net sea-air fluxes of CO2 as the rain can have a considerable impact, dependent upon the region and timescale. PMID:27673683

Cold air plasma to decontaminate inanimate surfaces of the hospital environment.

PubMed

Cahill, Orla J; Claro, Tânia; O'Connor, Niall; Cafolla, Anthony A; Stevens, Niall T; Daniels, Stephen; Humphreys, Hilary

2014-03-01

The hospital environment harbors bacteria that may cause health care-associated infections. Microorganisms, such as multiresistant bacteria, can spread around the patient's inanimate environment. Some recently introduced biodecontamination approaches in hospitals have significant limitations due to the toxic nature of the gases and the length of time required for aeration. This study evaluated the in vitro use of cold air plasma as an efficient alternative to traditional methods of biodecontamination of hospital surfaces. Cultures of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli, and Acinetobacter baumannii were applied to different materials similar to those found in the hospital environment. Artificially contaminated sections of marmoleum, mattress, polypropylene, powder-coated mild steel, and stainless steel were then exposed to a cold air pressure plasma single jet for 30 s, 60 s, and 90 s, operating at approximately 25 W and 12 liters/min flow rate. Direct plasma exposure successfully reduced the bacterial load by log 3 for MRSA, log 2.7 for VRE, log 2 for ESBL-producing E. coli, and log 1.7 for A. baumannii. The present report confirms the efficient antibacterial activity of a cold air plasma single-jet plume on nosocomial bacterially contaminated surfaces over a short period of time and highlights its potential for routine biodecontamination in the clinical environment.

Digitisation of Historical Observations for ERA-CLIM

NASA Astrophysics Data System (ADS)

Stickler, A.; Brönnimann, S.; Valente, M. A.; Sterin, A.; Jourdain, S.; Guzman, J.; Allan, R.; Dee, D.

2012-04-01

Aside from improvements in the assimilation and numerical modelling schemes, new reanalyses can significantly profit from the recovery, imaging and digitisation of historical observations. Here, we present the status and selected examples of the digitisation of historical surface, aerological and radiation measurements in the framework of ERA-CLIM, an EU FP7 project designed to prepare the data necessary for a new reanalysis going back to the beginning of the 20th century. One peculiarity of this reanalysis is the fact that it will, for the first time, assimilate upper-air data from the time before 1948. The data rescue activities of ERA-CLIM specifically focus on the data-sparse regions, such as the Tropics, the polar regions and the world's oceans before 1957. From the time before 1957, large amounts of surface data from former colonies and from overseas territories of European countries (e.g. Portugal and France) are being digitised. These surface data make up ca. 55% of the estimated total station days that have been inventorised. Another 45% of the inventorised data consist of upper-air (aerological) observations. A relatively tiny fraction (< 1%) are atmospheric transmission measurements from 13 stations worldwide (1902-50). In case of the very early upper-air observations before the 1930s, even Europe and North America still hold an important quantity of data to be recovered in digital form. The inventory of all identified data sources and their digital imaging have almost been completed. The digitisation is still ongoing and will partly be continued for some time. However, due to the vast amount of records identified and the large amount of data, especially in the case of upper-air (1638 inventory entries, 1.3 mio. station days) and surface data (1.55 mio. station days), a prioritisation in agreement with the goals and deliverables of the project turned out to be necessary. The largest single sources of upper-air data found were the NOAA Central Library Foreign Data section (27%, data from many countries) and Indian upper-air and weather bulletins (27%), followed by many smaller sources, each making up less than 5% of the total amount of data. For the whole project, 16% of the upper-air data inventory entries stem from aircraft, registering balloon, kite or captive balloon measurements, 25% from radiosondes, and the largest part, 60%, are pilot balloon wind observations. Quality control and reformatting of the data have started and will soon be finished so that the first version of the data can be delivered on time in June.

Chemical nature of the barrier in Pb/YBa2Cu3O(7-x) tunneling structures

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Foote, M. C.; Hunt, B. D.; Bajuk, L.

1991-01-01

Several reports of reproducible tunneling measurements on YBa2Cu3O(7-x) thin films or single crystals with a Pb counterelectrode have recently appeared. The nature of the tunnel barrier, formed by air exposure, in these structures has been unknown. In the present work, the chemical nature of the tunnel barrier is studied with X-ray photoelectron spectroscopy (XPS). Laser-ablated films grown on LaAlO3 which have been chemically etched and heated in air are found to form nonsuperconducting surface Ba species, evident in an increase of the high binding energy Ba 3d and O 1s signals. A deposited Pb film about 10 A thick is found to be oxidized, and Cu(+2) is partially reduced to Cu(+1). The tunneling barrier thus appears to consist of species resulting from a combination of the air exposure and a reaction between the superconductor and the deposited Pb counterelectrode.

Numerical investigation of the interaction of positive streamers with bubbles floating on a liquid surface

NASA Astrophysics Data System (ADS)

Babaeva, Natalia Yu.; Naidis, George V.; Kushner, Mark J.

2016-09-01

Streamer discharges in air intersecting with liquids are being investigated to produce reactivity in the liquid. In this talk, we discuss results from a 2-d computational investigation of streamers in air intersecting an isolated liquid, air filled bubble floating on a liquid surface. The 15 mm diameter bubble is conducting water (ɛ /ɛ0 = 80 , σ = 7 . 5 ×10-4Ω-1cm-1) or transformer oil (ɛ /ɛ0 = 2 . 2 , σ = 1 . 5 ×10-13Ω-1cm-1). A needle electrode is positioned d =0-10 mm from the bubble center. With a water bubble (d =0) the streamer slides along the external surface but does not penetrate the bubble due to electric field screening by the conducting shell. If the electrode is shifted (d =3-10 mm) the streamer deviates from the vertical and adheres to the bubble. If the electrode is inserted inside the bubble, the streamer path depends on how deep the electrode penetrates. For shallow penetration, the streamer propagates along the inner surface of the bubble. For deep penetration the streamer takes the shortest path down through the gas. Due to the low conductivity of the oil bubble shell the electric field penetrates into the interior of the bubble. The streamer can then be re-initiated inside the bubble. Charge accumulation on both sides of the bubble shell and perforation of the shell will be also discussed. NYB, GVN supported by Russian Sci. Found. (14-12-01295). MJK by US Natl. Sci. Found. and Dept. of Energy.

Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Michael J.; Go, David B., E-mail: dgo@nd.edu; Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indianapolis 46556

To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ∼30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like dischargesmore » on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.« less

Thermal imaging for cold air flow visualisation and analysis

NASA Astrophysics Data System (ADS)

Grudzielanek, M.; Pflitsch, A.; Cermak, J.

2012-04-01

In this work we present first applications of a thermal imaging system for animated visualization and analysis of cold air flow in field studies. The development of mobile thermal imaging systems advanced very fast in the last decades. The surface temperature of objects, which is detected with long-wave infrared radiation, affords conclusions in different problems of research. Modern thermal imaging systems allow infrared picture-sequences and a following data analysis; the systems are not exclusive imaging methods like in the past. Thus, the monitoring and analysing of dynamic processes became possible. We measured the cold air flow on a sloping grassland area with standard methods (sonic anemometers and temperature loggers) plus a thermal imaging system measuring in the range from 7.5 to 14µm. To analyse the cold air with the thermal measurements, we collected the surface infrared temperatures at a projection screen, which was located in cold air flow direction, opposite the infrared (IR) camera. The intention of using a thermal imaging system for our work was: 1. to get a general idea of practicability in our problem, 2. to assess the value of the extensive and more detailed data sets and 3. to optimise visualisation. The results were very promising. Through the possibility of generating time-lapse movies of the image sequences in time scaling, processes of cold air flow, like flow waves, turbulence and general flow speed, can be directly identified. Vertical temperature gradients and near-ground inversions can be visualised very well. Time-lapse movies will be presented. The extensive data collection permits a higher spatial resolution of the data than standard methods, so that cold air flow attributes can be explored in much more detail. Time series are extracted from the IR data series, analysed statistically, and compared to data obtained using traditional systems. Finally, we assess the usefulness of the additional measurement of cold air flow with thermal imaging systems.

Preparation of Water-Repellent Glass by Sol-Gel Process Using Perfluoroalkylsilane and Tetraethoxysilane.

PubMed

Jeong, Hye-Jeong; Kim, Dong-Kwon; Lee, Soo-Bok; Kwon, Soo-Han; Kadono, Kohei

2001-03-01

Coating films on glass substrate were prepared by sol-gel process using alkoxide solutions containing perfluoroalkylsilane (PFAS) and tetraethoxysilane (TEOS). The physical properties of the coating films were characterized by SEM, FT-IR, and XRD. And their surface properties were investigated by measuring contact angles and atomic compositions. Transparent coating films with smooth surface and uniform thickness could be obtained. The contact angles of the coating films for water and methylene iodide are extremely high, at 118 degrees and 97 degrees, respectively, and their surface free energies are about 9.7 dyn/cm. It was found that the water-repellent glass prepared is very hydrophobic and exhibits excellent water-repellency. Hydrophobic perfluoroalkyl groups are preferentially enriched to the outermost layer at the coating film-air interface, and two layers probably exist in the coating film. The upper layer oriented toward the air is composed of mainly perfluoroalkyl groups originating from PFAS, and the lower layer is composed of mainly -OSiO- groups originating from TEOS. The heat treatment after drying step cannot influence the surface enrichment of the perfluoroalkyl group. The hydrolysis reaction should be more completely done before the dip coating step to obtain lower surface free energy. The burning temperature should be less than 300 degrees C because the perfluoroalkyl group begins to decompose from this temperature. Copyright 2001 Academic Press.

Heterotrophic bacteria in an air-handling system.

PubMed Central

Hugenholtz, P; Fuerst, J A

1992-01-01

Heterotrophic bacteria from structural surfaces, drain pan water, and the airstream of a well-maintained air-handling system with no reported building-related illness were enumerated. Visually the system appeared clean, but large populations of bacteria were found on the fin surface of the supply-side cooling coils (10(5) to 10(6) CFU cm-2), in drain pan water (10(5) to 10(7) CFU ml-1), and in the sump water of the evaporative condenser (10(5) CFU ml-1). Representative bacterial colony types recovered from heterotrophic plate count cultures on R2A medium were identified to the genus level. Budding bacteria belonging to the genus Blastobacter dominated the supply surface of the coil fins, the drain pan water, and the postcoil air. These data and independent scanning electron microscopy indicated that a resident population of predominantly Blastobacter bacteria was present as a biofilm on the supply-side cooling coil fins. Images PMID:1476435

Heterotrophic bacteria in an air-handling system.

PubMed

Hugenholtz, P; Fuerst, J A

1992-12-01

Heterotrophic bacteria from structural surfaces, drain pan water, and the airstream of a well-maintained air-handling system with no reported building-related illness were enumerated. Visually the system appeared clean, but large populations of bacteria were found on the fin surface of the supply-side cooling coils (10(5) to 10(6) CFU cm-2), in drain pan water (10(5) to 10(7) CFU ml-1), and in the sump water of the evaporative condenser (10(5) CFU ml-1). Representative bacterial colony types recovered from heterotrophic plate count cultures on R2A medium were identified to the genus level. Budding bacteria belonging to the genus Blastobacter dominated the supply surface of the coil fins, the drain pan water, and the postcoil air. These data and independent scanning electron microscopy indicated that a resident population of predominantly Blastobacter bacteria was present as a biofilm on the supply-side cooling coil fins.

Hybrid surface design for robust superhydrophobicity.

PubMed

Dash, Susmita; Alt, Marie T; Garimella, Suresh V

2012-06-26

Surfaces may be rendered superhydrophobic by engineering the surface morphology to control the extent of the liquid-air interface and by the use of low-surface-energy coatings. The droplet state on a superhydrophobic surface under static and dynamic conditions may be explained in terms of the relative magnitudes of the wetting and antiwetting pressures acting at the liquid-air interface on the substrate. In this paper, we discuss the design and fabrication of hollow hybrid superhydrophobic surfaces which incorporate both communicating and noncommunicating air gaps. The surface design is analytically shown to exhibit higher capillary (or nonwetting) pressure compared to solid pillars with only communicating air gaps. Six hybrid surfaces are fabricated with different surface parameters selected such that the Cassie state of a droplet is energetically favorable. The robustness of the surfaces is tested under dynamic impingement conditions, and droplet dynamics are explained using pressure-based transitions between Cassie and Wenzel states. During droplet impingement, the effective water hammer pressure acting due to the sudden change in the velocity of the droplet is determined experimentally and is found to be at least 2 orders of magnitude less than values reported in the literature. The experiments show that the water hammer pressure depends on the surface morphology and capillary pressure of the surface. We propose that the observed reduction in shock pressure may be attributed to the presence of air gaps in the substrate. This feature allows liquid deformation and hence avoids the sudden stoppage of the droplet motion as opposed to droplet behavior on smooth surfaces.

Effects of Chemistry on Blunt-Body Wake Structure

NASA Technical Reports Server (NTRS)

Dogra, Virendra K.; Moss, James N.; Wilmoth, Richard G.; Taylor, Jeff C.; Hassan, H. A.

1995-01-01

Results of a numerical study are presented for hypersonic low-density flow about a 70-deg blunt cone using direct simulation Monte Carlo (DSMC) and Navier-Stokes calculations. Particular emphasis is given to the effects of chemistry on the near-wake structure and on the surface quantities and the comparison of the DSMC results with the Navier-Stokes calculations. The flow conditions simulated are those experienced by a space vehicle at an altitude of 85 km and a velocity of 7 km/s during Earth entry. A steady vortex forms in the near wake for these freestream conditions for both chemically reactive and nonreactive air gas models. The size (axial length) of the vortex for the reactive air calculations is 25% larger than that of the nonreactive air calculations. The forebody surface quantities are less sensitive to the chemistry than the base surface quantities. The presence of the afterbody has no effect on the forebody flow structure or the surface quantities. The comparisons of DSMC and Navier-Stokes calculations show good agreement for the wake structure and the forebody surface quantities.

Experimental investigation of turbulent wall jet

NASA Astrophysics Data System (ADS)

Andre, Matthieu A.; Bardet, Philippe M.

2011-11-01

Water jet flowing on a flat plate surrounded by quiescent air constitutes a standard case for the study of the interaction between turbulence and the liquid-air interface. This is of particular interest in the understanding of heat and mass transfers across interfaces. The structure of the surface has a great influence on the rate of the transfers which is critical for chemical processes like separation or absorption; pool-type nuclear reactor; climate modeling etc. This study focuses on high Froude (8 to 12) and Weber (3300 to 7400) numbers at which the surface exhibits small wavelength and large amplitude deformations, such as ligaments, surface break up with air entrainment and droplets projection. The experiment features a high velocity (up to 7.5 m/s) water wall jet (19.05mm thick at the nozzle exit) flowing on a flat plate (Re =105 to 1 . 5 .105). High speed movies and PLIF visualization show the evolution of the surface from smooth to 2D structures, then 3D disturbances as the turbulence arising from the wall interacts with the surface.

Nonthermal inactivation of norovirus surrogates on blueberries using atmospheric cold plasma.

PubMed

Lacombe, Alison; Niemira, Brendan A; Gurtler, Joshua B; Sites, Joseph; Boyd, Glenn; Kingsley, David H; Li, Xinhui; Chen, Haiqiang

2017-05-01

Viruses are currently the leading cause of foodborne outbreaks, most of which are associated with foods consumed raw. Cold plasma (CP) is an emerging novel nonthermal technology that can be used to surface decontaminate foods. This study investigated CP technology for the nonthermal inactivation of human norovirus surrogates, Tulane virus (TV) and murine norovirus (MNV), on the surface of blueberries. Blueberries (5 g) were weighed into sterile 4 oz. glass jars and inoculated with TV, 5 log PFU/g. Samples were treated with atmospheric CP for 0, 15, 30, 45, and 60 s at a working distance of 7.5 cm with 4 cubic feet/minute (cfm) of CP jet. Temperature readings were taken with an infrared camera prior to, and immediately following, CP treatments. In order to establish the impact of air flow during CP treatment (4 cfm), an additional 7 cfm jet of room temperature air was introduced from a separate nozzle. The experiment was repeated with 90 and 120 s as additional treatment time points. Viral titers were measured immediately after each treatment with a plaque assay using LLC-MK2 cells (TV) or RAW 264.7 cells (MNV). TV was significantly reduced 1.5 PFU/g compared to the control after treatment time of 45s, which was achieved regardless of temperature conditions. With the addition of 7 cfm of ambient air, the maximum log reduction for TV was 3.5 log PFU/g after 120s of treatment. MNV was significantly reduced by 0.5 log PFU/g compare to the control at 15s, and further treatment of MNV with ambient air brought the log reduction to greater than 5 log PFU/g at 90 s of treatment (Fig. 3). These results demonstrate that CP viral inactivation does not rely on thermal inactivation, and is therefore nonthermal in nature. With further optimization, CP may be used by food processors as a means of nonthermal inactivation of foodborne viruses. Published by Elsevier Ltd.

Detection and Identification: Instrumentation and Calibration for Air/Liquid/Surface-borne Nanoscale Particles

NASA Astrophysics Data System (ADS)

Ling, Tsz Yan; Zuo, Zhili; Pui, David Y. H.

2013-04-01

Nanoscale particles can be found in the air-borne, liquid-borne and surface-borne dispersed phases. Measurement techniques for nanoscale particles in all three dispersed phases are needed for the environmental, health and safety studies of nanomaterials. We present our studies on connecting the nanoparticle measurements in different phases to enhance the characterization capability. Microscopy analysis for particle morphology can be performed by depositing air-borne or liquid-borne nanoparticles on surfaces. Detection limit and measurement resolution of the liquid-borne nanoparticles can be enhanced by aerosolizing them and taking advantage of the well-developed air-borne particle analyzers. Sampling electrically classified air-borne virus particles with a gelatin filter provides higher collection efficiency than a liquid impinger.

Satellite-Surface Perspectives of Air Quality and Aerosol-Cloud Effects on the Environment: An Overview of 7-SEAS BASELInE

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Maring, Hal B.; Lin, Neng-Huei; Buntoung, Sumaman; Chantara, Somporn; Chuang, Hsiao-Chi; Gabriel, Philip M.; Goodloe, Colby S.; Holben, Brent N.; Hsiao, Ta-Chih;

The Impact of Sea Ice Concentration Accuracies on Climate Model Simulations with the GISS GCM

NASA Technical Reports Server (NTRS)

Parkinson, Claire L.; Rind, David; Healy, Richard J.; Martinson, Douglas G.; Zukor, Dorothy J. (Technical Monitor)

2000-01-01

The Goddard Institute for Space Studies global climate model (GISS GCM) is used to examine the sensitivity of the simulated climate to sea ice concentration specifications in the type of simulation done in the Atmospheric Modeling Intercomparison Project (AMIP), with specified oceanic boundary conditions. Results show that sea ice concentration uncertainties of +/- 7% can affect simulated regional temperatures by more than 6 C, and biases in sea ice concentrations of +7% and -7% alter simulated annually averaged global surface air temperatures by -0.10 C and +0.17 C, respectively, over those in the control simulation. The resulting 0.27 C difference in simulated annual global surface air temperatures is reduced by a third, to 0.18 C, when considering instead biases of +4% and -4%. More broadly, least-squares fits through the temperature results of 17 simulations with ice concentration input changes ranging from increases of 50% versus the control simulation to decreases of 50% yield a yearly average global impact of 0.0107 C warming for every 1% ice concentration decrease, i.e., 1.07 C warming for the full +50% to -50% range. Regionally and on a monthly average basis, the differences can be far greater, especially in the polar regions, where wintertime contrasts between the +50% and -50% cases can exceed 30 C. However, few statistically significant effects are found outside the polar latitudes, and temperature effects over the non-polar oceans tend to be under 1 C, due in part to the specification of an unvarying annual cycle of sea surface temperatures. The +/- 7% and 14% results provide bounds on the impact (on GISS GCM simulations making use of satellite data) of satellite-derived ice concentration inaccuracies, +/- 7% being the current estimated average accuracy of satellite retrievals and +/- 4% being the anticipated improved average accuracy for upcoming satellite instruments. Results show that the impact on simulated temperatures of imposed ice concentration changes is least in summer, encouragingly the same season in which the satellite accuracies are thought to be worst. Hence the impact of satellite inaccuracies is probably less than the use of an annually averaged satellite inaccuracy would suggest.

Microgravity Boiling Enhancement Using Vibration-Based Fluidic Technologies

NASA Astrophysics Data System (ADS)

Smith, Marc K.; Glezer, Ari; Heffington, Samuel N.

2002-11-01

Thermal management is an important subsystem in many devices and technologies used in a microgravity environment. The increased power requirements of new Space technologies and missions mean that the capacity and efficiency of thermal management systems must be improved. The current work addresses this need through the investigation and development of a direct liquid immersion heat transfer cell for microgravity applications. The device is based on boiling heat transfer enhanced by two fluidic technologies developed at Georgia Tech. The first of these fluidic technologies, called vibration-induced bubble ejection, is shown in Fig. 1. Here, an air bubble in water is held against a vibrating diaphragm by buoyancy. The vibrations at 440 Hz induce violent oscillations of the air/water interface that can result in small bubbles being ejected from the larger air bubble (Fig. 1a) and, simultaneously, the collapse of the air/water interface against the solid surface (Fig. 1b). Both effects would be useful during a heat transfer process. Bubble ejection would force vapor bubbles back into the cooler liquid so that they can condense. Interfacial collapse would tend to keep the hot surface wet thereby increasing liquid evaporation and heat transfer to the bulk liquid. Figure 2 shows the effect of vibrating the solid surface at 7.6 kHz. Here, small-scale capillary waves appear on the surface of the bubble near the attachment point on the solid surface (the grainy region). The vibration produces a net force on the bubble that pushes it away from the solid surface. As a result, the bubble detaches from the solid and is propelled into the bulk liquid. This force works against buoyancy and so it would be even more effective in a microgravity environment. The benefit of the force in a boiling process would be to push vapor bubbles off the solid surface, thus helping to keep the solid surface wet and increasing the heat transfer. The second fluidic technology to be employed in this work is a synthetic jet, shown schematically in Fig. 3. The jet is produced using a small, sealed cavity with a sharp-edged orifice on one side and a vibrating diaphragm on the opposite side. The jet is formed when fluid is alternately sucked into and then expelled from the cavity by the motion of the diaphragm. This alternating motion means that there is no net mass addition to the system. Thus, there is no need for input piping or complex fluidic packaging.

Air-sea exchange of gaseous mercury in the tropical coast (Luhuitou fringing reef) of the South China Sea, the Hainan Island, China.

PubMed

Ci, Zhijia; Zhang, Xiaoshan; Wang, Zhangwei

2016-06-01

The air-sea exchange of gaseous mercury (mainly Hg(0)) in the tropical ocean is an important part of the global Hg biogeochemical cycle, but the related investigations are limited. In this study, we simultaneously measured Hg(0) concentrations in surface waters and overlaying air in the tropical coast (Luhuitou fringing reef) of the South China Sea (SCS), Hainan Island, China, for 13 days on January-February 2015. The purpose of this study was to explore the temporal variation of Hg(0) concentrations in air and surface waters, estimate the air-sea Hg(0) flux, and reveal their influencing factors in the tropical coastal environment. The mean concentrations (±SD) of Hg(0) in air and total Hg (THg) in waters were 2.34 ± 0.26 ng m(-3) and 1.40 ± 0.48 ng L(-1), respectively. Both Hg(0) concentrations in waters (53.7 ± 18.8 pg L(-1)) and Hg(0)/THg ratios (3.8 %) in this study were significantly higher than those of the open water of the SCS in winter. Hg(0) in waters usually exhibited a clear diurnal variation with increased concentrations in daytime and decreased concentrations in nighttime, especially in cloudless days with low wind speed. Linear regression analysis suggested that Hg(0) concentrations in waters were positively and significantly correlated to the photosynthetically active radiation (PAR) (R (2) = 0.42, p < 0.001). Surface waters were always supersaturated with Hg(0) compared to air (the degree of saturation, 2.46 to 13.87), indicating that the surface water was one of the atmospheric Hg(0) sources. The air-sea Hg(0) fluxes were estimated to be 1.73 ± 1.25 ng m(-2) h(-1) with a large range between 0.01 and 6.06 ng m(-2) h(-1). The high variation of Hg(0) fluxes was mainly attributed to the greatly temporal variation of wind speed.

SU-E-T-577: Obliquity Factor and Surface Dose in Proton Beam Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, I; Andersen, A; Coutinho, L

2015-06-15

Purpose: The advantage of lower skin dose in proton beam may be diminished creating radiation related sequalae usually seen with photon and electron beams. This study evaluates the surface dose as a complex function of beam parameters but more importantly the effect of beam angle. Methods: Surface dose in proton beam depends on the beam energy, source to surface distance, the air gap between snout and surface, field size, material thickness in front of surface, atomic number of the medium, beam angle and type of nozzle (ie double scattering, (DS), uniform scanning (US) or pencil beam scanning (PBS). Obliquity factormore » (OF) is defined as ratio of surface dose in 0° to beam angle Θ. Measurements were made in water phantom at various beam angles using very small microdiamond that has shown favorable beam characteristics for high, medium and low proton energy. Depth dose measurements were performed in the central axis of the beam in each respective gantry angle. Results: It is observed that surface dose is energy dependent but more predominantly on the SOBP. It is found that as SSD increases, surface dose decreases. In general, SSD, and air gap has limited impact in clinical proton range. High energy has higher surface dose and so the beam angle. The OF rises with beam angle. Compared to OF of 1.0 at 0° beam angle, the value is 1.5, 1.6, 1,7 for small, medium and large range respectively for 60 degree angle. Conclusion: It is advised that just like range and SOBP, surface dose should be clearly understood and a method to reduce the surface dose should be employed. Obliquity factor is a critical parameter that should be accounted in proton beam therapy and a perpendicular beam should be used to reduce surface dose.« less

Evaluation of MEGAN predicted biogenic isoprene emissions at urban locations in Southeast Texas

NASA Astrophysics Data System (ADS)

Kota, Sri Harsha; Schade, Gunnar; Estes, Mark; Boyer, Doug; Ying, Qi

2015-06-01

Summertime isoprene emissions in the Houston area predicted by the Model of Emissions of Gases and Aerosol from Nature (MEGAN) version 2.1 during the 2006 TexAQS study were evaluated using a source-oriented Community Multiscale Air Quality (CMAQ) Model. Predicted daytime isoprene concentrations at nine surface sites operated by the Texas Commission of Environmental Quality (TCEQ) were significantly higher than local observations when biogenic emissions dominate the total isoprene concentrations, with mean normalized bias (MNB) ranges from 2.0 to 7.7 and mean normalized error (MNE) ranges from 2.2 to 7.7. Predicted upper air isoprene and its first generation oxidation products of methacrolein (MACR) and methyl vinyl ketone (MVK) were also significantly higher (MNB = 8.6, MNE = 9.1) than observations made onboard of NOAA's WP-3 airplane, which flew over the urban area. Over-prediction of isoprene and its oxidation products both at the surface and the upper air strongly suggests that biogenic isoprene emissions in the Houston area are significantly overestimated. Reducing the emission rates by approximately 3/4 was necessary to reduce the error between predictions and observations. Comparison of gridded leaf area index (LAI), plant functional type (PFT) and gridded isoprene emission factor (EF) used in MEGAN modeling with estimates of the same factors from a field survey north of downtown Houston showed that the isoprene over-prediction is likely caused by the combined effects of a large overestimation of the gridded EF in urban Houston and an underestimation of urban LAI. Nevertheless, predicted ozone concentrations in this region were not significantly affected by the isoprene over-predictions, while predicted isoprene SOA and total SOA concentrations can be higher by as much as 50% and 13% using the higher isoprene emission rates, respectively.

Surface dose measurements from air gaps under a bolus by using a MOSFET dosimeter in clinical oblique photon beams

NASA Astrophysics Data System (ADS)

Chung, Jin-Beom; Kim, Jae-Sung; Kim, In-Ah; Lee, Jeong-Woo

2012-10-01

This study is intended to investigate the effects of surface dose from air gaps under the bolus in clinically used oblique photon beams by using a Markus parallel-plate chamber and a metal-oxide semiconductor field-effect transistor (MOSFET) dosimeter. To evaluate the performances of the two detectors, the percentage surface doses of the MOSFET dosimeters in without an air gap under the bolus material were measured and compared with those of the Markus parallel-plate chamber. MOSFET dosimeters at the surface provided results mostly in good agreement with the parallelplate chamber. The MOSFET dosimeters seemed suitable for surface dose measurements having excellent accuracy for clinical used photon beams. The relative surface doses were measured with air gaps (2, 5, 10 mm) and without an air gap under 3 different bolus setups: (1) unbolused (no bolus), (2) 5-mm bolus, and (3) 10-mm bolus. The reductions in the surface dose substantially increased with small field size, thick bolus, and large air gap. The absolute difference in the reductions of the surface dose between the MOSFET dosimeter and the Markus parallel-plate chamber was less than 1.1%. Results at oblique angles of incidence showed larger reductions in surface dose with increasing angle of incidence. The largest reduction in surface dose was recorded for a 6 × 6 cm2 field at a 60° angle of incidence with an 10-mm air gap under a 10-mm bolus. When a 10-mm bolus was used, a reduction in the surface dose with an air gap of up to 10.5% could be achieved by varying the field size and the incident angle. Therefore, air gaps under the bolus should be avoided in radiotherapy treatment, especially for photon beam with highly oblique angles of incidence.

Air-water exchange and dry deposition of polybrominated diphenyl ethers at a coastal site in Izmir Bay, Turkey.

PubMed

Cetin, Banu; Odabasi, Mustafa

2007-02-01

The air-water exchange of polybrominated diphenyl ethers (PBDEs), an emerging class of persistent organic pollutants (POPs), was investigated using paired air-water samples (n = 15) collected in July and December, 2005 from Guzelyali Port in Izmir Bay, Turkey. Total dissolved-phase water concentrations of PBDEs (sigma7PBDEs) were 212 +/- 65 and 87 +/- 57 pg L(-1) (average +/- SD) in summer and winter, respectively. BDE-209 was the most abundant congener in all samples, followed by BDE-99 and -47. Average ambient gas-phase sigma7PBDE concentrations were between 189 +/- 61 (summer) and 76 +/- 65 pg m(-3) (winter). Net air-water exchange fluxes ranged from -0.9 +/- 1.0 (BDE-28) (volatilization) to 11.1 +/- 5.4 (BDE-209) ng m(-2) day(-1) (deposition). The BDE-28 fluxes were mainly volatilization while the other congeners were deposited. Gas- and dissolved-phase concentrations were significantly correlated (P = 0.33-0.55, p < 0.05, except for BDE-209, r = 0.05, p > 0.05) indicating thatthe atmosphere controls the surface water PBDE levels in this coastal environment. Estimated particulate dry deposition fluxes ranged between 2.7 +/- 1.9 (BDE-154) and 116 +/- 84 ng m(-2) day(-1) (BDE-209) indicating that dry deposition is also a significant input to surface waters in the study area.

Evaluation of Three Swabbing Devices for Detection of Listeria monocytogenes on Different Types of Food Contact Surfaces

PubMed Central

Lahou, Evy; Uyttendaele, Mieke

2014-01-01

Listeria monocytogenes can adhere to different types of food contact surfaces within a food processing environment. Therefore, environmental sampling devices should be capable of detecting unacceptable contamination. In this study, a sponge-stick, foam spatula and an environmental swab were evaluated on their ability to detect low concentrations of L. monocytogenes on different types of food contact surfaces. A cocktail of four L. monocytogenes serotypes was inoculated with a concentration of 100 CFU/250 cm2 onto stainless steel (SS), high density polyethylene (HDPE) and rubber surfaces in a 250 cm2 area. Immediately after inoculation and after 1 h exposure, the surfaces were swabbed with the different swabbing devices. The results of the study show only minor differences in the ability of the swabbing devices to detect L. monocytogenes. All devices were capable to detect the contamination immediately after inoculation. However, when the surfaces were allowed to air-dry for 1 h, L. monocytogenes was undetected in 11.1% of the samples (n = 27) with the sponge stick, in 7.4% of the samples (n = 27) with the foam spatula and in 3.7% of the samples (n = 27) with the environmental swab, especially on SS surfaces. The detection ability of the different devices for L. monocytogenes can be concluded to be rather high on different types of food contact surfaces. PMID:24406663

Air entrainment in hairy surfaces

NASA Astrophysics Data System (ADS)

Nasto, Alice; Regli, Marianne; Brun, P.-T.; Alvarado, José; Clanet, Christophe; Hosoi, A. E.

2016-07-01

Motivated by diving semiaquatic mammals, we investigate the mechanism of dynamic air entrainment in hairy surfaces submerged in liquid. Hairy surfaces are cast out of polydimethylsiloxane elastomer and plunged into a fluid bath at different velocities. Experimentally, we find that the amount of air entrained is greater than what is expected for smooth surfaces. Theoretically, we show that the hairy surface can be considered as a porous medium and we describe the air entrainment via a competition between the hydrostatic forcing and the viscous resistance in the pores. A phase diagram that includes data from our experiments and biological data from diving semiaquatic mammals is included to place the model system in a biological context and predict the regime for which the animal is protected by a plastron of air.

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Breathable air components. 7.506 Section 7.506... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Refuge Alternatives § 7.506 Breathable air components. (a) Breathable air shall be supplied by compressed air cylinders, compressed breathable-oxygen...

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Breathable air components. 7.506 Section 7.506... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Refuge Alternatives § 7.506 Breathable air components. (a) Breathable air shall be supplied by compressed air cylinders, compressed breathable-oxygen...

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Breathable air components. 7.506 Section 7.506... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Refuge Alternatives § 7.506 Breathable air components. (a) Breathable air shall be supplied by compressed air cylinders, compressed breathable-oxygen...

Estimation of external dose by car-borne survey in Kerala, India.

PubMed

Hosoda, Masahiro; Tokonami, Shinji; Omori, Yasutaka; Sahoo, Sarata Kumar; Akiba, Suminori; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Nair, Raghu Ram; Jayalekshmi, Padmavathy Amma; Sebastian, Paul; Iwaoka, Kazuki; Akata, Naofumi; Kudo, Hiromi

2015-01-01

A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

Nineteenth century Parisian smoke variations inferred from Eiffel Tower atmospheric electrical observations

NASA Astrophysics Data System (ADS)

Harrison, R. G.; Aplin, K. L.

Atmospheric electrical measurements provide proxy data from which historic smoke pollution levels can be determined. This approach is applied to infer autumnal Parisian smoke levels in the 1890s, based on atmospheric electric potential measurements made at the surface and the summit of the Eiffel Tower (48.7°N, 2.4°E). A theoretical model of the development of the autumn convective boundary layer is used to determine when local pollution effects dominated the Eiffel Tower potential measurements. The diurnal variation of the Eiffel Tower potential showed a single oscillation, but it differs from the standard oceanic air potential gradient (PG) variations during the period 09-17 UT, when the model indicates that the Eiffel Tower summit should be within the boundary layer. Outside these hours, the potential changes closely follow the clean air PG variation: this finding is used to calibrate the Eiffel Tower measurements. The surface smoke pollution concentration found during the morning maximum was 60±30 μg m -3, substantially lower than the values previously inferred for Kew in 1863. A vertical smoke profile was also derived using a combination of the atmospheric electrical data and boundary layer meteorology theory. Midday smoke concentration decreased with height from 60 μg m -3 at the surface to 15 μg m -3 at the top of the Eiffel Tower. The 19th century PG measurements in both polluted and clean Parisian air present a unique resource for European air pollution and atmospheric composition studies, and early evidence of the global atmospheric electrical circuit.

An Integrated Approach to Estimate Instantaneous Near-Surface Air Temperature and Sensible Heat Flux Fields during the SEMAPHORE Experiment.

NASA Astrophysics Data System (ADS)

Bourras, Denis; Eymard, Laurence; Liu, W. Timothy; Dupuis, Hélène

2002-03-01

A new technique was developed to retrieve near-surface instantaneous air temperatures and turbulent sensible heat fluxes using satellite data during the Structure des Echanges Mer-Atmosphere, Proprietes des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE) experiment, which was conducted in 1993 under mainly anticyclonic conditions. The method is based on a regional, horizontal atmospheric temperature advection model whose inputs are wind vectors, sea surface temperature fields, air temperatures around the region under study, and several constants derived from in situ measurements. The intrinsic rms error of the method is 0.7°C in terms of air temperature and 9 W m2 for the fluxes, both at 0.16° × 0.16° and 1.125° × 1.125° resolution. The retrieved air temperature and flux horizontal structures are in good agreement with fields from two operational general circulation models. The application to SEMAPHORE data involves the First European Remote Sensing Satellite (ERS-1) wind fields, Advanced Very High Resolution Radiometer (AVHRR) SST fields, and European Centre for Medium-Range Weather Forecasts (ECMWF) air temperature boundary conditions. The rms errors obtained by comparing the estimations with research vessel measurements are 0.3°C and 5 W m2.

Seasonal variation of air temperature at the Mendel Station, James Ross Island in the period of 2006-2009

NASA Astrophysics Data System (ADS)

Laska, Kamil; Prošek, Pavel; Budík, Ladislav

2010-05-01

Key words: air temperature, seasonal variation, James Ross Island, Antarctic Peninsula Recently, significant role of the atmospheric and oceanic circulation variation on positive trend of near surface air temperature along the Antarctic Peninsula has been reported by many authors. However, small number of the permanent meteorological stations located on the Peninsula coast embarrasses a detail analysis. It comprises analysis of spatiotemporal variability of climatic conditions and validation of regional atmospheric climate models. However, geographical location of the Czech Johann Gregor Mendel Station (hereafter Mendel Station) newly established on the northern ice-free part of the James Ross Island provides an opportunity to fill the gap. There are recorded important meteorological characteristics which allow to evaluate specific climatic regime of the region and their impact on the ice-shelf disintegration and glacier retreat. Mendel Station (63°48'S, 57°53'W) is located on marine terrace at the altitude of 7 m. In 2006, a monitoring network of several automatic weather stations was installed at different altitudes ranging from the seashore level up to mesas and tops of glaciers (514 m a.s.l.). In this contribution, a seasonal variation of near surface air temperature at the Mendel Station in the period of 2006-2009 is presented. Annual mean air temperature was -7.2 °C. Seasonal mean temperature ranged from +1.4 °C (December-February) to -17.7 °C (June-August). Frequently, the highest temperature occurred in the second half of January. It reached maximum of +8.1 °C. Sudden changes of atmospheric circulation pattern during winter caused a large interdiurnal variability of air temperature with the amplitude of 30 °C.

Surface-catalyzed air oxidation of hydrazines: Environmental chamber studies

NASA Technical Reports Server (NTRS)

Kilduff, Jan E.; Davis, Dennis D.; Koontz, Steven L.

1988-01-01

The surface-catalyzed air oxidation reactions of fuel hydrazines were studied in a 6500-liter fluorocarbon-film chamber at 80 to 100 ppm concentrations. First-order rate constants for the reactions catalyzed by aluminum, water-damaged aluminum (Al/Al2O3), stainless steel 304L, galvanized steel and titanium plates with surface areas of 2 to 24 sq m were determined. With 23.8 sq m of Al/Al2O3 the surface-catalyzed air oxidation of hydrazine had a half-life of 2 hours, diimide (N2H2) was observed as an intermediate and traces of ammonia were present in the final product mixture. The Al/Al2O3 catalyzed oxidation of monomethylhydrazine yielded methyldiazine (HN = NCH3) as an intermediate and traces of methanol. Unsymmetrical dimethylhydrazine gave no detectable products. The relative reactivities of hydrazine, MMH and UDMH were 130 : 7.3 : 1.0, respectively. The rate constants for Al/Al2O3-catalyzed oxidation of hydrazine and MMH were proportional to the square of the surface area of the plates. Mechanisms for the surface-catalyzed oxidation of hydrazine and diimide and the formation of ammonia are proposed.

Oxidation of volatile organic vapours in air by solid potassium permanganate.

PubMed

Mahmoodlu, Mojtaba Ghareh; Hartog, Niels; Majid Hassanizadeh, S; Raoof, Amir

2013-06-01

Volatile organic compounds (VOCs) may frequently contaminate groundwater and pose threat to human health when migrating into the unsaturated soil zone and upward to the indoor air. The kinetic of chemical oxidation has been investigated widely for dissolved VOCs in the saturated zone. But, so far there have been few studies on the use of in situ chemical oxidation (ISCO) of vapour phase contaminants. In this study, batch experiments were carried out to evaluate the oxidation of trichloroethylene (TCE), ethanol, and toluene vapours by solid potassium permanganate. Results revealed that solid potassium permanganate is able to transform the vapour of these compounds into harmless oxidation products. The degradation rates for TCE and ethanol were higher than for toluene. The degradation process was modelled using a kinetic model, linear in the gas concentration of VOC [ML(-3)] and relative surface area of potassium permanganate grains (surface area of potassium permanganate divided by gas volume) [L(-1)]. The second-order reaction rate constants for TCE, ethanol, and toluene were found to be equal to 2.0×10(-6) cm s(-1), 1.7×10(-7) cm s(-1), and 7.0×10(-8) cm s(-1), respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physical properties and application in the confined geometrical systems

NASA Astrophysics Data System (ADS)

Pak, Hunkyun

Surface viscoelasticity of a vitamin E modified polyethylene glycol (vitamin E-TPGS) monolayers at the air/water interface is deduced by the surface light scattering method and Wilhelmy plate method. It was found that the viscoelasticity of vitamin E-TPGS monolayer is similar to that of PEO monolayer at the surface pressure lower than the collapse pressure of the polyethylene oxide (PEO). However, at higher surface pressure than the collapse pressure of PEO, it deviates from the viscoelastic behavior of PEO. Lateral diffusion constants of a probe lipid (NBD-PC) in a binary monolayer of L-a-dilauroylphosphatidylcholine (DLPC) and poly-(di-isobutylene-alt-maleic acid) (PDIBMA) were determined by the fluorescence recovery after photobleaching (FRAP) method at the air/pH 7 buffer interface as a function of composition. The diffusion constant is found to retard down to less than one hundredth to that at pure DLPC monolayers as the mole fraction of PDIBMA increased. The free area model was used to interpret the probe diffusion retardation. Translational diffusion constants of a probe molecule, 4-octadecylamino-7-nitrobenzo-2-oxa-1,3-diazole (C18-NBD), in thin polyisoprene (PI) and polydimethyl siloxane (PDMS) films, spin coated on methylated and propylyaminated silicon wafers, are studied by the FRAP method as a function of film thickness. Reduction of the diffusion constant is observed as thickness of the films is decreased. Two empirical models, the two-layer model and the continuous layer model are proposed to account for the diffusion constant dependence on the film thickness vs. thickness. It was observed that the diffusion profiles in the films are dependet on the nature of the substrate surfaces. Self-assembled patterns of magnetic particles were made and fixed by applying magnetic field on the particles dispersed at the air/liquid interface, followed by gelling of the liquid subphase. With this method, the large patterns with controllable lattice constant can be made. The fixation of the subphase enhances the stability of the patterns. Further, three-dimensional self-assembled patterns can be made by this method when the fixation process is incorporated.

Inactivation of Salmonella on pecan nutmeats by hot air treatment and oil roasting.

PubMed

Beuchat, Larry R; Mann, David A

2011-09-01

Studies were done to determine the effectiveness of hot air drying, dry roasting, and oil roasting in killing Salmonella on pecan nutmeats. Pecan halves and pieces were inoculated by immersion in a five-serotype suspension of Salmonella or by surface application of powdered chalk containing the pathogen. Hot air treatment of low-moisture (2.8 to 4.1%) and high-moisture (10.5 to 11.2%) immersion-inoculated nutmeats (initial population, 6.18 to 7.16 log CFU/g) at 120°C for 20 min reduced the number of Salmonella by 1.18 to 1.26 and 1.89 to 2.04 log CFU/g, respectively. However, regardless of the moisture content, hot air treatment of pecan halves containing 0.77 log CFU/g at 120°C for 20 min failed to eliminate Salmonella. Reductions were >7 log CFU/g when dry pieces were dry roasted at 160°C for 15 min. Treatment of halves at 140°C for 20 min, 150°C for 15 min, or 170°C for 10 min reduced Salmonella by 5 log CFU/g. The pathogen was slightly more heat resistant in immersion-inoculated nutmeats than on surface-inoculated nutmeats. Exposure of immersion-inoculated pieces to peanut oil at 127°C for 1.5 min or 132°C for 1.0 min reduced the number of Salmonella by 5 log CFU/g. Treatment of halves at 138°C for 2.0 min reduced Salmonella by 5 log CFU/g; treatment at 132°C for 2.5 to 4.0 min did not always achieve this reduction. Hot air treatment cannot be relied upon to reduce Salmonella by 5 log CFU/g of raw pecan nutmeats without changing sensory qualities. Treatment temperatures and times typically used to oil roast nutmeats appear to be sufficient to reduce Salmonella by 5 log CFU/g.

Particle impactor assembly for size selective high volume air sampler

DOEpatents

Langer, Gerhard

1988-08-16

Air containing entrained particulate matter is directed through a plurality of parallel, narrow, vertically oriented impactor slots of an inlet element toward an adjacently located, relatively large, dust impaction surface preferably covered with an adhesive material. The air flow turns over the impaction surface, leaving behind the relatively larger particles according to the human thoracic separation system and passes through two elongate exhaust apertures defining the outer bounds of the impaction collection surface to pass through divergent passages which slow down and distribute the air flow, with entrained smaller particles, over a fine filter element that separates the fine particles from the air. The elongate exhaust apertures defining the impaction collection surface are spaced apart by a distance greater than the lengths of elongate impactor slots in the inlet element and are oriented to be normal thereto. By appropriate selection of dimensions and the number of impactor slots air flow through the inlet element is provided a nonuniform velocity distribution with the lower velocities being obtained near the center of the impactor slots, in order to separate out particles larger than a certain predetermined size on the impaction collection surface. The impaction collection surface, even in a moderately sized apparatus, is thus relatively large and permits the prolonged sampling of air for periods extending to four weeks.

An Air-Stripping Packed Bed Combined with a Biofilm-Type Biological Process for Treating BTEX and Total Petroleum Hydrocarbon Contaminated Groudwater

NASA Astrophysics Data System (ADS)

Hong, U.; Park, S.; Lim, J.; Lee, W.; Kwon, S.; Kim, Y.

2009-12-01

In this study, we examined the removal efficiency of a volatile compound (e.g. toluene) and a less volatile compound [e.g. total petroleum hydrocarbon (TPH)] using an air stripping packed bed combined with a biofilm-type biological process. We hypothesized that this system might be effective and economical to simultaneously remove both volatile and less volatile compounds. The gas-tight reactor has 5.9-inch-diameter and 48.8-inch-height. A spray nozzle was installed at the top cover to distribute the liquid evenly through reactor. The reactor was filled with polypropylene packing media for the increase of volatilization surface area and the growth of TPH degrading facultative aerobic bacteria on the surface of the packing media. In air stripping experiments, 45.6%, 71.7%, 72.0%, and 75.4% of toluene was removed at air injection rates of 0 L/min, 2.5 L/min, 4 L/min, and 6 L/min, respectively. Through the result, we confirmed that toluene removal efficiency increased by injecting higher amounts of air. TPH removal by stripping was minimal. To remove a less volatile TPH by commercial TPH degrading culture (BIO-ZYME B-52), 15-times diluted culture was circulated through the reactor for 2-3 days to build up a biofilm on the surface of packing media with 1 mg-soluble nitrogen source /L-water per 1 ppm of TPH. Experiments evaluating the degree of TPH biodegradation in this system are carrying out.

Uranyl adsorption and surface speciation at the imogolite-water interface: Self-consistent spectroscopic and surface complexation models

USGS Publications Warehouse

Arai, Y.; McBeath, M.; Bargar, J.R.; Joye, J.; Davis, J.A.

2006-01-01

Macro- and molecular-scale knowledge of uranyl (U(VI)) partitioning reactions with soil/sediment mineral components is important in predicting U(VI) transport processes in the vadose zone and aquifers. In this study, U(VI) reactivity and surface speciation on a poorly crystalline aluminosilicate mineral, synthetic imogolite, were investigated using batch adsorption experiments, X-ray absorption spectroscopy (XAS), and surface complexation modeling. U(VI) uptake on imogolite surfaces was greatest at pH ???7-8 (I = 0.1 M NaNO3 solution, suspension density = 0.4 g/L [U(VI)]i = 0.01-30 ??M, equilibration with air). Uranyl uptake decreased with increasing sodium nitrate concentration in the range from 0.02 to 0.5 M. XAS analyses show that two U(VI) inner-sphere (bidentate mononuclear coordination on outer-wall aluminol groups) and one outer-sphere surface species are present on the imogolite surface, and the distribution of the surface species is pH dependent. At pH 8.8, bis-carbonato inner-sphere and tris-carbonato outer-sphere surface species are present. At pH 7, bis- and non-carbonato inner-sphere surface species co-exist, and the fraction of bis-carbonato species increases slightly with increasing I (0.1-0.5 M). At pH 5.3, U(VI) non-carbonato bidentate mononuclear surface species predominate (69%). A triple layer surface complexation model was developed with surface species that are consistent with the XAS analyses and macroscopic adsorption data. The proton stoichiometry of surface reactions was determined from both the pH dependence of U(VI) adsorption data in pH regions of surface species predominance and from bond-valence calculations. The bis-carbonato species required a distribution of surface charge between the surface and ?? charge planes in order to be consistent with both the spectroscopic and macroscopic adsorption data. This research indicates that U(VI)-carbonato ternary species on poorly crystalline aluminosilicate mineral surfaces may be important in controlling U(VI) mobility in low-temperature geochemical environments over a wide pH range (???5-9), even at the partial pressure of carbon dioxide of ambient air (pCO2 = 10-3.45 atm). ?? 2006 Elsevier Inc. All rights reserved.

Youngstown MAP, Ohio. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1982-05-10

Air Weather Service ( MAC ) SCuOL2., IL 6222 R- UmmRm m "PJ M MOP Fr 4 JUN SURFACE WEATHER OSVAIWJ YOUNGSTOWN MAP OH MC #725250 N 41 16 W 080 40 ELD...percentage frequency of distribution tables OHIO YOUNGSTIOWN M "P, OHIO 20. and dew point temperatures and relative humidity); and (F) Pressure Summnary...p.ouIwuIis P i o m Qm 1 ---- .0 YN - :, 7 -AL CLIMATOLO’Y RA"CH 7 .I*.T 7C WEATHER CONDITIONS .ATH’p SEPVICE/mAC CNIIN -, JN,.S7 %N MAP OH 73-81 A U G

BRIEF COMMUNICATIONS: Experimental study of the energy balance in the interaction of a pulsed CO2 laser with metal and insulating targets in air

NASA Astrophysics Data System (ADS)

Babaeva, N. A.; Vas'kovskiĭ, Yu M.; Rovinskiĭ, R. E.; Ryabinkina, V. A.

1991-09-01

Measurements were made of components of the energy balance in the interaction of pulsed CO2 laser radiation with Dural, glass, quartz, ebonite, and Plexiglas in air at atmospheric pressure. At laser energy densities between 1 and 20 J/cm2 and in the spectral range 0.2-7 μm, the re-emission of radiation by the laser plasma was found to be less than 1 %. At energy densities exceeding 10 J/cm2, up to 90% of the laser energy failed to reach the irradiated surface.

Hot, humid air decontamination of a C-130 aircraft contaminated with spores of two acrystalliferous Bacillus thuringiensis strains, surrogates for Bacillus anthracis.

PubMed

Buhr, T L; Young, A A; Bensman, M; Minter, Z A; Kennihan, N L; Johnson, C A; Bohmke, M D; Borgers-Klonkowski, E; Osborn, E B; Avila, S D; Theys, A M G; Jackson, P J

2016-04-01

To develop test methods and evaluate survival of Bacillus thuringiensis kurstaki cry(-) HD-1 and B. thuringiensis Al Hakam spores after exposure to hot, humid air inside of a C-130 aircraft. Bacillus thuringiensis spores were either pre-inoculated on 1 × 2 or 2 × 2 cm substrates or aerosolized inside the cargo hold of a C-130 and allowed to dry. Dirty, complex surfaces (10 × 10 cm) swabbed after spore dispersal showed a deposition of 8-10 log10 m(-2) through the entire cargo hold. After hot, humid air decontamination at 75-80°C, 70-90% relative humidity for 7 days, 87 of 98 test swabs covering 0·98 m(2) , showed complete spore inactivation. There was a total of 1·67 log10 live CFU detected in 11 of the test swabs. Spore inactivation in the 98 test swabs was measured at 7·06 log10 m(-2) . Laboratory test methods for hot, humid air decontamination were scaled for a large-scale aircraft field test. The C-130 field test demonstrated that hot, humid air can be successfully used to decontaminate an aircraft. Transition of a new technology from research and development to acquisition at a Technology Readiness Level 7 is unprecedented. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Cells on Gels: Cell Behavior at the Air-Gel Interface

NASA Astrophysics Data System (ADS)

O'Bryan, Christopher; Hormel, Tristan; Bhattacharjee, Tapomoy; Sawyer, W.; Angelini, Thomas

Numerous different types of cells are often grown at air-liquid interfaces. For example, a common way to create cell spheroids is to disperse cells in a droplet of liquid media that hangs from the lid of a culture dish - the ``hanging drop'' method. Some types of epithelial cells form monolayers at the bottom of hanging drops, instead of spheroids. Corneal epithelial cells stratify and exhibit a tissue-like phenotype when attached to liquid permeable culture surfaces positioned at the air-liquid media interface (air-lifted culture). These widely used culture methods make experimentation challenging - imaging through hanging drops and air-lifted culture dishes is prohibitive. However, similar results may be achieved by culturing cells on hydrogel surfaces at the air-gel interface. In this talk we will describe a method for culturing cells at air-gel interfaces. We seed human corneal epithelial cells (hTCEpi) onto the surfaces of hydrogel networks and jammed microgels, exposed to air. Preliminary observations of cell behavior at the air-gel interface will be presented.

Effect of a surface tension gradient on the slip flow along a superhydrophobic air-water interface

NASA Astrophysics Data System (ADS)

Song, Dong; Song, Baowei; Hu, Haibao; Du, Xiaosong; Du, Peng; Choi, Chang-Hwan; Rothstein, Jonathan P.

2018-03-01

Superhydrophobic surfaces have been shown to produce significant drag reduction in both laminar and turbulent flows by introducing an apparent slip velocity along an air-water interface trapped within the surface roughness. In the experiments presented within this study, we demonstrate the existence of a surface tension gradient associated with the resultant Marangoni flow along an air-water interface that causes the slip velocity and slip length to be significantly reduced. In this study, the slip velocity along a millimeter-sized air-water interface was investigated experimentally. This large-scale air-water interface facilitated a detailed investigation of the interfacial velocity profiles as the flow rate, interfacial curvature, and interface geometry were varied. For the air-water interfaces supported above continuous grooves (concentric rings within a torsional shear flow) where no surface tension gradient exists, a slip velocity as high as 30% of the bulk velocity was observed. However, for the air-water interfaces supported above discontinuous grooves (rectangular channels in a Poiseuille flow), the presence of a surface tension gradient reduced the slip velocity and in some cases resulted in an interfacial velocity that was opposite to the main flow direction. The curvature of the air-water interface in the spanwise direction was found to dictate the details of the interfacial flow profile with reverse flow in the center of the interface for concave surfaces and along the outside of the interface for convex surfaces. The deflection of the air-water interface was also found to greatly affect the magnitude of the slip. Numerical simulations imposed with a relatively small surface tension gradient along the air-water interface were able to predict both the reduced slip velocity and back flow along the air-water interface.

Gaseous elemental mercury in the marine boundary layer and air-sea flux in the Southern Ocean in austral summer.

PubMed

Wang, Jiancheng; Xie, Zhouqing; Wang, Feiyue; Kang, Hui

2017-12-15

Gaseous elemental mercury (GEM) in the marine boundary layer (MBL), and dissolved gaseous mercury (DGM) in surface seawater of the Southern Ocean were measured in the austral summer from December 13, 2014 to February 1, 2015. GEM concentrations in the MBL ranged from 0.4 to 1.9ngm -3 (mean±standard deviation: 0.9±0.2ngm -3 ), whereas DGM concentrations in surface seawater ranged from 7.0 to 75.9pgL -1 (mean±standard deviation: 23.7±13.2pgL -1 ). The occasionally observed low GEM in the MBL suggested either the occurrence of atmospheric mercury depletion in summer, or the transport of GEM-depleted air from the Antarctic Plateau. Elevated GEM concentrations in the MBL and DGM concentrations in surface seawater were consistently observed in the ice-covered region of the Ross Sea implying the influence of the sea ice environment. Diminishing sea ice could cause more mercury evasion from the ocean to the air. Using the thin film gas exchange model, the air-sea fluxes of gaseous mercury in non-ice-covered area during the study period were estimated to range from 0.0 to 6.5ngm -2 h -1 with a mean value of 1.5±1.8ngm -2 h -1 , revealing GEM (re-)emission from the East Southern Ocean in summer. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling dynamic exchange of gaseous elemental mercury at polar sunrise.

PubMed

Dastoor, Ashu P; Davignon, Didier; Theys, Nicolas; Van Roozendael, Michel; Steffen, Alexandra; Ariya, Parisa A

2008-07-15

At polar sunrise, gaseous elemental mercury (GEM) undergoes an exceptional dynamic exchange in the air and at the snow surface during which GEM can be rapidly removed from the atmosphere (the so-called atmospheric mercury depletion events (AMDEs)) as well as re-emitted from the snow within a few hours to days in the Polar Regions. Although high concentrations of total mercury in snow following AMDEs is well documented, there is very little data available on the redox transformation processes of mercury in the snow and the fluxes of mercury at the air/snow interface. Therefore, the net gain of mercury in the Polar Regions as a result of AMDEs is still an open question. We developed a new version of the global mercury model, GRAHM, which includes for the first time bidirectional surface exchange of GEM in Polar Regions in spring and summer by developing schemes for mercury halogen oxidation, deposition, and re-emission. Also for the first time, GOME satellite data-derived boundary layer concentrations of BrO have been used in a global mercury model for representation of halogen mercury chemistry. Comparison of model simulated and measured atmospheric concentrations of GEM at Alert, Canada, for 3 years (2002-2004) shows the model's capability in simulating the rapid cycling of mercury during and after AMDEs. Brooks et al. (1) measured mercury deposition, reemission, and net surface gain fluxes of mercury at Barrow, AK, during an intensive measurement campaign for a 2 week period in spring (March 25 to April 7, 2003). They reported 1.7, 1.0 +/- 0.2, and 0.7 +/- 0.2 microg m(-2) deposition, re-emission, and net surface gain, respectively. Using the optimal configuration of the model, we estimated 1.8 microg m(-2) deposition, 1.0 microg m(-2) re-emission, and 0.8 microg m(-2) net surface gain of mercury for the same time period at Barrow. The estimated net annual accumulation of mercury within the Arctic Circle north of 66.5 degrees is approximately 174 t with +/-7 t of interannual variability for 2002-2004 using the optimal configuration. We estimated the uncertainty of the model results to the Hg/Br reaction rate coefficient to be approximately 6%. Springtime is clearly demonstrated as the most active period of mercury exchanges and net surface gain (approximately 46% of annual accumulation) in the Arctic.

GIXAFS study of Fe3+ sorption and precipitation on natural quartz surfaces

USGS Publications Warehouse

Waychunas, G.; Davis, J.; Reitmeyer, R.

1999-01-01

Grazing-incidence EXAFS has been used to characterize the structure of Fe3+ sorbed onto natural single crystal quartz surfaces. Fe3+ sorption at ca. 5% monolayer coverage on a natural crystal allowed to equilibrate in air resulted in formation of hematite nuclei with strong texturing on r-and m-planes. EXAFS calculations suggests that both O and Fe backscattering is necessary to yield acceptable structural models, that about 50% of the sorbed iron resides in nuclei, and that the approximate dimensions of the nuclei can be estimated via Feff 7.0 calculations of various nuclei sizes and shapes.

Significant OH production under surface cleaning and air cleaning conditions: Impact on indoor air quality.

PubMed

Carslaw, N; Fletcher, L; Heard, D; Ingham, T; Walker, H

2017-11-01

We report measurements of hydroxyl (OH) and hydroperoxy (HO 2 ) radicals made by laser-induced fluorescence spectroscopy in a computer classroom (i) in the absence of indoor activities (ii) during desk cleaning with a limonene-containing cleaner (iii) during operation of a commercially available "air cleaning" device. In the unmanipulated environment, the one-minute averaged OH concentration remained close to or below the limit of detection (6.5×10 5  molecule cm -3 ), whilst that of HO 2 was 1.3×10 7  molecule cm -3 . These concentrations increased to ~4×10 6 and 4×10 8  molecule cm -3 , respectively during desk cleaning. During operation of the air cleaning device, OH and HO 2 concentrations reached ~2×10 7 and ~6×10 8  molecule cm -3 respectively. The potential of these OH concentrations to initiate chemical processing is explored using a detailed chemical model for indoor air (the INDCM). The model can reproduce the measured OH and HO 2 concentrations to within 50% and often within a few % and demonstrates that the resulting secondary chemistry varies with the cleaning activity. Whilst terpene reaction products dominate the product composition following surface cleaning, those from aromatics and other VOCs are much more important during the use of the air cleaning device. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cloud Streets over the Atlantic Ocean

NASA Image and Video Library

2017-12-08

In the midst of a cold snap that sent temperatures 20–40°F (11–22°C) below normal across much of the United States, the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite captured this image of cloud streets over the Atlantic Ocean on January 7, 2014. Cloud streets—long parallel bands of cumulus clouds—form when cold air blows over warmer waters and a warmer air layer (or temperature inversion) rests over the top of both. The comparatively warm water gives up heat and moisture to the cold air above, and columns of heated air called thermals naturally rise through the atmosphere. The temperature inversion acts like a lid, so when the rising thermals hit it, they roll over and loop back on themselves, creating parallel cylinders of rotating air. As this happens, the moisture cools and condenses into flat-bottomed, fluffy-topped cumulus clouds that line up parallel to the direction of the prevailing wind. On January 7, the winds were predominantly out of the northwest. Cloud streets can stretch for hundreds of kilometers if the land or water surface underneath is uniform. Sea surface temperature need to be at least 40°F (22°C) warmer than the air for cloud streets to form. More info: earthobservatory.nasa.gov/NaturalHazards/view.php?id=82800 NASA Earth Observatory image courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC. Caption by Adam Voiland. Instrument: Terra - MODIS Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

A Subambient Open Roof Surface under the Mid-Summer Sun.

PubMed

Gentle, Angus R; Smith, Geoff B

2015-09-01

A novel material open to warm air stays below ambient temperature under maximum solar intensities of mid-summer. It is found to be 11 °C cooler than a commercial white cool roof nearby. A combination of specially chosen polymers and a silver thin film yields values near 100% for both solar reflectance, and thermal emittance at infrared wavelengths from 7.9 to 13 μm.

Multiple Ignition, Normal and Catalytic Combustion and Quenching of Fuel/Air Mixtures.

DTIC Science & Technology

1980-05-10

spray ignition results. Spray systems will be produced using a TSI vibrating orifice aerosol generator. From a small liquid reservoir under high pressure...Liebman used laser ignition of electromagnetically -15- levitated particles. An interesting contradiction presents itself in Figures 7 and 8. Because...the substrate surface has been developed and tested. When the experimental wall temperature is used as boundary condition for the gas- phase equations

Biobriefcase aerosol collector

DOEpatents

Bell, Perry M [Tracy, CA; Christian, Allen T [Madison, WI; Bailey, Christopher G [Pleasanton, CA; Willis, Ladona [Manteca, CA; Masquelier, Donald A [Tracy, CA; Nasarabadi, Shanavaz L [Livermore, CA

2009-09-22

A system for sampling air and collecting particles entrained in the air that potentially include bioagents. The system comprises providing a receiving surface, directing a liquid to the receiving surface and producing a liquid surface. Collecting samples of the air and directing the samples of air so that the samples of air with particles entrained in the air impact the liquid surface. The particles potentially including bioagents become captured in the liquid. The air with particles entrained in the air impacts the liquid surface with sufficient velocity to entrain the particles into the liquid but cause minor turbulence. The liquid surface has a surface tension and the collector samples the air and directs the air to the liquid surface so that the air with particles entrained in the air impacts the liquid surface with sufficient velocity to entrain the particles into the liquid, but cause minor turbulence on the surface resulting in insignificant evaporation of the liquid.

Aspergillus spp. prevalence in different Portuguese occupational environments: What is the real scenario in high load settings?

PubMed

Viegas, Carla; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Gomes, Anita Quintal; Viegas, Susana

2017-10-01

The genus Aspergillus is one of the most prevalent regarding fungi in several highly contaminated occupational environments. The goal of the current study was to assess the prevalence of Aspergillus spp. in different settings, focusing on those where a higher load of fungal contamination is expected according to the European Agency for Safety and Health at Work. A specific protocol to ensure a more accurate assessment of the exposure to Aspergillus spp. is proposed aimed at allowing a detailed risk characterization and management. Two wastewater treatment plants, one wastewater elevation plant, four waste treatment plants, three cork industries, five slaughter houses, four feed industries, one poultry pavilion, and two swineries, all located in the outskirts of Lisbon, were assessed. In total, 125 air samples and 125 surface samples were collected and analysed by culture-based methods. Real-time polymerase chain reaction was performed to detect fungal presence in 100 samples, targeting the Aspergillus sections Circumdati, Flavi, and Fumigati. The highest prevalence of Aspergillus spp. was found in wastewater treatment plants (69.3%; 31.1%), waste treatment plants (34.8%; 73.6%), and poultry feed industry (6.3%; 26.1%), in air and surfaces, respectively. Aspergillus spp. was also prevalent in cork industry (0.9%; 23.4%), slaughter houses (1.6%; 17.7%), and swineries (7.4%; 9.5%), in air and surfaces, respectively. The Aspergillus sections more prevalent in the air and surfaces of all the assessed settings were the Nigri section (47.46%; 44.71%, respectively), followed by Fumigati (22.28%; 27.97%, respectively) and Flavi (10.78%; 11.45%, respectively) sections. Aspergillus section Fumigati was successfully amplified by qPCR in 18 sampling sites where the presence of this fungal species had not been identified by conventional methods. It should be highlighted that the occupational exposure burden is due not only to the Aspergillus load, but also to the toxigenic potential of this genus. Based on our results, a protocol relied in the application of conventional and molecular methods in parallel is herein suggested aimed at allowing a better risk characterization and management.

Investigating Ozone Sources in California Using AJAX Airborne Measurements and Models: Implications for Stratospheric Intrusion and Long Range Transport

NASA Technical Reports Server (NTRS)

Ryoo, Ju-Mee; Johnson, Matthew S.; Iraci, Laura T.; Yates, Emma L.; Pierce, R. Bradley; Tanaka, Tomoaki; Gore, Warren

2016-01-01

High ozone concentrations at low altitudes near the surface were detected from airborne Alpha Jet Atmospheric eXperiment (AJAX) measurements on May 30, 2012. We investigate the causes of the elevated ozone concentrations using the airborne measurements and various models. GEOSchem and WRF-STILT model simulations show that the contribution from local sources is small. From MERRA reanalysis, it is found that high potential vorticity (PV) is observed at low altitudes. This high PV appears to be only partially coming through the stratospheric intrusions because the air inside the high PV region is moist, which shows that mixing appears to be enhanced in the low altitudes. Considering that diabatic heating can also produce high PV in the lower troposphere, high ozone is partially coming through stratospheric intrusion, but this cannot explain the whole ozone concentration in the target areas of the western U.S. A back-trajectory model is utilized to see where the air masses originated. The air masses of the target areas came from the lower stratosphere (LS), upper (UT), mid- (MT), and lower troposphere (LT). The relative number of trajectories coming from LS and UT is low (7.7% and 7.6%, respectively) compared to that from LT (64.1%), but the relative ozone concentration coming from LS and UT is high (38.4% and 20.95%, respectively) compared to that from LT (17.7%). The air mass coming from LT appears to be mostly coming from Asia. Q diagnostics show that there is sufficient mixing along the trajectory to indicate that ozone from the different origins is mixed and transported to the western U.S. This study shows that high ozone concentrations can be detected by airborne measurements, which can be analyzed by integrated platforms such as models, reanalysis, and satellite data.

Investigation of Ozone Sources in California Using AJAX Airborne Measurements and Models: Implications for Stratospheric Intrusion and Long Range Transport

NASA Technical Reports Server (NTRS)

Ryoo, Ju-Mee; Johnson, Matthew S.; Iraci, Laura T.; Yates, Emma L.; Pierce, R. Bradley; Tanaka, Tomoaki; Gore, Warren

2015-01-01

High ozone concentrations at low altitudes near the surface were detected from airborne Alpha Jet Atmospheric eXperiment (AJAX) measurements on May 30, 2012. We investigate the causes of the elevated ozone concentrations using the airborne measurements and various models. GEOS-chem and WRF-STILT model simulations show that the contribution from local sources is small. From MERRA reanalysis, it is found that high potential vorticity (PV) is observed at low altitudes. This high PV appears to be only partially coming through the stratospheric intrusions because the air inside the high PV region is moist, which shows that mixing appears to be enhanced in the low altitudes. Considering that diabatic heating can also produce high PV in the lower troposphere, high ozone is partially coming through stratospheric intrusion, but this cannot explain the whole ozone concentration in the target areas of the western U.S. A back-trajectory model is utilized to see where the air masses originated. The air masses of the target areas came from the lower stratosphere (LS), upper (UT), mid- (MT), and lower troposphere (LT). The relative number of trajectories coming from LS and UT is low (7.7 and 7.6, respectively) compared to that from LT (64.1), but the relative ozone concentration coming from LS and UT is high (38.4 and 20.95, respectively) compared to that from LT (17.7). The air mass coming from LT appears to be mostly coming from Asia. Q diagnostics show that there is sufficient mixing along the trajectory to indicate that ozone from the different origins is mixed and transported to the western U.S. This study shows that high ozone concentrations can be detected by airborne measurements, which can be analyzed by integrated platforms such as models, reanalysis, and satellite data.

In-Roll Stress Analysis Considering Air-Entrainment at the Roll-Inlet with the Effect of Grooves on Nip Roll Surface

NASA Astrophysics Data System (ADS)

Sasaki, Masashi; Tanimoto, Koshi; Kohno, Kazukiyo; Takahashi, Sadamu; Kometani, Hideo; Hashimoto, Hiromu

High-speed winding of paper web sometimes leads the winding system into unstable states, interlayer slippage of wound roll, paper breakage and so on, due to the excessive air-entrainment at the roll-inlet of nip contact region. These phenomena are more frequently observed on coated paper or plastic film comparing with newspaper, because the former allows little permeation of air and their surface roughness is small. Therefore, it is of vital importance to clarify the in-roll stress of wound roll considering the effect of air-entrainment. Generally, it is known that the amount of air-entrainment is affected by grooving shape of nip roll surface. In this paper, we focused on the grooving shape and investigated the relationship with the air-entrainment into two rolls being pressed each other and the grooving shape in order to achieve stable winding at high speed. We conducted experiments using small sized test machine. Entrained air-film thickness was evaluated applying the solution of the elasto-hydrodynamic lubrication for foil bearing with the consideration of nip profile at the grooved area. Air film thickness was measured to ensure the applicability of the above theory. Consequently, we found that the air film thickness can be estimated considering the effect of grooves on the nip roll surface, and that the validity of the above estimations was ensured from experimental investigations. Furthermore, it became to be able to propose the optimal shape of grooves on nip roll surface to maintain the stable winding at high speed and at large-diameter in reel.

Effects of cold front passage on turbulent fluxes over a large inland water

NASA Astrophysics Data System (ADS)

Zhang, Q.; Liu, H.

2011-12-01

Turbulent fluxes of sensible and latent heat over a large inland water in southern USA were measured using the eddy covariance method through the year of 2008. In addition, net radiation, air temperatures and relative humidity, and water temperature in different depths were also measured. The specific objective of this study is to examine effects of a cold front passage on the surface energy fluxes. For the typical cold front event selected from April 11 to 14, air temperature decreased by 16°C, while surface temperature only dropped 6°C. Atmospheric vapor pressure decreased by 1.6 kPa, while that in the water-air interface dropped 0.7 kPa. The behavior difference in the water-air interface was caused by the passage of cold, dry air masses immediately behind the cold front. During the cold front event, sensible heat and latent heat flux increased by 171 W m-2 and 284 W m-2, respectively. Linear aggression analysis showed that the sensible heat flux was proportional to the product of wind speed and the temperature gradient of water-air interface, with a correlation coefficient of 0.95. Latent heat flux was proportional to the product of wind speed and vapor pressure difference between the water surface and overlaying atmosphere, with a correlation coefficient of 0.81. Also, the correlations between both fluxes and the wind speed were weak. This result indicated that the strong wind associated with the cold front event contributed to the turbulent mixing, which indirectly enhanced surface energy exchange between the water surface and the atmosphere. The relationship between the water heat storage energy and turbulent fluxes was also examined.

From air to clothing: characterizing the accumulation of semi-volatile organic compounds to fabrics in indoor environments.

PubMed

Saini, A; Okeme, J O; Mark Parnis, J; McQueen, R H; Diamond, M L

2017-05-01

Uptake kinetics of semi-volatile organic compounds (SVOCs) present indoors, namely phthalates and halogenated flame retardants (HFRs), were characterized for cellulose-based cotton and rayon fabrics. Cotton and rayon showed similar accumulation of gas- and particle-phase SVOCs, when normalized to planar surface area. Accumulation was 3-10 times greater by rayon than cotton, when normalized to Brunauer-Emmett-Teller (BET) specific surface area which suggests that cotton could have a longer linear uptake phase than rayon. Linear uptake rates of eight consistently detected HFRs over 56 days of 0.35-0.92 m 3 /day.dm 2 planar surface area and mass transfer coefficients of 1.5-3.8 m/h were statistically similar for cotton and rayon and similar to those for uptake to passive air sampling media. These results suggest air-side controlled uptake and that, on average, 2 m 2 of clothing typically worn by a person would sequester the equivalent of the chemical content in 100 m 3 of air per day. Distribution coefficients between fabric and air (K') ranged from 6.5 to 7.7 (log K') and were within the range of partition coefficients measured for selected phthalates as reported in the literature. The distribution coefficients were similar for low molecular weight HFRs, and up to two orders of magnitude lower than the equilibrium partition coefficients estimated using the COSMO-RS model. Based on the COSMO-RS model, time to reach 95% of equilibrium for PBDEs between fabric and gas-phase compounds ranged from 0.1 to >10 years for low to high molecular weight HFRs. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Distributions and air-sea fluxes of dissolved nitrous oxide in the Yangtze River estuary and its adjacent marine area in spring and summer].

PubMed

Wang, Lan; Zhang, Gui-ling; Sun, Ming-shuang; Ren, Jing-ling

2014-12-01

Distributions and air-sea fluxes of nitrous oxide (N2O) in the seawaters of the Yangtze River estuary and its adjacent marine area were investigated during two cruises in March and July 2012. Dissolved N2O concentrations in surface waters ranged from 9.34 to 49.08 nmol x L(-1) with an average of (13.27 ± 6.40) nmol x L(-1) in spring and ranged from 7.27 to 27.81 nmol x L(-1) with an average of (10.62 ± 5.03) nmol x L(-1) in summer. There was no obvious difference between surface and bottom N2O concentrations. N2O concentrations in both surface and bottom waters decreased along the freshwater plume from the river mouth to the open sea. High values of dissolved N2O were found in turbidity maximum zone, which suggests that maximal turbidity enhances nitrification. Temperature had dual effects on dissolved N2O concentrations. N2O saturations in surface waters ranged from 86.9% to 351.3% with an average of (111.5 ± 41.4)% in spring and ranged from 111.7% to 396.0% with an average of (155.9 ± 68.4)% in summer. N2O were over-saturated at most stations. The sea-to-air fluxes of N2O were estimated to be (3.2 ± 10.9), (5.5 ± 19.3) and (12.2 ±52.3) μmol x (m2 x d)(-1) in spring and (7.3 ± 12.4), (12.7 ± 20.4) and (20.4 ± 35.9) μmol x (m2 x d)(-1) in summer using the LM86, W92 and RC01 relationships, respectively. The annual emissions of N2O from the Yangtze River estuary and its adjacent marine area were estimated to be 0.6 x 10(-2) Tg x a(-1) (LM86), 1.1 x 10(-2) Tg x a(-1) (W92) and 2.0 x 10(-2) Tg x a(-1) (RC01). Although the area of the Yangtze River estuary and its adjacent marine area only accounts for 0.02% of the total area of the world's oceans, their emission of N2O accounts for 0.06% of global oceanic N2O emission, indicating that the Yangtze River estuary and its adjacent marine area is an active area to produce and emit N2O.

Changes in air flow patterns using surfactants and thickeners during air sparging: bench-scale experiments.

PubMed

Kim, Juyoung; Kim, Heonki; Annable, Michael D

2015-01-01

Air injected into an aquifer during air sparging normally flows upward according to the pressure gradients and buoyancy, and the direction of air flow depends on the natural hydrogeologic setting. In this study, a new method for controlling air flow paths in the saturated zone during air sparging processes is presented. Two hydrodynamic parameters, viscosity and surface tension of the aqueous phase in the aquifer, were altered using appropriate water-soluble reagents distributed before initiating air sparging. Increased viscosity retarded the travel velocity of the air front during air sparging by modifying the viscosity ratio. Using a one-dimensional column packed with water-saturated sand, the velocity of air intrusion into the saturated region under a constant pressure gradient was inversely proportional to the viscosity of the aqueous solution. The air flow direction, and thus the air flux distribution was measured using gaseous flux meters placed at the sand surface during air sparging experiments using both two-, and three-dimensional physical models. Air flow was found to be influenced by the presence of an aqueous patch of high viscosity or suppressed surface tension in the aquifer. Air flow was selective through the low-surface tension (46.5 dyn/cm) region, whereas an aqueous patch of high viscosity (2.77 cP) was as an effective air flow barrier. Formation of a low-surface tension region in the target contaminated zone in the aquifer, before the air sparging process is inaugurated, may induce air flow through the target zone maximizing the contaminant removal efficiency of the injected air. In contrast, a region with high viscosity in the air sparging influence zone may minimize air flow through the region prohibiting the region from de-saturating. Copyright © 2014 Elsevier B.V. All rights reserved.

[Microbial air monitoring in operating theatre: active and passive samplings].

PubMed

Pasquarella, C; Masia, M D; Nnanga, Nga; Sansebastiano, G E; Savino, A; Signorelli, C; Veronesi, L

2004-01-01

Microbial air contamination was evaluated in 11 operating theatres using active and passive samplings. SAS (Surface Air System) air sampling was used to evaluate cfu/m3 and settle plates were used to measure the index of microbial air contamination (IMA). Samplings were performed at the same time on three different days, at three different times (before, during and after the surgical activity). Two points were monitored (patient area and perimeter of the operating theatre). Moreover, the cfu/m3 were evaluated at the air inlet of the conditioner system. 74.7% of samplings performed at the air inlet and 66.7% of the samplings performed at the patient area before the beginning of the surgical activity (at rest) exceeded the 35 cfu/m3 used as threshold value. 100% of IMA values exceeded the threshold value of 5. Using both active and passive sampling, the microbial contamination was shown to increase significantly during activity. The cfu values were higher at the patient area than at the perimeter of the operating theatre. Mean values of the cfu/m3 during activity at the patient area ranged from a minimum of 61+/-41 cfu/m3 to a maximum of 242+/-136 cfu/m3; IMA values ranged from a minimum of 19+/-10 to a maximum of 129+/-60. 15.2% of samplings performed at the patient area using SAS and 75.8% of samplings performed using settle plates exceeded the threshold values of 180 cfu/m3 and 25 respectively, with a significant difference of the percentages. The highest values were found in the operating theatre with inadequate structural and managerial conditions. These findings confirm that the microbiological quality of air may be considered a mirror of the hygienic conditions of the operating theatre. Settle plates proved to be more sensitive in detecting the increase of microbial air contamination related to conditions that could compromise the quality of the air in operating theatres.

A 7.5-Year Dataset of SSM/I-Derived Surface Turbulent Fluxes Over Global Oceans

NASA Technical Reports Server (NTRS)

Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Adizzone, Joe; Nelkin, Eric; Starr, David OC. (Technical Monitor)

2001-01-01

The global air-sea turbulent fluxes are needed for driving ocean models and validating coupled ocean-atmosphere global models. A method was developed to retrieve surface air humidity from the radiances measured by the Special Sensor Microwave/Imager (SSM/I) Using both SSM/I-retrieved surface wind and air humidity, they computed daily turbulent fluxes over global oceans with a stability-dependent bulk scheme. Based on this method, we have produced Version 1 of Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF) dataset from the SSM/I data and other data. It provides daily- and monthly-mean surface turbulent fluxes and some relevant parameters over global oceans for individual F8, F10, and F11 satellites covering the period July 1987-December 1994. It also provides 1988-94 annual- and monthly-mean climatologies of the same variables, using only F8 and F1 1 satellite data. It has a spatial resolution of 2.0 degrees x 2.5 degrees lat-long and is archived at the NASA/GSFC DAAC. The purpose of this paper is to present an updated assessment of the GSSTF 1.0 dataset.

Self-assembled diatom substrates with plasmonic functionality

NASA Astrophysics Data System (ADS)

Kwon, Sun Yong; Park, Sehyun; Nichols, William T.

2014-04-01

Marine diatoms have an exquisitely complex exoskeleton that is promising for engineered surfaces such as sensors and catalysts. For such applications, creating uniform arrays of diatom frustules across centimeter scales will be necessary. Here, we present a simple, low-cost floating interface technique to self-assemble the diatom frustules. We show that well-prepared diatoms form floating hexagonal close-packed arrays at the air-water interface that can be transferred directly to a substrate. We functionalize the assembled diatom surfaces with gold and characterize the plasmonic functionality by using surface enhanced Raman scattering (SERS). Thin gold films conform to the complex, hierarchical diatom structure and produce a SERS enhancement factor of 2 × 104. Small gold nanoparticles attached to the diatom's surface produce a higher enhancement of 7 × 104 due to stronger localization of the surface plasmons. Taken together, the large-scale assembly and plasmonic functionalization represent a promising platform to control the energy and the material flows at a complex surface for applications such as sensors and plasmonic enhanced catalysts.

Tiperon

NASA Technical Reports Server (NTRS)

Lewis, Carl E. (Inventor); Carlton, Lindley A. (Inventor); Saeks, Richard E. (Inventor)

2004-01-01

A control surface for an air vehicle (e.g., an aircraft, rocket, or missile) is useful for flight control at both subsonic and supersonic speeds. The control surface defines the outboardmost tip of a flight structure (e.g., a wing, tail or other stabilizer) of the air vehicle. Hence, the control surface is referred to as a `tiperon`. The tiperon has an approximately L-shaped configuration, and can be rotated relative to a fixed portion of the flight structure about a control axis. The respective surface areas of the tiperon sections forward and aft of the control axis are proportioned to place the subsonic center of pressure aft of the control axis to enhance aircraft control, and preferably also forward of the centroid of tiperon surface area. Also, the control surface sections forward and aft of the control axis are preferably mass-balanced, or at least nearly so, to enhance aircraft control at supersonic speeds. Either of the tiperon sections forward and aft of the control axis can be tapered to reduce the dependence of the moment exerted by air flow about the control axis, upon the tiperon's angle-of-attack. The tiperon also has enough surface area to control the air vehicle, even at low airspeeds. The invention is also directed to air vehicles incorporating one or more such control surfaces.

A 7.5-Year Dataset of SSM/I-Derived Surface Turbulent Fluxes Over Global Oceans

NASA Technical Reports Server (NTRS)

Chou, Shu-Hsien; Shie, Chung-Lin; Atlas, Robert M.; Ardizzone, Joe; Nelkin, Eric; Einaudi, Franco (Technical Monitor)

2001-01-01

The surface turbulent fluxes of momentum, latent heat, and sensible heat over global oceans are essential to weather, climate and ocean problems. Wind stress is the major forcing for driving the oceanic circulation, while Evaporation is a key component of hydrological cycle and surface heat budget. We have produced a 7.5-year (July 1987-December 1994) dataset of daily, individual monthly-mean and climatological (1988-94) monthly-mean surface turbulent fluxes over the global oceans from measurements of the Special Sensor Microwave/Imager (SSM/I) on board the US Defense Meteorological Satellite Program F8, F10, and F11 satellites. It has a spatial resolution of 2.0x2.5 latitude-longitude. Daily turbulent fluxes are derived from daily data of SSM/I surface winds and specific humidity, National Centers for Environmental Prediction (NCEP) sea surface temperatures, and European Centre for Medium-Range Weather Forecasts (ECMWF) air-sea temperature differences, using a stability-dependent bulk scheme. The retrieved instantaneous surface air humidity (with a 25-km resolution) IS found to be generally accurate as compared to the collocated radiosonde observations over global oceans. The surface wind speed and specific humidity (latent heat flux) derived from the F10 SSM/I are found to be -encrally smaller (larger) than those retrieved from the F11 SSM/I. The F11 SSM/I appears to have slightly better retrieval accuracy for surface wind speed and humidity as compared to the F10 SSM/I. This difference may be due to the orbital drift of the F10 satellite. The daily wind stresses and latent heat fluxes retrieved from F10 and F11 SSM/Is show useful accuracy as verified against the research quality in si -neasurerrients (IMET buoy, RV Moana Wave, and RV Wecoma) in the western Pacific warm pool during the TOGA COARE Intensive observing period (November 1992-February 1993). The 1988-94 seasonal-mean turbulent fluxes and input variables derived from FS and F11 SSM/Is show reasonable patterns related to seasonal variations of atmospheric general circulation. This dataset of SSM/I-derived turbulent fluxes is useful for climate studies, forcing of ocean models, and validation of coupled ocean-atmosphere global models and can be accessed through the NASA/GSFC Distributed Active Archive Center.

Convective mixing of air in firn at four polar sites

NASA Astrophysics Data System (ADS)

Kawamura, Kenji; Severinghaus, Jeffrey P.; Ishidoya, Shigeyuki; Sugawara, Satoshi; Hashida, Gen; Motoyama, Hideaki; Fujii, Yoshiyuki; Aoki, Shuji; Nakazawa, Takakiyo

2006-04-01

Air withdrawn from the firn at four polar sites (Dome Fuji, H72 and YM85, Antarctica and North GRIP, Greenland) was measured for δ15N of N 2 and δ18O of O 2 to test for the presence of convective air mixing in the top part of the firn, known as the "convective zone". Understanding the convective zone and its possible relationship to surface conditions is important for constructing accurate ice-core greenhouse gas chronologies and their phasing with respect to climate change. The thickness of the convective zone was inferred from a regression line with barometric slope of the data in the deep firn. It is less than a few meters at H72 and NGRIP, whereas a substantial convective zone is found at Dome Fuji (8.6 ± 2.6 m) and YM85 (14.0 ± 1.8 m). By matching the outputs of a diffusion model to the data, effective eddy diffusivities required to mix the firn air are found. At the surface of Dome Fuji and YM85, these are found to be several times greater than the molecular diffusivity in free air. The crossover from dominance of convection to molecular diffusion takes place at 7 ± 2, 11 ± 2 and 0.5 ± 0.5 m at Dome Fuji, YM85 and NGRIP, respectively. These depths can be used as an alternative definition of the convective zone thickness. The firn permeability at Dome Fuji is expected to be high because of intense firn metamorphism due to the low accumulation rate and large seasonal air temperature variation at the site. The firn layers in the top several meters are exposed to strong temperature gradients for several decades, leading to large firn grains and depth hoar that enhance permeability. The thick convective zone at YM85 is unexpected because the temperature, accumulation rate and near-surface density are comparable to NGRIP. The strong katabatic wind at YM85 is probably responsible for creating the deep convection. The largest convective zone found in this study is still only half of the current inconsistency implied from the deep ice core gas isotopes and firn densification models.

Limited Surface Observations Climatic Summary (LISOCS), Murmansk, USSR. Parts A-F

DTIC Science & Technology

1988-06-01

1 OPERATING LOCATION - A USAFETAC Air Weather Service (MAC) "LIMITED SURFACE OBSERVATIONS" , 3sP6FETAr CLIMATIC SUMMARY "LISOCS" MURMANSK USSR MSC ...3’ 7"󈧵 1 -𔄁 4p-5s UC S6 TLIAL PLAN (Dr ’ EES I I 0 INb N • . 1.. 9.2 7.9 .7 29.9 7.5 !NL 7 𔃾.6 3.. ’,2 17.1 66 . 2.3 3 .6 1.2 7.2 93 TC 7 . 1.3...CEIrATOLOSY R INCH PLPCENIAGE F TEE L UC -NCY Or OCCUPRC NCE (IF SUROFACE WI1ND UTPf C tION VERSUS WINE) lFEfE StEAFL T AC FRU4 POORLYOERY08AT31ON’ Alg

Characteristics of hierarchical micro/nano surface structure formation generated by picosecond laser processing in water and air

NASA Astrophysics Data System (ADS)

Rajab, Fatema H.; Whitehead, David; Liu, Zhu; Li, Lin

2017-12-01

Laser surface texturing or micro/nano surface structuring in the air has been extensively studied. However, until now, there are very few studies on the characteristics of laser-textured surfaces in water, and there was no reported work on picosecond laser surface micro/nano-structuring in water. In this work, the surface properties of picosecond laser surface texturing in water and air were analysed and compared. 316L stainless steel substrates were textured using a picosecond laser. The surface morphology and the chemical composition were characterised using Philips XL30 FEG-SEM, EDX and confocal laser microscopy. The wettability of the textured surfaces was determined using a contact angle analyser FTA 188. Results showed that a variety of hierarchical micro/nano surface patterns could be controlled by a suitable adjustment of laser parameters. Not only surface morphology but also remarkable differences in wettability, optical reflectivity and surface oxygen content were observed for different types of surface textures produced by laser surface texture in water and air. The possible mechanisms of the changes in the behaviour of laser-textured surfaces are discussed.

Improved Surface and Tropospheric Temperatures Determined Using Only Shortwave Channels: The AIRS Science Team Version-6 Retrieval Algorithm

NASA Technical Reports Server (NTRS)

Susskind, Joel; Blaisdell, John; Iredell, Lena

2011-01-01

The Goddard DISC has generated products derived from AIRS/AMSU-A observations, starting from September 2002 when the AIRS instrument became stable, using the AIRS Science Team Version-5 retrieval algorithm. The AIRS Science Team Version-6 retrieval algorithm will be finalized in September 2011. This paper describes some of the significant improvements contained in the Version-6 retrieval algorithm, compared to that used in Version-5, with an emphasis on the improvement of atmospheric temperature profiles, ocean and land surface skin temperatures, and ocean and land surface spectral emissivities. AIRS contains 2378 spectral channels covering portions of the spectral region 650 cm(sup -1) (15.38 micrometers) - 2665 cm(sup -1) (3.752 micrometers). These spectral regions contain significant absorption features from two CO2 absorption bands, the 15 micrometers (longwave) CO2 band, and the 4.3 micrometers (shortwave) CO2 absorption band. There are also two atmospheric window regions, the 12 micrometer - 8 micrometer (longwave) window, and the 4.17 micrometer - 3.75 micrometer (shortwave) window. Historically, determination of surface and atmospheric temperatures from satellite observations was performed using primarily observations in the longwave window and CO2 absorption regions. According to cloud clearing theory, more accurate soundings of both surface skin and atmospheric temperatures can be obtained under partial cloud cover conditions if one uses observations in longwave channels to determine coefficients which generate cloud cleared radiances R(sup ^)(sub i) for all channels, and uses R(sup ^)(sub i) only from shortwave channels in the determination of surface and atmospheric temperatures. This procedure is now being used in the AIRS Version-6 Retrieval Algorithm. Results are presented for both daytime and nighttime conditions showing improved Version-6 surface and atmospheric soundings under partial cloud cover.

KSC-97pc679

NASA Image and Video Library

1997-04-21

Workers prepare to tow away the large container with the Cassini orbiter from KSC’s Shuttle Landing Facility. The orbiter just arrived on the U.S. Air Force C-17 air cargo plane, shown here, from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn’s largest moon, Titan. The orbiter was designed and assembled at NASA’s Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004

KSC-97pc677

NASA Image and Video Library

1997-04-21

Workers begin unloading the Cassini orbiter from a U.S. Air Force C-17 air cargo plane after its arrival at KSC’s Shuttle Landing Facility from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn’s largest moon, Titan. The orbiter was designed and assembled at NASA’s Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004

Observed Reduction In Surface Solar Radiation - Aerosol Forcing Versus Cloud Feedback?

NASA Astrophysics Data System (ADS)

Liepert, B.

The solar radiation reaching the ground is a key parameter for the climate system. It drives the hydrological cycle and numerous biological processes. Surface solar radi- ation revealed an estimated 7W/m2 or 4% decline at sites worldwide from 1961 to 1990. The strongest decline occurred at the United States sites with 19W/m2 or 10%. Increasing air pollution and hence direct and indirect aerosol effect, as we know today can only explain part of the reduction in solar radiation. Increasing cloud optical thick- ness - possibly due to global warming - is a more likely explanation for the observed reduction in solar radiation in the United States. The analysis of surface solar radiation data will be shown and compared with GCM results of the direct and indirect aerosol effect. It will be argued that the residual declines in surface solar radiation is likely due to cloud feedback.

Comparison of coseismic near-field and off-fault surface deformation patterns of the 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine earthquakes: Implications for controls on the distribution of surface strain

NASA Astrophysics Data System (ADS)

Milliner, C. W. D.; Dolan, J. F.; Hollingsworth, J.; Leprince, S.; Ayoub, F.

2016-10-01

Subpixel correlation of preevent and postevent air photos reveal the complete near-field, horizontal surface deformation patterns of the 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine ruptures. Total surface displacement values for both earthquakes are systematically larger than "on-fault" displacements from geologic field surveys, indicating significant distributed, inelastic deformation occurred along these ruptures. Comparison of these two data sets shows that 46 ± 10% and 39 ± 22% of the total surface deformation were distributed over fault zones averaging 154 m and 121 m in width for the Landers and Hector Mine events, respectively. Spatial variations of distributed deformation along both ruptures show correlations with the type of near-surface lithology and degree of fault complexity; larger amounts of distributed shear occur where the rupture propagated through loose unconsolidated sediments and areas of more complex fault structure. These results have basic implications for geologic-geodetic rate comparisons and probabilistic seismic hazard analysis.

Vertical ozone characteristics in urban boundary layer in Beijing.

PubMed

Ma, Zhiqiang; Xu, Honghui; Meng, Wei; Zhang, Xiaoling; Xu, Jing; Liu, Quan; Wang, Yuesi

2013-07-01

Vertical ozone and meteorological parameters were measured by tethered balloon in the boundary layer in the summer of 2009 in Beijing, China. A total of 77 tethersonde soundings were taken during the 27-day campaign. The surface ozone concentrations measured by ozonesondes and TEI 49C showed good agreement, albeit with temporal difference between the two instruments. Two case studies of nocturnal secondary ozone maxima are discussed in detail. The development of the low-level jet played a critical role leading to the observed ozone peak concentrations in nocturnal boundary layer (NBL). The maximum of surface ozone was 161.7 ppbv during the campaign, which could be attributed to abundant precursors storage near surface layer at nighttime. Vertical distribution of ozone was also measured utilizing conventional continuous analyzers on 325-m meteorological observation tower. The results showed the NBL height was between 47 and 280 m, which were consistent with the balloon data. Southerly air flow could bring ozone-rich air to Beijing, and the ozone concentrations exceeded the China's hourly ozone standard (approximately 100 ppb) above 600 m for more than 12 h.

Theoretical Models for Evaluation of Volatile Emissions to Air During Dredged Material Disposal with Applications to New Bedford Harbor, Massachusetts

DTIC Science & Technology

1989-05-01

model otherwise. 7. One or more partial differential equations can be presented to describe the minutia of chemical behavior in the various locales of...enjoys a voluminous literature heritage beyond the point of realistic applications to the natural environment in many cases. Hill, Myers, and Brannon...represented by the point A in Figure 2. This point may be representative of the recently deposited and exposed surface of dredged sediment in the delta

Static Air Support Surfaces to Prevent Pressure Injuries: A Multicenter Cohort Study in Belgian Nursing Homes.

PubMed

Serraes, Brecht; Beeckman, Dimitri

2016-01-01

The aim of this study was to investigate the incidence and risk factors for developing pressure injuries (PIs) in patients placed on a static air support surfaces: mattress overlay, heel wedge, and seat cushion. Multicenter cohort study. The sample comprised 176 residents; their mean age was 87 (SD = 6.76) years; their mean Braden Scale score was 14 (SD = 2.54). The study was performed on a convenience sample of 6 nursing homes in Belgium. Data were collected on 23 care units. The primary outcome measure, cumulative PI incidence (category [stage] II-IV) over a 30-day observation period, was calculated. Pressure injury occurrence was defined according to the 2014 European and US National Pressure Injury Advisory panels, Pan Pacific Pressure Injury Alliance classification system. The PI incidence for category (stage) II-IV was 5.1%. Six residents (3.4%) developed a category II PI, and 3 (1.7%) developed a category III PI; no category IV ulcers occurred. No significant risk factors for category II-IV PIs were identified using multivariate logistic regression. Time of sitting in a chair was found to be a risk factor for development of nonblanchable erythema (category I PI) (odds ratio = 21.608; 95% confidence interval [CI], 20.510-22.812; P = .013). The median time to develop a category II-IV PI was 16 days (interquartile range = 2-26). The interrater reliability between the observations of the researcher and nurses on-site was almost perfect (0.86; 95% CI, 0.81-0.91). We found a low incidence of PIs when using a static air overlay mattress for patients at risk in a nursing home population. Static air support surfaces, alongside patient-tailored patient repositioning protocols, should be considered to prevent PIs in this patient population.

Earth Observation

NASA Image and Video Library

2013-06-24

ISS036-E-011843 (24 June 2013) --- Gravity waves and sunglint on Lake Superior are featured in this image photographed by an Expedition 36 crew member on the International Space Station. From the vantage point of the space station, crew members frequently observe Earth atmospheric and surface phenomena in ways impossible to view from the ground. Two such phenomena?gravity waves and sunglint?are illustrated in this photograph of northeastern Lake Superior. The Canadian Shield of southern Ontario (bottom) is covered with extensive green forest canopy typical of early summer. Offshore, and to the west and southwest of Pukaskwa National Park several distinct sets of parallel cloud bands are visible. Gravity waves are produced when moisture-laden air encounters imbalances in air density, such as might be expected when cool air flows over warmer air; this can cause the flowing air to oscillate up and down as it moves, causing clouds to condense as the air rises (cools) and evaporate away as the air sinks (warms). This produces parallel bands of clouds oriented perpendicular to the wind direction. The orientation of the cloud bands visible in this image, parallel to the coastlines, suggests that air flowing off of the land surfaces to the north is interacting with moist, stable air over the lake surface, creating gravity waves. The second phenomenon?sunglint?effects the water surface around and to the northeast of Isle Royale (upper right). Sunglint is caused by light reflection off a water surface; some of the reflected light travels directly back towards the observer, resulting in a bright mirror-like appearance over large expanses of water. Water currents and changes in surface tension (typically caused by presence of oils or surfactants) alter the reflective properties of the water, and can be highlighted by sunglint. For example, surface water currents are visible to the east of Isle Royale that are oriented similarly to the gravity waves ? suggesting that they too are the product of winds moving off of the land surface.

SU-F-T-424: Mitigation of Increased Surface Dose When Treating Through A Carbon Fiber Couch Top

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, E; Misgina, F

Purpose: To study the effect of the Varian carbon fiber couch top on surface dose for patients being treated using single PA beams in the supine position and to identify simple methods for surface dose reduction. Methods: Measurements of surface dose were obtained in Solid Water phantoms using both a parallel plate ionization chamber (PTW Advanced Markus) and EBT2 Radiochromic films for both 6 and 10MV photons. All measurements were referenced to a depth considered a typical for PA Spine fields. Techniques used to reduce the surface dose included introducing an air standoff using Styrofoam sheets to suspend the phantommore » surface above the couch top and by adding a thin high Z scattering foil on the table surface. Surface doses were evaluated for typical field sizes, standoff heights, and various scattering materials. Comparisons were made to the surface dose obtainable when treating through a Varian Mylar covered tennis racket style couch top. Results: Dependence on typical spine field sizes was relatively minor. Dependence on air gap was much more significant. Surface doses decreased exponentially with increases in air standoff distance. Surface doses were reduced by approximately 50% for an air gap of 10cm and 40% for a 15cm air gap. Surface doses were reduced by an additional 15% by the addition of a 1mm Tin scattering foil. Conclusion: Using simple techniques, it is possible to reduce the surface dose when treating single PA fields through the Varian carbon fiber couch top. Surface doses can be reduced to levels observed when treating though transparent Mylar tops by adding about 15 cm of air gap. Further reductions are possible by adding thin scattering foils, such as Tin or Lead, on the couch surface. This is a low cost approach to reduce surface dose when using the Varian carbon fiber couch top.« less

Surface temperature and thermal penetration depth of Nd:YAG laser applied to enamel and dentin

NASA Astrophysics Data System (ADS)

White, Joel M.; Neev, Joseph; Goodis, Harold E.; Berns, Michael W.

1992-06-01

The determination of the thermal effects of Nd:YAG laser energy on enamel and dentin is critical in understanding the clinical applications of caries removal and surface modification. Recently extracted non-carious third molars were sterilized with gamma irradiation. Calculus and cementum were removed using scaling instruments and 600 grit sand paper. The smear layer produced by sanding was removed with a solution of 0.5 M EDTA (pH 7.4) for two minutes. Enamel and dentin surfaces were exposed to a pulsed Nd:YAG laser with 150 microsecond(s) pulse duration. Laser energy was delivered to the teeth with a 320 micrometers diameter fiberoptic delivery system, for exposure times of 1, 10 and 30 seconds. Laser parameters varied from 0.3 to 3.0 W, 10 to 30 Hz and 30 to 150 mJ/pulse. Other conditions included applications of hot coffee, carbide bur in a dental air-cooled turbine drill and soldering iron. Infrared thermography was used to measure the maximum surface temperature on, and thermal penetration distance into enamel and dentin. Thermographic data were analyzed with a video image processor to determine the diameter of maximum surface temperature and thermal penetration distance of each treatment. Between/within statistical analysis of variance (p

Associations between PBDEs in Office Air, Dust, and Surface Wipes

PubMed Central

Watkins, Deborah J.; McClean, Michael D.; Fraser, Alicia J.; Weinberg, Janice; Stapleton, Heather M.; Webster, Thomas F.

2013-01-01

Increased use of flame-retardants in office furniture may increase exposure to PBDEs in the office environment. However, partitioning of PBDEs within the office environment is not well understood. Our objectives were to examine relationships between concurrent measures of PBDEs in office air, floor dust, and surface wipes. We collected air, dust, and surface wipe samples from 31 offices in Boston, MA. Correlation and linear regression were used to evaluate associations between variables. Geometric mean (GM) concentrations of individual BDE congeners in air and congener specific octanol-air partition coefficients (Koa) were used to predict GM concentrations in dust and surface wipes and compared to the measured concentrations. GM concentrations of PentaBDEs in office air, dust, and surface wipes were 472 pg/m3, 2411 ng/g, and 77 pg/cm2, respectively. BDE209 was detected in 100% of dust samples (GM=4202 ng/g), 93% of surface wipes (GM=125 pg/cm2), and 39% of air samples. PentaBDEs in dust and air were moderately correlated with each other (r=0.60, p=0.0003), as well as with PentaBDEs in surface wipes (r=0.51, p=0.003 for both dust and air). BDE209 in dust was correlated with BDE209 in surface wipes (r=0.69, p=0.007). Building (three categories) and PentaBDEs in dust were independent predictors of PentaBDEs in both air and surface wipes, together explaining 50% (p=0.0009) and 48% (p=0.001) of the variation respectively. Predicted and measured concentrations of individual BDE congeners were highly correlated in dust (r=0.98, p<0.0001) and surface wipes (r=0.94, p=002). BDE209 provided an interesting test of this equilibrium partitioning model as it is a low volatility compound. Associations between PentaBDEs in multiple sampling media suggest that collecting dust or surface wipes may be a convenient method of characterizing exposure in the indoor environment. The volatility of individual congeners, as well as physical characteristics of the indoor environment, influence relationships between PBDEs in air, dust, and surface wipes. PMID:23797055

Enrichment of Extracellular Carbonic Anhydrase in the Sea Surface Microlayer and Its Effect on Air-Sea CO2 Exchange

NASA Astrophysics Data System (ADS)

Mustaffa, N. I. H.; Striebel, M.; Wurl, O.

2017-12-01

This paper describes the quantification of extracellular carbonic anhydrase (eCA) concentrations in the sea surface microlayer (SML), the boundary layer between the ocean and the atmosphere of the Indo-West Pacific. We demonstrated that the SML is enriched with eCA by 1.5 ± 0.7 compared to the mixed underlying water. Enrichment remains up to a wind speed of 7 m s-1 (i.e., under typical oceanic conditions). As eCA catalyzes the interconversion of HCO3- and CO2, it has been hypothesized that its enrichment in the SML enhances the air-sea CO2 exchange. We detected concentrations in the range of 0.12 to 0.76 nM, which can enhance the exchange by up to 15% based on the model approach described in the literature.

Fabrication of Schottky Junction Between Au and SrTiO3

NASA Astrophysics Data System (ADS)

Inoue, Akira; Izumisawa, Kei; Uwe, Hiromoto

2001-05-01

A Schottky junction with a high rectification ratio between Au and La-doped SrTiO3 has been fabricated using a simple surface treatment. Highly La-doped (5%) SrTiO3 single crystals are annealed in O2 atmosphere at about 1000°C for 1 h and etched in HNO3 for more than five min. The HNO3 etching is performed in a globe box containing N2 to prevent pollution from the air. After the treatment, Au is deposited on the SrTiO3 surface in a vacuum (˜ 10-7 Torr) with an e-gun evaporator. The current voltage characteristics of the junction have shown excellent rectification properties, although junctions using neither annealed nor etched SrTiO3 exhibit high leak current in reverse voltage. The rectification ratio of the junction at 1 V is more than six orders of magnitude and there is no hysteresis in the current voltage spectra. The logarithm of the current is linear with the forward bias voltage. The ideal factor of the junction is estimated to be about 1.68. These results suggest that, if prevented from being pollution by the air, a good Schottky junction can be obtained by easy processes such as annealing in oxygen atmosphere and surface etching with acid.

Tooth Surface Comparison after Air Polishing and Rubber Cup: A Scanning Electron Microscopy Study.

PubMed

Camboni, Sara; Donnet, Marcel

2016-03-01

To demonstrate, using microscopic observations, the difference between two well-known oral prophylaxis techniques: polishing paste and air polishing. The observations were performed on human enamel. Enamel samples were obtained from plaque-rich human teeth extracted for orthodontic or clinical purposes. In order to allow a reliable comparison between different applications, each enamel sample was divided into two parts: one underwent air-polishing, whereas polishing paste was applied to the other. AIR-FLOW® Master was selected together with AIR-FLOW® PLUS for the prophylaxis powder application. For the polishing-paste application, several different pastes where used, including Cleanic®, CCS®, Proxyt®, and SuperPolish. A comparative test control was also used by cleaning the enamel with sodium hypochlorite (6%). The enamel treated with AIR-FLOW PLUS showed a similar surface when compared to the control enamel; however, there was complete cleaning down to the tooth microstructure. On the other hand, use of the polishing paste resulted in an enamel surface that appeared abraded and flattened. Moreover, some of the natural irregular enamel surfaces demonstrated some filling in with debris. AIR-FLOW PLUS powder was able to more deeply clean without creating any damage to the enamel, making it suitable for regular cleaning treatments. The polishing pastes were found to abrade the enamel surface, to flatten it, and deposit debris into the microcavities. Both methods having different mechanical effects can therefore be considered as complementary, in that some patients experience a sense of "roughness" following a cleaning. A clinical recommendation for this experience would be to use the air polish first to clean the enamel surface, and follow with a little polishing paste to smooth the surface, if required.

Improved particle impactor assembly for size selective high volume air sampler

DOEpatents

Langer, G.

1987-03-23

Air containing entrained particulate matter is directed through a plurality of parallel, narrow, vertically oriented apertures of an inlet element toward an adjacently located, relatively large, dust impaction surface preferably covered with an adhesive material. The air flow turns over the impaction surface, leaving behind, the relatively larger particles and passes through two elongate apertures defining the outer bounds of the impaction collection surface to pass through divergent passages which slow down and distribute the air flow, with entrained smaller particles, over a fine filter element that separates the fine particles from the air. By appropriate selection of dimensions and the number of inlet apertures air flow through the inlet element is provided a nonuniform velocity distribution with the lower velocities being obtained near the center of the inlet apertures, to separate out particles larger than a certain predetermined size on the impaction collection surface. The impaction collection surface, even in a moderately sized apparatus, is thus relatively large and permits the prolonged sampling of air for periods extending to four weeks. 6 figs.

Carbon speciation at the air-sea interface during rain

NASA Astrophysics Data System (ADS)

McGillis, Wade; Hsueh, Diana; Takeshita, Yui; Donham, Emily; Markowitz, Michele; Turk, Daniela; Martz, Todd; Price, Nicole; Langdon, Chris; Najjar, Raymond; Herrmann, Maria; Sutton, Adrienne; Loose, Brice; Paine, Julia; Zappa, Christopher

2015-04-01

This investigation demonstrates the surface ocean dilution during rain events on the ocean and quantifies the lowering of surface pCO2 affecting the air-sea exchange of carbon dioxide. Surface salinity was measured during rain events in Puerto Rico, the Florida Keys, East Coast USA, Panama, and the Palmyra Atoll. End-member analysis is used to determine the subsequent surface ocean carbonate speciation. Surface ocean carbonate chemistry was measured during rain events to verify any approximations made. The physical processes during rain (cold, fresh water intrusion and buoyancy, surface waves and shear, microscale mixing) are described. The role of rain on surface mixing, biogeochemistry, and air-sea gas exchange will be discussed.

Monte Carlo modeling of the MammoSite(Reg) treatments: Dose effects of air pockets

NASA Astrophysics Data System (ADS)

Huang, Yu-Huei Jessica

In the treatment of early-stage breast cancer, MammoSiteRTM has been used as one of the partial breast irradiation techniques after breast-conserving surgery. The MammoSiteRTM applicator is a single catheter with an inflatable balloon at its distal end that can be placed in the resected cavity (tumor bed). The treatment is performed by delivering the Ir-192 high-dose-rate source through the center lumen of the catheter by a remote afterloader while the balloon is inflated in the tumor bed cavity. In the MammoSiteRTM treatment, it has been found that air pockets occasionally exist and can be seen and measured in CT images. Experiences have shown that about 90% of the patients have air pockets when imaged two days after the balloon placement. The criterion for the air pocket volume is less than or equal to 10% of the planning target volume in volume. The purpose of this study is to quantify dose errors occurring at the interface of the air pocket in MammoSiteRTM treatments with Monte Carlo calculations, so that the dosimetric effects from the air pocket can be fully understood. Modern brachytherapy treatment planning systems typically consider patient anatomy as a homogeneous water medium, and incorrectly model lateral and backscatter radiation during treatment delivery. Heterogeneities complicate the problem and may result in overdosage to the tissue located near the medium interface. This becomes a problem in MammoSiteRTM brachytherapy when air pocket appears during the treatment. The resulting percentage dose difference near the air-tissue interface is hypothesized to be greater than 10% when comparing Monte Carlo N-Particle (version 5) with current treatment planning systems. The specific aims for this study are: (1) Validate Monte Carlo N-Particle (Version 5) source modeling. (2) Develop phantom. (3) Calculate phantom doses with Monte Carlo N-Particle (Version 5) and investigate doses difference between thermoluminescent dosimeter measurement, treatment planning system, and Monte Carlo results. (4) Calculate dose differences for various treatment parameters. The results from thermoliminescent dosimeter phantom measurements proves that with correct geometric and source models, Monte Carlo method can be used to estimate homogeneity and heterogeneity doses in MammoSiteRTM treatment. The resulting dose differences at various points of interests in Monte Carlo calculations were presented and compared between different calculation methods. The air pocket doses were found to be underestimated by the treatment planning system. It was concluded that after correcting for inverse square law, the underestimation error from the treatment planning system will be less than +/- 2.0%, and +/- 3.5%, at the air pocket surface and air pocket planning target volume, respectively, when comparing Monte Carlo N-Particle (version 5) results. If the skin surface is located close to the air pocket, the underestimation effect at the air pocket surface and air pocket planning target volume doses becomes less because the air outside of the skin surface reduces the air pocket inhomogeneity effect. In order to maintain appropriate skin dose within tolerance, the skin surface criterion should be considered as the smallest thickness of the breast tissue located between the air pocket and the skin surface. The thickness should be at least 5 mm. In conclusion, the air pocket outside the balloon had less than 10% inhomogeneity effect based on the situations studied. It is recommended that at least an inverse square correction should be taken into consideration in order to relate clinical outcomes to actual delivered doses to the air pocket and surrounding tissues.

Evaluation of Day and Nighttime Lower Tropospheric Ozone from Air Quality Models using TES and Ozonesondes

NASA Astrophysics Data System (ADS)

Osterman, G. B.; Neu, J. L.; Eldering, A.; Pinder, R. W.; Tang, Y.; McQueen, J.

2012-12-01

At night, ozone can be transported long distances above the surface inversion layer without chemical destruction or deposition. As the boundary layer breaks up in the morning, this nocturnal ozone can be mixed down to the surface and rapidly increase ozone concentrations at a rate that can rival chemical ozone production. Most regional scale models that are used for air quality forecasts and ozone source attribution do not adequately capture nighttime ozone concentrations and transport. We combine ozone profile data from the NASA Earth Observing System (EOS) Tropospheric Emission Spectrometer (TES) and other sensors, ozonesonde data collected during the INTEX Ozonesonde Network Study (IONS), EPA AirNow ground station ozone data, the Community Multi-Scale Air Quality (CMAQ) model, and the National Air Quality Forecast Capability (NAQFC) model to examine air quality events during August 2006. We present both aggregated statistics and case-study analyses that assess the relationship between the models' ability to reproduce surface air quality events and their ability to capture the vertical distribution of ozone both during the day and at night. We perform the comparisons looking at the geospatial dependence in the differences between the measurements and models under different surface ozone conditions.

Global Distribution and Variability of Surface Skin and Surface Air Temperatures as Depicted in the AIRS Version-6 Data Set

NASA Technical Reports Server (NTRS)

Susskind, Joel; Lee, Jae N.; Iredell, Lena

2014-01-01

In this presentation, we will briefly describe the significant improvements made in the AIRS Version-6 retrieval algorithm, especially as to how they affect retrieved surface skin and surface air temperatures. The global distribution of seasonal 1:30 AM and 1:30 PM local time 12 year climatologies of Ts,a will be presented for the first time. We will also present the spatial distribution of short term 12 year anomaly trends of Ts,a at 1:30 AM and 1:30 PM, as well as the spatial distribution of temporal correlations of Ts,a with the El Nino Index. It will be shown that there are significant differences between the behavior of 1:30 AM and 1:30 PM Ts,a anomalies in some arid land areas.

On the Current Trend of Tropical Cyclone Activity and the Lengthening of the Tropical Cyclone Season in the North Atlantic Basin

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2013-01-01

In this TP, the trend in North Atlantic basin TC activity, especially as related to the determination of the length of season (LOS) and its possible association with warming surface-air and sea-surface temperature, is revisited. In particular, examined are: (1) the trend in TC activity for the yearly intervals 1945-1965, 1966-1994, and 1995-2012 for TCs having duration NSD greater or equal to 0.25 day, less than 2 days, greater than or equal to 2 days, greater than or equal to 4 days, and greater than or equal to 8 days; (2) the latitudinal and longitudinal genesis locations of the short-lived TC (defined herein as those TCs having duration NSD less than 2 days) for the three yearly intervals; (3) the first storm day (FSD), last storm day (LSD), and LOS based on TCs having duration NSD greater than or equal to 0.25 day and NSD greater than or equal to 2 days; (4) the relationship between FSD, LSD, and LOS for TCs having duration NSD greater than or equal to 0.25 day and NSD greater than or equal to 2 days; (5) the surface-air and sea-surface temperature, wind, and North Atlantic Oscillation (NAO) during the interval 1945-2012; (6) the relationship of FSD, LSD, and LOS against surface-air and sea-surface temperature, wind, and the NAO; (7) the relationship of TC activity against surface-air and sea-surface temperature, wind, and the NAO; and (8) the relationship of TC activity against FSD and LOS. This TP represents an update to an earlier study by Wilson concerning the length of the yearly hurricane season.

National emission standards for hazardous air pollutants for shipbuilding and ship repair facilities (surface coating). Background information for final standards. Volume 2. Summary of public comments and responses

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-08-01

National emission standards for control of HAP emissions from surface coating operations at shipbuilding and ship repair facilities was promulgated under the authority of Section 112 of the Clean Air Act. The Standards will reduce air toxics from all major source shipyards (defined as those shipyards that emit 9.1 Mg/yr (10 tons/yr) or greater of any HAP material or 22.7 Mg/yr (25 tons/yr) or greater of any combination of HAP materials). This document provides: (1) the basis for the revisions made to the standards between proposal and promulgation; (2) a summary of the comments submitted and the responses to thesemore » comments; and (3) a summary of the changes made since proposal.« less

Normal- and oblique-shock flow parameters in equilibrium air including attached-shock solutions for surfaces at angles of attack, sweep, and dihedral

NASA Technical Reports Server (NTRS)

Hunt, J. L.; Souders, S. W.

1975-01-01

Normal- and oblique-shock flow parameters for air in thermochemical equilibrium are tabulated as a function of shock angle for altitudes ranging from 15.24 km to 91.44 km in increments of 7.62 km at selected hypersonic speeds. Post-shock parameters tabulated include flow-deflection angle, velocity, Mach number, compressibility factor, isentropic exponent, viscosity, Reynolds number, entropy difference, and static pressure, temperature, density, and enthalpy ratios across the shock. A procedure is presented for obtaining oblique-shock flow properties in equilibrium air on surfaces at various angles of attack, sweep, and dihedral by use of the two-dimensional tabulations. Plots of the flow parameters against flow-deflection angle are presented at altitudes of 30.48, 60.96, and 91.44 km for various stream velocities.

DISCOVER-AQ: An Overview and Initial Comparisons of NO2 with OMI Observations

NASA Technical Reports Server (NTRS)

Pickering, Kenneth; Crawford, James; Krotkov, Nickolay; Bucsela, Eric; Lamsal, Lok; Celarier, Edward; Herman, Jay; Janz, Scott; Cohen, Ron; Weinheimer, Andrew

2011-01-01

The first deployment of the Earth Venture -1 DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project was conducted during July 2011 in the Baltimore-Washington region. Two aircraft (a P-3B for in-situ sampling and a King Air for remote sensing) were used along with an extensive array of surface-based in-situ and remote sensing instrumentation. Fourteen flight days were accomplished by both aircraft and over 250 profiles of trace gases and aerosols were performed by the P-3B over surface air quality monitoring stations, which were specially outfitted with sunphotometers and Pandora UV/Vis spectrometers. The King Air flew with the High Spectral Resolution Lidar for aerosols and the ACAM UV/Vis spectrometer for trace gases. This suite of observations allows linkage of surface air quality with the vertical distributions of gases and aerosols, with remotely-sensed column amounts observed from the surface and from the King Air, and with satellite observations from Aura (OMI and TES), GOME-2, MODIS and GOES. The DISCOVER-AQ data will allow determination of under what conditions satellite retrievals are indicative of surface air quality, and they will be useful in planning new satellites. In addition to an overview of the project, a preliminary comparison of tropospheric column NO2 densities from the integration of in-situ P-3B observations, from the Pandoras and ACAM, and from the new Goddard OMI NO2 algorithm will be presented.

Air Force Air Refueling: The KC-X Aircraft Acquisition Program

DTIC Science & Technology

2008-08-04

7 Boom vs . Probe and Drogue Air Refueling . . . . . . . . . . . . . . . . . . . . . . 7 Capacity vs ...consideration must be given to a few key attributes. For example, a tanker aircraft’s method of dispensing fuel – flying boom vs . probe and drogue – is a key...flight, which can add considerable flexibility to certain air operations. Boom vs . Probe and Drogue Air Refueling.32 Aircraft can be equipped to be

An overview of the 2013 Las Vegas Ozone Study (LVOS): Impact of stratospheric intrusions and long-range transport on surface air quality

NASA Astrophysics Data System (ADS)

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

2015-05-01

The 2013 Las Vegas Ozone Study (LVOS) was conducted in the late spring and early summer of 2013 to assess the seasonal contribution of stratosphere-to-troposphere transport (STT) and long-range transport to surface ozone in Clark County, Nevada and determine if these processes directly contribute to exceedances of the National Ambient Air Quality Standard (NAAQS) in this area. Secondary goals included the characterization of local ozone production, regional transport from the Los Angeles Basin, and impacts from wildfires. The LVOS measurement campaign took place at a former U.S. Air Force radar station ∼45 km northwest of Las Vegas on Angel Peak (∼2.7 km above mean sea level, asl) in the Spring Mountains. The study consisted of two extended periods (May 19-June 4 and June 22-28, 2013) with near daily 5-min averaged lidar measurements of ozone and backscatter profiles from the surface to ∼2.5 km above ground level (∼5.2 km asl), and continuous in situ measurements (May 20-June 28) of O3, CO, (1-min) and meteorological parameters (5-min) at the surface. These activities were guided by forecasts and analyses from the FLEXPART (FLEXible PARTticle) dispersion model and the Real Time Air Quality Modeling System (RAQMS), and the NOAA Geophysical Research Laboratory (NOAA GFDL) AM3 chemistry-climate model. In this paper, we describe the LVOS measurements and present an overview of the results. The combined measurements and model analyses show that STT directly contributed to each of the three O3 exceedances that occurred in Clark County during LVOS, with contributions to 8-h surface concentrations in excess of 30 ppbv on each of these days. The analyses show that long-range transport from Asia made smaller contributions (<10 ppbv) to surface O3 during two of those exceedances. The contribution of regional wildfires to surface O3 during the three LVOS exceedance events was found to be negligible, but wildfires were found to be a major factor during exceedance events that occurred before and after the LVOS campaign. Our analyses also shows that ozone exceedances would have occurred on more than 50% of the days during the six-week LVOS campaign if the 8-h ozone NAAQS had been 65 ppbv instead of 75 ppbv.

Disturbances to Air-Layer Skin-Friction Drag Reduction at High Reynolds Numbers

NASA Astrophysics Data System (ADS)

Dowling, David; Elbing, Brian; Makiharju, Simo; Wiggins, Andrew; Perlin, Marc; Ceccio, Steven

2009-11-01

Skin friction drag on a flat surface may be reduced by more than 80% when a layer of air separates the surface from a flowing liquid compared to when such an air layer is absent. Past large-scale experiments utilizing the US Navy's Large Cavitation Channel and a flat-plate test model 3 m wide and 12.9 m long have demonstrated air layer drag reduction (ALDR) on both smooth and rough surfaces at water flow speeds sufficient to reach downstream-distance-based Reynolds numbers exceeding 100 million. For these experiments, the incoming flow conditions, surface orientation, air injection geometry, and buoyancy forces all favored air layer formation. The results presented here extend this prior work to include the effects that vortex generators and free stream flow unsteadiness have on ALDR to assess its robustness for application to ocean-going ships. Measurements include skin friction, static pressure, airflow rate, video of the flow field downstream of the injector, and profiles of the flowing air-water mixture when the injected air forms bubbles, when it is in transition to an air layer, and when the air layer is fully formed. From these, and the prior measurements, ALDR's viability for full-scale applications is assessed.

Study of surface atmospheric pressure glow discharge plasma based on ultrathin laminated electrodes in air

NASA Astrophysics Data System (ADS)

Zhao, Luxiang; Liu, Wenzheng; Li, Zhiyi; Ma, Chuanlong

2018-05-01

A method to generate large-area surface plasma in air by micro-discharge is proposed. Two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer. The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation. In particular, the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased, and the treated objects can be prevented from metal ion pollution caused by the electrode in the discharge. It has broad application prospects in the fields of aerodynamics and material surface treatment.

Ultraviolet-Ozone Cleaning of Semiconductor Surfaces

DTIC Science & Technology

1992-10-01

rooms and in the air ducts of air conditioning systems (7). In 1972, Bolon and Kunz (1) reported that UV light had the capability to depolymerize a...instead of oxygen, the depolymerization was hindered. Thus, Bolon and Kunz recognized that oxygen and wavelengths shorter than 300-nm played a role in the...that mild heat increases the UV/ozone cleaning rates. Bolon and Kunz (1), on the other hand, found that the rate of ozone depolymerization of

The nature of the air-cleaved mica surface

NASA Astrophysics Data System (ADS)

Christenson, Hugo K.; Thomson, Neil H.

2016-06-01

The accepted image of muscovite mica is that of an inert and atomically smooth surface, easily prepared by cleavage in an ambient atmosphere. Consequently, mica is extensively used a model substrate in many fundamental studies of surface phenomena and as a substrate for AFM imaging of biomolecules. In this review we present evidence from the literature that the above picture is not quite correct. The mica used in experimental work is almost invariably cleaved in laboratory air, where a reaction between the mica surface, atmospheric CO2 and water occurs immediately after cleavage. The evidence suggests very strongly that as a result the mica surface becomes covered by up to one formula unit of K2CO3 per nm2, which is mobile under humid conditions, and crystallises under drier conditions. The properties of mica in air or water vapour cannot be fully understood without reference to the surface K2CO3, and many studies of the structure of adsorbed water on mica surfaces may need to be revisited. With this new insight, however, the air-cleaved mica should provide exciting opportunities to study phenomena such as two-dimensional ion diffusion, electrolyte effects on surface conductivity, and two-dimensional crystal nucleation.

Ceramic membrane defouling (cleaning) by air Nano Bubbles.

PubMed

Ghadimkhani, Aliasghar; Zhang, Wen; Marhaba, Taha

2016-03-01

Ceramic membranes are among the most promising technologies for membrane applications, owing to their excellent resistance to mechanical, chemical, and thermal stresses. However, membrane fouling is still an issue that hampers the applications at large scales. Air Nano Bubbles (NBs), due to high mass transfer efficiency, could potentially prevent fouling of ceramic membrane filtration processes. In this study, bench and pilot scale ceramic membrane filtration was performed with air NBs to resist fouling. To simulate fouling, humic acid, as an organic foulant, was applied to the membrane flat sheet surface. Complete membrane clogging was achieved in less than 6 h. Membrane defouling (cleaning) was performed by directly feeding of air NBs to the membrane cells. The surface of the ceramic membrane was superbly cleaned by air NBs, as revealed by atomic force microscope (AFM) images before and after the treatment. The permeate flux recovered to its initial level (e.g., 26.7 × 10(-9) m(3)/m(2)/s at applied pressure of 275.8 kPa), which indicated that NBs successfully unclogged the pores of the membrane. The integrated ceramic membrane and air NBs system holds potential as an innovative sustainable technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling green infrastructure land use changes on future air ...

EPA Pesticide Factsheets

Green infrastructure can be a cost-effective approach for reducing stormwater runoff and improving water quality as a result, but it could also bring co-benefits for air quality: less impervious surfaces and more vegetation can decrease the urban heat island effect, and also result in more removal of air pollutants via dry deposition with increased vegetative surfaces. Cooler surface temperatures can also decrease ozone formation through the increases of NOx titration; however, cooler surface temperatures also lower the height of the boundary layer resulting in more concentrated pollutants within the same volume of air, especially for primary emitted pollutants (e.g. NOx, CO, primary particulate matter). To better understand how green infrastructure impacts air quality, the interactions between all of these processes must be considered collectively. In this study, we use a comprehensive coupled meteorology-air quality model (WRF-CMAQ) to simulate the influence of planned land use changes that include green infrastructure in Kansas City (KC) on regional meteorology and air quality. Current and future land use data was provided by the Mid-America Regional Council for 2012 and 2040 (projected land use due to population growth, city planning and green infrastructure implementation). These land use datasets were incorporated into the WRF-CMAQ modeling system allowing the modeling system to propagate the changes in vegetation and impervious surface coverage on meteoro

Defences against ammonia toxicity in tropical air-breathing fishes exposed to high concentrations of environmental ammonia: a review.

PubMed

Ip, Y K; Chew, S F; Wilson, J M; Randall, D J

2004-10-01

In the tropics, air-breathing fishes can be exposed to environmental ammonia when stranded in puddles of water during the dry season, during a stay inside a burrow, or after agricultural fertilization. At low concentrations of environmental ammonia, NH(3) excretion is impeded, as in aerial exposure, leading to the accumulation of endogenous ammonia. At high concentrations of environmental ammonia, which results in a reversed NH(3) partial pressure gradient (DeltaP(NH3)), there is retention of endogenous ammonia and uptake of exogenous ammonia. In this review, several tropical air-breathing fishes (giant mudskipper, African catfish, oriental weatherloach, swamp eel, four-eyed sleeper, abehaze and slender African lungfish), which can tolerate high environmental ammonia exposure, are used as examples to demonstrate how eight different adaptations can be involved in defence against ammonia toxicity. Four of these adaptations deal with ammonia toxicity at branchial and/or epithelial surfaces: (1) active excretion of NH(4)(+); (2) lowering of environmental pH; (3) low NH(3) permeability of epithelial surfaces; and (4) volatilization of NH(3), while another four adaptations ameliorate ammonia toxicity at the cellular and subcellular levels: (5) high tolerance of ammonia at the cellular and subcellular levels; (6) reduction in ammonia production; (7) glutamine synthesis; and (8) urea synthesis. The responses of tropical air-breathing fishes to high environmental ammonia are determined apparently by behavioural adaptations and the nature of their natural environments.

Can air temperatures be used to project influences of climate change on stream temperatures?

NASA Astrophysics Data System (ADS)

Arismendi, I.; Safeeq, M.; Dunham, J.; Johnson, S. L.

2013-12-01

The lack of available in situ stream temperature records at broad spatiotemporal scales have been recognized as a major limiting factor in the understanding of thermal behavior of stream and river systems. This has motivated the promotion of a wide variety of models that use surrogates for stream temperatures including a regression approach that uses air temperature as the predictor variable. We investigate the long-term performance of widely used linear and non-linear regression models between air and stream temperatures to project the latter in future climate scenarios. Specifically, we examine the temporal variability of the parameters that define each of these models in long-term stream and air temperature datasets representing relatively natural and highly human-influenced streams. We selected 25 sites with long-term records that monitored year-round daily measurements of stream temperature (daily mean) in the western United States (California, Oregon, Idaho, Washington, and Alaska). Surface air temperature data from each site was not available. Therefore, we calculated daily mean surface air temperature for each site in contiguous US from a 1/16-degree resolution gridded surface temperature data. Our findings highlight several limitations that are endemic to linear or nonlinear regressions that have been applied in many recent attempts to project future stream temperatures based on air temperature. Our results also show that applications over longer time periods, as well as extrapolation of model predictions to project future stream temperatures are unlikely to be reliable. Although we did not analyze a broad range of stream types at a continental or global extent, our analysis of stream temperatures within the set of streams considered herein was more than sufficient to illustrate a number of specific limitations associated with statistical projections of stream temperature based on air temperature. Radar plots of Nash-Sutcliffe efficiency (NSE) values for the two correlation models in regulated (n=14; lower panel) and unregulated (n=11; upper panel) streams. Solid lines represent average × SD of the NSE estimated for different time periods every 5-year. Dotted line at each plot indicates a NSE = 0.7. Symbols outside of the dotted line at each plot represent a satisfactory level of accuracy of the model

Experimental Investigation of Centrifugal Compressor Stabilization Techniques

NASA Technical Reports Server (NTRS)

Skoch, Gary J.

2003-01-01

Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste

2010-01-01

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best on the average from the perspective of improving Global 7 day forecast skill.

Surface analysis of mixed-conducting ferrite membranes by the conversion-electron Mössbauer spectroscopy

NASA Astrophysics Data System (ADS)

Waerenborgh, J. C.; Tsipis, E. V.; Yaremchenko, A. A.; Kharton, V. V.

2011-09-01

Conversion-electron Mössbauer spectroscopy analysis of iron surface states in the dense ceramic membranes made of 57Fe-enriched SrFe 0.7Al 0.3O 3- δ perovskite, shows no traces of reductive decomposition or carbide formation in the interfacial layers after operation under air/CH 4 gradient at 1173 K, within the limits of experimental uncertainty. The predominant trivalent state of iron cations at the membrane permeate-side surface exposed to flowing dry methane provides evidence of the kinetic stabilization mechanism, which is only possible due to slow oxygen-exchange kinetics and enables long-term operation of the ferrite-based ceramic reactors for natural gas conversion. At the membrane feed-side surface exposed to air, the fractions of Fe 4+ and Fe 3+ are close to those in the powder equilibrated at atmospheric oxygen pressure, suggesting that the exchange limitations to oxygen transport are essentially localized at the partially reduced surface.

Laser-induced plasmas in air studied using two-color interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zefeng; Wu, Jian, E-mail: jxjawj@mail.xjtu.edu.cn; Li, Xingwen

2016-08-15

Temporally and spatially resolved density profiles of Cu atoms, electrons, and compressed air, from laser-induced copper plasmas in air, are measured using fast spectral imaging and two-color interferometry. From the intensified CCD images filtered by a narrow-band-pass filter centered at 515.32 nm, the Cu atoms expansion route is estimated and used to determine the position of the fracture surface between the Cu atoms and the air. Results indicate that the Cu atoms density at distances closer to the target (0–0.4 mm) is quite low, with the maximum density appearing at the edge of the plasma's core being ∼4.6 × 10{sup 24 }m{sup −3} at 304 ns.more » The free electrons are mainly located in the internal region of the plume, which is supposed to have a higher temperature. The density of the shock wave is (4–6) × 10{sup 25 }m{sup −3}, corresponding to air compression of a factor of 1.7–2.5.« less

Aerial Neutron Detection of Cosmic-Ray Interactions with the Earth's Surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard Maurer

2008-09-18

We have demonstrated the ability to measure the neutron flux produced by the cosmic-ray interaction with nuclei in the ground surface using aerial neutron detection. High energy cosmic-rays (primarily muons with GeV energies) interact with the nuclei in the ground surface and produce energetic neutrons via spallation. At the air-surface interface, the neutrons produced by spallation will either scatter within the surface material, become thermalized and reabsorbed, or be emitted into the air. The mean free path of energetic neutrons in air can be hundreds of feet as opposed to a few feet in dense materials. As such, the fluxmore » of neutrons escaping into the air provides a measure of the surface nuclei composition. It has been demonstrated that this effect can be measured at long range using neutron detectors on low flying helicopters. Radiological survey measurements conducted at Government Wash in Las Vegas, Nevada, have shown that the neutron background from the cosmic-soil interactions is repeatable and directly correlated to the geological data. Government Wash has a very unique geology, spanning a wide variety of nuclide mixtures and formations. The results of the preliminary measurements are presented.« less

The homestake surface-underground scintillators: Initial results

NASA Technical Reports Server (NTRS)

Cherry, M. L.; Corbato, S.; Daily, T.; Fenyves, E. J.; Kieda, D.; Lande, K.; Lee, C. K.

1986-01-01

The first 70 tons of the 140-ton Large Area Scintillation Detector (LASD) have been operating since Jan. 1985 at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine, Lead, S.D. A total of 4 x 10(4) high-energy muons (E sub mu is approx. 2.7 TeV at the surface) have been detected. The remainder of the detector is scheduled to be in operation by the Fall of 1985. In addition, a surface air shower array is under construction. The first 27 surface counters, spaced out over an area of 270' x 500', began running in June, 1985. The LASD performance, the potential of the combined shower array and underground muon experiment for detecting point sources, and the initial results of a search for periodic emission from Cygnus X-3 are discussed.

Incommensurate smectic order at the free surface in the nematic phase of 4-n-heptylphenyl-4'-(4''-nitrobenzoyloxy)benzoate (DB7NO2)

NASA Astrophysics Data System (ADS)

Ocko, B. M.; Pershan, P. S.; Safinya, C. R.; Chiang, L. Y.

1987-02-01

We report x-ray reflectivity measurements on the free surface of 4-n-heptylphenyl-4'-(4''-nitrobenzoyloxy)benzoate (DB7NO2) at the nematic to smectic-A phase transition, TNA=99.9 °C. The free surface in the nematic phase exhibits smecticlike ordering at two q vectors, one which is commensurate with the smectic-A monolayer q vector q2. The other q vector is incommensurate corresponding to ordering at ~0.59q2. The commensurate peak constructively interferes with the air-liquid interface while the incommensurate peak destructively interferes. These results are compared with bulk-phase x-ray scattering measurements.

Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

NASA Technical Reports Server (NTRS)

Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

2016-01-01

This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

Physical-mechanical image of the cell surface on the base of AFM data in contact mode

NASA Astrophysics Data System (ADS)

Starodubtseva, M. N.; Starodubtsev, I. E.; Yegorenkov, N. I.; Kuzhel, N. S.; Konstantinova, E. E.; Chizhik, S. A.

2017-10-01

Physical and mechanical properties of the cell surface are well-known markers of a cell state. The complex of the parameters characterizing the cell surface properties, such as the elastic modulus (E), the parameters of adhesive (Fa), and friction (Ff) forces can be measured using atomic force microscope (AFM) in a contact mode and form namely the physical-mechanical image of the cell surface that is a fundamental element of the cell mechanical phenotype. The paper aims at forming the physical-mechanical images of the surface of two types of glutaraldehyde-fixed cancerous cells (human epithelial cells of larynx carcinoma, HEp-2c cells, and breast adenocarcinoma, MCF-7 cells) based on the data obtained by AFM in air and revealing the basic difference between them. The average values of friction, elastic and adhesive forces, and the roughness of lateral force maps, as well as dependence of the fractal dimension of lateral force maps on Z-scale factor have been studied. We have revealed that the response of microscale areas of the HEp-2c cell surface having numerous microvilli to external mechanical forces is less expressed and more homogeneous in comparison with the response of MCF-7 cell surface.

Hybrid Eulerian and Lagrangian Simulation of Steep and Breaking Waves and Surface Fluxes in High Winds

DTIC Science & Technology

2012-09-30

Lagrangian methods for free - surface turbulence and wave simulation . In the far field, coupled wind and wave simulations are used to obtain wind...to conserve the mass precisely. When the wave breaks, the flow at the free surface may become very violent, air and water may be highly mixed...fluids free - surface flows that can be used to study the fundamental physics of wave breaking. The research will improve the understanding of air-sea

Analysis of health data from 10 years of Polaris submarine patrols.

PubMed

Tansey, W A; Wilson, J M; Schaefer, K E

1979-01-01

Medical reports from 885 Fleet Ballistic Missile (FBM) submarine patrols (7,650,000 man-days) were analyzed. The data were categorized and compared with data obtained by medical personnel from surface fleet personnel (1,215,918 man-days) during a continuous 7--8 months' deployment of surface vessels in 1973. Surface fleet personnel had a higher illness rate in the categories of respiratory, traumatic, gastrointestinal, dermal, infections, and miscellaneous illness, and a lower rate in genitourinary, systemic (including mononucleosis), cranial, and neuropsychiatric illness compared to submarine personnel. Because of improved atmosphere control, a sharp decline in the level of submarine contaminants occurred between 1965--67. Reports from the 1968--73 period showed a decrease in: 1) respiratory; 2) ear, nose, and throat; 3) gastrointestinal; 4) cardiovascular; 5) urologic; and 6) general medical illness categories; the number of general surgery, orthopedics, dental, and eye illness cases was not affected. Neurologic and psychiatric disease showed the only increases in incidence for this period. The overall decrease in illness can be attributed mainly to the fall in the incidence of respiratory disease, known to be affected by reduced air pollution, and the decline in gastrointestinal illness. This decline occurred in a period during which the incidence of both classes of illness went up in the general population, according to the Health Interview Survey published by DHEW. The improvement of atmosphere control in submarines caused a substantial reduction in contaminants (a decline in tobacco smoking also occurred in this period), which led to a decrease in incidence of illness, particularly respiratory disease. No direct causal relationship between reduction in air pollution and reduction in the incidence of disease could be proven within the framework of this study, however.

Simulation of trace metals and PAH atmospheric pollution over Greater Paris: Concentrations and deposition on urban surfaces

NASA Astrophysics Data System (ADS)

Thouron, L.; Seigneur, C.; Kim, Y.; Legorgeu, C.; Roustan, Y.; Bruge, B.

2017-10-01

Urban areas can be subject not only to poor air quality, but also to contamination of other environmental media by air pollutants. Here, we address the potential transfer of selected air pollutants (two metals and three PAH) to urban surfaces. To that end, we simulate meteorology and air pollution from Europe to a Paris suburban neighborhood, using a four-level one-way nesting approach. The meteorological and air quality simulations use urban canopy sub-models in order to better represent the effect of the urban morphology on the air flow, atmospheric dispersion, and deposition of air pollutants to urban surfaces. This modeling approach allows us to distinguish air pollutant deposition among various urban surfaces (roofs, roads, and walls). Meteorological model performance is satisfactory, showing improved results compared to earlier simulations, although precipitation amounts are underestimated. Concentration simulation results are also satisfactory for both metals, with a fractional bias <0.5. Concentrations of benzo[a]pyrene are overestimated, probably because continental emissions may be overestimated. Concentrations of benzo[b]fluoranthene and indeno[1,2,3,cd]pyrene are underestimated, in part because of null boundary conditions. PAH deposition fluxes are consistent with earlier measurements obtained in the Greater Paris region. The model simulation results suggest that both wet and dry deposition processes need to be considered when estimating the transfer of air pollutants to other environmental media. Dry deposition fluxes to various urban surfaces are mostly uniform for PAH, which are entirely present in fine particles. However, there is significantly less wall deposition compared to deposition to roofs and roads for trace metals, due to their coarse fraction. Meteorology, particle size distribution, and urban morphology are all important factors affecting air pollutant deposition. Future work should focus on the collection of data suitable to evaluate the performance of atmospheric models for both wet and dry deposition with fine spatial resolution.

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. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Phase transition of LB films of mixed diblock copolymer at the air/water interface

NASA Astrophysics Data System (ADS)

Seo, Y. S.; Kim, K. S.; Samuilov, V.; Rafailovich, M. H.; Sokolov, J.; Lammertink, Rob G. H.; Vancso, G. J.

2000-03-01

We have studied the morphology of Langmuir blodgett films at the air/water interface of mixed diblock copolymer films. Solutions of poly(styrene-b-ferrocenyldimethylsilane) and PS-b-P2VP mixed in a ratio of 20/80 in chloroform were spread at the air/water interface. The morphology of the films was studied with AFM as a function of the surface pressure and the diblock copolymer molecular weight. The results show that the two diblock copolymers can be induced to mix at the air/water interface with increasing surface pressure. A reversible transition from spherical to cylindrical morphologies is induced in the mixture which can not be observed in films formed of the two components separately. The effective surface phase diagram as a function of block copolymer composition and pressure will be presented.

Polydopamine-reinforced magnetization of zeolitic imidazolate framework ZIF-7 for magnetic solid-phase extraction of polycyclic aromatic hydrocarbons from the air-water environment.

PubMed

Zhang, Suling; Yao, Weixuan; Ying, Jianbo; Zhao, Hongting

2016-06-24

Zeolitic imidazolate frameworks (ZIFs) consist of metal nodes connected to imidazolate linkers, having both the properties of metal-organic frameworks (MOFs) and inorganic zeolites, such as controllable pore sizes, high porosity and surface areas, as well as exceptional thermal and chemical stability, thereby making them a class of attractive materials for diverse analytical applications. In this study, we reported a facile magnetization process of ZIF-7 (zinc benzimidazolate) for simultaneous magnetic extraction of polycyclic aromatic hydrocarbons (PAHs) by simply mixing ZIF-7 and polydopamine (PDA)-coated Fe3O4 nanoparticles (PDA@Fe3O4) in solutions. Functional groups (-OH and -NH2), provided by PDA as a highly efficient molecular linker, could attract and anchor ZIF-7 through noncovalent adsorption and covalent cross-link interactions, thereby promoting the complete magnetization of ZIFs and enhancing their stability and reusability. The bridging ligand benzimidazolate, could be bonded with PAHs because of its high surface area, large pores, accessible coordinative unsaturated sites (π-complexation), and π-π stacking action. This ZIF-based magnetic solid-phase extraction (SPE), coupled with gas chromatography/tandem mass spectrometry (GC/MS), was further evaluated for analysis of PAHs from rainwater and air samples of particulate matter less than 2.5μm in diameter (PM2.5). The main effective parameters, including ionic strength, solution pH, extraction time, desorption solvent and desorption time, were investigated, respectively. Under optimized conditions, the developed method based on Fe3O4@PDA/ZIF-7 gave detection limits of 0.71-5.79ng/L, and quantification limits of 2.50-19.2ng/L for PAHs, respectively. The relative standard deviations for intra-day and inter-day analyses were in the range of 3.1-9.1% and 6.1-12.7%, respectively. The PAHs founded in PM2.5 were in the range of 0.40-6.79ng/m(3). Good recoveries (>82%) with low relative standard deviations (≤9.2%) were achieved. This method was demonstrated to be an accurate, convenient and sensitive pretreatment procedure for trace analysis of environmental water and air samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Implement a Sub-grid Turbulent Orographic Form Drag in WRF and its application to Tibetan Plateau

NASA Astrophysics Data System (ADS)

Zhou, X.; Yang, K.; Wang, Y.; Huang, B.

2017-12-01

Sub-grid-scale orographic variation exerts turbulent form drag on atmospheric flows. The Weather Research and Forecasting model (WRF) includes a turbulent orographic form drag (TOFD) scheme that adds the stress to the surface layer. In this study, another TOFD scheme has been incorporated in WRF3.7, which exerts an exponentially decaying drag on each model layer. To investigate the effect of the new scheme, WRF with the old and new one was used to simulate the climate over the complex terrain of the Tibetan Plateau. The two schemes were evaluated in terms of the direct impact (on wind) and the indirect impact (on air temperature, surface pressure and precipitation). Both in winter and summer, the new TOFD scheme reduces the mean bias in the surface wind, and clearly reduces the root mean square error (RMSEs) in comparisons with the station measurements (Figure 1). Meanwhile, the 2-m air temperature and surface pressure is also improved (Figure 2) due to the more warm air northward transport across south boundary of TP in winter. The 2-m air temperature is hardly improved in summer but the precipitation improvement is more obvious, with reduced mean bias and RMSEs. This is due to the weakening of water vapor flux (at low-level flow with the new scheme) crossing the Himalayan Mountains from South Asia.

Intercomparison of Recent Anomaly Time-Series of OLR as Observed by CERES and Computed Using AIRS Products

NASA Technical Reports Server (NTRS)

Susskind, Joel; Molnar, Gyula; Iredell, Lena; Loeb, Norman G.

2011-01-01

This paper compares recent spatial and temporal anomaly time series of OLR as observed by CERES and computed based on AIRS retrieved surface and atmospheric geophysical parameters over the 7 year time period September 2002 through February 2010. This time period is marked by a substantial decrease of OLR, on the order of +/-0.1 W/sq m/yr, averaged over the globe, and very large spatial variations of changes in OLR in the tropics, with local values ranging from -2.8 W/sq m/yr to +3.1 W/sq m/yr. Global and Tropical OLR both began to decrease significantly at the onset of a strong La Ni a in mid-2007. Late 2009 is characterized by a strong El Ni o, with a corresponding change in sign of both Tropical and Global OLR anomalies. The spatial patterns of the 7 year short term changes in AIRS and CERES OLR have a spatial correlation of 0.97 and slopes of the linear least squares fits of anomaly time series averaged over different spatial regions agree on the order of +/-0.01 W/sq m/yr. This essentially perfect agreement of OLR anomaly time series derived from observations by two different instruments, determined in totally independent and different manners, implies that both sets of results must be highly stable. This agreement also validates the anomaly time series of the AIRS derived products used to compute OLR and furthermore indicates that anomaly time series of AIRS derived products can be used to explain the factors contributing to anomaly time series of OLR.

Final Environmental Assessment: Proposed Fire Crash Rescue Station, Hill Air Force Base, Utah

DTIC Science & Technology

2008-10-02

storage shed (Building 16) would be demolished and converted to parking ( see Figure 1 for the approximate locations). 1.3 Need for the Action The...existing facilities ( see Section 2.3.3.1), and other potential locations for siting the proposed fire crash rescue station ( see Section 2.3.3.2). 2.3...during scoping meetings, but eliminated from detailed consideration ( see Section 1.7.3) include: • geology and surface soils (seismicity, topography

33 CFR 334.200 - Chesapeake Bay, Point Lookout to Cedar Point; aerial and surface firing range and target area, U...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cedar Point; aerial and surface firing range and target area, U.S. Naval Air Station, Patuxent River... Chesapeake Bay, Point Lookout to Cedar Point; aerial and surface firing range and target area, U.S. Naval Air...) The regulations. (i) Through navigation of surface craft outside the target areas will be permitted at...

Corneal Sensitivity in Tear Dysfunction and its Correlation with Clinical Parameters and Blink Rate

PubMed Central

Rahman, Effie Z.; Lam, Peter K.; Chu, Chia-Kai; Moore, Quianta; Pflugfelder, Stephen C.

2015-01-01

Purpose To compare corneal sensitivity in tear dysfunction due to a variety of causes using contact and non-contact esthesiometers and to evaluate correlations between corneal sensitivity, blink rate and clinical parameters. Design Comparative observational case series. Methods Ten normal and 33 subjects with tear dysfunction [meibomian gland disease (n = 11), aqueous tear deficiency (n = 10) - without (n = 7) and with (n = 3) Sjögren syndrome (SS) and conjunctivochalasis (n = 12)] were evaluated. Corneal sensitivity was measured with Cochet-Bonnet and air jet esthesiometers and blink rate by electromyelography. Eye irritation symptoms, tear meniscus height, tear break-up time (TBUT), and corneal and conjunctival dye staining were measured. Between group means were compared and correlations calculated. Results Compared with control (Cochet-Bonnet 5.45 mm, air esthesiometer 3.62 mg), mean sensory thresholds were significantly higher in aqueous tear deficiency using either Cochet-Bonnet (3.6 mm; P = 0.003) or air (11.7 mg; P = 0.046) esthesiometers, but were not significantly different in the other groups. Reduced corneal sensitivity significantly correlated with more rapid TBUT and blink rate, and greater irritation and ocular surface dye staining with one or both esthesiometers. Mean blink rates were significantly higher in both aqueous tear deficiency and conjunctivochalasis compared with control. Among all subjects, blink rate positively correlated with ocular surface staining and irritation and inversely correlated with TBUT. Conclusion Amongst conditions causing tear dysfunction, reduced corneal sensitivity is associated with greater irritation, tear instability, ocular surface disease and blink rate. Rapid blinking is associated with worse ocular surface disease and tear stability. PMID:26255576

On the evaluation of air mass factors for atmospheric near-ultraviolet and visible absorption spectroscopy

NASA Technical Reports Server (NTRS)

Perliski, Lori M.; Solomon, Susan

1993-01-01

The interpretation of UV-visible twilight absorption measurements of atmospheric chemical constituents is dependent on how well the optical path, or air mass factor, of light collected by the spectrometer is understood. A simple single scattering model and a Monte Carlo radiative transfer scheme have been developed to study the effects of multiple scattering, aerosol scattering, surface albedo and refraction on air mass factors for scattered light observations. At fairly short visible wavelengths (less than about 450 nm), stratospheric air mass factors are found to be relatively insensitive to multiple scattering, surface albedo and refraction, as well as aerosol scattering by background aerosols. Longer wavelengths display greater sensitivity to refraction and aerosol scattering. Tropospheric air mass factors are found to be highly dependent on aerosol scattering, surface albedo and, at long visible wavelengths (about 650 nm), refraction. Absorption measurements of NO2 and O4 are shown to support these conclusions.

Local climate change induced by groundwater overexploitation in a high Andean arid watershed, Laguna Lagunillas basin, northern Chile

NASA Astrophysics Data System (ADS)

Scheihing, Konstantin; Tröger, Uwe

2018-05-01

The Laguna Lagunillas basin in the arid Andes of northern Chile exhibits a shallow aquifer and is exposed to extreme air temperature variations from 20 to -25 °C. Between 1991 and 2012, groundwater levels in the Pampa Lagunillas aquifer fell from near-surface to 15 m below ground level (bgl) due to severe overexploitation. In the same period, local mean monthly minimum temperatures started a declining trend, dropping by 3-8 °C relative to a nearby reference station. Meanwhile, mean monthly maximum summer temperatures shifted abruptly upwards by 2.7 °C on average in around 1996. The observed air temperature downturns and upturns are in accordance with detected anomalies in land-surface temperature imagery. Two major factors may be causing the local climate change. One is related to a water-table decline below the evaporative energy potential extinction depth of 2 m bgl, which causes an up-heating of the bare soil surface and, in turn, influences the lower atmosphere. At the same time, the removal of near-surface groundwater reduces the thermal conductivity of the upper sedimentary layer, which consequently diminishes the heat exchange between the aquifer (constant heat source of 10 °C) and the lower atmosphere during nights, leading to a severe dropping of minimum air temperatures. The observed critical water-level drawdown was 2-3 m bgl. Future and existing water-production projects in arid high Andean basins with shallow groundwater should avoid a decline of near-surface groundwater below 2 m bgl and take groundwater-climate interactions into account when identifying and monitoring potential environmental impacts.

The effect of different cleaning methods on the surface and temperature of failed titanium implants: an in vitro study.

PubMed

Hakki, Sema S; Tatar, Gulsah; Dundar, Niyazi; Demiralp, Burak

2017-04-01

The aims of this in vitro study are to compare the efficacy of different cleaning methods in removing debris of failed implants and to detect thermal changes of the implants treated by various scaling instruments. Twenty-seven failed implants and two unused implants as control were included to this study-group 1: plastic curette (P), group 2: titanium curette (T), group 3: carbon curette (C), group 4: titanium brush (TB), group 5: Er:YAG laser (laser 1 (L1) 100 mJ/pulse at 10 Hz), group 6: Er:YAG laser (laser 2 (L2) 150 mJ/pulse at 10 Hz), group 7: Er:YAG laser (laser 3 (L3) 200 mJ/pulse at 10 Hz), group 8: ultrasonic scaler appropriate for titanium (US), group 9: air abrasive method (AA) + citric acid, and group 10: implantoplasty (I). The changes on the treated/untreated titanium surfaces and remnant debris were observed by scanning electron microscopy (SEM). Temperature of the implants before and after treatment was detected using a thermocouple. The use of air abrasive and citric acid combination and Er:YAG laser groups was found as the best methods for the decontamination of titanium surfaces of failed implant. When the hand instruments were compared, titanium curette was found better than both the plastic and the carbon curettes which leave plastics and carbon remnants on the titanium surface. The temperature was higher after hand instrumentation when compared to other experimental groups (p < 0.05). Within the limitations of the present in vitro model, it can be concluded that the best method for decontamination of the implant surface is the use of air abrasives and Er:YAG laser.

30 CFR 57.5006 - Air Quality-Surface Only [Reserved

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Air Quality-Surface Only [Reserved] 57.5006... Quality, Radiation, Physical Agents, and Diesel Particulate Matter Air Quality-Surface and Underground...-Nitrosodimethylamine. Air Quality—Surface Only [Reserved] Air Quality—Underground Only ...

30 CFR 57.5006 - Air Quality-Surface Only [Reserved

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Air Quality-Surface Only [Reserved] 57.5006... Quality, Radiation, Physical Agents, and Diesel Particulate Matter Air Quality-Surface and Underground...-Nitrosodimethylamine. Air Quality—Surface Only [Reserved] Air Quality—Underground Only ...

30 CFR 57.5006 - Air Quality-Surface Only [Reserved

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Air Quality-Surface Only [Reserved] 57.5006... Quality, Radiation, Physical Agents, and Diesel Particulate Matter Air Quality-Surface and Underground...-Nitrosodimethylamine. Air Quality—Surface Only [Reserved] Air Quality—Underground Only ...

Environmental monitoring of carbaryl applied in urban areas to control the glassy-winged sharpshooter in California.

PubMed

Walters, Johanna; Goh, Kean S; Li, Linying; Feng, Hsiao; Hernandez, Jorge; White, Jane

2003-03-01

Carbaryl insecticide was applied by ground spray to plants in urban areas to control a serious insect pest the glassy-winged sharpshooter, Homalodisca coagulata (Say), newly introduced in California. To assure there are no adverse impacts to human health and the environment from the carbaryl applications, carbaryl was monitored in tank mixtures, air, surface water, foliage and backyard fruits and vegetables. Results from the five urban areas - Porterville, Fresno, Rancho Cordova, Brentwood and Chico - showed there were no significant human exposures or impacts on the environment. Spray tank concentrations ranged from 0.1-0.32%. Carbaryl concentrations in air ranged from none detected to 1.12 microg m(-3), well below the interim health screening level in air of 51.7 microg m(-3). There were three detections of carbaryl in surface water near application sites: 0.125 ppb (parts per billion) from a water treatment basin; 6.94 ppb from a gold fish pond; and 1737 ppb in a rain runoff sample collected from a drain adjacent to a sprayed site. The foliar dislodgeable residues ranged from 1.54-7.12 microg cm(-2), comparable to levels reported for safe reentry of 2.4 to 5.6 microg cm(-2) for citrus. Carbaryl concentrations in fruits and vegetables ranged from no detectable amounts to 7.56 ppm, which were below the U.S. EPA tolerance, allowable residue of 10 ppm.

Control of membrane permeability in air-stable droplet interface bilayers

DOE PAGES

Mruetusatorn, Prachya; Polizos, Georgios; Datskos, Panos G.; ...

2015-03-19

Air-stable droplet interface bilayers (airDIBs) on oil-infused surfaces are versatile model membranes for synthetic biology applications, including biosensing of airborne species. However, air-DIBs are subject to evaporation, which can, over time, destabilize them and reduce their useful lifetime compared to traditional DIBs that are fully submerged in oil. Here, we show that lifetimes of air-DIBs can be extended by as much as an order of magnitude by maintaining them at a temperature just above the dew point. We find that raising the temperature from near the dew point (7 C at 38.5 % relative humidity) to room temperature results inmore » loss of water molecules of hydration from the polar head groups of the lipid bilayer membrane due to evaporation in an irreversible process that increases the overall entropy of the system. This dehydration transition affects primarily the bilayer resistance, by increasing ion permeability through the increasingly disordered polar head group region of the bilayer. Temperature and/or relative humidity are conveniently tunable parameters for controlling the stability and composition of air-DIBs membranes, while still allowing for operation in ambient environments.« less

Impacts of Ozone-vegetation Interactions and Biogeochemical Feedbacks on Atmospheric Composition and Air Quality Under Climate Change

NASA Astrophysics Data System (ADS)

Sadeke, M.; Tai, A. P. K.; Lombardozzi, D.; Val Martin, M.

2015-12-01

Surface ozone pollution is one of the major environmental concerns due to its damaging effects on human and vegetation. One of the largest uncertainties of future surface ozone prediction comes from its interaction with vegetation under a changing climate. Ozone can be modulated by vegetation through, e.g., biogenic emissions, dry deposition and transpiration. These processes are in turn affected by chronic exposure to ozone via lowered photosynthesis rate and stomatal conductance. Both ozone and vegetation growth are expected to be altered by climate change. To better understand these climate-ozone-vegetation interactions and possible feedbacks on ozone itself via vegetation, we implement an online ozone-vegetation scheme [Lombardozzi et al., 2015] into the Community Earth System Model (CESM) with active atmospheric chemistry, climate and land surface components. Previous overestimation of surface ozone in eastern US, Canada and Europe is shown to be reduced by >8 ppb, reflecting improved model-observation comparison. Simulated surface ozone is lower by 3.7 ppb on average globally. Such reductions (and improvements) in simulated ozone are caused mainly by lower isoprene emission arising from reduced leaf area index in response to chronic ozone exposure. Effects via transpiration are also potentially significant but require better characterization. Such findings suggest that ozone-vegetation interaction may substantially alter future ozone simulations, especially under changing climate and ambient CO2 levels, which would further modulate ozone-vegetation interactions. Inclusion of such interactions in Earth system models is thus necessary to give more realistic estimation and prediction of surface ozone. This is crucial for better policy formulation regarding air quality, land use and climate change mitigation. Reference list: Lombardozzi, D., et al. "The Influence of Chronic Ozone Exposure on Global Carbon and Water Cycles." Journal of Climate 28.1 (2015): 292-305.

Direct and semi-direct aerosol radiative effect on the Mediterranean climate variability using a coupled regional climate system model

NASA Astrophysics Data System (ADS)

Nabat, Pierre; Somot, Samuel; Mallet, Marc; Sevault, Florence; Chiacchio, Marc; Wild, Martin

2015-02-01

A fully coupled regional climate system model (CNRM-RCSM4) has been used over the Mediterranean region to investigate the direct and semi-direct effects of aerosols, but also their role in the radiation-atmosphere-ocean interactions through multi-annual ensemble simulations (2003-2009) with and without aerosols and ocean-atmosphere coupling. Aerosols have been taken into account in CNRM-RCSM4 through realistic interannual monthly AOD climatologies. An evaluation of the model has been achieved, against various observations for meteorological parameters, and has shown the ability of CNRM-RCSM4 to reproduce the main patterns of the Mediterranean climate despite some biases in sea surface temperature (SST), radiation and cloud cover. The results concerning the aerosol radiative effects show a negative surface forcing on average because of the absorption and scattering of the incident radiation. The SW surface direct effect is on average -20.9 Wm-2 over the Mediterranean Sea, -14.7 Wm-2 over Europe and -19.7 Wm-2 over northern Africa. The LW surface direct effect is weaker as only dust aerosols contribute (+4.8 Wm-2 over northern Africa). This direct effect is partly counterbalanced by a positive semi-direct radiative effect over the Mediterranean Sea (+5.7 Wm-2 on average) and Europe (+5.0 Wm-2) due to changes in cloud cover and atmospheric circulation. The total aerosol effect is consequently negative at the surface and responsible for a decrease in land (on average -0.4 °C over Europe, and -0.5 °C over northern Africa) and sea surface temperature (on average -0.5 °C for the Mediterranean SST). In addition, the latent heat loss is shown to be weaker (-11.0 Wm-2) in the presence of aerosols, resulting in a decrease in specific humidity in the lower troposphere, and a reduction in cloud cover and precipitation. Simulations also indicate that dust aerosols warm the troposphere by absorbing solar radiation, and prevent radiation from reaching the surface, thus stabilizing the troposphere. The comparison with the model response in atmosphere-only simulations shows that these feedbacks are attenuated if SST cannot be modified by aerosols, highlighting the importance of using coupled regional models over the Mediterranean. Oceanic convection is also strengthened by aerosols, which tends to reinforce the Mediterranean thermohaline circulation. In parallel, two case studies are presented to illustrate positive feedbacks between dust aerosols and regional climate. First, the eastern Mediterranean was subject to high dust aerosol loads in June 2007 which reduce land and sea surface temperature, as well as air-sea humidity fluxes. Because of northern wind over the eastern Mediterranean, drier and cooler air has been consequently advected from the sea to the African continent, reinforcing the direct dust effect over land. On the contrary, during the western European heat wave in June 2006, dust aerosols have contributed to reinforcing an important ridge responsible for dry and warm air advection over western Europe, and thus to increasing lower troposphere (+0.8 °C) and surface temperature (+0.5 °C), namely about 15 % of this heat wave.

Air-borne and tissue-borne sensitivities of bioacoustic sensors used on the skin surface.

PubMed

Zañartu, Matías; Ho, Julio C; Kraman, Steve S; Pasterkamp, Hans; Huber, Jessica E; Wodicka, George R

2009-02-01

Measurements of body sounds on the skin surface have been widely used in the medical field and continue to be a topic of current research, ranging from the diagnosis of respiratory and cardiovascular diseases to the monitoring of voice dosimetry. These measurements are typically made using light-weight accelerometers and/or air-coupled microphones attached to the skin. Although normally neglected, air-borne sounds generated by the subject or other sources of background noise can easily corrupt such recordings, which is particularly critical in the recording of voiced sounds on the skin surface. In this study, the sensitivity of commonly used bioacoustic sensors to air-borne sounds was evaluated and compared with their sensitivity to tissue-borne body sounds. To delineate the sensitivity to each pathway, the sensors were first tested in vitro and then on human subjects. The results indicated that, in general, the air-borne sensitivity is sufficiently high to significantly corrupt body sound signals. In addition, the air-borne and tissue-borne sensitivities can be used to discriminate between these components. Although the study is focused on the evaluation of voiced sounds on the skin surface, an extension of the proposed methods to other bioacoustic applications is discussed.

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.

NASA AIRS Examines Hurricane Matthew Cloud Top Temperatures

NASA Image and Video Library

2016-10-07

At 11:29 p.m. PDT on Oct. 6 (2:29 a.m. EDT on Oct. 7), NASA's Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite produced this false-color infrared image of Matthew as the storm moved up Florida's central coast. The image shows the temperature of Matthew's cloud tops or the surface of Earth in cloud-free regions, with the most intense thunderstorms shown in purples and blues. http://photojournal.jpl.nasa.gov/catalog/PIA21097

AirSWOT Measurements of Water Surface Elevations and Hydraulic Gradients over the Yukon Flats, Alaska

NASA Astrophysics Data System (ADS)

Pitcher, L. H.; Pavelsky, T.; Smith, L. C.; Moller, D.; Altenau, E. H.; Lion, C.; Bertram, M.; Cooley, S. W.

2017-12-01

AirSWOT is an airborne, Ka-band synthetic aperture radar interferometer (InSAR) intended to quantify surface water fluxes by mapping water surface elevations (WSE). AirSWOT will also serve as a calibration/validation tool for the Surface Water and Ocean Topography (SWOT) satellite mission (scheduled for launch in 2021). The hydrology objectives for AirSWOT and SWOT are to measure WSE with accuracies sufficient to estimate hydrologic fluxes in lakes, wetlands and rivers. However, current understanding of the performance of these related though not identical instruments when applied to complex river-lake-wetland fluvial environments remains predominantly theoretical. We present AirSWOT data acquired 15-June-2015 over the Yukon Flats, Alaska, USA, together with in situ field surveys, to assess the accuracy of AirSWOT WSE measurements in lakes and rivers. We use these data to demonstrate that AirSWOT can be used to estimate large-scale hydraulic gradients across wetland complexes. Finally, we present key lessons learned from this AirSWOT analysis for consideration in future campaigns, including: maximizing swath overlap for spatial averaging to minimize uncertainty as well as orienting flight paths parallel to river flow directions to reduce along track aircraft drift for neighboring flight paths. We conclude that spatially dense AirSWOT measurements of river and lake WSEs can improve geospatial understanding of surface water hydrology and fluvial processes.

Method of energy load management using PCM for heating and cooling of buildings

DOEpatents

Stovall, T.K.; Tomlinson, J.J.

1996-03-26

A method is described for energy load management for the heating and cooling of a building. The method involves utilizing a wallboard as a portion of the building, the wallboard containing about 5 to about 30 wt.% phase change material such that melting of the phase change material occurs during a rise in temperature within the building to remove heat from the air, and a solidification of the phase change material occurs during a lowering of the temperature to dispense heat into the air. At the beginning of either of these cooling or heating cycles, the phase change material is preferably ``fully charged``. In preferred installations one type of wallboard is used on the interior surfaces of exterior walls, and another type as the surface on interior walls. The particular PCM is chosen for the desired wall and room temperature of these locations. In addition, load management is achieved by using PCM-containing wallboards that form cavities of the building such that the cavities can be used for the air handling duct and plenum system of the building. Enhanced load management is achieved by using a thermostat with reduced dead band of about the upper half of a normal dead band of over three degrees. In some applications, air circulation at a rate greater than normal convection provides additional comfort. 7 figs.

Method of energy load management using PCM for heating and cooling of buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stovall, T.K.; Tomlinson, J.J.

1996-03-26

A method is described for energy load management for the heating and cooling of a building. The method involves utilizing a wallboard as a portion of the building, the wallboard containing about 5 to about 30 wt.% phase change material such that melting of the phase change material occurs during a rise in temperature within the building to remove heat from the air, and a solidification of the phase change material occurs during a lowering of the temperature to dispense heat into the air. At the beginning of either of these cooling or heating cycles, the phase change material ismore » preferably ``fully charged``. In preferred installations one type of wallboard is used on the interior surfaces of exterior walls, and another type as the surface on interior walls. The particular PCM is chosen for the desired wall and room temperature of these locations. In addition, load management is achieved by using PCM-containing wallboards that form cavities of the building such that the cavities can be used for the air handling duct and plenum system of the building. Enhanced load management is achieved by using a thermostat with reduced dead band of about the upper half of a normal dead band of over three degrees. In some applications, air circulation at a rate greater than normal convection provides additional comfort. 7 figs.« less

New Technology-Large-Area Three- Dimensional Surface Profiling Using Only Focused Air-Coupled Ultrasound-Given 1999 R&D 100 Award

NASA Technical Reports Server (NTRS)

Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.

2000-01-01

Surface topography, which significantly affects the performance of many industrial components, is normally measured with diamond-tip profilometry over small areas or with optical scattering methods over larger areas. To develop air-coupled surface profilometry, the NASA Glenn Research Center at Lewis Field initiated a Space Act Agreement with Sonix, Inc., through two Glenn programs, the Advanced High Temperature Engine Materials Program (HITEMP) and COMMTECH. The work resulted in quantitative surface topography profiles obtained using only high-frequency, focused ultrasonic pulses in air. The method is nondestructive, noninvasive, and noncontact, and it does not require light-reflective surfaces. Air surface profiling may be desirable when diamond-tip or laserbased methods are impractical, such as over large areas, when a significant depth range is required, or for curved surfaces. When the configuration is optimized, the method is reasonably rapid and all the quantitative analysis facilities are online, including two- and three-dimensional visualization, extreme value filtering (for faulty data), and leveling.

Solutions Network Formulation Report. NASA's Potential Contributions for Using Solar Ultraviolet Radiation in Conjunction with Photocatalysis for Urban Air Pollution Mitigation and Increasing Air Quality

NASA Technical Reports Server (NTRS)

Underwood, Lauren; Ryan, Robert E.

2007-01-01

This Candidate Solution is based on using NASA Earth science research on atmospheric ozone and aerosols data as a means to predict and evaluate the effectiveness of photocatalytically created surfaces (building materials like glass, tile and cement) for air pollution mitigation purposes. When these surfaces are exposed to near UV light, organic molecules, like air pollutants and smog precursors, will degrade into environmentally friendly compounds. U.S. EPA (Environmental Protection Agency) is responsible for forecasting daily air quality by using the Air Quality Index (AQI) that is provided by AIRNow. EPA is partnered with AIRNow and is responsible for calculating the AQI for five major air pollutants that are regulated by the Clean Air Act. In this Solution, UV irradiance data acquired from the satellite mission Aura and the OMI Surface UV algorithm will be used to help understand both the efficacy and efficiency of the photocatalytic decomposition process these surfaces facilitate, and their ability to reduce air pollutants. Prediction models that estimate photocatalytic function do not exist. NASA UV irradiance data will enable this capability, so that air quality agencies that are run by state and local officials can develop and implement programs that utilize photocatalysis for urban air pollution control and, enable them to make effective decisions about air pollution protection programs.

Strong Dependence of U.S. Summertime Air Quality on the Decadal Variability of Atlantic Sea Surface Temperatures

NASA Astrophysics Data System (ADS)

Shen, Lu; Mickley, Loretta J.; Leibensperger, Eric M.; Li, Mingwei

2017-12-01

We find that summertime air quality in the eastern U.S. displays strong dependence on North Atlantic sea surface temperatures, resulting from large-scale ocean-atmosphere interactions. Using observations, reanalysis data sets, and climate model simulations, we further identify a multidecadal variability in surface air quality driven by the Atlantic Multidecadal Oscillation (AMO). In one-half cycle ( 35 years) of the AMO from cold to warm phase, summertime maximum daily 8 h ozone concentrations increase by 1-4 ppbv and PM2.5 concentrations increase by 0.3-1.0 μg m-3 over much of the east. These air quality changes are related to warmer, drier, and more stagnant weather in the AMO warm phase, together with anomalous circulation patterns at the surface and aloft. If the AMO shifts to the cold phase in future years, it could partly offset the climate penalty on U.S. air quality brought by global warming, an effect which should be considered in long-term air quality planning.

Milk whey proteins and xanthan gum interactions in solution and at the air-water interface: a rheokinetic study.

PubMed

Perez, Adrián A; Sánchez, Cecilio Carrera; Patino, Juan M Rodríguez; Rubiolo, Amelia C; Santiago, Liliana G

2010-11-01

In this contribution, we present experimental information about the effect of xanthan gum (XG) on the adsorption behaviour of two milk whey protein samples (MWP), beta-lactoglobulin (beta-LG) and whey protein concentrate (WPC), at the air-water interface. The MWP concentration studied corresponded to the protein bulk concentration which is able to saturate the air-water interface (1.0 wt%). Temperature, pH and ionic strength of aqueous systems were kept constant at 20 degrees C, pH 7 and 0.05 M, respectively, while the XG bulk concentration varied in the range 0.00-0.25 wt%. Biopolymer interactions in solution were analyzed by extrinsic fluorescence spectroscopy using 1-anilino-8-naphtalene sulphonic acid (ANS) as a protein fluorescence probe. Interfacial biopolymer interactions were evaluated by dynamic tensiometry and surface dilatational rheology. Adsorption behaviour was discussed from a rheokinetic point of view in terms of molecular diffusion, penetration and conformational rearrangement of adsorbed protein residues at the air-water interface. Differences in the interaction magnitude, both in solution and at the interface vicinity, and in the adsorption rheokinetic parameters were observed in MWP/XG mixed systems depending on the protein type (beta-LG or WPC) and biopolymer relative concentration. beta-LG adsorption in XG presence could be promoted by mechanisms based on biopolymer segregative interactions and thermodynamic incompatibility in the interface vicinity, resulting in better surface and viscoelastic properties. The same mechanism could be responsible of WPC interfacial adsorption in the presence of XG. The interfacial functionality of WPC was improved by the synergistic interactions with XG, although WPC chemical complexity might complicate the elucidation of molecular events that govern adsorption dynamics of WPC/XG mixed systems at the air-water interface. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Effect of heat treatment on surface hydrophilicity-retaining ability of titanium dioxide nanotubes

NASA Astrophysics Data System (ADS)

Sun, Yu; Sun, Shupei; Liao, Xiaoming; Wen, Jiang; Yin, Guangfu; Pu, Ximing; Yao, Yadong; Huang, Zhongbing

2018-05-01

The aim of this study is to investigate the effect of different annealing temperature and atmosphere on the surface wettability retaining properties of titania nanotubes (TNs) fabricated by anodization. The TNs morphology, crystal phase composition and surface elemental composition and water contact angle (WCA) were investigated by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and contact angle instrument, respectively. After the samples annealed at 200 °C, 450 °C, 850 °C have been stored in air for 28 days, the WCAs increase to 31.7°, 21.1° and 110.5°, respectively. The results indicate that crystal phase composition of TNs plays an important role in surface wettability. Compared with the WCA (21.1°) of the samples annealed in air after 28 days, the WCA of samples annealed in oxygen-deficient atmosphere is lower, suggesting the contribution of oxygen vacancy in the enhanced hydrophilicity-retaining ability. Our study demonstrates that the surface hydrophilicity-retaining ability of TNs is related to the ordered nanotubular structure, crystal structure, the amount of surface hydroxyl group and oxygen vacancy defects.

KSC-97pc678

NASA Image and Video Library

1997-04-21

Workers offload the shipping container with the Cassini orbiter from what looks like a giant shark mouth, but is really an Air Force C-17 air cargo plane which just landed at KSC’s Shuttle Landing Facility from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn’s largest moon, Titan. The orbiter was designed and assembled at NASA’s Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004

KSC-97pc680

NASA Image and Video Library

1997-04-21

Workers prepare to move the shipping container with the Cassini orbiter inside the Payload Hazardous Servicing Facility (PHSF) for prelaunch processing, testing and integration. The orbiter arrived at KSC’s Shuttle Landing Facility in a U.S. Air Force C-17 air cargo plane from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn’s largest moon, Titan. The orbiter was designed and assembled at NASA’s Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004

KSC-97pc682

NASA Image and Video Library

1997-04-21

Workers prepare to move the shipping container with the Cassini orbiter inside the Payload Hazardous Servicing Facility (PHSF) for prelaunch processing, testing and integration. The orbiter arrived at KSC’s Shuttle Landing Facility in a U.S. Air Force C-17 air cargo plane from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn’s largest moon, Titan. The orbiter was designed and assembled at NASA’s Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004

KSC-97pc681

NASA Image and Video Library

1997-04-21

Workers prepare to move the shipping container with the Cassini orbiter inside the Payload Hazardous Servicing Facility (PHSF) for prelaunch processing, testing and integration. The orbiter arrived at KSC’s Shuttle Landing Facility in a U.S. Air Force C-17 air cargo plane from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn’s largest moon, Titan. The orbiter was designed and assembled at NASA’s Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004

Cassini orbiter arrives at SLF

NASA Technical Reports Server (NTRS)

1997-01-01

Workers offload the shipping container with the Cassini orbiter from what looks like a giant shark mouth, but is really an Air Force C-17 air cargo plane which just landed at KSC's Shuttle Landing Facility from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn's largest moon, Titan. The orbiter was designed and assembled at NASA's Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004.

Cassini orbiter arrives at SLF

NASA Technical Reports Server (NTRS)

1997-01-01

Workers prepare to tow away the large container with the Cassini orbiter from KSC's Shuttle Landing Facility. The orbiter just arrived on the U.S. Air Force C-17 air cargo plane, shown here, from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn's largest moon, Titan. The orbiter was designed and assembled at NASA's Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004.

40 CFR 60.397 - Modifications.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Modifications. 60.397 Section 60.397 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Automobile and Light Duty Truck Surface...

7 CFR 1466.20 - Application for contracts and selecting applications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... concerning soil, water and air quality; wildlife habitat; and ground and surface water conservation; (vi... include water conservation or irrigation efficiency practices, the State Conservationist will give... conservation practices; (ii) The magnitude of the expected environmental benefits resulting from the...

7 CFR 1466.20 - Application for contracts and selecting applications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... concerning soil, water and air quality; wildlife habitat; and ground and surface water conservation; (vi... include water conservation or irrigation efficiency practices, the State Conservationist will give... conservation practices; (ii) The magnitude of the expected environmental benefits resulting from the...

7 CFR 1466.20 - Application for contracts and selecting applications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... concerning soil, water and air quality; wildlife habitat; and ground and surface water conservation; (vi... include water conservation or irrigation efficiency practices, the State Conservationist will give... conservation practices; (ii) The magnitude of the expected environmental benefits resulting from the...

40 CFR 60.397 - Modifications.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Modifications. 60.397 Section 60.397 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Automobile and Light Duty Truck Surface...

40 CFR 60.397 - Modifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Modifications. 60.397 Section 60.397 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Automobile and Light Duty Truck Surface...

Test method development to evaluate hot, humid air decontamination of materials contaminated with Bacillus anthracis ∆Sterne and B. thuringiensis Al Hakam spores.

PubMed

Buhr, T L; Young, A A; Minter, Z A; Wells, C M; McPherson, D C; Hooban, C L; Johnson, C A; Prokop, E J; Crigler, J R

2012-11-01

To develop test methods and evaluate the survival of Bacillus anthracis ∆Sterne and Bacillus thuringiensis Al Hakam spores after exposure to hot, humid air. Spores (>7 logs) of both strains were dried on six different test materials. Response surface methodology was employed to identify the limits of spore survival at optimal test combinations of temperature (60, 68, 77°C), relative humidity (60, 75, 90%) and time (1, 4, 7 days). No spores survived the harshest test run (77°C, 90% r.h., 7 days), while > 6·5 logs of spores survived the mildest test run (60°C, 60% r.h., 1 day). Spores of both strains inoculated on nylon webbing and polypropylene had greater survival rates at 68°C, 75% r.h., 4 days than spores on other materials. Electron microscopy showed no obvious physical damage to spores using hot, humid air, which contrasted with pH-adjusted bleach decontamination. Test methods were developed to show that hot, humid air effectively inactivates B. anthracis ∆Sterne and B. thuringiensis Al Hakam spores with similar kinetics. Hot, humid air is a potential alternative to conventional chemical decontamination. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Changes in duration of dry and wet spells associated with air temperatures in Russia

NASA Astrophysics Data System (ADS)

Ye, Hengchun

2018-03-01

This study uses daily precipitation records from 517 Russian stations (1966-2010) to examine the relationships between continuous dry and wet day duration and surface air temperature for all four seasons. The study found that both mean and extreme durations of dry periods increase with air temperature at about 7.0% (0.24 day/°C) and 7.7% (0.86 day/°C) respectively, while those of wet periods decrease at about 1.3% (-0.02 day/°C) and 2.2% (-0.10 day/°C) respectively averaged over the entire study region during summer. An increase in the duration of dry periods with higher air temperature is also found in other seasons at locations with a mean seasonal air temperature of about -5 °C or higher. Opposite relationships of shorter durations of dry periods and longer wet periods associated with higher air temperature are observed over the northern part of the study region in winter. The changes in durations of both dry and wet periods have significant correlations with the changes in total dry and wet days but are about 2.5 times higher for dry periods and 0.5 times lower for wet periods. The study also found that locations with longer durations of dry periods experience faster rates of increase in air temperature, suggesting the likelihood of exacerbating drought severity in drier and/or warmer locations for all seasons.

KSC01pp0637

NASA Image and Video Library

2001-03-27

Workers on Launch Pad 17-A, Cape Canaveral Air Force Station, get ready to move the Mars Odyssey spacecraft into the clean room at the top of the gantry. There it will be mated encased by the fairing of the Delta II rocket already in place. The spacecraft will map the Martian surface in search of geological features that could indicate the presence of water, now or in the past, and may contribute significantly toward understanding what will be necessary for a more sophisticated exploration of Mars. Launch is scheduled for 11:02 a.m. EDT April 7

Modification of structure and pattern of lipid monolayer on water and solid surfaces in presence of globular protein

NASA Astrophysics Data System (ADS)

Sah, Bijay Kumar; Kundu, Sarathi

2017-05-01

Langmuir monolayers of phospholipids at the air-water interface are well-established model systems for mimicking biological membranes and hence are useful for studying lipid-protein interactions. In the present work, phases and phase transformations occurring in the lipid (DMPA) monolayer in the presence of globular protein (BSA) at neutral subphase pH (≈7.0) are highlighted and the corresponding in-plane pattern and morphology are explored from the surface pressure (π) - specific molecular area (A) isotherm, Brewster angle microscopy (BAM) and atomic force microscopy (AFM) both at air-water and air-solid interfaces. Films of pure lipid and lipid-protein complexes are deposited on solid surfaces by Langmuir-Blodgett method. Due to the presence of BSA molecules, phases and domain pattern changes in comparison with that of the pure DMPA. Moreover, accumulations of globular proteins in between lipid domains are also visible through BAM. AFM shows that the mixed film has relatively bigger globular-like morphology in comparison with that of pure DMPA domains. Combination of electrostatic and hydrophobic interactions between protein and lipid are responsible for such modifications.

The diversity and distribution of fungi on residential surfaces.

PubMed

Adams, Rachel I; Miletto, Marzia; Taylor, John W; Bruns, Thomas D

2013-01-01

The predominant hypothesis regarding the composition of microbial assemblages in indoor environments is that fungal assemblages are structured by outdoor air with a moderate contribution by surface growth, whereas indoor bacterial assemblages represent a mixture of bacteria entered from outdoor air, shed by building inhabitants, and grown on surfaces. To test the fungal aspect of this hypothesis, we sampled fungi from three surface types likely to support growth and therefore possible contributors of fungi to indoor air: drains in kitchens and bathrooms, sills beneath condensation-prone windows, and skin of human inhabitants. Sampling was done in replicated units of a university-housing complex without reported mold problems, and sequences were analyzed using both QIIME and the new UPARSE approach to OTU-binning, to the same result. Surfaces demonstrated a mycological profile similar to that of outdoor air from the same locality, and assemblages clustered by surface type. "Weedy" genera typical of indoor air, such as Cladosporium and Cryptococcus, were abundant on sills, as were a diverse set of fungi of likely outdoor origin. Drains supported more depauperate assemblages than the other surfaces and contained thermotolerant genera such as Exophiala, Candida, and Fusarium. Most surprising was the composition detected on residents' foreheads. In addition to harboring Malassezia, a known human commensal, skin also possessed a surprising richness of non-resident fungi, including plant pathogens such as ergot (Claviceps purperea). Overall, fungal richness across indoor surfaces was high, but based on known autecologies, most of these fungi were unlikely to be growing on surfaces. We conclude that while some endogenous fungal growth on typical household surfaces does occur, particularly on drains and skin, all residential surfaces appear - to varying degrees - to be passive collectors of airborne fungi of putative outdoor origin, a view of the origins of the indoor microbiome quite different from bacteria.

Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

PubMed Central

Stapleton, Helen L.

2016-01-01

ABSTRACT Spores of an acrystalliferous derivative of Bacillus thuringiensis subsp. kurstaki, termed Btcry−, are morphologically, aerodynamically, and structurally indistinguishable from Bacillus anthracis spores. Btcry− spores were dispersed in a large, open-ended barn together with spores of Bacillus atrophaeus subsp. globigii, a historically used surrogate for Bacillus anthracis. Spore suspensions (2 × 1012 CFU each of B. atrophaeus subsp. globigii and Btcry−) were aerosolized in each of five spray events using a backpack misting device incorporating an air blower; a wind of 4.9 to 7.6 m s−1 was also flowing through the barn in the same direction. Filter air samplers were situated throughout the barn to assess the aerosol density of the spores during each release. Trays filled with a surfactant in aqueous buffer were placed on the floor near the filter samplers to assess spore deposition. Spores were also recovered from arrays of solid surfaces (concrete, aluminum, and plywood) that had been laid on the floor and set up as a wall at the end of the barn. B. atrophaeus subsp. globigii spores were found to remain airborne for significantly longer periods, and to be deposited on horizontal surfaces at lower densities, than Btcry− spores, particularly near the spray source. There was a 6-fold-higher deposition of Btcry− spores than of B. atrophaeus subsp. globigii spores on vertical surfaces relative to the surrounding airborne density. This work is relevant for selecting the best B. anthracis surrogate for the prediction of human exposure, hazard assessment, and hazard management following a malicious release of B. anthracis. IMPORTANCE There is concern that pathogenic bacteria could be maliciously disseminated in the air to cause human infection and disruption of normal life. The threat from spore-forming organisms, such as the causative agent of anthrax, is particularly serious. In order to assess the extent of this risk, it is important to have a surrogate organism that can be used to replicate the dispersal characteristics of the threat agent accurately. This work compares the aerosol dispersal and deposition behaviors of the surrogates Btcry− and B. atrophaeus subsp. globigii. Btcry− spores remained in the air for a shorter time, and were markedly more likely to adhere to vertical surfaces, than B. atrophaeus subsp. globigii spores. PMID:27613681

Assessing the impacts of seasonal and vertical atmospheric conditions on air quality over the Pearl River Delta region

NASA Astrophysics Data System (ADS)

Tong, Cheuk Hei Marcus; Yim, Steve Hung Lam; Rothenberg, Daniel; Wang, Chien; Lin, Chuan-Yao; Chen, Yongqin David; Lau, Ngar Cheung

2018-05-01

Air pollution is an increasingly concerning problem in many metropolitan areas due to its adverse public health and environmental impacts. Vertical atmospheric conditions have strong effects on vertical mixing of air pollutants, which directly affects surface air quality. The characteristics and magnitude of how vertical atmospheric conditions affect surface air quality, which are critical to future air quality projections, have not yet been fully understood. This study aims to enhance understanding of the annual and seasonal sensitivities of air pollution to both surface and vertical atmospheric conditions. Based on both surface and vertical meteorological characteristics provided by 1994-2003 monthly dynamic downscaling data from the Weather and Research Forecast Model, we develop generalized linear models (GLMs) to study the relationships between surface air pollutants (ozone, respirable suspended particulates, and sulfur dioxide) and atmospheric conditions in the Pearl River Delta (PRD) region. Applying Principal Component Regression (PCR) to address multi-collinearity, we study the contributions of various meteorological variables to pollutants' concentration levels based on the loading and model coefficient of major principal components. Our results show that relatively high pollutant concentration occurs under relatively low mid-level troposphere temperature gradients, low relative humidity, weak southerly wind (or strong northerly wind) and weak westerly wind (or strong easterly wind). Moreover, the correlations vary among pollutant species, seasons, and meteorological variables at various altitudes. In general, pollutant sensitivity to meteorological variables is found to be greater in winter than in other seasons, and the sensitivity of ozone to meteorology differs from that of the other two pollutants. Applying our GLMs to anomalous air pollution episodes, we find that meteorological variables up to mid troposphere (∼700 mb) play an important role in influencing surface air quality, pinpointing the significant and unique associations between meteorological variables at higher altitudes and surface air quality.

The role of size in synchronous air breathing of Hoplosternum littorale.

PubMed

Sloman, Katherine A; Sloman, Richard D; De Boeck, Gudrun; Scott, Graham R; Iftikar, Fathima I; Wood, Chris M; Almeida-Val, Vera M F; Val, Adalberto L

2009-01-01

Synchronized air breathing may have evolved as a way of minimizing the predation risk known to be associated with air breathing in fish. Little is known about how the size of individuals affects synchronized air breathing and whether some individuals are required to surface earlier than necessary in support of conspecifics, while others delay air intake. Here, the air-breathing behavior of Hoplosternum littorale held in groups or in isolation was investigated in relation to body mass, oxygen tensions, and a variety of other physiological parameters (plasma lactate, hepatic glycogen, hematocrit, hemoglobin, and size of heart, branchial basket, liver, and air-breathing organ [ABO]). A mass-specific relationship with oxygen tension of first surfacing was seen when fish were held in isolation; smaller individuals surfaced at higher oxygen tensions. However, this relationship was lost when the same individuals were held in social groups of four, where synchronous air breathing was observed. In isolation, 62% of fish first surfaced at an oxygen tension lower than the calculated P(crit) (8.13 kPa), but in the group environment this was reduced to 38% of individuals. Higher oxygen tensions at first surfacing in the group environment were related to higher levels of activity rather than any of the physiological parameters measured. In fish held in isolation but denied access to the water surface for 12 h before behavioral testing, there was no mass-specific relationship with oxygen tension at first surfacing. Larger individuals with a greater capacity to store air in their ABOs may, therefore, remain in hypoxic waters for longer periods than smaller individuals when held in isolation unless prior access to the air is prevented. This study highlights how social interaction can affect air-breathing behaviors and the importance of considering both behavioral and physiological responses of fish to hypoxia to understand the survival mechanisms they employ.

Air-spun PLA nanofibers modified with reductively sheddable hydrophilic surfaces for vascular tissue engineering: synthesis and surface modification.

PubMed

Ko, Na Re; Sabbatier, Gad; Cunningham, Alexander; Laroche, Gaétan; Oh, Jung Kwon

2014-02-01

Polylactide (PLA) is a class of promising biomaterials that hold great promise for various biological and biomedical applications, particularly in the field of vascular tissue engineering where it can be used as a fibrous mesh to coat the inside of vascular prostheses. However, its hydrophobic surface providing nonspecific interactions and its limited ability to further modifications are challenges that need to be overcome. Here, the development of new air-spun PLA nanofibers modified with hydrophilic surfaces exhibiting reduction response is reported. Surface-initiated atom transfer radical polymerization allows for grafting pendant oligo(ethylene oxide)-containing polymethacrylate (POEOMA) from PLA air-spun fibers labeled with disulfide linkages. The resulting PLA-ss-POEOMA fibers exhibit enhanced thermal stability and improved surface properties, as well as thiol-responsive shedding of hydrophilic POEOMA by the cleavage of its disulfide linkages in response to reductive reactions, thus tuning the surface properties. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low clouds suppress Arctic air formation and amplify high-latitude continental winter warming.

PubMed

Cronin, Timothy W; Tziperman, Eli

2015-09-15

High-latitude continents have warmed much more rapidly in recent decades than the rest of the globe, especially in winter, and the maintenance of warm, frost-free conditions in continental interiors in winter has been a long-standing problem of past equable climates. We use an idealized single-column atmospheric model across a range of conditions to study the polar night process of air mass transformation from high-latitude maritime air, with a prescribed initial temperature profile, to much colder high-latitude continental air. We find that a low-cloud feedback--consisting of a robust increase in the duration of optically thick liquid clouds with warming of the initial state--slows radiative cooling of the surface and amplifies continental warming. This low-cloud feedback increases the continental surface air temperature by roughly two degrees for each degree increase of the initial maritime surface air temperature, effectively suppressing Arctic air formation. The time it takes for the surface air temperature to drop below freezing increases nonlinearly to ∼ 10 d for initial maritime surface air temperatures of 20 °C. These results, supplemented by an analysis of Coupled Model Intercomparison Project phase 5 climate model runs that shows large increases in cloud water path and surface cloud longwave forcing in warmer climates, suggest that the "lapse rate feedback" in simulations of anthropogenic climate change may be related to the influence of low clouds on the stratification of the lower troposphere. The results also indicate that optically thick stratus cloud decks could help to maintain frost-free winter continental interiors in equable climates.

Low clouds suppress Arctic air formation and amplify high-latitude continental winter warming

PubMed Central

Cronin, Timothy W.; Tziperman, Eli

2015-01-01

High-latitude continents have warmed much more rapidly in recent decades than the rest of the globe, especially in winter, and the maintenance of warm, frost-free conditions in continental interiors in winter has been a long-standing problem of past equable climates. We use an idealized single-column atmospheric model across a range of conditions to study the polar night process of air mass transformation from high-latitude maritime air, with a prescribed initial temperature profile, to much colder high-latitude continental air. We find that a low-cloud feedback—consisting of a robust increase in the duration of optically thick liquid clouds with warming of the initial state—slows radiative cooling of the surface and amplifies continental warming. This low-cloud feedback increases the continental surface air temperature by roughly two degrees for each degree increase of the initial maritime surface air temperature, effectively suppressing Arctic air formation. The time it takes for the surface air temperature to drop below freezing increases nonlinearly to ∼10 d for initial maritime surface air temperatures of 20 °C. These results, supplemented by an analysis of Coupled Model Intercomparison Project phase 5 climate model runs that shows large increases in cloud water path and surface cloud longwave forcing in warmer climates, suggest that the “lapse rate feedback” in simulations of anthropogenic climate change may be related to the influence of low clouds on the stratification of the lower troposphere. The results also indicate that optically thick stratus cloud decks could help to maintain frost-free winter continental interiors in equable climates. PMID:26324919

Comparison of Near-Surface Air Temperatures and MODIS Ice-Surface Temperatures at Summit, Greenland (2008-2013)

NASA Technical Reports Server (NTRS)

Shuman, Christopher A.; Hall, Dorothy K.; DiGirolamo, Nicolo E.; Mefford, Thomas K.; Schnaubelt, Michael J.

2014-01-01

We have investigated the stability of the MODerate resolution Imaging Spectroradiometer (MODIS) infrared-derived ice surface temperature (IST) data from Terra for use as a climate quality data record. The availability of climate quality air temperature data (TA) from a NOAA Global Monitoring Division observatory at Greenlands Summit station has enabled this high temporal resolution study of MODIS ISTs. During a 5 year period (July 2008 to August 2013), more than 2500 IST values were compared with 3-minute average TA values derived from the 1-minute data from NOAAs primary 2 m air temperature sensor. These data enabled an expected small offset between air and surface temperatures at this the ice sheet location to be investigated over multiple annual cycles.

Effect of air velocity and direction for indirect evaporative cooling in tropical area

NASA Astrophysics Data System (ADS)

Ayodha Ajiwiguna, Tri; Nugraha Rismi, Fadhlin; Ramdlan Kirom, Mukhammad

2017-06-01

In this research, experimental study of heat absorption rate caused by indirect evaporative cooling is performed by varying the velocity and direction of air. The ambient is at average temperature and relative humidity of 28.7 °C and 78% respectively. The experiment is conducted by attaching wet medium on the top of material reference plate with the dimension of 14 x 8 cm with 5 mm thickness. To get evaporative cooling effect, the air flow is directed to the wet medium with velocity from 1.6 m/s to 3.4 m/s with the increment of 0.2 m/s. The direction of air is set 0° (parallel), 45° (inclined), and 90° (perpendicular) to the wet medium surface. While the experiment is being performed, the air temperature, top and bottom of plate temperature are measured simultaneously after steady state condition is established. Based on the measurement result, heat absorption is calculated by analysing the heat conduction on the material reference. The result shows that the heat absorption rate is increased by higher velocity. Perpendicular direction of air flow results the highest cooling capacity compared with other direction. The maximum heat absorption rate is achieved at 13.9 Watt with 3.4 m/s velocity and perpendicular direction of air.

The effect of differing support surfaces on the efficacy of chest compressions using a resuscitation manikin model.

PubMed

Tweed, M; Tweed, C; Perkins, G D

2001-11-01

External chest compression (ECC) efficacy is influenced by factors including the surface supporting the patient. Air-filled support surfaces are deflated for cardiopulmonary resuscitation, with little evidence to substantiate this. We investigated the effect that differing support surfaces had on ECC efficacy using a CPR manikin model. Four participants carried out four cycles of ECC with an assistant ventilating. The subjects were blinded to the seven support surfaces and the order was randomised. For each participant/surface combination, ECC variables and the participants' perceptions were measured. Participants produced effective ECC with the manikin on the floor (mean proportion correct, 94.5%; mean depth, 42.5 mm). Compared with the floor: the proportion of correct ECC was less for the overlay inflated (P<0.05); the depth of ECC was less effective (30-37 mm) for the overlay inflated/deflated and low-air-loss inflated and foam mattresses (P<0.05). The foam mattress, overlay inflated/deflated, and low-air-loss inflated were perceived as being less stable and as having reduced ECC efficacy compared with the floor. There was no difference or agreement, regarding subjects' perceptions or ECC variables, between the support surfaces or between inflated/deflated air-filled support surfaces. The efficacy of ECC is affected by the support surfaces. There seems little evidence to substantiate deflating all air-filled support surfaces for CPR.

Levels of organic compounds in interiors (school, home, university and hospital) of Ouargla city, Algeria

NASA Astrophysics Data System (ADS)

Boudehane, A.; Lounas, A.; Moussaoui, Y.; Balducci, C.; Cecinato, A.

2016-11-01

Indoor environments are affected by a number of organic contaminants, whose concentrations can exceed by orders of magnitude those found outdoors in external air. At this regard, polycyclic aromatic hydrocarbons (PAHs) deserve a special concern. PAHs occur in the air both in the gaseous and particulate forms; they are associated to fine aerosols and soil dust, and deposit on surfaces. Nonetheless, scarce information exists about the PAH pollution of indoor locations in Northern Africa. PAHs were first investigated in dust of interiors in Ouargla (Saharan Algeria), concurrently with n-alkanes and polar organics. Settled dust was collected from pre-cleaned surfaces (0.5 m2 each) at 7 internal locations in total from a school, the city hospital and university, and a home. Three sample series were collected 15, 30 days and random after the preliminary cleaning of surfaces. Contemporarily, organic compounds were collected at 15 locations of the target sites by deploying diffusive samplers over the whole study period to obtain molecular signatures of semi-volatile organic fraction. A consolidated procedure consisting of ultra-sonic bath extraction, semi-preparative column chromatography and gas chromatographic - mass spectrometric analysis was applied for chemical characterization of dusts. n-Alkanes ranged from 3.8 to 41 μg/m2 in dust and 0.17-2.42 μg/m3 in gas phase. PAHs concentrations were 17-89 ng/m2 and 45-182 ng/m3, respectively. Caffeine and nicotine were found both in dust (63-2,02 ng/m2 and 7-284 ng/m2, respectively) and as vapors in air (4-416 ng/m3 and 3.5-60 ng/m3). Two sites were affected by cannabinoids, while traces of nonylphenols occurred at all locations. External air was, on the average, more affected by PAHs than the interiors of school and hospital, but not of university. The compound concentrations show that Ouargla city is seriously polluted and requires actions to improve air quality.

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. Copyright © 2015 Elsevier Inc. All rights reserved.

Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4)).

PubMed

Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

2010-09-21

In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air.Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b.

Differential response of surface temperature and atmospheric temperature to the biogeophysical effects of deforestation

NASA Astrophysics Data System (ADS)

Winckler, J.; Reick, C. H.; Lejeune, Q.; Pongratz, J.

2017-12-01

Deforestation influences temperature locally by changing the water, energy and momentum balance. While most observation-based studies and some modeling studies focused on the effects on surface temperature, other studies focused on the effects on near-surface air temperature. However, these two variables may respond differently to deforestation because changes in albedo and surface roughness may alter the land-atmosphere coupling and thus the vertical temperature distribution. Thus it is unclear whether it is possible to compare studies that assess the impacts of deforestation on these two different variables. Here, we analyze the biogeophysical effects of global-scale deforestation in the climate model MPI-ESM separately for surface temperature, 2m-air temperature and temperature the lowest atmospheric model layer. We investigate why the response of these variables differs by isolating the effects of only changing surface albedo and only changing surface roughness and by separating effects that are induced at the location of deforestation (local effects) from effects that are induced by advection and changes in circulation (nonlocal effects). Concerning surface temperature, we find that the local effects of deforestation lead to a global mean warming which is overcompensated by the nonlocal effects (up to 0.1K local warming versus -0.3K nonlocal cooling). The surface warming in the local effects is largely driven by the change in surface roughness while the cooling in the nonlocal effects is largely driven by the change in surface albedo. The nonlocal effects are largely consistent across surface temperature, 2m-air temperature, and the temperature of the lowest atmospheric layer. However, the local effects strongly differ across the three considered variables. The local effects are strong for surface temperature, but substantially weaker in the 2m-air temperature and largely absent in the lowest atmospheric layer. We conclude that studies focusing on the deforestation effects on surface temperature should not be compared to studies focusing on the effects on air temperature. While the local effects on surface temperature are useful for model evaluation, they might be less relevant for local adaptation and mitigation than previously thought because they might largely be absent in the atmosphere.

Haze over Eastern China

NASA Image and Video Library

2017-12-08

A thick layer of haze blanketed the North China Plain on October 9, 2014, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this natural-color image at 2:50 Coordinated Universal Time (10:50 a.m. local time). The haze obscured many features usually visible in MODIS imagery of the area, including China’s largest city, Beijing. On the day this image was acquired, measurements from ground-based sensors at the U.S. Consulate in Beijing reported PM2.5 measurements of 334 micrograms per cubic meter of air. Fine, airborne particulate matter (PM) that is smaller than 2.5 microns (about one thirtieth the width of a human hair) is considered dangerous because it is small enough to enter the passages of the human lungs. Most PM2.5 aerosol particles come from the burning of fossil fuels and biomass (wood fires and agricultural burning). The World Health Organization considers PM2.5 to be safe when it is below 25. Haze in this region tends to worsen in the fall and winter, when cold, heavy air traps pollutants near the surface. In this case, the haze was likely trapped by a temperature inversion. Normally, air is warmest near the surface of the Earth. Occasionally, a mass of warm air will move over cooler air so that the atmosphere actually warms with altitude. Since the cool air does not have the energy to rise through the warm air, vertical circulation slows and air becomes trapped near the surface. Any pollutant that enters the air gets trapped as well, and haze builds up over time. Daily satellite images of the North China Plain show that visible haze began to accumulate on October 7, 2014. NASA image courtesy Jeff Schmaltz, LANCE MODIS Rapid Response. Caption by Adam Voiland. Read more: earthobservatory.nasa.gov/NaturalHazards/view.php?id=8453... Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Opportunities for Saving Energy and Improving Air Quality in Urban Heat Islands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akbari, Hashem

2007-07-01

World energy use is the main contributor to atmospheric CO2. In 2002, about 7.0 giga metric tons of carbon (GtC) were emitted internationally by combustion of gas, liquid, and solid fuels (CDIAC, 2006), 2 to 5 times the amount contributed by deforestation (Brown et al., 1988). The share of atmospheric carbon emissions for the United States from fossil fuel combustion was 1.6 GtC. Increasing use of fossil fuel and deforestation together have raised atmospheric CO{sub 2} concentration some 25% over the last 150 years. According to global climate models and preliminary measurements, these changes in the composition of the atmospheremore » have already begun raising the Earth's average temperature. If current energy trends continue, these changes could drastically alter the Earth's temperature, with unknown but potentially catastrophic physical and political consequences. During the last three decades, increased energy awareness has led to conservation efforts and leveling of energy consumption in the industrialized countries. An important byproduct of this reduced energy use is the lowering of CO{sub 2} emissions. Of all electricity generated in the United States, about one-sixth is used to air-condition buildings. The air-conditioning use is about 400 tera-watt-hours (TWh), equivalent to about 80 million metric tons of carbon (MtC) emissions, and translating to about $40 billion (B) per year. Of this $40 B/year, about half is used in cities that have pronounced 'heat islands'. The contribution of the urban heat island to the air-conditioning demand has increased over the last 40 years and it is currently at about 10%. Metropolitan areas in the United States (e.g., Los Angeles, Phoenix, Houston, Atlanta, and New York City) have typically pronounced heat islands that warrant special attention by anyone concerned with broad-scale energy efficiency (HIG, 2006). The ambient air is primarily heated through three processes: direct absorption of solar radiation, convection of heat from hot surfaces, and man-made heat (exhaust from cars, buildings, etc.). Air is fairly transparent to light--the direct absorption of solar radiation in atmospheric air only raises the air temperature by a small amount. Typically about 90% of solar radiation reaches the Earth's surface and then is either absorbed or reflected. The absorbed radiation on the surface increases the surface temperature. And in turn the hot surfaces heat the air. This convective heating is responsible for the majority of the diurnal temperature range. The contribution of man-made heat (e.g., air conditioning, cars) is very small, compared to the heating of air by hot surfaces, except for the downtown high-rise areas.« less

Overall Effectiveness Measurement at Engine Temperatures with Reactive Film Cooling and Surface Curvature

DTIC Science & Technology

2015-03-26

supplied with hot mainstream gas from a well-stirred reactor operating on a propane/air mixture capable of multiple equivalence ratios. The...consequently the Pr’s were around 2.3 which is more representative of liquids rather than 0.7 of most gases. Case 5 vastly overpredicted η showing the...performance engines, an afterburner may be added for additional power which exposes aft sections and the nozzle of the engine to a high temperature flame

Proceedings of the 1980 Tri-Service Conference on Corrosion, 5-7 November 1980, US Air Force Academy, Colorado. Volume 2

DTIC Science & Technology

1980-11-01

the potential fiield vacialions at a plane parallel to the sample surface. The signals can also be recorded on a storage oscilloscope and photographed... storage , and overhaul is performed at the J jappropriate depot(s). If a program requires intensive management, a project manager is dcsignated and...the program include the conduct of a Triennial inspection of DARCOM facilities, thc establishment of a Materiel Deterioration Information Certer, the

Advection from the North Atlantic as the Forcing of Winter Greenhouse Effect Over Europe

NASA Technical Reports Server (NTRS)

Otterman, J.; Angell, J.; Atlas, R.; Bungato, D.; Shubert, S.; Starr, David OC.; Susskind, J.; Wu, M.-L. C.

2002-01-01

In winter, large interannual fluctuations in the surface temperature are observed over central Europe. Comparing warm February 1990 with cold February 1996, a satellite-retrieved surface (skin) temperature difference of 9.8 K is observed for the region 50-60 degrees N; 5-35 degrees E. Previous studies show that advection from the North Atlantic constitutes the forcing to such fluctuations. The advection is quantified by Index I(sub na), the average of the ocean-surface wind speed over the eastern North Atlantic when the direction is from the southwest (when the wind is from another direction, it counts as a zero speed to the average). Average I(sub na) for February 1990 was 10.6 m/s, but for February 1996 I(sub na) was only 2.4 m/s. A large value of I(sub na) means a strong southwesterly flow which brings warm and moist air into central Europe at low level, producing a steeper tropospheric lapse rate. Strong ascending motions at 700 mb are observed in association with the occurrence of enhanced warm, moist advection from the ocean in February 1990 producing clouds and precipitation. Total precipitable water and cloud-cover fraction have larger values in February 1990 than in 1996. The difference in the greenhouse effect between these two scenarios, this reduction in heat loss to space, can be translated into a virtual radiative heating of 2.6 W/square m above the February 1990 surface/atmosphere system, which contributes to a warming of the surface on the order of 2.6 K. Accepting this estimate as quantitatively meaningful, we evaluate the direct effect, the rise in the surface temperature in Europe as a result of maritime-air inflow, as 7.2 K (9.8 K-2.6 K). Thus, fractional reinforcement by the greenhouse effect is 2.6/7.2, or 36%, a substantial positive feedback.

Method of bonding a conductive layer on an electrode of an electrochemical cell

DOEpatents

Bowker, J.C.; Singh, P.

1989-08-29

A dense, electronically conductive interconnection layer is bonded onto a porous, tubular, electronically conductive air electrode structure, optionally supported by a ceramic support, by (A) providing an air electrode surface, (B) forming on a selected portion of the electrode surface, without the use of pressure, particles of LaCrO[sub 3] doped with an element selected from the group consisting of Sr, Mg, Ca, Ba, Co, and mixtures thereof, where the particles have a deposit on their surface comprising calcium oxide and chromium oxide; (C) heating the particles with the oxide surface deposit in an oxidizing atmosphere at from 1,300 C to 1,550 C, without the application of pressure, to provide a dense, sintered, interconnection material bonded to the air electrode, where calcium and chromium from the surface deposit are incorporated into the structure of the LaCrO[sub 3]. A solid electrolyte layer can be applied to the uncovered portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell. 4 figs.

Method of bonding a conductive layer on an electrode of an electrochemical cell

DOEpatents

Bowker, Jeffrey C.; Singh, Prabhakar

1989-01-01

A dense, electronically conductive interconnection layer 26 is bonded onto a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) providing an air electrode surface, (B) forming on a selected portion of the electrode surface 24, without the use of pressure, particles of LaCrO.sub.3 doped with an element selected from the group consisting of Sr, Mg, Ca, Ba, Co, and mixtures thereof, where the particles have a deposit on their surface comprising calcium oxide and chromium oxide; (C) heating the particles with the oxide surface deposit in an oxidizing atmosphere at from 1,300.degree. C. to 1,550.degree. C., without the application of pressure, to provide a dense, sintered, interconnection material 26 bonded to the air electrode 16, where calcium and chromium from the surface deposit are incorporated into the structure of the LaCrO.sub.3. A solid electrolyte layer 18 can be applied to the uncovered portion of the air electrode, and a fuel electrode 20 can be applied to the solid electrolyte, to provide an electrochemical cell 10.

Superhydrophobic materials for drug delivery

NASA Astrophysics Data System (ADS)

Yohe, Stefan Thomas

Superhydrophobicity is a property of material surfaces reflecting the ability to maintain air at the solid-liquid interface when in contact with water. These surfaces have characteristically high apparent contact angles, by definition exceeding 150°, as a result of the composite material-air surface formed under an applied water droplet. Superhydrophobic surfaces were first discovered on naturally occurring substrates, and have subsequently been fabricated in the last several decades to harness these favorable surface properties for a number of emerging applications, including their use in biomedical settings. This work describes fabrication and characterization of superhydrophobic 3D materials, as well as their use as drug delivery devices. Superhydrophobic 3D materials are distinct from 2D superhydrophobic surfaces in that air is maintained not just at the surface of the material, but also within the bulk. When the superhydrophobic 3D materials are submerged in water, water infiltrates slowly and continuously as a new water-air-material interface is formed with controlled displacement of air. Electrospinning and electrospraying are used to fabricate superhydrophobic 3D materials utilizing blends of the biocompatible polymers poly(epsilon-caprolactone) and poly(caprolactone-co-glycerol monostearate) (PGC-C18). PGC-C18 is significantly more hydrophobic than PCL (contact angle of 116° versus 83° for flat materials), and further additions of PGC-C18 into electrospun meshes and electrosprayed coatings affords increased stability of the entrapped air layer. For example, PCL meshes alone (500 mum thick) take 10 days to fully wet, and with 10% or 30% PGC-C18 addition wetting rates are dramatically slowed to 60% wetted by 77 days and 4% by 75 days, respectively. Stability of the superhydrophobic materials can be further probed with a variety of physio-chemical techniques, including pressure, surfactant containing solutions, and solvents of varying surface tension. Superhydrophobicity is shown to be enhanced with further increases in PGC-C18 content and surface roughness (a decrease in fiber size). We demonstrate the utility of superhydrophobicity as a method for drug delivery. When the camptothecin derivatives SN-38 and CPT-11 are encapsulated within electrospun meshes, changes in air layer stability (due to changes in PGC-C18 content) dictate the rate of drug release by controlling the rate in which water can permeate into the porous 3D electrospun structure. Drug release can be tuned from 2 weeks to >10 weeks from 300 mum meshes, and meshes effectively kill a variety of cancer cell lines (lung, colon, breast) when utilized in a cytotoxicity assay. After determining that air could be used to control the rate of drug release, superhydrophobic 3D materials are explored for three applications. First, meshes are considered as a potential combination reinforcement-drug delivery device for use in resectable colorectal cancer. Second, removal of the air layer in superhydrophobic meshes is used as a method to trigger drug release. The pressure generated from high-intensity focused ultrasound (0.75-4.25 MPa) can remove the air layer spatially and temporally, allowing drug release to be controlled with application of a sufficient treatment. Third, "connective" electrosprayed coatings are deposited on chemically distinct material surfaces, which are both three-dimensional and mechanically robust. In summary, superhydrophobic 3D materials are fabricated and characterized, and are utilized as drug delivery devices. Controlled air removal from these materials offers an entirely new strategy for drug delivery, and is promising for the applications considered in this work as well as many others.

Surface-Based Observations of Contrail Occurrence Over the US, Apr. 1993 to Apr. 1994

NASA Technical Reports Server (NTRS)

Minnis, Patrick; Ayers, J. Kirk; Weaver, Steven P.

1997-01-01

Surface observers stationed at 19 U.S. Air Force Bases and Army Air Stations recorded the daytime occurrence of contrails and cloud fraction on an hourly basis for the period April 1993 through April 1994. Each observation uses one of four main categories to report contrails as unobserved, non-persistent, persistent, and indeterminate. Additional classification includes the co-occurrence of cirrus with each report. The data cover much of the continental U.S. including locations near major commercial air routes. The mean annual frequency of occurrence in unobstructed viewing conditions is 13 percent for these sites. Contrail occurrence varied substantially with location and season. Most contrails occurred during the winter months and least during the summer with a pronounced minimum during July. Although nocturnal observations are not available, it appears that the contrails have a diurnal variation that peaks during mid morning over most areas. Contrails were most often observed in areas near major commercial air corridors and least often over areas far removed from the heaviest air traffic. A significant correlation exists between mean contrail frequency and aircraft fuel usage above 7 km suggesting predictive potential for assessing future contrail effects on climate.

Interface Engineering of Garnet Solid Electrolytes

NASA Astrophysics Data System (ADS)

Cheng, Lei

Solid lithium ion conductors represent a promising class of materials for next generation high energy density batteries, with the potential for enabling use of high capacity Li metal anodes and providing opportunities for novel lithium-free cathode materials. However, highly resistive interfaces stymie their practical use. This urgent scientific challenge requires mechanistic understanding of ion transport at interfaces, as well as development of novel processes to achieve low interfacial resistances. The goal of this PhD dissertation was to generate fundamental understandings of garnet-structured Al substituted Li7La3Zr2O 12 (LLZO) electrolyte surfaces and interfaces with lithium metal electrodes. Specifically in this research, the topmost surface microstructure, local chemical environment, and surface chemistry were carefully studied. The ceramic processing of garnet is discussed and ways to control the sintering behavior and microstructures were explored and successfully demonstrated. Factors contributing to high interfacial resistance were systematically studied. The source of the high interfacial impedance has been traced to the presence of Li2CO 3 on pellet surfaces resulting from air exposure after processing. In addition, it was discovered that surface grain boundaries are surprisingly fast ion transport pathways and surface microstructure is critically important to lithium ion transport at interfaces. Complex homo- and heterostructured LLZO solid electrolytes with controllable surface and bulk microstructures were successfully fabricated, which allowed the comparison and separation of the contribution from the surface and the bulk. Engineered pellet surfaces allowed us to achieve the lowest interfacial resistance ever reported for this composition, resulting in significantly improved cycling behavior. Lastly, it was found that LLZO surfaces can be effectively stabilized under air exposure conditions, preventing Li2CO3 formation and maintaining low interfacial resistances. This opens new opportunities for garnet solid electrolyte in practical applications.

Observations of the convective plume of a lake under cold-air advective conditions

NASA Technical Reports Server (NTRS)

Bill, R. G., Jr.; Sutherland, R. A.; Bartholic, J. F.; Chen, E.

1978-01-01

Moderating effects of Lake Apopka, Florida, on downwind surface temperatures were evaluated under cold-air advective conditions. Point temperature measurements north and south of the lake and data obtained from a thermal scanner flown at 1.6 km indicate that surface temperatures directly downwind may be higher than surrounding surface temperatures by as much as 5 C under conditions of moderate winds (about 4 m/s). No substantial temperature effects were observed with surface wind speed less than 1 m/s. Fluxes of sensible and latent heat from Lake Apopka were calculated from measurements of lake temperature, net radiation, relative humidity, and air temperature above the lake. Bulk transfer coefficients and the Bowen ratio were calculated and found to be in agreement with reported data for nonadvective conditions.

Modeling of the anthropogenic heat flux and its effect on air quality over the Yangtze River Delta region, China

NASA Astrophysics Data System (ADS)

Xie, M.; Liao, J.; Wang, T.; Zhu, K.; Zhuang, B.; Han, Y.; Li, M.; Li, S.

2015-11-01

Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and the diurnal variations into the simulations. By running this upgraded WRF/Chem for two typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over YRD have been growing in recent decades. In 2010, the annual mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m-2 respectively, with the high values of 113.5 W m-2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 °C in January and 1.4 °C in July, the planetary boundary layer height rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s-1 in January and 0.5 m s-1 in July, with higher increment at night. And the enhanced vertical movement can transport more moisture to higher levels, which causes the decrease of water vapor at the ground level and the increase in the upper PBL, and thereby induces the accumulative precipitation to increase by 15-30 % over the megacities in July. The adding AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near surface and increase at the upper levels, due mainly to the increases of PBLH, surface wind speed and upward air vertical movement. But surface O3 concentrations increase in the urban areas, with maximum changes of 2.5 ppb in January and 4 ppb in July. Chemical direct (the rising up of air temperature directly accelerate surface O3 formation) and indirect (the decrease in NOx at the ground results in the increase of surface O3) effects can play a significant role in O3 changes over this region. The meteorology and air pollution predictions in and around large urban areas are highly sensitive to the anthropogenic heat inputs, suggesting that AH should be considered in any climate and air quality assessment.

Modeling of the anthropogenic heat flux and its effect on regional meteorology and air quality over the Yangtze River Delta region, China

NASA Astrophysics Data System (ADS)

Xie, Min; Liao, Jingbiao; Wang, Tijian; Zhu, Kuanguang; Zhuang, Bingliang; Han, Yong; Li, Mengmeng; Li, Shu

2016-05-01

Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and diurnal variations into the simulations. By running this upgraded WRF/Chem for 2 typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over the YRD have been growing in recent decades. In 2010, the annual-mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m-2, respectively, with the high value of 113.5 W m-2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 °C in January and 1.4 °C in July, the PBLH (planetary boundary layer height) rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s-1 in January and 0.5 m s-1 in July, with a higher increment at night. The enhanced vertical movement can transport more moisture to higher levels, which causes the decrease in water vapor at ground level and the increase in the upper PBL (planetary boundary layer), and thereby induces the accumulative precipitation to increase by 15-30 % over the megacities in July. The adding of AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near the surface and increase at the upper levels, due mainly to the increases in PBLH, surface wind speed and upward air vertical movement. But surface O3 concentrations increase in the urban areas, with maximum changes of 2.5 ppb in January and 4 ppb in July. Chemical direct (the rising up of air temperature directly accelerates surface O3 formation) and indirect (the decrease in NOx at the ground results in the increase in surface O3) effects can play a significant role in O3 changes over this region. The meteorology and air pollution predictions in and around large urban areas are highly sensitive to the anthropogenic heat inputs, suggesting that AH should be considered in the climate and air quality assessments.

Oil Palm expansion over Southeast Asia: land use change and air quality

NASA Astrophysics Data System (ADS)

Silva, S. J.; Heald, C. L.; Geddes, J.; Marlier, M. E.; Austin, K.; Kasibhatla, P. S.

2015-12-01

Over recent decades oil palm plantations have rapidly expanded across Southeast Asia (SEA). Much of this expansion has come at the expense of natural forests and grasslands. Aircraft measurements from a 2008 campaign, OP3, found that oil palm plantations emit as much as 7 times more isoprene than nearby natural forests. Furthermore, SEA is a rapidly developing region, with increasing urban population, and growing air quality concerns. Thus, SEA represents an ideal case study to examine the impacts of land use change on air quality in the region, and whether those changes can be detected from satellite observations of atmospheric composition. We investigate the impacts of historical and future oil palm expansion in SEA using satellite data, high-resolution land maps, and the chemical transport model GEOS-Chem. We examine the impact of palm plantations on surface-atmosphere processes (dry deposition, biogenic emissions). We show the sensitivity of air quality to current and future oil palm expansion scenarios, and discuss the limitations of current satellite measurements in capturing these changes. Our results indicate that while the impact of oil palm expansion on air quality can be significant, the retrieval error and sensitivity of the satellite measurements limit our ability to observe these impacts from space.

Maintenance-free lead acid battery for inertial navigation systems aircraft

NASA Astrophysics Data System (ADS)

Johnson, William R.; Vutetakis, David G.

1995-05-01

Historically, Aircraft Inertial Navigation System (INS) Batteries have utilized vented nickel-cadmium batteries for emergency DC power. The United States Navy and Air Force developed separate systems during their respective INS developments. The Navy contracted with Litton Industries to produce the LTN-72 and Air Force contracted with Delco to produce the Carousel IV INS for the large cargo and specialty aircraft applications. Over the years, a total of eight different battery national stock numbers (NSNs) have entered the stock system along with 75 battery spare part NSNs. The Standard Hardware Acquisition and Reliability Program is working with the Aircraft Battery Group at Naval Surface Warfare Center Crane Division, Naval Air Systems Command (AIR 536), Wright Laboratory, Battelle Memorial Institute, and Concorde Battery Corporation to produce a standard INS battery. This paper discusses the approach taken to determine whether the battery should be replaced and to select the replacement chemistry. The paper also discusses the battery requirements, aircraft that the battery is compatible with, and status of Navy flight evaluation. Projected savings in avoided maintenance in Navy and Air Force INS Systems is projected to be $14.7 million per year with a manpower reduction of 153 maintenance personnel. The new INS battery is compatible with commercially sold INS systems which represents 66 percent of the systems sold.

Air powder abrasive treatment as an implant surface cleaning method: a literature review.

PubMed

Tastepe, Ceylin S; van Waas, Rien; Liu, Yuelian; Wismeijer, Daniel

2012-01-01

To evaluate the air powder abrasive treatment as an implant surface cleaning method for peri-implantitis based on the existing literature. A PubMed search was conducted to find articles that reported on air powder abrasive treatment as an implant surface cleaning method for peri-implantitis. The studies evaluated cleaning efficiency and surface change as a result of the method. Furthermore, cell response toward the air powder abrasive-treated discs, reosseointegration, and clinical outcome after treatment is also reported. The PubMed search resulted in 27 articles meeting the inclusion criteria. In vitro cleaning efficiency of the method is reported to be high. The method resulted in minor surface changes on titanium specimens. Although the air powder abrasive-treated specimens showed sufficient levels of cell attachment and cell viability, the cell response decreased compared with sterile discs. Considerable reosseointegration between 39% and 46% and improved clinical parameters were reported after treatment when applied in combination with surgical treatment. The results of the treatment are influenced by the powder type used, the application time, and whether powder was applied surgically or nonsurgically. The in vivo data on air powder abrasive treatment as an implant surface cleaning method is not sufficient to draw definitive conclusions. However, in vitro results allow the clinician to consider the method as a promising option for implant surface cleaning in peri-implantitis treatment.

Frequency-depth dependent spherical reflection response from the sea surface - A transmission experiment

NASA Astrophysics Data System (ADS)

Wehner, D.; Landrø, M.; Amundsen, L.; Westerdahl, H.

2018-05-01

In academia and the industry, there is increasing interest in generating and recording low seismic frequencies, which lead to better data quality, deeper signal penetration and can be important for full-waveform inversion. The common marine seismic source in acquisition is the air gun which is towed behind a vessel. The frequency content of the signal produced by the air gun mainly depends on its source depth as there are two effects which are presumed to counteract each other. First, there is the oscillating air bubble generated by the air gun which leads to more low frequencies for shallow source depths. Secondly, there is the interference of the downgoing wave with the first reflection from the sea surface, referred to as the ghost, which leads to more low frequencies for deeper source depths. It is still under debate whether it is beneficial to place the source shallow or deep to generate the strongest signal for frequencies below 5 Hz. Therefore, the ghost effect is studied in more detail by measuring the transmission at the water-air interface. We conduct experiments in a water tank where a small-volume seismic source is fired at different depths below the water surface to investigate how the ghost varies with frequency and depth. The signal from the seismic source is recorded with hydrophones inside water and air during the test to estimate the transmitted signal through the interface. In a second test, we perform experiments with an acoustic source located in air which is fired at different elevations above the water surface. The source in air is a starter gun and the signals are again recorded in water and air. The measured data indicates an increasing transmission of the signal through the water-air interface when the source is closer to the water surface which leads to a decreasing reflection for sources close to the surface. The measured results are compared with modeled data and the existing theory. The observed increase in transmission for shallow source depths could be explained by the theory of a spherical wave front striking the interface instead of assuming a plane wave front. The difference can be important for frequencies below 1 Hz. The results suggest that deploying a few sources very shallow during marine seismic acquisition could be beneficial for these very low frequencies. In addition, the effect of a spherical wave front might be considered for modeling far field signatures of seismic sources for frequencies below 1 Hz.

Circumventing shallow air contamination in Mid Ocean Ridge Basalts

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sujoy; Parai, Rita; Tucker, Jonathan; Middleton, Jennifer; Langmuir, Charles

2016-04-01

Noble gases in mantle-derived basalts provide a rich portrait of mantle degassing and surface-interior volatile exchange. However, the ubiquity of shallow-level air contamination frequently obscures the mantle noble gas signal. In a majority of samples, shallow air contamination dominates the noble gas budget. As a result, reconstructing the variability in heavy noble gas mantle source compositions and inferring the history of deep recycling of atmospheric noble gases is difficult. For example, in the gas-rich popping rock 2ΠD43, 129Xe/130Xe ratios reach 7.7±0.23 in individual step-crushes, but the bulk composition of the sample is close to air (129Xe/130Xe of 6.7). Here, we present results from experiments designed to elucidate the source of shallow air contamination in MORBs. Step-crushes were carried out to measure He, Ne, Ar and Xe isotopic compositions on two aliquots of a depleted popping glass that was dredged from between the Kane and Atlantis Fracture Zones of the Mid-Atlantic Ridge in May 2012. One aliquot was sealed in ultrapure N2 after dredge retrieval, while the other aliquot was left exposed to air for 3.5 years. The bulk 20Ne/22Ne and 129Xe/130Xe ratios measured in the aliquot bottled in ultrapure N2 are 12.3 and 7.6, respectively, and are nearly identical to the estimated mantle source values. On the other hand, step crushes in the aliquot left exposed to air for several years show Ne isotopic compositions that are shifted towards air, with a bulk 20Ne/22Ne of 11.5; the bulk 129Xe/130Xe, however, was close to 7.6. These results indicate that lighter noble gases exchange more efficiently between the bubbles trapped in basalt glass and air, suggesting a diffusive or kinetic mechanism for the incorporation of the shallow air contamination. Importantly, in Ne-Ar or Ar-Xe space, step-crushes from the bottled aliquot display a trend that can be easily fit with a simple two-component hyperbolic mixing between mantle and atmosphere noble gases. Step-crushes in the aliquot left exposed to air display significantly more scatter, which makes it difficult to fit a two-component mixing hyperbola and obtain the mantle source value for this aliquot. In summary, our simple and inexpensive experiment demonstrates that at least in some samples, significant air contamination is added after dredge retrieval from the ocean floor. Bottling samples in ultrapure N2 upon dredge retrieval can largely eliminate this component of shallow-level air contamination. As a result, the number of step crushes required to characterize a sample decreases and estimating the mantle source compositions of the basalts becomes significantly easier, which in turn leads to more refined estimates of mantle degassing and regassing rates.

Report of the analysis of the joint medium range air to surface missile program

NASA Astrophysics Data System (ADS)

1980-01-01

The objective of this effort completed between July, 1979 and January, 1980 was to investigate technical alternatives and make recommendations concerning management approaches to accomplish the project goals. The purpose of this report is to formalize those recommendations and to identify future courses of action alternatives. The basic concepts incorporated in a supersonic stand-off, air-to-surface missile have existed in Navy advance planning for many years. Navy action on this concept was formalized in 1967 with the decision to initiate a funded technology program to produce a system technology prototype of an advance tactical stand-off missile. Parallel development of propulsion, guidance, and other subsystem technologies conducted by the Air Force, industry, and other countries have also contributed to the current technology base. In May 1978, the Chief of Naval Operations established a requirement for a survivable medium range air-to-surface missile with the issuance of operational requirement W-0650-TW, 'Medium Range Air-to-Surface Missile'. The requirements delineate the need for an offensive air-to-surface missile that can penetrate and survive against defenses expected to be encountered in the 80's and 90's.

Concentrations, atmospheric partitioning, and air-water/soil surface exchange of polychlorinated dibenzo-p-dioxin and dibenzofuran along the upper reaches of the Haihe River basin, North China.

PubMed

Nie, Zhiqiang; Die, Qingqi; Yang, Yufei; Tang, Zhenwu; Wang, Qi; Huang, Qifei

2014-01-01

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF) were overall measured and compared in ambient air, water, soils, and sediments along the upper reaches of the Haihe River of North China, so as to evaluate their concentrations, profiles, and to understand the processes of gas-particle partitioning and air-water/soil exchange. The following results were obtained: (1) The average concentrations (toxic equivalents, TEQs) of 2,3,7,8-PCDD/PCDF in air, water, sediment, and soil samples were 4,855 fg/m(3), 9.5 pg/L, 99.2 pg/g dry weight (dw), and 56.4 pg/g (203 fg TEQ/m(3), 0.46 pg TEQ/L, 2.2 pg TEQ/g dw, and 1.3 pg TEQ/g, respectively), respectively. (2) Although OCDF, 1,2,3,4,6,7,8-HpCDF, OCDD, and 1,2,3,4,6,7,8-HpCDD were the dominant congeners among four environmental sinks, obvious discrepancies of these congener and homologue patterns of PCDD/PCDF were observed still. (3) Significant linear correlations for PCDD/PCDF were observed between the gas-particle partition coefficient (K p) and the subcooled liquid vapor pressure (P L (0)) and octanol-air partition coefficient (K oa). (4) Fugacity fraction values of air-water exchange indicated that most of PCDD/PCDF homologues were dominated by net volatilization from water into air. The low-chlorinated PCDD/PCDF (tetra- to hexa-) presented a strong net volatilization from the soil into air, while high-chlorinated PCDD/PCDF (hepta- to octa-) were mainly close to equilibrium for air-soil exchange.

Integration of minisolenoids in microfluidic device for magnetic bead-based immunoassays

NASA Astrophysics Data System (ADS)

Liu, Yan-Jun; Guo, Shi-Shang; Zhang, Zhi-Ling; Huang, Wei-Hua; Baigl, Damien; Chen, Yong; Pang, Dai-Wen

2007-10-01

Microfluidic devices with integrated minisolenoids, microvalves, and channels have been fabricated for fast and low-volume immunoassay using superparamagnetic beads and well-known surface bioengineering protocols. A magnetic reaction area can be formed in the microchannel, featuring a high surface-to-volume ratio and low diffusion distances for the reagents to the bead surface. Such a method has the obvious advantage of easy implementation at low cost. Moreover, the minisolenoids can be switched on or off and the magnetic field intensity can be tuned on demand. Fluids can be manipulated by controlling the integrated air-pressure-actuated microvalves. Accordingly, magnetic bead-based immunoassay, as a typical example of biochemical detection and analysis, has been successfully performed on the integrated microfluidic device automatically in longitudinal mode. With a sample consumption of 0.5μl and a total assay time of less than 15min, goat immunoglobulin G was detected and the method exhibited a detection limit of 4.7ng/ml.

Air-coupled acoustic thermography for in-situ evaluation

NASA Technical Reports Server (NTRS)

Zalameda, Joseph N. (Inventor); Winfree, William P. (Inventor); Yost, William T. (Inventor)

2010-01-01

Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and/or repeatability, sound and/or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

Method of doping interconnections for electrochemical cells

DOEpatents

Pal, Uday B.; Singhal, Subhash C.; Moon, David M.; Folser, George R.

1990-01-01

A dense, electronically conductive interconnection layer 26 is bonded on a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) forming a layer of oxide particles of at least one of the metals Ca, Sr, Co, Ba or Mg on a part 24 of a first surface of the air electrode 16, (B) heating the electrode structure, (C) applying a halide vapor containing at least lanthanum halide and chromium halide to the first surface and applying a source of oxygen to a second opposite surface of the air electrode so that they contact at said first surface, to cause a reaction of the oxygen and halide and cause a dense lanthanum-chromium oxide structure to grow, from the first electrode surface, between and around the oxide particles, where the metal oxide particles get incoporated into the lanthanum-chromium oxide structure as it grows thicker with time, and the metal ions in the oxide particles diffuse into the bulk of the lanthamum-chromium oxide structure, to provide a dense, top, interconnection layer 26 on top of the air electrode 16. A solid electrolyte layer 18 can be applied to the uncovered portion of the air electrode, and a fuel electrode 20 can be applied to the solid electrolyte, to provide an electrochemical cell 10.

Volatile organic compounds in the marine troposphere and surface oceans: methods, measurements and biogeochemical implications

NASA Astrophysics Data System (ADS)

Hudson, Edward

2010-09-01

Volatile organic compounds (VOCs), among them non-methane hydrocarbons (NMHCs) and low molecular weight carbonyl compounds (aldehydes and ketones), affect the oxidative capacity of the atmosphere and thus pollutant lifetimes and global climate. VOCs in the surface oceans may be transported into, or derived from, the atmosphere. This thesis describes the development and optimization of chromatographic and preconcentration methods to determine volatile organic compounds (VOCs) in surface seawater and marine air, and their use to explore VOC distribution and fluxes at the seaair interface. It includes the first measurements of many carbonyl compounds in temperate and subarctic marine waters and the first estimates of fluxes of several aldehydes from the ocean surface into the marine atmosphere. Sea surface air, size-fractionated marine aerosols, and surface ocean water dissolved organic matter were simultaneously sampled in the Nordic seas. Nineteen C2-C7 NMHCs were quantified in the air samples. Site-to-site variability in NMHC concentrations was high, suggesting variable, local sources. The aerosols consisted mainly of inorganic marine material, but a culturable bacterium identified as Micrococcus luteus was also isolated from the 9.9 -- 18 mum fraction, suggesting organic matter may be transferred from the surface oceans to the atmosphere by marine aerosols. Lastly, a number of VOCs, including acetone, were detected in the seawater samples using solid-phase microextraction (SPME), leading to the subsequent development of an SPME application for carbonyl compounds in seawater. A mobile, economical and solventless method for the detection and quantification of carbonyl compounds in seawater, a matrix of global importance, was developed. The compounds were derivatized using O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA)and then pre-concentrated by SPME for gas chromatography with mass spectrometric (GC/MS) or flame ionization (GC-FID) detection. The method was first optimized for acetone and subsequently for a suite of 23 C1 -- C9 carbonyl compounds. The buffering capacity of seawater necessitated the use of artificial seawater for standard preparation, and acidification of seawater samples to achieve the method's optimum pH of 3.7. Sparging with UHP argon, and C-18 solid phase extraction of the dissolved PFBHA, were found to be the most effective methods for reducing the high process blanks observed for C1-C3 carbonyl compounds. Using this technique, the first acetone measurements for North Atlantic and Arctic waters (5.5 --9.6 nM acetone), the first surface water measurements of carbonyl compounds from the St. Lawrence Estuary (including glyoxal, methylglyoxal and 2,4-pentanedione), and concentrations of 11 C1 - C9 carbonyl compounds in surface seawaters from the Labrador Sea and from the Scotian Shelf were reported. This represents the first survey of these compounds in seawaters outside of the tropics. The results suggest that the North Atlantic is a sink for glyoxal and formaldehyde. Fluxes of several C4 - C9 aldehydes from the ocean to the atmosphere were estimated to be -13 to +14 mumol/m2/day.

30 CFR 56.13012 - Compressor air intakes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressor air intakes. 56.13012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that only...

30 CFR 56.13012 - Compressor air intakes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressor air intakes. 56.13012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that only...

30 CFR 56.13012 - Compressor air intakes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressor air intakes. 56.13012 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that only...

30 CFR 56.13012 - Compressor air intakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13012 Compressor air intakes. Compressor air intakes shall be installed to ensure that only... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressor air intakes. 56.13012 Section 56...

Air Deployable Underwater Glider and Buoy Development for Arctic and Oceanographic Sensing

NASA Astrophysics Data System (ADS)

Legnos, P. J.

2013-12-01

LBI developed under a NOAA SBIR the AXIB (Airborne eXpendable Ice Buoy). The initial buoy was developed to collect barometric pressure, air temperature two meters above the surface and sea surface or ice temperature. A number of these AXIBs have been successfully deployed in the Arctic and Antarctic. Currently we are in the process of integrating additional sensors to include an anemometer, thermistor chain and hydrophones. Further development is in process for the integration of solar and wind recharging systems and lower power sensors and processing LBI developed under an ONR SBIR Grant two Air Deployable Underwater Gliders. They are primarily designed for air deployment from Navy P-3 or P-8 Aircraft though easily deployed from other aircraft or helicopters. The A-size (4 7/8'dia. X 36' long) and the 12 ¾ (12 ¾' dia. X 9' 9' long). On the development side we are in the process of integrating sensors and enhancing the battery storage capacity. We anticipate a broad range of Oceanographic sensing missions for these Gliders.

Extensive Viable Middle East Respiratory Syndrome (MERS) Coronavirus Contamination in Air and Surrounding Environment in MERS Isolation Wards.

PubMed

Kim, Sung-Han; Chang, So Young; Sung, Minki; Park, Ji Hoon; Bin Kim, Hong; Lee, Heeyoung; Choi, Jae-Phil; Choi, Won Suk; Min, Ji-Young

2016-08-01

The largest outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) outside the Middle East occurred in South Korea in 2015 and resulted in 186 laboratory-confirmed infections, including 36 (19%) deaths. Some hospitals were considered epicenters of infection and voluntarily shut down most of their operations after nearly half of all transmissions occurred in hospital settings. However, the ways that MERS-CoV is transmitted in healthcare settings are not well defined. We explored the possible contribution of contaminated hospital air and surfaces to MERS transmission by collecting air and swabbing environmental surfaces in 2 hospitals treating MERS-CoV patients. The samples were tested by viral culture with reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescence assay (IFA) using MERS-CoV Spike antibody, and electron microscopy (EM). The presence of MERS-CoV was confirmed by RT-PCR of viral cultures of 4 of 7 air samples from 2 patients' rooms, 1 patient's restroom, and 1 common corridor. In addition, MERS-CoV was detected in 15 of 68 surface swabs by viral cultures. IFA on the cultures of the air and swab samples revealed the presence of MERS-CoV. EM images also revealed intact particles of MERS-CoV in viral cultures of the air and swab samples. These data provide experimental evidence for extensive viable MERS-CoV contamination of the air and surrounding materials in MERS outbreak units. Thus, our findings call for epidemiologic investigation of the possible scenarios for contact and airborne transmission, and raise concern regarding the adequacy of current infection control procedures. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Impacts of spectral nudging on the simulated surface air temperature in summer compared with the selection of shortwave radiation and land surface model physics parameterization in a high-resolution regional atmospheric model

NASA Astrophysics Data System (ADS)

Park, Jun; Hwang, Seung-On

2017-11-01

The impact of a spectral nudging technique for the dynamical downscaling of the summer surface air temperature in a high-resolution regional atmospheric model is assessed. The performance of this technique is measured by comparing 16 analysis-driven simulation sets of physical parameterization combinations of two shortwave radiation and four land surface model schemes of the model, which are known to be crucial for the simulation of the surface air temperature. It is found that the application of spectral nudging to the outermost domain has a greater impact on the regional climate than any combination of shortwave radiation and land surface model physics schemes. The optimal choice of two model physics parameterizations is helpful for obtaining more realistic spatiotemporal distributions of land surface variables such as the surface air temperature, precipitation, and surface fluxes. However, employing spectral nudging adds more value to the results; the improvement is greater than using sophisticated shortwave radiation and land surface model physical parameterizations. This result indicates that spectral nudging applied to the outermost domain provides a more accurate lateral boundary condition to the innermost domain when forced by analysis data by securing the consistency with large-scale forcing over a regional domain. This consequently indirectly helps two physical parameterizations to produce small-scale features closer to the observed values, leading to a better representation of the surface air temperature in a high-resolution downscaled climate.

Statistics of surface divergence and their relation to air-water gas transfer velocity

NASA Astrophysics Data System (ADS)

Asher, William E.; Liang, Hanzhuang; Zappa, Christopher J.; Loewen, Mark R.; Mukto, Moniz A.; Litchendorf, Trina M.; Jessup, Andrew T.

2012-05-01

Air-sea gas fluxes are generally defined in terms of the air/water concentration difference of the gas and the gas transfer velocity,kL. Because it is difficult to measure kLin the ocean, it is often parameterized using more easily measured physical properties. Surface divergence theory suggests that infrared (IR) images of the water surface, which contain information concerning the movement of water very near the air-water interface, might be used to estimatekL. Therefore, a series of experiments testing whether IR imagery could provide a convenient means for estimating the surface divergence applicable to air-sea exchange were conducted in a synthetic jet array tank embedded in a wind tunnel. Gas transfer velocities were measured as a function of wind stress and mechanically generated turbulence; laser-induced fluorescence was used to measure the concentration of carbon dioxide in the top 300 μm of the water surface; IR imagery was used to measure the spatial and temporal distribution of the aqueous skin temperature; and particle image velocimetry was used to measure turbulence at a depth of 1 cm below the air-water interface. It is shown that an estimate of the surface divergence for both wind-shear driven turbulence and mechanically generated turbulence can be derived from the surface skin temperature. The estimates derived from the IR images are compared to velocity field divergences measured by the PIV and to independent estimates of the divergence made using the laser-induced fluorescence data. Divergence is shown to scale withkLvalues measured using gaseous tracers as predicted by conceptual models for both wind-driven and mechanically generated turbulence.

Comparison of MODIS-derived land surface temperature with air temperature measurements

NASA Astrophysics Data System (ADS)

Georgiou, Andreas; Akçit, Nuhcan

2017-09-01

Air surface temperature is an important parameter for a wide range of applications such as agriculture, hydrology and climate change studies. Air temperature data is usually obtained from measurements made in meteorological stations, providing only limited information about spatial patterns over wide areas. The use of remote sensing data can help overcome this problem, particularly in areas with low station density, having the potential to improve the estimation of air surface temperature at both regional and global scales. Land Surface (skin) Temperatures (LST) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra and Aqua satellite platforms provide spatial estimates of near-surface temperature values. In this study, LST values from MODIS are compared to groundbased near surface air (Tair) measurements obtained from 14 observational stations during 2011 to 2015, covering coastal, mountainous and urban areas over Cyprus. Combining Terra and Aqua LST-8 Day and Night acquisitions into a mean monthly value, provide a large number of LST observations and a better overall agreement with Tair. Comparison between mean monthly LSTs and mean monthly Tair for all sites and all seasons pooled together yields a very high correlation and biases. In addition, the presented high standard deviation can be explained by the influence of surface heterogeneity within MODIS 1km2 grid cells, the presence of undetected clouds and the inherent difference between LST and Tair. However, MODIS LST data proved to be a reliable proxy for surface temperature and mostly for studies requiring temperature reconstruction in areas with lack of observational stations.

Air Bag Applies Uniform Bonding Pressure

NASA Technical Reports Server (NTRS)

Gillespie, C. A.

1982-01-01

Air-bag box applies constant uniform pressure to tiles and other objects undergoing adhesive bonding. Box is basically a compliant clamp with adjustable force and position. Can be used on irregular surfaces as well as on flat ones. Pressurized air is fed to bag through a tube so that it expands, filling the box and pressing against work. Bag adopts a contour that accommodates surface under open side of box.

An experimental investigation on the effects of freestream turbulence intensity on film cooling effectiveness and heat transfer coefficient for an anti-vortex hole

NASA Astrophysics Data System (ADS)

Hayes, Stephen Andrew

Film cooling is used to thermally protect combustor and turbine components by creating a layer of relatively cooler air than the freestream air to insulate the components from the hot freestream gases. This relatively cooler air is taken from upstream in the high-pressure compressor section at a loss to the engine efficiency, and therefore must be used as effectively as possible. The efficiency gained from increasing the turbine inlet temperature outweighs the loss due to extracting air from the compressor section if the cooling air is used effectively. A novel anti-vortex hole (AVH) geometry has been investigated experimentally through a transient infrared thermography technique to study the film cooling effectiveness and surface convective heat transfer coefficients for varying blowing ratio and freestream turbulence intensity. A major concern with the AVH will be how the secondary jets counteract the main counter rotating vortex (CRV) pair at increased freestream turbulence levels. This is the first experimental facility to study the effects of higher freestream turbulence levels on an AVH geometry. Furthermore, this is the first experimental investigation to report centerline film cooling effectiveness and the convective heat transfer coefficient that had not been reported in prior studies. The AVH geometry is designed with two secondary holes stemming from a main cooling hole; these holes attempt to diffuse the coolant jet and mitigate the vorticity produced by conventional straight holes. This geometry shows improved results at low turbulence intensities compared to conventional straight holes. Three freestream turbulence intensities of 1, 7.5, and 11.7% were investigated at blowing ratios of 0.5, 1.0, 1.5, and 2.0 to form a test matrix of twelve different test conditions. Results showed that the higher freestream turbulence conditions were beneficial in the performance of the AVH. Increasing the blowing ratio at all turbulence levels also improved film cooling effectiveness both span-averaged and on the centerline. The highest performing case was at a turbulence intensity of 7.5% and a blowing ratio of 2.0. The 11.7% cases outperformed the 1% cases, but it appears that at 11.7% cases that the higher freestream turbulence reduces the performance of the secondary holes compared to the 7.5% cases. Increasing the blowing ratio and turbulence intensity will result in a higher heat transfer coefficient, and thus must be taken into account for future designs.

Adsorption of Egg-PC to an Air/Water and Triolein/Water Bubble Interface: Use of the 2-Dimensional Phase Rule to Estimate the Surface Composition of a Phospholipid/Triolein/Water Surface as a Function of Surface Pressure

PubMed Central

Mitsche, Matthew A.; Wang, Libo; Small, Donald M.

2010-01-01

Phospholipid monolayers play a critical role in the structure and stabilization of biological interfaces including all membranes, the alveoli of the lung, fat droplets in adipose tissue, and lipoproteins. The behavior of phospholipids in bilayers and at an air-water interface is well understood. However, the study of phospholipids at oil-water interfaces is limited due to technical challenges. In this study, egg-phosphatidylcholine (EPC) was deposited from small unilamellar vesicles onto a bubble of either air or triolein (TO) formed in a low salt buffer. The surface tension (γ) was measured using a drop tensiometer. We observed that EPC binds irreversibly to both interfaces and at equilibrium exerts ~12 and 15 mN/m of pressure (Π) at an air and TO interface, respectively. After EPC was bound to the interface, the unbound EPC was washed out of the cuvette and the surface was compressed to study the Π/area relationship. To determine the surface concentration (Γ), which cannot be measured directly, compression isotherms from a Langmuir trough and drop tensiometer were compared. The air-water interfaces had identical characteristics using both techniques, thus Γ on the bubble can be determined by overlaying the two isotherms. TO and EPC are both surface active so in a mixed TO/EPC monolayer both molecules will be exposed to water. Since TO is less surface active than EPC, as Π increases the TO is progressively ejected. To understand the Π/area isotherm of EPC on a TO bubble, a variety of TO-EPC mixtures were spread at the air-water interface. The isotherms show an abrupt break in the curve caused by the ejection of TO from the monolayer into a new bulk phase. By overlaying the compression isotherm above the ejection point with a TO bubble compression isotherm, Γ can be estimated. This allows determination of Γ of EPC on a TO bubble as a function of Π. PMID:20151713

Adsorption of egg phosphatidylcholine to an air/water and triolein/water bubble interface: use of the 2-dimensional phase rule to estimate the surface composition of a phospholipid/triolein/water surface as a function of surface pressure.

PubMed

Mitsche, Matthew A; Wang, Libo; Small, Donald M

2010-03-11

Phospholipid monolayers play a critical role in the structure and stabilization of biological interfaces, including all membranes, the alveoli of the lungs, fat droplets in adipose tissue, and lipoproteins. The behavior of phospholipids in bilayers and at an air-water interface is well understood. However, the study of phospholipids at oil-water interfaces is limited due to technical challenges. In this study, egg phosphatidylcholine (EPC) was deposited from small unilamellar vesicles onto a bubble of either air or triolein (TO) formed in a low-salt buffer. The surface tension (gamma) was measured using a drop tensiometer. We observed that EPC binds irreversibly to both interfaces and at equilibrium exerts approximately 12 and 15 mN/m of pressure (Pi) at an air and TO interface, respectively. After EPC was bound to the interface, the unbound EPC was washed out of the cuvette, and the surface was compressed to study the Pi/area relationship. To determine the surface concentration (Gamma), which cannot be measured directly, compression isotherms from a Langmuir trough and drop tensiometer were compared. The air-water interfaces had identical characteristics using both techniques; thus, Gamma on the bubble can be determined by overlaying the two isotherms. Both TO and EPC are surface-active, so in a mixed TO/EPC monolayer, both molecules will be exposed to water. Since TO is less surface-active than EPC, as Pi increases, the TO is progressively ejected. To understand the Pi/area isotherm of EPC on a TO bubble, a variety of TO-EPC mixtures were spread at the air-water interface. The isotherms show an abrupt break in the curve caused by the ejection of TO from the monolayer into a new bulk phase. By overlaying the compression isotherm above the ejection point with a TO bubble compression isotherm, Gamma can be estimated. This allows determination of Gamma of EPC on a TO bubble as a function of Pi.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeon, Sangmin; Desikan, Ramya; Thundat, Thomas George

Young's equation, which is commonly used for determining the contact angle of liquid drops on a solid surface, ignores the vertical component of the surface energy. Although this force is extremely small and its effect on the solid can be ignored, it plays a significant role for flexible surfaces such as microcantilevers. A gold-coated silicon microcantilever and a dodecanethiol coated silicon microcantilever were used to detect real-time formation of nanobubbles on their surfaces when exposed to air-rich water. As air nanobubbles form on the surfaces of the cantilever, the cantilever undergoes bending, and we relate this to the vertical componentmore » of surface energy in Young's equation. This implies that the vertical component of the surface tension should be considered for flexible solid surfaces, and the formation of nanobubbles should be avoided when cantilevers are used as sensors to avoid artifacts.« less

Improving the Performance of Temperature Index Snowmelt Model of SWAT by Using MODIS Land Surface Temperature Data

PubMed Central

Yang, Yan; Onishi, Takeo; Hiramatsu, Ken

2014-01-01

Simulation results of the widely used temperature index snowmelt model are greatly influenced by input air temperature data. Spatially sparse air temperature data remain the main factor inducing uncertainties and errors in that model, which limits its applications. Thus, to solve this problem, we created new air temperature data using linear regression relationships that can be formulated based on MODIS land surface temperature data. The Soil Water Assessment Tool model, which includes an improved temperature index snowmelt module, was chosen to test the newly created data. By evaluating simulation performance for daily snowmelt in three test basins of the Amur River, performance of the newly created data was assessed. The coefficient of determination (R 2) and Nash-Sutcliffe efficiency (NSE) were used for evaluation. The results indicate that MODIS land surface temperature data can be used as a new source for air temperature data creation. This will improve snow simulation using the temperature index model in an area with sparse air temperature observations. PMID:25165746

An experimental study of a plunging liquid jet induced air carryunder and dispersion

NASA Astrophysics Data System (ADS)

Bonetto, F.; Drew, D. A.; Lahey, R. T., Jr.

1993-03-01

A good understanding of the air carryunder and bubble dispersion process associated with a plunging liquid jet is vital if one is to be able to quantify such diverse phenomena as sea surface chemistry, the meteorological significance of breaking ocean waves (e.g., mitigation of the greenhouse effect due to the absorption of CO2 by the oceans), the performance of certain type of chemical reactors, and a number of other important maritime-related applications. The absorption of greenhouse gases into the ocean has been hypothesized to be highly dependent upon the air carryunder that occurs due to breaking waves. This process can be approximated with a plunging liquid jet. Moreover, the air entrainment process due to the breaking bow waves of surface ships may cause long (i.e., up to 5 km in length) wakes. Naturally, easily detectable wakes are undesirable for naval warships. In addition, the air carryunder that occurs at most hydraulic structures in rivers is primarily responsible for the large air/water mass transfer that is associated with these structures. Also, air entrainment plays an important role in the slug flow regime. In particular, the liquid film surrounding a Taylor bubble has a flow in the opposite direction from the Taylor bubble. This liquid film can be thought of as a plunging liquid jet that produces a surface depression in the rear part of the Taylor bubble.

The origin of high electrolyte-electrode interfacial resistances in lithium cells containing garnet type solid electrolytes.

PubMed

Cheng, Lei; Crumlin, Ethan J; Chen, Wei; Qiao, Ruimin; Hou, Huaming; Franz Lux, Simon; Zorba, Vassilia; Russo, Richard; Kostecki, Robert; Liu, Zhi; Persson, Kristin; Yang, Wanli; Cabana, Jordi; Richardson, Thomas; Chen, Guoying; Doeff, Marca

2014-09-14

Dense LLZO (Al-substituted Li7La3Zr2O12) pellets were processed in controlled atmospheres to investigate the relationships between the surface chemistry and interfacial behavior in lithium cells. Laser induced breakdown spectroscopy (LIBS), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, synchrotron X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (XAS) studies revealed that Li2CO3 was formed on the surface when LLZO pellets were exposed to air. The distribution and thickness of the Li2CO3 layer were estimated by a combination of bulk and surface sensitive techniques with various probing depths. First-principles thermodynamic calculations confirmed that LLZO has an energetic preference to form Li2CO3 in air. Exposure to air and the subsequent formation of Li2CO3 at the LLZO surface is the source of the high interfacial impedances observed in cells with lithium electrodes. Surface polishing can effectively remove Li2CO3 and dramatically improve the interfacial properties. Polished samples in lithium cells had an area specific resistance (ASR) of only 109 Ω cm(2) for the LLZO/Li interface, the lowest reported value for Al-substituted LLZO. Galvanostatic cycling results obtained from lithium symmetrical cells also suggest that the quality of the LLZO/lithium interface has a significant impact on the device lifetime.

40 CFR 265.1090 - Recordkeeping requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... DISPOSAL FACILITIES Air Emission Standards for Tanks, Surface Impoundments, and Containers § 265.1090... containers using Container Level 3 air emission controls in accordance with the requirements of § 265.1087 of... section when the tank, surface impoundment, or container is or would be operating at capacity or the...

40 CFR 265.1090 - Recordkeeping requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... DISPOSAL FACILITIES Air Emission Standards for Tanks, Surface Impoundments, and Containers § 265.1090... containers using Container Level 3 air emission controls in accordance with the requirements of § 265.1087 of... section when the tank, surface impoundment, or container is or would be operating at capacity or the...

Fritzsche AAF, Fort Ord, Salinas, California. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1972-02-17

OBSERVATIONS) 93217 FORT u-;v %.’,Ll/r i%. A s .-7 _ -_ STATION STATION MARC YEARS NORTH CLASS MOURS (L S.T.) CONITIONU PEDI MEAN (KNS) 1 -3 4 6 7 10...m .. . . . ’S - ,S: -’.. _ _ { MOM "" S USAF ETAC PSYCHROMETRIC SUMMARY AIR WEATHER SER,/XCc’/’. STATION STATION NAME YIEARS MONTH ) [PAGE 1 2100

Initiation of the Worthington jet on the droplet impact

NASA Astrophysics Data System (ADS)

Yamamoto, Ken; Motosuke, Masahiro; Ogata, Satoshi

2018-02-01

The deformation of liquid droplets upon impact induces Worthington jets for a certain range of impact velocities. Although the growth of such a jet and its tip velocity are predicted from cases similar to droplet impact, the mechanism behind jet formation is yet to be understood. The present study uses high-speed visualization of droplet impact on a superhydrophobic surface to understand jet initiation in terms of the collapse of an air cavity. Water droplets with diameters of 2.0 and 3.0 mm are generated with the droplet Weber number varying from 2 to 20. The jet velocity is measured from the captured images, from which the maximum velocity is found to be We ˜ 7. The jet velocity at We ˜ 7 is approximately 15 times greater than the impact velocity. Moreover, surface waves are generated upon impact with the solid surface, and they induce an oscillation of the droplet cap as they propagate from the solid-liquid contact line to the top portion of the droplet. Furthermore, we find that the phase of the oscillation is related to the Weber number and greatly influences the jet velocity because it determines the initial conditions for jet generation.

Is Superhydrophobicity Equal to Underwater Superaerophilicity: Regulating the Gas Behavior on Superaerophilic Surface via Hydrophilic Defects.

PubMed

Cao, Moyuan; Li, Zhe; Ma, Hongyu; Geng, Hui; Yu, Cunming; Jiang, Lei

2018-06-20

Superhydrophobic surfaces have long been considered as superaerophilic surfaces while being placed in the aqueous environment. However, versatile gas/solid interacting phenomena were reported by utilizing different superhydrophobic substrates, indicating that these two wetting states cannot be simply equated. Herein, we demonstrate how the hydrophilic defects on the superhydrophobic track manipulate the underwater gas delivery, without deteriorating the water repellency of the surface in air. The versatile gas-transporting processes can be achieved on the defected superhydrophobic surfaces; on the contrary, in air, a water droplet is able to roll on those surfaces indistinguishably. Results show that the different media pressures applied on the two wetting states determine the diversified fluid-delivering phenomena; that is, the pressure-induced hydrophilic defects act as a gas barrier to regulate the bubble motion behavior under water. Through the rational incorporation of hydrophilic defects, a series of gas-transporting behaviors are achieved purposively, for example, gas film delivery, bubble transporting, and anisotropic bubble gating, which proves the feasibility of this underwater air-controlling strategy.

The Effect on Airplane Performance of the Factors That Must Be Considered in Applying Low-Drag Cowling to Radial Engines

NASA Technical Reports Server (NTRS)

Mcavoy, William H; Schey, Oscar W; Young, Alfred W

1933-01-01

This report presents the results of flight tests with three different airplanes using several types of low-drag cowling for radial air-cooled engines. The greater part of the tests were made with a Curtiss XF7Cc-1 (Sea Hawk) with a 410 horsepower. Wasp engine, using three fuselage nose shapes and six types of outer cowling. The six cowlings were: a narrow ring, a wide ring, a wide cowling similar in the original NACA cowling, a thick ring incorporating an exhaust collector, a single-surface cowling shaped like the outer surface of the exhaust-collector cowling, and polygon-ring cowling, of which the angle of the straight sections with the thrust line could be varied over a wide range.

The adsorption properties of short chain alcohols and Triton X-100 mixtures at the water-air interface.

PubMed

Zdziennicka, Anna

2009-07-15

The adsorption behaviour at the water-air interface of aqueous solutions of Triton X-100 and methanol (ethanol) mixtures at constant Triton X-100 (TX-100) concentration equal to 10(-7), 10(-6), 10(-5), 10(-4), 6x10(-4) and 10(-3)M, respectively, in a wide range of alcohol concentration was investigated by surface tension measurements of solutions. The obtained values of the surface tension of aqueous solutions of "pure" methanol and ethanol and their mixtures with TX-100, as well as the values of propanol solutions and their mixtures with TX-100 as a function of alcohol concentration taken from the literature were compared with those calculated from the Szyszkowski, Connors and Fainerman and Miller equations. On the basis of this comparison it was stated that these equations can be useful for description of the solution surface tension in the wide range of alcohol concentration, but only at the concentrations of Triton X-100 corresponding to its unsaturated layer in the absence of alcohol. It was also stated that the Connors equation is more adequate for concentrated aqueous organic solutions. The measured values of the surface tension were used in the Gibbs equation to determine the surface excess concentration of Triton X-100 and alcohol. Next, on the basis of Gibbs adsorption isotherms those of Guggenheim and Adam and real adsorption isotherms were established. From the obtained adsorption isotherms it results that alcohol influences the shape of TX-100 isotherms in the whole range of alcohol and TX-100 concentration, but TX-100 influences the alcohol isotherms only at TX-100 concentration at which the saturated monolayer at the solution-air interface is formed in the absence of alcohol. This conclusion was confirmed by analysis of the composition of the surface layer in comparison to the composition of the bulk phase in the equilibrium state.

A comparative study on laser induced shock cleaning of radioactive contaminants in air and water

NASA Astrophysics Data System (ADS)

Kumar, Aniruddha; Prasad, Manisha; Bhatt, R. B.; Behere, P. G.; Biswas, D. J.

2018-03-01

Efficient removal of Uranium-di-oxide (UO2) particulates from stainless steel surface was effected by Nd-YAG laser induced plasma shock waves in air as well as in water environment. The propagation velocity of the generated shock wave was measured by employing the photo-acoustic probe deflection method. Monitoring of the alpha activity of the sample with a ZnS (Ag) scintillation detector before and after the laser exposure allowed the estimation of decontamination efficiency defined as the percentage removal of the initial activity. Experiments were carried out to study the effect of laser pulse energy, number of laser exposures, orientation of the sample, the separation between the substrate surface and the onset point of the shock wave on the de-contamination efficiency. The most optimised cleaning was found to occur when the laser beam impinged normally on the sample that was immersed in water and placed at a distance of ∼0.7 mm from the laser focal spot. Analysis of the cleaned surface by optical microscopes established that laser induced shock cleaning in no way altered the surface property. The shock force generated in both air and water has been estimated theoretically and has been found to exceed the Van der Waal's binding force for spherical contaminant particulate.

Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4))

PubMed Central

Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

2010-01-01

In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air. Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b. PMID:20941336

Self assembled molecular monolayers on high surface area materials as molecular getters

DOEpatents

King, David E.; Herdt, Gregory C.; Czanderna, Alvin W.

1997-01-01

The present invention relates to a gettering material that may be used as a filtration medium to remove pollutants from the environment. The gettering material comprises a high surface area material having a metal surface that chemically bonds n-alkanethiols in an organized manner thereby forming a molecular monolayer over the metal surface. The n-alkanethiols have a free functional group that interacts with the environment thereby binding specific pollutants that may be present. The gettering material may be exposed to streams of air in heating, ventilation, and air conditioning systems or streams of water to remove specific pollutants from either medium.

Self assembled molecular monolayers on high surface area materials as molecular getters

DOEpatents

King, D.E.; Herdt, G.C.; Czanderna, A.W.

1997-01-07

The present invention relates to a gettering material that may be used as a filtration medium to remove pollutants from the environment. The gettering material comprises a high surface area material having a metal surface that chemically bonds n-alkanethiols in an organized manner thereby forming a molecular monolayer over the metal surface. The n-alkanethiols have a free functional group that interacts with the environment thereby binding specific pollutants that may be present. The gettering material may be exposed to streams of air in heating, ventilation, and air conditioning systems or streams of water to remove specific pollutants from either medium. 9 figs.

Predicting gravity and sediment thickness in Afghanistan

NASA Astrophysics Data System (ADS)

Jung, W.; Brozena, J.; Peters, M.

2013-02-01

The US Naval Research Laboratory conducted comprehensive high-altitude (7 km above mean sea level) aero-geophysical surveys over Afghanistan in 2006 (Rampant Lion I). The surveys were done in collaboration with the US Geological Survey and upon the request of Islamic Republic of Afghanistan Ministry of Mines. In this study, we show that a best fitting admittance between topography and airborne gravity in western Afghanistan can be used to predict airborne gravity for the no-data area of eastern Afghanistan where the mountains are too high to conduct airborne surveys, due to the threat of ground fire. The differences between the airborne and the predicted gravity along a tie-track through the no-data area were found to be within ±12 mGal range with rms difference 7.3 mGal, while those between the predicted gravity from a simple Airy model (with compensation depth of 32 km and crustal density of 2.67 g cm-3) and the airborne gravity were within ±22 mGal range with rms difference 10.3 mGal. A combined airborne free-air anomaly has been constructed by merging the predicted gravity with the airborne data. We also demonstrate that sediment thickness can be estimated for basin areas where surface topography and airborne free-air anomaly profiles do not show a correlation presumably because of thick sediments. In order to estimate sediment thickness, we first determine a simple linear relationship from a scatter plot of the airborne gravity points and the interpolated Shuttle Radar Topography Mission (SRTM) topography along the Rampant Lion I tracks, and computed corresponding quasi-topography tracks by multiplying the linear relationship with the airborne free-air anomalies. We then take the differences between the SRTM and quasi-topography as a first-order estimate of sediment thickness. A global gravity model (GOCO02S), upward continued to the same altitude (7 km above mean sea level) as the data collection, was compared with the low-pass filtered (with cutoff wavelength 132 km which is approximately equivalent to the reported safe degree and order 250 of GOCO02S at 34º N) combined airborne free-air anomalies. The rms difference between the two data sets was 12.4 mGal. The observed admittance in the western Afghanistan mountains appears to be best fit to a theoretical elastic plate compensation model (with an effective elastic thickness of 5 km and crustal thickness of 22 km) where the ratio between surface load and subsurface load is equal.

3-D Surface Depression Profiling Using High Frequency Focused Air-Coupled Ultrasonic Pulses

NASA Technical Reports Server (NTRS)

Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.

1999-01-01

Surface topography is an important variable in the performance of many industrial components and is normally measured with diamond-tip profilometry over a small area or using optical scattering methods for larger area measurement. This article shows quantitative surface topography profiles as obtained using only high-frequency focused air-coupled ultrasonic pulses. The profiles were obtained using a profiling system developed by NASA Glenn Research Center and Sonix, Inc (via a formal cooperative agreement). (The air transducers are available as off-the-shelf items from several companies.) The method is simple and reproducible because it relies mainly on knowledge and constancy of the sound velocity through the air. The air transducer is scanned across the surface and sends pulses to the sample surface where they are reflected back from the surface along the same path as the incident wave. Time-of-flight images of the sample surface are acquired and converted to depth/surface profile images using the simple relation (d = V*t/2) between distance (d), time-of-flight (t), and the velocity of sound in air (V). The system has the ability to resolve surface depression variations as small as 25 microns, is useable over a 1.4 mm vertical depth range, and can profile large areas only limited by the scan limits of the particular ultrasonic system. (Best-case depth resolution is 0.25 microns which may be achievable with improved isolation from vibration and air currents.) The method using an optimized configuration is reasonably rapid and has all quantitative analysis facilities on-line including 2-D and 3-D visualization capability, extreme value filtering (for faulty data), and leveling capability. Air-coupled surface profilometry is applicable to plate-like and curved samples. In this article, results are shown for several proof-of-concept samples, plastic samples burned in microgravity on the STS-54 space shuttle mission, and a partially-coated cylindrical ceramic composite sample. Impressive results were obtained for all samples when compared with diamond-tip profiles and measurements from micrometers. The method is completely nondestructive, noninvasive, non-contact and does not require light-reflective surfaces.

Monte Carlo simulations in CT for the study of the surface air kerma and energy imparted to phantoms of varying size and position

NASA Astrophysics Data System (ADS)

Avilés Lucas, P.; Dance, D. R.; Castellano, I. A.; Vañó, E.

2004-04-01

A Monte Carlo computational model of CT has been developed and used to investigate the effect of various physical factors on the surface air kerma length product, the peak surface air kerma, the air kerma length product within a phantom and the energy imparted. The factors investigated were the bow-tie filter and the size, shape and position of a phantom which simulates the patient. The calculations show that the surface air kerma length product and the maximum surface air kerma are mainly dependent on phantom position and decrease along the vertical axis of the CT plane as the phantom surface moves away from the isocentre along this axis. As a result, measurements using standard body dosimetry phantoms may underestimate the skin dose for real patients. This result is specially important for CT fluoroscopic procedures: for an adult patient the peak skin dose can be 37% higher than that estimated with a standard measurement on the body AAPM (American Association of Physicists in Medicine) phantom. The results also show that the energy imparted to a phantom is mainly influenced by phantom size and is nearly independent of phantom position (within 3%) and shape (up to 5% variation). However, variations of up to 30% were found for the air kerma to regions within the AAPM body phantom when it is moved vertically. This highlights the importance of calculating doses to organs taking into account their size and position within the gantry.

Spatial and Temporal Inter-Relationships between Anomalies and Trends of Temperature, Moisture, Cloud Cover, and OLR as Observed by AIRS/AMSU on Aqua

NASA Technical Reports Server (NTRS)

Susskind, Joel

2008-01-01

AIRS/AMSU is the advanced IR/MW atmospheric sounding system launched on EOS Aqua in May 2002. Products derived from AIRS/AMSU by the AIRS Science Team include surface skin temperature and atmospheric temperature profiles; atmospheric humidity profiles, fractional cloud cover and cloud top pressure, and OLR. Products covering the period September 2002 through the present have been derived from AIRS/AMSU using the AIRS Science Team Version 5 retrieval algorithm. In this paper, we will show results covering the time period September 2006 - November 2008. This time period is marked by a substantial warming trend of Northern Hemisphere Extratropical land surface skin temperatures, as well as pronounced El Nino - La Nina episodes. These both influence the spatial and temporal anomaly patterns of atmospheric temperature and moisture profiles, as well as of cloud cover and Clear sky and All Sky OLR. The relationships between temporal and spatial anomalies of these parameters over this time period, as determined from AIRS/AMSU observations, will be shown, with particular emphasis on which contribute significantly to OLR anomalies in each of the tropics and extra-tropics. Results will also be shown to validate the anomalies and trends of temperature profiles and OLR as determined from analysis of AIRS/AMSU data. Global and regional trends during the 6 1/3 year period are not necessarily indicative of what has happened in the past, or what may happen in the future. Nevertheless, the inter-relationships of spatial and temporal anomalies of atmospheric geophysical parameters with those of surface skin temperature are indicative of climate processes, and can be used to test the performance of climate models when driven by changes in surface temperatures.

Spatial and Temporal Inter-Relationship between Anomalies and Trends of Temperature, Moisture, Cloud Cover and OLR as Observed by AIRS/AMSU on Aqua

NASA Technical Reports Server (NTRS)

Susskind, Joel; Molnar, Gyula

2009-01-01

AIRS/AMSU is the advanced IR/MW atmospheric sounding system launched on EOS Aqua in May 2002. Products derived from AIRS/AMSU by the AIRS Science Team include surface skin temperature and atmospheric temperature profiled; atmospheric humidity profiles, fractional cloud clover and cloud top pressure, and OLR. Products covering the period September 2002 through the present have been derived from AIRS/AMSU using the AIRS Science Team Version 5 retrieval algorithm. In this paper, we will show results covering the time period September 2006 - November 2008. This time period is marked by a substantial warming trend of Northern Hemisphere Extra-tropical land surface skin temperatures, as well as pronounced El Nino - La Nina episodes. These both influence the spatial and temporal anomaly patterns of atmospheric temperature and moisture profiles, as well as of cloud cover and Clear Sky and All Sky OLR. The relationships between temporal and spatial anomalies of these parameters over this time period, as determined from AIRS/AMSU observations, will be shown with particular emphasis on which contribute significantly to OLR anomalies in each of the tropics and extra-tropics. Results will also be shown to evaluate the anomalies and trends of temperature profiles and OLR as determined from analysis of AIRS/AMSU data. Global and regional trends during the 6 1/3 year time period are not necessarily indicative of what has happened in the past, or what may happen in the future. Nevertheless, the inter-relationships of spatial and temporal anomalies of atmospheric geophysical parameters with those of surface skin temperature are indicative of climate processes, and can be used to test the performance of climate models when driven by changes in surface temperatures.

Friction and Wear Properties of As-deposited and Carbon Ion-implanted Diamond Films

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1994-01-01

Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 ke V ion energy, resulting in a dose of 1.2310(exp 17) carbon ions/cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40 percent relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and were properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to 10(exp -8)mm(exp 3)/N-m) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4)mm(exp 3/N-m) in ultrahigh vacuum. The carbon ion implanation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, nondiamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine- and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7)mm(exp 3/N-m). Even in ultrahigh vacuum, the presence of the nondiamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6)mm(exp 3)/N-m. Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum. The wear mechanism of diamond films is that of small fragments chipping off the surface. The size of wear particles is related to the extent of wear rates.

Characteristics of surface ozone and nitrogen oxides at urban, suburban and rural sites in Ningbo, China

NASA Astrophysics Data System (ADS)

Tong, Lei; Zhang, Huiling; Yu, Jie; He, Mengmeng; Xu, Nengbin; Zhang, Jingjing; Qian, Feizhong; Feng, Jiayong; Xiao, Hang

2017-05-01

Surface ozone (O3) is a harmful air pollutant that has attracted growing concern in China. In this study, the mixing ratios of O3 and nitrogen oxides (NOx) at three different sites (urban, suburban and rural) of Ningbo were continuously measured to investigate the spatiotemporal characteristics of O3 and its relationships with environmental variables. The diurnal O3 variations were characterized by afternoon maxima (38.7-53.1 ppb on annual average) and early morning minima (11.7-26.2 ppb) at all the three sites. Two seasonal peaks of O3 were observed in spring (April or May) and autumn (October) with minima being observed in winter (December). NOx levels showed generally opposite variations to that of O3 with diurnal and seasonal maxima occurring in morning/evening rush-hours and in winter, respectively. As to the inter-annual variations of air pollutants, generally decreasing and increasing trends were observed in NO and O3 levels, respectively, from 2012 to 2015 at both urban and suburban sites. O3 levels were positively correlated with temperature but negatively correlated with relative humidity and NOx levels. Significant differences in O3 levels were observed for different wind speeds and wind directions (p < 0.001). O3 levels varied non-linearly with wind speed ranges with an increasing trend within 4 m/s. Higher mixing ratio of O3 was observed for wind blowing from the sea, which indicates that the coastal air mass might carry more O3. A decreasing trend in O3 levels was observed from weekdays to weekends at all the three sites. As to the spatial variation, higher levels of O3 were observed at the suburban and rural sites where less O3 was depleted by NO titration. In contrast, the urban site exhibited lower O3 but higher NOx levels due to the influence of traffic emissions. Larger amplitudes of diurnal and monthly O3 variations were observed at the suburban site than those at the urban and rural sites. In general, the O3 levels at the non-urban sites were more affected by the background transport, while both the local and regional contributions played roles in urban O3 variations. The annual average O3 mixing ratios (22.7-37.7 ppb) in Ningbo were generally similar to those of other regions around the world. However, the recommended air quality standards for O3 were often exceeded during warm seasons, which could be a potential threat to both local population and plant growth.

Role of air-water interfaces in colloid transport in porous media: A review

NASA Astrophysics Data System (ADS)

Flury, Markus; Aramrak, Surachet

2017-07-01

Air-water interfaces play an important role in unsaturated porous media, giving rise to phenomena like capillarity. Less recognized and understood are interactions of colloids with the air-water interface in porous media and the implications of these interactions for fate and transport of colloids. In this review, we discuss how colloids, both suspended in the aqueous phase and attached at pore walls, interact with air-water interfaces in porous media. We discuss the theory of colloid/air-water interface interactions, based on the different forces acting between colloids and the air-water interface (DLVO, hydrophobic, capillary forces) and based on thermodynamic considerations (Gibbs free energy). Subsurface colloids are usually electrostatically repelled from the air-water interface because most subsurface colloids and the air-water are negatively charged. However, hydrophobic interactions can lead to attraction to the air-water interface. When colloids are at the air-water interface, capillary forces are usually dominant over other forces. Moving air-water interfaces are effective in mobilizing and transporting colloids from surfaces. Thermodynamic considerations show that, for a colloid, the air-water interface is the favored state as compared with the suspension phase, except for hydrophilic colloids in the nanometer size range. Experimental evidence indicates that colloid mobilization in soils often occurs through macropores, although matrix transport is also prevalent in absence of macropores. Moving air-water interfaces, e.g., occurring during infiltration, imbibition, or drainage, have been shown to scour colloids from surfaces and translocate colloids. Colloids can also be pinned to surfaces by thin water films and capillary menisci at the air-water-solid interface line, causing colloid retention and immobilization. Air-water interfaces thus can both mobilize or immobilize colloids in porous media, depending on hydrodynamics and colloid and surface chemistry.

Endosulfan in China 2-emissions and residues.

PubMed

Jia, Hongliang; Sun, Yeqing; Li, Yi-Fan; Tian, Chongguo; Wang, Degao; Yang, Meng; Ding, Yongshen; Ma, Jianmin

2009-05-01

Endosulfan is one of the organochlorine pesticides (OCPs) and also a candidate to be included in a group of new persistent organic pollutants (UNEP 2007). The first national endosulfan usage inventories in China with 1/4 degrees longitude by 1/6 degrees latitude resolution has been reported in an accompanying paper. In the second part of the paper, we compiled the gridded historical emissions and soil residues of endosulfan in China from the usage inventories. Based on the residue/emission data, gridded concentrations of endosulfan in Chinese soil and air have been calculated. These inventories will provide valuable data for the further study of endosulfan. Emission and residue of endosulfan were calculated from endosulfan usage by using a simplified gridded pesticide emission and residue model-SGPERM, which is an integrated modeling system combining mathematical model, database management system, and geographic information system. By using the emission and residue inventories, annual air and soil concentrations of endosulfan in each cell were determined. Historical gridded emission and residue inventories of alpha- and beta-endosulfan in agricultural soil in China with 1/4 degrees longitude by 1/6 degrees latitude resolution have been created. Total emissions were around 10,800 t, with alpha-endosulfan at 7,400 t and beta-endosulfan at 3,400 t from 1994 to 2004. The highest residues were 140 t for alpha-endosulfan and 390 t for beta-endosulfan, and the lowest residues were 0.7 t for alpha-endosulfan and 170 t for beta-endosulfan in 2004 in Chinese agricultural soil where endosulfan was applied. Based on the emission and residue inventories, concentrations of alpha- and beta-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell. We have estimated annual averaged air concentrations and the annual minimum and maximum soil concentrations across China. The real concentrations will be different from season to season. Although our model does not consider the transport of the insecticide in the atmosphere, which could be very important in some areas during some special time, the estimated concentrations of endosulfan in Chinese air and soil derived from the endosulfan emission and residue inventories are in general consistent with the published monitoring data. To our knowledge, this work is the first inventory of this kind for endosulfan published on a national scale. Concentrations of the chemical in Chinese air and agricultural surface soil were calculated for each grid cell. Results show that the estimated concentrations of endosulfan in Chinese air and soil agree reasonably well with the monitoring data in general. The gridded endosulfan emission/residue inventories and also the air and soil concentration inventories created in this study will be updated upon availability of new information, including usage and monitoring data. The establishment of these inventories for the OCP is important for both scientific communities and policy makers.

Coupled retrieval of aerosol properties and land surface reflection using the Airborne Multiangle SpectroPolarimetric Imager

NASA Astrophysics Data System (ADS)

Xu, Feng; van Harten, Gerard; Diner, David J.; Kalashnikova, Olga V.; Seidel, Felix C.; Bruegge, Carol J.; Dubovik, Oleg

2017-07-01

The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) has been flying aboard the NASA ER-2 high-altitude aircraft since October 2010. In step-and-stare operation mode, AirMSPI acquires radiance and polarization data in bands centered at 355, 380, 445, 470*, 555, 660*, 865*, and 935 nm (* denotes polarimetric bands). The imaged area covers about 10 km by 11 km and is typically observed from nine viewing angles between ±66° off nadir. For a simultaneous retrieval of aerosol properties and surface reflection using AirMSPI, an efficient and flexible retrieval algorithm has been developed. It imposes multiple types of physical constraints on spectral and spatial variations of aerosol properties as well as spectral and temporal variations of surface reflection. Retrieval uncertainty is formulated by accounting for both instrumental errors and physical constraints. A hybrid Markov-chain/adding-doubling radiative transfer (RT) model is developed to combine the computational strengths of these two methods in modeling polarized RT in vertically inhomogeneous and homogeneous media, respectively. Our retrieval approach is tested using 27 AirMSPI data sets with low to moderately high aerosol loadings, acquired during four NASA field campaigns plus one AirMSPI preengineering test flight. The retrieval results including aerosol optical depth, single-scattering albedo, aerosol size and refractive index are compared with Aerosol Robotic Network reference data. We identify the best angular combinations for 2, 3, 5, and 7 angle observations from the retrieval quality assessment of various angular combinations. We also explore the benefits of polarimetric and multiangular measurements and target revisits in constraining aerosol property and surface reflection retrieval.

Migration of Beryllium via Multiple Exposure Pathways among Work Processes in Four Different Facilities

PubMed Central

Armstrong, Jenna L.; Day, Gregory A.; Park, Ji Young; Stefaniak, Aleksandr B.; Stanton, Marcia L.; Deubner, David C.; Kent, Michael S.; Schuler, Christine R.; Virji, M. Abbas

2016-01-01

Inhalation of beryllium is associated with the development of sensitization; however, dermal exposure may also be important. The primary aim of this study was to elucidate relationships among exposure pathways in four different manufacturing and finishing facilities. Secondary aims were to identify jobs with increased levels of beryllium in air, on skin, and on surfaces; identify potential discrepancies in exposure pathways, and determine if these are related to jobs with previously identified risk. Beryllium was measured in air, on cotton gloves, and on work surfaces. Summary statistics were calculated and correlations among all three measurement types were examined at the facility and job level. Exposure ranking strategies were used to identify jobs with higher exposures. The highest air, glove, and surface measurements were observed in beryllium metal production and beryllium oxide ceramics manufacturing jobs that involved hot processes and handling powders. Two finishing and distribution facilities that handle solid alloy products had lower exposures than the primary production facilities, and there were differences observed among jobs. For all facilities combined, strong correlations were found between air-surface (rp ≥ 0.77), glove-surface (rp ≥ 0.76), and air-glove measurements (rp ≥ 0.69). In jobs where higher risk of beryllium sensitization or disease has been reported, exposure levels for all three measurement types were higher than in jobs with lower risk, though they were not the highest. Some jobs with low air concentrations had higher levels of beryllium on glove and surface wipe samples, suggesting a need to further evaluate the causes of the discrepant levels. Although such correlations provide insight on where beryllium is located throughout the workplace, they cannot identify the direction of the pathways between air, surface, or skin. Ranking strategies helped to identify jobs with the highest combined air, glove, and/or surface exposures. All previously identified high-risk jobs had high air concentrations, dermal mass loading, or both, and none had low dermal and air. We have found that both pathways are relevant. PMID:25357184

Is there an association between airborne and surface microbes in the critical care environment?

PubMed

Smith, J; Adams, C E; King, M F; Noakes, C J; Robertson, C; Dancer, S J

2018-04-09

There are few data and no accepted standards for air quality in the intensive care unit (ICU). Any relationship between airborne pathogens and hospital-acquired infection (HAI) risk in the ICU remains unknown. First, to correlate environmental contamination of air and surfaces in the ICU; second, to examine any association between environmental contamination and ICU-acquired staphylococcal infection. Patients, air, and surfaces were screened on 10 sampling days in a mechanically ventilated 10-bed ICU for a 10-month period. Near-patient hand-touch sites (N = 500) and air (N = 80) were screened for total colony count and Staphylococcus aureus. Air counts were compared with surface counts according to proposed standards for air and surface bioburden. Patients were monitored for ICU-acquired staphylococcal infection throughout. Overall, 235 of 500 (47%) surfaces failed the standard for aerobic counts (≤2.5 cfu/cm 2 ). Half of passive air samples (20/40: 50%) failed the 'index of microbial air' contamination (2 cfu/9 cm plate/h), and 15/40 (37.5%) active air samples failed the clean air standard (<10 cfu/m 3 ). Settle plate data were closer to the pass/fail proportion from surfaces and provided the best agreement between air parameters and surfaces when evaluating surface benchmark values of 0-20 cfu/cm 2 . The surface standard most likely to reflect hygiene pass/fail results compared with air was 5 cfu/cm 2 . Rates of ICU-acquired staphylococcal infection were associated with surface counts per bed during 72h encompassing sampling days (P = 0.012). Passive air sampling provides quantitative data analogous to that obtained from surfaces. Settle plates could serve as a proxy for routine environmental screening to determine the infection risk in ICU. Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Thickened boundary layer theory for air film drag reduction on a van body surface

NASA Astrophysics Data System (ADS)

Xie, Xiaopeng; Cao, Lifeng; Huang, Heng

2018-05-01

To elucidate drag reduction mechanism on a van body surface under air film condition, a thickened boundary layer theory was proposed and a frictional resistance calculation model of the van body surface was established. The frictional resistance on the van body surface was calculated with different parameters of air film thickness. In addition, the frictional resistance of the van body surface under the air film condition was analyzed by computational fluid dynamics (CFD) simulation and different air film states that influenced the friction resistance on the van body surface were discussed. As supported by the CFD simulation results, the thickened boundary layer theory may provide reference for practical application of air film drag reduction on a van body surface.

30 CFR 56.13011 - Air receiver tanks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Air receiver tanks. 56.13011 Section 56.13011... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13011 Air receiver tanks. Air receiver tanks shall be equipped with one or more automatic pressure...

30 CFR 56.13011 - Air receiver tanks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Air receiver tanks. 56.13011 Section 56.13011... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13011 Air receiver tanks. Air receiver tanks shall be equipped with one or more automatic pressure...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

30 CFR 56.13011 - Air receiver tanks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Air receiver tanks. 56.13011 Section 56.13011... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13011 Air receiver tanks. Air receiver tanks shall be equipped with one or more automatic pressure...

30 CFR 56.13011 - Air receiver tanks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13011 Air receiver tanks. Air receiver tanks shall be equipped with one or more automatic pressure... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air receiver tanks. 56.13011 Section 56.13011...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

Evaluating the Vertical Distribution of Ozone and its Relationship to Pollution Events in Air Quality Models using Satellite Data

NASA Astrophysics Data System (ADS)

Osterman, G. B.; Neu, J. L.; Eldering, A.; Pinder, R. W.; Tang, Y.; McQueen, J.

2014-12-01

Most regional scale models that are used for air quality forecasts and ozone source attribution do not adequately capture the distribution of ozone in the mid- and upper troposphere, but it is unclear how this shortcoming relates to their ability to simulate surface ozone. We combine ozone profile data from the NASA Earth Observing System (EOS) Tropospheric Emission Spectrometer (TES) and a new joint product from TES and the Ozone Monitoring Instrument along with ozonesonde measurements and EPA AirNow ground station ozone data to examine air quality events during August 2006 in the Community Multi-Scale Air Quality (CMAQ) and National Air Quality Forecast Capability (NAQFC) models. We present both aggregated statistics and case-study analyses with the goal of assessing the relationship between the models' ability to reproduce surface air quality events and their ability to capture the vertical distribution of ozone. We find that the models lack the mid-tropospheric ozone variability seen in TES and the ozonesonde data, and discuss the conditions under which this variability appears to be important for surface air quality.

Use of passive samplers and surrogate surfaces to investigate sources of mercury deposited to the western United States

NASA Astrophysics Data System (ADS)

Wright, G.; Gustin, M. S.; Weiss-Penzias, P. S.

2012-12-01

The Western Airborne Contaminants Assessment Project (WACAP) showed that fish in eight National Parks of the western U.S. had mercury(Hg) concentrations that exceeded the threshold for fish eating wildlife (www.nature.nps.gov/air/Studies/air_toxics/wacap.cfm). These observations led to the development of this study focused on investigating air gaseous oxidized mercury (GOM) concentrations and potential dry deposition using developed passive samplers and surrogate surfaces. The primary question was whether local, regional or global sources are responsible for the mercury measured in fish in these Western parks. To investigate this, passive samplers and surrogate surface samplers were deployed from the coast of California to the eastern edge of Nevada. Sampling sites were located from west to east at Point Reyes National Seashore, CA; Elkhorn Slough, CA, Lick Observatory, CA; Chews Ridge, CA; Chalk Mountain, CA; Yosemite National Park, CA; Sequoia & Kings Canyon National Park, CA; and Great Basin National Park, NV. Ancillary data (meteorology and ozone concentrations) collected by the parks will be applied to better understand potential sources. Air mercury concentrations were also measured at select locations using a Tekran® 2537a/1130mercury air measurement system for 4-6 weeks. Air GOM concentrations and potential deposition were measured simultaneously as a function of elevation at Yosemite and Great Basin National Park, using the passive samplers and surrogate surfaces during sampling intensives, allowing us to better understand potential sources of mercury to park ecosystems. Data collection began in August of 2010 and was completed in June 2012. Analyses of the data thus far has shown the lowest relative concentrations and potential GOM deposition were observed at the low elevation coastal sites, Elkhorn Slough and Point Reyes National Seashore. Highest values of potential deposition were recorded at Lick Observatory, a high elevation coastal site, while highest relative concentrations were measured at Great Basin National Park. Mean elemental mercury and GOM concentrations, collected using a Tekran® 2537A/1130 system, were 1.5 ± 0.6 ng/ m3 and 70 ± 50 pg/m3 respectively at Great Basin NP, 1.5 ng/m3 ¬± 0.3 and 6 pg/m3 ± 7 at Sequoia National Park, and 1.5 ng/m3 ± 1 and 14 pg/m3 ± 11 at Yosemite National Park.

Constraining the uncertainty in emissions over India with a regional air quality model evaluation

NASA Astrophysics Data System (ADS)

Karambelas, Alexandra; Holloway, Tracey; Kiesewetter, Gregor; Heyes, Chris

2018-02-01

To evaluate uncertainty in the spatial distribution of air emissions over India, we compare satellite and surface observations with simulations from the U.S. Environmental Protection Agency (EPA) Community Multi-Scale Air Quality (CMAQ) model. Seasonally representative simulations were completed for January, April, July, and October 2010 at 36 km × 36 km using anthropogenic emissions from the Greenhouse Gas-Air Pollution Interaction and Synergies (GAINS) model following version 5a of the Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants project (ECLIPSE v5a). We use both tropospheric columns from the Ozone Monitoring Instrument (OMI) and surface observations from the Central Pollution Control Board (CPCB) to closely examine modeled nitrogen dioxide (NO2) biases in urban and rural regions across India. Spatial average evaluation with satellite retrievals indicate a low bias in the modeled tropospheric column (-63.3%), which reflects broad low-biases in majority non-urban regions (-70.1% in rural areas) across the sub-continent to slightly lesser low biases reflected in semi-urban areas (-44.7%), with the threshold between semi-urban and rural defined as 400 people per km2. In contrast, modeled surface NO2 concentrations exhibit a slight high bias of +15.6% when compared to surface CPCB observations predominantly located in urban areas. Conversely, in examining extremely population dense urban regions with more than 5000 people per km2 (dense-urban), we find model overestimates in both the column (+57.8) and at the surface (+131.2%) compared to observations. Based on these results, we find that existing emission fields for India may overestimate urban emissions in densely populated regions and underestimate rural emissions. However, if we rely on model evaluation with predominantly urban surface observations from the CPCB, comparisons reflect model high biases, contradictory to the knowledge gained using satellite observations. Satellites thus serve as an important emissions and model evaluation metric where surface observations are lacking, such as rural India, and support improved emissions inventory development.

AirSWOT flights and field campaigns for the 2017 Arctic-Boreal Vulnerability Experiment (ABoVE)

NASA Astrophysics Data System (ADS)

Smith, L. C.; Pavelsky, T.; Lettenmaier, D. P.; Gleason, C. J.; Pietroniro, A.; Applejohn, A.; Arvesen, J. C.; Bjella, K.; Carter, T.; Chao, R.; Cooley, S. W.; Cooper, M. G.; Cretaux, J. F.; Douglass, T.; Faria, D.; Fayne, J.; Fiset, J. M.; Goodman, S.; Hanna, B.; Harlan, M.; Langhorst, T.; Marsh, P.; Moreira, D. M.; Minear, J. T.; Onclin, C.; Overstreet, B. T.; Peters, D.; Pettit, J.; Pitcher, L. H.; Russell, M.; Spence, C.; Topp, S.; Turner, K. W.; Vimal, S.; Wilcox, E.; Woodward, J.; Yang, D.; Zaino, A.

2017-12-01

Some 50% of Canada and 80% of Alaska is thought to be underlain by permafrost, influencing the hydrology, ecology and carbon cycles of Arctic-Boreal landscapes. This influence includes enhanced presence of millions of lakes and wetlands, which release trace gases while supporting critical ecosystems and traditional subsistence economies. Permafrost is challenging to infer from remote sensing and difficult to sample in the field. A series of 2017 AirSWOT flights flown for the NASA Arctic-Boreal Vulnerability Experiment (ABoVE) will study whether small variations in water surface elevations (WSEs) of Arctic-Boreal lakes are sensitive to presence and/or disturbance of permafrost. AirSWOT is an experimental NASA airborne radar designed to map WSE and a precursor to SWOT, a forthcoming NASA/CNES/CSA satellite mission to map WSE globally with launch in 2021. The ABoVE AirSWOT flight experiments adopted long flight lines of the broader ABoVE effort to traverse broad spatial gradients of permafrost, climate, ecology, and geology. AirSWOT acquisitions consisted of long (1000s of kilometers) strips of Ka-band interferometric radar imagery, and high resolution visible/NIR imagery and DEMs from a digital Cirrus CIR camera. Intensive AirSWOT mapping and ground-based GPS field surveys were conducted at 11 field sites for eight study areas of Canada and Alaska: 1) Saint-Denis, Redberry Lake, North Saskatchewan River (Saskatchewan); 2) Peace-Athabasca Delta (Alberta); 3) Slave River Delta (N.W.T.); 4) Canadian Shield (Yellowknife area, Daring Lake, N.W.T.); 5) Mackenzie River (Inuvik-Tuktoyaktuk corridor, N.W.T.); 6) Old Crow Flats (Yukon Territory); 7) Sagavanirktok River (Alaska); 8) Yukon Flats (Alaska). Extensive ground campaigns were conducted by U.S. and Canadian collaborators to collect high quality surveys of lake WSE, river WSE and discharge, and shoreline locations. Field experiments included traditional and novel GPS surveying methods, including custom-built GPS buoys that float or drift upon water surfaces. Other ABoVE flight packages flown along AirSWOT lines included LVIS, AVIRIS, UAVSAR and AirMOSS. Processing and integration of ABoVE remote sensing and field datasets may provide new scientific insights about the influence of permafrost on surface water hydrology, over broad spatial scales.

Gamma inert sterilization: a solution to polyethylene oxidation?

PubMed

Medel, Francisco J; Kurtz, Steven M; Hozack, William J; Parvizi, Javad; Purtill, James J; Sharkey, Peter F; MacDonald, Daniel; Kraay, Matthew J; Goldberg, Victor; Rimnac, Clare M

2009-04-01

In the 1990s, oxidation was found to occur in ultra-high molecular weight polyethylene total joint replacement components following gamma irradiation and prolonged shelf aging in air. Orthopaedic manufacturers developed barrier packaging to reduce oxidation during and after radiation sterilization. The present study explores the hypothesis that polyethylene components sterilized in a low-oxygen environment undergo similar in vivo oxidative mechanisms as inserts sterilized in air. In addition, the potential influence of the different sterilization processes on the wear performance of the polyethylene components was examined. An analysis of oxidation, wear, and surface damage was performed for forty-eight acetabular liners and 123 tibial inserts. The mean implantation time was 12.3+/-3.7 years for thirty-one acetabular liners that had been gamma sterilized in air and 4.0+/-2.5 years for the seventeen acetabular liners that had been gamma sterilized in inert gas. The mean implantation time was 11.0+/-3.2 years for the twenty-six tibial inserts that had been sterilized in air and 2.8+/-2.2 years for the ninety-seven tibial inserts that had been gamma sterilized in inert gas. Oxidation and hydroperoxide levels were characterized in loaded and unloaded regions of the inserts. Measurable oxidation and oxidation potential were observed in all cohorts. The oxidation and hydroperoxide levels were regional. Surfaces with access to body fluids were more heavily oxidized than protected bearing surfaces were. This variation appeared to be greater in historical (gamma-in-air-sterilized) components. Regarding wear performance, historical and conventional acetabular liners showed similar wear penetration rates, whereas a low incidence of delamination was confirmed for the conventional tibial inserts in the first decade of implantation. The present study explores the impact of industry-wide changes in sterilization practices for polyethylene. We found lower oxidation and oxidation potential in the conventional acetabular liners and tibial inserts that had been gamma sterilized in inert gas as compared with the historical components that had been gamma sterilized in air. However, we also found strong evidence that conventional components undergo mechanisms of in vivo oxidation similar to those observed following gamma irradiation in air. In addition, gamma sterilization in inert gas did not provide polyethylene with a significant improvement in terms of wear resistance as compared with gamma sterilization in air, except for a lower incidence of delamination in the first decade of implantation for tibial inserts.

Surface Ocean pCO2 Seasonality and Sea-Air CO2 Flux Estimates for the North American East Coast

NASA Technical Reports Server (NTRS)

Signorini, Sergio; Mannino, Antonio; Najjar, Raymond G., Jr.; Friedrichs, Marjorie A. M.; Cai, Wei-Jun; Salisbury, Joe; Wang, Zhaohui Aleck; Thomas, Helmuth; Shadwick, Elizabeth

2013-01-01

Underway and in situ observations of surface ocean pCO2, combined with satellite data, were used to develop pCO2 regional algorithms to analyze the seasonal and interannual variability of surface ocean pCO2 and sea-air CO2 flux for five physically and biologically distinct regions of the eastern North American continental shelf: the South Atlantic Bight (SAB), the Mid-Atlantic Bight (MAB), the Gulf of Maine (GoM), Nantucket Shoals and Georges Bank (NS+GB), and the Scotian Shelf (SS). Temperature and dissolved inorganic carbon variability are the most influential factors driving the seasonality of pCO2. Estimates of the sea-air CO2 flux were derived from the available pCO2 data, as well as from the pCO2 reconstructed by the algorithm. Two different gas exchange parameterizations were used. The SS, GB+NS, MAB, and SAB regions are net sinks of atmospheric CO2 while the GoM is a weak source. The estimates vary depending on the use of surface ocean pCO2 from the data or algorithm, as well as with the use of the two different gas exchange parameterizations. Most of the regional estimates are in general agreement with previous studies when the range of uncertainty and interannual variability are taken into account. According to the algorithm, the average annual uptake of atmospheric CO2 by eastern North American continental shelf waters is found to be between 3.4 and 5.4 Tg C/yr (areal average of 0.7 to 1.0 mol CO2 /sq m/yr) over the period 2003-2010.

The effect of ozone on nicotine desorption from model surfaces:evidence for heterogeneous chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Destaillats, Hugo; Singer, Brett C.; Lee, Sharon K.

Assessment of secondhand tobacco smoke exposure using nicotine as a tracer or biomarker is affected by sorption of the alkaloid to indoor surfaces and by its long-term re-emission into the gas phase. However, surface chemical interactions of nicotine have not been sufficiently characterized. Here, the reaction of ozone with nicotine sorbed to Teflon and cotton surfaces was investigated in an environmental chamber by monitoring nicotine desorption over a week following equilibration in dry or humid air (65-70 % RH). The Teflon and cotton surfaces had N{sub 2}-BET surface areas of 0.19 and 1.17 m{sup 2} g{sup -1}, and water massmore » uptakes (at 70 % RH) of 0 and 7.1 % respectively. Compared with dry air baseline levels in the absence of O{sub 3}, gas phase nicotine concentrations decrease, by 2 orders of magnitude for Teflon after 50 h at 20-45 ppb O{sub 3}, and by a factor of 10 for cotton after 100 h with 13-15 ppb O{sub 3}. The ratios of pseudo first-order rate constants for surface reaction (r) to long-term desorption (k) were r/k = 3.5 and 2.0 for Teflon and cotton surfaces, respectively. These results show that surface oxidation was competitive with desorption. Hence, oxidative losses could significantly reduce long-term re-emissions of nicotine from indoor surfaces. Formaldehyde, N-methylformamide, nicotinaldehyde and cotinine were identified as oxidation products, indicating that the pyrrolidinic N was the site of electrophilic attack by O{sub 3}. The presence of water vapor had no effect on the nicotine-O{sub 3} reaction on Teflon surfaces. By contrast, nicotine desorption from cotton in humid air was unaffected by the presence of ozone. These observations are consistent with complete inhibition of ozone-nicotine surface reactions in an aqueous surface film present in cotton but not in Teflon surfaces.« less

Influence of Mountains on Arctic Tropospheric Ozone

NASA Astrophysics Data System (ADS)

Whiteway, J. A.; Seabrook, J.

2015-12-01

Tropospheric ozone was measured above Ellesmere Island in the Canadian Arctic during spring using a differential absorption lidar (DIAL). Analysis of the observations revealed that mountains had a significant effect on the vertical distribution of ozone. Ozone depletion events were observed when air that had spent significant time near to the frozen surface of the Arctic Ocean reached Eureka. This air arrived at Eureka by flowing over the surrounding mountains. Surface level ozone depletion events were not observed during periods when mountains blocked the flow of air from over the sea ice. In the case of blocking there was an enhancement in the amount of ozone near the surface as air from the mid troposphere descended in the lee of the mountains. Three case studies will be presented.

In Situ Experiments To Reveal the Role of Surface Feature Sidewalls in the Cassie–Wenzel Transition

PubMed Central

2014-01-01

Waterproof and self-cleaning surfaces continue to attract much attention as they can be instrumental in various different technologies. Such surfaces are typically rough, allowing liquids to contact only the outermost tops of their asperities, with air being entrapped underneath. The formed solid–liquid–air interface is metastable and, hence, can be forced into a completely wetted solid surface. A detailed understanding of the wetting barrier and the dynamics of this transition is critically important for the practical use of the related surfaces. Toward this aim, wetting transitions were studied in situ at a set of patterned perfluoropolyether dimethacrylate (PFPEdma) polymer surfaces exhibiting surface features with different types of sidewall profiles. PFPEdma is intrinsically hydrophobic and exhibits a refractive index very similar to water. Upon immersion of the patterned surfaces into water, incident light was differently scattered at the solid–liquid–air and solid–liquid interface, which allows for distinguishing between both wetting states by dark-field microscopy. The wetting transition observed with this methodology was found to be determined by the sidewall profiles of the patterned structures. Partial recovery of the wetting was demonstrated to be induced by abrupt and continuous pressure reductions. A theoretical model based on Laplace’s law was developed and applied, allowing for the analytical calculation of the transition barrier and the potential to revert the wetting upon pressure reduction. PMID:25496232

Martian Atmospheric Pressure Static Charge Elimination Tool

NASA Technical Reports Server (NTRS)

Johansen, Michael R.

2014-01-01

A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

Refining surface net radiation estimates in arid and semi-arid climates of Iran

NASA Astrophysics Data System (ADS)

Golkar, Foroogh; Rossow, William B.; Sabziparvar, Ali Akbar

2018-06-01

Although the downwelling fluxes exhibit space-time scales of dependency on characteristic of atmospheric variations, especially clouds, the upward fluxes and, hence the net radiation, depends on the variation of surface properties, particularly surface skin temperature and albedo. Evapotranspiration at the land surface depends on the properties of that surface and is determined primarily by the net surface radiation, mostly absorbed solar radiation. Thus, relatively high spatial resolution net radiation data are needed for evapotranspiration studies. Moreover, in more arid environments, the diurnal variations of surface (air and skin) temperature can be large so relatively high (sub-daily) time resolution net radiation is also needed. There are a variety of radiation and surface property products available but they differ in accuracy, space-time resolution and information content. This situation motivated the current study to evaluate multiple sources of information to obtain the best net radiation estimate with the highest space-time resolution from ISCCP FD dataset. This study investigates the accuracy of the ISCCP FD and AIRS surface air and skin temperatures, as well as the ISCCP FD and MODIS surface albedos and aerosol optical depths as the leading source of uncertainty in ISCCP FD dataset. The surface air temperatures, 10-cm soil temperatures and surface solar insolation from a number of surface sites are used to judge the best combinations of data products, especially on clear days. The corresponding surface skin temperatures in ISCCP FD, although they are known to be biased somewhat high, disagreed more with AIRS measurements because of the mismatch of spatial resolutions. The effect of spatial resolution on the comparisons was confirmed using the even higher resolution MODIS surface skin temperature values. The agreement of ISCCP FD surface solar insolation with surface measurements is good (within 2.4-9.1%), but the use of MODIS aerosol optical depths as an alternative was checked and found to not improve the agreement. The MODIS surface albedos differed from the ISCCP FD values by no more than 0.02-0.07, but because these differences are mostly at longer wavelengths, they did not change the net solar radiation very much. Therefore to obtain the best estimate of surface net radiation with the best combination of spatial and temporal resolution, we developed a method to adjust the ISCCP FD surface longwave fluxes using the AIRS surface air and skin temperatures to obtain the higher spatial resolution of the latter (45 km), while retaining the 3-h time intervals of the former. Overall, the refinements reduced the ISCCP FD longwave flux magnitudes by about 25.5-42.1 W/m2 RMS (maximum difference -27.5 W/m2 for incoming longwave radiation and -59 W/m2 for outgoing longwave radiation) with the largest differences occurring at 9:00 and 12:00 UTC near local noon. Combining the ISCCP FD net shortwave radiation data and the AIRS-modified net longwave radiation data changed the total net radiation for summertime by 4.64 to 61.5 W/m2 and for wintertime by 1.06 to 41.88 W/m2 (about 11.1-39.2% of the daily mean).

Chemically Assisted Photocatalytic Oxidation System

NASA Technical Reports Server (NTRS)

Andino, Jean; Wu, Chang-Yu; Mazyck, David; Teixeira, Arthur A.

2009-01-01

The chemically assisted photocatalytic oxidation system (CAPOS) has been proposed for destroying microorganisms and organic chemicals that may be suspended in the air or present on surfaces of an air-handling system that ventilates an indoor environment. The CAPOS would comprise an upstream and a downstream stage that would implement a tandem combination of two partly redundant treatments. In the upstream stage, the air stream and, optionally, surfaces of the air-handling system would be treated with ozone, which would be generated from oxygen in the air by means of an electrical discharge or ultraviolet light. In the second stage, the air laden with ozone and oxidation products from the first stage would be made to flow in contact with a silica-titania photocatalyst exposed to ultraviolet light in the presence of water vapor. Hydroxyl radicals generated by the photocatalytic action would react with both carbon containing chemicals and microorganisms to eventually produce water and carbon dioxide, and ozone from the first stage would be photocatalytically degraded to O2. The net products of the two-stage treatment would be H2O, CO2, and O2.

Microparticle sampling by electrowetting-actuated droplet sweeping.

PubMed

Zhao, Yuejun; Cho, Sung Kwon

2006-01-01

This paper describes a new microparticle sampler where particles can be efficiently swept from a solid surface and sampled into a liquid medium using moving droplets actuated by the electrowetting principle. We successfully demonstrate that super hydrophilic (2 microm and 7.9 microm diameter glass beads of about 14 degrees contact angle), intermediate hydrophilic (7.5 microm diameter polystyrene beads of about 70 degrees contact angle), and super hydrophobic (7.9 microm diameter Teflon-coated glass beads and 3 microm size PTFE particles of over 110 degrees contact angles) particles on a solid surface are picked up by electrowetting-actuated moving droplets. For the glass beads as well as the polystyrene beads, the sampling efficiencies are over 93%, in particular over 98% for the 7.9 microm glass beads. For the PTFE particles, however, the sampling efficiency is measured at around 70%, relatively lower than that of the glass and polystyrene beads. This is due mainly to the non-uniformity in particle size and the particle hydrophobicity. In this case, the collected particles staying (adsorbing) on the air-to-water interface hinder the droplet from advancing. This particle sampler requires an extremely small amount of liquid volume (about 500 nanoliters) and will thus be highly compatible and easily integrated with lab-on-a-chip systems for follow-up biological/chemical analyses.

Tracking the MSL-SAM methane detection source location Through Mars Regional Atmospheric Modeling System (MRAMS)

NASA Astrophysics Data System (ADS)

Pla-García, Jorge

2016-04-01

1. Introduction: The putative in situ detection of methane by Sample Analysis at Mars (SAM) instrument suite on Curiosi-ty at Gale crater has garnered significant attention because of the potential implications for the presence of geological methane sources or indigenous Martian organisms [1, 2]. SAM reported detection of back-ground levels of atmospheric methane of mean value 0.69±0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). Additionally, in four sequential measurements spanning a 60-sol period, SAM observed elevated levels of methane of 7.2±2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source. There are many major unresolved questions regard-ing this detection: 1) What are the potential sources of the methane release? 2) What causes the rapid decrease in concentration? and 3) Where is the re-lease location? 4) How spatially extensive is the re-lease? 5) For how long is CH4 released? Regarding the first question, the source of methane, is so far not identified. It could be related with geo-logical process like methane release from clathrates [3], serpentinisation [4] and volcanism [5]; or due to biological activity from methanogenesis [6]. To answer the second question, the rapid decrease in concentration, it is important to note that the photo-chemical lifetime of methane is of order 100 years, much longer than the atmospheric mixing time scale, and thus the gas should tend to be well mixed except near a source or shortly after an episodic release. The observed spike of 7 ppb from the background of <1 ppb, and then the rapid return to the background lev-el could be due to a sink (destruction) or due to at-mospheric mixing. A wind mediated erosion process of ordinary quartz crystals was proposed to produce activated quartz grains, which sequester methane by forming covalent Si-C bonds. If this process is op-erational on Mars today, which some recent prelimi-nary studies on olivine indicate could be the case, then it might explain the observed fast destruction of methane [7]. In an effort to better address the potential mixing and remaining questions, atmospheric circulation studies of Gale Crater were performed with the Mars Re-gional Atmospheric Modeling System (MRAMS). The model was focused on rover locations using nested grids with a spacing of 330 meters on the in-nermost grid that is centered over the landing [8, 9]. MRAMS is ideally suited for this investigation; the model is explicitly designed to simulate Mars' at-mospheric circulations at the mesoscale and smaller with realistic, high-resolution surface properties [10, 11]. In order to characterize seasonal mixing changes throughout the Martian year, simulations were con-ducted at Ls 0, 90, 180 and 270. Two additional sim-ulations at Ls 225 and 315 were explored to better understand the unique meteorological setting cen-tered around Ls 270. Ls 270 was shown to be an anomalous season when air within and outside the crater was well mixed by strong, flushing, northerly flow and large amplitude breaking mountain waves: air flowing downslope at night is cold enough to penetrate all the way to the surface. At other seasons, the air in the crater is more isolated -but not com-pletely- from the surrounding environment: mesoscale simulations indicate that the air flowing down the crater rims does not easily make it to the crater floor. Instead, the air encounters very cold and stable air pooled in the bottom of the crater, which forces the air to glide right over the colder, more dense air below. Thus, the mixing of near-surface crater air with the external environment is potentially more limited than around Ls 270. 2. Tracking methane source location The rise in concentration was reported to start around sol 300 (˜Ls 336), peaked shortly after sol 520 (˜Ls 82), and then dropped to background val-ues prior to sol 575 (˜Ls 103). Two scenarios are considered in the context of the circulations predicted by MRAMS. The first scenario is the release of methane from somewhere outside the crater. The second is a release of methane within the crater. In both cases, the release is assumed to take place near the season when the rise of concen-tration was first noted (˜Ls 336). This is a transition-al time at Gale Crater, when the flushing winds are giving way to the more isolated crater scenario: In the situation where the release was outside the crater, the experiment assumes a uniform, elevated abundance of CH4 outside the crater, and mixing should be sufficient to bring the crater methane abundance to something close to the larger-scale environmental value. As the crater becomes more isolated with time, the methane abundance in the crater will begin to lag whatever the value is outside the crater. If the release was far from the crater, the external ˜7 ppbv value might be expected to slowly decrease as the methane becomes increasingly well-mixed on a global scale, and as some of that air mix-es slowly into the crater. For the elevated methane levels in the crater to drop rapidly back to back-ground levels, at least two things would need to hap-pen. First, the external crater environment would have to drop at least as rapidly to the background levels. This seems possible only if there is very deep mixing that spreads the release through a very large volume of atmosphere, or if a rapid destruction mechanism is invoked. The second thing that would have to happen is that the crater air would have to mix nearly completely with the external crater air. The model results at Ls 90, which bounds the period between the observed peak and the return to the background levels, may be supportive of this idea. However, while mixing seems limited, it may still be possible that the mixing degree and time scale is sufficient to affect the necessary change. In the second scenario, the release is assumed to be within the crater. In this case, some mixing of this air with external crater air at background values can be assumed. Depending on the rate of mixing, it is pos-sible that the value could decay to the background levels in the given time. Thus, from a mixing stand-point, the second scenario seems at least plausible. Some preliminary work, including tracer gases into the model, is being performed to establish the amount of mixing during the limited mixing epochs. Preliminary results may support the idea that during periods of limited mixing, there could be enough time for methane to bind to activated mineral surfac-es through wind erosion. More work is needed to establish the amount of mixing and to de-termine which scenario is more likely. References: [1] Webster et al. (2013), LPI contributions, 1719: 1366; [2] Webster et al. (2015), Science, vol. 347, no. 6220, 415-417; [3] Chastain and Chevrier (2007). Planet. Space Science, 55, 1246-1256; [4] Oze and Sharma (2005). Geophys. Res. Lett., 32, L10203; [5] Etiope et al. (2007), J. Volcanol. Geo-therm. Res., 165, 76-86; [6] Reid et al. (2006), Int. J. Astrobiol., 5, 89-97; [7] Jensen et al. (2014), Icarus, 236, 24-27; [8] Rafkin, S. C. R. et al. (2001), Icarus, 151, 228-256;?[9] Rafkin, S. C. R. et al. (2002), Na-ture, 419, 697-699. [10] Pla-Garcia et al. (2016), Icarus, Accepted; [11] Rafkin S.C.R. et al. (2016), Icarus, Accepted

BOREAS AES Five-Day Averaged Surface Meteorological and Upper Air Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Strub, Richard; Newcomer, Jeffrey A.

2000-01-01

The Canadian Atmospheric Environment Service (AES) provided BOREAS with hourly and daily surface meteorological data from 23 of the AES meteorological stations located across Canada and upper air data from 1 station at The Pas, Manitoba. Due to copyright restrictions on the full resolution surface meteorological data, this data set contains 5-day average values for the surface parameters. The upper air data are provided in their full resolution form. The 5-day averaging was performed in order to create a data set that could be publicly distributed at no cost. Temporally, the surface meteorological data cover the period of January 1975 to December 1996 and the upper air data cover the period of January 1961 to November 1996. The data are provided in tabular ASCII files, and are classified as AFM-staff data. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Volatile metabolite production of spoilage micro-organisms on a mixed-lettuce agar during storage at 7 degrees C in air and low oxygen atmosphere.

PubMed

Ragaert, P; Devlieghere, F; Devuyst, E; Dewulf, J; Van Langenhove, H; Debevere, J

2006-11-01

This paper describes the volatile metabolite production of spoilage bacteria (Pantoea agglomerans and Rahnella aquatilis) and spoilage yeasts (Pichia fermentans and Cryptococcus laurentii), previously isolated from mixed lettuce, on a simulation medium of shredded mixed lettuce (mixed-lettuce agar) both under air conditions and modified atmosphere (MA)-conditions at 7 degrees C. These latter conditions simulated the equilibrium modified atmosphere packaging, which is used to extend the shelf-life of shredded mixed lettuce. Besides volatile metabolites, organic acid metabolites and consumption of sugars were measured. Microbiological growth on the mixed-lettuce agar resulted in metabolite production and consumption of sugars. Bacteria and yeasts produced a range of volatile organic compounds both under air conditions and MA-conditions: ethanol, ethyl acetate, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2,3-butanedione, 3-methyl-1-pentanol, 1-butanol and 1-hexanol. Under MA-conditions, 2-methyl-1-butanol, 3-methyl-1-butanol and ethanol were the first compounds that were detected in the headspace as being produced by the inoculated micro-organisms. In the case of the yeast P. fermentans, production of these compounds was detected from a count of 5.0+/-0.1 log cfu/cm(2) with a fast increase when exceeding 6.0-6.5 log cfu/cm(2). Unlike P. fermentans, the yeast C. laurentii showed a slow metabolism under MA-conditions, compared to air conditions. In the case of the bacteria, production of 2-methyl-1-butanol and 3-methyl-1-butanol was detected starting from a count of 6.7+/-0.1 log cfu/cm(2) in the case of R. aquatilis and from a count of 7.1+/-0.4 log cfu/cm(2) in the case of P. agglomerans with a fast increase when exceeding 8 log cfu/cm(2). No production of ethanol by the bacteria under MA-conditions was detected in contradiction to air conditions. It could be concluded that, if these counts are reached on the cut surfaces of shredded mixed lettuce which are simulated by the mixed-lettuce agar, sensorial quality of shredded mixed lettuce could be influenced by the microbiological production of metabolites.

Oxidation Resistance of Materials Based on Ti3AlC2 Nanolaminate at 600 °C in Air

NASA Astrophysics Data System (ADS)

Ivasyshyn, Andrij; Ostash, Orest; Prikhna, Tatiana; Podhurska, Viktoriya; Basyuk, Tatiana

2016-08-01

The oxidation behavior of Ti3AlC2-based materials had been investigated at 600 °C in static air for 1000 h. It was shown that the intense increase of weight gain per unit surface area for sintered material with porosity of 22 % attributed to oxidation of the outer surface of the specimen and surfaces of pores in the bulk material. The oxidation kinetics of the hot-pressed Ti3AlC2-based material with 1 % porosity remarkably increased for the first 15 h and then slowly decreased. The weight gain per unit surface area for this material was 1.0 mg/cm2 after exposition for 1000 h. The intense initial oxidation of Ti3AlC2-based materials can be eliminated by pre-oxidation treatment at 1200 °C in air for 2 h. As a result, the weight gain per unit surface area for the pre-oxidized material did not exceed 0.11 mg/cm2 after 1000 h of exposition at 600 °C in air. It was demonstrated that the oxidation resistance of Ti3AlC2-based materials can be significantly improved by niobium addition.

Cassini orbiter is moved to PHSF after arriving at SLF

NASA Technical Reports Server (NTRS)

1997-01-01

Workers prepare to move the shipping container with the Cassini orbiter inside the Payload Hazardous Servicing Facility (PHSF) for prelaunch processing, testing and integration. The orbiter arrived at KSC's Shuttle Landing Facility in a U.S. Air Force C-17 air cargo plane from Edwards Air Force Base, California. The orbiter and the Huygens probe already being processed at KSC are the two primary components of the Cassini spacecraft, which will be launched on a Titan IVB/Centaur expendable launch vehicle from Cape Canaveral Air Station. Cassini will explore Saturn, its rings and moons for four years. The Huygens probe, designed and developed for the European Space Agency (ESA), will be deployed from the orbiter to study the clouds, atmosphere and surface of Saturn's largest moon, Titan. The orbiter was designed and assembled at NASA's Jet Propulsion Laboratory in California. Following postflight inspections, integration of the 12 science instruments not already installed on the orbiter will be completed. Then, the parabolic high-gain antenna and the propulsion module will be mated to the orbiter, followed by the Huygens probe, which will complete spacecraft integration. The Cassini mission is targeted for an Oct. 6 launch to begin its 6.7-year journey to the Saturnian system. Arrival at the planet is expected to occur around July 1, 2004.

Heat and turbulent kinetic energy budgets for surface layer cooling induced by the passage of Hurricane Frances (2004)

NASA Astrophysics Data System (ADS)

Huang, Peisheng; Sanford, Thomas B.; Imberger, JöRg

2009-12-01

Heat and turbulent kinetic energy budgets of the ocean surface layer during the passage of Hurricane Frances were examined using a three-dimensional hydrodynamic model. In situ data obtained with the Electromagnetic-Autonomous Profiling Explorer (EM-APEX) floats were used to set up the initial conditions of the model simulation and to compare to the simulation results. The spatial heat budgets reveal that during the hurricane passage, not only the entrainment in the bottom of surface mixed layer but also the horizontal water advection were important factors determining the spatial pattern of sea surface temperature. At the free surface, the hurricane-brought precipitation contributed a negligible amount to the air-sea heat exchange, but the precipitation produced a negative buoyancy flux in the surface layer that overwhelmed the instability induced by the heat loss to the atmosphere. Integrated over the domain within 400 km of the hurricane eye on day 245.71 of 2004, the rate of heat anomaly in the surface water was estimated to be about 0.45 PW (1 PW = 1015 W), with about 20% (0.09 PW in total) of this was due to the heat exchange at the air-sea interface, and almost all the remainder (0.36 PW) was downward transported by oceanic vertical mixing. Shear production was the major source of turbulent kinetic energy amounting 88.5% of the source of turbulent kinetic energy, while the rest (11.5%) was attributed to the wind stirring at sea surface. The increase of ocean potential energy due to vertical mixing represented 7.3% of the energy deposited by wind stress.

Impact of indoor surface material on perceived air quality.

PubMed

Senitkova, I

2014-03-01

The material combination impact on perceived indoor air quality for various surface interior materials is presented in this paper. The chemical analysis and sensory assessments identifies health adverse of indoor air pollutants (TVOCs). In this study, emissions and odors from different common indoor surface materials were investigated in glass test chamber under standardized conditions. Chemical measurements (TVOC concentration) and sensory assessments (odor intensity, air acceptability) were done after building materials exposure to standardized conditions. The results of the chemical and sensory assessment of individual materials and their combinations are compared and discussed within the paper. The using possibility of individual material surface sorption ability was investigated. The knowledge of targeted sorption effects can be used in the interior design phase. The results demonstrate the various sorption abilities of various indoor materials as well as the various sorption abilities of the same indoor material in various combinations. Copyright © 2013 Elsevier B.V. All rights reserved.

The Diversity and Distribution of Fungi on Residential Surfaces

PubMed Central

Adams, Rachel I.; Miletto, Marzia; Taylor, John W.; Bruns, Thomas D.

2013-01-01

The predominant hypothesis regarding the composition of microbial assemblages in indoor environments is that fungal assemblages are structured by outdoor air with a moderate contribution by surface growth, whereas indoor bacterial assemblages represent a mixture of bacteria entered from outdoor air, shed by building inhabitants, and grown on surfaces. To test the fungal aspect of this hypothesis, we sampled fungi from three surface types likely to support growth and therefore possible contributors of fungi to indoor air: drains in kitchens and bathrooms, sills beneath condensation-prone windows, and skin of human inhabitants. Sampling was done in replicated units of a university-housing complex without reported mold problems, and sequences were analyzed using both QIIME and the new UPARSE approach to OTU-binning, to the same result. Surfaces demonstrated a mycological profile similar to that of outdoor air from the same locality, and assemblages clustered by surface type. “Weedy” genera typical of indoor air, such as Cladosporium and Cryptococcus, were abundant on sills, as were a diverse set of fungi of likely outdoor origin. Drains supported more depauperate assemblages than the other surfaces and contained thermotolerant genera such as Exophiala, Candida, and Fusarium. Most surprising was the composition detected on residents’ foreheads. In addition to harboring Malassezia, a known human commensal, skin also possessed a surprising richness of non-resident fungi, including plant pathogens such as ergot (Claviceps purperea). Overall, fungal richness across indoor surfaces was high, but based on known autecologies, most of these fungi were unlikely to be growing on surfaces. We conclude that while some endogenous fungal growth on typical household surfaces does occur, particularly on drains and skin, all residential surfaces appear – to varying degrees – to be passive collectors of airborne fungi of putative outdoor origin, a view of the origins of the indoor microbiome quite different from bacteria. PMID:24223861

AIRS Observations of DomeC in Antarctica and Comparison with Automated Weather Stations (AWS)

NASA Technical Reports Server (NTRS)

Aumann, Hartmut H.; Gregorich, Dave; Broberg, Steve

2006-01-01

We compare the surface temperatures at Dome Concordia (DomeC) deduced from AIRS data and two Automatic Weather Stations at Concordia Station: AWS8989 , which has been in operation since December 1996, and AWS.it, for which data are available between January and November 2005. The AWS8989 readings are on average 3 K warmer than the AWS.it readings, with a warmer bias in the Antarctic summer than in the winter season. Although AIRS measures the skin brightness temperature, while the AWS reports the temperature of the air at 3 meter above the surface, the AIRS measurements agree well with the AWS.it readings for all data and separately for the summer and winter seasons, if data taken in the presence of strong surface inversions are filtered out. This can be done by deducing the vertical temperature gradient above the surface directly from the AIRS temperature sounding channels or indirectly by noting that extreme vertical gradients near the surface are unlikely if the wind speed is more than a few meters per second. Since the AIRS measurements are very well calibrated, the agreement with AWS.it is very encouraging. The warmer readings of AWS8989 are likely due to thermal contamination of the AWS8989 site by the increasing activity at Concordia Station. Data from an AWS.it quality station could be used for the evaluation of radiometric accuracy and stability of polar orbiting sounders at low temperatures. Unfortunately, data from AWS.it was available only for a limited time. The thermal contamination of the AWS8989 data makes long-term trends deduced from AWS8989 and possibly results about the rapid Antarctic warming deduced from other research stations on Antarctica suspect. AIRS is the first hyperspectral infrared sounder designed in support of weather forecasting and climate research. It was launched in May 2002 on the EOS Aqua spacecraft into a 704 km altitude polar sun-synchronous orbit. The lifetime of AIRS, estimated before launch to be at least 5 years is, based on the latest evaluation, limited by the amount of attitude control gas on the EOS Aqua spacecraft, which is expected to last through 2015.

Biobriefcase electrostatic aerosol collector

DOEpatents

Bell, Perry M [Tracy, CA; Christian, Allen T [Madison, WI; Bailey, Christopher G [Pleasanton, CA; Willis, Ladona [Manteca, CA; Masquelier, Donald A [Tracy, CA; Nasarabadi, Shanavaz L [Livermore, CA

2009-03-17

A system for sampling air and collecting particles entrained in the air comprising a receiving surface, a liquid input that directs liquid to the receiving surface and produces a liquid surface, an air input that directs the air so that the air with particles entrained in the air impact the liquid surface, and an electrostatic contact connected to the liquid that imparts an electric charge to the liquid. The particles potentially including bioagents become captured in the liquid by the air with particles entrained in the air impacting the liquid surface. Collection efficiency is improved by the electrostatic contact electrically charging the liquid. The effects of impaction and adhesion due to electrically charging the liquid allows a unique combination in a particle capture medium that has a low fluid consumption rate while maintaining high efficiency.

Simultaneous tuning of chemical composition and topography of copolymer surfaces: micelles as building blocks.

PubMed

Zhao, Ning; Zhang, Xiaoyan; Zhang, Xiaoli; Xu, Jian

2007-05-14

A simple method is described for controlling the surface chemical composition and topography of the diblock copolymer poly(styrene)-b-poly(dimethylsiloxane)(PS-b-PDMS) by casting the copolymer solutions from solvents with different selectivities. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively, and the wetting behavior was studied by water contact angle (CA) and sliding angle (SA) and by CA hysteresis. Chemical composition and morphology of the surface depend on solvent properties, humidity of the air, solution concentration, and block lengths. If the copolymer is cast from a common solvent, the resultant surface is hydrophobic, with a flat morphology, and dominated by PDMS on the air side. From a PDMS-selective solvent, the surface topography depends on the morphology of the micelles. Starlike micelles give rise to a featureless surface nearly completely covered by PDMS, while crew-cut-like micelles lead to a rough surface with a hierarchical structure that consists partly of PDMS. From a PS-selective solvent, however, surface segregation of PDMS was restricted, and the surface morphology can be controlled by vapor-induced phase separation. On the basis of the tunable surface roughness and PDMS concentration on the air side, water repellency of the copolymer surface could be tailored from hydrophobic to superhydrophobic. In addition, reversible switching behavior between hydrophobic and superhydrophobic can be achieved by exposing the surface to solvents with different selectivities.

Monitoring minimization of grade B environments based on risk assessment using three-dimensional airflow measurements and computer simulation.

PubMed

Katayama, Hirohito; Higo, Takashi; Tokunaga, Yuji; Katoh, Shigeo; Hiyama, Yukio; Morikawa, Kaoru

2008-01-01

A practical, risk-based monitoring approach using the combined data collected from actual experiments and computer simulations was developed for the qualification of an EU GMP Annex 1 Grade B, ISO Class 7 area. This approach can locate and minimize the representative number of sampling points used for microbial contamination risk assessment. We conducted a case study on an aseptic clean room, newly constructed and specifically designed for the use of a restricted access barrier system (RABS). Hotspots were located using three-dimensional airflow analysis based on a previously published empirical measurement method, the three-dimensional airflow analysis. Local mean age of air (LMAA) values were calculated based on computer simulations. Comparable results were found using actual measurements and simulations, demonstrating the potential usefulness of such tools in estimating contamination risks based on the airflow characteristics of a clean room. Intensive microbial monitoring and particle monitoring at the Grade B environmental qualification stage, as well as three-dimensional airflow analysis, were also conducted to reveal contamination hotspots. We found representative hotspots were located at perforated panels covering the air exhausts where the major piston airflows collect in the Grade B room, as well as at any locations within the room that were identified as having stagnant air. However, we also found that the floor surface air around the exit airway of the RABS EU GMP Annex 1 Grade A, ISO Class 5 area was always remarkably clean, possibly due to the immediate sweep of the piston airflow, which prevents dispersed human microbes from falling in a Stokes-type manner on settling plates placed on the floor around the Grade A exit airway. In addition, this airflow is expected to be clean with a significantly low LMAA. Based on these observed results, we propose a simplified daily monitoring program to monitor microbial contamination in Grade B environments. To locate hotspots we propose using a combination of computer simulation, actual airflow measurements, and intensive environmental monitoring at the qualification stage. Thereafter, instead of particle or microbial air monitoring, we recommend the use of microbial surface monitoring at the main air exhaust. These measures would be sufficient to assure the efficiency of the monitoring program, as well as to minimize the number of surface sampling points used in environments surrounding a RABS.

Cleaning and modification of intraorally contaminated titanium discs with calcium phosphate powder abrasive treatment.

PubMed

Tastepe, Ceylin S; Liu, Yuelian; Visscher, Corine M; Wismeijer, Daniel

2013-11-01

The aim of this study was to evaluate the cleaning efficiency on intraorally contaminated titanium discs by using calcium phosphate and air powder abrasive (APA) treatment. The modification of titanium surface (SLA) was evaluated and compared with the conventional air powder abrasive methods and phosphoric acid. This treatment modality might give new perspectives for peri-implant surface treatment. A total of 36 SLA surface titanium discs were kept in the human mouth for 48 h by 14 volunteers. The intraorally contaminated discs were stained with erythrosine dye to make the biofilm visible. Discs were randomly assigned to one of the six groups: APA without powder-only water and air (Control). APA with Hydroxylapatite (HA). APA with Hydroxylapatite and Calcium Phosphate (HA + TCP). APA with Titanium Dioxide (TiO2). APA with EMS Soft Subgingival powder (EMS). Phosphoric Acid. Light microscope photos were taken during the treatment. Following the cleaning, the residual biofilm, surface changes, and surface chemical content were evaluated using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). A systematic random sampling protocol and a point counting method were applied for the quantitative evaluation of the remaining biofilm. Multiple comparisons within and between groups are performed by Kruskall Wallis test and if significant Mann-Whitney U-test as post hoc testing is applied. The significance level was P < 0.05. All methods with the exception of phosphoric acid could decrease the initial amount of biofilm significantly. Among all air powder abrasive treatments, the HA + TCP group showed the best results with 99% biofilm removal, followed by HA and EMS powders. The cleaning method caused minimal changes to the surface structure. With the exception of the control group, all air powder applications caused sharp edges around the grooves in the implant surface to be rounded. TiO2 powder caused less change than HA and HA + TCP. Phosphoric acid did not cause a visible surface change on the SEM photos. Powder particles remnants were observed on and impacted in the titanium surface. In the HA and HA + TCP group, a Ca content was observed varying between 2% and 5%. In the control group, saliva and biofilm-related elements were observed. Using the air powder abrasive method with calcium phosphate powders on contaminated titanium discs, an efficient implant cleaning and surface modification can be achieved. This method should be further improved as it has possible potential to be used as an implant surface treatment method for implants involved with peri-implantitis. © 2012 John Wiley & Sons A/S.

The successful of finite element to invent particle cleaning system by air jet in hard disk drive

NASA Astrophysics Data System (ADS)

Jai-Ngam, Nualpun; Tangchaichit, Kaitfa

2018-02-01

Hard Disk Drive manufacturing has faced very challenging with the increasing demand of high capacity drives for Cloud-based storage. Particle adhesion has also become increasingly important in HDD to gain more reliability of storage capacity. The ability to clean on surfaces is more complicated in removing such particles without damaging the surface. This research is aim to improve the particle cleaning in HSA by using finite element to develop the air flow model then invent the prototype of air cleaning system to remove particle from surface. Surface cleaning by air pressure can be applied as alternative for the removal of solid particulate contaminants that is adhering on a solid surface. These technical and economic challenges have driven the process development from traditional way that chemical solvent cleaning. The focus of this study is to develop alternative way from scrub, ultrasonic, mega sonic on surface cleaning principles to serve as a foundation for the development of new processes to meet current state-of-the-art process requirements and minimize the waste from chemical cleaning for environment safety.

Muons in air showers at the Pierre Auger Observatory: Mean number in highly inclined events

DOE PAGES

Aab, Alexander

2015-03-09

We present the first hybrid measurement of the average muon number in air showers at ultra-high energies, initiated by cosmic rays with zenith angles between 62° and 80° . Our measurement is based on 174 hybrid events recorded simultaneously with the Surface Detector array and the Fluorescence Detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 10 19 eV shower with a zenith angle of 67°, which arrives at the Surface Detector array atmore » an altitude of 1450 m above sea level, contains on average (2.68 ± 0.04 ± 0.48 (sys.)) × 10 7 muons with energies larger than 0.3 GeV. Finally, the logarithmic gain d ln N µ/d ln E of muons with increasing energy between 4 × 10 18 eV and 5 × 10 19 eV is measured to be (1.029 ± 0.024 ± 0.030 (sys.)).« less

The Breathing Snowpack: Pressure-induced Vapor Flux of Temperate Snow

NASA Astrophysics Data System (ADS)

Drake, S. A.; Selker, J. S.; Higgins, C. W.

2017-12-01

As surface air pressure increases, hydrostatic compression of the air column forces atmospheric air into snowpack pore space. Likewise, as surface air pressure decreases, the atmospheric air column decompresses and saturated air exits the snow. Alternating influx and efflux of air can be thought of as a "breathing" process that produces an upward vapor flux when air above the snow is not saturated. The impact of pressure-induced vapor exchange is assumed to be small and is thus ignored in model parameterizations of surface processes over snow. Rationale for disregarding this process is that large amplitude pressure changes as caused by synoptic weather patterns are too infrequent to credibly impact vapor flux. The amplitude of high frequency pressure changes is assumed to be too small to affect vapor flux, however, the basis for this hypothesis relies on pressure measurements collected over an agricultural field (rather than snow). Resolution of the impact of pressure changes on vapor flux over seasonal cycles depends on an accurate representation of the magnitude of pressure changes caused by changes in wind as a function of the frequency of pressure changes. High precision in situ pressure measurements in a temperature snowpack allowed us to compute the spectra of pressure changes vs. wind forcing. Using a simplified model for vapor exchange we then computed the frequency of pressure changes that maximize vapor exchange. We examine and evaluate the seasonal impact of pressure-induced vapor exchange relative to other snow ablation processes.

Information transfer across the scales of climate variability: The effect of the 7-8 year cycle on the annual and interannual scales

NASA Astrophysics Data System (ADS)

Palus, Milan; Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, Sergey; Tsonis, Anastasios

2016-04-01

Complexity of the climate system stems not only from the fact that it is variable over a huge range of spatial and temporal scales, but also from the nonlinear character of the climate system that leads to interactions of dynamics across scales. The dynamical processes on large time scales influence variability on shorter time scales. This nonlinear phenomenon of cross-scale causal interactions can be observed due to the recently introduced methodology [1] which starts with a wavelet decomposition of a multi-scale signal into quasi-oscillatory modes of a limited bandwidth, described using their instantaneous phases and amplitudes. Then their statistical associations are tested in order to search for interactions across time scales. An information-theoretic formulation of the generalized, nonlinear Granger causality [2] uncovers causal influence and information transfer from large-scale modes of climate variability with characteristic time scales from years to almost a decade to regional temperature variability on short time scales. In analyses of air temperature records from various European locations, a quasioscillatory phenomenon with the period around 7-8 years has been identified as the factor influencing variability of surface air temperature (SAT) on shorter time scales. Its influence on the amplitude of the SAT annual cycle was estimated in the range 0.7-1.4 °C and the effect on the overall variability of the SAT anomalies (SATA) leads to the changes 1.5-1.7 °C in the annual SATA means. The strongest effect of the 7-8 year cycle was observed in the winter SATA means where it reaches 4-5 °C in central European station and reanalysis data [3]. This study is supported by the Ministry of Education, Youth and Sports of the Czech Republic within the Program KONTAKT II, Project No. LH14001. [1] M. Palus, Phys. Rev. Lett. 112 078702 (2014) [2] M. Palus, M. Vejmelka, Phys. Rev. E 75, 056211 (2007) [3] N. Jajcay, J. Hlinka, S. Kravtsov, A. A. Tsonis, M. Palus, Time-scales of the European surface air temperature variability: The role of the 7-8 year cycle. Geophys. Res. Lett., in press, DOI: 10.1002/2015GL067325

Surgical outcome of deep anterior lamellar keratoplasty with air-assisted manual dissection for corneas with previous inflammation or fibrosis

PubMed Central

Ho, Yi-Ju; Wu, Cheng-Hsiu; Chen, Hung-Chi; Hsiao, Chin-Shi; Hsueh, Yi-Jen; Ma, David Hui-Kang

2017-01-01

PURPOSE: To report our experience in air-assisted manual dissection deep anterior lamellar keratoplasty (DALK) for the treatment of corneal scar with previous inflammation and fibrosis. MATERIALS AND METHODS: We retrospectively reviewed the medical history of 21 patients (male:female = 13:8 mean age 41.9 years old) with corneal pathology from previous infection and inflammation. Trephination diameter ranged from 7.0 to 8.0 mm, and the graft was oversized by 0.25–0.50 mm. Debulking technique was performed to expose Descemet's membrane after filling stroma with air. Starting from postoperative 3 months, selective suture removal was performed to reduce corneal astigmatism. RESULTS: The mean follow-up period was 59.9 ± 19.8 (20–96) months. Intraoperative microperforation occurred in 2 eyes (9.5%); however, there was no shift to penetrating keratoplasty. Air-bubble tamponade was performed in 7 eyes (33.3%) for postoperative gapping of the graft. There were 2 failed grafts (9.5%) due to corneal ulcer while all the other grafts remained clear throughout follow-up. The mean preoperative best-corrected visual acuity (BCVA) was 1.84 ± 0.66 logMAR, which improved to 0.74 ± 0.63 (P < 0.01). The average sphere power was − 0.88 ± 3.88 diopter (D), average cylinder power 3.03 ± 1.46D, and average endothelial count 1877 ± 375 cells/mm2. CONCLUSION: In severe ocular surface diseases, big-bubble technique frequently failed to separate predescemtic plane; however, it effectively created air-filled stroma which was easier to remove. Although BCVA was suboptimal due to ocular surface disorders, graft survival and clarity rate is high, justifying the application of DALK in these cases. PMID:29296551

Box-Behnken statistical design to optimize thermal performance of energy storage systems

NASA Astrophysics Data System (ADS)

Jalalian, Iman Joz; Mohammadiun, Mohammad; Moqadam, Hamid Hashemi; Mohammadiun, Hamid

2018-05-01

Latent heat thermal storage (LHTS) is a technology that can help to reduce energy consumption for cooling applications, where the cold is stored in phase change materials (PCMs). In the present study a comprehensive theoretical and experimental investigation is performed on a LHTES system containing RT25 as phase change material (PCM). Process optimization of the experimental conditions (inlet air temperature and velocity and number of slabs) was carried out by means of Box-Behnken design (BBD) of Response surface methodology (RSM). Two parameters (cooling time and COP value) were chosen to be the responses. Both of the responses were significantly influenced by combined effect of inlet air temperature with velocity and number of slabs. Simultaneous optimization was performed on the basis of the desirability function to determine the optimal conditions for the cooling time and COP value. Maximum cooling time (186 min) and COP value (6.04) were found at optimum process conditions i.e. inlet temperature of (32.5), air velocity of (1.98) and slab number of (7).

Adsorption of 1- and 2-butylimidazoles at the copper/air and steel/air interfaces studied by sum frequency generation vibrational spectroscopy.

PubMed

Casford, Michael T L; Davies, Paul B

2012-07-24

The structure of thin films of 1- and 2-butylimidazoles adsorbed on copper and steel surfaces under air was examined using sum frequency generation (SFG) vibrational spectroscopy in the ppp and ssp polarizations. Additionally, the SFG spectra of both isomers were recorded at 55 °C at the liquid imidazole/air interface for reference. Complementary bulk infrared, reflection-absorption infrared spectroscopy (RAIRS), and Raman spectra of both imidazoles were recorded for assignment purposes. The SFG spectra in the C-H stretching region at the liquid/air interface are dominated by resonances from the methyl end group of the butyl side chain of the imidazoles, indicating that they are aligned parallel or closely parallel to the surface normal. These are also the most prominent features in the SFG spectra on copper and steel. In addition, both the ppp and ssp spectra on copper show resonances from the C-H stretching modes of the imidazole ring for both isomers. The ring C-H resonances are completely absent from the spectra on steel and at the liquid/air interface. The relative intensities of the SFG spectra can be interpreted as showing that, on copper, under air, both butylimidazoles are adsorbed with their butyl side chains perpendicular to the interface and with the ring significantly inclined away from the surface plane and toward the surface normal. The SFG spectra of both imidazoles on steel indicate an orientation where the imidazole rings are parallel or nearly parallel to the surface. The weak C-H resonances from the ring at the liquid/air interface suggest that the tilt angle of the ring from the surface normal at this interface is significantly greater than it is on copper.

Satellite (SWOT) and Airborne (AirSWOT) Wide-Swath Altimeters to Study the Garonne River

NASA Astrophysics Data System (ADS)

Biancamaria, S.; Rodriguez, E.; Goutal, N.; Ricci, S.; Mognard, N.; Rogel, P.; Le Pape, E.

2013-09-01

The future NASA/CNES Surface Water and Ocean Topography (SWOT) satellite mission will provide global 2D maps of water elevations, water surface volume change and river discharge at an unprecedented resolution. To prepare this mission, airborne campaigns, called AirSWOT, will fly over the Garonne River (and other targets of interest) in 2014. To plan AirSWOT flights over the Garonne, 1D and 2D hydrodynamic models of the 50 km Garonne River reach between Tonneins and La Reole towns developed by the Laboratoire National d'Hydraulique et Environnement (LNHE) will be used. Models outputs will help to validate airborne measurements. After validation, AirSWOT measurements will be assimilated in the models to reduce model errors. Finally, potential algorithms to estimate discharge from AirSWOT and SWOT observations will be tested over this river reach. This paper presents the study domain, the hydrodynamic models and their use in the context of AirSWOT campaigns in France.

Global and Regional Seasonal Variability of Mid-Tropospheric CO2 as Measured by the Atmospheric Infrared Sounder (AIRS)

NASA Technical Reports Server (NTRS)

Pagano, Thomas S.; Olsen, Edward T.; Nguyen, Hai

2012-01-01

The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the Earth Observing System (EOS) Aqua Spacecraft, launched on May 4, 2002 into a near polar sun-synchronous orbit. AIRS has 2378 infrared channels ranging from 3.7 ?m to 15.4 ?m and a 13.5 km footprint at nadir. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles and trace gas amounts for CO2, CO, SO2, O3 and CH4. AIRS CO2 climatologies have been shown to be useful for identifying anomalies associated with geophysical events such as El Nino-Southern Oscillation or Madden-Julian oscillation. In this study, monthly representations of mid-tropospheric CO2 are constructed from 10 years of AIRS Version 5 monthly Level 3 data. We compare the AIRS mid-tropospheric CO2 representations to ground-based measurements from the Scripps and National Oceanic and Atmospheric Administration Climate Modeling and Diagnostics Laboratory (NOAA CMDL) ground networks to better understand the phase lag of the CO2 seasonal cycle between the surface and middle troposphere. Results show only a small phase lag in the tropics that grows to approximately two months in the northern latitudes.

Understanding Arctic surface temperature differences in reanalyses

NASA Astrophysics Data System (ADS)

Cullather, R. I.; Zhao, B.; Shuman, C. A.; Nowicki, S.

2017-12-01

Reanalyses in the Arctic are widely used for model evaluation and for understanding contemporary climate change. Nevertheless, differences among reanalyses in fundamental meteorological variables including surface air temperature are large. For example, the 1980-2009 mean surface air temperature for the north polar cap (70°N-90°N) among global reanalyses span a range of 2.4 K, which approximates the average warming trend from these reanalyses over the 30-year period of 2.1 K. Understanding these differences requires evaluation over the three principal surface domains of the Arctic: glaciated land, the unglaciated terrestrial surface, and sea ice/ocean. An examination is conducted of contemporary global reanalyses of the ECMWF Interim project, NASA MERRA, MERRA-2, JRA-55, and NOAA CFSR using available in situ data and assessments of the surface energy budget. Overly-simplistic representations of the Greenland Ice Sheet surface are found to be associated with local warm air temperature biases in winter. A review of progress made in the development of the MERRA-2 land-ice representation is presented. Large uncertainty is also found in temperatures over the Arctic tundra and boreal forest zone. But a key focus of temperature differences for northern high latitudes is the Arctic Ocean. Near-surface air temperature differences over the Arctic Ocean are found to be related to discrepancies in sea ice and sea surface temperature boundary data, which are severely compromised in current reanalyses. Issues with the modeled representation of sea ice cover are an additional factor in reanalysis temperature trends. Differences in the representation of the surface energy budget among the various reanalyses are also reviewed.

Understanding Arctic Surface Temperature Differences in Reanalyses

NASA Technical Reports Server (NTRS)

Cullather, Richard; Zhao, Bin; Shuman, Christopher; Nowicki, Sophie

2017-01-01

Reanalyses in the Arctic are widely used for model evaluation and for understanding contemporary climate change. Nevertheless, differences among reanalyses in fundamental meteorological variables including surface air temperature are large. For example, the 1980-2009 mean surface air temperature for the north polar cap (70ÂdegN-90ÂdegN) among global reanalyses span a range of 2.4 K, which approximates the average warming trend from these reanalyses over the 30-year period of 2.1 K. Understanding these differences requires evaluation over the three principal surface domains of the Arctic: glaciated land, the unglaciated terrestrial surface, and sea ice/ocean. An examination is conducted of contemporary global reanalyses of the ECMWF Interim project, NASA MERRA, MERRA-2, JRA-55, and NOAA CFSR using available in situ data and assessments of the surface energy budget. Overly-simplistic representations of the Greenland Ice Sheet surface are found to be associated with local warm air temperature biases in winter. A review of progress made in the development of the MERRA-2 land-ice representation is presented. Large uncertainty is also found in temperatures over the Arctic tundra and boreal forest zone. But a key focus of temperature differences for northern high latitudes is the Arctic Ocean. Near-surface air temperature differences over the Arctic Ocean are found to be related to discrepancies in sea ice and sea surface temperature boundary data, which are severely compromised in current reanalyses. Issues with the modeled representation of sea ice cover are an additional factor in reanalysis temperature trends. Differences in the representation of the surface energy budget among the various reanalyses are also reviewed.

Improvements to the Noah Land Surface Model in WRF-CMAQ, and its Application to Future Changes in the Chesapeake Bay Region

EPA Science Inventory

Regional, state, and local environmental regulatory agencies often use Eulerian meteorological and air quality models to investigate the potential impacts of climate, emissions, and land use changes on nutrient loading and air quality. The Noah land surface model in WRF could be...

Photomineralization and photomethanification of dissolved organic matter in Saguenay River surface water

NASA Astrophysics Data System (ADS)

Zhang, Y.; Xie, H.

2015-08-01

Rates and apparent quantum yields of photomineralization (AQYDOC) and photomethanification (AQYCH4) of chromophoric dissolved organic matter (CDOM) in Saguenay River surface water were determined at three widely differing dissolved oxygen concentrations ([O2]) (suboxic, air-saturation, and oxygenated) using simulated-solar radiation. Photomineralization increased linearly with CDOM absorbance photobleaching for all three O2 treatments. Whereas the rate of photochemical dissolved organic carbon (DOC) loss increased with increasing [O2], the ratio of fractional DOC loss to fractional absorbance loss showed an inverse trend. CDOM photodegradation led to a nearly complete mineralization under suboxic conditions but to only a partial mineralization under oxic conditions. AQYDOC determined under oxygenated, suboxic, and air-saturated conditions increased, decreased, and remained largely constant with photobleaching, respectively; AQYDOC obtained under air-saturation with short-term irradiations could thus be applied to longer exposures. AQYDOC decreased successively from ultraviolet B (UVB) to ultraviolet A (UVA) to visible (VIS), which, alongside the solar irradiance spectrum, points to VIS and UVA being the primary drivers for photomineralization in the water column. The photomineralization rate in the Saguenay River was estimated to be 2.31 × 108 mol C yr-1, accounting for only 1 % of the annual DOC input into this system. Photoproduction of CH4 occurred under both suboxic and oxic conditions and increased with decreasing [O2], with the rate under suboxic conditions ~ 7-8 times that under oxic conditions. Photoproduction of CH4 under oxic conditions increased linearly with photomineralization and photobleaching. Under air-saturation, 0.00057 % of the photochemical DOC loss was diverted to CH4, giving a photochemical CH4 production rate of 4.36 × 10-6 mol m-2 yr-1 in the Saguenay River and, by extrapolation, of (1.9-8.1) × 108 mol yr-1 in the global ocean. AQYCH4 changed little with photobleaching under air-saturation but increased exponentially under suboxic conditions. Spectrally, AQYCH4 decreased sequentially from UVB to UVA to VIS, with UVB being more efficient under suboxic conditions than under oxic conditions. On a depth-integrated basis, VIS prevailed over UVB in controlling CH4 photoproduction under air-saturation while the opposite held true under O2-deficiency. An addition of micromolar levels of dissolved dimethyl sulfide (DMS) substantially increased CH4 photoproduction, particularly under O2-deficiency; DMS at nanomolar ambient concentrations in surface oceans is, however, unlikely a significant CH4 precursor. Results from this study suggest that CDOM-based CH4 photoproduction only marginally contributes to the CH4 supersaturation in modern surface oceans and to both the modern and Archean atmospheric CH4 budgets, but that the photochemical term can be comparable to microbial CH4 oxidation in modern oxic oceans. Our results also suggest that anoxic microniches in particulate organic matter and phytoplankton cells containing elevated concentrations of precursors of the methyl radical such as DMS may provide potential hotspots for CH4 photoproduction.

Photomineralization and photomethanification of dissolved organic matter in Saguenay River surface water

NASA Astrophysics Data System (ADS)

Zhang, Y.; Xie, H.

2015-11-01

Rates and apparent quantum yields of photomineralization (AQYDOC) and photomethanification (AQYCH4) of chromophoric dissolved organic matter (CDOM) in Saguenay River surface water were determined at three widely differing dissolved oxygen concentrations ([O2]) (suboxic, air saturation, and oxygenated) using simulated-solar radiation. Photomineralization increased linearly with CDOM absorbance photobleaching for all three O2 treatments. Whereas the rate of photochemical dissolved organic carbon (DOC) loss increased with increasing [O2], the ratio of fractional DOC loss to fractional absorbance loss showed an inverse trend. CDOM photodegradation led to a higher degree of mineralization under suboxic conditions than under oxic conditions. AQYDOC determined under oxygenated, suboxic, and air-saturated conditions increased, decreased, and remained largely constant with photobleaching, respectively; AQYDOC obtained under air saturation with short-term irradiations could thus be applied to longer exposures. AQYDOC decreased successively from ultraviolet B (UVB) to ultraviolet A (UVA) to visible (VIS), which, alongside the solar irradiance spectrum, points to VIS and UVA being the primary drivers for photomineralization in the water column. The photomineralization rate in the Saguenay River was estimated to be 2.31 × 108 mol C yr-1, accounting for only 1 % of the annual DOC input into this system. Photoproduction of CH4 occurred under both suboxic and oxic conditions and increased with decreasing [O2], with the rate under suboxic conditions ~ 7-8 times that under oxic conditions. Photoproduction of CH4 under oxic conditions increased linearly with photomineralization and photobleaching. Under air saturation, 0.00057 % of the photochemical DOC loss was diverted to CH4, giving a photochemical CH4 production rate of 4.36 × 10-6 mol m-2 yr-1 in the Saguenay River and, by extrapolation, of (1.9-8.1) × 108 mol yr-1 in the global ocean. AQYCH4 changed little with photobleaching under air saturation but increased exponentially under suboxic conditions. Spectrally, AQYCH4 decreased sequentially from UVB to UVA to VIS, with UVB being more efficient under suboxic conditions than under oxic conditions. On a depth-integrated basis, VIS prevailed over UVB in controlling CH4 photoproduction under air saturation while the opposite held true under O2-deficiency. An addition of micromolar levels of dissolved dimethyl sulfide (DMS) substantially increased CH4 photoproduction, particularly under O2-deficiency; DMS at nanomolar ambient concentrations in surface oceans is, however, unlikely a significant CH4 precursor. Results from this study suggest that CDOM-based CH4 photoproduction only marginally contributes to the CH4 supersaturation in modern surface oceans and to both the modern and Archean atmospheric CH4 budgets, but that the photochemical term can be comparable to microbial CH4 oxidation in modern oxic oceans. Our results also suggest that anoxic microniches in particulate organic matter and phytoplankton cells containing elevated concentrations of precursors of the methyl radical such as DMS may provide potential hotspots for CH4 photoproduction.

Investigation of critical burning of fuel droplets

NASA Technical Reports Server (NTRS)

Allison, C. B.; Canada, G. S.

1972-01-01

Fuel droplets were simulated by porous spheres having diameters in the range 0.63 to 1.9 cm and combustion tests were conducted at pressures up to 78 atm in a quiescent cold air environment. Measurements were made of the burning rate and liquid surface temperature during steady combustion. A high pressure flat flame burner apparatus is under development in order to allow testing of high pressure droplet burning in a combustion gas environment. Work was continued on the high pressure strand combustion characteristics of liquid fuels, with the major emphasis on hydrazine. Data was obtained on the burning rate and liquid surface temperatures at pressures in the range 7 to 500 psia. The response of a burning liquid monopropellant to imposed pressure oscillations is being investigated.

Analysis of The Surface Radiative Budget Using ATLAS Data for San Juan, Puerto Rico

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Rickman, D. L.; Gonzalez, J.; Comarazamy, Daniel; Picon, Ana

2007-01-01

The additional beating of the air over the city is the result of the replacement of naturally vegetated surfaces with those composed of asphalt, concrete, rooftops and other man-made materials. The temperatures of these artificial surfaces can be 20 to 40 C higher than vegetated surfaces. This produces a dome of elevated air temperatures 5 to 8 C greater over the city, compared to the air temperatures over adjacent rural areas. Urban landscapes are a complex mixture of vegetated and nonvegetated surfaces. It is difficult to take enough temperature measurements over a large city area to characterize the complexity of urban radiant surface temperature variability. The NASA Airborne Thermal and Land Applications Sensor (ATLAS) operates in the visual and IR bands was used in February 2004 to collect data from San Juan, Puerto Rico with the main objective of investigating the Urban Heat Island (UHI) in tropical cities.

Mathematical estimation of the level of microbial contamination on spacecraft surfaces by volumetric air sampling

NASA Technical Reports Server (NTRS)

Oxborrow, G. S.; Roark, A. L.; Fields, N. D.; Puleo, J. R.

1974-01-01

Microbiological sampling methods presently used for enumeration of microorganisms on spacecraft surfaces require contact with easily damaged components. Estimation of viable particles on surfaces using air sampling methods in conjunction with a mathematical model would be desirable. Parameters necessary for the mathematical model are the effect of angled surfaces on viable particle collection and the number of viable cells per viable particle. Deposition of viable particles on angled surfaces closely followed a cosine function, and the number of viable cells per viable particle was consistent with a Poisson distribution. Other parameters considered by the mathematical model included deposition rate and fractional removal per unit time. A close nonlinear correlation between volumetric air sampling and airborne fallout on surfaces was established with all fallout data points falling within the 95% confidence limits as determined by the mathematical model.

Study of Vibrational Energy Transfer at a Surface by a Time-of-Flight Method.

DTIC Science & Technology

1983-07-31

82174* - *-. L7 .i.&. I- I OD(D SOI x O 1 6/81 INIT DISTRIBUTION LIST July 31, 1983 No. Copies No. Copies Dr. L.V. Schmidt 1 Dr. F. Roberto 1 Assistant...of Scientific Dr. A.L. Slafkosky 1Research Scientific Advisor Directorate of Aerospace Sciences Commandant of the Marine Corps Bolling Air Force Base...Research Research Code 432 Directorate of Chemical Sciences Arlington, VA 22217 Bolling Air Force Base Washington, D.C. 20332Mr. David SiegelI Office of

MOPAC Manual. A General Molecular Orbital Package. Fourth Edition.

DTIC Science & Technology

1987-10-01

RELEASE; DISTRIBUTION UNLIMITED. / -October 1987 / AIR FORCE SYSTEMS COMMAND / UNITED STATES AIR FORCE - ’,~ 7:I~82 A" A a’ FJSRL-TR-87-0006 This document...will result in a difference in H.o.F. of less than 0.1 Kcal/mole. This is only true for fairly rigid systems , e.g. I- formaldehyde and benzene. For... systems with low barriers to rotation or flat potential surfaces, e.g. aniline or water dimer, quite I large H.o.F. errors can result. *Action users can

3D Air Quality and the Clean Air Interstate Rule: Lagrangian Sampling of CMAQ Model Results to Aid Regional Accountability Metrics

NASA Technical Reports Server (NTRS)

Fairlie, T. D.; Szykman, Jim; Pierce, Robert B.; Gilliland, A. B.; Engel-Cox, Jill; Weber, Stephanie; Kittaka, Chieko; Al-Saadi, Jassim A.; Scheffe, Rich; Dimmick, Fred;

Methods of and apparatus for levitating an eddy current probe

DOEpatents

Stone, William J.

1988-05-03

An eddy current probe is supported against the force of gravity with an air earing while being urged horizontally toward the specimen being examined by a spring and displaced horizontally against the force of the spring pneumatically. The pneumatic displacement is accomplished by flowing air between a plenum chamber fixed with respect to the probe and the surface of the specimen. In this way, the surface of the specimen can be examined without making mechanical contact therewith while precisely controlling the distance at which the probe stands-off from the surface of the specimen.

Respirable crystalline silica exposures during asphalt pavement milling at eleven highway construction sites.

PubMed

Hammond, Duane R; Shulman, Stanley A; Echt, Alan S

2016-07-01

Asphalt pavement milling machines use a rotating cutter drum to remove the deteriorated road surface for recycling. The removal of the road surface has the potential to release respirable crystalline silica, to which workers can be exposed. This article describes an evaluation of respirable crystalline silica exposures to the operator and ground worker from two different half-lane and larger asphalt pavement milling machines that had ventilation dust controls and water-sprays designed and installed by the manufacturers. Manufacturer A completed milling for 11 days at 4 highway construction sites in Wisconsin, and Manufacturer B completed milling for 10 days at 7 highway construction sites in Indiana. To evaluate the dust controls, full-shift personal breathing zone air samples were collected from an operator and ground worker during the course of normal employee work activities of asphalt pavement milling at 11 different sites. Forty-two personal breathing zone air samples were collected over 21 days (sampling on an operator and ground worker each day). All samples were below 50 µg/m(3) for respirable crystalline silica, the National Institute for Occupational Safety and Health recommended exposure limit. The geometric mean personal breathing zone air sample was 6.2 µg/m(3) for the operator and 6.1 µg/m(3) for the ground worker for the Manufacturer A milling machine. The geometric mean personal breathing zone air sample was 4.2 µg/m(3) for the operator and 9.0 µg/m(3) for the ground worker for the Manufacturer B milling machine. In addition, upper 95% confidence limits for the mean exposure for each occupation were well below 50 µg/m(3) for both studies. The silica content in the bulk asphalt material being milled ranged from 7-23% silica for roads milled by Manufacturer A and from 5-12% silica for roads milled by Manufacturer B. The results indicate that engineering controls consisting of ventilation controls in combination with water-sprays are capable of controlling occupational exposures to respirable crystalline silica generated by asphalt pavement milling machines on highway construction sites.

Atmospheric radionuclides from the Fukushima Dai-ichi nuclear reactor accident observed in Vietnam.

PubMed

Long, N Q; Truong, Y; Hien, P D; Binh, N T; Sieu, L N; Giap, T V; Phan, N T

2012-09-01

Radionuclides from the reactor accident at the Fukushima Dai-ichi Nuclear Power Plant were observed in the surface air at stations in Hanoi, Dalat, and Ho Chi Minh City (HCMC) in Vietnam, about 4500 km southwest of Japan, during the period from March 27 to April 22, 2011. The maximum activity concentrations in the air measured at those three sites were 193, 33, and 37 μBq m(-3) for (131)I, (13)(4)Cs, and (13)(7)Cs, respectively. Peaks of radionuclide concentrations in the air corresponded to arrival of the air mass from Fukushima to Vietnam after traveling for 8 d over the Pacific Ocean. Cesium-134 was detected with the (134)Cs/(137)Cs activity ratio of about 0.85 in line with observations made elsewhere. The (131)I/(137)Cs activity ratio was observed to decrease exponentially with time as expected from radioactive decay. The ratio at Dalat, where is 1500 m high, was higher than those at Hanoi and HCMC in low lands, indicating the relative enrichment of the iodine in comparison to cesium at high altitudes. The time-integrated surface air concentrations of the Fukushima-derived radionuclides in the Southeast Asia showed exponential decrease with distance from Fukushima. Copyright © 2011 Elsevier Ltd. All rights reserved.

Central America: A Strategic Imperative.

DTIC Science & Technology

1987-03-01

MAXWELL AIR FORCE BASE, A AMA 87 1 7 2 , o2, 7... , ,. , ,. AIR WAR COLLEGE AIR UNIVERSITY CENTRAL AMERICA: A STRATEGIC IMPERATIVE by a Florian H. Yoste... FORCE BASE, ALABAMA @ i MARCH 1987 ti Acoession For DTIC TAB 0 Utinnounced 0 Justificato-- By Distributionl Availability Codes 7-- Avall and/or ’Dist...College or the Department of the Air Force . This document is the property of the United States Government and is not to be reproduced in whole or in

Assessing the ability of mechanistic volatilization models to simulate soil surface conditions: a study with the Volt'Air model.

PubMed

Garcia, L; Bedos, C; Génermont, S; Braud, I; Cellier, P

2011-09-01

Ammonia and pesticide volatilization in the field is a surface phenomenon involving physical and chemical processes that depend on the soil surface temperature and water content. The water transfer, heat transfer and energy budget sub models of volatilization models are adapted from the most commonly accepted formalisms and parameterizations. They are less detailed than the dedicated models describing water and heat transfers and surface status. The aim of this work was to assess the ability of one of the available mechanistic volatilization models, Volt'Air, to accurately describe the pedo-climatic conditions of a soil surface at the required time and space resolution. The assessment involves: (i) a sensitivity analysis, (ii) an evaluation of Volt'Air outputs in the light of outputs from a reference Soil-Vegetation-Atmosphere Transfer model (SiSPAT) and three experimental datasets, and (iii) the study of three tests based on modifications of SiSPAT to establish the potential impact of the simplifying assumptions used in Volt'Air. The analysis confirmed that a 5 mm surface layer was well suited, and that Volt'Air surface temperature correlated well with the experimental measurements as well as with SiSPAT outputs. In terms of liquid water transfers, Volt'Air was overall consistent with SiSPAT, with discrepancies only during major rainfall events and dry weather conditions. The tests enabled us to identify the main source of the discrepancies between Volt'Air and SiSPAT: the lack of gaseous water transfer description in Volt'Air. They also helped to explain why neither Volt'Air nor SiSPAT was able to represent lower values of surface water content: current classical water retention and hydraulic conductivity models are not yet adapted to cases of very dry conditions. Given the outcomes of this study, we discuss to what extent the volatilization models can be improved and the questions they pose for current research in water transfer modeling and parameterization. Copyright © 2011 Elsevier B.V. All rights reserved.

Early and long-term mantle processing rates derived from xenon isotopes

NASA Astrophysics Data System (ADS)

Mukhopadhyay, S.; Parai, R.; Tucker, J.; Middleton, J. L.; Langmuir, C. H.

2015-12-01

Noble gases, particularly xenon (Xe), in mantle-derived basalts provide a rich portrait of mantle degassing and surface-interior volatile exchange. The combination of extinct and extant radioactive species in the I-Pu-U-Xe systems shed light on the degassing history of the early Earth throughout accretion, as well as the long-term degassing of the Earth's interior in association with plate tectonics. The ubiquitous presence of shallow-level air contamination, however, frequently obscures the mantle Xe signal. In a majority of the samples, shallow air contamination dominates the Xe budget. For example, in the gas-rich popping rock 2ΠD43, 129Xe/130Xe ratios reach 7.7±0.23 in individual step-crushes, but the bulk composition of the sample is close to air (129Xe/130Xe of 6.7). Thus, the extent of variability in mantle source Xe composition is not well-constrained. Here, we present new MORB Xe data and explore constraints placed on mantle processing rates by the Xe data. Ten step-crushes were obtained on a depleted popping glass that was sealed in ultrapure N2 after dredge retrieval from between the Kane-Atlantis Fracture Zone of the Mid Atlantic Ridge in May 2012. 9 steps yielded 129Xe/130Xe of 7.50-7.67 and one yielded 7.3. The bulk 129Xe/130Xe of the sample is 7.6, nearly identical to the estimated mantle source value of 7.7 for the sample. Hence, the sample is virtually free of shallow-level air contamination. Because sealing the sample in N2upon dredge retrieval largely eliminated air contamination, for many samples, contamination must be added after sample retrieval from the ocean bottom. Our new high-precision Xe isotopic measurements in upper mantle-derived samples provide improved constraints on the Xe isotopic composition of the mantle source. We developed a forward model of mantle volatile evolution to identify solutions that satisfy our Xe isotopic data. We find that accretion timescales of ~10±5 Myr are consistent with I-Pu-Xe constraints, and the last giant impact occurred 45-70 Myr after the start of the solar system. After the giant impact stage, the Pu-U-Xe system indicates that degassing of the planet via solid-state mantle convection and plate tectonics continued to liberate volatiles to the atmosphere and has led to between ~5-8 mantle turnovers over the age of the Earth.

Design and analysis of Air flow duct for improving the thermal performance of disc brake rotor

NASA Astrophysics Data System (ADS)

Raja, T.; Mathiselvan, G.; Sreenivasulureddy, M.; Goldwin Xavier, X.

2017-05-01

safety in automotive engineering has been considered as a number one priority in development of new vehicle. A brake system is one of the most critical systems in the vehicle, without which the vehicle will put a passenger in an unsafe position. Temperature distribution on disc rotor brake and the performance brake of disc rotor is influenced by the air flow around the disc rotor. In this paper, the effect of air flow over the disc rotor is analyzed using the CFD software. The air flow over the disc rotor is increased by using a duct to supply more air flow over the disc rotor. The duct is designed to supply more air to the rotor surface and it can be placed in front of the vehicle for better performance. Increasing the air flow around the rotor will maximize the heat convection from the rotor surface. The rotor life and the performance can be improved.

Comparison of forced-air warming systems with upper body blankets using a copper manikin of the human body.

PubMed

Bräuer, A; English, M J M; Steinmetz, N; Lorenz, N; Perl, T; Braun, U; Weyland, W

2002-09-01

Forced-air warming with upper body blankets has gained high acceptance as a measure for the prevention of intraoperative hypothermia. However, data on heat transfer with upper body blankets are not yet available. This study was conducted to determine the heat transfer efficacy of eight complete upper body warming systems and to gain more insight into the principles of forced-air warming. Heat transfer of forced-air warmers can be described as follows: Qdot;=h. DeltaT. A, where Qdot;= heat flux [W], h=heat exchange coefficient [W m-2 degrees C-1], DeltaT=temperature gradient between the blanket and surface [ degrees C], and A=covered area [m2]. We tested eight different forced-air warming systems: (1) Bair Hugger and upper body blanket (Augustine Medical Inc. Eden Prairie, MN); (2) Thermacare and upper body blanket (Gaymar Industries, Orchard Park, NY); (3) Thermacare (Gaymar Industries) with reusable Optisan upper body blanket (Willy Rüsch AG, Kernen, Germany); (4) WarmAir and upper body blanket (Cincinnati Sub-Zero Products, Cincinnati, OH); (5) Warm-Gard and single use upper body blanket (Luis Gibeck AB, Upplands Väsby, Sweden); (6) Warm-Gard and reusable upper body blanket (Luis Gibeck AB); (7) WarmTouch and CareDrape upper body blanket (Mallinckrodt Medical Inc., St. Luis, MO); and (8) WarmTouch and reusable MultiCover trade mark upper body blanket (Mallinckrodt Medical Inc.) on a previously validated copper manikin of the human body. Heat flux and surface temperature were measured with 11 calibrated heat flux transducers. Blanket temperature was measured using 11 thermocouples. The temperature gradient between the blanket and surface (DeltaT) was varied between -8 and +8 degrees C, and h was determined by linear regression analysis as the slope of DeltaT vs. heat flux. Mean DeltaT was determined for surface temperatures between 36 and 38 degrees C, as similar mean skin surface temperatures have been found in volunteers. The covered area was estimated to be 0.35 m2. Total heat flow from the blanket to the manikin was different for surface temperatures between 36 and 38 degrees C. At a surface temperature of 36 degrees C the heat flows were higher (4-26.6 W) than at surface temperatures of 38 degrees C (2.6-18.1 W). The highest total heat flow was delivered by the WarmTouch trade mark system with the CareDrape trade mark upper body blanket (18.1-26.6 W). The lowest total heat flow was delivered by the Warm-Gard system with the single use upper body blanket (2.6-4 W). The heat exchange coefficient varied between 15.1 and 36.2 W m-2 degrees C-1, and mean DeltaT varied between 0.5 and 3.3 degrees C. We found total heat flows of 2.6-26.6 W by forced-air warming systems with upper body blankets. However, the changes in heat balance by forced-air warming systems with upper body blankets are larger, as these systems are not only transferring heat to the body but are also reducing heat losses from the covered area to zero. Converting heat losses of approximately 37.8 W to heat gain, results in a 40.4-64.4 W change in heat balance. The differences between the systems result from different heat exchange coefficients and different mean temperature gradients. However, the combination of a high heat exchange coefficient with a high mean temperature gradient is rare. This fact offers some possibility to improve these systems.

SU-E-T-352: Effects of Skull Attenuation and Missing Backscatter On Brain Dose in HDR Treatment of the Head with Surface Applicators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cifter, F; Dhou, S; Lewis, J

2015-06-15

Purpose: To calculate the effect of lack of backscatter from air and attenuation of bone on dose distributions in brachytherapy surface treatment of head. Existing treatment planning systems based on TG43 do not account for heterogeneities, and thus may overestimate the dose to the brain. While brachytherapy generally has rapid dose falloff, the dose to the deeper tissues (in this case, the brain) can become significant when treating large curved surfaces. Methods: Applicator geometries representing a range of clinical cases were simulated in MCNP5. An Ir-192 source was modeled using the energy spectrum presented by TG-43. The head phantom wasmore » modeled as a 7.5-cm radius water sphere, with a 7 -mm thick skull embedded 5-mm beneath the surface. Dose values were calculated at 20 points inside the head, in which 10 of them were on the central axis and the other 10 on the axis connecting the central of the phantom with the second to last source from the applicator edge. Results: Central and peripheral dose distributions for a range of applicator and head sizes are presented. The distance along the central axis at which the dose falls to 80% of the prescribed dose (D80) was 7 mm for a representative small applicator and 9 mm for a large applicator. Corresponding D50 and D30 for the same small applicator were 17 mm and 32 mm respectively. D50 and D30 for the larger applicator were 32 mm and 60 mm respectively. These results reflect the slower falloff expected for larger applicators on a curved surface. Conclusion: Our results can provide guidance for clinicians to calculate the dose reduction effect due to bone attenuation and the lack of backscatter from air to estimate the brain dose for the HDR treatments of surface lesions.« less

Inter-comparison between AIRS and IASI through Retrieved Parameters

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Larar, Allen M.; Smith, William L.; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Steve

2008-01-01

A State-of-the-art retrieval algorithm dealing with all-weather conditions has been applied to satellite/aircraft instruments retrieving cloud/surface and atmospheric conditions. High quality retrievals have been achieved from IASI data. Surface, cloud, and atmospheric structure and variation are well captured by IASI measurements and/or retrievals. The same retrieval algorithm is also applied to AIRS for retrieval inter-comparison. Both AIRS and IASI have a similar FOV size but AIRS has a higher horizontal resolution. AIRS data can be interpolated to IASI horizontal resolution for inter-comparison at the same geophysical locations, however a temporal variation between AIRS and IASI observations need to be considered. JAIVEx has employed aircraft to obtain the atmospheric variation filling the temporal gap between two satellites. First results show that both AIRS and IASI have a very similar vertical resolving power, atmospheric conditions are well captured by both instruments, and radiances are well calibrated. AIRS data shown in retrievals (e.g., surface emissivity and moisture) have a relatively higher noise level. Since the this type of retrieval is very sensitive to its radiance quality, retrieval products inter-comparison is an effective way to identify/compare their radiance quality, in terms of a combination of spectral resolution and noise level, and to assess instrument performance. Additional validation analyses are needed to provide more-definitive conclusions.

Research on Spent Fuel Storage and Transportation in CRIEPI (Part 2 Concrete Cask Storage)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koji Shirai; Jyunichi Tani; Taku Arai

2008-10-01

Concrete cask storage has been implemented in the world. At a later stage of storage period, the containment of the canister may deteriorate due to stress corrosion cracking phenomena in a salty air environment. High resistant stainless steels against SCC have been tested as compared with normal stainless steel. Taking account of the limited time-length of environment with certain level of humidity and temperature range, the high resistant stainless steels will survive from SCC damage. In addition, the adhesion of salt from salty environment on the canister surface will be further limited with respect to the canister temperature and anglemore » of the canister surface against the salty air flow in the concrete cask. Optional countermeasure against SCC with respect to salty air environment has been studied. Devices consisting of various water trays to trap salty particles from the salty air were designed to be attached at the air inlet for natural cooling of the cask storage building. Efficiency for trapping salty particles was evaluated. Inspection of canister surface was carried out using an optical camera inserted from the air outlet through the annulus of a concrete cask that has stored real spent fuel for more than 15 years. The camera image revealed no gross degradation on the surface of the canister. Seismic response of a full-scale concrete cask with simulated spent fuel assemblies has been demonstrated. The cask did not tip over, but laterally moved by the earthquake motion. Stress generated on the surface of the spent fuel assemblies during the earthquake motion were within the elastic region.« less

Mechano-regulated surface for manipulating liquid droplets

NASA Astrophysics Data System (ADS)

Tang, Xin; Zhu, Pingan; Tian, Ye; Zhou, Xuechang; Kong, Tiantian; Wang, Liqiu

2017-04-01

The effective transfer of tiny liquid droplets is vital for a number of processes such as chemical and biological microassays. Inspired by the tarsi of meniscus-climbing insects, which can climb menisci by deforming the water/air interface, we developed a mechano-regulated surface consisting of a background mesh and a movable microfibre array with contrastive wettability. The adhesion of this mechano-regulated surface to liquid droplets can be reversibly switched through mechanical reconfiguration of the microfibre array. The adhesive force can be tuned by varying the number and surface chemistry of the microfibres. The in situ adhesion of the mechano-regulated surface can be used to manoeuvre micro-/nanolitre liquid droplets in a nearly loss-free manner. The mechano-regulated surface can be scaled up to handle multiple droplets in parallel. Our approach offers a miniaturized mechano-device with switchable adhesion for handling micro-/nanolitre droplets, either in air or in a fluid that is immiscible with the droplets.

Observations of the microclimate of a lake under cold air advective conditions

NASA Technical Reports Server (NTRS)

Bill, R. G., Jr.; Sutherland, R. A.; Bartholic, J. F.

1977-01-01

The moderating effects of Lake Apopka, Florida, on downwind surface temperatures were evaluated under cold air advective conditions. Point temperature measurements north and south of the lake and data obtained from the NOAA satellite and a thermal scanner flown at 1.6 km, indicate that, under conditions of moderate winds (approximately 4m/sec), surface temperatures directly downwind may be higher than surrounding surface temperatures by as much as 5 C. With surface wind speed less than 1m/sec, no substantial temperature effects were observed. Results of this study are being used in land use planning, lake level control and in agriculture for selecting planting sites.

Environmental Impact Analysis Process. Volume 1. Preliminary Draft Environmental Impact Statement Construction and Operation of Space Launch Complex 7, Vandenberg Air Force Base, California

DTIC Science & Technology

1989-04-06

Cfiada Agua Viva is a south-flowing, perennial drainage located east of the project area and fed by two springs near Wild Horse Flats. Perennial yields...from this drainage are expected to be less than five gallons per minute (gpm), or 60 acre-feet per year. Caflada Agua Viva has a watershed area of... Agua Viva drainages are shown in Table 3.2.1 (Surface Water Quality, Point Arguello Area). Notably high values of total hardness, specific

The Tropospheric cooling and the Stratospheric warming at Tirunelveli during the Annular Solar Eclipse of 15 January, 2010

NASA Astrophysics Data System (ADS)

Nelli, Narendra Reddy; Choudhary, Raj Kumar; Rao, Kusuma

The UTLS region, a transition region between the troposphere and the stratosphere is of concern to climate scientists as its temperature variations are crucial in determining the water vapour and the other trace gases transport between the two regions, which inturn determine the radiative warming and cooling of the troposphere and the stratosphere. To examine, the temperature variations from surface to lower stratosphere,a major experiment facility was set up for upper air and surface measurements during the Annular Solar Eclipse (ASE) of January 15, 2010 at Tirunelveli (8.72 N, 77.81 E) located in 94% eclipse path in the southern peninsular India. The instruments,namely, 1. high resolution GPS radiosonde system, 2. an instrumented 15 m high Mini Boundary Layer Mast, 3. an instrumented 1 m high Near Surface Mast (NSM), radiation and other ground sensors were operated during the period 14-19 Jan, 2010. The ASE of January 15, 2010 was unique being the longest in duration (9 min, 15.3 sec) among the similar ones that occurred in the past. The major inference from an analysis of surface and upper air measurements is the occurrence of troposphere cooling during the eclipse with the peak cooling of 5 K at 15 km height with respect to no-eclispe conditions. Also, intense warming in the stratosphere is observed with the peak warming of 7 K at 19 km height.Cooling of the Troposphere as the eclipse advanced and the revival to its normal temperature is clearly captured in upper air measurements. The downward vertical velocities observed at 100 hPa in NCEP Re-analyses, consistent with the tropospheric cooling during the ASE window, may be causing the stratospheric warming. Partly, these vertical velocities could be induced by the mesoscale circulation associated with the mesoscale convective system that prevailed parallel to the eclipse path as described in METEOSAT imageries of brightness temperatures from IR channel. Further analysis is being carried out to quantify the variations in turbulent parameters during ASE window using the high resolution GPS Radiosonde data.

Background ozone in North China: trends, photochemical and transport impacts

NASA Astrophysics Data System (ADS)

Xu, X.; Lin, W.; Ge, B.

2011-12-01

Tropospheric ozone is one of the key greenhouse gases and plays an important role in atmospheric chemistry. Being a strong oxidant, ozone in the surface layer has significant impacts on human and vegetation health. Long-term measurements of surface ozone are highly needed for climate change assessment and environmental policy-making. Such measurements are scarce, particularly from the background regions. Since 2004, surface ozone and some related reactive gases have been observed at Shangdianzi (SDZ), a Global Atmosphere Watch (GAW) station in North China. Located at the north edge of the Northern China Plain (NCP), the SDZ station is an ideal site for capturing polluted air masses from the NCP sector (southwest) and clean air masses from the background sector (northeast). This facilitates the investigation of impacts of regional transport on surface ozone. In this study, we present long-term measurements of surface ozone made at SDZ, discuss the trends of surface ozone levels in different seasons. Results about the observation-based ozone production efficiency (OPE) for the site will be presented, along with impacts from horizontal and vertical air transport.

Background ozone in North China: trends, photochemical and transport impacts

NASA Astrophysics Data System (ADS)

Xu, X.; Lin, W.; Ge, B.

2012-04-01

Tropospheric ozone is one of the key greenhouse gases and plays an important role in atmospheric chemistry. Being a strong oxidant, ozone in the surface layer has significant impacts on human and vegetation health. Long-term measurements of surface ozone are highly needed for climate change assessment and environmental policy-making. Such measurements are scarce, particularly from the background regions. Since 2004, surface ozone and some related reactive gases have been observed at Shangdianzi (SDZ), a Global Atmosphere Watch (GAW) station in North China. Located at the north edge of the Northern China Plain (NCP), the SDZ station is an ideal site for capturing polluted air masses from the NCP sector (southwest) and clean air masses from the background sector (northeast). This facilitates the investigation of impacts of regional transport on surface ozone. In this study, we present long-term measurements of surface ozone made at SDZ, discuss the trends of surface ozone levels in different seasons. Results about the observation-based ozone production efficiency (OPE) for the site will be presented, along with impacts from horizontal and vertical air transport.

Reflector for efficient coupling of a laser beam to air or other fluids

DOEpatents

Kare, Jordin T.

1992-01-01

A reflector array is disclosed herein that provides a controlled region or regions of plasma breakdowns from a laser beam produced at a remotely-based laser source. The plasma may be applied to produce thrust to propel a spacecraft, or to diagnose a laser beam, or to produce shockwaves. The spacecraft propulsion system comprises a reflector array attached to the vehicle. The reflector array comprises a plurality of reflectors spaced apart on a reflective surface, with each reflector acting as an independent focusing mirror. The reflectors are spaced closely together to form a continuous or partially-continuous surface. The reflector array may be formed from a sheet of reflective material, such as copper or aluminum. In operation, a beam of electromagnetic energy, such as a laser beam, is directed at the reflectors which focus the reflected electromagnetic energy at a plurality of regions off the surface. The energy concentrated in the focal region causes a breakdown of the air or other fluid in the focal region, creating a plasma. Electromagnetic energy is absorbed in the plasma and it grows in volume, compressing and heating the adjacent fluid thereby providing thrust. Laser pulses may be applied repetitively. After each such thrust pulse, fresh air can be introduced next to the surface either laterally, or through a perforated surface. If air or some other gas or vapor is supplied, for example from a tank carried on board a vehicle, this invention may also be used to provide thrust in a vacuum environment.

Periodic striations on beryllium and tungsten surfaces by indirect femtosecond laser irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lungu, C. P.; Ticoş, C. M., E-mail: catalin.ticos@inflpr.ro; Poroşnicu, C.

2014-03-10

Femtosecond laser pulses with λ = 800 nm were focused in air at one atmosphere and in deuterium (D) at low pressure. Submicron periodic structures were observed on surfaces made of Be, W and a mixture of Be-W immersed in these gases and placed nearly parallel with the laser beam, at 300 μm from the focal spot. In air, no structures were observed on Be. For the Be-W mixture, the periodic structures were uniform and parallel when formed in D but irregular in air. In this last case the striations were organized into small patches of 1 to 2 μm in size.

Paint and Surface Preparation Training Program for Shipyard Personnel

DTIC Science & Technology

1979-01-01

major anti- fouling ingredient in the various coatings which are used on shipbottoms -- bituminous, vinyl, and chlorinated rubber. Organotin compounds ...Improper cleaning of surface or spray gun; dirty work area. Remedy: In most cases, sanding and recoating is sufficient. Blasting may be indicated in... compounds . When using air-fed respirators, the source of air must be monitored and controlled. It must meet specifications defining cleanliness and minimal

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.

External tank chill effect on the space transportation system launch pad environment

NASA Technical Reports Server (NTRS)

Ahmad, R. A.; Boraas, S.

1991-01-01

The external tank (ET) of the STS contains liquid oxygen and liquid hydrogen as oxidizer and fuel for the SSMEs. Once the cryogen have been loaded into the ET, the temperature of the air surrounding the STS is chilled by the cold outer surface of the ET. This paper describes a two-dimensional flow and thermal analysis to determine this chill effect on the STS launch pad environment subsequent to the ET loading operation. The analysis was done assuming winter conditions and a northwest wind direction. An existing CFD code, PHOENICS '81, was used in the study. The results are presented as local and average values of the heat transfer coefficient, the Nusselt number, and the surface temperature around the redesigned solid rocket motors (RSRMs) and the ET. The temperature depression caused by the ET chilling of the air in the vicinity of the RSRMs was calculated to be 3 F below the ambient. This compares with the observed 1-2 F RSRM surface temperature depression based upon measurements made prior to the winter flight of STS-29. Since the surface temperature would be expected to be slightly higher than the local air temperature, the predicted temperature depression of the air appears to be substantiated.

30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Test to determine the maximum fuel-air ratio. 7... Use in Underground Coal Mines § 7.87 Test to determine the maximum fuel-air ratio. (a) Test procedure... range that will be used during this test. (3) While running the engine, the following shall apply: (i...

30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test to determine the maximum fuel-air ratio. 7... Use in Underground Coal Mines § 7.87 Test to determine the maximum fuel-air ratio. (a) Test procedure... range that will be used during this test. (3) While running the engine, the following shall apply: (i...

30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Test to determine the maximum fuel-air ratio. 7... Use in Underground Coal Mines § 7.87 Test to determine the maximum fuel-air ratio. (a) Test procedure... range that will be used during this test. (3) While running the engine, the following shall apply: (i...

30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Test to determine the maximum fuel-air ratio. 7... Use in Underground Coal Mines § 7.87 Test to determine the maximum fuel-air ratio. (a) Test procedure... range that will be used during this test. (3) While running the engine, the following shall apply: (i...

30 CFR 7.87 - Test to determine the maximum fuel-air ratio.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Test to determine the maximum fuel-air ratio. 7... Use in Underground Coal Mines § 7.87 Test to determine the maximum fuel-air ratio. (a) Test procedure... range that will be used during this test. (3) While running the engine, the following shall apply: (i...

Surface Map Traffic Intent Displays and Net-Centric Data-link Communications for NextGen

NASA Technical Reports Server (NTRS)

Shelton, Kevin J.; Prinzel, Lawrence J., III; Jones, Denise R.; Allamandola, Angela S.; Arthur, Jarvis J., III; Bailey, Randall E.

2009-01-01

By 2025, U.S. air traffic is predicted to increase three fold and may strain the current air traffic management system, which may not be able to accommodate this growth. In response to this challenge, a revolutionary new concept has been proposed for U.S. aviation operations, termed the Next Generation Air Transportation System or "NextGen". Many key capabilities are being identified to enable NextGen, including the use of data-link communications. Because NextGen represents a radically different approach to air traffic management and requires a dramatic shift in the tasks, roles, and responsibilities for the flight deck, there are numerous research issues and challenges that must be overcome to ensure a safe, sustainable air transportation system. Flight deck display and crew-vehicle interaction concepts are being developed that proactively investigate and overcome potential technology and safety barriers that might otherwise constrain the full realization of NextGen. The paper describes simulation research, conducted at National Aeronautics and Space Administration (NASA) Langley Research Center, examining data-link communications and traffic intent data during envisioned four-dimensional trajectory (4DT)-based and equivalent visual (EV) surface operations. Overall, the results suggest that controller pilot data-link communications (CPDLC) with the use of mandatory pilot read-back of all clearances significantly enhanced situation awareness for 4DT and EV surface operations. The depiction of graphical traffic state and intent information on the surface map display further enhanced off-nominal detection and pilot qualitative reports of safety and awareness.

Comparing and evaluating model estimates of background ozone in surface air over North America

NASA Astrophysics Data System (ADS)

Oberman, J.; Fiore, A. M.; Lin, M.; Zhang, L.; Jacob, D. J.; Naik, V.; Horowitz, L. W.

2011-12-01

Tropospheric ozone adversely affects human health and vegetation, and is thus a criteria pollutant regulated by the U.S. Environmental Protection Agency (EPA) under the National Ambient Air Quality Standard (NAAQS). Ozone is produced in the atmosphere via photo-oxidation of volatile organic compounds (VOCs) and carbon monoxide (CO) in the presence of nitrogen oxides (NOx). The present EPA approach considers health risks associated with exposure to ozone enhancement above the policy-relevant background (PRB), which is currently defined as the surface concentration of ozone that would exist without North American anthropogenic emissions. PRB thus includes production by natural precursors, production by precursors emitted on foreign continents, and transport of stratospheric ozone into surface air. As PRB is not an observable quantity, it must be estimated using numerical models. We compare PRB estimates for the year 2006 from the GFDL Atmospheric Model 3 (AM3) chemistry-climate model (CCM) and the GEOS-Chem (GC) chemical transport model (CTM). We evaluate the skill of the models in reproducing total surface ozone observed at the U.S. Clean Air Status and Trends Network (CASTNet), dividing the stations into low-elevation (< 1.5 km in altitude, primarily eastern) and high-elevation (> 1.5 km in altitude, all western) subgroups. At the low-elevation sites AM3 estimates of PRB (38±9 ppbv in spring, 27±9 ppbv in summer) are higher than GC (27±7 ppbv in spring, 21±8 ppbv in summer) in both seasons. Analysis at these sites is complicated by a positive bias in AM3 total ozone with respect to the observed total ozone, the source of which is yet unclear. At high-elevation sites, AM3 PRB is higher in the spring (47±8 ppbv) than in the summer (33±8 ppbv). In contrast, GC simulates little seasonal variation at high elevation sites (39±5 ppbv in spring vs. 38±7 ppbv in summer). Seasonal average total ozone at these sites was within 4 ppbv of the observations for both spring and summer in both models. The high elevation springtime maximum in PRB predicted by AM3 likely reflects stronger exchange between the surface and the free troposphere relative to GC, including a larger influence of stratospheric ozone. Higher summertime PRB in GC may be associated with differences in how the models treat the lightning NOx source (~10 times higher in GC over the Southwest U.S.). Biomass burning emissions (treated differently in the two models) contribute to episodic PRB enhancements in AM3 over the Midwest and East Coast. We conclude that further multi-model studies, including additional models, could provide the EPA with a more robust estimate of PRB, particularly if designed to isolate the relative roles of emissions, chemistry and transport, and evaluated with observation-based constraints wherever possible.

Radon daughter disequilibria and lead systematics in the western North Atlantic

NASA Astrophysics Data System (ADS)

Hussain, N.; Church, T. M.; VéRon, Alain J.; Larson, R. E.

1998-01-01

Concentrations of 222Rn and 210Pb were measured in the North Atlantic troposphere in 1989 between April 12 and 28, during the Sulfide Experiment (SEX) Cruise I, and those of 222Rn, 210Pb and 210Po, between October 24 and November 9, during the SEX Cruise II. Concentrations of 210Pb and 210Po were also measured in the rain water, surface seawater, and marine microlayer collected during the SEX Cruise II Other data used and published previously include stable lead and its isotopes [Vèron et al., 1992, 1993] on parallel samples. Low 222Rn contents, of the order of 0.1 and 0.3 Bq m-3, were found in the marine air, while continental air showed nearly 10 times higher concentrations of 222Rn. These results corroborate with the air mass trajectory analyses and continental signatures of stable lead isotopes. Significant correlation is found between 222Rn and 210Pb on the aerosol, indicative of excess continental 222Rn supporting the ingrowth of 210Pb from the atmosphere, in spite of its first-order removal by precipitation. Correlation between 210Pb and stable Pb on the aerosol and in the precipitation document the source of pollutant lead from the continental surface. Mean residence times of marine aerosol based on 210Pb is estimated to be 5.4±1.8 days during the April cruise and 19.7±1.9 days during the October cause. Corresponding deposition velocity for 210Pb is estimated to be 1.9±1.9 cm s-1, a value that suggests the dominant role of precipitation scavenging, or aerosol scavenging by larger host phases such as dust or sea salt. Excess 210Po activities are found on the aerosol relative to what would be expected based on 210Pb and the aerosol residence times. In surface seawaters, deficiencies of 210Po are observed. Mechanisms of 210Po enrichment in atmospheric aerosol may include enrichments from the organic components of marine microlayer, sea-salt aerosol, dust, or air-sea exchange of volatile organo-polonium species.

Ultra-smooth finishing of aspheric surfaces using CAST technology

NASA Astrophysics Data System (ADS)

Kong, John; Young, Kevin

2014-06-01

Growing applications for astronomical ground-based adaptive systems and air-born telescope systems demand complex optical surface designs combined with ultra-smooth finishing. The use of more sophisticated and accurate optics, especially aspheric ones, allows for shorter optical trains with smaller sizes and a reduced number of components. This in turn reduces fabrication and alignment time and costs. These aspheric components include the following: steep surfaces with large aspheric departures; more complex surface feature designs like stand-alone off-axis-parabola (OAP) and free form optics that combine surface complexity with a requirement for ultra-high smoothness, as well as special optic materials such as lightweight silicon carbide (SiC) for air-born systems. Various fabrication technologies for finishing ultra-smooth aspheric surfaces are progressing to meet these growing and demanding challenges, especially Magnetorheological Finishing (MRF) and ion-milling. These methods have demonstrated some good success as well as a certain level of limitations. Amongst them, computer-controlled asphere surface-finishing technology (CAST), developed by Precision Asphere Inc. (PAI), plays an important role in a cost effective manufacturing environment and has successfully delivered numerous products for the applications mentioned above. One of the most recent successes is the Gemini Planet Imager (GPI), the world's most powerful planet-hunting instrument, with critical aspheric components (seven OAPs and free form optics) made using CAST technology. GPI showed off its first images in a press release on January 7, 2014 . This paper reviews features of today's technologies in handling the ultra-smooth aspheric optics, especially the capabilities of CAST on these challenging products. As examples, three groups of aspheres deployed in astronomical optics systems, both polished and finished using CAST, will be discussed in detail.

Air sampling procedures to evaluate microbial contamination: a comparison between active and passive methods in operating theatres.

PubMed

Napoli, Christian; Marcotrigiano, Vincenzo; Montagna, Maria Teresa

2012-08-02

Since air can play a central role as a reservoir for microorganisms, in controlled environments such as operating theatres regular microbial monitoring is useful to measure air quality and identify critical situations. The aim of this study is to assess microbial contamination levels in operating theatres using both an active and a passive sampling method and then to assess if there is a correlation between the results of the two different sampling methods. The study was performed in 32 turbulent air flow operating theatres of a University Hospital in Southern Italy. Active sampling was carried out using the Surface Air System and passive sampling with settle plates, in accordance with ISO 14698. The Total Viable Count (TVC) was evaluated at rest (in the morning before the beginning of surgical activity) and in operational (during surgery). The mean TVC at rest was 12.4 CFU/m3 and 722.5 CFU/m2/h for active and passive samplings respectively. The mean in operational TVC was 93.8 CFU/m3 (SD = 52.69; range = 22-256) and 10496.5 CFU/m2/h (SD = 7460.5; range = 1415.5-25479.7) for active and passive samplings respectively. Statistical analysis confirmed that the two methods correlate in a comparable way with the quality of air. It is possible to conclude that both methods can be used for general monitoring of air contamination, such as routine surveillance programs. However, the choice must be made between one or the other to obtain specific information.

Laser Radiation-Induced Air Breakdown And Plasma Shielding

NASA Astrophysics Data System (ADS)

Smith, David C.

1981-12-01

Gas breakdown, or the ionization of the air in the path of a high power laser, is a limit on the maximum intensity which can be propagated through the atmosphere. When the threshold for breakdown is exceeded, a high density, high temperature plasma is produced which is opaque to visible and infrared wavelengths and thus absorbs the laser radiation. The threshold in the atmosphere is significantly lower than in pure gases because of laser interaction and vaporization of aerosols. This aspect of air breakdown is discussed in detail. Parametric studies have revealed the scaling laws of breakdown as to wavelength and laser pulse duration, and these will be discussed and compared with existing models. A problem closely related to breakdown is the plasma produc-tion when a high intensity laser interacts with a surface. In this case, the plasma can be beneficial for coupling laser energy into shiny surfaces. The plasma absorbs the laser radiation and reradiates the energy at shorter wavelengths; this shorter wavelength radiation is absorbed by the surface, thus increasing the coupling of energy into the surface. The conditions for the enhancement of laser coupling into surfaces will be discussed, particularly for cw laser beams, an area of recent experimen-tal investigation.

Hand-held portable desorption atmospheric pressure chemical ionization ion source for in situ analysis of nitroaromatic explosives.

PubMed

Jjunju, Fred P M; Maher, Simon; Li, Anyin; Syed, Sarfaraz U; Smith, Barry; Heeren, Ron M A; Taylor, Stephen; Cooks, R Graham

2015-10-06

A novel, lightweight (0.6 kg), solvent- and gas-cylinder-free, hand-held ion source based on desorption atmospheric pressure chemical ionization has been developed and deployed for the analysis of nitroaromatic explosives on surfaces in open air, offering portability for in-field analysis. A small, inexpensive, rechargeable lithium polymer battery was used to power the custom-designed circuitry within the device, which generates up to ±5 kV dc voltage to ignite a corona discharge plasma in air for up to 12 h of continuous operation, and allowing positive- and negative-ion mass spectrometry. The generated plasma is pneumatically transported to the surface to be interrogated by ambient air at a rate of 1-3.5 L/min, compressed using a small on-board diaphragm pump. The plasma source allows liquid or solid samples to be examined almost instantaneously without any sample preparation in the open environment. The advantages of low carrier gas and low power consumption (<6 W), as well as zero solvent usage, have aided in developing the field-ready, hand-held device for trigger-based, "near-real-time" sampling/ionization. Individual nitroaromatic explosives (such as 2,4,6-trinitrotoluene) can be easily detected in amounts as low as 5.8 pg with a linear dynamic range of at least 10 (10-100 pg), a relative standard deviation of ca. 7%, and an R(2) value of 0.9986. Direct detection of several nitroaromatic compounds in a complex mixture without prior sample preparation is demonstrated, and their identities are confirmed by tandem mass spectrometry fragmentation patterns.

Critical analysis of the condensation of water vapor at external surface of the duct

NASA Astrophysics Data System (ADS)

Kumar, Dileep; Memon, Rizwan Ahmed; Memon, Abdul Ghafoor; Ali, Intizar; Junejo, Awais

2018-01-01

In this paper, the effects of contraction of the insulation of the air duct of heating, ventilation, and air conditioning (HVAC) system is investigated. The compression of the insulation contracts it at joint, turn and other points of the duct. The energy loss and the condensation resulted from this contraction are also estimated. A mathematical model is developed to simulate the effects of this contraction on the heat gain, supply air temperature and external surface temperature of the duct. The simulation uses preliminary data obtained from an HVAC system installed in a pharmaceutical company while varying the operating conditions. The results reveal that insulation thickness should be kept greater than 30 mm and the volume flow rate of the selected air distribution system should be lower than 1.4m3/s to subside condensation on the external surface of the duct. Additionally, the optimum insulation thickness was determined by considering natural gas as an energy source and fiberglass as an insulation material. The optimum insulation thickness determined for different duct sizes varies from 28 to 45 mm, which is greater than the critical insulation thickness. Therefore, the chances of condensation on the external surface of the duct could be avoided at an optimum insulation thickness. Moreover, the effect of pressure loss coefficient of the duct fitting of air distribution system is estimated. The electricity consumption in air handling unit (AHU) decreases from 2.1 to 1.5 kW by decreasing the pressure loss coefficient from 1.5 to 0.5.

Critical analysis of the condensation of water vapor at external surface of the duct

NASA Astrophysics Data System (ADS)

Kumar, Dileep; Memon, Rizwan Ahmed; Memon, Abdul Ghafoor; Ali, Intizar; Junejo, Awais

2018-07-01

In this paper, the effects of contraction of the insulation of the air duct of heating, ventilation, and air conditioning (HVAC) system is investigated. The compression of the insulation contracts it at joint, turn and other points of the duct. The energy loss and the condensation resulted from this contraction are also estimated. A mathematical model is developed to simulate the effects of this contraction on the heat gain, supply air temperature and external surface temperature of the duct. The simulation uses preliminary data obtained from an HVAC system installed in a pharmaceutical company while varying the operating conditions. The results reveal that insulation thickness should be kept greater than 30 mm and the volume flow rate of the selected air distribution system should be lower than 1.4m3/s to subside condensation on the external surface of the duct. Additionally, the optimum insulation thickness was determined by considering natural gas as an energy source and fiberglass as an insulation material. The optimum insulation thickness determined for different duct sizes varies from 28 to 45 mm, which is greater than the critical insulation thickness. Therefore, the chances of condensation on the external surface of the duct could be avoided at an optimum insulation thickness. Moreover, the effect of pressure loss coefficient of the duct fitting of air distribution system is estimated. The electricity consumption in air handling unit (AHU) decreases from 2.1 to 1.5 kW by decreasing the pressure loss coefficient from 1.5 to 0.5.

Treatment of poly(ethylene terephthalate) foils by atmospheric pressure air dielectric barrier discharge and its influence on cell growth

NASA Astrophysics Data System (ADS)

Kuzminova, Anna; Vandrovcová, Marta; Shelemin, Artem; Kylián, Ondřej; Choukourov, Andrei; Hanuš, Jan; Bačáková, Lucie; Slavínská, Danka; Biederman, Hynek

2015-12-01

In this contribution an effect of dielectric barrier discharge (DBD) sustained in air at atmospheric pressure on surface properties of poly(ethylene terephthalate) (PET) foils is studied. It is found that exposure of PET to DBD plasma leads to rapid changes of surface chemical composition, wettability, surface morphology as well as mechanical properties of PET surface. In addition, based on biological tests that were performed using two cell types (Saos-2 human osteoblast-like cells and HUVEC human umbilical vein endothelial cells), it may be concluded that DBD plasma treatment positively influences cell growth on PET. This effect was found to be connected predominantly with increased surface energy and oxygen content of the surface of treated PET foils.

Migration of Beryllium via Multiple Exposure Pathways among Work Processes in Four Different Facilities.

PubMed

Armstrong, Jenna L; Day, Gregory A; Park, Ji Young; Stefaniak, Aleksandr B; Stanton, Marcia L; Deubner, David C; Kent, Michael S; Schuler, Christine R; Virji, M Abbas

2014-01-01

Inhalation of beryllium is associated with the development of sensitization; however, dermal exposure may also be important. The primary aim of this study was to elucidate relationships among exposure pathways in four different manufacturing and finishing facilities. Secondary aims were to identify jobs with increased levels of beryllium in air, on skin, and on surfaces; identify potential discrepancies in exposure pathways, and determine if these are related to jobs with previously identified risk. Beryllium was measured in air, on cotton gloves, and on work surfaces. Summary statistics were calculated and correlations among all three measurement types were examined at the facility and job level. Exposure ranking strategies were used to identify jobs with higher exposures. The highest air, glove, and surface measurements were observed in beryllium metal production and beryllium oxide ceramics manufacturing jobs that involved hot processes and handling powders. Two finishing and distribution facilities that handle solid alloy products had lower exposures than the primary production facilities, and there were differences observed among jobs. For all facilities combined, strong correlations were found between air-surface (rp ≥ 0.77), glove-surface (rp ≥ 0.76), and air-glove measurements (rp ≥ 0.69). In jobs where higher risk of beryllium sensitization or disease has been reported, exposure levels for all three measurement types were higher than in jobs with lower risk, though they were not the highest. Some jobs with low air concentrations had higher levels of beryllium on glove and surface wipe samples, suggesting a need to further evaluate the causes of the discrepant levels. Although such correlations provide insight on where beryllium is located throughout the workplace, they cannot identify the direction of the pathways between air, surface, or skin. Ranking strategies helped to identify jobs with the highest combined air, glove, and/or surface exposures. All previously identified high-risk jobs had high air concentrations, dermal mass loading, or both, and none had low dermal and air. We have found that both pathways are relevant. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file describing the forms of beryllium materials encountered during production and characteristics of the aerosols by process areas.].

Dispersion relation of a surface wave at a rough metal-air interface

DOE PAGES

Kotelnikov, Igor; Stupakov, Gennady

2016-11-28

Here, we derived a dispersion relation of a surface wave at a rough metal-air interface. In contrast to previous publications, we assumed that an intrinsic surface impedance due to a finite electric conductivity of the metal can be of the same order as the roughness-induced impedance. We then applied our results to the analysis of a long-standing problem of the discrepancy between the experimental data on the propagation of surface waves in the terahertz range of frequencies and the classical Drude theory.

Comparative study on gamma irradiation and cold plasma pretreatment for a cellulosic substrate modification with phenolic compounds

NASA Astrophysics Data System (ADS)

Irimia, Anamaria; Ioanid, Ghiocel Emil; Zaharescu, Traian; Coroabă, Adina; Doroftei, Florica; Safrany, Agnes; Vasile, Cornelia

2017-01-01

The efficiency of the activation of the cellulose/chitin mix substrate by cold plasma or γ-radiation exposure in order to modify it with bioactive compounds was studied. The eugenol or vegetable oils such as grape seed oil and rosehip seed oil have been grafted onto activated substrate. The examination of modified cellulose/chitin mix substrate by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy confirms that the structural and morphological changes took place in both cases. The grafting degrees of the surface layer estimated from XPS data varied from 31.1% to 58.7% for air cold plasma activation and from 9.7% to 22.8% for γ-irradiation treatment. They depend both on bioactive compound used and procedure of substrate activation. Higher grafting degree are obtain by using vegetable oils than in the case of modification with eugenol and the air cold plasma activation seems to be much efficient than γ-irradiation. By grafting the polymeric substrate with bioactive compounds, antimicrobial and antioxidant properties have been conferred. Such materials can be considered promising for food packaging applications and medical textiles and also the applied procedures are environmental friendly ones.

Nanograin Ceramic Optical Composite Window

DTIC Science & Technology

2005-07-15

parts are sintered in air at 1100 C̊. Table 1: Carbon content of the calcined Alumina- Zirconia powders analyzed by LECO Calcination Temperature Carbon...estimated particle size of the Alumina and Zirconia powders Material name Surface area (m2/g) Estimated particle size (nm) Alumina 315.7 4.7 Zirconia...200 300 400 500 600 700 800 900 1000 2-Theta - Scale 20 30 40 50 60 70 80 Figure 3: XRD patterns of zirconia powder prepared by sonochemical method

Tropospheric HONO Distribution and Chemistry in the Southeastern U.S.

NASA Astrophysics Data System (ADS)

Zhou, X.; Ye, C.; Pu, D.; Stutz, J.; Festa, J.; Spolaor, M.; Weinheimer, A. J.; Campos, T. L.; Haggerty, J. A.; Cantrell, C. A.; Mauldin, L.; Guenther, A. B.; Hornbrook, R. S.; Apel, E. C.; Jensen, J. B.

2014-12-01

During the NOMADSS field campaign, nitrous acid (HONO) and particulate nitrate (pNO3) was measured on NCAR C-130 research aircraft during five research flights over the Southeast U.S. Aerosol samples were also collected on Teflon filters for the determination of pNO3 photolysis rate constants in the laboratory. Daytime HONO concentrations range from low ppt in free troposphere to 10-20 ppt in the boundary layer in the background air masses, to up to 40 ppt in the industrial and urban plumes. While daytime HONO sink is well defined, dominated by its photolysis, daytime sources vary in different types of air masses: pNO3 photolysis appears to be the major HONO source in the background terrestrial air masses in both the boundary layer and the free troposphere. With an average pNO3 photolysis rate constant of (2.8±1.7)×10-4 s-1, p-NO3 photolysis becomes to be an effective pathway to recycle HNO3 to NOx in the troposphere, with HONO as a dominant intermediate product. Within the high-NOx industrial plumes encountered, HONO is predominantly produced by secondary formation processes involving NOx as the precursor. Away from ground surface, no significant nighttime HONO accumulation exists in the background terrestrial air mass.

Hybrid radiator cooling system

DOEpatents

France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

2016-03-15

A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

30 CFR 7.84 - Technical requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Underground Coal Mines § 7.84 Technical requirements. (a) Fuel injection adjustment. The fuel injection system of the engine shall be constructed so that the quantity of fuel injected can be controlled at a... design. (b) Maximum fuel-air ratio. At the maximum fuel-air ratio determined by § 7.87 of this part, the...

30 CFR 7.84 - Technical requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Underground Coal Mines § 7.84 Technical requirements. (a) Fuel injection adjustment. The fuel injection system of the engine shall be constructed so that the quantity of fuel injected can be controlled at a... design. (b) Maximum fuel-air ratio. At the maximum fuel-air ratio determined by § 7.87 of this part, the...

30 CFR 7.84 - Technical requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Underground Coal Mines § 7.84 Technical requirements. (a) Fuel injection adjustment. The fuel injection system of the engine shall be constructed so that the quantity of fuel injected can be controlled at a... design. (b) Maximum fuel-air ratio. At the maximum fuel-air ratio determined by § 7.87 of this part, the...

30 CFR 7.84 - Technical requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Underground Coal Mines § 7.84 Technical requirements. (a) Fuel injection adjustment. The fuel injection system of the engine shall be constructed so that the quantity of fuel injected can be controlled at a... design. (b) Maximum fuel-air ratio. At the maximum fuel-air ratio determined by § 7.87 of this part, the...

30 CFR 7.84 - Technical requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Underground Coal Mines § 7.84 Technical requirements. (a) Fuel injection adjustment. The fuel injection system of the engine shall be constructed so that the quantity of fuel injected can be controlled at a... design. (b) Maximum fuel-air ratio. At the maximum fuel-air ratio determined by § 7.87 of this part, the...

Durability of resin cement bond to aluminium oxide and zirconia ceramics after air abrasion and laser treatment.

PubMed

Foxton, Richard M; Cavalcanti, Andrea N; Nakajima, Masatoshi; Pilecki, Peter; Sherriff, Martyn; Melo, Luciana; Watson, Timothy F

2011-02-01

The erbium laser has been introduced for cutting enamel and dentin and may have an application in the surface modification of high-strength aluminum oxide and zirconia ceramics. The aim of this study was to evaluate the durability of the bond of conventional dual-cured resin cements to Procera Al(2)O(3) and zirconium oxide ceramics after surface treatment with air abrasion and erbium laser. One hundred twenty Al(2)O(3) and 120 zirconia specimens measuring 3 × 3 × 0.7 mm(3) were divided equally into three groups, and their surfaces treated as follows: either untreated (controls), air abraded with Al(2)O(3) particles, or erbium-laser-treated at a power setting of 200 mJ. The surface of each specimen was then primed and bonded with one of two dual-cured resin cements (either SCP-100 Ceramic Primer and NAC-100 or Monobond S and Variolink II) using a 1-mm thick Tygon tube mold with a 0.75-mm internal bore diameter. After 24 hours and 6 months of water storage at 37°C, a microshear bond strength test was performed at a crosshead speed of 1 mm/min. Surface morphology was examined using a confocal microscope, and failure modes were observed using an optical microscope. The data were analyzed using the Kaplan-Meier nonparametric survival analysis. In the case of zirconia, air abrasion and Erbium:yttrium-aluminum-garnet (Er:YAG) laser treatment of the ceramic surface resulted in a significant reduction in the bond strengths of both resin cements after 6 months water storage; however, when the zirconia surface was left untreated, the SCP-100/NAC-100 group did not significantly reduce in bond strength. In the case of alumina, no treatment, air abrasion and Er:YAG laser treatment of the surface led to no significant reduction in the bond strengths of the three SCP-100/NAC-100 groups after 6 months water storage, whereas all three Monobond S/Variolink II groups showed a significant reduction. Er:YAG laser treatment of the zirconia surface did not result in a durable resin cement/ceramic bond; however, a durable bond between a conventional dual-cured resin cement and Procera All Ceram and Procera All Zirkon was formed using a ceramic primer containing the phosphate monomer, MDP, without any additional surface treatment. © 2011 by The American College of Prosthodontists.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, X; Wu, H; Rosen, L

Purpose: To treat superficial target e.g. chest wall, head&neck or cranial cases, we commissioned two range shifter(RS) in Raystation4.0 with 7.37cm(RS1) and 4.1cm(RS2) Water Equivalent Thickness(WET) respectively. However, current beam model has limitations due to the secondary scattered proton. This study provides a detailed and critical commission data and provides suggestions for using RS in clinic. Methods: RS’ WET was verified by Multi-Layer Ionization Chamber from 120MeV to 226.7MeV before TPS modeling. Spot characteristics were measured using 2D scintillate detector at ISO with different air gap. A 8×8×10cm3 cube is created in 8cm depth of water to verify the absolutemore » dose accuracy. Plans were created with different air gap using both RS. Absolute dose verification was measured along the central axis from distal end to surface using PPC05. 10 clinical RS2 plans were measured using MatriXXPT in 3 planes (proximal, distal and midSOBP). Results: RS material’s proton stopping power is energy dependent(from 70MeV to 226.7MeV) ranging from 7.42 to 7.31cm and from 4.10 to 4.03cm respectively. We chose 7.37cm (RS1) and 4.10cm (RS2) to favor the low and median proton energy. With different air gap(3cm to 32cm), spot size expands from 3.2mm to 5.5mm(RS1) and from 3.1mm to 4.1mm(RS2) respectively(226.7MeV in air, 1-sigma). For the absolute dose verification, the larger air gap and shallower depth causes larger discrepancy between TPS and measurements. All 10 clinical plans with 5–10cm air gap passed gamma index 95% with 3%/3mm criteria and outputs differences were within 3%. Conclusion: We strongly recommend each institution to verify the WET independently and choose the value to fit the clinical needs. To minimize the output difference in Raystation4.0 while avoid potential collision to the patient, we recommend to use 5–10cm air gap to minimize the output difference within 2% and preferably use RS with smaller WET if possible.« less

Equipment for Hot-to-serve Foods

NASA Technical Reports Server (NTRS)

Smith, D. P.

1985-01-01

Patented surface heating devices with a much faster air-to-solid heat transfer rate than previous air ovens were developed. The accelerated surface heating can brown, sear or crisp much more rapidly than in conventional ovens so that partially prepared food can be finished quickly and tastefully immediately before serving. The crisp, freshly browned surfaces result from the faster heat transfer which does not dry out the food. The devices are then compared to convection ovens and microwave heating processes.

The environmental deposition of influenza virus from patients infected with influenza A(H1N1)pdm09: Implications for infection prevention and control.

PubMed

Killingley, Benjamin; Greatorex, Jane; Digard, Paul; Wise, Helen; Garcia, Fayna; Varsani, Harsha; Cauchemez, Simon; Enstone, Joanne E; Hayward, Andrew; Curran, Martin D; Read, Robert C; Lim, Wei S; Nicholson, Karl G; Nguyen-Van-Tam, Jonathan S

2016-01-01

In a multi-center, prospective, observational study over two influenza seasons, we sought to quantify and correlate the amount of virus recovered from the nares of infected subjects with that recovered from their immediate environment in community and hospital settings. We recorded the symptoms of adults and children with A(H1N1)pdm09 infection, took nasal swabs, and sampled touched surfaces and room air. Forty-two infected subjects were followed up. The mean duration of virus shedding was 6.2 days by PCR (Polymerase Chain Reaction) and 4.2 days by culture. Surface swabs were collected from 39 settings; 16 (41%) subject locations were contaminated with virus. Overall, 33 of the 671 (4.9%) surface swabs were PCR positive for influenza, of which two (0.3%) yielded viable virus. On illness Day 3, subjects yielding positive surface samples had significantly higher nasal viral loads (geometric mean ratio 25.7; 95% CI 1.75, 376.0, p=0.021) and a positive correlation (r=0.47, p=0.006) was observed between subject nasal viral loads and viral loads recovered from the surfaces around them. Room air was sampled in the vicinity of 12 subjects, and PCR positive samples were obtained for five (42%) samples. Influenza virus shed by infected subjects did not detectably contaminate the vast majority of surfaces sampled. We question the relative importance of the indirect contact transmission of influenza via surfaces, though our data support the existence of super-spreaders via this route. The air sampling results add to the accumulating evidence that supports the potential for droplet nuclei (aerosol) transmission of influenza. Copyright © 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

[Effects of land use type on diurnal dynamics of environment microclimate in Karst zone].

PubMed

Li, Sheng; Ren, Hua-Dong; Yao, Xiao-Hua; Zhang, Shou-Gong

2009-02-01

In June 2007, the diurnal dynamics of light intensity, air temperature, air relative humidity, soil temperature, and surface soil (0-5 cm) water content of five land use types in the typical Karst zone of Lingyun City in Guangxi Zhuang Autonomous Region were observed. The results showed that different land use types altered the composition, coverage, and height of aboveground vegetation, which in turn changed the environment microclimate to different degree. The microclimate quality was in the order of forestland > shrub land > grassland > farmland > rock land. On rock land, the light intensity, air temperature, air relative humidity, soil temperature, and soil water content were higher, and the diurnal variation of the five climatic factors was notable, with the microclimatic conditions changed towards drier and hotter. Compared with those on rock land, the light intensity on forestland, shrub land, grassland, and farmland decreased by 96.4%, 52.0%, 17.0% and 44.2%, air temperature decreased by 30.1%, 20.2%, 12.7% and 17.8%, air relative humidity increased by 129.2%, 57.2%, 18.0% and 41.2%, soil temperature decreased by 11.5%, 8%, 2.5% and 5.5%, and soil water content increased by 42.6%, 33.2%, 15.7% and 14.0%, respectively. The five climatic factors on forestland and shrub land had lesser fluctuation, with the microclimate tended to cool and wet. Light intensity, air temperature, and soil temperature correlated positively with each other, and had negative correlations with air relative humidity and soil water content. A positive correlation was observed between air temperature and soil water content.

Activated boron nitride as an effective adsorbent for metal ions and organic pollutants

PubMed Central

Li, Jie; Xiao, Xing; Xu, Xuewen; Lin, Jing; Huang, Yang; Xue, Yanming; Jin, Peng; Zou, Jin; Tang, Chengchun

2013-01-01

Novel activated boron nitride (BN) as an effective adsorbent for pollutants in water and air has been reported in the present work. The activated BN was synthesized by a simple structure-directed method that enabled us to control the surface area, pore volume, crystal defects and surface groups. The obtained BN exhibits an super high surface area of 2078 m2/g, a large pore volume of 1.66 cm3/g and a special multimodal microporous/mesoporous structure located at ~ 1.3, ~ 2.7, and ~ 3.9 nm, respectively. More importantly, the novel activated BN exhibits an excellent adsorption performance for various metal ions (Cr3+, Co2+, Ni2+, Ce3+, Pb2+) and organic pollutants (tetracycline, methyl orange and congo red) in water, as well as volatile organic compounds (benzene) in air. The excellent reusability of the activated BN has also been confirmed. All the features render the activated BN a promising material suitable for environmental remediation. PMID:24220570

Expanding NevCAN capabilities: monitoring cold air drainage flow along a narrow wash within a Montane to PJ ecotone

NASA Astrophysics Data System (ADS)

Bird, B. M.; Devitt, D.

2012-12-01

Cold air drainage flows are a naturally occurring physical process of mountain systems. Plant communities that exist in cold air drainage basins respond to these localized cold air trends, and have been shown to be decoupled from larger global climate weather systems. The assumption that air temperature decreases with altitude is violated within these systems and climate model results based on this assumption would ultimately be inaccurate. In arid regions, high radiation loads lead to significant long wave radiation being emitted from the ground later in the day. As incoming radiation ceases, the surface very quickly loses energy through radiative processes, leading to surface inversions and enhanced cold air drainage opportunities. This study is being conducted in the Mojave desert on Sheep Mountain located between sites 3 and 4 of the NSF EPSCoR network. Monitoring of cold air drainage was initiated in September of 2011within a narrow ravine located between the 2164 and 2350 meter elevation. We have installed 25 towers (5 towers per location situated at the central low point in a ravine and at equal distances up the sides of the ravine on both the N and S facing slopes) to assess air temperatures from 0.1 meters to a height of 3 meters at 25m intervals. Our goal is to better understand the connection between cold air movement and plant physiological response. The species monitored in this study include: Pinus ponderosa (common name: Ponderosa Pine), Pinus pinyon (Pinyon Pine), Juniperus osteosperma (Utah juniper), Cercocarpus intricatus (Mountain Mahogany) and Symphoricarpos (snowberry). Hourly air temperature measurements within the wash are being captured from 100 ibuttons placed within PVC solar radiation shields. We are also developing a modeling approach to assess the three dimensional movement of cold air over time by incorporating wind vectors captured from 5 2D sonic anemometers. Wind velocities will be paired with air temperatures to better understand the thermal dynamics of cold air drainage. Granier probes were installed in the five test species to monitor transpirational flow relative to cold air movement. Mid day soil - plant - water measurements are also being taken on a monthly basis during the growing season at all locations. Measurements include: leaf xylem water potential, stomata conductance, chlorophyll index readings, canopy minus ambient temperatures and surface soil moisture contents. To date the monitoring system has revealed cold air drainage occurring during periods of every month. We will report the physiological response of the five plant species, with emphasis on assessing the linkages with cold air movement.

Oxidation Resistance of Materials Based on Ti3AlC2 Nanolaminate at 600 °C in Air.

PubMed

Ivasyshyn, Andrij; Ostash, Orest; Prikhna, Tatiana; Podhurska, Viktoriya; Basyuk, Tatiana

2016-12-01

The oxidation behavior of Ti3AlC2-based materials had been investigated at 600 °C in static air for 1000 h. It was shown that the intense increase of weight gain per unit surface area for sintered material with porosity of 22 % attributed to oxidation of the outer surface of the specimen and surfaces of pores in the bulk material. The oxidation kinetics of the hot-pressed Ti3AlC2-based material with 1 % porosity remarkably increased for the first 15 h and then slowly decreased. The weight gain per unit surface area for this material was 1.0 mg/cm(2) after exposition for 1000 h. The intense initial oxidation of Ti3AlC2-based materials can be eliminated by pre-oxidation treatment at 1200 °C in air for 2 h. As a result, the weight gain per unit surface area for the pre-oxidized material did not exceed 0.11 mg/cm(2) after 1000 h of exposition at 600 °C in air. It was demonstrated that the oxidation resistance of Ti3AlC2-based materials can be significantly improved by niobium addition.

Graphene Based Surface Plasmon Polariton Modulator Controlled by Ferroelectric Domains in Lithium Niobate

PubMed Central

Wang, Hao; Zhao, Hua; Hu, Guangwei; Li, Siren; Su, Hang; Zhang, Jingwen

2015-01-01

We proposed a ferroelectric domain controlled graphene based surface plasmon polariton modulator. Ferroelectricity-induced electronic and optical property tuning of graphene by domain in lithium niobate was theoretically investigated considering both interband and intraband contributions of surface conductivity. With the corrected Sellmeier equation of lithium niobate, the propagation of transverse magnetic mode surface plasmon polaritons in an air/graphene/lithium niobate structure was studied when monolayer graphene was tuned by down polarization direction ferroelectric domain with different polarization levels. The length of the ferroelectric domain was optimized to be 90 nm for a wavelength of 5.0 μm with signal extinction per unit 14.7 dB/μm, modulation depth 474.1 dB/μm and figure of merit 32.5. This work may promote the study of highly efficient modulators and other ultra-compact nonvolatile electronic and photonic devices in which two-dimensional materials and ferroelectric materials are combined. PMID:26657622

Perception of airborne odors by loggerhead sea turtles.

PubMed

Endres, C S; Putman, N F; Lohmann, K J

2009-12-01

Sea turtles are known to detect chemical cues, but in contrast to most marine animals, turtles surface to breathe and thus potentially have access to olfactory cues both in air and in water. To determine whether sea turtles can detect airborne chemical cues, captive loggerhead turtles (Caretta caretta) were placed into a circular, water-filled arena in which odorants could be introduced to the air above the water surface. Air that had passed across the surface of a cup containing food elicited increased activity, diving and other behavior normally associated with feeding. By contrast, air that had passed across the surface of an identical cup containing distilled water elicited no response. Increases in activity during food odor trials occurred only after turtles surfaced to breathe and peaked in the first post-breath minute, implying that the chemical cues eliciting the responses were unlikely to have been detected while the turtles were under water. These results provide the first direct evidence that sea turtles can detect airborne odors. Under natural conditions, this sensory ability might function in foraging, navigation or both.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

PubMed Central

Edmondson, J. L.; Stott, I.; Davies, Z. G.; Gaston, K. J.; Leake, J. R.

2016-01-01

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health. PMID:27641002

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.

PubMed

Edmondson, J L; Stott, I; Davies, Z G; Gaston, K J; Leake, J R

2016-09-19

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

NASA Astrophysics Data System (ADS)

Edmondson, J. L.; Stott, I.; Davies, Z. G.; Gaston, K. J.; Leake, J. R.

2016-09-01

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

The surface activity of purified ocular mucin at the air-liquid interface and interactions with meibomian lipids.

PubMed

Millar, Thomas J; Tragoulias, Sophia T; Anderton, Philip J; Ball, Malcolm S; Miano, Fausto; Dennis, Gary R; Mudgil, Poonam

2006-01-01

Ocular mucins are thought to contribute to the stability of the tear film by reducing surface tension. The purpose of this study was to compare the effect of different mucins and hyaluronic acid (HA) alone and mixed with meibomian lipids on the surface pressure at an air-liquid interface. A Langmuir trough and Wilhelmy balance were used to measure and compare the surface activity of bovine submaxillary gland mucin (BSM), purified BSM, purified bovine ocular mucin and HA, and mixtures of these with meibomian lipids, phosphatidylcholine, and phosphatidylglycerol. Their appearance at the surface of an air-buffer interface was examined using epifluorescence microscopy. Purified ocular mucin had no surface activity even at concentrations that were 100 times more than normally occur in tears. By contrast, commercial BSM caused changes to surface pressure that were concentration dependent. The surface pressure-area profiles showed surface activity with maximum surface pressures of 12.3-22.5 mN/m depending on the concentration. Purified BSM showed no surface activity at low concentrations, whereas higher concentrations reached a maximum surface pressure of 25 mN/m. HA showed no surface activity, at low or high concentrations. Epifluorescence showed that the mucins were located at the air-buffer interface and changed the appearance of lipid films. Purified bovine ocular mucin and HA have no surface activity. However, despite having no surface activity in their own right, ocular mucins are likely to be present at the surface of the tear film, where they cause an increase in surface pressure by causing a compression of the lipids (a reorganization of the lipids) and alter the viscoelastic properties at the surface.

Interaction between Air Bubbles and Superhydrophobic Surfaces in Aqueous Solutions.

PubMed

Shi, Chen; Cui, Xin; Zhang, Xurui; Tchoukov, Plamen; Liu, Qingxia; Encinas, Noemi; Paven, Maxime; Geyer, Florian; Vollmer, Doris; Xu, Zhenghe; Butt, Hans-Jürgen; Zeng, Hongbo

2015-07-07

Superhydrophobic surfaces are usually characterized by a high apparent contact angle of water drops in air. Here we analyze the inverse situation: Rather than focusing on water repellency in air, we measure the attractive interaction of air bubbles and superhydrophobic surfaces in water. Forces were measured between microbubbles with radii R of 40-90 μm attached to an atomic force microscope cantilever and submerged superhydrophobic surfaces. In addition, forces between macroscopic bubbles (R = 1.2 mm) at the end of capillaries and superhydrophobic surfaces were measured. As superhydrophobic surfaces we applied soot-templated surfaces, nanofilament surfaces, micropillar arrays with flat top faces, and decorated micropillars. Depending on the specific structure of the superhydrophobic surfaces and the presence and amount of entrapped air, different interactions were observed. Soot-templated surfaces in the Cassie state showed superaerophilic behavior: Once the electrostatic double-layer force and a hydrodynamic repulsion were overcome, bubbles jumped onto the surface and fully merged with the entrapped air. On nanofilaments and micropillar arrays we observed in addition the formation of sessile bubbles with finite contact angles below 90° or the attachment of bubbles, which retained their spherical shape.

Comparison between AVHRR surface temperature data and in-situ weather station temperatures over the Greenland Ice Sheet

NASA Astrophysics Data System (ADS)

Rezvanbehbahani, S.; Csatho, B. M.; Comiso, J. C.; Babonis, G. S.

2011-12-01

Advanced Very-High Resolution Radiometer (AVHRR) images have been exhaustively used to measure surface temperature time series of the Greenland Ice sheet. The purpose of this study is to assess the accuracy of monthly average ice sheet surface temperatures, derived from thermal infrared AVHRR satellite imagery on a 6.25 km grid. In-situ temperature data sets are from the Greenland Collection Network (GC-Net). GC-Net stations comprise sensors monitoring air temperature at 1 and 2 meter above the snow surface, gathered at every 60 seconds and monthly averaged to match the AVHRR temporal resolution. Our preliminary results confirm the good agreement between satellite and in-situ temperature measurements reported by previous studies. However, some large discrepancies still exist. While AVHRR provides ice surface temperature, in-situ stations measure air temperatures at different elevations above the snow surface. Since most in-situ data on ice sheets are collected by Automatic Weather Station (AWS) instruments, it is important to characterize the difference between surface and air temperatures. Therefore, we compared and analyzed average monthly AVHRR ice surface temperatures using data collected in 2002. Differences between these temperatures correlate with in-situ temperatures and GC-Net station elevations, with increasing differences at lower elevations and higher temperatures. The Summit Station (3199 m above sea level) and the Swiss Camp (1176 m above sea level) results were compared as high altitude and low altitude stations for 2002, respectively. Our results show that AVHRR derived temperatures were 0.5°K warmer than AWS temperature at the Summit Station, while this difference was 2.8°K in the opposite direction for the Swiss Camp with surface temperatures being lower than air temperatures. The positive bias of 0.5°K at the high altitude Summit Station (surface warmer than air) is within the retrieval error of AVHRR temperatures and might be in part due to atmospheric inversion. The large negative bias of 2.8°K at the low altitude Swiss Camp (surface colder than the air) could be caused by a combination of different factors including local effects such as more windy circumstances above the snow surface and biases introduced by the cloud-masking applied on the AVHRR images. Usually only satellite images acquired in clear-sky conditions are used for deriving monthly AVHRR average temperatures. Since cloud-free days are usually warmer, satellite derived temperatures tend to underestimate the real average temperatures, especially regions with frequent cloud cover, such as Swiss Camp. Therefore, cautions must be exercised while using ice surface temperatures derived from satellite imagery for glaciological applications. Eliminating the cloudy day's' temperature from the in-situ data prior to the comparison with AVHRR derived temperatures will provide a better assessment of AVHRR surface temperature measurement accuracy.

Amplification of the electroosmotic velocity by induced charges at fluidic interfaces

NASA Astrophysics Data System (ADS)

Steffes, Clarissa; Baier, Tobias; Hardt, Steffen

2010-11-01

The performance of microfluidic devices like electroosmotic pumps is strongly limited by drag forces at the channel walls. In order to replace the standard no-slip condition at the wall with a more favorable slip condition, superhydrophobic surfaces are employed. In the Cassie-Baxter state, air is entrapped in the surface cavities, so that a significant fraction of water-air interfaces at which slip does occur is provided. However, such surfaces do not enhance electroosmotic flow. Since no net charge accumulates at the water-air interfaces, the driving force is reduced, and no flow enhancement is obtained. We consider electrodes incorporated in the superhydrophobic structure to induce charges at these interfaces, thereby increasing the driving force. A theoretical model is set up, yielding an understanding of the influence of the surface morphology on the flow, which serves as a basis for ongoing experimental work. While a considerable enhancement of the electroosmotic velocity is already expected for standard superhydrophobic surfaces, greater amplifications of one order of magnitude may be achieved by substituting the air in the surface cavities by oil, reducing the risk for electric breakdown or transition to the unfavorable Wenzel state.

Global detailed gravimetric geoid. [based on gravity model derived from satellite tracking and surface gravity data

NASA Technical Reports Server (NTRS)

Vincent, S.; Marsh, J. G.

1973-01-01

A global detailed gravimetric geoid has been computed by combining the Goddard Space Flight Center GEM-4 gravity model derived from satellite and surface gravity data and surface 1 deg-by-1 deg mean free air gravity anomaly data. The accuracy of the geoid is + or - 2 meters on continents, 5 to 7 meters in areas where surface gravity data are sparse, and 10 to 15 meters in areas where no surface gravity data are available. Comparisons have been made with the astrogeodetic data provided by Rice (United States), Bomford (Europe), and Mather (Australia). Comparisons have also been carried out with geoid heights derived from satellite solutions for geocentric station coordinates in North America, the Caribbean, Europe, and Australia.

Versatile optical coherence tomography for imaging the human eye

PubMed Central

Tao, Aizhu; Shao, Yilei; Zhong, Jianguang; Jiang, Hong; Shen, Meixiao; Wang, Jianhua

2013-01-01

We demonstrated the feasibility of a CMOS-based spectral domain OCT (SD-OCT) for versatile ophthalmic applications of imaging the corneal epithelium, limbus, ocular surface, contact lens, crystalline lens, retina, and full eye in vivo. The system was based on a single spectrometer and an alternating reference arm with four mirrors. A galvanometer scanner was used to switch the reference beam among the four mirrors, depending on the imaging application. An axial resolution of 7.7 μm in air, a scan depth of up to 37.7 mm in air, and a scan speed of up to 70,000 A-lines per second were achieved. The approach has the capability to provide high-resolution imaging of the corneal epithelium, contact lens, ocular surface, and tear meniscus. Using two reference mirrors, the zero delay lines were alternatively placed on the front cornea or on the back lens. The entire ocular anterior segment was imaged by registering and overlapping the two images. The full eye through the pupil was measured when the reference arm was switched among the four reference mirrors. After mounting a 60 D lens in the sample arm, this SD-OCT was used to image the retina, including the macula and optical nerve head. This system demonstrates versatility and simplicity for multi-purpose ophthalmic applications. PMID:23847729

Extraction of CO2 from air samples for isotopic analysis and limits to ultra high precision delta18O determination in CO2 gas.

PubMed

Werner, R A; Rothe, M; Brand, W A

2001-01-01

The determination of delta18O values in CO2 at a precision level of +/-0.02 per thousand (delta-notation) has always been a challenging, if not impossible, analytical task. Here, we demonstrate that beyond the usually assumed major cause of uncertainty - water contamination - there are other, hitherto underestimated sources of contamination and processes which can alter the oxygen isotope composition of CO2. Active surfaces in the preparation line with which CO2 comes into contact, as well as traces of air in the sample, can alter the apparent delta18O value both temporarily and permanently. We investigated the effects of different surface materials including electropolished stainless steel, Duran glass, gold and quartz, the latter both untreated and silanized. CO2 frozen with liquid nitrogen showed a transient alteration of the 18O/16O ratio on all surfaces tested. The time to recover from the alteration as well as the size of the alteration varied with surface type. Quartz that had been ultrasonically cleaned for several hours with high purity water (0.05 microS) exhibited the smallest effect on the measured oxygen isotopic composition of CO2 before and after freezing. However, quartz proved to be mechanically unstable with time when subjected to repeated large temperature changes during operation. After several days of operation the gas released from the freezing step contained progressively increasing trace amounts of O2 probably originating from inclusions within the quartz, which precludes the use of quartz for cryogenically trapping CO2. Stainless steel or gold proved to be suitable materials after proper pre-treatment. To ensure a high trapping efficiency of CO2 from a flow of gas, a cold trap design was chosen comprising a thin wall 1/4" outer tube and a 1/8" inner tube, made respectively from electropolished stainless steel and gold. Due to a considerable 18O specific isotope effect during the release of CO2 from the cold surface, the thawing time had to be as long as 20 min for high precision delta18O measurements. The presence of traces of air in almost all CO2 gases that we analyzed was another major source of error. Nitrogen and oxygen in the ion source of our mass spectrometer (MAT 252, Finnigan MAT, Bremen, Germany) give rise to the production of NO2 at the hot tungsten filament. NO2+ is isobaric with C16O18O+ (m/z 46) and interferes with the delta18O measurement. Trace amounts of air are present in CO2 extracted cryogenically from air at -196 degrees C. This air, trapped at the cold surface, cannot be pumped away quantitatively. The amount of air present depends on the surface structure and, hence, the alteration of the measured delta18O value varies with the surface conditions. For automated high precision measurement of the isotopic composition of CO2 of air samples stored in glass flasks an extraction interface ('BGC-AirTrap') was developed which allows 18 analyses (including standards) per day to be made. For our reference CO2-in-air, stored in high pressure cylinders, the long term (>9 months) single sample precision was 0.012 per thousand for delta13C and 0.019 per thousand for delta18O. Copyright 2001 John Wiley & Sons, Ltd.

Properties of small-scale interfacial turbulence from a novel thermography based approach

NASA Astrophysics Data System (ADS)

Schnieders, Jana; Garbe, Christoph

2013-04-01

Oceans cover nearly two thirds of the earth's surface and exchange processes between the Atmosphere and the Ocean are of fundamental environmental importance. At the air-sea interface, complex interaction processes take place on a multitude of scales. Turbulence plays a key role in the coupling of momentum, heat and mass transfer [2]. Here we use high resolution infrared imagery to visualize near surface aqueous turbulence. Thermographic data is analized from a range of laboratory facilities and experimental conditions with wind speeds ranging from 1ms-1 to 7ms-1 and various surface conditions. The surface heat pattern is formed by distinct structures on two scales - small-scale short lived structures termed fish scales and larger scale cold streaks that are consistent with the footprints of Langmuir Circulations. There are two key characteristics of the observed surface heat patterns: (1) The surface heat patterns show characteristic features of scales. (2) The structure of these patterns change with increasing wind stress and surface conditions. We present a new image processing based approach to the analysis of the spacing of cold streaks based on a machine learning approach [4, 1] to classify the thermal footprints of near surface turbulence. Our random forest classifier is based on classical features in image processing such as gray value gradients and edge detecting features. The result is a pixel-wise classification of the surface heat pattern with a subsequent analysis of the streak spacing. This approach has been presented in [3] and can be applied to a wide range of experimental data. In spite of entirely different boundary conditions, the spacing of turbulent cells near the air-water interface seems to match the expected turbulent cell size for flow near a no-slip wall. The analysis of the spacing of cold streaks shows consistent behavior in a range of laboratory facilities when expressed as a function of water sided friction velocity, u*. The scales systematically decrease until a point of saturation at u* = 0.7 cm/s. Results suggest a saturation in the tangential stress, anticipating that similar behavior will be observed in the open ocean. A comparison with studies of small-scale Langmuir circulations and Langmuir numbers shows that thermal footprints in infrared images are consistent with Langmuir circulations and depend strongly on wind wave conditions. Our approach is not limited to laboratory measurments. In the near future, we will deploy it on in-situ measurements and verify our findings in these more challenging conditions. References [1] L. Breimann. Random forests. Machine Learning, 45:5-32, 2001. [2] S. P. McKenna and W. R. McGillis. The role of free-surface turbulence and surfactants in air-water gas transfer. Int. J. Heat Mass Transfer, 47:539-553, 2004. [3] J Schnieders, C. S. Garbe, W.L. Peirson, and C. J. Zappa. Analyzing the footprints of near surface aqueous turbulence - an image processing based approach. Journal of Geophysical Research-Oceans, 2013. [4] Christoph Sommer, Christoph Straehle, Ullrich Koethe, and Fred A. Hamprecht. ilastik: Interactive learning and segmentation toolkit. In 8th IEEE International Symposium on Biomedical Imaging (ISBI 2011), 2011. [5] W.-T. Tsai, S.-M. Chen, and C.-H. Moeng. A numerical study on the evolution and structure of a stress-driven free-surface turbulent shear flow. J. Fluid Mech., 545:163-192, 2005.

Indirect evaporative coolers with enhanced heat transfer

DOEpatents

Kozubal, Eric; Woods, Jason; Judkoff, Ron

2015-09-22

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