Coupling surface water (Delft3D) to groundwater (MODFLOW) in the Bay-Delta community model: the effect of major abstractions in the Delta

NASA Astrophysics Data System (ADS)

Hendriks, D.; Ball, S. M.; Van der Wegen, M.; Verkaik, J.; van Dam, A.

2016-12-01

We present a coupled groundwater-surface water model for the San Francisco Bay and Sacramento Valley that consists of a combination of a spatially-distributed groundwater model (Modflow) based on the USGS Central Valley model(1) and the Flexible Mesh (FM) surface water model of the Bay Area(2). With this coupled groundwater-surface water model, we assessed effects of climate, surface water abstractions and groundwater pumping on surface water and groundwater levels, groundwater-surface water interaction and infiltration/seepage fluxes. Results show that the effect of climate (high flow and low flow) on surface water and groundwater is significant and most prominent in upstream areas. The surface water abstractions cause significant local surface water levels decrease (over 2 m), which may cause inflow of bay water during low flow periods, resulting in salinization of surface water in more upstream areas. Groundwater level drawdown due to surface water withdrawal is moderate and limited to the area of the withdrawals. The groundwater pumping causes large groundwater level drawdowns (up to 0.8 m) and significant changes in seepage/infiltration fluxes in the model. However, the effect on groundwater-surface water exchange is relatively small. The presented model instrument gives a sound first impression of the effects of climate and water abstraction on both surface water and groundwater. The combination of Modflow and Flexible Mesh has potential for modelling of groundwater-surface water exchange in deltaic areas, also in other parts of the world. However, various improvements need to be made in order to make the simulation results useful in practice. In addition, a water quality aspect could be added to assess salinization processes as well as groundwater-surface water aspects of water and soil pollution. (1) http://ca.water.usgs.gov/projects/central-valley/central-valley-hydrologic-model.html (2) www.d3d-baydelta.org

Effect of solution and leaf surface polarity on droplet spread area and contact angle.

PubMed

Nairn, Justin J; Forster, W Alison; van Leeuwen, Rebecca M

2016-03-01

How much an agrochemical spray droplet spreads on a leaf surface can significantly influence efficacy. This study investigates the effect solution polarity has on droplet spreading on leaf surfaces and whether the relative leaf surface polarity, as quantified using the wetting tension dielectric (WTD) technique, influences the final spread area. Contact angles and spread areas were measured using four probe solutions on 17 species. Probe solution polarity was found to affect the measured spread area and the contact angle of the droplets on non-hairy leaves. Leaf hairs skewed the spread area measurement, preventing investigation of the influence of surface polarity on hairy leaves. WTD-measured leaf surface polarity of non-hairy leaves was found to correlate strongly with the effect of solution polarity on spread area. For non-polar leaf surfaces the spread area decreases with increasing solution polarity, for neutral surfaces polarity has no effect on spread area and for polar leaf surfaces the spread area increases with increasing solution polarity. These results attest to the use of the WTD technique as a means to quantify leaf surface polarity. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Comparison of Exposure in the Kaplan Versus the Kocher Approach in the Treatment of Radial Head Fractures.

PubMed

Barnes, Leslie Fink; Lombardi, Joseph; Gardner, Thomas R; Strauch, Robert J; Rosenwasser, Melvin P

2018-01-01

The aim of this study was to compare the complete visible surface area of the radial head, neck, and coronoid in the Kaplan and Kocher approaches to the lateral elbow. The hypothesis was that the Kaplan approach would afford greater visibility due to the differential anatomy of the intermuscular planes. Ten cadavers were dissected with the Kaplan and Kocher approaches, and the visible surface area was measured in situ using a 3-dimensional digitizer. Six measurements were taken for each approach by 2 surgeons, and the mean of these measurements were analyzed. The mean surface area visible with the lateral collateral ligament (LCL) preserved in the Kaplan approach was 616.6 mm 2 in comparison with the surface area of 136.2 mm 2 visible in the Kocher approach when the LCL was preserved. Using a 2-way analysis of variance, the difference between these 2 approaches was statistically significant. When the LCL complex was incised in the Kocher approach, the average visible surface area of the Kocher approach was 456.1 mm 2 and was statistically less than the Kaplan approach. The average surface area of the coronoid visible using a proximally extended Kaplan approach was 197.8 mm 2 . The Kaplan approach affords significantly greater visible surface area of the proximal radius than the Kocher approach.

Surface changes of poly-L-lactic acid due to annealing

NASA Astrophysics Data System (ADS)

Juřík, P.; Michaljaničová, I.; Slepička, P.; Kolskáa, Z.; Švorčík, V.

2017-11-01

Surface modifications are very important part of both current cutting-edge research and modern manufacturing. Our research is focused on poly-L-lactic acid, which is biocompatible and biodegradable polymer that offers applications in modern medicine. We observed morphological changes of the surface of metalized samples due to annealing and studied effect of modifications on total surface area and pore surface and volume. We observed that annealing of non-metalized samples had most pronounced effect up to the 70°C, after which all observed parameters dropped significantly. Metallization has changed behaviour of the samples significantly and resulted in generally lower surface area and porosity when compared to non-metalized samples.

Area densitometry using rotating Scheimpflug photography for posterior capsule opacification and surface light scattering analyses.

PubMed

Minami, Keiichiro; Honbo, Masato; Mori, Yosai; Kataoka, Yasushi; Miyata, Kazunori

2015-11-01

To compare area densitometry analysis using rotating Scheimpflug photography in quantifications of posterior capsule opacification (PCO) and surface light scattering with previous anterior-segment analyzer measurement. Miyata Eye Hospital, Miyazaki, Japan. Prospective observational case series. Scheimpflug images of eyes with foldable intraocular lenses (IOLs) were obtained using rotating and fixed Scheimpflug photography. Area densitometry on the posterior and anterior surfaces was conducted for PCO and surface light scattering analyses, respectively, with an identical area size. Correlation between two measurements was analyzed using linear regression. The study included 105 eyes of 74 patients who received IOLs 1 to 18 years (mean, 4.9 ± 4.5 years) postoperatively. In the PCO analysis on the posterior IOL surface, there was a significant correlation between the two measurements (P < .001, R(2) = 0.60). In the surface light scattering analysis, a significant and higher correlation was obtained (P < .001, R(2) = 0.91) until the fixed Scheimpflug photography exhibited saturation due to intensive scatterings. Area densitometry combined with a rotating Scheimpflug photography was exchangeable to previously established densitometry measurement, and allowed successive evaluation in longer-term observations. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Characterization of three commercial Y-TZP ceramics produced for their high-translucency, high-strength and high-surface area.

PubMed

Tong, Hui; Tanaka, Carina B; Kaizer, Marina R; Zhang, Yu

2016-01-01

Developing yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) with high strength and translucency could significantly widen the clinical indications of monolithic zirconia restorations. This study investigates the mechanical and optical properties of three Y-TZP ceramics: High-Translucency, High-Strength and High-Surface Area. The four-point bending strengths (mean ± standard error) for the three Y-TZP ceramics ( n = 10) were 990 ± 39, 1416 ± 33 and 1076 ± 32 MPa for High-Translucency, High-Strength and High-Surface Area, respectively. The fracture toughness values (mean ± standard error) for the three zirconias ( n = 10) were 3.24 ± 0.10, 3.63 ± 0.12 and 3.21 ± 0.14 MPa m 1/2 for High-Translucency, High-Strength and High-Surface Area, respectively. Both strength and toughness values of High-Strength zirconia were significantly higher than High-Surface Area and High-Translucency zirconias. Translucency parameter values of High-Translucency zirconia were considerably higher than High-Strength and High-Surface Area zirconias. However, all three zirconias became essentially opaque when their thickness reached 1 mm or greater. Our findings suggest that there exists a delicate balance between mechanical and optical properties of the current commercial Y-TZP ceramics.

Chronic cardiovascular disease mortality in mountaintop mining areas of central Appalachian states.

PubMed

Esch, Laura; Hendryx, Michael

2011-01-01

To determine if chronic cardiovascular disease (CVD) mortality rates are higher among residents of mountaintop mining (MTM) areas compared to mining and nonmining areas, and to examine the association between greater levels of MTM surface mining and CVD mortality. Age-adjusted chronic CVD mortality rates from 1999 to 2006 for counties in 4 Appalachian states where MTM occurs (N = 404) were linked with county coal mining data. Three groups of counties were compared: MTM, coal mining but not MTM, and nonmining. Covariates included smoking rate, rural-urban status, percent male population, primary care physician supply, obesity rate, diabetes rate, poverty rate, race/ethnicity rates, high school and college education rates, and Appalachian county. Linear regression analyses examined the association of mortality rates with mining in MTM areas and non-MTM areas and the association of mortality with quantity of surface coal mined in MTM areas. Prior to covariate adjustment, chronic CVD mortality rates were significantly higher in both mining areas compared to nonmining areas and significantly highest in MTM areas. After adjustment, mortality rates in MTM areas remained significantly higher and increased as a function of greater levels of surface mining. Higher obesity and poverty rates and lower college education rates also significantly predicted CVD mortality overall and in rural counties. MTM activity is significantly associated with elevated chronic CVD mortality rates. Future research is necessary to examine the socioeconomic and environmental impacts of MTM on health to reduce health disparities in rural coal mining areas. © 2011 National Rural Health Association.

Adolescent Body Size and Flexibility

ERIC Educational Resources Information Center

Krahenbuhl, Gary S.; Martin, Stephen L.

1977-01-01

Research suggests that differences in body surface area that occur during adolescence are significantly negatively related to knee, hip, and shoulder flexion-extension range, with flexibility decreasing as body surface area increases, with the relationship strongest for the knee. (MJB)

Effect of Reduced Phosphoric Acid Pre-etching Times 
on Enamel Surface Characteristics and Shear Fatigue Strength Using Universal Adhesives.

PubMed

Tsujimoto, Akimasa; Fischer, Nicholas; Barkmeier, Wayne; Baruth, Andrew; Takamizawa, Toshiki; Latta, Mark; Miyazaki, Masashi

2017-01-01

To examine the effect of reduced phosphoric acid pre-etching times on enamel fatigue bond strength of universal adhesives and surface characteristics by using atomic force microscopy (AFM). Three universal adhesives were used in this study (Clearfil Universal Bond [C], G-Premio Bond [GP], Scotchbond Universal Adhesive [SU]). Four pre-etching groups were employed: enamel pre-etched with phosphoric acid and immediately rinsed with an air-water spray, and enamel pre-etched with phosphoric acid for 5, 10, or 15 s. Ground enamel was used as the control group. For the initial bond strength test, 15 specimens per etching group for each adhesive were used. For the shear fatigue test, 20 specimens per etching group for each adhesive were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred. Initial shear bond strengths and fatigue shear strengths of composite adhesively bonded to ground and pre-etched enamel were determined. AFM observations of ground and pre-etched enamel were also conducted, and surface roughness as well as surface area were evaluated. The initial shear bond strengths and fatigue shear strengths of the universal adhesives in the pre-etched groups were significantly higher than those of the control group, and were not influenced by the pre-etching time. Significantly higher surface roughness and surface area of enamel surfaces in pre-etched groups were observed compared with those in the control group. While the surface area was not significantly influenced by etching time, surface roughness of the enamel surfaces in the pre-etched groups significantly increased with pre-etching time. The results of this in vitro study suggest that reduced phosphoric acid pre-etching times do not impair the fatigue bond strength of universal adhesives. Although fatigue bond strength and surface area were not influenced by phosphoric-acid etching times, surface roughness increased with increasing etching time.

Comparative Study of the Electrochemical, Biomedical, and Thermal Properties of Natural and Synthetic Nanomaterials

NASA Astrophysics Data System (ADS)

Ghaemi, Ferial; Abdullah, Luqman Chuah; Kargarzadeh, Hanieh; Abdi, Mahnaz M.; Azli, Nur Farhana Waheeda Mohd; Abbasian, Maryam

2018-04-01

In this research, natural nanomaterials including cellulose nanocrystal (CNC), nanofiber cellulose (NFC), and synthetic nanoparticles such as carbon nanofiber (CNF) and carbon nanotube (CNT) with different structures, sizes, and surface areas were produced and analyzed. The most significant contribution of this study is to evaluate and compare these nanomaterials based on the effects of their structures and morphologies on their electrochemical, biomedical, and thermal properties. Based on the obtained results, the natural nanomaterials with low dimension and surface area have zero cytotoxicity effects on the living cells at 12.5 and 3.125 μg/ml concentrations of NFC and CNC, respectively. Meanwhile, synthetic nanomaterials with the high surface area around 15.3-21.1 m2/g and significant thermal stability (480 °C-600 °C) enhance the output of electrode by creating a higher surface area and decreasing the current flow resistance.

City landscape changes effects on land surface temperature in Bucharest metropolitan area

NASA Astrophysics Data System (ADS)

Savastru, Dan M.; Zoran, Maria A.; Savastru, Roxana S.; Dida, Adrian I.

2017-10-01

This study investigated the influences of city land cover changes and extreme climate events on land surface temperature in relationship with several biophysical variables in Bucharest metropolitan area of Romania through satellite and in-situ monitoring data. Remote sensing data from IKONOS, Landsat TM/ETM+ and time series MODIS Terra/Aqua and NOAA AVHRR sensors have been used to assess urban land cover- temperature interactions over 2000 - 2016 period. Time series Thermal InfraRed (TIR) satellite remote sensing data in synergy with meteorological data (air temperatureAT, precipitations, wind, solar radiation, etc.) were applied mainly for analyzing land surface temperature (LST) pattern and its relationship with surface landscape characteristics, assessing urban heat island (UHI), and relating urban land cover temperatures (LST). The land surface temperature, a key parameter for urban thermal characteristics analysis, was also analyzed in relation with the Normalized Difference Vegetation Index (NDVI) at city level. Results show that in the metropolitan area ratio of impervious surface in Bucharest increased significantly during investigated period, the intensity of urban heat island and heat wave events being most significant. The correlation analyses revealed that, at the pixel-scale, LST and AT possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at metropolitan scale respectively. The NDVI was significantly correlated with precipitation. The spatial average air temperatures in urban test areas rise with the expansion of the urban size.

Relationship among land surface temperature and LUCC, NDVI in typical karst area.

PubMed

Deng, Yuanhong; Wang, Shijie; Bai, Xiaoyong; Tian, Yichao; Wu, Luhua; Xiao, Jianyong; Chen, Fei; Qian, Qinghuan

2018-01-12

Land surface temperature (LST) can reflect the land surface water-heat exchange process comprehensively, which is considerably significant to the study of environmental change. However, research about LST in karst mountain areas with complex topography is scarce. Therefore, we retrieved the LST in a karst mountain area from Landsat 8 data and explored its relationships with LUCC and NDVI. The results showed that LST of the study area was noticeably affected by altitude and underlying surface type. In summer, abnormal high-temperature zones were observed in the study area, perhaps due to karst rocky desertification. LSTs among different land use types significantly differed with the highest in construction land and the lowest in woodland. The spatial distributions of NDVI and LST exhibited opposite patterns. Under the spatial combination of different land use types, the LST-NDVI feature space showed an obtuse-angled triangle shape and showed a negative linear correlation after removing water body data. In summary, the LST can be retrieved well by the atmospheric correction model from Landsat 8 data. Moreover, the LST of the karst mountain area is controlled by altitude, underlying surface type and aspect. This study provides a reference for land use planning, ecological environment restoration in karst areas.

On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

DOE PAGES

Kovilakam, Mahesh; Deshler, Terry

2015-08-26

In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997-2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPCmore » measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15-30% (30-50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. Furthermore, this disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the ± 40% precision of the OPC moment calculations.« less

On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

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

Kovilakam, Mahesh; Deshler, Terry

In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991-1996) and nonvolcanic (1997-2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPCmore » measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15-30% (30-50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. Furthermore, this disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the ± 40% precision of the OPC moment calculations.« less

Effect of finishing instrumentation using NiTi hand files on volume, surface area and uninstrumented surfaces in C-shaped root canal systems.

PubMed

Amoroso-Silva, P; Alcalde, M P; Hungaro Duarte, M A; De-Deus, G; Ordinola-Zapata, R; Freire, L G; Cavenago, B C; De Moraes, I G

2017-06-01

To assess the effect of 90°-oscillatory instrumentation with hand files on several morphological parameters (volume, surface area and uninstrumented surface) in C-shaped root canals after instrumentation using a single-file reciprocation system (Reciproc; VDW, Munich, Germany) and a Self-Adjusting File System (SAF; ReDent Nova, Ra'anana, Israel). Twenty mandibular second molars with C-shaped canals and C1 canal configurations were divided into two groups (n = 10) and instrumented with Reciproc and SAF instruments. A size 30 NiTi hand K-file attached to a 90°-oscillatory motion handpiece was used as final instrumentation in both groups. The specimens were scanned using micro-computed tomography after all procedures. Volume, surface area increase and uninstrumented root canal surface were analysed using CTAn software (Bruker-microCT, Kontich, Belgium). Also, the uninstrumented root canal surface was calculated for each canal third. All values were compared between groups using the Mann-Whitney test and within groups using the Wilcoxon's signed-rank test. Instrumentation with Reciproc significantly increased canal volume compared with instrumentation with SAF. Additionally, the canal volumes were significantly increased after 90°-oscillatory instrumentation (between and within group comparison; (P < 0.05)). Regarding the increase in surface area after all instrumentation protocols, statistical analysis only revealed significant differences in the within groups comparison (P < 0.05). Reciproc and SAF instrumentation yielded an uninstrumented root canal surface of 28% and 34%, respectively, which was not significantly different (P > 0.05). Final oscillatory instrumentation significantly reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% (SAF; P < 0.05). The apical and middle thirds exhibited larger uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation (P < 0.05). The Reciproc and SAF system were associated with similar morphological parameters after instrumentation of mandibular second molars with C-shaped canals except for a higher canal volume increase in the Reciproc group compared to the SAF. Furthermore, the final use of 90°-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

The spatial-temporal dynamics of open surface water bodies in CONUS during 1984-2016

NASA Astrophysics Data System (ADS)

Zou, Z.; Xiao, X.; Dong, J.; Qin, Y.; Doughty, R.; Menarguez, M.; Wang, J.

2017-12-01

Open surface water bodies provided 80% of the total water withdrawals in the Contiguous United States (CONUS) in 1985-2010. The inter-annual variability and changing trends of surface water body areas have various impacts on the human society and ecosystems. This study made use of all Landsat 5, 7, and 8 surface reflectance archives ( 370,000 images) during 1984-2016 and a water index- and pixel-based approach to detect and map open surface water bodies in the cloud-based platform of Google Earth Engine. The year-long water body area and annual average water body area were calculated for each of the last 33 years and their inter-annual variations during 1984-2016 were analyzed through anomaly analysis while their changing trends were analyzed through linear regressions. The national annual average water body areas varied from 265,000 to 281,000 km2 during 1984-2016, which is 3% below to 3% above the mean value 274,000 km2. In state level, significant decreasing trends were found in both year-long and annual average water body areas in some states of dry climates in west and southwest U.S., including Oregon, Nevada, Utah, Arizona, New Mexico, and Oklahoma. In comparison, significant increasing trends were found in some states of wet climates in the southeast and north U.S., including Indiana, Ohio, New Jersey, Delaware, Virginia, Tennessee, North Carolina, South Carolina, Louisiana, Alabama, Georgia, North Dakota and South Dakota. Open surface water body areas in CONUS decreased in relatively dry areas but increased in relatively wet areas. The relationships between open surface water body area variability and climate factors (precipitation, temperature) and human impacts (water exploitation) were also analyzed.

Measuring the specific surface area of natural and manmade glasses: effects of formation process, morphology, and particle size

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

Papelis, Charalambos; Um, Wooyong; Russel, Charles E.

2003-03-28

The specific surface area of natural and manmade solid materials is a key parameter controlling important interfacial processes in natural environments and engineered systems, including dissolution reactions and sorption processes at solid-fluid interfaces. To improve our ability to quantify the release of trace elements trapped in natural glasses, the release of hazardous compounds trapped in manmade glasses, or the release of radionuclides from nuclear melt glass, we measured the specific surface area of natural and manmade glasses as a function of particle size, morphology, and composition. Volcanic ash, volcanic tuff, tektites, obsidian glass, and in situ vitrified rock were analyzed.more » Specific surface area estimates were obtained using krypton as gas adsorbent and the BET model. The range of surface areas measured exceeded three orders of magnitude. A tektite sample had the highest surface area (1.65 m2/g), while one of the samples of in situ vitrified rock had the lowest surf ace area (0.0016 m2/g). The specific surface area of the samples was a function of particle size, decreasing with increasing particle size. Different types of materials, however, showed variable dependence on particle size, and could be assigned to one of three distinct groups: (1) samples with low surface area dependence on particle size and surface areas approximately two orders of magnitude higher than the surface area of smooth spheres of equivalent size. The specific surface area of these materials was attributed mostly to internal porosity and surface roughness. (2) samples that showed a trend of decreasing surface area dependence on particle size as the particle size increased. The minimum specific surface area of these materials was between 0.1 and 0.01 m2/g and was also attributed to internal porosity and surface roughness. (3) samples whose surface area showed a monotonic decrease with increasing particle size, never reaching an ultimate surface area limit within the particle size range examined. The surface area results were consistent with particle morphology, examined by scanning electron microscopy, and have significant implications for the release of radionuclides and toxic metals in the environment.« less

Analysis of the sorption properties of different soils using water vapour adsorption and potentiometric titration methods

NASA Astrophysics Data System (ADS)

Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

2016-07-01

Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g-1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=-0.736; α = 0.05) as well as ash content (R=-0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g-1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.

Morphological abnormalities in prefrontal surface area and thalamic volume in attention deficit/hyperactivity disorder.

PubMed

Batty, Martin J; Palaniyappan, Lena; Scerif, Gaia; Groom, Madeleine J; Liddle, Elizabeth B; Liddle, Peter F; Hollis, Chris

2015-08-30

Although previous morphological studies have demonstrated abnormalities in prefrontal cortical thickness in children with attention deficit/hyperactivity disorder (ADHD), studies investigating cortical surface area are lacking. As the development of cortical surface is closely linked to the establishment of thalam-ocortical connections, any abnormalities in the structure of the thalamus are likely to relate to altered cortical surface area. Using a clinically well-defined sample of children with ADHD (n = 25, 1 female) and typically developing controls (n = 24, 1 female), we studied surface area across the cortex to determine whether children with ADHD had reduced thalamic volume that related to prefrontal cortical surface area. Relative to controls, children with ADHD had a significant reduction in thalamic volume and dorsolateral prefrontal cortical area in both hemispheres. Furthermore, children with ADHD with smaller thalamic volumes were found to have greater reductions in surface area, a pattern not evident in the control children. Our results are further evidence of reduced lateral prefrontal cortical area in ADHD. Moreover, for the first time, we have also shown a direct association between thalamic anatomy and frontal anatomy in ADHD, suggesting the pathophysiological process that alters surface area maturation is likely to be linked to the development of the thalamus. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Long-term studies on the effects of nonvolatile organic compounds on porous media surface areas.

PubMed

Khachikian, Crist S; Harmon, Thomas C

2002-01-01

This paper investigates the long-term behavior of porous media contaminated by nonvolatile organic compounds (NVOC) in terms of specific interfacial surface area. Specifically, a natural sand, Moffett sand (MS), was contaminated with naphthalene and the surface area was measured repeatedly over time using nitrogen adsorption-desorption techniques. A field-contaminated sand affected by lamp-black material (LB) from former manufactured gas plant operations was also studied. Lampblack is a carbonaceous skeleton containing polycyclic aromatic hydrocarbons (PAHs) and other hydrocarbons. It is hypothesized that soils contaminated by these types of chemicals will exhibit significantly less surface area than their clean counterparts. The surface areas for the contaminated MS samples increased toward their clean-MS values during the 700-h aging period, but achieved the clean values only after pentane extraction or heating at 60 degrees C. Heating at 50 degrees C failed to achieve a similar recovery of the clean-MS surface area value. Nonspecific mass loss tracked the increase in surface area as indirect evidence that naphthalene loss was the cause of the surface area increase. For the LB samples, aging at 100 degrees C produced a slight decrease in surface area and mass while aging at 250 degrees C caused the surface area to increase roughly threefold while the mass decreased by approximately 1%. These results suggest that, under moderate heating and over the time scale of this investigation, there is a redistribution of the complex contaminant mixture on the solid matrix. Greater temperatures remove mass more efficiently and therefore exhibited the surface area increase expected in this experiment.

Histochemical changes of occlusal surface enamel of permanent teeth, where dental caries is questionable vs sound enamel surfaces.

PubMed

Michalaki, M; Oulis, C J; Pandis, N; Eliades, G

2016-12-01

This in vitro study was to classify questionable for caries occlusal surfaces (QCOS) of permanent teeth according to ICDAS codes 1, 2, and 3 and to compare them in terms of enamel mineral composition with the areas of sound tissue of the same tooth. Partially impacted human molars (60) extracted for therapeutic reasons with QCOS were used in the study, photographed via a polarised light microscope and classified according to the ICDAS II (into codes 1, 2, or 3). The crowns were embedded in clear self-cured acrylic resin and longitudinally sectioned at the levels of the characterised lesions and studied by SEM/EDX, to assess enamel mineral composition of the QCOS. Univariate and multivariate random effect regressions were used for Ca (wt%), P (wt%), and Ca/P (wt%). The EDX analysis indicated changes in the Ca and P contents that were more prominent in ICDAS-II code 3 lesions compared to codes 1 and 2 lesions. In these lesions, Ca (wt%) and P (wt%) concentrations were significantly decreased (p = 0.01) in comparison with sound areas. Ca and P (wt%) contents were significantly lower (p = 0.02 and p = 0.01 respectively) for code 3 areas in comparison with codes 1 and 2 areas. Significantly higher (p = 0.01) Ca (wt%) and P (wt%) contents were found on sound areas compared to the lesion areas. The enamel of occlusal surfaces of permanent teeth with ICDAS 1, 2, and 3 lesions was found to have different Ca/P compositions, necessitating further investigation on whether these altered surfaces might behave differently on etching preparation before fissure sealant placement, compared to sound surfaces.

Hydrological Response to Land Cover Changes and Human Activities in Arid Regions Using a Geographic Information System and Remote Sensing

PubMed Central

Mahmoud, Shereif H.; Alazba, A. A.

2015-01-01

The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities. PMID:25923712

Comparison of Tibiofemoral Contact Mechanics After Various Transtibial and All-Inside Fixation Techniques for Medial Meniscus Posterior Root Radial Tears in a Porcine Model.

PubMed

Chung, Kyu Sung; Choi, Choong Hyeok; Bae, Tae Soo; Ha, Jeong Ku; Jun, Dal Jae; Wang, Joon Ho; Kim, Jin Goo

2018-04-01

To compare tibiofemoral contact mechanics after fixation for medial meniscus posterior root radial tears (MMPRTs). Seven fresh knees from mature pigs were used. Each knee was tested under 5 conditions: normal knee, MMPRT, pullout fixation with simple sutures, fixation with modified Mason-Allen sutures, and all-inside fixation using Fastfix 360. The peak contact pressure and contact surface area were evaluated using a capacitive sensor positioned between the meniscus and tibial plateau, under a 1,000-N compression force, at different flexion angles (0°, 30°, 60°, and 90°). The peak contact pressure was significantly higher in MMPRTs than in normal knees (P = .018). Although the peak contact pressure decreased significantly after fixation at all flexion angles (P = .031), it never recovered to the values noted in the normal meniscus. No difference was observed among fixation groups (P = .054). The contact surface area was significantly lower in MMPRTs than in the normal meniscus (P = .018) and increased significantly after fixation at all flexion angles (P = .018) but did not recover to within normal limits. For all flexion angles except 60°, the contact surface area was significantly higher for fixation with Mason-Allen sutures than for fixation with simple sutures or all-inside fixation (P = .027). At 90° of flexion, the contact surface area was significantly better for fixation with simple sutures than for all-inside fixation (P = .031). The peak contact pressure and contact surface area improved significantly after fixation, regardless of the fixation method, but did not recover to the levels noted in the normal meniscus after any type of fixation. Among the fixation methods evaluated in this time 0 study, fixation using modified Mason-Allen sutures provided a superior contact surface area compared with that noted after fixation using simple sutures or all-inside fixation, except at 60° of flexion. However, this study had insufficient power to accurately detect the differences between the outcomes of various fixation methods. Our results in a porcine model suggest that fixation can restore tibiofemoral contact mechanics in MMPRT and that fixation with a locking mechanism leads to superior biomechanical properties. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Release of ICTP and CTX telopeptides from demineralized dentin matrices: Effect of time, mass and surface area.

PubMed

Turco, Gianluca; Cadenaro, Milena; Maravić, Tatjana; Frassetto, Andrea; Marsich, Eleonora; Mazzoni, Annalisa; Di Lenarda, Roberto; Tay, Franklin R; Pashley, David H; Breschi, Lorenzo

2018-03-01

The present study evaluated the influence of time, mass and surface area of demineralized dentin collagen matrices on telopeptides release. The hypotheses tested were that the rates of ICTP and CTX release by matrix bound endogenous proteases are 1) not time-dependent, 2) unrelated to specimen mass, 3) unrelated to specimen surface area. Non-carious human molars (N=24) were collected and randomly assigned to three groups. Dentin slabs with three different thicknesses: 0.37mm, 0.75mm, and 1.50mm were completely demineralized and stored in artificial saliva for one week. Collagen degradation was evaluated by sampling storage media for ICTP and CTX telopeptidases. Activity of MMPs in the aging medium was evaluated using fluorometric activity assay kit. A statistically significant (p<0.05) decrease in the release of both ICTP and CTX fragments over time was observed irrespective of the specimen thickness. When data were normalized by the specimen mass, no significant differences were observed. Releases of ICTP and CTX were significantly related to the aging time as a function of surface area for the first 12h. Total MMP activity, mainly related to MMP-2 and -9, decreased with time (p<0.05). Because the release of collagen fragments was influenced by specimen storage time and surface area, it is likely that cleaved collagen fragments closer to the specimen surface diffuse into the incubation medium; those further away from the exposed surface are still entrapped within the demineralized dentin matrix. Bound MMPs can only degrade the substrate within the limited zone of their molecular mobility. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Darkening effect on AZ31B magnesium alloy surface induced by nanosecond pulse Nd:YAG laser

NASA Astrophysics Data System (ADS)

Guan, Y. C.; Zhou, W.; Zheng, H. Y.; Li, Z. L.

2013-09-01

Permanent darkening effect was achieved on surface of AZ31B Mg alloy irradiated with nanosecond pulse Nd:YAG laser, and special attention was made to examine how surface structure as well as oxidation affect the darkening effect. Experiments were carried out to characterize morphological evolution and chemical composition of the irradiated areas by optical reflection spectrometer, Talysurf surface profiler, SEM, EDS, and XPS. The darkening effect was found to be occurred at the surface under high laser energy. Optical spectra showed that the induced darkening surface was uniform over the spectral range from 200 nm to 1100 nm. SEM and surface profiler showed that surface morphology of darkening areas consisted of large number of micron scale cauliflower-like clusters and protruding particles. EDS and XPS showed that compared to non-irradiated area, oxygen content at the darkening areas increased significantly. It was proposed a mechanism that involved trapping of light in the surface morphology and chemistry variation of irradiated areas to explain the laser-induced darkening effect on AZ31B Mg alloy.

HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution

NASA Technical Reports Server (NTRS)

Moore, D. G. (Principal Investigator); Heilman, J.; Beutler, G.

1978-01-01

The author has identified the following significant results. In early April 1978, heavy spring runoff from snowmelt caused significant flooding along a portion of the Big Sioux River Basin in southeastern South Dakota. The flooded area was visible from surrounding areas on a May 15 HCMM IR test image. On May 15, the flood waters had receded but an area of anomalous residual high soil moisture remained. The high soil moisture area was not visible on a HCMM day visible test image of the same scene, or on LANDSAT imagery. To evaluate the effect of water table depth on surface temperatures, thermal scanner data collected on September 5 and 6, 1978 at approximate HCMM overpass times at an altitude of 3650 m were analyzed. Apparent surface temperatures measured by the scanner included emittance contributions from soil surface and the land cover. Results indicated that the shallow water tables produced a damping of the amplitude of the diurnal surface temperature wave.

The influence of anthropometric, kinematic and energetic variables and gender on swimming performance in youth athletes.

PubMed

Morais, Jorge E; Garrido, Nuno D; Marques, Mário C; Silva, António J; Marinho, Daniel A; Barbosa, Tiago M

2013-12-18

(i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers' anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1-2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1-2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance, anthropometrics, kinematics and energetics between boys and girls; (ii) swimmers with best performance are taller, have higher surface areas and better stroke mechanics; (iii) there are non-significant interactions between sports level and gender for anthropometrics, kinematics and energetics.

Early postoperative changes of the foveal surface in epiretinal membranes: comparison of 23-gauge macular surgery with air vs. balanced salt solution.

PubMed

Leitritz, Martin A; Ziemssen, Focke; Voykov, Bogomil; Dimopoulos, Spyridon; Zobor, Ditta; Bartz-Schmidt, Karl U; Gelisken, Faik

2014-08-01

To analyze the foveal surface using binary image analysis after spectral-domain optical coherence tomography (SD-OCT) following 23-gauge macular surgery in epiretinal membranes (ERM) using either air tamponade (AIR) or balanced salt solution (BSS). One hundred twenty-four eyes (124 patients) with ERM that had undergone membrane peeling with installation of air or BSS were analyzed retrospectively. Ophthalmic examination was performed at baseline and 3 months. The foveal area and surface symmetry, area matched thickness, area matched contour, and best-corrected visual acuity (BCVA). The OCT images were analyzed after binary conversion with ImageJ software. Eighty eyes (80 patients) of 124 screened patients were included (AIR group: 39 patients, BSS group: 41 patients). Median follow-up time was 14 weeks (range, 9-19 weeks). Three months after surgery, the median horizontal area decreased significantly in both groups (p < 0.0001). At follow-up, the foveal surface symmetry values for the BSS group (median, 22.73 μm, range, 0-153) were significantly lower than for the AIR group (median, 23.95 μm, range, 0-160.43) (p < 0.0001). The area-matched thickness increased significantly in both groups (p < 0.001). The AIR group showed a significant increase of the area matched contour for the nasal located measurement-areas N1 (p < 0.0003), N2 (p < 0.0079), N3 (p < 0.007). The BSS group showed a significant increase of the area-matched contour for the measurement areas N1 (p < 0.019), N2 (p < 0.0014), and N4 (p < 0.022). After surgery, median BCVA for both groups increased significantly to 0.3 logMAR. The analysis of early contour changes after ERM surgery was technically possible. Long-term data have to be looked at before the clinical impact of this methodology can be estimated. Although there were no big differences between both groups (AIR vs. BSS), this could change within a longer and more representative follow-up.

A feasible strategy to balance the crystallinity and specific surface area of metal oxide nanocrystals

NASA Astrophysics Data System (ADS)

Zhang, Q. P.; Xu, X. N.; Liu, Y. T.; Xu, M.; Deng, S. H.; Chen, Y.; Yuan, H.; Yu, F.; Huang, Y.; Zhao, K.; Xu, S.; Xiong, G.

2017-04-01

Practical, efficient synthesis of metal oxide nanocrystals with good crystallinity and high specific surface area by a modified polymer-network gel method is demonstrated, taking ZnO nanocrystals as an example. A novel stepwise heat treatment yields significant improvement in crystal quality. Such nanophase materials can effectively degrade common organic dyes under solar radiation and can perform very well in photo-assisted detection of NO2 gas. Other typical metal oxide nanocrystals with good crystallinity and high specific surface area were also synthesized successfully under similar conditions. This work provides a general strategy for the synthesis of metal oxide nanocrystals, balancing the crystallinity and specific surface area.

Location of Bare Soil Surface and Soil Line on the RED-NIR Spectral Plane

NASA Astrophysics Data System (ADS)

Koroleva, P. V.; Rukhovich, D. I.; Rukhovich, A. D.; Rukhovich, D. D.; Kulyanitsa, A. L.; Trubnikov, A. V.; Kalinina, N. V.; Simakova, M. S.

2017-12-01

Soil as a separate natural body occupies certain area with its own set of spectral characteristics within the RED-NIR spectral space. This is an ellipse-shaped area, and its semi-major axis is the soil line for a satellite image. The spectral area for a bare soil surface is neighboring to the areas of black carbon, straw, vegetating plants, and missing RED-NIR values. A reliable separation of the bare soil surface within the spectral space is possible with the technology of spectral neighborhood of soil line. The accuracy of this method is 90%. The determination of the bare soil surface using vegetation indices, both relative (NDVI), and perpendicular (PVI), is incorrect; the accuracy of these methods does not exceed 65%, and for most of the survey seasons it may be lower than 50%. The flat part of the "tasseled cap" described as the soil line, is not a synonym for the area of the bare soil surface. The bare soil surface on the RED-NIR plots occupies significantly smaller areas than the area of soil line according to Kauth and Thomas.

The effects of green areas on air surface temperature of the Kuala Lumpur city using WRF-ARW modelling and Remote Sensing technique

NASA Astrophysics Data System (ADS)

Isa, N. A.; Mohd, W. M. N. Wan; Salleh, S. A.; Ooi, M. C. G.

2018-02-01

Matured trees contain high concentration of chlorophyll that encourages the process of photosynthesis. This process produces oxygen as a by-product and releases it into the atmosphere and helps in lowering the ambient temperature. This study attempts to analyse the effect of green area on air surface temperature of the Kuala Lumpur city. The air surface temperatures of two different dates which are, in March 2006 and March 2016 were simulated using the Weather Research and Forecasting (WRF) model. The green area in the city was extracted using the Normalized Difference Vegetation Index (NDVI) from two Landsat satellite images. The relationship between the air surface temperature and the green area were analysed using linear regression models. From the study, it was found that, the green area was significantly affecting the distribution of air temperature within the city. A strong negative correlation was identified through this study which indicated that higher NDVI values tend to have lower air surface temperature distribution within the focus study area. It was also found that, different urban setting in mixed built-up and vegetated areas resulted in different distributions of air surface temperature. Future studies should focus on analysing the air surface temperature within the area of mixed built-up and vegetated area.

Volume and contact surface area analysis of bony tunnels in single and double bundle anterior cruciate ligament reconstruction using autograft tendons: in vivo three-dimensional imaging analysis.

PubMed

Yang, Jae-Hyuk; Chang, Minho; Kwak, Dai-Soon; Wang, Joon Ho

2014-09-01

Regarding reconstruction surgery of the anterior cruciate ligament (ACL), there is still a debate whether to perform a single bundle (SB) or double bundle (DB) reconstruction. The purpose of this study was to analyze and compare the volume and surface area of femoral and tibial tunnels during transtibial SB versus transportal DB ACL reconstruction. A consecutive series of 26 patients who underwent trantibial SB ACL reconstruction and 27 patients with transportal DB ACL reconstruction using hamstring autograft from January 2010 to October 2010 were included in this study. Three-dimensional computed tomography (3D-CT) was taken within one week after operation. The CT bone images were segmented with use of Mimics software v14.0. The obtained digital images were then imported in the commercial package Geomagic Studio v10.0 and SketchUp Pro v8.0 for processing. The femoral and tibial tunnel lengths, diameters, volumes and surface areas were evaluated. A comparison between the two groups was performed using the independent-samples t-test. A p-value less than the significance value of 5% (p < 0.05) was considered statistically significant. Regarding femur tunnels, a significant difference was not found between the tunnel volume for SB technique (1,496.51 ± 396.72 mm(3)) and the total tunnel volume for DB technique (1,593.81 ± 469.42 mm(3); p = 0.366). However, the total surface area for femoral tunnels was larger in DB technique (919.65 ± 201.79 mm(2)) compared to SB technique (810.02 ± 117.98 mm(2); p = 0.004). For tibia tunnels, there was a significant difference between tunnel volume for the SB technique (2,070.43 ± 565.07 mm(3)) and the total tunnel volume for the DB technique (2,681.93 ± 668.09 mm(3); p ≤ 0.001). The tibial tunnel surface area for the SB technique (958.84 ± 147.50 mm(2)) was smaller than the total tunnel surface area for the DB technique (1,493.31 ± 220.79 mm(2); p ≤ 0.001). Although the total femoral tunnel volume was similar between two techniques, the total surface area was larger in the DB technique. For the tibia, both total tunnel volume and the surface area were larger in DB technique.

Enhancement of sediment phosphorus release during a tunnel construction across an urban lake (Lake Donghu, China).

PubMed

Wang, Siyang; Li, Hui; Xiao, Jian; Zhou, Yiyong; Song, Chunlei; Bi, Yonghong; Cao, Xiuyun

2016-09-01

Tunnel construction in watershed area of urban lakes would accelerate eutrophication by inputting nutrients into them, while mechanisms underlying the internal phosphorus cycling as affected by construction events are scarcely studied. Focusing on two main pathways of phosphorus releasing from sediment (enzymatic mineralization and anaerobic desorption), spatial and temporal variations in phosphorus fractionation, and activities of extracellular enzymes (alkaline phosphatase, β-1,4-glucosidase, leucine aminopeptidase, dehydrogenase, lipase) in sediment were examined, together with relevant parameters in interstitial and surface waters in a Chinese urban lake (Lake Donghu) where a subaqueous tunnel was constructed across it from October 2013 to July 2014. Higher alkaline phosphatase activity (APA) indicated phosphorus deficiency for phytoplankton, as illustrated by a significantly negative relationship between APA and concentration of dissolved total phosphorus (DTP). Noticeably, in the construction area, APAs in both sediment and surface water were significantly lower than those in other relevant basins, suggesting a phosphorus supply from some sources in this area. In parallel, its sediment gave the significantly lower iron-bound phosphorus (Fe(OOH)∼P) content, coupled with significantly higher ratio of iron (II) to total iron content (Fe(2+)/TFe) and dehydrogenase activities (DHA). Contrastingly, difference in the activities of sediment hydrolases was not significant between the construction area and other basins studied. Thus, in the construction area, subsidy of bioavailable phosphorus from sediment to surface water was attributable to the anaerobic desorption of Fe(OOH)∼P rather than enzymatic mineralization. Finally, there existed a significantly positive relationship between chlorophyll a concentration in surface water and Fe(OOH)∼P content in sediment. In short, construction activities within lakes may interrupt cycling patterns of phosphorus across sediment-water interface by enhancing release of redox-sensitive phosphate, and thereby facilitating phytoplankton growth in water column.

Respiratory and olfactory turbinal size in canid and arctoid carnivorans.

PubMed

Green, Patrick A; Van Valkenburgh, Blaire; Pang, Benison; Bird, Deborah; Rowe, Timothy; Curtis, Abigail

2012-12-01

Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues. © 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.

Mass or total surface area with aerosol size distribution as exposure metrics for inflammatory, cytotoxic and oxidative lung responses in rats exposed to titanium dioxide nanoparticles.

PubMed

Noël, A; Truchon, G; Cloutier, Y; Charbonneau, M; Maghni, K; Tardif, R

2017-04-01

There is currently no consensus on the best exposure metric(s) for expressing nanoparticle (NP) dose. Although surface area has been extensively studied for inflammatory responses, it has not been as thoroughly validated for cytotoxicity or oxidative stress effects. Since inhaled NPs deposit and interact with lung cells based on agglomerate size, we hypothesize that mass concentration combined with aerosol size distribution is suitable for NP risk assessment. The objective of this study was to evaluate different exposure metrics for inhaled 5 nm titanium dioxide aerosols composed of small (SA < 100 nm) or large (LA > 100 nm) agglomerates at 2, 7, and 20 mg/m 3 on rat lung inflammatory, cytotoxicity, and oxidative stress responses. We found a significant positive correlation ( r = 0.98, p < 0.01) with the inflammatory reaction, measured by the number of neutrophils and the mass concentration when considering all six (SA + LA) aerosols. This correlation was similar ( r = 0.87) for total surface area. Regarding cytotoxicity and oxidative stress responses, measured by lactate dehydrogenase and 8-isoprostane, respectively, and mass or total surface area as an exposure metric, we observed significant positive correlations only with SA aerosols for both the mass concentration and size distribution ( r > 0.91, p < 0.01), as well as for the total surface area ( r > 0.97, p < 0.01). These data show that mass or total surface area concentrations alone are insufficient to adequately predict oxidant and cytotoxic pulmonary effects. Overall, our study indicates that considering NP size distribution along with mass or total surface area concentrations contributes to a more mechanistic discrimination of pulmonary responses to NP exposure.

Respiratory and olfactory turbinal size in canid and arctoid carnivorans

PubMed Central

Green, Patrick A; Valkenburgh, Blaire; Pang, Benison; Bird, Deborah; Rowe, Timothy; Curtis, Abigail

2012-01-01

Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues. PMID:23035637

Thermal maps of young women and men

NASA Astrophysics Data System (ADS)

Chudecka, Monika; Lubkowska, Anna

2015-03-01

The objective was to use thermal imaging (ThermaCAM SC500) as an effective tool in establishing a thermal map of young participants, with a high diagnostic value for medicine, physiotherapy and sport. A further aim was to establish temperature distributions and ranges on the body surface of the young women and men as standard temperatures for the examined age group, taking into account BMI, body surface area and selected parameters of body fat distribution. The participants included young, healthy and physically active women (n = 100) and men (n = 100). In the women and men, the highest Tmean temperatures were found on the trunk. The warmest were the chest and upper back, then the lower back and abdomen. The lowest Tmean were found in the distal parts of the body, especially on the lower limbs. The results showed that only in the area of the chest was Tmean significantly higher in women than in men. In the areas of the hands (front and back) Tmean were similar for women and men. In the other analyzed body surface areas, Tmean were significantly lower in women. Research showed significant differences in body surface temperature between the women and men. Among the analyzed characteristics, Tmean in the chest, upper back, abdomen, lower back (both in women and men) were mainly correlated with BMI and PBF; the correlations were negative. Difficulties in interpreting changes in temperature in selected body areas in people with various conditions can be associated with the lack of studies on large and representative populations of healthy individuals with normal weight/height parameters. Therefore, it seems that this presented research is a significant practical and cognitive contribution to knowledge on thermoregulation, and may therefore be used as a reference for other studies using thermal imaging in the evaluation of changes in body surface temperatures.

Evaluating blood-brain barrier permeability in delayed cerebral infarction after aneurysmal subarachnoid hemorrhage.

PubMed

Ivanidze, J; Kesavabhotla, K; Kallas, O N; Mir, D; Baradaran, H; Gupta, A; Segal, A Z; Claassen, J; Sanelli, P C

2015-05-01

Patients with SAH are at increased risk of delayed infarction. Early detection and treatment of delayed infarction remain challenging. We assessed blood-brain barrier permeability, measured as permeability surface area product, by using CTP in patients with SAH with delayed infarction. We performed a retrospective study of patients with SAH with delayed infarction on follow-up NCCT. CTP was performed before the development of delayed infarction. CTP data were postprocessed into permeability surface area product, CBF, and MTT maps. Coregistration was performed to align the infarcted region on the follow-up NCCT with the corresponding location on the CTP maps obtained before infarction. Permeability surface area product, CBF, and MTT values were then obtained in the location of the subsequent infarction. The contralateral noninfarcted region was compared with the affected side in each patient. Wilcoxon signed rank tests were performed to determine statistical significance. Clinical data were collected at the time of CTP and at the time of follow-up NCCT. Twenty-one patients with SAH were included in the study. There was a statistically significant increase in permeability surface area product in the regions of subsequent infarction compared with the contralateral control regions (P < .0001). However, CBF and MTT values were not significantly different in these 2 regions. Subsequent follow-up NCCT demonstrated new delayed infarction in all 21 patients, at which time 38% of patients had new focal neurologic deficits. Our study reveals a statistically significant increase in permeability surface area product preceding delayed infarction in patients with SAH. Further investigation of early permeability changes in SAH may provide new insights into the prediction of delayed infarction. © 2015 by American Journal of Neuroradiology.

Porous silicon structures with high surface area/specific pore size

DOEpatents

Northrup, M.A.; Yu, C.M.; Raley, N.F.

1999-03-16

Fabrication and use of porous silicon structures to increase surface area of heated reaction chambers, electrophoresis devices, and thermopneumatic sensor-actuators, chemical preconcentrates, and filtering or control flow devices. In particular, such high surface area or specific pore size porous silicon structures will be useful in significantly augmenting the adsorption, vaporization, desorption, condensation and flow of liquids and gases in applications that use such processes on a miniature scale. Examples that will benefit from a high surface area, porous silicon structure include sample preconcentrators that are designed to adsorb and subsequently desorb specific chemical species from a sample background; chemical reaction chambers with enhanced surface reaction rates; and sensor-actuator chamber devices with increased pressure for thermopneumatic actuation of integrated membranes. Examples that benefit from specific pore sized porous silicon are chemical/biological filters and thermally-activated flow devices with active or adjacent surfaces such as electrodes or heaters. 9 figs.

Porous silicon structures with high surface area/specific pore size

DOEpatents

Northrup, M. Allen; Yu, Conrad M.; Raley, Norman F.

1999-01-01

Fabrication and use of porous silicon structures to increase surface area of heated reaction chambers, electrophoresis devices, and thermopneumatic sensor-actuators, chemical preconcentrates, and filtering or control flow devices. In particular, such high surface area or specific pore size porous silicon structures will be useful in significantly augmenting the adsorption, vaporization, desorption, condensation and flow of liquids and gasses in applications that use such processes on a miniature scale. Examples that will benefit from a high surface area, porous silicon structure include sample preconcentrators that are designed to adsorb and subsequently desorb specific chemical species from a sample background; chemical reaction chambers with enhanced surface reaction rates; and sensor-actuator chamber devices with increased pressure for thermopneumatic actuation of integrated membranes. Examples that benefit from specific pore sized porous silicon are chemical/biological filters and thermally-activated flow devices with active or adjacent surfaces such as electrodes or heaters.

In-use catalyst surface area and its relation to HC conversion efficiency and FTP emissions

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

Donahue, K.S.; Sabourin, M.A.; Larson, R.E.

1986-01-01

Surface area data, steady-state hydrocarbon conversion efficiency data, and hydrocarbon emissions results have been determined for catalysts collected by the U.S. Environmental Protection Agency from properly maintained 1981 and 1982 model year vehicles. Catalysts covered in this study were limited to those with three-way-plus-oxidation monolith technologies. Catalyst surface areas were measured using the BET method, conversion efficiencies were measured on an exhaust gas generator, and emissions results were determined using the Urban Driving Schedule of the Federal Test Procedure. Results indicate that correlation of catalyst surface area data with hydrocarbon conversion efficiency data and hydrocarbon emissions results is significant formore » the sample studied.« less

A Mathematical Method to Calculate Tumor Contact Surface Area: An Effective Parameter to Predict Renal Function after Partial Nephrectomy.

PubMed

Hsieh, Po-Fan; Wang, Yu-De; Huang, Chi-Ping; Wu, Hsi-Chin; Yang, Che-Rei; Chen, Guang-Heng; Chang, Chao-Hsiang

2016-07-01

We proposed a mathematical formula to calculate contact surface area between a tumor and renal parenchyma. We examined the applicability of using contact surface area to predict renal function after partial nephrectomy. We performed this retrospective study in patients who underwent partial nephrectomy between January 2012 and December 2014. Based on abdominopelvic computerized tomography or magnetic resonance imaging, we calculated the contact surface area using the formula (2*π*radius*depth) developed by integral calculus. We then evaluated the correlation between contact surface area and perioperative parameters, and compared contact surface area and R.E.N.A.L. (Radius/Exophytic/endophytic/Nearness to collecting system/Anterior/Location) score in predicting a reduction in renal function. Overall 35, 26 and 45 patients underwent partial nephrectomy with open, laparoscopic and robotic approaches, respectively. Mean ± SD contact surface area was 30.7±26.1 cm(2) and median (IQR) R.E.N.A.L. score was 7 (2.25). Spearman correlation analysis showed that contact surface area was significantly associated with estimated blood loss (p=0.04), operative time (p=0.04) and percent change in estimated glomerular filtration rate (p <0.001). On multivariate analysis contact surface area and R.E.N.A.L. score independently affected percent change in estimated glomerular filtration rate (p <0.001 and p=0.03, respectively). On ROC curve analysis contact surface area was a better independent predictor of a greater than 10% change in estimated glomerular filtration rate compared to R.E.N.A.L. score (AUC 0.86 vs 0.69). Using this simple mathematical method, contact surface area was associated with surgical outcomes. Compared to R.E.N.A.L. score, contact surface area was a better predictor of functional change after partial nephrectomy. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Wireless Channel Characterization in the 5 GHz Microwave Landing System Extension Band for Airport Surface Areas

NASA Technical Reports Server (NTRS)

Matolak, David W.

2007-01-01

In this project final report, entitled "Wireless Channel Characterization in the 5 GHz Microwave Landing System Extension Band for Airport Surface Areas," we provide a detailed description and model representation for the wireless channel in the airport surface environment in this band. In this executive summary, we review report contents, describe the achieved objectives and major findings, and highlight significant conclusions and recommendations.

Pollution characteristics of surface runoff under different restoration types in manganese tailing wasteland.

PubMed

Wang, Jun; Cheng, Qingyu; Xue, Shengguo; Rajendran, Manikandan; Wu, Chuan; Liao, Jiaxin

2018-04-01

A great deal of manganese and associated heavy metals (such as Ni, Cu, Zn, Cd, Pb, etc.) was produced in manganese mining, smelting, and other processes and weathering and leaching of waste slag, which entered rainwater runoff by different means under the action of rainfall runoff. It caused heavy metal pollution in water environment to surrounding areas, and then environmental and human health risks were becoming increasingly serious. In the Xiangtan manganese mine, we studied the characteristics of nutritional pollutants and heavy metals by using the method of bounded runoff plots on the manganese tailing wasteland after carrying out some site treatments using three different approaches, such as (1) exposed tailings, the control treatment (ET), (2) external-soil amelioration and colonization of Cynodon dactylon (Linn.) Pers. turf (EC), and (3) external-soil amelioration and seedling seeding propagation of Cynodon dactylon (Linn.) Pers. (ES). The research showed that the maximum runoff occurred in 20,140,712 rainfall events, and the basic law of runoff was EC area > ET area > ES area in the same rainfall event. The concentration of total suspended solids (TSS) and chemical oxygen demand (COD) of three ecological restoration areas adopted the following rule: ET area > EC area > ES area. Nitrogen (N) existed mainly in the form of water soluble while phosphorus (P) was particulate. The highest concentrations of total nitrogen (TN) and total phosphorus (TP) were 11.57 ± 2.99 mg/L in the EC area and 1.42 ± 0.56 mg/L in the ET area, respectively. Cr, Ni, Pb, Zn, Mn, and Cu in surface runoff from three restoration types all exceeded the class V level of the environmental quality standard for surface water except Cu in EC and ES areas. Pollution levels of heavy metals in surface runoff from three restoration areas are shown as follows: ET area > EC area > ES area. There was a significant positive correlation between TSS and runoff, COD, and TP. And this correlation was significant between total dissolved nitrogen (TDN), TN, total dissolved phosphorus (TDP), and TP. The six heavy metals (Cu, Ni, Pb, Zn, Mn, and Cr) in surface runoff of different ecological restoration areas were strongly related to each other, and were significantly related to the TSS.

Granitic boulder erosion caused by chaparral wildfire: Implications for cosmogenic radionuclide dating of bedrock surfaces

USGS Publications Warehouse

Kendrick, Katherine J.; Camille Partin,; Graham, Robert C.

2016-01-01

Rock surface erosion by wildfire is significant and widespread but has not been quantified in southern California or for chaparral ecosystems. Quantifying the surface erosion of bedrock outcrops and boulders is critical for determination of age using cosmogenic radionuclide techniques, as even modest surface erosion removes the accumulation of the cosmogenic radionuclides and causes significant underestimate of age. This study documents the effects on three large granitic boulders following the Esperanza Fire of 2006 in southern California. Spalled rock fragments were quantified by measuring the removed rock volume from each measured boulder. Between 7% and 55% of the total surface area of the boulders spalled in this single fire. The volume of spalled material, when normalized across the entire surface area, represents a mean surface lowering of 0.7–12.3 mm. Spalled material was thicker on the flanks of the boulders, and the height of the fire effects significantly exceeded the height of the vegetation prior to the wildfire. Surface erosion of boulders and bedrock outcrops as a result of wildfire spalling results in fresh surfaces that appear unaffected by chemical weathering. Such surfaces may be preferentially selected by researchers for cosmogenic surface dating because of their fresh appearance, leading to an underestimate of age.

New model for estimating the relationship between surface area and volume in the human body using skeletal remains.

PubMed

Kasabova, Boryana E; Holliday, Trenton W

2015-04-01

A new model for estimating human body surface area and body volume/mass from standard skeletal metrics is presented. This model is then tested against both 1) "independently estimated" body surface areas and "independently estimated" body volume/mass (both derived from anthropometric data) and 2) the cylindrical model of Ruff. The model is found to be more accurate in estimating both body surface area and body volume/mass than the cylindrical model, but it is more accurate in estimating body surface area than it is for estimating body volume/mass (as reflected by the standard error of the estimate when "independently estimated" surface area or volume/mass is regressed on estimates derived from the present model). Two practical applications of the model are tested. In the first test, the relative contribution of the limbs versus the trunk to the body's volume and surface area is compared between "heat-adapted" and "cold-adapted" populations. As expected, the "cold-adapted" group has significantly more of its body surface area and volume in its trunk than does the "heat-adapted" group. In the second test, we evaluate the effect of variation in bi-iliac breadth, elongated or foreshortened limbs, and differences in crural index on the body's surface area to volume ratio (SA:V). Results indicate that the effects of bi-iliac breadth on SA:V are substantial, while those of limb lengths and (especially) the crural index are minor, which suggests that factors other than surface area relative to volume are driving morphological variation and ecogeographical patterning in limb prorportions. © 2014 Wiley Periodicals, Inc.

Cortical Abnormalities Associated With Pediatric and Adult Obsessive-Compulsive Disorder: Findings From the ENIGMA Obsessive-Compulsive Disorder Working Group.

PubMed

Boedhoe, Premika S W; Schmaal, Lianne; Abe, Yoshinari; Alonso, Pino; Ameis, Stephanie H; Anticevic, Alan; Arnold, Paul D; Batistuzzo, Marcelo C; Benedetti, Francesco; Beucke, Jan C; Bollettini, Irene; Bose, Anushree; Brem, Silvia; Calvo, Anna; Calvo, Rosa; Cheng, Yuqi; Cho, Kang Ik K; Ciullo, Valentina; Dallaspezia, Sara; Denys, Damiaan; Feusner, Jamie D; Fitzgerald, Kate D; Fouche, Jean-Paul; Fridgeirsson, Egill A; Gruner, Patricia; Hanna, Gregory L; Hibar, Derrek P; Hoexter, Marcelo Q; Hu, Hao; Huyser, Chaim; Jahanshad, Neda; James, Anthony; Kathmann, Norbert; Kaufmann, Christian; Koch, Kathrin; Kwon, Jun Soo; Lazaro, Luisa; Lochner, Christine; Marsh, Rachel; Martínez-Zalacaín, Ignacio; Mataix-Cols, David; Menchón, José M; Minuzzi, Luciano; Morer, Astrid; Nakamae, Takashi; Nakao, Tomohiro; Narayanaswamy, Janardhanan C; Nishida, Seiji; Nurmi, Erika; O'Neill, Joseph; Piacentini, John; Piras, Fabrizio; Piras, Federica; Reddy, Y C Janardhan; Reess, Tim J; Sakai, Yuki; Sato, Joao R; Simpson, H Blair; Soreni, Noam; Soriano-Mas, Carles; Spalletta, Gianfranco; Stevens, Michael C; Szeszko, Philip R; Tolin, David F; van Wingen, Guido A; Venkatasubramanian, Ganesan; Walitza, Susanne; Wang, Zhen; Yun, Je-Yeon; Thompson, Paul M; Stein, Dan J; van den Heuvel, Odile A

2018-05-01

Brain imaging studies of structural abnormalities in OCD have yielded inconsistent results, partly because of limited statistical power, clinical heterogeneity, and methodological differences. The authors conducted meta- and mega-analyses comprising the largest study of cortical morphometry in OCD ever undertaken. T 1 -weighted MRI scans of 1,905 OCD patients and 1,760 healthy controls from 27 sites worldwide were processed locally using FreeSurfer to assess cortical thickness and surface area. Effect sizes for differences between patients and controls, and associations with clinical characteristics, were calculated using linear regression models controlling for age, sex, site, and intracranial volume. In adult OCD patients versus controls, we found a significantly lower surface area for the transverse temporal cortex and a thinner inferior parietal cortex. Medicated adult OCD patients also showed thinner cortices throughout the brain. In pediatric OCD patients compared with controls, we found significantly thinner inferior and superior parietal cortices, but none of the regions analyzed showed significant differences in surface area. However, medicated pediatric OCD patients had lower surface area in frontal regions. Cohen's d effect sizes varied from -0.10 to -0.33. The parietal cortex was consistently implicated in both adults and children with OCD. More widespread cortical thickness abnormalities were found in medicated adult OCD patients, and more pronounced surface area deficits (mainly in frontal regions) were found in medicated pediatric OCD patients. These cortical measures represent distinct morphological features and may be differentially affected during different stages of development and illness, and possibly moderated by disease profile and medication.

Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

NASA Astrophysics Data System (ADS)

Cieśla, Jolanta; Sokołowska, Zofia; Witkowska-Walczak, Barbara; Skic, Kamil

2018-01-01

Water vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0-1 range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

PubMed Central

Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

2016-01-01

Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems. PMID:27656062

Surface area-volume ratios in insects.

PubMed

Kühsel, Sara; Brückner, Adrian; Schmelzle, Sebastian; Heethoff, Michael; Blüthgen, Nico

2017-10-01

Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have not been measured explicitly in this context. We quantified surface area-volume (SA/V) ratios for the first time using 3D surface models based on a structured light scanning method for 126 species of pollinating insects from 4 orders (Diptera, Hymenoptera, Lepidoptera, and Coleoptera). Water loss of 67 species was measured gravimetrically at very dry conditions for 2 h at 15 and 30 °C to demonstrate the applicability of the new 3D surface measurements and relevance for predicting the performance of insects. Quantified SA/V ratios significantly explained the variation in water loss across species, both directly or after accounting for isometric scaling (residuals of the SA/V ∼ mass 2/3 relationship). Small insects with a proportionally larger surface area had the highest water loss rates. Surface scans of insects to quantify allometric SA/V ratios thus provide a promising method to predict physiological responses, improving the potential of body mass isometry alone that assume geometric similarity. © 2016 Institute of Zoology, Chinese Academy of Sciences.

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.

The effects of sorting by aeolian processes on the geochemical characteristics of surface materials: a wind tunnel experiment

NASA Astrophysics Data System (ADS)

Wang, Xunming; Lang, Lili; Hua, Ting; Zhang, Caixia; Li, Hui

2018-03-01

The geochemical characteristics of aeolian and surface materials in potential source areas of dust are frequently employed in environmental reconstructions as proxies of past climate and as source tracers of aeolian sediments deposited in downwind areas. However, variations in the geochemical characteristics of these aeolian deposits that result from near-surface winds are currently poorly understood. In this study, we collected surface samples from the Ala Shan Plateau (a major potential dust source area in Central Asia) to determine the influence of aeolian processes on the geochemical characteristics of aeolian transported materials. Correlation analyses show that compared with surface materials, the elements in transported materials (e.g., Cu, As, Pb, Mn, Zn, Al, Ca, Fe, Ga, K, Mg, P, Rb, Co, Cr, Na, Nb, Si, and Zr) were subjected to significant sorting by aeolian processes, and the sorting also varied among different particle size fractions and elements. Variations in wind velocity were significantly correlated with the contents of Cr, Ga, Sr, Ca, Y, Nd, Zr, Nb, Ba, and Al, and with the Zr/Al, Zr/Rb, K/Ca, Sr/Ca, Rb/Sr, and Ca/Al ratios. Given the great variation in the geochemical characteristics of materials transported under different aeolian processes relative to those of the source materials, these results indicate that considerable uncertainty may be introduced to analyses by using surface materials to trace the potential source areas of aeolian deposits that accumulate in downwind areas.

Investigation of laser-fired point contacts on KOH structured laser-crystallized silicon by conductive atomic force microscopy

NASA Astrophysics Data System (ADS)

Gref, Orman; Weizman, Moshe; Rhein, Holger; Gabriel, Onno; Gernert, Ulrich; Schlatmann, Rutger; Boit, Christian; Friedrich, Felice

2016-06-01

A conductive atomic force microscope is used to study the local topography and conductivity of laser-fired aluminum contacts on KOH-structured multicrystalline silicon surfaces. A significant increase in conductivity is observed in the laser-affected area. The area size and spatial uniformity of this enhanced conductivity depends on the laser energy fluence. The laser-affected area shows three ring-shaped regimes of different conductance depending on the local aluminum and oxygen concentration. Finally, it was found that the topographic surface structure determined by the silicon grain orientation does not significantly affect the laser-firing process.

Geohydrology and susceptibility of major aquifers to surface contamination in Alabama; area 12

USGS Publications Warehouse

Scott, J.C.; Cobb, R.H.

1988-01-01

This report delineates and describes the geohydrology and susceptibility of major aquifers to contamination in Coffee, Dale, Henry, Houston, and Geneva Counties, Alabama. The major aquifers are the Upper Floridan, Lisbon, Nanafalia-Clayton, and Providence-Ripley aquifers. Estimated groundwater withdrawals for public water supplies are about 42 million gal/day. Maximum withdrawals for irrigation are 15 to 20 million gal/day. Withdrawals for self-supplied industrial and domestic uses are estimated to be 3 and 2.5 million gal/day, respectively. Long-term withdrawals of water from the Nanafalia-Clayton aquifer have resulted in significant declines in the potentiometric surface in Coffee, Dale, and Houston Counties. Significant declines in the potentiometric surfaces of the other major aquifers are not apparent. Recharge areas for all major aquifers are susceptible to contamination, but the probability of contamination of the Lisbon, Nanafalia-Clayton, and Providence-Ripley aquifers is low because the recharge areas are remote from areas of withdrawal. The recharge area for the Floridan aquifer, which consists largely of flat, sandy farmland , coincides with the area of use. This area is highly susceptible to contamination from insecticides and herbicides. (USGS)

BET surface area distributions in polar stream sediments: Implications for silicate weathering in a cold-arid environment

USGS Publications Warehouse

Marra, Kristen R.; Elwood Madden, Megan E; Soreghan, Gerilyn S.; Hall, Brenda L

2014-01-01

BET surface area values are critical for quantifying the amount of potentially reactive sediments available for chemical weathering and ultimately, prediction of silicate weathering fluxes. BET surface area values of fine-grained (<62.5 μm) sediment from the hyporheic zone of polar glacial streams in the McMurdo Dry Valleys, Antarctica (Wright and Taylor Valleys) exhibit a wide range (2.5–70.6 m2/g) of surface area values. Samples from one (Delta Stream, Taylor Valley) of the four sampled stream transects exhibit high values (up to 70.6 m2/g), which greatly exceed surface area values from three temperate proglacial streams (0.3–12.1 m2/g). Only Clark stream in Wright Valley exhibits a robust trend with distance, wherein surface area systematically decreases (and particle size increases) in the mud fraction downstream, interpreted to reflect rapid dissolution processes in the weathering environment. The remaining transects exhibit a range in variability in surface area distributions along the length of the channel, likely related to variations in eolian input to exposed channel beds, adjacent snow drifts, and to glacier surfaces, where dust is trapped and subsequently liberated during summer melting. Additionally, variations in stream discharge rate, which mobilizes sediment in pulses and influences water:rock ratios, the origin and nature of the underlying drift material, and the contribution of organic acids may play significant roles in the production and mobilization of high-surface area sediment. This study highlights the presence of sediments with high surface area in cold-based glacier systems, which influences models of chemical denudation rates and the impact of glacial systems on the global carbon cycle.

Slippery Liquid-Infused Porous Surfaces and Droplet Transportation by Surface Acoustic Waves

NASA Astrophysics Data System (ADS)

Luo, J. T.; Geraldi, N. R.; Guan, J. H.; McHale, G.; Wells, G. G.; Fu, Y. Q.

2017-01-01

On a solid surface, a droplet of liquid will stick due to the capillary adhesion, and this causes low droplet mobility. To reduce contact line pinning, surface chemistry can be coupled to micro- and/or nanostructures to create superhydrophobic surfaces on which a droplet balls up into an almost spherical shape, thus, minimizing the contact area. Recent progress in soft matter has now led to alternative lubricant-impregnated surfaces capable of almost zero contact line pinning and high droplet mobility without causing droplets to ball up and minimize the contact area. Here we report an approach to surface-acoustic-wave- (SAW) actuated droplet transportation enabled using such a surface. These surfaces maintain the contact area required for efficient energy and momentum transfer of the wave energy into the droplet while achieving high droplet mobility and a large footprint, therefore, reducing the threshold power required to induce droplet motion. In our approach, we use a slippery layer of lubricating oil infused into a self-assembled porous hydrophobic layer, which is significantly thinner than the SAW wavelength, and avoid damping of the wave. We find a significant reduction (up to 85%) in the threshold power for droplet transportation compared to that using a conventional surface-treatment method. Moreover, unlike droplets on superhydrophobic surfaces, where interaction with the SAW induces a transition from a Cassie-Baxter state to a Wenzel state, the droplets on our liquid-impregnated surfaces remain in a mobile state after interaction with the SAW.

The cold and atmospheric-pressure air surface barrier discharge plasma for large-area sterilization applications

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

Wang Dacheng; Department of Aeronautics, Fujian Key Laboratory for Plasma and Magnetic Resonance, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen, Fujian 361005; Zhao Di

2011-04-18

This letter reports a stable air surface barrier discharge device for large-area sterilization applications at room temperature. This design may result in visually uniform plasmas with the electrode area scaled up (or down) to the required size. A comparison for the survival rates of Escherichia coli from air, N{sub 2} and O{sub 2} surface barrier discharge plasmas is presented, and the air surface plasma consisting of strong filamentary discharges can efficiently kill Escherichia coli. Optical emission measurements indicate that reactive species such as O and OH generated in the room temperature air plasmas play a significant role in the sterilizationmore » process.« less

Preliminary post-tsunami water quality survey in Phang-Nga province, southern Thailand.

PubMed

Tharnpoophasiam, Prapin; Suthisarnsuntorn, Usanee; Worakhunpiset, Suwalee; Charoenjai, Prasasana; Tunyong, Witawat; Phrom-In, Suvannee; Chattanadee, Siriporn

2006-01-01

This preliminary water quality survey was performed eight weeks after the tsunami hit Phang-Nga Province on 26 December 2004. Water samples collected from the affected area, 10 km parallel to the seaside, were compared with water samples from the control area approximately 4 km from the seaside, which the tsunami waves could not reach. These samples included 18 surface-water samples, 37 well-water samples, and 8 drinking-water samples, which were examined for microbiology and physical-chemical properties. The microbiological examinations focused on enteric bacteria, which were isolated by culture method, while physical-chemical properties comprised on-site testing for pH, salinity, dissolved oxygen (DO), conductivity and total dissolved solids (TDS) by portable electrochemical meter (Sens Ion 156). The results of the microbiological examinations showed that water samples in the affected areas were more contaminated with enteric bacteria than the control area: 45.4% of surface-water samples in the affected area, and 40.0% in the control; 19.0% of well-water samples in the affected area, and 7.7% in the control. All eight drinking-water samples were clear of enteric bacteria. Tests for physical-chemical properties showed that the salinity, pH, conductivity, and TDS of surface-water samples from the affected area were significantly higher than the control. The salinity, conductivity, and TDS of the well-water samples from the affected areas were also significantly greater than those from the control area. The surface and well water in the tsunami-affected area have been changed greatly and need improvement.

Sex determination using discriminant analysis of upper and lower extremity bones: New approach using the volume and surface area of digital model.

PubMed

Lee, U-Young; Kim, In-Beom; Kwak, Dai-Soon

2015-08-01

This study used 110 CT images taken from donated Korean cadavers to create 3-D models of the following upper and lower limb bones: the clavicle, scapula, humerus, radius, ulna, hip bone (os coxa), femur, patella (knee cap), tibia, talus, and calcaneus. In addition, the bone volume and surface area were calculated to determine sex differences using discriminant analysis. Significant sex differences were found in all bones with respect to volume and surface area (p<0.01). The order of volume was the same in females and males (femur>hip bone>tibia>humerus>scapula), although the order of surface area was different. The largest surface area in men was the femur and in women was the hip bone (p<0.01). An interesting finding of this study was that the ulna is the bone with the highest accuracy for sex determination (94%). When using the surface area of multiple bones, the maximum accuracy (99.4%) was achieved. The equation was as follows: (discriminant equation of surface area; female<0

Mass, surface area and number metrics in diesel occupational exposure assessment.

PubMed

Ramachandran, Gurumurthy; Paulsen, Dwane; Watts, Winthrop; Kittelson, David

2005-07-01

While diesel aerosol exposure assessment has traditionally been based on the mass concentration metric, recent studies have suggested that particle number and surface area concentrations may be more health-relevant. In this study, we evaluated the exposures of three occupational groups-bus drivers, parking garage attendants, and bus mechanics-using the mass concentration of elemental carbon (EC) as well as surface area and number concentrations. These occupational groups are exposed to mixtures of diesel and gasoline exhaust on a regular basis in various ratios. The three groups had significantly different exposures to workshift TWA EC with the highest levels observed in the bus garage mechanics and the lowest levels in the parking ramp booth attendants. In terms of surface area, parking ramp attendants had significantly greater exposures than bus garage mechanics, who in turn had significantly greater exposures than bus drivers. In terms of number concentrations, the exposures of garage mechanics exceeded those of ramp booth attendants by a factor of 5-6. Depending on the exposure metric chosen, the three occupational groups had quite different exposure rankings. This illustrates the importance of the choice of exposure metric in epidemiological studies. If these three occupational groups were part of an epidemiological study, depending on the metric used, they may or may not be part of the same similarly exposed group (SEG). The exposure rankings (e.g., low, medium, or high) of the three groups also changes with the metric used. If the incorrect metric is used, significant misclassification errors may occur.

Fibrinogen adsorption onto 316L stainless steel under polarized conditions.

PubMed

Gettens, Robert T T; Gilbert, Jeremy L

2008-04-01

Adsorption of the plasma protein fibrinogen onto electrically polarized 316L stainless steel was observed and quantified using both in situ and ex situ atomic force microscopy (AFM) techniques. Significant differences in fibrinogen adsorption were observed across voltages. Ex situ studies showed significantly lower area coverage (theta) and height of adsorbed Fb on cathodically polarized surfaces when compared to anodically polarized surfaces. Conformational differences in the protein may explain the distinctions in Fb surface area coverage (theta) and height between the anodic and cathodic cases. In situ studies showed significantly slower kinetics of Fb adsorption onto surfaces below -100 mV (vs. Ag/AgCl) compared to surfaces polarized above -100 mV. Electrochemical current density data showed large charge transfer processes (approximately 1 x 10(-5) to 1 x 10(-4) A/cm(2)) taking place on the 316L SS surfaces at voltages below -100 mV (vs. Ag/AgCl). These relatively large current densities point to flux of ionic species away from the surface as a major source of the reduction in adsorption kinetics rather than just hydrophilic or electrostatic effects. Copyright 2007 Wiley Periodicals, Inc.

Concentrations of Surface-Dust Metals in Native American Jewelry-Making Homes in Zuni Pueblo, New Mexico

PubMed Central

Gonzales, Melissa; Shah, Vallabh; Bobelu, Arlene; Qualls, Clifford; Natachu, Kathy; Bobelu, Jeanette; Jamon, Eunice; Neha, Donica; Paine, Susan; Zager, Philip

2013-01-01

This pilot study was conducted to identify the metals used by home-based Native American jewelry makers, to quantify the metals in dust samples taken from jewelers’ homes, and to compare these concentrations with background levels from control homes in which jewelry was not made. Participants were recruited from Zuni Pueblo, New Mexico. Surface dust samples were collected from the work and living areas of 20 jewelers’ homes, and from the living areas of 20 control homes. Silver, copper, tin, boron, nickel, zinc, lead, and cadmium were significantly higher in work areas than in living areas of jewelry-making homes (p≤ 0.02). Silver, copper, nickel, and antimony were significantly higher in living areas of jewelers’ homes compared with control homes (p ≤ 0.04). Ventilation measures did not effectively reduce metal concentrations in jewelers’ homes; concentrations in nonwork areas remained elevated. PMID:16201670

Frictional heterogeneities on carbonate-bearing normal faults: Insights from the Monte Maggio Fault, Italy

NASA Astrophysics Data System (ADS)

Carpenter, B. M.; Scuderi, M. M.; Collettini, C.; Marone, C.

2014-12-01

Observations of heterogeneous and complex fault slip are often attributed to the complexity of fault structure and/or spatial heterogeneity of fault frictional behavior. Such complex slip patterns have been observed for earthquakes on normal faults throughout central Italy, where many of the Mw 6 to 7 earthquakes in the Apennines nucleate at depths where the lithology is dominated by carbonate rocks. To explore the relationship between fault structure and heterogeneous frictional properties, we studied the exhumed Monte Maggio Fault, located in the northern Apennines. We collected intact specimens of the fault zone, including the principal slip surface and hanging wall cataclasite, and performed experiments at a normal stress of 10 MPa under saturated conditions. Experiments designed to reactivate slip between the cemented principal slip surface and cataclasite show a 3 MPa stress drop as the fault surface fails, then velocity-neutral frictional behavior and significant frictional healing. Overall, our results suggest that (1) earthquakes may readily nucleate in areas of the fault where the slip surface separates massive limestone and are likely to propagate in areas where fault gouge is in contact with the slip surface; (2) postseismic slip is more likely to occur in areas of the fault where gouge is present; and (3) high rates of frictional healing and low creep relaxation observed between solid fault surfaces could lead to significant aftershocks in areas of low stress drop.

Optimum BET surface areas for activated carbon produced from textile sewage sludges and its application as dye removal.

PubMed

Kacan, Erdal

2016-01-15

The purpose of this experimental study is to determine optimum preparation conditions for activated carbons obtained from textile sewage sludge (TSS) for removal of dyes from aqueous solutions. The textile sewage sludge activated carbon (TSSAC) was prepared by chemical activation with potassium hydroxide using Response Surface Methodology (RSM). The most influential factor on each experimental design responses was identified via ANNOVA analysis. Based on the central composite design (CCD), quadratic model was developed to correlate the preparation variables for one response which is the Brunauer-Emmelt-Teller (BET) surface area. RSM based on a three-variable CCD was used to determine the effect of pyrolyzed temperature (400-700 °C), carbonization time (45-180 min) and KOH: weight of TSS (wt%) impregnation ratio (0.5:1-1.5:1) on BET surface area. According to the results, pyrolyzed temperature and impregnation ratio were found as the significant factors for maximizing the BET surface area. The major effect which influences the BET surface area was found as pyrolyzed temperature. Both carbonization time and impregnation ratio of KOH had no significant effect. The optimum conditions for preparing TSSAC, based on response surface and contour plots, were found as follows: pyrolyzed temperature 700 °C, carbonization time of 45 min and chemical impregnation ratio of 0.5. The maximum and optimum BET surface area of TSSAC were found as 336 m(2)/g and 310.62 m(2)/g, respectively. Synozol Blue reactive (RSB) and Setapers Yellow-Brown (P2RFL) industrial textile dyes adsorption capacities were investigated. As expected the TSSAC which has the biggest BET surface area (336 m(2)/g) adsorbed dye best. The maximum (RSB) and (P2RFL) uptake capacities were found as 8.5383 mg/g and 5.4 mg/g, respectively. The results of this study indicated the applicability of TSSAC for removing industrial dyes from aqueous solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantifying object and material surface areas in residences

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

Hodgson, Alfred T.; Ming, Katherine Y.; Singer, Brett C.

2005-01-05

The dynamic behavior of volatile organic compounds (VOCs) in indoor environments depends, in part, on sorptive interactions between VOCs in the gas phase and material surfaces. Since information on the types and quantities of interior material surfaces is not generally available, this pilot-scale study was conducted in occupied residences to develop and demonstrate a method for quantifying surface areas of objects and materials in rooms. Access to 33 rooms in nine residences consisting of bathrooms, bedroom/offices and common areas was solicited from among research group members living in the East San Francisco Bay Area. A systematic approach was implemented formore » measuring rooms and objects from 300 cm{sup 2} and larger. The ventilated air volumes of the rooms were estimated and surface area-to-volume ratios were calculated for objects and materials, each segregated into 20 or more categories. Total surface area-to-volume ratios also were determined for each room. The bathrooms had the highest total surface area-to-volume ratios. Bedrooms generally had higher ratios than common areas consisting of kitchens, living/dining rooms and transitional rooms. Total surface area-to-volume ratios for the 12 bedrooms ranged between 2.3 and 4.7 m{sup 2} m{sup -3}. The importance of individual objects and materials with respect to sorption will depend upon the sorption coefficients for the various VOC/materials combinations. When combined, the highly permeable material categories, which may contribute to significant interactions, had a median ratio of about 0.5 m{sup 2} m{sup -3} for all three types of rooms.« less

One plunge or two?--hand disinfection with alcohol gel.

PubMed

Macdonald, Duncan J M; Mckillop, Elisabeth C A; Trotter, Sylvia; Gray, Alastair J R

2006-04-01

To compare health care workers' hand surface coverage using two different volumes of alcohol gel for hand disinfection. and methods. A total of 84 members of staff in our hospital were studied. Subjects were asked to disinfect their hands with alcohol gel containing a clear fluorescent substance. Performance was assessed by using UV light to identify areas which had been missed, and the total surface area missed was calculated. A total of 42 subjects received 3.5 ml of alcohol gel, and 42 age-, sex-, and job-matched subjects received 1.75 ml of alcohol gel. Significantly less area was missed when hand disinfecting with double the volume of alcohol gel; 1.23 versus 6.35% surface area was missed (P < 0.001). Doubling the volume of alcohol gel used for hand disinfection significantly improves the efficiency of coverage of the hands with alcohol gel. This may result in lower bacterial count on the hands and may reduce the spread of nosocomial infections including that of methicillin-resistant Staphylococcus aureus.

Influence of N2 annealing on TiO2 tubes structure and its photocatalytic activity

NASA Astrophysics Data System (ADS)

Chen, Xiaoxiang; Pan, Zhanchang; Yu, Ke; Xiao, Jun; Wu, Shoukun; Li, Jinghong; Chen, Chun; Lin, Yingsheng; Hu, Guanghui; Xu, Yanbin

2018-02-01

In this work, the TiO2 tubes (TBs) were prepared by solvothermal method. The morphology and phase structure of TiO2 TBs is significantly affected by N2 annealing temperature. XRD was used to characterize the phase structure of the as-prepared samples. The morphology and surface areas were characterized by SEM and N2 adsorption-desorption, which show that the tubes were assembled with about 100-nm nanosheets and small ball particles under 400 and 600 °C N2 annealing; when temperature reached 800 °C, the surface of tubes appeared a lot of collapse and many large holes. In addition, the surface areas of 400 °C TiO2, 600 °C TiO2, and 800 °C TiO2 TBs were significantly affected by N2 annealing. Most importantly, the UV-vis and electrochemical tests demonstrate 600 °C TiO2 TBs exhibit higher absorption intensity and photocurrent; thus, it possess on better photocatalytic activity. Therefore, the photocatalytic performance for TiO2 TBs is significantly co-affected by surface area and mix-phase. [Figure not available: see fulltext.

Surface Soil Preparetion for Leguminous Plants Growing in Degraded Areas by Mining Located in Amazon Forest-Brazil

NASA Astrophysics Data System (ADS)

Irio Ribeiro, Admilson; Hashimoto Fengler, Felipe; Araújo de Medeiros, Gerson; Márcia Longo, Regina; Frederici de Mello, Giovanna; José de Melo, Wanderley

2015-04-01

The revegetation of areas degraded by mining usually requires adequate mobilization of surface soil for the development of the species to be implemented. Unlike the traditional tillage, which has periodicity, the mobilization of degraded areas for revegetation can only occur at the beginning of the recovery stage. In this sense, the process of revegetation has as purpose the establishment of local native vegetation with least possible use of inputs and superficial tillage in order to catalyze the process of natural ecological succession, promoting the reintegration of areas and minimizing the negative impacts of mining activities in environmental. In this context, this work describes part of a study of land reclamation by tin exploitation in the Amazon ecosystem in the National Forest Jamari- Rondonia Brazil. So, studied the influence of surface soil mobilization in pit mine areas and tailings a view to the implementation of legumes. The results show that the surface has areas of mobilizing a significant effect on the growth of leguminous plants, areas for both mining and to tailings and pit mine areas.

An Assessment of Soil Disturbance from Five Harvesting Intensities

Treesearch

John Klepac; Stephen E. Reutebuch; Robert B. Rummer

1999-01-01

Surface soil disturbance was compared among a commercial thinning, group selection, patch cut, 2-age, and clearcut. The thinning, group selection and patch cut units had significantly higher percentages of undisturbed area. The 2-age unit had a significantly higher percentage of area disturbed with litter in place. The clearcut unit had a significantly higher...

Electrodeposition of Highly Porous Pt Nanoparticles Studied by Quantitative 3D Electron Tomography: Influence of Growth Mechanisms and Potential Cycling on the Active Surface Area.

PubMed

Ustarroz, Jon; Geboes, Bart; Vanrompay, Hans; Sentosun, Kadir; Bals, Sara; Breugelmans, Tom; Hubin, Annick

2017-05-17

Nanoporous Pt nanoparticles (NPs) are promising fuel cell catalysts due to their large surface area and increased electrocatalytic activity toward the oxygen reduction reaction (ORR). Herein, we report on the influence of the growth mechanisms on the surface properties of electrodeposited Pt dendritic NPs with large surface areas. The electrochemically active surface was studied by hydrogen underpotential deposition (H UPD) and compared for the first time to high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) quantitative 3D electron tomography of individual nanoparticles. Large nucleation overpotential leads to a large surface coverage of roughened spheroids, which provide a large roughness factor (R f ) but low mass-specific electrochemically active surface area (EASA). Lowering the nucleation overpotential leads to highly porous Pt NPs with pores stretching to the center of the structure. At the expense of smaller R f , the obtained EASA values of these structures are in the range of those of large surface area supported fuel cell catalysts. The active surface area of the Pt dendritic NPs was measured by electron tomography, and it was found that the potential cycling in the H adsorption/desorption and Pt oxidation/reduction region, which is generally performed to determine the EASA, leads to a significant reduction of that surface area due to a partial collapse of their dendritic and porous morphology. Interestingly, the extrapolation of the microscopic tomography results in macroscopic electrochemical parameters indicates that the surface properties measured by H UPD are comparable to the values measured on individual NPs by electron tomography after the degradation caused by the H UPD measurement. These results highlight that the combination of electrochemical and quantitative 3D surface analysis techniques is essential to provide insights into the surface properties, the electrochemical stability, and, hence, the applicability of these materials. Moreover, it indicates that care must be taken with widely used electrochemical methods of surface area determination, especially in the case of large surface area and possibly unstable nanostructures, since the measured surface can be strongly affected by the measurement itself.

Determination of retinal surface area.

PubMed

Nagra, Manbir; Gilmartin, Bernard; Thai, Ngoc Jade; Logan, Nicola S

2017-09-01

Previous attempts at determining retinal surface area and surface area of the whole eye have been based upon mathematical calculations derived from retinal photographs, schematic eyes and retinal biopsies of donor eyes. 3-dimensional (3-D) ocular magnetic resonance imaging (MRI) allows a more direct measurement, it can be used to image the eye in vivo, and there is no risk of tissue shrinkage. The primary purpose of this study is to compare, using T2-weighted 3D MRI, retinal surface areas for superior-temporal (ST), inferior-temporal (IT), superior-nasal (SN) and inferior-nasal (IN) retinal quadrants. An ancillary aim is to examine whether inter-quadrant variations in area are concordant with reported inter-quadrant patterns of susceptibility to retinal breaks associated with posterior vitreous detachment (PVD). Seventy-three adult participants presenting without retinal pathology (mean age 26.25 ± 6.06 years) were scanned using a Siemens 3-Tesla MRI scanner to provide T2-weighted MR images that demarcate fluid-filled internal structures for the whole eye and provide high-contrast delineation of the vitreous-retina interface. Integrated MRI software generated total internal ocular surface area (TSA). The second nodal point was used to demarcate the origin of the peripheral retina in order to calculate total retinal surface area (RSA) and quadrant retinal surface areas (QRSA) for ST, IT, SN, and IN quadrants. Mean spherical error (MSE) was -2.50 ± 4.03D and mean axial length (AL) 24.51 ± 1.57 mm. Mean TSA and RSA for the RE were 2058 ± 189 and 1363 ± 160 mm 2 , respectively. Repeated measures anova for QRSA data indicated a significant difference within-quadrants (P < 0.01) which, contrasted with ST (365 ± 43 mm 2 ), was significant for IT (340 ± 40 mm 2 P < 0.01), SN (337 ± 40 mm 2 P < 0.01) and IN (321 ± 39 mm 2 P < 0.01) quadrants. For all quadrants, QRSA was significantly correlated with AL (P < 0.01) and exhibited equivalent increases in retinal area/mm increase in AL. Although the differences between QRSAs are relatively small, there was evidence of concordance with reported inter-quadrant patterns of susceptibility to retinal breaks associated with PVD. The data allow AL to be converted to QRSAs, which will assist further work on inter-quadrant structural variation. © 2017 Anatomical Society.

Investigating the Impact of Surface Heterogeneity on the Convective Boundary Layer Over Urban Areas Through Coupled Large-Eddy Simulation and Remote Sensing

NASA Technical Reports Server (NTRS)

Dominguez, Anthony; Kleissl, Jan P.; Luvall, Jeffrey C.

2011-01-01

Large-eddy Simulation (LES) was used to study convective boundary layer (CBL) flow through suburban regions with both large and small scale heterogeneities in surface temperature. Constant remotely sensed surface temperatures were applied at the surface boundary at resolutions of 10 m, 90 m, 200 m, and 1 km. Increasing the surface resolution from 1 km to 200 m had the most significant impact on the mean and turbulent flow characteristics as the larger scale heterogeneities became resolved. While previous studies concluded that scales of heterogeneity much smaller than the CBL inversion height have little impact on the CBL characteristics, we found that further increasing the surface resolution (resolving smaller scale heterogeneities) results in an increase in mean surface heat flux, thermal blending height, and potential temperature profile. The results of this study will help to better inform sub-grid parameterization for meso-scale meteorological models. The simulation tool developed through this study (combining LES and high resolution remotely sensed surface conditions) is a significant step towards future studies on the micro-scale meteorology in urban areas.

Cooling effect of rivers on metropolitan Taipei using remote sensing.

PubMed

Chen, Yen-Chang; Tan, Chih-Hung; Wei, Chiang; Su, Zi-Wen

2014-01-23

This study applied remote sensing technology to analyze how rivers in the urban environment affect the surface temperature of their ambient areas. While surface meteorological stations can supply accurate data points in the city, remote sensing can provide such data in a two-dimensional (2-D) manner. The goal of this paper is to apply the remote sensing technique to further our understanding of the relationship between the surface temperature and rivers in urban areas. The 2-D surface temperature data was retrieved from Landsat-7 thermal infrared images, while data collected by Formosat-2 was used to categorize the land uses in the urban area. The land surface temperature distribution is simulated by a sigmoid function with nonlinear regression analysis. Combining the aforementioned data, the range of effect on the surface temperature from rivers can be derived. With the remote sensing data collected for the Taipei Metropolitan area, factors affecting the surface temperature were explored. It indicated that the effect on the developed area was less significant than on the ambient nature zone; moreover, the size of the buffer zone between the river and city, such as the wetlands or flood plain, was found to correlate with the affected distance of the river surface temperature.

Cooling Effect of Rivers on Metropolitan Taipei Using Remote Sensing

PubMed Central

Chen, Yen-Chang; Tan, Chih-Hung; Wei, Chiang; Su, Zi-Wen

2014-01-01

This study applied remote sensing technology to analyze how rivers in the urban environment affect the surface temperature of their ambient areas. While surface meteorological stations can supply accurate data points in the city, remote sensing can provide such data in a two-dimensional (2-D) manner. The goal of this paper is to apply the remote sensing technique to further our understanding of the relationship between the surface temperature and rivers in urban areas. The 2-D surface temperature data was retrieved from Landsat-7 thermal infrared images, while data collected by Formosat-2 was used to categorize the land uses in the urban area. The land surface temperature distribution is simulated by a sigmoid function with nonlinear regression analysis. Combining the aforementioned data, the range of effect on the surface temperature from rivers can be derived. With the remote sensing data collected for the Taipei Metropolitan area, factors affecting the surface temperature were explored. It indicated that the effect on the developed area was less significant than on the ambient nature zone; moreover, the size of the buffer zone between the river and city, such as the wetlands or flood plain, was found to correlate with the affected distance of the river surface temperature. PMID:24464232

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.

Location of unaccessible implant surface areas during debridement in simulated peri-implantitis therapy.

PubMed

Steiger-Ronay, Valerie; Merlini, Andrea; Wiedemeier, Daniel B; Schmidlin, Patrick R; Attin, Thomas; Sahrmann, Philipp

2017-11-28

An in vitro model for peri-implantitis treatment was used to identify areas that are clinically difficult to clean by analyzing the pattern of residual stain after debridement with commonly employed instruments. Original data from two previous publications, which simulated surgical (SA) and non-surgical (NSA) implant debridement on two different implant systems respectively, were reanalyzed regarding the localization pattern of residual stains after instrumentation. Two blinded examiners evaluated standardized photographs of 360 initially ink-stained dental implants, which were cleaned at variable defect angulations (30, 60, or 90°), using different instrument types (Gracey curette, ultrasonic scaler or air powder abrasive device) and treatment approaches (SA or NSA). Predefined implant surface areas were graded for residual stain using scores ranging from one (stain-covered) to six (clean). Score differences between respective implant areas were tested for significance by pairwise comparisons using Wilcoxon-rank-sum-tests with a significance level α = 5%. Best scores were found at the machined surface areas (SA: 5.58 ± 0.43, NSA: 4.76 ± 1.09), followed by the tips of the threads (SA: 4.29 ± 0.44, NSA: 4.43 ± 0.61), and areas between threads (SA: 3.79 ± 0.89, NSA: 2.42 ± 1.11). Apically facing threads were most difficult to clean (SA: 1.70 ± 0.92, NSA: 2.42 ± 1.11). Here, air powder abrasives provided the best results. Machined surfaces at the implant shoulder were well accessible and showed least amounts of residual stain. Apically facing thread surfaces constituted the area with most residual stain regardless of treatment approach.

The effect of low force chiropractic adjustments on body surface electromagnetic field.

PubMed

Zhang, John; Snyder, Brian J; Vernor, Lori

2004-03-01

The purpose of this study was to investigate the body surface electromagnetic field (EMF) changes using a sensitive magnetometer before and after a specific Toftness chiropractic adjustment in asymptomatic human subjects. Forty-four subjects were randomly assigned into control (20 subjects) and experimental groups (24 subjects) in a pre and post-test design. The Triaxial Fluxgate Magnetometer FGM-5DTAA (Walker Scientific, Worcester, Massachusetts) with five digit display and resolution of 1 nanotesla (nT) was used for EMF detection. The EMF in the research room and on the adjustment table was monitored and recorded. The subjects' body surface (cervical, thoracic, lumbar and sacral areas) EMF was determined in the prone position before and after the chiropractic adjustment. A low force Toftness chiropractic adjustment was applied to the cervical, thoracic, lumbar and sacral areas as determined by the practitioner. The EMF in the research room was recorded as 41611 nT at the Z axis (earth field), 13761 nT at the X axis and 7438 nT at the Y axis. The EMF on the adjusting table changed minimally during the 15 minute observation period. The EMF on the subjects' body surface decreased at 4 spinal locations after chiropractic adjustment. The EMF (mean +/- SD in nT) decreased significantly at the cervical region from 42449 +/- 907 to 41643 +/- 1165 (p < 0.01) and at the sacral regions from 43206 +/- 760 to 42713 +/- 552 (p < 0.01). The EMF at the lumbar and thoracic regions decreased but did not reach a statistically significant level. No significant changes of the body surface EMF were found in the control group. A low force Toftness chiropractic adjustment in the cervical and sacral areas resulted in a significant reduction of the cervical and sacral surface EMF. No significant body surface EMF changes were observed in the lumbar and thoracic regions. The mechanisms of the EMF reduction after chiropractic adjustment are not known.

The effect of low force chiropractic adjustments on body surface electromagnetic field

PubMed Central

Zhang, John; Snyder, Brian J; Vernor, Lori

2004-01-01

Objective The purpose of this study was to investigate the body surface electromagnetic field (EMF) changes using a sensitive magnetometer before and after a specific Toftness chiropractic adjustment in asymptomatic human subjects. Method Forty-four subjects were randomly assigned into control (20 subjects) and experimental groups (24 subjects) in a pre and post-test design. The Triaxial Fluxgate Magnetometer FGM-5DTAA (Walker Scientific, Worcester, Massachusetts) with five digit display and resolution of 1 nanotesla (nT) was used for EMF detection. The EMF in the research room and on the adjustment table was monitored and recorded. The subjects’ body surface (cervical, thoracic, lumbar and sacral areas) EMF was determined in the prone position before and after the chiropractic adjustment. A low force Toftness chiropractic adjustment was applied to the cervical, thoracic, lumbar and sacral areas as determined by the practitioner. Results The EMF in the research room was recorded as 41611 nT at the Z axis (earth field), 13761 nT at the X axis and 7438 nT at the Y axis. The EMF on the adjusting table changed minimally during the 15 minute observation period. The EMF on the subjects’ body surface decreased at 4 spinal locations after chiropractic adjustment. The EMF (mean ± SD in nT) decreased significantly at the cervical region from 42449 ± 907 to 41643 ± 1165 (p < 0.01) and at the sacral regions from 43206 ± 760 to 42713 ± 552 (p < 0.01). The EMF at the lumbar and thoracic regions decreased but did not reach a statistically significant level. No significant changes of the body surface EMF were found in the control group. Conclusion A low force Toftness chiropractic adjustment in the cervical and sacral areas resulted in a significant reduction of the cervical and sacral surface EMF. No significant body surface EMF changes were observed in the lumbar and thoracic regions. The mechanisms of the EMF reduction after chiropractic adjustment are not known. PMID:17549217

Development of large-surface Nafion-metal composite actuator and its electrochemical characterization

NASA Astrophysics Data System (ADS)

Noh, Taegeun; Tak, Yong Suk; Nam, Jaedo; Jeon, Jaewook; Kim, Hunmo; Choi, Hyoukryeol; Bae, Sang Sik

2001-07-01

Behaviors of nafion-based actuators are significantly affected by interfacial area between electrode and polymer electrolyte. Replication method was utilized to manufacture a large surface-area composite actuator. Etched aluminum foil was used as a template for replication using liquid nafion solution. Measurement of double layer charging and scanning electron microscopy indicated that interfacial area was greatly increased by replication method. Higher surface area induced a better bending performance of ionic polymer metal composite (IPMC). In parallel, the effect of cations on IPMC was interpreted with constant current experiment, linear sweep voltammetry and electrochemical impedance spectroscopy. For univalent cations, ion size is the most influencing parameter on ionic mobility inside membrane. However, ion-ion interaction affects an ionic mobility for divalent cations.

Concentrations of asbestos fibers and metals in drinking water caused by natural crocidolite asbestos in the soil from a rural area.

PubMed

Wei, Binggan; Ye, Bingxiong; Yu, Jiangping; Jia, Xianjie; Zhang, Biao; Zhang, Xiuwu; Lu, Rongan; Dong, Tingrong; Yang, Linsheng

2013-04-01

Asbestos fibers and metals in drinking water are of significant importance to the field of asbestos toxicology. However, little is known about asbestos fibers and metals in drinking water caused by naturally occurring asbestos. Therefore, concentrations of asbestos fibers and metals in well and surface waters from asbestos and control areas were measured by scanning electron microscopy (SEM), inductively coupled plasma (ICP) optical emission spectrometer, and ICP-mass spectrometry in this study. The results indicated that the mean concentration of asbestos fibers was 42.34 millions of fibers per liter by SEM, which was much higher than the permission exposure level. The main compositions of both asbestos fibers in crocidolite mineral and in drinking water were Na, Mg, Fe, and Si based on energy dispersive X-ray analysis. This revealed that the drinking water has been contaminated by asbestos fibers from crocidolite mineral in soil and rock. Except for Cr, Pb, Zn, and Mn, the mean concentrations of Ni, Na, Mg, K, Fe, Ca, and SiO2 were much higher in both surface water and well waters from the asbestos area than in well water from the control area. The results of principal component and cluster analyses indicated that the metals in surface and well waters from the asbestos area were significantly influenced by crocidolite mineral in soil and rock. In the asbestos area, the mean concentrations of asbestos fibers and Ni, Na, Mg, K, Fe, Ca, and SiO2 were higher in surface and well waters, indicating that asbestos fibers and the metals were significantly influenced by crocidolite in soil and rock.

The use of fractography to supplement analysis of bone mechanical properties in different strains of mice.

PubMed

Wise, L M; Wang, Z; Grynpas, M D

2007-10-01

Fractography has not been fully developed as a useful technique in assessing failure mechanisms of bone. While fracture surfaces of osteonal bone have been explored, this may not apply to conventional mechanical testing of mouse bone. Thus, the focus of this work was to develop and evaluate the efficacy of a fractography protocol for use in supplementing the interpretation of failure mechanisms in mouse bone. Micro-computed tomography and three-point bending were performed on femora of two groups of 6-month-old mice (C57BL/6 and a mixed strain background of 129SV/C57BL6). SEM images of fracture surfaces were collected, and areas of "tension", "compression" and "transition" were identified. Percent areas of roughness were identified and estimated within areas of "tension" and "compression" and subsequently compared to surface roughness measurements generated from an optical profiler. Porosity parameters were determined on the tensile side. Linear regression analysis was performed to evaluate correlations between certain parameters. Results show that 129 mice exhibit significantly increased bone mineral density (BMD), number of "large" pores, failure strength, elastic modulus and energy to failure compared to B6 mice (p<0.001). Both 129 and B6 mice exhibit significantly (p<0.01) more percent areas of tension (49+/-1%, 42+/-2%; respectively) compared to compression (26+/-2%, 31+/-1%; respectively). In terms of "roughness", B6 mice exhibit significantly less "rough" areas (30+/-4%) compared to "smooth" areas (70+/-4%) on the tensile side only (p<0.001). Qualitatively, 129 mice demonstrate more evidence of bone toughening through fiber bridging and loosely connected fiber bundles. The number of large pores is positively correlated with failure strength (p=0.004), elastic modulus (p=0.002) and energy to failure (p=0.041). Percent area of tensile surfaces is positively correlated with failure strength (p<0.001), elastic modulus (p=0.016) and BMD (p=0.037). Percent area of rough compressive surfaces is positively correlated with energy to failure (p=0.039). Evaluation of fracture surfaces has helped to explain why 129 mice have increased mechanical properties compared to B6 mice, namely via toughening mechanisms on the compressive side of failure. Several correlations exist between fractography parameters and mechanical behavior, supporting the utility of fractography with skeletal mouse models.

Comparative evaluation of root canal preparations of maxillary first molars with self-adjusting file, reciproc single file, and revo-s rotary file: A micro-computed tomography study.

PubMed

Ahmetoglu, Fuat; Keles, Ali; Simsek, Neslihan; Ocak, M Sinan; Yologlu, Saim

2015-01-01

This study was aimed to use micro-computed tomography (μ-CT) to evaluate the canal shaping properties of three nickel-titanium instruments, Self-Adjusting File (SAF), Reciproc, and Revo-S rotary file, in maxillary first molars. Thirty maxillary molars were scanned preoperatively by using micro-computed tomography (μ-CT) scans at 13,68 μm resolution. The teeth were randomly assigned to three groups (n = 10). The root canals were shaped with SAF, Reciproc, and Revo-S, respectively. The shaped root canals were rescanned. Changes in canal volumes and surface areas were compared with preoperative values. The data were analyzed using Kruskal-Wallis and Conover's post hoc tests, with p < .05 denoting a statistically significant difference. Preoperatively canal volumes and surface area were statistically similar among the three groups (p > .05). There were statistically significant differences in all measures comparing preoperative and postoperative canal models (p = 0.0001). These differences occurred after instrumentation among the three experimental groups showed no statistically significant difference for volume (p > .05). Surface area showed the similar activity in buccal canals in each of the three techniques whereas no statistically significant difference was detected among surface area, the SAF, and the Revo-S in the palatal (P) canal. Each of three shaping system showed the similar volume activity in all canals, but SAF and Revo-S provided more effectively root planning in comparison with Reciproc in P canal. © Wiley Periodicals, Inc.

Distinctive Features of Surface Winds over Indian Ocean Between Strong and Weak Indian Summer Monsoons: Implications With Respect To Regional Rainfall Change in India

NASA Astrophysics Data System (ADS)

Zheng, Y.; Bourassa, M. A.; Ali, M. M.

2017-12-01

This observational study focuses on characterizing the surface winds in the Arabian Sea (AS), the Bay of Bengal (BoB), and the southern Indian Ocean (SIO) with special reference to the strong and weak Indian summer monsoon rainfall (ISMR) using the latest daily gridded rainfall dataset provided by the Indian Meteorological Department (IMD) and the Cross-Calibrated Multi-Platform (CCMP) gridded wind product version 2.0 produced by Remote Sensing System (RSS) over the overlapped period 1991-2014. The potential links between surface winds and Indian regional rainfall are also examined. Results indicate that the surface wind speeds in AS and BoB during June-August are almost similar during strong ISMRs and weak ISMRs, whereas significant discrepancies are observed during September. By contrast, the surface wind speeds in SIO during June-August are found to be significantly different between strong and weak ISMRs, where they are similar during September. The significant differences in monthly mean surface wind convergence between strong and weak ISMRs are not coherent in space in the three regions. However, the probability density function (PDF) distributions of daily mean area-averaged values are distinctive between strong and weak ISMRs in the three regions. The correlation analysis indicates the area-averaged surface wind speeds in AS and the area-averaged wind convergence in BoB are highly correlated with regional rainfall for both strong and weak ISMRs. The wind convergence in BoB during strong ISMRs is relatively better correlated with regional rainfall than during weak ISMRs. The surface winds in SIO do not greatly affect Indian rainfall in short timescales, however, they will ultimately affect the strength of monsoon circulation by modulating Indian Ocean Dipole (IOD) mode via atmosphere-ocean interactions.

Ion Velocity Distribution in a Low-Power Cylindrical Hall Thruster

DTIC Science & Technology

2010-07-01

profile inside a CHT – the magnetic field lines are believed to form equipotential surfaces , creating an electric field that has a significant axial...centerline of the channel. The resulting equipotential surfaces provide an electric field profile with a significant outward pointing radial component...pole and creating a region of the channel with a low surface -to-volume area (a cylindrical region), the CHT as developed by Princeton University reduces

A longitudinal study: changes in cortical thickness and surface area during pubertal maturation.

PubMed

Herting, Megan M; Gautam, Prapti; Spielberg, Jeffrey M; Dahl, Ronald E; Sowell, Elizabeth R

2015-01-01

Sex hormones have been shown to contribute to the organization and function of the brain during puberty and adolescence. Moreover, it has been suggested that distinct hormone changes in girls versus boys may contribute to the emergence of sex differences in internalizing and externalizing behavior during adolescence. In the current longitudinal study, the influence of within-subject changes in puberty (physical and hormonal) on cortical thickness and surface area was examined across a 2-year span, while controlling for age. Greater increases in Tanner Stage predicted less superior frontal thinning and decreases in precuneus surface area in both sexes. Significant Tanner Stage and sex interactions were also seen, with less right superior temporal thinning in girls but not boys, as well as greater decreases in the right bank of the superior temporal sulcus surface area in boys compared to girls. In addition, within-subject changes in testosterone over the 2-year follow-up period were found to relate to decreases in middle superior frontal surface area in boys, but increases in surface area in girls. Lastly, larger increases in estradiol in girls predicted greater middle temporal lobe thinning. These results show that within-subject physical and hormonal markers of puberty relate to region and sex-specific changes in cortical development across adolescence.

[Effects of tillage practices on root spatial distribution and yield of spring wheat and pea in the dry land farming areas of central Gansu, China].

PubMed

Zhang, Ming Jun; Li, Ling Ling; Xie, Jun Hong; Peng, Zheng Kai; Ren, Jin Hu

2017-12-01

A field experiment was conducted to explore the mechanism of cultivation measures in affecting crop yield by investigating root distribution in spring wheat-pea rotation based on a long-term conservation tillage practices in a farming region of Gansu. The results showed that with the develo-pment of growth period, the total root length, root surface area of spring wheat and pea showed a consistent trend of increase after initial decrease and reached the maximum at flowering stage. Higher root distribution was found in the 0-10 cm soil layer at seedling and 10-30 cm soil layer at flowering and maturity stages in spring wheat, while in the field pea, higher root distribution was found in the 0-10 cm soil layer at seedling and maturity, and in the 10-30 cm soil layer at flowering stages. No tillage with straw mulching and plastic mulching increased the root length and root surface area. Compared with conventional tillage in spring wheat and field pea, root length increased by 35.9% to 92.6%, and root surface area increased by 43.2% to 162.4%, respectively. No tillage with straw mulching and plastic mulching optimized spring wheat and pea root system distribution, compared with conventional tillage, increased spring wheat and field pea root length and root surface area ratio at 0-10 cm depths at the seedling stage, the root distribution at deeper depths increased significantly at flowering and maturity stages, and no tillage with straw mulching increased root length and root surface area ratio by 3.3% and 9.7% respectively, in 30-80 cm soil layer at the flowering stage. The total root length, root surface area and yield had significantly positive correlation for spring wheat in each growth period, and the total root length and pea yield also had significant positive correlation. No tillage with straw mulching and plastic mulching boosted yield of spring wheat and pea by 23.4%-38.7% compared with the conventional tillage, and the water use efficiency was increased by 13.7%-28.5%. It was concluded that no-till farming and straw mulching (plastic) could increase crop root length and root surface area, optimize the spatial distribution of roots in the soil, enhance crop root layer absorption ability, so as to improve crop yield and water utilization.

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

Biological and Chemical Significance of Surface Microlayers in Aquatic Ecosystems

ERIC Educational Resources Information Center

Parker, B.; Barsom, G.

1970-01-01

Reviews methods of study, chemical composition, physical properties and ecology of surface microlayers in marine and fresh water habitats. Relates to problems of air and water pollution. Suggests areas for further research. (EB)

CHAPTER 17: STORMWATER

EPA Science Inventory

The process of urbanization causes significant changes to the hydrologic regime of catchments through increased impervious areas (roads, roofs, etc) and alterations to the natural drainage network. Some examples of urbanization processes include: increasing surface area of road ...

Single-step uncalcined N-TiO2 synthesis, characterizations and its applications on alachlor photocatalytic degradations

NASA Astrophysics Data System (ADS)

Suwannaruang, Totsaporn; Wantala, Kitirote

2016-09-01

The aims of this research were to synthesize nitrogen doped TiO2 (N-TiO2) photocatalysts produced by hydrothermal technique and to test the degradation performance of alachlor by photocatalytic process under UV irradiations in the effect of aging temperature and time in the preparation process. The characterizations of synthesized TiO2 such as specific surface area, particle size, phase structure and elements were analyzed by using the Brunauer-Emmett-Teller (BET) technique, Transmission Electron Microscopy (TEM), X-ray Diffractometer (XRD) and Energy Dispersive X-ray spectrometer (EDX), respectively. The Central Composite Design (CCD) was used to design the experiment to determine the optimal condition, main effects and their interactions by using specific surface area, percent alachlor removal and observed first-order rate constant as responses. The kinetic reactions of alachlor degradation were explained by using Langmuir-Hinshelwood expression to confirm the reaction took place on the surface of photocatalyst. The results showed that the effect of aging temperatures was significant on surface area, whereas aging time was insignificant. Additionally, the square term of aging temperature and interaction term were shown significant on the specific surface area as well. The highest specific surface area from response surface at aging temperature between 150-175 °C and aging time between 6-13 h was found in a range of 100-106 m2/g. The average particle size of TiO2 was similar to crystallite size. Therefore, it can be concluded that one particle has only one crystal. The element analysis has shown 10% of nitrogen in TiO2 structure that the energy band-gap about 2.95 eV was found. Although, the effects of aging temperature and time on percent alachlor removal and observed first-order rate constants were insignificant, both terms were significant in term of the square for alachlor photocatalytic degradation. The optimal condition of both responses was achieved at an aging temperature of 145 °C and aging time of 12 h.

Surface Area of Patellar Facets: Inferential Statistics in the Iraqi Population

PubMed Central

Al-Zamili, Zaid; Omar, Rawan

2017-01-01

Background. The patella is the largest sesamoid bone in the body; its three-dimensional complexity necessitates biomechanical perfection. Numerous pathologies occur at the patellofemoral unit which may end in degenerative changes. This study aims to test the presence of statistical correlation between the surface areas of patellar facets and other patellar morphometric parameters. Materials and Methods. Forty dry human patellae were studied. The morphometry of each patella was measured using a digital Vernier Caliper, electronic balance, and image analyses software known as ImageJ. The patellar facetal surface area was correlated with patellar weight, height, width, and thickness. Results. Inferential statistics proved the existence of linear correlation of total facetal surface area and patellar weight, height, width, and thickness. The correlation was strongest for surface area versus patellar weight. The lateral facetal area was found persistently larger than the medial facetal area, the p value was found to be <0.001 (one-tailed t-test) for right patellae, and another significant p value of < 0.001 (one-tailed t-test) was found for left patellae. Conclusion. These data are vital for the restoration of the normal biomechanics of the patellofemoral unit; these are to be consulted during knee surgeries and implant designs and can be of an indispensable anthropometric, interethnic, and biometric value. PMID:28348891

Aquatic adaptations in the nose of carnivorans: evidence from the turbinates

PubMed Central

Van Valkenburgh, Blaire; Curtis, Abigail; Samuels, Joshua X; Bird, Deborah; Fulkerson, Brian; Meachen-Samuels, Julie; Slater, Graham J

2011-01-01

Inside the mammalian nose lies a labyrinth of bony plates covered in epithelium collectively known as turbinates. Respiratory turbinates lie anteriorly and aid in heat and water conservation, while more posterior olfactory turbinates function in olfaction. Previous observations on a few carnivorans revealed that aquatic species have relatively large, complex respiratory turbinates and greatly reduced olfactory turbinates compared with terrestrial species. Body heat is lost more quickly in water than air and increased respiratory surface area likely evolved to minimize heat loss. At the same time, olfactory surface area probably diminished due to a decreased reliance on olfaction when foraging under water. To explore how widespread these adaptations are, we documented scaling of respiratory and olfactory turbinate surface area with body size in a variety of terrestrial, freshwater, and marine carnivorans, including pinnipeds, mustelids, ursids, and procyonids. Surface areas were estimated from high-resolution CT scans of dry skulls, a novel approach that enabled a greater sampling of taxa than is practical with fresh heads. Total turbinate, respiratory, and olfactory surface areas correlate well with body size (r2 ≥ 0.7), and are relatively smaller in larger species. Relative to body mass or skull length, aquatic species have significantly less olfactory surface area than terrestrial species. Furthermore, the ratio of olfactory to respiratory surface area is associated with habitat. Using phylogenetic comparative methods, we found strong support for convergence on 1 : 3 proportions in aquatic taxa and near the inverse in terrestrial taxa, indicating that aquatic mustelids and pinnipeds independently acquired similar proportions of olfactory to respiratory turbinates. Constraints on turbinate surface area in the nasal chamber may result in a trade-off between respiratory and olfactory function in aquatic mammals. PMID:21198587

Impact of pore size on the sorption of uranyl under seawater conditions

DOE PAGES

Mayes, Richard T.; Gorka, Joanna; Dai, Sheng

2016-04-05

The extraction of uranium from seawater has received significant interest recently, because of the possibility of a near-limitless supply of uranium to fuel the nuclear power industry. While sorbent development has focused primarily on polymeric sorbents, nanomaterials represent a new area that has the potential to surpass the current polymeric sorbents, because of the high surface areas that are possible. Mesoporous carbon materials are a stable, high-surface-area material capable of extracting various chemical species from a variety of environments. Herein, we report the use of a dual templating process to understand the effect of pore size on the adsorption ofmore » uranyl ions from a uranyl brine consisting of seawater-relevant sodium, chloride, and bicarbonate ions. It was found that pore size played a more significant role in the effective use of the grafted polymer, leading to higher uranium capacities than the surface area. Furthermore, the pore size must be tailored to meet the demands of the extraction medium and analyte metal to achieve efficacy as an adsorbent.« less

Kinetics of gibbsite dissolution under low ionic strength conditions

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

Ganor, J.; Mogollon, J.L.; Lasaga, A.C.

1999-06-01

Experiments measuring synthetic gibbsite dissolution rates were carried out using both a stirred-flow-through reactor and a column reactor at 25 C, and pH range of 2.5--4.1. All experiments were conducted under far from equilibrium conditions ({Delta}G < {minus}1.1 kcal/mole). The experiments were performed with perchloric acid under relatively low (and variable) ionic strength conditions. An excellent agreement was found between the results of the well-mixed flow-through experiments and those of the (nonmixed) column experiments. This agreement shows that the gibbsite dissolution rate is independent of the stirring rate and therefore supports the conclusion of Bloom and Erich (1987) that gibbsitemore » dissolution reaction is surface controlled and not diffusion controlled. The Brunauer-Emmett-Teller (BET) surface area of the gibbsite increased during the flow-through experiments, while in the column experiments no significant change in surface area was observed. The significant differences in the BET surface area between the column experiments and the flow-through experiments, and the excellent agreement between the rates obtained by both methods, enable the authors to justify the substitution of the BET surface area for the reactive surface area. The dissolution rate of gibbsite varied as a function of the perchloric acid concentration. The authors interpret the gibbsite dissolution rate as a result of a combined effect of proton catalysis and perchlorate inhibition. Following the theoretical study of Ganor and Lasaga (1998) they propose specific reaction mechanisms for the gibbsite dissolution in the presence of perchloric acid. The mathematical predictions of two of these reaction mechanisms adequately describe the experimental data.« less

Contributions to Crustal Mechanics on Europa from Subterranean Ocean Vibrations

NASA Astrophysics Data System (ADS)

Hayes, Robert

2016-03-01

The recent discovery of subduction zones on Europa demonstrated a significant step forward in understanding the moon's surface mechanics. This work promotes the additional consideration that the surface mechanics have contributions from small relative pressure differentials in the subsurface ocean that create cracks in the surface which are then filled, sealed and healed. Crack formation can be small, as interior pressure can relatively easily breach the surface crust, generating cracks followed by common fracture formation backfilled with frozen liquid. This process will slowly increase the overall surface area of the moon with each sealed crack and fracture increasing the total surface area. This creeping growth of surface area monotonically decreases subsurface pressure which can eventually catastrophically subduct large areas of surface and so is consistent with current knowledge of observational topology on Europa. This tendency is attributed to a relatively lower energy threshold to crack the surface from interior overpressures, but a higher energy threshold to crush the spherical surface due to subsurface underpressures. Proposed mechanisms for pressure differentials include tidal forces whose Fourier components build up the resonant oscillatory modes of the subsurface ocean creating periodic under and overpressure events below the crust. This mechanism provides a means to continually reform the surface of the moon over short geological time scales. This work supported in part by federal Grant NRC-HQ-84-14-G-0059.

Temporal and spatial changes of land use and landscape in a coal mining area in Xilingol grassland

NASA Astrophysics Data System (ADS)

Guan, Chunzhu; Zhang, Baolin; Li, Jiannan; Zhao, Junling

2017-01-01

Coal mining, particularly surface mining, inevitably disturbs land. According to Landsat images acquired over Xilingol grassland in 2005, 2009 and 2015, land uses were divided into seven classes, i. e., open stope, stripping area, waste-dump area, mine industrial area, farmland, urban area and the original landscape (grassland), using supervised classification and human-computer interactive interpretation. The overall classification accuracies were 97.72 %, 98.43 % and 96.73 %, respectively; the Kappa coefficients were 0.95, 0.97 and 0.95, respectively. Analysis on LUCC (Land Use and Cover Change) showed that surface coal mining disturbed grassland ecosystem: grassland decreased by 8661.15 hm2 in 2005-2015. The area and proportion of mining operation areas (open stope, stripping area, waste-dump area, mine industrial field) increased, but those of grassland decreased continuously. Transfer matrix of land use changes showed that waste-dump had the largest impacts in mining disturbance, and that effective reclamation of waste-dump areas would mitigate eco-environment destruction, as would be of great significance to protect fragile grassland eco-system. Six landscape index showed that landscape fragmentation increased, and the influences of human activity on landscape was mainly reflected in the expansion of mining area and urban area. Remote sensing monitoring of coal surface mining in grassland would accurately demonstrate the dynamics and trend of LUCC, providing scientific supports for ecological reconstruction in surface mining area.

Process for forming a porous silicon member in a crystalline silicon member

DOEpatents

Northrup, M. Allen; Yu, Conrad M.; Raley, Norman F.

1999-01-01

Fabrication and use of porous silicon structures to increase surface area of heated reaction chambers, electrophoresis devices, and thermopneumatic sensor-actuators, chemical preconcentrates, and filtering or control flow devices. In particular, such high surface area or specific pore size porous silicon structures will be useful in significantly augmenting the adsorption, vaporization, desorption, condensation and flow of liquids and gasses in applications that use such processes on a miniature scale. Examples that will benefit from a high surface area, porous silicon structure include sample preconcentrators that are designed to adsorb and subsequently desorb specific chemical species from a sample background; chemical reaction chambers with enhanced surface reaction rates; and sensor-actuator chamber devices with increased pressure for thermopneumatic actuation of integrated membranes. Examples that benefit from specific pore sized porous silicon are chemical/biological filters and thermally-activated flow devices with active or adjacent surfaces such as electrodes or heaters.

Full area covered 3D profile measurement of special-shaped optics based on a new prototype non-contact profiler

NASA Astrophysics Data System (ADS)

Du, Hui-Lin; Zhou, Zhao-Zhong; Sun, Ze-Qing; Ju, Bing-Feng; Xu, Shaoning; Sun, Anyu

2017-06-01

A new prototype non-contact profiler based on surface tracking has been specially developed. Surface tracking is carried out by a specially designed dual stage probe system with the aid of a four-Degree Of Freedom high-precision motion platform. The dual stage probe system keeps a short-range optical probe constantly tracking the surface by a self-developed voice coil motor servo, by which a wide measuring range of up to 10 mm is realized. The system performance evaluation including resolution, repeatability, and scanning speed proved the good capability of the new prototype non-contact profiler. To realize a full area covered 3D profile measurement of special-shaped optics within one scanning procedure, a signal intensity monitor integrated in the surface tracking controller is specially developed. In the experiment, a snip-single-corner-rectangular-shaped freeform surface was successfully measured over full area by the new non-contact profiler. This work provides an effective solution for 3D profile measurement of special-shaped optical surfaces over full reflecting area. Experimental results demonstrate that the proposed measuring system is of great significance in quality evaluation of optical surfaces.

Full area covered 3D profile measurement of special-shaped optics based on a new prototype non-contact profiler.

PubMed

Du, Hui-Lin; Zhou, Zhao-Zhong; Sun, Ze-Qing; Ju, Bing-Feng; Xu, Shaoning; Sun, Anyu

2017-06-01

A new prototype non-contact profiler based on surface tracking has been specially developed. Surface tracking is carried out by a specially designed dual stage probe system with the aid of a four-Degree Of Freedom high-precision motion platform. The dual stage probe system keeps a short-range optical probe constantly tracking the surface by a self-developed voice coil motor servo, by which a wide measuring range of up to 10 mm is realized. The system performance evaluation including resolution, repeatability, and scanning speed proved the good capability of the new prototype non-contact profiler. To realize a full area covered 3D profile measurement of special-shaped optics within one scanning procedure, a signal intensity monitor integrated in the surface tracking controller is specially developed. In the experiment, a snip-single-corner-rectangular-shaped freeform surface was successfully measured over full area by the new non-contact profiler. This work provides an effective solution for 3D profile measurement of special-shaped optical surfaces over full reflecting area. Experimental results demonstrate that the proposed measuring system is of great significance in quality evaluation of optical surfaces.

Morphometric and ultrastructural comparison of the olfactory system in elasmobranchs: the significance of structure-function relationships based on phylogeny and ecology.

PubMed

Schluessel, Vera; Bennett, Michael B; Bleckmann, Horst; Blomberg, Simon; Collin, Shaun P

2008-11-01

This study investigated the relationship between olfactory morphology, habitat occupancy, and lifestyle in 21 elasmobranch species in a phylogenetic context. Four measures of olfactory capability, that is, the number of olfactory lamellae, the surface area of the olfactory epithelium, the mass of the olfactory bulb, and the mass of the olfactory rosette were compared between individual species and groups, comprised of species with similar habitat and/or lifestyle. Statistical analyses using generalized least squares phylogenetic regression revealed that bentho-pelagic sharks and rays possess significantly more olfactory lamellae and larger sensory epithelial surface areas than benthic species. There was no significant correlation between either olfactory bulb or rosette mass and habitat type. There was also no significant difference between the number of lamellae or the size of the sensory surface area in groups comprised of species with similar diets, that is, groups preying predominantly on crustaceans, cephalopods, echinoderms, polychaetes, molluscs, or teleosts. However, some groups had significantly larger olfactory bulb or rosette masses than others. There was little evidence to support a correlation between phylogeny and morphology, indicating that differences in olfactory capabilities are the result of functional rather than phylogenetic adaptations. All olfactory epithelia exhibited microvilli and cilia, with microvilli in both nonsensory and sensory areas, and cilia only in sensory areas. Cilia over the sensory epithelia originated from supporting cells. In contrast to teleosts, which possess ciliated and microvillous olfactory receptor types, no ciliated olfactory receptor cells were observed. This is the first comprehensive study comparing olfactory morphology to several aspects of elasmobranch ecology in a phylogenetic context.

Urban Soil: Assessing Ground Cover Impact on Surface Temperature and Thermal Comfort.

PubMed

Brandani, Giada; Napoli, Marco; Massetti, Luciano; Petralli, Martina; Orlandini, Simone

2016-01-01

The urban population growth, together with the contemporary deindustrialization of metropolitan areas, has resulted in a large amount of available land with new possible uses. It is well known that urban green areas provide several benefits in the surrounding environment, such as the improvement of thermal comfort conditions for the population during summer heat waves. The purpose of this study is to provide useful information on thermal regimes of urban soils to urban planners to be used during an urban transformation to mitigate surface temperatures and improve human thermal comfort. Field measurements of solar radiation, surface temperature (), air temperature (), relative humidity, and wind speed were collected on four types of urban soils and pavements in the city of Florence during summer 2014. Analysis of days under calm, clear-sky condition is reported. During daytime, sun-to-shadow differences for , apparent temperature index (ATI), and were significantly positive for all surfaces. Conversely, during nighttime, differences among all surfaces were significantly negative, whereas ATI showed significantly positive differences. Moreover, was significantly negative for grass and gravel. Relative to the shaded surfaces, was higher on white gravel and grass than gray sandstone and asphalt during nighttime, whereas gray sandstone was always the warmest surface during daytime. Conversely, no differences were found during nighttime for ATI and measured over surfaces that were exposed to sun during the day, whereas showed higher values on gravel than grass and asphalt during nighttime. An exposed surface warms less if its albedo is high, leading to a significant reduction of during daytime. These results underline the importance of considering the effects of surface characteristics on surface temperature and thermal comfort. This would be fundamental for addressing urban environment issues toward the heat island mitigation considering also the impact of urban renovation on microclimate. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The human first carpometacarpal joint: osteoarthritic degeneration and 3-dimensional modeling.

PubMed

Kovler, Maksim; Lundon, Katie; McKee, Nancy; Agur, Anne

2004-01-01

The purpose of this study was to gain insight into potential mechanical factors contributing to osteoarthritis of the human first carpometacarpal joint (CMC). This was accomplished by creating three-dimensional (3-D) computer models of the articular surfaces of CMC joints of older humans and by determining their locus of cartilage degeneration. The research questions of this study were: 1) What is the articular wear pattern of cartilage degeneration in CMC osteoarthritis?, (2) Are there significant topographic differences in joint area and contour between the joints of males and females?, and 3) Are there measurable bony joint recesses consistently found within the joint? The articular surfaces of 25 embalmed cadaveric joints (from 13 cadavers) were graded for degree of osteoarthritis, and the location of degeneration was mapped using a dissection microscope. The surfaces of 14 mildly degenerated joints were digitized and reconstructed as 3-D computer models using the Microscribe 3D-X Digitizer and the Rhinoceros 2.0 NURBS Modeling Software. This technology provided accurate and reproducible information on joint area and topography. The dorsoradial trapezial region was found to be significantly more degenerated than other quadrants in both males and females. Mean trapezial articular surface area was 197 mm 2 in males and 160 mm(2) in females; the respective mean areas for the metacarpal were 239 mm(2) in males and 184 mm(2) in females. Joints of females were found to be significantly more concave in radioulnar profile than those of males. Three bony joint recesses were consistently found, two in the radial and ulnar aspects of the trapezium and the third in the palmar surface of the metacarpal.

Impact of land cover change on the environmental hydrology characteristics in Kelantan river basin, Malaysia

NASA Astrophysics Data System (ADS)

Saadatkhah, Nader; Mansor, Shattri; Khuzaimah, Zailani; Asmat, Arnis; Adnan, Noraizam; Adam, Siti Noradzah

2016-09-01

Changing the land cover/ land use has serious environmental impacts affecting the ecosystem in Malaysia. The impact of land cover changes on the environmental functions such as surface water, loss water, and soil moisture is considered in this paper on the Kelantan river basin. The study area at the east coast of the peninsular Malaysia has suffered significant land cover changes in the recent years. The current research tried to assess the impact of land cover changes in the study area focused on the surface water, loss water, and soil moisture from different land use classes and the potential impact of land cover changes on the ecosystem of Kelantan river basin. To simulate the impact of land cover changes on the environmental hydrology characteristics, a deterministic regional modeling were employed in this study based on five approaches, i.e. (1) Land cover classification based on Landsat images; (2) assessment of land cover changes during last three decades; (3) Calculation the rate of water Loss/ Infiltration; (4) Assessment of hydrological and mechanical effects of the land cover changes on the surface water; and (5) evaluation the impact of land cover changes on the ecosystem of the study area. Assessment of land cover impact on the environmental hydrology was computed with the improved transient rainfall infiltration and grid based regional model (Improved-TRIGRS) based on the transient infiltration, and subsequently changes in the surface water, due to precipitation events. The results showed the direct increased in surface water from development area, agricultural area, and grassland regions compared with surface water from other land covered areas in the study area. The urban areas or lower planting density areas tend to increase for surface water during the monsoon seasons, whereas the inter flow from forested and secondary jungle areas contributes to the normal surface water.

Surface roughness and packaging tightness affect calcium lactate crystallization on Cheddar cheese.

PubMed

Rajbhandari, P; Kindstedt, P S

2014-01-01

Calcium lactate crystals that sometimes form on Cheddar cheese surfaces are a significant expense to manufacturers. Researchers have identified several postmanufacture conditions such as storage temperature and packaging tightness that contribute to crystal formation. Anecdotal reports suggest that physical characteristics at the cheese surface, such as roughness, cracks, and irregularities, may also affect crystallization. The aim of this study was to evaluate the combined effects of surface roughness and packaging tightness on crystal formation in smoked Cheddar cheese. Four 20-mm-thick cross-section slices were cut perpendicular to the long axis of a retail block (~300g) of smoked Cheddar cheese using a wire cutting device. One cut surface of each slice was lightly etched with a cheese grater to create a rough, grooved surface; the opposite cut surface was left undisturbed (smooth). The 4 slices were vacuum packaged at 1, 10, 50, and 90kPa (very tight, moderately tight, loose, very loose, respectively) and stored at 1°C. Digital images were taken at 1, 4, and 8 wk following the first appearance of crystals. The area occupied by crystals and number of discrete crystal regions (DCR) were quantified by image analysis. The experiment was conducted in triplicate. Effects of storage time, packaging tightness, surface roughness, and their interactions were evaluated by repeated-measures ANOVA. Surface roughness, packaging tightness, storage time, and their 2-way interactions significantly affected crystal area and DCR number. Extremely heavy crystallization occurred on both rough and smooth surfaces when slices were packaged loosely or very loosely and on rough surfaces with moderately tight packaging. In contrast, the combination of rough surface plus very tight packaging resulted in dramatic decreases in crystal area and DCR number. The combination of smooth surface plus very tight packaging virtually eliminated crystal formation, presumably by eliminating available sites for nucleation. Cut-and-wrap operations may significantly influence the crystallization behavior of Cheddar cheeses that are saturated with respect to calcium lactate and thus predisposed to form crystals. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Area G Perimeter Surface-Soil Sampling Environmental Surveillance for Fiscal Year 1998 Hazardous and Solid Waste Group (ESH-19)

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

Marquis Childs

1999-09-01

Material Disposal Area G (Area G) is at Technical Area 54 at Los Alamos National Laboratory (LANL). Area G has been the principal facility for the disposal of low-level, solid-mixed, and transuranic waste since 1957. It is currently LANL's primary facility for radioactive solid waste burial and storage. As part of the annual environmental surveillance effort at Area G, surface soil samples are collected around the facility's perimeter to characterize possible radionuclide movement off the site through surface water runoff During 1998, 39 soil samples were collected and analyzed for percent moisture, tritium, plutonium-238 and 239, cesium-137 and americium-241. Tomore » assess radionuclide concentrations, the results from these samples are compared with baseline or background soil samples collected in an undisturbed area west of the active portion Area G. The 1998 results are also compared to the results from analogous samples collected during 1996 and 1997 to assess changes over this time in radionuclide activity concentrations in surface soils around the perimeter of Area G. The results indicate elevated levels of all the radionuclides assessed (except cesium-137) exist in Area G perimeter surface soils vs the baseline soils. The comparison of 1998 soil data to previous years (1996 and 1997) indicates no significant increase or decrease in radionuclide concentrations; an upward or downward trend in concentrations is not detectable at this time. These results are consistent with data comparisons done in previous years. Continued annual soil sampling will be necessary to realize a trend if one exists. The radionuclide levels found in the perimeter surface soils are above background but still considered relatively low. This perimeter surface soil data will be used for planning purposes at Area G, techniques to prevent sediment tm.nsport off-site are implemented in the areas where the highest radionuclide concentrations are indicated.« less

40 CFR 149.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... significant amount of water to a well or spring. (b) Recharge means a process, natural or artificial, by which water is added to the saturated zone of an aquifer. (c) Recharge Area means an area in which water reaches the zone of saturation (ground water) by surface infiltration; in addition, a major recharge area...

40 CFR 149.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... significant amount of water to a well or spring. (b) Recharge means a process, natural or artificial, by which water is added to the saturated zone of an aquifer. (c) Recharge Area means an area in which water reaches the zone of saturation (ground water) by surface infiltration; in addition, a major recharge area...

Body Segment Differences in Surface Area, Skin Temperature and 3D Displacement and the Estimation of Heat Balance during Locomotion in Hominins

PubMed Central

Cross, Alan; Collard, Mark; Nelson, Andrew

2008-01-01

The conventional method of estimating heat balance during locomotion in humans and other hominins treats the body as an undifferentiated mass. This is problematic because the segments of the body differ with respect to several variables that can affect thermoregulation. Here, we report a study that investigated the impact on heat balance during locomotion of inter-segment differences in three of these variables: surface area, skin temperature and rate of movement. The approach adopted in the study was to generate heat balance estimates with the conventional method and then compare them with heat balance estimates generated with a method that takes into account inter-segment differences in surface area, skin temperature and rate of movement. We reasoned that, if the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement affect heat balance during locomotion is correct, the estimates yielded by the two methods should be statistically significantly different. Anthropometric data were collected on seven adult male volunteers. The volunteers then walked on a treadmill at 1.2 m/s while 3D motion capture cameras recorded their movements. Next, the conventional and segmented methods were used to estimate the volunteers' heat balance while walking in four ambient temperatures. Lastly, the estimates produced with the two methods were compared with the paired t-test. The estimates of heat balance during locomotion yielded by the two methods are significantly different. Those yielded by the segmented method are significantly lower than those produced by the conventional method. Accordingly, the study supports the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement impact heat balance during locomotion. This has important implications not only for current understanding of heat balance during locomotion in hominins but also for how future research on this topic should be approached. PMID:18560580

Body segment differences in surface area, skin temperature and 3D displacement and the estimation of heat balance during locomotion in hominins.

PubMed

Cross, Alan; Collard, Mark; Nelson, Andrew

2008-06-18

The conventional method of estimating heat balance during locomotion in humans and other hominins treats the body as an undifferentiated mass. This is problematic because the segments of the body differ with respect to several variables that can affect thermoregulation. Here, we report a study that investigated the impact on heat balance during locomotion of inter-segment differences in three of these variables: surface area, skin temperature and rate of movement. The approach adopted in the study was to generate heat balance estimates with the conventional method and then compare them with heat balance estimates generated with a method that takes into account inter-segment differences in surface area, skin temperature and rate of movement. We reasoned that, if the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement affect heat balance during locomotion is correct, the estimates yielded by the two methods should be statistically significantly different. Anthropometric data were collected on seven adult male volunteers. The volunteers then walked on a treadmill at 1.2 m/s while 3D motion capture cameras recorded their movements. Next, the conventional and segmented methods were used to estimate the volunteers' heat balance while walking in four ambient temperatures. Lastly, the estimates produced with the two methods were compared with the paired t-test. The estimates of heat balance during locomotion yielded by the two methods are significantly different. Those yielded by the segmented method are significantly lower than those produced by the conventional method. Accordingly, the study supports the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement impact heat balance during locomotion. This has important implications not only for current understanding of heat balance during locomotion in hominins but also for how future research on this topic should be approached.

Fabrication of novel high surface area mushroom gilled fibers and their effects on human adipose derived stem cells under pulsatile fluid flow for tissue engineering applications.

PubMed

Tuin, Stephen A; Pourdeyhimi, Behnam; Loboa, Elizabeth G

2016-05-01

The fabrication and characterization of novel high surface area hollow gilled fiber tissue engineering scaffolds via industrially relevant, scalable, repeatable, high speed, and economical nonwoven carding technology is described. Scaffolds were validated as tissue engineering scaffolds using human adipose derived stem cells (hASC) exposed to pulsatile fluid flow (PFF). The effects of fiber morphology on the proliferation and viability of hASC, as well as effects of varied magnitudes of shear stress applied via PFF on the expression of the early osteogenic gene marker runt related transcription factor 2 (RUNX2) were evaluated. Gilled fiber scaffolds led to a significant increase in proliferation of hASC after seven days in static culture, and exhibited fewer dead cells compared to pure PLA round fiber controls. Further, hASC-seeded scaffolds exposed to 3 and 6dyn/cm(2) resulted in significantly increased mRNA expression of RUNX2 after one hour of PFF in the absence of soluble osteogenic induction factors. This is the first study to describe a method for the fabrication of high surface area gilled fibers and scaffolds. The scalable manufacturing process and potential fabrication across multiple nonwoven and woven platforms makes them promising candidates for a variety of applications that require high surface area fibrous materials. We report here for the first time the successful fabrication of novel high surface area gilled fiber scaffolds for tissue engineering applications. Gilled fibers led to a significant increase in proliferation of human adipose derived stem cells after one week in culture, and a greater number of viable cells compared to round fiber controls. Further, in the absence of osteogenic induction factors, gilled fibers led to significantly increased mRNA expression of an early marker for osteogenesis after exposure to pulsatile fluid flow. This is the first study to describe gilled fiber fabrication and their potential for tissue engineering applications. The repeatable, industrially scalable, and versatile fabrication process makes them promising candidates for a variety of scaffold-based tissue engineering applications. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Morphological alterations of T24 cells on flat and nanotubular TiO2 surfaces.

PubMed

Imani, Roghayeh; Kabaso, Doron; Erdani Kreft, Mateja; Gongadze, Ekaterina; Penic, Samo; Elersic, Kristina; Kos, Andrej; Veranic, Peter; Zorec, Robert; Iglic, Ales

2012-12-01

To investigate morphological alterations of malignant cancer cells (T24) of urothelial origin seeded on flat titanium (Ti) and nanotubular TiO(2) (titanium dioxide) nanostructures. Using anodization method, TiO(2) surfaces composed of vertically aligned nanotubes of 50-100 nm diameters were produced. The flat Ti surface was used as a reference. The alteration in the morphology of cancer cells was evaluated using scanning electron microscopy (SEM). A computational model, based on the theory of membrane elasticity, was constructed to shed light on the biophysical mechanisms responsible for the observed changes in the contact area of adhesion. Large diameter TiO(2) nanotubes exhibited a significantly smaller contact area of adhesion (P<0.0001) and had more membrane protrusions (eg, microvilli and intercellular membrane nanotubes) than on flat Ti surface. Numerical membrane dynamics simulations revealed that the low adhesion energy per unit area would hinder the cell spreading on the large diameter TiO(2) nanotubular surface, thus explaining the small contact area. The reduction in the cell contact area in the case of large diameter TiO(2) nanotube surface, which does not enable formation of the large enough number of the focal adhesion points, prevents spreading of urothelial cells.

Single-row modified mason-allen versus double-row arthroscopic rotator cuff repair: a biomechanical and surface area comparison.

PubMed

Nelson, Cory O; Sileo, Michael J; Grossman, Mark G; Serra-Hsu, Frederick

2008-08-01

The purpose of this study was to compare the time-zero biomechanical strength and the surface area of repair between a single-row modified Mason-Allen rotator cuff repair and a double-row arthroscopic repair. Six matched pairs of sheep infraspinatus tendons were repaired by both techniques. Pressure-sensitive film was used to measure the surface area of repair for each configuration. Specimens were biomechanically tested with cyclic loading from 20 N to 30 N for 20 cycles and were loaded to failure at a rate of 1 mm/s. Failure was defined at 5 mm of gap formation. Double-row suture anchor fixation restored a mean surface area of 258.23 +/- 69.7 mm(2) versus 148.08 +/- 75.5 mm(2) for single-row fixation, a 74% increase (P = .025). Both repairs had statistically similar time-zero biomechanics. There was no statistical difference in peak-to-peak displacement or elongation during cyclic loading. Single-row fixation showed a higher mean load to failure (110.26 +/- 26.4 N) than double-row fixation (108.93 +/- 21.8 N). This was not statistically significant (P = .932). All specimens failed at the suture-tendon interface. Double-row suture anchor fixation restores a greater percentage of the anatomic footprint when compared with a single-row Mason-Allen technique. The time-zero biomechanical strength was not significantly different between the 2 study groups. This study suggests that the 2 factors are independent of each other. Surface area and biomechanical strength of fixation are 2 independent factors in the outcome of rotator cuff repair. Maximizing both factors may increase the likelihood of complete tendon-bone healing and ultimately improve clinical outcomes. For smaller tears, a single-row modified Mason-Allen suture technique may provide sufficient strength, but for large amenable tears, a double row can provide both strength and increased surface area for healing.

Influence of snow cover changes on surface radiation and heat balance based on the WRF model

NASA Astrophysics Data System (ADS)

Yu, Lingxue; Liu, Tingxiang; Bu, Kun; Yang, Jiuchun; Chang, Liping; Zhang, Shuwen

2017-10-01

The snow cover extent in mid-high latitude areas of the Northern Hemisphere has significantly declined corresponding to the global warming, especially since the 1970s. Snow-climate feedbacks play a critical role in regulating the global radiation balance and influencing surface heat flux exchange. However, the degree to which snow cover changes affect the radiation budget and energy balance on a regional scale and the difference between snow-climate and land use/cover change (LUCC)-climate feedbacks have been rarely studied. In this paper, we selected Heilongjiang Basin, where the snow cover has changed obviously, as our study area and used the WRF model to simulate the influences of snow cover changes on the surface radiation budget and heat balance. In the scenario simulation, the localized surface parameter data improved the accuracy by 10 % compared with the control group. The spatial and temporal analysis of the surface variables showed that the net surface radiation, sensible heat flux, Bowen ratio, temperature and percentage of snow cover were negatively correlated and that the ground heat flux and latent heat flux were positively correlated with the percentage of snow cover. The spatial analysis also showed that a significant relationship existed between the surface variables and land cover types, which was not obviously as that for snow cover changes. Finally, six typical study areas were selected to quantitatively analyse the influence of land cover types beneath the snow cover on heat absorption and transfer, which showed that when the land was snow covered, the conversion of forest to farmland can dramatically influence the net radiation and other surface variables, whereas the snow-free land showed significantly reduced influence. Furthermore, compared with typical land cover changes, e.g., the conversion of forest into farmland, the influence of snow cover changes on net radiation and sensible heat flux were 60 % higher than that of land cover changes, indicating the importance of snow cover changes in the surface-atmospheric feedback system.

Surface-Atmosphere Moisture Interactions in the Frozen Ground Regions of Eurasia.

PubMed

Ford, Trent W; Frauenfeld, Oliver W

2016-01-18

Climate models simulate an intensifying Arctic hydrologic cycle in response to climatic warming, however the role of surface-atmosphere interactions from degrading frozen ground is unclear in these projections. Using Modern-Era Retrospective Analysis for Research and Applications (MERRA) data in high-latitude Eurasia, we examine long-term variability in surface-atmosphere coupling as represented by the statistical relationship between surface evaporative fraction (EF) and afternoon precipitation. Changes in EF, precipitation, and their statistical association are then related to underlying permafrost type and snow cover. Results indicate significant positive trends in July EF in the Central Siberian Plateau, corresponding to significant increases in afternoon precipitation. The positive trends are only significant over continuous permafrost, with non-significant or negative EF and precipitation trends over isolated, sporadic, and discontinuous permafrost areas. Concurrently, increasing EF and subsequent precipitation are found to coincide with significant trends in May and June snowmelt, which potentially provides the moisture source for the observed enhanced latent heating and moisture recycling in the region. As climate change causes continuous permafrost to transition to discontinuous, discontinuous to sporadic, sporadic to isolated, and isolated permafrost disappears, this will also alter patterns of atmospheric convection, moisture recycling, and hence the hydrologic cycle in high-latitude land areas.

Analyzing contraction of full thickness skin grafts in time: Choosing the donor site does matter.

PubMed

Stekelenburg, Carlijn M; Simons, Janine M; Tuinebreijer, Wim E; van Zuijlen, Paul P M

2016-11-01

In reconstructive burn surgery full thickness skin grafts (FTSGs) are frequently preferred over split thickness skin grafts because they are known to provide superior esthetic results and less contraction. However, the contraction rate of FTSGs on the long term has never been studied. The surface area of FTSGs of consecutive patients was measured during surgery and at their regular follow up (at approximately 1, 6,13 and 52 weeks postoperatively) by means of 3D-stereophotogrammetry. Linear regression analysis was conducted to assess the influence of age, recipient- and donor site and operation indication. 38 FTSGs in 26 patients, with a mean age of 37.4 (SD 21.9) were evaluated. A significant reduction in remaining surface area to 79.1% was observed after approximately 6 weeks (p=0.002), to 85.9% after approximately 13 weeks (p=0.040) and to 91.5% after approximately 52 weeks (p=0.033). Grafts excised from the trunk showed significantly less contraction than grafts excised from the extremities (94.0% vs. 75.7% p=0.036). FTSGs showed a significant reduction in surface area, followed by a relaxation phase, but remained significantly smaller. Furthermore, the trunk should be preferred as donor site location over the extremities. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Nanofabrication of ultra-low reflectivity black silicon surfaces and devices (Presentation Recording)

NASA Astrophysics Data System (ADS)

White, Victor E.; Yee, Karl Y.; Balasubramanian, Kunjithapatham; Echternach, Pierre M.; Muller, Richard E.; Dickie, Matthew R.; Cady, Eric; Ryan, Daniel J.; Eastwood, Michael; van Gorp, Byron; Riggs, A. J. Eldorado; Zimmerman, Niel; Kasdin, N. Jeremy

2015-08-01

Optical devices with features exhibiting ultra low reflectivity on the order of 10-7 specular reflectance in the visible spectrum are required for coronagraph instruments and some spectrometers employed in space research. Nanofabrication technologies have been developed to produce such devices with various shapes and feature dimensions to meet these requirements. Infrared reflection is also suppressed significantly with chosen wafers and processes. Particularly, devices with very high (>0.9) and very low reflectivity (<10-7) on adjacent areas have been fabricated and characterized. Significantly increased surface area due to the long needle like nano structures also provides some unique applications in other technology areas. We present some of the approaches, challenges and achieved results in producing and characterizing such devices currently employed in laboratory testbeds and instruments.

Connective tissue graft vs. emdogain: A new approach to compare the outcomes.

PubMed

Sayar, Ferena; Akhundi, Nasrin; Gholami, Sanaz

2013-01-01

The aim of this clinical trial study was to clinically evaluate the use of enamel matrix protein derivative combined with the coronally positioned flap to treat gingival recession compared to the subepithelial connective tissue graft by a new method to obtain denuded root surface area. Thirteen patients, each with two or more similar bilateral Miller class I or II gingival recession (40 recessions) were randomly assigned to the test (enamel matrix protein derivative + coronally positioned flap) or control group (subepithelial connective tissue graft). Recession depth, width, probing depth, keratinized gingival, and plaque index were recorded at baseline and at one, three, and six months after treatment. A stent was used to measure the denuded root surface area at each examination session. Results were analyzed using Kolmogorov-Smirnov, Wilcoxon, Friedman, paired-sample t test. The average percentages of root coverage for control and test groups were 63.3% and 55%, respectively. Both groups showed significant keratinized gingival increase (P < 0.05). Recession depth decreased significantly in both groups. Root surface area was improved significantly from baseline with no significant difference between the two study groups (P > 0.05). The results of Friedman test were significant for clinical indices (P < 0.05), except for probing depth in control group (P = 0.166). Enamel matrix protein derivative showed the same results as subepithelial connective tissue graft with relatively easy procedure to perform and low patient morbidity.

Upwelling Dynamic Based on Satellite and INDESO Data in the Flores Sea

NASA Astrophysics Data System (ADS)

Kurniawan, Reski; Suriamihardja, D. A.; Hamzah Assegaf, Alimuddin

2018-03-01

Upwelling phenomenon is crucial to be forecasted, mainly concerning the information of potential fishery areas. Utilization of calibrated model for recorded upwelling such as INDESO gives benefit for historical result up to the present time. The aim of this study is to estimate areas and seasons of upwelling occurrences in the Flores Sea using data assimilation of satellite and modeling result. This study uses sea surface temperature, chlorophyll-a data from level 3 of MODIS image and sea surface height from satellite Jason-2 monthly for three years (2014-2016) and INDESO model data for sea surface temperature, sea surface height, and chlorophyll-a daily for three years (2014-2016). The upwelling is indicated by declining of sea surface temperature, sea surface height and increasing of chlorophyll-a. Verification is conducted by comparing the model result with recorded MODIS satellite image. The result shows that the area of southern Makassar Strait having occurrences of upwelling phenomenon every year starting in June, extended to July and August. The strongest upwelling occurred in 2015 covering more or less the area of 23,000 km2. The relation of monthly data of satellite has significantly correlated with daily data of INDESO model

Occupational Exposure to Cobalt and Tungsten in the Swedish Hard Metal Industry: Air Concentrations of Particle Mass, Number, and Surface Area

PubMed Central

Bryngelsson, Ing-Liss; Pettersson, Carin; Husby, Bente; Arvidsson, Helena; Westberg, Håkan

2016-01-01

Exposure to cobalt in the hard metal industry entails severe adverse health effects, including lung cancer and hard metal fibrosis. The main aim of this study was to determine exposure air concentration levels of cobalt and tungsten for risk assessment and dose–response analysis in our medical investigations in a Swedish hard metal plant. We also present mass-based, particle surface area, and particle number air concentrations from stationary sampling and investigate the possibility of using these data as proxies for exposure measures in our study. Personal exposure full-shift measurements were performed for inhalable and total dust, cobalt, and tungsten, including personal real-time continuous monitoring of dust. Stationary measurements of inhalable and total dust, PM2.5, and PM10 was also performed and cobalt and tungsten levels were determined, as were air concentration of particle number and particle surface area of fine particles. The personal exposure levels of inhalable dust were consistently low (AM 0.15mg m−3, range <0.023–3.0mg m−3) and below the present Swedish occupational exposure limit (OEL) of 10mg m−3. The cobalt levels were low as well (AM 0.0030mg m−3, range 0.000028–0.056mg m−3) and only 6% of the samples exceeded the Swedish OEL of 0.02mg m−3. For continuous personal monitoring of dust exposure, the peaks ranged from 0.001 to 83mg m−3 by work task. Stationary measurements showed lower average levels both for inhalable and total dust and cobalt. The particle number concentration of fine particles (AM 3000 p·cm−3) showed the highest levels at the departments of powder production, pressing and storage, and for the particle surface area concentrations (AM 7.6 µm2·cm−3) similar results were found. Correlating cobalt mass-based exposure measurements to cobalt stationary mass-based, particle area, and particle number concentrations by rank and department showed significant correlations for all measures except for particle number. Linear regression analysis of the same data showed statistically significant regression coefficients only for the mass-based aerosol measures. Similar results were seen for rank correlation in the stationary rig, and linear regression analysis implied significant correlation for mass-based and particle surface area measures. The mass-based air concentration levels of cobalt and tungsten in the hard metal plant in our study were low compared to Swedish OELs. Particle number and particle surface area concentrations were in the same order of magnitude as for other industrial settings. Regression analysis implied the use of stationary determined mass-based and particle surface area aerosol concentration as proxies for various exposure measures in our study. PMID:27143598

Effects of decontamination work on riverine radiocaesium activity concentrations in Fukushima affected area

NASA Astrophysics Data System (ADS)

Taniguchi, K.; Onda, Y.; Yoshimura, K.; Smith, H.; Brake, W.; Kubo, T.; Kuramoto, T.; Sato, T.; Onuma, S.

2016-12-01

Radionuclides such as Cs-134 and Cs-137 were widely distributed in the area affected by the accident at Fukushima Daiichi nuclear power plant. The radionuclides were deposited on the surface, absorbed by soil particles, and transported via river systems to Pacific Ocean due to rainfall events. In order to reduce air dose rate surrounding residential area, decontamination works have been conducted between 2013 and 2016 Fiscal Years. In paddy field and farmland contaminated by the fallout, 5 cm of surface soil was stripped, and then clean sands put on the surface. This work could reduce radiocaesium inventory, while the coverage of vegetation was significantly decreased. Therefore, runoff characteristics in the decontaminated area were different before and after the decontamination. Activity concentrations of particulate Cs-137 were measured in Abukuma river system and 8 small catchments located in coastal zone of Fukushima affected area. In all monitoring sites, Cs-137 concentrations have decreased over an entire monitoring period. Kuchibuto river, which is a tributary of Abukuma river showed significant effect of decontamination. In Yamakiya district, in the watershed of the tributary, the decontamination work had conducted from 2013 FY to December 2015. Particulate Cs-137 concentration at two monitoring sites located in the district showed around 30% of decline in the beginning of 2014 FY whereas the decline was not so significant at sites in lower reach of the tributary. Decontaminated paddy field and farmland can be judged as the important source of suspended sediments in the tributary.

The application of phase contrast X-ray techniques for imaging Li-ion battery electrodes

NASA Astrophysics Data System (ADS)

Eastwood, D. S.; Bradley, R. S.; Tariq, F.; Cooper, S. J.; Taiwo, O. O.; Gelb, J.; Merkle, A.; Brett, D. J. L.; Brandon, N. P.; Withers, P. J.; Lee, P. D.; Shearing, P. R.

2014-04-01

In order to accelerate the commercialization of fuel cells and batteries across a range of applications, an understanding of the mechanisms by which they age and degrade at the microstructural level is required. Here, the most widely commercialized Li-ion batteries based on porous graphite based electrodes which de/intercalate Li+ ions during charge/discharge are studied by two phase contrast enhanced X-ray imaging modes, namely in-line phase contrast and Zernike phase contrast at the micro (synchrotron) and nano (laboratory X-ray microscope) level, respectively. The rate of charge cycling is directly dependent on the nature of the electrode microstructure, which are typically complex multi-scale 3D geometries with significant microstructural heterogeneities. We have been able to characterise the porosity and the tortuosity by micro-CT as well as the morphology of 5 individual graphite particles by nano-tomography finding that while their volume varied significantly their sphericity was surprisingly similar. The volume specific surface areas of the individual grains measured by nano-CT are significantly larger than the total volume specific surface area of the electrode from the micro-CT imaging, which can be attributed to the greater particle surface area visible at higher resolution.

Regional differences in the surface temperature of Naked Neck laying hens in a semi-arid environment.

PubMed

de Souza, João Batista Freire; de Arruda, Alex Martins Varela; Domingos, Hérica Girlane Tertulino; de Macedo Costa, Leonardo Lelis

2013-05-01

The aim of this study was to evaluate the regional differences in the surface temperature of Naked Neck hens that were subjected to different temperatures in a semi-arid environment. The surface temperature was measured in four body regions (face, neck, legs and feathered area) of 60 Naked Neck hens. The following environmental variables were measured at the center of the shed: the black globe temperature (T G ), air temperature (T A ), wind speed (U) and relative humidity (R H ). The T A was divided into three classes: 1 (24.0-26.0 °C), 2 (26.1-28.9 °C) and 3 (29.0-31.0 °C). An analysis of variance was performed by the least squares method and a comparison of the means by the Tukey-Kramer test. The results showed a significant effect of T A class, the body region and the interaction between these two effects on the surface temperature. There was no significant difference between the T A classes for the face and neck. The legs and feathered area showed significant differences between the T A classes. Regarding the effect of body regions within each T A class, there was a significant difference among all regions in the three T A classes. In all T A classes the neck had the highest average followed by the face and legs. The feathered area showed the lowest average of the different T A classes. In conclusion, this study showed that there are regional differences in the surface temperature of Naked Neck hens, with the legs acting as thermal windows.

INTERFRAGMENTARY SURFACE AREA AS AN INDEX OF COMMINUTION SEVERITY IN CORTICAL BONE IMPACT

PubMed Central

Beardsley, Christina L.; Anderson, Donald D.; Marsh, J. Lawrence; Brown, Thomas D.

2008-01-01

Summary A monotonic relationship is expected between energy absorption and fracture surface area generation for brittle solids, based on fracture mechanics principles. It was hypothesized that this relationship is demonstrable in bone, to the point that on a continuous scale, comminuted fractures created with specific levels of energy delivery could be discriminated from one another. Using bovine cortical bone segments in conjunction with digital image analysis of CT fracture data, the surface area freed by controlled impact fracture events was measured. The results demonstrated a statistically significant (p<0.0001) difference in measured de novo surface area between three specimen groups, over a range of input energies from 0.423 to 0.702 J/g. Local material properties were also incorporated into these measurements via CT Hounsfield intensities. This study confirms that comminution severity of bone fractures can indeed be measured on a continuous scale, based on energy absorption. This lays a foundation for similar assessments in human injuries. PMID:15885492

Comparison of plantar pressures and contact area between normal and cavus foot.

PubMed

Fernández-Seguín, Lourdes M; Diaz Mancha, Juan Antonio; Sánchez Rodríguez, Raquel; Escamilla Martínez, Elena; Gómez Martín, Beatriz; Ramos Ortega, Javier

2014-02-01

In pes cavus, the medial longitudinal arch elevation reduces the contact surface area and consequently increases the corresponding plantar pressure measurements. This poor distribution of loads may produce associated pathology and pain in this or other areas of the body. Normal reference values need to be established in order to determine which patterns are prone to pathology. To compare the plantar pressures and weight-bearing surface in a population with pes cavus to a population with neutral feet. The sample comprised 68 adults, 34 with pes cavus and 34 with neutral feet. The Footscan USB Gait Clinical System(®) was used as a platform to measure the total contact area and plantar pressure under the forefoot, midfoot, hindfoot, each metatarsal head, and the overall metatarsal area. A statistical analysis of the data was performed using Student's t-test for independent samples. The pes cavus subjects showed a significant reduction in their weight-bearing area [neutral feet: 165.04 ( ± 20.68) cm(2); pes cavus: 118.26 ( ± 30.31) cm(2); p < 0.001] and significantly increased pressures under all zones of the forefoot except the fifth metatarsal [metatarsal pressure: in neutral feet 503,797 ( ± 9.32) kPa; in pes cavus 656.12 ( ± 22.39) kPa; p < 0.001]. Compared to neutral feet, pes cavus feet show a reduction in total contact surface and the load under the first toe. A significant increase is present in the load under the metatarsal areas, but the relative distribution of this load is similar in both groups. Copyright © 2013 Elsevier B.V. All rights reserved.

Bond strength of the porcelain repair system to all-ceramic copings and porcelain.

PubMed

Lee, Sang J; Cheong, Chan Wook; Wright, Robert F; Chang, Brian M

2014-02-01

The purpose of this study was to investigate the shear bond strength of the porcelain repair system on alumina and zirconia core ceramics, comparing this strength with that of veneering porcelain. Veneering ceramic (n = 12), alumina core (n = 24), and zirconia core (n = 24) blocks measuring 10 × 5 × 5 mm(3) were fabricated. Veneering ceramic blocks were used as the control. Alumina and zirconia core blocks were divided into 2 groups (n = 12 each), and a slot (2 × 2 × 4 mm(3)) filled with veneering ceramics was prepared into one of the alumina and zirconia core groups (n = 12). Followed by surface treatments of micro-abrasion with 30 μm alumina particles, etching with 35% phosphoric acid and silane primer and bond, composite resin blocks (2 × 2 × 2 mm(3)) were built up and light polymerized onto the treated surfaces by 3 configurations: (a) composite blocks bonded onto veneering ceramic surface alone, (b) composite blocks bonded onto alumina core or zirconia core surfaces, (c) a 50% surface area of the composite blocks bonded to veneering ceramics and the other 50% surface area of the composite blocks to alumina core or zirconia core surfaces. The shear bond strength of the composite to each specimen was tested by a universal testing machine at a 0.5 mm/min crosshead speed. The shear bond strength was analyzed by unpaired t-tests for within the configuration groups and ANOVA for among the different configuration groups. When the mean shear bond strength was compared within groups of the same configuration, there were no statistically significant differences. Comparison of the shear bond strength among groups of different configurations revealed statistically significant differences. The mean shear bond strength of composite onto 100% veneering ceramic surface and composite onto 50% veneering 50% all-ceramic cores was statistically higher than that of composite onto 100% all-ceramic cores; however, the differences of the shear bond strength of composite bonded only onto the veneering ceramic surface were not statistically significant from those of 50% surface area of composite bonded onto all-ceramic cores. No statistically significant differences in the bond strength of a porcelain repair system to alumina and zirconia copings were observed. Increasing the surface of veneering ceramics to a porcelain repair system improved the repair material's bond strength. © 2013 by the American College of Prosthodontists.

The Effect of Rebamipide on Ocular Surface Disorders Induced by Latanoprost and Timolol in Glaucoma Patients.

PubMed

Tokuda, Naoto; Kitaoka, Yasushi; Matsuzawa, Akiko; Miyamoto, Junsuke; Sakae, Shinsuke; Munemasa, Yasunari; Takagi, Hitoshi

2015-01-01

Purpose. To examine the efficacy of ophthalmic rebamipide suspensions on ocular surface disorders induced by antiglaucoma eye drops. Patients and Methods. Forty eyes of 40 patients receiving latanoprost (0.005%) and timolol (0.5%) were included in this randomized prospective study. The patients were randomly divided into two groups (n = 20): the rebamipide-treated group and control group. Changes in intraocular pressure, tear film break-up time (TBUT), and corneal epithelial barrier function were evaluated at baseline, 4 weeks, and 8 weeks after rebamipide administration. Furthermore, superficial punctate keratopathy severity was evaluated by scoring the lesion area and density. Results. There was no significant difference in intraocular pressure before and after rebamipide treatment. However, corneal epithelial barrier function improved significantly 4 and 8 weeks after rebamipide treatment. TBUT was partially, but significantly, increased (P = 0.02) 8 weeks after rebamipide treatment, whereas no significant change was observed at 4 weeks. Additionally, a significant decrease in area and density of keratopathy was observed 8 weeks after rebamipide treatment but not at 4 weeks. The control group showed no significant difference compared to baseline. Conclusions. Our data suggests that rebamipide treatment may reduce the occurrence of drug-induced ocular surface disorder.

Wipe-rinse technique for quantitating microbial contamination on large surfaces.

PubMed Central

Kirschner, L E; Puleo, J R

1979-01-01

The evaluation of an improved wipe-rinse technique for the bioassay of large areas was undertaken due to inherent inadequacies in the cotton swab-rinse technique to which assay of spacecraft is currently restricted. Four types of contamination control cloths were initially tested. A polyester-bonded cloth (PBC) was selected for further evaluation because of its superior efficiency and handling characteristics. Results from comparative tests with PBC and cotton swabs on simulated spacecraft surfaces indicated a significantly higher recovery efficiency for the PBC than for the cotton (90.4 versus 75.2%). Of the sampling areas sites studied, PBC was found to be most effective on surface areas not exceeding 0.74 m2 (8.0 feet 2). PMID:394682

Wipe-rinse technique for quantitating microbial contamination on large surfaces

NASA Technical Reports Server (NTRS)

Kirschner, L. E.; Puleo, J. R.

1979-01-01

The evaluation of an improved wipe-rinse technique for the bioassay of large areas was undertaken due to inherent inadequacies in the cotton swab-rinse technique to which assay of spacecraft is currently restricted. Four types of contamination control cloths were initially tested. A polyester-bonded cloth (PBC) was selected for further evaluation because of its superior efficiency and handling characteristics. Results from comparative tests with PBC and cotton swabs on simulated spacecraft surfaces indicated a significantly higher recovery efficiency for the PBC than for the cotton (90.4 versus 75.2%). Of the sampling area sites studied, PBC was found to be most effective on surface areas not exceeding 0.74 sq m (8.0 sq ft).

A surface fuel classification for estimating fire effects

Treesearch

Duncan C. Lutes; Robert E. Keane; John F. Caratti

2009-01-01

We present a classification of duff, litter, fine woody debris, and logs that can be used to stratify a project area into sites with fuel loading that yield significantly different emissions and maximum soil surface temperature. Total particulate matter smaller than 2.5?m in diameter and maximum soil surface temperature were simulated using the First...

Improved capacity to evaluate changes in intestinal mucosal surface area using mathematical modeling.

PubMed

Greig, Chasen J; Cowles, Robert A

2017-07-01

Quantification of intestinal mucosal growth typically relies on morphometric parameters, commonly villus height, as a surrogate for presumed changes in mucosal surface area (MSA). We hypothesized that using mathematical modeling based on multiple unique measurements would improve discrimination of the effects of interventions on MSA compared to standard measures. To determine the ability of mathematical modeling to resolve differences in MSA, a mouse model with enhanced serotonin (5HT) signaling known to stimulate mucosal growth was used. 5-HT signaling is potentiated by targeting the serotonin reuptake transporter (SERT) molecule. Selective serotonin reuptake inhibitor-treated wild-type (WT-SSRI), SERT-knockout (SERTKO), and wild-type C57Bl/6 (WT) mice were used. Distal ileal sections were H&E-stained. Villus height (VH), width (VW), crypt width (CW), and bowel diameter were used to calculate surface area enlargement factor (SEF) and MSA. VH alone for SERTKO and SSRI was significantly increased compared to WT, without a difference between SERTKO and WT-SSRI. VW and CW were significantly decreased for both SERTKO and WT-SSRI compared to WT, and VW for WT-SSRI was also decreased compared to SERTKO. These changes increased SEF and MSA for SERTKO and WT-SSRI compared to WT. Additionally, SEF and MSA were significantly increased for WT-SSRI compared to SERTKO. Mathematical modeling provides a valuable tool for differentiating changes in intestinal MSA. This more comprehensive assessment of surface area does not appear to correlate linearly with standard morphometric measures and represents a more comprehensive method for discriminating between therapies aimed at increasing functional intestinal mucosa. © 2017 Wiley Periodicals, Inc.

The effect of Tai Chi exercises on postural stability and control in older patients with knee osteoarthritis.

PubMed

Ghandali, Elham; Moghadam, Saeed Talebian; Hadian, Mohammad Reza; Olyaei, Gholamreza; Jalaie, Shohreh; Sajjadi, Elaheh

2017-07-01

A few studies have examined the effect of Tai Chi on balance in elder patients with knee osteoarthritis (OA). The aim of this study was to determine the balance measures in elder patients with knee OA after Tai Chi exercises. For this purpose 14 females and 6 males with knee OA were chosen. Area and mean velocity of the center of pressure movements (CoP) were measured by force plate in standing positions (on foam and rigid surfaces). The measurements of area and mean velocity of CoP were performed before and after 60 min of Tai Chi sessions (twice a week for 8 weeks). The results showed that the area of CoP in standing position on rigid surface was significantly decreased (P < 0.01) after Tai Chi exercises. Furthermore, the mean velocity of CoP was significantly decreased after Tai Chi exercises on both rigid and foam surfaces (P < 0.001). Our study also indicated that changes in surfaces (rigid and foam) would cause significant differences regarding the area of CoP in standing positions. However, similar findings were not found regarding the mean velocity of CoP. Considering the effects of Tai Chi on mean velocity of CoP, it might be concluded that motor control and postural stability improvements have occurred. Therefore, based on these results, Tai Chi exercises could be recommended for elder patients with knee OA as part of their rehabilitation and physical therapy protocols. Copyright © 2016. Published by Elsevier Ltd.

Cortical thickness and surface area correlates with cognitive dysfunction among first-episode psychosis patients.

PubMed

Haring, L; Müürsepp, A; Mõttus, R; Ilves, P; Koch, K; Uppin, K; Tarnovskaja, J; Maron, E; Zharkovsky, A; Vasar, E; Vasar, V

2016-07-01

In studies using magnetic resonance imaging (MRI), some have reported specific brain structure-function relationships among first-episode psychosis (FEP) patients, but findings are inconsistent. We aimed to localize the brain regions where cortical thickness (CTh) and surface area (cortical area; CA) relate to neurocognition, by performing an MRI on participants and measuring their neurocognitive performance using the Cambridge Neuropsychological Test Automated Battery (CANTAB), in order to investigate any significant differences between FEP patients and control subjects (CS). Exploration of potential correlations between specific cognitive functions and brain structure was performed using CANTAB computer-based neurocognitive testing and a vertex-by-vertex whole-brain MRI analysis of 63 FEP patients and 30 CS. Significant correlations were found between cortical parameters in the frontal, temporal, cingular and occipital brain regions and performance in set-shifting, working memory manipulation, strategy usage and sustained attention tests. These correlations were significantly dissimilar between FEP patients and CS. Significant correlations between CTh and CA with neurocognitive performance were localized in brain areas known to be involved in cognition. The results also suggested a disrupted structure-function relationship in FEP patients compared with CS.

In Vitro Comparison Of Fluoride Gel Alone and in Combination With Er,Cr:YSGG Laser on Reducing White Spot Lesions in Primary Teeth.

PubMed

Molaasadollah, Fatemeh; Asnaashari, Mohammad; Mashhadi Abbas, Fatemeh; Jafary, Maral

2017-01-01

Introduction: Laser therapy has been suggested as a method for caries-prevention, and ErCr:YSGG laser is increasingly used in dentistry. This study aimed to compare the efficacy of fluoride gel alone and in conjunction with Er,Cr:YSGG laser for remineralization of white spot lesions (WSLs) in primary teeth. Methods: This study was conducted on 20 primary teeth with WSLs extracted for orthodontic reasons. Three sections were made of each tooth at the site of WSLs. The surface area of WSLs was measured under a stereomicroscope at ×25 magnification. Samples were assigned to 3 groups of control (group 1), exposure to 1.23% APF gel for 4 minutes (group 2) and Er,Cr:YSGG laser (0.5 W power, 20 Hz frequency, 60% water, 40% air, pulse duration of 5±1 seconds) plus fluoride (group 3). All samples were stored in artificial saliva for 10 days and then the surface area of the WSLs was measured again under a stereomicroscope. Data were analyzed using the Kruskal-Wallis, MannWhitney and Wilcoxon signed rank tests. Results: The reduction in surface area of the WSLs was significantly different between the control and fluoride ( P <0.001) and also the control and laser plus fluoride groups ( P <0.001); the difference between fluoride and laser plus fluoride groups was not significant ( P =0.265). Comparison of the surface area of WSLs before and after the intervention showed no significant difference in group one ( P =0.737) while this difference in groups 2 ( P <0.001) and 3 ( P <0.001) was statistically significant. Conclusion: The results showed that Er,Cr:YSGG laser irradiation plus 1.23% APF gel was not significantly different from the application of fluoride gel alone in enhancing the remineralization of WSLs.

Contemporary suspended sediment dynamics within two partly glacierized mountain drainage basins in western Norway (Erdalen and Bødalen, inner Nordfjord)

NASA Astrophysics Data System (ADS)

Beylich, Achim A.; Laute, Katja; Storms, Joep E. A.

2017-06-01

This paper focuses on environmental controls, spatiotemporal variability and rates of contemporary fluvial suspended sediment transport in the neighboring, partly glacierized and steep Erdalen (79.5 km2) and Bødalen (60.1 km2) drainage basins in the fjord landscape of the inner Nordfjord in western Norway. Field work, including extended samplings and measurements, was conducted since 2004 in Erdalen and since 2008 in Bødalen. The distinct intra- and inter-annual temporal variability of suspended sediment transport found is mostly controlled by meteorological events, with most suspended sediment transport occurring during pluvial events in autumn (September-November), followed by mostly thermally determined glacier melt in summer (July-August), and by mostly thermally determined snowmelt in spring (April-June). Extreme rainfall events (> 70 mm d- 1) in autumn can trigger significant debris-flow activity that can cause significant transfers of suspended sediments from ice-free surface areas with sedimentary covers into main stream channels and is particularly important for fluvial suspended sediment transport. In years with occurring relevant debris-flow activity the total annual drainage-basin wide suspended sediment yields are strongly determined by these single extreme events. The proportion of glacier coverage, followed by steepness of slopes, and degree of vegetation cover in ice-free surface areas with sedimentary covers are the main controls for the detected spatial variability of suspended sediment yields. The contemporary sediment supply from glacierized surface areas and the Jostedalsbreen ice cap through different defined outlet glaciers shows a high spatial variability. The fact that the mean annual suspended sediment yield of Bødalen is with 31.3 t km- 2 yr- 1 almost twice as high as the mean annual suspended sediment yield of Erdalen (16.4 t km- 2 yr- 1) is to a large extent explained by the higher proportion of glacier coverage in Bødalen (38% of the drainage basin surface area) as compared to Erdalen (18% of the drainage basin surface area) and by a significantly higher sediment yield from the glacierized area of the Bødalen drainage basin compared to the glacierized surface area in Erdalen. When looking at the total annual mass of suspended sediments being fluvially exported from both entire drainage basin systems, the total amount of suspended sediments coming from the ice-free drainage basin surface areas altogether dominates over the total amount of suspended sediments coming from the glacierized surface area of both drainage basins. Drainage-basin wide annual suspended sediment yields are rather low when compared with yields of other partly glacierized drainage basin systems in Norway and in other cold climate environments worldwide, which is mainly due to the high resistance of the predominant gneisses towards glacial erosion and weathering, the altogether only small amounts of sediments being available within the entire drainage basin systems, the stable and nearly closed vegetation cover in the ice-free surface areas with sedimentary covers, and the efficiency of proglacial lakes in trapping sediments supplied by defined outlet glaciers. Both contemporary and long-term suspended sediment yields are altogether supply-limited. Contemporary suspended sediment transport accounts for nearly two-thirds of the total fluvial transport and, accordingly, plays an important role within the sedimentary budgets of the entire Erdalen and Bødalen drainage basins.

Surface water change as a significant contributor to global evapotranspiration change

NASA Astrophysics Data System (ADS)

Zhan, S.; Song, C.

2017-12-01

Water comprises a critical component of global/regional hydrological and biogeochemical cycles and is essential to all organisms including humans. In the past several decades, climate change has intensified the hydrological cycle, with significant implications for ecosystem services and feedback to regional and global climate. Evapotranspiration (ET) as a linking mechanism between land surface and atmosphere is central to the water cycle and an excellent indicator of the intensity of water cycle. Knowledge of the temporal changes of ET is crucial for accurately estimating global or regional water budgets and better understanding climate and hydrological interactions. While studies have examined changes in global ET, they were conducted using a constant land and surface water (SW) area. However, as many studies have found that global SW is very dynamic and their surface areas have generally been increasing since the 1980s. The conversion from land to water and vice versa significantly changes the local ET since water bodies evaporate at a rate that can be much higher than that of the land. Here, we quantify the global changes in ET caused by such land-water conversion using remotely-sensed SW area and various ET and potential ET products. New SW and lost SW between circa-1985 and circa-2015 were derived from remote sensing and were used to modify the local ET estimates. We found an increase in ET in all continents as consistent with the net increase in SW area. The increasing SW area lead to a global increase in ET by 30.38 ± 5.28 km3/yr. This is a significant contribution when compared to the 92.95 km3/yr/yr increase in ET between 1982-1997 and 103.43 km3/yr/yr decrease between 1998-2008 by Jung et al., (2010) assuming a constant SW. The results enhance our understanding of the water fluxes between the land and atmosphere and supplement land water budget estimates. We conclude that changes in SW lead to a significant change in global ET that cannot be neglected in global ET trend studies and should also be included in global water budget studies.

Remote sensing of the surface emissivity at 9 microns over the globe. [over desert regions with IR Interferometer Spectrometer data

NASA Technical Reports Server (NTRS)

Prabhakara, C.; Dalu, G.

1976-01-01

The infrared spectral measurements made by the Nimbus 4 infrared interferometer spectrometer (Iris) for a period of about 10 months are used to study the surface emissivity properties over the globe. It is found that the surface emissivity at 9 microns, as measured by Iris with a circular field of view of about 100-km diameter, is significantly less than unity over arid and semiarid areas. The spectral features in the 8-12-micron window observed over these lands reveal emissivity characteristics essentially due to quartz (SiO2). It is found that these emissivity features are significantly weakened by the presence of clay, clay horizons, or pedogenic horizons in the soil. Low emissivity is observed over sandy or sandy loam areas (psamments) with no clay or pedogenic horizons.

Evaluation of urban surface parameterizations in the WRF model using measurements during the Texas Air Quality Study 2006 field campaign

NASA Astrophysics Data System (ADS)

Lee, S.-H.; Kim, S.-W.; Angevine, W. M.; Bianco, L.; McKeen, S. A.; Senff, C. J.; Trainer, M.; Tucker, S. C.; Zamora, R. J.

2010-10-01

The impact of urban surface parameterizations in the WRF (Weather Research and Forecasting) model on the simulation of local meteorological fields is investigated. The Noah land surface model (LSM), a modified LSM, and a single-layer urban canopy model (UCM) have been compared, focusing on urban patches. The model simulations were performed for 6 days from 12 August to 17 August during the Texas Air Quality Study 2006 field campaign. Analysis was focused on the Houston-Galveston metropolitan area. The model simulated temperature, wind, and atmospheric boundary layer (ABL) height were compared with observations from surface meteorological stations (Continuous Ambient Monitoring Stations, CAMS), wind profilers, the NOAA Twin Otter aircraft, and the NOAA Research Vessel Ronald H. Brown. The UCM simulation showed better results in the comparison of ABL height and surface temperature than the LSM simulations, whereas the original LSM overestimated both the surface temperature and ABL height significantly in urban areas. The modified LSM, which activates hydrological processes associated with urban vegetation mainly through transpiration, slightly reduced warm and high biases in surface temperature and ABL height. A comparison of surface energy balance fluxes in an urban area indicated the UCM reproduces a realistic partitioning of sensible heat and latent heat fluxes, consequently improving the simulation of urban boundary layer. However, the LSMs have a higher Bowen ratio than the observation due to significant suppression of latent heat flux. The comparison results suggest that the subgrid heterogeneity by urban vegetation and urban morphological characteristics should be taken into account along with the associated physical parameterizations for accurate simulation of urban boundary layer if the region of interest has a large fraction of vegetation within the urban patch. Model showed significant discrepancies in the specific meteorological conditions when nocturnal low-level jets exist and a thermal internal boundary layer over water forms.

Near Surface Thermal Stratification during Summer at Summit, Greenland, and its Impact on MODIS-derived Surface Temperatures

NASA Astrophysics Data System (ADS)

Adolph, A. C.; Albert, M. R.; Hall, D. K.

2017-12-01

As rapid warming of the Arctic occurs, it is imperative that we monitor climate parameters such as temperature over large areas to understand and predict the extent of climate changes. Temperatures are often tracked using in-situ 2 m air temperatures, but in remote locations such as on the Greenland Ice Sheet, temperature can be studied more comprehensively using remote sensing techniques. Because of the presence of surface-based temperature inversions in ice-covered areas, differences between 2 m air temperature and 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 at Summit Station in Greenland to study surface temperature using the following measurements: skin temperature measured by IR sensors, thermochrons, and thermocouples; 2 m air temperature measured by a NOAA meteorological station; and two different MODerate-resolution Imaging Spectroradiometer (MODIS) surface temperature products. We confirm prior findings that in-situ 2 m air temperature is often significantly higher in the summer than in-situ skin temperature when incoming solar radiation and wind speed are low. This inversion may account for biases in previous MODIS surface temperature studies that used 2 m air temperature for validation. As compared to the in-situ IR skin temperature measurements, the MOD/MYD11 Collection 6 surface-temperature standard product has an RMSE of 1.0°C, and that the MOD29 Collection 6 product has an RMSE of 1.5°C, spanning a range of temperatures from -35°C to -5°C. For our study area and time series, MODIS surface temperature products agree with skin temperatures better than many previous studies have indicated, especially at temperatures below -20°C where other studies found a significant cold bias. Further investigation at temperatures below -35°C is warranted to determine if this bias does indeed exist.

SCREENING TO IDENTIFY AND PREVENT URBAN STORM WATER PROBLEMS: ESTIMATING IMPERVIOUS AREA ACCURATELY AND INEXPENSIVELY

EPA Science Inventory

Complete identification and eventual prevention of urban water quality problems pose significant monitoring, "smart growth" and water quality management challenges. Uncontrolled increase of impervious surface area (roads, buildings, and parking lots) causes detrimental hydrologi...

The use of ERTS/LANDSAT imagery in relation to airborne remote sensing for terrain analysis in western Queensland, Australia

NASA Technical Reports Server (NTRS)

Cole, M. M. (Principal Investigator); Owen-Jones, S.

1976-01-01

The author has identified the following significant results. Distinctive spectral signatures were found associated with areas of near surface bedrock with covered ground east of Dugald River and along the Thorntonia River valley west of Lady Annie. Linears identified in the Dugald River area on LANDSAT 2 imagery taken in March and July 1975 over the Cloncurry-Dobbyn area, displayed preferred orientation. A linear group with NE-SW orientation was identified in the Lady Annie area. In this area, the copper mineralization in the Mt. Kelly area occurs along a well marked linear with NNW/SSE direction apparent on images for March, September, and November 1975. Geobotanical anomalies provided surface expression of the copper deposits in Mt. Kelley.

Habitat of calling blue and fin whales in the Southern California Bight

NASA Astrophysics Data System (ADS)

Sirovic, A.; Chou, E.; Roch, M. A.

2016-02-01

Northeast Pacific blue whale B calls and fin whale 20 Hz calls were detected from passive acoustic data collected over seven years at 16 sites in the Southern California Bight (SCB). Calling blue whales were most common in the coastal areas, during the summer and fall months. Fin whales began calling in fall and continued through winter, in the southcentral SCB. These data were used to develop habitat models of calling blue and fin whales in areas of high and low abundance in the SCB, using remotely sensed variables such as sea surface temperature, sea surface height, chlorophyll a, and primary productivity as model covariates. A random forest framework was used for variable selection and generalized additive models were developed to explain functional relationships, evaluate relative contribution of each significant variable, and investigate predictive abilities of models of calling whales. Seasonal component was an important feature of all models. Additionally, areas of high calling blue and fin whale abundance both had a positive relationship with the sea surface temperature. In areas of lower abundance, chlorophyll a concentration and primary productivity were important variables for blue whale models and sea surface height and primary productivity were significant covariates in fin whale models. Predictive models were generally better for predicting general trends than absolute values, but there was a large degree of variation in year-to-year predictability across different sites.

Synthesis and Properties of Cross-Linked Polyamide Aerogels

NASA Technical Reports Server (NTRS)

Williams, Jarrod; Meador, Mary Ann; McCorkle, Linda

2014-01-01

We report our ongoing research on polyamide aerogels made by step growth polymerization using a combination of terephthaloyl chloride, isophthaloyl chloride and m-phenylenediamine. Crosslinking of the amine capped polymer chains with 1,3,5-benzenetricarbonyl trichloride causes gelation in as little as two to five minutes. Removing the reaction solvent is accomplished through solvent exchange, followed by drying using supercritical CO2 extraction to give colorless aerogels with densities ranging from 0.07 to 0.33 grams per cubic centimeter and surface areas as high as 440 square meters per gram. Statistical experimental design methodology has been utilized to investigate dependence of properties of these aerogels, such as density, compressive modulus, and surface area, on changes in fabrication parameters including formulated number of amide oligomer repeat units (n-value), acid chloride (meta, para or combination), and solids concentration of solution used for gelation. For example, the density of these materials was found to be dependent on the acid chloride type and the solids concentration, but n was not a significant variable. However, surface area was significantly influenced by all three parameters. The polyamide aerogels represent a potential cost savings over previously reported polyimide aerogels, since monomers are all inexpensive and commercially available. Surface area and density were both highest when 100 terephthaloyl chloride was used but a combination of 5 solid concentration, 100 terephthaloyl chloride and n of 20 gave the best combination of properties.

Compositions and sorptive properties of crop residue-derived chars

USGS Publications Warehouse

Chun, Y.; Sheng, G.; Chiou, G.T.; Xing, B.

2004-01-01

Chars originating from the burning or pyrolysis of vegetation may significantly sorb neutral organic contaminants (NOCs). To evaluate the relationship between the char composition and NOC sorption, a series of char samples were generated by pyrolyzing a wheat residue (Triticum aestivum L) for 6 h at temperatures between 300 ??C and 700 ??C and analyzed for their elemental compositions, surface areas, and surface functional groups. The samples were then studied for their abilities to sorb benzene and nitrobenzene from water. A commercial activated carbon was used as a reference carbonaceous sample. The char samples produced at high pyrolytic temperatures (500-700 ??C) were well carbonized and exhibited a relatively high surface area (>300 m2/g), little organic matter (20% oxygen). The char samples exhibited a significant range of surface acidity/basicity because of their different surface polar-group contents, as characterized by the Boehm titration data and the NMR and FTIR spectra. The NOC sorption by high-temperature chars occurred almost exclusively by surface adsorption on carbonized surfaces, whereas the sorption by low-temperature chars resulted from the surface adsorption and the concurrent smaller partition into the residual organic-matter phase. The chars appeared to have a higher surface affinity for a polar solute (nitrobenzene) than for a nonpolar solute (benzene), the difference being related to the surface acidity/basicity of the char samples.

GIS based 3D visualization of subsurface and surface lineaments / faults and their geological significance, northern tamil nadu, India

NASA Astrophysics Data System (ADS)

Saravanavel, J.; Ramasamy, S. M.

2014-11-01

The study area falls in the southern part of the Indian Peninsular comprising hard crystalline rocks of Archaeozoic and Proterozoic Era. In the present study, the GIS based 3D visualizations of gravity, magnetic, resistivity and topographic datasets were made and therefrom the basement lineaments, shallow subsurface lineaments and surface lineaments/faults were interpreted. These lineaments were classified as category-1 i.e. exclusively surface lineaments, category-2 i.e. surface lineaments having connectivity with shallow subsurface lineaments and category-3 i.e. surface lineaments having connectivity with shallow subsurface lineaments and basement lineaments. These three classified lineaments were analyzed in conjunction with known mineral occurrences and historical seismicity of the study area in GIS environment. The study revealed that the category-3 NNE-SSW to NE-SW lineaments have greater control over the mineral occurrences and the N-S, NNE-SSW and NE-SW, faults/lineaments control the seismicities in the study area.

Digital image processing techniques for detecting surface alteration - An application on the Alaska Peninsula: A section in The United States Geological Survey in Alaska: Accomplishments during 1983

USGS Publications Warehouse

York, James; Wilson, Frederic H.; Gamble, Bruce M.

1985-01-01

The tectonic evolution of the Alaska Peninsula makes it a likely area for the discovery of significant mineral deposits. However, because of problems associated with remoteness and poor weather, little detailed mineral exploration work has been carried on there. This study focuses on using Landsat multispectral scanner data for the Port Moller, Stepovak Bay, and Simeon of Island Quadrangles to detect surface alteration, probably limonitic (iron oxide staining) and(or) argillic (secondary clay minerals) in character, that could be indicative of mineral deposits. The techniques used here are useful for mapping deposits that have exposed surface alteration of at least an hectare, the approximate spatial resolution of the Landsat data. Virtually cloud-free Landsat coverage was used, but to be detected, the alteration area must also be unobscured by vegetation. Not all mineral deposits will be associated with surface alteration, and not all areas of surface alteration will have valuable mineral deposits.

Registration area and accuracy when integrating laser-scanned and maxillofacial cone-beam computed tomography images.

PubMed

Sun, LiJun; Hwang, Hyeon-Shik; Lee, Kyung-Min

2018-03-01

The purpose of this study was to examine changes in registration accuracy after including occlusal surface and incisal edge areas in addition to the buccal surface when integrating laser-scanned and maxillofacial cone-beam computed tomography (CBCT) dental images. CBCT scans and maxillary dental casts were obtained from 30 patients. Three methods were used to integrate the images: R1, only the buccal and labial surfaces were used; R2, the incisal edges of the anterior teeth and the buccal and distal marginal ridges of the second molars were used; and R3, labial surfaces, including incisal edges of anterior teeth, and buccal surfaces, including buccal and distal marginal ridges of the second molars, were used. Differences between the 2 images were evaluated by color-mapping methods and average surface distances by measuring the 3-dimensional Euclidean distances between the surface points on the 2 images. The R1 method showed more discrepancies between the laser-scanned and CBCT images than did the other methods. The R2 method did not show a significant difference in registration accuracy compared with the R3 method. The results of this study indicate that accuracy when integrating laser-scanned dental images into maxillofacial CBCT images can be increased by including occlusal surface and incisal edge areas as registration areas. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Morphological changes in diseased cementum layers: a scanning electron microscopy study.

PubMed

Bilgin, E; Gürgan, C A; Arpak, M Nejat; Bostanci, H S; Güven, K

2004-05-01

The aim of this study was to compare the morphological changes that occurred in root cementum layers due to periodontal disease by using scanning electron microscopy (SEM). Ninety-two periodontally hopeless teeth extracted from 29 patients were studied. Measurements of probing depth (PD) and clinical attachment loss (CAL) were taken prior to extractions. After the longitudinal fracturing process of root specimens, healthy and diseased cementum layers of roots were evaluated by SEM for the thickness of the cementum and the morphological changes in collagen fibers. The result of SEM evaluation revealed a significant ( P < 0.001) decrease in the thickness of cementum layer on the diseased root surfaces compared to the healthy surfaces. There were denser and conspicuous collagen fibers with their interfibrillar matrix in cementum layers on the healthy root surfaces compared to the diseased surfaces. Within the limits of this study, the thickness of cementum layers in diseased areas was found to be significantly less than that in the healthy areas of root surfaces. However, there exist variations in the density and visibility of cemental fibers between individuals and within the individual.

Serial Surgical Debridement of Common Pressure Injuries in the Nursing Home Setting: Outcomes and Findings.

PubMed

Anvar, Bardia; Okonkwo, Henry

2017-07-01

This study examined the efficacy of bedside surgical debridement in a nursing home population. A retrospective chart review was performed of sacrum, sacrococcyx, coccyx, ischium, and trochanter (SSCIT) region pressure injuries in the Skilled Wound Care practice (Los Angeles, CA). The patient population was refined from 2128 to 227 patients visited 8 or more times during nursing home stays found to have 1 or more SSCIT pressure injuries. Of the 227 patients, there were approximately 319 individual SSCIT wounds, with an average of 1.4 SSCIT wounds per patient. Bedside surgical debridement was performed using a sharp excisional technique on 190 of 319 (59.5%) SSCIT wounds. An analysis of the square surface area of the 190 debrided wound sites revealed a mean ulcer surface area of 20.76 cm2. Of those 190 wound sites, 138 (73%) had a reduction in square surface area, and 52 (27%) had no change or an increase in square surface area and were categorized as nonresponders. Of the wounds that did improve by a reduction in wound surface area, the average wound surface area reduction was 6.81 cm2 at 4 weeks (25%), 8.91 cm2 reduction at 8 weeks (33%), and 10.87 cm2 reduction at 12 weeks (40%). From the 190 wound sites, there were a total of 43 (23%) wounds that had a square surface area of 0 (reepithelialized), which has a healing rate of 23%. Traditional bedside debridement provides excellent results in reducing the square surface area for a majority of wounds. Whether used alone or as an adjunct to any treatment plan, the use of surgical sharp equipment aids in achieving good wound healing and advancing the rate of wound closure. Although wound healing requires many components, sharp debridement can effectively remove devitalized tissue and is a proven significant component to advancing wound closure.

Impact of pulsed xenon ultraviolet disinfection on surface contamination in a hospital facility's expressed human milk feed preparation area.

PubMed

Dippenaar, Ricky; Smith, Johan

2018-02-23

Expressed human milk (EHM) feed preparation areas represent a potential source of unintentional nosocomial infection. Daily disinfection of environmental surfaces remains an essential intervention to mitigate nosocomial infections. The inefficiency of conventional cleaning and disinfection contributes to an increased risk for the acquisition of multi-drug resistant pathogens. "Non touch" technologies such as the pulsed xenon ultraviolet (PX-UVD) light device have documented sustained reduction in surface bacterial colonization and reduced cross contamination. The impact of a PX-UVD on surface colony forming units per square centimeter (cfu/cm 2 ) in feed preparation areas was evaluated following its implementation as standard care. A quasi-experimental study was performed documenting bacterial colonization from 6 high risk feed preparation areas in a community care hospital in South Africa. Pre and post conventional cleaning neutralizing rinse swabs were collected fortnightly over a 16 week control period prior to the introduction of the PX-UVD and compared to a matching set of samples for the PX-UVD period. A 90% reduction in total surface bioburden was noted from the control period (544 cfu/cm 2 ) compared to the corresponding PX-UVD period (50 cfu/cm 2 ). Sub -analysis of both the Pre-clean Control: Pre-clean PX-UVD counts as well as the Post-clean Control: Post-clean PX-UVD counts noted significant improvements (p < 0.001). A statistically significant improvement was noted between pre-and post-cleaning total surface bioburden following exposure to the PX-UVD (p = 0.0004). The introduction of the PX-UVD was associated with a sustained reduction in the pre clean bioburden counts with a risk trend (per week) 0.19, (95% CI [0.056, 0.67], p = 0.01). The use of a PX-UVD as adjunct to standard cleaning protocols was associated with a significant decrease in surface bioburden. The study demonstrated the inefficiency of conventional cleaning. Persistence of potentially pathological species in both periods highlights current health sector challenges.

The effects of trawling on the properties of surface sediments in the Lagoon of Venice, Italy.

NASA Astrophysics Data System (ADS)

Aspden, R.; Vardy, S.; Perkins, R.; Davidson, I.; Paterson, D. M.

2003-04-01

The effects of trawling for clams in two differently impacted areas of the Lagoon of Venice were investigated. The Lagoon has an area of 55,000 hectares and the trawling of clams (Tapes phippinarum) has important socio-economic and environmental implications for the area. Bottom trawling has been shown to have large disruptive effects on the structure of benthic communities but the relationship of this to the stability and structure of the surface sediments is still unclear. The sediment stability, grain size, bulk and colloidal carbohydrate content, total organic carbon, chlorophyll a content, and sediment dry bulk density were measured in order to determine the effects of dredging on the physical and biological properties of the lagoon surface sediments. The sediments were more stable at the less impacted site and biological measurements from the same site indicated a relatively low capacity for biogenic stabilisation of sediments. Measurements were taken before and after trawling had occurred. At the less impacted site all biological properties were significantly different before and after the disturbance event, the only physical property to be significantly different was water content. At the highly impacted site the disturbance event had only a small effect on the biological and physical properties of the sediments. Only chlorophyll a content was significantly different before and after the trawl. The results suggest that frequent trawling of the lagoon will reduce the stability of the surface sediments due to the effects on the bulk strength of the sediments and on the biological status of the surface sediments.

Investigation of Aerosol Surface Area Estimation from Number and Mass Concentration Measurements: Particle Density Effect

PubMed Central

Ku, Bon Ki; Evans, Douglas E.

2015-01-01

For nanoparticles with nonspherical morphologies, e.g., open agglomerates or fibrous particles, it is expected that the actual density of agglomerates may be significantly different from the bulk material density. It is further expected that using the material density may upset the relationship between surface area and mass when a method for estimating aerosol surface area from number and mass concentrations (referred to as “Maynard’s estimation method”) is used. Therefore, it is necessary to quantitatively investigate how much the Maynard’s estimation method depends on particle morphology and density. In this study, aerosol surface area estimated from number and mass concentration measurements was evaluated and compared with values from two reference methods: a method proposed by Lall and Friedlander for agglomerates and a mobility based method for compact nonspherical particles using well-defined polydisperse aerosols with known particle densities. Polydisperse silver aerosol particles were generated by an aerosol generation facility. Generated aerosols had a range of morphologies, count median diameters (CMD) between 25 and 50 nm, and geometric standard deviations (GSD) between 1.5 and 1.8. The surface area estimates from number and mass concentration measurements correlated well with the two reference values when gravimetric mass was used. The aerosol surface area estimates from the Maynard’s estimation method were comparable to the reference method for all particle morphologies within the surface area ratios of 3.31 and 0.19 for assumed GSDs 1.5 and 1.8, respectively, when the bulk material density of silver was used. The difference between the Maynard’s estimation method and surface area measured by the reference method for fractal-like agglomerates decreased from 79% to 23% when the measured effective particle density was used, while the difference for nearly spherical particles decreased from 30% to 24%. The results indicate that the use of particle density of agglomerates improves the accuracy of the Maynard’s estimation method and that an effective density should be taken into account, when known, when estimating aerosol surface area of nonspherical aerosol such as open agglomerates and fibrous particles. PMID:26526560

Investigation of Aerosol Surface Area Estimation from Number and Mass Concentration Measurements: Particle Density Effect.

PubMed

Ku, Bon Ki; Evans, Douglas E

2012-04-01

For nanoparticles with nonspherical morphologies, e.g., open agglomerates or fibrous particles, it is expected that the actual density of agglomerates may be significantly different from the bulk material density. It is further expected that using the material density may upset the relationship between surface area and mass when a method for estimating aerosol surface area from number and mass concentrations (referred to as "Maynard's estimation method") is used. Therefore, it is necessary to quantitatively investigate how much the Maynard's estimation method depends on particle morphology and density. In this study, aerosol surface area estimated from number and mass concentration measurements was evaluated and compared with values from two reference methods: a method proposed by Lall and Friedlander for agglomerates and a mobility based method for compact nonspherical particles using well-defined polydisperse aerosols with known particle densities. Polydisperse silver aerosol particles were generated by an aerosol generation facility. Generated aerosols had a range of morphologies, count median diameters (CMD) between 25 and 50 nm, and geometric standard deviations (GSD) between 1.5 and 1.8. The surface area estimates from number and mass concentration measurements correlated well with the two reference values when gravimetric mass was used. The aerosol surface area estimates from the Maynard's estimation method were comparable to the reference method for all particle morphologies within the surface area ratios of 3.31 and 0.19 for assumed GSDs 1.5 and 1.8, respectively, when the bulk material density of silver was used. The difference between the Maynard's estimation method and surface area measured by the reference method for fractal-like agglomerates decreased from 79% to 23% when the measured effective particle density was used, while the difference for nearly spherical particles decreased from 30% to 24%. The results indicate that the use of particle density of agglomerates improves the accuracy of the Maynard's estimation method and that an effective density should be taken into account, when known, when estimating aerosol surface area of nonspherical aerosol such as open agglomerates and fibrous particles.

Growth of contact area between rough surfaces under normal stress

NASA Astrophysics Data System (ADS)

Stesky, R. M.; Hannan, S. S.

1987-05-01

The contact area between deforming rough surfaces in marble, alabaster, and quartz was measured from thin sections of surfaces bonded under load with low viscosity resin epoxy. The marble and alabaster samples had contact areas that increased with stress at an accelerating rate. This result suggests that the strength of the asperity contacts decreased progressively during the deformation, following some form of strain weakening relationship. This conclusion is supported by petrographic observation of the thin sections that indicate that much of the deformation was cataclastic, with minor twinning of calcite and kinking of gypsum. In the case of the quartz, the observed contact area was small and increased approximately linearly with normal stress. Only the irreversible cataclastic deformation was observed; however strain-induced birefringence and cracking of the epoxy, not observed with the other rocks, suggests that significant elastic deformation occurred, but recovered during unloading.

The potential of biomonitoring of air quality using leaf characteristics of white willow (Salix alba L.).

PubMed

Wuytack, Tatiana; Verheyen, Kris; Wuyts, Karen; Kardel, Fatemeh; Adriaenssens, Sandy; Samson, Roeland

2010-12-01

In this study, we assess the potential of white willow (Salix alba L.) as bioindicator for monitoring of air quality. Therefore, shoot biomass, specific leaf area, stomatal density, stomatal pore surface, and stomatal resistance were assessed from leaves of stem cuttings. The stem cuttings were introduced in two regions in Belgium with a relatively high and a relatively low level of air pollution, i.e., Antwerp city and Zoersel, respectively. In each of these regions, nine sampling points were selected. At each sampling point, three stem cuttings of white willow were planted in potting soil. Shoot biomass and specific leaf area were not significantly different between Antwerp city and Zoersel. Microclimatic differences between the sampling points may have been more important to plant growth than differences in air quality. However, stomatal pore surface and stomatal resistance of white willow were significantly different between Zoersel and Antwerp city. Stomatal pore surface was 20% lower in Antwerp city due to a significant reduction in both stomatal length (-11%) and stomatal width (-14%). Stomatal resistance at the adaxial leaf surface was 17% higher in Antwerp city because of the reduction in stomatal pore surface. Based on these results, we conclude that stomatal characteristics of white willow are potentially useful indicators for air quality.

Hemocompatibility Assessment of Carbonic Anhydrase Modified Hollow Fiber Membranes for Artificial Lungs

PubMed Central

Oh, Heung-Il; Ye, Sang-Ho; Johnson, Carl A.; Woolley, Joshua R.; Federspiel, William J.; Wagner, William R.

2011-01-01

Hollow fiber membrane (HFM)-based artificial lungs can require a large blood-contacting membrane surface area to provide adequate gas exchange. However, such a large surface area presents significant challenges to hemocompatibility. One method to improve carbon dioxide (CO2) transfer efficiency might be to immobilize carbonic anhydrase (CA) onto the surface of conventional HFMs. By catalyzing the dehydration of bicarbonate in blood, CA has been shown to facilitate diffusion of CO2 toward the fiber membranes. This study evaluated the impact of surface modifying a commercially available microporous HFM-based artificial lung on fiber blood biocompatibility. A commercial poly(propylene) Celgard HFM surface was coated with a siloxane, grafted with amine groups, and then attached with CA which has been shown to facilitate diffusion of CO2 toward the fiber membranes. Results following acute ovine blood contact indicated no significant reduction in platelet deposition or activation with the siloxane coating or the siloxane coating with grafted amines relative to base HFMs. However,HFMs with attached CA showed a significant reduction in both platelet deposition and activation compared with all other fiber types. These findings, along with the improved CO2 transfer observed in CA modified fibers, suggest that its incorporation into HFM design may potentiate the design of a smaller, more biocompatible HFM-based artificial lung. PMID:20633159

Prediction of phenotypes of missense mutations in human proteins from biological assemblies.

PubMed

Wei, Qiong; Xu, Qifang; Dunbrack, Roland L

2013-02-01

Single nucleotide polymorphisms (SNPs) are the most frequent variation in the human genome. Nonsynonymous SNPs that lead to missense mutations can be neutral or deleterious, and several computational methods have been presented that predict the phenotype of human missense mutations. These methods use sequence-based and structure-based features in various combinations, relying on different statistical distributions of these features for deleterious and neutral mutations. One structure-based feature that has not been studied significantly is the accessible surface area within biologically relevant oligomeric assemblies. These assemblies are different from the crystallographic asymmetric unit for more than half of X-ray crystal structures. We find that mutations in the core of proteins or in the interfaces in biological assemblies are significantly more likely to be disease-associated than those on the surface of the biological assemblies. For structures with more than one protein in the biological assembly (whether the same sequence or different), we find the accessible surface area from biological assemblies provides a statistically significant improvement in prediction over the accessible surface area of monomers from protein crystal structures (P = 6e-5). When adding this information to sequence-based features such as the difference between wildtype and mutant position-specific profile scores, the improvement from biological assemblies is statistically significant but much smaller (P = 0.018). Combining this information with sequence-based features in a support vector machine leads to 82% accuracy on a balanced dataset of 50% disease-associated mutations from SwissVar and 50% neutral mutations from human/primate sequence differences in orthologous proteins. Copyright © 2012 Wiley Periodicals, Inc.

Geospatial analysis of spaceborne remote sensing data for assessing disaster impacts and modeling surface runoff in the built-environment

NASA Astrophysics Data System (ADS)

Wodajo, Bikila Teklu

Every year, coastal disasters such as hurricanes and floods claim hundreds of lives and severely damage homes, businesses, and lifeline infrastructure. This research was motivated by the 2005 Hurricane Katrina disaster, which devastated the Mississippi and Louisiana Gulf Coast. The primary objective was to develop a geospatial decision-support system for extracting built-up surfaces and estimating disaster impacts using spaceborne remote sensing satellite imagery. Pre-Katrina 1-m Ikonos imagery of a 5km x 10km area of Gulfport, Mississippi, was used as source data to develop the built-up area and natural surfaces or BANS classification methodology. Autocorrelation of 0.6 or higher values related to spectral reflectance values of groundtruth pixels were used to select spectral bands and establish the BANS decision criteria of unique ranges of reflectance values. Surface classification results using GeoMedia Pro geospatial analysis for Gulfport sample areas, based on BANS criteria and manually drawn polygons, were within +/-7% of the groundtruth. The difference between the BANS results and the groundtruth was statistically not significant. BANS is a significant improvement over other supervised classification methods, which showed only 50% correctly classified pixels. The storm debris and erosion estimation or SDE methodology was developed from analysis of pre- and post-Katrina surface classification results of Gulfport samples. The SDE severity level criteria considered hurricane and flood damages and vulnerability of inhabited built-environment. A linear regression model, with +0.93 Pearson R-value, was developed for predicting SDE as a function of pre-disaster percent built-up area. SDE predictions for Gulfport sample areas, used for validation, were within +/-4% of calculated values. The damage cost model considered maintenance, rehabilitation and reconstruction costs related to infrastructure damage and community impacts of Hurricane Katrina. The developed models were implemented for a study area along I-10 considering the predominantly flood-induced damages in New Orleans. The BANS methodology was calibrated for 0.6-m QuickBird2 multispectral imagery of Karachi Port area in Pakistan. The results were accurate within +/-6% of the groundtruth. Due to its computational simplicity, the unit hydrograph method is recommended for geospatial visualization of surface runoff in the built-environment using BANS surface classification maps and elevations data. Key words. geospatial analysis, satellite imagery, built-environment, hurricane, disaster impacts, runoff.

Comparative analyses of measured evapotranspiration for various land surfaces

Treesearch

Suat Irmak

2016-01-01

There is a significant lack of continuously measured ET data for multiple land surfaces in the same area to be able to make comparisons of water use rates of different agroecosystems. This research presentation will provide continuous evapotranspiration and other surface energy balance variables measured above multiple land use and management practices.

Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations

USGS Publications Warehouse

Hay, M.B.; Stoliker, D.L.; Davis, J.A.; Zachara, J.M.

2011-01-01

Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ???1% of the solid volume and intragranular surface areas of ???20%-35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity. Copyright 2011 by the American Geophysical Union.

Characterization of the intragranular water regime within subsurface sediments: pore volume, surface area, and mass transfer limitations

USGS Publications Warehouse

Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.

2011-01-01

Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ~1% of the solid volume and intragranular surface areas of ~20%–35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.

Roughness topographical effects on mean momentum and stress budgets in developed turbulent channel flows

NASA Astrophysics Data System (ADS)

Aghaei Jouybari, Mostafa; Yuan, Junlin

2017-11-01

Direct numerical simulations of turbulent channel flows are carried out over two surfaces: a synthesized sand-grain surface and a realistic turbine roughness that is characterized by more prominent large-scale surface features. To separate the effects of wall-normal variation of the roughness area fraction from the (true) variation of flow statistics, the governing equations are area-averaged using intrinsic averaging, contrary to the usually practice based on the total area (i.e., superficial averaging). Additional terms appear in the mean-momentum equation resulted from the wall-normal variation of the solid fraction and play a role in the near-wall balance. Results from surfaces with a step solidity function (e.g., cubes) will also be discussed. Compared to the sand grains, the turbine surface generates stronger form-induced fluctuations, despite weaker dispersive shear stress. This is associated with more significant form-induced productions (comparable to shear production) in Reynolds stress budgets, weaker pressure work, and, consequently, more anisotropic redistribution of turbulent kinetic energy in the roughness sublayer, which potentially leads to different turbulent responses between the two surfaces in non-equilibrium flows.

Use of Several Thermal Analysis Techniques to Study the Cracking of a Nitrile Butadiene Rubber (NBR) Insulator on the Booster Separation Motor (BSM) of the Space Shuttle

NASA Technical Reports Server (NTRS)

Wingard, Charles D.

1999-01-01

Two different vendor rubber formulations have been used to produce the silica-filled NBR insulators for the BSM of each of the two Solid Rocket Boosters (SRBs) on the Space Shuttle. Each cured insulator is bonded to the BSM aluminum aft closure with an epoxy adhesive, and some of the curved areas in the rubber may have significant residual stresses. A number of recently bonded NBR insulators have shown fine surface cracks, and stressed insulator areas may be aging at a faster rate than unstressed areas, thus hastening the surface cracking. Thermal analysis data on both vendor insulators by Dynamic Mechanical Analysis (DMA) through a temperature/frequency sweep from 24 to 74 C have shown a higher flexural storage modulus and Arrhenius activation energy for the stressed area than for the unstressed area. Other thermal analysis techniques are being used to study the insulator surface vs. bulk interior for better understanding this anomaly.

Ikh Turgen Mountain Glacier Change and 3d Surface Extents Prediction Using Long Term Landsat Image and Climate Data

NASA Astrophysics Data System (ADS)

Nasanbat, Elbegjargal; Erdenebat, Erdenetogtokh; Chogsom, Bolorchuluun; Lkhamjav, Ochirkhuyag; Nanzad, Lkhagvadorj

2018-04-01

The glacier is most important the freshwater resources and indicator of the climate change. The researchers noted that during last decades the glacier is melting due to global warming. The study calculates a spatial distribution of protentional change of glacier coverage in the Ikh Turgen mountain of Western Mongolia, and it integrates long-term climate data and satellite datasets. Therefore, in this experiment has tried to estimation three-dimensional surface area of the glacier. For this purpose, Normalized difference snow index (NDSI) was applied to decision tree approach, using Landsat MSS, TM, ETM+ and LC8 imagery for 1975-2016, a surface and slope for digital elevation model, precipitation and air temperature historical data of meteorological station. The potential volume area significantly changed glacier cover of the Ikh Turgen Mountain, and the area affected by highly variable precipitation and air temperature regimes. Between 1972 and 2016, a potential area of glacier area has been decreased in Ikh Turgen mountain region.

Micro-computed tomography evaluation of the preparation of long oval root canals in mandibular molars with the self-adjusting file.

PubMed

Paqué, Frank; Peters, Ove A

2011-04-01

The aim of this study was to assess the shaping potential of a novel nickel-titanium instrument, the self-adjusting file (SAF), in long oval root canals in distal roots in mandibular molars. Twenty mandibular molars with long oval distal root canals were selected and scanned preoperatively and postoperatively by using micro-computed tomography at an original resolution of 20 μm. Canals were shaped with the SAF, three-dimensionally reconstructed, and evaluated for volume, surface area, canal transportation, and prepared surface. Data were statistically contrasted by using paired t tests and regression analysis. Preoperatively, canal volume was 7.73 ± 2.13 mm(3), and canal area was 42.83 ± 8.14 mm(2). Volumes and surface areas increased significantly (P < .001) by 4.84 ± 1.73 mm(3) and 3.34 ± 1.73 mm(2), respectively, and no gross preparation errors were detected. Unprepared canal surface varied between individual canals, and mean unprepared surface was 23.5% ± 8.9%. Prepared areas were significantly larger compared with rotary canal preparation done in a previous study. Canal transportation scores were higher in the coronal root canal third (106 ± 50 μm) compared with the apical third (81 ± 49 μm). In vitro, preparation of long oval-shaped root canals in mandibular molars with the SAF was effective and safe. Moreover, shapes generated with the SAF were more complete compared with rotary canal preparation. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Surges of outlet glaciers from the Drangajökull ice cap, northwest Iceland

NASA Astrophysics Data System (ADS)

Brynjólfsson, Skafti; Schomacker, Anders; Korsgaard, Niels J.; Ingólfsson, Ólafur

2016-09-01

Surface elevation and volume changes of the Drangajökull surge-type glaciers, Reykjarfjarðarjökull and Leirufjarðarjökull, were studied by comparing digital elevation models that pre-date and post-date their most recent surges. Annual glacier-frontal measurements were used to estimate average ice velocities during the last surge of the glaciers. The observations show a distinct ice discharge, most of which was from the upper reservoir areas, down to the receiving areas during the surges. The surface draw-down in the reservoir areas was usually 10-30 m during the surges, while the thickening of the receiving areas was significantly more variable, on the order of 10-120 m. Despite a negative geodetic net mass balance derived from the digital elevation models, the reservoir areas have been gaining mass since the surge terminations. This surface thickening along with considerable ablation of the receiving areas will most likely return the glacier surface profiles to the pre-surge stage. Our results indicate that (a) greatest surface thinning in the upper reservoir areas of Drangajökull rather than proximal to the equilibrium line during Vatnajökull surges and (b) development of Drangajökull surges that resembles Svalbard surge-type glaciers rather than Vatnajökull surge-type glaciers. The contrasting surge characteristics could be explained by differences in glacier geometry, topography and substratum of the Drangajökull and Vatnajökull surge-type glaciers.

Linking morphology with activity through the lifetime of pretreated PtNi nanostructured thin film catalysts

DOE PAGES

Cullen, David A.; Lopez-Haro, Miguel; Bayle-Guillemaud, Pascale; ...

2015-04-10

In this study, the nanoscale morphology of highly active Pt 3Ni 7 nanostructured thin film fuel cell catalysts is linked with catalyst surface area and activity following catalyst pretreatments, conditioning and potential cycling. The significant role of fuel cell conditioning on the structure and composition of these extended surface catalysts is demonstrated by high resolution imaging, elemental mapping and tomography. The dissolution of Ni during fuel cell conditioning leads to highly complex, porous structures which were visualized in 3D by electron tomography. Quantification of the rendered surfaces following catalyst pretreatment, conditioning, and cycling shows the important role pore structure playsmore » in surface area, activity, and durability.« less

The two-phase flow IPTT method for measurement of nonwetting-wetting liquid interfacial areas at higher nonwetting saturations in natural porous media

PubMed Central

Zhong, Hua; Ouni, Asma El; Lin, Dan; Wang, Bingguo; Brusseau, Mark L

2017-01-01

Interfacial areas between nonwetting-wetting (NW-W) liquids in natural porous media were measured using a modified version of the interfacial partitioning tracer test (IPTT) method that employed simultaneous two-phase flow conditions, which allowed measurement at NW saturations higher than trapped residual saturation. Measurements were conducted over a range of saturations for a well-sorted quartz sand under three wetting scenarios of primary drainage (PD), secondary imbibition (SI), and secondary drainage (SD). Limited sets of experiments were also conducted for a model glass-bead medium and for a soil. The measured interfacial areas were compared to interfacial areas measured using the standard IPTT method for liquid-liquid systems, which employs residual NW saturations. In addition, the theoretical maximum interfacial areas estimated from the measured data are compared to specific solid surface areas measured with the N2/BET method and estimated based on geometrical calculations for smooth spheres. Interfacial areas increase linearly with decreasing water saturation over the range of saturations employed. The maximum interfacial areas determined for the glass beads, which have no surface roughness, are 32±4 and 36±5 cm−1 for PD and SI cycles, respectively. The values are similar to the geometric specific solid surface area (31±2 cm−1) and the N2/BET solid surface area (28±2 cm−1). The maximum interfacial areas are 274±38, 235±27, and 581±160 cm−1 for the sand for PD, SI, and SD cycles, respectively, and ~7625 cm−1 for the soil for PD and SI. The maximum interfacial areas for the sand and soil are significantly larger than the estimated smooth-sphere specific solid surface areas (107±8 cm−1 and 152±8 cm−1, respectively), but much smaller than the N2/BET solid surface area (1387±92 cm−1 and 55224 cm−1, respectively). The NW-W interfacial areas measured with the two-phase flow method compare well to values measured using the standard IPTT method. PMID:28959079

Ultrasound-assisted facile synthesis of a new tantalum(V) metal-organic framework nanostructure: Design, characterization, systematic study, and CO2 adsorption performance

NASA Astrophysics Data System (ADS)

Sargazi, Ghasem; Afzali, Daryoush; Mostafavi, Ali; Ebrahimipour, S. Yousef

2017-06-01

This work presents a fast route for the preparation of a new Ta(V) metal-organic framework nanostructure with high surface area, significant porosity, and small size distribution. X-ray diffraction (XRD), scanning electron microscopy (SEM), Transition electron microscopy (TEM), energy dispersive spectrometer (EDS), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), CHNS/O elemental analyser, and Brunauer-Emmett-Teller (BET) surface area analysis were applied to characterize the synthesized product. Moreover, the influences of ultrasonic irradiation including temperature, time, and power on different features of the final products were systematically studied using 2k-1 factorial design experiments, and the response surface optimization was used for determining the best welding parameter combination. The results obtained from analyses of variances showed that ultrasonic parameters affected the size distribution, thermal behaviour, and surface area of Ta-MOF samples. Based on response surface methodology, Ta-MOF could be obtained with mean diameter of 55 nm, thermal stability of 228 °C, and high surface area of 2100 m2/g. The results revealed that the synthesized products could be utilized in various applications such as a novel candidate for CO2 adsorption.

Development of an Operational Land Water Mask for MODIS Collection 6, and Influence on Downstream Data Products

NASA Technical Reports Server (NTRS)

Carroll, M. L.; DiMiceli, C. M.; Townshend, J. R. G.; Sohlberg, R. A.; Elders, A. I.; Devadiga, S.; Sayer, A. M.; Levy, R. C.

2016-01-01

Data from the Moderate Resolution Imaging Spectro-radiometer (MODIS)on-board the Earth Observing System Terra and Aqua satellites are processed using a land water mask to determine when an algorithm no longer needs to be run or when an algorithm needs to follow a different pathway. Entering the fourth reprocessing (Collection 6 (C6)) the MODIS team replaced the 1 km water mask with a 500 m water mask for improved representation of the continental surfaces. The new water mask represents more small water bodies for an overall increase in water surface from 1 to 2 of the continental surface. While this is still a small fraction of the overall global surface area the increase is more dramatic in certain areas such as the Arctic and Boreal regions where there are dramatic increases in water surface area in the new mask. MODIS products generated by the on-going C6 reprocessing using the new land water mask show significant impact in areas with high concentrations of change in the land water mask. Here differences between the Collection 5 (C5) and C6 water masks and the impact of these differences on the MOD04 aerosol product and the MOD11 land surface temperature product are shown.

Hydrological significance of soil frost for pre-alpine areas

NASA Astrophysics Data System (ADS)

Stähli, Manfred

2017-03-01

Soil frost can have a substantial impact on water flows at the soil surface and-potentially-alter the dynamics of catchment runoff. While these findings are mainly based on studies from alpine and Northern-latitude areas (including permafrost areas), little is known about the significance of soil frost for hydrology in pre-alpine areas, i.e. the region at the transition from central European lowlands to high-alpine areas. Here I synthesize soil temperature data and soil frost observations from ten sites in Switzerland to assess the occurrence of soil frost and to determine its impact on catchment runoff. In addition, a well-established numerical model was used to reconstruct the presence of soil frost in two first-order catchments for single runoff events and winters. The data clearly demonstrates that shallow soil frost has formed regularly in this altitudinal range over the past decade. The presence of a frozen soil surface was found to be highly variable among the sites under study and did not significantly correlate with altitude or forest density. For the first-order catchments, it was not possible to relate important flood peaks or increased runoff coefficients to winter situations with substantial soil frost. Thus, the present analysis suggests that although soil frost is widespread and regularly occurring at this altitudinal range, it has no significant impact on winter runoff in pre-alpine watersheds.

A reexamination of the effects of adsorbates on the Raman spectrum of gibbsite.

USGS Publications Warehouse

Cunningham, K.W.; Goldberg, M.C.

1983-01-01

Previous workers have attributed substantial changes in the Raman intensities of the OH stretching bands in solid, powdered gibbsite of surface area 10 m2/g to surface interactions with the adsorbates 093Ca2+,HxPO43x- and SiO2.xH2O. These changes apparently resulted from an unsatisfactory Raman measurement procedure as a re-examination using an internal intensity standard (Na2C2O4 crystals) with gibbsite of surface area 39 m2/g showed no significant changes in the low-frequency band-height ratios of gibbsite and adsorbates.-D.J.M.

Flight Deck Display Technologies for 4DT and Surface Equivalent Visual Operations

NASA Technical Reports Server (NTRS)

Prinzel, Lawrence J., III; Jones, Denis R.; Shelton, Kevin J.; Arthur, Jarvis J., III; Bailey, Randall E.; Allamandola, Angela S.; Foyle, David C.; Hooey, Becky L.

2009-01-01

NASA research is focused on flight deck display technologies that may significantly enhance situation awareness, enable new operating concepts, and reduce the potential for incidents/accidents for terminal area and surface operations. The display technologies include surface map, head-up, and head-worn displays; 4DT guidance algorithms; synthetic and enhanced vision technologies; and terminal maneuvering area traffic conflict detection and alerting systems. This work is critical to ensure that the flight deck interface technologies and the role of the human participants can support the full realization of the Next Generation Air Transportation System (NextGen) and its novel operating concepts.

Comparative Perspectives on Recent Trends in Land Surface Dynamics in the Grasslands of North and South America

NASA Astrophysics Data System (ADS)

Henebry, G. M.; Valle De Carvalho E Oliveira, P.; Zheng, B.; de Beurs, K.; Owsley, B.

2015-12-01

In our current era of intensive earth observation the time is ripe to shift away from studies relying on single sensors or single products to the synergistic use of multiple sensors and products at complementary spatial, temporal, and spectral scales. The use of multiple time series can not only reveal hotspots of change in land surface dynamics, but can indicate plausible proximate causes of the changes and suggest their possible consequences. Here we explore recent trends in the land surface dynamics of exemplary semi-arid grasslands in the western hemisphere, including the shortgrass prairie of eastern Colorado and New Mexico, the sandhills prairie of Nebraska, the "savana gramineo-lenhosa" variety of cerrado in central Brazil, and the pampas of Argentina. Observational datasets include (1) NBAR-based vegetation indices, land surface temperature, and evapotranspiration from MODIS, (2) air temperature, water vapor, and vegetation optical depth from AMSR-E and AMSR2, (3) surface air temperature, water vapor, and relative humidity from AIRS, and (4) surface shortwave, longwave, and total net flux from CERES. The spatial resolutions of these nested data include 500 m, 1000 m, 0.05 degree, 25 km, and 1 degree. We apply the nonparametric Seasonal Kendall trend test to each time series independently to identify areas of significant change. We then examine polygons of co-occurrence of significant change in two or more types of products using the surface radiation and energy budgets as guides to interpret the multiple changes. Changes occurring across broad areas are more likely to be of climatic origin; whereas, changes that are abrupt in space and time and of limited area are more likely anthropogenic. Results illustrate the utility of considering multiple remote sensing products as complementary views of land surface dynamics.

Quantification of mitral regurgitation using proximal isovelocity surface area method in dogs.

PubMed

Choi, Hojung; Lee, Kichang; Lee, Heechun; Lee, Youngwon; Chang, Dongwoo; Eom, Kidong; Youn, Hwayoung; Choi, Mincheol; Yoon, Junghee

2004-06-01

The present study was performed to determine the accuracy and reproducibility of calculating the mitral regurgitant orifice area with the proximal isovelocity surface area (PISA) method in dogs with experimental mitral regurgitation and in canine patients with chronic mitral insufficiency and to evaluate the effect of general anesthesia on mitral regurgitation. Eight adult, Beagle dogs for experimental mitral regurgitation and 11 small breed dogs with spontaneous mitral regurgitation were used. In 8 Beagle dogs, mild mitral regurgitation was created by disrupting mitral chordae or leaflets. Effective regurgitant orifice (ERO) area was measured by the PISA method and compared with the measurements simultaneously obtained by quantitative Doppler echocardiography 4 weeks after creation of mitral regurgitation. The same procedure was performed in 11 patients with isolated mitral regurgitation and in 8 Beagle dogs under two different protocols of general anesthesia. ERO and regurgitant stroke volume (RSV) by the PISA method correlated well with values by the quantitative Doppler technique with a small error in experimental dogs (r = 0.914 and r = 0.839) and 11 patients (r = 0.990 and r = 0.996). The isoflurane anesthetic echocardiography demonstrated a significant decrease of RSV, and there was no significant change in fractional shortening (FS), ERO area, LV end-diastolic and LV end-systolic volume. ERO area showed increasing tendency after ketamine-xylazine administration, but not statistically significant. RSV, LV end-systolic and LV end-diastolic volume increased significantly (p < 0.01), whereas FS significantly decreased (p < 0.01). The PISA method is accurate and reproducible in experimental mitral regurgitation model and in a clinical setting. ERO area is considered and preferred as a hemodynamic-nondependent factor than other traditional measurements.

Morphological dependency of cutaneous blood flow and sweating during compensable heat stress when heat-loss requirements are matched across participants.

PubMed

Notley, Sean R; Park, Joonhee; Tagami, Kyoko; Ohnishi, Norikazu; Taylor, Nigel A S

2016-07-01

Human heat loss is thought, in part, to be morphologically related. It was therefore hypothesized that when heat-loss requirements and body temperatures were matched, that the mass-specific surface area alone could significantly explain both cutaneous vascular and sudomotor responses during compensable exercise. These thermoeffector responses were examined in 36 men with widely varying mass-specific surface areas (range, 232.3-292.7 cm(2)/kg), but of similar age, aerobic fitness, and adiposity. Subjects completed two trials under compensable conditions (28.1°C, 36.8% relative humidity), each involving rest (20 min) and steady-state cycling (45 min) at two matched metabolic heat-production rates (light, ∼135 W/m(2); moderate, ∼200 W/m(2)). Following equivalent mean body temperature changes, forearm blood flow and vascular conductance (r = 0.63 and r = 0.65) shared significant, positive associations with the mass-specific surface area during light work (P < 0.05), explaining ∼45% of the vasomotor variation. Conversely, during light and moderate work, whole body sweat rate, as well as local sweat rate and sudomotor sensitivity at three of four measured sites, revealed moderate, negative relationships with the mass-specific surface area (correlation coefficient range -0.37 to -0.73, P < 0.05). Moreover, those relationships could uniquely account for between 10 and 53% of those sweating responses (P < 0.05). Therefore, both thermoeffector responses displayed a significant morphological dependency in the presence of equivalent thermoafferent drive. Indeed, up to half of the interindividual variation in these effector responses could now be explained through morphological differences and the first principles governing heat transfer. Copyright © 2016 the American Physiological Society.

Morphological dependency of cutaneous blood flow and sweating during compensable heat stress when heat-loss requirements are matched across participants

PubMed Central

Notley, Sean R.; Park, Joonhee; Tagami, Kyoko; Ohnishi, Norikazu

2016-01-01

Human heat loss is thought, in part, to be morphologically related. It was therefore hypothesized that when heat-loss requirements and body temperatures were matched, that the mass-specific surface area alone could significantly explain both cutaneous vascular and sudomotor responses during compensable exercise. These thermoeffector responses were examined in 36 men with widely varying mass-specific surface areas (range, 232.3-292.7 cm2/kg), but of similar age, aerobic fitness, and adiposity. Subjects completed two trials under compensable conditions (28.1°C, 36.8% relative humidity), each involving rest (20 min) and steady-state cycling (45 min) at two matched metabolic heat-production rates (light, ∼135 W/m2; moderate, ∼200 W/m2). Following equivalent mean body temperature changes, forearm blood flow and vascular conductance (r = 0.63 and r = 0.65) shared significant, positive associations with the mass-specific surface area during light work (P < 0.05), explaining ∼45% of the vasomotor variation. Conversely, during light and moderate work, whole body sweat rate, as well as local sweat rate and sudomotor sensitivity at three of four measured sites, revealed moderate, negative relationships with the mass-specific surface area (correlation coefficient range −0.37 to −0.73, P < 0.05). Moreover, those relationships could uniquely account for between 10 and 53% of those sweating responses (P < 0.05). Therefore, both thermoeffector responses displayed a significant morphological dependency in the presence of equivalent thermoafferent drive. Indeed, up to half of the interindividual variation in these effector responses could now be explained through morphological differences and the first principles governing heat transfer. PMID:27125845

Mass-produced multi-walled carbon nanotubes as catalyst supports for direct methanol fuel cells.

PubMed

Jang, In Young; Park, Ki Chul; Jung, Yong Chae; Lee, Sun Hyung; Song, Sung Moo; Muramatsu, Hiroyuki; Kim, Yong Jung; Endo, Morinobu

2011-01-01

Commercially mass-produced multi-walled carbon nanotubes, i.e., VGNF (Showa Denko Co.), were applied to support materials for platinum-ruthenium (PtRu) nanoparticles as anode catalysts for direct methanol fuel cells. The original VGNFs are composed of high-crystalline graphitic shells, which hinder the favorable surface deposition of the PtRu nanoparticles that are formed via borohydride reduction. The chemical treatment of VGNFs with potassium hydroxide (KOH), however, enables highly dispersed and dense deposition of PtRu nanoparticles on the VGNF surface. This capability becomes more remarkable depending on the KOH amount. The electrochemical evaluation of the PtRu-deposited VGNF catalysts showed enhanced active surface areas and methanol oxidation, due to the high dispersion and dense deposition of the PtRu nanoparticles. The improvement of the surface deposition states of the PtRu nanoparticles was significantly due to the high surface area and mesorporous surface structure of the KOH-activated VGNFs.

The anterior approach for the fixation of displaced talar neck fractures--a cadaveric study.

PubMed

Mullen, Michael; Pillai, Anand; Fogg, Quentin A; Kumar, C Senthil

2013-01-01

Talar neck fractures are rare and are associated with high complication rates. Adequate surgical exposure is essential in the operative management of these challenging injuries. The anterior approach is an alternative to the more commonly described and utilized anterolateral and anteromedial approaches. The main objective was to compare the surface area of talus visible and quality of exposure via the anterior approach, with the anteromedial and anterolateral approaches. An anterior approach was performed on five fresh frozen cadaveric specimens. The surface area of talus visible was measured using an Immersion Digital Microscribe and analyzed with the Rhinoceros 3D graphics package. Standard anterolateral and anteromedial approaches were performed in the same specimens and areas visible measured using the same method. The talar surface area visible using the anterior approach is significantly greater than that visible using the anterolateral approach or anteromedial, without and with medial malleolar osteotomy, as well as combination approaches. The anterior approach offers excellent visualization in the fixation of displaced talar neck fractures. Greater talar surface area is visible using this approach compared to traditional approaches. Copyright © 2013 Elsevier Ltd. All rights reserved.

Determining Surface Roughness in Urban Areas Using Lidar Data

NASA Technical Reports Server (NTRS)

Holland, Donald

2009-01-01

An automated procedure has been developed to derive relevant factors, which can increase the ability to produce objective, repeatable methods for determining aerodynamic surface roughness. Aerodynamic surface roughness is used for many applications, like atmospheric dispersive models and wind-damage models. For this technique, existing lidar data was used that was originally collected for terrain analysis, and demonstrated that surface roughness values can be automatically derived, and then subsequently utilized in disaster-management and homeland security models. The developed lidar-processing algorithm effectively distinguishes buildings from trees and characterizes their size, density, orientation, and spacing (see figure); all of these variables are parameters that are required to calculate the estimated surface roughness for a specified area. By using this algorithm, aerodynamic surface roughness values in urban areas can then be extracted automatically. The user can also adjust the algorithm for local conditions and lidar characteristics, like summer/winter vegetation and dense/sparse lidar point spacing. Additionally, the user can also survey variations in surface roughness that occurs due to wind direction; for example, during a hurricane, when wind direction can change dramatically, this variable can be extremely significant. In its current state, the algorithm calculates an estimated surface roughness for a square kilometer area; techniques using the lidar data to calculate the surface roughness for a point, whereby only roughness elements that are upstream from the point of interest are used and the wind direction is a vital concern, are being investigated. This technological advancement will improve the reliability and accuracy of models that use and incorporate surface roughness.

Porosity control in nanoporous carbide-derived carbon by oxidation in air and carbon dioxide

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

Osswald, S.; Portet, C.; Gogotsi, Y., E-mail: gogotsi@drexel.ed

2009-07-15

Carbide-derived carbons (CDC) allow a precise control over the pore size through the selection of the carbide precursor and varying of the synthesis conditions. However, their pore volume is limited by the carbide stoichiometry. While activation of carbons derived from various organic precursors has been widely studied, this process may similarly be able to increase the pore volume and specific surface area of CDC. Oxidation of carbide-derived carbon in air and CO{sub 2} at different temperatures and times allows for significant increase in pore volume and specific surface area as well as control over average pore size with subnanometer accuracy.more » The effect of activation and associated changes in the pore volume and surface area on the hydrogen uptake are also discussed. - Graphical abstract: Carbide-derived carbons (CDC) provide great potential for sorption of toxicants and gas storage applications. Activation of CDC in air and CO{sub 2} at different temperatures and times is applied in order to maximize pore volume and specific surface area, and control the average pore size with subnanometer accuracy.« less

Association of common genetic variants in GPCPD1 with scaling of visual cortical surface area in humans.

PubMed

Bakken, Trygve E; Roddey, J Cooper; Djurovic, Srdjan; Akshoomoff, Natacha; Amaral, David G; Bloss, Cinnamon S; Casey, B J; Chang, Linda; Ernst, Thomas M; Gruen, Jeffrey R; Jernigan, Terry L; Kaufmann, Walter E; Kenet, Tal; Kennedy, David N; Kuperman, Joshua M; Murray, Sarah S; Sowell, Elizabeth R; Rimol, Lars M; Mattingsdal, Morten; Melle, Ingrid; Agartz, Ingrid; Andreassen, Ole A; Schork, Nicholas J; Dale, Anders M; Weiner, Michael; Aisen, Paul; Petersen, Ronald; Jack, Clifford R; Jagust, William; Trojanowki, John Q; Toga, Arthur W; Beckett, Laurel; Green, Robert C; Saykin, Andrew J; Morris, John; Liu, Enchi; Montine, Tom; Gamst, Anthony; Thomas, Ronald G; Donohue, Michael; Walter, Sarah; Gessert, Devon; Sather, Tamie; Harvey, Danielle; Kornak, John; Dale, Anders; Bernstein, Matthew; Felmlee, Joel; Fox, Nick; Thompson, Paul; Schuff, Norbert; Alexander, Gene; DeCarli, Charles; Bandy, Dan; Koeppe, Robert A; Foster, Norm; Reiman, Eric M; Chen, Kewei; Mathis, Chet; Cairns, Nigel J; Taylor-Reinwald, Lisa; Trojanowki, J Q; Shaw, Les; Lee, Virginia M Y; Korecka, Magdalena; Crawford, Karen; Neu, Scott; Foroud, Tatiana M; Potkin, Steven; Shen, Li; Kachaturian, Zaven; Frank, Richard; Snyder, Peter J; Molchan, Susan; Kaye, Jeffrey; Quinn, Joseph; Lind, Betty; Dolen, Sara; Schneider, Lon S; Pawluczyk, Sonia; Spann, Bryan M; Brewer, James; Vanderswag, Helen; Heidebrink, Judith L; Lord, Joanne L; Johnson, Kris; Doody, Rachelle S; Villanueva-Meyer, Javier; Chowdhury, Munir; Stern, Yaakov; Honig, Lawrence S; Bell, Karen L; Morris, John C; Ances, Beau; Carroll, Maria; Leon, Sue; Mintun, Mark A; Schneider, Stacy; Marson, Daniel; Griffith, Randall; Clark, David; Grossman, Hillel; Mitsis, Effie; Romirowsky, Aliza; deToledo-Morrell, Leyla; Shah, Raj C; Duara, Ranjan; Varon, Daniel; Roberts, Peggy; Albert, Marilyn; Onyike, Chiadi; Kielb, Stephanie; Rusinek, Henry; de Leon, Mony J; Glodzik, Lidia; De Santi, Susan; Doraiswamy, P Murali; Petrella, Jeffrey R; Coleman, R Edward; Arnold, Steven E; Karlawish, Jason H; Wolk, David; Smith, Charles D; Jicha, Greg; Hardy, Peter; Lopez, Oscar L; Oakley, MaryAnn; Simpson, Donna M; Porsteinsson, Anton P; Goldstein, Bonnie S; Martin, Kim; Makino, Kelly M; Ismail, M Saleem; Brand, Connie; Mulnard, Ruth A; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Womack, Kyle; Mathews, Dana; Quiceno, Mary; Diaz-Arrastia, Ramon; King, Richard; Weiner, Myron; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I; Lah, James J; Cellar, Janet S; Burns, Jeffrey M; Anderson, Heather S; Swerdlow, Russell H; Apostolova, Liana; Lu, Po H; Bartzokis, George; Silverman, Daniel H S; Graff-Radford, Neill R; Parfitt, Francine; Johnson, Heather; Farlow, Martin R; Hake, Ann Marie; Matthews, Brandy R; Herring, Scott; van Dyck, Christopher H; Carson, Richard E; MacAvoy, Martha G; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Stefanovic, Bojana; Caldwell, Curtis; Ging-Yuek; Hsiung, Robin; Feldman, Howard; Mudge, Benita; Assaly, Michele; Kertesz, Andrew; Rogers, John; Trost, Dick; Bernick, Charles; Munic, Donna; Kerwin, Diana; Mesulam, Marek-Marsel; Lipowski, Kristina; Wu, Chuang-Kuo; Johnson, Nancy; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Raymond Scott; Johnson, Kathleen; Reynolds, Brigid; Sperling, Reisa A; Johnson, Keith A; Marshall, Gad; Frey, Meghan; Yesavage, Jerome; Taylor, Joy L; Lane, Barton; Rosen, Allyson; Tinklenberg, Jared; Sabbagh, Marwan; Belden, Christine; Jacobson, Sandra; Kowall, Neil; Killiany, Ronald; Budson, Andrew E; Norbash, Alexander; Johnson, Patricia Lynn; Obisesan, Thomas O; Wolday, Saba; Bwayo, Salome K; Lerner, Alan; Hudson, Leon; Ogrocki, Paula; Fletcher, Evan; Carmichael, Owen; Olichney, John; Kittur, Smita; Borrie, Michael; Lee, T-Y; Bartha, Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M; Potkin, Steven G; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Fleisher, Adam; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Scharre, Douglas W; Kataki, Maria; Zimmerman, Earl A; Celmins, Dzintra; Brown, Alice D; Pearlson, Godfrey D; Blank, Karen; Anderson, Karen; Santulli, Robert B; Schwartz, Eben S; Sink, Kaycee M; Williamson, Jeff D; Garg, Pradeep; Watkins, Franklin; Ott, Brian R; Querfurth, Henry; Tremont, Geoffrey; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J; Miller, Bruce L; Mintzer, Jacobo; Longmire, Crystal Flynn; Spicer, Kenneth; Finger, Elizabether; Rachinsky, Irina; Drost, Dick; Jernigan, Terry; McCabe, Connor; Grant, Ellen; Ernst, Thomas; Kuperman, Josh; Chung, Yoon; Murray, Sarah; Bloss, Cinnamon; Darst, Burcu; Pritchett, Lexi; Saito, Ashley; Amaral, David; DiNino, Mishaela; Eyngorina, Bella; Sowell, Elizabeth; Houston, Suzanne; Soderberg, Lindsay; Kaufmann, Walter; van Zijl, Peter; Rizzo-Busack, Hilda; Javid, Mohsin; Mehta, Natasha; Ruberry, Erika; Powers, Alisa; Rosen, Bruce; Gebhard, Nitzah; Manigan, Holly; Frazier, Jean; Kennedy, David; Yakutis, Lauren; Hill, Michael; Gruen, Jeffrey; Bosson-Heenan, Joan; Carlson, Heatherly

2012-03-06

Visual cortical surface area varies two- to threefold between human individuals, is highly heritable, and has been correlated with visual acuity and visual perception. However, it is still largely unknown what specific genetic and environmental factors contribute to normal variation in the area of visual cortex. To identify SNPs associated with the proportional surface area of visual cortex, we performed a genome-wide association study followed by replication in two independent cohorts. We identified one SNP (rs6116869) that replicated in both cohorts and had genome-wide significant association (P(combined) = 3.2 × 10(-8)). Furthermore, a metaanalysis of imputed SNPs in this genomic region identified a more significantly associated SNP (rs238295; P = 6.5 × 10(-9)) that was in strong linkage disequilibrium with rs6116869. These SNPs are located within 4 kb of the 5' UTR of GPCPD1, glycerophosphocholine phosphodiesterase GDE1 homolog (Saccharomyces cerevisiae), which in humans, is more highly expressed in occipital cortex compared with the remainder of cortex than 99.9% of genes genome-wide. Based on these findings, we conclude that this common genetic variation contributes to the proportional area of human visual cortex. We suggest that identifying genes that contribute to normal cortical architecture provides a first step to understanding genetic mechanisms that underlie visual perception.

Microclimate Evaluation of the Hradec Králové City using HUMIDEX

NASA Astrophysics Data System (ADS)

Rožnovský, Jaroslav; Litschmann, Tomáš; Středová, Hana; Středa, Tomáš; Salaš, Petr; Horká, Marie

2017-09-01

Urban environment differs from the surrounding landscape in terms of the values of meteorological parameters. This is often referred to as the urban heat island (UHI), which in simple terms means higher air temperatures in cities. The cause of these changes lies in the different active surfaces in cities, which subsequently results in a different radiation balance. The higher temperatures, however, also affect the living conditions in the city and during very high temperature periods can have negative effects on the health of the city inhabitants. The results presented in this paper are based on measurements taken over several years at locations near Hradec Králové, which is surrounded by different surface areas. Environment analysis was performed using the Humidex index. The obtained results show that replacing green areas with built-up areas affects temperatures in the city, when air temperatures are very high they significantly increase the discomfort of the inhabitants. Differences in the frequency of discomfort levels are observed especially during periods of high temperatures, at lower temperatures these differences are not significant. Higher frequencies of discomfort are observed at locations with artificial surfaces (asphalt, cobblestones, concrete) and in closed spaces. In contrast, locations with lots of green areas almost always have the value of this index lower or more balanced. The results should therefore be a valid argument for maintaining and extending green areas in cities.

Size-dependent proinflammatory effects of ultrafine polystyrene particles: a role for surface area and oxidative stress in the enhanced activity of ultrafines.

PubMed

Brown, D M; Wilson, M R; MacNee, W; Stone, V; Donaldson, K

2001-09-15

Studies into the effects of ultrafine particles in the lung have shown adverse effects considered to be due in part to the particle size. Air pollution particles (PM(10)) are associated with exacerbations of respiratory disease and deaths from cardiovascular causes in epidemiological studies and the ultrafine fraction of PM(10) has been hypothesized to play an important role. The aim of the present study was to investigate proinflammatory responses to various sizes of polystyrene particles as a simple model of particles of varying size including ultrafine. In the animal model, we demonstrated that there was a significantly greater neutrophil influx into the rat lung after instillation of 64-nm polystyrene particles compared with 202- and 535-nm particles and this was mirrored in other parameters of lung inflammation, such as increased protein and lactate dehydrogenase in bronchoalveolar lavage. When surface area instilled was plotted against inflammation, these two variables were directly proportional and the line passed through zero. This suggests that surface area drives inflammation in the short term and that ultrafine particles cause a greater inflammatory response because of the greater surface area they possess. In vitro, we measured the changes in intracellular calcium concentration in mono mac 6 cells in view of the potential role of calcium as a signaling molecule. Calcium changes after particle exposure may be important in leading to proinflammatory gene expression such as chemokines. We demonstrated that only ultrafine polystyrene particles induced a significant increase in cytosolic calcium ion concentration. Experiments using dichlorofluorescin diacetate demonstrated greater oxidant activity of the ultrafine particles, which may explain their activity in these assays. There were significant increases in IL-8 gene expression in A549 epithelial cells after treatment with the ultrafine particles but not particles of other sizes. These findings suggest that ultrafine particles composed of low-toxicity material such as polystyrene have proinflammatory activity as a consequence of their large surface area. This supports a role for such particles in the adverse health effects of PM(10). Copyright 2001 Academic Press.

[Effect of glutamine on small intestinal repair in weanling rats after chronic diarrhea].

PubMed

Huang, Zu-xiong; Ye, Li-yan; Zheng, Zhi-yong; Chen, Xin-min; Ren, Rong-na; Tong, Guo-yuan

2005-05-01

To investigate the nutrient effect of glutamine on small intestinal repair in weanling rats after chronic diarrhea. Forty 21-day-old wistar rats were randomly divided into five groups (8 in each). Animal model of chronic diarrhea was induced by a lactose enriched diet in the weanling Wistar rat, normal control group was fed with a standard semipurified diet, and after 14 days the rats in both groups were killed to test the establishment of the model. After the establishment of the model, the other groups were fed with the standard semipurified diet to recover for 7 days, and were randomly divided into three groups: non-intervention group, glutamine (Gln)-intervention group and control group. Glutamine concentrations in blood was detected by high-performance liquid chromatography (HPLC). Morphological changes including villus height and villus surface area of the jejunum were measured under a light microscope and electron microscope, expression of proliferating cell nuclear antigen (PCNA) as an index of cell proliferation was observed using immunohistochemical staining and image analysis. The diarrhea rate in model group was 100 percent, average diarrhea index was 1.16 +/- 0.06, but both diarrhea rate and average diarrhea index in control group were 0 (P < 0.01), which affirmed establishment of the model. There was significant decrease of body weight, plasma Gln concentration, villus height, villus surface area and expression of PCNA in non-intervened group compared with the control group (P < 0.01). There was still significant decrease of body weight, villus height and villus surface area in Gln-intervened group compared with control group (P < 0.01), but plasma Gln concentration and expression of PCNA in Gln-intervened group had recovered to normal (P > 0.05). And compared with non-intervened group, except for body weight (P > 0.05), plasma glutamine, villus height, villus surface area and expression of PCNA were all significantly increased in Gln-intervened group. Chronic diarrhea can induce malnutrition and reduce the villus height, villus surface area, expression of PCNA and plasm glutamine concentration. Oral glutamine could improve the proliferation of crypt cell and promote repair of intestinal mucosa after chronic diarrhea.

Surface Heat Balance Analysis of Tainan City on March 6, 2001 Using ASTER and Formosat-2 Data

PubMed Central

Kato, Soushi; Yamaguchi, Yasushi; Liu, Cheng-Chien; Sun, Chen-Yi

2008-01-01

The urban heat island phenomenon occurs as a mixed result of anthropogenic heat discharge, decreased vegetation, and increased artificial impervious surfaces. To clarify the contribution of each factor to the urban heat island, it is necessary to evaluate the surface heat balance. Satellite remote sensing data of Tainan City, Taiwan, obtained from Terra ASTER and Formosat-2 were used to estimate surface heat balance in this study. ASTER data is suitable for analyzing heat balance because of the wide spectral range. We used Formosat-2 multispectral data to classify the land surface, which was used to interpolate some surface parameters for estimating heat fluxes. Because of the high spatial resolution of the Formosat-2 image, more roads, open spaces and small vegetation areas could be distinguished from buildings in urban areas; however, misclassifications of land cover in such areas using ASTER data would overestimate the sensible heat flux. On the other hand, the small vegetated areas detected from the Formosat-2 image slightly increased the estimation of latent heat flux. As a result, the storage heat flux derived from Formosat-2 is higher than that derived from ASTER data in most areas. From these results, we can conclude that the higher resolution land coverage map increases accuracy of the heat balance analysis. Storage heat flux occupies about 60 to 80% of the net radiation in most of the artificial surface areas in spite of their usages. Because of the homogeneity of the building roof materials, there is no contrast between the storage heat flux in business and residential areas. In sparsely vegetated urban areas, more heat is stored and latent heat is smaller than that in the forested suburbs. This result implies that density of vegetation has a significant influence in decreasing temperatures. PMID:27873856

Reducing microbial contamination in storm runoff from high use areas on California coastal dairies.

PubMed

Lewis, D J; Atwill, E R; Lennox, M S; Pereira, M D G; Miller, W A; Conrad, P A; Tate, K W

2009-01-01

High use areas are a fundamental part of California coastal dairies and grazing livestock ranches as feeding areas, nurseries, and sick pens. High stocking densities and daily use in these areas lead to soil surfaces devoid of vegetation and covered in manure, with high potential for manure transport during winter rains to receiving waters regulated for shellfish harvesting and recreation. We characterized the association between California's Mediterranean climate and a series of existing and proposed management practices on fecal coliform bacteria (FCB) transport from high use areas on dairies and ranches. Results from 351 storm runoff samples collected below 35 high-use areas indicate that removal of cattle during winter, locating high use areas on level ground, application of straw and seeding, and vegetative buffer strip implementation were significantly associated with FCB concentration and load reductions. These results complement our findings for reductions of specific pathogens in runoff from these areas. These findings have practical significance because they document surface water quality benefits that the studied management practices provide in application on working farms and ranches. This direction is critical and timely for on-farm management efforts seeking to reduce microbial pollution in runoff and comply with indicator bacteria water quality criteria.

Field evaluation of two commonly used slipmeters.

PubMed

Chang, Wen-Ruey; Cotnam, John P; Matz, Simon

2003-01-01

A variety of slipmeters have been used to assess the slipperiness of floor surfaces. International standards for the operation of slipmeters describe the protocol for a single measurement. These standards usually do not cover some of the critical elements in safety assessment such as methods for the selection of measurement locations and the necessary number of repeated measurements at each location. Furthermore, most of the slipmeters were evaluated in laboratory settings with new floor surfaces and artificial contaminants. Two commonly used slipmeters, the Brungraber Mark II and the English XL, were evaluated at actual worksites in this experiment. Four floor tiles in each of four different work areas in the kitchens of 18 fast food restaurants were selected for repeated measurements with these two slipmeters. The results indicated that sanding of footwear materials has a significant effect on the outcomes of friction measurements, and the tile-to-tile variations in friction in the same areas of restaurants were also mostly statistically significant. Significant local variation in friction among tiles in the same area could potentially increase the chances of slip and fall incidents. Both slipmeters used in this experiment could potentially have problems in the areas with grease, such as grill and fryer areas, since the build-up of grease during repeated strikes could alter the outcome of friction measured.

Effect of non-Newtonian and pulsatile blood flow on mass transport in the human aorta.

PubMed

Liu, Xiao; Fan, Yubo; Deng, Xiaoyan; Zhan, Fan

2011-04-07

To investigate the effects of both non-Newtonian behavior and the pulsation of blood flow on the distributions of luminal surface LDL concentration and oxygen flux along the wall of the human aorta, we numerically compared a non-Newtonian model with the Newtonian one under both steady flow and in vivo pulsatile flow conditions using a human aorta model constructed from MRI images. The results showed that under steady flow conditions, although the shear thinning non-Newtonian nature of blood could elevate wall shear stress (WSS) in most regions of the aorta, especially areas with low WSS, it had little effect on luminal surface LDL concentration (c(w)) in most regions of the aorta. Nevertheless, it could significantly enhance c(w) in areas with high luminal surface LDL concentration through the shear dependent diffusivity of LDLs. For oxygen transport, the shear thinning non-Newtonian nature of blood could slightly reduce oxygen flux in most regions of the aorta, but this effect became much more apparent in areas with already low oxygen flux. The pulsation of blood flow could significantly reduce c(w) and enhance oxygen flux in these disturbed places. In most other regions of the aorta, the oxygen flux was also significantly higher than that for the steady flow simulation. In conclusion, the shear shining non-Newtonian nature of blood has little effect on LDL and oxygen transport in most regions of the aorta, but in the atherogenic-prone areas where luminal surface LDL concentration is high and oxygen flux is low, its effect is apparent. Similar is for the effect of pulsatile flow on the transport of LDLs. But, the pulsation of blood flow can apparently affect oxygen flux in the aorta, especially in areas with low oxygen flux. Copyright © 2011 Elsevier Ltd. All rights reserved.

Topography-Dependent Motion Compensation: Application to UAVSAR Data

NASA Technical Reports Server (NTRS)

Jones, Cathleen E.; Hensley, Scott; Michel, Thierry

2009-01-01

The UAVSAR L-band synthetic aperture radar system has been designed for repeat track interferometry in support of Earth science applications that require high-precision measurements of small surface deformations over timescales from hours to years. Conventional motion compensation algorithms, which are based upon assumptions of a narrow beam and flat terrain, yield unacceptably large errors in areas with even moderate topographic relief, i.e., in most areas of interest. This often limits the ability to achieve sub-centimeter surface change detection over significant portions of an acquired scene. To reduce this source of error in the interferometric phase, we have implemented an advanced motion compensation algorithm that corrects for the scene topography and radar beam width. Here we discuss the algorithm used, its implementation in the UAVSAR data processor, and the improvement in interferometric phase and correlation achieved in areas with significant topographic relief.

Effect of dialyzer geometry on granulocyte and complement activation.

PubMed

Schaefer, R M; Heidland, A; Hörl, W H

1987-01-01

During hemodialysis with cuprophan membranes, the complement system as well as leukocytes become activated. In order to clarify the role of dialyzer geometry, the effect of hollow-fiber versus flat-sheet dialyzers and of different surface areas on C3a generation and leukocyte degranulation was investigated. Plasma levels of leukocyte elastase in complex with alpha 1-proteinase inhibitor were significantly increased after 1 h (+55%) and 3 h (+62%) of hemodialysis with flat-sheet dialyzers as compared to hollow-fiber devices. In addition, plasma levels of lactoferrin, released from the specific granules of leukocytes during activation, were significantly higher (+42%) 3 h after the onset of dialysis treatment with flat-sheet than with hollow-fiber dialyzers. With respect to surface area, larger dialyzers tended to cause more release of leukocyte elastase as compared to dialyzers with smaller surface areas, irrespectively of the configuration of the dialyzer used. On the other hand, activation of the complement system, as measured by the generation of C3a-desarg, did not differ with both types of configurations. The same held true for leukopenia, which was almost identical for hollow-fiber and flat-sheet dialyzers. From these findings two lines of evidence emerge: First, not only the type of membrane material used in a dialyzer may influence its biocompatibility, but the geometry of the extracorporeal device also determines the degree of compatibility. Hence, the extent of leukocyte activation correlated with both configuration of the dialyzer and surface area of the membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Estimating wetland connectivity to streams in the Prairie Pothole Region: An isotopic and remote sensing approach

USGS Publications Warehouse

Brooks, J. R.; Mushet, David M.; Vanderhoof, Melanie; Leibowitz, Scott G.; Neff, Brian; Christensen, J. R.; Rosenberry, Donald O.; Rugh, W. D.; Alexander, L.C.

2018-01-01

Understanding hydrologic connectivity between wetlands and perennial streams is critical to understanding the reliance of stream flow on inputs from wetlands. We used the isotopic evaporation signal in water and remote sensing to examine wetland‐stream hydrologic connectivity within the Pipestem Creek watershed, North Dakota, a watershed dominated by prairie‐pothole wetlands. Pipestem Creek exhibited an evaporated‐water signal that had approximately half the isotopic‐enrichment signal found in most evaporatively enriched prairie‐pothole wetlands. Groundwater adjacent to Pipestem Creek had isotopic values that indicated recharge from winter precipitation and had no significant evaporative enrichment, indicating that enriched surface water did not contribute significantly to groundwater discharging into Pipestem Creek. The estimated surface water area necessary to generate the evaporation signal within Pipestem Creek was highly dynamic, varied primarily with the amount of discharge, and was typically greater than the immediate Pipestem Creek surface water area, indicating that surficial flow from wetlands contributed to stream flow throughout the summer. We propose a dynamic range of spilling thresholds for prairie‐pothole wetlands across the watershed allowing for wetland inputs even during low‐flow periods. Combining Landsat estimates with the isotopic approach allowed determination of potential (Landsat) and actual (isotope) contributing areas in wetland‐dominated systems. This combined approach can give insights into the changes in location and magnitude of surface water and groundwater pathways over time. This approach can be used in other areas where evaporation from wetlands results in a sufficient evaporative isotopic signal.

Surface water areas significantly impacted 2014 dengue outbreaks in Guangzhou, China

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

Tian, Huaiyu; Huang, Shanqian

Dengue transmission in urban areas is strongly influenced by a range of biological and environmental factors, yet the key drivers still need further exploration. To better understand mechanisms of environment–mosquito–urban dengue transmission, we propose an empirical model parameterized and cross-validated from a unique dataset including viral gene sequences, vector dynamics and human dengue cases in Guangzhou, China, together with a 36-year urban environmental change maps investigated by spatiotemporal satellite image fusion. The dengue epidemics in Guangzhou are highly episodic and were not associated with annual rainfall over time. Our results indicate that urban environmental changes, especially variations in surface areamore » covered by water in urban areas, can substantially alter the virus population and dengue transmission. The recent severe dengue outbreaks in Guangzhou may be due to the surge in an artificial lake construction, which could increase infection force between vector (mainly Aedes albopictus) and host when urban water area significantly increased. Impacts of urban environmental change on dengue dynamics may not have been thoroughly investigated in the past studies and more work needs to be done to better understand the consequences of urbanization processes in our changing world. - Highlights: • Urban dengue outbreak is associated with water area in Guangzhou, 1978–2014. • Surface water area can alter population size of dengue virus in urban area. • Urban dengue outbreak is not associated with annual rainfall in Guangzhou. • Spatiotemporal satellite image fusion can investigate urban environmental change. • Urban environmental change could induce virus, vector, and dengue epidemic change.« less

Effect of cold plasma treatment on seedling growth and nutrient absorption of tomato

NASA Astrophysics Data System (ADS)

Jiafeng, JIANG; Jiangang, LI; Yuanhua, DONG

2018-04-01

The effects of cold plasma (CP) treatment on seed germination, seedling growth, root morphology, and nutrient uptake of a tomato were investigated. The results showed that 80 W of CP treatment significantly increased tomato nitrogen (N) and phosphorus (P) absorption by 12.7% and 19.1%, respectively. CP treatment significantly improved the germination potential of tomato seed by 11.1% and the germination rate by 13.8%. Seedling growth characteristics, including total dry weight, root dry weight, root shoot rate, and leaf area, significantly increased after 80 W of CP treatment. Root activity was increased by 15.7% with 80 W of CP treatment, and 12.6% with 100 W of CP treatment. CP treatment (80 W) markedly ameliorated tomato root morphology, and root length, surface area, and volume, which increased 21.3%, 23.6%, and 29.0%, respectively. Our results suggested that CP treatment improved tomato N and P absorption by promoting the accumulation of shoot and root biomass, increasing the leaf area and root activity, and improving the length, surface area, and volume of root growth. Thus, CP treatment could be used in an ameliorative way to improve tomato nutrient absorption.

Thermodynamics of manganese oxides: Sodium, potassium, and calcium birnessite and cryptomelane

PubMed Central

Birkner, Nancy; Navrotsky, Alexandra

2017-01-01

Manganese oxides with layer and tunnel structures occur widely in nature and inspire technological applications. Having variable compositions, these structures often are found as small particles (nanophases). This study explores, using experimental thermochemistry, the role of composition, oxidation state, structure, and surface energy in the their thermodynamic stability. The measured surface energies of cryptomelane, sodium birnessite, potassium birnessite and calcium birnessite are all significantly lower than those of binary manganese oxides (Mn3O4, Mn2O3, and MnO2), consistent with added stabilization of the layer and tunnel structures at the nanoscale. Surface energies generally decrease with decreasing average manganese oxidation state. A stabilizing enthalpy contribution arises from increasing counter-cation content. The formation of cryptomelane from birnessite in contact with aqueous solution is favored by the removal of ions from the layered phase. At large surface area, surface-energy differences make cryptomelane formation thermodynamically less favorable than birnessite formation. In contrast, at small to moderate surface areas, bulk thermodynamics and the energetics of the aqueous phase drive cryptomelane formation from birnessite, perhaps aided by oxidation-state differences. Transformation among birnessite phases of increasing surface area favors compositions with lower surface energy. These quantitative thermodynamic findings explain and support qualitative observations of phase-transformation patterns gathered from natural and synthetic manganese oxides. PMID:28130549

Estimation of Surface Deformation due to Pasni Earthquake Using SAR Interferometry

NASA Astrophysics Data System (ADS)

Ali, M.; Shahzad, M. I.; Nazeer, M.; Kazmi, J. H.

2018-04-01

Earthquake cause ground deformation in sedimented surface areas like Pasni and that is a hazard. Such earthquake induced ground displacements can seriously damage building structures. On 7 February 2017, an earthquake with 6.3 magnitudes strike near to Pasni. We have successfully distinguished widely spread ground displacements for the Pasni earthquake by using InSAR-based analysis with Sentinel-1 satellite C-band data. The maps of surface displacement field resulting from the earthquake are generated. Sentinel-1 Wide Swath data acquired from 9 December 2016 to 28 February 2017 was used to generate displacement map. The interferogram revealed the area of deformation. The comparison map of interferometric vertical displacement in different time period was treated as an evidence of deformation caused by earthquake. Profile graphs of interferogram were created to estimate the vertical displacement range and trend. Pasni lies in strong earthquake magnitude effected area. The major surface deformation areas are divided into different zones based on significance of deformation. The average displacement in Pasni is estimated about 250 mm. Maximum pasni area is uplifted by earthquake and maximum uplifting occurs was about 1200 mm. Some of areas was subsidized like the areas near to shoreline and maximum subsidence was estimated about 1500 mm. Pasni is facing many problems due to increasing sea water intrusion under prevailing climatic change where land deformation due to a strong earthquake can augment its vulnerability.

A Mathematical Model for Pathogen Cross-Contamination Dynamics during the Postharvest Processing of Leafy Greens.

PubMed

Mokhtari, Amir; Oryang, David; Chen, Yuhuan; Pouillot, Regis; Van Doren, Jane

2018-01-08

We developed a probabilistic mathematical model for the postharvest processing of leafy greens focusing on Escherichia coli O157:H7 contamination of fresh-cut romaine lettuce as the case study. Our model can (i) support the investigation of cross-contamination scenarios, and (ii) evaluate and compare different risk mitigation options. We used an agent-based modeling framework to predict the pathogen prevalence and levels in bags of fresh-cut lettuce and quantify spread of E. coli O157:H7 from contaminated lettuce to surface areas of processing equipment. Using an unbalanced factorial design, we were able to propagate combinations of random values assigned to model inputs through different processing steps and ranked statistically significant inputs with respect to their impacts on selected model outputs. Results indicated that whether contamination originated on incoming lettuce heads or on the surface areas of processing equipment, pathogen prevalence among bags of fresh-cut lettuce and batches was most significantly impacted by the level of free chlorine in the flume tank and frequency of replacing the wash water inside the tank. Pathogen levels in bags of fresh-cut lettuce were most significantly influenced by the initial levels of contamination on incoming lettuce heads or surface areas of processing equipment. The influence of surface contamination on pathogen prevalence or levels in fresh-cut bags depended on the location of that surface relative to the flume tank. This study demonstrates that developing a flexible yet mathematically rigorous modeling tool, a "virtual laboratory," can provide valuable insights into the effectiveness of individual and combined risk mitigation options. © 2018 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

A Surface-based Analysis of Language Lateralization and Cortical Asymmetry

PubMed Central

Greve, Douglas N.; Van der Haegen, Lise; Cai, Qing; Stufflebeam, Steven; Sabuncu, Mert R.; Fischl, Bruce; Bysbaert, Marc

2013-01-01

Among brain functions, language is one of the most lateralized. Cortical language areas are also some of the most asymmetrical in the brain. An open question is whether the asymmetry in function is linked to the asymmetry in anatomy. To address this question, we measured anatomical asymmetry in 34 participants shown with fMRI to have language dominance of the left hemisphere (LLD) and 21 participants shown to have atypical right hemisphere dominance (RLD). All participants were healthy and left-handed, and most (80%) were female. Gray matter (GM) volume asymmetry was measured using an automated surface-based technique in both ROIs and exploratory analyses. In the ROI analysis, a significant difference between LLD and RLD was found in the insula. No differences were found in planum temporale (PT), pars opercularis (POp), pars triangularis (PTr), or Heschl’s gyrus (HG). The PT, POp, insula, and HG were all significantly left lateralized in both LLD and RLD participants. Both the positive and negative ROI findings replicate a previous study using manually labeled ROIs in a different cohort [Keller, S. S., Roberts, N., Garcia-Finana, M., Mohammadi, S., Ringelstein, E. B., Knecht, S., et al. Can the language-dominant hemisphere be predicted by brain anatomy? Journal of Cognitive Neuroscience, 23, 2013–2029, 2011]. The exploratory analysis was accomplished using a new surface-based registration that aligns cortical folding patterns across both subject and hemisphere. A small but significant cluster was found in the superior temporal gyrus that overlapped with the PT. A cluster was also found in the ventral occipitotemporal cortex corresponding to the visual word recognition area. The surface-based analysis also makes it possible to disentangle the effects of GM volume, thickness, and surface area while removing the effects of curvature. For both the ROI and exploratory analyses, the difference between LLD and RLD volume laterality was most strongly driven by differences in surface area and not cortical thickness. Overall, there were surprisingly few differences in GM volume asymmetry between LLD and RLD indicating that gross morphometric asymmetry is only subtly related to functional language laterality. PMID:23701459

Role of morphologic characteristics of the uterine septum in the prediction and prevention of abnormal healing outcomes after hysteroscopic metroplasty

PubMed Central

Ludwin, A.; Ludwin, I.; Pityński, K.; Banas, T.; Jach, R.

2014-01-01

STUDY QUESTION Can morphologic measurements (width, length and surface area) of the uterine septum predict healing-dependent abnormal anatomic results [ARs; residual septum (RS) and intrauterine adhesions in other locations (IUA-OLs)] after complete hysteroscopic metroplasty (HM)? SUMMARY ANSWER Significant predictors of ARs are the septal width and, to a lesser extent, septal surface area. WHAT IS KNOWN ALREADY Anatomic results after hysteroscopic metroplasty have very large variation. A RS >1 cm and IUA-OLs can aggravate reproductive outcomes, resulting in the need for reoperation. New criteria for diagnosing a uterine septum according to the European Society of Human Reproduction and Embryology (ESHRE) and European Society for Gynaecological Endoscopy (ESGE) have been suggested (ESHRE-ESGE criteria). Autocross-linked hyaluronic acid gel (autocross-linked polysaccharide) has an antiadhesive effect. STUDY DESIGN, SIZE, DURATION A prospective, observational cohort study was performed with 96 women consecutively enrolled between 2007 and 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS Women who had uterine septum and previous miscarriage or infertility presented for evaluation at a university hospital, private hospital or private medical center were included. Preoperative septal width, length and surface area were determined with three-dimensional sonohysterography. Women were treated by hysteroscopy in a standardized manner with three- or four-dimensional transrectal ultrasound guidance (complete resection). Patients received either no adhesion barrier (49 patients) or adhesion barrier with autocross-linked polysaccharide (47 patients). Anatomic results were assessed with three-dimensional sonohysterography and second-look hysteroscopy. Healing-dependent ARs were reported using both American Society of Reproductive Medicine (ASRM) criterion of RS length >1 cm (ASRM>1 cm criterion) and ESHRE-ESGE criteria. Univariate and multivariate logistic regression were used to identify predictors of RS, IUA-OLs and ARs. MAIN RESULTS AND ROLE OF CHANCE In patients who had no adhesion barrier, ARs were diagnosed in 11 of 49 patients (23%) using the ASRM > 1 cm criterion and in 20 of 49 patients (41%) using the ESHRE-ESGE criteria for RS [odds ratio (OR)ESHRE-ESGE:ASRM, 2.4, P = 0.05]. In the patients who had autocross-linked polysaccharide, ARsASRM > 1 cm were diagnosed in 2 of 47 patients (4%) and ARsESHRE-ESGE in 4 of 47 patients (9%). RSESHRE-ESGE was diagnosed significantly more often than RSASRM > 1 cm 19 of 96 (20%) versus 5 of 96 (5%) in all patients (ORESHRE-ESGE:ASRM > 1 cm = 4.5, P < 0.01). In patients who had no adhesion barrier, logistic regression with ASRM > 1 cm and ESHRE-ESGE criteria showed that the width and surface area were predictors of ARs. Models adjusted by patient group confirmed the significance of width as a predictor of ARsASRM > 1 cm [OR for width, 3.5 (P < 0.01); OR for group, 0.22 (P < 0.01)], width as a predictor of ARsESHRE-ESGE [OR for width, 2.2 (P < 0.01); OR for group, 0.26 (P < 0.01)] and surface area as a predictor of ARsASRM > 1 cm [OR for surface area, 1.5 (P < 0.01)]; OR for group, 0.32 (P < 0.01). In patients who had autocross-linked polysaccharide, these predictors were not significant. Receiver-operating characteristic curves showed cutoff values for ARsASRM > 1 cm (septal width, 3.42 cm; septal surface area, 4.68cm2) and ARsESHRE-ESGE (septal width, 3.42 cm; septal surface area, 3.51cm2). LIMITATIONS AND REASONS FOR CAUTION Patients were enrolled in the adhesion barrier group in a time-dependent, consecutive and non-randomized manner. WIDER IMPLICATIONS OF THE FINDINGS A wide septum and large surface area may be indications for adhesion barrier. The use of autocross-linked polysaccharide reduces the risk of ARs. The ESHRE-ESGE criteria may cause greater frequency of recognition of RS than the ASRM > 1 cm criterion, which could result in more frequent reoperations with use of the ESHRE-ESGE criteria, possibly without any significant effect on reproductive performance. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by Jagiellonian University (grant no. K/ZDS/003821). The authors have no competing interest to declare. PMID:24838703

Comparison of NMR simulations of porous media derived from analytical and voxelized representations.

PubMed

Jin, Guodong; Torres-Verdín, Carlos; Toumelin, Emmanuel

2009-10-01

We develop and compare two formulations of the random-walk method, grain-based and voxel-based, to simulate the nuclear-magnetic-resonance (NMR) response of fluids contained in various models of porous media. The grain-based approach uses a spherical grain pack as input, where the solid surface is analytically defined without an approximation. In the voxel-based approach, the input is a computer-tomography or computer-generated image of reconstructed porous media. Implementation of the two approaches is largely the same, except for the representation of porous media. For comparison, both approaches are applied to various analytical and digitized models of porous media: isolated spherical pore, simple cubic packing of spheres, and random packings of monodisperse and polydisperse spheres. We find that spin magnetization decays much faster in the digitized models than in their analytical counterparts. The difference in decay rate relates to the overestimation of surface area due to the discretization of the sample; it cannot be eliminated even if the voxel size decreases. However, once considering the effect of surface-area increase in the simulation of surface relaxation, good quantitative agreement is found between the two approaches. Different grain or pore shapes entail different rates of increase of surface area, whereupon we emphasize that the value of the "surface-area-corrected" coefficient may not be universal. Using an example of X-ray-CT image of Fontainebleau rock sample, we show that voxel size has a significant effect on the calculated surface area and, therefore, on the numerically simulated magnetization response.

Human body surface area database and estimation formula.

PubMed

Yu, Chi-Yuang; Lin, Ching-Hua; Yang, Yi-Hsueh

2010-08-01

This study established human body surface area (BSA) database and estimation formula based on three-dimensional (3D) scanned data. For each gender, 135 subjects were drawn. The sampling was stratified in five stature heights and three body weights according to a previous survey. The 3D body surface shape was measured using an innovated 3D body scanner and a high resolution hand/foot scanner, the total body surface area (BSA) and segmental body surface area (SBSA) were computed based on the summation of every tiny triangular area of triangular meshes of the scanned surface; and the accuracy of BSA measurement is below 1%. The results of BSA and sixteen SBSAs were tabulated in fifteen strata for the Male, the Female and the Total (two genders combined). The %SBSA data was also used to revise new Lund and Browder Charts. The comparison of BSA shows that the BSA of this study is comparable with the Du Bois and Du Bois' but smaller than that of Tikuisis et al. The difference might be attributed to body size difference between the samples. The comparison of SBSA shows that the differences of SBSA between this study and the Lund and Browder Chart range between 0.00% and 2.30%. A new BSA estimation formula, BSA=71.3989 x H(.7437) x W(.4040), was obtained. An accuracy test showed that this formula has smaller estimation error than that of the Du Bois and Du Bois'; and significantly better than other BSA estimation formulae.

Ultrasound-assisted facile synthesis of a new tantalum(V) metal-organic framework nanostructure: Design, characterization, systematic study, and CO{sub 2} adsorption performance

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

Sargazi, Ghasem, E-mail: g.sargazi@gmail.com; Young Researchers Society, Shahid Bahonar University of Kerman, Kerman, Iran; Afzali, Daryoush, E-mail: daryoush_afzali@yahoo.com

2017-06-15

This work presents a fast route for the preparation of a new Ta(V) metal-organic framework nanostructure with high surface area, significant porosity, and small size distribution. X-ray diffraction (XRD), scanning electron microscopy (SEM), Transition electron microscopy (TEM), energy dispersive spectrometer (EDS), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), CHNS/O elemental analyser, and Brunauer-Emmett-Teller (BET) surface area analysis were applied to characterize the synthesized product. Moreover, the influences of ultrasonic irradiation including temperature, time, and power on different features of the final products were systematically studied using 2{sup k-1} factorial design experiments, and the response surfacemore » optimization was used for determining the best welding parameter combination. The results obtained from analyses of variances showed that ultrasonic parameters affected the size distribution, thermal behaviour, and surface area of Ta-MOF samples. Based on response surface methodology, Ta-MOF could be obtained with mean diameter of 55 nm, thermal stability of 228 °C, and high surface area of 2100 m{sup 2}/g. The results revealed that the synthesized products could be utilized in various applications such as a novel candidate for CO{sub 2} adsorption. - Graphical abstract: A facile route was used for fabrication of a new metal -organic framework based on tantalum nanostructures that have high surface area, considerable porosity, homogenous morphology, and small size distribution.« less

Effects of the morphology of CIPs on microwave absorption behaviors

NASA Astrophysics Data System (ADS)

Woo, Soobin; Yoo, Chan-Sei; Kim, Hwijun; Lee, Mijung; Quevedo-Lopez, Manuel; Choi, Hyunjoo

2017-11-01

Electromagnetic (EM) wave absorption properties are affected by the thickness and surface area of absorbing materials. In this study, a facile ball-milling process was introduced to effectively reduce the diameter and increase the aspect ratio of carbonyl iron powder (CIP), which is one of the most commercially available EM-absorbing materials. The size, aspect ratio, and consequent surface area of CIP were manipulated by controlling the milling parameters to investigate their effects on EM absorption properties. The results indicated that ball-milled CIPs exhibited better EM wave absorption ability when compared with that of pristine CIPs. However, significant differences in minimum reflection loss values were not observed between CIPs with different morphologies and similar specific surface areas. Hence, both fine and flaky CIPs were considered as beneficial for EM wave absorption.[Figure not available: see fulltext.

Heterogeneity of soil surface temperature induced by xerophytic shrub in a revegetated desert ecosystem, northwestern China

NASA Astrophysics Data System (ADS)

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

2013-06-01

Variation characteristics of the soil surface temperature induced by shrub canopy greatly affects the near-surface biological and biochemical processes in desert ecosystems. However, information regarding the effects of shrub upon the heterogeneity of soil surface temperature is scarce. Here we aimed to characterize the effects of shrub ( Caragana korshinskii) canopy on the soil surface temperature heterogeneity at areas under shrub canopy and the neighbouring bare ground. Diurnal variations of soil surface temperature were measured at areas adjacent to the shrub base (ASB), beneath the midcanopy (BMC), and in the bare intershrub spaces (BIS) at the eastern, southern, western and northern aspects of shrub, respectively. Results indicated that diurnal mean soil surface temperature under the C. korshinskii canopy (ASB and BMC) was significantly lower than in the BIS, with the highest in the BIS, followed by the BMC and ASB. The diurnal maximum and diurnal variations of soil surface temperatures under canopy vary strongly with different aspects of shrub with the diurnal variation in solar altitude, which could be used as cues to detect safe sites for under-canopy biota. A significant empirical linear relationship was found between soil surface temperature and solar altitude, suggesting an empirical predicator that solar altitude can serve for soil surface temperature. Lower soil surface temperatures under the canopy than in the bare intershrub spaces imply that shrubs canopy play a role of `cool islands' in the daytime in terms of soil surface temperature during hot summer months in the desert ecosystems characterized by a mosaic of sparse vegetation and bare ground.

Relationship between Surface Urban Heat Island intensity and sensible heat flux retrieved from meteorological parameters observed by road weather stations in urban area

NASA Astrophysics Data System (ADS)

Gawuć, Lech

2017-04-01

Urban Heat Island (UHI) is a direct consequence of altered energy balance in urban areas (Oke 1982). There has been a significant effort put into an understanding of air temperature variability in urban areas and underlying mechanisms (Arnfield 2003, Grimmond 2006, Stewart 2011, Barlow 2014). However, studies that are concerned on surface temperature are less frequent. Therefore, Voogt & Oke (2003) proposed term "Surface Urban Heat Island (SUHI)", which is analogical to UHI and it is defined as a difference in land surface temperature (LST) between urban and rural areas. SUHI is a phenomenon that is not only concerned with high spatial variability, but also with high temporal variability (Weng and Fu 2014). In spite of the fact that satellite remote sensing techniques give a full spatial pattern over a vast area, such measurements are strictly limited to cloudless conditions during a satellite overpass (Sobrino et al., 2012). This significantly reduces the availability and applicability of satellite LST observations, especially over areas and seasons with high cloudiness occurrence. Also, the surface temperature is influenced by synoptic conditions (e.g., wind and humidity) (Gawuc & Struzewska 2016). Hence, utilising single observations is not sufficient to obtain a full image of spatiotemporal variability of urban LST and SUHI intensity (Gawuc & Struzewska 2016). One of the possible solutions would be a utilisation of time-series of LST data, which could be useful to monitor the UHI growth of individual cities and thus, to reveal the impact of urbanisation on local climate (Tran et al., 2006). The relationship between UHI and synoptic conditions have been summarised by Arnfield (2003). However, similar analyses conducted for urban LST and SUHI are lacking. We will present analyses of the relationship between time series of remotely-sensed LST and SUHI intensity and in-situ meteorological observations collected by road weather stations network, namely: road surface kinetic temperature, wind speed, air temperature, soil temperature at a depth of 30 cm, road surface condition, relative humidity. Also, as there are wind speed and temperature observations at different heights available, we will calculate sensible heat flux in order to relate it to the intensity of SUHI.

Grain boundaries at the surface of consolidated MgO nanocrystals and acid-base functionality.

PubMed

Vingurt, Dima; Fuks, David; Landau, Miron V; Vidruk, Roxana; Herskowitz, Moti

2013-09-21

The increase of the surface basicity-acidity of MgO material by factors of 1.8-3.0 due to consolidation of its nanocrystals was demonstrated by the indicator titration. It was shown that the parallel increase of surface acidity and basicity is attributed to the formation of grain boundaries (GB) after MgO aerogel densification. A simple model predicting the increase of surface acidity-basicity of MgO that correlates with the results of direct measurements was proposed. The model is based on the study of the fine atomic structure at GB surface areas in consolidated MgO nanocrystals in the framework of Density Functional Theory. It is found that the displacements of coordinatively unsaturated surface ions near the GB are significant at the distances ~3-4 atomic layers from the geometrical contact plane between nanocrystals. The detailed analysis of atomic positions inside GB demonstrated the coordination deficiency of surface atoms at the GB areas leading to the formation of stretched bonds and to creation of low coordinated surface ions due to splitting of coordination numbers of surface atoms belonging to GB areas. Density of states for electrons shows the existence of additional states in the band gap close to the bottom of the conduction band. The adsorption energy of CO2 molecules atop oxygen atoms exposed at surface GB areas is of the same order of magnitude as that reported for oxygen atoms at crystallographic edges and corners of MgO crystals. It provides additional options for bonding of molecules at the surface of nanocrystalline MgO increasing the adsorption capacity and catalytic activity.

A “re-vitalized” Greenwood and Williamson model of elastic contact between fractal surfaces

NASA Astrophysics Data System (ADS)

Ciavarella, M.; Delfine, V.; Demelio, G.

2006-12-01

Greenwood and Williamson in 1966 (GW) proposed a theory of elastic contact mechanics of rough surfaces which is today the foundation of many theories in tribology (friction, adhesion, thermal and electrical conductance, wear, etc.). However, the theory has periodically received criticisms for the "resolution-dependence" of the asperity features. Greenwood himself has recently concluded that: "The introduction by Greenwood and Williamson in 1966 of the definition of a 'peak' as a point higher than its neighbours on a profile sampled at a finite sampling interval was, in retrospect, a mistake, although it is possible that it was a necessary mistake" [Greenwood and Wu, 2001. Surface roughness and contact: an apology. Meccanica 36 (6), 617-630]. We propose a "discrete" version of the GW model, keeping the approximation of a surface by quadratic functions near summits, where the summit arrangement is found from numerical realizations or real surfaces scans. The contact is then solved either summing the Hertzian relationships, or considering interaction effects to the first-order in a very efficient algorithm. We conduct experiments on Weierstrass-Mandelbrot fractal surfaces, concluding that: the real contact area-load relationship is well captured by the original GW theoretical model, once the correct mean radius is used. The relationship is robust and shows relatively little scatter; the conductance-load relationship is vice versa only approximately given by the original GW theoretical model. Significant deviations from linearity and significant scatter seem to be found, particularly at low fractal dimensions; the load, area and conductance dependences with separation show significant dependence on the actual phase arrangements, and hence significant scatter at large separations. Effect of interaction is seen strongly at low separations, where scatter is minimal. The discrete GW model permits to include these effects, except when the asperity description breaks down. Refinements of the original GW theory using the full random process theory (such as that by Bush Gibson and Thomas, BGT) result only in small improvements with a significant additional complication. However, the BGT relationship between contact area and load at low loads is more accurate than the more recent theory by Persson. The distribution derived from the original GW theory has been obtained, and shown to be closer to the numerical results than that predicted by the Persson model, even if the area error is removed. It is concluded that the original GW theory deserves the general success received so far, since the resolution-dependence of geometrical features is an intrinsic feature of "fractals" but not a problem for the GW theory, when interaction effects are included.

10 CFR 63.302 - Definitions for Subpart L.

Code of Federal Regulations, 2010 CFR

2010-01-01

...; and (5) The lithosphere. Aquifer means a water-bearing underground geological formation, group of formations, or part of a formation (excluding perched water bodies) that can yield a significant amount of ground water to a well or spring. Controlled area means: (1) The surface area, identified by passive...

10 CFR 63.302 - Definitions for Subpart L.

Code of Federal Regulations, 2011 CFR

2011-01-01

...; and (5) The lithosphere. Aquifer means a water-bearing underground geological formation, group of formations, or part of a formation (excluding perched water bodies) that can yield a significant amount of ground water to a well or spring. Controlled area means: (1) The surface area, identified by passive...

[Three-dimensional evaluation of condylar morphology remodeling after orthognathic surgery in mandibular retrognathism by cone-beam computed tomography].

PubMed

Chen, Shuo; Liu, Xiao-jing; Li, Zi-li; Liang, Cheng; Wang, Xiao-xia; Fu, Kai-yuan; Yi, Biao

2015-08-18

To evaluate the effect of orthognathic surgery on condylar morphology changes by comparing three-dimension surface reconstructions of condyles using cone-beam computed tomography (CBCT) data. In the study, 18 patients with mandible retrognathism deformities were included and CBCT data of 36 temporomandibular joints were collected before surgery and 12 months after surgery. Condyles were reconstructed and superimposed pre- and post-operatively to compare the changes of condylar surfaces. One-sample t test and χ2 test were performed for the analysis of three-dimension metric measurement and condylar head remodeling signs. P<0.05 was considered significant. The root-mean-square (RMS) of condylar surface changes before and after the surgery was (0.37±0.11) mm, which was significant statistically (P<0.05). The distribution of condylar remodeling signs showed significant difference (P<0.05). Bone resorption occurred predominantly in the posterior area of condylar head and bone formation occurred mainly in the anterior area. Three-dimension superimposition method based on CBCT data showed that condylar morphology had undergone remodeling after mandibular advancement.

Exceptional oxygen reduction reaction activity and durability of platinum–nickel nanowires through synthesis and post-treatment optimization

DOE PAGES

Alia, Shaun M.; Ngo, Chilan; Shulda, Sarah; ...

2017-04-11

For the first time, extended nanostructured catalysts are demonstrated with both high specific activity (>6000 μA cm Pt –2 at 0.9 V) and high surface areas (>90 m 2 g Pt –1). Platinum–nickel (Pt—Ni) nanowires, synthesized by galvanic displacement, have previously produced surface areas in excess of 90 m 2 g Pt –1, a significant breakthrough in and of itself for extended surface catalysts. Unfortunately, these materials were limited in terms of their specific activity and durability upon exposure to relevant electrochemical test conditions. Through a series of optimized postsynthesis steps, significant improvements were made to the activity (3-fold increasemore » in specific activity), durability (21% mass activity loss reduced to 3%), and Ni leaching (reduced from 7 to 0.3%) of the Pt—Ni nanowires. Finally, these materials show more than a 10-fold improvement in mass activity compared to that of traditional carbon-supported Pt nanoparticle catalysts and offer significant promise as a new class of electrocatalysts in fuel cell applications.« less

Exceptional oxygen reduction reaction activity and durability of platinum–nickel nanowires through synthesis and post-treatment optimization

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

Alia, Shaun M.; Ngo, Chilan; Shulda, Sarah

For the first time, extended nanostructured catalysts are demonstrated with both high specific activity (>6000 μA cm Pt –2 at 0.9 V) and high surface areas (>90 m 2 g Pt –1). Platinum–nickel (Pt—Ni) nanowires, synthesized by galvanic displacement, have previously produced surface areas in excess of 90 m 2 g Pt –1, a significant breakthrough in and of itself for extended surface catalysts. Unfortunately, these materials were limited in terms of their specific activity and durability upon exposure to relevant electrochemical test conditions. Through a series of optimized postsynthesis steps, significant improvements were made to the activity (3-fold increasemore » in specific activity), durability (21% mass activity loss reduced to 3%), and Ni leaching (reduced from 7 to 0.3%) of the Pt—Ni nanowires. Finally, these materials show more than a 10-fold improvement in mass activity compared to that of traditional carbon-supported Pt nanoparticle catalysts and offer significant promise as a new class of electrocatalysts in fuel cell applications.« less

Nutrients in ground water and surface water of the United States; an analysis of data through 1992

USGS Publications Warehouse

Mueller, D.K.; Hamilton, P.A.; Helsel, D.R.; Hitt, K.J.; Ruddy, B.C.

1995-01-01

Historical data on nutrient (nitrogen and phosphorus species) concentrations in ground-and surface-water samples were compiled from 20 study units of the National Water-Quality Assessment (NAWQA) Program and 5 supplemental study areas. The resultant national retrospective data sets contained analyses of about 12,000 Found-water and more than 22,000 surface-water samples. These data were interpreted on regional and national scales by relating the distributions of nutrient concentrations to ancillary data, such as land use, soil characteristics, and hydrogeology, provided by local study-unit personnel. The information provided in this report on environmental factors that affect nutrient concentrations in ground and surface water can be used to identify areas of the Nation where the vulnerability to nutrient contamination is greatest. Nitrate was the nutrient of greatest concern in the historical ground-water data. It is the only nutrient that is regulated by a national drinking-water standard. Nitrate concentrations were significantly different in ground water affected by various land uses. Concentrations in about 16 percent of the samples collected in agricultural areas exceeded the drinking-water standard. However, the standard was exceeded in only about 1 percent of samples collected from public-supply wells. A variety of ancillary factors had significant relations to nitrate concentrations in ground water beneath agricultural areas. Concentrations generally were highest within 100 feet of the land surface. They were also higher in areas where soil and geologic characteristics promoted rapid movement of water to the aquifer. Elevated concentrations commonly occurred in areas underlain by permeable materials, such as carbonate bedrock or unconsolidated sand and gravel, and where soils are generally well drained. In areas where water movement is impeded, denitrification might lead to low concentrations of nitrate in the ground water. Low concentrations were also related to interspersion of pasture and woodland with cropland in agricultural areas. Elevated nitrate concentrations in areas of more homogeneous cropland probably were a result of intensive nitrogen fertilizer application on large tracts of land. Certain regions of the United States seemed more vulnerable to nitrate contamination of ground water in agricultural areas. Regions of greater vulnerability included parts of the Northeast, Midwest, and West Coast. The well-drained soils, typical in these regions, have little capacity to hold water and nutrients; therefore, these soils receive some of the largest applications of fertilizer and irrigation in the Nation. The agricultural land is intensively cultivated for row crops, with little interspersion of pasture and woodland. Nutrient concentrations in surface water also were generally related to land use. Nitrate concentrations were highest in samples from sites downstream from agricultural or urban areas. However, concentrations were not as high as in ground water and rarely exceeded the drinking-water standard. Elevated concentrations of nitrate in surface water of the Northeastern United States might be related to large amounts of atmospheric deposition (acid rain). High concentrations in parts of the Midwest might be related to tile drainage of agricultural fields. Ammonia and phosphorus concentrations were highest downstream from urban areas. These concentrations generally were high enough to warrant concerns about toxicity to fish and accelerated eutrophication. Recent improvements in wastewater treatment have decreased ammonia concentrations downstream from some urban areas, but the result has been an increase in nitrate concentrations. Information on environmental factors that affect water quality is useful to identify drainage basins throughout the Nation with the greatest vulnerability for nutrient contamination and to delineate areas where ground-water or surface-water contamination is most likely to oc

Spatial variation in water loss predicts terrestrial salamander distribution and population dynamics.

PubMed

Peterman, W E; Semlitsch, R D

2014-10-01

Many patterns observed in ecology, such as species richness, life history variation, habitat use, and distribution, have physiological underpinnings. For many ectothermic organisms, temperature relationships shape these patterns, but for terrestrial amphibians, water balance may supersede temperature as the most critical physiologically limiting factor. Many amphibian species have little resistance to water loss, which restricts them to moist microhabitats, and may significantly affect foraging, dispersal, and courtship. Using plaster models as surrogates for terrestrial plethodontid salamanders (Plethodon albagula), we measured water loss under ecologically relevant field conditions to estimate the duration of surface activity time across the landscape. Surface activity time was significantly affected by topography, solar exposure, canopy cover, maximum air temperature, and time since rain. Spatially, surface activity times were highest in ravine habitats and lowest on ridges. Surface activity time was a significant predictor of salamander abundance, as well as a predictor of successful recruitment; the probability of a juvenile salamander occupying an area with high surface activity time was two times greater than an area with limited predicted surface activity. Our results suggest that survival, recruitment, or both are demographic processes that are affected by water loss and the ability of salamanders to be surface-active. Results from our study extend our understanding of plethodontid salamander ecology, emphasize the limitations imposed by their unique physiology, and highlight the importance of water loss to spatial population dynamics. These findings are timely for understanding the effects that fluctuating temperature and moisture conditions predicted for future climates will have on plethodontid salamanders.

Physical and Biological Impacts of Changing Land-Uses and the Environment

NASA Astrophysics Data System (ADS)

English, W. R.; Pike, J. W.; Jolley, L. W.; Goddard, M. A.; Biondi, M. J.; Hur, J. M.; Powell, B. A.; Morse, J. C.

2005-05-01

A goal of the Changing Land Use and the Environment (CLUE) project is to characterize surface water quality impacted by land-use change in the Saluda and Reedy River watersheds of South Carolina. The CLUE project focuses on impacts common to urban development including 1. sedimentation from construction sites, 2. alteration of discharge and channel morphology due to increased impervious surfaces, 3. macroinvertebrate community response to sedimentation and habitat alteration, and 4. microbial contamination. We found that mean streambed particle size was reduced in developing areas. Stream cross-sectional areas enlarged in catchments with high percentages of impervious surfaces. Sedimentation and altered discharge resulted in the benthic macroinvertebrate community showing a general reduction in biotic integrity values and reductions in Plecoptera taxa richness. Fecal coliform levels were higher for both surface water and bottom sediments in and below urbanized areas during base flows. Levels of fecal coliform in samples collected during storm flows were significantly higher than in base flows, and were correlated with high sediment loads.

Round-patterned ZnO nanostructure coated with siloxane-based polymer for nerve agent detection

NASA Astrophysics Data System (ADS)

Choi, Hyun Ji; Lee, Ji Won; Jeong, Dong-Cheol; Ha, Seonggyun; Song, Changsik; Boo, Jin-Hyo

2018-01-01

The alignment of zinc oxide (ZnO) nanostructures is expected to improve device sensitivities due to large surface areas which can be utilized to capture significant quantities of gas particles. In this study, we investigated patterned ZnO nanorods modified with polystyrene monolayers synthesized directly onto a quartz crystal microbalance (QCM) cell to increase the coating surface area of the sensing material. Also, we designed and synthesized a siloxane-based polymer (S1 polymer) as a sensing material. The patterned ZnO nanorods coated with S1 polymers were fabricated and used for the detection of dimethyl methylphosphonate (DMMP). The resonance frequency of QCM was shifted due to the adsorption and desorption of a compound at the surface of the modified electrodes. We have synthesized an S1 polymer that exhibited high sensitivity to DMMP. The patterned ZnO nanorods coated with the polymer also exhibited improved sensitivity due to an enhanced surface area capable of adsorbing more DMMP vapor.

Trace metal pollution assessment in the surface sediments of nearshore area, off Calicut, southwest coast of India.

PubMed

Srinivas, Reji; Shynu, R; Sreeraj, M K; Ramachandran, K K

2017-07-15

Metal concentrations (Al, Cr, Ni, Cu, Zn, and Pb), grain size, and total organic carbon content in 29 surface sediment samples from the nearshore area off Calicut were analyzed to determine their distribution and pollution status. Surface sediments were dominantly silts with low percentage of clay and sand at nearshore and offshore areas. The mean metal concentrations were in the following order: Cr>Ni>Zn>Pb>Cu. The enrichment factor and geo-accumulation index of metals suggest that the surface sediments were not polluted by Zn and moderately polluted by Cu and Ni. By contrast, Cr and Pb showed significant enrichment levels. Results from a multivariate statistical analysis suggested that the spatial enrichment of these heavy metals was related to sediment type. Thus, the sediment distribution and their metal enrichment were mainly controlled by local hydrodynamic conditions that caused the winnowing of fine-grained sediments. Copyright © 2017. Published by Elsevier Ltd.

Surface EMG crosstalk during phasic involuntary muscle activation in the nociceptive withdrawal reflex.

PubMed

Frahm, Ken S; Jensen, Michael B; Farina, Dario; Andersen, Ole K

2012-08-01

The human nociceptive withdrawal reflex is typically assessed using surface electromyography (sEMG). Based on sEMG, the reflex receptive field (RRF) can be mapped. However, EMG crosstalk can cause erroneous results in the RRF determination. Single differential (SD) vs. double differential (DD) surface EMG were evaluated. Different electrode areas and inter-electrode-distances (IED) were evaluated. The reflexes were elicited by electrical stimulation of the sole of the foot. EMG was obtained from both tibialis anterior (TA) and soleus (SOL) using both surface and intramuscular EMG (iEMG). The amount of crosstalk was significantly higher in SD recordings than in DD recordings (P < 0.05). Crosstalk increased when electrode measuring area increased (P < 0.05) and when IED increased (P < 0.05). Reflex detection sensitivity decreases with increasing measuring area and increasing IED. These results stress that for determination of RRF and similar tasks, DD recordings should be applied. Copyright © 2012 Wiley Periodicals, Inc.

Soft-Template Synthesis of Mesoporous Anatase TiO₂ Nanospheres and Its Enhanced Photoactivity.

PubMed

Li, Xiaojia; Zou, Mingming; Wang, Yang

2017-11-10

Highly crystalline mesoporous anatase TiO₂ nanospheres with high surface area (higher than P25 and anatase TiO₂) are prepared by a soft-template method. Despite the high specific surface area, these samples have three times lower equilibrium adsorption (<2%) than Degussa P25. The rate constant of the mesoporous anatase TiO₂ (0.024 min -1 ) reported here is 364% higher than that of P25 (0.0066 min -1 ), for the same catalytic loading. The results of oxidation-extraction photometry using several reactive oxygen species (ROS) scavengers indicated that mesoporous anatase TiO₂ generates more ROS than P25 under UV-light irradiation. This significant improvement in the photocatalytic performance of mesoporous spherical TiO₂ arises from the following synergistic effects in the reported sample: (i) high surface area; (ii) improved crystallinity; (iii) narrow pore wall thicknesses (ensuring the rapid migration of photogenerated carriers to the surface of the material); and (iv) greater ROS generation under UV-light.

Prospective Clinical Trial of Bladder Filling and Three-Dimensional Dosimetry in High-Dose-Rate Vaginal Cuff Brachytherapy

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

Stewart, Alexandra J.; Cormack, Robert A.; Lee, Hang

2008-11-01

Purpose: To investigate the effect of bladder filling on dosimetry and to determine the best bladder dosimetric parameter for vaginal cuff brachytherapy. Methods and Materials: In this prospective clinical trial, a total of 20 women underwent vaginal cylinder high-dose-rate brachytherapy. The bladder was full for Fraction 2 and empty for Fraction 3. Dose-volume histogram and dose-surface histogram values were generated for the bladder, rectum, and urethra. The midline maximal bladder point (MBP) and the midline maximal rectal point were recorded. Paired t tests, Pearson correlations, and regression analyses were performed. Results: The volume and surface area of the irradiated bladdermore » were significantly smaller when the bladder was empty than when full. Of the several dose-volume histogram and dose-surface histogram parameters evaluated, the bladder maximal dose received by 2 cm{sup 3} of tissue, volume of bladder receiving {>=}50% of the dose, volume of bladder receiving {>=}70% of the dose, and surface area of bladder receiving {>=}50% of the dose significantly predicted for the difference between the empty vs. full filling state. The volume of bladder receiving {>=}70% of the dose and the maximal dose received by 2 cm{sup 3} of tissue correlated significantly with the MBP. Bladder filling did not alter the volume or surface area of the rectum irradiated. However, an empty bladder did result in the nearest point of bowel being significantly closer to the vaginal cylinder than when the bladder was full. Conclusions: Patients undergoing vaginal cuff brachytherapy treated with an empty bladder have a lower bladder dose than those treated with a full bladder. The MBP correlated well with the volumetric assessments of bladder dose and provided a noninvasive method for reporting the MBP dose using three-dimensional imaging. The MBP can therefore be used as a surrogate for complex dosimetry in the clinic.« less

Adsorptive Separation and Sequestration of Krypton, I and C14 on Diamond Nanoparticles

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

Ghosh, Tushar; Loyalka, Sudarsha; Prelas, Mark

The objective of this research proposal was to address the separation and sequestration of Kr and I from each other using nano-sized diamond particles and retaining these in diamond until they decay to the background level or can be used as a byproduct. Following removal of Kr and I, an adsorbent will be used to adsorb and store CO2 from the CO2 rich stream. A Field Enhanced Diffusion with Optical Activation (FEDOA-a large scale process that takes advantage of thermal, electrical, and optical activation to enhance the diffusion of an element into diamond structure) was used to load Kr andmore » I on micron or nano sized particles having a larger relative surface area. The diamond particles can be further increased by doping it with boron followed by irradiation in a neutron flux. Previous studies showed that the hydrogen storage capacity could be increased significantly by using boron-doped irradiated diamond particles. Diamond powders were irradiated for a longer time by placing them in a quartz tube. The surface area was measured using a Quantachrome Autosorb system. No significant increase in the surface area was observed. Total surface area was about 1.7 m2/g. This suggests the existence of very minimal pores. Interestingly it showed hysteresis upon desorption. A reason for this may be strong interaction between the surface and the nitrogen molecules. Adsorption runs at higher temperatures did not show any adsorption of krypton on diamond. Use of a GC with HID detector to determine the adsorption capacity from the breakthrough curves was attempted, but experimental difficulties were encountered.« less

On the urban land-surface impact on climate over Central Europe

NASA Astrophysics Data System (ADS)

Huszar, Peter; Halenka, Tomas; Belda, Michal; Zemankova, Katerina; Zak, Michal

2014-05-01

For the purpose of qualifying and quantifying the impact of cities and in general the urban surfaces on climate over central Europe, the surface parameterization in regional climate model RegCM4 has been extended with the Single Layer Urban Canopy Model (SLUCM) for urban and suburban land surface. This can be used both in dynamic scale within BATS scheme and in a more detailed SUBBATS scale to treat the surface processes on a higher resolution subgrid. A set of experiments was performed over the period of 2005-2009 over central Europe, either without considering urban surfaces and with the SLUCM treatment. Results show a statistically significant impact of urbanized surfaces on temperature (up to 1.5 K increase in summer), on the boundary layer height (ZPBL, increases up to 50 m). Urbanization further influences surface wind with a winter decrease up to -0,6 m s-1 and both increases and decreases in summer depending the location with respect to cities and daytime (changes up to 0.3 ms-1). Urban surfaces significantly reduce evaporation and thus the humidity over the surface. This impacts in our simulations the summer precipitation rate showing decrease over cities up to - 2 mm day-1. We further showed, that significant temperature increases are not limited to the urban canopy layer but spawn the whole boundary layer. Above that, a small but statistically significant temperature decrease is modeled. The comparison with observational data showed significant improvement in modeling the monthly surface temperatures in summer and the models better describe the diurnal temperature variation reducing the afternoon and evening bias due to the UHI development, which was not captured by the model if one does not apply the urban parameterization. Sensitivity experiments were carried out as well to quantify the response of the meteorological conditions to changes in the parameters specific to the urban environment such as street width, building height, albedo of the roofs, anthropogenic heat release etc. and showed that the results are rather robust and the choice of the key SLUCM parameters impacts the results only slightly (mainly temperature, ZPBL and wind velocity). Further, the important conclusion is that statistically significant impacts are modeled not only over large urbanized areas (cities), but the influence of cities is evident over remote rural areas as well with minor or without any urban surfaces. We show that this is the result of the combined effect of the distant influence of surrounding cities and the influence of the minor local urban surface coverage.

Locally Resolved Electron Emission Area and Unified View of Field Emission from Ultrananocrystalline Diamond Films

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

Chubenko, Oksana; Baturin, Stanislav S.; Kovi, Kiran K.

One of the common problems in case of field emission from polycrystalline diamond films, which typically have uniform surface morphology, is uncertainty in determining exact location of electron emission sites across the surface. Although several studies have suggested that grain boundaries are the main electron emission source, it is not particularly clear what makes some sites emit more than the others. It is also practically unclear how one could quantify the actual electron emission area and therefore field emission current per unit area. In this paper we study the effect of actual, locally resolved, field emission (FE) area on electronmore » emission characteristics of uniform planar highly conductive nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) field emitters. It was routinely found that field emission from as-grown planar (N)UNCD films is always confined to a counted number of discrete emitting centers across the surface which varied in size and electron emissivity. It was established that the actual FE area critically depends on the applied electric field, as well as that the actual FE area and the overall electron emissivity improve with sp2 fraction present in the film irrespectively of the original substrate roughness and morphology. To quantify the actual FE area and its dependence on the applied electric field, imaging experiments were carried out in a vacuum system in a parallel-plate configuration with a specialty anode phosphor screen. Electron emission micrographs were taken concurrently with I-V characteristics measurements. In addition, a novel automated image processing algorithm was developed to process extensive imaging datasets and calculate emission area per image. By doing so, it was determined that the emitting area was always significantly smaller than the FE cathode surface area. Namely, the actual FE area would change from 5×10-3 % to 1.5 % of the total cathode area with the applied electric field increased. Finally and most importantly, it was shown that when I-E curves as measured in the experiment were normalized by the field-dependent emission area, the resulting j-E curves demonstrated a strong kink and significant deviation from Fowler-Nordheim (FN) law, and eventually saturated at a current density of ~100 mA/cm2 . This value was nearly identical for all (N)UNCD films measured in this study, regardless of the substrate.« less

Diffusion tensor magnetic resonance imaging driven growth modeling for radiotherapy target definition in glioblastoma.

PubMed

Jensen, Morten B; Guldberg, Trine L; Harbøll, Anja; Lukacova, Slávka; Kallehauge, Jesper F

2017-11-01

The clinical target volume (CTV) in radiotherapy is routinely based on gadolinium contrast enhanced T1 weighted (T1w + Gd) and T2 weighted fluid attenuated inversion recovery (T2w FLAIR) magnetic resonance imaging (MRI) sequences which have been shown to over- or underestimate the microscopic tumor cell spread. Gliomas favor spread along the white matter fiber tracts. Tumor growth models incorporating the MRI diffusion tensors (DTI) allow to account more consistently for the glioma growth. The aim of the study was to investigate the potential of a DTI driven growth model to improve target definition in glioblastoma (GBM). Eleven GBM patients were scanned using T1w, T2w FLAIR, T1w + Gd and DTI. The brain was segmented into white matter, gray matter and cerebrospinal fluid. The Fisher-Kolmogorov growth model was used assuming uniform proliferation and a difference in white and gray matter diffusion of a ratio of 10. The tensor directionality was tested using an anisotropy weighting parameter set to zero (γ0) and twenty (γ20). The volumetric comparison was performed using Hausdorff distance, Dice similarity coefficient (DSC) and surface area. The median of the standard CTV (CTVstandard) was 180 cm 3 . The median surface area of CTVstandard was 211 cm 2 . The median surface area of respective CTV γ0 and CTV γ20 significantly increased to 338 and 376 cm 2 , respectively. The Hausdorff distance was greater than zero and significantly increased for both CTV γ0 and CTV γ20 with respective median of 18.7 and 25.2 mm. The DSC for both CTV γ0 and CTV γ20 were significantly below one with respective median of 0.74 and 0.72, which means that 74 and 72% of CTVstandard were included in CTV γ0 and CTV γ20, respectively. DTI driven growth models result in CTVs with a significantly increased surface area, a significantly increased Hausdorff distance and decreased overlap between the standard and model derived volume.

Surface area dependence of calcium isotopic reequilibration in carbonates: Implications for isotopic signatures in the weathering zone

NASA Astrophysics Data System (ADS)

Fernandez, N. M.; Druhan, J. L.; Potrel, A.; Jacobson, A. D.

2016-12-01

The concept of dynamic equilibrium carries the implicit assumption of continued isotopic exchange between a mineral and the surrounding fluid. While this effect has received much attention in the marine paleoproxy literature, it has been relatively overlooked in application to the terrestrial environment. In weathering systems, a potential consequence is that rapid reequilibration may alter or erase isotopic signatures generated during secondary mineral formation. The extent and timescale over which isotopic signatures are reset in these hydrologic systems is unknown. Using reactive transport modeling, we show isotopic reequilibration under conditions reflecting terrestrial hydrologic settings to be significant and dependent on the reactive surface area of the solid. In particular, we suggest that the non-traditional stable isotopes commonly used in application to carbonates (e.g., Ca, Mg, Sr) are sensitive to these effects due to their rapid reaction rates. We aim to characterize the dependence of Ca isotopic reequilibration on surface area during calcite precipitation via batch experiments conducted at ambient temperature over 48-hour time periods. Calcite precipitation was performed in a closed batch reactor utilizing a controlled free-drift method. The batch reactors contained mixed supersaturated solutions of CaCl2 and NaHCO3 at an initial pH of 8.54. Precipitation was initiated by seed inoculation of calcite crystals with two distinct, pre-constrained surface areas. All experiments achieved the same final state of chemical equilibrium, but as expected, the fastest approach to equilibrium occurred for experiments employing calcite seeds with the highest surface area. This implies that differences in equilibrated Ca isotope ratios (δ44/40Ca) should reflect differences in surface area. This prediction is upheld by models of the experiments, indicating a measureable difference in δ44Ca during calcite precipitation where the higher surface area corresponds to lower δ44Ca values and a faster approach to isotopic equilibrium. The dependence of δ44Ca resetting on calcite surface areas has broad ramifications for tracing carbonate weathering in the Critical Zone.

Erosional and depositional history of central Chryse Planitia

NASA Technical Reports Server (NTRS)

Crumpler, L. S.

1992-01-01

This map uses high resolution image data to assess the detailed depositional and erosional history of part of Chryse Planitia. This area is significant to the study of the global geology of Mars because it represents one of only two areas on the martian surface where planetary geologic mapping is assisted with 'ground truth.' In this case the ground truth was provided by Viking Lander 1. Additional questions addressed in this study are concerned with the following: the geologic context of the regional plains surface and the local surface of the Viking Lander 1 site; and the relative influence of volcanic, sedimentary, impact, aeolian, and tectonic processes at the regional and local scales.

Fish Mercury and Surface Water Sulfate Relationships in the Everglades Protection Area

NASA Astrophysics Data System (ADS)

Gabriel, Mark C.; Howard, Nicole; Osborne, Todd Z.

2014-03-01

Few published studies present data on relationships between fish mercury and surface or pore water sulfate concentrations, particularly on an ecosystem-wide basis. Resource managers can use these relationships to identify the sulfate conditions that contain fish with health-concerning total mercury (THg) levels and to evaluate the role of sulfate in methyl-mercury (MeHg) production. In this study, we derived relationships between THg in three fish trophic levels (mosquitofish, sunfish, and age-1 largemouth bass) and surface water sulfate from 1998 to 2009 for multiple stations across the Everglades Protection Area (EPA). Results show the relationship between sulfate and fish THg in each fish type is nonlinear and largely skewed, similar to the relationship between MeHg production and sulfate concentration in peatland sediment pore water identified by other researchers. Peak fish THg levels occurred in ~1 to 12 mg/L sulfate conditions. There was significant variability in the fish THg data, and there were several instances of high-fish THg levels in high-sulfate conditions (>30 mg/L). Health-concerning fish THg levels were present in all surface water sulfate conditions; however, most of these levels occurred in 1-20 mg/L sulfate. The data in this study, including recent studies, show consistent and identifiable areas of high- and low-fish THg across the spectrum of surface water sulfate concentration, therefore, applying an ecosystem-wide sulfur strategy may be an effective management approach as it would significantly reduce MeHg risk in the EPA.

Characterization of metal adsorption variability in a sand and gravel aquifer, Cape Cod, Massachusetts, U.S.A

USGS Publications Warehouse

Fuller, C.C.; Davis, J.A.; Coston, J.A.; Dixon, E.

1996-01-01

Several geochemical properties of an aquifer sediment that control metal-ion adsorption were investigated to determine their potential use as indicators of the spatial variability of metal adsorption. Over the length of a 4.5-m-long core from a sand and gravel aquifer, lead (Pb2+) and zinc (Zn2+) adsorption at constant chemical conditions (pH 5.3) varied by a factor of 2 and 4, respectively. Pb2+ and Zn2+ were adsorbed primarily by Fe- and Al-oxide coatings on quartz-grain surfaces. Per unit surface area, both Pb2+ and Zn2+ adsorption were significantly correlated with the amount of Fe and Al that dissolved from the aquifer material in a partial chemical extraction. The variability in conditional binding constants for Pb2+ and Zn2+ adsorption (log KADS) derived from a simple non-electrostatic surface complexation model were also predicted by extracted Fe and Al normalized to surface area. Because the abundance of Fe- and Al-oxide coatings that dominate adsorption does not vary inversely with grain size by a simple linear relationship, only a weak, negative correlation was found between the spatial variability of Pb2+ adsorption and grain size in this aquifer. The correlation between Zn2+ adsorption and grain size was not significant. Partial chemical extractions combined with surface-area measurements have potential use for estimating metal adsorption variability in other sand and gravel aquifers of negligible carbonate and organic carbon content.

Fish mercury and surface water sulfate relationships in the Everglades Protection Area.

PubMed

Gabriel, Mark C; Howard, Nicole; Osborne, Todd Z

2014-03-01

Few published studies present data on relationships between fish mercury and surface or pore water sulfate concentrations, particularly on an ecosystem-wide basis. Resource managers can use these relationships to identify the sulfate conditions that contain fish with health-concerning total mercury (THg) levels and to evaluate the role of sulfate in methyl-mercury (MeHg) production. In this study, we derived relationships between THg in three fish trophic levels (mosquitofish, sunfish, and age-1 largemouth bass) and surface water sulfate from 1998 to 2009 for multiple stations across the Everglades Protection Area (EPA). Results show the relationship between sulfate and fish THg in each fish type is nonlinear and largely skewed, similar to the relationship between MeHg production and sulfate concentration in peatland sediment pore water identified by other researchers. Peak fish THg levels occurred in ~1 to 12 mg/L sulfate conditions. There was significant variability in the fish THg data, and there were several instances of high-fish THg levels in high-sulfate conditions (>30 mg/L). Health-concerning fish THg levels were present in all surface water sulfate conditions; however, most of these levels occurred in 1-20 mg/L sulfate. The data in this study, including recent studies, show consistent and identifiable areas of high- and low-fish THg across the spectrum of surface water sulfate concentration, therefore, applying an ecosystem-wide sulfur strategy may be an effective management approach as it would significantly reduce MeHg risk in the EPA.

Long-term versus short-term deformation of the meizoseismal area of the 2008 Achaia-Elia (MW 6.4) earthquake in NW Peloponnese, Greece: Evidence from historical triangulation and morphotectonic data

NASA Astrophysics Data System (ADS)

Stiros, Stathis; Moschas, Fanis; Feng, Lujia; Newman, Andrew

2013-04-01

The deformation of the meizoseismal area of the 2008 Achaia-Elia (MW 6.4) earthquake in NW Peloponnese, of the first significant strike slip earthquake in continental Greece, was examined in two time scales; of 102 years, based on the analysis of high-accuracy historical triangulation data describing shear, and of 105-106 years, based on the analysis of the hydrographic network of the area for signs of streams offset by faulting. Our study revealed pre-seismic accumulation of shear strain of the order of 0.2 μrad/year in the study area, consistent with recent GPS evidence, but no signs of significant strike slip-induced offsets in the hydrographic network. These results confirm the hypothesis that the 2008 fault, which did not reached the surface and was not associated with significant seismic ground deformation, probably because of a surface flysch layer filtering high-strain events, was associated with an immature or a dormant, recently activated fault. This fault, about 150 km long and discordant to the morphotectonic trends of the area, seems first, to contain segments which have progressively reactivated in a specific direction in the last 20 years, reminiscent of the North Anatolian Fault, and second, to limit an 150 km wide (recent?) shear zone in the internal part of the arc, in a region mostly dominated by thrust faulting and strong destructive earthquakes. Deformation of the first main strike slip fault in continental Greece analyzed. Triangulation data show preseismic shear, hydrographic net no previous faulting. Surface shear deformation only in low strain rates. Immature or reactivated dormant strike slip fault, with gradual oriented rupturing. Interplay between shear and thrusting along the arc.

Monitoring monthly surface water dynamics of Dongting Lake using Sentinel-1 data at 10 m.

PubMed

Xing, Liwei; Tang, Xinming; Wang, Huabin; Fan, Wenfeng; Wang, Guanghui

2018-01-01

High temporal resolution water distribution maps are essential for surface water monitoring because surface water exhibits significant inner-annual variation. Therefore, high-frequency remote sensing data are needed for surface water mapping. Dongting Lake, the second-largest freshwater lake in China, is famous for the seasonal fluctuations of its inundation extents in the middle reaches of the Yangtze River. It is also greatly affected by the Three Gorges Project. In this study, we used Sentinel-1 data to generate surface water maps of Dongting Lake at 10 m resolution. First, we generated the Sentinel-1 time series backscattering coefficient for VH and VV polarizations at 10 m resolution by using a monthly composition method. Second, we generated the thresholds for mapping surface water at 10 m resolution with monthly frequencies using Sentinel-1 data. Then, we derived the monthly surface water distribution product of Dongting Lake in 2016, and finally, we analyzed the inner-annual surface water dynamics. The results showed that: (1) The thresholds were -21.56 and -15.82 dB for the backscattering coefficients for VH and VV, respectively, and the overall accuracy and Kappa coefficients were above 95.50% and 0.90, respectively, for the VH backscattering coefficient, and above 94.50% and 0.88, respectively, for the VV backscattering coefficient. The VV backscattering coefficient achieved lower accuracy due to the effect of the wind causing roughness on the surface of the water. (2) The maximum and minimum areas of surface water were 2040.33 km 2 in July, and 738.89 km 2 in December. The surface water area of Dongting Lake varied most significantly in April and August. The permanent water acreage in 2016 was 556.35 km 2 , accounting for 19.65% of the total area of Dongting Lake, and the acreage of seasonal water was 1525.21 km 2 . This study proposed a method to automatically generate monthly surface water at 10 m resolution, which may contribute to monitoring surface water in a timely manner.

Cell behavior on surface modified polydimethylsiloxane (PDMS).

PubMed

Stanton, Morgan M; Rankenberg, Johanna M; Park, Byung-Wook; McGimpsey, W Grant; Malcuit, Christopher; Lambert, Christopher R

2014-07-01

Designing complex tissue culture systems requires cell alignment and directed extracellular matrix (ECM) and gene expression. Here, a micro-rough, polydimethylsiloxane (PDMS) surface, that also integrates a micro-pattern of 50 µm wide lines of fibronectin (FN) separated by 60 µm wide lines of bovine serum albumin (BSA), is developed. Human fibroblasts cultured on the rough, patterned substrate have aligned growth and a significant change in morphology when compared to cells on a flat, patterned surface. The rough PDMS topography significantly decreases cell area and induces the upregulation of several ECM related genes by two-fold when compared to cells cultured on flat PDMS. This study describes a simple surface engineering procedure for creating surface architecture for scaffolds to design and control the cell-surface interface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recruitment from an egg bank into the plankton in Baisha Bay, a mariculture base in Southern China

NASA Astrophysics Data System (ADS)

Wang, Qing; Luan, Lei-Lei; Chen, Liang-Dong; Yuan, Dan-Ni; Liu, Sheng; Hwang, Jiang-Shiou; Yang, Yu-Feng

2016-11-01

The potential recruitment of resting eggs of calanoid copepods and rotifers to planktonic populations was investigated in the surface and sub-surface sediments of three mariculture zones: an integrated seaweed Gracilaria lemaneiformis and shellfish cultivation area (G), a fish cultivation area (F), and a shellfish cultivation area (S), as well as the sediments of a nearby control sea area (C) in a mariculture base in Southern China. The potential recruitment of copepod and rotifer eggs in the sediments of C and G was significantly higher than in F and S. Potential recruitment in the sub-surface sediments of F and S was not observed, suggesting that fish and shellfish mariculture may be responsible for this decrease. The hatching success of resting eggs of copepods and rotifers was affected by mariculture type, and that large-scale seaweed cultivation may offset the adverse effect of fish and shellfish cultivation on the resting eggs if integrated cultivation is adopted.

The Effects of Secondary Oxides on Copper-Based Catalysts for Green Methanol Synthesis.

PubMed

Hayward, James S; Smith, Paul J; Kondrat, Simon A; Bowker, Michael; Hutchings, Graham J

2017-05-10

Catalysts for methanol synthesis from CO 2 and H 2 have been produced by two main methods: co-precipitation and supercritical anti-solvent (SAS) precipitation. These two methods are compared, along with the behaviour of copper supported on Zn, Mg, Mn, and Ce oxides. Although the SAS method produces initially active material with high Cu specific surface area, they appear to be unstable during reaction losing significant amounts of surface area and hence activity. The CuZn catalysts prepared by co-precipitation, however, showed much greater thermal and reactive stability than the other materials. There appeared to be the usual near-linear dependence of activity upon Cu specific area, though the initial performance relationship was different from that post-reaction, after some loss of surface area. The formation of the malachite precursor, as reported before, is important for good activity and stability, whereas if copper oxides are formed during the synthesis and ageing process, then a detrimental effect on these properties is seen.

The Effects of Secondary Oxides on Copper‐Based Catalysts for Green Methanol Synthesis

PubMed Central

Hayward, James S.; Smith, Paul J.; Kondrat, Simon A.; Bowker, Michael

2017-01-01

Abstract Catalysts for methanol synthesis from CO2 and H2 have been produced by two main methods: co‐precipitation and supercritical anti‐solvent (SAS) precipitation. These two methods are compared, along with the behaviour of copper supported on Zn, Mg, Mn, and Ce oxides. Although the SAS method produces initially active material with high Cu specific surface area, they appear to be unstable during reaction losing significant amounts of surface area and hence activity. The CuZn catalysts prepared by co‐precipitation, however, showed much greater thermal and reactive stability than the other materials. There appeared to be the usual near‐linear dependence of activity upon Cu specific area, though the initial performance relationship was different from that post‐reaction, after some loss of surface area. The formation of the malachite precursor, as reported before, is important for good activity and stability, whereas if copper oxides are formed during the synthesis and ageing process, then a detrimental effect on these properties is seen. PMID:28706570

Anatomical and morphological study of the subcoracoacromial canal.

PubMed

Le Reun, O; Lebhar, J; Mateos, F; Voisin, J L; Thomazeau, H; Ropars, M

2016-12-01

Many clinical anatomy studies have looked into how variations in the acromion, coracoacromial ligament (CAL) and subacromial space are associated with rotator cuff injuries. However, no study up to now had defined anatomically the fibro-osseous canal that confines the supraspinatus muscle in the subcoracoacromial space. Through an anatomical study of the scapula, we defined the bone-related parameters of this canal and its anatomical variations. This study on dry bones involved 71 scapulas. With standardised photographs in two orthogonal views (superior and lateral), the surface area of the subcoracoacromial canal and the anatomical parameters making up this canal were defined and measured using image analysis software. The primary analysis evaluated the anatomical parameters of the canal as a function of three canal surface area groups; the secondary analysis looked into how variations in the canal surface area were related to the type of acromion according to the Bigliani classification. Relative to glenoid width, the group with a large canal surface area (L) had significantly less lateral overhang of the acromion than the group with a small canal surface area (S), with ratios of 0.41±0.23 and 0.58±0.3, respectively (P=0.04). The mean length of the CAL was 46±8mm in the L group and 39±9mm in the S group (P=0.003). The coracoacromial arch angle was 38°±11° in the L group and 34°±9° in the S group; the canal surface area was smaller in specimens with a smaller coracoacromial arch angle (P=0.20). Apart from acromial morphology, there could be innate anatomical features of the scapula that predispose people to extrinsic lesions to the supraspinatus tendon (lateral overhang, coracoacromial arch angle) by reducing the subcoracoacromial canal's surface area. Anatomical descriptive study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Assessment of Surface Water Storage trends for increasing groundwater areas in India

NASA Astrophysics Data System (ADS)

Banerjee, Chandan; Kumar, D. Nagesh

2018-07-01

Recent studies based on Gravity Recovery and Climate Experiment (GRACE) satellite mission suggested that groundwater has increased in central and southern parts of India. However, surface water, which is an equally important source of water in these semi-arid areas has not been studied yet. In the present study, the study areas were outlined based on trends in GRACE data followed by trend identification in surface water storages and checking the hypothesis of causality. Surface Water Extent (SWE) and Surface Soil Moisture (SSM) derived from Moderate-resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) respectively, are selected as proxies of surface water storage (SWS). Besides SWE and SSM, trend test was performed for GRACE derived terrestrial water storage (TWS) for the study areas named as R1, R2, GOR1 and KOR1. Granger-causality test is used to test the hypothesis that rainfall is a causal factor of the inter-annual variability of SWE, SSM and TWS. Positive trends were observed in TWS for R1, R2 and GOR1 whereas SWE and SSM show increasing trends for all the study regions. Results suggest that rainfall is the granger-causal of all the storage variables for R1 and R2, the regions exhibiting the most significant positive trends in TWS.

Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

NASA Astrophysics Data System (ADS)

So, Hongyun; Senesky, Debbie G.

2016-01-01

In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area.

Surface Water in Hawaii

USGS Publications Warehouse

Oki, Delwyn S.

2003-01-01

Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

Surface and adsorptive properties of Moringa oleifera bark for removal of V(V) from aqueous solutions.

PubMed

Mnisi, Robert Londi; Ndibewu, Peter Papoh

2017-11-04

The bark of Moringa oleifera, a cheap and readily available natural biopolymeric resource material, found to significantly reduce coliform load and turbidity in contaminated water is investigated in this paper. Its surface and adsorptive properties are investigated to explore its adsorptive potential in removing V(V) from aqueous solutions. Surface properties were investigated using FTIR, HRSEM/EDS, IC, and BET-N 2 adsorption techniques. Adsorptive properties were investigated by optimizing adsorption parameters such as pH, temperature, initial metal concentration, and adsorbent dosage, using V(V) as an adsorbate. The adsorption-desorption isotherms are typical of type II with a H3 hysteresis loop and is characteristic of a largely macroporous material. Bottle ink pores are observed, which can provide good accessibility of the active sites, even though the internal BET surface area is typically low (1.79 g/m 2 ). Solution pH significantly influences the adsorptive potential of the material. The low surface area negatively impacts on the adsorption capacity, but is compensated for by the exchangeable anions (Cl - , F - , PO 4 3- , NO 3 - , and SO 4 2- ) and cations (Ca 2+ , K + , Mg 2+ , and Al 3+ ) at the surface and the accessibility of the active sites. Adsorption isotherm modeling show that the surface is largely heterogeneous with complex multiple sites and adsorption is not limited to monolayer.

Surface and Basal Roughness in Radar Sounding Data: Obstacle and Opportunity

NASA Astrophysics Data System (ADS)

Schroeder, D. M.; Grima, C.; Haynes, M.

2015-12-01

The surface and basal roughness of glaciers, ice sheets, and ice shelves can pose a significant obstacle to the visual interpretation and quantitative analysis of radar sounding data. Areas of high surface roughness - including grounding zones, shear margins, and crevasse fields - can produce clutter and side-lobe signals that obscure the interpretation of englacial and subglacial features. These areas can also introduce significant variation in bed echo strength profiles as a result of losses from two-way propagation through rough ice surfaces. Similarly, reflections from rough basal interfaces beneath ice sheets and ice shelves can also result in large, spatially variable losses in bed echo power. If unmitigated and uncorrected, these effects can degrade or prevent the definitive interpretation of material and geometric properties at the base of ice sheets and ice shelves using radar reflectivity and bed echo character. However, these effects also provide geophysical signatures of surface and basal interface character - including surface roughness, firn density, subglacial bedform geometry, ice shelf basal roughness, marine-ice/brine detection, and crevasse geometry - that can be observed and constrained by exploiting roughness effects in radar sounding data. We present a series of applications and approaches for characterizing and correcting surface and basal roughness effects for airborne radar sounding data collected in Antarctica. We also present challenges, insights, and opportunities for extending these techniques to the orbital radar sounding of Europa's ice shell.

Resuscitation burn card--a useful tool for burn injury assessment.

PubMed

Malic, C C; Karoo, R O S; Austin, O; Phipps, A

2007-03-01

It is well recognised that the initial assessment of body surface area affected by a burn is often over estimated in Accident and Emergency Departments. A useful aide-memoir in the acute setting is Wallace's "rule of nines" or using the patients' palmar surface of the hand, which approximates 1% of the total body surface area, as a method of assessment. Unfortunately, as with every system, limitations apply. Factors such as patient size and the interpretation of what is exactly the 'palmar surface' may significantly influence burn size estimations and subsequently fluid resuscitation. Our aim is to develop a simple, quick and easy reproducible method of calculating burn injuries for medical professionals in the acute setting. Worldwide, the dimensions of a credit card are standardized (8.5 cm x 5.3 cm), thus producing a surface area of 45 cm2. We created a resuscitation burn card (RBC) using these exact same proportions, upon which a modified body surface area (BSA) nomogram was printed. Knowing the patient height and weight, we calculated the surface area of the card as percentage of total body surface area (TBSA). On the opposite site of the RBC, a Lund and Browder chart was printed, as well as the Parkland formula and a formula to calculate paediatric burn fluid requirements. The plastic, flexible RBC conformed well to the body contour and was designed for single use. We used the resuscitation burn card in the initial assessment of simulated burns in a Regional Burn Centre and in an Accident and Emergency Department. The information present on the card was found to be clear and straightforward to use. The evaluation of burn extent was found to be more accurately measured than the estimation obtained without the RBC. The resuscitation burn card can be a valuable tool in the hands of less experienced medical professionals for the early assessment and fluid resuscitation of a burn.

Effects of landscape composition and pattern on land surface temperature: An urban heat island study in the megacities of Southeast Asia.

PubMed

Estoque, Ronald C; Murayama, Yuji; Myint, Soe W

2017-01-15

Due to its adverse impacts on urban ecological environment and the overall livability of cities, the urban heat island (UHI) phenomenon has become a major research focus in various interrelated fields, including urban climatology, urban ecology, urban planning, and urban geography. This study sought to examine the relationship between land surface temperature (LST) and the abundance and spatial pattern of impervious surface and green space in the metropolitan areas of Bangkok (Thailand), Jakarta (Indonesia), and Manila (Philippines). Landsat-8 OLI/TIRS data and various geospatial approaches, including urban-rural gradient, multiresolution grid-based, and spatial metrics-based techniques, were used to facilitate the analysis. We found a significant strong correlation between mean LST and the density of impervious surface (positive) and green space (negative) along the urban-rural gradients of the three cities, depicting a typical UHI profile. The correlation of impervious surface density with mean LST tends to increase in larger grids, whereas the correlation of green space density with mean LST tends to increase in smaller grids, indicating a stronger influence of impervious surface and green space on the variability of LST in larger and smaller areas, respectively. The size, shape complexity, and aggregation of the patches of impervious surface and green space also had significant relationships with mean LST, though aggregation had the most consistent strong correlation. On average, the mean LST of impervious surface is about 3°C higher than that of green space, highlighting the important role of green spaces in mitigating UHI effects, an important urban ecosystem service. We recommend that the density and spatial pattern of urban impervious surfaces and green spaces be considered in landscape and urban planning so that urban areas and cities can have healthier and more comfortable living urban environments. Copyright © 2016 Elsevier B.V. All rights reserved.

Long-term stormwater quantity and quality performance of permeable pavement systems.

PubMed

Brattebo, Benjamin O; Booth, Derek B

2003-11-01

This study examined the long-term effectiveness of permeable pavement as an alternative to traditional impervious asphalt pavement in a parking area. Four commercially available permeable pavement systems were evaluated after 6 years of daily parking usage for structural durability, ability to infiltrate precipitation, and impacts on infiltrate water quality. All four permeable pavement systems showed no major signs of wear. Virtually all rainwater infiltrated through the permeable pavements, with almost no surface runoff. The infiltrated water had significantly lower levels of copper and zinc than the direct surface runoff from the asphalt area. Motor oil was detected in 89% of samples from the asphalt runoff but not in any water sample infiltrated through the permeable pavement. Neither lead nor diesel fuel were detected in any sample. Infiltrate measured 5 years earlier displayed significantly higher concentrations of zinc and significantly lower concentrations of copper and lead.

The Contribution of Object Shape and Surface Properties to Object Ensemble Representation in Anterior-medial Ventral Visual Cortex.

PubMed

Cant, Jonathan S; Xu, Yaoda

2017-02-01

Our visual system can extract summary statistics from large collections of objects without forming detailed representations of the individual objects in the ensemble. In a region in ventral visual cortex encompassing the collateral sulcus and the parahippocampal gyrus and overlapping extensively with the scene-selective parahippocampal place area (PPA), we have previously reported fMRI adaptation to object ensembles when ensemble statistics repeated, even when local image features differed across images (e.g., two different images of the same strawberry pile). We additionally showed that this ensemble representation is similar to (but still distinct from) how visual texture patterns are processed in this region and is not explained by appealing to differences in the color of the elements that make up the ensemble. To further explore the nature of ensemble representation in this brain region, here we used PPA as our ROI and investigated in detail how the shape and surface properties (i.e., both texture and color) of the individual objects constituting an ensemble affect the ensemble representation in anterior-medial ventral visual cortex. We photographed object ensembles of stone beads that varied in shape and surface properties. A given ensemble always contained beads of the same shape and surface properties (e.g., an ensemble of star-shaped rose quartz beads). A change to the shape and/or surface properties of all the beads in an ensemble resulted in a significant release from adaptation in PPA compared with conditions in which no ensemble feature changed. In contrast, in the object-sensitive lateral occipital area (LO), we only observed a significant release from adaptation when the shape of the ensemble elements varied, and found no significant results in additional scene-sensitive regions, namely, the retrosplenial complex and occipital place area. Together, these results demonstrate that the shape and surface properties of the individual objects comprising an ensemble both contribute significantly to object ensemble representation in anterior-medial ventral visual cortex and further demonstrate a functional dissociation between object- (LO) and scene-selective (PPA) visual cortical regions and within the broader scene-processing network itself.

Surface Forces Apparatus Measurements of Interactions between Rough and Reactive Calcite Surfaces.

PubMed

Dziadkowiec, Joanna; Javadi, Shaghayegh; Bratvold, Jon E; Nilsen, Ola; Røyne, Anja

2018-06-26

nm-Range forces acting between calcite surfaces in water affect macroscopic properties of carbonate rocks and calcite-based granular materials and are significantly influenced by calcite surface recrystallization. We suggest that the repulsive mechanical effects related to nm-scale surface recrystallization of calcite in water could be partially responsible for the observed decrease of cohesion in calcitic rocks saturated with water. Using the surface forces apparatus, we simultaneously followed the calcite reactivity and measured the forces in water in two surface configurations: between two rough calcite surfaces (CC) and between rough calcite and a smooth mica surface (CM). We used nm-scale rough, polycrystalline calcite films prepared by atomic layer deposition. We measured only repulsive forces in CC in CaCO 3 -saturated water, which was related to roughness and possibly to repulsive hydration effects. Adhesive or repulsive forces were measured in CM in CaCO 3 -saturated water depending on calcite roughness, and the adhesion was likely enhanced by electrostatic effects. The pull-off adhesive force in CM became stronger with time, and this increase was correlated with a decrease of roughness at contacts, the parameter which could be estimated from the measured force-distance curves. That suggested a progressive increase of real contact areas between the surfaces, caused by gradual pressure-driven deformation of calcite surface asperities during repeated loading-unloading cycles. Reactivity of calcite was affected by mass transport across nm- to μm-thick gaps between the surfaces. Major roughening was observed only for the smoothest calcite films, where gaps between two opposing surfaces were nm-thick over μm-sized areas and led to force of crystallization that could overcome confining pressures of the order of MPa. Any substantial roughening of calcite caused a significant increase of the repulsive mechanical force contribution.

Geostatistical Analysis of Surface Temperature and In-Situ Soil Moisture Using LST Time-Series from Modis

NASA Astrophysics Data System (ADS)

Sohrabinia, M.; Rack, W.; Zawar-Reza, P.

2012-07-01

The objective of this analysis is to provide a quantitative estimate of the fluctuations of land surface temperature (LST) with varying near surface soil moisture (SM) on different land-cover (LC) types. The study area is located in the Canterbury Plains in the South Island of New Zealand. Time series of LST from the MODerate resolution Imaging Spectro-radiometer (MODIS) have been analysed statistically to study the relationship between the surface skin temperature and near-surface SM. In-situ measurements of the skin temperature and surface SM with a quasi-experimental design over multiple LC types are used for validation. Correlations between MODIS LST and in-situ SM, as well as in-situ surface temperature and SM are calculated. The in-situ measurements and MODIS data are collected from various LC types. Pearson's r correlation coefficient and linear regression are used to fit the MODIS LST and surface skin temperature with near-surface SM. There was no significant correlation between time-series of MODIS LST and near-surface SM from the initial analysis, however, careful analysis of the data showed significant correlation between the two parameters. Night-time series of the in-situ surface temperature and SM from a 12 hour period over Irrigated-Crop, Mixed-Grass, Forest, Barren and Open- Grass showed inverse correlations of -0.47, -0.68, -0.74, -0.88 and -0.93, respectively. These results indicated that the relationship between near-surface SM and LST in short-terms (12 to 24 hours) is strong, however, remotely sensed LST with higher temporal resolution is required to establish this relationship in such time-scales. This method can be used to study near-surface SM using more frequent LST observations from a geostationary satellite over the study area.

Uptake and bioconcentration of hexachlorobiphenyl by periphyton

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

Sallenave, R.M.; Day, K.E.

1995-12-31

Laboratory experiments were conducted to examine the bioconcentration of 2,2{prime},4,4{prime},5,5{prime} hexachlorobiphenyl (HCBP) in lotic periphyton. The instantaneous rate of uptake and bioconcentration factor (BCF) were determined by following the bioaccumulation of {sup 14}C-HCBP in periphytic communities established on glass slides. The rate of accumulation was highest in the first 3 hours, and equilibrium was reached within eight days. The bioconcentration factor averaged 16,000. The results of a deputation experiment indicated that HCBP desorbed from periphyton, but at a much slower rate than its adsorption. After 28 days of deputation, no significant losses of HCBP in the periphyton had occurred. Nomore » significant relationship existed between concentrations of HCBP and dry weight of periphyton, suggesting the sorption was primarily determined by surface area available, and that increases in periphytic biomass would not necessarily result in corresponding increases in surface area available for partitioning of HCBP. The results of this study suggest that lotic periphyton provide a large surface area for adsorption and uptake of persistent lipophilic compounds such as HCBP, and depending on the extent of grazing pressure, could greatly influence the fate and transport of these compounds in lotic systems.« less

SnO2 Nanostructures: Effect of Processing Parameters on Their Structural and Functional Properties

NASA Astrophysics Data System (ADS)

Dontsova, Tetiana A.; Nagirnyak, Svitlana V.; Zhorov, Vladyslav V.; Yasiievych, Yuriy V.

2017-05-01

Zero- and 1D (one-dimensional) tin (IV) oxide nanostructures have been synthesized by thermal evaporation method, and a comparison of their morphology, crystal structure, sorption properties, specific surface area, as well as electrical characteristics has been performed. Synthesized SnO2 nanomaterials were studied by X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), N2 sorption/desorption technique, IR spectroscopy and, in addition, their current-voltage characteristics have also been measured. The single crystalline structures were obtained both in case of 0D (zero-dimensional) SnO2 powders and in case of 0D nanofibers, as confirmed by electron diffraction of TEM. It was found that SnO2 synthesis parameters significantly affect materials' properties by contributing to the difference in morphology, texture formation, changes in IR spectra of 1D structure as compared to 0D powders, increases in the specific surface area of nanofibers, and the alteration of current-voltage characteristics 0D and 1D SnO2 nanostructures. It was established that gas sensors utilizing of 1D nanofibers significantly outperform those based on 0D powders by providing higher specific surface area and ohmic I-V characteristics.

Hydrologic reconnaissance of the Kolob, Alton, and Kaiparowits Plateau coal fields, south-central Utah

USGS Publications Warehouse

Plantz, Gerald G.

1985-01-01

The study area in south-central Utah (fig. 1) is noted for its large coal reserves in the Alton, Kolob, and Kaiparowits Plateau coal fields. The area also is noted for its scenic beauty and general scarcity of water. Although there has been very little development of the coal resources through 1983, there is a potential for large-scale development with both surface- and underground-mining methods. Mining of coal could have significant effects on the quantity and quality of the water resources. The purpose of this atlas is to define the surface- and ground-water resources of the area and to identify the potential effects on these resources by coal mining.

Determination of airborne nanoparticles from welding operations.

PubMed

Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

2012-01-01

The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers.

Nitrate-nitrogen reduction by established tree and pasture buffer strips associated with a cattle feedlot effluent disposal area near Armidale, NSW Australia.

PubMed

Wang, Liangmin; Duggin, John A; Nie, Daoping

2012-05-30

Vegetated buffer strips have been recognized as an important element in overall agro-ecosystem management to reduce the delivery of non-point source pollutants from agricultural land to inland water systems. A buffer strip experiment consisting of two tree species (Eucalyptus camaldulensis and Casuarina cunninghamiana) with two planting densities and a pasture treatment was conducted to determine the effectiveness of NO(3)-N removal from a cattle feedlot effluent disposal area at Tullimba near Armidale, NSW Australia. Different management methods were applied for the buffers where grass and weeds were mowed 2-3 times during the second and third years and were not managed during the rest experimental years for the tree buffer, while grass was harvested 1-3 times per year for the pasture buffer. The differences between tree species and planting density significantly affected tree growth, but the growth difference did not significantly affect their capacities to reduce NO(3)-N in soil surface runoff and groundwater. On average for all the tree and pasture treatments, the buffer strips reduced NO(3)-N concentration by 8.5%, 14.7% and 14.4% for the surface runoff, shallow and deep groundwater respectively. The tree and pasture buffer strips were not significantly different in NO(3)-N reduction for both shallow and deep groundwater while the pasture buffer strips reduced significantly more NO(3)-N concentration in surface runoff than the tree buffer strips. Both buffer strips reduced more than 50% of surface runoff volume indicating that both the tree and pasture buffer strips were efficient at removing water and nutrients, mostly through a significant reduction in soil surface runoff volume. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extent of Low-accumulation 'Wind Glaze' Areas on the East Antarctic Plateau: Implications for Continental Ice Mass Balance

NASA Technical Reports Server (NTRS)

Scambos, Theodore A.; Frezzotti, Massimo; Haran, T.; Bohlander, J.; Lenaerts, J. T. M.; Van Den Broeke, M. R.; Jezek, K.; Long, D.; Urbini, S.; Farness, K.;

The Morphological Anatomy of the Menisci of the Knee Joint in Human Fetuses

PubMed Central

Koyuncu, Esra; Özgüner, Gülnur; Öztürk, Kenan; Bilkay, Cemil; Dursun, Ahmet; Sulak, Osman

2017-01-01

Background: Development of the foetal period of the meniscus has been reported in different studies. Aims: Evaluation of lateral and medial meniscus development, typing and the relationship of the tibia during the foetal period. Study Design: Anatomical dissection. Methods: We evaluated 210 knee menisci obtained from 105 human foetuses ranging in age from 9 to 40 weeks’ gestation. Foetuses were divided into four groups, and the intra-articular structure was exposed. We subsequently acquired images (Samsung WB 100 26X Optical Zoom Wide, Beijing, China) of the intra-articular structures with the aid of a millimetric ruler. The images were digitized for morphometric analyses and analysed by using Netcad 5.1 Software (Ak Mühendislik, Ankara, Turkey). Results: The lateral and medial meniscal areas as well as the lateral and the medial articular surface areas of the tibia increased throughout gestation. We found that the medial articular surface areas were larger than the lateral articular surface areas, and the difference was statistically significant. The ratios of the mean lateral and medial meniscal areas to the lateral and medial articular surface areas, respectively, of the tibia decreased gradually from the first trimester to full term. The most common shape of the medial meniscus was crescentic (50%), and that of the lateral meniscus was C-shaped (61%). Conclusion: This study reveals the development of morphological changes and morphometric measurements of the menisci. PMID:28832324

Landscape influences on climate-related lake shrinkage at high latitudes

USGS Publications Warehouse

Roach, Jennifer K.; Griffith, Brad; Verbyla, David

2013-01-01

Climate-related declines in lake area have been identified across circumpolar regions and have been characterized by substantial spatial heterogeneity. An improved understanding of the mechanisms underlying lake area trends is necessary to predict where change is most likely to occur and to identify implications for high latitude reservoirs of carbon. Here, using a population of ca. 2300 lakes with statistically significant increasing and decreasing lake area trends spanning longitudinal and latitudinal gradients of ca. 1000 km in Alaska, we present evidence for a mechanism of lake area decline that involves the loss of surface water to groundwater systems. We show that lakes with significant declines in lake area were more likely to be located: (1) in burned areas; (2) on coarser, well-drained soils; and (3) farther from rivers compared to lakes that were increasing. These results indicate that postfire processes such as permafrost degradation, which also results from a warming climate, may promote lake drainage, particularly in coarse-textured soils and farther from rivers where overland flooding is less likely and downslope flow paths and negative hydraulic gradients between surface water and groundwater systems are more common. Movement of surface water to groundwater systems may lead to a deepening of subsurface flow paths and longer hydraulic residence time which has been linked to increased soil respiration and CO2 release to the atmosphere. By quantifying relationships between statewide coarse resolution maps of landscape characteristics and spatially heterogeneous responses of lakes to environmental change, we provide a means to identify at-risk lakes and landscapes and plan for a changing climate.

Is the planum temporale surface area a marker of hemispheric or regional language lateralization?

PubMed

Tzourio-Mazoyer, Nathalie; Crivello, Fabrice; Mazoyer, Bernard

2018-04-01

We investigated the association between the left planum temporale (PT) surface area or asymmetry and the hemispheric or regional functional asymmetries during language production and perception tasks in 287 healthy adults (BIL&GIN) who were matched for sex and handedness. The measurements of the PT surface area were performed after manually delineating the region using brain magnetic resonance images (MRI) and considering the Heschl's gyrus (HG) duplication pattern; the measurements either included (PT tot ) or did not include (PT post ) the second gyrus. A region encompassing both the PT and HG (HGPT) was also studied. Regardless of the ROI measured, 80% of the sample had a positive left minus right PT asymmetry. We first tested whether the PT tot , PT post and HGPT surface areas in the left or right hemispheres or PT asymmetries differed in groups of individuals varying in language lateralization by assessing their hemispheric index during a sentence production minus word list production task. We then investigated the association between these different measures of the PT anatomy and the regional asymmetries measured during the task. Regardless of the anatomical definition used, we observed no correlations between the left surface areas or asymmetries and the hemispheric or regional functional asymmetries during the language production task. We then performed a similar analysis using the same sample measuring language functional lateralization during speech listening tasks (i.e., listening to sentences and lists of words). Although the hemispheric lateralization during speech listening was not correlated with the left PT tot , PT post or HGPT surface areas or the PT asymmetries, significant positive correlations were observed between the asymmetries in these regions and the regional functional asymmetries measured in areas adjacent to the end of the Sylvian fissure while participants listened to the word lists or sentences. The PT asymmetry thus appears to be associated with the local functional asymmetries in auditory areas but is not a marker of inter-individual variability in language dominance.

Parameterizing atmosphere-land surface exchange for climate models with satellite data: A case study for the Southern Great Plains CART site

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

Gao, W.

High-resolution satellite data provide detailed, quantitative descriptions of land surface characteristics over large areas so that objective scale linkage becomes feasible. With the aid of satellite data, Sellers et al. and Wood and Lakshmi examined the linearity of processes scaled up from 30 m to 15 km. If the phenomenon is scale invariant, then the aggregated value of a function or flux is equivalent to the function computed from aggregated values of controlling variables. The linear relation may be realistic for limited land areas having no large surface contrasts to cause significant horizontal exchange. However, for areas with sharp surfacemore » contrasts, horizontal exchange and different dynamics in the atmospheric boundary may induce nonlinear interactions, such as at interfaces of land-water, forest-farm land, and irrigated crops-desert steppe. The linear approach, however, represents the simplest scenario, and is useful for developing an effective scheme for incorporating subgrid land surface processes into large-scale models. Our studies focus on coupling satellite data and ground measurements with a satellite-data-driven land surface model to parameterize surface fluxes for large-scale climate models. In this case study, we used surface spectral reflectance data from satellite remote sensing to characterize spatial and temporal changes in vegetation and associated surface parameters in an area of about 350 {times} 400 km covering the southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site of the US Department of Energy`s Atmospheric Radiation Measurement (ARM) Program.« less

Gradient Measurements of Nitrous Acid (hono)

NASA Astrophysics Data System (ADS)

Kleffmann, J.; Kurtenbach, R.; Lörzer, J.; Wiesen, P.; Kalthoff, N.; Vogel, B.; Vogel, H.

Nitrous acid (HONO) plays an important role in photochemical air pollution due to its photodissociation by solar UV radiation into hydroxyl radicals and thus significantly enhances photooxidation processes. Furthermore, HONO is an important indoor pol- lutant, which can react with amines leading to nitrosamines, which are known to be carcinogenic. Despite its importance in atmospheric chemistry the mechanisms lead- ing to HONO formation are still not completely understood at present. Although it is commonly proposed that HONO is formed by heterogeneous processes, i.e. by the conversion of NO2 on wet surfaces, it is still under discussion whether HONO produc- tion is dominated by the surface of particles or by the ground surface. Simultaneous vertical profile measurements of HONO, the precursor NO2 and the aerosol surface area, which could answer this question are not available at present. Accordingly, in the present study night-time HONO, NO2 and particle surface area gradients in the altitude range 10-190 m were measured on the meteorological tower at the Forschungszentrum Karlsruhe/Germany using a new, very sensitive HONO in- strument (LOPAP), a commercial NOx monitor and a SMPS system. For all gradient measurements during the campaign it was observed that the [HONO]/[NO2] ratio decreased with increasing altitude. In contrast, the particle sur- face area was found to be more or less constant. Accordingly, no correlation between the [HONO]/[NO2] ratio and the particle surface area was observed showing that HONO formation was dominated by processes on ground surfaces and that signifi- cant HONO formation on particle surfaces could be excluded for the measurement site.

Changes in root hydraulic conductivity facilitate the overall hydraulic response of rice (Oryza sativa L.) cultivars to salt and osmotic stress.

PubMed

Meng, Delong; Fricke, Wieland

2017-04-01

The aim of the present work was to assess the significance of changes in root AQP gene expression and hydraulic conductivity (Lp) in the regulation of water balance in two hydroponically-grown rice cultivars (Azucena, Bala) which differ in root morphology, stomatal regulation and aquaporin (AQP) isoform expression. Plants were exposed to NaCl (25 mM, 50 mM) and osmotic stress (5%, 10% PEG6000). Root Lp was determined for exuding root systems (osmotic forces driving water uptake; 'exudation Lp') and transpiring plants (hydrostatic forces dominating; 'transpiration-Lp'). Gene expression was analysed by qPCR. Stress treatments caused a consistent and significant decrease in plant growth, transpirational water loss, stomatal conductance, shoot-to-root surface area ratio and root Lp. Comparison of exudation-with transpiration-Lp supported a significant contribution of AQP-facilitated water flow to root water uptake. Changes in root Lp in response to treatments were correlated much stronger with root morphological characteristics, such as the number of main and lateral roots, surface area ratio of root to shoot and plant transpiration rate than with AQP gene expression. Changes in root Lp, involving AQP function, form an integral part of the plant hydraulic response to stress and facilitate changes in the root-to-shoot surface area ratio, transpiration and stomatal conductance. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Tyre char preparation from waste tyre rubber for dye removal from effluents.

PubMed

Mui, Edward L K; Cheung, W H; McKay, Gordon

2010-03-15

A number of chars from waste tyre rubber were prepared by carbonisation at 673-1173 K. The effects of holding time, heating rate and particle size on the textural characteristics and elemental composition of the resultant chars were investigated. It was demonstrated that temperatures over 773 K did not have a significant improvement on the total surface area but resulted in lower char yields following increased aromatisation. Modelling of dye adsorption isotherms showed that the Redlich-Peterson expression yields the best-fit between experimental and predicted data. Furthermore, for a larger sized dye like Acid Yellow 117 (MW=848 g/mol), the amount adsorbed by the tyre char is not directly proportional to the total surface area when compared with a commercial carbon, revealing that factors other than total surface area are involved in the adsorption potential of the tyre chars. (c) 2009 Elsevier B.V. All rights reserved.

Sea surface temperature of the coastal zones of France. Heat Capacity Mapping Mission (HCMM)

NASA Technical Reports Server (NTRS)

Deschamps, P. Y.; Frouin, R.; Cassanet, G.; Verger, F. (Principal Investigator)

1979-01-01

The author has identified the following significant results. HCMM data analysis shows some mesoscale features which were previously expected to occur: summer coastal upwellings in the Gulf of Lions, tidal fronts bordering the English Channel, and cooler surface waters at the continental shelf break. The analysis of the spectral variance density spectra show that the interpretation of the data usually is limited by the HCMM radiometric performance (noise levels) at wavenumbers below 5 km in the oceanic areas; from this analysis it may also be concluded that a decrease of the radiometric noise level down to 0.1 k against an increase of the ground resolution up to 2 km would give a better optimum of the radiometric performances in the oceanic areas. HCMM data appear to be useful for analysis of the sea surface temperature field, particularly in the very coastal area by profiting from the ground resolution of 500 m.

Spatial variability of specific surface area of arable soils in Poland

NASA Astrophysics Data System (ADS)

Sokolowski, S.; Sokolowska, Z.; Usowicz, B.

2012-04-01

Evaluation of soil spatial variability is an important issue in agrophysics and in environmental research. Knowledge of spatial variability of physico-chemical properties enables a better understanding of several processes that take place in soils. In particular, it is well known that mineralogical, organic, as well as particle-size compositions of soils vary in a wide range. Specific surface area of soils is one of the most significant characteristics of soils. It can be not only related to the type of soil, mainly to the content of clay, but also largely determines several physical and chemical properties of soils and is often used as a controlling factor in numerous biological processes. Knowledge of the specific surface area is necessary in calculating certain basic soil characteristics, such as the dielectric permeability of soil, water retention curve, water transport in the soil, cation exchange capacity and pesticide adsorption. The aim of the present study is two-fold. First, we carry out recognition of soil total specific surface area patterns in the territory of Poland and perform the investigation of features of its spatial variability. Next, semivariograms and fractal analysis are used to characterize and compare the spatial variability of soil specific surface area in two soil horizons (A and B). Specific surface area of about 1000 samples was determined by analyzing water vapor adsorption isotherms via the BET method. The collected data of the values of specific surface area of mineral soil representatives for the territory of Poland were then used to describe its spatial variability by employing geostatistical techniques and fractal theory. Using the data calculated for some selected points within the entire territory and along selected directions, the values of semivariance were determined. The slope of the regression line of the log-log plot of semi-variance versus the distance was used to estimate the fractal dimension, D. Specific surface area in A and B horizons was space-dependent, with the range of spatial dependence of about 2.5°. Variogram surfaces showed anisotropy of the specific surface area in both horizons with a trend toward the W to E directions. The smallest fractal dimensions were obtained for W to E directions and the highest values - for S to N directions. * The work was financially supported in part by the ESA Programme for European Cooperating States (PECS), No.98084 "SWEX-R, Soil Water and Energy Exchange/Research", AO3275.

Assessment of Surface Area Characteristics of Dental Implants with Gradual Bioactive Surface Treatment

NASA Astrophysics Data System (ADS)

Czan, Andrej; Babík, Ondrej; Miklos, Matej; Záušková, Lucia; Mezencevová, Viktória

2017-10-01

Since most of the implant surface is in direct contact with bone tissue, shape and integrity of said surface has great influence on successful osseointegration. Among other characteristics that predetermine titanium of different grades of pureness as ideal biomaterial, titanium shows high mechanical strength making precise miniature machining increasingly difficult. Current titanium-based implants are often anodized due to colour coding. This anodized layer has important functional properties for right usage and also bio-compatibility of dental implants. Physical method of anodizing and usage of anodizing mediums has a significant influence on the surface quality and itself functionality. However, basic requirement of the dental implant with satisfactory properties is quality of machined surface before anodizing. Roughness, for example, is factor affecting of time length of anodizing operation and so whole productivity. The paper is focused on monitoring of surface and area characteristics, such as roughness or surface integrity after different cutting conditions of miniature machining of dental implants and their impact on suitability for creation of satisfactory anodized layer with the correct biocompatible functional properties.

Finite element analysis on influence of implant surface treatments, connection and bone types.

PubMed

Santiago Junior, Joel Ferreira; Verri, Fellippo Ramos; Almeida, Daniel Augusto de Faria; de Souza Batista, Victor Eduardo; Lemos, Cleidiel Aparecido Araujo; Pellizzer, Eduardo Piza

2016-06-01

The aim of this study is to assess the effect of different dental implant designs, bone type, loading, and surface treatment on the stress distribution around the implant by using the 3D finite-element method. Twelve 3D models were developed with Invesalius 3.0, Rhinoceros 4.0, and Solidworks 2010 software. The analysis was processed using the FEMAP 10.2 and NeiNastran 10.0 software. The applied oblique forces were 200 N and 100 N. The results were analyzed using maps of maximum principal stress and bone microstrain. Statistical analysis was performed using ANOVA and Tukey's test. The results showed that the Morse taper design was most efficient in terms of its distribution of stresses (p<0.05); the external hexagon with platform switching did not show a significant difference from an external hexagon with a standard platform (p>0.05). The different bone types did not show a significant difference in the stress/strain distribution (p>0.05). The surface treatment increased areas of stress concentration under axial loading (p<0.05) and increased areas of microstrain under axial and oblique loading (p<0.05) on the cortical bone. The Morse taper design behaved better biomechanically in relation to the bone tissue. The treated surface increased areas of stress and strain on the cortical bone tissue. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of a pulsed CO2 laser operating at 9.4 μm on the surface morphology, reflectivity, and acid resistance of dental enamel below the threshold for melting

NASA Astrophysics Data System (ADS)

Kim, Jin Wan; Lee, Raymond; Chan, Kenneth H.; Jew, Jamison M.; Fried, Daniel

2017-02-01

Below the threshold for laser ablation, the mineral phase of enamel is converted into a purer phase hydroxyapatite with increased acid resistance. Studies suggest the possibility of achieving the conversion without visible surface alteration. In this study, changes in the surface morphology, reflectivity, and acid resistance were monitored with varying irradiation intensity. Bovine enamel specimens were irradiated using a CO2 laser operating at 9.4 μm with a Gaussian spatial beam profile-1.6 to 3.1 mm in diameter. After laser treatment, samples were subjected to demineralization to simulate the acidic intraoral conditions of dental decay. The resulting demineralization and erosion were assessed using polarization-sensitive optical coherence tomography, three-dimensional digital microscopy, and polarized light microscopy. Distinct changes in the surface morphology and the degree of inhibition were found within the laser-treated area in accordance with the laser intensity profile. Subtle visual changes were noted below the melting point for enamel that appear to correspond to thresholds for denaturation of the organic phase and thermal decomposition of the mineral phase. There was significant protection from laser irradiation in areas in which the reflectivity was not increased significantly, suggesting that aesthetically sensitive areas of the tooth can be treated for caries prevention.

Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

DTIC Science & Technology

2015-09-30

SST), sea surface height anomaly (SSH), chlorophyll a concentration (Chla), and primary productivity (PP). These data are available on similar...between the high and low area, and in areas with low abundance, chlorophyll a concentration was also a significant explanatory variable. For fin

Continuous measurement of soil evaporation in a drip-irrigated wine vineyard in a desert area

USDA-ARS?s Scientific Manuscript database

Evaporation from the soil surface (E) can be a significant source of water loss in arid areas. In sparsely vegetated systems, E is expected to be a function of soil, climate, irrigation regime, precipitation patterns, and plant canopy development, and will therefore change dynamically at both daily ...

Vapor-Phase Nanopatterning of Aminosilanes with Electron Beam Lithography: Understanding and Minimizing Background Functionalization.

PubMed

Fetterly, Christopher R; Olsen, Brian C; Luber, Erik J; Buriak, Jillian M

2018-04-24

Electron beam lithography (EBL) is a highly precise, serial method for patterning surfaces. Positive tone EBL resists enable patterned exposure of the underlying surface, which can be subsequently functionalized for the application of interest. In the case of widely used native oxide-capped silicon surfaces, coupling an activated silane with electron beam lithography would enable nanoscale chemical patterning of the exposed regions. Aminoalkoxysilanes are extremely useful due to their reactive amino functionality but have seen little attention for nanopatterning silicon surfaces with an EBL resist due to background contamination. In this work, we investigated three commercial positive tone EBL resists, PMMA (950k and 495k) and ZEP520A (57k), as templates for vapor-phase patterning of two commonly used aminoalkoxysilanes, 3-aminopropyltrimethoxysilane (APTMS) and 3-aminopropyldiisopropylethoxysilane (APDIPES). The PMMA resists were susceptible to significant background reaction within unpatterned areas, a problem that was particularly acute with APTMS. On the other hand, with both APTMS and APDIPES exposure, unpatterned regions of silicon covered by the ZEP520A resist emerged pristine, as shown both with SEM images of the surfaces of the underlying silicon and through the lack of electrostatically driven binding of negatively charged gold nanoparticles. The ZEP520A resist allowed for the highly selective deposition of these alkoxyaminosilanes in the exposed areas, leaving the unpatterned areas clean, a claim also supported by contact angle measurements with four probe liquids and X-ray photoelectron spectroscopy (XPS). We investigated the mechanistic reasons for the stark contrast between the PMMA resists and ZEP520A, and it was found that the efficacy of resist removal appeared to be the critical factor in reducing the background functionalization. Differences in the molecular weight of the PMMA resists and the resulting influence on APTMS diffusion through the resist films are unlikely to have a significant impact. Area-selective nanopatterning of 15 nm gold nanoparticles using the ZEP520A resist was demonstrated, with no observable background conjugation noted in the unexposed areas on the silicon surface by SEM.

Infrared broadband metasurface absorber for reducing the thermal mass of a microbolometer.

PubMed

Jung, Joo-Yun; Song, Kyungjun; Choi, Jun-Hyuk; Lee, Jihye; Choi, Dae-Geun; Jeong, Jun-Ho; Neikirk, Dean P

2017-03-27

We demonstrate an infrared broadband metasurface absorber that is suitable for increasing the response speed of a microbolometer by reducing its thermal mass. A large fraction of holes are made in a periodic pattern on a thin lossy metal layer characterised with a non-dispersive effective surface impedance. This can be used as a non-resonant metasurface that can be integrated with a Salisbury screen absorber to construct an absorbing membrane for a microbolometer that can significantly reduce the thermal mass while maintaining high infrared broadband absorption in the long wavelength infrared (LWIR) band. The non-dispersive effective surface impedance can be matched to the free space by optimising the surface resistance of the thin lossy metal layer depending on the size of the patterned holes by using a dc approximation method. In experiments a high broadband absorption was maintained even when the fill factor of the absorbing area was reduced to 28% (hole area: 72%), and it was theoretically maintained even when the fill factor of the absorbing area was reduced to 19% (hole area: 81%). Therefore, a metasurface with a non-dispersive effective surface impedance is a promising solution for reducing the thermal mass of infrared microbolometer pixels.

Significant enhancement of power conversion efficiency for dye sensitized solar cell using 1D/3D network nanostructures as photoanodes

PubMed Central

Wang, Hao; Wang, Baoyuan; Yu, Jichao; Hu, Yunxia; Xia, Chen; Zhang, Jun; Liu, Rong

2015-01-01

The single–crystalline TiO2 nanorod arrays with rutile phase have attracted much attention in the dye sensitized solar cells (DSSCs) applications because of their superior chemical stability, better electron transport properties, higher refractive index and low production cost. However, it suffers from a low surface area as compared with TiO2 nanoparticle films. In order to enlarge the surface area of TiO2 nanorod arrays, the 1D nanorods/3D nanotubes sample was synthesized using a facile two-step hydrothermal process involving hydrothermal growth 1D/3D nanorods and followed by post-etching treatment. In such bi-layer structure, the oriented TiO2 nanorods layer could provide direct pathway for fast electron transportation, and the 3D nanotubes layer offers a higher surface area for dye loading, therefore, the 1D nanorods/3D nanotubes photoanode exhibited faster electron transport and higher surface area than either 1D or 3D nanostructures alone, and an highest efficiency of 7.68% was achieved for the DSSCs based on 1D nanorods/3D nanotubes photoanode with further TiCl4 treatment. PMID:25800933

Modified Ni-Cu catalysts for ethanol steam reforming

NASA Astrophysics Data System (ADS)

Dan, M.; Mihet, M.; Almasan, V.; Borodi, G.; Katona, G.; Muresan, L.; Lazar, M. D.

2013-11-01

Three Ni-Cu catalysts, having different Cu content, supported on γ-alumina were synthesized by wet co-impregnation method, characterized and tested in the ethanol steam reforming (ESR) reaction. The catalysts were characterized for determination of: total surface area and porosity (N2 adsorption - desorption using BET and Dollimer Heal methods), Ni surface area (hydrogen chemisorption), crystallinity and Ni crystallites size (X-Ray Diffraction), type of catalytic active centers (Hydrogen Temperature Programmed Reduction). Total surface area and Ni crystallites size are not significantly influenced by the addition of Cu, while Ni surface area is drastically diminished by increasing of Cu concentration. Steam reforming experiments were performed at atmospheric pressure, temperature range 150-350°C, and ethanol - water molar ration of 1 at 30, using Ar as carrier gas. Ethanol conversion and hydrogen production increase by the addition of Cu. At 350°C there is a direct connection between hydrogen production and Cu concentration. Catalysts deactivation in 24h time on stream was studied by Transmission Electron Microscopy (TEM) and temperature-programmed reduction (TPR) on used catalysts. Coke deposition was observed at all studied temperatures; at 150°C amorphous carbon was evidenced, while at 350°C crystalline, filamentous carbon is formed.

Water-quality characteristics in runoff for three discovery farms in North Dakota, 2008-12

USGS Publications Warehouse

Nustad, Rochelle A.; Rowland, Kathleen M.; Wiederholt, Ronald

2015-01-01

Consistent patterns in water quality emerged at each individual farm, but similarities among farms also were observed. Suspended sediment, total phosphorus, and ammonia concentrations generally decreased downstream from feeding areas, and were primarily affected by surface runoff processes such as dilution, settling out of sediment, or vegetative uptake. Because surface runoff affects these constituents, increased annual surface runoff volume tended to result in increased loads and yields. No significant change in nitrate plus nitrite concentration were observed downstream from feeding areas because additional processes such as high solubility, nitrification, denitrification, and surface-groundwater interaction affect nitrate plus nitrite. For nitrate plus nitrite, increases in annual runoff volume did not consistently relate to increases in annual loads and yields. It seems that temporal distribution of precipitation and surface-groundwater interaction affected nitrate plus nitrite loads and yields. For surface drainage sites, the primary form of nitrogen was organic nitrogen whereas for subsurface drainage sites, the primary form of nitrogen was nitrate plus nitrite nitrogen.

Surface rearrangement of water-immersed hydrophobic solids by gaseous nanobubbles.

PubMed

Tarábková, Hana; Bastl, Zdeněk; Janda, Pavel

2014-12-09

Interactions of gaseous (ambient) nanobubbles (10-100 nm diameter) with different hydrophobic materials-Teflon, polystyrene, paraffin, and basal plane highly ordered pyrolytic graphite (HOPG)-are studied by AFM in situ and ex situ. Exactly identical surface locations are examined before and after exposure to ambient gas nanobubbles in deionized water and compared for nanomorphological changes. While freely flooded/immersed surfaces, regularly occupied by nanobubbles, do not exhibit resolvable alterations, significant surface rearrangement is found on whole flooded area after mild pressure drop (10 kPa) applied on the solid-liquid interface. Nanopattern and its characteristic dimension appear to be material specific and solely reflect surface-nanobubble interaction. Mild, nonswelling, noncorrosive conditions (20 °C, deionized water) prevent intervention of chemical reaction and high-energy-demanding processes. Experimental results, in accordance with the presented model, indicate that the mild pressure drop triggers expansion of pinned nanobubbles, imposing local tensile stress on the solid surface. Consequently, nanobubbles should be considered as large-area nanoscale patterning elements.

Pulmonary function test in healthy school children of 8 to 14 years age in south Gujarat region, India

PubMed Central

Doctor, Tahera H.; Trivedi, Sangeeta S.; Chudasama, Rajesh K.

2010-01-01

Objective: To obtain reference values for FEV1, FVC, FEV1% and PEFR among children aged 8-14 years in south Gujarat region of India. Materials and Methods: This cross-sectional study was conducted among 655 normal healthy school children (408 boys and 247 girls) of Surat city aged 8 to 14 years studying in V to VII standard during November 2007 to April 2008. Height, weight, body surface area were measured. All included children were tested in a sitting position with the head straight after taking written consent from parents. Spirometry was done using the spirometer “Spirolab II” MIR 010. Spirometer used in the study facilitates the total valuation of lung function including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory volume ratio in one second (FEV1%) and peak expiratory flow rate (PEFR). Results: FVC, FEV1 and PEFR were found to be statistically significant in the study groups. For FVC and FEV1, highest correlation was found with age in girls and height in boys. For FEV1%, significant negative correlation was found with age and height in both sexes, but positive correlation was found with surface area. Similarly, PEFR showed highest correlation with surface area in boys and girls. Conclusion: Variables such as FVC, FEV1 and PEFR show good positive correlation with height, age and body surface area in both sexes. There is a need to have regional values for the prediction of normal spirometric parameters in a country like India with considerable diversity. PMID:20931033

Sunglasses with thick temples and frame constrict temporal visual field.

PubMed

Denion, Eric; Dugué, Audrey Emmanuelle; Augy, Sylvain; Coffin-Pichonnet, Sophie; Mouriaux, Frédéric

2013-12-01

Our aim was to compare the impact of two types of sunglasses on visual field and glare: one ("thick sunglasses") with a thick plastic frame and wide temples and one ("thin sunglasses") with a thin metal frame and thin temples. Using the Goldmann perimeter, visual field surface areas (cm²) were calculated as projections on a 30-cm virtual cupola. A V4 test object was used, from seen to unseen, in 15 healthy volunteers in the primary position of gaze ("base visual field"), then allowing eye motion ("eye motion visual field") without glasses, then with "thin sunglasses," followed by "thick sunglasses." Visual field surface area differences greater than the 14% reproducibility error of the method and having a p < 0.05 were considered significant. A glare test was done using a surgical lighting system pointed at the eye(s) at different incidence angles. No significant "base visual field" or "eye motion visual field" surface area variations were noted when comparing tests done without glasses and with the "thin sunglasses." In contrast, a 22% "eye motion visual field" surface area decrease (p < 0.001) was noted when comparing tests done without glasses and with "thick sunglasses." This decrease was most severe in the temporal quadrant (-33%; p < 0.001). All subjects reported less lateral glare with the "thick sunglasses" than with the "thin sunglasses" (p < 0.001). The better protection from lateral glare offered by "thick sunglasses" is offset by the much poorer ability to use lateral space exploration; this results in a loss of most, if not all, of the additional visual field gained through eye motion.

Regional climate model assessment of the urban land-surface forcing over central Europe

NASA Astrophysics Data System (ADS)

Huszar, P.; Halenka, T.; Belda, M.; Zak, M.; Sindelarova, K.; Miksovsky, J.

2014-07-01

For the purpose of qualifying and quantifying the climate impact of cities and urban surfaces in general on climate of central Europe, the surface parameterization in regional climate model RegCM4 has been extended with the Single Layer Urban Canopy Model (SLUCM). A set of experiments was performed over the period of 2005-2009 for central Europe, either without considering urban surfaces or with the SLUCM treatment. Results show a statistically significant impact of urbanized surfaces on temperature (up to 1.5 K increase in summer) as well as on the boundary layer height (increases up to 50 m). Urbanization further influences surface wind with a winter decrease up to -0.6 m s-1, though both increases and decreases were detected in summer depending on the location relative to the cities and daytime (changes up to 0.3 m s-1). Urban surfaces significantly reduce evaporation and thus the humidity over the surface. This impacts the simulated summer precipitation rate, showing decrease over cities up to -2 mm day-1. Significant temperature increases are simulated over higher elevations as well, not only within the urban canopy layer. With the urban parameterization, the climate model better describes the diurnal temperature variation, reducing the cold afternoon and evening bias of RegCM4. Sensitivity experiments were carried out to quantify the response of the meteorological conditions to changes in the parameters specific to the urban environment such as street width, building height, albedo of the roofs and anthropogenic heat release. The results proved to be rather robust and the choice of the key SLUCM parameters impacts them only slightly (mainly temperature, boundary layer height and wind velocity). Statistically significant impacts are modeled not only over large urbanized areas, but the influence of the cities is also evident over rural areas without major urban surfaces. It is shown that this is the result of the combined effect of the distant influence of the cities and the influence of the minor local urban surface coverage.

Regional climate model assessment of the urban land-surface forcing over central Europe

NASA Astrophysics Data System (ADS)

Huszar, P.; Halenka, T.; Belda, M.; Zak, M.; Sindelarova, K.; Miksovsky, J.

2014-11-01

For the purpose of qualifying and quantifying the climate impact of cities and urban surfaces in general on climate of central Europe, the surface parameterization in regional climate model RegCM4 has been extended with the Single-layer Urban Canopy Model (SLUCM). A set of experiments was performed over the period of 2005-2009 for central Europe, either without considering urban surfaces or with the SLUCM treatment. Results show a statistically significant impact of urbanized surfaces on temperature (up to 1.5 K increase in summer) as well as on the boundary layer height (increases up to 50 m). Urbanization further influences surface wind with a winter decrease up to -0.6 m s-1, though both increases and decreases were detected in summer depending on the location relative to the cities and daytime (changes up to 0.3 m s-1). Urban surfaces significantly reduce the humidity over the surface. This impacts the simulated summer precipitation rate, showing a decrease over cities of up to -2 mm day-1. Significant temperature increases are simulated over higher altitudes as well, not only within the urban canopy layer. With the urban parameterization, the climate model better describes the diurnal temperature variation, reducing the cold afternoon and evening bias of RegCM4. Sensitivity experiments were carried out to quantify the response of the meteorological conditions to changes in the parameters specific to the urban environment, such as street width, building height, albedo of the roofs and anthropogenic heat release. The results proved to be rather robust and the choice of the key SLUCM parameters impacts them only slightly (mainly temperature, boundary layer height and wind velocity). Statistically significant impacts are modelled not only over large urbanized areas, but the influence of the cities is also evident over rural areas without major urban surfaces. It is shown that this is the result of the combined effect of the distant influence of the cities and the influence of the minor local urban surface coverage.

Exploring Ag(111) Substrate for Epitaxially Growing Monolayer Stanene: A First-Principles Study

PubMed Central

Gao, Junfeng; Zhang, Gang; Zhang, Yong-Wei

2016-01-01

Stanene, a two-dimensional topological insulator composed of Sn atoms in a hexagonal lattice, is a promising contender to Si in nanoelectronics. Currently it is still a significant challenge to achieve large-area, high-quality monolayer stanene. We explore the potential of Ag(111) surface as an ideal substrate for the epitaxial growth of monolayer stanene. Using first-principles calculations, we study the stability of the structure of stanene in different epitaxial relations with respect to Ag(111) surface, and also the diffusion behavior of Sn adatom on Ag(111) surface. Our study reveals that: (1) the hexagonal structure of stanene monolayer is well reserved on Ag(111) surface; (2) the height of epitaxial stanene monolayer is comparable to the step height of the substrate, enabling the growth to cross the surface step and achieve a large-area stanene; (3) the perfect lattice structure of free-standing stanene can be achieved once the epitaxial stanene monolayer is detached from Ag(111) surface; and finally (4) the diffusion barrier of Sn adatom on Ag(111) surface is found to be only 0.041 eV, allowing the epitaxial growth of stanene monolayer even at low temperatures. Our above revelations strongly suggest that Ag(111) surface is an ideal candidate for growing large-area, high-quality monolayer stanene. PMID:27373464

Microscopic asperity contact and deformation of ultrahigh molecular weight polyethylene bearing surfaces.

PubMed

Wang, F C; Jin, Z M; McEwen, H M J; Fisher, J

2003-01-01

The effect of the roughness and topography of ultrahigh molecular weight polyethylene (UHMWPE) bearing surfaces on the microscopic contact mechanics with a metallic counterface was investigated in the present study. Both simple sinusoidal roughness forms, with a wide range of amplitudes and wavelengths, and real surface topographies, measured before and after wear testing in a simple pin-on-plate machine, were considered in the theoretical analysis. The finite difference method was used to solve the microscopic contact between the rough UHMWPE bearing surface and a smooth hard counterface. The fast Fourier transform (FFT) was used to cope with the large number of mesh points required to represent the surface topography of the UHMWPE bearing surface. It was found that only isolated asperity contacts occurred under physiological loading, and the real contact area was only a small fraction of the nominal contact area. Consequently, the average contact pressure experienced at the articulating surfaces was significantly higher than the nominal contact pressure. Furthermore, it was shown that the majority of asperities on the worn UHMWPE pin were deformed in the elastic region, and consideration of the plastic deformation only resulted in a negligible increase in the predicted asperity contact area. Microscopic asperity contact and deformation mechanisms may play an important role in the understanding of the wear mechanisms of UHMWPE bearing surfaces.

Drug release through liposome pores.

PubMed

Dan, Nily

2015-02-01

Electrical, ultrasound and other types of external fields are known to induce the formation of pores in cellular and model membranes. This paper examines drug release through field induced liposome pores using Monte Carlo simulations. We find that drug release rates vary as a function of pore size and spacing, as well as the overall fraction of surface area covered by pores: The rate of release from liposomes is found to increase rapidly with pore surface coverage, approaching that of the fully ruptured liposome at fractional pore areas. For a given pore surface coverage, the pore size affects the release rate in the limit of low coverage, but not when the pores cover a relatively high fraction of the liposome surface area. On the other hand, for a given pore size and surface coverage, the distribution of pores significantly affects the release in the limit of high surface coverage: The rate of release from a liposome covered with a regularly spaced array of pores is, in this limit, higher than the release rate from (most) systems where the pores are distributed randomly on the liposome surface. In contrast, there is little effect of the pore distribution on release when the pore surface coverage is low. The simulation results are in good agreement with the predictions of detailed diffusion models. Copyright © 2014 Elsevier B.V. All rights reserved.

Integration of Heterogenous Digital Surface Models

NASA Astrophysics Data System (ADS)

Boesch, R.; Ginzler, C.

2011-08-01

The application of extended digital surface models often reveals, that despite an acceptable global accuracy for a given dataset, the local accuracy of the model can vary in a wide range. For high resolution applications which cover the spatial extent of a whole country, this can be a major drawback. Within the Swiss National Forest Inventory (NFI), two digital surface models are available, one derived from LiDAR point data and the other from aerial images. Automatic photogrammetric image matching with ADS80 aerial infrared images with 25cm and 50cm resolution is used to generate a surface model (ADS-DSM) with 1m resolution covering whole switzerland (approx. 41000 km2). The spatially corresponding LiDAR dataset has a global point density of 0.5 points per m2 and is mainly used in applications as interpolated grid with 2m resolution (LiDAR-DSM). Although both surface models seem to offer a comparable accuracy from a global view, local analysis shows significant differences. Both datasets have been acquired over several years. Concerning LiDAR-DSM, different flight patterns and inconsistent quality control result in a significantly varying point density. The image acquisition of the ADS-DSM is also stretched over several years and the model generation is hampered by clouds, varying illumination and shadow effects. Nevertheless many classification and feature extraction applications requiring high resolution data depend on the local accuracy of the used surface model, therefore precise knowledge of the local data quality is essential. The commercial photogrammetric software NGATE (part of SOCET SET) generates the image based surface model (ADS-DSM) and delivers also a map with figures of merit (FOM) of the matching process for each calculated height pixel. The FOM-map contains matching codes like high slope, excessive shift or low correlation. For the generation of the LiDAR-DSM only first- and last-pulse data was available. Therefore only the point distribution can be used to derive a local accuracy measure. For the calculation of a robust point distribution measure, a constrained triangulation of local points (within an area of 100m2) has been implemented using the Open Source project CGAL. The area of each triangle is a measure for the spatial distribution of raw points in this local area. Combining the FOM-map with the local evaluation of LiDAR points allows an appropriate local accuracy evaluation of both surface models. The currently implemented strategy ("partial replacement") uses the hypothesis, that the ADS-DSM is superior due to its better global accuracy of 1m. If the local analysis of the FOM-map within the 100m2 area shows significant matching errors, the corresponding area of the triangulated LiDAR points is analyzed. If the point density and distribution is sufficient, the LiDAR-DSM will be used in favor of the ADS-DSM at this location. If the local triangulation reflects low point density or the variance of triangle areas exceeds a threshold, the investigated location will be marked as NODATA area. In a future implementation ("anisotropic fusion") an anisotropic inverse distance weighting (IDW) will be used, which merges both surface models in the point data space by using FOM-map and local triangulation to derive a quality weight for each of the interpolation points. The "partial replacement" implementation and the "fusion" prototype for the anisotropic IDW make use of the Open Source projects CGAL (Computational Geometry Algorithms Library), GDAL (Geospatial Data Abstraction Library) and OpenCV (Open Source Computer Vision).

The Enhancement of Water Ice Content in the Local Area Northeast of Arcadia Planitia: Evidence from Neutron Data from HEND (Mars Odyssey) and Elevation from MOLA (MGS)

NASA Technical Reports Server (NTRS)

Sanin, A. B.; Mitrofanov, I. G.; Kozyrev, A. S.; Litvak, M. L.; Tretyakov, V.; Smith, D. E.; Zuber, M. T.; Boynton, W.; Saunders, R. S.

2003-01-01

The first year of neutron mapping measurements from the Mars Odyssey spacecraft revealed enormous hydrogen-rich regions in the southern and northern hemispheres of the Martian crust that imply significant amounts of near surface water ice. The hydrogen-rich areas of the southern and northern regions appear generally comparable in spatial extent and water ice content. This observation is interesting in light of topography measured by the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor (MGS) spacecraft, which shows a significant difference in elevation between northern lowlands and southern highlands that could imply a difference in seasonal CO2 condensation. In this study we correlate the high energy neutron flux observed by HEND (Mars Odyssey) and surface elevation measured by MOLA in order to interpret the seasonal change in epithermal neutron flux in terms near-surface water ice content.

Evaluation of Adaptive Subdivision Method on Mobile Device

NASA Astrophysics Data System (ADS)

Rahim, Mohd Shafry Mohd; Isa, Siti Aida Mohd; Rehman, Amjad; Saba, Tanzila

2013-06-01

Recently, there are significant improvements in the capabilities of mobile devices; but rendering large 3D object is still tedious because of the constraint in resources of mobile devices. To reduce storage requirement, 3D object is simplified but certain area of curvature is compromised and the surface will not be smooth. Therefore a method to smoother selected area of a curvature is implemented. One of the popular methods is adaptive subdivision method. Experiments are performed using two data with results based on processing time, rendering speed and the appearance of the object on the devices. The result shows a downfall in frame rate performance due to the increase in the number of triangles with each level of iteration while the processing time of generating the new mesh also significantly increase. Since there is a difference in screen size between the devices the surface on the iPhone appears to have more triangles and more compact than the surface displayed on the iPad. [Figure not available: see fulltext.

Changes in surface area of the Böön Tsagaan and Orog lakes (Mongolia, Valley of the Lakes, 1974-2013) compared to climate and permafrost changes

NASA Astrophysics Data System (ADS)

Szumińska, Danuta

2016-07-01

The main aim of the study is the analysis of changes in surface area of lake Böön Tsagaan (45°35‧N, 99°8‧E) and lake Orog (45°3‧N, 100°44‧E) taking place in the last 40 years in the context of climate conditions and permafrost degradation. The lakes, located in Central Mongolia, at the borderline of permafrost range are fed predominantly by river waters and groundwater from the surrounding mountain areas, characterized by continuous and discontinuous permafrost occurrence - mostly the Khangai. The analysis of the Böön Tsagaan and Orog lake surface area in 1974-2013 was conducted based on satellite images, whereas climate conditions were analysed using the NOAA climate data and CRU dataset. Principal Component Analysis (PCA) was used to study the relationship patterns between the climatic factors and changes in the surface area of the lakes. A tendency for a decrease in surface area, intermittent with short episodes of resupply, was observed in both studied lakes. Climate changes recorded in the analysed period had both direct and indirect impacts on water supply to lakes. Taking into account the results of PCA analysis, the most significant factors include: fluctuation of annual precipitation, increase in air temperature and thickness of snow cover. The extended duration of snow cover in the last decades of the 20th century may constitute a key factor in relation to permafrost degradation.

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

Boxley, Chett J.; Kadota, Rod

This research program performed by Ceramatec may significantly increase the beneficial utilization of fly ash, and improve the overall performance of high quality animal litter products. Ceramatec has developed a novel high surface area material, which is capable of ammonia adsorption. High surface area zeolites when combined with agglomerated fly ash can significantly reduce the use of naturally mined materials (i.e. clay bentonite) for animal litter manufacture. This not only preserves natural resources and the natural environment, but it also will reduce CO 2 emissions, via the reduced need for heavy mining equipment. This novel animal litter is made withmore » over 85% of recycled materials, thus preventing their disposition to landfills. The novel litter material is similar to traditional clay-like litters, and it is clumpable and has superior odor control properties.« less

Preliminary results of fisheries investigation associated with Skylab-3

NASA Technical Reports Server (NTRS)

Savastano, K.; Pastula, E., Jr.; Woods, G.; Faller, K.

1974-01-01

The purpose of the 15-month investigation now in the analysis phase is to establish the feasibility of utilizing remotely sensed data acquired from aircraft and satellite platforms to provide information concerning the distribution and abundance of oceanic gamefish. Data from the test area, jointly acquired by private and professional fishermen and NASA and NOAA/NMFS elements, in the northeastern Gulf of Mexico has made possible the identification of significant environmental parameters for white marlin. Predictive models based on catch data and surface truth information have been developed and have demonstrated potential for reducing search significantly by identifying areas which have a high probability of being productive. Three of the parameters utilized by the model, chlorophyll-a, sea surface temperature and turbidity have been inferred from aircraft sensor data.

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.

A DNS study of the physical mechanisms associated with density ratio influence on turbulent burning velocity in premixed flames

NASA Astrophysics Data System (ADS)

Lipatnikov, Andrei N.; Chomiak, Jerzy; Sabelnikov, Vladimir A.; Nishiki, Shinnosuke; Hasegawa, Tatsuya

2018-01-01

Data obtained in 3D direct numerical simulations of statistically planar, 1D weakly turbulent flames characterised by different density ratios σ are analysed to study the influence of thermal expansion on flame surface area and burning rate. Results show that, on the one hand, the pressure gradient induced within a flame brush owing to heat release in flamelets significantly accelerates the unburned gas that deeply intrudes into the combustion products in the form of an unburned mixture finger, thus causing large-scale oscillations of the burning rate and flame brush thickness. Under the conditions of the present simulations, the contribution of this mechanism to the creation of the flame surface area is substantial and is increased by σ, thus implying an increase in the burning rate by σ. On the other hand, the total flame surface areas simulated at σ = 7.53 and 2.5 are approximately equal. The apparent inconsistency between these results implies the existence of another thermal expansion effect that reduces the influence of σ on the flame surface area and burning rate. Investigation of the issue shows that the flow acceleration by the combustion-induced pressure gradient not only creates the flame surface area by pushing the finger tip into the products, but also mitigates wrinkling of the flame surface (the side surface of the finger) by turbulent eddies. The latter effect is attributed to the high-speed (at σ = 7.53) axial flow of the unburned gas, which is induced by the axial pressure gradient within the flame brush (and the finger). This axial flow acceleration reduces the residence time of a turbulent eddy in an unburned zone of the flame brush (e.g. within the finger). Therefore, the capability of the eddy for wrinkling the flamelet surface (e.g. the side finger surface) is weakened owing to a shorter residence time.

Urban Surface Radiative Energy Budgets Determined Using Aircraft Scanner Data

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Quattrochi, Dale A.; Rickman, Doug L.; Estes, Maury G.; Arnold, James E. (Technical Monitor)

2002-01-01

It is estimated that by the year 2025, 80% of the world's population will live in cities. The extent of these urban areas across the world can be seen in an image of city lights from the Defense Meteorological Satellite Program. In many areas of North America and Europe, it is difficult to separate individual cities because of the dramatic growth and sprawl of urbanized areas. This conversion of the natural landscape vegetation into man-made urban structures such as roads and buildings drastically alter the regional surface energy budgets, hydrology, precipitation patterns, and meteorology. One of the earliest recognized and measured phenomena of urbanization is the urban heat island (UHI) which was reported as early as 1833 for London and 1862 for Paris. The urban heat island results from the energy that is absorbed by man-made materials during the day and is released at night resulting in the heating of the air within the urban area. The magnitude of the air temperature difference between the urban and surrounding countryside is highly dependent on the structure of the urban area, amount of solar immolation received during the day, and atmospheric conditions during the night. These night time air temperature differences can be in the range of 2 to 5 C. or greater. Although day time air temperature differences between urban areas and the countryside exists during the day, atmospheric mixing and stability reduce the magnitude. This phenomena is not limited to large urban areas, but also occurs in smaller metropolitan areas. The UHI has significant impacts on the urban air quality, meteorology, energy use, and human health. The UPI can be mitigated through increasing the amount of vegetation and modification of urban surfaces using high albedo materials for roofs and paved surfaces. To understand why the urban heat island phenomenon exists it is useful to define the surface in terms of the surface energy budget. Surface temperature and albedo is a major component of the surface energy budget. Knowledge of it is important in any attempt to describe the radiative and mass fluxes which occur at the surface. Use of energy terms in modeling surface energy budgets allows the direct comparison of various land surfaces encountered in a urban landscape, from vegetated (forest and herbaceous) to non-vegetated (bare soil, roads, and buildings). These terms are also easily measured using remote sensing from aircraft or satellite platforms allowing one to examine the spacial variability. The partitioning of energy budget terms depends on the surface type. In natural landscapes, the partitioning is dependent on canopy biomass, leaf area index, aerodynamic roughness, and moisture status, all of which are influenced by the development stage of the ecosystem. In urban landscapes, coverage by man-made materials substantially alters the surface face energy budget. The remotely sensed data obtained from aircraft and satellites, when properly calibrated allows the measurement of important terms in the radiative surface energy budget a urban landscape scale.

Use of aerial photos and field reconnaissance to predict groundwater flow of a karst area in the Inner Bluegrass Region of Kentucky

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

Gremos, K.; Sendlein, L.V.A.

1993-03-01

Significant areas of the continental US (Kentucky included) are underlain by karstified limestone. In many of these areas agriculture is a leading business and a potential non-point source of pollution to the groundwater. A study is underway to assess the Best Management Practices (BMP) on a farm in north-central Woodford County in Kentucky. As part of the study, various computer-based decision models for integrated farm operation will be assessed. Because surface area and run off are integral parts of all of these models, diversion of surface run off through karst features such as sinkholes will modify predictions from these models.more » This study utilizes areal photographs to identify all sinkholes on the property and characterize their morphometric parameters such as length, width, depth, and area and distribution. Sink hole areas represent approximately 10 percent of the area and all but a few discharge within the basin monitored as part of the model. The bedrock geology and fractures of the area have been defined using fracture trace analysis and a rectified drainage linear analysis. Surface drainage patterns, spring distribution, and stream and spring discharge data have been collected. Dye tracing has identified groundwater basins whose catchment area is outside the boundaries of the study site.« less

Assessment of sea water inundation along Daboo creek area in Indus Delta Region, Pakistan

NASA Astrophysics Data System (ADS)

Zia, Ibrahim; Zafar, Hina; Shahzad, Muhammad I.; Meraj, Mohsin; Kazmi, Jamil H.

2017-12-01

Indus Deltaic Region (IDR) in Pakistan is an erosion vulnerable coast due to the high deep water wave energy. Livelihood of millions of people depends on the fisheries and mangrove forests in IDR. IDR consists of many creeks where Daboo is a major creek located at southeast of the largest city of Pakistan, Karachi. Unfortunately, there has been no detailed study to analyze the damages of sea water intrusion at a large temporal and spatial scale. Therefore, this study is designed to estimate the effects of sea water inundation based on changing sea water surface salinity and sea surface temperature (SST). Sea surface salinity and SST data from two different surveys in Daboo creek during 1986 and 2010 are analyzed to estimate the damages and extent of sea water intrusion. Mean salinity has increased 33.33% whereas mean SST decreased 13.79% from 1987 to 2010. Spatio-temporal analysis of creek area using LANDSAT 5 Thematic mapper (TM) data for the years 1987 and 2010 shows significant amount of erosion at macro scale. Creek area has increased approximately 9.93% (260.86 m2 per year) which is roughly equal to 60 extensive sized shrimp farms. Further Land Use Land Cover (LULC) analyses for years 2001 and 2014 using LANDSAT 7 Enhanced Thematic Mapper Plus (ETM+) has indicated 42.3% decrease in cultivated land. Wet mud flats have spread out at the inner mouth of creek with enormous increase of 123.3%. Significant sea water intrusion has increased the area of barren land by 37.9%. This also resulted in overall decrease of 6.7% in area covered by mangroves. Therefore, this study recorded a significant evidence of sea water intrusion in IDR that has caused serious damages to community living in the area, economical losses. Additionally, it has also changed the environment by reducing creek biological productivity as reported by earlier studies over other regions of the world.

Spectral analysis of 87-lead body surface signal-averaged ECGs in patients with previous anterior myocardial infarction as a marker of ventricular tachycardia.

PubMed

Hosoya, Y; Kubota, I; Shibata, T; Yamaki, M; Ikeda, K; Tomoike, H

1992-06-01

There were few studies on the relation between the body surface distribution of high- and low-frequency components within the QRS complex and ventricular tachycardia (VT). Eighty-seven signal-averaged ECGs were obtained from 30 normal subjects (N group) and 30 patients with previous anterior myocardial infarction (MI) with VT (MI-VT[+] group, n = 10) or without VT (MI-VT[-] group, n = 20). The onset and offset of the QRS complex were determined from 87-lead root mean square values computed from the averaged (but not filtered) ECG waveforms. Fast Fourier transform analysis was performed on signal-averaged ECG. The resulting Fourier coefficients were attenuated by use of the transfer function, and then inverse transform was done with five frequency ranges (0-25, 25-40, 40-80, 80-150, and 150-250 Hz). From the QRS onset to the QRS offset, the time integration of the absolute value of reconstructed waveforms was calculated for each of the five frequency ranges. The body surface distributions of these areas were expressed as QRS area maps. The maximal values of QRS area maps were compared among the three groups. In the frequency ranges of 0-25 and 150-250 Hz, there were no significant differences in the maximal values among these three groups. Both MI groups had significantly smaller maximal values of QRS area maps in the frequency ranges of 25-40 and 40-80 Hz compared with the N group. The MI-VT(+) group had significantly smaller maximal values in the frequency ranges of 40-80 and 80-150 Hz than the MI-VT(-) group. These three groups were clearly differentiated by the maximal values of the 40-80-Hz QRS area map. It was suggested that the maximal value of the 40-80-Hz QRS area map was a new marker for VT after anterior MI.

Impact of land use changes on surface feedbacks in sudanian region of West Africa

NASA Astrophysics Data System (ADS)

Cohard, J. M.; Galle, S.; Mamadou, O.; Peugeot, C.; Seghieri, J.; Kounouhewa, B.; Awanou, N. C.

2014-12-01

In West Africa, surface atmosphere exchanges have been found to impact both regional and local features of the Monsoon. At local scale the spatial patterns of Evaporative Fraction can drive the trajectories of mesoscale convective systems. Under Sudanian climate a mean of ~80% of the precipitation return to atmosphere through evapotranspiration but this important amount and its dynamics may vary with the vegetation cover. In consequence, any land use or climate changes can lead to modifications on the surface feedbacks and thus on both the atmospheric and the continental water cycle. In West Africa, Sudanian regions are submitted to a ~3% demographical increase per year, which leads to regular deforestation to the benefit of cultivated areas. This study aims at quantifying the changes in evapotranspiration regime caused by such a land use change under Sudanian climate. Within the framework of The AMMA-CATCH observatory, energy and water vapor fluxes were investigated in west Africa since 2007. Herein, a pluri-annual (2007 - 2010) energy budget of a clear forest and a cultivated area located in northern Benin are analysed. Results show that evapotranspiration rates over the sudanian forest are higher than those of cultivated area, because of agricultural practice and water availability for trees. After harvest, the residual vegetation is burned to bring nutriment to soil and to clean the landscape around the villages. Thus, during the dry season, the cultivated areas are bare. At the same time, a significant evapotranspiration is measured over the forest area despite the lack of precipitations. The deep root system of such vegetation allow the trees to get access to water during the dry season. During the rainy season, a significant difference in evapotransiration rates are also observed. These differences lead to a large deficit of water vapor that returns to the atmosphere and will significantly change the continental water cycle when forests will be replaced by cultivated areas

Computer-aided analysis of LANDSAT data for surveying Texas coastal zone environments. [Pass Cavallo and Port O'Conner

NASA Technical Reports Server (NTRS)

Kristof, S. J. (Principal Investigator); Weismiller, R. A.

1977-01-01

The author has identified the following significant results. The study areas were Pass Cavallo and Port O'Connor. The following terrestrial and aquatic environments were discriminated: alternating beach ridges, swales, sand dunes, beach birms, deflation surfaces, land-water interface, urban, spoil areas, fresh and salt water marshes, grass and woodland, recently burned or grazed areas, submerged vegetation, and waterways.

Feasibility of high recovery highwall mining equipment. Final report

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

Not Available

1981-01-01

Three equipment systems exhibited significant promise: the RSV Miner, a surface longwall using standard underground equipment, and the variable angle auger. Other equipment systems showing considerable merit were the surface shortwall, and the two extended depth augers. Of the three most significant systems, the RSV Miner exhibits the greatest versatility and adaptability. It may be used competently in many surface mining applications and readily adapts to geologic anomalies and changing seam heights. The machine employs steering and guidance equipment and provides the necessary capabilities for extended depth operation. Safety is good, as no men are required to work underground. However,more » most important is the system's recovery factor of approximately 75% to 80% of the in-situ coal reserve within reach. The surface longwall system using standard underground equipment (preferably a ranging drum shearer in conjunction with shield supports) is most suited to either a trench mining or a modified area mining application. Both applications would allow the length of the face to be held constant. Another important consideration is legal requirements for a tailgate entry, which would necessitate additional equipment for development in a modified area mining application. When compared to surface shortwall, surface longwall exhibits higher productivity, a far greater equipment selection which allows system tailoring to geologic conditions, and greater roof control due to the significantly smaller section of overburden that must be supported. Recovery should approach, and possibly exceed, 90% of the coal in-place. The variable angle auger, which is currently only a concept, fills a very real need for which no other equipment is available at this time.« less

Simulation of Urban Rainfall-Runoff in Piedmont Cities: A Case Study in Jinan City, China

NASA Astrophysics Data System (ADS)

Chang, X.; Xu, Z.; Zhao, G.; Li, H.

2017-12-01

During the past decades, frequent flooding disasters in urban areas resulted in catastrophic impacts such as human life casualties and property damages especially in piedmont cities due to its specific topography. In this study, a piedmont urban flooding model was developed in the Huangtaiqiao catchment based on SWMM. The sub-catchments in this piedmont area were divided into mountainous area, plain area and main urban area according to the variations of underlying surface topography. The impact of different routing mode and channel roughness on simulation results was quantitatively analyzed under different types of scenarios, and genetic algorithm was used to optimize model parameters. Results show that the simulation is poor (with a mean Nash coefficient of 0.61) when using the traditional routing mode in SWMM model, which usually ignores terrain variance in piedmont area. However, when the difference of routing mode, percent routed and channel roughness are considered, the prediction precision of model were significantly increased (with a mean Nash coefficient of 0.86), indicating that the difference of surface topography significantly affects the simulation results in piedmont cities. The relevant results would provide the scientific basis and technical support for rainfall-runoff simulation, flood control and disaster alleviation in piedmont cities.

The thermal stability and catalytic application of manganese oxide-zirconium oxide powders

NASA Astrophysics Data System (ADS)

Zhao, Qiang

MnOx-ZrO2 mixed oxide is an active catalyst for combustion, oxidation, and oxygen storage applications. MnOx-ZrO 2 mixture also has large reversible adsorption capability for NO x, which makes it a promising candidate for NOx abatement in automobile emission control. However, MnOx-ZrO 2 mixed oxide has not been used extensively because the processing and the thermal stability of resulting powders have not been studied systematically. It is critical to have thermally stable catalytic material because the application temperature can reach as high as 1000°C during service. In this study, we focused on improving the thermal stability of oxide powders, such as MnO x, ZrO2, and MnOx-ZrO2, by controlling the processing methods and parameters. For pure MnOx made from the precipitation method using Mn(NO3)2 aqueous solution and ammonium hydroxide, we found that lower concentration of Mn(NO3) 2 solution and larger amount of ammonium hydroxide resulted in higher surface area powders. For pure ZrO2, we found curing hydrous zirconia in the mother liquid produced ZrO2 powders with larger pore volume and pore size. The specific surface area was also significantly enhanced by curing for the synthesized powders before calcination or after low temperature calcinations, and this improvement could be preserved to high temperatures if SiO2 was doped in ZrO2. A Monte Carlo simulation model examining the effect of primary particle packing on the specific surface area was used to explain the curing result. MnOx-ZrO2 mixtures had higher surface area than the single component oxide at 500 and 700°C because composite powders sintered less. The sintering behavior of composite powders at 900°C was opposite to that at 500°C and the specific surface area of MnOx-ZrO2 decreased drastically at 900°C. Curing ZrO2 first or using La dopant could significantly enhance the specific surface area of MnOx-ZrO2 at 900°C. Through the tests of the redox property and NO storage capability we found a close relationship between the enhanced thermal stability and better catalytic performance.

Experimental investigation of edge hardening and edge cracking sensitivity of burr-free parts

NASA Astrophysics Data System (ADS)

Senn, Sergei; Liewald, Mathias

2018-05-01

This experimental study is focused on characterisation of edge hardening of sheet metal and remaining formability of differently prepared cutted edges. Edge cracking sensitivity of counter cutted, shear cutted, recutted and water-jet cutted components are compared and evaluated. Subsequently, edge hardening and hole expansion ratio were correlated for material HC420 LA with sheet thickness of t = 2 mm. As other studies show, the cutting edge surface quality influences the hole expansion ratio: a high clear cut surface increases formability of cutting edges, whereas micro cracks and rough surfaces result into a large fracture surface, which impact remaining formability noticeably. Thus, cutting edges with lower edge hardening behaviour in conjunction with a higher clear cut surface exhibit higher hole expansion ratios. Counter cutting and the recutting do show a similar effect on edge hardening. Using the hole expansion test, it was possible to prove that counter cutted components show a significantly lower edge cracking sensitivity in comparison to conventionally shear cutted components. The hole expansion ratio of counter cutted specimens looks balanced and is comparable to the hole expansion ratio measured from specimens with recutted or water jet cutted edges. The significant difference of the investigated cutting processes is characterized by size of clear cutting area. This area of recutted edges emerges larger than the area of counter cutted specimens, which evidently leads to an increased hole expansion ratio of recutted specimens compared to conventionally shear cutted ones. However, it is important to note that the hole expansion ratio of counter cutted and recutted specimens appear fairly balanced, but counter cutted samples indeed can be produced burr-free. Using counter cutting technology, it is possible to produce burr free surfaces with high edge formability.

Carbon nanotubes: properties, synthesis, purification, and medical applications

PubMed Central

2014-01-01

Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering. PMID:25170330

Carbon nanotubes: properties, synthesis, purification, and medical applications

NASA Astrophysics Data System (ADS)

Eatemadi, Ali; Daraee, Hadis; Karimkhanloo, Hamzeh; Kouhi, Mohammad; Zarghami, Nosratollah; Akbarzadeh, Abolfazl; Abasi, Mozhgan; Hanifehpour, Younes; Joo, Sang Woo

2014-08-01

Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering.

Carbon nanotubes: properties, synthesis, purification, and medical applications.

PubMed

Eatemadi, Ali; Daraee, Hadis; Karimkhanloo, Hamzeh; Kouhi, Mohammad; Zarghami, Nosratollah; Akbarzadeh, Abolfazl; Abasi, Mozhgan; Hanifehpour, Younes; Joo, Sang Woo

2014-01-01

Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering.

Temporal changes in surface roughness around 88°S from repeat high-resolution Airborne Topographic Mapper laser altimetry

NASA Astrophysics Data System (ADS)

Studinger, M.; Brunt, K. M.; Medley, B.; Casey, K.; Neumann, T.

2017-12-01

The southern convergence of all ICESat-2 and CryoSat-2 tracks at 88°S is in a region of relatively low accumulation and surface slope making it ideal for satellite altimetry calibration and validation. In order to evaluate the stability and surface characteristics of the area we have analyzed repeat airborne laser altimetry measurements acquired around 88°S during 2014 and 2016 by NASA's Airborne Topographic Mapper (ATM) as part of Operation IceBridge. ATM is a conical scanner that operates at a wavelength of 532 nm, with a footprint of 1 meter and a 250-m-wide swath on the ground. The ATM Level 2 ICESSN data product includes slope and roughness estimates in 80 m × 80 m platelets across the swath. The mean surface roughness around 88°S for the 2014 data is 9.4 ± 2.0 cm, with the repeat flights in 2016 showing 8.6 ± 2.8 cm. The 2014 data reveals several areas where surface roughness doubles over very short spatial scales of only a few hundred meters. These features are several tens of km wide and appear to be oriented parallel to the main sastrugi direction visible in ATM spot elevation data and Digital Mapping System (DMS) visual imagery collected simultaneously. The rougher surface features are also present in the CReSIS snow radar data collected at the same time. These areas of increased surface roughness disappear in 2016 or seem to be significantly reduced in amplitude with the sharpness of the edges significantly reduced. The combination of simultaneous altimetry, snow radar and visual imagery on a regional scale provides a unique data set to study small scale deposition and erosional processes and their temporal variability. Our long-term goal is to quantify the spatial variability in snow accumulation rates south of 86°S in support of past, current and future altimetry measurements and surface mass balance model evaluation.

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.

Thermal Imaging of Body Surface Temperature Distribution in Women with Anorexia Nervosa.

PubMed

Chudecka, Monika; Lubkowska, Anna

2016-01-01

The drastic reduction in body weight observed in anorexia nervosa (AN) leads to various endocrine changes and consequently to disturbance in thermoregulation mechanisms and body temperature. Thermography allows for a noninvasive diagnosis of the distribution of skin surface temperatures, which is especially important for difficult patients such as women with AN, who are often very sensitive and difficult to treat. The main aim of this study was to measure the mean temperatures (Tmean ) of selected body areas in young women diagnosed with AN and identify those areas where the temperature differences were particularly significant between healthy women and them. Additionally, we determined the relationships between body mass index, body composition (especially subcutaneous and VFM) and the value of mean surface temperature (Tmean ) in AN woman. In the subjects with AN, Tmean of the abdomen, lower back and thighs were significantly higher than in the reference group, while Tmean of the hands were significantly lower. Among other things, analysis showed a significant negative correlation between Tmean of the abdomen, lower back and thighs, and the mass of subcutaneous and visceral fat. The lower Tmean of the hand was directly proportional to the reduced anthropomorphic parameters. The direct evaluation of body surface temperature distribution could provide clinical implications for the treatment of anorexic patients, including the potential use of thermotherapy in stimulating the circulatory system, especially in hypothermia, bradycardia and hypotension. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.

Effect of topical epigallocatechin gallate on corneal neovascularization in rabbits.

PubMed

Koh, Chang Hyun; Lee, Hyun Soo; Chung, Sung Kun

2014-05-01

The aim of this study was to evaluate the efficacy of topical application of epigallocatechin gallate (EGCG) for the treatment of corneal neovascularization in a rabbit model. Corneal neovascularization was induced in 12 rabbits by placing a black silk suture in the corneal stroma (24 eyes) for a week. After suturing, 1 randomly chosen eye of the 12 rabbits was treated with topical EGCG at 2 different concentrations: 0.01% (group 1) and 0.1% (group 2), whereas the contralateral eyes were treated with sterilized balanced salt solution as the control. All eye drops were applied for 2 weeks after suturing. The suture materials were removed from all eyes on day 7. The surface area of corneal neovascularization was measured and analyzed in all eyes on days 7 and 14. On day 14, all eyes were extracted to measure the concentrations of vascular endothelial growth factor (VEGF) messenger RNA and cyclooxygenase-2 (COX-2) protein. The surface area of induced corneal neovascularization was significantly smaller only in group 2 compared with that of the control group on days 7 and 14 (P < 0.001). The change in surface area of corneal neovascularization after removal of the suture material was not significantly different between all 3 groups. VEGF messenger RNA levels were significantly lower in group 2 than in the control group (P < 0.001). The concentration of COX-2 was significantly lower in group 2 than in the control group (P = 0.043), but no significant difference was observed between group 1 and the control group. Topical administration of EGCG effectively inhibits corneal neovascularization in rabbits. This inhibitory effect is probably related to the suppression of VEGF and COX-2 meditated angiogenesis.

Seismic reflection characteristics of naturally-induced subsidence affecting transportation

USGS Publications Warehouse

Miller, R.D.; Xia, J.; Steeples, D.W.

2009-01-01

High-resolution seismic reflections have been used effectively to investigate sinkholes formed from the dissolution of a bedded salt unit found throughout most of Central Kansas. Surface subsidence can have devastating effects on transportation structures. Roads, rails, bridges, and pipelines can even be dramatically affected by minor ground instability. Areas susceptible to surface subsidence can put public safety at risk. Subsurface expressions significantly larger than surface depressions are consistently observed on seismic images recorded over sinkholes in Kansas. Until subsidence reaches the ground surface, failure appears to be controlled by compressional forces evidenced by faults with reverse orientation. Once a surface depression forms or dissolution of the salt slows or stops, subsidence structures are consistent with a tensional stress environment with prevalent normal faults. Detecting areas of rapid subsidence potential, prior to surface failure, is the ultimate goal of any geotechnical survey where the ground surface is susceptible to settling. Seismic reflection images have helped correlate active subsidence to dormant paleofeatures, project horizontal growth of active sinkholes based on subsurface structures, and appraise the risk of catastrophic failure. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.

Influence of Substrate Bonding and Surface Morphology on Dynamic Organic Layer Growth: Perylenetetracarboxylic Dianhydride on Au(111).

PubMed

Schmidt, Thomas; Marchetto, Helder; Groh, Ullrich; Fink, Rainer H; Freund, Hans-Joachim; Umbach, Eberhard

2018-05-15

We investigated the dynamics of the initial growth of the first epitaxial layers of perylenetetracarboxylic dianhydride (PTCDA) on the Au(111) surface with high lateral resolution using the aberration-corrected spectro-microscope SMART. With this instrument, we could simultaneously study the different adsorption behaviors and layer growth on various surface areas consisting of either a distribution of flat (111) terraces, separated by single atomic steps ("ideal surface"), or on areas with a high density of step bunches and defects ("realistic surface"). The combined use of photoemission electron microscopy, low-energy electron microscopy, and μ-spot X-ray absorption provided a wealth of new information, showing that the growth of the archetype molecule PTCDA not only has similarities but also has significant differences when comparing Au(111) and Ag(111) substrate surfaces. For instance, under otherwise identical preparation conditions, we observed different growth mechanisms on different surface regions, depending on the density of step bunches. In addition, we studied the spatially resolved desorption behavior which also depends on the substrate morphology.

Freshwater molluscs as indicators of bioavailability and toxicity of metals in surface-water systems

USGS Publications Warehouse

Elder, John F.; Collins, Jerilyn J.; Ware, George W.

1991-01-01

During the past several decades, studies from a variety of locations have demonstrated widespread occurrence of metals in surface waters at concentrations significantly higher than background levels. Elevated concentrations are not limited to certain water types or polluted areas; they appear in all types of systems and in all geographic areas. It is clear that metals enter the aquatic systems from diverse sources, both point and nonpoint, and they can be readily transported from one system to another. Transport routes include atmospheric, terrestrial, subterranean, aquatic, and biological pathways (Elder 1988; Salomons and Forstner 1984).

[The design and implementation of the web typical surface object spectral information system in arid areas based on .NET and SuperMap].

PubMed

Xia, Jun; Tashpolat, Tiyip; Zhang, Fei; Ji, Hong-jiang

2011-07-01

The characteristic of object spectrum is not only the base of the quantification analysis of remote sensing, but also the main content of the basic research of remote sensing. The typical surface object spectral database in arid areas oasis is of great significance for applied research on remote sensing in soil salinization. In the present paper, the authors took the Ugan-Kuqa River Delta Oasis as an example, unified .NET and the SuperMap platform with SQL Server database stored data, used the B/S pattern and the C# language to design and develop the typical surface object spectral information system, and established the typical surface object spectral database according to the characteristics of arid areas oasis. The system implemented the classified storage and the management of typical surface object spectral information and the related attribute data of the study areas; this system also implemented visualized two-way query between the maps and attribute data, the drawings of the surface object spectral response curves and the processing of the derivative spectral data and its drawings. In addition, the system initially possessed a simple spectral data mining and analysis capabilities, and this advantage provided an efficient, reliable and convenient data management and application platform for the Ugan-Kuqa River Delta Oasis's follow-up study in soil salinization. Finally, It's easy to maintain, convinient for secondary development and practically operating in good condition.

Modelling Mean Albedo of Individual Roofs in Complex Urban Areas Using Satellite Images and Airborne Laser Scanning Point Clouds

NASA Astrophysics Data System (ADS)

Kalantar, B.; Mansor, S.; Khuzaimah, Z.; Sameen, M. Ibrahim; Pradhan, B.

2017-09-01

Knowledge of surface albedo at individual roof scale is important for mitigating urban heat islands and understanding urban climate change. This study presents a method for quantifying surface albedo of individual roofs in a complex urban area using the integration of Landsat 8 and airborne LiDAR data. First, individual roofs were extracted from airborne LiDAR data and orthophotos using optimized segmentation and supervised object based image analysis (OBIA). Support vector machine (SVM) was used as a classifier in OBIA process for extracting individual roofs. The user-defined parameters required in SVM classifier were selected using v-fold cross validation method. After that, surface albedo was calculated for each individual roof from Landsat images. Finally, thematic maps of mean surface albedo of individual roofs were generated in GIS and the results were discussed. Results showed that the study area is covered by 35% of buildings varying in roofing material types and conditions. The calculated surface albedo of buildings ranged from 0.16 to 0.65 in the study area. More importantly, the results indicated that the types and conditions of roofing materials significantly effect on the mean value of surface albedo. Mean albedo of new concrete, old concrete, new steel, and old steel were found to be equal to 0.38, 0.26, 0.51, and 0.44 respectively. Replacing old roofing materials with new ones should highly prioritized.

[Effects of tree species diversity on fine-root biomass and morphological characteristics in subtropical Castanopsis carlesii forests].

PubMed

Wang, Wei-Wei; Huang, Jin-Xue; Chen, Feng; Xiong, De-Cheng; Lu, Zheng-Li; Huang, Chao-Chao; Yang, Zhi-Jie; Chen, Guang-Shui

2014-02-01

Fine roots in the Castanopsis carlesii plantation forest (MZ), the secondary forest of C. carlesii through natural regeneration with anthropogenic promotion (AR), and the secondary forest of C. carlesii through natural regeneration (NR) in Sanming City, Fujian Province, were estimated by soil core method to determine the influence of tree species diversity on biomass, vertical distribution and morphological characteristics of fine roots. The results showed that fine root biomass for the 0-80 cm soil layer in the MZ, AR and NR were (182.46 +/- 10.81), (242.73 +/- 17.85) and (353.11 +/- 16.46) g x m(-2), respectively, showing an increased tendency with increasing tree species diversity. In the three forests, fine root biomass was significantly influenced by soil depth, and fine roots at the 0-10 cm soil layer accounted for more than 35% of the total fine root biomass. However, the interaction of stand type and soil depth on fine-root distribution was not significant, indicating no influence of tree species diversity on spatial niche segregation in fine roots. Root surface area density and root length density were the highest in NR and lowest in the MZ. Specific root length was in the order of AR > MZ > NR, while specific root surface area was in the order of NR > MZ > AR. There was no significant interaction of stand type and soil depth on specific root length and specific root surface area. Fine root morphological plasticity at the stand level had no significant response to tree species diversity.

The use of LANDSAT imagery in relation to air survey imagery for terrain analysis in northwest Queensland, Australia, volume 1

NASA Technical Reports Server (NTRS)

Cole, M. M.; Owen-Jones, E. S. (Principal Investigator)

1977-01-01

The author has identified the following significant results. Distinctive spectral signatures discriminated areas underlain by distinctive lithological/stratigraphical units where bedrock either outcrops or is relatively near to surface in the Lady Annie-Mt. Gordon fault zone, the Mary Kathleen, and Dugald River-Naraku areas. Spectral signatures associated with discrete plant communities distinguished different types of superficial deposits over the Cloncurry Plains. Distinctive spectral signatures also revealed the presence and nature of concealed bedrock beneath cover of residuum and superficial deposits where this is relatively thin in the Cloncurry Plains. Major faults were clearly displayed in areas of outcropping and near surface bedrock. Sets of lineaments with preferred orientations were identified in the Lady Annie and Dugald River areas. Known base metal deposits occur along these features.

Exploring the Influence of Impervious Surface Density and Shape on Urban Heat Islands in the Northeast USA Using MODIS and Landsat

NASA Technical Reports Server (NTRS)

Zhang, Ping; Imhoff, Marc L.; Bounoua, Lahouri; Wolfe, Robert E.

2011-01-01

Impervious surface area (ISA) from the National Land Cover Database (NLCD) 2001 and land surface temperature (LST) from MODIS averaged over three annual cycles (2003-2005) are used in a spatial analysis to assess the urban heat island (UHI) signature and its relationship to settlement size and shape, development intensity distribution, and land cover composition for 42 urban settlements embedded in forest biomes in the Northeastern United States. Development intensity zones, based on percent ISA, are defined for each urban area emanating outward from the urban core to nearby rural areas and are used to stratify land surface temperature. The stratification is further constrained by biome type and elevation to insure objective intercomparisons between urban zones within an urban settlement and between settlements. Stratification based on ISA allows the definition of hierarchically ordered urban zones that are consistent across urban settlements and scales. In addition to the surrounding ecological context, we find that the settlement size and shape as well as the development intensity distribution significantly influence the amplitude of summer daytime UHI. Within the Northeastern US temperate broadleaf mixed forest, UHI magnitude is positively related to the logarithm of the urban area size. Our study indicates that for similar urban area sizes, the development intensity distribution is one of the major drivers of UHI. In addition to urban area size and development intensity distribution, this analysis shows that both the shape of the urban area and the land cover composition in the surrounding rural area play an important role in modulating the UHI magnitude in different urban settlements. Our results indicate that remotely sensed urban area size and shape as well as the development intensity distribution influence UHI amplitude across regional scales.

Water quality impacts of forest fires

Treesearch

Tecle Aregai; Daniel Neary

2015-01-01

Forest fires have been serious menace, many times resulting in tremendous economic, cultural and ecological damage to many parts of the United States. One particular area that has been significantly affected is the water quality of streams and lakes in the water thirsty southwestern United States. This is because the surface water coming off burned areas has resulted...

Clinical relevance of pre-ovulatory follicular temperature in heat-stressed lactating dairy cows.

PubMed

López-Gatius, F; Hunter, Rhf

2017-06-01

Temperature gradients in female reproductive tissues seem to influence the success of key processes such as ovulation and fertilization. The objective of this study was to investigate whether pre-ovulatory follicles are cooler than neighbouring uterine tissue and deep rectal temperatures in lactating dairy cows under heat stress conditions. Temperatures within the pre-ovulatory follicle, on the uterine adjacent surface and 20 cm deep within rectum, were measured using fine thermistor probes within 45 min after sunrise (dawn). Cows were selected from synchronized groups for fixed-time insemination during the warm period of the year. Five cows under direct sun radiation and 11 cows in the shade were included in the study. None of the cows in the sun area ovulated within 24 hr, whereas 10 of the 11 cows in the sun area ovulated. Four of the 10 ovulating cows became pregnant. In the ovulating cows, follicular temperatures were 0.74 and 1.54°C significantly cooler than uterine surface and rectal temperatures, respectively, whereas temperatures in the uterine area were 0.80°C significantly cooler than rectal temperatures. No significant differences among temperatures were found in non-ovulating cows. Follicular size was similar for ovulating and non-ovulating cows. Environmental temperatures in the shade area were 6.4°C significantly lower than those in the sun area. Results of this study indicate that pre-ovulatory follicles are cooler than neighbouring uterine tissue and deep rectal temperatures and those temperature gradients were not found in cows suffering ovulation failure. © 2017 Blackwell Verlag GmbH.

Ground and surface water developmental toxicity at a municipal landfill--Description and weather-related variation

USGS Publications Warehouse

Bruner, M.A.; Rao, M.; Dumont, J.N.; Hull, M.; Jones, T.; Bantle, J.A.

1998-01-01

Contaminated groundwater poses a significant health hazard and may also impact wildlife such as amphibians when it surfaces. Using FETAX (Frog Embryo Teratogenesis Assay-Xenopus), the developmental toxicity of ground and surface water samples near a closed municipal landfill at Norman, OK, were evaluated. The groundwater samples were taken from a network of wells in a shallow, unconfined aquifer downgradient from the landfill. Surface water samples were obtained from a pond and small stream adjacent to the landfill. Surface water samples from a reference site in similar habitat were also analyzed. Groundwater samples were highly toxic in the area near the landfill, indicating a plume of toxicants. Surface water samples from the landfill site demonstrated elevated developmental toxicity. This toxicity was temporally variable and was significantly correlated with weather conditions during the 3 days prior to sampling. Mortality was negatively correlated with cumulative rain and relative humidity. Mortality was positively correlated with solar radiation and net radiation. No significant correlations were observed between mortality and weather parameters for days 4–7 preceding sampling.

Adsorption and desorption of carbaryl on hexadecyl trimethyl ammonium bromide modified zeolite NaY using RGB portable photometer

NASA Astrophysics Data System (ADS)

Patdhanagul, Nopbhasinthu; Chanpaka, Saiphon; Intharaksa, Orapan; Sirival, Rujikarn; Thanomsith, Kannikar; Wongkwanklom, Sarayuth

2018-04-01

The carbaryl adsorption-desorption isotherms of zeolite NaY and hexadecyl trimethyl ammonium bromide (HTAB) modified zeolite NaY were investigated. Zeolite NaY was synthesized and modified by HTAB in the concentration range 0.1 - 10.0 mM. The adsorption isotherms indicated that zeolite modified with HTAB could significantly enhance the carbaryl adsorption capacity. Zeolite NaY modified with 5.0 mM HTAB gave great carbaryl adsorption because of hydrophilic surface. The 5.0 mM HTAB could adsorb up to 145.75 ppm g-1 of carbaryl which was equivalent to a 36.7% increase. The Surface area characterization showed the remaining of pore volume and pore size diameter and external surface area whereas the BET surface area and micropore surface area of modified zeolite slightly decreased. The XRD results indicate that modification of zeolite NaY with HTAB does not change the crystallinity of the starting zeolite. The elemental analysis indicated that the Si/Al ratio of synthesized zeolite NaY was close to 2.43. Desorption of carbaryl was tested by organic solvents such as methanol, ethanol, tetrahydrofuran, hexane and Deionized water. The results demonstrated that the percentage desorption of methanol is the highest. Carbaryl was quantitatively desorbed with percentage desorption of 82-100 %. It indicated sorption mechanism of carbaryl on the modified sorbent which was principally driven by hydrophobic forces.

Mapping Surface Cover Parameters Using Aggregation Rules and Remotely Sensed Cover Classes. Version 1.9

NASA Technical Reports Server (NTRS)

Arain, Altaf M.; Shuttleworth, W. James; Yang, Z-Liang; Michaud, Jene; Dolman, Johannes

1997-01-01

A coupled model, which combines the Biosphere-Atmosphere Transfer Scheme (BATS) with an advanced atmospheric boundary-layer model, was used to validate hypothetical aggregation rules for BATS-specific surface cover parameters. The model was initialized and tested with observations from the Anglo-Brazilian Amazonian Climate Observational Study and used to simulate surface fluxes for rain forest and pasture mixes at a site near Manaus in Brazil. The aggregation rules are shown to estimate parameters which give area-average surface fluxes similar to those calculated with explicit representation of forest and pasture patches for a range of meteorological and surface conditions relevant to this site, but the agreement deteriorates somewhat when there are large patch-to-patch differences in soil moisture. The aggregation rules, validated as above, were then applied to remotely sensed 1 km land cover data set to obtain grid-average values of BATS vegetation parameters for 2.8 deg x 2.8 deg and 1 deg x 1 deg grids within the conterminous United States. There are significant differences in key vegetation parameters (aerodynamic roughness length, albedo, leaf area index, and stomatal resistance) when aggregate parameters are compared to parameters for the single, dominant cover within the grid. However, the surface energy fluxes calculated by stand-alone BATS with the 2-year forcing, data from the International Satellite Land Surface Climatology Project (ISLSCP) CDROM were reasonably similar using aggregate-vegetation parameters and dominant-cover parameters, but there were some significant differences, particularly in the western USA.

Surface modification technologies using concentrated solar radiation

NASA Astrophysics Data System (ADS)

Pitts, J. Roland; Stanley, J. T.; Tracy, Ed; Fields, C. L.

Research conducted at the Solar Energy Research Institute (SERI) during the past three years addressed a number of the critical areas and has explored the possibility of using highly concentrated solar radiation to induce beneficial surface transformation. The principal goal is to develop new coatings and processes that improve the performance and lifetime of materials at reduced processing costs. Highly concentrated radiant energy provides a controllable means of delivering large flux densities to solid surfaces, where the resulting thermal energy can cause phase changes, atomic migrations, and chemical reactions on a surface without greatly perturbing the bulk properties; alternatively, the photons may directly interact with species on the surface. These changes may result in improved properties of the materials by making the surface harder, more resistant to corrosion or wear, thermally resistant, or with lower coefficients of friction. In a solar furnace, this flux can be delivered in large quantities over large areas, or it can be tailored to match the demands of a particular process. Furthermore, this occurs without the environmental liability associated with providing power to more conventional light sources. Recent work at SERI has used fluxes in the range from 100 to 250 w/sq cm for inducing such beneficial surface transformations. Significant results have been obtained in the area of phase transformation hardening of steels and melting powders and preapplied coatings to form fully dense, well-bonded coatings on the surface. New directions in coating technology using highly concentrated solar beams to induce chemical vapor deposition processes are described. Application areas that have not been researched in detail but would appear to be good matches to the solar technology are also reviewed.

Response of water temperatures and stratification to changing climate in three lakes with different morphometry

NASA Astrophysics Data System (ADS)

Magee, Madeline R.; Wu, Chin H.

2017-12-01

Water temperatures and stratification are important drivers for ecological and water quality processes within lake systems, and changes in these with increases in air temperature and changes to wind speeds may have significant ecological consequences. To properly manage these systems under changing climate, it is important to understand the effects of increasing air temperatures and wind speed changes in lakes of different depths and surface areas. In this study, we simulate three lakes that vary in depth and surface area to elucidate the effects of the observed increasing air temperatures and decreasing wind speeds on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes) over a century (1911-2014). For all three lakes, simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, stability increased, and longwave and sensible heat fluxes at the surface increased. Overall, lake depth influences the presence of stratification, Schmidt stability, and differences in surface heat flux, while lake surface area influences differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates. Larger surface area lakes have greater wind mixing due to increased surface momentum. Climate perturbations indicate that our larger study lakes have more variability in temperature and stratification variables than the smaller lakes, and this variability increases with larger wind speeds. For all study lakes, Pearson correlations and climate perturbation scenarios indicate that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature, and wind can act to either amplify or mitigate the effect of warmer air temperatures on lake thermal structure depending on the direction of local wind speed changes.

Slope-area thresholds of road-induced gully erosion and consequent hillslope-channel interactions

Treesearch

Harry Alexander Katz; J. Michael Daniels; Sandra Ryan-Burkett

2014-01-01

Pikes Peak Highway is a partially paved road between Cascade, Colorado and the summit of Pikes Peak. Significant gully erosion is occurring on the hillslopes due to the concentration of surface runoff, the rearrangement of drainage pathways along the road surface and adjacent drainage ditches, and the high erodibility of weathered Pikes Peak granite that underlies the...

Highlighting the relative effects of surface characteristics and porosity on CO2 capture by adsorbents templated from melamine-based polyaminals

NASA Astrophysics Data System (ADS)

Rehman, Adeela; Park, Soo-Jin

2018-02-01

Heteroatom doping along with well-tuned porosity are considered as significant characteristics of a porous carbon material for various potential applications. However, it is a challenging task to tune a single parameter while retaining the other variables unaffected, and this is considered a limiting factor in rational and systematic research. In the present work, in situ nitrogen-enriched microporous carbon materials were prepared by direct carbonization of conjugated porous polyaminals at two different temperatures. To evaluate the role of nitrogen doping in gas adsorption, a comparison was made with commercially available high-surface-area (2093 m2/g) microporous petroleum-pitch-based activated carbon (AC) deprived of nitrogen functionalities. It was found that the CO2 adsorption capacity of MPA-2-700, carbonized melamine based polyaminal at 700 °C, (186.1 mg/g at 273 K/1 bar with a surface area of 403 m2/g) was significantly higher than that of AC (111.0 mg/g at 273 K/1 bar). Our results present valuable insight into designing porous adsorbents with optimized surface polarity and textural characteristics as promising candidates for CO2 capture.

Mapping inter-annual dynamics of open surface water bodies in Oklahoma from Landsat images in 1984 to 2015 at 30-m spatial resolution

NASA Astrophysics Data System (ADS)

Zou, Z.; Xiao, X.; Menarguez, M.; Dong, J.; Qin, Y.

2016-12-01

Open surface water bodies are important water resource for public supply, irrigation, livestock, and wildlife in Oklahoma. The inter-annual variation of Oklahoma water bodies directly affect the water availability for public supply, irrigation and cattle industry. In this study, tens of thousands of Landsat TM/ETM+ images from 1984 to 2015 were used to track the dynamics of open surface water bodies. Both water-related spectral indices and vegetation indices were used to map water bodies for individual images. The resultant maps show that Oklahoma year-long open surface water bodies varied significantly over the last 32 years, with an average annual water body area equals to 2300 km2, accounting for 1.27 % of the Oklahoma state area (181,037 km2). 4.3 million year-long water body pixels were detected in the 32-year accumulated water frequency map, corresponding to 3100 km2. Only 45% ( 1400 km2) of the those pixels had water throughout the 32 years, while the rest 55% pixels had a dry-up period. The smaller water bodies have a higher risk to dry up and a lower probability to have water throughout the years. Drought years could significantly decrease the number of small water bodies and shrink the area of large water bodies, while pluvial years could create large number of small seasonal water bodies. The significant influencing factors of current year water bodies include the precipitation and temperature of current year and the water body condition of the previous year. This water body dynamics study could be used to support water resource management, crop and livestock production, and biodiversity conservation in Oklahoma.

Carbon-climate feedbacks accelerate ocean acidification

NASA Astrophysics Data System (ADS)

Matear, Richard J.; Lenton, Andrew

2018-03-01

Carbon-climate feedbacks have the potential to significantly impact the future climate by altering atmospheric CO2 concentrations (Zaehle et al. 2010). By modifying the future atmospheric CO2 concentrations, the carbon-climate feedbacks will also influence the future ocean acidification trajectory. Here, we use the CO2 emissions scenarios from four representative concentration pathways (RCPs) with an Earth system model to project the future trajectories of ocean acidification with the inclusion of carbon-climate feedbacks. We show that simulated carbon-climate feedbacks can significantly impact the onset of undersaturated aragonite conditions in the Southern and Arctic oceans, the suitable habitat for tropical coral and the deepwater saturation states. Under the high-emissions scenarios (RCP8.5 and RCP6), the carbon-climate feedbacks advance the onset of surface water under saturation and the decline in suitable coral reef habitat by a decade or more. The impacts of the carbon-climate feedbacks are most significant for the medium- (RCP4.5) and low-emissions (RCP2.6) scenarios. For the RCP4.5 scenario, by 2100 the carbon-climate feedbacks nearly double the area of surface water undersaturated with respect to aragonite and reduce by 50 % the surface water suitable for coral reefs. For the RCP2.6 scenario, by 2100 the carbon-climate feedbacks reduce the area suitable for coral reefs by 40 % and increase the area of undersaturated surface water by 20 %. The sensitivity of ocean acidification to the carbon-climate feedbacks in the low to medium emission scenarios is important because recent CO2 emission reduction commitments are trying to transition emissions to such a scenario. Our study highlights the need to better characterise the carbon-climate feedbacks and ensure we do not underestimate the projected ocean acidification.

Epidermal Permeability Barrier Recovery Is Delayed in Vitiligo-Involved Sites

PubMed Central

Liu, J.; Man, W.Y.; Lv, C.Z.; Song, S.P.; Shi, Y.J.; Elias, P.M.; Man, M.Q.

2010-01-01

Background/Objectives Prior studies have demonstrated that both the skin surface pH and epidermal permeability barrier function vary with skin pigmentation types. Although melanin deficiency is the main feature of vitiligo, alterations in cutaneous biophysical properties in vitiligo have not yet been well defined. In the present study, stratum corneum (SC) hydration, the skin surface pH and epidermal permeability barrier function in vitiligo were evaluated. Methods A total of 30 volunteers with vitiligo comprising 19 males and 11 females aged 13–51 years (mean age: 27.91 ± 2.06 years) were enrolled in this study. The skin surface pH, SC hydration, melanin/erythema index and transepidermal water loss (TEWL) were measured by respective probes connected to a Courage-Khazaka MPA5. SC integrity was determined by measuring the TEWL following each D-Squame application. The barrier recovery rate was assessed at 5 h following barrier disruption by repeated tape stripping. Results In addition to SC hydration, both melanin and erythema index were significantly lower in vitiligo lesions than in contralateral, nonlesional sites, while no difference in skin surface pH between vitiligo-involved and uninvolved areas was observed. In addition, neither the basal TEWL nor SC integrity in the involved areas differed significantly from that in the uninvolved areas. However, barrier recovery in vitiligo-involved sites was significantly delayed in comparison with uninvolved sites (40.83 ± 5.39% vs. 58.30 ± 4.71%; t = 2.441; p < 0.02). Conclusion Barrier recovery following tape stripping of the SC is delayed in vitiligo. Therefore, improvement in epidermal permeability barrier function may be an important unrecognized factor to be considered in treating patients with vitiligo. PMID:20185976

Evaluation of urban surface parameterizations in the WRF model using measurements during the Texas Air Quality Study 2006 field campaign

NASA Astrophysics Data System (ADS)

Lee, S.-H.; Kim, S.-W.; Angevine, W. M.; Bianco, L.; McKeen, S. A.; Senff, C. J.; Trainer, M.; Tucker, S. C.; Zamora, R. J.

2011-03-01

The performance of different urban surface parameterizations in the WRF (Weather Research and Forecasting) in simulating urban boundary layer (UBL) was investigated using extensive measurements during the Texas Air Quality Study 2006 field campaign. The extensive field measurements collected on surface (meteorological, wind profiler, energy balance flux) sites, a research aircraft, and a research vessel characterized 3-dimensional atmospheric boundary layer structures over the Houston-Galveston Bay area, providing a unique opportunity for the evaluation of the physical parameterizations. The model simulations were performed over the Houston metropolitan area for a summertime period (12-17 August) using a bulk urban parameterization in the Noah land surface model (original LSM), a modified LSM, and a single-layer urban canopy model (UCM). The UCM simulation compared quite well with the observations over the Houston urban areas, reducing the systematic model biases in the original LSM simulation by 1-2 °C in near-surface air temperature and by 200-400 m in UBL height, on average. A more realistic turbulent (sensible and latent heat) energy partitioning contributed to the improvements in the UCM simulation. The original LSM significantly overestimated the sensible heat flux (~200 W m-2) over the urban areas, resulting in warmer and higher UBL. The modified LSM slightly reduced warm and high biases in near-surface air temperature (0.5-1 °C) and UBL height (~100 m) as a result of the effects of urban vegetation. The relatively strong thermal contrast between the Houston area and the water bodies (Galveston Bay and the Gulf of Mexico) in the LSM simulations enhanced the sea/bay breezes, but the model performance in predicting local wind fields was similar among the simulations in terms of statistical evaluations. These results suggest that a proper surface representation (e.g. urban vegetation, surface morphology) and explicit parameterizations of urban physical processes are required for accurate urban atmospheric numerical modeling.

Percolation characteristics of solvent invasion in rough fractures under miscible conditions

NASA Astrophysics Data System (ADS)

Korfanta, M.; Babadagli, T.; Develi, K.

2017-10-01

Surface roughness and flow rate effects on the solvent transport under miscible conditions in a single fracture are studied. Surface replicas of seven different rocks (marble, granite, and limestone) are used to represent different surface roughness characteristics each described by different mathematical models including three fractal dimensions. Distribution of dyed solvent is investigated at various flow rate conditions to clarify the effect of roughness on convective and diffusive mixing. After a qualitative analysis using comparative images of different rocks, the area covered by solvent with respect to time is determined to conduct a semi-quantitative analysis. In this exercise, two distinct zones are identified, namely the straight lines obtained for convective (early times) and diffusive (late times) flow. The bending point between these two lines is used to point the transition between the two zones. Finally, the slopes of the straight lines and the bending points are correlated to five different roughness parameters and the rate (Peclet number). It is observed that both surface roughness and flow rate have significant effect on solvent spatial distribution. The largest area covered is obtained at moderate flow rates and hence not only the average surface roughness characteristic is important, but coessentially total fracture surface area needs to be considered when evaluating fluid distribution. It is also noted that the rate effect is critically different for the fracture samples of large grain size (marbles and granite) compared to smaller grain sizes (limestones). Variogram fractal dimension exhibits the strongest correlation with the maximum area covered by solvent, and display increasing trend at the moderate flow rates. Equations with variogram surface fractal dimension in combination with any other surface fractal parameter coupled with Peclet number can be used to predict maximum area covered by solvent in a single fracture, which in turn can be utilized to model oil recovery, waste disposal, and groundwater contamination processes in the presence of fractures.

Effect of electrode contact area on the information content of the recorded electrogastrograms: An analysis based on Rényi entropy and Teager-Kaiser Energy

NASA Astrophysics Data System (ADS)

Alagumariappan, Paramasivam; Krishnamurthy, Kamalanand; Kandiah, Sundravadivelu; Ponnuswamy, Mannar Jawahar

2017-06-01

Electrogastrograms (EGG) are electrical signals originating from the digestive system, which are closely correlated with its mechanical activity. Electrogastrography is an efficient non-invasive method for examining the physiological and pathological states of the human digestive system. There are several factors such as fat conductivity, abdominal thickness, change in electrode surface area etc, which affects the quality of the recorded EGG signals. In this work, the effect of variations in the contact area of surface electrodes on the information content of the measured electrogastrograms is analyzed using Rényi entropy and Teager-Kaiser Energy (TKE). Two different circular cutaneous electrodes with approximate contact areas of 201.14 mm2 and 283.64 mm2, have been adopted and EGG signals were acquired using the standard three electrode protocol. Further, the information content of the measured EGG signals were analyzed using the computed values of entropy and energy. Results demonstrate that the information content of the measured EGG signals increases by 6.72% for an increase in the contact area of the surface electrode by 29.09%. Further, it was observed that the average energy increases with increase in the contact surface area. This work appears to be of high clinical significance since the accurate measurement of EGG signals without loss in its information content, is highly useful for the design of diagnostic assistance tools for automated diagnosis and mass screening of digestive disorders.

Important photosynthetic contribution from the non-foliar green organs in cotton at the late growth stage.

PubMed

Hu, Yuan-Yuan; Zhang, Ya-Li; Luo, Hong-Hai; Li, Wei; Oguchi, Riichi; Fan, Da-Yong; Chow, Wah Soon; Zhang, Wang-Feng

2012-02-01

Non-foliar green organs are recognized as important carbon sources after leaves. However, the contribution of each organ to total yield has not been comprehensively studied in relation to the time-course of changes in surface area and photosynthetic activity of different organs at different growth stages. We studied the contribution of leaves, main stem, bracts and capsule wall in cotton by measuring their time-course of surface area development, O(2) evolution capacity and photosynthetic enzyme activity. Because of the early senescence of leaves, non-foliar organs increased their surface area up to 38.2% of total at late growth stage. Bracts and capsule wall showed less ontogenetic decrease in O(2) evolution capacity per area and photosynthetic enzyme activity than leaves at the late growth stage. The total capacity for O(2) evolution of stalks and bolls (bracts plus capsule wall) was 12.7 and 23.7% (total ca. 36.4%), respectively, as estimated by multiplying their surface area by their O(2) evolution capacity per area. We also kept the bolls (from 15 days after anthesis) or main stem (at the early full bolling stage) in darkness for comparison with non-darkened controls. Darkening the bolls and main stem reduced the boll weight by 24.1 and 9%, respectively, and the seed weight by 35.9 and 16.3%, respectively. We conclude that non-foliar organs significantly contribute to the yield at the late growth stage.

Trans-Membrane Area Asymmetry Controls the Shape of Cellular Organelles

PubMed Central

Beznoussenko, Galina V.; Pilyugin, Sergei S.; Geerts, Willie J. C.; Kozlov, Michael M.; Burger, Koert N. J.; Luini, Alberto; Derganc, Jure; Mironov, Alexander A.

2015-01-01

Membrane organelles often have complicated shapes and differ in their volume, surface area and membrane curvature. The ratio between the surface area of the cytosolic and luminal leaflets (trans-membrane area asymmetry (TAA)) determines the membrane curvature within different sites of the organelle. Thus, the shape of the organelle could be critically dependent on TAA. Here, using mathematical modeling and stereological measurements of TAA during fast transformation of organelle shapes, we present evidence that suggests that when organelle volume and surface area are constant, TAA can regulate transformation of the shape of the Golgi apparatus, endosomal multivesicular bodies, and microvilli of brush borders of kidney epithelial cells. Extraction of membrane curvature by small spheres, such as COPI-dependent vesicles within the Golgi (extraction of positive curvature), or by intraluminal vesicles within endosomes (extraction of negative curvature) controls the shape of these organelles. For instance, Golgi tubulation is critically dependent on the fusion of COPI vesicles with Golgi cisternae, and vice versa, for the extraction of membrane curvature into 50–60 nm vesicles, to induce transformation of Golgi tubules into cisternae. Also, formation of intraluminal ultra-small vesicles after fusion of endosomes allows equilibration of their TAA, volume and surface area. Finally, when microvilli of the brush border are broken into vesicles and microvilli fragments, TAA of these membranes remains the same as TAA of the microvilli. Thus, TAA has a significant role in transformation of organelle shape when other factors remain constant. PMID:25761238

Use of a Sampling Area-Adjusted Adenosine Triphosphate Bioluminescence Assay Based on Digital Image Quantification to Assess the Cleanliness of Hospital Surfaces.

PubMed

Ho, Yu-Huai; Wang, Lih-Shinn; Jiang, Hui-Li; Chang, Chih-Hui; Hsieh, Chia-Jung; Chang, Dan-Chi; Tu, Hsin-Yu; Chiu, Tan-Yun; Chao, Huei-Jen; Tseng, Chun-Chieh

2016-06-09

Contaminated surfaces play an important role in the transmission of pathogens. We sought to establish a criterion that could indicate "cleanliness" using a sampling area-adjusted adenosine triphosphate (ATP) assay. In the first phase of the study, target surfaces were selected for swab sampling before and after daily cleaning; then, an aerobic colony count (ACC) plate assay of bacteria and antibiotic-resistant bacteria was conducted. ATP swabs were also tested, and the ATP readings were reported as relative light units (RLUs). The results of the ACC and ATP assays were adjusted according to the sampling area. During the second phase of the study, a new cleaning process employing sodium dichloroisocyanurate (NaDCC) was implemented for comparison. Using the criterion of 2.5 colony-forming units (CFU)/cm², 45% of the sampled sites were successfully cleaned during phase one of the study. During phase two, the pass rates of the surface samples (64%) were significantly improved, except under stringent (5 RLU/cm²) and lax (500 RLU) ATP criteria. Using receiver-operating characteristic curve analysis, the best cut-off point for an area-adjusted ATP level was 7.34 RLU/cm², which corresponded to culture-assay levels of <2.5 CFU/cm². An area adjustment of the ATP assay improved the degree of correlation with the ACC-assay results from weak to moderate.

High-surface-area architectures for improved charge transfer kinetics at the dark electrode in dye-sensitized solar cells.

PubMed

Hoffeditz, William L; Katz, Michael J; Deria, Pravas; Martinson, Alex B F; Pellin, Michael J; Farha, Omar K; Hupp, Joseph T

2014-06-11

Dye-sensitized solar cell (DSC) redox shuttles other than triiodide/iodide have exhibited significantly higher charge transfer resistances at the dark electrode. This often results in poor fill factor, a severe detriment to device performance. Rather than moving to dark electrodes of untested materials that may have higher catalytic activity for specific shuttles, the surface area of platinum dark electrodes could be increased, improving the catalytic activity by simply presenting more catalyst to the shuttle solution. A new copper-based redox shuttle that experiences extremely high charge-transfer resistance at conventional Pt dark electrodes yields cells having fill-factors of less than 0.3. By replacing the standard Pt dark electrode with an inverse opal Pt electrode fabricated via atomic layer deposition, the dark electrode surface area is boosted by ca. 50-fold. The resulting increase in interfacial electron transfer rate (decrease in charge-transfer resistance) nearly doubles the fill factor and therefore the overall energy conversion efficiency, illustrating the utility of this high-area electrode for DSCs.

Adsorption of cadmium by activated carbon cloth: influence of surface oxidation and solution pH.

PubMed

Rangel-Mendez, J R; Streat, M

2002-03-01

The surface of activated carbon cloth (ACC), based on polyacrylonitrile fibre as a precursor, was oxidised using nitric acid, ozone and electrochemical oxidation to enhance cadmium ion exchange capacity. Modified adsorbents were physically and chemically characterised by pH titration, direct titration, X-ray photoelectron spectroscopy, elemental analysis, surface area and porosimetry, and scanning electron microscopy. BET surface area decreased after oxidation, however, the total ion exchange capacity increased by a factor of approximately 3.5 compared to the commercial as-received ACC. A very significant increase in cadmium uptake, by a factor of 13, was observed for the electrochemically oxidised ACC. Equilibrium sorption isotherms were determined at pH 4, 5 and 6 and these showed that cadmium uptake increased with increasing pH. There was clear evidence of physical damage to ozone-oxidised fibre, however, acid and electrochemically oxidised samples were completely stable.

Satellite monitoring of sea surface pollution

NASA Technical Reports Server (NTRS)

Fielder, G.; Telfer, D. J. (Principal Investigator)

1979-01-01

The author has identified the following significant results. Image processing techniques developed are well adapted to the exploration and isolation of local areas which exhibit small temperature differences between themselves and their surroundings. In the worst case of imagery of small areal extent of sea surface having no coastal boundary in the area, there is yet no method of distinguishing unambiguously an oil spill from fog, cloud, the effect produced by shallow sediments, or the effects of naturally occuring thermal fronts. In the case of uniform slicks of liquid North Sea oil in still air, laboratory simulation experiments show that, for oil thicknesses in excess of 1 or 2 mm, there is, under equilibrium conditions, little dependence of oil surface temperature on the thickness of the oil layer. The surface temperature of oil is consistently higher than that of water, the difference being about 1 K at low values of relative humidity, but tending to increase as the relative humidity increases.

Evaluation of a moderate resolution, satellite-based impervious surface map using an independent, high-resolution validation data set

USGS Publications Warehouse

Jones, J.W.; Jarnagin, T.

2009-01-01

Given the relatively high cost of mapping impervious surfaces at regional scales, substantial effort is being expended in the development of moderate-resolution, satellite-based methods for estimating impervious surface area (ISA). To rigorously assess the accuracy of these data products high quality, independently derived validation data are needed. High-resolution data were collected across a gradient of development within the Mid-Atlantic region to assess the accuracy of National Land Cover Data (NLCD) Landsat-based ISA estimates. Absolute error (satellite predicted area - "reference area") and relative error [satellite (predicted area - "reference area")/ "reference area"] were calculated for each of 240 sample regions that are each more than 15 Landsat pixels on a side. The ability to compile and examine ancillary data in a geographic information system environment provided for evaluation of both validation and NLCD data and afforded efficient exploration of observed errors. In a minority of cases, errors could be explained by temporal discontinuities between the date of satellite image capture and validation source data in rapidly changing places. In others, errors were created by vegetation cover over impervious surfaces and by other factors that bias the satellite processing algorithms. On average in the Mid-Atlantic region, the NLCD product underestimates ISA by approximately 5%. While the error range varies between 2 and 8%, this underestimation occurs regardless of development intensity. Through such analyses the errors, strengths, and weaknesses of particular satellite products can be explored to suggest appropriate uses for regional, satellite-based data in rapidly developing areas of environmental significance. ?? 2009 ASCE.

Study on glacier changes from multi-source remote sensing data in the mountainous areas of the upper reaches of Shule River Basin

NASA Astrophysics Data System (ADS)

Zhang, S.; Li, H.

2017-12-01

The changes of glacier area, ice surface elevation and ice storage in the upper reaches of the Shule River Basin were investigated by the Landsat TM series SRTM and stereo image pairs of Third Resources Satellite (ZY-3)from 2000 to 2015. There are 510 glaciers with areas large than 0.01 km2 in 2015, and the glacier area is 435 km2 in the upper reach of Shule River basin. 96 glaciers were disappeared from 2000 to 2015, and the total glacier area decreased by 57.6±2.68km2 (11.7 %). After correcting the elevation difference between ZY-3 DEM and SRTM and aspect, we found that the average ice surface elevation of glaciers reduced by 2.58±0.6m from 2000 to 2015 , with average reduction 0.172 ±0.04m a-1, and the ice storage reduced by 1.277±0.311km3. Elevation variation of ice surface in different sub-regions reflects the complexity of glacier change. The ice storage change calculated from the sum of single glacier area-volume relationship is glacier 1.46 times higher than that estimated from ice surface elevation change, indicating that the global ice storage change estimated from glacier area-volume change probably overestimated. The shrinkage of glacier increased glacier runoff, and led the significant increase of river runoff. The accuracy of projecting the potential glacier change, glacier runoff and river runoff is the key issues of delicacy water resource management in Shule River Basin.

[Importance of cleaning and disinfection of critical surfaces in dental health services. Impact of an intervention program].

PubMed

Véliz, Elena; Vergara, Teresa; Pearcy, Mercedes; Dabanch, Jeannette

Introduction Dental care has become a challenge for healthcare associated infection prevention programs, since the environment, within other factors, plays an important role in the transmission chain. Materials and Methods An intervention program was designed for the Dental Unit of Hospital Militar de Santiago, between years 2014 and 2015. The program contemplated 3 stages: diagnostic, intervention and evaluation stage. Objective To improve the safety of critical surfaces involved in dental healthcare. Results During the diagnostic stage, the cleaning and disinfection process was found to be deficient. The most contaminated critical surface was the instrument holder unit, then the clean area and lamp handle. The surfaces that significantly reduced their contamination, after the intervention, were the clean area and the instrument carrier unit. Conclusion Training in the processes of cleaning and disinfecting surfaces and dental equipment is one of the cost-effective strategies in preventing healthcare-associated infections (HCAI), with simple and easy-to-apply methods.

Kernel Density Surface Modelling as a Means to Identify Significant Concentrations of Vulnerable Marine Ecosystem Indicators

PubMed Central

Kenchington, Ellen; Murillo, Francisco Javier; Lirette, Camille; Sacau, Mar; Koen-Alonso, Mariano; Kenny, Andrew; Ollerhead, Neil; Wareham, Vonda; Beazley, Lindsay

2014-01-01

The United Nations General Assembly Resolution 61/105, concerning sustainable fisheries in the marine ecosystem, calls for the protection of vulnerable marine ecosystems (VME) from destructive fishing practices. Subsequently, the Food and Agriculture Organization (FAO) produced guidelines for identification of VME indicator species/taxa to assist in the implementation of the resolution, but recommended the development of case-specific operational definitions for their application. We applied kernel density estimation (KDE) to research vessel trawl survey data from inside the fishing footprint of the Northwest Atlantic Fisheries Organization (NAFO) Regulatory Area in the high seas of the northwest Atlantic to create biomass density surfaces for four VME indicator taxa: large-sized sponges, sea pens, small and large gorgonian corals. These VME indicator taxa were identified previously by NAFO using the fragility, life history characteristics and structural complexity criteria presented by FAO, along with an evaluation of their recovery trajectories. KDE, a non-parametric neighbour-based smoothing function, has been used previously in ecology to identify hotspots, that is, areas of relatively high biomass/abundance. We present a novel approach of examining relative changes in area under polygons created from encircling successive biomass categories on the KDE surface to identify “significant concentrations” of biomass, which we equate to VMEs. This allows identification of the VMEs from the broader distribution of the species in the study area. We provide independent assessments of the VMEs so identified using underwater images, benthic sampling with other gear types (dredges, cores), and/or published species distribution models of probability of occurrence, as available. For each VME indicator taxon we provide a brief review of their ecological function which will be important in future assessments of significant adverse impact on these habitats here and elsewhere. PMID:25289667

Kernel density surface modelling as a means to identify significant concentrations of vulnerable marine ecosystem indicators.

PubMed

Kenchington, Ellen; Murillo, Francisco Javier; Lirette, Camille; Sacau, Mar; Koen-Alonso, Mariano; Kenny, Andrew; Ollerhead, Neil; Wareham, Vonda; Beazley, Lindsay

2014-01-01

The United Nations General Assembly Resolution 61/105, concerning sustainable fisheries in the marine ecosystem, calls for the protection of vulnerable marine ecosystems (VME) from destructive fishing practices. Subsequently, the Food and Agriculture Organization (FAO) produced guidelines for identification of VME indicator species/taxa to assist in the implementation of the resolution, but recommended the development of case-specific operational definitions for their application. We applied kernel density estimation (KDE) to research vessel trawl survey data from inside the fishing footprint of the Northwest Atlantic Fisheries Organization (NAFO) Regulatory Area in the high seas of the northwest Atlantic to create biomass density surfaces for four VME indicator taxa: large-sized sponges, sea pens, small and large gorgonian corals. These VME indicator taxa were identified previously by NAFO using the fragility, life history characteristics and structural complexity criteria presented by FAO, along with an evaluation of their recovery trajectories. KDE, a non-parametric neighbour-based smoothing function, has been used previously in ecology to identify hotspots, that is, areas of relatively high biomass/abundance. We present a novel approach of examining relative changes in area under polygons created from encircling successive biomass categories on the KDE surface to identify "significant concentrations" of biomass, which we equate to VMEs. This allows identification of the VMEs from the broader distribution of the species in the study area. We provide independent assessments of the VMEs so identified using underwater images, benthic sampling with other gear types (dredges, cores), and/or published species distribution models of probability of occurrence, as available. For each VME indicator taxon we provide a brief review of their ecological function which will be important in future assessments of significant adverse impact on these habitats here and elsewhere.

Climatology of Urban-regional Systems

NASA Technical Reports Server (NTRS)

Pease, R. W.

1971-01-01

Urbanized areas have come to be significant if not dominant components of many regional land surfaces. They represent perhaps the most dramatic recent change man has made in his environment - a change that may well burgeon in the foreseeable future as greater percentages of world populations crowd into metropolitan areas. The climate of urban-regional systems is involved because temperature, air, and pollutants added to the air are significant aspects of this change. During the past two years, substantial progress has been made in the application of remote sensing techniques to the study of urban climatology by programs jointly sponsored by NASA and the United States Geological Survey. The initial effort has endeavored with considerable success to map terrestrial radiation emission or the general thermal state of the land surface with the aid of imaging radiometers (mechanical-optical scanners).

UV 380 nm Reflectivity of the Earth's Surface

NASA Technical Reports Server (NTRS)

Herman, J. R.; Celarier, E.; Larko, D.

2000-01-01

The 380 nm radiance measurements of TOMS (Total Ozone Mapping Spectrometer) have been converted into a global data set of daily (1979 to 1992) Lambert equivalent reflectivities R of the Earth's surface and boundary layer (clouds, aerosols, surface haze, and snow/ice). Since UV surface reflectivity is between 2 and 8% for both land and water during all seasons of the year (except for ice and snow cover), reflectivities larger than the surface value indicates the presence of clouds, haze, or aerosols in the satellite field of view. Statistical analysis of 14 years of daily data show that most snow/ice-free regions of the Earth have their largest fraction of days each year when the reflectivity is low (R less than 10%). The 380 nm reflectivity data shows that the true surface reflectivity is 2 to 3% lower than the most frequently occurring reflectivity value for each TOMS scene. The most likely cause of this could be a combination of frequently occurring boundary-layer water or aerosol haze. For most regions, the observation of extremely clear conditions needed to estimate the surface reflectivity from space is a comparatively rare occurrence. Certain areas (e.g., Australia, southern Africa, portions of northern Africa) are cloud-free more than 80% of the year, which exposes these regions to larger amounts of UV radiation than at comparable latitudes in the Northern Hemisphere. Regions over rain-forests, jungle areas, Europe and Russia, the bands surrounding the Arctic and Antarctic regions, and many ocean areas have significant cloud cover (R greater than 15%) more than half of each year. In the low to middle latitudes, the areas with the heaviest cloud cover (highest reflectivity for most of the year) are the forest areas of northern South America, southern Central America, the jungle areas of equatorial Africa, and high mountain regions such as the Himalayas or the Andes. The TOMS reflectivity data show the presence of large nearly clear ocean areas and the effects of the major ocean currents on cloud production.

UV 380 nm reflectivity of the Earth's surface, clouds and aerosols

NASA Astrophysics Data System (ADS)

Herman, J. R.; Celarier, E.; Larko, D.

2001-03-01

The 380 nm radiance measurements of the Total Ozone Mapping Spectrometer (TOMS) have been converted into a global data set of daily (1979-1992) Lambert equivalent reflectivities R of the Earth's surface and boundary layer (clouds, aerosols, surface haze, and snow/ice) and then corrected to RPC for the presence of partly clouded scenes. Since UV surface reflectivity is between 2 and 8% for both land and water during all seasons of the year (except for ice and snow cover), reflectivities larger than the surface value indicate the presence of clouds, haze, or aerosols in the satellite field of view. A statistical analysis of 14 years of daily reflectivity data shows that most snow-/ice-free scenes observed by TOMS have a reflectivity less than 10% for the majority of days during a year. The 380 nm reflectivity data show that the true surface reflectivity is 2-3% lower than the most frequently occurring reflectivity value for each TOMS scene as seen from space. Most likely the cause is a combination of frequently occurring boundary layer water and/or aerosol haze. For most regions the observation of extremely clear conditions needed to estimate the surface reflectivity from space is a comparatively rare occurrence. Certain areas (e.g., Australia, southern Africa, portions of northern Africa) are cloud-free more than 80% of the year, which exposes these regions to larger amounts of UV radiation than at comparable latitudes in the Northern Hemisphere. Regions over rain forests, jungle areas, Europe and Russia, the bands surrounding the Arctic and Antarctic regions, and many ocean areas have significant cloud cover (R>15%) more than half of each year. In the low to middle latitudes the areas with the heaviest cloud cover (highest reflectivity for most of the year) are the forest areas of northern South America, southern Central America, the jungle areas of equatorial Africa, and high mountain regions such as the Himalayas or the Andes. The TOMS reflectivity data show both the presence of large nearly clear ocean areas and the effects of the major ocean currents on cloud production.

Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro-Computed Tomographic Study.

PubMed

de Almeida, Bernardo Corrêa; Ormiga, Fabíola; de Araújo, Marcos César Pimenta; Lopes, Ricardo Tadeu; Lima, Inayá Corrêa Barbosa; dos Santos, Bernardo Camargo; Gusman, Heloisa

2015-12-01

The aim of this study was to make a 3-dimensional comparison of the canal transportation and changes in apical geometry using micro-computed tomographic imaging after canal preparation with K3 (SybronEndo, Orange, CA) and K3XF (SybronEndo) file systems. Twenty-eight mandibular molars were randomly divided into 2 groups according to the rotary system used in instrumentation: K3 or K3XF. The specimens were scanned by micro-computed tomographic imaging before and after instrumentation. Images before and after instrumentation from each group were compared with regard to canal volume, surface area, and structure model index (SMI) (paired t test, P < .05). After instrumentation, the canals from each group were compared regarding the changes in volume, surface area, SMI, and canal transportation in the last 4 apical mm (t test, P < .05). Instrumentation with the 2 rotary systems significantly changed the canal volume, surface area, and SMI (P < .05). There were no significant differences between instrument types concerning these parameters (P > .05). There were no significant differences between the 2 groups with regard to canal transportation in the last 4 apical mm (P > .05). Both rotary systems showed adequate canal preparations with reduced values of canal transportation. Heat treatment did not influence changes in root canal geometry in the apical region. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The digestive adaptation of flying vertebrates: high intestinal paracellular absorption compensates for smaller guts.

PubMed

Caviedes-Vidal, Enrique; McWhorter, Todd J; Lavin, Shana R; Chediack, Juan G; Tracy, Christopher R; Karasov, William H

2007-11-27

Anecdotal evidence suggests that birds have smaller intestines than mammals. In the present analysis, we show that small birds and bats have significantly shorter small intestines and less small intestine nominal (smooth bore tube) surface area than similarly sized nonflying mammals. The corresponding >50% reduction in intestinal volume and hence mass of digesta carried is advantageous because the energetic costs of flight increase with load carried. But, a central dilemma is how birds and bats satisfy relatively high energy needs with less absorptive surface area. Here, we further show that an enhanced paracellular pathway for intestinal absorption of water-soluble nutrients such as glucose and amino acids may compensate for reduced small intestines in volant vertebrates. The evidence is that l-rhamnose and other similarly sized, metabolically inert, nonactively transported monosaccharides are absorbed significantly more in small birds and bats than in nonflying mammals. To broaden our comparison and test the veracity of our finding we surveyed the literature for other similar studies of paracellular absorption. The patterns found in our focal species held up when we included other species surveyed in our analysis. Significantly greater amplification of digestive surface area by villi in small birds, also uncovered by our analysis, may provide one mechanistic explanation for the observation of higher paracellular absorption relative to nonflying mammals. It appears that reduced intestinal size and relatively enhanced intestinal paracellular absorption can be added to the suite of adaptations that have evolved in actively flying vertebrates.

The healing effects of a topical phytogenic ointment on insect bite hypersensitivity lesions in horses.

PubMed

van den Boom, R; Kempenaars, M; van Oldruitenborgh-Oosterbaan, M M Sloet

2011-01-01

Insect bite hypersensitivity (IBH) is the most common cause of pruritus in horses and is a serious welfare issue for affected animals. In this study, the effect of a topical phytogenic ointment on the healing of cutaneous lesions was investigated in a double-blind trial involving 26 horses with I B H. The number of lesions and their total surface area were recorded on days 0, 7, and 21 in horses treated for 3 weeks with either verum or placebo ointment. After unblinding of treatment assignment, the horses that had been treated with the placebo ointment received the verum preparation for an additional 3 weeks and the number of lesions and their total surface area were again recorded. This part of the study was not blinded. The number of lesions and the total surface area decreased in both treatment groups (no significant difference). Owners also scored the degree of discomfort suffered by their horses as a result of IBH lesions, and at the end of the 3-week period this score was significantly lower in the verum than in the placebo group (P = 0.04). When placebo-treated horses subsequently received the verum ointment, their wound severity score also decreased significantly (P < 0.01). Daily application of an ointment (verum or placebo) does not cure IBH, but use of the phytogenic ointment led to a decrease in the owner-assessed discomfort suffered by horses.

Oxidation of platinum nickel nanowires to improve durability of oxygen-reducing electrocatalysts

DOE PAGES

Alia, Shaun M.; Pylypenko, Svitlana; Dameron, Arrelaine; ...

2016-01-12

In this study, the impact of heat treating platinum-coated nickel (Pt-Ni) nanowires in oxygen is examined to determine the effect on oxygen reduction (ORR) activity and durability. Pt-Ni nanowires exhibit promising ORR mass activities (3 times greater than Pt nanoparticles, 1.5 times greater than U.S. Department of Energy target) both before and after potential cycling for all but the highest annealing temperatures explored. The annealing of Pt-Ni nanowires in oxygen with increasing temperature is found to reduce surface area and ORR activity in comparison to the untreated material, but also reduces activity losses following durability testing. Following potential cycling, unannealedmore » Pt-Ni nanowires show significant losses in surface area (23%) and specific activity (18%) while Pt-Ni nanowires annealed at 200°C show modest increases in surface area (2%) and specific activity (6%) after potential cycling. Increasing annealing temperatures also show a clear trend of decreasing Ni dissolution rates. While oxygen annealing has shown the ability to improve durability of Pt-Ni nanowires, significant Ni dissolution was observed in all samples and suggests oxide passivation while showing promise for improved durability, when employed by itself is insufficient to prevent all contamination concerns involving Ni dissolution.« less

Mapping cortical brain asymmetry in 17,141 healthy individuals worldwide via the ENIGMA Consortium.

PubMed

Kong, Xiang-Zhen; Mathias, Samuel R; Guadalupe, Tulio; Glahn, David C; Franke, Barbara; Crivello, Fabrice; Tzourio-Mazoyer, Nathalie; Fisher, Simon E; Thompson, Paul M; Francks, Clyde

2018-05-29

Hemispheric asymmetry is a cardinal feature of human brain organization. Altered brain asymmetry has also been linked to some cognitive and neuropsychiatric disorders. Here, the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium presents the largest-ever analysis of cerebral cortical asymmetry and its variability across individuals. Cortical thickness and surface area were assessed in MRI scans of 17,141 healthy individuals from 99 datasets worldwide. Results revealed widespread asymmetries at both hemispheric and regional levels, with a generally thicker cortex but smaller surface area in the left hemisphere relative to the right. Regionally, asymmetries of cortical thickness and/or surface area were found in the inferior frontal gyrus, transverse temporal gyrus, parahippocampal gyrus, and entorhinal cortex. These regions are involved in lateralized functions, including language and visuospatial processing. In addition to population-level asymmetries, variability in brain asymmetry was related to sex, age, and intracranial volume. Interestingly, we did not find significant associations between asymmetries and handedness. Finally, with two independent pedigree datasets ( n = 1,443 and 1,113, respectively), we found several asymmetries showing significant, replicable heritability. The structural asymmetries identified and their variabilities and heritability provide a reference resource for future studies on the genetic basis of brain asymmetry and altered laterality in cognitive, neurological, and psychiatric disorders.

Residual contamination and corrosion on electrochemically marked uranium

NASA Astrophysics Data System (ADS)

Seals, R. D.; Bullock, J. S.; Cristy, S. S.; Bennett, R. K.

Residual contamination and potential corrosion problems on uranium parts electrochemically marked with PHB-1 and PHB-1E electroetchants have been investigated using ion microprobe mass analysis (IMMA), scanning electron microscopy (SEM), and light microscopy (LM). The effectiveness of various solvent-cleaning sequences and the influence of the use of an abrasive cleaner were evaluated. The corrosion depths and chlorine distributions resulting from the electroetching process were determined. To meet the objective, the surfaces of uranium coupons, which had been processed according to production procedures for parts, i.e., machining, cleaning, marking, inspecting and coating with Shell Vitrea-29® oil, were studied. The greater surface wetting capability of the PHB-1E electroetchant solution relative to PHB-1 resulted in less localized corrosion at the point of attack which provided a more legible mark. Components of the electroetchants (aluminum, potassium and chromium) were found in the marked areas of both types of electroetched samples. Chromium, resulting from the corrosion inhibitor in the electroetchants, was found in the etched areas as well as on the coupon away from the electroetched areas. Depth profile data indicated that the major etching action (marking thickness) of the electroetchants penetrated to a depth of approximately 200 nm. Trace amounts of chlorine were present primarily within the first 65 nm of the marked surface. Comparison of the solvent rinsing sequences revealed that the most effective cleaning process included a degreaser, such as perchloroethylene, followed by a polar solvent, such as alcohol. Evaluation of the use of an abrasive cleaner on the electroetched areas indicates that this process removed residual contaminants, increased mark legibility and did not introduce significant residuals from the abrading material or cause significant surface damage.

Effect of deformation on the thermal conductivity of granular porous media with rough grain surface

NASA Astrophysics Data System (ADS)

Askari, Roohollah; Hejazi, S. Hossein; Sahimi, Muhammad

2017-08-01

Heat transfer in granular porous media is an important phenomenon that is relevant to a wide variety of problems, including geothermal reservoirs and enhanced oil recovery by thermal methods. Resistance to flow of heat in the contact area between the grains strongly influences the effective thermal conductivity of such porous media. Extensive experiments have indicated that the roughness of the grains' surface follows self-affine fractal stochastic functions, and thus, the contact resistance cannot be accounted for by models based on smooth surfaces. Despite the significance of rough contact area, the resistance has been accounted for by a fitting parameter in the models of heat transfer. In this Letter we report on a study of conduction in a packing of particles that contains a fluid of a given conductivity, with each grain having a rough self-affine surface, and is under an external compressive pressure. The deformation of the contact area depends on the fractal dimension that characterizes the grains' rough surface, as well as their Young's modulus. Excellent qualitative agreement is obtained with experimental data. Deformation of granular porous media with grains that have rough self-affine fractal surface is simulated. Thermal contact resistance between grains with rough surfaces is incorporated into the numerical simulation of heat conduction under compressive pressure. By increasing compressive pressure, thermal conductivity is enhanced more in the grains with smoother surfaces and lower Young's modulus. Excellent qualitative agreement is obtained with the experimental data.

Estimating the surface area of birds: using the homing pigeon (Columba livia) as a model.

PubMed

Perez, Cristina R; Moye, John K; Pritsos, Chris A

2014-05-08

Estimation of the surface area of the avian body is valuable for thermoregulation and metabolism studies as well as for assessing exposure to oil and other surface-active organic pollutants from a spill. The use of frozen carcasses for surface area estimations prevents the ability to modify the posture of the bird. The surface area of six live homing pigeons in the fully extended flight position was estimated using a noninvasive method. An equation was derived to estimate the total surface area of a pigeon based on its body weight. A pigeon's surface area in the fully extended flight position is approximately 4 times larger than the surface area of a pigeon in the perching position. The surface area of a bird is dependent on its physical position, and, therefore, the fully extended flight position exhibits the maximum area of a bird and should be considered the true surface area of a bird. © 2014. Published by The Company of Biologists Ltd | Biology Open.

Evaluating DEM conditioning techniques, elevation source data, and grid resolution for field-scale hydrological parameter extraction

NASA Astrophysics Data System (ADS)

Woodrow, Kathryn; Lindsay, John B.; Berg, Aaron A.

2016-09-01

Although digital elevation models (DEMs) prove useful for a number of hydrological applications, they are often the end result of numerous processing steps that each contains uncertainty. These uncertainties have the potential to greatly influence DEM quality and to further propagate to DEM-derived attributes including derived surface and near-surface drainage patterns. This research examines the impacts of DEM grid resolution, elevation source data, and conditioning techniques on the spatial and statistical distribution of field-scale hydrological attributes for a 12,000 ha watershed of an agricultural area within southwestern Ontario, Canada. Three conditioning techniques, including depression filling (DF), depression breaching (DB), and stream burning (SB), were examined. The catchments draining to each boundary of 7933 agricultural fields were delineated using the surface drainage patterns modeled from LiDAR data, interpolated to a 1 m, 5 m, and 10 m resolution DEMs, and from a 10 m resolution photogrammetric DEM. The results showed that variation in DEM grid resolution resulted in significant differences in the spatial and statistical distributions of contributing areas and the distributions of downslope flowpath length. Degrading the grid resolution of the LiDAR data from 1 m to 10 m resulted in a disagreement in mapped contributing areas of between 29.4% and 37.3% of the study area, depending on the DEM conditioning technique. The disagreements among the field-scale contributing areas mapped from the 10 m LiDAR DEM and photogrammetric DEM were large, with nearly half of the study area draining to alternate field boundaries. Differences in derived contributing areas and flowpaths among various conditioning techniques increased substantially at finer grid resolutions, with the largest disagreement among mapped contributing areas occurring between the 1 m resolution DB DEM and the SB DEM (37% disagreement) and the DB-DF comparison (36.5% disagreement in mapped areas). These results demonstrate that the decision to use one DEM conditioning technique over another, and the constraints of available DEM data resolution and source, can greatly impact the modeled surface drainage patterns at the scale of individual fields. This work has significance for applications that attempt to optimize best-management practices (BMPs) for reducing soil erosion and runoff contamination within agricultural watersheds.

Modeling of microclimatic characteristics of highland area

NASA Astrophysics Data System (ADS)

Sitdikova, Iuliia; Rusin, Igor

2013-04-01

Microclimatic characteristics of highlands may vary considerably over distances of a few meters depending on slope and aspect. There is a problem of estimation of components of surface energy balance based on observation of single stations for description of microclimate highlands. The aim of this paper is to develop a method that would restore microclimatic characteristics of terrain, based on observations of the single station, by physical extrapolation. The input parameters to obtain the microclimatic characteristics are as follows: air temperature, relative humidity, and wind speed on two vertical levels, air pressure, surface temperature, direct and diffused solar radiation and surface albedo. The recent version of the Meteorological Radiation Model (MRM) has been used to calculate a solar radiation over the area and to estimate an influence of cloudiness amounts. The height, slope and aspect were accounted at each point with using a digital elevation model. Have been supposed that air temperature and specific humidity vary with altitude only. Net radiation was calculated at all points of the area. Supposed that the difference between the surface temperature and the air temperature is a linear function of net radiation. The empirical coefficient, which depends on wind speed with adjustment of given area. Latent and sensible fluxes are calculated by using the modified Bowen ratio, which varies on the area. Method was tested on field research in Krasnodar region (RF). The meteorological observations were made every three hour on actinometric and gradient sites. The editional gradient site with different orientation of the slope was organized from 400 meters of the main site. Topographic survey of area was made 1x1,3 km in size for a digital elevation model constructing. At all points of the area of radiation and heat balance were calculated. The results of researches are the maps of surface temperature, net radiation, latent and sensible fluxes. The calculations showed that the average value of components of heat balance by area differ significantly from the data observed on meteorological station.

Trend-surface analysis of morphometric parameters: A case study in southeastern Brazil

NASA Astrophysics Data System (ADS)

Grohmann, Carlos Henrique

2005-10-01

Trend-surface analysis was carried out on data from morphometric parameters isobase and hydraulic gradient. The study area, located in the eastern border of Quadrilátero Ferrífero, southeastern Brazil, presents four main geomorphological units, one characterized by fluvial dissection, two of mountainous relief, with a scarp of hundreds of meters of fall between them, and a flat plateau in the central portion of the fluvially dissected terrains. Morphometric maps were evaluated in GRASS-GIS and statistics were made on R statistical language, using the spatial package. Analysis of variance (ANOVA) was made to test the significance of each surface and the significance of increasing polynomial degree. The best results were achieved with sixth-order surface for isobase and second-order surface for hydraulic gradient. Shape and orientation of residual maps contours for selected trends were compared with structures inferred from several morphometric maps, and a good correlation is present.

[Spatial variability of surface soil nutrients in the landslide area of Beichuan County, South- west China, after 5 · 12 Wenchuan Earthquake].

PubMed

Mai, Ji-shan; Zhao, Ting-ning; Zheng, Jiang-kun; Shi, Chang-qing

2015-12-01

Based on grid sampling and laboratory analysis, spatial variability of surface soil nutrients was analyzed with GS⁺ and other statistics methods on the landslide area of Fenghuang Mountain, Leigu Town, Beichuan County. The results showed that except for high variability of available phosphorus, other soil nutrients exhibited moderate variability. The ratios of nugget to sill of the soil available phosphorus and soil organic carbon were 27.9% and 28.8%, respectively, showing moderate spatial correlation, while the ratios of nugget to sill of the total nitrogen (20.0%), total phosphorus (24.3%), total potassium (11.1%), available nitrogen (11.2%), and available potassium (22.7%) suggested strong spatial correlation. The total phosphorus had the maximum range (1232.7 m), followed by available nitrogen (541.27 m), total nitrogen (468.35 m), total potassium (136.0 m), available potassium (128.7 m), available phosphorus (116.6 m), and soil organic carbon (93.5 m). Soil nutrients had no significant variation with the increase of altitude, but gradually increased from the landslide area, the transition area, to the little-impacted area. The total and available phosphorus contents of the landslide area decreased by 10.3% and 79.7% compared to that of the little-impacted area, respectively. The soil nutrient contents in the transition area accounted for 31.1%-87.2% of that of the little-impacted area, with the nant reason for the spatial variability of surface soil nutrients.

Assessment and application of a snowblow modelling approach for identifying enhanced snow accumulation in areas of former glaciation

NASA Astrophysics Data System (ADS)

Mills, Stephanie; Smith, Michael; Le Brocq, Anne; Ardakova, Ekaterina; Hillier, John; Boston, Clare

2016-04-01

The redistribution of snow by wind can play an important role in providing additional mass to the surface of glaciers and can, therefore, have an impact on the glacier's surface mass balance. In areas of marginal glaciation, this local topo-climatic effect may be prove crucial for the initiation and survival of glaciers, whilst it can also increase heterogeneity in the distribution of snow on ice caps and ice sheets. We present a newly developed snowblow model which calculates spatial variations in relative snow accumulation that result from variations in topography. We apply this model to areas of former marginal glaciation in the Brecon Beacons, Wales and an area of former plateau icefield glaciation in the Monadhliath, Scotland. We can then determine whether redistribution by snow can help explain variations in the estimated equilibrium line altitudes (ELAs) of these former glaciers. Specifically, we compare the areas where snow is modelled as accumulating, to the reconstructed glacier surface, which is based on mapped moraines believed to be of Younger Dryas age. The model is applied to 30 m resolution DEMs and potential snow accumulation is simulated from different wind directions in order to determine the most likely contributing sector. Total snow accumulation in sub-set areas is then calculated and compared to the reconstructed glacier area. The results suggest that areas with larger amounts of snow accumulation often correspond with those where the ELA is lower than surrounding glaciers and vice versa, in both the marginal and icefield setting, suggesting that the role of snowblow in supplying additional mass to the surface of glaciers is significant.

Map showing mineral resource potential of the Paiute Instant (Primitive) Study Area, Mohave County, Arizona

USGS Publications Warehouse

Villalobos, Hector A.; Hamm, Louis W.

1981-01-01

Several areas in the Paiute Instant Study Area are judged to have at best a low mineral potential. These include areas of copper, lead, manganese, molybdenum, nickel, silver, tungsten, and zinc mineralization, as well as occurrences of dumortierite, beryllium, arsenic, barium, gypsum, gem minerals, sand, gravel, and limestone. The metallic deposits and dumortieri te, beryllium, and arsenic occur over small surface areas. Significant production has not resulted from mining activity in mineralized areas. Sand, gravel, limestone, gem minerals, gypsum, and barium occurrences are far from major markets. Currently, there are no active mining operations in the study area.

The Indo-Pacific Warm Pool: critical to world oceanography and world climate

NASA Astrophysics Data System (ADS)

De Deckker, Patrick

2016-12-01

The Indo-Pacific Warm Pool holds a unique place on the globe. It is a large area [>30 × 106 km2] that is characterised by permanent surface temperature >28 °C and is therefore called the `heat engine' of the globe. High convective clouds which can reach altitudes up to 15 km generate much latent heat in the process of convection and this area is therefore called the `steam engine' of the world. Seasonal and contrasting monsoonal activity over the region is the cause for a broad seasonal change of surface salinities, and since the area lies along the path of the Great Ocean Conveyor Belt, it is coined the `dilution' basin due to the high incidence of tropical rain and, away from the equator, tropical cyclones contribute to a significant drop in sea water salinity. Discussion about what may happen in the future of the Warm Pool under global warming is presented together with a description of the Warm Pool during the past, such as the Last Glacial Maximum when sea levels had dropped by ~125 m. A call for urgent monitoring of the IPWP area is justified on the grounds of the significance of this area for global oceanographic and climatological processes, but also because of the concerned threats to human population living there.

Soil hydrological and soil property changes resulting from termite activity on agricultural fields in Burkina Faso

NASA Astrophysics Data System (ADS)

Mettrop, I.; Cammeraat, L. H.; Verbeeten, E.

2009-04-01

Termites are important ecosystem-engineers in subtropical and tropical regions. The effect of termite activity affecting soil infiltration is well documented in the Sahelian region. Most studies find increased infiltration rates on surfaces that are affected by termite activity in comparison to crusted areas showing non-termite presence. Crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity were compared to control fields without visual ground dwelling termite activity. Fine scale rainfall simulations were carried out on crusted termite affected and control sites. Furthermore soil moisture change, bulk density, soil organic matter as well as general soil characteristics were studied. The top soils in the study area were strongly crusted (structural crust) after the summer rainfall and harvest of millet. They have a loamy sand texture underlain by a shallow sandy loam Bt horizon. The initial soil moisture conditions were significantly higher on the termite plots when compared to control sites. It was found that the amount of runoff produced on the termite plots was significantly higher, and also the volumetric soil moisture content after the experiments was significantly lower if compared to the control plots. Bulk density showed no difference whereas soil organic matter was significantly higher under termite affected areas, in comparison to the control plots. Lab tests showed no significant difference in hydrophobic behavior of the topsoil and crust material. Micro and macro-structural properties of the topsoil did not differ significantly between the termite sites and the control sites. The texture of the top 5 cm of the soil was also found to be not significantly different. The infiltration results are contradictory to the general literature, which reports increased infiltration rates after prolonged termite activity although mostly under different initial conditions. The number of nest entrances was clearly higher in the termite areas, but apparently did not significantly affect infiltration. The increased soil organic matter contents in the termite affected areas however, are as expected from literature, but did not improve soil aggregation which would be expected given the importance of organic matter in soil aggregation in this type of soils. One of the explanations for the reduced infiltration rates might be that termites bring clay from the finer textured subsoil to the surface to build casts over the organic material on the surface (mainly millet stems). It is speculated that the excavated clay material could be involved in crust formation, only present is in the upper 0.5 cm of the soil crust, which is enough to block pores in the crust surface, hampering infiltration. The topsoil aggregates are slaking under the summer rainfall and the increase in fine textured material, excavated by the termites, could be incorporated into the crust and reduce infiltration. Furthermore this specific effect might also be related to the type of termite involved, as impacts from ecosystem engineers on their environment is highly dependent on the specific species involved.

Use of the Nitrogen Index to assess nitrate leaching and water drainage from plastic-mulched horticultural cropping systems of Florida

USDA-ARS?s Scientific Manuscript database

Water quality in Florida is significantly impacted by nitrogen (N) losses from agriculture in a large part of the state, where there is a close interaction between surface water and groundwater that has a high water table. Horticultural crops are planted across large areas of Florida, including area...

Silicon on ceramic process. Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Zook, J. D.; Heaps, J. D.; Maciolek, R. B.; Koepke, B. G.; Butter, C. D.; Schuldt, S. B.

1977-01-01

The technical and economic feasibility of producing solar-cell-quality sheet silicon was investigated. The sheets were made by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress was made in all areas of the program.

Environmental arsenic exposure of schoolchildren in a former tin mining and smelting community of southern Thailand.

PubMed

Vitayavirasak, Banjong; Rakwong, Kittiya; Chatchawej, Warangkana

2005-01-01

Risk behavior and environmental sources of exposure to arsenic for 10-year-old schoolchildren were studied in a high exposure area and a low exposure area of Ron Phibun Subdistrict, Ron Phibun District, Nakhon Si Thammarat Province and compared to those in a control area. Arsenic concentrations of surface soil, ambient air and drinking water to which subjects in the high exposure group, the low exposure group and the control group were exposed, were significantly different (p < 0.05). Similarly, urinary concentrations of total arsenic and the sum of inorganic arsenic and its metabolites were significantly higher in the study groups than the control group. The arsenic content of locally grown agricultural produce was small with the exception of freshwater snails (Sinotaia ingallsiana). Drinking water and surface soil were found to be the main sources of exposure. The exposure was mediated by the subjects' risk behavior, such as playing with soil and no hand-washing before eating. The estimated cancer risk from arsenic for the schoolchildren in the study area was between 10(-5)-10(-6) which meant that their risk of developing cancer was probable. Measures to reduce the cancer risk are recommended.

Isotopic ratios of 36Cl/Cl in Japanese surface soil

NASA Astrophysics Data System (ADS)

Seki, R.; Matsuhiro, T.; Nagashima, Y.; Takahashi, T.; Sasa, K.; Sueki, K.; Tosaki, Y.; Bessho, K.; Matsumura, H.; Miura, T.

2007-06-01

We have measured the 36Cl/Cl ratio of uncultivated surface soil samples collected from 11 areas distributed throughout Japan to determine the undisturbed value of the ratio. The ratio was found to be on the order of 10-13 except for the Tokai-mura area, where four research reactors, two commercial nuclear power plants and a nuclear fuel reprocessing plant have been operated. The observed ratio in the Tokai-mura area was higher than 10-12. Notably, soil samples collected from a site of commercial BWR nuclear power plants in Fukushima prefecture showed no significant increase in 36Cl/Cl ratio. The 36Cl/Cl ratio depth profiles of soil samples collected at both of Makabe-town and Tokai-mura were also measured. Since Makabe-town is located about 50 km apart from Tokai-mura, we do not expect it to be affected by the nuclear facilities. No large variations were observed in the Makabe depth profile; the measured ratios ranged from ∼3 to ∼5 × 10-13. The result obtained for Tokai-mura is significantly different in that from the surface to about 80 cm depth, the measured ratios, ∼10-12, are much higher than any at Makabe. At depth below 80 cm, the Tokai-mura ratios are lower and become indistinguishable from those at Makabe. The 36Cl/Cl ratio in unaffected areas of Japan is estimated to be 3-4 × 10-13.

Rates of Water Loss and Uptake in Recalcitrant Fruits of Quercus Species Are Determined by Pericarp Anatomy

PubMed Central

Xia, Ke; Daws, Matthew I.; Stuppy, Wolfgang; Zhou, Zhe-Kun; Pritchard, Hugh W.

2012-01-01

Desiccation-sensitive recalcitrant seeds and fruits are killed by the loss of even moderate quantities of water. Consequently, minimizing the rate of water loss may be an important ecological factor and evolutionary driver by reducing the risk of mortality during post-dispersal dry-spells. For recalcitrant fruits of a range of Quercus species, prolonged drying times have been observed previously. However, the underlying mechanism(s) for this variation is unknown. Using nine Quercus species we investigated the major route(s) of water flow into and out of the fruits and analysed the relative importance of the different pericarp components and their anatomy on water uptake/loss. During imbibition (rehydration), the surface area of the cupule scar and the frequency and area of the vascular bundles contained therein were significantly correlated with the rates of water uptake across the scar. The vascular bundles serving the apex of the fruit were a minor contributor to overall water. Further, the rate of water uptake across the remainder of the pericarp surface was significantly correlated with the thickness of the vascularised inner layer in the pericarp. Fruits of Q. franchetii and Q. schottkyana dried most slowly and had a comparatively small scar surface area with few vascular bundles per unit area. These species inhabit drier regions than the other species studied, suggesting these anatomical features may have ecological value by reducing the risk of desiccation stress. However, this remains to be tested in the field. PMID:23071795

Treatment of vitiligo with the topical Janus kinase inhibitor ruxolitinib.

PubMed

Rothstein, Brooke; Joshipura, Deep; Saraiya, Ami; Abdat, Rana; Ashkar, Huda; Turkowski, Yana; Sheth, Vaneeta; Huang, Victor; Au, Shiu Chung; Kachuk, Courtney; Dumont, Nicole; Gottlieb, Alice B; Rosmarin, David

2017-06-01

Existing therapies for vitiligo are limited in efficacy and can be associated with undesirable side effects. Topical Janus kinase inhibitors may offer a new therapeutic option for vitiligo. We sought to assess the role of topical ruxolitinib 1.5% cream, a Janus kinase inhibitor, in vitiligo treatment. This 20-week, open-label, proof-of-concept trial of twice-daily topical ruxolitinib 1.5% cream was conducted in 12 patients with a minimum of 1% affected body surface area of vitiligo. The primary outcome was percent improvement in Vitiligo Area Scoring Index from baseline to week 20. Of 12 patients screened, 11 were enrolled and 9 completed the study (54.5% men; mean age, 52 years). Four patients with significant facial involvement at baseline had a 76% improvement in facial Vitiligo Area Scoring Index scores at week 20 (95% confidence interval, 53-99%; P = .001). A 23% improvement in overall Vitiligo Area Scoring Index scores was observed in all enrolled patients at week 20 (95% confidence interval, 4-43%; P = .02). Three of 8 patients responded on body surfaces and 1 of 8 patients responded on acral surfaces. Adverse events were minor, including erythema, hyperpigmentation, and transient acne. Limitations of the study include the small sample size and open-label study design. Topical ruxolitinib 1.5% cream provided significant repigmentation in facial vitiligo and may offer a valuable new treatment for vitiligo. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Rough surface adhesion in the presence of capillary condensation

DOE PAGES

DelRio, Frank W.; Dunn, Martin L.; Phinney, Leslie M.; ...

2007-04-17

Capillary condensation of water can have a significant effect on rough surface adhesion. Here, to explore this phenomenon between micromachined surfaces, the authors perform microcantilever experiments as a function of surface roughness and relative humidity (RH). Below a threshold RH, the adhesion is mainly due to van der Waals forces across extensive noncontacting areas. Above the threshold RH, the adhesion jumps due to capillary condensation and increases towards the upper limit of Γ=144mJ/m 2. Lastly, a detailed model based on the measured surface topography qualitatively agrees with the experimental data only when the topographic correlations between the upper and lowermore » surfaces are considered.« less

Proteins, Platelets, and Blood Coagulation at Biomaterial Interfaces

PubMed Central

Xu, Li-Chong; Bauer, James; Siedlecki, Christopher A.

2015-01-01

Blood coagulation and platelet adhesion remain major impediments to the use of biomaterials in implantable medical devices. There is still significant controversy and question in the field regarding the role that surfaces play in this process. This manuscript addresses this topic area and reports on state of the art in the field. Particular emphasis is placed on the subject of surface engineering and surface measurements that allow for control and observation of surface-mediated biological responses in blood and test solutions. Appropriate use of surface texturing and chemical patterning methodologies allow for reduction of both blood coagulation and platelet adhesion, and new methods of surface interrogation at high resolution allow for measurement of the relevant biological factors. PMID:25448722

Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement.

PubMed

Reza, Fazal; Ibrahim, Nur Sukainah

2015-01-01

Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group.

Effects of tooth whitening and orange juice on surface properties of dental enamel.

PubMed

Ren, Yan-Fang; Amin, Azadeh; Malmstrom, Hans

2009-06-01

To study the effects of 6% H2O2 activated with LED light on surface enamel as compared to orange juice challenges in vitro. A total of 40 human enamel discs were incubated in saliva overnight to allow pellicle formation and then divided into three groups: 15 for whitening treatments, 15 for orange juice immersions and 10 for normal saline controls. Baseline microhardness was measured with a microhardness Knoop indenter (50g, 10s) and surface topography was evaluated with a focus-variation 3D scanning microscopy. Enamel discs were treated with H2O2 or orange juice for 20 min each cycle for five cycles to simulate daily treatment with the products for 5 days. The discs were stored in saliva between treatment cycles. Microhardness and surface topography were evaluated again after treatments. Changes in microhardness and in surface area roughness (Sa), mean maximum peak-to-valley distance (Sz) and the developed surface area ratio (Sdr) were compared before and after treatments (t-test) and among groups (ANOVA). Enamel surface hardness decreased by 84% after orange juice immersion but no statistically significant changes were observed in the whitening and control groups. Surface topography changed significantly only in the orange juice group as shown by increased Sa (1.2 microm vs. 2.0 microm), Sz (7.7 microm vs. 10.2 microm) and Sdr (2.8% vs. 6.0%). No such changes were observed in the whitening and control groups. In comparison to orange juice challenges, the effects of 6% H2O2 on surface enamel are insignificant. Orange juice erosion markedly decreased hardness and increased roughness of enamel.

Effect of ultraviolet light irradiation on bond strength of fiber post: Evaluation of surface characteristic and bonded area of fiber post with resin cement

PubMed Central

Reza, Fazal; Ibrahim, Nur Sukainah

2015-01-01

Objective: Fiber post is cemented to a root canal to restore coronal tooth structure. This research aims to evaluate the effect of ultraviolet (UV) irradiation on bond strength of fiber post with resin cement. Materials and Methods: A total of 40 of the two types of fiber posts, namely, FRC Prostec (FRC) and Fiber KOR (KOR), were used for the experiment. UV irradiation was applied on top of the fiber post surface for 0, 15, 20, and 30 min. The irradiated surface of the fiber posts (n = 5) were immediately bonded with resin cement (Rely X U200) after UV irradiation. Shear bond strength (SBS) MPa was measured, and the dislodged area of post surfaces was examined with scanning electron microscopes. Changes in surface roughness (Ra) of the FRC group after UV irradiation were observed (n = 3) using atomic force microscopy. Data of SBS were statistically analyzed using one-way analysis of variance, followed by multiple comparisons (P < 0.05). Results: SBS was significantly higher for 20 min of UV irradiation of the FRC group while significantly higher SBS was observed with 15 min of UV irradiation of the KOR group. Resin cement was more evident (cohesive failure) on the dislodged post surface of the UV treated groups compared with the control. The surface roughness of the FRC post was Ra = 175.1 nm and Ra = 929.2 nm for the control and the 20 min group, respectively. Conclusions: Higher surface roughness of the UV irradiated group indicated formation of mechanical retention on the fiber post surface. Evidence of cohesive failure was observed which indicated higher SBS of fiber post with the UV irradiated group. PMID:25713488

Preliminary results of fisheries investigation associated with Skylab-3. [remotely sensed distribution and abundance of gamefish in Gulf of Mexico

NASA Technical Reports Server (NTRS)

Savastano, K. J. (Principal Investigator); Pastula, E. J., Jr.; Woods, G.; Faller, K.

1974-01-01

The author has identified the following significant results. This investigation is to establish the feasibility of utilizing remotely sensed data acquired from aircraft and satellite platforms to provide information concerning the distribution and abundance of oceanic gamefish. Data from the test area in the northeastern Gulf of Mexico has made possible the identification of fisheries significant environmental parameters for white marlin. Predictive models based on catch data and surface truth information have been developed and have demonstrated potential for reducing search significantly by identifying areas which have a high probability of being productive. Three of the parameters utilized by the model, chlorophyll-a, sea surface temperature, and turbidity have been inferred from aircraft sensor data. Cloud cover and delayed receipt have inhibited the use of Skylab data. The first step toward establishing the feasibility of utilizing remotely sensed data to assess amd monitor the distribution of ocean gamefish has been taken with the successful identification of fisheries significant oceanographic parameters and the demonstration of the capability of measuring most of these parameters remotely.

The impact of using area-averaged land surface properties —topography, vegetation condition, soil wetness—in calculations of intermediate scale (approximately 10 km 2) surface-atmosphere heat and moisture fluxes

NASA Astrophysics Data System (ADS)

Sellers, Piers J.; Heiser, Mark D.; Hall, Forrest G.; Verma, Shashi B.; Desjardins, Raymond L.; Schuepp, Peter M.; Ian MacPherson, J.

1997-03-01

It is commonly assumed that biophysically based soil-vegetation-atmosphere transfer (SVAT) models are scale-invariant with respect to the initial boundary conditions of topography, vegetation condition and soil moisture. In practice, SVAT models that have been developed and tested at the local scale (a few meters or a few tens of meters) are applied almost unmodified within general circulation models (GCMs) of the atmosphere, which have grid areas of 50-500 km 2. This study, which draws much of its substantive material from the papers of Sellers et al. (1992c, J. Geophys. Res., 97(D17): 19033-19060) and Sellers et al. (1995, J. Geophys. Res., 100(D12): 25607-25629), explores the validity of doing this. The work makes use of the FIFE-89 data set which was collected over a 2 km × 15 km grassland area in Kansas. The site was characterized by high variability in soil moisture and vegetation condition during the late growing season of 1989. The area also has moderate topography. The 2 km × 15 km 'testbed' area was divided into 68 × 501 pixels of 30 m × 30 m spatial resolution, each of which could be assigned topographic, vegetation condition and soil moisture parameters from satellite and in situ observations gathered in FIFE-89. One or more of these surface fields was area-averaged in a series of simulation runs to determine the impact of using large-area means of these initial or boundary conditions on the area-integrated (aggregated) surface fluxes. The results of the study can be summarized as follows: 1. analyses and some of the simulations indicated that the relationships describing the effects of moderate topography on the surface radiation budget are near-linear and thus largely scale-invariant. The relationships linking the simple ratio vegetation index ( SR), the canopy conductance parameter (▽ F) and the canopy transpiration flux are also near-linear and similarly scale-invariant to first order. Because of this, it appears that simple area-averaging operations can be applied to these fields with relatively little impact on the calculated surface heat flux. 2. The relationships linking surface and root-zone soil wetness to the soil surface and canopy transpiration rates are non-linear. However, simulation results and observations indicate that soil moisture variability decreases significantly as an area dries out, which partially cancels out the effects of these non-linear functions.In conclusion, it appears that simple averages of topographic slope and vegetation parameters can be used to calculate surface energy and heat fluxes over a wide range of spatial scales, from a few meters up to many kilometers at least for grassland sites and areas with moderate topography. Although the relationships between soil moisture and evapotranspiration are non-linear for intermediate soil wetnesses, the dynamics of soil drying act to progressively reduce soil moisture variability and thus the impacts of these non-linearities on the area-averaged surface fluxes. These findings indicate that we may be able to use mean values of topography, vegetation condition and soil moisture to calculate the surface-atmosphere fluxes of energy, heat and moisture at larger length scales, to within an acceptable accuracy for climate modeling work. However, further tests over areas with different vegetation types, soils and more extreme topography are required to improve our confidence in this approach.

Estimating Global Impervious Surface based on Social-economic Data and Satellite Observations

NASA Astrophysics Data System (ADS)

Zeng, Z.; Zhang, K.; Xue, X.; Hong, Y.

2016-12-01

Impervious surface areas around the globe are expanding and significantly altering the surface energy balance, hydrology cycle and ecosystem services. Many studies have underlined the importance of impervious surface, r from hydrological modeling to contaminant transport monitoring and urban development estimation. Therefore accurate estimation of the global impervious surface is important for both physical and social sciences. Given the limited coverage of high spatial resolution imagery and ground survey, using satellite remote sensing and geospatial data to estimate global impervious areas is a practical approach. Based on the previous work of area-weighted imperviousness for north branch of the Chicago River provided by HDR, this study developed a method to determine the percentage of impervious surface using latest global land cover categories from multi-source satellite observations, population density and gross domestic product (GDP) data. Percent impervious surface at 30-meter resolution were mapped. We found that 1.33% of the CONUS (105,814 km2) and 0.475% of the land surface (640,370km2) are impervious surfaces. To test the utility and practicality of the proposed method, National Land Cover Database (NLCD) 2011 percent developed imperviousness for the conterminous United States was used to evaluate our results. The average difference between the derived imperviousness from our method and the NLCD data across CONUS is 1.14%, while difference between our results and the NLCD data are within ±1% over 81.63% of the CONUS. The distribution of global impervious surface map indicates that impervious surfaces are primarily concentrated in China, India, Japan, USA and Europe where are highly populated and/or developed. This study proposes a straightforward way of mapping global imperviousness, which can provide useful information for hydrologic modeling and other applications.

Soil moisture status estimation over Three Gorges area with Landsat TM data based on temperature vegetation dryness index

NASA Astrophysics Data System (ADS)

Xu, Lina; Niu, Ruiqing; Li, Jiong; Dong, Yanfang

2011-12-01

Soil moisture is the important indicator of climate, hydrology, ecology, agriculture and other parameters of the land surface and atmospheric interface. Soil moisture plays an important role on the water and energy exchange at the land surface/atmosphere interface. Remote sensing can provide information on large area quickly and easily, so it is significant to do research on how to monitor soil moisture by remote sensing. This paper presents a method to assess soil moisture status using Landsat TM data over Three Gorges area in China based on TVDI. The potential of Temperature- Vegetation Dryness Index (TVDI) from Landsat TM data in assessing soil moisture was investigated in this region. After retrieving land surface temperature and vegetation index a TVDI model based on the features of Ts-NDVI space is established. And finally, soil moisture status is estimated according to TVDI. It shows that TVDI has the advantages of stability and high accuracy to estimating the soil moisture status.

Crumpled Nitrogen-Doped Graphene for Supercapacitors with High Gravimetric and Volumetric Performances.

PubMed

Wang, Jie; Ding, Bing; Xu, Yunling; Shen, Laifa; Dou, Hui; Zhang, Xiaogang

2015-10-14

Graphene is considered a promising electrochemical capacitors electrode material due to its high surface area and high electrical conductivity. However, restacking interactions between graphene nanosheets significantly decrease the ion-accessible surface area and impede electronic and ionic transfer. This would, in turn, severely hinder the realization of high energy density. Herein, we report a strategy for preparation of few-layer graphene material with abundant crumples and high-level nitrogen doping. The two-dimensional graphene nanosheets (CNG) feature high ion-available surface area, excellent electronic and ion transfer properties, and high packing density, permitting the CNG electrode to exhibit excellent electrochemical performance. In ionic liquid electrolyte, the CNG electrode exhibits gravimetric and volumetric capacitances of 128 F g(-1) and 98 F cm(-3), respectively, achieving gravimetric and volumetric energy densities of 56 Wh kg(-1) and 43 Wh L(-1). The preparation strategy described here provides a new approach for developing a graphene-based supercapacitor with high gravimetric and volumetric energy densities.

Nanoparticle flotation collectors--the influence of particle softness.

PubMed

Yang, Songtao; Razavizadeh, Bi Bi Marzieh; Pelton, Robert; Bruin, Gerard

2013-06-12

The ability of polymeric nanoparticles to promote glass bead and pentlandite (Pn, nickel sulfide mineral) attachment to air bubbles in flotation was measured as a function of the nanoparticle glass transition temperature using six types of nanoparticles based on styrene/N-butylacrylate copolymers. Nanoparticle size, surface charge density, and hydrophobicity were approximately constant over the series. The ability of the nanoparticles to promote air bubble attachment and perform as flotation collectors was significantly greater for softer nanoparticles. We propose that softer nanoparticles were more firmly attached to the glass beads or mineral surface because the softer particles had a greater glass/polymer contact areas and thus stronger overall adhesion. The diameters of the contact areas between polymeric nanoparticles and glass surfaces were estimated with the Young-Laplace equation for soft, liquidlike particles, whereas JKR adhesion theory was applied to the harder polystyrene particles. The diameters of the contact areas were estimated to be more than an order of magnitude greater for the soft particles compared to harder polystyrene particles.

Fiber-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2016-09-06

A fiber-based adsorbent and a related method of manufacture are provided. The fiber-based adsorbent includes polymer fibers with grafted side chains and an increased surface area per unit weight over known fibers to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. The polymer fibers include a circular morphology in some embodiments, having a mean diameter of less than 15 microns, optionally less than about 1 micron. In other embodiments, the polymer fibers include a non-circular morphology, optionally defining multiple gear-shaped, winged-shaped or lobe-shaped projections along the length of the polymer fibers. A method for forming the fiber-based adsorbents includes irradiating high surface area polymer fibers, grafting with polymerizable reactive monomers, reacting the grafted fibers with hydroxylamine, and conditioning with an alkaline solution. High surface area fiber-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Fiber-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J; Dai, Sheng; Oyola, Yatsandra

2014-05-13

A fiber-based adsorbent and a related method of manufacture are provided. The fiber-based adsorbent includes polymer fibers with grafted side chains and an increased surface area per unit weight over known fibers to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. The polymer fibers include a circular morphology in some embodiments, having a mean diameter of less than 15 microns, optionally less than about 1 micron. In other embodiments, the polymer fibers include a non-circular morphology, optionally defining multiple gear-shaped, winged-shaped or lobe-shaped projections along the length of the polymer fibers. A method for forming the fiber-based adsorbents includes irradiating high surface area polymer fibers, grafting with polymerizable reactive monomers, reacting the grafted fibers with hydroxylamine, and conditioning with an alkaline solution. High surface area fiber-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Solar Insolation Effect on the Local Distribution of Lunar Hydroxyl

NASA Astrophysics Data System (ADS)

Kim, Suyeon; Yi, Yu; Hong, Ik-Seon; Sohn, Jongdae

2018-03-01

Moon mineralogy mapper (M3)'s work proved that the moon is not completely dry but has some hydroxyl/water. M3's data confirmed that the amount of hydroxyl on the lunar surface is inversely related to the measured signal brightness, suggesting the lunar surface is sensitive to temperature by solar insolation. We tested the effect of solar insolation on the local distribution of hydroxyl by using M3 data, and we found that most craters had more hydroxyl in shade areas than in sunlit areas. This means that the local distribution of hydroxyl is absolutely influenced by the amount of sunshine. We investigated the factors affecting differences in hydroxyl; we found that the higher the latitude, the larger the difference during daytime. We also measured the pyroxene content and found that pyroxene affects the amount of hydroxyl, but it does not affect the difference in hydroxyl between sunlit and shaded areas. Therefore, we confirmed that solar insolation plays a significant role in the local distribution of hydroxyl, regardless of surface composition.

Modeling Nonresident Seabird Foraging Distributions to Inform Ocean Zoning in Central California.

PubMed

Studwell, Anna J; Hines, Ellen; Elliott, Meredith L; Howar, Julie; Holzman, Barbara; Nur, Nadav; Jahncke, Jaime

2017-01-01

Seabird aggregations at sea have been shown to be associated with concentrations of prey. Previous research identified Central California as a highly used foraging area for seabirds, with locally breeding seabirds foraging close to their colonies on Southeast Farallon Island. Herein, we focus on nonresident (i.e. non-locally breeding) seabird species off of Central California. We hypothesized that high-use foraging areas for nonresident seabirds would be influenced by oceanographic and bathymetric factors and that spatial and temporal distributions would be similar within planktivorous and generalist foraging guilds but would differ between them. With data collected by the Applied California Current Ecosystem Studies (ACCESS) partnership during cruises between April and October from 2004-2013, we developed generalized linear models to identify high-use foraging areas for each of six nonresident seabird species. The four generalist species are Phoebastria nigripes (black-footed albatross), Ardenna griseus (sooty shearwater), Ardenna creatopus (pink-footed shearwater), and Fulmarus glacialis (northern fulmar). The two planktivorous species are Phalaropus lobatus (red-necked phalarope) and Phalaropus fulicarius (red phalarope). Sea surface temperature was significant for generalist species and sea surface salinity was important for planktivorous species. The distance to the 200-m isobath was significant in five of six models, Pacific Decadal Oscillation with a 3-month lag in four models, and sea surface fluorescence, the distance to Cordell Bank, and depth in three models. We did not find statistically significant differences between distributions of individual seabird species within a foraging guild or between guilds, with the exception of the sooty shearwater. Model results for a multi-use seabird foraging area highlighted the continental shelf break, particularly within the vicinity of Cordell Bank, as the highest use areas as did Marxan prioritization. Our research methods can be implemented elsewhere to identify critical habitat that needs protection as human development pressures continue to expand to the ocean.

Empirical correlation between hydrophobic free energy and aqueous cavity surface area

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

Reynolds, J.A.; Gilbert, D.B.; Tanford, C.

1974-08-01

The unitary free energy of transfer of a hydrocarbon molecule from a hydrocarbon solvent to an aqueous medium is a measure of the hydrophobic interaction in the aqueous medium. We have reexamined available data on this phenomenon and have confirmed that the free energy for saturated hydrocarbons is proportional to the surface area of the cavity created by the solute in the aqueous solution, with the same proportionality constant for linear, branched, and cyclic hydrocarbon molecules. The numerical value of the proportionality constant is uncertain because absolute and self-consistent area measurements are not available. We estimate that it falls betweenmore » 20 and 25 cal/mole per Angstrom/sup 2/ at 25/sup 0/ (for areas measured at the distance of closest approach of water molecules), which is significantly less than the figure of 33 cal/mole per Angstrom/sup 2/ that has been assigned to the same parameter by Hermann.« less

Estimation of the fractional coverage of rainfall in climate models

NASA Technical Reports Server (NTRS)

Eltahir, E. A. B.; Bras, R. L.

1993-01-01

The fraction of the grid cell area covered by rainfall, mu, is an essential parameter in descriptions of land surface hydrology in climate models. A simple procedure is presented for estimating this fraction, based on extensive observations of storm areas and rainfall volumes. Storm area and rainfall volume are often linearly related; this relation can be used to compute the storm area from the volume of rainfall simulated by a climate model. A formula is developed for computing mu, which describes the dependence of the fractional coverage of rainfall on the season of the year, the geographical region, rainfall volume, and the spatial and temporal resolution of the model. The new formula is applied in computing mu over the Amazon region. Significant temporal variability in the fractional coverage of rainfall is demonstrated. The implications of this variability for the modeling of land surface hydrology in climate models are discussed.

The impact of climate and composition on playa surface roughness: Investigation of atmospheric mineral dust emission mechanisms

NASA Astrophysics Data System (ADS)

Tollerud, H. J.; Fantle, M. S.

2011-12-01

Atmospheric mineral dust has a wide range of impacts, including the transport of elements in geochemical cycles, health hazards from small particles, and climate forcing via the reflection of sunlight from dust particles. In particular, the mineral dust component of climate forcing is one of the most uncertain elements in the IPCC climate forcing summary. Mineral dust is also an important component of geochemical cycles. For instance, dust inputs to the ocean potentially affect the iron cycle by stimulating natural iron fertilization, which could then modify climate via the biological pump. Also dust can transport nutrients over long distances and fertilize nutrient-poor regions, such as island ecosystems or the Amazon rain forest. However, there are still many uncertainties in quantifying dust emissions from source regions. One factor that influences dust emission is surface roughness and texture, since a weak, unconsolidated surface texture is more easily ablated by wind than a strong, hard crust. We are investigating the impact of processes such as precipitation, groundwater evaporation, and wind on surface roughness in a playa dust source region. We find that water has a significant influence on surface roughness. We utilize ESA's Advanced Synthetic Aperture Radar (ASAR) instrument to measure roughness in the playa. A map of roughness indicates where the playa surface is smooth (on the scale of centimeters) and potentially very strong, and where it is rough and might be more sensitive to disturbance. We have analyzed approximately 40 ASAR observations of the Black Rock Desert from 2007-2011. In general, the playa is smoother and more variable over time relative to nearby areas. There is also considerable variation within the playa. While the playa roughness maps changed significantly between summers and between observations during the winters, over the course of each summer, the playa surface maintained essentially the same roughness pattern. This suggests that there were no active processes during the summers that changed surface roughness. Images from NASA's MODIS instrument (1640 nm, band 6) delineate winter flooding on the playa. Areas of water in the winter tend to be smoother in the summer. In particular, a smooth area of the play in summer 2010 aligns very closely with ponded water in February 2010. This indicates that standing water disrupts the playa surface, reducing roughness. We also compared the distribution of surface roughness across the playa to playa composition. X-ray diffraction (XRD) of samples from the Black Rock Desert demonstrates that the playa surface is composed of approximately 30% quartz, 45% clays, 10% calcite, and 5% halite. Calcite and halite concentrations vary significantly between samples. We produced a map of calcite concentration in the Black Rock Desert based on hyperspectral data from NASA's EO-1 Hyperion instrument. We find that calcite concentrations are higher in smooth areas that have been inundated by water. Without an understanding of the surface processes associated with dust emission, it is difficult to model atmospheric dust, especially in the past or future when there is much less data for an empirical dust model.

Nanoscale silver-assisted wet etching of crystalline silicon for anti-reflection surface textures.

PubMed

Li, Rui; Wang, Shuling; Chuwongin, Santhad; Zhou, Weidong

2013-01-01

We report here an electro-less metal-assisted chemical etching (MacEtch) process as light management surface-texturing technique for single crystalline Si photovoltaics. Random Silver nanostructures were formed on top of the Si surface based on the thin film evaporation and annealing process. Significant reflection reduction was obtained from the fabricated Si sample, with approximately 2% reflection over a wide spectra range (300 to 1050 nm). The work demonstrates the potential of MacEtch process for anti-reflection surface texture fabrication of large area, high efficiency, and low cost thin film solar cell.

Changing spatial patterns of evapotranspiration and deep drainage in response to the interactions among impervious surface arrangement, soil characteristics, and weather on a residential parcel.

NASA Astrophysics Data System (ADS)

Voter, C. B.; Steven, L. I.

2015-12-01

The introduction impervious surfaces in urban areas is a key driver of hydrologic change. It is now well understood that the amount of "effective" impervious area directly connected to the storm sewer network is a better indicator of hydrologic behavior than the total amount of impervious area. Most studies in urban hydrology have focused on the relationship between impervious connectivity and stormwater runoff or other surface water flows, with the result that the effect on subsurface flow is not as well understood. In the field, we observe differences in soil moisture availability that are dependent on proximity to impervious features and significant from a root water uptake perspective, which indicates that parcel-scale subsurface and plant water fluxes may also be sensitive to fine-scaled heterogeneity in impervious surface arrangement and connectivity. We use ParFlow with CLM, a watershed model with fully integrated variably-saturated subsurface flow, overland flow, and land-surface processes, to explore the extent to which soil moisture, evapotranspiration, and deep drainage vary under various impervious surface arrangement and soil condition scenarios, as well as under a range of precipitation regimes. We investigate the effect of several impervious surface and soil characteristics, including general lot layout, downspout disconnect, and direction of driveway/sidewalk slope, and soil compaction. We show that that some impervious connectivity schemes transfer more water from impervious areas to pervious ones and promote localized recharge by developing well-defined, fast-moving wetting fronts that are able to penetrate the root zone. Enhanced infiltration is translated more directly to recharge in normal to wet years but partitioned more often to transpiration in dry years, leading to a nonlinear relationship among precipitation, runoff and recharge.

Terrain-Moisture Classification Using GPS Surface-Reflected Signals

NASA Technical Reports Server (NTRS)

Grant, Michael S.; Acton, Scott T.; Katzberg, Stephen J.

2006-01-01

In this study we present a novel method of land surface classification using surface-reflected GPS signals in combination with digital imagery. Two GPS-derived classification features are merged with visible image data to create terrain-moisture (TM) classes, defined here as visibly identifiable terrain or landcover classes containing a surface/soil moisture component. As compared to using surface imagery alone, classification accuracy is significantly improved for a number of visible classes when adding the GPS-based signal features. Since the strength of the reflected GPS signal is proportional to the amount of moisture in the surface, use of these GPS features provides information about the surface that is not obtainable using visible wavelengths alone. Application areas include hydrology, precision agriculture, and wetlands mapping.

Physical Activation of Oil Palm Empty Fruit Bunch via CO2 Activation Gas for CO2 Adsorption

NASA Astrophysics Data System (ADS)

Joseph, C. G.; Quek, K. S.; Daud, W. M. A. W.; Moh, P. Y.

2017-06-01

In this study, different parameters for the preparation of activated carbon were investigated for their yield and CO2 capture capabilities. The activated carbon was prepared from Oil Palm Empty Fruit Bunch (OPEFB) via a 2-step physical activation process. The OPEFB was pyrolyzed under inert conditions at 500 °C and activated via CO2. A 2-factorial design was employed and the effects of activation temperature, activation dwell time and gas flow rate on yield and CO2 capture capabilities were compared and studied. The yield obtained ranged from between 20 - 26, whereby the temperature was determined to be the most significant factor in influencing CO2 uptake. The CO2 capture capacity was determined using Temperature Programmed Desorption (TPD) technique. The CO2 uptake of EFB activated carbon achieved was between 1.85 - 2.09 mmol/g. TPD analysis has shown that the surface of AC were of basic nature. AC was found to be able to withhold the CO2 up to 663°C before maximum desorption occurs. The surface area and pore size of OPEFB obtained from BET analysis is 2.17 m2 g-1 and 0.01 cm3 g-1. After activation, both surface area and pore size increased with a maximum observed surface area and pore size of 548.07 m2 g-1 and 0.26 cm3 g-1. Surface morphology, functional groups, pore size and surface area were analyzed using SEM, FT-IR, TPD and BET.

Calcium phosphate ceramics in drug delivery

NASA Astrophysics Data System (ADS)

Bose, Susmita; Tarafder, Solaiman; Edgington, Joe; Bandyopadhyay, Amit

2011-04-01

Calcium phosphate (CaP) particulates, cements and scaffolds have attracted significant interest as drug delivery vehicles. CaP systems, including both hydroxyapaptite and tricalcium phosphates, possess variable stoichiometry, functionality and dissolution properties which make them suitable for cellular delivery. Their chemical similarity to bone and thus biocompatibility, as well as variable surface charge density contribute to their controlled release properties. Among specific research areas, nanoparticle size, morphology, surface area due to porosity, and chemistry controlled release kinetics are the most active. This article discusses CaP systems in their particulate, cements, and scaffold forms for drug, protein, and growth factor delivery toward orthopedic and dental applications.

A study of variation characteristics of Gobi broadband emissivity based on field observational experiments in northwestern China

NASA Astrophysics Data System (ADS)

Zheng, Zhi-yuan; Wei, Zhi-gang; Wen, Zhi-ping; Dong, Wen-jie; Li, Zhen-chao; Wen, Xiao-hang; Zhu, Xian; Chen, Chen; Hu, Shan-shan

2018-02-01

Land surface emissivity is a significant variable in energy budgets, land cover assessments, and environment and climate studies. However, the assumption of an emissivity constant is being used in Gobi broadband emissivity (GbBE) parameterization scheme in numerical models because of limited knowledge surrounding the spatiotemporal variation characteristics of GbBE. To address this issue, we analyzed the variation characteristics of GbBE and possible impact factor-surface soil moisture based on long-term continuous and high temporal resolution field observational experiments over a typical Gobi underlying surface in arid and semiarid areas in northwestern China. The results indicate that GbBE has obvious daily and diurnal variation features, especially diurnal cycle characteristics. The multi-year average of the daily average of GbBE is in the range of 0.932 to 0.970 with an average of 0.951 ± 0.008, and the average diurnal GbBE is in the range of 0.880 to 0.940 with an average of 0.906 ± 0.018. GbBE varies with surface soil moisture content. We observed a slight decrease in GbBE with an increase in soil moisture, although this change was not very obvious because of the low soil moisture in this area. Nevertheless, we think that soil moisture must be one of the most significant impact factors on GbBE in arid and semiarid areas. Soil moisture must be taken into account into the parameterization schemes of bare soil broadband emissivity in land surface models. Additional field experiments and studies should be carried out in order to clarify this issue.

Simulated effects of development on regional ground-water/surface-water interactions in the northern Coastal Plain of New Jersey

NASA Astrophysics Data System (ADS)

Pucci, Amleto A.; Pope, Daryll A.

1995-05-01

Stream flow in the Coastal Plain of New Jersey is primarily controlled by ground-water discharge. Ground-water flow in a 400 square mile area (1035 km 2) of the Potomac-Raritan-Magothy aquifer system (PRMA) in the northern Coastal Plain of New Jersey was simulated to examine development effects on water resources. Simulations showed that historical development caused significant capture of regional ground-water discharge to streams and wetlands. The Cretaceous PRMA primarily is composed of fine to coarse sand, clays and silts which form the Upper and Middle aquifers and their confining units. The aquifer outcrops are the principal areas of recharge and discharge for the regional flow system and have many traversing streams and surface-water bodies. A quasi-three-dimensional numerical model that incorporated ground-water/surface-water interactions and boundary flows from a larger regional model was used to represent the PRMA. To evaluate the influence of ground-water development on interactions in different areas, hydrogeologically similar and contiguous model stream cells were aggregated as 'stream zones'. The model representation of surface-water and ground-water interaction was limited in the areas of confining unit outcrops and because of this, simulated ground-water discharge could not be directly compared with base flow. Significant differences in simulated ground-water and surface-water interactions between the predevelopment and developed system, include; (1) redistribution of recharge and discharge areas; (2) reduced ground-water discharge to streams. In predevelopment, the primary discharge for the Upper and Middle aquifers is to low-lying streams and wetlands; in the developed system, the primary discharge is to ground-water withdrawals. Development reduces simulated ground-water discharge to streams in the Upper Aquifer from 61.4 to 10% of the Upper Aquifer hydrologic budget (28.9%, if impounded stream flow is included). Ground-water discharge to streams in the Middle Aquifer decreases from 80.0 to 22% of the Middle Aquifer hydrologic budget. The utility of assessing ground-water/surface-water interaction in a regional hydrogeologic system by simulation responses to development is demonstrated and which can compensate for lack of long-term stream-gaging data in determining management decisions.

Lp-dual affine surface area

NASA Astrophysics Data System (ADS)

Wei, Wang; Binwu, He

2008-12-01

According to the notion of Lp-affine surface area by Lutwak, in this paper, we introduce the concept of Lp-dual affine surface area. Further, we establish the affine isoperimetric inequality and the Blaschke-Santaló inequality for Lp-dual affine surface area. Besides, the dual Brunn-Minkowski inequality for Lp-dual affine surface area is presented.

A new treatment of hypertrophic and keloid scars with combined triamcinolone and verapamil: a retrospective study.

PubMed

Kant, S B; van den Kerckhove, E; Colla, C; Tuinder, S; van der Hulst, R R W J; Piatkowski de Grzymala, A A

2018-01-01

Since the management of keloid and hypertrophic scars still remains a difficult clinical problem, there is need for adequate, effective therapy. In this study, we explored for the first time the efficacy and the potential synergetic effect of combined triamcinolone and verapamil for the treatment of hypertrophic and keloid scars. The objective was to assess the efficacy of combined intralesional triamcinolone and verapamil therapy for hypertrophic and keloid scars. Fifty-eight patients with hypertrophic scars ( n  = 31) and keloid scars ( n  = 27) were included. A specific injection therapy scheme was applied. Five follow-up moments were chosen, with a maximum follow-up of nearly 2 years. The effects of combination therapy on scar pliability, thickness, relief, vascularization, surface area, pain, and pruritus were examined by means of the Patient and Observer Scar Assessment Scale (POSAS). Our results reveal a fast and abiding improvement of both keloid and hypertrophic scars after treatment with the combination therapy. All POSAS components showed a reduction in scar score, while scar relief, pain, itchiness, and surface area improved significantly ( P  < 0.05) in keloids. Significant improvement in hypertrophic scars was found in scar pigmentation, vascularization, pliability, thickness, pain, and surface area. Overall POSAS scores revealed statistically significant decreases between baseline and 3-4 months, 4-6 months, and >12 months after start of therapy in both keloids and hypertrophic scars. This study reveals that combined therapy of triamcinolone and verapamil results in overall significant scar improvement with a long-term stable result.Level of evidence: Level IV, therapeutic study.

[Anatomical and radiological studies on additional mandible teeth anesthesia considering innervation variability].

PubMed

Tarasenko, S V; Dydykin, S S; Kuzin, A V

2013-01-01

The paper presents studies on nutritional foramina of the mandible. Some nutritional foramina located in the frontal mandibular region on the lingual surface and containing significant blood vessels and nerves are found to be more typical for teeth-bearing mandible. In retromolar area in case of third molars presence intraosseous canals were revealed leading to inferior alveolar nerve canal. One should consider intraligamental and lingual anesthesia by lower incisors extraction. Intraosseous anesthesia and retromolar area infiltration significantly increase anesthesia efficiency by third molar extraction.

Polybrominated diphenyl ethers in surface soils from e-waste recycling areas and industrial areas in South China: concentration levels, congener profile, and inventory.

PubMed

Gao, Shutao; Hong, Jianwen; Yu, Zhiqiang; Wang, Jingzhi; Yang, Guoyi; Sheng, Guoying; Fu, Jiamo

2011-12-01

Polybrominated diphenyl ethers (PBDEs) were determined in 60 surface soils from two e-waste recycling sites (Qingyuan and Guiyu, China) and their surrounding areas to assess the extent and influence of PBDEs from e-waste recycling sites on the surrounding areas. A total of 32 surface soils from industrial areas in South China were also investigated for comparison. The mean concentrations of total PBDEs in the e-waste recycling sites of Guiyu and Qingyuan were 2,909 and 3,230 ng/g dry weight, respectively, whereas the PBDE concentrations decreased dramatically (1-2 orders of magnitude) with increasing distance from the recycling site, suggesting that the e-waste recycling activities were the major source of PBDEs in the surrounding areas. Decabromodiphenyl ethers accounted for 77.0 to 85.8% of total PBDEs in e-waste recycling areas, whereas it accounted for 90.2% in industrial areas. Principal component analysis showed that the major source of PBDEs in e-waste recycling areas were a combination of penta-, octa-, and deca-BDE commercial formulations, whereas deca-BDE commercial formulations were the major source of PBDE congeners in industrial areas. The inventories of PBDEs gave preliminary estimates of 6.22 tons and 13.4 tons for the e-waste recycling areas and industrial areas. The results suggested that significantly higher PBDEs in the e-waste recycling sites have already affected surrounding areas negatively within a relatively large distance. Because of the environmental persistence, bioaccumulation, and toxicity of PBDEs, improving the recycling techniques employed at such facilities and developing e-waste management policies are necessary. Copyright © 2011 SETAC.

Gaussian process based intelligent sampling for measuring nano-structure surfaces

NASA Astrophysics Data System (ADS)

Sun, L. J.; Ren, M. J.; Yin, Y. H.

2016-09-01

Nanotechnology is the science and engineering that manipulate matters at nano scale, which can be used to create many new materials and devices with a vast range of applications. As the nanotech product increasingly enters the commercial marketplace, nanometrology becomes a stringent and enabling technology for the manipulation and the quality control of the nanotechnology. However, many measuring instruments, for instance scanning probe microscopy, are limited to relatively small area of hundreds of micrometers with very low efficiency. Therefore some intelligent sampling strategies should be required to improve the scanning efficiency for measuring large area. This paper presents a Gaussian process based intelligent sampling method to address this problem. The method makes use of Gaussian process based Bayesian regression as a mathematical foundation to represent the surface geometry, and the posterior estimation of Gaussian process is computed by combining the prior probability distribution with the maximum likelihood function. Then each sampling point is adaptively selected by determining the position which is the most likely outside of the required tolerance zone among the candidates and then inserted to update the model iteratively. Both simulationson the nominal surface and manufactured surface have been conducted on nano-structure surfaces to verify the validity of the proposed method. The results imply that the proposed method significantly improves the measurement efficiency in measuring large area structured surfaces.

(Quasi-) 2D aggregation of polystyrene-b-dextran at the air-water interface.

PubMed

Bosker, Wouter T E; Cohen Stuart, Martien A; Norde, Willem

2013-02-26

Polystyrene-b-dextran (PS-b-Dextran) copolymers can be used to prepare dextran brushes at solid surfaces, applying Langmuir-Blodgett deposition. When recording the interfacial pressure versus area isotherms of a PS-b-Dextran monolayer, time-dependent hysteresis was observed upon compression and expansion. We argue that this is due to (quasi-) 2D aggregation of the copolymer at the air-water surface, with three contributions. First, at large area per molecule, a zero surface pressure is measured; we ascribe this to self-assembly of block copolymers into surface micelles. At intermediate area we identify a second regime ("desorption regime") where aggregation into large patches occurs due to van der Waals attraction between PS blocks. At high surface pressure ("brush regime") we observe hysteretic behavior attributed to H-bonding between dextran chains. When compared to hysteresis of other amphiphilic diblock copolymers (also containing PS, e.g., polystyrene-b-poly(ethylene oxide)) a general criterion can be formulated concerning the extent of hysteresis: when the hydrophobic (PS) block is of equal size as (or bigger than) the hydrophilic block, the hysteresis is maximal. The (quasi-) 2D aggregation of PS-b-Dextran has significant implications for the preparation of dextran brushes at solid surfaces using Langmuir-Blodgett deposition. For each grafting density the monolayer needs to relax, up to several hours, prior to transfer.

The effect of surface and season on playground injury rates

PubMed Central

Branson, Lara Joan; Latter, John; Currie, Gillian R; Nettel-Aguirre, Alberto; Embree, Tania; Hagel, Brent Edward

2012-01-01

OBJECTIVE: To examine the effect of season on playground surface injury rates. METHODS: Injuries were identified through student incident report forms used in school districts in Calgary (Alberta) and the surrounding area. Playground surface exposure data were estimated based on school enrollment. RESULTS: A total of 539 injuries were reported during the 2007/2008 school year. Abrasions, bruises and inflammation were the most frequently reported injuries. The head, neck or face were most commonly injured. Injury rates per 1000 student days ranged between 0.018 (rubber crumb in spring) and 0.08 (poured-in-place and natural rock in the fall). Rubber crumb surfacing, compared with natural rock, had a significantly lower rate of injury in the spring, but no other season-surface comparisons were statistically significant. CONCLUSIONS: Rates of injury were similar for natural rock, poured-in-place, and crushed rock in the fall and winter. There was some evidence of a lower rate of injury on rubber crumb surfaces in the spring. PMID:24179416

Unexploded ordnance issues at Aberdeen Proving Ground: Background information

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

Rosenblatt, D.H.

1996-11-01

This document summarizes currently available information about the presence and significance of unexploded ordnance (UXO) in the two main areas of Aberdeen Proving Ground: Aberdeen Area and Edgewood Area. Known UXO in the land ranges of the Aberdeen Area consists entirely of conventional munitions. The Edgewood Area contains, in addition to conventional munitions, a significant quantity of chemical-munition UXO, which is reflected in the presence of chemical agent decomposition products in Edgewood Area ground-water samples. It may be concluded from current information that the UXO at Aberdeen Proving Ground has not adversely affected the environment through release of toxic substancesmore » to the public domain, especially not by water pathways, and is not likely to do so in the near future. Nevertheless, modest but periodic monitoring of groundwater and nearby surface waters would be a prudent policy.« less

Monitoring surface urban heat island formation in a tropical mountain city using Landsat data (1987-2015)

NASA Astrophysics Data System (ADS)

Estoque, Ronald C.; Murayama, Yuji

2017-11-01

Since it was first described about two centuries ago and due to its adverse impacts on urban ecological environment and the overall livability of cities, the urban heat island (UHI) phenomenon has been, and still is, an important research topic across various fields of study. However, UHI studies on cities in mountain regions are still lacking. This study aims to contribute to this endeavor by monitoring and examining the formation of surface UHI (SUHI) in a tropical mountain city of Southeast Asia -Baguio City, the summer capital of the Philippines- using Landsat data (1987-2015). Based on mean surface temperature difference between impervious surface (IS) and green space (GS1), SUHI intensity (SUHII) in the study area increased from 2.7 °C in 1987 to 3.4 °C in 2015. Between an urban zone (>86% impervious) and a rural zone (<10% impervious) along the urban-rural gradient, it increased from 4.0 °C in 1987 to 8.2 °C in 2015. These results are consistent with the rapid urbanization of the area over the same period, which resulted in a rapid expansion of impervious surfaces and substantial loss of green spaces. Together with landscape composition variables (e.g. fraction of IS), topographic variables (e.g. hillshade) can help explain a significant amount of spatial variations in surface temperature in the area (R2 = 0.56-0.85) (p < 0.001). The relative importance of the 'fraction of IS' variable also increased, indicating that its unique explanatory and predictive power concerning the spatial variations of surface temperature increases as the city size becomes bigger and SUHI gets more intense. Overall, these results indicate that the cool temperature of the study area being situated in a mountain region did not hinder the formation of SUHI. Thus, the formation and effects of UHIs, including possible mitigation and adaptation measures, should be considered in landscape planning for the sustainable urban development of the area.

Anatomy of the proximal tibiofibular joint and interosseous membrane, and their contributions to joint kinematics in below-knee amputations.

PubMed

Burkhart, Timothy A; Asa, Benjamin; Payne, Michael W C; Johnson, Marjorie; Dunning, Cynthia E; Wilson, Timothy D

2015-02-01

A result of below-knee amputations (BKAs) is abnormal motion that occurs about the proximal tibiofibular joint (PTFJ). While it is known that joint morphology may play a role in joint kinematics, this is not well understood with respect to the PTFJ. Therefore, the purposes of this study were: (i) to characterize the anatomy of the PTFJ and statistically analyze the relationships within the joint; and (ii) to determine the relationships between the PTFJ characteristics and the degree of movement of the fibula in BKAs. The PTFJ was characterized in 40 embalmed specimens disarticulated at the knee, and amputated through the mid-tibia and fibula. Four metrics were measured: inclination angle (angle at which the fibula articulates with the tibia); tibial and fibular articular surface areas; articular surface concavity and shape. The specimens were mechanically tested by applying a load through the biceps femoris tendon, and the degree of motion about the tibiofibular joint was measured. Regression analyses were performed to determine the relationships between the different PTFJ characteristics and the magnitude of fibular abduction. Finally, Pearson correlation analyses were performed on inclination angle and surface area vs. fibular kinematics. The inclination angle measured on the fibula was significantly greater than that measured on the tibia. This difference may be attributed to differences in concavity of the tibial and fibular surfaces. Surface area measured on the tibia and fibula was not statistically different. The inclination angle was not statistically correlated to surface area. However, when correlating fibular kinematics in BKAs, inclination angle was positively correlated to the degree of fibular abduction, whereas surface area was negatively correlated. The characteristics of the PTFJ dictate the amount of fibular movement, specifically, fibular abduction in BKAs. Predicting BKA complications based on PTFJ characteristics can lead to recommendations in treatment. © 2014 Anatomical Society.

Effect of electrode sub-micron surface feature size on current generation of Shewanella oneidensis in microbial fuel cells

NASA Astrophysics Data System (ADS)

Ye, Zhou; Ellis, Michael W.; Nain, Amrinder S.; Behkam, Bahareh

2017-04-01

Microbial fuel cells (MFCs) are envisioned to serve as compact and sustainable sources of energy; however, low current and power density have hindered their widespread use. Introduction of 3D micro/nanostructures on the MFC anode is known to improve its performance by increasing the surface area available for bacteria attachment; however, the role of the feature size remains poorly understood. To delineate the role of feature size from the ensuing surface area increase, nanostructures with feature heights of 115 nm and 300 nm, both at a height to width aspect ratio of 0.3, are fabricated in a grid pattern on glassy carbon electrodes (GCEs). Areal current densities and bacteria attachment densities of the patterned and unpatterned GCEs are compared using Shewanella oneidensis Δbfe in a three-electrode bioreactor. The 115 nm features elicit a remarkable 40% increase in current density and a 78% increase in bacterial attachment density, whereas the GCE with 300 nm pattern does not exhibit significant change in current density or bacterial attachment density. The current density dependency on feature size is maintained over the entire 160 h experiment. Thus, optimally sized surface features have a substantial effect on current production that is independent of their effect on surface area.

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.

Infrared Preheating to Enhance Interlayer Strength of Components Printed on the Big Area Additive Manufacturing (BAAM) System

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

Kishore, Vidya; Ajinjeru, Christine; Duty, Chad E

The Big Area Additive Manufacturing (BAAM) system has the capacity to print structures on the order of several meters at a rate exceeding 50 kg/h, thereby having the potential to significantly impact the production of components in automotive, aerospace and energy sectors. However, a primary issue that limits the functional use of such parts is mechanical anisotropy. The strength of printed parts across successive layers in the build direction (z-direction) is significantly lower than the corresponding in-plane strength (x-y directions). This is largely due to poor bonding between the printed layers as the lower layers cool below the glass transitionmore » temperature (Tg) before the next layer is deposited. This work explores the use of infrared heating to increase the surface temperature of the printed layer just prior to deposition of new material to improve the interlayer strength of the components. The material used in this study was acrylonitrile butadiene styrene (ABS) reinforced with 20% chopped carbon fiber by weight. Significant improvements in z-strength were observed for the parts whose surface temperature was increased from below Tg to close to or above Tg using infrared heating. Parameters such as print speed, nozzle diameter and extrusion temperature were also found to impact the heat input required to enhance interlayer adhesion without significantly degrading the polymer and compromising on surface finish.« less

Examination of Spectral Transformations on Spectral Mixture Analysis

NASA Astrophysics Data System (ADS)

Deng, Y.; Wu, C.

2018-04-01

While many spectral transformation techniques have been applied on spectral mixture analysis (SMA), few study examined their necessity and applicability. This paper focused on exploring the difference between spectrally transformed schemes and untransformed scheme to find out which transformed scheme performed better in SMA. In particular, nine spectrally transformed schemes as well as untransformed scheme were examined in two study areas. Each transformed scheme was tested 100 times using different endmember classes' spectra under the endmember model of vegetation- high albedo impervious surface area-low albedo impervious surface area-soil (V-ISAh-ISAl-S). Performance of each scheme was assessed based on mean absolute error (MAE). Statistical analysis technique, Paired-Samples T test, was applied to test the significance of mean MAEs' difference between transformed and untransformed schemes. Results demonstrated that only NSMA could exceed the untransformed scheme in all study areas. Some transformed schemes showed unstable performance since they outperformed the untransformed scheme in one area but weakened the SMA result in another region.

Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

PubMed

Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

2012-01-01

The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (p<0.01). The GC group presented a significantly lower peroxide passage than did GD and GE (p<0.01). It can be concluded that the hydrogen peroxide placed into the pulp chamber passed through the dental hard tissues, reaching the external surface and the periodontal tissue. The cementum surface was less permeable than were the dentin and enamel surfaces.

High reduction of interfacial charge recombination in colloidal quantum dot solar cells by metal oxide surface passivation.

PubMed

Chang, Jin; Kuga, Yuki; Mora-Seró, Iván; Toyoda, Taro; Ogomi, Yuhei; Hayase, Shuzi; Bisquert, Juan; Shen, Qing

2015-03-12

Bulk heterojunction (BHJ) solar cells based on colloidal QDs and metal oxide nanowires (NWs) possess unique and outstanding advantages in enhancing light harvesting and charge collection in comparison to planar architectures. However, the high surface area of the NW structure often brings about a large amount of recombination (especially interfacial recombination) and limits the open-circuit voltage in BHJ solar cells. This problem is solved here by passivating the surface of the metal oxide component in PbS colloidal quantum dot solar cells (CQDSCs). By coating thin TiO2 layers onto ZnO-NW surfaces, the open-circuit voltage and power conversion efficiency have been improved by over 40% in PbS CQDSCs. Characterization by transient photovoltage decay and impedance spectroscopy indicated that the interfacial recombination was significantly reduced by the surface passivation strategy. An efficiency as high as 6.13% was achieved through the passivation approach and optimization for the length of the ZnO-NW arrays (device active area: 16 mm2). All solar cells were tested in air, and exhibited excellent air storage stability (without any performance decline over more than 130 days). This work highlights the significance of metal oxide passivation in achieving high performance BHJ solar cells. The charge recombination mechanism uncovered in this work could shed light on the further improvement of PbS CQDSCs and/or other types of solar cells.

Assessment of a landfill methane emission screening method using an unmanned aerial vehicle mounted thermal infrared camera - A field study.

PubMed

Fjelsted, L; Christensen, A G; Larsen, J E; Kjeldsen, P; Scheutz, C

2018-05-28

An unmanned aerial vehicle (UAV)-mounted thermal infrared (TIR) camera's ability to delineate landfill gas (LFG) emission hotspots was evaluated in a field test at two Danish landfills (Hedeland landfill and Audebo landfill). At both sites, a test area of 100 m 2 was established and divided into about 100 measuring points. The relationship between LFG emissions and soil surface temperatures were investigated through four to five measuring campaigns, in order to cover different atmospheric conditions along with increasing, decreasing and stable barometric pressure. For each measuring campaign, a TIR image of the test area was obtained followed by the measurement of methane (CH 4 ) and carbon dioxide (CO 2 ) emissions at each measuring point, using a static flux chamber. At the same time, soil temperatures measured on the surface, at 5 cm and 10 cm depths, were registered. At the Hedeland landfill, no relationship was found between LFG emissions and surface temperatures. In addition, CH 4 emissions were very limited, on average 0.92-4.52 g CH 4  m -2  d -1 , and only measureable on the two days with decreasing barometric pressure. TIR images from Hedeland did not show any significant temperature differences in the test area. At the Audebo landfill, an area with slightly higher surface temperatures was found in the TIR images, and the same pattern with slightly higher temperatures was found at a depth of 10 cm. The main LFG emissions were found in the area with the higher surface temperatures. LFG emissions at Audebo were influenced significantly by changes in barometric pressure, and the average CH 4 emissions varied between 111 g m -2  d -1 and 314 g m -2  d -1 , depending on whether the barometric pressure gradient had increased or decreased, respectively. The temperature differences observed in the TIR images from both landfills were limited to between 0.7 °C and 1.2 °C. The minimum observable CH 4 emission for the TIR camera to identify an emission hotspot was 150 g CH 4  m -2  d -1 from an area of more than 1 m 2 . Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Texturing Carbon-carbon Composite Radiator Surfaces Utilizing Atomic Oxygen

NASA Technical Reports Server (NTRS)

Raack, Taylor

2004-01-01

Future space nuclear power systems will require radiator technology to dissipate excess heat created by a nuclear reactor. Large radiator fins with circulating coolant are in development for this purpose and an investigation of how to make them most efficient is underway. Maximizing the surface area while minimizing the mass of such radiator fins is critical for obtaining the highest efficiency in dissipating heat. Processes to develop surface roughness are under investigation to maximize the effective surface area of a radiator fin. Surface roughness is created through several methods including oxidation and texturing. The effects of atomic oxygen impingement on carbon-carbon surfaces are currently being investigated for texturing a radiator surface. Early studies of atomic oxygen impingement in low Earth orbit indicate significant texturing due to ram atomic oxygen. The surface morphology of the affected surfaces shows many microscopic cones and valleys which have been experimentally shown to increase radiation emittance. Further study of this morphology proceeded in the Long Duration Exposure Facility (LDEF). Atomic oxygen experiments on the LDEF successfully duplicated the results obtained from materials in spaceflight by subjecting samples to 4.5 eV atomic oxygen from a fixed ram angle. These experiments replicated the conical valley morphology that was seen on samples subjected to low Earth orbit.

Disinfection procedures: their efficacy and effect on dimensional accuracy and surface quality of an irreversible hydrocolloid impression material.

PubMed

Rentzia, A; Coleman, D C; O'Donnell, M J; Dowling, A H; O'Sullivan, M

2011-02-01

This study investigated the antibacterial efficacy and effect of 0.55% ortho-phthalaldehyde (Cidex OPA(®)) and 0.5% sodium hypochlorite (NaOCl) on the dimensional accuracy and surface quality of gypsum casts retrieved from an irreversible hydrocolloid impression material. A simulated clinical cast and technique was developed to compare the dimensional accuracy and surface quality changes of the test gypsum casts with controls. Dimensional accuracy measurements were completed between fixed points using a travelling microscope under low angle illumination at a magnification of ×3. Surface quality changes of "smooth" and "rough" areas on the cast were evaluated by means of optical profilometry. The efficacy of the disinfection procedures against Pseudomonas aeruginosa was evaluated by determining the number of colony forming units (cfu) recovered after disinfection of alginate discs inoculated with 1×10⁶cfu for defined intervals. The dimensional accuracy of the gypsum casts was not significantly affected by the disinfection protocols. Neither disinfectant solution nor immersion time had an effect on the surface roughness of the "smooth" area on the cast, however, a significant increase in surface roughness was observed with increasing immersion time for the "rough" surface. Complete elimination of viable Pseudomonas aeruginosa cells from alginate discs was obtained after 30 and 120 s immersion in Cidex OPA(®) and NaOCl, respectively. Immersion of irreversible hydrocolloid impressions in Cidex OPA(®) for 30 s was proved to be the most effective disinfection procedure. Copyright © 2010 Elsevier Ltd. All rights reserved.

Characterization of nanoporous shales with gas sorption

NASA Astrophysics Data System (ADS)

Joewondo, N.; Prasad, M.

2017-12-01

The understanding of the fluid flow in porous media requires the knowledge of the pore system involved. Fluid flow in fine grained shales falls under different regime than transport regime in conventional reservoir due to the different average pore sizes in the two materials; the average pore diameter of conventional sandstones is on the micrometer scale, while of shales can be as small as several nanometers. Mercury intrusion porosimetry is normally used to characterize the pores of conventional reservoir, however with increasingly small pores, the injection pressure required to imbibe the pores becomes infinitely large due to surface tension. Characterization of pores can be expressed by a pore size distribution (PSD) plot, which reflects distribution of pore volume or surface area with respect to pore size. For the case of nanoporous materials, the surface area, which serves as the interface between the rock matrix and fluid, becomes increasingly large and important. Physisorption of gas has been extensively studied as a method of nanoporous solid characterization (particularly for the application of catalysis, metal organic frameworks, etc). The PSD is obtained by matching the experimental result to the calculated theoretical result (using Density Functional Theory (DFT), a quantum mechanics based modelling method for molecular scale interactions). We present the challenges and experimental result of Nitrogen and CO2 gas sorption on shales with various mineralogy and the interpreted PSD obtained by DFT method. Our result shows significant surface area contributed by the nanopores of shales, hence the importance of surface area measurements for the characterization of shales.

Dynamics of spider glue adhesion: effect of surface energy and contact area

NASA Astrophysics Data System (ADS)

Amarpuri, Gaurav; Chen, Yizhou; Blackledge, Todd; Dhinojwala, Ali

Spider glue is a unique biological adhesive which is humidity responsive such that the adhesion continues to increase upto 100% relative humidity (RH) for some species. This is unlike synthetic adhesives that significantly drop in adhesion with an increase in humidity. However, most of adhesion data reported in literature have used clean hydrophilic glass substrate, unlike the hydrophobic, and charged insect cuticle surface that adheres to spider glue in nature. Previously, we have reported that the spider glue viscosity changes over five orders of magnitude with humidity. Here, we vary the surface energy and surface charge of the substrate to test the change in Larnioides cornutus spider glue adhesion with humidity. We find that an increase in both surface energy and surface charge density increases the droplet spreading and there exists an optimum droplet contact area where adhesion is maximized. Moreover, spider glue droplets act as reusable adhesive for low energy hydrophobic surface at the optimum humidity. These results explain why certain prey are caught more efficiently by spiders in their habitat. The mechanism by which spider species tune its glue adhesion for local prey capture can inspire new generation smart adhesives.

Comparison of the impact of scaler material composition on polished titanium implant abutment surfaces.

PubMed

Hasturk, Hatice; Nguyen, Daniel Huy; Sherzai, Homa; Song, Xiaoping; Soukos, Nikos; Bidlack, Felicitas B; Van Dyke, Thomas E

2013-08-01

The purpose of this study was to compare the impact of the removal of biofilm with hand scalers of different material composition on the surface of implant abutments by assessing the surface topography and residual plaque after scaling using scanning electron microscopy (SEM). Titanium implant analogs from 3 manufacturers (Straumann USA LLC, Andover, Maine, Nobel BioCare USA LLC, Yorba Linda, Cali, Astra Tech Implant Systems, Dentsply, Mölndal, Sweden) were mounted in stone in plastic vials individually with authentic prosthetic abutments. Plaque samples were collected from a healthy volunteer, inoculated into growth medium and incubated with the abutments anaerobically for 1 week. A blinded, calibrated hygienist performed scaling to remove the biofilm using 6 implant scalers (in triplicate), 1 scaler for 1 abutment. The abutments were mounted on an imaging stand and processed for SEM. Images were captured in 3 randomly designated areas of interest on each abutment. Analysis of the implant polished abutment surface and plaque area measurements were performed using ImageJ image analysis software. Surface alterations were characterized by the number, length, depth and the width of the scratches observed. Glass filled resin scalers resulted in significantly more and longer scratches on all 3 abutment types compared to other scalers, while unfilled resin scalers resulted in the least surface change (p < 0.05). Filled resin-graphite reinforced scalers, carbon fiber reinforced resin scalers and titanium scalers resulted in more superficial scratches compared to glass filled resin, as well as more scratches than unfilled resin. No statistically significant differences were found between scalers and abutments with regard to plaque removal. The impact of scalers on implant abutment surfaces varies between abutment types presumably due to different surface characteristics with no apparent advantage of one abutment type over the other with regard to resistance to surface damage. Unfilled resin was found consistently to be the least damaging to abutment surfaces, although all scalers of all compositions caused detectable surface changes to polished surfaces of implant abutments.

Hydrology, nutrient concentrations, and nutrient yields in nearshore areas of four lakes in northern Wisconsin, 1999-2001

USGS Publications Warehouse

Graczyk, David J.; Hunt, Randall J.; Greb, Steven R.; Buchwald, Cheryl A.; Krohelski, James T.

2003-01-01

The effects of shoreline development on water quality and nutrient yields in nearshore areas of four lakes in northern Wisconsin were investigated from October 1999 through September 2001. The study measured surface runoff and ground-water flows from paired developed (sites containing lawn, rooftops, sidewalks, and driveways) and undeveloped (mature and immature woods) catchments adjacent to four lakes in northern Wisconsin. Water samples from surface runoff and ground water were collected and analyzed for nutrients. Coupled with water volumes, loads and subsequent yields of selected constituents were computed for developed and undeveloped catchments. The median runoff from lawn surfaces ranged from 0.0019 to 0.059 inch over the catchment area. Median surface runoff estimates from the wooded catchments were an order of magnitude less than those from the lawn catchments. The increased water volumes from the lawn catchments resulted in greater nutrient loads and subsequent annual nutrient yields from the developed sites. Soil temperature and soil moisture were measured at two sites with mixed lawn and wooded areas. At both of these sites, the area covered with a lawn commonly was warmer than the wooded area. No consistent differences in soil moisture were found. A ground-water model was constructed to simulate the local flow systems at two of the paired catchments. Model simulations showed that much of the ground water delivered to the lake originated from distant areas that did not contribute runoff directly to the lake. Surface runoff and ground-water nutrient concentrations from the lawn and wooded catchments did not have apparent patterns. Some of the median concentrations from lawns were significantly different (at the 0.05 significance level) from those at wooded catchments. Water wells and piezometers were sampled for chemical analyses three times during the study period. Variability in the shallow ground-water chemistry over time in the lawn samples was larger than samples from the wooded areas and upgradient wells. Median nutrient yields in surface runoff from lawns always were greater than those from the wooded catchments. Runoff volumes were the most important factor in determining whether lawns or wooded catchments contribute more nutrients to the lake. The ground-water system had appreciable nutrient concentrations, and are likely an important pathway for nutrient transport to the lake. The nitrate plus nitrite nitrogen and total phosphorus yields to the ground-water system from a lawn catchment were approximately 3 to 4 times greater than those from the wooded catchment. There was no difference in the yields of dissolved inorganic phosphorus to the ground-water system from the lawn and wooded catchments. Study results demonstrate that choosing the appropriate landscape position for locating lawns in sloped areas (specifically, slopes that do not terminate at the lake or areas with intervening flat or buffer zones between lawn and lake) can help reduce the adverse effect of lawns on the shallow ground water and, ultimately, the lake. Additional information would be needed to extrapolate these results to a large drainage area of a lake.

An interdisciplinary analysis of ERTS data for Colorado mountain environments using ADP Techniques

NASA Technical Reports Server (NTRS)

Hoffer, R. M. (Principal Investigator)

1972-01-01

Author identified significant preliminary results from the Ouachita portion of the Texoma frame of data indicate many potentials in the analysis and interpretation of ERTS data. It is believed that one of the more significant aspects of this analysis sequence has been the investigation of a technique to relate ERTS analysis and surface observation analysis. At present a sequence involving (1) preliminary analysis based solely upon the spectral characteristics of the data, followed by (2) a surface observation mission to obtain visual information and oblique photography to particular points of interest in the test site area, appears to provide an extremely efficient technique for obtaining particularly meaningful surface observation data. Following such a procedure permits concentration on particular points of interest in the entire ERTS frame and thereby makes the surface observation data obtained to be particularly significant and meaningful. The analysis of the Texoma frame has also been significant from the standpoint of demonstrating a fast turn around analysis capability. Additionally, the analysis has shown the potential accuracy and degree of complexity of features that can be identified and mapped using ERTS data.

Mercury Underpotential Deposition to Determine Iridium and Iridium Oxide Electrochemical Surface Areas

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

Alia, Shaun M.; Hurst, Katherine E.; Kocha, Shyam S.

Determining the surface areas of electrocatalysts is critical for separating the key properties of area-specific activity and electrochemical surface area from mass activity. Hydrogen underpotential deposition and carbon monoxide oxidation are typically used to evaluate iridium (Ir) surface areas, but are ineffective on oxides and can be sensitive to surface oxides formed on Ir metals. Mercury underpotential deposition is presented in this study as an alternative, able to produce reasonable surface areas on Ir and Ir oxide nanoparticles, and able to produce similar surface areas prior to and following characterization in oxygen evolution. Reliable electrochemical surface areas allow for comparativemore » studies of different catalyst types and the characterization of advanced oxygen evolution catalysts. Lastly, they also enable the study of catalyst degradation in durability testing, both areas of increasing importance within electrolysis and electrocatalysis.« less

Mercury Underpotential Deposition to Determine Iridium and Iridium Oxide Electrochemical Surface Areas

DOE PAGES

Alia, Shaun M.; Hurst, Katherine E.; Kocha, Shyam S.; ...

2016-06-02

Determining the surface areas of electrocatalysts is critical for separating the key properties of area-specific activity and electrochemical surface area from mass activity. Hydrogen underpotential deposition and carbon monoxide oxidation are typically used to evaluate iridium (Ir) surface areas, but are ineffective on oxides and can be sensitive to surface oxides formed on Ir metals. Mercury underpotential deposition is presented in this study as an alternative, able to produce reasonable surface areas on Ir and Ir oxide nanoparticles, and able to produce similar surface areas prior to and following characterization in oxygen evolution. Reliable electrochemical surface areas allow for comparativemore » studies of different catalyst types and the characterization of advanced oxygen evolution catalysts. Lastly, they also enable the study of catalyst degradation in durability testing, both areas of increasing importance within electrolysis and electrocatalysis.« less

Surface Texturing of Polyimide Composite by Micro-Ultrasonic Machining

NASA Astrophysics Data System (ADS)

Qu, N. S.; Zhang, T.; Chen, X. L.

2018-03-01

In this study, micro-dimples were prepared on a polyimide composite surface to obtain the dual benefits of polymer materials and surface texture. Micro-ultrasonic machining is employed for the first time for micro-dimple fabrication on polyimide composite surfaces. Surface textures of simple patterns were fabricated successfully with dimple depths of 150 μm, side lengths of 225-425 μm, and area ratios of 10-30%. The friction coefficient of the micro-dimple surfaces with side lengths of 325 or 425 μm could be increased by up to 100% of that of non-textured surfaces, alongside a significant enhancement of wear resistance. The results show that surface texturing of polyimide composite can be applied successfully to increase the friction coefficient and reduce wear, thereby contributing to a large output torque.

Analysis of pseudocolor transformations of ERTS-1 images of Southern California area. [geological faults and lineaments

NASA Technical Reports Server (NTRS)

Merifield, P. M. (Principal Investigator); Lamar, D. L.; Stratton, R. H.; Lamar, J. V.; Gazley, C., Jr.

1974-01-01

The author has identified the following significant results. Representative faults and lineaments, natural features on the Mojave Desert, and cultural features of the southern California area were studied on ERTS-1 images. The relative appearances of the features were compared on a band 4 and 5 subtraction image, its pseudocolor transformation, and pseudocolor images of bands 4, 5, and 7. Selected features were also evaluated in a test given students at the University of California, Los Angeles. Observations and the test revealed no significant improvement in the ability to detect and locate faults and lineaments on the pseudocolor transformations. With the exception of dry lake surfaces, no enhancement of the features studied was observed on the bands 4 and 5 subtraction images. Geologic and geographic features characterized by minor tonal differences on relatively flat surfaces were enhanced on some of the pseudocolor images.

A summary of selected early results from the ERTS-1 menhaden experiment

NASA Technical Reports Server (NTRS)

Stevenson, W. H. (Principal Investigator); Kemmerer, A. J.; Benigno, J. A.; Reese, G. B.; Minkler, F. C.

1973-01-01

The author has identified the following significant results. Imagery from ERTS-1 satellite was used in conjunction with aerial photographically-sensed menhaden distribution information, sea truth oceanographic measurements, and commercial fishing information from a 8685 square kilometer study area in the north-central portion of the Gulf of Mexico to demonstrate relationships between selected oceanographic parameters and menhaden distribution, ERTS-1 imagery and menhaden distribution, and ERTS-1 imagery and oceanographic parameters. ERTS-1, MSS band 5 imagery density levels correlated with photographically detected menhaden distribution patterns and could be explained based on sea truth Secchi disc transparency and water depth measurements. These two parameters, together with surface salinity, Forel-Ule color, and chlorophyll-a also were found to correlate significantly with menhaden distribution. Eight empirical models were developed which provided menhaden distribution predictions for the study area on combinations of Secchi disc transparency, water depth, surface salinity, and Forel-Ule color measurements.

Monitoring of Water-Level Fluctuation of Lake Nasser Using Altimetry Satellite Data

NASA Astrophysics Data System (ADS)

El-Shirbeny, Mohammed A.; Abutaleb, Khaled A.

2018-05-01

Apart from the Renaissance Dam and other constructed dams on the River Nile tributaries, Egypt is classified globally as a state of scarce water. Egypt's water resources are very limited and do not contribute a significant amount to its water share except the River Nile (55.5 billion m3/year). While the number of population increases every year, putting more stress on these limited resources. This study aims to use remote-sensing data to assess the change in surface area and water-level variation in Lake Nasser using remote-sensing data from Landsat-8 and altimetry data. In addition, it investigates the use of thermal data from Landsat-8 to calculate water loss based on evaporation from Lake Nasser. The eight Landsat-8 satellite images were used to study the change in surface area of Lake Nasser representing winter (January) and summer (June/July) seasons in two consecutive years (2015 and 2016). Time series analyses for 10-day temporal resolution water-level data from Jason-2/OSTM and Jason-3 altimetry was carried out to investigate water-level trends over the long term (1993 and 2016) and short term (2015-2016) in correspondence with the change of the surface area. Results indicated a shrink in the lake surface area in 2016 of approximately 14% compared to the 2015 area. In addition, the evaporation rate in the lake is very high causing a loss of approximately 20% of the total water share from the river Nile.

Calculating landscape surface area from digital elevation models

Treesearch

Jeff S. Jenness

2004-01-01

There are many reasons to want to know the true surface area of the landscape, especially in landscape analysis and studies of wildlife habitat. Surface area provides a better estimate of the land area available to an animal than planimetric area, and the ratio of this surface area to planimetric area provides a useful measure of topographic roughness of the landscape...

Geomorphic and landform survey of Northern Appennine Range (NAR)

NASA Technical Reports Server (NTRS)

Marino, C. M. (Principal Investigator); Zilioli, E.

1977-01-01

The author has identified the following significant results. An approach to landslide hazard detection was developed through the analysis of satellite imagery (LANDSAT 2) showing many landslide areas that occur on marine silts and clays in northern Appennine Range in Italy. A landslide risk score was given for large areas by narrowing and extending well defined areas, whose behavior and reflectivity variation was due to upper surface changes. Results show that this methodology allows evolution pattern of clay outflows to be distinguished.

Environmental Assessment Addressing the Defense Language Institute English Language Center (DLIELC), and the Inter-American Air Forces Academy (IAAFA) Area Development Plan at Lackland Air Force Base, Texas

DTIC Science & Technology

2012-01-01

Heat island” refers to built up areas that have hotter surface and air temperatures than nearby rural areas. Heat island effect occurs when...Summary of Environmental Effects The public and regulatory agency scoping process focused the analysis on the following environmental resources... effects of implementing the DLIELC and IAAFA ADP are not significant, that preparation of an Environmental Impact Statement is unnecessary, and that a

Linking playa surface dust emission potential to feedbacks between surface moisture and salt crust expansion through high resolution terrestrial laser scanning measurements

NASA Astrophysics Data System (ADS)

Nield, J. M.; King, J.; Wiggs, G.

2012-12-01

The dust emissivity of salt pans (or playas) can be significant but is controlled by interactions between wind erosivity, surface moisture, salt chemistry and crust morphology. These surface properties influence the aeolian transport threshold and can be highly variable over both short temporal and spatial scales. In the past, field studies have been hampered by practical difficulties in accurately measuring properties controlling sediment availability at the surface in high resolution. Studies typically therefore, have investigated large scale monthly or seasonal change using remote sensing and assume a homogeneous surface when predicting dust emissivity. Here we present the first high resolution measurements (sub-cm) of salt crust expansion related to changes in diurnal moisture over daily and weekly time periods using terrestrial laser scanning (TLS, ground-based LiDAR) on Sua Pan, Botswana. The TLS measures both elevation and relative surface moisture change simultaneously, without disturbing the surface. Measurement sequences enable the variability in aeolian sediment availability to be quantified along with temporal feedbacks associated with crust degradation. On crusts with well-developed polygon ridges (high aerodynamic and surface roughness), daily surface expansion was greater than 30mm. The greatest surface change occurred overnight on the upper, exposed sections of the ridges, particularly when surface temperatures dropping below 10°C. These areas also experienced the greatest moisture variation and became increasingly moist overnight in response to an increase in relative humidity. In contrast, during daylight hours, the ridge areas were drier than the lower lying inter-ridge areas. Positive feedbacks between surface topography and moisture reinforced the maximum diurnal moisture variation at ridge peaks, encouraging crust thrusting due to overnight salt hydration, further enhancing the surface, and therefore, aerodynamic roughness. These feedbacks between surface roughness and moisture have implications for dust emissivity because crust expansion increases fluff production which is one of the main dust source materials. Further, increased roughness can locally increase wind erosivity and the potential evaporation of ridge areas. Crust thrusting also weakens the ridge peaks, developing cracked surfaces and exposing the sediment supply source below. These fast acting processes can have a major influence on wind erosion variability and dust emissivity from key dust source regions.; a-d) Elevation change overnight. e-f) Elevation change over 6 days.

Characteristics of Surface Urban Heat Island (SUHI) over the Gangetic Plain of Bihar, India

NASA Astrophysics Data System (ADS)

Barat, Archisman; Kumar, Sunny; Kumar, Praveen; Parth Sarthi, P.

2018-05-01

The rapid urbanisation impacts on environment, climate, agriculture, water resources trigger several problems to human beings. The present study is carried out to estimate intensity and trend of Urban Heat Island (UHI) as Surface UHI (SUHI) over towns/cities of the Gangetic plain of the state of Bihar, India, in which urban areas show relatively greater Land Surface Temperature (LST) than its rural surroundings especially during night times. The LST data (2001-14) of Moderate Resolution Imaging Spectroradiometer (MODIS) is used for five major towns/cities of Bihar namely, Bhagalpur, Gaya, Patna, Purnea and Muzzaffarpur. Each city is classified into Urban, Suburban and Rural zones as per land cover of the area. During winter months (January, February, November and December), UHI is more intense over all towns/cities. Mann-Kendall Test is applied on Surface Urban Heat Island Intensity (SUHII) in which MK-Test Statistic (S) shows a significant increasing trend. This trend would alarm a risk to increase in air pollution, heat related biohazards, energy demand in the region. This study shows the need of urban greening and proper town planning over the considered areas to mitigate the changes.

Sulfur-carbon nanocomposite cathodes improved by an amphiphilic block copolymer for high-rate lithium-sulfur batteries.

PubMed

Fu, Yongzhu; Su, Yu-Sheng; Manthiram, Arumugam

2012-11-01

A sulfur-carbon nanocomposite consisting of a commercial high-surface-area carbon (i.e., Black Pearls 2000, BET surface area >1000 m² g⁻¹) and sulfur has been synthesized by an in situ deposition method. The nanocomposite is in the form of agglomerated nanoparticles, with the micropores within the carbon filled with sulfur and the mesopores on the carbon surface almost completely covered by sulfur. The BET surface area of the nanocomposite containing a sulfur content of 63.5 wt % is significantly reduced to only 40 m² g⁻¹. Cathodes containing the nanocomposite and Pluronic F-127 block copolymer, which partially replaces the polyvinylidene fluoride binder, were prepared and evaluated in lithium cells by cyclic voltammetry and galvanostatic cycling. The nanocomposite cathodes with the copolymer show improved electrochemical stability and cyclability. The Pluronic copolymer helps retain a uniform nanocomposite structure within the electrodes, improving the electrochemical contact, which was manifested by scanning electron microscopy and electrochemical impedance spectroscopy. The sulfur-Black Pearls nanocomposite with the Pluronic copolymer as an additive in the electrodes is promising for high-rate rechargeable lithium-sulfur batteries.

Dental caries, its surface susceptibility and dental fluorosis in South India.

PubMed

Acharya, Shashidhar

2005-12-01

To correlate water fluoride levels with dental caries and dental fluorosis in areas with different levels of fluoride in the drinking water and to establish the surface susceptibility of dental caries in an endemic fluoride area. 544 schoolchildren 12 to 15 years of age from the Davangere region of India were examined. The DMFS index was used to measure dental caries, which was further differentiated into smooth surface and pit and fissure lesions. Dean's index was used to diagnose dental fluorosis. Five villages with fluoride levels ranging from 0.43 ppm to 3.41 ppm were studied. There was a highly significant negative correlation (r = -0.16) between water fluoride levels and dental caries. Dental fluorosis increased from 16% at 0.43 ppm to 100% at 3.41 ppm. Pit and fissure lesions made up the vast majority of the lesions in all the villages and showed a decreasing trend with increasing fluoride levels, however no such trend was seen for smooth surface lesions. Water fluoride was an important factor responsible for the low caries prevalence. The prevalence of fluorosis and low caries even in low fluoride areas may point to a halo effect.

Large-scale structural alteration of brain in epileptic children with SCN1A mutation.

PubMed

Lee, Yun-Jeong; Yum, Mi-Sun; Kim, Min-Jee; Shim, Woo-Hyun; Yoon, Hee Mang; Yoo, Il Han; Lee, Jiwon; Lim, Byung Chan; Kim, Ki Joong; Ko, Tae-Sung

2017-01-01

Mutations in SCN1A gene encoding the alpha 1 subunit of the voltage gated sodium channel are associated with several epilepsy syndromes including genetic epilepsy with febrile seizures plus (GEFS +) and severe myoclonic epilepsy of infancy (SMEI). However, in most patients with SCN1A mutation, brain imaging has reported normal or non-specific findings including cerebral or cerebellar atrophy. The aim of this study was to investigate differences in brain morphometry in epileptic children with SCN1A mutation compared to healthy control subjects. We obtained cortical morphology (thickness, and surface area) and brain volume (global, subcortical, and regional) measurements using FreeSurfer (version 5.3.0, https://surfer.nmr.mgh.harvard.edu) and compared measurements of children with epilepsy and SCN1A gene mutation ( n  = 21) with those of age and gender matched healthy controls ( n  = 42). Compared to the healthy control group, children with epilepsy and SCN1A gene mutation exhibited smaller total brain, total gray matter and white matter, cerebellar white matter, and subcortical volumes, as well as mean surface area and mean cortical thickness. A regional analysis revealed significantly reduced gray matter volume in the patient group in the bilateral inferior parietal, left lateral orbitofrontal, left precentral, right postcentral, right isthmus cingulate, right middle temporal area with smaller surface area and white matter volume in some of these areas. However, the regional cortical thickness was not significantly different in two groups. This study showed large-scale developmental brain changes in patients with epilepsy and SCN1A gene mutation, which may be associated with the core symptoms of the patients. Further longitudinal MRI studies with larger cohorts are required to confirm the effect of SCN1A gene mutation on structural brain development.

Surface-water characteristics and quality on the Osage Reservation, Osage County, Oklahoma, 1999

USGS Publications Warehouse

Abbott, Marvin M.; Tortorelli, Robert L.

2002-01-01

Concern about the effects of early oil-industry practices of surface disposal of produced-brine water prompted an investigation of the surface-water quality on the Osage Reservation. About 38,600 oil wells have been drilled on the Osage Reservation since drilling began in 1896. The Osage Reservation comprises three major drainage basins. The Caney River Basin is in the northeast, the Bird Creek Basin is in the southeast, and the Salt Creek Basin in the west. Variations in streamflow on the Osage Reservation during a year primarily result from variations in the quantity and frequency of rainfall, evapotranspiration, and reservoir operations. Most streams do not flow during low rainfall periods in late summer, early fall, and in winter. Percent of mean annual discharge is largest during March through June, averaging 54 to 62 percent and smallest during December, January, July, and August, averaging only 14 to 21 percent. The basin areas of Caney River in the reservation (251 square miles), Salt Creek (273 square miles), and Sand Creek (227 square miles) are about the same and the basin areas of the Bird Creek Basin (418 square miles) and Homily Creek Basin (383 square miles) are similar in area. One hundred forty surface-water sites were sampled once during either February, March or August 1999. The surface-drainage areas, incremental basins, between sample sites along a stream, range in size from 0.26 to 123 square miles with a median of 8.6 square miles. Total number of oil wells upgradient of the samples sites is 31,432 or 80 percent of the total in the reservation. The total number of oil wells in the Caney River Basin in the reservation (2,975 wells), Salt Creek Basin (4,619 wells), and Sand Creek Basin (3,858 wells) are about the same and the total number of oil wells in the Bird Creek Basin (8,858 wells) and Hominy Creek Basin (7,842 wells) are similar. The number of oil wells per square mile in the incremental basins ranges for 0.86 to 154. Surface-water quality monitoring had been conducted previously at two sites included in this study. Dissolved chloride concentrations for the two samples collected during 1999 were equaled or exceeded at both sites by the historical data. There is no statistically significant difference between the distribution of the dissolved chloride concentrations from the surface water and nearby ground-water samples. The surface-water quality samples had significantly lesser concentrations of dissolved solids, sulfate, and nitrite plus nitrate as nitrogen than the ground-water samples. Chloride yield, reported in tons per day per square mile, is the chloride load divided by the basin area upstream of the sample site. The mean of the chloride yields for all the samples was 0.07 ton per day per square mile. Many sample locations where yields were greater than 0.07 ton per day per square mile were areas where dissolved chloride concentrations from surface-water samples were greater than 250 milligrams per liter in an earlier water-quality investigation. An investigation of possible relations between the surface-water quality data and the oil-well construction data for the incremental basins and for 1-mile radial distance upstream in the incremental basins was conducted. The oil-well data also were grouped by the time periods of activity into pre-1930, 1930 to 1970, and post-1970. These groups attempt to account for differences in industry drilling and producing practices associated with various periods. No statistically significant correlations were found between the surface-water quality data and the oil-well construction data.

Snags and Down Wood on Upland Oak Sites in the Missouri Ozark Forest Ecosystem Project

Treesearch

Stephen R. Shifley; Brian L. Brookshire; David R. Larsen; Laura A. Herbeck; Randy G. Jensen

1997-01-01

We analyzed volume, surface area, and percent cover of down wood to determine if there were pre-treatment differences among the sites in the Missouri Ozark Forest Ecosystem Project. We also compared pre-treatment values for the number and basal area of snags. We observed no statistically significant differences (P > 0.05) among treatment classes for these...

Shaping ability of single-file reciprocating and heat-treated multifile rotary systems: a micro-CT study.

PubMed

Marceliano-Alves, M F V; Sousa-Neto, M D; Fidel, S R; Steier, L; Robinson, J P; Pécora, J D; Versiani, M A

2015-12-01

To investigate changes in three-dimensional geometry, in various cross-sectional morphological parameters and in the centring ability of root canals prepared with different preparation systems using microcomputed tomographic imaging technology. Sixty-four mesial canals of mandibular molars were matched based on similar morphological dimensions using micro-CT evaluation and assigned to four experimental groups (n = 16), according to the canal preparation technique: Reciproc, WaveOne, Twisted File and HyFlex CM systems. Changes in several 2D (area, perimeter, form factor, roundness, minor and major diameter) and 3D [volume, surface area, structure model index (SMI)] morphological parameters, as well as canal transportation, were compared with preoperative values using Kruskal-Wallis and anovapost hoc Tukey's tests with the significance level set at 5%. Preparation significantly increased all tested parameters in the experimental groups. No significant differences were observed between groups regarding changes in volume, surface area, SMI, form factor and roundness of the root canal after preparation (P > 0.05). In the apical third, the Reciproc group had significantly greater changes in canal area, perimeter, major and minor diameters than the other groups (P < 0.05). Overall, the Twisted File and HyFlex CM systems were associated with significantly less transportation than the reciprocating instruments, Reciproc and WaveOne (P < 0.05). Shaping procedures led to the enlargement of the root canal space with no evidence of significant preparation errors. Changes in 3D parameters were not different between groups whilst, in the apical third, Reciproc was associated with significantly greater changes in several 2D parameters compared to the other groups. Twisted File and HyFlex CM systems were able to maintain the original canal anatomy with less canal transportation than Reciproc and WaveOne; however, these differences are unlikely to be of clinical significance. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Changes in Land Use Intensity Within the Don and Dnieper River Basins Following the Collapse of the Soviet Union as Revealed by Spatio-temporal Trend Analysis

NASA Astrophysics Data System (ADS)

Kovalskyy, V.; Henebry, G.

2007-12-01

We analyzed changes in trends of land surface phenology (LSP) within two major river basins in Western Eurasia. The basins of Don and Dnieper Rivers extend over 862,000 ha and include 17% of the impounded water surface area in the former Soviet Union. Major changes in agricultural practices occurring after 1991 led to some time drastic reductions in the cultivated area receiving fertilizers and the amount of water consumed for irrigation in addition to other macro-indicators of agricultural sector land use intensity. Image time series analysis can localize the extent, direction, and intensity of changes during the 1990s. Using vegetation index data from the AVHRR PAL and GIMMS datasets from 1982-1988 (Soviet period) and 1995-2000 (post-Soviet period) coupled with contemporary land cover maps from MODIS, we identified the spatial extent of temporal trends and assess their significance using seasonal Mann-Kendall tests adjusted for first-order autocorrelation. Roughly 90% of croplands and forested land in Dnieper Basin exhibited no significant trends during the Soviet period. The Don Basin had more significant positive trends during the Soviet period than the Dnieper Basin. There was a substantial disagreement between datasets on the extent of significant positive trends in Don croplands (35% for GIMMS vs. 8% for PAL) and in Don forests during Soviet period (38% for GIMMS vs. 27% for PAL). Although very little area in either basins showed significant negative trends during the Soviet period, substantial areas fell under significant negative trends during the post-Soviet period. We also found major disagreement on extent of significant negative trends in Don forests during post-Soviet period (6% for GIMMS vs. 24% for PAL). Even though, there are some significant disagreements between the datasets, there is no evidence of a consistent bias in the change analysis. Changes in irrigation water use may account for some of the changes in trend direction.

Evaluation of Advanced Reactive Surface Area Estimates for Improved Prediction of Mineral Reaction Rates in Porous Media

NASA Astrophysics Data System (ADS)

Beckingham, L. E.; Mitnick, E. H.; Zhang, S.; Voltolini, M.; Yang, L.; Steefel, C. I.; Swift, A.; Cole, D. R.; Sheets, J.; Kneafsey, T. J.; Landrot, G.; Anovitz, L. M.; Mito, S.; Xue, Z.; Ajo Franklin, J. B.; DePaolo, D.

2015-12-01

CO2 sequestration in deep sedimentary formations is a promising means of reducing atmospheric CO2 emissions but the rate and extent of mineral trapping remains difficult to predict. Reactive transport models provide predictions of mineral trapping based on laboratory mineral reaction rates, which have been shown to have large discrepancies with field rates. This, in part, may be due to poor quantification of mineral reactive surface area in natural porous media. Common estimates of mineral reactive surface area are ad hoc and typically based on grain size, adjusted several orders of magnitude to account for surface roughness and reactivity. This results in orders of magnitude discrepancies in estimated surface areas that directly translate into orders of magnitude discrepancies in model predictions. Additionally, natural systems can be highly heterogeneous and contain abundant nano- and micro-porosity, which can limit connected porosity and access to mineral surfaces. In this study, mineral-specific accessible surface areas are computed for a sample from the reservoir formation at the Nagaoka pilot CO2 injection site (Japan). Accessible mineral surface areas are determined from a multi-scale image analysis including X-ray microCT, SEM QEMSCAN, XRD, SANS, and SEM-FIB. Powder and flow-through column laboratory experiments are performed and the evolution of solutes in the aqueous phase is tracked. Continuum-scale reactive transport models are used to evaluate the impact of reactive surface area on predictions of experimental reaction rates. Evaluated reactive surface areas include geometric and specific surface areas (eg. BET) in addition to their reactive-site weighted counterparts. The most accurate predictions of observed powder mineral dissolution rates were obtained through use of grain-size specific surface areas computed from a BET-based correlation. Effectively, this surface area reflects the grain-fluid contact area, or accessible surface area, in the powder dissolution experiment. In the model of the flow-through column experiment, the accessible mineral surface area, computed from the multi-scale image analysis, is evaluated in addition to the traditional surface area estimates.

Distribution of pesticides in dust particles in urban environments.

PubMed

Richards, Jaben; Reif, Ruben; Luo, Yuzhuo; Gan, Jay

2016-07-01

In regions with a mild climate, pesticides are often used around homes for pest control. Recent monitoring studies have linked pesticide use in residential areas to aquatic toxicity in urban surface water ecosystems, and suggested dust particles on paved surfaces as an important source of pesticides. To test the hypothesis that dust on hard surfaces is a significant source of pesticides, we evaluated spatial and temporal patterns of current-use insecticides in Southern California, and further explored their distribution as a function of particle sizes. Pyrethroid insecticides were detected in dust from the driveway, curb gutter and street at 53.5-94.8%, with median concentrations of 1-46 ng g(-1). Pyrethroid residues were uniformly distributed in areas adjacent to a house, suggesting significant redistribution. The total levels of pyrethroids in dust significantly (p < 0.01) decreased from October to February, suggesting rainfalls as a major mechanism to move pesticide residues offsite. Fipronil as well as its degradation products, were detected at 50.6-75.5%, and spatial and temporal patterns of fipronil residues suggested rapid transformations of fipronil to its biologically active intermediates. Moreover, pyrethroids were found to be enriched in fine particles that have a higher mobility in runoff than coarse particles. Results from this study highlight the widespread occurrence of pesticides in outdoor dust around homes and the potential contribution to downstream surface water contamination via rain-induced runoff. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of oxygen plasma treatment on the electrochemical performance of the rayon and polyacrylonitrile based carbon felt for the vanadium redox flow battery application

NASA Astrophysics Data System (ADS)

Dixon, D.; Babu, D. J.; Langner, J.; Bruns, M.; Pfaffmann, L.; Bhaskar, A.; Schneider, J. J.; Scheiba, F.; Ehrenberg, H.

2016-11-01

Oxygen plasma treatment was applied on commercially available graphite felt electrodes based on rayon (GFA) and polyacrylonitrile (GFD). The formation of functional groups on the surface of the felt was confirmed by X-ray photoelectron spectroscopy measurements. The BET studies of the plasma treated electrodes showed no significant increase in surface area for both the rayon as well as the PAN based felts. Both plasma treated electrodes showed significantly enhanced V3+/V2+ redox activity compared to the pristine electrodes. Since an increase of the surface area has been ruled out for plasma treated electrode the enhanced activity could be attributed to surface functional groups. Interestingly, plasma treated GFD felts showed less electrochemical activity towards V5+/V4+ compared to the pristine electrode. Nevertheless, an overall increase of the single cell performance was still observed as the negative electrode is known to be the performance limiting electrode. Thus, to a great extent the present work helps to preferentially understand the importance of functional groups on the electrochemical activity of negative and positive redox reaction. The study emphasizes the need of highly active electrodes especially at the negative electrode side as inactive electrodes can still facilitate hydrogen evolution and degrade the electrolyte in VRFBs.

Earth resources evaluation for New Mexico by LANDSAT-2

NASA Technical Reports Server (NTRS)

Vonderlinden, K. (Principal Investigator); Feldman, S. C.; Inglis, M. H.; Tabet, D.; Kottlowski, F. E.

1975-01-01

The author has identified the following significant results. A cost effective technique is considered for measuring and monitoring surface area fluctuations in lake size in southeastern New Mexico over a two year period. The lakes are shallow, and therefore a small volume increase results in a noticeable increase in surface area on the LANDSAT imagery. Lake sizes are measured on an I(2)S Digicol viewer. Water from potash mining operations is being pumped into some of these lakes and the input volume is documented. Using water input and surface contour as well as direct lake level measurements as ground truth as well as the LANDSAT images, calculations may be possible regarding how much additional industrial water can be added to these lakes without the occurrence of saline see page into the major river system.

Exploration for fractured petroleum reservoirs using radar/Landsat merge combinations

NASA Technical Reports Server (NTRS)

Macdonald, H.; Waite, W.; Borengasser, M.; Tolman, D.; Elachi, C.

1981-01-01

Since fractures are commonly propagated upward and reflected at the earth's surface as subtle linears, detection of these surface features is extremely important in many phases of petroleum exploration and development. To document the usefulness of microwave analysis for petroleum exploration, the Arkansas part of the Arkoma basin is selected as a prime test site. The research plan involves comparing the aircraft microwave imagery and Landsat imagery in an area where significant subsurface borehole geophysical data are available. In the northern Arkoma basin, a positive correlation between the number of linears in a given area and production from cherty carbonate strata is found. In the southern part of the basin, little relationship is discernible between surface structure and gas production, and no correlation is found between gas productivity and linear proximity or linear density as determined from remote sensor data.

Innovative approach to retrieve land surface emissivity and land surface temperature in areas of highly dynamic emissivity changes by using thermal infrared data

NASA Astrophysics Data System (ADS)

Heinemann, S.

2015-12-01

The land surface temperature (LST) is an extremely significant parameter in order to understand the processes of energetic interactions between Earth's surface and atmosphere. This knowledge is significant for various environmental research questions, particularly with regard to the recent climate change. This study shows an innovative approach to retrieve land surface emissivity (LSE) and LST by using thermal infrared (TIR) data from satellite sensors, such as SEVIRI and AATSR. So far there are no methods to derive LSE/LST particularly in areas of highly dynamic emissivity changes. Therefore especially for regions with large surface temperature amplitude in the diurnal cycle such as bare and uneven soil surfaces but also for regions with seasonal changes in vegetation cover including various surface areas such as grassland, mixed forests or agricultural land different methods were investigated to identify the most appropriate one. The LSE is retrieved by using the day/night Temperature-Independent Spectral Indices (TISI) method, and the Generalised Split-Window (GSW) method is used to retrieve the LST. Nevertheless different GSW algorithms show that equal LSEs lead to large LST differences. Additionally LSE is also measured using a NDVI-based threshold method (NDVITHM) to distinguish between soil, dense vegetation cover and pixel composed of soil and vegetation. The data used for this analysis were derived from MODIS TIR. The analysis is implemented with IDL and an intercomparison is performed to determine the most effective methods. To compensate temperature differences between derived and ground truth data appropriate correction terms by comparing derived LSE/LST data with ground-based measurements are developed. One way to calibrate LST retrievals is by comparing the canopy leaf temperature of conifers derived from TIR data with the surrounding air temperature (e.g. from synoptic stations). Prospectively, the derived LSE/LST data become validated with near infrared data obtained from an UVA with a TIR camera (TIRC) onboard, and also compared with ground-based measurements. This study aims to generate an appropriate method by integrating developed correction terms to eventually obtain a high correlation between all, LSE/LST, TIRC and ground truth data.

Dynamic factor modeling of ground and surface water levels in an agricultural area adjacent to Everglades National Park

NASA Astrophysics Data System (ADS)

Ritter, A.; Muñoz-Carpena, R.

2006-02-01

The extensive eastern boundary of Everglades National Park (ENP) in south Florida (USA) is subject to one the most expensive and ambitious environmental restoration projects in history. Understanding and predicting the interaction between the shallow aquifer and surface water is a key component for fine-tuning the process. The Frog Pond is an intensively instrumented agricultural 2023 ha area adjacent to ENP. The interactions among 21 multivariate daily time series (ground and surface water elevations, rainfall and evapotranspiration) available from this area were studied by means of dynamic factor analysis, a novel technique in the field of hydrology. This method is designed to determine latent or background effects governing variability or fluctuations in non-stationary time series. Water levels in 16 wells and two drainage ditch locations inside the area were selected as response variables, and canal levels and net recharge as explanatory variables. Elevations in the two canals delimiting the Frog Pond area were found to be the main factors explaining the response variables. This influence of canal elevations on water levels inside the area was complementary and inversely related to the distance between the observation point and each canal. Rainfall events do not affect daily water levels significantly but are responsible for instantaneous or localized groundwater responses that in some cases can be directly associated with the risk of flooding. This close coupling between surface and groundwater levels, that corroborates that found by other authors using different methods, could hinder on-going environmental restoration efforts in the area by bypassing the function of wetlands and other surface features. An empirical model with a reduced set of parameters was successfully developed and validated in the area by interpolating the results from the dynamic factor analysis across the spatial domain (coefficient of efficiency across the domain: 0.66-0.99). Although specific to the area, the resulting model is deemed useful for water management within the wide range of conditions similar to those present during the experimental period.

Simulation of boreal Summer Monsoon Rainfall using CFSV2_SSiB model: sensitivity to Land Use Land Cover (LULC)

NASA Astrophysics Data System (ADS)

Chilukoti, N.; Xue, Y.

2016-12-01

The land surface play a vital role in determining the surface energy budget, accurate representation of land use and land cover (LULC) is necessary to improve forecast. In this study, we have investigated the influence of surface vegetation maps with different LULC on simulating the boreal summer monsoon rainfall. Using a National Centres for Environmental Prediction (NCEP) Coupled Forecast System version 2(CFSv2) model coupled with Simplified Simple Biosphere (SSiB) model, two experiments were conducted: one with old vegetation map and one with new vegetation map. The significant differences between new and old vegetation map were in semi-arid and arid areas. For example, in old map Tibetan plateau classified as desert, which is not appropriate, while in new map it was classified as grasslands or shrubs with bare soil. Old map classified the Sahara desert as a bare soil and shrubs with bare soil, whereas in new map it was classified as bare ground. In addition to central Asia and the Sahara desert, in new vegetation map, Europe had more cropped area and India's vegetation cover was changed from crops and forests to wooded grassland and small areas of grassland and shrubs. The simulated surface air temperature with new map shows a significant improvement over Asia, South Africa, and northern America by some 1 to 2ºC and 2 to 3ºC over north east China and these are consistent with the reduced rainfall biases over Africa, near Somali coast, north east India, Bangladesh, east China sea, eastern Pacific and northern USA. Over Indian continent and bay of Bengal dry rainfall anomalies that is the only area showing large dry rainfall bias, however, they were unchanged with new map simulation. Overall the CFSv2(coupled with SSiB) model with new vegetation map show a promising result in improving the monsoon forecast by improving the Land -Atmosphere interactions. To compare with the LULC forcing, experiment was conducted using the Global Forecast System (GFS) simulations forced with different observed Sea Surface Temperatures (SST) for the same period: one is from NCEP reanalysis and one from Hadley Center. They have substantial difference in Indian Ocean. Preliminary analysis shows that, the impact of these two SST data sets on Indian summer monsoon rainfall has no significant impact.

Correlative bacteriologic and micro-computed tomographic analysis of mandibular molar mesial canals prepared by self-adjusting file, reciproc, and twisted file systems.

PubMed

Siqueira, José F; Alves, Flávio R F; Versiani, Marco A; Rôças, Isabela N; Almeida, Bernardo M; Neves, Mônica A S; Sousa-Neto, Manoel D

2013-08-01

This ex vivo study evaluated the disinfecting and shaping ability of 3 protocols used in the preparation of mesial root canals of mandibular molars by means of correlative bacteriologic and micro-computed tomographic (μμCT) analysis. The mesial canals of extracted mandibular molars were contaminated with Enterococcus faecalis for 30 days and assigned to 3 groups based on their anatomic configuration as determined by μCT analysis according to the preparation technique (Self-Adjusting File [ReDent-Nova, Ra'anana, Israel], Reciproc [VDW, Munich, Germany], and Twisted File [SybronEndo, Orange, CA]). In all groups, 2.5% NaOCl was the irrigant. Canal samples were taken before (S1) and after instrumentation (S2), and bacterial quantification was performed using culture. Next, mesial roots were subjected to additional μCT analysis in order to evaluate shaping of the canals. All instrumentation protocols promoted a highly significant intracanal bacterial reduction (P < .001). Intergroup quantitative and qualitative comparisons disclosed no significant differences between groups (P > .05). As for shaping, no statistical difference was observed between the techniques regarding the mean percentage of volume increase, the surface area increase, the unprepared surface area, and the relative unprepared surface area (P > .05). Correlative analysis showed no statistically significant relationship between bacterial reduction and the mean percentage increase of the analyzed parameters (P > .05). The 3 instrumentation systems have similar disinfecting and shaping performance in the preparation of mesial canals of mandibular molars. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Serum titanium, niobium and aluminium levels two years following instrumented spinal fusion in children: does implant surface area predict serum metal ion levels?

PubMed

Cundy, Thomas P; Cundy, William J; Antoniou, Georgia; Sutherland, Leanne M; Freeman, Brian J C; Cundy, Peter J

2014-11-01

Measurement of serum metal ion levels is used to determine systemic exposure to implant-derived metal debris that may be generated by processes of wear and corrosion. The aim of this study is to investigate predictors of serum metal ion levels in children undergoing instrumented spinal arthrodesis using a titanium alloy, focusing on implant characteristics and instrumentation construct design variables. This prospective longitudinal cohort study involved 33 children. Serum samples were obtained preoperatively:and at five defined interval periods over the first:two post-operative years. Samples were analysed using high resolution:inductively coupled plasma mass spectrometry to measure titanium, niobium and aluminium concentrations. Instrumentation characteristics were catalogued and construct surface area (SA) measurements calculated using an implant-specific software algorithm tool. Significantly elevated levels of serum titanium and niobium were observed (p< 0.0001), with >95 % of post-operative levels abnormally elevated. Significant predictors of serum titanium and niobium levels included time since surgery, surgical procedure (posterior or anterior fusion), number of levels fused, number of pedicle screws inserted, total rod length, total metal SA, total exposed metal SA and total metal-on-metal SA. All significant instrumentation variables were highly correlated. There is a strong relationship between implant SA and both serum titanium and niobium levels. The direct clinical implications of these findings for patients are uncertain, but remain of concern. Surgeons should be aware of the strong correlation between implant surface area of the chosen construct and the subsequent serum metal ion levels.

Modeling evapotranspiration over China's landmass from 1979-2012 using three surface models

NASA Astrophysics Data System (ADS)

Sun, Shaobo; Chen, Baozhang; Zhang, Huifang; Lin, Xiaofeng

2017-04-01

Land surface models (LSMs) are useful tools to estimate land evapotranspiration at a grid scale and for a long-term applications. Here, the Community Land Model 4.0 (CLM4.0), Dynamic Land Model (DLM) and Variable Infiltration Capacity (VIC) model were driven with observation-based forcing data sets, and a multiple LSM ensemble-averaged evapotranspiration (ET) product (LSMs-ET) was developed and its spatial-temporal variations were analyzed for the China landmass over the period 1979-2012. Evaluations against measurements from nine flux towers at site scale and surface water budget based ET at regional scale showed that the LSMs-ET had good performance in most areas of China's landmass. The inter-comparisons between the ET estimates and the independent ET products from remote sensing and upscaling methods suggested that there were a fairly consistent patterns between each data sets. The LSMs-ET produced a mean annual ET of 351.24±10.7 mm yr-1 over 1979-2012, and its spatial-temporal variation analyses showed that (i) there was an overall significant ET increasing trend, with a value of 0.72 mm yr-1 (p < 0.01); (ii) 36.01% of Chinese land had significant increasing trends, ranging from 1 to 9 mm yr-1, while only 6.41% of the area showed significant decreasing trends, ranging from -6.28 to -0.08 mm yr-1. Analyses of ET variations in each climate region clearly showed that the Tibetan Plateau areas were the main contributors to the overall increasing ET trends of China.

Surface temperature statistics over Los Angeles - The influence of land use

NASA Technical Reports Server (NTRS)

Dousset, Benedicte

1991-01-01

Surface temperature statistics from 84 NOAA AVHRR (Advanced Very High Resolution Radiometer) satellite images of the Los Angeles basin are interpreted as functions of the corresponding urban land-cover classified from a multispectral SPOT image. Urban heat islands observed in the temperature statistics correlate well with the distribution of industrial and fully built areas. Small cool islands coincide with highly watered parks and golf courses. There is a significant negative correlation between the afternoon surface temperature and a vegetation index computed from the SPOT image.

Development of unbonded and bonded areas in relation to Populus species wood characteristics in grinding

Treesearch

L.K. Lehtonen; J.H. Lehto; A.W. Rudie

2004-01-01

In terms of fibre development in mechanical pulping, most of the energy is spent on the creation of specific surface area. The total surface area created can be divided into two categories: surface area that adds to the unbonded area (optical properties) and surface area that adds to the bonded area (strength properties) of mechanical papers. This paper considers these...

Wear resistance of a modified polymethyl methacrylate artificial tooth compared to five commercially available artificial tooth materials.

PubMed

Kamonwanon, Pranithida; Yodmongkol, Sirasa; Chantarachindawong, Rojcharin; Thaweeboon, Sroisiri; Thaweeboon, Boonyanit; Srikhirin, Toemsak

2015-08-01

Wear resistance is a limitation of artificial denture teeth. Improving the wear resistance of conventional artificial denture teeth is of value to prosthodontic patients. The purpose of this in vitro study was to evaluate the wear resistance and hardness of modified polymethyl methacrylate artificial denture teeth compared to 5 commercially available artificial tooth materials. This study evaluated 180 artificial denture teeth (6 groups) that included 3 groups of conventional artificial teeth (MajorDent, Cosmo HXL, and Gnathostar), 2 groups of composite resin artificial teeth (Endura and SR Orthosit PE), and 1 group of modified surface artificial teeth. The flattened buccal surface of each tooth (n=15) was prepared for investigation with the Vickers hardness test and the elucidate wear test (n=15) by using a brushing machine. Each group was loaded for 18,000 cycles, at 2 N, and 150 rpm. The wear value was identified with a profilometer. The data were statistically analyzed by using 1-way ANOVA and post hoc Turkey honestly significant difference tests (α=.001). The tribologies were observed under a scanning electron microscope, and the cytotoxicities were evaluated by MTT assay. The Vickers hardnesses ranged from 28.48 to 39.36. The wear depths and worn surface area values ranged from 1.12 to 10.79 μm and from 6.74 to 161.95 μm(2). The data revealed that the modified artificial denture teeth were significantly harder and exhibited significantly higher wear resistance than did the conventional artificial teeth (P<.001). The scanning electron microscopic images revealed cross sections of the conventional artificial denture teeth with intensively worn surface areas after brushing. The cytotoxicity test revealed 97.85% cell viability, which indicates the nontoxicity of the modified surface of this material. Within the limitations of this study, the polymethyl methacrylate modified surface artificial denture teeth was not significantly different from that of the composite resin artificial denture teeth, with the exceptions that the surface was harder and more wear resistant. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Selenium in irrigated agricultural areas of the western United States

USGS Publications Warehouse

Nolan, B.T.; Clark, M.L.

1997-01-01

A logistic regression model was developed to predict the likelihood that Se exceeds the USEPA chronic criterion for aquatic life (5 ??g/L) in irrigated agricultural areas of the western USA. Preliminary analysis of explanatory variables used in the model indicated that surface-water Se concentration increased with increasing dissolved solids (DS) concentration and with the presence of Upper Cretaceous, mainly marine sediment. The presence or absence of Cretaceous sediment was the major variable affecting Se concentration in surface-water samples from the National Irrigation Water Quality Program. Median Se concentration was 14 ??g/L in samples from areas underlain by Cretaceous sediments and < 1 ??g/L in samples from areas underlain by non-Cretaceous sediments. Wilcoxon rank sum tests indicated that elevated Se concentrations in samples from areas with Cretaceous sediments, irrigated areas, and from closed lakes and ponds were statistically significant. Spearman correlations indicated that Se was positively correlated with a binary geology variable (0.64) and DS (0.45). Logistic regression models indicated that the concentration of Se in surface water was almost certain to exceed the Environmental Protection Agency aquatic-life chronic criterion of 5 ??g/L when DS was greater than 3000 mg/L in areas with Cretaceous sediments. The 'best' logistic regression model correctly predicted Se exceedances and nonexceedances 84.4% of the time, and model sensitivity was 80.7%. A regional map of Cretaceous sediment showed the location of potential problem areas. The map and logistic regression model are tools that can be used to determine the potential for Se contamination of irrigated agricultural areas in the western USA.

Application of ERTS-1-data to the protection and management of New Jersey's coastal environment

NASA Technical Reports Server (NTRS)

Yunghans, R. S.; Feinberg, E. B.; Mairs, R. L. (Principal Investigator); Woodward, D.; Thibault, D. A.; Macomber, R. T.

1973-01-01

The author has identified the following significant results. New Jersey's planned, regionalized network of sewage disposal facilities has been plotted on an ERTS-1 mosaic and circulation parameters for each of the planned outfall locations have been analyzed using the ERTS-1 imagery and comparative aircraft photography. Work is continuing on the circulation and dispersion of barge-dumped wastes in the New York Bight area. One of the largest remote sensing experiments ever attempted in this country was completed on April 7, 1973 during the ERTS-1 overpass. The test area included the northern portion of New Jersey and the Raritan Bay - New York Harbor area. Three NASA aircraft, two helicopters, nine surface vessels, 40 ground team personnel, and numerous oceanographic, radiometric, and meteorological equipment were deployed in an effort to characterize the surface and near-surface circulation dynamics in this 600 square mile area, during an entire tidal cycle. The analyses of these data in concert with all previous ERTS-1 overpasses will provide information that can lead to a better and more rational use of the nearshore marine environment. The data will be utilized to plan future outfall locations, regulating offshore disposal of wastes, etc.

The impact of extensive green roofs on the improvement of thermal performance for urban areas in Mediterranean climate with reference to the city of Jijel in Algeria

NASA Astrophysics Data System (ADS)

Lehtihet, M. C.; Bouchair, A.

2018-05-01

Buildings with dark surfaces, concrete and pavement, needed for the expansion of cities, absorb huge amounts of heat, increasing the mean radiant temperatures of urban areas and offer significant potential for urban heat island (UHI) effect. The purpose of this work is to investigate the impact of green roofs on the improvement of urban heat performance in Mediterranean climate. A field investigation is carried out using two large-scale modules built in the city of Jijel in the north of Algeria. The first is a bare reinforced concrete slab whereas the second is covered with ivy plants. The experimental site, the air and surface temperature parameters and the various measurement points at the level of the modules are chosen. Measurements are performed using thermo-hygrometer, surface sensors and data acquisition apparatus. The results show that green roofs can be a potential mean of improving the thermal performance of the surrounding microclimate and energy performance of buildings in an urban area. The green roof could be an encouraging strategy against urban heat island effect not only for Mediterranean cities but also for other areas.

Mars Exploration Rovers Entry, Descent, and Landing Trajectory Analysis

NASA Technical Reports Server (NTRS)

Desai, Prasun N.; Knocke, Philip C.

2007-01-01

In this study we present a novel method of land surface classification using surface-reflected GPS signals in combination with digital imagery. Two GPS-derived classification features are merged with visible image data to create terrain-moisture (TM) classes, defined here as visibly identifiable terrain or landcover classes containing a surface/soil moisture component. As compared to using surface imagery alone, classification accuracy is significantly improved for a number of visible classes when adding the GPS-based signal features. Since the strength of the reflected GPS signal is proportional to the amount of moisture in the surface, use of these GPS features provides information about the surface that is not obtainable using visible wavelengths alone. Application areas include hydrology, precision agriculture, and wetlands mapping.

Finite element based contact analysis of radio frequency MEMs switch membrane surfaces

NASA Astrophysics Data System (ADS)

Liu, Jin-Ya; Chalivendra, Vijaya; Huang, Wenzhen

2017-10-01

Finite element simulations were performed to determine the contact behavior of radio frequency (RF) micro-electro-mechanical (MEM) switch contact surfaces under monotonic and cyclic loading conditions. Atomic force microscopy (AFM) was used to capture the topography of RF-MEM switch membranes and later they were analyzed for multi-scale regular as well as fractal structures. Frictionless, non-adhesive contact 3D finite element analysis was carried out at different length scales to investigate the contact behavior of the regular-fractal surface using an elasto-plastic material model. Dominant micro-scale regular patterns were found to significantly change the contact behavior. Contact areas mainly cluster around the regular pattern. The contribution from the fractal structure is not significant. Under cyclic loading conditions, plastic deformation in the 1st loading/unloading cycle smooth the surface. The subsequent repetitive loading/unloading cycles undergo elastic contact without changing the morphology of the contacting surfaces. The work is expected to shed light on the quality of the switch surface contact as well as the optimum design of RF MEM switch surfaces.

What are hot and what are not in an urban landscape: quantifying and explaining the land surface temperature pattern in Beijing, China

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

Kuang, Wenhui; Liu, Yue; Dou, Yinyin

Understanding how landscape components affect the urban heat islands is crucial for urban ecological planning and sustainable development. The purpose of this research was to quantify the spatial pattern of land surface temperatures (LSTs) and associated heat fluxes in relation to land-cover types in Beijing, China, using portable infrared thermometers, thermal infrared imagers, and the moderate resolution imaging spectroradiometer. The spatial differences and the relationships between LSTs and the hierarchical landscape structure were analyzed with in situ observations of surface radiation and heat fluxes. Large LST differences were found among various land-use/land-cover types, urban structures, and building materials. Within themore » urban area, the mean LST of urban impervious surfaces was about 6–12°C higher than that of the urban green space. LSTs of built-up areas were on average 3–6°C higher than LSTs of rural areas. The observations for surface radiation and heat fluxes indicated that the differences were caused by different fractions of sensible heat or latent heat flux in net radiation. LSTs decreased with increasing elevation and normalized difference vegetation index. Variations in building materials and urban structure significantly influenced the spatial pattern of LSTs in urban areas. By contrast, elevation and vegetation cover are the major determinants of the LST pattern in rural areas. In summary, to alleviate urban heat island intensity, urban planners and policy makers should pay special attention to the selection of appropriate building materials, the reasonable arrangement of urban structures, and the rational design of landscape components.« less

Predictors of serum chromium levels after stainless steel posterior spinal instrumentation for adolescent idiopathic scoliosis.

PubMed

Rackham, Matthew D; Cundy, Thomas P; Antoniou, Georgia; Freeman, Brian J C; Sutherland, Leanne M; Cundy, Peter J

2010-04-20

Prospective cohort study. To determine the predictors of serum chromium levels after stainless steel posterior spinal instrumentation for adolescent idiopathic scoliosis. Abnormally elevated serum chromium levels have been detected in patients with adolescent idiopathic scoliosis after stainless steel instrumentation. To date, the relationship among serum chromium levels, time of implantation, and implant characteristics (including surface area, rod length, numbers of hooks, screws, and cross connectors) has not been studied. Thirty patients with adolescent idiopathic scoliosis undergoing posterior instrumented spinal arthrodesis using stainless steel implants between 1998 and 2002 were prospectively studied. Serum chromium levels were measured between October 2006 and June 2007. Postoperative radiographs were used to measure rod lengths, number of hooks, screws, cross-connectors, and cables. The surface area of each component and the total surface area for each patient were calculated. Possible associations between serum chromium levels, time of implantation, and implant characteristics were investigated. Implant exposure, whether expressed in the form of total metal implant surface area, rod length, or number of metal interfaces, was found to be positively associated with serum chromium levels. Specifically, chromium levels increased by a multiplicative factor of 1.0060 for every additional square centimeter of total metal implant surface area (P = 0.02). In addition, the chromium level was found to decrease by a multiplicative factor of 0.7766 for every additional year since surgery (P = 0.02). After adjusting for the number of years since surgery, metal implant exposure is positively associated with elevated serum chromium levels in adolescent idiopathic scoliosis patients with stainless steel posterior spinal implants. This is the first study to identify statistically significant positive associations between specific spinal implant characteristics (other than corrosion identified by radiographs) and serum chromium levels.

What are hot and what are not in an urban landscape: quantifying and explaining the land surface temperature pattern in Beijing, China

DOE PAGES

Kuang, Wenhui; Liu, Yue; Dou, Yinyin; ...

2014-12-06

Understanding how landscape components affect the urban heat islands is crucial for urban ecological planning and sustainable development. The purpose of this research was to quantify the spatial pattern of land surface temperatures (LSTs) and associated heat fluxes in relation to land-cover types in Beijing, China, using portable infrared thermometers, thermal infrared imagers, and the moderate resolution imaging spectroradiometer. The spatial differences and the relationships between LSTs and the hierarchical landscape structure were analyzed with in situ observations of surface radiation and heat fluxes. Large LST differences were found among various land-use/land-cover types, urban structures, and building materials. Within themore » urban area, the mean LST of urban impervious surfaces was about 6–12°C higher than that of the urban green space. LSTs of built-up areas were on average 3–6°C higher than LSTs of rural areas. The observations for surface radiation and heat fluxes indicated that the differences were caused by different fractions of sensible heat or latent heat flux in net radiation. LSTs decreased with increasing elevation and normalized difference vegetation index. Variations in building materials and urban structure significantly influenced the spatial pattern of LSTs in urban areas. By contrast, elevation and vegetation cover are the major determinants of the LST pattern in rural areas. In summary, to alleviate urban heat island intensity, urban planners and policy makers should pay special attention to the selection of appropriate building materials, the reasonable arrangement of urban structures, and the rational design of landscape components.« less

Electrochemical Hydrogen Evolution at Ordered Mo 7 Ni 7

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

Csernica, Peter M.; McKone, James R.; Mulzer, Catherine R.

2017-04-11

Ni–Mo alloys containing up to ~15 mol % Mo are excellent non-noble electrocatalysts for the hydrogen evolution reaction (HER) in alkaline aqueous electrolytes. To date, studies have not addressed the details of HER activity of ordered Ni–Mo intermetallic compounds, which can contain a significantly larger fraction of Mo (up to 50 mol %) than can be accessed through high-temperature alloying. Here, we present a straightforward and facile synthesis of three phase-pure electrocatalyst powders using a precipitation–reduction approach: ordered Mo7Ni7, disordered Ni0.92Mo0.08, and pure Ni. The Ni0.92Mo0.08 alloy exhibited a nearly 10-fold higher mass-specific HER activity than either pure Ni ormore » Mo7Ni7, where much of the difference could be attributed to relative surface area. Therefore, we attempted to quantify and account for differences in surface areas using electron microscopy, impedance spectroscopy, and gas adsorption measurements. These data suggest that Ni–Mo alloys and intermetallic compounds exhibit substantial pseudocapacitance at potentials near the onset of hydrogen evolution, which can cause impedance spectroscopy to overestimate the interfacial capacitance, and thus the electrochemically active surface area, of these materials. From these observations, we postulate Mo redox activity as the chemical basis for the observed pseudocapacitance of Ni–Mo composites. Furthermore, using gas adsorption measurements, rather than capacitance, to estimate active surface area, we find that ordered Mo7Ni7 is more intrinsically active than the Ni0.92Mo0.08 alloy, implying that Mo7Ni7 intermetallics with high surface area will also give higher mass-specific activities than alloys with comparable roughness.« less

Breast Implant-Associated Anaplastic Large Cell Lymphoma in Australia and New Zealand: High-Surface-Area Textured Implants Are Associated with Increased Risk.

PubMed

Loch-Wilkinson, Anna; Beath, Kenneth J; Knight, Robert John William; Wessels, William Louis Fick; Magnusson, Mark; Papadopoulos, Tim; Connell, Tony; Lofts, Julian; Locke, Michelle; Hopper, Ingrid; Cooter, Rodney; Vickery, Karen; Joshi, Preeti Avinash; Prince, H Miles; Deva, Anand K

2017-10-01

The association between breast implants and breast implant-associated anaplastic large cell lymphoma (ALCL) has been confirmed. Implant-related risk has been difficult to estimate to date due to incomplete datasets. All cases in Australia and New Zealand were identified and analyzed. Textured implants reported in this group were subjected to surface area analysis. Sales data from three leading breast implant manufacturers (i.e., Mentor, Allergan, and Silimed) dating back to 1999 were secured to estimate implant-specific risk. Fifty-five cases of breast implant-associated ALCL were diagnosed in Australia and New Zealand between 2007 and 2016. The mean age of patients was 47.1 years and the mean time of implant exposure was 7.46 years. There were four deaths in the series related to mass and/or metastatic presentation. All patients were exposed to textured implants. Surface area analysis confirmed that higher surface area was associated with 64 of the 75 implants used (85.3 percent). Biocell salt loss textured (Allergan, Inamed, and McGhan) implants accounted for 58.7 percent of the implants used in this series. Comparative analysis showed the risk of developing breast implant-associated ALCL to be 14.11 times higher with Biocell textured implants and 10.84 higher with polyurethane (Silimed) textured implants compared with Siltex textured implants. This study has calculated implant-specific risk of breast implant-associated ALCL. Higher-surface-area textured implants have been shown to significantly increase the risk of breast implant-associated ALCL in Australia and New Zealand. The authors present a unifying hypothesis to explain these observations.

Effects of increased apical enlargement on the amount of unprepared areas and coronal dentine removal: a micro-computed tomography study.

PubMed

Pérez, A R; Alves, F R F; Marceliano-Alves, M F; Provenzano, J C; Gonçalves, L S; Neves, A A; Siqueira, J F

2018-06-01

To evaluate the effects of progressive apical enlargement on the amount of unprepared root canal surface area and remaining dentine thickness. The root canals of 30 extracted mandibular incisors with Vertucci's type I configuration were instrumented with rotary HyFlex CM instruments (Coltene-Whaledent, Altstätten, Switzerland) up to 4 instruments larger than the first one that bound at the working length (WL). Teeth were scanned in a micro-computed tomography (micro-CT) device before canal preparation and after instrumentation with the 2nd, 3rd and 4th larger instruments. The amount of unprepared surface area in the full canal or in the apical 4 mm as well as the remaining dentine thickness at 10 mm from the WL were calculated and compared. The general linear model for repeated measures adjusted by Bonferroni's post hoc test was used for statistic analysis. There was a significant reduction in the amount of unprepared areas after each increase in preparation size (P < 0.01). This was observed for both the full canal length and the 4-mm apical segment. The amount of remaining dentine was also significantly reduced after each file size (P < 0.01). However, dentine thickness always remained greater than 1 mm, even after using the largest instrument. Apical preparations up to 4 instruments larger than the first one to bind at the WL caused a significant progressive reduction in the unprepared canal area. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Tribological performance of femtosecond laser-induced periodic surface structures on titanium and a high toughness bearing steel

NASA Astrophysics Data System (ADS)

Bonse, J.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Höhm, S.; Rosenfeld, A.; Krüger, J.

2015-05-01

Laser-induced periodic surface structures (LIPSS, ripples) were processed on steel (X30CrMoN15-1) and titanium (Ti) surfaces by irradiation in air with linear polarized femtosecond laser pulses with a pulse duration of 30 fs at 790 nm wavelength. For the processing of large LIPSS covered surface areas (5 mm × 5 mm), the laser fluence and the spatial spot overlap were optimized in a sample-scanning geometry. The laser-processed surfaces were characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). Spatial LIPSS periods between 450 and 600 nm were determined. The nanostructured surface regions were tribologically tested under reciprocal sliding conditions against a 10-mm diameter ball of hardened 100Cr6 steel. Paraffin oil and engine oil were used as lubricants for 1000 sliding cycles at 1 Hz with a normal load of 1.0 N. The corresponding wear tracks were analyzed by OM and SEM. In particular cases, the laser-generated nanostructures endured the tribological treatment. Simultaneously, a significant reduction of the friction coefficient and the wear was observed in the laser-irradiated (LIPSS-covered) areas when compared to the non-irradiated surface. The experiments reveal the potential benefit of laser surface structuring for tribological applications.

High-resolution microcontact printing and transfer of massive arrays of microorganisms on planar and compartmentalized nanoporous aluminium oxide.

PubMed

Ingham, Colin; Bomer, Johan; Sprenkels, Ad; van den Berg, Albert; de Vos, Willem; van Hylckama Vlieg, Johan

2010-06-07

Handling microorganisms in high throughput and their deployment into miniaturized platforms presents significant challenges. Contact printing can be used to create dense arrays of viable microorganisms. Such "living arrays", potentially with multiple identical replicates, are useful in the selection of improved industrial microorganisms, screening antimicrobials, clinical diagnostics, strain storage, and for research into microbial genetics. A high throughput method to print microorganisms at high density was devised, employing a microscope and a stamp with a massive array of PDMS pins. Viable bacteria (Lactobacillus plantarum, Esherichia coli), yeast (Candida albicans) and fungal spores (Aspergillus fumigatus) were deposited onto porous aluminium oxide (PAO) using arrays of pins with areas from 5 x 5 to 20 x 20 microm. Printing onto PAO with up to 8100 pins of 20 x 20 microm area with 3 replicates was achieved. Printing with up to 200 pins onto PAO culture chips (divided into 40 x 40 microm culture areas) allowed inoculation followed by effective segregation of microcolonies during outgrowth. Additionally, it was possible to print mixtures of C. albicans and spores of A. fumigatus with a degree of selectivity by capture onto a chemically modified PAO surface. High resolution printing of microorganisms within segregated compartments and on functionalized PAO surfaces has significant advantages over what is possible on semi-solid surfaces such as agar.

Topical tocopherol for treatment of reticular oral lichen planus: a randomized, double-blind, crossover study.

PubMed

Bacci, C; Vanzo, V; Frigo, A C; Stellini, E; Sbricoli, L; Valente, M

2017-01-01

This randomized, double-blind, placebo-controlled crossover study assessed the efficacy of topical tocopherol acetate compared with placebo in easing oral discomfort in patients with reticular oral lichen planus (ROLP). Thirty-four patients with clinically diagnosed and histologically confirmed ROLP were randomly assigned to two groups, which received first one of two treatments (treatment 1 or 2) for a month, then the other (treatment 2 or 1) for another month, with a two-week washout between them. One treatment contained tocopherol acetate and the other only liquid paraffin. The primary outcome was less discomfort, measured on a visual analog scale (VAS). Secondary outcomes were as follows: length of striae measured and photographed at each follow-up; surface area of lesions; and a modified Thongprasom score. No statistically significant differences emerged between the two treatments (1 vs 2) in terms of VAS scores (P > 0.05; 0.8624) or length of striae (P = 0.0883). Significant differences were seen for surface area of lesions (P < 0.05, P = 0.0045) and modified Thongprasom scores (P = 0.0052). The two treatments differed only in terms of the surface area of the lesions and Thongprasom scores, not in VAS scores for discomfort or the length of patients' striae. Topical tocopherol proved effective in the treatment of ROLP. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Microbiological survey of a South African poultry processing plant.

PubMed

Geornaras, I; de Jesus, A; van Zyl, E; von Holy, A

1995-01-01

Bacterial populations associated with poultry processing were determined on neck skin samples, equipment surfaces and environmental samples by replicate surveys. Aerobic plate counts, Enterobacteriaceae counts, Enterobacteriaceae counts and Pseudomonas counts were performed by standard procedures and the prevalence of Listeria, presumptive Salmonella and Staphylococcus aureus determined. Statistically significant (P < 0.05) increases in counts of all types of bacteria were obtained on product samples as a result of processing. Although bacterial counts on neck skin samples decreased by 0.3 to 0.4 log CFU g-1 after spray washing of carcasses, subsequent spinchilling and packaging of whole carcasses resulted in 0.7 to 1.2 log CFU g-1 increases. Bacterial numbers on equipment surfaces, however, decreased significantly from the "dirty" to the "clean" areas of the abattoir. Transport cages, "rubber fingers", defeathering curtains, shackles and conveyor belts repeatedly showed aerobic plate counts in excess of 5.0 log CFU 25 cm-2. Aerobic plate counts of scald tank and spinchiller water were 2 log CFU ml-1 higher than those of potable water samples. Bacterial numbers of the air in the "dirty" area were higher than those of the "clean" area. Listeria, presumptive Salmonella and Staphylococcus aureus were isolated from 27.6, 51.7 and 24.1% of all product samples, respectively, and Listeria and Staphylococcus aureus were also isolated from selected equipment surfaces.

Physical properties of root cementum: Part 18. The extent of root resorption after the application of light and heavy controlled rotational orthodontic forces for 4 weeks: a microcomputed tomography study.

PubMed

Wu, Andy T J; Turk, Tamer; Colak, Canan; Elekdağ-Turk, Selma; Jones, Allan S; Petocz, Peter; Darendeliler, M Ali

2011-05-01

The aim of this prospective randomized clinical trial was to quantitatively measure and compare the locations, dimensions, and volume of root resorption craters in human premolars after the application of controlled light and heavy rotational orthodontic forces over a 28-day (4-week) period. Fifteen patients requiring bilateral extraction of maxillary first premolars as part of their orthodontic treatment were recruited for this study. Each patient received a heavy (225 g) rotational force on 1 premolar and a light (25 g) rotational force on the contralateral premolar. Orthodontic rotational forces were applied over 28 days with buccal and palatal cantilever springs; 0.016-inch beta-titanium molybdenum alloys were used to apply the light force and 0.018-inch stainless steel was used for the heavy force. After the 28-day experimental period, the upper first premolars were extracted under stringent protocols to prevent root surface damage. The samples were then scanned using a microcomputed tomography (micro-CT) scan x-ray system (SkyScan 1072, Skyscan, Aartselaar, Belgium), and analyzed using convex hull algorithm (CHULL2D; University of Sydney, Sydney, Australia) software to obtain direct volumetric measurements. The mean volume of resorption craters was 0.42 in the light force group and 0.51 in the heavy force group (P = 0.013). When separated at the root level, the difference in volume of root resorption craters between the 2 groups was significantly different only at the midlevel (P = 0.001). Root resorption craters were consistently detected at the boundaries between the buccal and distal surfaces and the mesial and lingual surfaces. The result supports our hypothesis that positive areas develop significantly more root resorption craters at all 3 levels, as compared with minimal areas (paired t test <0.001). Heavy rotational forces caused more root resorption than light rotational forces and compression areas (buccal-distal and lingual-mesial surfaces in this study) showed significantly higher root resorption than other areas at all levels of the root. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Influence of the Hyporheic Zone on Supersaturated Gas Exposure to Incubating Chum Salmon

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

Arntzen, Evan V.; Geist, David R.; Murray, Katherine J.

2009-12-01

Supersaturated total dissolved gas (TDG) is elevated seasonally in the lower Columbia River, with surface water concentrations approaching 120% saturation of TDG. Chum salmon (Oncorhynchus keta) embryos incubating in nearby spawning areas could be affected if depth-compensated TDG concentrations within the hyporheic zone exceed 103% TDG. The objective of this study was to determine if TDG of the hyporheic zone in two chum salmon spawning areas -- one in a side channel near Ives Island, Washington, and another on the mainstem Columbia River near Multnomah Falls, Oregon -- was affected by the elevated TDG of the surface water. Depth-compensated hyporheicmore » TDG did not exceed 103% at the Multnomah Falls site. However, in the Ives Island area, chum salmon redds were exposed to TDG greater than 103% for more than 600 hours. In response to river depth fluctuations, TDG varied significantly in the Ives Island area, suggesting increased interaction between the hyporheic zone and surface water at that site. We conclude from this study that the interaction between surface water and the hyporheic zone affects the concentration of TDG within the hyporheic zone directly via physical mixing as well as indirectly by altering water chemistry and thus dissolved gas solubility. These interactions are important considerations when estimating TDG exposure within egg pocket environments, facilitating improved exposure estimates, and enabling managers to optimize recovery strategies.« less

Land surface phenology of Northeast China during 2000-2015: temporal changes and relationships with climate changes.

PubMed

Zhang, Yue; Li, Lin; Wang, Hongbin; Zhang, Yao; Wang, Naijia; Chen, Junpeng

2017-10-01

As an important crop growing area, Northeast China (NEC) plays a vital role in China's food security, which has been severely affected by climate change in recent years. Vegetation phenology in this region is sensitive to climate change, and currently, the relationship between the phenology of NEC and climate change remains unclear. In this study, we used a satellite-derived normalized difference vegetation index (NDVI) to obtain the temporal patterns of the land surface phenology in NEC from 2000 to 2015 and validated the results using ground phenology observations. We then explored the relationships among land surface phenology, temperature, precipitation, and sunshine hours for relevant periods. Our results showed that the NEC experienced great phenological changes in terms of spatial heterogeneity during 2000-2015. The spatial patterns of land surface phenology mainly changed with altitude and land cover type. In most regions of NEC, the start date of land surface phenology had advanced by approximately 1.0 days year -1 , and the length of land surface phenology had been prolonged by approximately 1.0 days year -1 except for the needle-leaf and cropland areas, due to the warm conditions. We found that a distinct inter-annual variation in land surface phenology related to climate variables, even if some areas presented non-significant trends. Land surface phenology was coupled with climate variables and distinct responses at different combinations of temperature, precipitation, sunshine hours, altitude, and anthropogenic influence. These findings suggest that remote sensing and our phenology extracting methods hold great potential for helping to understand how land surface phenology is sensitive to global climate change.

Area-averaged evapotranspiration over a heterogeneous land surface: aggregation of multi-point EC flux measurements with a high-resolution land-cover map and footprint analysis

NASA Astrophysics Data System (ADS)

Xu, Feinan; Wang, Weizhen; Wang, Jiemin; Xu, Ziwei; Qi, Yuan; Wu, Yueru

2017-08-01

The determination of area-averaged evapotranspiration (ET) at the satellite pixel scale/model grid scale over a heterogeneous land surface plays a significant role in developing and improving the parameterization schemes of the remote sensing based ET estimation models and general hydro-meteorological models. The Heihe Watershed Allied Telemetry Experimental Research (HiWATER) flux matrix provided a unique opportunity to build an aggregation scheme for area-averaged fluxes. On the basis of the HiWATER flux matrix dataset and high-resolution land-cover map, this study focused on estimating the area-averaged ET over a heterogeneous landscape with footprint analysis and multivariate regression. The procedure is as follows. Firstly, quality control and uncertainty estimation for the data of the flux matrix, including 17 eddy-covariance (EC) sites and four groups of large-aperture scintillometers (LASs), were carefully done. Secondly, the representativeness of each EC site was quantitatively evaluated; footprint analysis was also performed for each LAS path. Thirdly, based on the high-resolution land-cover map derived from aircraft remote sensing, a flux aggregation method was established combining footprint analysis and multiple-linear regression. Then, the area-averaged sensible heat fluxes obtained from the EC flux matrix were validated by the LAS measurements. Finally, the area-averaged ET of the kernel experimental area of HiWATER was estimated. Compared with the formerly used and rather simple approaches, such as the arithmetic average and area-weighted methods, the present scheme is not only with a much better database, but also has a solid grounding in physics and mathematics in the integration of area-averaged fluxes over a heterogeneous surface. Results from this study, both instantaneous and daily ET at the satellite pixel scale, can be used for the validation of relevant remote sensing models and land surface process models. Furthermore, this work will be extended to the water balance study of the whole Heihe River basin.

Preliminary Study on Earthquake Surface Rupture Extraction from Uav Images

NASA Astrophysics Data System (ADS)

Yuan, X.; Wang, X.; Ding, X.; Wu, X.; Dou, A.; Wang, S.

2018-04-01

Because of the advantages of low-cost, lightweight and photography under the cloud, UAVs have been widely used in the field of seismic geomorphology research in recent years. Earthquake surface rupture is a typical seismic tectonic geomorphology that reflects the dynamic and kinematic characteristics of crustal movement. The quick identification of earthquake surface rupture is of great significance for understanding the mechanism of earthquake occurrence, disasters distribution and scale. Using integrated differential UAV platform, series images were acquired with accuracy POS around the former urban area (Qushan town) of Beichuan County as the area stricken seriously by the 2008 Wenchuan Ms8.0 earthquake. Based on the multi-view 3D reconstruction technique, the high resolution DSM and DOM are obtained from differential UAV images. Through the shade-relief map and aspect map derived from DSM, the earthquake surface rupture is extracted and analyzed. The results show that the surface rupture can still be identified by using the UAV images although the time of earthquake elapse is longer, whose middle segment is characterized by vertical movement caused by compression deformation from fault planes.

On the methane paradox: Transport from shallow water zones rather than in situ methanogenesis is the major source of CH4 in the open surface water of lakes

NASA Astrophysics Data System (ADS)

Encinas Fernández, Jorge; Peeters, Frank; Hofmann, Hilmar

2016-10-01

Estimates of global methane (CH4) emissions from lakes and the contributions of different pathways are currently under debate. In situ methanogenesis linked to algae growth was recently suggested to be the major source of CH4 fluxes from aquatic systems. However, based on our very large data set on CH4 distributions within lakes, we demonstrate here that methane-enriched water from shallow water zones is the most likely source of the basin-wide mean CH4 concentrations in the surface water of lakes. Consistently, the mean surface CH4 concentrations are significantly correlated with the ratio between the surface area of the shallow water zone and the entire lake, fA,s/t, but not with the total surface area. The categorization of CH4 fluxes according to fA,s/t may therefore improve global estimates of CH4 emissions from lakes. Furthermore, CH4 concentrations increase substantially with water temperature, indicating that seasonally resolved data are required to accurately estimate annual CH4 emissions.

Sensitivity of U.S. surface ozone to future emissions and climate changes

NASA Astrophysics Data System (ADS)

Tao, Zhining; Williams, Allen; Huang, Ho-Chun; Caughey, Michael; Liang, Xin-Zhong

2007-04-01

The relative contributions of projected future emissions and climate changes to U.S. surface ozone concentrations are investigated focusing on California, the Midwest, the Northeast, and Texas. By 2050 regional average ozone concentrations increase by 2-15% under the IPCC SRES A1Fi (``dirty'') scenario, and decrease by 4-12% under the B1 (relatively ``clean'') scenario. However, the magnitudes of ozone changes differ significantly between major metropolitan and rural areas. These ozone changes are dominated by the emissions changes in 61% area of the contiguous U.S. under the B1 scenario, but are largely determined by the projected climate changes in 46% area under the A1Fi scenario. In the ozone responses to climate changes, the biogenic emissions changes contribute strongly over the Northeast, moderately in the Midwest, and negligibly in other regions.

Novel use of a Dektak 150 surface profiler unmasks differences in resorption pit profiles between control and Charcot patient osteoclasts.

PubMed

Petrova, Nina L; Petrov, Peter K; Edmonds, Michael E; Shanahan, Catherine M

2014-04-01

We hypothesized that newly formed osteoclasts from patients with acute Charcot osteoarthropathy can resorb surfaces of bone more extensively compared with controls. Peripheral blood monocytes, isolated from eight Charcot patients and nine controls, were cultured in vitro on 24-well plates and bovine bone discs in duplicate with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor κβ ligand (RANKL). Osteoclast formation was assessed by tartrate-resistant acid phosphatase staining (TRAcP) at day 17. Resorption was measured at day 21 after toluidine blue staining by two methods: (1) area of resorption at the surface by image analysis (%) and (2) area of resorption under the surface (μm(2)) measured by a Dektak 150 Surface Profiler. Ten 1,000 μm-long scans were performed per disc. Pits were classified as unidented, bidented, and multidented according to their shape. Although the number of newly formed TRAcP positive multinucleated cells (>3 nuclei) was similar in M-CSF + RANKL-treated cultures between controls and Charcot patients, the latter exhibited increased resorbing activity. The area of resorption on the surface by image analysis was significantly greater in Charcot patients compared with controls (21.1 % [14.5-26.2] vs. 40.8 % [35.4-46.0], median [25-75th percentile], p < 0.01), as was the area of resorption under the surface (2.7 x 10(3) μm(2) [1.6 x 10(3)- 3.9 x 10(3)] vs. 8.3 x 10(3) μm (2) [5.6 x 10(3)- 10.6 x 10(3), [corrected] p < 0.01) after profilometry. In Charcot patients pits were deeper and wider and more frequently presented as multidented pits. This application of the Dektak 150 Surface Profiler revealed novel differences in resorption pit profile from osteoclasts derived from Charcot patients compared with controls. Resorption in Charcot patients was mediated by highly aggressive newly formed osteoclasts from monocytes eroding large and deep areas of bone.

Quantifying the Significance of Heterogeneity in Supraglacial Reflectance Characteristics for Meltwater Production in Southwest Greenland

NASA Astrophysics Data System (ADS)

Irvine-Fynn, T. D.; Bunting, P.; Cook, J.; Hardy, A. J.; Hodson, A. J.; Holt, T.; Hubbard, A.; Naegeli, K.; Nilsson, J.; Ryan, J.; Roberts, O.; Tedstone, A.; Tranter, M.; Williamson, C.

2017-12-01

The seasonal melt on the southwestern margin of the Greenland Ice Sheet has been enhanced due to processes affecting the ablation area's ice surface reflectance (albedo). Recent trends in surface reflectance in the region suggest a decline potentially linked to an albedo-feedback associated with regional climate warming, emergence of organic and mineral particulates, and expansion of melt area. However, the heterogeneity of reflectance over bare ice areas in space and time has remained relatively poorly characterised. Numerous surface mass balance models utilise albedo products derived from remote sensing platforms with coarse scale resolution. Such products provide reasonable albedo estimates, but quantification of local variability in reflectance remains lacking. Consequently, there is a need to better define the distribution and representativeness of ice surface reflectance at and below the scale of satellite sensor pixel footprints to facilitate examination of albedo parameterisations. Here, we present reflectance data repeatedly collected in SW Greenland during the 2016 summer melt season over a 0.0625 km2 area proximate to the IMAU K-transect site S6 (67°04.5'N, 49°21.0'W). The Moderate Resolution Imaging Spectrometer (MODIS) albedo product MOD10A1(c6) for the study site was compared to reflectance data from Sentinel-2, centimetre resolution calibrated 12Mpix optical imagery collected using an Unmanned Aerial Vehicle (UAV) flown at a height of 70 m above the ice surface, and ground-based reflectance survey data acquired using a StellarNet Red-Dwarf/Blue-Wave visible-infrared dual system (250-1700nm) at 30 sites distributed over the area of interest. Our data highlight variability in the spatial distribution of ice surface reflectance characteristics over time. Specifically, data demonstrate marked changes in the distribution of reflectance values, despite maintaining a broadly equitable mean and median during July and August. The influence of the varied surface heterogeneity is explored further using surface energy balance modelling to quantify the impact of such changes on melt production. The findings determine the necessity to account for local variability underlying the pixel-averaged values retrieved from remote sensing platforms such as MODIS.

Modeling Linkages Between Effective Impervious Surface and Urban Vegetation Productivity in Semi-arid Environments

NASA Astrophysics Data System (ADS)

Shields, C. A.; Tague, C.

2010-12-01

With a majority of the world's population now living in urban areas, the role of vegetation in urban ecosystems warrants increased attention. We address the question of how the fine scale (<5m) spatial arrangement of impervious surfaces affects water available to vegetation, which in turn can significantly impact the productivity of vegetation and uptake of C and N. To gain insight into how landscape features influence vegetation productivity, we use a coupled ecohydrogic model to estimate impacts of the amount and arrangement of impervious surfaces on vegetation water use. We use the model to explore how concepts from research in natural semi-arid ecosystems can be applied in the urban context. Ecological research in semi-arid ecosystems has shown that the arrangement of vegetated and bare surfaces plays a key role in regulating both runoff and ecosystem water use and productivity. Systems that include a mixture of bare and vegetated surfaces, for example, tend to show less runoff and more productivity than those with more homogeneous cover. In some instances, patchiness of bare and vegetated surfaces is more important than total vegetated area in determining rates of runoff and vegetation use of rainfall. In an urban context, impervious surfaces can be viewed as analogous to the bare surfaces present in undeveloped ecosystems. We consider not only the total impervious area (TIA), but also the effect of impervious area with a direct hydrologic connection to the stream network, effective impervious area (EIA). While increases in total impervious area (TIA) have been widely shown to impact catchment hydrology, the role of effective impervious area (EIA) has been less extensively studied. A consensus is emerging from the literature that EIA is as important or even more important than TIA as an indicator of catchment response to urbanization. Ecohydrologic models offer a tool to quantify the role of EIA on water availability and plant productivity and demonstrate the potential of urban areas to act as C or N sinks (and minimize the impacts such as increased storm runoff and degraded downstream water quality). We explore the relative roles of TIA and EIA on water availability and plant productivity in a semi-arid urban environment through a series of modeling exercises. The Regional HydroEcological Simulation System (RHESSys) is used to model a range of impervious surface and vegetation scenarios on a test hillslope in the Mission Creek catchment in Santa Barbara CA. Results indicate that reduced EIA can indeed act to mitigate the impact of TIA on water available to plants. We then implement a modification to the RHESSys model that incorporates patch scale estimates of EIA into simulations of the entire Mission Creek catchment, allowing us to quantify likely catchment-scale impacts of altering EIA.

Evaluation of the Surface Treatment on Bone Healing in a Transmucosal 1-mm Area of Implant Abutment: An Experimental Study in the Rabbit Tibia.

PubMed

Gehrke, Sergio Alexandre; da Silva Neto, Ulisses Tavares

2016-06-01

The objective of the present study was to investigate the effect on bone tissue healing patterns in 1-mm area treated in the transmucosal surface of the abutment in the tibia of rabbits. Forty-six abutments were divided into two groups: control group (CG) with 14 abutments with smooth surface and experimental group (EG) with 32 abutments presenting a 1-mm area of the transmucosal surface treated through sandblasting with microparticles of titanium oxide followed by acid etching. Five samples of each group were analyzed using an optical laser profilometer for surface roughness characterization. Thirty-six Morse taper implants (3.5 mm in diameter and 7 mm in length) were inserted 1.5 mm subcrestal into the tibiae of nine rabbits. The implants were removed after 8, 10, and 12 weeks for histological analysis. The histological slides were prepared and analyzed qualitatively in relation to the new bone at the interface bone-abutment and quantitatively, in relation to bone height from the base of the implant. These data were computed and statistically compared inside the groups using analysis of variance and the U-test between groups for same time. Both groups exhibited bone growth in the direction and over the surface of the abutments, with good healing. However, the EG group showed an increased height of bone formation in the crestal direction, and highly significant differences were observed (p < .001) between these measured values. Under the limitations of the present study, histological follow-up at 8, 10, and 12 weeks showed that transmucosal 1-mm area of implant abutment with treatment of the surface facilitated the maintenance of bone height around the abutment compared with the same abutment with the totally smooth surface. © 2015 Wiley Periodicals, Inc.

Impact of Middle vs. Inferior Total Turbinectomy on Nasal Aerodynamics

PubMed Central

Dayal, Anupriya; Rhee, John S.; Garcia, Guilherme J. M.

2016-01-01

Objectives This computational study aims to: (1) Use virtual surgery to theoretically investigate the maximum possible change in nasal aerodynamics after turbinate surgery; (2) Quantify the relative contributions of the middle and inferior turbinates to nasal resistance and air conditioning; (3) Quantify to what extent total turbinectomy impairs the nasal air conditioning capacity. Study Design Virtual surgery and computational fluid dynamics (CFD). Setting Academic tertiary medical center. Subjects and Methods Ten patients with inferior turbinate hypertrophy were studied. Three-dimensional models of their nasal anatomies were built based on pre-surgery computed tomography scans. Virtual surgery was applied to create models representing either total inferior turbinectomy (TIT) or total middle turbinectomy (TMT). Airflow, heat transfer, and humidity transport were simulated at a 15 L/min steady-state inhalation rate. The surface area stimulated by mucosal cooling was defined as the area where heat fluxes exceed 50 W/cm2. Results In both virtual total turbinectomy models, nasal resistance decreased and airflow increased. However, the surface area where heat fluxes exceed 50 W/cm2 either decreased (TIT) or did not change significantly (TMT), suggesting that total turbinectomy may reduce the stimulation of cold receptors by inspired air. Nasal heating and humidification efficiencies decreased significantly after both TIT and TMT. All changes were greater in the TIT models than in the TMT models. Conclusion TIT yields greater increases in nasal airflow, but also impairs the nasal air conditioning capacity to a greater extent than TMT. Radical resection of the turbinates may decrease the surface area stimulated by mucosal cooling. PMID:27165673

Impact of Middle versus Inferior Total Turbinectomy on Nasal Aerodynamics.

PubMed

Dayal, Anupriya; Rhee, John S; Garcia, Guilherme J M

2016-09-01

This computational study aims to (1) use virtual surgery to theoretically investigate the maximum possible change in nasal aerodynamics after turbinate surgery, (2) quantify the relative contributions of the middle and inferior turbinates to nasal resistance and air conditioning, and (3) quantify to what extent total turbinectomy impairs the nasal air-conditioning capacity. Virtual surgery and computational fluid dynamics. Academic tertiary medical center. Ten patients with inferior turbinate hypertrophy were studied. Three-dimensional models of their nasal anatomies were built according to presurgery computed tomography scans. Virtual surgery was applied to create models representing either total inferior turbinectomy (TIT) or total middle turbinectomy (TMT). Airflow, heat transfer, and humidity transport were simulated at a steady-state inhalation rate of 15 L/min. The surface area stimulated by mucosal cooling was defined as the area where heat fluxes exceed 50 W/m(2). In both virtual total turbinectomy models, nasal resistance decreased and airflow increased. However, the surface area where heat fluxes exceed 50 W/m(2) either decreased (TIT) or did not change significantly (TMT), suggesting that total turbinectomy may reduce the stimulation of cold receptors by inspired air. Nasal heating and humidification efficiencies decreased significantly after both TIT and TMT. All changes were greater in the TIT models than in the TMT models. TIT yields greater increases in nasal airflow but also impairs the nasal air-conditioning capacity to a greater extent than TMT. Radical resection of the turbinates may decrease the surface area stimulated by mucosal cooling. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

Superacid Passivation of Crystalline Silicon Surfaces.

PubMed

Bullock, James; Kiriya, Daisuke; Grant, Nicholas; Azcatl, Angelica; Hettick, Mark; Kho, Teng; Phang, Pheng; Sio, Hang C; Yan, Di; Macdonald, Daniel; Quevedo-Lopez, Manuel A; Wallace, Robert M; Cuevas, Andres; Javey, Ali

2016-09-14

The reduction of parasitic recombination processes commonly occurring within the silicon crystal and at its surfaces is of primary importance in crystalline silicon devices, particularly in photovoltaics. Here we explore a simple, room temperature treatment, involving a nonaqueous solution of the superacid bis(trifluoromethane)sulfonimide, to temporarily deactivate recombination centers at the surface. We show that this treatment leads to a significant enhancement in optoelectronic properties of the silicon wafer, attaining a level of surface passivation in line with state-of-the-art dielectric passivation films. Finally, we demonstrate its advantage as a bulk lifetime and process cleanliness monitor, establishing its compatibility with large area photoluminescence imaging in the process.

Water temperature differences by plant community and location in re-established wetlands in the Sacramento-San Joaquin Delta, California, July 2005 to February 2008

USGS Publications Warehouse

Crepeau, Kathryn L.; Miller, Robin L.

2014-01-01

Rates of carbon storage in wetlands are determined by the balance of its inputs and losses, both of which are affected by environmental factors such as water temperature and depth. In the autumn of 1997, the U.S. Geological Survey re-established two wetlands with different shallow water depths—about 25 and 55 centimeters deep—to investigate the potential to reverse subsidence of delta islands by preserving and accumulating organic substrates derived from plant biomass inputs over time. Because cooler water temperatures can slow decomposition rates and increase accretion of plant biomass, water temperature was recorded from July 2005 to February 2008 in the deeper of the two wetlands, where areas of emergent and submerged vegetation persisted throughout the study, to assess differences in water temperature between the two vegetation types. Water temperature was compared at three depths in the water column between areas of emergent and submerged vegetation and between areas near the water inflow and in the wetland interior in both vegetation types. The latter comparison was a way of evaluating the effect of the length of time water had resided in the wetland on water temperatures. There were statistically significant differences in water temperature at all depths between the two vegetation types. Overall, in areas of emergent marsh vegetation, the mean water temperature at the surface was 1.4 degrees Celsius (°C) less than it was in areas of submerged vegetation; however, when analyses accounted for the changes in temperature due to seasonal and diurnal cycles, differences in the mean water temperature between the vegetation types were even greater than this. For example, in the spring, the mean temperatures in areas of emergent marsh vegetation at the surface, mid-point, and near the sediment in the water column were 2.0, 2.3, and 2.1 °C less, respectively, than water temperatures in areas of submerged vegetation. When diurnal changes in temperature were accounted for by comparing temperatures in mid-afternoon (at 3 p.m.), water-temperature differences were even greater than the seasonal means indicated. In areas of emergent vegetation, the mean temperatures were cooler than temperatures in areas of submerged vegetation at the surface, the mid-point, and near the sediment in the water column by 3.9, 3.6, and 2.3 °C, respectively. Furthermore, from July 2005 through December 2006, water temperatures at the surface in the interior of the wetland were significantly cooler than in areas near the inflow supplying water from the San Joaquin River by 1.0 °C in areas of submerged vegetation and by 1.1 °C in areas of emergent vegetation.

Seasonality of climate change and oscillations in the Northeast Asia and Northwest Pacific

NASA Astrophysics Data System (ADS)

Ponomarev, V.; Salomatin, A.; Kaplunenko, D.; Krokhin, V.

2003-04-01

The main goals of this study are to estimate and compare the seasonality of centennial/semi-centennial climatic tendencies and dominated oscillations in surface air temperature and precipitation over continental and marginal areas of the Northeast Asia, as well as in the Northwest Pacific SST. We use monthly mean data for the 20th century from the NOAA Global History Climatic Network, JMA data base and WMU/COADS World Atlas of Surface Marine Data. Details of climate change/oscillations associated with cooling or warming in different areas and periods of a year are revealed. Wavelet analyses and two methods of the linear trend estimation are applied. First one is least-squares (LS) method with Fisher’s test for statistical significance level. Second one is nonparametric robust (NR) method, based on Theil's rank regression and Kendall's test for statistical significance level. The NR method should be applied to time series with abnormal distribution function typical for precipitation time series. Application of the NR method result in increase the statistical significance of both positive and negative linear trends in all cases of abnormal distribution with negative/positive skewness and low/high kurtosis. Using this method, we have determined spatial patterns of statistically significant climatic trends in surface air temperature, precipitation in the Northeast Asia, and in the Northwest Pacific SST. The most substantial centennial warming in the vast continental area of the mid-latitude band is found mainly for December March. The semi-centennial/ centennial cooling occurs in South Siberia and the subarctic mid-continental area in June September. Opposite tendencies were also revealed in precipitation and SST. Positive semi-centennial tendency in the SST in the second half of the 20th century predominates in the Kuroshio region and in the northwestern area of the subarctic gyre in winter. Negative tendency in the SST dominates in the southwestern subarctic gyre and the offshore area of the subtropic gyre in summer. Comparison of air temperature, precipitation, SST trends and oscillations in different seasons over land marginal and continental areas, as well as in the subarctic and subtropic zones indicates general features of the Northeast Asian Monsoon change/oscillation in 20th century and its second half. Similar features of seasonality in centennial, semi-centennial trends and dominated oscillations are manifested. Climate change and oscillation in the Northwest Pacific marginal seas revealed for the 20th century are explained.

Seasonality of climate change and oscillations in the Northeast Asia and Northwest Pacific

NASA Astrophysics Data System (ADS)

Ponomarev, V.; Salomatin, A.; Kaplunenko, D.; Krokhin, V.

2003-04-01

The main goals of this study are to estimate and compare the centennial/semi-centennial climatic tendencies and oscillations in surface air temperature and precipitation over continental and marginal areas of the Northeast Asian, as well as in the Northwest Pacific SST for all months of a year. We use monthly mean data for the 20th century from the NOAA Global History Climatic Network, JMA data base and WMU/COADS World Atlas of Surface Marine Data. Details of climate change/oscillations associated with cooling or warming in different areas and periods of a year are revealed. Wavelet analyses and two methods of the linear trend estimation are applied. First one is least-squares (LS) method with Fisher’s test for statistical significance level. Second one is nonparametric robust (NR) method, based on Theil's rank regression and Kendall's test for statistical significance level. The NR method should be applied to time series with abnormal distribution function typical for precipitation time series. Application of the NR method result in increase the statistical significance of both positive and negative linear trends in all cases of abnormal distribution with negative/positive skewness and low/high kurtosis. Using this method, we have determined spatial patterns of statistically significant climatic trends in surface air temperature, precipitation in the Northeast Asia, and in the Northwest Pacific SST. The most substantial centennial warming in the vast continental area of the mid-latitude band is found mainly for December March. The semi-centennial/ centennial cooling occurs in South Siberia and the subarctic mid-continental area in June September. Opposite tendencies were also revealed in precipitation and SST. Positive semi-centennial tendency in the SST in the second half of the 20th century predominates in the Kuroshio region and in the northwestern area of the subarctic gyre in winter. Negative tendency in the SST dominates in the southwestern subarctic gyre and the offshore area of the subtropic gyre in summer. Comparison of air temperature, precipitation, SST trends and oscillations in different seasons over land marginal and continental areas, as well as in the subarctic and subtropic zones indicates general features of the Northeast Asian Monsoon change/oscillation in 20th century and its second half. Similar features of seasonality in centennial, semi-centennial trends and dominated oscillations are manifested. Climate change and oscillation in the Northwest Pacific marginal seas revealed for the 20th century are explained.

Histopathological Validation of the Surface-Intermediate-Base Margin Score for Standardized Reporting of Resection Technique during Nephron Sparing Surgery.

PubMed

Minervini, Andrea; Campi, Riccardo; Kutikov, Alexander; Montagnani, Ilaria; Sessa, Francesco; Serni, Sergio; Raspollini, Maria Rosaria; Carini, Marco

2015-10-01

The surface-intermediate-base margin score is a novel standardized reporting system of resection techniques during nephron sparing surgery. We validated the surgeon assessed surface-intermediate-base score with microscopic histopathological assessment of partial nephrectomy specimens. Between June and August 2014 data were prospectively collected from 40 consecutive patients undergoing nephron sparing surgery. The surface-intermediate-base score was assigned to all cases. The score specific areas were color coded with tissue margin ink and sectioned for histological evaluation of healthy renal margin thickness. Maximum, minimum and mean thickness of healthy renal margin for each score specific area grade (surface [S] = 0, S = 1 ; intermediate [I] or base [B] = 0, I or B = 1, I or B = 2) was reported. The Mann-Whitney U and Kruskal-Wallis tests were used to compare the thickness of healthy renal margin in S = 0 vs 1 and I or B = 0 vs 1 vs 2 grades, respectively. Maximum, minimum and mean thickness of healthy renal margin was significantly different among score specific area grades S = 0 vs 1, and I or B = 0 vs 1, 0 vs 2 and 1 vs 2 (p <0.001). The main limitations of the study are the low number of the I or B = 1 and I or B = 2 samples and the assumption that each microscopic slide reflects the entire score specific area for histological analysis. The surface-intermediate-base scoring method can be readily harnessed in real-world clinical practice and accurately mirrors histopathological analysis for quantification and reporting of healthy renal margin thickness removed during tumor excision. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Subcortical volume and cortical surface architecture in women with acute and remitted anorexia nervosa: An exploratory neuroimaging study.

PubMed

Miles, Amy E; Voineskos, Aristotle N; French, Leon; Kaplan, Allan S

2018-07-01

Anorexia nervosa (AN) is a highly heritable psychiatric disorder characterized by starvation and emaciation and associated with changes in brain structure. The precise nature of these changes remains unclear, as does their developmental time course and capacity for reversal with weight-restoration. In this comprehensive neuroimaging study, we sought to characterize these changes by measuring subcortical volume and cortical surface architecture in women with acute and remitted AN. Structural magnetic resonance imaging data was acquired from underweight women with a current diagnosis of AN (acAN: n = 23), weight-recovered women with a past diagnosis of AN (recAN: n = 24), and female controls (HC: n = 24). Subcortical segmentation and cortical surface reconstruction were performed with FreeSurfer 6.0.0, and group differences in regional volume and vertex-wise, cortex-wide thickness, surface area, and local gyrification index (LGI), a measure of folding, were tested with separate univariate analyses of covariance. Mean hippocampal and thalamic volumes were significantly reduced in acAN participants, as was mean cortical thickness in four frontal and temporal clusters. Mean LGI was significantly reduced in acAN and recAN participants in five frontal and parietal clusters. No significant group differences in cortical surface area were detected. Reductions in subcortical volume, cortical thickness, and right postcentral LGI were unique to women with acute AN, indicating state-dependence and pointing towards cellular remodeling and sulcal widening as consequences of disease manifestation. Reductions in bilateral frontal LGI were observed in women with acute and remitted AN, suggesting a role of atypical neurodevelopment in disease vulnerability. Copyright © 2018. Published by Elsevier Ltd.

Optimal graph based segmentation using flow lines with application to airway wall segmentation.

PubMed

Petersen, Jens; Nielsen, Mads; Lo, Pechin; Saghir, Zaigham; Dirksen, Asger; de Bruijne, Marleen

2011-01-01

This paper introduces a novel optimal graph construction method that is applicable to multi-dimensional, multi-surface segmentation problems. Such problems are often solved by refining an initial coarse surface within the space given by graph columns. Conventional columns are not well suited for surfaces with high curvature or complex shapes but the proposed columns, based on properly generated flow lines, which are non-intersecting, guarantee solutions that do not self-intersect and are better able to handle such surfaces. The method is applied to segment human airway walls in computed tomography images. Comparison with manual annotations on 649 cross-sectional images from 15 different subjects shows significantly smaller contour distances and larger area of overlap than are obtained with recently published graph based methods. Airway abnormality measurements obtained with the method on 480 scan pairs from a lung cancer screening trial are reproducible and correlate significantly with lung function.