WorldWideScience

Sample records for surface load variations

  1. Variations in solids loadings to roadside gully pots

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J.B.; Harrop, D.O.

    1984-02-15

    The contribution and composition of road surface particulate loadings as received by roadside gully pots is assessed together with the influences of rainfall and highway surface runoff characteristics. Sediments are well sorted with almost 90% of sediment grading curves lying within a narrow distribution band. Organic grading curves show a distinct diminution in grain sizes, with 10% organic material and 25% bitumen content associated with particulates less than 60 microns. Sediment removal rates showed a seasonal variation which was strongly influenced by both rainfall and surface flow characteristics. The antecedent dry period length appears to have only a minor affect upon the availability of road surface sediments. (A.V.)

  2. Dust Load on Surfaces in Animal Buildings

    DEFF Research Database (Denmark)

    Lengweiler, P.; Strøm, J. S.; Takai, H.

    To investigate the physical process of particle deposition on and resuspension from surfaces in animal buildings, a test facility and a sampling method is established. The influences of surface orientation and air turbulence and velocity just as other parameters on the dust load on a surface...

  3. an investigation into the applicability of natural load variation ...

    African Journals Online (AJOL)

    The present work explores the potentials of natural load variation scheme as a low cost option that is capable of estimating the actual yield of PV modules. Essentially, the scheme consists of a firmware controlling the switching of a number of resistors(loads) connected in parallel. By looping through the resistors in parallel, ...

  4. Bayesian techniques for surface fuel loading estimation

    Science.gov (United States)

    Kathy Gray; Robert Keane; Ryan Karpisz; Alyssa Pedersen; Rick Brown; Taylor Russell

    2016-01-01

    A study by Keane and Gray (2013) compared three sampling techniques for estimating surface fine woody fuels. Known amounts of fine woody fuel were distributed on a parking lot, and researchers estimated the loadings using different sampling techniques. An important result was that precise estimates of biomass required intensive sampling for both the planar intercept...

  5. Surface instabilities in shock loaded granular media

    Science.gov (United States)

    Kandan, K.; Khaderi, S. N.; Wadley, H. N. G.; Deshpande, V. S.

    2017-12-01

    The initiation and growth of instabilities in granular materials loaded by air shock waves are investigated via shock-tube experiments and numerical calculations. Three types of granular media, dry sand, water-saturated sand and a granular solid comprising PTFE spheres were experimentally investigated by air shock loading slugs of these materials in a transparent shock tube. Under all shock pressures considered here, the free-standing dry sand slugs remained stable while the shock loaded surface of the water-saturated sand slug became unstable resulting in mixing of the shocked air and the granular material. By contrast, the PTFE slugs were stable at low pressures but displayed instabilities similar to the water-saturated sand slugs at higher shock pressures. The distal surfaces of the slugs remained stable under all conditions considered here. Eulerian fluid/solid interaction calculations, with the granular material modelled as a Drucker-Prager solid, reproduced the onset of the instabilities as seen in the experiments to a high level of accuracy. These calculations showed that the shock pressures to initiate instabilities increased with increasing material friction and decreasing yield strain. Moreover, the high Atwood number for this problem implied that fluid/solid interaction effects were small, and the initiation of the instability is adequately captured by directly applying a pressure on the slug surface. Lagrangian calculations with the directly applied pressures demonstrated that the instability was caused by spatial pressure gradients created by initial surface perturbations. Surface instabilities are also shown to exist in shock loaded rear-supported granular slugs: these experiments and calculations are used to infer the velocity that free-standing slugs need to acquire to initiate instabilities on their front surfaces. The results presented here, while in an idealised one-dimensional setting, provide physical understanding of the conditions required to

  6. Human footprint variation while performing load bearing tasks.

    Directory of Open Access Journals (Sweden)

    Cara M Wall-Scheffler

    Full Text Available Human footprint fossils have provided essential evidence about the evolution of human bipedalism as well as the social dynamics of the footprint makers, including estimates of speed, sex and group composition. Generally such estimates are made by comparing footprint evidence with modern controls; however, previous studies have not accounted for the variation in footprint dimensions coming from load bearing activities. It is likely that a portion of the hominins who created these fossil footprints were carrying a significant load, such as offspring or foraging loads, which caused variation in the footprint which could extend to variation in any estimations concerning the footprint's maker. To identify significant variation in footprints due to load-bearing tasks, we had participants (N = 30, 15 males and 15 females walk at a series of speeds carrying a 20kg pack on their back, side and front. Paint was applied to the bare feet of each participant to create footprints that were compared in terms of foot length, foot width and foot area. Female foot length and width increased during multiple loaded conditions. An appreciation of footprint variability associated with carrying loads adds an additional layer to our understanding of the behavior and morphology of extinct hominin populations.

  7. Effect of surfaces similarity on contact resistance of fractal rough surfaces under cyclic loading

    Science.gov (United States)

    Gao, Yuanwen; Liu, Limei; Ta, Wurui; Song, Jihua

    2018-03-01

    Although numerous studies have shown that contact resistance depends significantly on roughness and fractal dimension, it remains elusive how they affect contact resistance between rough surfaces. The interface similarity index is first proposed to describe the similarity of the contact surfaces, which gives a good indication of the actual contact area between surfaces. We reveal that the surfaces' similarity be an origin of contact resistance variation. The cyclic loading can increase the contact stiffness, and the contact stiffness increases with the increase of the interface similarity index. These findings explain the mechanism of surface roughness and fractal dimension on contact resistance, and also provide reference for the reliability design of the electrical connection.

  8. Mass loading of soil particles on plant surfaces

    International Nuclear Information System (INIS)

    Pinder, J.E. III; McLeod, K.W.

    1989-01-01

    Radionuclide-bearing soil particles on plant surfaces can be ingested and contribute to human dose, but evaluating the potential dose is limited by the relatively few data available on the masses of soil particles present on plant surfaces. This report summarizes mass loading data (i.e., mass of soil per unit of vegetation) for crops in the southeastern United States and compares these data to (1) those from other regions and (2) the mass loadings used in radionuclide transfer models to predict soil contamination of plant surfaces. Mass loadings were estimated using the 238Pu content of crops as an indicator of soil on plant surfaces. Crops were grown in two soils: a sandy clay loam soil and a loamy sand soil. Concentrations of soil on southeastern crops (i.e., mg soil g-1 plant) differed by more than a factor of 100 due to differences in crop growth form and biomass. Mean concentrations ranged from 1.7 mg g-1 for corn to 260 mg g-1 for lettuce. Differences in mass loadings between soils were less than those among crops. Concentrations differed by less than a factor of two between the two soil types. Because of (1) the differences among crops and (2) the limited data available from other systems, it is difficult to draw conclusions regarding regional or climatic variation in mass loadings. There is, however, little evidence to suggest large differences among regions. The mass loadings used to predict soil contamination in current radionuclide transfer models appear to be less than those observed for most crops

  9. Variation of surface dose in CT

    International Nuclear Information System (INIS)

    Aviles Lucas, P.; Castellano, I. A.; Dance, D. R.; Vano Carruana, E.; Prieto Martin, C.

    2003-01-01

    An experimental study has been made of the variations of the air kerma-length product at the surface of a phantom exposed in a CT scanner using clinical parameters. the effect of patient size, position within the gantry plane and beam-shaping filter type was studied using three different elliptical phantoms. A dose reduction technique based on a sinusoidal tube current modulation system was also investigated. the result of the variation of the surface dose was analysed for the case of CT fluoroscopy procedures. The surface air kerma-length product was shown to be independent of phantom size (within experimental error) but decreases as the surface moves vertically away from the iso centre. The major contributor to this variation the beam-shaping filter. The possibility of underestimating the surface dose if an AAPM body phantom is used (a 36% increase for the head phantom) is an indirect result of the previous conclusion when applied to CT fluoroscopy. This highlights the importance of considering the size and position of the patient when measuring the does. Finally, when the tube current modulation system was used, the maximum surface dose reduction was 18%. (Author) 23 refs

  10. Monotonic Loading of Circular Surface Footings on Clay

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Barari, Amin

    2011-01-01

    Appropriate modeling of offshore foundations under monotonic loading is a significant challenge in geotechnical engineering. This paper reports experimental and numerical analyses, specifically investigating the response of circular surface footings during monotonic loading and elastoplastic beha...

  11. Variational mesh segmentation via quadric surface fitting

    KAUST Repository

    Yan, Dongming

    2012-11-01

    We present a new variational method for mesh segmentation by fitting quadric surfaces. Each component of the resulting segmentation is represented by a general quadric surface (including plane as a special case). A novel energy function is defined to evaluate the quality of the segmentation, which combines both L2 and L2 ,1 metrics from a triangle to a quadric surface. The Lloyd iteration is used to minimize the energy function, which repeatedly interleaves between mesh partition and quadric surface fitting. We also integrate feature-based and simplification-based techniques in the segmentation framework, which greatly improve the performance. The advantages of our algorithm are demonstrated by comparing with the state-of-the-art methods. © 2012 Elsevier Ltd. All rights reserved.

  12. Rock discontinuity surface roughness variation with scale

    Science.gov (United States)

    Bitenc, Maja; Kieffer, D. Scott; Khoshelham, Kourosh

    2017-04-01

    hypothesize that roughness can increase or decrease with the joint size, depending on the large scale roughness (or waviness), which is entering the roughness calculation once the discontinuity size increases. Therefore, our objective is to characterize roughness at various spatial scales, rather than at changing surface size. Firstly, the rock surface is interpolated into a grid on which a Discrete Wavelet Transform (DWT) is applied. The resulting surface components have different frequencies, or in other words, they have a certain physical scale depending on the decomposition level and input grid resolution. Secondly, the Grasselli Parameter is computed for the original and each decomposed surface. Finally, the relative roughness change is analyzed with respect to increasing roughness wavelength for four different rock samples. The scale variation depends on the sample itself and thus indicates its potential mechanical behavior. References: - Barton, N. and V. Choubey (1977). "The shear strength of rock joints in theory and practice." Rock Mechanics and Rock Engineering 10(1): 1-54. - Grasselli, G. (2001). Shear strength of rock joints based on quantified surface description. École Polytechnique Fédérale de Lausanne. Lausanne, EPFL. - Tatone, B. S. A. and G. Grasselli (2009). "A method to evaluate the three-dimensional roughness of fracture surfaces in brittle geomaterials." Review of Scientific Instruments 80(12) - Tatone, B. and G. Grasselli (2012). "An Investigation of Discontinuity Roughness Scale Dependency Using High-Resolution Surface Measurements." Rock Mechanics and Rock Engineering: 1-25.

  13. Variation Of Soil Bearing Capacity with Dynamic Loads (Earthquake Acceleration): Some Examples From Istanbul

    International Nuclear Information System (INIS)

    Ozcep, F.

    2007-01-01

    The static bearing capacity of soils has been extensively studied and reported in literature. However, soils can be subjected to dynamic loads that may be in vertical or horizontal directions Earthquake damage are controlled basically by tree interacting factor groups; earthquake source and path characteristics (1), local geophysical and geotechnical site conditions (2) and structural design and construction features (3). Variation of soil bearing capacity with dynamic loads, i.e. acceleration is one of the most important factor the buildings of structural design that effected dynamic loads. In this study, our aim is to investigate Variation of soil bearing capacity with dynamic loads, i.e. acceleration in some sites of Istanbul city (namely, Avcilar, Buyukcekmece, Kucuk Cekmece, Bahcelievler and Gurpinar). For this aim, some geophysical and geotechnical (boring and laboratory) data were obtained from some geophysical/geotechnical firms and all of these data were used to solve these problems. All calculations of our study were made by Surface Geophysics Analyze , Ms Excell based computer program

  14. The effect of loading rate on ductile fracture toughness and fracture surface roughness

    DEFF Research Database (Denmark)

    Osovski, S.; Srivastava, Akhilesh Kumar; Ponson, L.

    2015-01-01

    The variation of ductile crack growth resistance and fracture surface roughness with loading rate is modeled under mode I plane strain, small scale yielding conditions. Three-dimensional calculations are carried out using an elastic-viscoplastic constitutive relation for a progressively cavitatin...

  15. Variation of surface electric field during geomagnetic disturbed ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 124; Issue 8. Variation of surface electric field ... Diurnal variation of surface electric field measured at Maitri shows a similar variation with worldwide thunderstorm activity, whereas the departure of the field is observed during disturbed periods. This part of the field ...

  16. Surface and Internal Waves due to a Moving Load on a Very Large Floating Structure

    Directory of Open Access Journals (Sweden)

    Taro Kakinuma

    2012-01-01

    Full Text Available Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.

  17. Virtual Polar Motion and Universal Time Variations in Space Geodetic Techniques due to Atmospheric Pressure Loading

    Science.gov (United States)

    Mendes Cerveira, P. J.; Englich, S.; Boehm, J.; Weber, R.; Schuh, H.

    2006-12-01

    Earth rotation variations, in polar motion and universal time (ERP), appear as a response due to the sum of solid Earth displacements, fluid and gaseous mass transports. In finite networks, e.g., the network of eleven operational VLBI stations during the CONT05 VLBI experiment, horizontal displacements due to atmospheric pressure loading (APL) may accidentally introduce a net rotation. Generally, a no-net-rotation is expected, hypothesizing a surface normal stress due to APL upon a radially symmetric Earth. However, the horizontal crustal deformations due to APL given on a 2.5x2.5 degrees grid provided by the Goddard VLBI Group show systematic temporal net rotations. We compared the change of the eleven station network of CONT05 with and without APL, every six hours, by a three Helmert parameter transformation (three rotations). The "virtual" predicted ERP variations were validated w.r.t. the estimated ones, obtained from CONT05 (using the OCCAM 61E VLBI software). These tiny ERP variations, representing about 2 mm on Earth's surface, could statistically be detected if more VLBI sessions were processed. Even the inverted and non-inverted barometric assumptions of the response of the oceans to atmospheric pressure variations could potentially be verified.

  18. Effect of Ingredient Loading on Surface Migration Kinetics of Additives in Vulcanized Natural Rubber Compounds

    Directory of Open Access Journals (Sweden)

    Bryan B. Pajarito

    2014-12-01

    Full Text Available Surface migration kinetics of chemical additives in vulcanized natural rubber compounds were studied as function of ingredient loading. Rubber sheets were compounded according to a 212-8 fractional factorial design of experiment, where ingredients were treated as factors varied at two levels of loading. Amount of migrated additives in surface of rubber sheets was monitored through time at ambient conditions. The maximum amount and estimated rate of additive migration were determined from weight loss kinetic curves. Attenuated total reflection–Fourier transform infrared (ATR-FTIR spectroscopy and optical microscopy were used to characterize the chemical structure and surface morphology of sheet specimens during additive migration. ANOVA results showed that increased loading of reclaimed rubber, CaCO3, and paraffin wax signif icantly decreased the maximum amount of additive migration; by contrast, increased loading of used oil, asphalt, and mercaptobenzothiazole disulphide (MBTS increased the maximum amount. Increased loading of sulfur, diphenylguanidine (DPG, and paraffin wax significantly decreased the additive migration rate; increased loading of used oil, asphalt, and stearic acid elicited an opposite effect. Comparison of ATRFTIR spectra of migrated and cleaned rubber surfaces showed signif icant variation in intensity of specif ic absorbance bands that are also present in infrared spectra of migrating chemicals. Paraffin wax, used oil, stearic acid, MBTS, asphalt, and zinc stearate were identified to bloom and bleed in the rubber sheets. Optical micrographs of migrated rubber surfaces revealed formation of white precipitates due to blooming and of semi-transparent wet patches due to bleeding.

  19. Loading and plotting of cortical surface representations in Nilearn

    Directory of Open Access Journals (Sweden)

    Julia Huntenburg

    2017-02-01

    Full Text Available Processing neuroimaging data on the cortical surface traditionally requires dedicated heavy-weight software suites. Here, we present an initial support of cortical surfaces in Python within the neuroimaging data processing toolbox Nilearn. We provide loading and plotting functions for different surface data formats with minimal dependencies, along with examples of their application. Limitations of the current implementation and potential next steps are discussed.

  20. Surface heat loads on the ITER divertor vertical targets

    Czech Academy of Sciences Publication Activity Database

    Gunn, J. P.; Carpentier-Chouchana, S.; Escourbiac, F.; Hirai, T.; Panayotis, S.; Pitts, R.A.; Corre, Y.; Dejarnac, Renaud; Firdaouss, M.; Kočan, M.; Komm, Michael; Kukushkin, A.; Languille, P.; Missirlian, M.; Zhao, W.; Zhong, G.

    2017-01-01

    Roč. 57, č. 4 (2017), č. článku 046025. ISSN 0029-5515 Institutional support: RVO:61389021 Keywords : ITER * divertor * ELM heat load * inter-ELM heat load * tungsten Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.307, year: 2016 http://iopscience.iop.org/article/10.1088/1741-4326/aa5e2a

  1. A METHOD OF LOADING UNIT FORMATION TAKING INTO ACCOUNT MASS, LOAD-BEARING STRENGTH AND SURFACES OF PACKING UNITS

    Directory of Open Access Journals (Sweden)

    Kamil POPIELA

    2017-09-01

    Full Text Available The problem of loading unit formation is computationally complex in nature. This article presents a heuristic algorithm of forming unit loads, which can be applied to unit load arrangement on unit load devices. This method accounts for dimensional, mass and load-bearing strength of loading units and loading devices. Moreover, the rotation of packages about a 90° vertical axis has been made possible. In this algorithm, the bearing surface of each packing unit is entirely supported. This guarantees the stability of additional unit load layers. A sample calculation of the arrangement of 30-unit loads is presented in this article.

  2. Organic nanofiber-loaded surface plasmon-polariton waveguides

    DEFF Research Database (Denmark)

    Radko, Ilya; Fiutowski, Jacek; Tavares, Luciana

    2011-01-01

    We demonstrate the use of organic nanofibers, composed of self-assembled organic molecules, as a dielectric medium for dielectric-loaded surface plasmon polariton waveguides at near-infrared wavelengths. We successfully exploit a metallic grating coupler to excite the waveguiding mode and charact...

  3. On the influence of moisture and load variations on the strength behavior of wood

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2005-01-01

    Abstract: It is demonstrated in this paper that the influence of moisture- and load variations on lifetime and residual strength (re-cycle strength) of wood can be considered by theories previously developed by the author. The common, controlling factor is creep, which can be modified very easily...... irrespective of loading modes and moisture conditions. Reliability studies may become more ‘reliable’ as the result of recognizing property distributions to be related. Keywords: Moisture variation, load variation, Power-Law creep, lifetime, fatigue, residual strength (re-cycle strength)....

  4. an investigation into the applicability of natural load variation ...

    African Journals Online (AJOL)

    Rev. Anoliefo

    Currently, photvoltaic (PV) modules are characterized based on open circuit voltage, short circuit current as well as voltage and current at ... By looping through the resistors in parallel, the firmware matches load impedance to the impedance of the ..... while series resistance tended to decrease with decrease in irradiance.

  5. Surface Wave Velocity-Stress Relationship in Uniaxially Loaded Concrete

    DEFF Research Database (Denmark)

    Shokouhi, Parisa; Zoëga, Andreas; Wiggenhauser, Herbert

    2012-01-01

    loading cycles revealed that the velocities show a stress-memory effect in good agreement with the Kaiser effect. Comparing the velocities measured during loading and unloading, the effects of stress and damage on the measured velocities could be differentiated. Moreover, the stress dependency of surface......The sonic surface wave (or Rayleigh wave) velocity measured on prismatic concrete specimens under uniaxial compression was found to be highly stress-dependent. At low stress levels, the acoustoelastic effect and the closure of existing microcracks results in a gradual increase in surface wave...... velocities. At higher stress levels, concrete suffers irrecoverable damage: the existing microcracks widen and coalesce and new microcracks form. This progressive damage process leads first to the flattening and eventually the drop in the velocity-stress curves. Measurements on specimens undergoing several...

  6. Experimental Method for Measuring Dust Load on Surfaces in Rooms

    DEFF Research Database (Denmark)

    Lengweiler, Philip; Nielsen, Peter V.; Moser, Alfred

    , there is a need for better understanding of the mechanism of dust deposition and resuspension. With the presented experimental setup, the dust load on surfaces in a channel can be measured as a function of the environmental and surface conditions and the type of particles under controlled laboratory conditions.......A new experimental setup to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust-related problems in rooms...

  7. Tailoring hydrogel surface properties to modulate cellular response to shear loading.

    Science.gov (United States)

    Meinert, Christoph; Schrobback, Karsten; Levett, Peter A; Lutton, Cameron; Sah, Robert L; Klein, Travis J

    2017-04-01

    Biological tissues at articulating surfaces, such as articular cartilage, typically have remarkable low-friction properties that limit tissue shear during movement. However, these frictional properties change with trauma, aging, and disease, resulting in an altered mechanical state within the tissues. Yet, it remains unclear how these surface changes affect the behaviour of embedded cells when the tissue is mechanically loaded. Here, we developed a cytocompatible, bilayered hydrogel system that permits control of surface frictional properties without affecting other bulk physicochemical characteristics such as compressive modulus, mass swelling ratio, and water content. This hydrogel system was applied to investigate the effect of variations in surface friction on the biological response of human articular chondrocytes to shear loading. Shear strain in these hydrogels during dynamic shear loading was significantly higher in high-friction hydrogels than in low-friction hydrogels. Chondrogenesis was promoted following dynamic shear stimulation in chondrocyte-encapsulated low-friction hydrogel constructs, whereas matrix synthesis was impaired in high-friction constructs, which instead exhibited increased catabolism. Our findings demonstrate that the surface friction of tissue-engineered cartilage may act as a potent regulator of cellular homeostasis by governing the magnitude of shear deformation during mechanical loading, suggesting a similar relationship may also exist for native articular cartilage. Excessive mechanical loading is believed to be a major risk factor inducing pathogenesis of articular cartilage and other load-bearing tissues. Yet, the mechanisms leading to increased transmission of mechanical stimuli to cells embedded in the tissue remain largely unexplored. Here, we demonstrate that the tribological properties of loadbearing tissues regulate cellular behaviour by governing the magnitude of mechanical deformation arising from physiological tissue

  8. Diversification of fuel costs accounting for load variation

    International Nuclear Information System (INIS)

    Ruangpattana, Suriya; Preckel, Paul V.; Gotham, Douglas J.; Muthuraman, Kumar; Velástegui, Marco; Morin, Thomas L.; Uhan, Nelson A.

    2012-01-01

    A practical mathematical programming model for the strategic fuel diversification problem is presented. The model is designed to consider the tradeoffs between the expected costs of investments in capacity, operating and maintenance costs, average fuel costs, and the variability of fuel costs. In addition, the model is designed to take the load curve into account at a high degree of resolution, while keeping the computational burden at a practical level. The model is illustrated with a case study for Indiana's power generation system. The model reveals that an effective means of reducing the volatility of the system-level fuel costs is through the reduction of dependence on coal-fired generation with an attendant shift towards nuclear generation. Model results indicate that about a 25% reduction in the standard deviation of the generation costs can be achieved with about a 20–25% increase in average fuel costs. Scenarios that incorporate costs for carbon dioxide emissions or a moratorium on nuclear capacity additions are also presented. Highlights: ► We propose a fuel price risk management model for generation investments accounting for load shape. ► The formulation incorporates a highly refined load curve while maintaining tractability. ► We demonstrate the model for planning generation investments in the state of Indiana for 2025. ► Scenarios reflect charges for CO 2 emissions and a moratorium on new nuclear power.

  9. Spatial and temporal variation in cadmium body loads of four ...

    African Journals Online (AJOL)

    Two-way analysis of variance indicated that spatial (location) rather than temporal (seasonal) factors affected Cd concentrations in the invertebrates. Cd concentrations in False Bay sometimes exceeded the norms or water quality standards. Key words: Cd, invertebrate body burdens, marine pollution, seasonal variations.

  10. On the influence of load variations on lifetime and strength of wood

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2006-01-01

    materials behavior of wood cannot be ‘covered or replaced’ by purely mathematical handling of problems without loss of credibility. Some examples are considered in this note, which cannot be solved following present recommendations: - The influence of load variations on lifetime. - The influence of load...

  11. Deterministic prediction of surface wind speed variations

    Directory of Open Access Journals (Sweden)

    G. V. Drisya

    2014-11-01

    Full Text Available Accurate prediction of wind speed is an important aspect of various tasks related to wind energy management such as wind turbine predictive control and wind power scheduling. The most typical characteristic of wind speed data is its persistent temporal variations. Most of the techniques reported in the literature for prediction of wind speed and power are based on statistical methods or probabilistic distribution of wind speed data. In this paper we demonstrate that deterministic forecasting methods can make accurate short-term predictions of wind speed using past data, at locations where the wind dynamics exhibit chaotic behaviour. The predictions are remarkably accurate up to 1 h with a normalised RMSE (root mean square error of less than 0.02 and reasonably accurate up to 3 h with an error of less than 0.06. Repeated application of these methods at 234 different geographical locations for predicting wind speeds at 30-day intervals for 3 years reveals that the accuracy of prediction is more or less the same across all locations and time periods. Comparison of the results with f-ARIMA model predictions shows that the deterministic models with suitable parameters are capable of returning improved prediction accuracy and capturing the dynamical variations of the actual time series more faithfully. These methods are simple and computationally efficient and require only records of past data for making short-term wind speed forecasts within practically tolerable margin of errors.

  12. Normal loads program for aerodynamic lifting surface theory. [evaluation of spanwise and chordwise loading distributions

    Science.gov (United States)

    Medan, R. T.; Ray, K. S.

    1974-01-01

    A description of and users manual are presented for a U.S.A. FORTRAN 4 computer program which evaluates spanwise and chordwise loading distributions, lift coefficient, pitching moment coefficient, and other stability derivatives for thin wings in linearized, steady, subsonic flow. The program is based on a kernel function method lifting surface theory and is applicable to a large class of planforms including asymmetrical ones and ones with mixed straight and curved edges.

  13. Global color variations on the Martian surface

    Science.gov (United States)

    Soderblom, L.A.; Edwards, K.; Eliason, E.M.; Sanchez, E.M.; Charette, M.P.

    1978-01-01

    Surface materials exposed throughout the equatorial region of Mars have been classified and mapped on the basis of spectral reflectance properties determined by the Viking II Orbiter vidicon cameras. Frames acquired at each of three wavelengths (0.45 ?? 0.03 ??m, 0.53 ?? 0.05 ??m, and 0.59 ?? 0.05 ??m) during the approach of Viking Orbiter II in Martian summer (Ls = 105??) were mosaicked by computer. The mosaics cover latitudes 30??N to 63??S for 360?? of longitude and have resolutions between 10 and 20 km per line pair. Image processing included Mercator transformation and removal of an average Martian photometric function to produce albedo maps at three wavelengths. The classical dark region between the equator and ???30??S in the Martian highlands is composed of two units: (i) and ancient unit consisting of topographic highs (ridges, crater rims, and rugged plateaus riddled with small dendritic channels) which is among the reddest on the planet (0.59/0.45 ??m {reversed tilde equals} 3); and (ii) intermediate age, smooth, intercrater volcanic plains displaying numerous mare ridges which are among the least red on Mars (0.59/0.45 ??m {reversed tilde equals} 2). The relatively young shield volcanoes are, like the oldest unit, dark and very red. Two probable eolian deposits are recognized in the intermediate and high albedo regions. The stratigraphically lower unit is intermediate in both color (0.59/ 0.45 ??m {reversed tilde equals} 2.5) and albedo. The upper unit has the highest albedo, is very red (0.59/0.45 ??m {reversed tilde equals} 3), and is apparently the major constituent of the annual dust storms as its areal extent changes from year to year. The south polar ice cap and condensate clouds dominate the southernmost part of the mosaics. ?? 1978.

  14. THE EFFECT OF VARIATION CONCRETE CUBE OF AXIAL LOAD ON ULTRASONIC PULSE VELOCITY TRANSMITTER

    Directory of Open Access Journals (Sweden)

    Faqih Ma’arif

    2015-05-01

    The test result showed that the increase of ultrasonic pulse velocity effect on cube II due to axial load variation was optimum at 0,35P0 and was minimum at 0,7P0, if compared to the one without axial load, the results were 4,17% and 11,60 respectively. The decrease of pulse velocity on cube III due to axial load variation was at 0,25P0 and 0,7P0; if compared to the one without axial load the result were 0,47% and 20,87% respectively. And the increase of ultrasonic pulse velocity effect on cube IV due to axial load variation was optimum at 0,35P0 and was minimum at 0,7P0; if compared to the one without axial load the result were 0,52% and 21,63% respectively. The maximum limit of effective load step at structure experiencing compressive load ranged from 0,35P0 up to 0,4P0. At high stress level, the crack that occurred was spread evenly to the concrete cubic components and was giving an exponential equation y = y= 5,11e0,0467x. The result of analysis of cubes II, III and IV showed that on paired sample t-test 0,00<0,025, the significant value (2-tailed (0,00<(0,025; meaning there was a difference of pulse velocity due to axial load variation on concrete cube.

  15. Experiments on Growth and Variation of Spaceship Loaded Plant Seeds

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S. Y.; Lee, G. J.; Kim, D. S.; Kim, J. B.

    2008-08-15

    This educational experiment was designed (1)to obtain the basic information on the effects of the space environments on plant growth and mutagenesis, (2)to evaluate plant germination and seedling growth under the effect of microgravity and light conditions and (3)to improve a child's scientific mind through the real-time observations of a seedling growth for two plants conducted both in space and on earth. This project was implemented?as one of the missions in the Korean Astronaut Program. Seeds of eleven plant species (rice, soybean, rape, radish, hot pepper, perilla, arabidopsis, orchids, dandelion, hibiscus, cosmos) was vacuum-sealed in aluminium bags. Those seeds was loaded in the 'Progress' spaceship in Feb. 2008, traveled in the 'Progress', placed in the Russian Sector-International Space Station (RS-ISS), and then was brought by the Korean astronaut from the RS-ISS, and handed over to us at Korea Atomic Energy Research Institute(KAERI). The germination rate, plant growth and mutation type/frequency of the returned plants are under testing in the lab and field in KAERI now. The first Korean astronaut, Dr. So-Yeon Yi, who had returned to earth on April 19, 2008 after successfully completing her scientific mission for 12 days in Space, performed the experiment of plant germination and seedling growth in the International Space Station (ISS), and a similarly designed experiment kit was distributed to conduct the experiment by student and adult volunteers in Korea at the same time. The experiment was to observe the effects of microgravity and light on a seedling growth for soybean and radish. We designed a growth kit that was an all-in-one package consisting of seeds (12 seeds in each chamber) and rock wool as a growing medium filled in four polycarbonate growing chambers in a light proof textile bag or carton paper. The bottom of the chamber was filled with a tightly-fitted rock wool which can hold water and provide moisture during a

  16. Experiments on Growth and Variation of Spaceship Loaded Plant Seeds

    International Nuclear Information System (INIS)

    Kang, S. Y.; Lee, G. J.; Kim, D. S.; Kim, J. B.

    2008-08-01

    This educational experiment was designed (1)to obtain the basic information on the effects of the space environments on plant growth and mutagenesis, (2)to evaluate plant germination and seedling growth under the effect of microgravity and light conditions and (3)to improve a child's scientific mind through the real-time observations of a seedling growth for two plants conducted both in space and on earth. This project was implemented?as one of the missions in the Korean Astronaut Program. Seeds of eleven plant species (rice, soybean, rape, radish, hot pepper, perilla, arabidopsis, orchids, dandelion, hibiscus, cosmos) was vacuum-sealed in aluminium bags. Those seeds was loaded in the 'Progress' spaceship in Feb. 2008, traveled in the 'Progress', placed in the Russian Sector-International Space Station (RS-ISS), and then was brought by the Korean astronaut from the RS-ISS, and handed over to us at Korea Atomic Energy Research Institute(KAERI). The germination rate, plant growth and mutation type/frequency of the returned plants are under testing in the lab and field in KAERI now. The first Korean astronaut, Dr. So-Yeon Yi, who had returned to earth on April 19, 2008 after successfully completing her scientific mission for 12 days in Space, performed the experiment of plant germination and seedling growth in the International Space Station (ISS), and a similarly designed experiment kit was distributed to conduct the experiment by student and adult volunteers in Korea at the same time. The experiment was to observe the effects of microgravity and light on a seedling growth for soybean and radish. We designed a growth kit that was an all-in-one package consisting of seeds (12 seeds in each chamber) and rock wool as a growing medium filled in four polycarbonate growing chambers in a light proof textile bag or carton paper. The bottom of the chamber was filled with a tightly-fitted rock wool which can hold water and provide moisture during a seedling growth. The

  17. Reactive solid surface morphology variation via ionic diffusion.

    Science.gov (United States)

    Sun, Zhenchao; Zhou, Qiang; Fan, Liang-Shih

    2012-08-14

    In gas-solid reactions, one of the most important factors that determine the overall reaction rate is the solid morphology, which can be characterized by a combination of smooth, convex and concave structures. Generally, the solid surface structure varies in the course of reactions, which is classically noted as being attributed to one or more of the following three mechanisms: mechanical interaction, molar volume change, and sintering. Here we show that if a gas-solid reaction involves the outward ionic diffusion of a solid-phase reactant then this outward ionic diffusion could eventually smooth the surface with an initial concave and/or convex structure. Specifically, the concave surface is filled via a larger outward diffusing surface pointing to the concave valley, whereas the height of the convex surface decreases via a lower outward diffusion flux in the vertical direction. A quantitative 2-D continuum diffusion model is established to analyze these two morphological variation processes, which shows consistent results with the experiments. This surface morphology variation by solid-phase ionic diffusion serves to provide a fourth mechanism that supplements the traditionally acknowledged solid morphology variation or, in general, porosity variation mechanisms in gas-solid reactions.

  18. Variations of Ship’s Deck Elevation Due to Stochastic Process of Containers Loading

    Directory of Open Access Journals (Sweden)

    Przemyslaw Krata

    2015-12-01

    Full Text Available The stochastic process of container loading is described in the paper with special emphasis to ship motion when she is lying at a quay. The 3 DOF system was applied to describe rolling, pitching and heaving of a vessel which may cause a significant variations of momentary deck elevation. The realistic range of such variations are assessed for a variety of cargo locations on-board and a phase shift between two independent gantries engaged in cargo operations. The process is modeled with regard to random character of crucial variables affecting ship motion due to cargo loading.

  19. effects of load and speed variations in a modified closed loop v/f

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... Abstract. This paper investigates the effects of load and reference speed variations in a modified closed loop v/f induction motor drive. A modified approach, involving the addition of a low frequency boost voltage, is developed and adopted as an enhancement to the conventional closed loop v/f speed.

  20. Effects of Load and Speed Variations in a Modified Closed Loop V/F ...

    African Journals Online (AJOL)

    This paper investigates the eects of load and reference speed variations in a modied closed loopv=f induction motor drive. A modied approach, involving the addition of a low frequency boostvoltage, is developed and adopted as an enhancement to the conventional closed loop v=f speedcontrol of a three phase squirrel ...

  1. Effects of arterial load variations on dynamic arterial elastance: an experimental study.

    Science.gov (United States)

    Monge García, M I; Guijo González, P; Gracia Romero, M; Gil Cano, A; Rhodes, A; Grounds, R M; Cecconi, M

    2017-06-01

    Dynamic arterial elastance (Ea dyn ), the relationship between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a functional assessment of arterial load. The aim of this study was to evaluate the impact of arterial load changes during acute pharmacological changes, fluid administration, and haemorrhage on Ea dyn . Eighteen anaesthetized, mechanically ventilated New Zealand rabbits were studied. Arterial load changes were induced by phenylephrine ( n =9) or nitroprusside ( n =9). Thereafter, animals received a fluid bolus (10 ml kg -1 ), followed by stepwise bleeding (blood loss: 15 ml kg -1 ). The influence of arterial load and cardiac variables on PPV, SVV, and Ea dyn was analysed using a linear mixed-effects model analysis. After phenylephrine infusion, mean ( sd ) Ea dyn decreased from 0.89 (0.14) to 0.49 (0.12), P load induced significant changes on Ea dyn ; vasodilatation increased Ea dyn , whereas vasoconstriction decreased it. The Ea dyn was associated with both arterial load and cardiac factors, suggesting that Ea dyn should be more properly considered as a ventriculo-arterial coupling index. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  2. Surface modification of titanium for load-bearing applications.

    Science.gov (United States)

    Bose, Susmita; Roy, Mangal; Das, Kakoli; Bandyopadhyay, Amit

    2009-12-01

    Titanium and its alloys are extensively used in load-bearing metallic devices. They are bioinert material and, therefore, get encapsulated after implantation into the living body by a fibrous tissue that isolates them from the surrounding tissues. Here we report modification of titanium surface using bioactive tricalcium phosphates (TCP) and nanoscale TiO2 to enhance cell-materials interaction. We have introduced bioactivity in Ti using laser-assisted coating of TCP and by anodization to grow surface TiO2 at room temperature using a mixed aqueous solution of sodium fluoride, citric acid and sulfuric acid as electrolyte. TCP coating showed a columnar Ti grains at the substrate side of the coating and transitioned to an equiaxed grains at the outside. Coating hardness increased from 882 +/- 67 to 1029 +/- 112 Hv as the volume fraction of TCP increased in the coating. For TiO2 nanotubes, microscopic analysis showed tubes of 50 nm in diameter with wall thickness of 15 nm and typical length between 200 nm and 1 micron based on anodization times. Effects of TCP and nanoscale TiO2 coating on bone cell-material interaction were examined by culturing osteoprecursor cells (OPC1) on coated surfaces. Antibacterial activity analysis using metallic Ag via electrodeposition showed over 99% antibacterial activity against the growth of colonies of Pseudomonas aeruginosa.

  3. Load-velocity relationship in variations of the half-squat exercise: Influence of execution technique.

    Science.gov (United States)

    Pérez-Castilla, Alejandro; García-Ramos, Amador; Padial, Paulino; Morales-Artacho, Antonio J; Feriche, Belén

    2017-09-06

    Previous studies have revealed that the velocity of the bar can be used to determine the intensity of different resistance training exercises. However, the load-velocity relationship seems to be exercise dependent. This study aimed to compare the load-velocity relationship obtained from two variations of the half-squat exercise (traditional vs. ballistic) using two execution techniques (eccentric-concentric vs. concentric-only). Twenty men performed a submaximal progressive loading test in four half-squat exercises: eccentric-concentric traditional-squat, concentric-only traditional-squat, countermovement jump (i.e. ballistic squat using the eccentric-concentric technique), and squat jump (i.e. ballistic squat using the concentric-only technique). Individual linear regressions were used to estimate the one-repetition maximum (1RM) for each half-squat exercise. Thereafter, another linear regression was applied to establish the relationship between relative load (%RM) and mean propulsive velocity (MPV). For all exercises, a strong relationship was observed between %RM and MPV: eccentric-concentric traditional-squat (R = 0.949), concentric-only traditional-squat (R = 0.920), countermovement jump (R = 0.957), and squat jump (R = 0.879). The velocities associated with each %RM were higher for the ballistic variation and the eccentric-concentric technique than for the traditional variation and concentric-only technique, respectively. Differences in velocity among the half-squat exercises decreased with the increment in the relative load. These results demonstrate that the MPV can be used to predict exercise intensity in the four half-squat exercises. However, independent regressions are required for each half-squat exercise since the load-velocity relationship proved to be task specific.

  4. Variation in buccal surface morphology of deciduous first molars.

    Science.gov (United States)

    Simratvir, M; Moghe, G; Singh, D; Dhillon, K

    2012-01-01

    The buccal bulge of the deciduous first molars has always been a restorative challenge to the pediatric dentist. Morphologically it may vary from a slight prominence to a well-developed cusp-like structure. This study was conducted to determine the variable buccal surface morphology of deciduous first molar and its clinical relevance. A prospective study was conducted whereby 2016 patients visiting the outpatient clinic of dental hospital over 1 year were evaluated. Any variation in buccal surface morphology of the deciduous first molars was recorded photographically or by replicating in dental stone. Varied morphological patterns on buccal surface were observed for which a new classification scheme has been proposed. The surface morphology of deciduous teeth crowns must be studied carefully as it may be indicative of pulpal extensions and accessory roots, requiring consideration during restorative treatment planning.

  5. Diurnal and seasonal variations of surface water vapour density ...

    African Journals Online (AJOL)

    Diurnal and seasonal variations of surface water vapour density over some meteorological stations in Nigeria. ... Ife Journal of Science ... the three Sahelian stations, was 5.29±0.39; while during the rainy season, they were 21.72±1.22, 19.60±0.12 and 19.47±0.07 for the Southern, Midland and Northern regions respectively.

  6. Landscape variation in tree regeneration and snag fall drive fuel loads in 24-year old post-fire lodgepole pine forests.

    Science.gov (United States)

    Nelson, Kellen N; Turner, Monica G; Romme, William H; Tinker, Daniel B

    2016-12-01

    Escalating wildfire in subalpine forests with stand-replacing fire regimes is increasing the extent of early-seral forests throughout the western USA. Post-fire succession generates the fuel for future fires, but little is known about fuel loads and their variability in young post-fire stands. We sampled fuel profiles in 24-year-old post-fire lodgepole pine (Pinus contorta var. latifolia) stands (n = 82) that regenerated from the 1988 Yellowstone Fires to answer three questions. (1) How do canopy and surface fuel loads vary within and among young lodgepole pine stands? (2) How do canopy and surface fuels vary with pre- and post-fire lodgepole pine stand structure and environmental conditions? (3) How have surface fuels changed between eight and 24 years post-fire? Fuel complexes varied tremendously across the landscape despite having regenerated from the same fires. Available canopy fuel loads and canopy bulk density averaged 8.5 Mg/ha (range 0.0-46.6) and 0.24 kg/m 3 (range: 0.0-2.3), respectively, meeting or exceeding levels in mature lodgepole pine forests. Total surface-fuel loads averaged 123 Mg/ha (range: 43-207), and 88% was in the 1,000-h fuel class. Litter, 1-h, and 10-h surface fuel loads were lower than reported for mature lodgepole pine forests, and 1,000-h fuel loads were similar or greater. Among-plot variation was greater in canopy fuels than surface fuels, and within-plot variation was greater than among-plot variation for nearly all fuels. Post-fire lodgepole pine density was the strongest positive predictor of canopy and fine surface fuel loads. Pre-fire successional stage was the best predictor of 100-h and 1,000-h fuel loads in the post-fire stands and strongly influenced the size and proportion of sound logs (greater when late successional stands had burned) and rotten logs (greater when early successional stands had burned). Our data suggest that 76% of the young post-fire lodgepole pine forests have 1,000-h fuel loads that exceed levels

  7. Impact of the variation in dynamic vehicle load on flexible pavement responses

    Science.gov (United States)

    Ahsanuzzaman, Md

    The purpose of this research was to evaluate the dynamic variation in asphalt pavement critical responses due to dynamic tire load variations. An attempt was also made to develop generalized regression equations to predict the dynamic response variation in flexible pavement under various dynamic load conditions. The study used an extensive database of computed pavement response histories for five different types of sites (smooth, rough, medium rough, very rough and severely rough), two different asphalt pavement structures (thin and thick) at two temperatures (70 °F and 104 °F), subjected to a tandem axle dual tire at three speeds 25, 37 and 50 mph (40, 60 and 80 km/h). All pavement responses were determined using the 3D-Move Analysis program (Version 1.2) developed by University of Nevada, Reno. A new term called Dynamic Response Coefficient (DRC) was introduced in this study to address the variation in critical pavement responses due to dynamic loads as traditionally measured by the Dynamic Load Coefficient (DLC). While DLC represents the additional varying component of the tire load, DRC represents the additional varying component of the response value (standard deviation divided by mean response). In this study, DRC was compared with DLC for five different sites based on the roughness condition of the sites. Previous studies showed that DLC varies with vehicle speed and suspension types, and assumes a constant value for the whole pavement structure (lateral and vertical directions). On the other hand, in this study, DRC was found to be significantly varied with the asphalt pavement and function of pavement structure, road roughness conditions, temperatures, vehicle speeds, suspension types, and locations of the point of interest in the pavement. A major contribution of the study is that the variation of pavement responses due to dynamic load in a flexible pavement system can be predicted with generalized regression equations. Fitting parameters (R2) in the

  8. Variations of surface ozone concentration across the Klang Valley, Malaysia

    Science.gov (United States)

    Latif, Mohd Talib; Huey, Lim Shun; Juneng, Liew

    2012-12-01

    Hourly air quality data covering the period 2004-2008 was obtained from the Air Quality Division, the Department of Environment (DOE) through long-term monitoring by Alam Sekitar Sdn. Bhd. (ASMA) were analysed to investigate the variations of surface ozone (O3) in the Klang Valley, Malaysia. A total of nine monitoring stations were selected for analysis in this study and the results show that there are distinct seasonal patterns in the surface O3 across the Klang Valley. A high surface O3 concentration is usually observed between January and April, while a low surface O3 concentration is found between June and August. Analysis of daily variations in surface O3 and the precursors - NO, NO2, CO, NMHC and UVb, indicate that the surface O3 photochemistry in this study area exhibits a positive response to the intensity and wavelength in UVb while being influenced by the concentration of NOx, particularly through tritration processes. Although results from our study suggested that NMHCs may influence the maximum O3 concentration, further investigation is required. Wind direction during different monsoons was found to influence the concentration of O3 around the Klang Valley. HYSPLIT back trajectories (-72 h) were used to indicate the air-mass transport patterns on days with high concentrations of surface O3 in the study area. Results show that 47% of the high O3 days was associated with the localized circulation. The remaining 32% and 22% were associated with mid-range and long-range transport across the South China Sea from the northeast.

  9. Temporal variation of streamflow, sediment load and their relationship in the Yellow River basin, China.

    Directory of Open Access Journals (Sweden)

    Guangju Zhao

    Full Text Available Variation of streamflow and sediment load in the Yellow River basin has received considerable attention due to its drastic reduction during the past several decades. This paper presents a detailed investigation on the changes of streamflow and sediment load from 1952 to 2011 using monthly observations at four gauging stations along the Yellow River. The results show significant decreasing trends for both streamflow and sediment load at all four gauging stations over the past 60 years. The wavelet transform demonstrated discontinuous periodicities from 1969 to 1973 and after 1986 due to the construction of large reservoirs and implementation of numerous soil and water conservations practices. The sediment rating curves with the power-law function was applied to investigate the relationship between discharge and sediment load. The results indicate distinct variations of the relationship between streamflow and sediment and implied significant hydro-morphological changes within different periods. The reducing sediment supply from the source region and the increased erosive power of the river are detected at Lanzhou station, while the decrease of the transport capacity at Toudaoguai is caused by severe siltation. Significant changes in the relationship between streamflow and sediment load are found at Huayuankou and Gaocun stations, which are largely induced by evident sediment income and trapping effects of large reservoirs. It is estimated that numerous reservoirs have strongly altered the regime and magnitude of streamflow and trapped large amount of sediment, leading to severe siltation and evident reduction of their total volumes. A decrease in precipitation, incoming water from the upper reaches, soil and water conservation measures as well as water consumption contribute most to the significant reduction of streamflow. The decrease of sediment load mainly resulted from various soil and water conservation measures and trapping in reservoirs

  10. Influence of Surface Energy Effects on Elastic Fields of a Layered Elastic Medium under Surface Loading

    Directory of Open Access Journals (Sweden)

    Supakorn Tirapat

    2017-01-01

    Full Text Available This paper presents the analysis of a layered elastic half space under the action of axisymmetric surface loading and the influence of the surface energy effects. The boundary value problems for the bulk and the surface are formulated based on classical linear elasticity and a complete Gurtin-Murdoch constitutive relation. An analytical technique using Love’s representation and the Hankel integral transform is employed to derive an integral-form solution for both displacement and stress fields. An efficient numerical quadrature is then applied to accurately evaluate all involved integrals. Selected numerical results are presented to portray the influence of various parameters on elastic fields. Numerical results indicate that the surface stress displays a significant influence on both displacement and stress fields. It is also found that the layered half space becomes stiffer with the presence of surface stresses. In addition, unlike the classical elasticity solution, size-dependent behavior of elastic fields is noted. The present analytical solutions provide fundamental understanding of the influence of surface energy on layered elastic materials. It can also be used as a benchmark solution for the development of numerical techniques such as FEM and BEM, for analysis of more complex problems involving a layered medium under the influence of surface energy effects.

  11. Surface ultraviolet radiation over east Siberia: seasonal variations

    Directory of Open Access Journals (Sweden)

    A. V. Mikhalev

    Full Text Available The results of spectral measurements of the daily near-noon surface direct solar ultraviolet radiation in the wavelength range of 295–345 nm obtained in Irkutsk (East Siberia for the time interval of 1998–2000 are presented. For the period under consideration, the seasonal UV radiation variations are analysed that are associated with the total ozone dynamics, the transition of cyclonic and anticyclonic (Siberian anticyclone periods, the presence of snow cover, and other factors. The analysis reveals an asymmetric behaviour of the seasonal course in ground-level UV radiation around the time of the summer solstice, with seasonal variation dependence on the wavelength. We have determined the irregular variations of surface UV radiation that is typical for the region, with their properties dependent on the season and on the spectral range analysed. The similarity of the above noted features from year to year was revealed.

    Key words. Atmospheric composition and structure (Transmission and scattering of radiation; instruments and techniques – Meteorology and atmospheric dynamics (middle atmosphere dynamics

  12. Effects of Viscosity Variation and Surface Roughness on the Couple stress Squeeze Film Characteristics of Short Journal Bearings

    Directory of Open Access Journals (Sweden)

    G.H. Ayyappa

    2015-03-01

    Full Text Available The theoretical analysis of the combined effects of surface roughness and viscosity variation on the couple stress squeeze film characteristics of short journal bearings is presented. The modified stochastic Reynold’s equation accounting for the viscosity variation of couple stresses fluid and randomized surface roughness structure on bearing surface is mathematically derived using the Christensen stochastic theory. It is observed that, the transverse roughness pattern improves the squeeze film characteristics whereas the bearing performance is affected due to the presence of one dimensional longitudinal surface roughness. Further, it is observed that, the effect of viscosity variation is to reduce the load carrying capacity and squeeze film time as compared to the case of constant viscosity.

  13. Genetic variation and significance of hepatitis B surface antigen

    Directory of Open Access Journals (Sweden)

    ZHANG Zhenhua

    2013-11-01

    Full Text Available Hepatitis B virus (HBV is prone to genetic variation because there is reverse transcription in the process of HBV replication. The gene mutation of hepatitis B surface antigen may affect clinical diagnosis of HBV infection, viral replication, and vaccine effect. The current research and existing problems are discussed from the following aspects: the mechanism and biological and clinical significance of S gene mutation. Most previous studies focused on S gene alone, so S gene should be considered as part of HBV DNA in the future research on S gene mutation.

  14. Two approaches to form antibacterial surface: Doping with bactericidal element and drug loading

    International Nuclear Information System (INIS)

    Sukhorukova, I.V.; Sheveyko, A.N.; Kiryukhantsev-Korneev, Ph.V.; Anisimova, N.Y.; Gloushankova, N.A.; Zhitnyak, I.Y.; Benesova, J.; Amler, E.; Shtansky, D.V.

    2015-01-01

    Graphical abstract: - Highlights: • Bioactive materials with rate-controlled release of antibacterial agent. • Ag + ion release from TiCaPCON-Ag films depended on Ag content. • TiCaPCON-coated Ti network structure with blind pores loaded with co-amoxiclav. • Strong bactericidal effect of drug-loaded samples. • Antibacterial yet biocompatible and bioactive surfaces. - Abstract: Two approaches (surface doping with bactericidal element and loading of antibiotic into specially formed surface microcontainers) to the fabrication of antibacterial yet biocompatible and bioactive surfaces are described. A network structure with square-shaped blind pores of 2.6 ± 0.6 × 10 −3 mm 3 for drug loading was obtained by selective laser sintering (SLS). The SLS-fabricated samples were loaded with 0.03, 0.3, 2.4, and 4 mg/cm 2 of co-amoxiclav (amoxicillin and clavulanic acid). Ag-doped TiCaPCON films with 0.4, 1.2, and 4.0 at.% of Ag were obtained by co-sputtering of composite TiC 0.5 -Ca 3 (PO 4 ) 2 and metallic Ag targets. The surface structure of SLS-prepared samples and cross-sectional morphology of TiCaPCON-Ag films were studied by scanning electron microscopy. The through-thickness of Ag distribution in the TiCaPCON-Ag films was obtained by glow discharge optical emission spectroscopy. The kinetics of Ag ion release in normal saline solution was studied using inductively coupled plasma mass spectrometry. Bacterial activity of the samples was evaluated against S. epidermidis, S. aureus, and K. pneum. ozaenae using the agar diffusion test and photometric method by controlling the variation of optical density of the bacterial suspension over time. Cytocompatibility of the Ag-doped TiCaPCON films was observed in vitro using chondrocytic and MC3T3-E1 osteoblastic cells. The viability and proliferation of chondrocytic cells were determined using the MTS assay and PicoGreen assay tests, respectively. The alkaline phosphatase (ALP) activity of the SLS-fabricated samples

  15. Two approaches to form antibacterial surface: Doping with bactericidal element and drug loading

    Energy Technology Data Exchange (ETDEWEB)

    Sukhorukova, I.V.; Sheveyko, A.N.; Kiryukhantsev-Korneev, Ph.V. [National University of Science and Technology “MISIS”, Leninsky pr. 4, Moscow 119049 (Russian Federation); Anisimova, N.Y.; Gloushankova, N.A.; Zhitnyak, I.Y. [N.N Blokhin Russian Cancer Research Center of RAMS, Kashirskoe shosse 24, Moscow 115478 (Russian Federation); Benesova, J. [Institute of Experimental Medicine of the ASCR, Vídenska 1083, Prague 14220 (Czech Republic); Institute of Biophysics, 2nd Faculty of Medicine, Charles University in Prague, V Uvalu 84, Prague 15006 (Czech Republic); Amler, E. [Institute of Experimental Medicine of the ASCR, Vídenska 1083, Prague 14220 (Czech Republic); Faculty of Biomedical Engineering, Czech Technical University in Prague (Czech Republic); Shtansky, D.V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky pr. 4, Moscow 119049 (Russian Federation)

    2015-03-01

    Graphical abstract: - Highlights: • Bioactive materials with rate-controlled release of antibacterial agent. • Ag{sup +} ion release from TiCaPCON-Ag films depended on Ag content. • TiCaPCON-coated Ti network structure with blind pores loaded with co-amoxiclav. • Strong bactericidal effect of drug-loaded samples. • Antibacterial yet biocompatible and bioactive surfaces. - Abstract: Two approaches (surface doping with bactericidal element and loading of antibiotic into specially formed surface microcontainers) to the fabrication of antibacterial yet biocompatible and bioactive surfaces are described. A network structure with square-shaped blind pores of 2.6 ± 0.6 × 10{sup −3} mm{sup 3} for drug loading was obtained by selective laser sintering (SLS). The SLS-fabricated samples were loaded with 0.03, 0.3, 2.4, and 4 mg/cm{sup 2} of co-amoxiclav (amoxicillin and clavulanic acid). Ag-doped TiCaPCON films with 0.4, 1.2, and 4.0 at.% of Ag were obtained by co-sputtering of composite TiC{sub 0.5}-Ca{sub 3}(PO{sub 4}){sub 2} and metallic Ag targets. The surface structure of SLS-prepared samples and cross-sectional morphology of TiCaPCON-Ag films were studied by scanning electron microscopy. The through-thickness of Ag distribution in the TiCaPCON-Ag films was obtained by glow discharge optical emission spectroscopy. The kinetics of Ag ion release in normal saline solution was studied using inductively coupled plasma mass spectrometry. Bacterial activity of the samples was evaluated against S. epidermidis, S. aureus, and K. pneum. ozaenae using the agar diffusion test and photometric method by controlling the variation of optical density of the bacterial suspension over time. Cytocompatibility of the Ag-doped TiCaPCON films was observed in vitro using chondrocytic and MC3T3-E1 osteoblastic cells. The viability and proliferation of chondrocytic cells were determined using the MTS assay and PicoGreen assay tests, respectively. The alkaline phosphatase (ALP

  16. EPR: high load variation performances with the 'TMODE' core control

    Energy Technology Data Exchange (ETDEWEB)

    Pairot, Frederic [AREVA NP, Tour AREVA, BAL1739A, 92084 Paris La Defense Cedex (France)

    2008-07-01

    The load variation performances on a PWR are directly linked to the core control design. This design is mainly characterized by the definition of the control rod banks and the way to both perform the banks movements and to modify the core boron concentration by injection of boric acid or water. The following paper presents the principles of the T mode, the new fully automatic core control mode for the EPR which provides high performance in terms of maneuverability and optimizes the effluents. First, the paper describes the division of the control rods into two control banks (Pbank for temperature and Hbank for power distribution). Then typical movements of these banks during power changes are shown. Then, the principle of the 3 control loops (Tave, AO, Pmax), used to obtain these desired control rod movements, is given. Finally, a load following transient simulation is presented. (author)

  17. Sewage-treatment under substantial load variations in winter tourism areas--a full case study.

    Science.gov (United States)

    Winkler, S; Matsché, N; Gamperer, T; Dum, M

    2004-01-01

    The sewage-load variations in winter tourism areas are characterized by sudden increases--in the range of a factor two to three--within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal. A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID-concept, which is a special two stage activated sludge process for extensive nutrient removal.

  18. An Analytic Equation Partitioning Climate Variation and Human Impacts on River Sediment Load

    Science.gov (United States)

    Zhang, J.; Gao, G.; Fu, B.

    2017-12-01

    Spatial or temporal patterns and process-based equations could co-exist in hydrologic model. Yet, existing approaches quantifying the impacts of those variables on river sediment load (RSL) changes are found to be severely limited, and new ways to evaluate the contribution of these variables are thus needed. Actually, the Newtonian modeling is hardly achievable for this process due to the limitation of both observations and knowledge of mechanisms, whereas laws based on the Darwinian approach could provide one component of a developed hydrologic model. Since that streamflow is the carrier of suspended sediment, sediment load changes are documented in changes of streamflow and suspended sediment concentration (SSC) - water discharge relationships. Consequently, an analytic equation for river sediment load changes are proposed to explicitly quantify the relative contributions of climate variation and direct human impacts on river sediment load changes. Initially, the sediment rating curve, which is of great significance in RSL changes analysis, was decomposed as probability distribution of streamflow and the corresponding SSC - water discharge relationships at equally spaced discharge classes. Furthermore, a proposed segmentation algorithm based on the fractal theory was used to decompose RSL changes attributed to these two portions. Additionally, the water balance framework was utilized and the corresponding elastic parameters were calculated. Finally, changes in climate variables (i.e. precipitation and potential evapotranspiration) and direct human impacts on river sediment load could be figured out. By data simulation, the efficiency of the segmentation algorithm was verified. The analytic equation provides a superior Darwinian approach partitioning climate and human impacts on RSL changes, as only data series of precipitation, potential evapotranspiration and SSC - water discharge are demanded.

  19. Multilayered elastic analysis formulation for surface moment loading

    CSIR Research Space (South Africa)

    Maina, JW

    2006-01-01

    Full Text Available , respectively. Measurements by Stress-In-Motion (SIM) technology on slow (creep) speed truck tires have shown that, depending on the magnitude of the load, there are acceptable "n" or unacceptable "m" shaped stress distributions at the tire/road interface...

  20. Modeling seasonal surface temperature variations in secondary tropical dry forests

    Science.gov (United States)

    Cao, Sen; Sanchez-Azofeifa, Arturo

    2017-10-01

    Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15-20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6-8 K warmer than the intermediate successional stages and were 9-10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0-1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.

  1. Distribution and temporal variation of trace metal enrichment in surface sediments of San Jorge Bay, Chile.

    Science.gov (United States)

    Valdés, Jorge; Román, Domingo; Guiñez, Marcos; Rivera, Lidia; Morales, Tatiana; Morales, Tomás; Avila, Juan; Cortés, Pedro

    2010-08-01

    Cu, Pb, and Hg concentrations were determined in surface sediment samples collected at three sites in San Jorge Bay, northern Chile. This study aims to evaluate differences in their spatial distribution and temporal variability. The highest metal concentrations were found at the site "Puerto", where minerals (Cu and Pb) have been loaded for more than 60 years. On the other hand, Hg does not pose a contamination problem in this bay. Cu and Pb concentrations showed significant variations from 1 year to another. These variations seem to be a consequence of the combination of several factors, including changes in the loading and/or storage of minerals in San Jorge Bay, the dredging of bottom sediments (especially at Puerto), and seasonal changes in physical-chemical properties of the water column that modify the exchange of metals at the sediment-water interface. Differences in the contamination factor and geoaccumulation index suggest that pre-industrial concentrations measured in marine sediments of this geographical zone, were better than geological values (average shale, continental crust average) for evaluating the degree of contamination in this coastal system. Based on these last two indexes, San Jorge Bay has a serious problem of Cu and Pb pollution at the three sampling locations. However, only Cu exceeds the national maximum values used to evaluate ecological risk and the health of marine environments. It is suggested that Chilean environmental legislation for marine sediment quality--presently under technical discussion--is not an efficient tool for protecting the marine ecosystem.

  2. A variational approach to closed bosonic strings on bordered Riemann surfaces

    International Nuclear Information System (INIS)

    Ohrndorf, T.

    1987-01-01

    Polyakov's path integral for bosonic closed strings defined on a bordered Riemann surface is investigated by variational methods. It is demonstrated that boundary variations are generated by the Virasoro operators. The investigation is performed for both, simply connected Riemann surfaces as well as ringlike domains. It is shown that the form of the variational operator is the same on both kinds of surfaces. The Virasoro algebra arises as a consistency condition for the variation. (orig.)

  3. Nocturnal variation of air-surface temperature gradients for typical urban and rural surfaces

    Science.gov (United States)

    Swaid, Hanna

    The nocturnal variation of the standard atmospheric air-ground surface temperature gradient under fair weather conditions is considered. A semi-analytical model in the form of an exponential response function is proposed and experimentally verified against field observations conducted by the author at Haifa ( ca 32°N) and by others at various geographical locations. The proposed model is intended to predict the sought gradient variation with the aid of an experimentally derived parameter (a time constant) which is directly proportional to the thermal inertia of the substrate matter beneath the surface in question. Among the impervious ground-cover types widely encountered in urban environments, concrete surfaces exhibit the highest time constant of about 10 h, while that of bare dry rural soil is 6.5 h. Turf and wet soil surfaces, common in rural environments, have time constants of 3.6 and 10.8 h, respectively. Applicability of the proposed model to the exterior surfaces of building-envelope elements is also discussed, as are the implications of the present findings regarding the causative factors of urban heat islands.

  4. Effect of surface loading on the hydro-mechanical response of a tunnel in saturated ground

    Directory of Open Access Journals (Sweden)

    Simon Heru Prassetyo

    2016-09-01

    Full Text Available The design of underground spaces in urban areas must account not only for the current overburden load but also for future surface loads, such as from construction of high-rise buildings above underground structures. In saturated ground, the surface load will generate an additional mechanical response through stress changes and ground displacement, as well as a hydraulic response through pore pressure changes. These hydro-mechanical (H-M changes can severely influence tunnel stability. This paper examines the effect of surface loading on the H-M response of a typical horseshoe-shaped tunnel in saturated ground. Two tunnel models were created in the computer code Fast Lagrangian Analysis of Continua (FLAC. One model represented weak and low permeability ground (stiff clay, and the other represented strong and high permeability ground (weathered granite. Each of the models was run under two liner permeabilities: permeable and impermeable. Two main cases were compared. In Case 1, the surface load was applied 10 years after tunnel construction. In Case 2, the surface load was applied after the steady state pore pressure condition was achieved. The simulation results show that tunnels with impermeable liners experienced the most severe influence from the surface loading, with high pore pressures, large inward displacement around the tunnels, and high bending moments in the liner. In addition, the severity of the response increased toward steady state. This induced H-M response was worse for tunnels in clay than for those in granite. Furthermore, the long-term liner stabilities in Case 1 and Case 2 were similar, indicating that the influence of the length of time between when the tunnel was completed and when the surface load was applied was negligible. These findings suggest that under surface loading, in addition to the ground strength, tunnel stability in saturated ground is largely influenced by liner permeability and the long-term H-M response of

  5. Analysis of host genetic diversity and viral entry as sources of between-host variation in viral load

    Science.gov (United States)

    Wargo, Andrew R.; Kell, Alison M.; Scott, Robert J.; Thorgaard, Gary H.; Kurath, Gael

    2012-01-01

    Little is known about the factors that drive the high levels of between-host variation in pathogen burden that are frequently observed in viral infections. Here, two factors thought to impact viral load variability, host genetic diversity and stochastic processes linked with viral entry into the host, were examined. This work was conducted with the aquatic vertebrate virus, Infectious hematopoietic necrosis virus (IHNV), in its natural host, rainbow trout. It was found that in controlled in vivo infections of IHNV, a suggestive trend of reduced between-fish viral load variation was observed in a clonal population of isogenic trout compared to a genetically diverse population of out-bred trout. However, this trend was not statistically significant for any of the four viral genotypes examined, and high levels of fish-to-fish variation persisted even in the isogenic trout population. A decrease in fish-to-fish viral load variation was also observed in virus injection challenges that bypassed the host entry step, compared to fish exposed to the virus through the natural water-borne immersion route of infection. This trend was significant for three of the four virus genotypes examined and suggests host entry may play a role in viral load variability. However, high levels of viral load variation also remained in the injection challenges. Together, these results indicate that although host genetic diversity and viral entry may play some role in between-fish viral load variation, they are not major factors. Other biological and non-biological parameters that may influence viral load variation are discussed.

  6. Effect of Surface Impulsive Thermal Loads on Fatigue Behavior of Constant Volume Propulsion Engine Combustor Materials

    National Research Council Canada - National Science Library

    Zhu, Dongming

    2004-01-01

    .... In this study, a simulated engine test rig has been established to evaluate thermal fatigue behavior of a candidate engine combustor material, Haynes 188, under superimposed CO2 laser surface impulsive thermal loads (30 to 100 Hz...

  7. Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Cheol Min; Qin, Hong Yi; Hong, Seok Jun; Jeon, Sang Hyuk; Kulkarni, Atul; Kim, Tae Sun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    During the Chemical mechanical planarization (CMP), the pad conditioning process can affect the pad surface characteristics. Among many CMP process parameters, the improper applied load on the conditioner arm may have adverse effects on the polyurethane pad. In this work, we evaluated the pad surface properties under the various conditioner arm applied during pad conditioning process. The conditioning pads were evaluated for surface topography, surface roughness parameters such as Rt and Rvk and Material removal rate (MRR) and within-wafer non-uniformity after wafer polishing. We observed that, the pad asperities were collapsed in the direction of conditioner rotation and blocks the pad pores applied conditioner load. The Rvk value and MRR were founded to be in relation with 4 > 1 > 7 kgF conditioner load. Hence, this study shows that, 4 kgF applied load by conditioner is most suitable for the pad conditioning during CMP.

  8. Pad for holding a load against a surface by suction

    International Nuclear Information System (INIS)

    Farmer, R.C.; Goldsmith, H.A.; Proudlove, M.J.

    1981-01-01

    This invention concerns suction pads for supporting loads. Specifically, the suction pad is part of a pair of pads located at the ends of a bridge forming a vehicle for transporting instruments for the non-destructive testing of a large vessel intended to contain a fuel assembly for a nuclear reactor immersed in a liquid metal coolant. For example, the vehicle is of the type described in the French patent application filed this day under the heading 'Vehicle for transporting instruments for testing against a wall' [fr

  9. Analysis and Control of STATCOM/SMES Compensator in a Load Variation Conditions

    Directory of Open Access Journals (Sweden)

    Mahmoud Reza Shakarami

    2014-01-01

    Full Text Available The utilization of Flexible AC Transmission System (FACTS devices in a power system can potentially overcome limitations of the present mechanically controlled transmission system. Also, the advanced technology makes it possible to include new energy storage devices in the electrical power system. The integration of Superconducting Magnetic Energy Storage (SMES into Static Synchronous Compensator (STATCOM can lead to increase their flexibility to improve power system dynamic behavior by exchanging both active and reactive powers with power grids. This paper describes structure and behavior of STATCOM/SMES compensator in power systems. A control strategy based on direct Lyapanov method for compensator is used. Moreover, the performance of the STATCOM/SMES compensator in a load variation condition is evaluated by PSCAD/EMTDC software in test system. Also, SMES capacity effects on integrated compensator are investigated.

  10. Correction of temperature-induced spectral variations by loading space standardization.

    Science.gov (United States)

    Chen, Zeng-Ping; Morris, Julian; Martin, Elaine

    2005-03-01

    With a view to maintaining the validity of multivariate calibration models for chemical processes affected by temperature fluctuations, loading space standardization (LSS) is proposed. Through the application of LSS, multivariate calibration models built at temperatures other than those of the test samples can provide predictions with an accuracy comparable to the results obtained at a constant temperature. Compared with other methods, designed for the same purpose, such as continuous piecewise direct standardization, LSS has the advantages of straightforward implementation and good performance. The methodology was applied to shortwave NIR spectral data sets measured at different temperatures. The results showed that LSS can effectively remove the influence of temperature variations on the spectra and maintain the predictive abilities of the multivariate calibration models.

  11. Long-term visibility variation in Athens (1931–2013: a proxy for local and regional atmospheric aerosol loads

    Directory of Open Access Journals (Sweden)

    D. Founda

    2016-09-01

    Full Text Available This study explores the interdecadal variability and trends of surface horizontal visibility at the urban area of Athens from 1931 to 2013, using the historical archives of the National Observatory of Athens (NOA. A prominent deterioration of visibility in the city was detected, with the long-term linear trend amounting to −2.8 km decade−1 (p < 0.001, over the entire study period. This was not accompanied by any significant trend in relative humidity or precipitation over the same period. A slight recovery of visibility levels seems to be established in the recent decade (2004–2013. It was found that very good visibility (>  20 km occurred at a frequency of 34 % before the 1950s, while this percentage drops to just 2 % during the decade 2004–2013. The rapid impairment of the visual air quality in Athens around the 1950s points to the increased levels of air pollution on a local and/or regional scale, related to high urbanization rates and/or increased anthropogenic emissions on a global scale at that period. Visibility was found to be negatively/positively correlated with relative humidity/wind speed, the correlation being statistically valid at certain periods. Wind regime and mainly wind direction and corresponding air mass origin were found to highly control visibility levels in Athens. The comparison of visibility variation in Athens and at a non-urban reference site on Crete island revealed similar negative trends over the common period of observations. This suggests that apart local sources, visibility in Athens is highly determined by aerosol load of regional origin. AVHRR and MODIS satellite-derived aerosol optical depth (AOD retrievals over Athens and surface measurements of PM10 confirmed the relation of visibility to aerosol load.

  12. Riparian shrub buffers reduce surface water pollutant loads

    Science.gov (United States)

    W. A. Geyer; C. Barden; K. Mankin; D. Devlin

    2003-01-01

    Surface water resources in Kansas often contain concentrations of pesticides, nutrients, and sediments that are of concern to local citizens. The United States Geological Survey reported in 1999 that 97 percent of streams and 82 percent of lakes in Kansas would not fully support all uses as designated by state statutes (U.S. Geological Survey 1999). Bacteria and...

  13. Optimized design of thermo-mechanically loaded non-uniform bars by using a variational method

    Science.gov (United States)

    Nayak, P.; Saha, K. N.

    2016-08-01

    The present paper evaluates the axial strain and stress of a thermo-mechanically loaded non-uniform bar by using a numerical method based on a variational principle. The solutions are obtained up to the elastic limit of the material based on the assumptions that material properties are independent of temperature variation and plane cross-sections remain plane maintaining axisymmetry. This approximation is carried out by Galerkin's principle, using a linear combination of sets of orthogonal co-ordinate functions which satisfy prescribed boundary conditions. The solution algorithm is implemented with the help of MATLAB® computational simulation software. Some numerical results of thermoelastic field are presented and discussed for different bar materials such as mild steel, copper, aluminium alloy 6061 (Al alloy 6061), aluminium alloy 7075 (Al alloy 7075) and diamond. The effect of geometry parameters like aspect ratio, slenderness ratio and the type of taperness is investigated and the relevant results are obtained in dimensional form. The term bar used in this paper is in generic sense and hence the formulation is applicable for all one dimensional elements, e.g., rods, pipes, truss members, etc.

  14. Effect of natural ageing on surface of silver loaded TPE and its influence in antimicrobial efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Tomacheski, Daiane, E-mail: daitomacheski@gmail.com [Department of Materials Engineering, Laboratory of Polymers – LAPOL, Universidade Federal do Rio Grande do Sul, UFRGS, 9500 Bento Gonçalves Avenue, Postal Code 15010, Porto Alegre 91501-970 (Brazil); Softer Brasil Compostos Termoplásticos LTDA, 275 Edgar Hoffmeister Avenue, Campo Bom 93700-000 (Brazil); Pittol, Michele [Softer Brasil Compostos Termoplásticos LTDA, 275 Edgar Hoffmeister Avenue, Campo Bom 93700-000 (Brazil); Simões, Douglas Naue; Ribeiro, Vanda Ferreira [Department of Materials Engineering, Laboratory of Polymers – LAPOL, Universidade Federal do Rio Grande do Sul, UFRGS, 9500 Bento Gonçalves Avenue, Postal Code 15010, Porto Alegre 91501-970 (Brazil); Softer Brasil Compostos Termoplásticos LTDA, 275 Edgar Hoffmeister Avenue, Campo Bom 93700-000 (Brazil); Santana, Ruth Marlene Campomanes [Department of Materials Engineering, Laboratory of Polymers – LAPOL, Universidade Federal do Rio Grande do Sul, UFRGS, 9500 Bento Gonçalves Avenue, Postal Code 15010, Porto Alegre 91501-970 (Brazil)

    2017-05-31

    Highlights: • Ag loaded TPE lost their antimicrobial efficacy after polymer degradation. • Modifications in Ag loaded TPE surface provide conditions to bacteria settlement. • Rough TPE surface and the low γ{sub S}{sup +} was more favorable for bacterial development. - Abstract: The aim of this study is to characterize the modifications in silver loaded TPE surfaces exposed to weathering and their relation to susceptibility to microbial attack. Silver loaded TPE materials were exposed to natural ageing for nine months and modifications in antimicrobial properties and surface characteristics were evaluated. Chemical changes were investigated by using the infrared spectra. The average surface roughness and topography were determined by atomic force microscopy. Contact angle was measured to verify wettability conditions and surface free energy (SFE). After nine months of exposure, a decrease in the antimicrobial properties of loaded TPE compounds was observed. A reduction in surface roughness and improvement in wettability and high values of polar component of SFE were verified. The best antibacterial action was noticed in the sample with high Lewis acid force, lower roughness and lower carbonyl index.

  15. Contact models of repaired articular surfaces: influence of loading conditions and the superficial tangential zone.

    Science.gov (United States)

    Owen, John R; Wayne, Jennifer S

    2011-07-01

    The superficial tangential zone (STZ) plays a significant role in normal articular cartilage's ability to support loads and retain fluids. To date, tissue engineering efforts have not replicated normal STZ function in cartilage repairs. This finite element study examined the STZ's role in normal and repaired articular surfaces under different contact conditions. Contact area and pressure distributions were allowed to change with time, tension-compression nonlinearity modeled collagen behavior in the STZ, and nonlinear geometry was incorporated to accommodate finite deformation. Responses to loading via impermeable and permeable rigid surfaces were compared to loading via normal cartilage, a more physiologic condition, anticipating the two rigid loading surfaces would bracket that of normal. For models loaded by normal cartilage, an STZ placed over the inferior repair region reduced the short-term axial compression of the articular surface by 15%, when compared to a repair without an STZ. Covering the repair with a normal STZ shifted the flow patterns and strain levels back toward that of normal cartilage. Additionally, reductions in von Mises stress (21%) and an increase in fluid pressure (13%) occurred in repair tissue under the STZ. This continues to show that STZ properties of sufficient quality are likely critical for the survival of transplanted constructs in vivo. However, response to loading via normal cartilage did not always fall within ranges predicted by the rigid surfaces. Use of more physiologic contact models is recommended for more accurate investigations into properties critical to the success of repair tissues.

  16. Influences of crustal thickening in the Tibetan Plateau on loading modeling and inversion associated with water storage variation

    Directory of Open Access Journals (Sweden)

    Hansheng Wang

    2015-05-01

    Full Text Available We use the average crustal structure of the CRUST1.0 model for the Tibetan Plateau to establish a realistic earth model termed as TC1P, and data from the Global Land Data Assimilation System (GLDAS hydrology model and Gravity Recovery and Climate Experiment (GRACE data, to generate the hydrology signals assumed in this study. Modeling of surface radial displacements and gravity variation is performed using both TC1P and the global Preliminary Reference Earth Model (PREM. Furthermore, inversions of the hydrology signals based on simulated Global Positioning System (GPS and GRACE data are performed using PREM. Results show that crust in TC1P is harder and softer than that in PREM above and below a depth of 15 km, respectively, causing larger differences in the computed load Love numbers and loading Green's functions. When annual hydrology signals are assumed, the differences of the radial displacements are found to be as large as approximately 0.6 mm for the truncated degree of 180; while for hydrology-trend signals the differences are very small. When annual hydrology signals and the trends are assumed, the differences in the surface gravity variation are very small. It is considered that TC1P can be used to efficiently remove the hydrological effects on the monitoring of crustal movement. It was also found that when PREM is used inappropriately, the inversion of the hydrology signals from simulated annual GPS signals can only recover approximately 88.0% of the annual hydrology signals for the truncated degree of 180, and the inversion of hydrology signals from the simulated trend GPS signals can recover approximately 92.5% for the truncated degree of 90. However, when using the simulated GRACE data, it is possible to recover almost 100%. Therefore, in future, the TC1P model can be used in the inversions of hydrology signals based on GPS network data. PREM is also valid for use with inversions of hydrology signals from GRACE data at resolutions

  17. Critical heat flux variations on CANDU calandria tube surface

    Energy Technology Data Exchange (ETDEWEB)

    Behdadi, A.; Luxat, J.C., E-mail: behdada@mcmaster.ca, E-mail: luxatj@mcmaster.ca [McMaster Univ., Engineering Physics Dept., Hamilton, Ontario (Canada)

    2012-07-01

    Heavy water moderator surrounding each fuel channel is one of the important safety features in CANDU reactors since it provides an in-situ passive heat sink for the fuel in situations where other engineered means of heat removal from fuel channels have failed. In a critical break LOCA scenario, fuel cooling becomes severely degraded due to rapid flow reduction in the affected flow pass of the heat transport system. This can result in pressure tubes experiencing significant heat-up during early stages of the accident when coolant pressure is still high, thereby causing uniform thermal creep strain (ballooning) of the pressure tube (PT) into contact with its calandria tube (CT). The contact of the hot PT with the CT causes rapid redistribution of stored heat from the PT to CT and a large heat flux spike from the CT to the moderator fluid. For conditions where subcooling of the moderator fluid is low, this heat flux spike can cause dryout of the CT. This can detrimentally affect channel integrity if the CT post-dryout temperature becomes sufficiently high to result in continued thermal creep strain deformation of both the PT and the CT. The focus of this work is to develop a mechanistic model to predict Critical Heat Flux (CHF) on the CT surface following a contact with its pressure tube. A mechanistic CHF model is applied based on a concept of wall dry patch formation, prevention of rewetting and subsequent dry patch spreading. Results have been compared to an empirical correlation and a good agreement has been obtained. The model has been used to predict the spatial variation of CHF over a cylinder with dimensions of CANDU CT. (author)

  18. Regional scale selenium loading associated with surface coal mining, Elk Valley, British Columbia, Canada.

    Science.gov (United States)

    Wellen, Christopher C; Shatilla, Nadine J; Carey, Sean K

    2015-11-01

    Selenium (Se) concentrations in surface water downstream of surface mining operations have been reported at levels in excess of water quality guidelines for the protection of wildlife. Previous research in surface mining environments has focused on downstream water quality impacts, yet little is known about the fundamental controls on Se loading. This study investigated the relationship between mining practices, stream flows and Se concentrations using a SPAtially Referenced Regression On Watershed attributes (SPARROW) model. This work is part of a R&D program examining the influence of surface coal mining on hydrological and water quality responses in the Elk Valley, British Columbia, Canada, aimed at informing effective management responses. Results indicate that waste rock volume, a product of mining activity, accounted for roughly 80% of the Se load from the Elk Valley, while background sources accounted for roughly 13%. Wet years were characterized by more than twice the Se load of dry years. A number of variables regarding placement of waste rock within the catchments, length of buried streams, and the construction of rock drains did not significantly influence the Se load. The age of the waste rock, the proportion of waste rock surface reclaimed, and the ratio of waste rock pile side area to top area all varied inversely with the Se load from watersheds containing waste rock. These results suggest operational practices that are likely to reduce the release of Se to surface waters. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Bone response to immediate loading through titanium implants with different surface roughness in rats.

    Science.gov (United States)

    Sato, Naoko; Kuwana, Toshie; Yamamoto, Miou; Suenaga, Hanako; Anada, Takahisa; Koyama, Shigeto; Suzuki, Osamu; Sasaki, Keiichi

    2014-07-01

    Because of its high predictability of success, implant therapy is a reliable treatment for replacement of missing teeth. The concept of immediate implant loading has been widely accepted in terms of early esthetic and functional recovery. However, there is little biological evidence to support this concept. The objective of this study was to examine the interactive effects of mechanical loading and surface roughness of immediately loaded titanium implants on bone formation in rats. Screw-shaped anodized titanium implants were either untreated (smooth) or acid-etched. Two implants were inserted parallel to each other in the tibiae of rats, and a closed coil spring (2.0 N) was immediately applied. Trabecular and cortical bone around both implants was analyzed using microtomographic images, and a removal torque test was performed at weeks 1, 2, and 4. Immediate loading of acid-etched implants resulted in significant decreases in bone mineral density, contact surface area, and cortical bone thickness. These effects were not observed after immediate loading of smooth implants. Conversely, loading did not influence acid-etched implant fixation; however, smooth implant fixation at week 1 was significantly reduced. These results imply that surface roughness regulates bone response to mechanical stress and that immediate loading might not inhibit osseointegration for smooth and rough implants in the late healing stages.

  20. Unscheduled load flow effect due to large variation in the distributed generation in a subtransmission network

    Science.gov (United States)

    Islam, Mujahidul

    A sustainable energy delivery infrastructure implies the safe and reliable accommodation of large scale penetration of renewable sources in the power grid. In this dissertation it is assumed there will be no significant change in the power transmission and distribution structure currently in place; except in the operating strategy and regulatory policy. That is to say, with the same old structure, the path towards unveiling a high penetration of switching power converters in the power system will be challenging. Some of the dimensions of this challenge are power quality degradation, frequent false trips due to power system imbalance, and losses due to a large neutral current. The ultimate result is the reduced life of many power distribution components - transformers, switches and sophisticated loads. Numerous ancillary services are being developed and offered by the utility operators to mitigate these problems. These services will likely raise the system's operational cost, not only from the utility operators' end, but also reflected on the Independent System Operators and by the Regional Transmission Operators (RTO) due to an unforeseen backlash of frequent variation in the load-side generation or distributed generation. The North American transmission grid is an interconnected system similar to a large electrical circuit. This circuit was not planned but designed over 100 years. The natural laws of physics govern the power flow among loads and generators except where control mechanisms are installed. The control mechanism has not matured enough to withstand the high penetration of variable generators at uncontrolled distribution ends. Unlike a radial distribution system, mesh or loop networks can alleviate complex channels for real and reactive power flow. Significant variation in real power injection and absorption on the distribution side can emerge as a bias signal on the routing reactive power in some physical links or channels that are not distinguishable

  1. Power monitoring in dielectric-loaded surface plasmon-polariton waveguides.

    Science.gov (United States)

    Kumar, Ashwani; Gosciniak, Jacek; Andersen, Thomas B; Markey, Laurent; Dereux, Alain; Bozhevolnyi, Sergey I

    2011-02-14

    We report on propagating mode power monitoring in dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs) by measuring the resistance of gold stripes supporting the DLSPPW mode propagation. Inevitable absorption of the DLSPPW mode in metal causes an increase in the stripe temperature and, thereby, in its resistance whose variations are monitored with an external Wheatstone bridge being accurately balanced in the absence of radiation in a waveguide. The investigated waveguide configuration consists of a 1-µm-thick and 10-µm-wide polymer ridges tapered laterally to a 1-µm-wide ridge placed on a 50-nm-thin and 4-µm-wide gold stripe, all supported by a magnesium fluoride substrate. Using single-mode polarization-maintaining fiber for in- and out-coupling of radiation, DLSPPW mode power monitoring at telecom wavelengths is realized with the responsivities of up to ~1.8 µV/µW (showing weak wavelength dependence) being evaluated for a bias voltage of 1 V.

  2. Variation in phenotype, parasite load and male competitive ability across a cryptic hybrid zone.

    Directory of Open Access Journals (Sweden)

    Devi Stuart-Fox

    2009-05-01

    Full Text Available Molecular genetic studies are revealing an increasing number of cryptic lineages or species, which are highly genetically divergent but apparently cannot be distinguished morphologically. This observation gives rise to three important questions: 1 have these cryptic lineages diverged in phenotypic traits that may not be obvious to humans; 2 when cryptic lineages come into secondary contact, what are the evolutionary consequences: stable co-existence, replacement, admixture or differentiation and 3 what processes influence the evolutionary dynamics of these secondary contact zones?To address these questions, we first tested whether males of the Iberian lizard Lacerta schreiberi from two highly genetically divergent, yet morphologically cryptic lineages on either side of an east-west secondary contact could be differentiated based on detailed analysis of morphology, coloration and parasite load. Next, we tested whether these differences could be driven by pre-copulatory intra-sexual selection (male-male competition. Compared to eastern males, western males had fewer parasites, were in better body condition and were more intensely coloured. Although subtle environmental variation across the hybrid zone could explain the differences in parasite load and body condition, these were uncorrelated with colour expression, suggesting that the differences in coloration reflect heritable divergence. The lineages did not differ in their aggressive behaviour or competitive ability. However, body size, which predicted male aggressiveness, was positively correlated with the colour traits that differed between genetic backgrounds.Our study confirms that these cryptic lineages differ in several aspects that are likely to influence fitness. Although there were no clear differences in male competitive ability, our results suggest a potential indirect role for intra-sexual selection. Specifically, if lizards use the colour traits that differ between genetic

  3. Excitation of plane Lamb wave in plate-like structures under applied surface loading

    Science.gov (United States)

    Zhou, Kai; Xu, Xinsheng; Zhao, Zhen; Yang, Zhengyan; Zhou, Zhenhuan; Wu, Zhanjun

    2018-02-01

    Lamb waves play an important role in structure health monitoring (SHM) systems. The excitation of Lamb waves has been discussed for a long time with absorbing results. However, little effort has been made towards the precise characterization of Lamb wave excitation by various transducer models with mathematical foundation. In this paper, the excitation of plane Lamb waves with plane strain assumption in isotropic plate structures under applied surface loading is solved with the Hamiltonian system. The response of the Lamb modes excited by applied loading is expressed analytically. The effect of applied loading is divided into the product of two parts as the effect of direction and the effect of distribution, which can be changed by selecting different types of transducer and the corresponding transducer configurations. The direction of loading determines the corresponding displacement of each mode. The effect of applied loading on the in-plane and normal directions depends on the in-plane and normal displacements at the surface respectively. The effect of the surface loading distribution on the Lamb mode amplitudes is mainly reflected by amplitude versus frequency or wavenumber. The frequencies at which the maxima and minima of the S0 or A0 mode response occur depend on the distribution of surface loading. The numerical results of simulations conducted on an infinite aluminum plate verify the theoretical prediction of not only the direction but also the distribution of applied loading. A pure S0 or A0 mode can be excited by selecting the appropriate direction and distribution at the corresponding frequency.

  4. Predicting Near-Surface Meteorological Variations over Different Vegetation Types

    NARCIS (Netherlands)

    Hutjes, R.W.A.; Klaassen, W.; Kruijt, B.; Veen, A.W.L.

    1991-01-01

    Meteorological conditions close to a surface are strongly influenced by the properties of the surface itself. As a result, input data for models calculating evaporation of surfaces differing from the measurement site need to be transformed. A transformation scheme proposed previously is tested on

  5. Anticoagulation and endothelial cell behaviors of heparin-loaded graphene oxide coating on titanium surface

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Chang-Jiang, E-mail: panchangjiang@hyit.edu.cn [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China); Pang, Li-Qun [Department of General Surgery, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an 223300 (China); Gao, Fei [Zhejiang Zylox Medical Devices Co., Ltd., Hangzhou 310000 (China); Wang, Ya-Nan; Liu, Tao; Ye, Wei; Hou, Yan-Hua [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai' an 223003 (China)

    2016-06-01

    Owing to its unique physical and chemical properties, graphene oxide (GO) has attracted tremendous interest in many fields including biomaterials and biomedicine. The purpose of the present study is to investigate the endothelial cell behaviors and anticoagulation of heparin-loaded GO coating on the titanium surface. To this end, the titanium surface was firstly covered by the polydopamine coating followed by the deposition of the GO coating. Heparin was finally loaded on the GO coating to improve the blood compatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that the heparin-loaded GO coating was successfully created on the titanium surface. The scanning electron microscopy (SEM) images indicated that a relative uniform GO coating consisting of multilayer GO sheets was formed on the substrate. The hydrophilicity of the titanium surface was enhanced after the deposition of GO and further improved significantly by the loading heparin. The GO coating can enhance the endothelial cell adhesion and proliferation as compared with polydopamine coating and the blank titanium. Loading heparin on the GO coating can significantly reduce the platelet adhesion and prolong the activated partial thromboplastin time (APTT) while not influence the endothelial cell adhesion and proliferation. Therefore, the heparin-loaded GO coating can simultaneously enhance the cytocompatibility to endothelial cells and blood compatibility of biomaterials. Because the polydopamine coating can be easily prepared on most of biomaterials including polymer, ceramics and metal, thus the approach of the present study may open up a new window of promising an effective and efficient way to promote endothelialization and improve the blood compatibility of blood-contact biomedical devices such as intravascular stents. - Highlights: • Heparin-loaded graphene oxide coating was

  6. An efficient domain decomposition strategy for wave loads on surface piercing circular cylinders

    DEFF Research Database (Denmark)

    Paulsen, Bo Terp; Bredmose, Henrik; Bingham, Harry B.

    2014-01-01

    A fully nonlinear domain decomposed solver is proposed for efficient computations of wave loads on surface piercing structures in the time domain. A fully nonlinear potential flow solver was combined with a fully nonlinear Navier–Stokes/VOF solver via generalized coupling zones of arbitrary shape....... Sensitivity tests of the extent of the inner Navier–Stokes/VOF domain were carried out. Numerical computations of wave loads on surface piercing circular cylinders at intermediate water depths are presented. Four different test cases of increasing complexity were considered; 1) weakly nonlinear regular waves...

  7. Estimation of real-time N load in surface water using dynamic data driven application system

    Science.gov (United States)

    Y. Ouyang; S.M. Luo; L.H. Cui; Q. Wang; J.E. Zhang

    2011-01-01

    Agricultural, industrial, and urban activities are the major sources for eutrophication of surface water ecosystems. Currently, determination of nutrients in surface water is primarily accomplished by manually collecting samples for laboratory analysis, which requires at least 24 h. In other words, little to no effort has been devoted to monitoring real-time variations...

  8. Variation in size of blood puddles on different surfaces.

    Science.gov (United States)

    Kreutziger, Janett; Haim, Andreas; Jonsson, Kim; Wenzel, Volker; Stark, Matthias; Nussbaumer, Walter

    2014-10-01

    It is known that visual estimation of blood loss is inaccurate independently from experience and qualification of rescuers or members of hospital staff. There is no information available about the size of a puddle of blood for a given amount of blood depending on the surface. This pilot study evaluated the size of blood puddles on various surfaces. Human blood was portioned in standardized amounts of fluid and poured on different surfaces: wooden and polyvinyl chloride (PVC) floors, flagging, carpet, asphalt, concrete, forest soil, mattress and towel. The resulting puddles of blood were documented by digital photos and their surface areas measured using a computer. The largest blood puddles were found on even surfaces such as PVC floors and concrete, and the smallest blood puddles were found on forest soil and carpet. When blood volume was 100 ml, the difference between the smallest and the largest blood puddle added up to a factor of 13.8 (77 cm forest soil, 1061 cm PVC). This factor was comparable in all other blood amounts on these two surfaces (13.7 with 250 ml, 13.0 with 500 ml, 13.5 with 1000 ml). A table with objects of daily life of comparable size (CD, letter, newspaper, etc.) was added for teaching purposes. The size of puddles of blood depended strongly on the type of surface. Up to 13 times larger blood puddles were found on hard and nonabsorbant surfaces (PVC, concrete) than on absorbant surfaces such as carpet or forest soil.

  9. Spatial and temporal variations of loads and sources of total and dissolved Phosphorus in a set of rivers (Western France).

    Science.gov (United States)

    Legeay, Pierre-Louis; Moatar, Florentina; Gascuel-Odoux, Chantal; Gruau, Gérard

    2015-04-01

    In intensive agricultural regions with important livestock farming, long-term land application of Phosphorus (P) both as chemical fertilizer and animal wastes, have resulted in elevated P contents in soils. Since we know that high P concentrations in rivers is of major concern, few studies have been done at to assess the spatiotemporal variability of P loads in rivers and apportionment of point and nonpoint source in total loads. Here we focus on Brittany (Western France) where even though P is a great issue in terms of human and drinking water safety (cyano-toxins), environmental protection and economic costs for Brittany with regards to the periodic proliferations of cyanobacteria that occur every year in this region, no regional-scale systematic study has been carried out so far. We selected a set of small rivers (stream order 3-5) with homogeneous agriculture and granitic catchment. By gathering data from three water quality monitoring networks, covering more than 100 measurements stations, we provide a regional-scale quantification of the spatiotemporal variability of dissolved P (DP) and total P (TP) interannual loads from 1992 to 2012. Build on mean P load in low flows and statistical significance tests, we developed a new indicator, called 'low flow P load' (LFP-load), which allows us to determine the importance of domestic and industrial P sources in total P load and to assess their spatiotemporal variability compared to agricultural sources. The calculation and the map representation of DP and TP interannual load variations allow identification of the greatest and lowest P contributory catchments over the study period and the way P loads of Brittany rivers have evolved through time. Both mean DP and TP loads have been divided by more than two over the last 20 years. Mean LFDP-load decreased by more than 60% and mean LFTP-load by more than 45% on average over the same period showing that this marked temporal decrease in total load is largely due to the

  10. Visual Assessment of Surface Fuel Loads Does Not Align with Destructively Sampled Surface Fuels

    Directory of Open Access Journals (Sweden)

    Sarah C. McColl-Gausden

    2017-10-01

    Full Text Available Fuel load and structure are fundamental drivers of fire behaviour. Accurate data is required for managers and researchers to better understand our ability to alter fire risk. While there are many ways to quantify fuel, visual assessment methods are generally considered the most efficient. Visual hazard assessments are commonly used by managers, government agencies and consultants to provide a fuel hazard score or rating but not a quantity of fuel. Many systems attempt to convert the hazard score or rating to a fuel load for use in fire behaviour models. Here we investigate whether the conversion table in the widely used Overall Fuel Hazard Guide (OFHG matches destructively sampled fuel loads from 116 sites across five forest types. We specifically examine whether there are quantifiable differences that can be attributed to forest type. We found there is overlap between the two methods for low, moderate and high hazard categories, however for the very high and extreme hazard categories, visual assessment overestimated fuel load in four of the five forest types. Using a commonly applied fire behaviour model, we found that the overestimation of fuel load in very high and extreme hazard categories leads to an overestimation of fire behavior in these hazard categories.

  11. Variation of surface electric field during geomagnetic disturbed ...

    Indian Academy of Sciences (India)

    storm current generators, through the ionosphere, and down to the Earth's surface in the fair ... Atmospheric electric field; magnetic storm; magnetosphere; ionosphere; global electrical circuit. J. Earth Syst. Sci. 124, No. 8, December ... electrical conductivity of the ice surface is in sev- eral orders of magnitude higher than that ...

  12. Combining Unsteady Blade Pressure Measurements and a Free-Wake Vortex Model to Investigate the Cycle-to-Cycle Variations in Wind Turbine Aerodynamic Blade Loads in Yaw

    Directory of Open Access Journals (Sweden)

    Moutaz Elgammi

    2016-06-01

    Full Text Available Prediction of the unsteady aerodynamic flow phenomenon on wind turbines is challenging and still subject to considerable uncertainty. Under yawed rotor conditions, the wind turbine blades are subjected to unsteady flow conditions as a result of the blade advancing and retreating effect and the development of a skewed vortical wake created downstream of the rotor plane. Blade surface pressure measurements conducted on the NREL Phase VI rotor in yawed conditions have shown that dynamic stall causes the wind turbine blades to experience significant cycle-to-cycle variations in aerodynamic loading. These effects were observed even though the rotor was subjected to a fixed speed and a uniform and steady wind flow. This phenomenon is not normally predicted by existing dynamic stall models integrated in wind turbine design codes. This paper couples blade pressure measurements from the NREL Phase VI rotor to a free-wake vortex model to derive the angle of attack time series at the different blade sections over multiple rotor rotations and three different yaw angles. Through the adopted approach it was possible to investigate how the rotor self-induced aerodynamic load fluctuations influence the unsteady variations in the blade angles of attack and induced velocities. The hysteresis loops for the normal and tangential load coefficients plotted against the angle of attack were plotted over multiple rotor revolutions. Although cycle-to-cycle variations in the angles of attack at the different blade radial locations and azimuth positions are found to be relatively small, the corresponding variations in the normal and tangential load coefficients may be significant. Following a statistical analysis, it was concluded that the load coefficients follow a normal distribution at the majority of blade azimuth angles and radial locations. The results of this study provide further insight on how existing engineering models for dynamic stall may be improved through

  13. Ulva linza zoospore sensitivity to systematic variation of surface topography

    Science.gov (United States)

    Sheats, Julian Taylor

    The use of surface topographical microstructure is abundant in nature. The lotus plant uses a fractal-like topography to create a highly non-wetting surface that self-cleans as water drops take dirt particles with them as they roll off. Analysis of how topography affects surface interactions offers a unique opportunity to attack a problem that affects our economy and societal health significantly. The attachment of biological material to manmade surfaces can be looked at as fouling or directed adhesion. Marine fouling on ship hulls costs the United States $600 million each year due to increased fuel usage caused by drag. Hospital-acquired methicillin-resistant Staphylococcus aureus infections cause thousands of deaths annually as a result of colonization of hospital surfaces. The lack of biocompatible synthetic surfaces for implants such as vascular grafts lead to restenosis as cells are unable to develop a natural interaction with the graft surface. In each circumstance there is much to learn about the complicated attachment process. This work expands the investigation of the role of topography in the attachment of the green fouling algae Ulva linza to poly(dimethylsiloxane) surfaces. Spore attachment density was correlated to the Wenzel roughness ratio on low surface energy, high-modulus poly(dimethylsiloxane)-grafted-silicon topographies. The role of topography on a scale less than the size of a spore was investigated on nano-roughened poly(dimethylsiloxane) elastomer surfaces. For a specific group of patterns, the spatial distribution of spores attached to topographies was quantitatively analyzed and shown to correlate with feature dimensions.

  14. On the Pressure Distribution in a Porous Media under a Spherical Loading Surface

    Science.gov (United States)

    Wang, Qiuyun; Zhu, Zenghao; Nathan, Rungun; Wu, Qianhong

    2017-11-01

    The phenomenon of pressure generation and relaxation inside a porous media is widely observed in biological systems. Herein, we report a biomimetic study to examine the pressure distribution inside a soft porous layer when a spherical loaded surface suddenly impacts on it. A novel experimental setup was developed that includes a fully instrumented spherical piston and a soft fibrous porous layer underneath. Extensive experimental study was performed with different porous materials, different loadings and different sized loading surfaces. The pore pressure generation and the motion of the loading surface were recorded. A novel theoretical model was developed to characterize the pressure field during the process. Excellent agreement was observed between the experimental results and the theoretically predictions. It shows that the pressure generation is governed by the Brinkman parameter, α = h/Kp0.5, where h is the porous layer thickness, and Kp is the undeformed permeability. The study improves our understanding of the dynamic response of soft porous media under rapid compression. It has board impact on the study of transient load bearing in biological systems and industry applications. This work was supported by the National Science Foundation (NSF CBET) under Award #1511096.

  15. Effect of immediate or delayed loading following immediate placement of implants with a modified surface.

    Science.gov (United States)

    Liñares, A; Mardas, N; Dard, M; Donos, N

    2011-01-01

    to evaluate the effect of the timing of loading on bone-to-implant contact (BIC) following immediate placement of implants with a hydrophilic sandblasted, large-grit and acid-etched surface (modSLA) into fresh extraction sockets in a minipig model. six minipigs were used in this study. In each hemi-mandible, two conical shape implants (TE, Straumann implants) with a hydrophilic surface (modSLA) were placed in fresh extraction sockets. In one side of the mandible (control), two implants were immediately placed in fresh extraction sockets. The implants were loaded after 4 weeks of healing. At the contralateral side (test), two implants were immediately placed and loaded. After 8 weeks of healing, the animals were sacrificed and histologically analysed. during the experimental period, no implants were lost and all of them presented to be osseointegrated. The percentage of BIC was similar in both groups: 66.1% and 65.1% for the control and test group, respectively. Furthermore, the distance from the shoulder of the implant to bone crest and the distance from the shoulder to the first BIC were similar in both groups. immediate implant placement and loading showed similar BIC with immediate placement and delayed loading when implants with a modSLA surface were used. Both procedures showed similar buccal bone crest levels, which presented some resorption irrespective of the treatment modality.

  16. The pore-load modulus of ordered nanoporous materials with surface effects

    Science.gov (United States)

    Liu, Mingchao; Wu, Jian; Gan, Yixiang; Chen, C. Q.

    2016-03-01

    Gas and liquid adsorption-induced deformation of ordered porous materials is an important physical phenomenon with a wide range of applications. In general, the deformation can be characterized by the pore-load modulus and, when the pore size reduces to nanoscale, it is affected by surface effects and shows prominent size-dependent features. In this Letter, the influence of surface effects on the elastic properties of ordered nanoporous materials with internal pressure is accounted for in a single pore model. A porosity and surface elastic constants dependent closed form solution for the size dependent pore-load modulus is obtained and verified by finite element simulations and available experimental results. In addition, it is found to depend on the geometrical arrangement of pores. This study provides an efficient tool to analyze the surface effects on the elastic response of ordered nanoporous materials.

  17. The Fracture of Plasma-Treated Polyurethane Surface under Fatigue Loading

    Directory of Open Access Journals (Sweden)

    Ilya A. Morozov

    2018-02-01

    Full Text Available Plasma treatment of soft polymers is a promising technique to improve biomedical properties of the materials. The response to the deformation of such materials is not yet clear. Soft elastic polyurethane treated with plasma immersion ion implantation is subjected to fatigue uniaxial loading. The influence of the strain amplitude and the plasma treatment regime on damage character is discussed. Surface defects are studied in unloaded and stretched states of the material. As a result of fatigue loading, transverse cracks (with closed overlapping edges as well as with open edges deeply propagating into the polymer and longitudinal folds which are break and bend inward, appear on the surface. Hard edges of cracks cut the soft polymer which is squeezed from the bulk to the surface. The observed damages are related to the high stiffness of the modified surface and its transition to the polymer substrate.

  18. Study of surfaces and surface layers on high temperature materials after short-time thermal loads

    International Nuclear Information System (INIS)

    Bolt, H.; Hoven, H.; Koizlik, K.; Linke, J.; Nickel, H.; Wallura, E.

    1985-11-01

    Being part of the plasma-wall interaction during TOKAMAK operation, erosion- and redeposition processes of First Wall materials substantially influence plasma parameters as well as the properties of the First Wall. An important redeposition process of eroded material is the formation of thin films by atomic condensation. Examinations of First Wall components after TOKAMAK operation lead to the assumption that these thin metallic films tend to agglomerate to small particles under subsequent heat load. In laboratory experiments it is shown that thin metallic films on various substrates can agglomerate under short time high heat fluxes and also under longer lasting lower thermal loads, thus verifying the ''agglomeration hypothesis''. (orig.) [de

  19. Risk analysis of breakwater caisson under wave attack using load surface approximation

    Science.gov (United States)

    Kim, Dong Hyawn

    2014-12-01

    A new load surface based approach to the reliability analysis of caisson-type breakwater is proposed. Uncertainties of the horizontal and vertical wave loads acting on breakwater are considered by using the so-called load surfaces, which can be estimated as functions of wave height, water level, and so on. Then, the first-order reliability method (FORM) can be applied to determine the probability of failure under the wave action. In this way, the reliability analysis of breakwaters with uncertainties both in wave height and in water level is possible. Moreover, the uncertainty in wave breaking can be taken into account by considering a random variable for wave height ratio which relates the significant wave height to the maximum wave height. The proposed approach is applied numerically to the reliability analysis of caisson breakwater under wave attack that may undergo partial or full wave breaking.

  20. Enrichment of Nanodiamond Surfaces with Carboxyl Groups for Doxorubicin Loading and Release

    Science.gov (United States)

    Astuti, Y.; Saputra, F. D.; Wuning, S.; Arnelli; Bhaduri, G.

    2017-02-01

    In their pristine state, nanodiamond crystals produced via detonation techniques containing several functional groups present on the surface including amine, amide, alcohol, carbonyl, and carboxyl. These functional groups facilitate nanodiamond to interact drugs so as to nanodiamond is potential for medical application such as drug delivery. Even though research on t he use of nanodiamond for this application has been conducted widely, research on the effect of enrichment of nanodiamond surface with carboxyl functional groups for drug loading and release has not been explored extensively. Therefore, in this paper, the effect of carboxyl-terminated nanodiamond (ND-COOH) on drug loading and release will be presented. The enrichment of nanodiamond with carboxyl groups was undertaken by treating nanodiamond with sulphuric acid and nitric acid. The results show that the doxorubicin (DOX) loading and release efficiencies of ND pristine are higher than that of ND-COOH.

  1. A novel approach to generate random surface thermal loads in piping

    Energy Technology Data Exchange (ETDEWEB)

    Costa Garrido, Oriol, E-mail: oriol.costa@ijs.si; El Shawish, Samir; Cizelj, Leon

    2014-07-01

    Highlights: • Approach for generating continuous and time-dependent random thermal fields. • Temperature fields simulate fluid mixing thermal loads at fluid–wall interface. • Through plane-wave decomposition, experimental temperature statistics are reproduced. • Validation of the approach with a case study from literature. • Random surface thermal loads generation for future thermal fatigue analyses of piping. - Abstract: There is a need to perform three-dimensional mechanical analyses of pipes, subjected to complex thermo-mechanical loadings such as the ones evolving from turbulent fluid mixing in a T-junction. A novel approach is proposed in this paper for fast and reliable generation of random thermal loads at the pipe surface. The resultant continuous and time-dependent temperature fields simulate the fluid mixing thermal loads at the fluid–wall interface. The approach is based on reproducing discrete fluid temperature statistics, from experimental readings or computational fluid dynamic simulation's results, at interface locations through plane-wave decomposition of temperature fluctuations. The obtained random thermal fields contain large scale instabilities such as cold and hot spots traveling at flow velocities. These low frequency instabilities are believed to be among the major causes of the thermal fatigue in T-junction configurations. The case study found in the literature has been used to demonstrate the generation of random surface thermal loads. The thermal fields generated with the proposed approach are statistically equivalent (within the first two moments) to those from CFD simulations results of similar characteristics. The fields maintain the input data at field locations for a large set of parameters used to generate the thermal loads. This feature will be of great advantage in future sensitivity fatigue analyses of three-dimensional pipe structures.

  2. Data transmission in long-range dielectric-loaded surface plasmon polariton waveguides

    DEFF Research Database (Denmark)

    Kharitonov, S.; Kiselev, R.; Kumar, Ashwani

    2014-01-01

    We demonstrate the data transmission of 10 Gbit/s on-off keying modulated 1550 nm signal through a long-range dielectric-loaded surface plasmon polariton waveguide structure with negligible signal degradation. In the experiment the bit error rate penalties do not exceed 0.6 dB over the 15 nm...

  3. Line-focus probe excitation of Scholte acoustic waves at the liquid-loaded surfaces of periodic structures

    International Nuclear Information System (INIS)

    Every, A.G.; Vines, R.E.; Wolfe, J.P.

    1999-01-01

    A model is introduced to explain our observation of Scholte-like ultrasonic waves traveling at the water-loaded surfaces of solids with periodically varying properties. The observations pertain to two two-dimensional superlattices: a laminated solid of alternating 0.5-mm-thick layers of aluminum and a polymer, and a hexagonal array of polymer rods of lattice spacing 1 mm in an aluminum matrix. The surface waves are generated and detected by line focus acoustic lenses aligned parallel to each other, and separated by varying distances. The acoustic fields of these lenses may be considered a superposition of plain bulk waves with wave normals contained within the angular apertures of the lenses. For homogeneous solids, phase matching constraints do not allow the Scholte wave to be coupled into with an experimental configuration of this type. This is not true for a spatially periodic solid, where coupling between bulk waves and the Scholte surface wave takes place through Umklapp processes involving a change in the wave-vector component parallel to the surface by a reciprocal lattice vector. In the experiments, the source pulse is broadband, extending up to about 6 MHz, whereas the spectrum of the observed Scholte wave is peaked at around 4 and 4.5 MHz for the layered solid and hexagonal lattice, respectively. We attribute this to a resonance in the surface response of the solid, possibly associated with a critical point in the dispersion relation of the superlattice. On rotating the solid about its surface normal, the Scholte wave displays dramatic variation in phase arrival time and, to a lesser extent, also group arrival time. This variation is well accounted for by our model. copyright 1999 The American Physical Society

  4. Stoichiometric variation and loading capacity of a high-loading anammox attached film expanded bed (AAEEB) reactor.

    Science.gov (United States)

    Zhang, Yanlong; Ma, Haiyuan; Chen, Rong; Niu, Qigui; Li, Yu-You

    2018-04-01

    The nitrogen loading rate (NLR) of an anammox attached film expanded bed (AAFEB) reactor was increased from 5.0 to 60.0 gN/L/d. During the stable operational period, the TN removal efficiency maintained at 87.3 ± 2.5%, and a maximum nitrogen removal rate (NRR) of 44.9 ± 0.3 gN/L/d was achieved. Overload resulted in the sharp deterioration of reactor performance, the ratio of (Food/Microorganism)/SAA should be maintained at lower than 66 ± 7% to ensure the stable operation of the AAFEB reactor. New stoichiometric equations for the anammox process under the low NLR condition (5.0 gN/L/d) and the high NLR condition (50.0 gN/L/d) were proposed. The quantitative SAA-cytochrome heme C relationship was established for the first time that providing a simple way for monitoring the reactor performance. Substrate tolerance ability was significantly increased that proving the stability of the AAFEB reactor was continuously enhanced during the stable operational periods. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Variation in skin surface lipid composition among the Equidae.

    Science.gov (United States)

    Colton, S W; Downing, D T

    1983-01-01

    Skin surface lipids from Equus caballus, E. przewalskii, E. asinus, E. grevyi, E. hemionus onager and a mule (E. asinus/E. caballus) were analyzed in detail. In all species the surface lipid mixtures consisted of giant-ring lactones, cholesterol, cholesteryl esters and minor amounts of wax diesters. In E. caballus, the lactone hydroxyacids were entirely branched chained, while in E. asinus and E. grevyi they were almost exclusively straight chained. In E. przewalskii, the onager and the mule there were both straight and branched chain hydroxyacid lactones. These results are in harmony with published interpretations of the evolutionary relationships among Equus species.

  6. Water pollution abatement programme. The Czech Republic. Project 4.2. Assessing critical loads of acidity to surface waters in The Czech Republic. Critical loads of acidity to surface waters, Northern Moravia and Silesia, The Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Lien, L.; Raclavsky, K.; Henriksen, A.; Raclavska, H.; Matysek, D.

    1994-12-31

    The governments of Norway and Czech and Slovak Federal Republic have signed a bilateral environmental protection agreement. This report describes Project 4.2 of the agreement: Assessing critical loads of acidity to surface waters in The Czech Republic. Critical load of acidity to surface waters and exceedance of critical load were estimated by using standard methods modified for the sampling area. Water samples were mainly taken from small forest streams, which were the only available surface waters with negligible pollution from local sources. High critical loads were calculated, averaging 20 times higher than the corresponding value for southern Norway. The deposition of acidifying components in the region was high, but did not exceed the critical load and so there is a reserve for additional acid deposition. Scattered water analyses from several other parts of The Czech Republic indicate both low critical loads and exceedance of critical load in various regions (e.g. Bohemia). 21 refs., 14 figs., 3 tabs.

  7. Influence of zirconia surface treatment on veneering porcelain shear bond strength after cyclic loading.

    Science.gov (United States)

    Nishigori, Atsushi; Yoshida, Takamitsu; Bottino, Marco C; Platt, Jeffrey A

    2014-12-01

    The influence of yttria-stabilized tetragonal zirconia polycrystal surface treatment on veneering porcelain shear bond strength after cyclic loading is not fully understood. The purpose of this study was to investigate the influence of yttria-stabilized tetragonal zirconia polycrystal surface treatment on veneering porcelain shear bond strength and cyclic loading on the shear bond strength between the 2 materials. A total of 48 cylinder-shaped yttria-stabilized tetragonal zirconia polycrystal specimens were fabricated with computer-aided design and computer-aided manufacturing (CAD/CAM), sintered for 8 hours at 1500°C, ground with 320-grit diamond paper, and divided into 4 groups (n = 12) according to surface treatment as follows: no treatment/control; heat treatment of 650°C to 1000°C at 55°C/min; airborne-particle abrasion with 50-μm alumina at 0.4 MPa pressure for 10 seconds; or heat treatment after abrasion. A veneering porcelain cylinder was built and fired on the prepared yttria-stabilized tetragonal zirconia polycrystal specimens. The shear bond strength was tested with a universal testing machine. Six specimens from each group were subjected to cyclic loading (10000 cycles, 1.5 Hz, 10 N load) before testing. The mean ± SD ranged from 10.7 ± 15.4 to 34.1 ± 10.0. Three-way ANOVA found no statistically significant (P > .05) effect of surface treatment and cyclic loading on shear bond strength. The Sidak multiple comparisons procedure found that cyclic loading specimens had significantly lower shear bond strength than noncyclic loading specimens after airborne-particle abrasion without heat treatment (P = .013). Within the limitations of this study, the shear bond strength between yttria-stabilized tetragonal zirconia polycrystal and veneering porcelain was not significantly affected by surface treatment. Airborne-particle abrasion without subsequent heat treatment should be avoided as a surface treatment in fabrication methods. Copyright © 2014

  8. Effects of electric and magnetic loadings on bone surface remodeling: a model modification and simulation.

    Science.gov (United States)

    Kazerooni, Anahita Fathi; Rabbani, Mohsen; Yazdchi, Mohammadreza; Kasiri, Saeid; Rad, Hamidreza Saligheh

    2011-06-01

    This paper presents a new modification to the previous model of bone surface remodeling under electric and magnetic loadings. For this study, the thermo-electro-magneto-elastic model of bone surface remodeling is used. This model is modified by considering an important phenomenon occurring in living bone through its adaptation to external loadings called desensitization. In fact, bone cells lose their responsiveness and sensitivity to long-term external loadings, i.e., they become desensitized. Therefore, bone cells need a recovery period, during which they become resensitized. In this work, this phenomenon is considered in the original model. The effects of various electric and magnetic loading conditions, including various frequencies, waveforms and pulse duty cycles, are explored on the modified model and compared to the original model. The modified model is also searched for the optimal frequency and duty cycle, to obtain the best bone growth response under electromagnetic fields. The results of this paper show that the modified model is consistent with experimental observations. In addition, it is indicated that this modified model in contrast to the original model, is sensitive to frequency. It is shown that the optimal frequency of loading for the modified model is 1 Hertz (Hz), and the pulse duty cycles up to 50% are sufficient for bone remodeling to reach its maximum value.

  9. Stability analysis of the governor-turbine-hydraulic system of pumped storage plant during small load variation

    Science.gov (United States)

    Yu, X. D.; Zhang, J.; Chen, S.; Liu, J. C.

    2016-11-01

    Governor-turbine-hydraulic (GTH) system is complex because of strong couplings of hydraulic, mechanical and electrical system. This paper presents a convenient mathematical model of the GTH system of a pumped storage plant (PSP) during small load variation. By using state space method and eigenvalue method, the stability of the GTH system is analyzed and the stable regions of the system can be given as well, which would help to optimize system design or the turning of governors. The proposed method is used to analyze the stability of a practical pumped storage plant during small load variation, which is also simulated in time domain on the basis of characteristics method. The theoretical analysis is in good agreement with numerical simulations. Based on the proposed method, the effect of the system parameters and operating conditions on the stable regions is investigated. These results are useful for the design of the GTH system of pumped storage plants.

  10. Smart release of doxorubicin loaded on polyetheretherketone (PEEK) surface with 3D porous structure.

    Science.gov (United States)

    Ouyang, Liping; Sun, Zhenjie; Wang, Donghui; Qiao, Yuqin; Zhu, Hongqin; Ma, Xiaohan; Liu, Xuanyong

    2018-03-01

    It is important to fabricate an implant possessing environment sensitive drug delivery. In this work, the construction of 3D porous structure on polyetheretherketone (PEEK) surface and pH sensitive polymer, chitosan, was introduced. The smart release of doxorubicin can be realized on the 3D porous surface of PEEK loading chitosan. We give a feasible explanation for the effect of chitosan on smart drug release according to Henderson-Hasselbalch equation. Furthermore, the intracellular drug content of the cell cultured on the samples with highest chitosan is significantly higher at pH 4.0, whereas lower at pH 7.4 than other samples. The smart release of doxorubicin via modification with chitosan onto 3D porous PEEK surface paves the way for the application of PEEK in drug loading platform for recovering bone defect caused by malignant bone tumor. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Variation In Surface Water Vapour Density Over Four Nigerian Stations

    African Journals Online (AJOL)

    The surface water vapour density ρ has been studied using monthly averages of temperature and relative humidity at four selected weather stations in Nigeria for the years 1987 to 1991. It is found that during the dry season months of November to March, ρ is higher at night by an average of about 9.9% than during the day ...

  12. Study the Robustness Active Filter for a Three-Phase Power Rectifier Considering Line Frequency and Load Variations

    Directory of Open Access Journals (Sweden)

    Ali Jafer Mahdi

    2017-12-01

    Full Text Available Power electronic converters (e.g. AC-DC and DC-AC produce harmonics which distorting the waveforms of voltage and current. Many research works have examined various techniques to mitigate harmonics at operating conditions (i.e. at a fixed line frequency and a specific load such as: (i passive filters, (ii Current-injection converters, (iii active filters and (iv hybrid filters. Active filters are widely used with three-phase bridge rectifiers due to their excellent features for reducing harmonics using power switches instead of passive components that minimize the efficiency of the system. This paper investigates the robustness and the dynamic performance of active filters under the variation of line frequency and DC load. In case of using active filters, it is observed that total harmonic distortion (THD of voltage and current waveforms is kept at IEEE Standard limits (i.e. less than 5%  under the variation of line frequency . Whilst the performance of passive filters is highly affected by the variations of line frequency and THD of voltage and current waveforms is always greater than 5% except at designed frequency, i.e. 50 Hz. Moreover the load is changed from full-load to half-load, it is observed that the dynamic response of active filters is faster than passive filters for canceling harmonics. It is worth noting that the hysteresis-current-control method is utilized for adjusting the control pulses of active filters due to its rapid dynamic responsem. Simulation results present the highest values of THD of line currents in cases: without any filters , passive filters and active filters are 24.36%, 80.79% and 3.03%, respectively.

  13. Economic emission dispatching with variations of wind power and loads using multi-objective optimization by learning automata

    International Nuclear Information System (INIS)

    Liao, H.L.; Wu, Q.H.; Li, Y.Z.; Jiang, L.

    2014-01-01

    Highlights: • Apply multi-objective optimization by learning automata to power system. • Sequentially dimensional search and state memory are incorporated. • Track dispatch under significant variations of wind power and load demand. • Good performance in terms of accuracy, distribution and computation time. - Abstract: This paper is concerned with using multi-objective optimization by learning automata (MOLA) for economic emission dispatching in the environment where wind power and loads vary. With its capabilities of sequentially dimensional search and state memory, MOLA is able to find accurate solutions while satisfying two objectives: fuel cost coupled with environmental emission and voltage stability. Its searching quality and efficiency are measured using the hypervolume indicator for investigating the quality of Pareto front, and demonstrated by tracking the dispatch solutions under significant variations of wind power and load demand. The simulation studies are carried out on the modified midwestern American electric power system and the IEEE 118-bus test system, in which wind power penetration and load variations present. Evaluated on these two power systems, MOLA is fully compared with multi-objective evolutionary algorithm based on decomposition (MOEA/D) and non-dominated sorting genetic algorithm II (NSGA-II). The simulation results have shown the superiority of MOLA over NAGA-II and MOEA/D, as it is able to obtain more accurate and widely distributed Pareto fronts. In the dynamic environment where the operation condition of both wind speed and load demand varies, MOLA outperforms the other two algorithms, with respect to the tracking ability and accuracy of the solutions

  14. Statistical analysis of the variation of floor vibrations in nuclear power plants subject to seismic loads

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, Vilho [VTT Technical Research Centre of Finland Ltd, Kemistintie 3, 02230 Espoo (Finland); Li, Yue [Dept. of Civil Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States); Fülöp, Ludovic, E-mail: ludovic.fulop@vtt.fi [VTT Technical Research Centre of Finland Ltd, Kemistintie 3, 02230 Espoo (Finland)

    2016-12-01

    Highlights: • Floor flexibility plays a non-negligible role in amplifying horizontal vibrations. • COV of in-floor horizontal and vertical acceleration are 0.15–0.25 and 0.25–0.55. • In-floor variation of vibrations is higher in lower floors. • Floor spectra from limited nodes underestimates vibrations by a factor of 1.5–1.75. - Abstract: Floor vibration of a reactor building subjected to seismic loads was investigated, with the aim of quantifying the variability of vibrations on each floor. A detailed 3D building model founded on the bedrock was excited simultaneously in three directions by artificial accelerograms compatible with Finnish ground response spectra. Dynamic simulation for 21 s was carried out using explicit time integration. The extracted results of the simulation were acceleration in several floor locations, transformed to pseudo-acceleration (PSA) spectra in the next stage. At first, the monitored locations on the floors were estimated by engineering judgement in order to arrive at a feasible number of floor nodes for post processing of the data. It became apparent that engineering judgment was insufficient to depict the key locations with high floor vibrations, which resulted in un-conservative vibration estimates. For this reason, a more systematic approach was later considered, in which nodes of the floors were selected with a more refined grid of 2 m. With this method, in addition to the highest PSA peaks in all directions, the full vibration distribution in each floor can be determined. A statistical evaluation of the floor responses was also carried out in order to define floor accelerations and PSAs with high confidence of non-exceedance. The conclusion was that in-floor variability can be as high as 50–60% and models with sufficiently dense node grids should be used in order to achieve a realistic estimate of floor vibration under seismic action. The effects of the shape of the input spectra, damping, and flexibility of the

  15. Effectiveness of screw surface coating on the stability of zirconia abutments after cyclic loading.

    Science.gov (United States)

    Basílio, Mariana de Almeida; Butignon, Luis Eduardo; Arioli Filho, João Neudenir

    2012-01-01

    Different surface treatments have been developed in attempts to prevent the loosening of abutment screws. The aim of the current study was to compare the effectiveness of titanium alloy screws with tungsten-doped diamond-like carbon (W-DLC) coating and uncoated screws in providing stability to zirconia (ZrO2) ceramic abutments after cyclic loading. Twenty prefabricated ZrO2 ceramic abutments on their respective external-hex implants were divided into two groups of equal size according to the type of screw used: uncoated titanium alloy screw (Ti) or titanium alloy screw with W-DLC coating (W-DLC/Ti). The removal torque value (preload) of the abutment screw was measured before and after loading. Cyclic loading between 11 and 211 N was applied at an angle of 30 degrees to the long axis of the implants at a frequency of 15 Hz. A target of 0.5 X 106 cycles was defined. Group means were calculated and compared using analysis of variance and the F test (α = .05). Before cyclic loading, the preload for Ti screws was significantly higher than that for W-DLC/Ti screws (P = .021). After cyclic loading, there was no significant difference between them (P = .499). Under the studied conditions, it can be concluded that, after cyclic loading, both abutment screws presented a significant reduction in the mean retained preload and similar effectiveness in maintaining preload.

  16. Effect of counter-pulsation control of a pulsatile left ventricular assist device on working load variations of the native heart.

    Science.gov (United States)

    Choi, Seong Wook; Nam, Kyoung Won; Lim, Ki Moo; Shim, Eun Bo; Won, Yong Soon; Woo, Heung Myong; Kwak, Ho Hyun; Noh, Mi Ryoung; Kim, In Young; Park, Sung Min

    2014-04-03

    When using a pulsatile left ventricular assist device (LVAD), it is important to reduce the cardiac load variations of the native heart because severe cardiac load variations can induce ventricular arrhythmia. In this study, we investigated the effect of counter-pulsation control of the LVAD on the reduction of cardiac load variation. A ventricular electrocardiogram-based counter-pulsation control algorithm for a LVAD was implemented, and the effects of counter-pulsation control of the LVAD on the reduction of the working load variations of the left ventricle were determined in three animal experiments. Deviations of the working load of the left ventricle were reduced by 51.3%, 67.9%, and 71.5% in each case, and the beat-to-beat variation rates in the working load were reduced by 84.8%, 82.7%, and 88.2% in each ease after counter-pulsation control. There were 3 to 12 premature ventricle contractions (PVCs) before counter-pulsation control, but no PVCs were observed during counter-pulsation control. Counter-pulsation control of the pulsatile LVAD can reduce severe cardiac load variations, but the average working load is not markedly affected by application of counter-pulsation control because it is also influenced by temporary cardiac outflow variations. We believe that counter-pulsation control of the LVAD can improve the long-term safety of heart failure patients equipped with LVADs.

  17. Performance verification of focus variation and confocal microscopes measuring tilted ultra-fine surfaces

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Baruffi, Federico; Tosello, Guido

    2016-01-01

    The behaviour of two optical instruments, scilicet a laser scanning confocal microscope and a focus-variation microscope, was investigated considering measurements of tilted surfaces. The measured samples were twelve steel artefacts for mould surface finish reference, covering Sa roughness...... parameter in the range (101—103) nm. The 3D surface texture parameters considered were Sa, Sq and Sdq. The small working distance of the confocal microscope objectives influenced the measurement setup, preventing from selecting a high tilting angle. The investigation was carried out comparing measurements...... of flat surfaces (0° tilt) with measurements of 12.5° tilted surfaces. The confocal microscope results showed a high sensitivity to tilting due to the laser beam reflection on the metal surfaces. The focus variation microscope results were more robust with respect to the considered angular variation...

  18. Creep of MDF panels under constant load and cyclic environmental conditions. Influence of surface coating

    OpenAIRE

    Fernández-Golfín Seco, J. I.; Díez Barra, M. Rafael

    1997-01-01

    Four different strategies of surface coating (based on 80 g m2 melamin impregnated papers) were used on 19 mm thick commercial MDF panels to assess its reological behaviour under cyclic humidity conditions (20ºC 30 % rh-20ºC 90 % rh). Three different levels of stress (20 %, 30 % and 40 %), based on the ultimate load in bending, were used. Tests were conducted by means of the three points load system. For the same stress level, the relative creep of MDF panels was higher than that in par...

  19. Evaluation of Variation in Residual Strength of Carbon Fiber Reinforced Plastic Plate with a Hole Subjected to Fatigue Load

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Young; Kang, Min Sung; Koo, Jae Mean; Seok, Chang Sung [Sungkyunkwan University, Seoul (Korea, Republic of)

    2010-10-15

    CFRP (Carbon Fiber Reinforced Plastic) has received considerable attention in various fields as a structural material, because of its high specific strength, high specific stiffness, excellent design flexibility, favorable chemical properties, etc. Most products consisting of several parts are generally assembled by mechanical joining methods (using rivets, bolts, pins, etc.). Holes must be drilled in the parts to be joined, and the strength of the components subjected to static and fatigue loads caused by stress concentration must be decreased. In this study, we experimentally evaluated the variation in the residual strength of a holenotched CFRP plate subjected to fatigue load. We repeatedly subjected the hole-notched specimen to fatigue load for a certain number of cycles, and then we investigated the residual strength of the hole-notched specimen by performing the fracture test. From the results of the test, we can observe the initiation of a directional crack caused by the applied fatigue load. Further, we observed that the residual strength increases with a decrease in the notch effect due to this crack. It was evaluated that the residual strength increases to a certain level and subsequently decreases. This variation in the residual strength was represented by a simple equation by using a model of the decrease in residual strength for plain plate, which was developed by Reifsnider and a stress redistribution model for hole-notched plate, which was developed by Yip.

  20. Evaluation of Variation in Residual Strength of Carbon Fiber Reinforced Plastic Plate with a Hole Subjected to Fatigue Load

    International Nuclear Information System (INIS)

    Kim, Sang Young; Kang, Min Sung; Koo, Jae Mean; Seok, Chang Sung

    2010-01-01

    CFRP (Carbon Fiber Reinforced Plastic) has received considerable attention in various fields as a structural material, because of its high specific strength, high specific stiffness, excellent design flexibility, favorable chemical properties, etc. Most products consisting of several parts are generally assembled by mechanical joining methods (using rivets, bolts, pins, etc.). Holes must be drilled in the parts to be joined, and the strength of the components subjected to static and fatigue loads caused by stress concentration must be decreased. In this study, we experimentally evaluated the variation in the residual strength of a holenotched CFRP plate subjected to fatigue load. We repeatedly subjected the hole-notched specimen to fatigue load for a certain number of cycles, and then we investigated the residual strength of the hole-notched specimen by performing the fracture test. From the results of the test, we can observe the initiation of a directional crack caused by the applied fatigue load. Further, we observed that the residual strength increases with a decrease in the notch effect due to this crack. It was evaluated that the residual strength increases to a certain level and subsequently decreases. This variation in the residual strength was represented by a simple equation by using a model of the decrease in residual strength for plain plate, which was developed by Reifsnider and a stress redistribution model for hole-notched plate, which was developed by Yip

  1. Spatial correlations of interdecadal variation in global surface temperatures

    Science.gov (United States)

    Mann, Michael E.; Park, Jeffrey

    1993-01-01

    We have analyzed spatial correlation patterns of interdecadal global surface temperature variability from an empirical perspective. Using multitaper coherence estimates from 140-yr records, we find that correlations between hemispheres are significant at about 95 percent confidence for nonrandomness for most of the frequency band in the 0.06-0.24 cyc/yr range. Coherence estimates of pairs of 100-yr grid-point temperature data series near 5-yr period reveal teleconnection patterns consistent with known patterns of ENSO variability. Significant correlated variability is observed near 15 year period, with the dominant teleconnection pattern largely confined to the Northern Hemisphere. Peak-to-peak Delta-T is at about 0.5 deg, with simultaneous warming and cooling of discrete patches on the earth's surface. A global average of this pattern would largely cancel.

  2. EFFECT OF LOAD VARIATION ON LOWER MUSCLE ACTIVITY AND JOINT TORQUE DURING PARALLEL SQUATS

    OpenAIRE

    真鍋, 芳明; 横澤, 俊治; 尾縣, 貢

    2003-01-01

    The squat is used for strength training of the hip and knee joint muscles. The weight to be lifted is important for multi-joint movement like a squat, because weight differences are thought to directly affect joint load. The purpose of this study is to compare the activity of eight muscles crossing the ankle, knee and hip joints during three kinds of squats with different loads (60%, 75% and 90% of 1RM). Eight male athletes performed squats with three different loads. Variables such as net to...

  3. Effect of aerosols loading and retention on surface temperature in the DJF months

    Science.gov (United States)

    Emetere, M. E.; Onyechekwa, L.; Tunji-Olayeni, P.

    2017-05-01

    The effect of aerosols loading most often results in aerosols retention in the atmosphere. Aside the health hazards of aerosol retention, its effect on climate change are visible. In this research, it was proposed that the effect of aerosol retention also affects the fluctuation of the surface temperature. The location of study is Enugu, Nigeria (6.4584° N, 7.5464° E). Twenty-nine years GISS Surface Temperature Analysis (GISTEMP) data set and sixteen years MISR aerosol optical data set were used. The fluctuations in the sixteen years aerosol optical depth (AOD) tallied with the surface temperature. The curve-fitting tool of Matlab was used to generate a polynomial for the surface temperature and used to project a five years prediction of the surface temperature.

  4. Calculating the sensitivity of wind turbine loads to wind inputs using response surfaces

    DEFF Research Database (Denmark)

    Rinker, Jennifer M.

    2016-01-01

    at a low computational cost. Sobol sensitivity indices (SIs) can then be calculated with relative ease using the calibrated response surface. The proposed methodology is demonstrated by calculating the total sensitivity of the maximum blade root bending moment of the WindPACT 5 MW reference model to four......This paper presents a methodology to calculate wind turbine load sensitivities to turbulence parameters through the use of response surfaces. A response surface is a high-dimensional polynomial surface that can be calibrated to any set of input/output data and then used to generate synthetic data...... turbulence input parameters: a reference mean wind speed, a reference turbulence intensity, the Kaimal length scale, and a novel parameter reflecting the nonstationarity present in the inflow turbulence. The input/output data used to calibrate the response surface were generated for a previous project...

  5. Variational space–time (dis)continuous Galerkin method for nonlinear free surface water waves

    NARCIS (Netherlands)

    Gagarina, Elena; Ambati, V.R.; van der Vegt, Jacobus J.W.; Bokhove, Onno

    2014-01-01

    A new variational finite element method is developed for nonlinear free surface gravity water waves using the potential flow approximation. This method also handles waves generated by a wave maker. Its formulation stems from Miles’ variational principle for water waves together with a finite element

  6. Variational space-time (dis)continuous Galerkin method for nonlinear free surface waves

    NARCIS (Netherlands)

    Gagarina, Elena; van der Vegt, Jacobus J.W.; Ambati, V.R.; Bokhove, Onno

    A new variational finite element method is developed for nonlinear free surface gravity water waves. This method also handles waves generated by a wave maker. Its formulation stems from Miles' variational principle for water waves together with a space-time finite element discretization that is

  7. An experimental study on mass loading of soil particles on plant surfaces

    International Nuclear Information System (INIS)

    Li, J.; Gerzabek, M.H.; Mueck, K.

    1994-03-01

    Radionuclide contaminated soil adhered to plant surfaces can contribute to human ingestion dose. To determine this contribution, a method of 46 Sc neutron activation analysis was established and tested, by which a detection limit of 0.05 mg soil per g dry plant biomass can be obtained. In the field and greenhouse experiment the mass loading of soil on ryegrass (Lolium perenne L.) and broad bean (Vicia faba L.) was investigated and the contribution from rainsplash and wind erosion were evaluated separately. Soil retained on plant surfaces in field conditions in Seibersdorf/Austria was 5.77 ± 1.44 mg soil per g dry plant for ryegrass and 9.51 ± 0.73 mg soil per g dry plant for broad bean. Estimates of contribution from rainsplash and wind erosion to soil contamination of plant during the experimental period are 68 % and 32 % for broadbean, 47 % and 53 % for ryegrass, respectively. Mass loading results from field studies indicate that soil adhesion on plant surfaces can contribute up to 23 % of plant 137 Cs contamination, the transfer factors modified by mass loading decline differently, depending on 137 Cs concentration of the soil and the soil mass adhered to plant surfaces. (authors)

  8. An experimental study on mass loading of soil particles on plant surfaces

    International Nuclear Information System (INIS)

    Li, J. G.; Gerzabek, M. H.; Mueck, K.

    1994-01-01

    Radionuclide contaminated soil adhered to plant surfaces can contribute to human ingestion dose. To determine this contribution, a method of 46 Sc neutron activation analysis was established and tested, by which a detection limit of 0.05 mg soil per g dry plant biomass can be obtained. In the field and greenhouse experiment the mass loading of soil on ryegrass (Lolium perenne L.) and broadbean (Vicia faba L.) was investigated and the contribution from rainsplash and wind erosion were evaluated separately. Soil retained on plant surfaces in field conditions in Seibersdorf/Austria was 5.77 ± 1.44 mg soil per g dry plant for ryegrass and 9.51 ± 0.73 mg soil per g dry plant for broadbean. Estimates of contribution from rainsplash and wind erosion to soil contamination of plants during the experimental period are 68 % and 32 % for broadbean 47 % and 53 % for ryegrass respectively. Mass loading results from field studies indicate that soil adhesion on plant surfaces can contribute up to 23 % of plant 137 Cs contamination, the transfer factors modified by mass loading decline differently, depending on 137 Cs concentration of the soil and the soil mass adhered to plant surfaces. (author)

  9. Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces

    Science.gov (United States)

    Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

    2017-05-01

    For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ˜26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad.

  10. Mechanical stability of immediately loaded implants with various surfaces and designs: a pilot study in dogs.

    Science.gov (United States)

    Neugebauer, Jörg; Weinländer, Michael; Lekovic, Vojislav; von Berg, Karl-Heinz Linne; Zoeller, Joachim E

    2009-01-01

    Immediate loading is among the most innovative techniques in implant therapy today. This pilot study investigates the biomechanical outcome of various designs and surfaces that claim to shorten implant treatment. In each quadrant of two mongrel dogs, four different implants were used for immediate loading. The following implants were placed 3 months after tooth extraction: screw with low thread profile and anodic oxidized surface (LPAOS), solid screw with wide thread profile and titanium plasma spray coating (WPTPS), screw with low profile and hybrid design of double-etched and machined surface (LPHES), and screw with two thread profiles and a sandblasted and acid-etched surface (DTSAE). The insertion torque of each implant was above 35 Ncm. Resonance frequency analysis was performed after implant placement and again after sacrifice. Additionally, the removal torque and the amount of embedded titanium particles in the peri-implant bone were measured. All 16 prostheses were functional after a 5-month loading period. The highest mean removal torque values were recorded with WPTPS implants (24.4 Ncm/mm), followed by DTSAE implants (22.3 Ncm/mm) and LPAOS implants (18.7 Ncm/mm); the lowest score was obtained by LPHES (12.0 Ncm/mm). The ISQ values increased between the time of surgery and recall for all systems on average, but a significant positive correlation was found for DTSAE only. Significantly higher amounts of titanium were found in the surrounding bone with WPTPS (0.76%) and LPAOS (0.41%) in comparison with DTSAE (0.10%) and LPHES (0.03%). Immediate loading is possible with various designs and surfaces if high primary stability can be achieved during implant placement.

  11. A Framework for Dynamic Modeling of Surface-Structure Patches on Bed Load Transport in Coarse Grained Reaches

    Science.gov (United States)

    Strom, K. B.

    2010-12-01

    Mountain streams are the first link in the fluvial system and often have complex bed morphologies which make it difficult to develop simple quantitative expressions for sediment mass flux and stream flow resistance. Such expressions are important for landscape evolution modeling as well as stream management and restoration practices and efforts. Part of the difficulty lies in the fact that stream beds can have large variations in particle size and structural organization - both of which lead to variations in bed strength that can change as a function of time. This study presents a mathematical framework to account for the dynamic impact of surface-structure patches on bed strength and bed load transport under simplified conditions. The framework is based on conservation principles for tracking the exchange of mass between structured and unstructured surface patches in the bed during structure formation and breakup. Two main transport equations are solved for the mobile and stationary phases, and the exchange between the two is modeled using particle collision theory and a simple breakup model (figure 1). The experiments of Strom et al. (2004) are used to parameterize the model initial conditions, and calculated and experimentally observed transport rates are compared as a function of time. Conceptual sketch of the modeling framework for: (A) a gravel bed, and (B) an idealized bed of uniform spherical particles. Mass conservation equations are written for each phase (structured and unstructured) and then solved with time under varying conditions.

  12. Variation in ectoparasite load in the Mehely's horseshoe bat, Rhinolophus mehelyi (Chiroptera: Rhinolophidae) in a nursery colony in western Iran.

    Science.gov (United States)

    Sharifi, Mozafar; Taghinezhad, Najmeh; Mozafari, Fatema; Vaissi, Somaye

    2013-06-01

    We studied variation of ectoparasite load in a free ranging populations of Mehely's horseshoe bat (Rhinolophus mehelyi) on five successive occasions in a nursery roost in western Iran. In total, 87 Rhinolophus mehelyi were captured. The patterns of abundance differed greatly among parasite species but total parasite load was markedly higher in pregnant females in spring and early summer and lower in solitary males. On average, 90% of bats were infested by Eyndhovenia sp. with a mean intensity of 13.79 individuals per bat. Penicillidia sp. and one species from Streblidae were found in 66.7% and 11.49% of bats with parasite load of 2.31 and 1.8 parasite per bat, respectively. Using ratio of forearm length to body mass as an indication of bat health the correlation coefficient between parasite load and the health indicator was 0.002 for males and 0.06 for females indicating that parasite load has no apparent impact on bat's health.

  13. Design of sampling locations for river water quality monitoring considering seasonal variation of point and diffuse pollution loads.

    Science.gov (United States)

    Varekar, Vikas; Karmakar, Subhankar; Jha, Ramakar; Ghosh, N C

    2015-06-01

    The design of a water quality monitoring network (WQMN) is a complicated decision-making process because each sampling involves high installation, operational, and maintenance costs. Therefore, data with the highest information content should be collected. The effect of seasonal variation in point and diffuse pollution loadings on river water quality may have a significant impact on the optimal selection of sampling locations, but this possible effect has never been addressed in the evaluation and design of monitoring networks. The present study proposes a systematic approach for siting an optimal number and location of river water quality sampling stations based on seasonal or monsoonal variations in both point and diffuse pollution loadings. The proposed approach conceptualizes water quality monitoring as a two-stage process; the first stage of which is to consider all potential water quality sampling sites, selected based on the existing guidelines or frameworks, and the locations of both point and diffuse pollution sources. The monitoring at all sampling sites thus identified should be continued for an adequate period of time to account for the effect of the monsoon season. In the second stage, the monitoring network is then designed separately for monsoon and non-monsoon periods by optimizing the number and locations of sampling sites, using a modified Sanders approach. The impacts of human interventions on the design of the sampling net are quantified geospatially by estimating diffuse pollution loads and verified with land use map. To demonstrate the proposed methodology, the Kali River basin in the western Uttar Pradesh state of India was selected as a study area. The final design suggests consequential pre- and post-monsoonal changes in the location and priority of water quality monitoring stations based on the seasonal variation of point and diffuse pollution loadings.

  14. Investigation into Mass Loading Sensitivity of Sezawa Wave Mode-Based Surface Acoustic Wave Sensors

    Directory of Open Access Journals (Sweden)

    N. Ramakrishnan

    2013-02-01

    Full Text Available In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW device is investigated through finite element method (FEM simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

  15. Variations of Polymer Porous Surface Structures via the Time-Sequenced Dosing of Mixed Solvents.

    Science.gov (United States)

    Wrzecionko, Erik; Minařík, Antonín; Smolka, Petr; Minařík, Martin; Humpolíček, Petr; Rejmontová, Petra; Mráček, Aleš; Minaříková, Magda; Gřundělová, Lenka

    2017-02-22

    A new approach to polystyrene surface treatment via the time-sequenced dispensing of good and poor solvent mixtures on the rotating surface of treated substrate is presented in this study. It is demonstrated that the variation of the sequencing together with other variables (e.g., temperature and solvent concentration) affects the size and depth of pores evolving on the polystyrene surface. A model of the surface pore creation, associated with the viscoelastic phase separation, surface tension, and secondary flows caused by temperature variations and the rapid evaporation of the good solvent is proposed. Experimental results of profilometric, goniometric, and optical measurements show that this approach enables the simple and quick preparation of surfaces with various numbers, diameters, and depths of individual pores, which ultimately affects not only the wetting characteristics of the surfaces but also the fate of cells cultivated there. The presented method allows the easy preparation of a large number of structured substrates for effective cell cultivation and proliferation.

  16. Core surface flow modelling from high-resolution secular variation

    DEFF Research Database (Denmark)

    Holme, R.; Olsen, Nils

    2006-01-01

    -flux hypothesis, but the spectrum of the SV implies that a conclusive test of frozen-flux is not possible. We parametrize the effects of diffusion as an expected misfit in the flow prediction due to departure from the frozen-flux hypothesis; at low spherical harmonic degrees, this contribution dominates...... the expected departure of the SV predictions from flow to the observed SV, while at high degrees the SV model uncertainty is dominant. We construct fine-scale core surface flows to model the SV. Flow non-uniqueness is a serious problem because the flows are sufficiently small scale to allow flow around non......-series of magnetic data and better parametrization of the external magnetic field....

  17. Coupling characteristics of dielectric-loaded surface plasmon polariton waveguides: a simple method of analysis.

    Science.gov (United States)

    Srivastava, Triranjita; Kumar, Arun

    2009-11-01

    A simple method to obtain the coupling characteristics of a directional coupler consisting of two dielectric-loaded surface plasmon polariton waveguides is reported. The method is found to give accurate results in comparison with the widely used effective index method. Theoretical results are also found to match excellently with recently reported measurements on coupling lengths in such waveguides [Opt. Lett.34, 310 (2009)OPLEDP0146-959210.1364/OL.34.000310].

  18. Continental-scale water fluxes from continuous GPS observations of Earth surface loading

    Science.gov (United States)

    Borsa, A. A.; Agnew, D. C.; Cayan, D. R.

    2015-12-01

    After more than a decade of observing annual oscillations of Earth's surface from seasonal snow and water loading, continuous GPS is now being used to model time-varying terrestrial water fluxes on the local and regional scale. Although the largest signal is typically due to the seasonal hydrological cycle, GPS can also measure subtle surface deformation caused by sustained wet and dry periods, and to estimate the spatial distribution of the underlying terrestrial water storage changes. The next frontier is expanding this analysis to the continental scale and paving the way for incorporating GPS models into the National Climate Assessment and into the observational infrastructure for national water resource management. This will require reconciling GPS observations with predictions from hydrological models and with remote sensing observations from a suite of satellite instruments (e.g. GRACE, SMAP, SWOT). The elastic Earth response which transforms surface loads into vertical and horizontal displacements is also responsible for the contamination of loading observations by tectonic and anthropogenic transients, and we discuss these and other challenges to this new application of GPS.

  19. Effect of Cyclic Loading on Surface Instability of Silicone Rubber under Compression

    Directory of Open Access Journals (Sweden)

    Zhonglin Li

    2017-04-01

    Full Text Available This work combines experiments and finite element simulations to study the effect of pre-imposed cyclic loading on surface instability of silicon rubber under compression. We first fabricate cuboid blocks of silicon rubber and pinch them cyclicly a few times. Then, an in-house apparatus is set to apply uniaxial compression on the silicon rubber under exact plane strain conditions. Surprisingly, we find multiple creases on the surface of silicone rubber, significantly different from what have been observed on the samples without the cyclic pinching. To reveal the underlying physics for these experimentally observed multiple creases, we perform detailed nanoindentation experiments to measure the material properties at different locations of the silicon rubber. The modulus is found to be nonuniform and varies along the thickness direction after the cyclic pinching. According to these experimental results, three-layer and multilayer finite element models are built with different materials properties informed by experiments. The three-layer finite element model can excellently explain the nucleation and pattern of multiple surface creases on the surface of compressed silicone rubber, in good agreement with experiments. Counterintuitively, the multilayer model with gradient modulus cannot be used to explain the multiple creases observed in our experiments. According to these simulations, the experimentally observed multiple creases should be attributed to a thin and stiff layer formed on the surface of silicon rubber after the pre-imposed cyclic loading.

  20. Analysis of chiller units capacity for different heat loads considering variation of ambient air and cooling water temperature

    International Nuclear Information System (INIS)

    Coman, Aurelia Camelia; Tenescu, Mircea

    2010-01-01

    The paper purpose is to analyze the chiller units capacity to determine whether they can cope with high air and cooling water temperatures during summer time to remove heat loads imposed from Heating, Ventilation and Air Conditioning (HVAC) units in a CANDU 6 Nuclear Power Plant. The starting point is calculation of the overall heat transfer coefficient at the evaporator and condenser. They are used in heat balance equations of heat exchangers. A mathematical model was developed that simulates the refrigeration cycle to assess the response of chilled water system and its performance at different heat loads. In this analysis there were calculated values for inlet/outlet chilled water temperature and the refrigerant cycle thermodynamic parameters (condenser and evaporator pressure/temperature, refrigerant mass flowrate, refrigerant quality at the evaporator, refrigerant vapour superheated temperature at the compressor outlet, refrigerant subcooled temperature at the condenser outlet). To find the adequate functioning parameters of the installation, the MathCAD 13 software was used in all cases analyzed. The behaviour of the chiller units was investigated by examining the variation of three basic parameters, namely: - cooling water (river water) temperature; - air temperature; - heat load. The simultaneous variation of these three independent parameters allows to identify the actual chillers unit operating point (including chiller trip). (authors)

  1. Surface pressure and aerodynamic loads determination of a transonic airfoil based on particle image velocimetry

    International Nuclear Information System (INIS)

    Ragni, D; Ashok, A; Van Oudheusden, B W; Scarano, F

    2009-01-01

    The present investigation assesses a procedure to extract the aerodynamic loads and pressure distribution on an airfoil in the transonic flow regime from particle image velocimetry (PIV) measurements. The wind tunnel model is a two-dimensional NACA-0012 airfoil, and the PIV velocity data are used to evaluate pressure fields, whereas lift and drag coefficients are inferred from the evaluation of momentum contour and wake integrals. The PIV-based results are compared to those derived from conventional loads determination procedures involving surface pressure transducers and a wake rake. The method applied in this investigation is an extension to the compressible flow regime of that considered by van Oudheusden et al (2006 Non-intrusive load characterization of an airfoil using PIV Exp. Fluids 40 988–92) at low speed conditions. The application of a high-speed imaging system allows the acquisition in relatively short time of a sufficient ensemble size to compute converged velocity statistics, further translated in turbulent fluctuations included in the pressure and loads calculation, notwithstanding their verified negligible influence in the computation. Measurements are performed at varying spatial resolution to optimize the loads determination in the wake region and around the airfoil, further allowing us to assess the influence of spatial resolution in the proposed procedure. Specific interest is given to the comparisons between the PIV-based method and the conventional procedures for determining the pressure coefficient on the surface, the drag and lift coefficients at different angles of attack. Results are presented for the experiments at a free-stream Mach number M = 0.6, with the angle of attack ranging from 0° to 8°

  2. The effect on road load due to variations in valid coast down tests for passenger cars

    NARCIS (Netherlands)

    Mensch, P. van; Ligterink, N.E.; Cuelenaere, R.F.A.

    2014-01-01

    Real-world CO2 emissions of passenger cars very often deviate from the Type Approval value. The Type Approval value for CO2 emissions of passenger cars is based on a chassis dynamometer test in a laboratory. The total vehicle resistance of a vehicle, or 'road load', is simulated on the chassis

  3. Study on Power Loss Reduction Considering Load Variation with Large Penetration of Distributed Generation in Smart Grid

    Science.gov (United States)

    Liu, Chang; Lv, Xiangyu; Guo, Li; Cai, Lixia; Jie, Jinxing; Su, Kuo

    2017-05-01

    With the increasing of penetration of distributed in the smart grid, the problems that the power loss increasing and short circuit capacity beyond the rated capicity of circuit breaker will become more serious. In this paper, a methodology (Modified BPSO) is presented for network reconfiguration which is based on hybrid approach of Tabu Search and BPSO algorithms to prevent the local convergence and to decrease the calculation time using double fitnesses to consider the constraints. Moreover, an average load simulated method (ALS method) load variation considered is proposed that the average load value is used to instead of the actual load to calculation. Finally, from a case study, the results of simulation certify the approaches will decrease drastically the losses and improve the voltage profiles obviously, at the same time, the short circuit capacity is also decreased into less the shut-off capacity of circuit breaker. The power losses won’t be increased too much even if the short circuit capacity constraint is considered; voltage profiles are better with the constraint of short circuit capacity considering. The ALS method is simple and calculated time is speed.

  4. Control of a post-combustion CO2 capture plant during process start-up and load variations

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Jørgensen, John Bagterp; Fosbøl, Philip Loldrup

    2015-01-01

    capture. The study demonstrates that the implemented control structure keeps the carbon capture process at 90% CO2 removal rate with a deviation up to 8% during load variations. In addition, it reveals that the control structure brings the process to the desired set point in approximately 10 min during...... and control system design are crucial. In this paper, we present a dynamic mathematical model for the absorption and desorption columns in a carbon capture plant. Moreover, we implement a decentralized proportional-integral (PI) based control scheme and we evaluate the performance of the control structure...... for various operational procedures, e.g. start-up, load changes, noise on the flue gas flow rate and composition. Note that the carbon capture plant is based on the solvent storage configuration. To the authors knowledge, this is the first paper addressing the issue of start-up operation and control of carbon...

  5. Spatial variation of atmospheric nitrogen deposition and critical loads for aquatic ecosystems in the Greater Yellowstone Area.

    Science.gov (United States)

    Nanus, L; McMurray, J A; Clow, D W; Saros, J E; Blett, T; Gurdak, J J

    2017-04-01

    Current and historic atmospheric nitrogen (N) deposition has impacted aquatic ecosystems in the Greater Yellowstone Area (GYA). Understanding the spatial variation in total atmospheric deposition (wet + dry) of N is needed to estimate air pollution deposition critical loads for sensitive aquatic ecosystems. This is particularly important for areas that have an increasing contribution of ammonia dry deposition to total N (TN), such as the GYA. High resolution geostatistical models and maps of TN deposition (wet + dry) were developed using a variety of techniques including ordinary kriging in a geographic information system, to evaluate spatial variability and identify areas of elevated loading of pollutants for the GYA. TN deposition estimates in the GYA range from models and maps can be used to help identify and protect sensitive ecosystems that may be impacted by excess atmospheric N deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Inter-annual variations in water yield to lakes in northeastern Alberta: implications for estimating critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Roderick HAZEWINKEL

    2010-08-01

    Full Text Available Stable isotopes of water were applied to estimate water yield to fifty lakes in northeastern Alberta as part of an acid sensitivity study underway since 2002 in the Athabasca Oil Sands Region (AOSR. Herein, we apply site-specific water yields for each lake to calculate critical loads of acidity using water chemistry data and a steady-state water chemistry model. The main goal of this research was to improve site-specific critical load estimates and to understand the sensitivity to hydrologic variability across a Boreal Plains region under significant oil sands development pressure. Overall, catchment water yields were found to vary significantly over the seven year monitoring period, with distinct variations among lakes and between different regions, overprinted by inter-annual climate-driven shifts. Analysis of critical load estimates based on site-specific water yields suggests that caution must be applied to establish hydrologic conditions and define extremes at specific sites in order to protect more sensitive ecosystems. In general, lakes with low (high water yield tended to be more (less acid sensitive but were typically less (more affected by interannual hydrological variations. While it has been customary to use long-term water yields to define a static critical load for lakes, we find that spatial and temporal variability in water yield may limit effectiveness of this type of assessment in areas of the Boreal Plain characterized by heterogeneous runoff and without a long-term lake-gauging network. Implications for predicting acidification risk are discussed for the AOSR.

  7. Eradication of high viable loads of Listeria monocytogenes contaminating food-contact surfaces

    Directory of Open Access Journals (Sweden)

    Silvia ede Candia

    2015-07-01

    Full Text Available This study demonstrates the efficacy of cold gaseous ozone treatments at low concentrations in the eradication of high Listeria monocytogenes viable cell loads from glass, polypropylene, stainless steel and expanded polystyrene food-contact surfaces. Using a step by step approach, involving the selection of the most resistant strain-surface combinations, 11 Listeria spp. strains resulted inactivated by a continuous ozone flow at 1.07 mg m-3 after 24 or 48 h of cold incubation, depending on both strain and surface evaluated. Increasing the inoculum level to 9 log CFU coupon-1, the best inactivation rate was obtained after 48h of treatment at 3.21 mg m-3 ozone concentration when cells were deposited onto stainless steel and expanded polystyrene coupons, resulted the most resistant food-contact surfaces in the previous assays.The addition of naturally microbiologically contaminated meat extract to a high load of L. monocytogenes LMG 23775 cells, the most resistant strain out of the 11 assayed Listeria spp. strains, led to its complete inactivation after four days of treatment.To the best of our knowledge, this is the first report describing the survival of L. monocytogenes and the effect of ozone treatment under cold storage conditions on expanded polystyrene, a commonly-used material in food packaging. These results could be useful for reducing pathogen cross-contamination phenomena during cold food storage.

  8. Photocatalytic activity of PANI loaded coordination polymer composite materials: Photoresponse region extension and quantum yields enhancement via the loading of PANI nanofibers on surface of coordination polymer

    International Nuclear Information System (INIS)

    Cui, Zhongping; Qi, Ji; Xu, Xinxin; Liu, Lu; Wang, Yi

    2013-01-01

    To enhance photocatalytic property of coordination polymer in visible light region, polyaniline (PANI) loaded coordination polymer photocatalyst was synthesized through in-situ chemical oxidation of aniline on the surface of coordination polymer. The photocatalytic activity of PANI loaded coordination polymer composite material for degradation of Rhodamine B (RhB) was investigated. Compared with pure coordination polymer photocatalyst, which can decompose RhB merely under UV light irradiation, PANI loaded coordination polymer photocatalyst displays more excellent photocatalytic activity in visible light region. Furthermore, PANI loaded coordination polymer photocatalyst exhibits outstanding stability during the degradation of RhB. - Graphical abstract: PANI loaded coordination polymer composite material, which displays excellent photocatalytic activity under visible light was firstly synthesized through in-situ chemical oxidation of aniline on surface of coordination polymer. Display Omitted - Highlights: • This PANI loaded coordination polymer composite material represents the first conductive polymer loaded coordination polymer composite material. • PANI/coordination polymer composite material displays more excellent photocatalytic activity for the degradation of MO in visible light region. • The “combination” of coordination polymer and PANI will enable us to design high-activity, high-stability and visible light driven photocatalyst in the future

  9. Surface modification and fatigue behavior of nitinol for load bearing implants

    Science.gov (United States)

    Bernard, Sheldon A.

    Musculoskeletal disorders are recognized amongst the most significant human health problems that exist today. Even though considerable research and development has gone towards understanding musculoskeletal disorders, there is still lack of bone replacement materials that are appropriate for restoring lost structures and functions, particularly for load-bearing applications. Many materials on the market today, such as titanium and stainless steel, suffer from significantly higher modulus than natural bone and low bioactivity leading to stress shielding and implant loosening over longer time use. Nitinol (NiTi) is an equiatomic intermetallic compound of nickel and titanium whose unique biomechanical and biological properties contributed to its increasing use as a biomaterial. An innovative method for creating dense and porous net shape NiTi alloy parts has been developed to improve biological properties while maintaining comparable or better mechanical properties than commercial materials that are currently in use. Laser engineered net shaping (LENS(TM)) and surface electrochemistry modification was used to create dense/porous samples and micro textured surfaces on NiTi parts, respectively. Porous implants are known to promote cell adhesion and have a low elastic modulus, a combination that can significantly increase the life of an implant. However, porosity can significantly reduce the fatigue life of an implant, and very little work has been reported on the fatigue behavior of bulk porous metals, specifically on porous nitinol alloy. High-cycle rotating bending and compression-compression fatigue behavior of porous NiTi fabricated using LENS(TM) were studied. In cyclic compression loading, plastic strain increased with increasing porosity and it was evident that maximum strain was achieved during the first 50000 cycles and remained constant throughout the remaining loading. No failures were observed due to loading up to 150% of the yield strength. When subjected

  10. Surface adhesion and confinement variation of Staphylococcus aurius on SAM surfaces

    Science.gov (United States)

    Amroski, Alicia; Olsen, Morgan; Calabrese, Joseph; Senevirathne, Reshani; Senevirathne, Indrajith

    2012-02-01

    Controlled surface adhesion of non - pathogenic gram positive strain, Staphylococcus aureus is interesting as a model system due to possible development of respective biosensors for prevention and detection of the pathogenic strain methicillin resistant Staphylococcus aureus (MRSA) and further as a study for bio-machine interfacing. Self Assembled Monolayers (SAM) with engineered surfaces of linear thiols on Au(111) were used as the substrate. Sub cultured S. aureus were used for the analysis. The SAM layered surfaces were dipped in 2 -- 4 Log/ml S. aureus solution. Subsequent surface adhesion at different bacterial dilutions on surfaces will be discussed, and correlated with quantitative and qualitative adhesion properties of bacteria on the engineered SAM surfaces. The bacteria adhered SAM surfaces were investigated using intermittent contact, noncontact, lateral force and contact modes of Atomic Force Microscopy (AFM).

  11. Limit load estimation method for pipe with an arbitrary shaped circumferential surface flaw

    International Nuclear Information System (INIS)

    Li, Yinsheng; Hasegawa, Kunio; Onizawa, Kunio; Sugino, Hideharu

    2009-01-01

    When a flaw is detected in a stainless steel pipe during in-service inspection, the limit load criterion given in the codes such as JSME Rules on Fitness-for-Service for Nuclear Power Plants or ASME Boiler and Pressure Vessel Code Section XI can be applied to evaluate the integrity of the pipe. However, in the present codes, the limit load criterion is only provided for the case of a flaw with the uniform depth, although many flaws with complicated shape such as stress corrosion cracking have been actually detected in a pipe. In this paper, a limit load estimation method is proposed considering a circumferential flaw with arbitrary shape, in order to make it possible to evaluate the integrity of the pipe for general case. The plastic collapse moment and stress are obtained by dividing the surface flaw into several segmented sub-flaws. Using this method, good agreement is observed between the numerical solution and reported experimental results. Several numerical examples are also given to show the validity of this method. Finally, it can be seen that the number of the segmented sub-flaws for the semi-elliptical surface flaw is sufficient to be three from engineering judgment. (author)

  12. Water pollution abatement programme. The Czech Republic. Project 4.2. Assessing critical loads of acidity to surface waters in the Czech Republic. Critical loads of acidity to surface waters, north-eastern Bohemia and northern Moravia, The Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Lien, L.; Raclavsky, K.; Raclavska, H.; Matysek, D.; Hovind, H.

    1996-01-01

    This report discusses estimates of critical loads of acidity to surface waters and their exceedances, for north-eastern Bohemia and Moravia in The Czech Republic. The survey covers 13 400 km{sup 2}, or 17% of the area of the country. Varying critical loads were observed within the examined region. 19% of the examined area showed exceedance of critical load and another 11% was close to exceedance. The survey should continue in Bohemia. 24 refs., 20 figs., 4 tabs.

  13. Guaranteed and computable bounds of the limit load for variational problems with linear growth energy functionals

    Czech Academy of Sciences Publication Activity Database

    Haslinger, Jaroslav; Repin, S.; Sysala, Stanislav

    2016-01-01

    Roč. 61, č. 5 (2016), s. 527-564 ISSN 0862-7940 R&D Projects: GA MŠk LQ1602 Institutional support: RVO:68145535 Keywords : functionals with linear growth * limit load * truncation method * perfect plasticity Subject RIV: BA - General Mathematics Impact factor: 0.618, year: 2016 http://link.springer.com/article/10.1007/s10492-016-0146-6

  14. Effect of loading rate variation on soybean protein wastewater treatment by UASB reactor

    Science.gov (United States)

    Sun, Yi; Li, Yongfeng; Guo, Zi-rui; Jiao, An-ying; Han, Wei; Yang, Chuan-ping

    2010-11-01

    In order to improve the efficiency and evaluate the feasibility of anaerobic digestion for treatment of soybean protein wastewater. The stability and performance of the Up-Flow Anaerobic Sludge Blanket (UASB) process was investigated at different organic loading rates (OLRS) and hydraulic retention times over 200 days. When chemical oxygen demand (COD) reached maximum, the loading rate was adjusted in a small way and indicators such as VFA, pH and COD in effluent as well as gas production are observed. These experimental results clearly showed that, the most proper corresponding organic loading rate (OLR) and hydraulic retention time were 6 kg/ (m3ṡd) (COD = 6000 mg/L) and 24 h respectively. Up to 85% of COD was removed and the CH4 production rate of 3.2 m3/(m3ṡd) was obtained. The produced biogas contained 72% of CH4. In the mean time, anaerobic sludge multiplies more faster and exiguous particles appeared. Granules with diameter 1-3 mm.

  15. Lateral Viscosity Variations in the Both Local and Global and Viscoelastic Load Response and it's Uncertainty

    Science.gov (United States)

    Ivins, E. R.; Caron, L.; Adhikari, S.; Larour, E. Y.; Seroussi, H. L.; Wiens, D.; Lloyd, A. J.; Dietrich, R. O. R.; Richter, A.

    2017-12-01

    One aspect of GIA modeling that has been a source of contention for many years is the exploration, or lack thereof, of the parameters representing growth and collapse of ice loading while additionally allowing mantle structure to vary. These problems are today being approached with advanced coupled solid earth and ice sheet continuum mechanics. An additional source of non-uniqueness lies in the potential for large (4 orders of magnitude) variability in mantle creep strength. A main question that remains is how to seek some simplification of the set of problems that this implies and to shed from consideration those questions that lack relevance to properly interpreting geodetic data sets. Answering this question therefore entails defining what science questions are to be addressed and to define what parameters produce the highest sensitivities. Where mantle viscosity and lithospheric thickness have affinity with an active dynamic mantle that brings rejuvenation by upwelling of volatiles and heat, the time scales for ice and water loading shorten. Here we show how seismic images map with constitutive flow laws into effective laterally varying viscosity maps. As important, we map the uncertainties. In turn, these uncertainties also inform the time scales that are sensitive to load reconstruction for computing present-day deformation and gravity. We employ the wavelength-dependent viscoelastic response decay spectra derived from analytic solutions in order to quantitatively map these sensitivities.

  16. Observations on the effects of grooved surfaces on the interfacial torque in highly loaded rolling and sliding tests

    DEFF Research Database (Denmark)

    Janakiraman, Shravan; Klit, Peder; Jensen, Niels Steenfeldt

    2014-01-01

    Some efforts have been undertaken to study the effects of grooved surfaces on the interfacial film thickness and torque between two contacting non-conformal surfaces under heavy loads. Transverse grooves of micrometer scale depth were engraved on polished, flat ring surfaces using established...... industrial methods like laser engraving and wire cutting. The grooved surfaces were then run against a polished flat surface at loads corresponding to high normal Hertzian pressures. Experiments were conducted to study the effects of the following parameters on the interfacial torque-groove depth, groove...

  17. Sodium Dodecyl Sulfate (SDS)-Loaded Nanoporous Polymer as Anti-Biofilm Surface Coating Material

    Science.gov (United States)

    Li, Li; Molin, Soeren; Yang, Liang; Ndoni, Sokol

    2013-01-01

    Biofilms cause extensive damage to industrial settings. Thus, it is important to improve the existing techniques and develop new strategies to prevent bacterial biofilm formation. In the present study, we have prepared nanoporous polymer films from a self-assembled 1,2-polybutadiene-b-polydimethylsiloxane (1,2-PB-b-PDMS) block copolymer via chemical cross-linking of the 1,2-PB block followed by quantitative removal of the PDMS block. Sodium dodecyl sulfate (SDS) was loaded into the nanoporous 1,2-PB from aqueous solution. The SDS-loaded nanoporous polymer films were shown to block bacterial attachment in short-term (3 h) and significantly reduce biofilm formation in long-term (1 week) by gram-negative bacterium Escherichia coli. Tuning the thickness or surface morphology of the nanoporous polymer films allowed to extent the anti-biofilm capability. PMID:23377015

  18. Sodium Dodecyl Sulfate (SDS-Loaded Nanoporous Polymer as Anti-Biofilm Surface Coating Material

    Directory of Open Access Journals (Sweden)

    Sokol Ndoni

    2013-02-01

    Full Text Available Biofilms cause extensive damage to industrial settings. Thus, it is important to improve the existing techniques and develop new strategies to prevent bacterial biofilm formation. In the present study, we have prepared nanoporous polymer films from a self-assembled 1,2-polybutadiene-b-polydimethylsiloxane (1,2-PB-b-PDMS block copolymer via chemical cross-linking of the 1,2-PB block followed by quantitative removal of the PDMS block. Sodium dodecyl sulfate (SDS was loaded into the nanoporous 1,2-PB from aqueous solution. The SDS-loaded nanoporous polymer films were shown to block bacterial attachment in short-term (3 h and significantly reduce biofilm formation in long-term (1 week by gram-negative bacterium Escherichia coli. Tuning the thickness or surface morphology of the nanoporous polymer films allowed to extent the anti-biofilm capability.

  19. Variation of Loads on Offshore Wind Turbine Drivetrains During Measured Shutdown Events

    DEFF Research Database (Denmark)

    Natarajan, Anand

    2016-01-01

    -megawatt wind turbine located at an offshore wind farm are correlated with corresponding observations of shutdowns on surrounding wind turbines. The observed wind turbines have multiple shutdowns at high mean wind speeds due to wind speed variations near cut-out. Through the use of an Inverse First Order...

  20. Intrinsic Charge Trapping Observed as Surface Potential Variations in diF-TES-ADT Films.

    Science.gov (United States)

    Hoffman, Benjamin C; McAfee, Terry; Conrad, Brad R; Loth, Marsha A; Anthony, John E; Ade, Harald W; Dougherty, Daniel B

    2016-08-24

    Spatial variations in surface potential are measured with Kelvin probe force microscopy for thin films of 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophenes (diF-TES-ADT) grown on SiO2 and silane-treated SiO2 substrates by organic molecular beam deposition. The variations are observed both between and within grains of the polycrystalline organic film and are quantitatively different than electrostatic variations on the substrate surfaces. The skewness of surface potential distributions is larger on SiO2 than on HMDS-treated substrates. This observation is attributed to the impact of substrate functionalization on minimizing intrinsic crystallographic defects in the organic film that can trap charge.

  1. In-situ imaging of tungsten surface modification under ITER-like transient heat loads

    Directory of Open Access Journals (Sweden)

    A.A. Vasilyev

    2017-08-01

    Full Text Available Experimental research on behavior of rolled tungsten plates under intense transient heat loads generated by a powerful (a total power of up to 7 MW long-pulse (0.1–0.3ms electron beam with full irradiation area of 2 cm2 was carried out. Imaging of the sample by the fast CCD cameras in the NIR range and with illumination by the 532nm continuous-wave laser was applied for in-situ surface diagnostics during exposure. In these experiments tungsten plates were exposed to heat loads 0.5–1MJ/m2 with a heat flux factor (Fhf close to and above the melting threshold of tungsten at initial room temperature. Crack formation and crack propagation under the surface layer were observed during multiple exposures. Overheated areas with excessive temperature over surrounding surface of about 500K were found on severely damaged samples more than 5ms after beam ending. The application of laser illumination enables to detect areas of intense tungsten melting near crack edges and crack intersections.

  2. Sexual Dimorphism of the Human Tibia through Time: Insights into Shape Variation Using a Surface-Based Approach.

    Directory of Open Access Journals (Sweden)

    Hana Brzobohatá

    Full Text Available In this paper we present a three-dimensional (3D morphometrical assessment of human tibia sexual dimorphism based on whole bone digital representation. To detect shape-size and shape differences between sexes, we used geometric morphometric tools and colour-coded surface deviation maps. The surface-based methodology enabled analysis of sexually dimorphic features throughout the shaft and articular ends of the tibia. The overall study dataset consisted of 183 3D models of adult tibiae from three Czech population subsets, dating to the early medieval (9-10th century (N = 65, early 20th century (N = 61 and 21st-century (N = 57. The time gap between the chronologically most distant and contemporary datasets was more than 1200 years. The results showed that, in all three datasets, sexual dimorphism was pronounced. There were some sex-dimorphic characteristics common to all three samples, such as tuberosity protrusion, anteriorly bowed shaft and relatively larger articular ends in males. Diachronic comparisons also revealed substantial shape variation related to the most dimorphic area. Male/female distinctions showed a consistent temporal trend regarding the location of dimorphic areas (shifting distally with time, while the maximal deviation between male and female digitized surfaces fluctuated and reached the lowest level in the 21st-century sample. Sex determination on a whole-surface basis yielded the lowest return of correct sex assignment in the 20th-century group, which represented the lowest socioeconomic status. The temporal variation could be attributed to changes in living conditions, the decreasing lower limb loading/labour division in the last 12 centuries having the greatest effect. Overall, the results showed that a surface-based approach is successful for analysing complex long bone geometry.

  3. Protein immobilization on epoxy-activated thin polymer films: effect of surface wettability and enzyme loading.

    Science.gov (United States)

    Chen, Bo; Pernodet, Nadine; Rafailovich, Miriam H; Bakhtina, Asya; Gross, Richard A

    2008-12-02

    A series of epoxy-activated polymer films composed of poly(glycidyl methacrylate/butyl methacrylate/hydroxyethyl methacrylate) were prepared. Variation in comonomer composition allowed exploration of relationships between surface wettability and Candida antartica lipase B (CALB) binding to surfaces. By changing solvents and polymer concentrations, suitable conditions were developed for preparation by spin-coating of uniform thin films. Film roughness determined by AFM after incubation in PBS buffer for 2 days was less than 1 nm. The occurrence of single CALB molecules and CALB aggregates at surfaces was determined by AFM imaging and measurements of volume. Absolute numbers of protein monomers and multimers at surfaces were used to determine values of CALB specific activity. Increased film wettability, as the water contact angle of films increased from 420 to 550, resulted in a decreased total number of immobilized CALB molecules. With further increases in the water contact angle of films from 55 degrees to 63 degrees, there was an increased tendency of CALB molecules to form aggregates on surfaces. On all flat surfaces, two height populations, differing by more than 30%, were observed from height distribution curves. They are attributed to changes in protein conformation and/or orientation caused by protein-surface and protein-protein interactions. The fraction of molecules in these populations changed as a function of film water contact angle. The enzyme activity of immobilized films was determined by measuring CALB-catalyzed hydrolysis of p-nitrophenyl butyrate. Total enzyme specific activity decreased by decreasing film hydrophobicity.

  4. Variation in Stiffness of Monopiles in Dense Sand Under Cyclic Lateral Loads

    DEFF Research Database (Denmark)

    Nicolai, Giulio; Ibsen, Lars Bo

    2016-01-01

    The stiffness of the soil-foundation system is an important parameter that is taken into account in design. Recent studies of offshore wind turbines have shown that long-term cyclic lateral loading, induced by waves and wind, may lead to an increase in the foundation stiffness during the lifetime...... of the foundation. This is in contrast to design methods proposed by current guidelines. The present paper represents a further step towards improving the general knowledge regarding such stiffness change issues. Test results from an experimental investigation are presented and discussed. The interpretation focuses...

  5. Surface Tension of Multi-phase Flow with Multiple Junctions Governed by the Variational Principle

    International Nuclear Information System (INIS)

    Matsutani, Shigeki; Nakano, Kota; Shinjo, Katsuhiko

    2011-01-01

    We explore a computational model of an incompressible fluid with a multi-phase field in three-dimensional Euclidean space. By investigating an incompressible fluid with a two-phase field geometrically, we reformulate the expression of the surface tension for the two-phase field found by Lafaurie et al. (J Comput Phys 113:134–147, 1994) as a variational problem related to an infinite dimensional Lie group, the volume-preserving diffeomorphism. The variational principle to the action integral with the surface energy reproduces their Euler equation of the two-phase field with the surface tension. Since the surface energy of multiple interfaces even with singularities is not difficult to be evaluated in general and the variational formulation works for every action integral, the new formulation enables us to extend their expression to that of a multi-phase (N-phase, N ≥ 2) flow and to obtain a novel Euler equation with the surface tension of the multi-phase field. The obtained Euler equation governs the equation for motion of the multi-phase field with different surface tension coefficients without any difficulties for the singularities at multiple junctions. In other words, we unify the theory of multi-phase fields which express low dimensional interface geometry and the theory of the incompressible fluid dynamics on the infinite dimensional geometry as a variational problem. We apply the equation to the contact angle problems at triple junctions. We computed the fluid dynamics for a two-phase field with a wall numerically and show the numerical computational results that for given surface tension coefficients, the contact angles are generated by the surface tension as results of balances of the kinematic energy and the surface energy.

  6. Variations in sea surface roughness induced by the 2004 Sumatra-Andaman tsunami

    Directory of Open Access Journals (Sweden)

    O. A. Godin

    2009-07-01

    Full Text Available Observations of tsunamis away from shore are critically important for improving early warning systems and understanding of tsunami generation and propagation. Tsunamis are difficult to detect and measure in the open ocean because the wave amplitude there is much smaller than it is close to shore. Currently, tsunami observations in deep water rely on measurements of variations in the sea surface height or bottom pressure. Here we demonstrate that there exists a different observable, specifically, ocean surface roughness, which can be used to reveal tsunamis away from shore. The first detailed measurements of the tsunami effect on sea surface height and radar backscattering strength in the open ocean were obtained from satellite altimeters during passage of the 2004 Sumatra-Andaman tsunami. Through statistical analyses of satellite altimeter observations, we show that the Sumatra-Andaman tsunami effected distinct, detectable changes in sea surface roughness. The magnitude and spatial structure of the observed variations in radar backscattering strength are consistent with hydrodynamic models predicting variations in the near-surface wind across the tsunami wave front. Tsunami-induced changes in sea surface roughness can be potentially used for early tsunami detection by orbiting microwave radars and radiometers, which have broad surface coverage across the satellite ground track.

  7. Youth temperament, harsh parenting, and variation in the oxytocin receptor gene forecast allostatic load during emerging adulthood.

    Science.gov (United States)

    Brody, Gene H; Yu, Tianyi; Barton, Allen W; Miller, Gregory E; Chen, Edith

    2017-08-01

    An association has been found between receipt of harsh parenting in childhood and adult health problems. However, this research has been principally retrospective, has treated children as passive recipients of parental behavior, and has overlooked individual differences in youth responsivity to harsh parenting. In a 10-year multiple-wave prospective study of African American families, we addressed these issues by focusing on the influence of polymorphisms in the oxytocin receptor gene (OXTR), variants of which appear to buffer or amplify responses to environmental stress. The participants were 303 youths, with a mean age of 11.2 at the first assessment, and their parents, all of whom were genotyped for variations in the rs53576 (A/G) polymorphism. Teachers rated preadolescent (ages 11 to 13) emotionally intense and distractible temperaments, and adolescents (ages 15 and 16) reported receipt of harsh parenting. Allostatic load was assessed during young adulthood (ages 20 and 21). Difficult preadolescent temperament forecast elevated receipt of harsh parenting in adolescence, and adolescents who experienced harsh parenting evinced high allostatic load during young adulthood. However, these associations emerged only among children and parents who carried A alleles of the OXTR genotype. The results suggest the oxytocin system operates along with temperament and parenting to forecast young adults' allostatic load.

  8. Discrete complexes immobilized onto click-SBA-15 silica: controllable loadings and the impact of surface coverage on catalysis.

    Science.gov (United States)

    Nakazawa, Jun; Smith, Brian J; Stack, T Daniel P

    2012-02-08

    Azidopropyl functionalized mesoporous silica SBA-15 were prepared with variable azide loadings of 0.03-0.7 mmol g(-1) (~2-50% of maximal surface coverage) through a direct synthesis, co-condensation approach. These materials are functionalized selectively with ethynylated organic moieties through a copper-catalyzed azide alkyne cycloaddition (CuAAC) or "click" reaction. Specific loading within a material can be regulated by either the azide loading or limiting the alkyne reagent relative to the azide loading. The immobilization of ferrocene, pyrene, tris(pyridylmethyl)amine (TPA), and iron porphyrin (FeTPP) demonstrates the robust nature and reproducibility of this two-step synthetic attachment strategy. Loading-sensitive pyrene fluorescence correlates with a theoretically random surface distribution, rather than a uniform one; site-isolation of tethered moieties ~15 Å in length occurs at loadings less than 0.02 mmol g(-1). The effect of surface loading on reactivity is observed in the oxygenation of SBA-15-[Cu(I)(TPA)]. SBA-15-[Mn(II)(TPA)]-catalyzed epoxidation exhibits a systematic dependence on surface loading. A comparison of homogeneous, site-isolated and site-dense complexes provides insight into catalyst speciation and ligand activity.

  9. Surface Freshwater Storage Variations in the Orinoco Floodplains Using Multi-Satellite Observations

    Directory of Open Access Journals (Sweden)

    Frédéric Frappart

    2014-12-01

    Full Text Available Variations in surface water extent and storage are poorly characterized from regional to global scales. In this study, a multi-satellite approach is proposed to estimate the water stored in the floodplains of the Orinoco Basin at a monthly time-scale using remotely-sensed observations of surface water from the Global Inundation Extent Multi-Satellite (GIEMS and stages from Envisat radar altimetry. Surface water storage variations over 2003–2007 exhibit large interannual variability and a strong seasonal signal, peaking during summer, and associated with the flood pulse. The volume of surface water storage in the Orinoco Basin was highly correlated with the river discharge at Ciudad Bolivar (R = 0.95, the closest station to the mouth where discharge was estimated, although discharge lagged one month behind storage. The correlation remained high (R = 0.73 after removing seasonal effects. Mean annual variations in surface water volume represented ~170 km3, contributing to ~45% of the Gravity Recovery and Climate Experiment (GRACE-derived total water storage variations and representing ~13% of the total volume of water that flowed out of the Orinoco Basin to the Atlantic Ocean.

  10. A simple UV-ozone surface treatment to enhance photocatalytic performance of TiO 2 loaded polymer nanofiber membranes

    KAUST Repository

    Dilpazir, S.

    2016-01-29

    Homogeneously dispersed titanium dioxide loaded polyacrylonitrile nanofiber membranes with increased active mass loading, Ti3+ surface defects and hydrophilicity were fabricated by combining electrospinning and UV-ozone surface treatment. The photocatalytic activity improved by a factor of ∼2 and the kinetics of photodegradation switched from pseudo-first order to pseudo-second order with increasing TiO2 content with a maximum rate constant of 20.7 h-1. © The Royal Society of Chemistry 2016.

  11. The dependence of surface temperature on IGBTs load and ambient temperature

    Directory of Open Access Journals (Sweden)

    Alexander Čaja

    2015-01-01

    Full Text Available Currently, older power electronics and electrotechnics are improvement and at the same time developing new and more efficient devices. These devices produce in their activities a significant part of the heat which, if not effectively drained, causing damage to these elements. In this case, it is important to develop new and more efficient cooling system. The most widespread of modern methods of cooling is the cooling by heat pipe. This contribution is aimed at cooling the insulated-gate bipolar transistor (IGBT elements by loop heat pipe (LHP. IGBTs are very prone to damage due to high temperatures, and therefore is the important that the surface temperature was below 100°C. It was therefore created a model that examined what impact of surface temperature on the IGBT element and heat removal at different load and constant ambient temperature.

  12. Intelligent detection of cracks in metallic surfaces using a waveguide sensor loaded with metamaterial elements.

    Science.gov (United States)

    Ali, Abdulbaset; Hu, Bing; Ramahi, Omar

    2015-05-15

    This work presents a real life experiment of implementing an artificial intelligence model for detecting sub-millimeter cracks in metallic surfaces on a dataset obtained from a waveguide sensor loaded with metamaterial elements. Crack detection using microwave sensors is typically based on human observation of change in the sensor's signal (pattern) depicted on a high-resolution screen of the test equipment. However, as demonstrated in this work, implementing artificial intelligence to classify cracked from non-cracked surfaces has appreciable impact in terms of sensing sensitivity, cost, and automation. Furthermore, applying artificial intelligence for post-processing data collected from microwave sensors is a cornerstone for handheld test equipment that can outperform rack equipment with large screens and sophisticated plotting features. The proposed method was tested on a metallic plate with different cracks and the obtained experimental results showed good crack classification accuracy rates.

  13. Surface water acidification and critical loads: exploring the F-factor

    Directory of Open Access Journals (Sweden)

    K. Bishop

    2009-11-01

    Full Text Available As acid deposition decreases, uncertainties in methods for calculating critical loads become more important when judgements have to be made about whether or not further emission reductions are needed. An important aspect of one type of model that has been used to calculate surface water critical loads is the empirical F-factor which estimates the degree to which acid deposition is neutralised before it reaches a lake at any particular point in time relative to the pre-industrial, steady-state water chemistry conditions.

    In this paper we will examine how well the empirical F-functions are able to estimate pre-industrial lake chemistry as lake chemistry changes during different phases of acidification and recovery. To accomplish this, we use the dynamic, process-oriented biogeochemical model SAFE to generate a plausible time series of annual runoff chemistry for ca. 140 Swedish catchments between 1800 and 2100. These annual hydrochemistry data are then used to generate empirical F-factors that are compared to the "actual" F-factor seen in the SAFE data for each lake and year in the time series. The dynamics of the F-factor as catchments acidify, and then recover are not widely recognised.

    Our results suggest that the F-factor approach worked best during the acidification phase when soil processes buffer incoming acidity. However, the empirical functions for estimating F from contemporary lake chemistry are not well suited to the recovery phase when the F-factor turns negative due to recovery processes in the soil. This happens when acid deposition has depleted the soil store of BC, and then acid deposition declines, reducing the leaching of base cations to levels below those in the pre-industrial era. An estimate of critical load from water chemistry during recovery and empirical F functions would therefore result in critical loads that are too low. Therefore, the empirical estimates of the F-factor are a significant source of

  14. Within- and among-family variation in parasite load and parasite-induced mortality in the land snail Arianta arbustorum, a host of parasitic mites.

    Science.gov (United States)

    Schüpbach, Hans Ulrich; Baur, Bruno

    2010-08-01

    Variation in host susceptibility and parasite-induced mortality are preconditions for parasite-related selection on host populations. In terrestrial gastropods, variation in resistance against ectoparasite infection is poorly understood. We examined the within- and among-family variation in parasite load in full-siblings of the land snail Arianta arbustorum experimentally infected with Riccardoella limacum , a mite living in the mantle cavity of helicid land snails. We also quantified the influence of family origin and host size on parasite load and calculated its heritability (h(2)). Furthermore, we examined the influence of parasite load, snail size, and family origin on host winter mortality, an important life-history trait of A. arbustorum . Parasite load was heritable (h(2) = 0.63). In infected snails, parasite load was affected by family origin and increased with increasing shell size. Host mortality during hibernation increased with increasing parasite load and differed among families, but was not affected by snail size. Our results show high among-family variation both in resistance against ectoparasite infection and in host winter mortality. Furthermore, we show that parasite load is linked to snail size, which suggests that the proliferation of R. limacum is limited by resources provided by A. arbustorum .

  15. The influence of time-of-day variation and loading on the aponeurosis plantaris pedis

    DEFF Research Database (Denmark)

    Mølgaard, Carsten Møller; Skou, Søren Thorgaard; Rathleff, Michael Skovdal

    2012-01-01

    AIM: The aim of this paper was to investigate the effect of time-of-day on the thickness of the the aponeurosis plantaris pedis, and to examine the acute effects of high-load strength training and long distance running on the thickness of the aponeurosis plantaris pedis. METHODS: Proximal...... not induce changes in the thickness of the aponeurosis plantaris pedis. Time-of-day influences the thickness of the aponeurosis plantaris pedis, but the changes are not larger than measurement uncertainty....... aponeurosis plantaris pedis thickness was assessed with a 13-MHz linear-array transducer. In sub-study 1, ten participants (ten aponeurosis') were measured five times during 24 hours. In sub-study 2, ten participants (ten aponeurosis') were measured just before, immediately after and again three hours after 3...

  16. Variation of surface dose in CT; Variacion de la dosis superficial en Tomografia Computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Aviles Lucas, P.; Castellano, I. A.; Dance, D. R.; Vano Carruana, E.; Prieto Martin, C.

    2003-07-01

    An experimental study has been made of the variations of the air kerma-length product at the surface of a phantom exposed in a CT scanner using clinical parameters. the effect of patient size, position within the gantry plane and beam-shaping filter type was studied using three different elliptical phantoms. A dose reduction technique based on a sinusoidal tube current modulation system was also investigated. the result of the variation of the surface dose was analysed for the case of CT fluoroscopy procedures. The surface air kerma-length product was shown to be independent of phantom size (within experimental error) but decreases as the surface moves vertically away from the iso centre. The major contributor to this variation the beam-shaping filter. The possibility of underestimating the surface dose if an AAPM body phantom is used (a 36% increase for the head phantom) is an indirect result of the previous conclusion when applied to CT fluoroscopy. This highlights the importance of considering the size and position of the patient when measuring the does. Finally, when the tube current modulation system was used, the maximum surface dose reduction was 18%. (Author) 23 refs.

  17. Evaluation of underground pipe-structure interface for surface impact load

    International Nuclear Information System (INIS)

    Wang, Shen

    2017-01-01

    Highlights: • A simple method is proposed for the evaluation of underground pipelines for surface impact load considering the effect of a nearby pipe-structure interface. • The proposed simple method can be used to evaluate the magnitude of damage within a short period of time after accidental drop occurs. • The proposed method is applied in a practical example and compared by using finite element analysis. - Abstract: Nuclear safety related buried pipelines need to be assessed for the effects of postulated surface impact loads. In published solutions, the buried pipe is often considered within an elastic half space without interference with other underground structures. In the case that a surface impact occurs in short distance from an underground pipe-structure interface, this boundary condition will further complicate the buried pipe evaluation. Neglecting such boundary effect in the assessment may lead to underestimating potential damage of buried pipeline, and jeopardizing safety of the nuclear power plant. Comprehensive analysis of such structure-pipe-soil system is often subjected to availability of state-of-art finite element tools, as well as costly and time consuming. Simple, but practical conservative techniques have not been established. In this study, a mechanics based solution is proposed in order to assess the magnitude of damage to a buried pipeline beneath a heavy surface impact considering the effect of a nearby pipe-structure interface. The proposed approach provides an easy to use tool in the early stage of evaluation before the decision of applying more costly technique can be made by owner of the nuclear facility.

  18. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Science.gov (United States)

    Landman, I. S.; Pestchanyi, S. E.; Safronov, V. M.; Bazylev, B. N.; Garkusha, I. E.

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 102 MJ/m 2 on a time scale Ïä of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q âe 1/4 3 MJ/m2 and Ïä âe 1/4 0.3 ms, deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q = 10–30 MJ/m2 and Ïä = 0.03–0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  19. Nuclear reactor control method for maintaining an appreciably constant axial distribution of power with load variations

    International Nuclear Information System (INIS)

    Morita, Toshio.

    1975-01-01

    A nuclear reactor control method is described in which the power variations of the reactor are controlled partly by varying the concentration of the neutron absorbing element and partly by varying the positions of the control rods, in order to maintain the axial distribution of power appreciably symmetrical during the normal operation of the reactor. The control points are located in the upper and lower halves of the core. The controls are operated to maintain the output power difference between the upper and lower halves of the core, based on the total output power (axial deviation) significantly equal to a predetermined optimum figure during the entire running of the reactor, including when there are power variations. The optimum value is obtained by determining the axial deviation at full power with the xenon in balance and all the control rods withdrawn from the fuel area of the core. This optimum value is recalculated after a period appreciably equal to that of a month's operation at full power. This method applies in particular to PWR type reactors [fr

  20. Modelling reduction of urban heat load in Vienna by modifying surface properties of roofs

    Science.gov (United States)

    Žuvela-Aloise, Maja; Andre, Konrad; Schwaiger, Hannes; Bird, David Neil; Gallaun, Heinz

    2018-02-01

    The study examines the potential of urban roofs to reduce the urban heat island (UHI) effect by changing their reflectivity and implementing vegetation (green roofs) using the example of the City of Vienna. The urban modelling simulations are performed based on high-resolution orography and land use data, climatological observations, surface albedo values from satellite imagery and registry of the green roof potential in Vienna. The modelling results show that a moderate increase in reflectivity of roofs (up to 0.45) reduces the mean summer temperatures in the densely built-up environment by approximately 0.25 °C. Applying high reflectivity materials (roof albedo up to 0.7) leads to average cooling in densely built-up area of approximately 0.5 °C. The green roofs yield a heat load reduction in similar order of magnitude as the high reflectivity materials. However, only 45 % of roof area in Vienna is suitable for greening and the green roof potential mostly applies to industrial areas in city outskirts and is therefore not sufficient for substantial reduction of the UHI effect, particularly in the city centre which has the highest heat load. The strongest cooling effect can be achieved by combining the green roofs with high reflectivity materials. In this case, using 50 or 100 % of the green roof potential and applying high reflectivity materials on the remaining surfaces have a similar cooling effect.

  1. Centennial scale variations of sea-surface conditions in Disko Bugt, west Greenland

    Science.gov (United States)

    Allan, E.; de Vernal, A.; Knudsen, M. F.; Moros, M.; Ribeiro, S.; Ouellet-Bernier, M. M.

    2017-12-01

    Palynological analyses of the sediment core MSM343310 from Disko Bugt (68°38'861 N, 53°49'493 W) documents decadal-centennial variations in surface waters during the last 3600 years. The dinocyst assemblages dominated by Islandinium minutum, Brigantedinium spp., Islandinium? cezare and the cyst of Pentapharsodinium dalei, indicate large seasonal gradients of temperature due to stratified surface waters and high dinocyst fluxes (>104 cysts/cm2year1) point to an extremely high productivity. The application of the modern analogue technique to dinocyst assemblages indicates centennial scale variation of sea-surface salinity and temperature, in phase with δ18O fluctuation in the Camp Century ice core. Moreover, the seasonal sea ice cover records an important regime change at about 1.5 ka BP, from winter only sea-ice cover to more unstable conditions with successive cooling pulses reaching up to 8 months/year of ice coverage. The reconstructions of sea-surface conditions from Disko Bugt suggest relationship between hydrographic conditions and regional climate over Greenland. In particular, our record, which shows variations with a mean 200-year period until about 2 ka BP, supports the hypothesis of climate variations driven by the solar variability. Our data that show another 60- to 70-year period after 1.5 ka BP also suggest linkages with the Atlantic Multidecadal Oscillation and lead to propose that the cooling recorded after 1.5 ka BP corresponds to a southeastward migration of the summer polar front.

  2. Spatial and temporal variation of surface waves in shallow waters along the eastern Arabian Sea.

    Digital Repository Service at National Institute of Oceanography (India)

    Anoop, T.R.; SanilKumar, V.; Shanas, P.R.

    We studied the spatial and temporal variation of surface waves along the eastern Arabian Sea during 2011 and 2012. Measured directional wave data at two shallow water locations and re-analysis datasets (ERA-Interim) at 0.751 intervals at four...

  3. Variations of surface temparature with solar activity at two stations in ...

    African Journals Online (AJOL)

    Nigeria Journal of Pure and Applied Physics ... A consistent and persistent diurnal variation in surface air temperature exists which shows an almost constant level in the early morning hours (0000 0600 hours LT.); a rise at sunrise till about 1500 hr LT., a subsequent fall to the constant level by about 1900 hr LT. at sunset.

  4. Spatial Variation of Phosphorous Retention Capacity in Subsurface Flow Constructed Wetlands: Effect of Wetland Type and Inflow Loading.

    Directory of Open Access Journals (Sweden)

    Guangwei Yu

    Full Text Available For verification of spatial distribution of phosphorous retention capacity in constructed wetlands systems(CWs, two horizontal subsurface flow(HSSF CWs and two vertical subsurface flow(VSSF CWs, using sand as substrate and Typha latifolia as wetland plants, were constructed and put into use for synthetic wastewater treatment. Five months later, significant spatial variations of TP and inorganic phosphorus(Ca-P, Fe-P and Al-P were observed, which were found to be greatly affected by CWs type and hydraulic loading. The results revealed that though spatial distribution of Fe-P and Al-P displayed a similar order of substrate content as "rhizosphere" > "near-rhizosphere" > "non-rhizosphere" and "inflow section" > "outflow section" regardless of types and loading, the distribution of Ca-P was positively correlated to that of Fe-P and Al-P in HSSF CWs, while negative correlation was shown in VSSF CWs. As a result, TP spatial distribution in HSSF CWs demonstrated a greater dissimilarity than that in VSSF CWs. For HSSF CWs with low hydraulic loading, the lowest TP content was found in non-rhizosphere substrate of outflow section, while the highest one was discovered in rhizonsphere substrate of inflow section. The values in 6 parts of areas ranged from 0.138 g·kg-1 to 2.710 g·kg-1, which also were from -33.5% to 1209% compared to the control value. On contrast, spatial difference of TP content in substrates of VSSF CWs was insignificant, with a variation ranging from 0.776 g·kg-1 to 1.080 g·kg-1, that was 275% to 421% higher than the control value. In addition, when hydraulic loading was increased, TP content in VSSF CWs sharply decreased, ranging from 0.210 g·kg-1 to 0.634 g·kg-1. Meanwhile, dissimilarity of TP spatial distribution in HSSF CWs was reduced, with TP content ranging from 0.258 g·kg-1 to 2.237 g·kg-1. The results suggested that P spatial distribution should be taken into account for CWs design and operation.

  5. Parametric study of dielectric loaded surface plasmon polariton add-drop filters for hybrid silicon/plasmonic optical circuitry

    Science.gov (United States)

    Dereux, A.; Hassan, K.; Weeber, J.-C.; Djellali, N.; Bozhevolnyi, S. I.; Tsilipakos, O.; Pitilakis, A.; Kriezis, E.; Papaioannou, S.; Vyrsokinos, K.; Pleros, N.; Tekin, T.; Baus, M.; Kalavrouziotis, D.; Giannoulis, G.; Avramopoulos, H.

    2011-01-01

    Surface plasmons polaritons are electromagnetic waves propagating along the surface of a conductor. Surface plasmons photonics is a promising candidate to satisfy the constraints of miniaturization of optical interconnects. This contribution reviews an experimental parametric study of dielectric loaded surface plasmon waveguides ring resonators and add-drop filters within the perspective of the recently suggested hybrid technology merging plasmonic and silicon photonics on a single board (European FP7 project PLATON "Merging Plasmonic and Silicon Photonics Technology towards Tb/s routing in optical interconnects"). Conclusions relevant for dielectric loaded surface plasmon switches to be integrated in silicon photonic circuitry will be drawn. They rely on the opportunity offered by plasmonic circuitry to carry optical signals and electric currents through the same thin metal circuitry. The heating of the dielectric loading by the electric current enables to design low foot-print thermo-optical switches driving the optical signal flow.

  6. Nonlocal, refined plate, and surface effects theories used to analyze free vibration of magnetoelectroelastic nanoplates under thermo-mechanical and shear loadings

    Science.gov (United States)

    Karimi, Morteza; Shahidi, Ali Reza

    2017-05-01

    The theories of nonlocal, refined plate, and surface effects are used in this study to investigate the free vibration of magnetoelectroelastic (MEE) nanoplates resting on elastic foundations. For this purpose, the MEE nanoplate is subjected not only to external magnetic and electric potentials but also to thermal and shear in-plane loads. The refined plate theory is used and the Maxwell equations and magnetoelectric boundary conditions employed to determine the variations in the electric and magnetic potentials along the direction of the nanoplate thickness. This is followed by deriving the governing equations based on the Hamilton's principle, which are then solved via the generalized differential quadrature method. In a later stage of the study, the effects of electric and magnetic potentials, nonlocal parameter, thermal and shear in-plane loading, Winkler and shear moduli, different boundary conditions, and aspect ratio are explored in a parametric study on the surface effects of vibration characteristics of MEE nanoplates. It is found that the effect of surface parameters enhanced with increases in nonlocal parameter, electric potential, in-plane shear load, and temperature change. However, this effect is observed to decrease when the magnetic potential, dimensionless Winkler and shear moduli, and nanoplate thickness are augmented.

  7. Seasonal variation and speciation of dissolved iron in an artificial surface water body

    Directory of Open Access Journals (Sweden)

    Birghila Semaghiul

    2017-12-01

    Full Text Available The aquatic chemistry of iron is an important issue since iron is a micronutrient for the growth of phytoplankton. Its concentration in surface waters involves many environmental aspects, from the quality of a particular water to the control of atmospheric carbon dioxide. Dissolved iron can exist in water as ferrous and ferric iron, and the equilibrium between these two forms, as well as the precipitation and solubilization of iron, depends on many natural and anthropic factors. We studied the variation for an year of Fe(II and total iron concentration into Poarta Alba - Midia Navodari Canal, an artificial surface water which connects Danube River with Black Sea. The results indicate a high iron concentration in surface water and a seasonal variation of iron concentration and speciation, which can be correlated with the oxidable matter content.

  8. The mechanics of American football cleats on natural grass and infill-type artificial playing surfaces with loads relevant to elite athletes.

    Science.gov (United States)

    Kent, Richard; Forman, Jason L; Lessley, David; Crandall, Jeff

    2015-06-01

    This study quantified the mechanical interactions of 19 American football cleats with a natural grass and an infill-type artificial surface under loading conditions designed to represent play-relevant manoeuvres of elite athletes. Variation in peak forces and torques was observed across cleats when tested on natural grass (2.8-4.2 kN in translation, 120-174 Nm in rotation). A significant (p force and torque on natural grass. Almost all of the cleats caused shear failure of the natural surface, which generated a divot following a test. This is a force-limiting cleat release mode. In contrast, all but one of the cleat types held fast in the artificial turf, resulting in force and torque limited by the prescribed input load from the test device (nom. 4.8 kN and 200 Nm). Only one cleat pattern, consisting of small deformable nubs, released on the artificial surface and generated force (3.9 kN) comparable to the range observed with natural grass. These findings (1) should inform the design of cleats intended for use on natural and artificial surfaces and (2) suggest a mechanical explanation for a higher lower-limb injury rate in elite athletes playing on artificial surfaces.

  9. Decentralized Electric Vehicle Charging Strategies for Reduced Load Variation and Guaranteed Charge Completion in Regional Distribution Grids

    Directory of Open Access Journals (Sweden)

    Weige Zhang

    2017-01-01

    Full Text Available A novel, fully decentralized strategy to coordinate charge operation of electric vehicles is proposed in this paper. Based on stochastic switching control of on-board chargers, this strategy ensures high-efficiency charging, reduces load variations to the grid during charging periods, achieves charge completion with high probability, and accomplishes approximate “valley-filling”. Further improvements on the core strategy, including individualized power management, adaptive strategies, and battery support systems, are introduced to further reduce power fluctuation variances and to guarantee charge completion. Stochastic analysis is performed to establish the main properties of the strategies and to quantitatively show the performance improvements. Compared with the existing decentralized charging strategies, the strategies proposed in this paper can be implemented without any information exchange between grid operators and electric vehicles (EVs, resulting in a communications cost reduction. Additionally, it is shown that by using stochastic charging rules, a grid-supporting battery system with a very small energy capacity can achieve substantial reduction of EV load fluctuations with high confidence. An extensive set of simulations and case studies with real-world data are used to demonstrate the benefits of the proposed strategies.

  10. Fluctuation of microbial activities after influent load variations in a full-scale SBR. Recovery of the biomass after starvation

    Energy Technology Data Exchange (ETDEWEB)

    Cabezas, Angela; Draper, Patricia; Etchebehere, Claudia [Universidad de la Republica, Montevideo (Uruguay). Catedra de Microbiologia, Facultad de Quimica y Facultad de Ciencias

    2009-10-15

    Due to variations in the production levels, a full-scale sequencing batch reactor (SBR) for post-treatment of tannery wastewater was exposed to low and high ammonia load periods. In order to study how these changes affected the N-removal capacity, the microbiology of the reactor was studied by a diverse set of techniques including molecular tools, activity tests, and microbial counts in samples taken along 3 years. The recover capacity of the biomass was also studied in a lab-scale reactor operated with intermittent aeration without feeding for 36 days. The results showed that changes in the feeding negatively affected the nitrifying community, but the nitrogen removal efficiencies could be restored after the concentration stress. Species substitution was observed within the nitrifying bacteria, Nitrosomonas europaea and Nitrobacter predominated initially, and after an ammonia overload period, Nitrosomonas nitrosa and Nitrospira became dominant. Some denitrifiers, with nirS related to Alicycliphilus, Azospirillum, and Marinobacter nirS, persisted during long-term reactor operation, but the community fluctuated both in composition and in abundance. This fluctuating community may better resist the continuous changes in the feeding regime. Our results showed that a nitrifying-denitrifying SBR could be operated with low loads or even without feeding during production shut down periods. (orig.)

  11. Surface modification of the MoSiON phase shift mask to reduce critical dimension variation

    Science.gov (United States)

    Choo, Hyeokseong; Seo, Dongwan; Lim, Sangwoo

    2013-10-01

    Phase shift masks (PSMs) were introduced to extend the limits of optical lithography. However, cleaning a MoSiON-based PSM pattern with an ammonium hydroxide/hydrogen peroxide mixture (APM), although efficient at cleaning the PSM pattern, etches the PSM layer, inducing changes in the phase angle and transmittance due to the introduction of variation of the critical dimension (CD). In this study, we investigated the effects of plasma treatment and furnace annealing on the etching of the MoSiON PSM in APM. In particular, we found that the etch behavior and surface chemical state after each treatment were correlated. We also compared variations in the CD between patterned PSM layers and blank masks. After O2 or N2 plasma treatment, the top surface of MoSiON had a thicker transition layer with an extreme increase in O, and a huge variation in CD was also observed after APM treatment. However, CD variation of the patterned MoSiON layer was minimal when the sample was first annealed in NH3 ambient gas and then subjected to APM treatment. This phenomenon may be related to an increase in the portion of the SiO2-like state at the top surface of the MoSiON PSM layer and its optimization without a change in the transition layer thickness.

  12. Seasonal Greenland Ice Sheet ice flow variations in regions of differing bed and surface topography

    Science.gov (United States)

    Sole, A. J.; Livingstone, S. J.; Rippin, D. M.; Hill, J.; McMillan, M.; Quincey, D. J.

    2015-12-01

    The contribution of the Greenland Ice Sheet (GrIS) to future sea-level rise is uncertain. Observations reveal the important role of basal water in controlling ice-flow to the ice sheet margin. In Greenland, drainage of large volumes of surface meltwater to the ice sheet bed through moulins and hydrofracture beneath surface lakes dominates the subglacial hydrological system and provides an efficient means of moving mass and heat through the ice sheet. Ice surface and bed topography influence where meltwater can access the bed, and the nature of its subsequent flow beneath the ice. However, no systematic investigation into the influence of topographic variability on Greenland hydrology and dynamics exists. Thus, physical processes controlling storage and drainage of surface and basal meltwater, and the way these affect ice flow are not comprehensively understood. This presents a critical obstacle in efforts to predict the future evolution of the GrIS. Here we present high-resolution satellite mapping of the ice-surface drainage network (e.g. lakes, channels and moulins) and measurements of seasonal variations in ice flow in south west Greenland. The region is comprised of three distinct subglacial terrains which vary in terms of the amplitude and wavelength and thus the degree to which basal topography is reflected in the ice sheet surface. We find that the distribution of surface hydrological features is related to the transfer of bed topography to the ice sheet surface. For example, in areas of thinner ice and high bed relief, moulins occur more frequently and are more uniformly dispersed, indicating a more distributed influx of surface-derived meltwater to the ice sheet bed. We investigate the implications of such spatial variations in surface hydrology on seasonal ice flow rates.

  13. Load-bearing evaluation of spinal posterior column by measuring surface strain from lumbar pedicles. An in vitro study.

    Science.gov (United States)

    Sun, Peidong; Zhao, Weidong; Bi, Zhenyu; Wu, Changfu; Ouyang, Jun

    2012-01-01

    An understanding of the load transfer within spinal posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant such as artificial intervertebral disc and the dynamic spine stabilization systems. In this study, a new method has been developed for evaluating the load bearing of spinal posterior column by the surface strain of spinal pedicle response to the loading of spinal segment. Six cadaveric lumbar spine segments were biomechanically evaluated between levels L1 and L5 in intact condition and the strain gauges were pasted to an inferior surface of L2 pedicles. Multidirectional flexibility testing used the Panjabi testing protocol; pure moments for the intact condition with overall spinal motion and unconstrained intact moments of ±8 Nm were used for flexion-extension and lateral bending testing. High correlation coefficient (0.967-0.998) indicated a good agreement between the load of spinal segment and the surface strain of pedicle in all loading directions. Principal compressive strain could be observed in flexion direction and tensile strain in extension direction, respectively. In conclusion, the new method seems to be effective for evaluating posterior spinal column loads using pedicles' surface strain data collected during biomechanical testing of spine segments.

  14. Is the current stress state in the Central Amazonia caused by surface water loading?

    Science.gov (United States)

    Ibanez, Delano M.; Riccomini, Claudio; Miranda, Fernando P.

    2014-11-01

    We present new fault data for the region of the Manaus, Central Amazonia, Brazil. Field measurements concentrate on the Miocene-Holocene sedimentary deposits exposed on the Amazonas River Basin, in order to investigate the development of this region in this time-interval. Two faulting events are distinguished since the Miocene. The oldest one is related to NW-SE extension during Miocene times and associated with paleoseismicity, while the younger is associated with NE-SW extension direction and seems to persist today. These two deformational events may be thereby considered Neotectonic. Moreover, the second extensional pulse with NE-SW orientation can be explained by the surface hydrological loading, which induces the Central Amazonia flexural subsidence and may promote extensional stresses in the upper crust.

  15. Metal-loaded graphene surface plasmon waveguides working in the terahertz regime

    DEFF Research Database (Denmark)

    Xiao, Binggang; Qin, Kang; Xiao, Sanshui

    2015-01-01

    A metal-loaded graphene surface plasmon waveguide composed of a thin silica layer sandwiched between a graphene layer and a metal stripe is proposed and the waveguiding properties in the THz regime are numerically investigated. The results show that the fundamental mode of the proposed waveguide...... is tightly confined in the middle silica layer with an acceptable propagation loss. Compared with most other graphene waveguides proposed in the literature, the realization of this waveguide does not need to pattern or deform the graphene layer, thus retaining the superior properties of bulk graphene...... material. The tight modal confinement and the ease of fabrication suggest the high potential use of this waveguide in high-density THz photonic integration....

  16. [Preparation of red mud loaded Co catalysts: optimization using response surface methodology (RSM) and activity evaluation].

    Science.gov (United States)

    Li, Hua-Nan; Xu, Bing-Bing; Qi, Fei; Sun, De-Zhi

    2013-11-01

    The removal efficiency of catalytic ozonation of bezafibrate (BZF) by red mud loaded Co catalysts (Co/RM) was used as the index value in statistical experimental designs. The most important factors influencing BZF degradation (P removal efficiency was 71.29% as calculated by predictive value and a maximum removal efficiency of 70.74% was actually achieved. The experiment data was very close to the predictive value and the deviation was 1% (component formed on the surface of RM by the addition of cobalt into red mud, enhanced the catalytic activity. Moreover, the dissolved metal concentration in the solution for catalytic ozonation of BZF degradation by RM or Co/RM was determined by ICP-OES. The results showed that for both catalysts there was no leaching of catalytic active components into the solution, which could suggest that the two catalysts were safe and could have certain application prospect.

  17. Variation of moment-curvature diagrams in square columns of reinforced concrete due to the presence of loads outside the plane

    International Nuclear Information System (INIS)

    Calvo Camacho, Glen

    2014-01-01

    An experimental investigation was developed to determine if has existed a variation in the moment-curvature diagrams, basic input of performance-based methodologies, due to the presence of loads outside the plane. A documentary revision of experimental, analytical and instrumentation methods is contemplated for the determination of the effect of loads outside the plane, the design of a prototype column in agreement with the requirements of current design, the construction and the failure of four columns subjected to different requests of load outside the plane. The test has consisted of a column of 14 cm of cantilevered side to which horizontal load combinations are applied, outside and inside the plane, in the upper part, as well as an axial load by means of a system of post tension with servo control. Four specimens are studied in which the only difference has been the horizontal load applied. An incremental load is applied for the control case in the plane until reaching the structural failure. The remaining tests are developed based on the magnitude of the maximum load, for which a constant load is first applied outside the plane corresponding to a percentage of the control load (30%, 50% and 80%) and then has proceed to apply the incremental load in the plane. The results have showed that for out-of-plane loads greater than 30%, both ultimate curvature and capacity are considerably reduced. In addition, a linear reduction of the ductility of the element is observed as the loads outside the plane increase. An underestimation of capabilities is shown in analytical research. In addition, the software used is shown without consider the effect of off-plane loads. (author) [es

  18. Interannual Variation of Surface Circulation in the Japan/East Sea due to External Forcings and Intrinsic Variability

    Science.gov (United States)

    Choi, Byoung-Ju; Cho, Seong Hun; Jung, Hee Seok; Lee, Sang-Ho; Byun, Do-Seong; Kwon, Kyungman

    2018-03-01

    The interannual variation of surface ocean currents can be as large as seasonal variation in the Japan/East Sea (JES). To identify the major factors that cause such interannual variability of surface ocean circulation in the JES, surface circulation was simulated from 1998 to 2009 using a three-dimensional model. Contributions of atmospheric forcing (ATM), open boundary data (OBC), and intrinsic variability (ITV) of the surface flow in the JES on the interannual variability of surface ocean circulation were separately examined using numerical simulations. Variability in surface circulation was quantified in terms of variance in sea surface height, 100-m depth water temperature, and surface currents. ITV was found to be the dominant factor that induced interannual variabilities of surface circulation, the main path of the East Korea Warm Current (EKWC), and surface kinetic energy on a time scale of 2-4 years. OBC and ATM were secondary factors contributing to the interannual variation of surface circulation. Interannual variation of ATM changed the separation latitude of EKWC and increased the variability of surface circulation in the Ulleung Basin. Interannual variation of OBC enhanced low-frequency changes in surface circulation and eddies in the Yamato Basin. It also modulated basin-wide uniform oscillations of sea level. This study suggests that precise estimation of initial conditions using data assimilation is essential for long-term prediction of surface circulation in the JES.

  19. GENERATION OF A VECTOR OF NODAL FORCES PRODUCED BY LOADS PRE-SET BY THE ARBITRARY SCULPTED SURFACE DESIGNATED FOR UNIVERSAL STRESS ANALYSIS SOFTWARE

    Directory of Open Access Journals (Sweden)

    Shaposhnikov Nikolay Nikolaevich

    2012-10-01

    A user may select the surface accommodating any simulated arbitrary load; further, a point of the pre-set load intensity specified in the Distributed Load Q field of interface window Distributed Loads, and the point of zero intensity load are to be specified. The above source data are used to calculate the scale coefficient of transition from linear distances to the real value of the load intensity generated within the coordinate surface. The point of zero load intensity represents a virtual plane of zero distributed load values. The proposed software designated for the conversion of arbitrary distributed loads into the nodal load is compact; therefore, it may be integrated into modules capable of exporting the nodal load into other systems of strength analysis, though functioning as a problem-oriented geometrical utility of AutoCAD.

  20. Creep of MDF panels under constant load and cyclic environmental conditions. Influence of surface coating

    Directory of Open Access Journals (Sweden)

    Fernández-Golfín, J. I.

    1997-06-01

    Full Text Available Four different strategies of surface coating (based on 80 g m2 melamin impregnated papers were used on 19 mm thick commercial MDF panels to assess its reological behaviour under cyclic humidity conditions (20ºC 30 % rh-20ºC 90 % rh. Three different levels of stress (20 %, 30 % and 40 %, based on the ultimate load in bending, were used. Tests were conducted by means of the three points load system. For the same stress level, the relative creep of MDF panels was higher than that in particle boards with similar characteristics. This behaviour was just the opposite than the one exhibited by the panels when the comparison is made based on the same level of load (kg Melamin coating seems to strongly influence the creep behaviour of the raw material, especially when surface and edge coating were combined.

    Cuatro tipos de acabados superficiales distintos, aplicados sobre tableros MDF comerciales de 19 mm de espesor, son empleados en el estudio del comportamiento reológico de los tableros MDF ante condiciones alternantes de humedad relativa (20ºC/30 % hr-20ºC/90 % hr. Para el análisis del comportamiento reológico de los tableros se consideran tres niveles de tensión distintos (20 %, 30 %y 40 %, calculados en función de la carga última de rotura a flexión. Los ensayos son efectuados aplicando la carga en punto medio. La fluencia relativa de los tableros MDF resulta ser superior a la exhibida por los tableros de partículas de similares características, observándose que los revestimientos melamínicos aplicados superficialmente influyen eficazmente en la mejora de su comportamiento reológico. Cuando la comparación entre tableros MDF y de partículas se efectúa considerando idénticos niveles de carga aplicada en vez de tensión, el resultado de la comparación resulta ser, justamente, el contrario.

  1. The Contribution of Reservoirs to Global Land Surface Water Storage Variations

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Tian; Nijssen, Bart; Gao, Huilin; Lettenmaier, Dennis P.

    2016-12-21

    Man-made reservoirs play a key role in the terrestrial water system. They alter water fluxes at the land surface and impact surface water storage through water management regulations for diverse purposes such as irrigation, municipal water supply, hydropower generation, and flood control. Although most developed countries have established sophisticated observing systems for many variables in the land surface water cycle, long-term and consistent records of reservoir storage are much more limited and not always shared. Furthermore, most land surface hydrological models do not represent the effects of water management activities. Here, the contribution of reservoirs to seasonal water storage variations is investigated using a large-scale water management model to simulate the effects of reservoir management at basin and continental scales. The model was run from 1948 to 2010 at a spatial resolution of 0.258 latitude–longitude. A total of 166 of the largest reservoirs in the world with a total capacity of about 3900 km3 (nearly 60%of the globally integrated reservoir capacity) were simulated. The global reservoir storage time series reflects the massive expansion of global reservoir capacity; over 30 000 reservoirs have been constructed during the past half century, with a mean absolute interannual storage variation of 89 km3. The results indicate that the average reservoir-induced seasonal storage variation is nearly 700 km3 or about 10%of the global reservoir storage. For some river basins, such as the Yellow River, seasonal reservoir storage variations can be as large as 72%of combined snow water equivalent and soil moisture storage.

  2. Sea-surface salinity variations in the northern Caribbean Sea across the Mid-Pleistocene Transition

    OpenAIRE

    Sepulcre, S.; Vidal, L.; Tachikawa, K.; Rostek, F.; Bard, E.

    2011-01-01

    By reconstructing past hydrologic variations in the Northern Caribbean Sea and their influence on the stability of the Atlantic Meridional Overturning Circulation (AMOC) during the last 940 ka, we seek to document climate changes in this tropical area in response to the Mid-Pleistocene Transition (MPT). Using core MD03-2628, we estimated past changes in sea surface salinity (SSS) using Δδ18O, the difference between the modern, and the past &delta...

  3. Phenological Variations in the Surface Flavonoids of Artemisia vulgaris L. and Artemisia absinthium L.

    OpenAIRE

    NIKOLOVA, Milena; VELICKOVIC, Dragan

    2007-01-01

    Qualitative and quantitative variations in the surface flavonoids in relation to phenological development of Artemisia vulgaris L. and Artemisia absinthium L. were examined. Plant material was harvested at different phenological stages (vegetative, before budding, floral budding, flowering, and fruiting) of the life cycle of the species. In A. vulgaris and A. absinthium acetone exudates, 6 and 4 flavonoid aglycones were identified, respectively, by TLC analysis. Quercetin 3,7,3'-trim...

  4. Effect of Surface Modifications on the Retention of Cement-retained Implant Crowns under Fatigue Loads: An In vitro Study

    Science.gov (United States)

    Ajay, R.; Suma, K.; Ali, Seyed Asharaf; Kumar Sivakumar, Jambai Sampath; Rakshagan, V.; Devaki, V.; Divya, K.

    2017-01-01

    Background: Masticatory forces cause fatigue to the dental luting agents, adversely affecting the retention of these cement-retained crowns. Sandblasting (SB) and diamond abrading the abutment surface improves the bond strength of luting agents. However, the effect of acid etching (AE) on the implant abutment surface and the effect of other surface modifications under masticatory load are yet to be documented. Purpose: The aim of the study was to evaluate the effect of abutment surface modifications on the retention of cement-retained restorations subjected to cyclic fatigue loads. Materials and Methods: Forty Ni-Cr copings were made on Cp-titanium laboratory analogs. The specimens were divided into two groups as Group I: Uniaxial tensile loading (UTL) and Group II: Offaxial cyclic loading followed by uniaxial tensile loading [CTL]. Further subgrouped as, subgroup I: Control (C), subgroup II: SB, subgroup III: AE, and subgroup IV: SB + AE. The copings were luted with Zn2(PO4)3 and subjected to uniaxial tensile loading. Copings were recemented, and CTL was conducted. Two-way analysis of variance was used as the statistical test of significance. Results: In relation to the subgroups, the bond strength of Zn2(PO4)3 was higher in Group I than in Group II. The bond strength in subgroup IV was superior in both Group I and Group II (547.170 N ± 5.752 and 531.975 N ± 6.221 respectively). Conclusions: For both UTL and CTL, abutment SB + AE elicited maximum coping retention followed by AE. Off-axial cyclic loading adversely affected the retention irrespective of the surface modifications. PMID:29284956

  5. Impurities and Electronic Property Variations of Natural MoS 2 Crystal Surfaces

    KAUST Repository

    Addou, Rafik

    2015-09-22

    Room temperature X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), high resolution Rutherford backscattering spectrometry (HR-RBS), Kelvin probe method, and scanning tunneling microscopy (STM) are employed to study the properties of a freshly exfoliated surface of geological MoS2 crystals. Our findings reveal that the semiconductor 2H-MoS2 exhibits both n- and p-type behavior, and the work function as measured by the Kelvin probe is found to vary from 4.4 to 5.3 eV. The presence of impurities in parts-per-million (ppm) and a surface defect density of up to 8% of the total area could explain the variation of the Fermi level position. High resolution RBS data also show a large variation in the MoSx composition (1.8 < x < 2.05) at the surface. Thus, the variation in the conductivity, the work function, and stoichiometry across small areas of MoS2 will have to be controlled during crystal growth in order to provide high quality uniform materials for future device fabrication. © 2015 American Chemical Society.

  6. Assessment of agar gel loaded with micro-emulsion for the cleaning of porous surfaces

    Directory of Open Access Journals (Sweden)

    Florence Gorel

    2010-11-01

    Full Text Available Le système composé d’un gel d’agar-agar et d’une microémulsion présente plusieurs qualités pour extraire des matériaux hydrophobes de couches poreuses. Les propriétés rhéologiques de ce système sont adaptées à un usage en restauration et sont stables pendant plusieurs jours. Les gels permettent la solubilisation du matériau à l’aide de faible quantité de solvant, l’empêchent de créer des auréoles, permettent le contrôle de l’évaporation des solvants et ne laissent pas de résidus de gel dans les pores.Agar gel loaded with micro-emulsion could be used to extract lipophilic materials from porous surfaces. The physical properties of the gels are good enough for a conservation work. They allow the micro-emulsion to flow on the porous surface and to wet it but maintain the micro-emulsion in its structure and prevent the formation of rings. The evaporation of the solvents is slowed down and the gels can be used during a long period.

  7. Assessment of broiler surface temperature variation when exposed to different air temperatures

    Directory of Open Access Journals (Sweden)

    GR Nascimento

    2011-12-01

    Full Text Available This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST of 7- to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb® broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 ºC to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05 from the values obtained by the equations. MST values significantly increased (p < 0.05 when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

  8. Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

    Science.gov (United States)

    Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

    2011-01-01

    Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

  9. Automated detection of cracks on the faying surface within high-load transfer bolted speciments

    Science.gov (United States)

    Wheatley, Gregory; Kollgaard, Jeffrey R.

    2003-07-01

    Boeing is currently conducting evaluation testing of the Comparative Vacuum Monitoring (CVMTM) system offered by Structural Monitoring Systems, Ltd (SMS). Initial testing has been conducted by SMS, with further test lab validations to be performed at Boeing in Seattle. Testing has been conducted on dog bone type specimens that have been cut at the center line. A notch was cut at one of the bolt holes and a CVM sensor installed on both sides of the plate. The doublers were added and a single line of 4 bolts along the longitudinal center line were used to attach the doubler plates to the dog bone type specimen. In this way, a high load transfer situation exists between the two halves of the dog bone specimen and the doubler plates. The CVM sensors are slightly over 0.004" (0.1mm) in thickness and are installed directly upon the faying surface of the dog bone specimen. Testing was conducted on an Instron 8501 Servohydraulic testing machine at the Department of Mechanical and Materials Engineering, University of Western Australia. The standard laboratory equipment offered by Structural Monitoring Systems, Ltd was used for crack detection. This equipment included the Kvac (vacuum supply) and the Sim8 (flow meter). The Sim8 was electrically connected to the Instron machine so that as soon as a crack was detected, fatigue loading was halted. The aim of the experiment was for CVM to detect a crack on the faying surface of the specimens at a length of 0.050" +/- 0.010". This was accomplished successfully. CVM has been developed on the principle that a small volume maintained at a low vacuum is extremely sensitive to any ingress of air. In addition to the load bearing sensors described above, self-adhesive, elastomeric sensors with fine channels on the adhesive face have been developed. When the sensors have been adhered to the structure under test, these fine channels, and the structure itself, form a manifold of galleries alternately at low vacuum and atmospheric pressure

  10. On the use of lifting surface theory for moderately and heavily loaded ship propellers

    NARCIS (Netherlands)

    Van Gent, W.

    1977-01-01

    It is usual to subdivide the loading range of a ship propeller, in which it developes a thrust in the direction of advance, into light, moderate and heavy loadings. The division is based on the degree to which the flow is influenced by the action of the propeller. For the heavily loaded propeller no

  11. GPM and TRMM Radar Vertical Profiles and Impact on Large-scale Variations of Surface Rain

    Science.gov (United States)

    Wang, J. J.; Adler, R. F.

    2017-12-01

    Previous studies by the authors using Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) data have shown that TRMM Precipitation Radar (PR) and GPM Dual-Frequency Precipitation Radar (DPR) surface rain estimates do not have corresponding amplitudes of inter-annual variations over the tropical oceans as do passive microwave observations by TRMM Microwave Imager (TMI) and GPM Microwave Imager (GMI). This includes differences in surface temperature-rainfall variations. We re-investigate these relations with the new GPM Version 5 data with an emphasis on understanding these differences with respect to the DPR vertical profiles of reflectivity and rainfall and the associated convective and stratiform proportions. For the inter-annual variation of ocean rainfall from both passive microwave (TMI and GMI) and active microwave (PR and DPR) estimates, it is found that for stratiform rainfall both TMI-PR and GMI-DPR show very good correlation. However, the correlation of GMI-DPR is much higher than TMI-PR in convective rainfall. The analysis of vertical profile of PR and DPR rainfall during the TRMM and GPM overlap period (March-August, 2014) reveals that PR and DPR have about the same rainrate at 4km and above, but PR rainrate is more than 10% lower that of DPR at the surface. In other words, it seems that convective rainfall is better defined with DPR near surface. However, even though the DPR results agree better with the passive microwave results, there still is a significant difference, which may be a result of DPR retrieval error, or inherent passive/active retrieval differences. Monthly and instantaneous GMI and DPR data need to be analyzed in details to better understand the differences.

  12. Assessment of spatiotemporal variations in the fluvial wash-load component in the 21st century with regard to GCM climate change scenarios

    International Nuclear Information System (INIS)

    Mouri, Goro

    2015-01-01

    For stream water, in which a relationship exists between wash-load concentration and discharge, an estimate of fine-sediment delivery may be obtained from a traditional fluvial wash-load rating curve. Here, we demonstrate that the remaining wash-load material load can be estimated from a traditional empirical principle on a nationwide scale. The traditional technique was applied to stream water for the whole of Japan. Four typical GCMs were selected from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble to provide the driving fields for the following regional climate models to assess the wash-load component based on rating curves: the Model for Interdisciplinary Research on Climate (MIROC), the Meteorological Research Institute Atmospheric General Circulation Model (MRI-GCM), the Hadley Centre Global Environment Model (HadGEM) and the Geophysical Fluid Dynamics Laboratory (GFDL) climate model. The simulations consisted of an ensemble, including multiple physics configurations and different Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5), which was used to produce monthly datasets for the whole country of Japan. The impacts of future climate changes on fluvial wash load in Japanese stream water were based on the balance of changes in hydrological factors. The annual and seasonal variations of the fluvial wash load were assessed from the result of the ensemble analysis in consideration of the Greenhouse Gas (GHG) emission scenarios. The determined results for the amount of wash load increase range from approximately 20 to 110% in the 2040s, especially along part of the Pacific Ocean and the Sea of Japan regions. In the 2090s, the amount of wash load is projected to increase by more than 50% over the whole of Japan. The assessment indicates that seasonal variation is particularly important because the rainy and typhoon seasons, which include extreme events, are the dominant seasons. Because fluvial wash-load-component turbidity

  13. Assessment of spatiotemporal variations in the fluvial wash-load component in the 21st century with regard to GCM climate change scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Mouri, Goro, E-mail: mouri@rainbow.iis.u-tokyo.ac.jp

    2015-11-15

    For stream water, in which a relationship exists between wash-load concentration and discharge, an estimate of fine-sediment delivery may be obtained from a traditional fluvial wash-load rating curve. Here, we demonstrate that the remaining wash-load material load can be estimated from a traditional empirical principle on a nationwide scale. The traditional technique was applied to stream water for the whole of Japan. Four typical GCMs were selected from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble to provide the driving fields for the following regional climate models to assess the wash-load component based on rating curves: the Model for Interdisciplinary Research on Climate (MIROC), the Meteorological Research Institute Atmospheric General Circulation Model (MRI-GCM), the Hadley Centre Global Environment Model (HadGEM) and the Geophysical Fluid Dynamics Laboratory (GFDL) climate model. The simulations consisted of an ensemble, including multiple physics configurations and different Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5), which was used to produce monthly datasets for the whole country of Japan. The impacts of future climate changes on fluvial wash load in Japanese stream water were based on the balance of changes in hydrological factors. The annual and seasonal variations of the fluvial wash load were assessed from the result of the ensemble analysis in consideration of the Greenhouse Gas (GHG) emission scenarios. The determined results for the amount of wash load increase range from approximately 20 to 110% in the 2040s, especially along part of the Pacific Ocean and the Sea of Japan regions. In the 2090s, the amount of wash load is projected to increase by more than 50% over the whole of Japan. The assessment indicates that seasonal variation is particularly important because the rainy and typhoon seasons, which include extreme events, are the dominant seasons. Because fluvial wash-load-component turbidity

  14. Effect of cold plasma pre-treatment on photocatalytic activity of 3D fabric loaded with nano-photocatalysts: Response surface methodology

    Science.gov (United States)

    Ghoreishian, Seyed Majid; Badii, Khashayar; Norouzi, Mohammad; Malek, Kaveh

    2016-03-01

    In this study, the physico-chemical effects occasioned by the cold plasma discharge (CPD) on the photo-decolorization of Reactive Orange 16 (RO16) by 3D fabrics (spacer fabrics) loaded with ZnO:TiO2 nano-photocatalysts (nphs) were optimized via response surface methodology (RSM). CPD was employed to improve the surface characteristics of the spacer fabrics for nphs loading. Surface morphology and color variation were studied utilizing scanning electron microscopy (SEM) and CIE-Lab system, respectively. The effect of CPD on the wetting ability of the spacer fabrics was examined using dynamic adsorption measurement (DAM). Also, X-ray fluorescence (XRF) was utilized to investigate the durability of the nphs on the spacer fabrics. All the experiments were implemented in a Box-Behnken design (BBD) with three independent variables (CPD treatment time, dye concentration and irradiation time) in order to optimize the decolorization of RO16. The anticipated values of the decolorization efficiency were found to be in excellent agreement with the experimental values (R2 = 0.9996, Adjusted R2 = 0.9992). The kinetic analysis demonstrated that the photocatalytic decolorization followed the Langmuir-Hinshelwood kinetic model. In conclusion, this heterogeneous photocatalytic process is capable of decolorizing and mineralizing azoic reactive dye in textile wastewater. Moreover, the results confirmed that RSM based on the BBD was a suitable method to optimize the operating conditions of RO16 degradation.

  15. Temporal variation of 228Ra in the near-surface Gulf of Mexico

    International Nuclear Information System (INIS)

    Reid, F.D.; Moore, W.S.; Sackett, W.M.

    1979-01-01

    The Mn-fiber technique for extracting radium from seawater has proved useful for studying the marine geochemistry of 228 Ra. In the Gulf of Mexico, this technique was used to measure the surface and near-surface distribution of 226 Ra and 228 Ra. The observed surface distribution of 228 Ra, and particularly the radium activity ratio (228/226) can be explained by known circulation patterns, or, when local surface currents are not well understood, may provide insight into their general characteristics. The radium activity ratio has increased from 0.5 in 1968 to 0.7 in 1973 in the surface Gulf of Mexico. This observed increase cannot be attributed to known anthropogenic or natural source perturbations within the Caribbean Sea-Gulf of Mexico system. Possible causes include a change in the residence time for near-surface water, or variations in the relative dominance of the two eastern Caribbean; the North Equatorial Current and the Guiana Current. The temporal distribution of 228 Ra is unstable and naturally variable over a time period less than or equal to five years in the Gulf of Mexico and by extrapolation, the Caribbean Sea. Therefore, its usefulness in calculations of eddy diffusion coefficients for these regions is greatly diminished. (Auth.)

  16. Spatial variation in spoil and vegetative characteristics of pastures on reclaimed surface mined land

    International Nuclear Information System (INIS)

    Teutsch, C.D.; Collins, M.; Ditsch, D.C.

    1999-01-01

    Kentucky has large areas of reclaimed surface mined land that could provide grazing for livestock. Research is needed to determine optimal stocking densities and to evaluate the sustainability of such grazing systems for this region. A long-term grazing study was initiated in 1997 on 151 ha of reclaimed land near Chavies, KY to determine spatial and temporal variation with stocking densities of 0, 0.28, 0.42, or 0.83 beef cow-calf units/ha. Global Positioning System and GIS technologies were used to establish pasture boundaries, locate permanent sampling markers at a density of 1 per 0.4 ha, and interpolate maps of physical, spoil, and vegetable pasture characteristics. Herbage and spoil samples were collected around the permanent markers in May of 1997. Stepwise regression was used to determine factors affecting the vegetative characteristics of the sites. Biomass density ranged from 0 to 2500 kg/ha with a mean of 570 kg/ha. Factors affecting biomass included legume and weed proportions in the sward, grazing activity, soil potassium, elevation, and potential acidity, cumulatively accounting for 32% of the variation. Ground cover ranged from 10 to 100% with an average of 74%. Soil pH, potassium, and grass in the sward accounted for 14% of the variation in ground cover. Legumes made up 0 to 61% of the sward with a mean of 13% over the pasture area. Variables affecting the amount of legume in the sward included biomass density, slope, elevation, pH, and stocking density, together accounting for 21% of the variation. Spatial variation in the physical, spoil, and vegetative characteristics of the pastures was large. Overall, regression accounted for a limited amount of the variation in the vegetative characteristics of the site indicating that other important variables exist

  17. Lateral variation in crustal and mantle structure in Bay of Bengal based on surface wave data

    Science.gov (United States)

    Kumar, Amit; Mukhopadhyay, Sagarika; Kumar, Naresh; Baidya, P. R.

    2018-01-01

    Surface waves generated by earthquakes that occurred near Sumatra, Andaman-Nicobar Island chain and Sunda arc are used to estimate crustal and upper mantle S wave velocity structure of Bay of Bengal. Records of these seismic events at various stations located along the eastern coast of India and a few stations in the north eastern part of India are selected for such analysis. These stations lie within regional distance of the selected earthquakes. The selected events are shallow focused with magnitude greater than 5.5. Data of 65, 37, 36, 53 and 36 events recorded at Shillong, Bokaro, Visakhapatnam, Chennai and Trivandrum stations respectively are used for this purpose. The ray paths from the earthquake source to the recording stations cover different parts of the Bay of Bengal. Multiple Filtering Technique (MFT) is applied to compute the group velocities of surface waves from the available data. The dispersion curves thus obtained for this data set are within the period range of 15-120 s. Joint inversion of Rayleigh and Love wave group velocity is carried out to obtain the subsurface information in terms of variation of S wave velocity with depth. The estimated S wave velocity at a given depth and layer thickness can be considered to be an average value for the entire path covered by the corresponding ray paths. However, we observe variation in the value of S wave velocity and layer thickness from data recorded at different stations, indicating lateral variation in these two parameters. Thick deposition of sediments is observed along the paths followed by surface waves to Shillong and Bokaro stations. Sediment thickness keeps on decreasing as the surface wave paths move further south. Based on velocity variation the sedimentary layer is further divided in to three parts; on top lay unconsolidated sediment, underlain by consolidated sediment. Below this lies a layer which we consider as meta-sediments. The thickness and velocity of these layers decrease from north

  18. Natural compositional variation of the river Meuse (Maas) suspended load: a 13 ka bulk geochemical record from the upper Kreftenheye and Betuwe Formations in northern Limburg

    NARCIS (Netherlands)

    Tebbens, L.A.; Veldkamp, A.; Kroonenberg, S.B.

    2000-01-01

    Unambiguously pristine and largely unpolluted sediments from the Late Weichselian and Holocene infillings of the Meuse residual channels in northern Limburg (the Netherlands) have been sampled to determine the natural compositional variation of the river’s suspended load. Bulk geochemical and

  19. Color Variation on the Surfaces of Jupiter’s Greek and Trojan Asteroids

    Science.gov (United States)

    Chatelain, Joseph; Trilling, David E.; Emery, Joshua P.

    2017-10-01

    The L4 and L5 Lagrange points of Jupiter are populated with thousands of known, and possibly hundreds of thousands of unknown, Greek and Trojan Asteroids. Understanding the environmental and weathering conditions experienced by these objects over their lifetimes could constrain formation models for the Solar System. In an effort to shine some light on this issue, we have collected partial, simultaneous, lightcurves in both Johnson-Cousins V and I filters for a dozen large Jupiter Trojans. We found significant signs of color variation over the surfaces of four of these objects, and more subtle signs on an additional four. The most convincing examples of variation occur on (4709) Ennomos and (4833) Meges. Such a variation in color with rotation likely implies a large surface feature such as a recent crater. That such a high fraction of observed Trojans display these signatures could imply a more active collisional history for Jupiter Trojans than previously thought. It is therefore likely that one or more of the targets for the Lucy mission will have experienced a large, relatively recent, cratering event. This may help us obtain a much more in-depth understanding of the evolutionary processes ongoing for the Jupiter Trojan populations.

  20. The impact of land and sea surface variations on the Delaware sea breeze at local scales

    Science.gov (United States)

    Hughes, Christopher P.

    The summertime climate of coastal Delaware is greatly influenced by the intensity, frequency, and location of the local sea breeze circulation. Sea breeze induced changes in temperature, humidity, wind speed, and precipitation influence many aspects of Delaware's economy by affecting tourism, farming, air pollution density, energy usage, and the strength, and persistence of Delaware's wind resource. The sea breeze front can develop offshore or along the coastline and often creates a near surface thermal gradient in excess of 5°C. The purpose of this dissertation is to investigate the dynamics of the Delaware sea breeze with a focus on the immediate coastline using observed and modeled components, both at high resolutions (~200m). The Weather Research and Forecasting model (version 3.5) was employed over southern Delaware with 5 domains (4 levels of nesting), with resolutions ranging from 18km to 222m, for June 2013 to investigate the sensitivity of the sea breeze to land and sea surface variations. The land surface was modified in the model to improve the resolution, which led to the addition of land surface along the coastline and accounted for recent urban development. Nine-day composites of satellite sea surface temperatures were ingested into the model and an in-house SST forcing dataset was developed to account for spatial SST variation within the inland bays. Simulations, which include the modified land surface, introduce a distinct secondary atmospheric circulation across the coastline of Rehoboth Bay when synoptic offshore wind flow is weak. Model runs using high spatial- and temporal-resolution satellite sea surface temperatures over the ocean indicate that the sea breeze landfall time is sensitive to the SST when the circulation develops offshore. During the summer of 2013 a field campaign was conducted in the coastal locations of Rehoboth Beach, DE and Cape Henlopen, DE. At each location, a series of eleven small, autonomous thermo-sensors (i

  1. Linkage design effect on the reliability of surface micromachined microengines driving a load

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, D.M.; Peterson, K.A.; Irwin, L.W.; Tangyunyong, P.; Miller, W.M.; Eaton, W.P.; Smith, N.F.; Rodgers, M.S.

    1998-08-01

    The reliability of microengines is a function of the design of the mechanical linkage used to connect the electrostatic actuator to the drive. The authors have completed a series of reliability stress tests on surface micromachined microengines driving an inertial load. In these experiments, the authors used microengines that had pin mechanisms with guides connecting the drive arms to the electrostatic actuators. Comparing this data to previous results using flexure linkages revealed that the pin linkage design was less reliable. The devices were stressed to failure at eight frequencies, both above and below the measured resonance frequency of the microengine. Significant amounts of wear debris were observed both around the hub and pin joint of the drive gear. Additionally, wear tracks were observed in the area where the moving shuttle rubbed against the guides of the pin linkage. At each frequency, they analyzed the statistical data yielding a lifetime (t{sub 50}) for median cycles to failure and {sigma}, the shape parameter of the distribution. A model was developed to describe the failure data based on fundamental wear mechanisms and forces exhibited in mechanical resonant systems. The comparison to the model will be discussed.

  2. Damage identification from uniform load surface using continuous and stationary wavelet transforms

    Directory of Open Access Journals (Sweden)

    M. Masoumi

    Full Text Available Derived from flexibility matrix, Uniform Load Surface (ULS is used to identify damages in beam-type structures. This method is beneficial in terms of more participating the lower order modes and having less prone to noise and irregularities in the measured data in comparison with the original flexibility matrix technique. Therefore, these characteristics make this approach a practical tool in the field of damage identification. This paper presents a procedure to employ stationary wavelet transform multi-resolution analysis (SWT-MRA to refine ULS obtained from the damaged structure and then using continuous wavelet transform (CWT for localizing the discontinuity of improved ULS as a sign of damage site. Evaluation of the proposed method is carried out by examining a cantilever beam as a numerical case, where the ULS is formed by using mode shapes of damaged beam and two kinds of wavelets (i.e. symmetrical 4 and bior 6.8 is applied for discerning the induced crack. Moreover, a laboratory test is conducted on a free-free beam to experimentally evaluate the practicability of the technique.

  3. METHANE DRY REFORMING OVER Ni SUPPORTED ON PINE SAWDUST ACTIVATED CARBON: EFFECTS OF SUPPORT SURFACE PROPERTIES AND METAL LOADING

    Directory of Open Access Journals (Sweden)

    Rafael García

    2015-05-01

    Full Text Available The influence of metal loading and support surface functional groups (SFG on methane dry reforming (MDR over Ni catalysts supported on pine-sawdust derived activated carbon were studied. Using pine sawdust as the catalyst support precursor, the smallest variety and lowest concentration of SFG led to best Ni dispersion and highest catalytic activity, which increased with Ni loading up to 3 Ni atoms nm-2. At higher Ni loading, the formation of large metal aggregates was observed, consistent with a lower "apparen" surface area and a decrease in catalytic activity. The H2/CO ratio rose with increasing reaction temperature, indicating that increasingly important side reactions were taking place in addition to MDR.

  4. Variation in Pockels constants of silicate glass-ceramics prepared by perfect surface crystallization

    Science.gov (United States)

    Takano, Kazuya; Takahashi, Yoshihiro; Miyazaki, Takamichi; Terakado, Nobuaki; Fujiwara, Takumi

    2018-01-01

    We investigated the Pockels effect in polycrystalline materials consisting of highly oriented polar fresnoite-type Sr2TiSi2O8 fabricated using perfectly surface-crystallized glass-ceramics (PSC-GCs). The chemical composition of the precursor glass was shown to significantly affect the crystallized texture, e.g., the crystal orientation and appearance of amorphous nanoparasites in the domains, resulting in variations in the Pockels constants. Single crystals exhibiting spontaneous polarization possessed large structural anisotropy, leading to a strong dependence of the nonlinear-optical properties on the direction of polarized light. This study suggests that variations in the Pockels constants (r13 and r33) and tuning of the r13/r33 ratio can be realized in PSC-GC materials.

  5. A Variational Model for Two-Phase Immiscible Electroosmotic Flow at Solid Surfaces

    KAUST Repository

    Shao, Sihong

    2012-01-01

    We develop a continuum hydrodynamic model for two-phase immiscible flows that involve electroosmotic effect in an electrolyte and moving contact line at solid surfaces. The model is derived through a variational approach based on the Onsager principle of minimum energy dissipation. This approach was first presented in the derivation of a continuum hydrodynamic model for moving contact line in neutral two-phase immiscible flows (Qian, Wang, and Sheng, J. Fluid Mech. 564, 333-360 (2006)). Physically, the electroosmotic effect can be formulated by the Onsager principle as well in the linear response regime. Therefore, the same variational approach is applied here to the derivation of the continuum hydrodynamic model for charged two-phase immiscible flows where one fluid component is an electrolyte exhibiting electroosmotic effect on a charged surface. A phase field is employed to model the diffuse interface between two immiscible fluid components, one being the electrolyte and the other a nonconductive fluid, both allowed to slip at solid surfaces. Our model consists of the incompressible Navier-Stokes equation for momentum transport, the Nernst-Planck equation for ion transport, the Cahn-Hilliard phase-field equation for interface motion, and the Poisson equation for electric potential, along with all the necessary boundary conditions. In particular, all the dynamic boundary conditions at solid surfaces, including the generalized Navier boundary condition for slip, are derived together with the equations of motion in the bulk region. Numerical examples in two-dimensional space, which involve overlapped electric double layer fields, have been presented to demonstrate the validity and applicability of the model, and a few salient features of the two-phase immiscible electroosmotic flows at solid surface. The wall slip in the vicinity of moving contact line and the Smoluchowski slip in the electric double layer are both investigated. © 2012 Global-Science Press.

  6. Use of 198 Au, with surface labelling, in the study of solid transport by bed load in large natural channels

    International Nuclear Information System (INIS)

    Nakahira, S.

    1987-01-01

    The present study aims to present a method of measuring the bed load transport using a radioisotope technique in large natural channels. This study describes the basic principles of radioisotope application in this field, emphasizing the use of 198 Au for surface labelling of a natural sediment. Moreover, it presents the theoretical aspects, critical analysis, recommendations and comments on the methodology proposed. (author)

  7. Bone reactions adjacent to titanium implants with different surface characteristics subjected to static load. A study in the dog (II)

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2001-01-01

    The purpose of the present study was to compare bone reactions adjacent to titanium implants with either a titanium plasma-sprayed (TPS) or a machined surface subjected to lateral static loading induced by an expansion force. In 3 labrador dogs, the 2nd, 3rd and 4th mandibular premolars were...

  8. Experimental demonstration of CMOS-compatible long-range dielectric-loaded surface plasmon-polariton waveguides (LR-DLSPPWs)

    DEFF Research Database (Denmark)

    Zektzer, Roy; Desiatov, Boris; Mazurski, Noa

    2015-01-01

    We demonstrate the design, fabrication and experimental characterization of long-range dielectric-loaded surface plasmon-polariton waveguides (LR-DLSPPWs) that are compatible with complementary metal-oxide semiconductor (CMOS) technology. The demonstrated waveguides feature good mode confinement...

  9. Relationship of post-fire ground cover to surface fuel loads and consumption in longleaf pine ecosystems

    Science.gov (United States)

    Andrew T. Hudak; Roger D. Ottmar; Robert E. Vihnanek; Clint S. Wright

    2014-01-01

    The RxCADRE research team collected multi-scale measurements of pre-, during, and post-fire variables on operational prescribed fires conducted in 2008, 2011, and 2012 in longleaf pine ecosystems in the southeastern USA. Pre- and post-fire surface fuel loads were characterized in alternating pre- and post-fire clip plots systematically established within burn units....

  10. The effect of salvage logging on surface fuel loads and fuel moisture in beetle-infested lodgepole pine forests

    Science.gov (United States)

    Paul R. Hood; Kellen N. Nelson; Charles C. Rhoades; Daniel B. Tinker

    2017-01-01

    Widespread tree mortality from mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) outbreaks has prompted forest management activities to reduce crown fire hazard in the Rocky Mountain region. However, little is known about how beetle-related salvage logging and biomass utilization options affect woody surface fuel loads and fuel moisture dynamics. We compared...

  11. Surface acoustic load sensing using a face-shear PIN-PMN-PT single-crystal resonator.

    Science.gov (United States)

    Kim, Kyungrim; Zhang, Shujun; Jiang, Xiaoning

    2012-11-01

    Pb(In(0.5)Nb(0.5))O(3)-Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PIN-PMN-PT) resonators for surface acoustic load sensing are presented in this paper. Different acoustic loads are applied to thickness mode, thickness-shear mode, and face-shear mode resonators, and the electrical impedances at resonance and anti-resonance frequencies are recorded. More than one order of magnitude higher sensitivity (ratio of electrical impedance change to surface acoustic impedance change) at the resonance is achieved for the face-shear-mode resonator compared with other resonators with the same dimensions. The Krimholtz, Leedom, and Matthaei (KLM) model is used to verify the surface acoustic loading effect on the electrical impedance spectrum of face-shear PIN-PMN-PT single-crystal resonators. The demonstrated high sensitivity of face-shear mode resonators to surface loads is promising for a broad range of applications, including artificial skin, biological and chemical sensors, touch screens, and other touch-based sensors.

  12. The Variation of Planetary Surfaces' Structure and Size Distribution with Depth

    Science.gov (United States)

    Charalambous, C. A.; Pike, W. T.

    2014-12-01

    The particle, rock and boulder size distribution of a planetary surface bring important implications not only to crucial aspects of future missions but also to the better understanding of planetary and earth sciences. By exploiting a novel statistical model, the evolution of particle fragmentation phenomena can be understood in terms of a descriptive maturity index, a measure of the number of fragmentation events that have produced the soil. This statistical model, which is mathematically constructed via fundamental physical principles, has been validated by terrestrial mineral grinding data and impact experiments. Applying the model to planetary surfaces, the number of fragmentation events is determined by production function curves that quantify the degree of impact cratering. The model quantifies the variation of the maturity index of the regolith with depth, with a high maturity index at the surface decreasing to a low index corresponding to the megaregolith of a blocky population and fractured bedrock. The measured lunar and martian particle size distributions at the surface is well matched by the model over several orders of magnitude. The continuous transition invoked by the model can be furthermore synthesised to provide temporal and spatial visualisations of the internal architecture of the Martian and Lunar regolith. Finally, the model is applied to the risk assessment and success criteria of future mission landings as well as drilling on planetary surfaces. The solutions to a variety of planetary fragmentation related problems can be found via exact mathematical foundations or through simulations using the particle population provided by the model's maturation.

  13. Does quality control matter? Surface urban heat island intensity variations estimated by satellite-derived land surface temperature products

    Science.gov (United States)

    Lai, Jiameng; Zhan, Wenfeng; Huang, Fan; Quan, Jinling; Hu, Leiqiu; Gao, Lun; Ju, Weimin

    2018-05-01

    The temporally regular and spatially comprehensive monitoring of surface urban heat islands (SUHIs) have been extremely difficult, until the advent of satellite-based land surface temperature (LST) products. However, these LST products have relatively higher errors compared to in situ measurements. This has resulted in comparatively inaccurate estimations of SUHI indicators and, consequently, may have distorted interpretations of SUHIs. Although reports have shown that LST qualities are important for SUHI interpretations, systematic investigations of the response of SUHI indicators to LST qualities across cities with dissimilar bioclimates are rare. To address this issue, we chose eighty-six major cities across mainland China and analyzed SUHI intensity (SUHII) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) LST data. The LST-based SUHII differences due to inclusion or exclusion of MODIS quality control (QC) flags (i.e., ΔSUHII) were evaluated. Our major findings included, but are not limited to, the following four aspects: (1) SUHIIs can be significantly impacted by MODIS QC flags, and the associated QC-induced ΔSUHIIs generally accounted for 24.3% (29.9%) of the total SUHII value during the day (night); (2) the ΔSUHIIs differed between seasons, with considerable differences between transitional (spring and autumn) and extreme (summer and winter) seasons; (3) significant discrepancies also appeared among cities located in northern and southern regions, with northern cities often possessing higher annual mean ΔSUHIIs. The internal variations of ΔSUHIIs within individual cities also showed high heterogeneity, with ΔSUHII variations that generally exceeded 5.0 K (3.0 K) in northern (southern) cities; (4) ΔSUHIIs were negatively related to SUHIIs and cloud cover percentages (mostly in transitional seasons). No significant relationship was found in the extreme seasons. Our findings highlight the need to be extremely cautious when using LST

  14. THE EFFECTS OF SURFACE-INDUCED LOADS ON FOREARM MUSCLE ACTIVITY DURING STEERING A BICYCLE

    Directory of Open Access Journals (Sweden)

    Pinar Arpinar-Avsar

    2013-09-01

    Full Text Available On the bicycle, the human upper extremity has two essential functions in steering the bicycle and in supporting the body. Through the handlebar, surface- induced loads are transmitted to the hand and arm of the bicycle rider under vibration exposure conditions. Thus, the purpose of the study was to investigate the effect of vibration exposure on forearm muscle activity for different road surfaces (i.e. smooth road, concrete stone pavement, rough road and for different bicycles. Ten subjects participated in experiments and two types of bicycles, i.e. Road Bike (RB and Mountain Bike (MTB are compared. The acceleration magnitudes were dominant along x and z-axes. The r.m.s acceleration values in the z direction at the stem of MTB were at most 2.56, 7.04 and 10.76 m·s-2 when pedaling respectively on asphalt road, concrete pavement and rough road. In the case of RB the corresponding values were respectively 4.43, 11.75 and 27.31 m·s-2. The cumulative normalized muscular activity levels during MTB trials on different surfaces had the same tendency as with acceleration amplitudes and have ranked in the same order from lowest to highest value. Although road bike measurements have resulted in a similar trend of increment, the values computed for rough road trials were higher than those in MTB trials. During rough road measurements on MTB, rmsEMG of extensor muscles reached a value corresponding to approximately 50% of MVC (Maximum Voluntary Contraction. During RB trials performed on rough road conditions, rmsEMG (%MVC values for the forearm flexor muscles reached 45.8% of their maximal. The level of muscular activity of forearm muscles in controlling handlebar movements has been observed to be enhanced by the increase in the level of vibration exposed on the bicycle. Since repeated forceful gripping and pushing forces to a handle of a vibratory tool can create a risk of developing circulatory, neurological, or musculoskeletal disorder, a bicycle rider

  15. The mechanical interactions between an American football cleat and playing surfaces in-situ at loads and rates generated by elite athletes: a comparison of playing surfaces.

    Science.gov (United States)

    Kent, Richard; Forman, Jason L; Crandall, Jeff; Lessley, David

    2015-03-01

    This study quantified the mechanical interactions between an American football cleat and eight surfaces used by professional American football teams. Loading conditions were applied with a custom-built testing apparatus designed to represent play-relevant maneuvers of elite athletes. Two natural grass and six infill artificial surfaces were tested with the cleated portion of a shoe intended for use on either surface type. In translation tests with a 2. 8-kN vertical load, the grass surfaces limited the horizontal force on the cleats by tearing. This tearing was not observed with the artificial surfaces, which allowed less motion and generated greater horizontal force (3.2 kN vs. 4.5 kN, p force on the natural surfaces than on the artificial surfaces (2.4 kN vs. 3.0 kN, p force-limiting mechanism inherent to natural grass surfaces. Future work should consider implications of these findings for performance and injury risk and should evaluate the findings' sensitivity to cleat pattern and playing conditions.

  16. The shape and surface variation of 2 Pallas from the Hubble Space Telescope.

    Science.gov (United States)

    Schmidt, B E; Thomas, P C; Bauer, J M; Li, J-Y; McFadden, L A; Mutchler, M J; Radcliffe, S C; Rivkin, A S; Russell, C T; Parker, J Wm; Stern, S A

    2009-10-09

    We obtained Hubble Space Telescope images of 2 Pallas in September 2007 that reveal distinct color and albedo variations across the surface of this large asteroid. Pallas's shape is an ellipsoid with radii of 291 (+/-9), 278 (+/-9), and 250 (+/-9) kilometers, implying a density of 2400 (+/-250) kilograms per cubic meter-a value consistent with a body that formed from water-rich material. Our observations are consistent with the presence of an impact feature, 240 (+/-25) kilometers in diameter, within Pallas's ultraviolet-dark terrain. Our observations imply that Pallas is an intact protoplanet that has undergone impact excavation and probable internal alteration.

  17. Assessment of spatiotemporal variations in the fluvial wash-load component in the 21st century with regard to GCM climate change scenarios.

    Science.gov (United States)

    Mouri, Goro

    2015-11-15

    For stream water, in which a relationship exists between wash-load concentration and discharge, an estimate of fine-sediment delivery may be obtained from a traditional fluvial wash-load rating curve. Here, we demonstrate that the remaining wash-load material load can be estimated from a traditional empirical principle on a nationwide scale. The traditional technique was applied to stream water for the whole of Japan. Four typical GCMs were selected from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble to provide the driving fields for the following regional climate models to assess the wash-load component based on rating curves: the Model for Interdisciplinary Research on Climate (MIROC), the Meteorological Research Institute Atmospheric General Circulation Model (MRI-GCM), the Hadley Centre Global Environment Model (HadGEM) and the Geophysical Fluid Dynamics Laboratory (GFDL) climate model. The simulations consisted of an ensemble, including multiple physics configurations and different Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5), which was used to produce monthly datasets for the whole country of Japan. The impacts of future climate changes on fluvial wash load in Japanese stream water were based on the balance of changes in hydrological factors. The annual and seasonal variations of the fluvial wash load were assessed from the result of the ensemble analysis in consideration of the Greenhouse Gas (GHG) emission scenarios. The determined results for the amount of wash load increase range from approximately 20 to 110% in the 2040s, especially along part of the Pacific Ocean and the Sea of Japan regions. In the 2090s, the amount of wash load is projected to increase by more than 50% over the whole of Japan. The assessment indicates that seasonal variation is particularly important because the rainy and typhoon seasons, which include extreme events, are the dominant seasons. Because fluvial wash-load-component turbidity

  18. Relevance of decadal variations in surface radiative fluxes for climate change

    Science.gov (United States)

    Wild, Martin

    2013-05-01

    Recent evidence suggests that radiative fluxes incident at Earth's surface are not stable over time but undergo significant changes on decadal timescales. This is not only found in the thermal spectral range, where an increase in the downwelling flux is expected due to the increasing greenhouse effect, but also in the solar spectral range. Observations suggest that surface solar radiation, after a period of decline from the 1950s to the 1980s ("global dimming"), reversed into a "brightening" since the mid-1980s at widespread locations, often in line with changes in anthropogenic air pollution. These decadal variations observed in both solar and thermal surface radiative fluxes have the potential to affect various aspects of climate change. Discussed here are specifically the evidence for potential effects on global warming, as seen in asymmetries in hemispheric warming rates as well as in differences in the decadal warming rates over land and oceans. These variations in observed warming rates fit well to our conceptual understanding of how aerosol and greenhouse gas-induced changes in the surface radiative fluxes should affect global warming. Specifically, on the Northern Hemisphere, the suppression of warming from the 1950s to the 1980s fits to the concurrent dimming and increasing air pollution, while the accelerated warming from the 1980s to 2000 matches with the brightening and associated reduction in pollution levels. The suppression of warming from the 1950s to the 1980s is even somewhat stronger over oceans than over land, in line with the conceptual idea that aerosol-induced dimming and brightening tendencies may be enhanced through cloud aerosol interactions particularly over the pristine ocean areas. On the Southern Hemisphere, the absence of significant pollution levels as well as trend reversals therein, fit to the observed stable warming rates over the entire 1950 to 2000 period.

  19. Theoretical design and analysis of wideband active hard electromagnetic surfaces using non-Foster circuit loaded anisotropic metasurfaces

    Science.gov (United States)

    Li, Yunbo; Li, Aobo; Sievenpiper, Daniel

    2018-02-01

    The electromagnetic (EM) hard surface which can both support transverse electric and transverse magnetic surface wave modes has the important ability to reduce the EM blockage of metallic obstacles. We propose a method to design an electrically thin hard surface with wide bandwidth by loading with non-Foster elements. The wideband hard surface composed of an anisotropic impedance coating can be considered as a kind of active metasurface. We develop a method to determine the values of the loading non-Foster circuit which can minimize the dispersion of the unit cells. For this method, we derive accurate values for the loading non-Foster elements through theoretical analysis. We also determine the fundamental limitations on the bandwidth due to stability requirements. To verify our theoretical design, we simulate the transmission performance between the two ports on opposite sides of a metallic rhombus-shaped obstacle coated with the non-Foster based metasurface. The simulated results show that the blockage has been largely reduced over a broad bandwidth from 0.2 GHz to 1.5 GHz. Finally, we provide a discussion on how the resistive part of the non-Foster circuit can affect the performance of the wideband hard surface coating.

  20. Vibration and buckling characteristics of functionally graded nanoplates subjected to thermal loading based on surface elasticity theory

    Science.gov (United States)

    Ansari, R.; Ashrafi, M. A.; Pourashraf, T.; Sahmani, S.

    2015-04-01

    The buckling and vibration responses of nanoplates made of functionally graded materials (FGMs) subjected to thermal loading are studied in prebuckling domain with considering the effect of surface stress. To accomplish this purpose, Gurtin-Murdoch elasticity theory is incorporated into the classical plate theory to develop a non-classical plate model including the surface effects. The material properties of FGM nanoplate are considered to be graded in the thickness direction on the basis of the power law function. Hamilton's principle is utilized to derive size-dependent governing differential equations of motion and associated boundary conditions. Selected numerical results are presented to indicate the importance of surface stress effect. It is revealed that in the presence of surface stress effect, the influence of material property gradient index on the critical thermal buckling load is more prominent for FGM nanoplates with lower length-to-thickness ratios. Also, by increasing the natural frequency of FGM nanoplate, the role of surface stress effect in the value of critical thermal buckling load is more prominent.

  1. Crack-tip Stress Field of Fully Circumferential Surface Cracked Pipe Under Combined Tension and Thermal Loads

    International Nuclear Information System (INIS)

    Je, Jin Ho; Kim, Dong Jun; Kim, Yun Jae

    2014-01-01

    Under excessive plasticity, the fracture toughness of a material depends on its size and geometry. Under fully yielded conditions, the stresses in a material near its crack tip are not unique but rather depend on the geometry. Therefore, the single-parameter J-approach is limited to a high-constraint crack geometry. The JQ theory has been proposed for establishing the crack geometry constraints . This approach assumes that the crack-tip fields have two degrees of freedom. In this study, the crack-tip stress field of a fully circumferential surface-cracked pipe under combined loads is investigated on the basis of the JQ theory by using finite element analysis. The combined loads are a tensile axial force and the thermal gradient in the radial direction. Q-stresses of the crack geometry and its loading state are used to determine the constraint effects. The constraint effects of secondary loading are found to be greater than those of primary loading. Therefore, thermal shock is believed to be the most severe loading condition of constraint effects

  2. Spatiotemporal Variation in Surface Urban Heat Island Intensity and Associated Determinants across Major Chinese Cities

    Directory of Open Access Journals (Sweden)

    Juan Wang

    2015-03-01

    Full Text Available Urban heat islands (UHIs created through urbanization can have negative impacts on the lives of people living in cities. They may also vary spatially and temporally over a city. There is, thus, a need for greater understanding of these patterns and their causes. While previous UHI studies focused on only a few cities and/or several explanatory variables, this research provides a comprehensive and comparative characterization of the diurnal and seasonal variation in surface UHI intensities (SUHIIs across 67 major Chinese cities. The factors associated with the SUHII were assessed by considering a variety of related social, economic and natural factors using a regression tree model. Obvious seasonal variation was observed for the daytime SUHII, and the diurnal variation in SUHII varied seasonally across China. Interestingly, the SUHII varied significantly in character between northern and southern China. Southern China experienced more intense daytime SUHIIs, while the opposite was true for nighttime SUHIIs. Vegetation had the greatest effect in the day time in northern China. In southern China, annual electricity consumption and the number of public buses were found to be important. These results have important theoretical significance and may be of use to mitigate UHI effects.

  3. An assessment of surface emissivity variation effects on plasma uniformity analysis using IR cameras

    Science.gov (United States)

    Greenhalgh, Abigail; Showers, Melissa; Biewer, Theodore

    2017-10-01

    The Prototype-Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device operating at Oak Ridge National Laboratory (ORNL). Its purpose is to test plasma source and heating concepts for the planned Material Plasma Exposure eXperiment (MPEX), which has the mission to test the plasma-material interactions under fusion reactor conditions. In this device material targets will be exposed to high heat fluxes (>10 MW/m2). To characterize the heat fluxes to the target a IR thermography system is used taking up to 432 frames per second videos. The data is analyzed to determine the surface temperature on the target in specific regions of interest. The IR analysis has indicated a low level of plasma uniformity; the plasma often deposits more heat to the edge of the plate than the center. An essential parameter for IR temperature calculation is the surface emissivity of the plate (stainless steel). A study has been performed to characterize the variation in the surface emissivity of the plate as its temperature changes and its surface finish is modified by plasma exposure.

  4. Contributions to the geomagnetic secular variation from a reanalysis of core surface dynamics

    Science.gov (United States)

    Barrois, O.; Gillet, N.; Aubert, J.

    2017-10-01

    We invert for motions at the surface of Earth's core under spatial and temporal constraints that depart from the mathematical smoothings usually employed to ensure spectral convergence of the flow solutions. Our spatial constraints are derived from geodynamo simulations. The model is advected in time using stochastic differential equations coherent with the occurrence of geomagnetic jerks. Together with a Kalman filter, these spatial and temporal constraints enable the estimation of core flows as a function of length and time-scales. From synthetic experiments, we find it crucial to account for subgrid errors to obtain an unbiased reconstruction. This is achieved through an augmented state approach. We show that a significant contribution from diffusion to the geomagnetic secular variation should be considered even on short periods, because diffusion is dynamically related to the rapidly changing flow below the core surface. Our method, applied to geophysical observations over the period 1950-2015, gives access to reasonable solutions in terms of misfit to the data. We highlight an important signature of diffusion in the Eastern equatorial area, where the eccentric westward gyre reaches low latitudes, in relation with important up/downwellings. Our results also confirm that the dipole decay, observed over the past decades, is primarily driven by advection processes. Our method allows us to provide probability densities for forecasts of the core flow and the secular variation.

  5. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving X-ray crystal optics.

    Science.gov (United States)

    Stoupin, Stanislav; Antipov, Sergey; Butler, James E; Kolyadin, Alexander V; Katrusha, Andrey

    2016-09-01

    Fabrication and results of high-resolution X-ray topography characterization of diamond single-crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics are reported. The plates were fabricated by laser-cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. Wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking-curve topography. The variations of the rocking-curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.

  6. Spatiotemporal variation of surface shortwave forcing from fire-induced albedo change in interior Alaska

    Science.gov (United States)

    Huang, Shengli; Dahal, Devendra; Liu, Heping; Jin, Suming; Young, Claudia J.; Liu, Shuang; Liu, Shu-Guang

    2015-01-01

    The albedo change caused by both fires and subsequent succession is spatially heterogeneous, leading to the need to assess the spatiotemporal variation of surface shortwave forcing (SSF) as a component to quantify the climate impacts of high-latitude fires. We used an image reconstruction approach to compare postfire albedo with the albedo assuming fires had not occurred. Combining the fire-caused albedo change from the 2001-2010 fires in interior Alaska and the monthly surface incoming solar radiation, we examined the spatiotemporal variation of SSF in the early successional stage of around 10 years. Our results showed that while postfire albedo generally increased in fall, winter, and spring, some burned areas could show an albedo decrease during these seasons. In summer, the albedo increased for several years and then declined again. The spring SSF distribution did not show a latitudinal decrease from south to north as previously reported. The results also indicated that although the SSF is usually largely negative in the early successional years, it may not be significant during the first postfire year. The annual 2005-2010 SSF for the 2004 fire scars was -1.30, -4.40, -3.31, -4.00, -3.42, and -2.47 Wm-2. The integrated annual SSF map showed significant spatial variation with a mean of -3.15 Wm-2 and a standard deviation of 3.26 Wm-2, 16% of burned areas having positive SSF. Our results suggest that boreal deciduous fires would be less positive for climate change than boreal evergreen fires. Future research is needed to comprehensively investigate the spatiotemporal radiative and non-radiative forcings to determine the effect of boreal fires on climate.

  7. Estimating ammonium and nitrate load from septic systems to surface water bodies within ArcGIS environments

    Science.gov (United States)

    Zhu, Yan; Ye, Ming; Roeder, Eberhard; Hicks, Richard W.; Shi, Liangsheng; Yang, Jinzhong

    2016-01-01

    This paper presents a recently developed software, ArcGIS-based Nitrogen Load Estimation Toolkit (ArcNLET), for estimating nitrogen loading from septic systems to surface water bodies. The load estimation is important for managing nitrogen pollution, a world-wide challenge to water resources and environmental management. ArcNLET simulates coupled transport of ammonium and nitrate in both vadose zone and groundwater. This is a unique feature that cannot be found in other ArcGIS-based software for nitrogen modeling. ArcNLET is designed to be flexible for the following four simulating scenarios: (1) nitrate transport alone in groundwater; (2) ammonium and nitrate transport in groundwater; (3) ammonium and nitrate transport in vadose zone; and (4) ammonium and nitrate transport in both vadose zone and groundwater. With this flexibility, ArcNLET can be used as an efficient screening tool in a wide range of management projects related to nitrogen pollution. From the modeling perspective, this paper shows that in areas with high water table (e.g. river and lake shores), it may not be correct to assume a completed nitrification process that converts all ammonium to nitrate in the vadose zone, because observation data can indicate that substantial amount of ammonium enters groundwater. Therefore, in areas with high water table, simulating ammonium transport and estimating ammonium loading, in addition to nitrate transport and loading, are important for avoiding underestimation of nitrogen loading. This is demonstrated in the Eggleston Heights neighborhood in the City of Jacksonville, FL, USA, where monitoring well observations included a well with predominant ammonium concentrations. The ammonium loading given by the calibrated ArcNLET model can be 10-18% of the total nitrogen load, depending on various factors discussed in the paper.

  8. Seasonal Variations of the Surface Urban Heat Island in a Semi-Arid City

    Directory of Open Access Journals (Sweden)

    Sirous Haashemi

    2016-04-01

    Full Text Available The process of the surface urban heat island (SUHI varies with latitude, climate, topography and meteorological conditions. This study investigated the seasonal variability of SUHI in the Tehran metropolitan area, Iran, with respect to selected surface biophysical variables. Terra Moderate Resolution Imaging Spectroradiometer (MODIS Land Surface Temperature (LST was retrieved as nighttime LST data, while daytime LST was retrieved from Landsat 8 Thermal Infrared Sensor (TIRS using the split-window algorithm. Both data covered the time period from September 2013 to September 2015. To assess SUHI intensity, we employed three SUHI indicators, i.e., the LST difference of urban-rural, that of urban-agriculture and that of urban-water. Physical and biophysical surface variables, including land use and land cover (LULC, elevation, impervious surface (IS, fractional vegetation cover (FVC and albedo, were selected to estimate the relationship between LST seasonal variability and the surface properties. Results show that an inversion of the SUHI phenomenon (i.e., surface urban cool island existed at daytime with the maximal value of urban-rural LST difference of −4 K in March; whereas the maximal value of SUHI at nighttime yielded 3.9 K in May. When using the indicators of urban-agriculture and urban-water LST differences, the maximal value of SUHI was found to be 8.2 K and 15.5 K, respectively. Both results were observed at daytime, suggesting the role of bare soils in the inversion of the SUHI phenomenon with the urban-rural indicator. Maximal correlation was observed in the relationship between night LST and elevation in spring (coefficient: −0.76, night LST and IS in spring (0.60, night LST and albedo in winter (−0.53 and day LST with fractional vegetation cover in summer (−0.41. The relationship between all surface properties with LST possessed large seasonal variations, and thus, using these relationships for SUHI modeling may not be

  9. A modification to linearized theory for prediction of pressure loadings on lifting surfaces at high supersonic Mach numbers and large angles of attack

    Science.gov (United States)

    Carlson, H. W.

    1979-01-01

    A new linearized-theory pressure-coefficient formulation was studied. The new formulation is intended to provide more accurate estimates of detailed pressure loadings for improved stability analysis and for analysis of critical structural design conditions. The approach is based on the use of oblique-shock and Prandtl-Meyer expansion relationships for accurate representation of the variation of pressures with surface slopes in two-dimensional flow and linearized-theory perturbation velocities for evaluation of local three-dimensional aerodynamic interference effects. The applicability and limitations of the modification to linearized theory are illustrated through comparisons with experimental pressure distributions for delta wings covering a Mach number range from 1.45 to 4.60 and angles of attack from 0 to 25 degrees.

  10. Comprehensive nonlocal analysis of piezoelectric nanobeams with surface effects in bending, buckling and vibrations under magneto-electro-thermo-mechanical loading

    Science.gov (United States)

    Ebrahimi-Nejad, Salman; Boreiry, Mahya

    2018-03-01

    The bending, buckling and vibrational behavior of size-dependent piezoelectric nanobeams under thermo-magneto-mechano-electrical environment are investigated by performing a parametric study, in the presence of surface effects. The Gurtin-Murdoch surface elasticity and Eringen’s nonlocal elasticity theories are applied in the framework of Euler–Bernoulli beam theory to obtain a new non-classical size-dependent beam model for dynamic and static analyses of piezoelectric nanobeams. In order to satisfy the surface equilibrium equations, cubic variation of stress with beam thickness is assumed for the bulk stress component which is neglected in classical beam models. Results are obtained for clamped - simply-supported (C-S) and simply-supported - simply-supported (S-S) boundary conditions using a proposed analytical solution method. Numerical examples are presented to demonstrate the effects of length, surface effects, nonlocal parameter and environmental changes (temperature, magnetic field and external voltage) on deflection, critical buckling load and natural frequency for each boundary condition. Results of this study can serve as benchmarks for the design and analysis of nanostructures of magneto-electro-thermo-elastic materials.

  11. De novo biofilm community assembly from tap water source communities favors Nitrotoga over Nitrospira under elevated nitrite surface loading

    DEFF Research Database (Denmark)

    Kinnunen, Marta; Dechesne, Arnaud; Albrechtsen, Hans-Jørgen

    -through biofilm system to continuous immigration from a tap water metacommunity while applying different nitrite surface loading rates. After 63 days of operation, we extracted biofilms and analyzed the community composition via Illumina MiSeq targeting the 16S rRNA gene. Previous studies have shown...... in the metacommunity, Nitrotoga and Nitrospira were found at near equal abundances, in the biofilm community, elevated nitrite loading strongly selected for Nitrotoga over Nitrospira. The biofilms were also significantly different in their alpha-diversity (p... of the biofilm community decreased significantly (p=0.004) compared to the metacommunity. These observations indicate that the selection towards Nitrotoga and Nitrospira dominated community assembly under different nitrite loadings. Lastly, we compared our observations of community composition...

  12. Dynamic modeling of organophosphate pesticide load in surface water in the northern San Joaquin Valley watershed of California

    Science.gov (United States)

    Luo, Y.; Zhang, X.; Liu, X.; Ficklin, D. L.; Zhang, M.

    2008-12-01

    The hydrology, sediment, and pesticide transport components of the Soil and Water Assessment Tool (SWAT) were evaluated on the northern San Joaquin Valley watershed of California. The Nash Sutcliffe coefficients for monthly stream flow and sediment load ranged from 0.49 to 0.99 over the watershed during the study period of 1992 to 2005. The calibrated SWAT model was applied to simulate fate and transport processes of two organophosphate pesticides of diazinon and chlorpyrifos at watershed scale. The model generated satisfactory predictions of dissolved pesticide loads relative to the monitoring data. The model also showed great success in capturing spatial patterns of dissolved diazinon and chlorpyrifos loads according to the soil properties and landscape morphology over the large agricultural watershed. This study indicated that curve number was the major factor influencing the hydrology while pesticide fate and transport were mainly affected by surface runoff and pesticide application timing in the study area.

  13. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms.

    Science.gov (United States)

    Katiyatiya, C L F; Muchenje, V; Mushunje, A

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals (P cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale (P cows had significantly longer (P tick loads on different body parts and heat stress in Nguni cows.

  14. Analysis of ground motion due to moving surface loads induced by high-speed trains

    OpenAIRE

    Galvín, Pedro; Domínguez Abascal, José

    2007-01-01

    A three-dimensional time domain boundary element (BE) approach for the analysis of soil vibrations induced by high-speed moving loads is presented in this paper. An attenuation law is included in the formulation. By doing so, internal material damping can be taken into account. The characteristics of the BE model required for the study of travelling load problems are analysed. Thus, mesh size, type of elements, internal damping representation and the complete numerical approach are validated....

  15. Effects of the different frequencies and loads of ultrasonic surface rolling on surface mechanical properties and fretting wear resistance of HIP Ti–6Al–4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, G., E-mail: ligang_scut@outlook.com; Qu, S.G., E-mail: qusg@scut.edu.cn; Pan, Y.X.; Li, X.Q.

    2016-12-15

    Highlights: • Effects of MUSR frequency and load on surface properties of HIP Ti-6Al-4V investigated. • The grains in surface-modified layer were refined and appeared twins and many dense dislocations. • The hardened layer depth and surface residual stress of MUSR- treated samples were significantly improved. • MUSR- treated samples showed the good fretting friction and wear resistance. • The best microstructure and properties of surface-modified layer obtained by sample treated by 30 kHz and 900 N. - Abstract: The main purpose of this paper was to investigate the effects of the different frequencies and loads of multi-pass ultrasonic surface rolling (MUSR) on surface layer mechanical properties, microstructure and fretting friction and wear characteristics of HIP (hot isostatic pressing) Ti–6Al–4 V alloy. Some microscopic analysis methods (SEM, TEM and EDS) were used to characterize the modified surface layer of material after MUSR treatment. The results indicated that the material in sample surface layer experienced a certain extent plastic deformation, and accompanied by some dense dislocations and twins generation. Moreover surface microhardness and residual stress of samples treated by MUSR were also greatly improved compared with the untreated. The fretting friction and wear properties of samples treated by MUSR in different conditions are tested at 10 and 15 N in dry friction conditions. It could be found that friction coefficient and wear volume loss were significantly declined in the optimal result. The main wear mechanism of MUSR-treated samples included abrasive wear, adhesion and spalling.

  16. Dynamic modeling of organophosphate pesticide load in surface water in the northern San Joaquin Valley watershed of California

    International Nuclear Information System (INIS)

    Luo Yuzhou; Zhang Xuyang; Liu Xingmei; Ficklin, Darren; Zhang Minghua

    2008-01-01

    The hydrology, sediment, and pesticide transport components of the Soil and Water Assessment Tool (SWAT) were evaluated on the northern San Joaquin Valley watershed of California. The Nash-Sutcliffe coefficients for monthly stream flow and sediment load ranged from 0.49 to 0.99 over the watershed during the study period of 1992-2005. The calibrated SWAT model was applied to simulate fate and transport processes of two organophosphate pesticides of diazinon and chlorpyrifos at watershed scale. The model generated satisfactory predictions of dissolved pesticide loads relative to the monitoring data. The model also showed great success in capturing spatial patterns of dissolved diazinon and chlorpyrifos loads according to the soil properties and landscape morphology over the large agricultural watershed. This study indicated that curve number was the major factor influencing the hydrology while pesticide fate and transport were mainly affected by surface runoff and pesticide application and in the study area. - Major factors governing the instream loads of organophosphate pesticides are magnitude and timing of surface runoff and pesticide application

  17. Dynamic modeling of organophosphate pesticide load in surface water in the northern San Joaquin Valley watershed of California

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yuzhou [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States); Institute of Watershed Science and Environmental Ecology, Wenzhou Medical College, Wenzhou, 325000 (China); Zhang Xuyang [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States); Liu Xingmei [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States); Institute of Soil, Water and Environmental Science, Zhejiang University, Hangzhou 310029 (China); Ficklin, Darren [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States); Zhang Minghua [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States); Institute of Watershed Science and Environmental Ecology, Wenzhou Medical College, Wenzhou, 325000 (China)], E-mail: mhzhang@ucdavis.edu

    2008-12-15

    The hydrology, sediment, and pesticide transport components of the Soil and Water Assessment Tool (SWAT) were evaluated on the northern San Joaquin Valley watershed of California. The Nash-Sutcliffe coefficients for monthly stream flow and sediment load ranged from 0.49 to 0.99 over the watershed during the study period of 1992-2005. The calibrated SWAT model was applied to simulate fate and transport processes of two organophosphate pesticides of diazinon and chlorpyrifos at watershed scale. The model generated satisfactory predictions of dissolved pesticide loads relative to the monitoring data. The model also showed great success in capturing spatial patterns of dissolved diazinon and chlorpyrifos loads according to the soil properties and landscape morphology over the large agricultural watershed. This study indicated that curve number was the major factor influencing the hydrology while pesticide fate and transport were mainly affected by surface runoff and pesticide application and in the study area. - Major factors governing the instream loads of organophosphate pesticides are magnitude and timing of surface runoff and pesticide application.

  18. An in vitro simulation model to assess the severity of edge loading and wear, due to variations in component positioning in hip joint replacements.

    Science.gov (United States)

    O'Dwyer Lancaster-Jones, O; Williams, S; Jennings, L M; Thompson, J; Isaac, G H; Fisher, J; Al-Hajjar, M

    2017-09-23

    The aim of this study was to develop a preclinical in vitro method to predict the occurrence and severity of edge loading condition associated with the dynamic separation of the centres of the head and cup (in the absence of impingement) for variations in surgical positioning of the cup. Specifically, this study investigated the effect of both the variations in the medial-lateral translational mismatch between the centres of the femoral head and acetabular cup and the variations in the cup inclination angles on the occurrence and magnitude of the dynamic separation, the severity of edge loading, and the wear rate of ceramic-on-ceramic hip replacement bearings in a multi-station hip joint simulator during a walking gait cycle. An increased mismatch between the centres of rotation of the femoral head and acetabular cup resulted in an increased level of dynamic separation and an increase in the severity of edge loading condition which led to increased wear rate in ceramic-on-ceramic bearings. Additionally for a given translational mismatch, an increase in the cup inclination angle gave rise to increased dynamic separation, worst edge loading conditions, and increased wear. To reduce the occurrence and severity of edge loading, the relative positions (the mismatch) of the centres of rotation of the head and the cup should be considered alongside the rotational position of the acetabular cup. This study has considered the combination of mechanical and tribological factors for the first time in the medial-lateral axis only, involving one rotational angle (inclination) and one translational mismatch. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc.

  19. Surface Temperature Variation Prediction Model Using Real-Time Weather Forecasts

    Science.gov (United States)

    Karimi, M.; Vant-Hull, B.; Nazari, R.; Khanbilvardi, R.

    2015-12-01

    Combination of climate change and urbanization are heating up cities and putting the lives of millions of people in danger. More than half of the world's total population resides in cities and urban centers. Cities are experiencing urban Heat Island (UHI) effect. Hotter days are associated with serious health impacts, heart attaches and respiratory and cardiovascular diseases. Densely populated cities like Manhattan, New York can be affected by UHI impact much more than less populated cities. Even though many studies have been focused on the impact of UHI and temperature changes between urban and rural air temperature, not many look at the temperature variations within a city. These studies mostly use remote sensing data or typical measurements collected by local meteorological station networks. Local meteorological measurements only have local coverage and cannot be used to study the impact of UHI in a city and remote sensing data such as MODIS, LANDSAT and ASTER have with very low resolution which cannot be used for the purpose of this study. Therefore, predicting surface temperature in urban cities using weather data can be useful.Three months of Field campaign in Manhattan were used to measure spatial and temporal temperature variations within an urban setting by placing 10 fixed sensors deployed to measure temperature, relative humidity and sunlight. Fixed instrument shelters containing relative humidity, temperature and illumination sensors were mounted on lampposts in ten different locations in Manhattan (Vant-Hull et al, 2014). The shelters were fixed 3-4 meters above the ground for the period of three months from June 23 to September 20th of 2013 making measurements with the interval of 3 minutes. These high resolution temperature measurements and three months of weather data were used to predict temperature variability from weather forecasts. This study shows that the amplitude of spatial and temporal variation in temperature for each day can be predicted

  20. SIMULATION OF TEMPERATURE AND TRANSPORT LOAD IMPACT ON FORMATION AND DEVELOPMENT OF CRACKS ON ASPHALT-CONCRETE ROAD SURFACES

    OpenAIRE

    I. S. Melnikova

    2012-01-01

    An analysis of statistical data has shown that about 60 % of all types of road surface destructions and damages in the Republic of Belarus are attributed to cracks (separate, frequent and cracks network). The process of cracks formation in the asphalt concrete pavement is rather complicated and it is affected by a number of factors. The most important and determining factors are character and value of traffic loads, temperature action, road pavement structure, properties of materials used for...

  1. Frost behavior of a fin surface with temperature variation along heat exchanger fins

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Soo; Kim, Min Soo; Lee, Kwan Soo [Hanyang Univ., Seoul (Korea, Republic of); Kim, Ook Joong [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2007-07-01

    This paper presents a mathematical model for predicting the frost behavior formed on heat exchanger fins, considering fin heat conduction under frosting condition. The model is composed of air-side, the frost layer, and fin region, and they are coupled to the frost layer. The frost behavior is more accurately predicted with fin heat conduction considered (Case A) than with a constant fin surface temperature assumed (Case B). The results indicate that the frost thickness and heat transfer rate for Case B are over-predicted in most regions of the fin, as compared to those for Case A. Also, for Case A, the maximum frost thickness varies little with the fin length variations, and the extension of the fin length over 30 mm contributes insignificantly to heat transfer.

  2. Variational analysis for simulating free-surface flows in a porous medium

    Directory of Open Access Journals (Sweden)

    Shabbir Ahmed

    2003-01-01

    is used to obtain a discrete form of equations for a two-dimensional domain. The matrix characteristics and the stability criteria have been investigated to develop a stable numerical algorithm for solving the governing equation. A computer programme has been written to solve a symmetric positive definite system obtained from the variational finite element analysis. The system of equations is solved using the conjugate gradient method. The solution generates time-varying hydraulic heads in the subsurface. The interfacing free surface between the unsaturated and saturated zones in the variably saturated domain is located, based on the computed hydraulic heads. Example problems are investigated. The finite element solutions are compared with the exact solutions for the example problems. The numerical characteristics of the finite element solution method are also investigated using the example problems.

  3. Patterns of morphological variation in enamel-dentin junction and outer enamel surface of human molars.

    Science.gov (United States)

    Morita, Wataru; Yano, Wataru; Nagaoka, Tomohito; Abe, Mikiko; Ohshima, Hayato; Nakatsukasa, Masato

    2014-06-01

    Tooth crown patterning is governed by the growth and folding of the inner enamel epithelium (IEE) and the following enamel deposition forms outer enamel surface (OES). We hypothesized that overall dental crown shape and covariation structure are determined by processes that configurate shape at the enamel-dentine junction (EDJ), the developmental vestige of IEE. This this hypothesis was tested by comparing patterns of morphological variation between EDJ and OES in human permanent maxillary first molar (UM1) and deciduous second molar (um2). Using geometric morphometric methods, we described morphological variation and covariation between EDJ and OES, and evaluated the strength of two components of phenotypic variability, canalization and morphological integration, in addition to the relevant evolutionary flexibility, i.e. the ability to respond to selective pressure. The strength of covariation between EDJ and OES was greater in um2 than in UM1, and the way that multiple traits covary between EDJ and OES was different between these teeth. The variability analyses showed that EDJ had less shape variation and a higher level of morphological integration than OES, which indicated that canalization and morphological integration acted as developmental constraints. These tendencies were greater in UM1 than in um2. On the other hand, EDJ and OES had a comparable level of evolvability in these teeth. Amelogenesis could play a significant role in tooth shape and covariation structure, and its influence was not constant among teeth, which may be responsible for the differences in the rate and/or period of enamel formation. © 2014 Anatomical Society.

  4. Three-dimensional shape variation of talar surface morphology in hominoid primates.

    Science.gov (United States)

    Parr, W C H; Soligo, C; Smaers, J; Chatterjee, H J; Ruto, A; Cornish, L; Wroe, S

    2014-07-01

    The hominoid foot is of particular interest to biological anthropologists, as changes in its anatomy through time reflect the adoption of terrestrial locomotion, particularly in species of Australopithecus and Homo. Understanding the osteological morphology associated with changes in whole foot function and the development of the plantar medial longitudinal foot arch are key to understanding the transition through habitual bipedalism in australopithecines to obligate bipedalism and long-distance running in Homo. The talus is ideal for studying relationships between morphology and function in this context, as it is a major contributor to the adduction-abduction, plantar-dorsal flexion and inversion-eversion of the foot, and transmits all forces encountered from the foot to the leg. The talar surface is predominantly covered by articular facets, which have different quantifiable morphological characters, including surface area, surface curvature and orientation. The talus also presents challenges to the investigator, as its globular shape is very difficult to quantify accurately and reproducibly. Here we apply a three-dimensional approach using type 3 landmarks (slid semilandmarks) that are geometrically homologous to determine overall talar shape variations in a range of living and fossil hominoid taxa. Additionally, we use novel approaches to quantify the relative orientations and curvatures of talar articular facets by determining the principal vectors of facet orientation and fitting spheres to articular facets. The resulting metrics are analysed using phylogenetic regressions and principal components analyses. Our results suggest that articular surface curvatures reflect locomotor specialisations with, in particular, orangutans having more highly curved facets in all but the calcaneal facet. Similarly, our approach to quantifying articular facet orientation appears to be effective in discriminating between extant hominoid species, and may therefore provide a

  5. Interannual Variation of the Surface Temperature of Tropical Forests from Satellite Observations

    Directory of Open Access Journals (Sweden)

    Huilin Gao

    2016-01-01

    Full Text Available Land surface temperatures (LSTs within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I and the Special Sensor Microwave Imager Sounder (SSMIS, providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability of cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP reanalysis data.

  6. Seasonal variation in aragonite saturation in surface waters of Puget Sound – a pilot study

    Directory of Open Access Journals (Sweden)

    Gregory Pelletier

    2018-01-01

    Full Text Available A pilot study of sampling, using monthly marine flights over spatially distributed stations, was conducted with the aim to characterize the carbonate system in Puget Sound over a full year-long period. Surface waters of Puget Sound were found to be under-saturated with respect to aragonite during October–March, and super-saturated during April–September. Highest pCO2 and lowest pH occurred during the corrosive October–March period. Lowest pCO2 and highest pH occurred during the super-saturated April–September period. The monthly variations in pCO2 , pH, and aragonite saturation state closely followed the variations in monthly average chlorophyll a. Super-saturated conditions during April–September are likely strongly influenced by photosynthetic uptake of CO2 during the phytoplankton growing season. The relationship between phytoplankton production, the carbonate system, and aragonite saturation state suggests that long-term trends in eutrophication processes may contribute to trends in ocean acidification in Puget Sound

  7. Seasonal and spatial variations in rare earth elements and yttrium of dissolved load in the middle, lower reaches and estuary of the Minjiang River, southeastern China

    Science.gov (United States)

    Zhu, Xuxu; Gao, Aiguo; Lin, Jianjie; Jian, Xing; Yang, Yufeng; Zhang, Yanpo; Hou, Yuting; Gong, Songbai

    2017-09-01

    With the aim of elucidating the spatial and seasonal behaviors of rare earth elements (REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3-785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations (ΣREE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow (SHF), normal flow (NF), low flow (LF) and high flow (HF) season, respectively. The R (L/M) and R (H/M) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEs-enrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fluctuate and positively correlate to salinity in estuary, probably because of the geochemical

  8. Bone reactions adjacent to titanium implants with different surface characteristics subjected to static load. A study in the dog (II)

    DEFF Research Database (Denmark)

    Gotfredsen, K; Berglundh, T; Lindhe, J

    2001-01-01

    extracted bilaterally. 12 weeks later, 2 implants with a TPS surface were placed in one side and 2 implants with a machined surface were placed in the contralateral side. Twelve weeks after implant installation, crowns, connected in pairs with orthodontic expansion screws, were fitted to the implants......The purpose of the present study was to compare bone reactions adjacent to titanium implants with either a titanium plasma-sprayed (TPS) or a machined surface subjected to lateral static loading induced by an expansion force. In 3 labrador dogs, the 2nd, 3rd and 4th mandibular premolars were...... and histometric examination. A higher marginal bone level was observed around implants with a TPS surface compared to machined implants. Furthermore, the values describing the amount of bone-to-implant contact at the bone/implant interface as well as the density of the peri-implant bone were lower at the machined...

  9. Seasonal and latitudinal variations of surface fluxes at two Arctic terrestrial sites

    Science.gov (United States)

    Grachev, Andrey A.; Persson, P. Ola G.; Uttal, Taneil; Akish, Elena A.; Cox, Christopher J.; Morris, Sara M.; Fairall, Christopher W.; Stone, Robert S.; Lesins, Glen; Makshtas, Alexander P.; Repina, Irina A.

    2017-11-01

    This observational study compares seasonal variations of surface fluxes (turbulent, radiative, and soil heat) and other ancillary atmospheric/surface/permafrost data based on in-situ measurements made at terrestrial research observatories located near the coast of the Arctic Ocean. Hourly-averaged multiyear data sets collected at Eureka (Nunavut, Canada) and Tiksi (East Siberia, Russia) are analyzed in more detail to elucidate similarities and differences in the seasonal cycles at these two Arctic stations, which are situated at significantly different latitudes (80.0°N and 71.6°N, respectively). While significant gross similarities exist in the annual cycles of various meteorological parameters and fluxes, the differences in latitude, local topography, cloud cover, snowfall, and soil characteristics produce noticeable differences in fluxes and in the structures of the atmospheric boundary layer and upper soil temperature profiles. An important factor is that even though higher latitude sites (in this case Eureka) generally receive less annual incoming solar radiation but more total daily incoming solar radiation throughout the summer months than lower latitude sites (in this case Tiksi). This leads to a counter-intuitive state where the average active layer (or thaw line) is deeper and the topsoil temperature in midsummer are higher in Eureka which is located almost 10° north of Tiksi. The study further highlights the differences in the seasonal and latitudinal variations of the incoming shortwave and net radiation as well as the moderating cloudiness effects that lead to temporal and spatial differences in the structure of the atmospheric boundary layer and the uppermost ground layer. Specifically the warm season (Arctic summer) is shorter and mid-summer amplitude of the surface fluxes near solar noon is generally less in Eureka than in Tiksi. During the dark Polar night and cold seasons (Arctic winter) when the ground is covered with snow and air temperatures

  10. Variational assimilation of land surface temperature observations for enhanced river flow predictions

    Science.gov (United States)

    Ercolani, Giulia; Castelli, Fabio

    2016-04-01

    Data assimilation (DA) has the potential of improving hydrologic forecasts. However, many issues arise in case it is employed for spatially distributed hydrologic models that describes processes in various compartments: large dimensionality of the inverse problem, layers governed by different equations, non-linear and discontinuous model structure, complex topology of domains such as surface drainage and river network.On the other hand, integrated models offer the possibility of improving prediction of specific states by exploiting observations of quantities belonging to other compartments. In terms of forecasting river discharges, and hence for their enhancement, soil moisture is a key variable, since it determines the partitioning of rainfall into infiltration and surface runoff. However, soil moisture measurements are affected by issues that could prevent a successful DA and an actual improvement of discharge predictions.In-situ measurements suffer a dramatic spatial scarcity, while observations from satellite are barely accurate and provide spatial information only at a very coarse scale (around 40 km).Hydrologic models that explicitly represent land surface processes of coupled water and energy balance provide a valid alternative to direct DA of soil moisture.They gives the possibility of inferring soil moisture states through DA of remotely sensed Land Surface Temperature (LST), whose measurements are more accurate and with a higher spatial resolution in respect to those of soil moisture. In this work we present the assimilation of LST data in a hydrologic model (Mobidic) that is part of the operational forecasting chain for the Arno river, central Italy, with the aim of improving flood predictions. Mobidic is a raster based, continuous in time and distributed in space hydrologic model, with coupled mass and energy balance at the surface and coupled groundwater and surface hydrology. The variational approach is adopted for DA, since it requires less

  11. Estimation of Land Surface Fluxes and Their Uncertainty via Variational Data Assimilation Approach

    Science.gov (United States)

    Abdolghafoorian, A.; Farhadi, L.

    2016-12-01

    Accurate estimation of land surface heat and moisture fluxes as well as root zone soil moisture is crucial in various hydrological, meteorological, and agricultural applications. "In situ" measurements of these fluxes are costly and cannot be readily scaled to large areas relevant to weather and climate studies. Therefore, there is a need for techniques to make quantitative estimates of heat and moisture fluxes using land surface state variables. In this work, we applied a novel approach based on the variational data assimilation (VDA) methodology to estimate land surface fluxes and soil moisture profile from the land surface states. This study accounts for the strong linkage between terrestrial water and energy cycles by coupling the dual source energy balance equation with the water balance equation through the mass flux of evapotranspiration (ET). Heat diffusion and moisture diffusion into the column of soil are adjoined to the cost function as constraints. This coupling results in more accurate prediction of land surface heat and moisture fluxes and consequently soil moisture at multiple depths with high temporal frequency as required in many hydrological, environmental and agricultural applications. One of the key limitations of VDA technique is its tendency to be ill-posed, meaning that a continuum of possibilities exists for different parameters that produce essentially identical measurement-model misfit errors. On the other hand, the value of heat and moisture flux estimation to decision-making processes is limited if reasonable estimates of the corresponding uncertainty are not provided. In order to address these issues, in this research uncertainty analysis will be performed to estimate the uncertainty of retrieved fluxes and root zone soil moisture. The assimilation algorithm is tested with a series of experiments using a synthetic data set generated by the simultaneous heat and water (SHAW) model. We demonstrate the VDA performance by comparing the

  12. [Quantitative variations of osteocalcin in the culture media of bones subjected to intermittent mechanical loads in vitro].

    Science.gov (United States)

    Lozupone, E; Favia, A; Cafagna, B; Cantatore, F P

    1993-04-01

    A study has been carried out on the dynamics of the osteogenesis induced in vitro by an intermittent mechanical load applied on intact metatarsals isolated from 12 day-old rats. The metatarsals, as soon as isolated, were deprived of both the ends and placed in culture medium (BGJb enriched with 10% FCS, 65 micrograms of ascorbic acid, penicillin, strepto) without a mechanical load. After 4-5 hours, half the bones were placed in our device, described in our previous paper (2), and submitted to a daily cycle of an intermittent mechanical load (11.6 g/mm2) 1/2 h long, at 1 Hz frequency. The remaining bones, used as control, were cultured in the same medium, without any mechanical load. 24, 48 and 72 hours from the first application of the load the bones were fixed, embedded (decalcified or undecalcified) and serially sectioned. The sections were stained with toluidin blu and trichromic Masson-Goldner. On the perimeter of 5 non-consecutive sections of each bone the number of the osteoblasts at 250x, and the nuclear volume of the same cells at 1000x were evaluated. In the culture media the alcaline phosphatase activity (p-nitrophenol as substrate) and the concentration of osteocalcin (RIA) were measured. The number and nuclear volume of the osteoblasts are higher in the loaded than in the control bones (tab. 1). The alcaline phosphatase activity does not vary in the control bones between 24 and 72 h, while it increases in the loaded bones. The concentration of the osteocalcin shows a slight increase at 48 h in the control bones, and a significant decrease int he loaded bones (fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Loading an Optical Trap with Diamond Nanocrystals Containing Nitrogen-Vacancy Centers from a Surface

    Science.gov (United States)

    Hsu, Jen-Feng; Ji, Peng; Dutt, M. V. Gurudev; D'Urso, Brian R.

    2015-03-01

    We present a simple and effective method of loading particles into an optical trap. Our primary application of this method is loading photoluminescent material, such as diamond nanocrystals containing nitrogen-vacancy (NV) centers, for coupling the mechanical motion of the trapped crystal with the spin of the NV centers. Highly absorptive material at the trapping laser frequency, such as tartrazine dye, is used as media to attach nanodiamonds and burn into a cloud of air-borne particles as the material is swept near the trapping laser focus on a glass slide. Particles are then trapped with the laser used for burning or transferred to a second laser trap at a different wavelength. Evidence of successful loading diamond nanocrystals into the trap presented includes high sensitivity of the photoluminecscence (PL) to the excitation laser and the PL spectra of the optically trapped particles

  14. ArcNLET: A GIS-based software to simulate groundwater nitrate load from septic systems to surface water bodies

    Science.gov (United States)

    Rios, J. Fernando; Ye, Ming; Wang, Liying; Lee, Paul Z.; Davis, Hal; Hicks, Rick

    2013-03-01

    Onsite wastewater treatment systems (OWTS), or septic systems, can be a significant source of nitrates in groundwater and surface water. The adverse effects that nitrates have on human and environmental health have given rise to the need to estimate the actual or potential level of nitrate contamination. With the goal of reducing data collection and preparation costs, and decreasing the time required to produce an estimate compared to complex nitrate modeling tools, we developed the ArcGIS-based Nitrate Load Estimation Toolkit (ArcNLET) software. Leveraging the power of geographic information systems (GIS), ArcNLET is an easy-to-use software capable of simulating nitrate transport in groundwater and estimating long-term nitrate loads from groundwater to surface water bodies. Data requirements are reduced by using simplified models of groundwater flow and nitrate transport which consider nitrate attenuation mechanisms (subsurface dispersion and denitrification) as well as spatial variability in the hydraulic parameters and septic tank distribution. ArcNLET provides a spatial distribution of nitrate plumes from multiple septic systems and a load estimate to water bodies. ArcNLET's conceptual model is divided into three sub-models: a groundwater flow model, a nitrate transport and fate model, and a load estimation model which are implemented as an extension to ArcGIS. The groundwater flow model uses a map of topography in order to generate a steady-state approximation of the water table. In a validation study, this approximation was found to correlate well with a water table produced by a calibrated numerical model although it was found that the degree to which the water table resembles the topography can vary greatly across the modeling domain. The transport model uses a semi-analytical solution to estimate the distribution of nitrate within groundwater, which is then used to estimate a nitrate load using a mass balance argument. The estimates given by ArcNLET are

  15. Optical Feather and Foil for Shape and Dynamic Load Sensing of Critical Flight Surfaces, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Future flight vehicles may comprise complex flight surfaces requiring coordinated in-situ sensing and actuation. Inspired by the complexity of the flight surfaces on...

  16. Extravascular Lung Water Does Not Increase in Hypovolemic Patients after a Fluid-Loading Protocol Guided by the Stroke Volume Variation

    Directory of Open Access Journals (Sweden)

    Carlos Ferrando

    2012-01-01

    Full Text Available Introduction. Circulatory failure secondary to hypovolemia is a common situation in critical care patients. Volume replacement is the first option for the treatment of hypovolemia. A possible complication of volume loading is pulmonary edema, quantified at the bedside by the measurement of extravascular lung water index (ELWI. ELWI predicts progression to acute lung injury (ALI in patients with risk factors for developing it. The aim of this study was to assess whether fluid loading guided by the stroke volume variation (SVV, in patients presumed to be hypovolemic, increased ELWI or not. Methods. Prospective study of 17 consecutive postoperative, fully mechanically ventilated patients diagnosed with circulatory failure secondary to presumed hypovolemia were included. Cardiac index (CI, ELWI, SVV, and global end-diastolic volume index (GEDI were determined using the transpulmonary thermodilution technique during the first 12 hours after fluid loading. Volume replacement was done with a strict hemodynamic protocol. Results. Fluid loading produced a significant increase in CI and a decrease in SVV. ELWI did not increase. No correlation was found between the amount of fluids administered and the change in ELWI. Conclusion. Fluid loading guided by SVV in hypovolemic and fully mechanically ventilated patients in sinus rhythm does not increase ELWI.

  17. Multilayer Coating of Tetrandrine-loaded PLGA nanoparticles: Effect of surface charges on cellular uptake rate and drug release profile.

    Science.gov (United States)

    Meng, Rui; Li, Ke; Chen, Zhe; Shi, Chen

    2016-02-01

    The effect of surface charges on the cellular uptake rate and drug release profile of tetrandrine-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPNs) was studied. Stabilizer-free nanoprecipitation method was used in this study for the synthesis of TPNs. A typical layer-by-layer approach was applied for multi-coating particles' surface with use of poly(styrene sulfonate) sodium salt (PSS) as anionic layer and poly(allylamine hydrochloride) (PAH) as cationic layer. The modified TPNs were characterized by different physicochemical techniques such as Zeta sizer, scanning electron microscopy and transmission electron microscopy. The drug loading efficiency, release profile and cellular uptake rate were evaluated by high performance liquid chromatography and confocal laser scanning microscopy, respectively. The resultant PSS/PAH/PSS/PAH/TPNs (4 layers) exhibited spherical-shaped morphology with the average size of 160.3±5.165 nm and zeta potential of-57.8 mV. The encapsulation efficiency and drug loading efficiency were 57.88% and 1.73%, respectively. Multi-layer coating of polymeric materials with different charges on particles' surface could dramatically influence the drug release profile of TPNs (4 layers vs. 3 layers). In addition, variable layers of surface coating could also greatly affect the cellular uptake rate of TPNs in A549 cells within 8 h. Overall, by coating particles' surface with those different charged polymers, precise control of drug release as well as cellular uptake rate can be achieved simultaneously. Thus, this approach provides a new strategy for controllable drug delivery.

  18. Effect of cold plasma pre-treatment on photocatalytic activity of 3D fabric loaded with nano-photocatalysts: Response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Ghoreishian, Seyed Majid, E-mail: m.ghoreishian.1985@gmail.com [Young Researchers and Elite Club, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Badii, Khashayar [Department of Environmental Researches, Institute for Color Science and Technology (ICST), Tehran (Iran, Islamic Republic of); Norouzi, Mohammad [Graduate Program of Biomedical Engineering, University of Manitoba, Winnipeg, MB (Canada); Malek, Kaveh [Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-03-01

    Graphical abstract: - Highlights: • The potential of immobilized TiO{sub 2} and ZnO nanophotocatalysts for the removal of reactive dye was investigated. • Optimum decolorization conditions have been determined. • The immobilized nanophotocatalysts decolorized azo dyes completely from a textile effluent within 60 min. • Photocatalytic decolorization rates obeyed the pseudo-first-order rate. - Abstract: In this study, the physico-chemical effects occasioned by the cold plasma discharge (CPD) on the photo-decolorization of Reactive Orange 16 (RO16) by 3D fabrics (spacer fabrics) loaded with ZnO:TiO{sub 2} nano-photocatalysts (nphs) were optimized via response surface methodology (RSM). CPD was employed to improve the surface characteristics of the spacer fabrics for nphs loading. Surface morphology and color variation were studied utilizing scanning electron microscopy (SEM) and CIE-Lab system, respectively. The effect of CPD on the wetting ability of the spacer fabrics was examined using dynamic adsorption measurement (DAM). Also, X-ray fluorescence (XRF) was utilized to investigate the durability of the nphs on the spacer fabrics. All the experiments were implemented in a Box–Behnken design (BBD) with three independent variables (CPD treatment time, dye concentration and irradiation time) in order to optimize the decolorization of RO16. The anticipated values of the decolorization efficiency were found to be in excellent agreement with the experimental values (R{sup 2} = 0.9996, Adjusted R{sup 2} = 0.9992). The kinetic analysis demonstrated that the photocatalytic decolorization followed the Langmuir–Hinshelwood kinetic model. In conclusion, this heterogeneous photocatalytic process is capable of decolorizing and mineralizing azoic reactive dye in textile wastewater. Moreover, the results confirmed that RSM based on the BBD was a suitable method to optimize the operating conditions of RO16 degradation.

  19. Recent Successes and Remaining Challenges in Predicting Phosphorus Loading to Surface Waters at Large Scales

    Science.gov (United States)

    Harrison, J.; Metson, G.; Beusen, A.

    2017-12-01

    Over the past century humans have greatly accelerated phosphorus (P) flows from land to aquatic ecosystems, causing eutrophication and associated effects such as harmful algal blooms and hypoxia. Effectively addressing this challenge requires understanding geographic and temporal distribution of aquatic P loading, knowledge of major controls on P loading, and the relative importance of various potential P sources. The Global (N)utrient (E)xport from (W)ater(S)heds) NEWS model and recent improvements and extensions of this modeling system can be used to generate this understanding. This presentation will focus on insights global NEWS models grant into past, present, and potential future P sources and sinks, with a focus on the world's large rivers. Early results suggest: 1) that while aquatic P loading is globally dominated by particulate forms, dissolved P can be locally dominant; 2) that P loading has increased substantially at the global scale, but unevenly between world regions, with hotspots in South and East Asia; 3) that P loading is likely to continue to increase globally, but decrease in certain regions that are actively pursuing proactive P management; and 4) that point sources, especially in urban centers, play an important (even dominant) role in determining loads of dissolved inorganic P. Despite these insights, substantial unexplained variance remains when model predictions and measurements are compared at global and regional scales, for example within the U.S. Disagreements between model predictions and measurements suggest opportunities for model improvement. In particular, explicit inclusion of soil characteristics and the concept of temporal P legacies in future iterations of NEWS (and other) models may help improve correspondence between models and measurements.

  20. Influence of surface treatment and cyclic loading on the durability of repaired all-ceramic crowns

    Directory of Open Access Journals (Sweden)

    Ahmed Attia

    2010-04-01

    Full Text Available OBJECTIVE: This study investigated the durability of repaired all-ceramic crowns after cyclic loading. MATERIAL AND METHODS: Eighty In-ceram zirconia crowns were fabricated to restore prepared maxillary premolars. Resin cement was used for cementation of crowns. Palatal cusps were removed to simulate fracture of veneering porcelain and divided into 4 groups (n = 20. Fracture site was treated before repair as follows: roughening with diamond bur, (DB; air abrasion using 50 µm Al2O3, (AA and silica coating using Cojet system followed by silane application, (SC. Control group (CG 20 specimens were left without fracture. Palatal cusps were repaired using composite resin. Specimens were stored in water bath at 37ºC for one week. Ten specimens of each group were subjected to cyclic loading. Fracture load (N was recorded for each specimen using a universal testing machine. Two-way analysis of variance (ANOVA and Tukey honestly significant difference (HSD test (a=.05 were used for statistical analysis. RESULTS: There was statistically significant difference between control and tested groups, (p<0.001. Post Hoc analysis with the Tukey HSD test showed that cyclic loading fatigue significantly decreased means fracture load of control and test groups as follows (CG, 950.4±62.6 / 872.3±87.4, P = 0.0004, (DB, 624.2 ±38 / 425.5± 31.7, P <.001, (AA, 711.5 ±15.5 / 490 ± 25.2, p <0.001 and (SC, 788.7 ± 18.1 / 610.2 ± 25.2, P <.001, while silica coating and silane application significantly increased fracture load of repaired crowns (p<0.05. CONCLUSION: Repair of fractured In-ceram zirconia crowns after chairside treatment of the fracture site by silica coating and silane application could improve longevity of repaired In-ceram zirconia crowns.

  1. Temporal aspects of surface water quality variation using robust statistical tools.

    Science.gov (United States)

    Mustapha, Adamu; Aris, Ahmad Zaharin; Ramli, Mohammad Firuz; Juahir, Hafizan

    2012-01-01

    Robust statistical tools were applied on the water quality datasets with the aim of determining the most significance parameters and their contribution towards temporal water quality variation. Surface water samples were collected from four different sampling points during dry and wet seasons and analyzed for their physicochemical constituents. Discriminant analysis (DA) provided better results with great discriminatory ability by using five parameters with (P < 0.05) for dry season affording more than 96% correct assignation and used five and six parameters for forward and backward stepwise in wet season data with P-value (P < 0.05) affording 68.20% and 82%, respectively. Partial correlation results revealed that there are strong (r(p) = 0.829) and moderate (r(p) = 0.614) relationships between five-day biochemical oxygen demand (BOD(5)) and chemical oxygen demand (COD), total solids (TS) and dissolved solids (DS) controlling for the linear effect of nitrogen in the form of ammonia (NH(3)) and conductivity for dry and wet seasons, respectively. Multiple linear regression identified the contribution of each variable with significant values r = 0.988, R(2) = 0.976 and r = 0.970, R(2) = 0.942 (P < 0.05) for dry and wet seasons, respectively. Repeated measure t-test confirmed that the surface water quality varies significantly between the seasons with significant value P < 0.05.

  2. Temporal Aspects of Surface Water Quality Variation Using Robust Statistical Tools

    Directory of Open Access Journals (Sweden)

    Adamu Mustapha

    2012-01-01

    Full Text Available Robust statistical tools were applied on the water quality datasets with the aim of determining the most significance parameters and their contribution towards temporal water quality variation. Surface water samples were collected from four different sampling points during dry and wet seasons and analyzed for their physicochemical constituents. Discriminant analysis (DA provided better results with great discriminatory ability by using five parameters with (P<0.05 for dry season affording more than 96% correct assignation and used five and six parameters for forward and backward stepwise in wet season data with P-value (P<0.05 affording 68.20% and 82%, respectively. Partial correlation results revealed that there are strong (rp=0.829 and moderate (rp=0.614 relationships between five-day biochemical oxygen demand (BOD5 and chemical oxygen demand (COD, total solids (TS and dissolved solids (DS controlling for the linear effect of nitrogen in the form of ammonia (NH3 and conductivity for dry and wet seasons, respectively. Multiple linear regression identified the contribution of each variable with significant values r = 0.988, R2 = 0.976 and r = 0.970, R2 = 0.942 (P<0.05 for dry and wet seasons, respectively. Repeated measure t-test confirmed that the surface water quality varies significantly between the seasons with significant value P<0.05.

  3. Mobile load simulators - A tool to distinguish between the emissions due to abrasion and resuspension of PM10 from road surfaces

    Science.gov (United States)

    Gehrig, R.; Zeyer, K.; Bukowiecki, N.; Lienemann, P.; Poulikakos, L. D.; Furger, M.; Buchmann, B.

    2010-12-01

    Mechanically produced abrasion particles and resuspension processes are responsible for a significant part of the PM10 emissions of road traffic. However, specific differentiation between PM10 emissions due to abrasion and resuspension from road pavement is very difficult due to their similar elemental composition and highly correlated variation in time. In this work Mobile Load Simulators were used to estimate PM10 emission factors for pavement abrasion and resuspension on different pavement types for light and heavy duty vehicles. From the experiments it was derived that particle emissions due to abrasion from pavements in good condition are quite low in the range of only a few mg·km -1 per vehicle if quantifiable at all. Considerable abrasion emissions, however, can occur from damaged pavements. Resuspension of deposited dust can cause high and extremely variable particle emissions depending strongly on the dirt load of the road surface. Porous pavements seem to retain deposited dust better than dense pavements, thus leading to lower emissions due to resuspension compared to pavements with a dense structure (e.g. asphalt concrete). Tyre wear seemed not to be a quantitatively significant source of PM10 emissions from road traffic.

  4. Partitioning Evapotranspiration in Semiarid Grassland and Shrubland Ecosystems Using Diurnal Surface Temperature Variation

    Science.gov (United States)

    Moran, M. Susan; Scott, Russell L.; Keefer, Timothy O.; Paige, Ginger B.; Emmerich, William E.; Cosh, Michael H.; O'Neill, Peggy E.

    2007-01-01

    The encroachment of woody plants in grasslands across the Western U.S. will affect soil water availability by altering the contributions of evaporation (E) and transpiration (T) to total evapotranspiration (ET). To study this phenomenon, a network of flux stations is in place to measure ET in grass- and shrub-dominated ecosystems throughout the Western U.S. A method is described and tested here to partition the daily measurements of ET into E and T based on diurnal surface temperature variations of the soil and standard energy balance theory. The difference between the mid-afternoon and pre-dawn soil surface temperature, termed Apparent Thermal Inertia (I(sub A)), was used to identify days when E was negligible, and thus, ET=T. For other days, a three-step procedure based on energy balance equations was used to estimate Qe contributions of daily E and T to total daily ET. The method was tested at Walnut Gulch Experimental Watershed in southeast Arizona based on Bowen ratio estimates of ET and continuous measurements of surface temperature with an infrared thermometer (IRT) from 2004- 2005, and a second dataset of Bowen ratio, IRT and stem-flow gage measurements in 2003. Results showed that reasonable estimates of daily T were obtained for a multi-year period with ease of operation and minimal cost. With known season-long daily T, E and ET, it is possible to determine the soil water availability associated with grass- and shrub-dominated sites and better understand the hydrologic impact of regional woody plant encroachment.

  5. Melittin-loaded immunoliposomes against viral surface proteins, a new approach to antiviral therapy

    NARCIS (Netherlands)

    Falco Gracia, J.A.; Barrajon-Catalan, E.; Menendez-Gutierrez, M.P.; Coll, J.; Micol, V.; Estepa, A.

    2013-01-01

    In this study, melittin, a well-characterized pore-forming lytic amphiphilic peptide susceptible to be vehiculized in lipid membranes, has been utilized to study their antiviral properties. For this purpose, an assay based on melittin loaded-immunoliposomes previously described by our group was

  6. Influence of surface morphology and microstructure on performance of CVD tungsten coating under fusion transient thermal loads

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Youyun, E-mail: lianyy@swip.ac.cn [Southwestern Institute of Physics, Chengdu (China); Liu, Xiang; Wang, Jianbao; Feng, Fan [Southwestern Institute of Physics, Chengdu (China); Lv, Yanwei; Song, Jiupeng [China National R& D Center for Tungsten Technology, Xiamen Tungsten Co. Ltd, 361026 Xiamen (China); Chen, Jiming [Southwestern Institute of Physics, Chengdu (China)

    2016-12-30

    Highlights: • Thick CVD-W coatingswere deposited at a rapid growth rate. • The polished CVD-W coatings have highly textured structure and exhibited a very strong preferred orientation. • The polished CVD tungsten coatings show superior thermal shock resistance as compared with that of the as-deposited coatings. • The crack formation of the polished CVD-W was almost suppressed at an elevated temperature. - Abstract: Thick tungsten coatings have been deposited by chemical vapor deposition (CVD) at a rapid growth rate. A series of tungsten coatings with different thickness and surface morphology were prepared. The surface morphology, microstructure and preferred orientation of the CVD tungsten coatings were investigated. Thermal shock analyses were performed by using an electron beam facility to study the influence of the surface morphology and the microstructure on the thermal shock resistance of the CVD tungsten coatings. Repetitive (100 pulses) ELMs-like thermal shock loads were applied at various temperatures between room temperature and 600 °C with pulse duration of 1 ms and an absorbed power density of up to 1 GW/m{sup 2}. The results of the tests demonstrated that the specific surface morphology and columnar crystal structure of the CVD tungsten have significant influence on the surface cracking threshold and crack propagation of the materials. The CVD tungsten coatings with a polished surface show superior thermal shock resistance as compared with that of the as-deposited coatings with a rough surface.

  7. Novel curcumin-loaded human serum albumin nanoparticles surface functionalized with folate: characterization and in vitro/vivo evaluation.

    Science.gov (United States)

    Song, Zhiwang; Lu, Yonglin; Zhang, Xia; Wang, Haiping; Han, Junyi; Dong, Chunyan

    2016-01-01

    Folate-conjugated, curcumin-loaded human serum albumin nanoparticles (F-CM-HSANPs) were obtained by the chemical conjugation of folate to the surface of the curcumin (CM)-loaded human serum albumin nanoparticles (NPs). The NPs were characterized by various parameters, including size, polydispersity, zeta potential, morphology, encapsulation efficiency, and drug release profile. The mean particle size of F-CM-HSANPs was 165.6±15.7 nm (polydispersity index <0.28), and the average encapsulation efficiency percentage and drug loading percentage of the F-CM-HSANPs were 88.7%±4.8% and 7.9%±0.4%, respectively. Applied in vitro, the CM NPs, after conjugation with folate, maintained sustained release, and a faster release of CM was more visibly observed than the unconjugated NPs. F-CM-HSANPs can prolong the retention time of CM significantly in vivo. However, after intravenous injection of F-CM-HSANPs, the pharmacokinetic parameters of CM were not significantly different from those of CM-loaded human serum albumin NPs. The improved antitumor activity of F-CM-HSANPs may be attributable to the protection of drug from enzymatic deactivation followed by the selective localization at the desired site. These results suggest that the intravenous injection of F-CM-HSANPs is likely to have an advantage in the current clinical CM formulation, because it does not require the use of a solubilization agent and it is better able to target the tumor tissue.

  8. Electrostatic potential variation on the flux surface and its impact on impurity transport

    Science.gov (United States)

    García-Regaña, J. M.; Beidler, C. D.; Kleiber, R.; Helander, P.; Mollén, A.; Alonso, J. A.; Landreman, M.; Maaßberg, H.; Smith, H. M.; Turkin, Y.; Velasco, J. L.

    2017-05-01

    The impurity transport in magnetically confined plasmas under some conditions finds neither quantitatively nor qualitatively a satisfactory theory-based explanation. This compromises the successful realization of thermo-nuclear fusion for energy production since impurity accumulation is known to be one of the causes that limits the plasma performance through radiative losses and plasma dilution. Under stellarator reactor-relevant conditions, accumulation is supported by the negative (inwards pointing) radial electric field which must arise to satisfy the ambipolarity constraint on the neoclassical particle fluxes. The high charge number of the impurities makes their transport particularly sensitive to the presence of electric fields and, consequently, the electrostatic potential variation on the flux surface, {Φ1} , which conventional neoclassical theory usually neglects, may contribute to the theoretical interpretation of experimental results not yet fully understood, e.g. Ida et al (2009 Phys. Plasmas 16 056111) and Yoshinuma et al (2009 Nucl. Fusion 49 062002). In the present work we have considered different stellarator configurations and assessed the impact that {Φ1} has on the radial particle transport of selected impurities. The results for LHD show that {Φ1} can strongly modify this transport, resulting in large deviations of the level of inward impurity flux predicted by the standard neoclassical theory in most cases. In Wendelstein 7-X, on the contrary, {Φ1} is significantly smaller and, for the parameters considered, its effect only appreciable for impurities with high charge number. Finally, in TJ-II the potential variation leads to appreciable changes of the impurity radial flux, although not to the extent its large amplitude might lead one to think. The dependence on the chosen parameters and open questions for future developments are discussed.

  9. Separation of density and viscosity influence on liquid-loaded surface acoustic wave devices

    Science.gov (United States)

    Herrmann, F.; Hahn, D.; Büttgenbach, S.

    1999-05-01

    Love-mode sensors are reported for separate measurement of liquid density and viscosity. They combine the general merits of Love-mode devices, e.g., ease of sensitivity adjustment and robustness, with a highly effective procedure of separate determination of liquid density and viscosity. A model is proposed to describe the frequency response of the devices to liquid loading. Moreover, design rules are given for further optimization and sensitivity enhancement.

  10. Influence of surface treatment and cyclic loading on the durability of repaired all-ceramic crowns

    Science.gov (United States)

    ATTIA, Ahmed

    2010-01-01

    Objective This study investigated the durability of repaired all-ceramic crowns after cyclic loading. Material and methods Eighty In-ceram zirconia crowns were fabricated to restore prepared maxillary premolars. Resin cement was used for cementation of crowns. Palatal cusps were removed to simulate fracture of veneering porcelain and divided into 4 groups (n = 20). Fracture site was treated before repair as follows: roughening with diamond bur, (DB); air abrasion using 50 µm Al2O3, (AA) and silica coating using Cojet system followed by silane application, (SC). Control group (CG) 20 specimens were left without fracture. Palatal cusps were repaired using composite resin. Specimens were stored in water bath at 37°C for one week. Ten specimens of each group were subjected to cyclic loading. Fracture load (N) was recorded for each specimen using a universal testing machine. Two-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) test (α=.05) were used for statistical analysis. Results There was statistically significant difference between control and tested groups, (pcrowns (pzirconia crowns after chairside treatment of the fracture site by silica coating and silane application could improve longevity of repaired In-ceram zirconia crowns. PMID:20485932

  11. Contribution of Heavy Metal Leaching from Agricultural Soils to Surface Water Loads

    NARCIS (Netherlands)

    Bonten, L.T.C.; Romkens, P.F.A.M.; Brus, D.J.

    2008-01-01

    Point sources for surface water contamination have been reduced by 50 to 90% during the past decades in The Netherlands. However, quality guidelines for heavy metals are still exceeded in many surface waters. It has been suggested that leaching of heavy metals from (diffusively polluted) soils can

  12. Surface biomimetic modification with laminin-loaded heparin/poly-L-lysine nanoparticles for improving the biocompatibility

    International Nuclear Information System (INIS)

    Liu, Tao; Hu, Youdong; Tan, Jianying; Liu, Shihui; Chen, Junying; Guo, Xin; Pan, Changjiang; Li, Xia

    2017-01-01

    Late thrombus and restenosis caused by delayed endothelialization and insufficient biocompatibility of polymer coating continue to be the greatest limitations of drug-eluting stents. In this study, based on the specific structure of vascular basement membrane, a novel biomimetic nano-coating was constructed by incorporating laminin into electrostatic-assembled heparin/poly-L-lysine nanoparticles. Alteration of heparin and poly-L-lysine concentration ratio in a certain range has no significantly influence nanoparticle size, uniformity and stability, but may affect the chemical property and subsequently the binding efficiency to dopamine-coated titanium surface. By use of this feature, four different nanoparticles were synthesized and immobilized on titanium surface for creating gradient nanoparticle binding density. According to in vitro biocompatibility evaluation, the nanoparticle modified surfaces were found to effectively block coagulation pathway and reduce thrombosis formation. Moreover, NP10L and NP15L modified surface with relatively low heparin exposing density (4.9 to 7.1 μg/cm2) showed beneficial effect in selective promoting EPCs and ECs proliferation, as well as stimulating cell migration and NO synthesis. - Highlights: • A novel laminin-loaded anticoagulant nanoparticle was prepared and used for titanium surface modification. • The nanoparticle binding density was adjustable by alteration the concentration ratio of heparin and poly-L-lysine. • In a certain range of NPs density, the surface was found to selectively direct platelet and vascular cells behavior.

  13. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms

    Science.gov (United States)

    Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals ( P winter season in the coastal areas of Zazulwana and Honeydale ( P coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

  14. Modeling of Oblique Penetration into Geologic Targets Using Cavity Expansion Penetrator Loading with Target free-Surface Effects

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joe; Longcope, Donald B.; Tabbara, Mazen R.

    1999-06-01

    A procedure has been developed to represent the loading on a penetrator and its motion during oblique penetration into geologic media. The penetrator is modeled with the explicit dynamics, finite element computer program PRONTO 3D and the coupled pressure on the penetrator is given in a new loading option based on a separate cavity expansion (CE) solution that accounts for the pressure reduction from a nearby target free surface. The free-surface influence distance is selected in a predictive manner by considering the pressure to expand a spherical cavity in a finite radius sphere of the target material. The CE/PRONTO 3D procedure allows a detailed description of the penetrator for predicting shock environments or structural failure during the entire penetra- tion event and is sufficiently rapid to be used in design optimization. It has been evaluated by comparing its results with data from two field tests of a full-scale penetrator into frozen soil at an impact angles of 49.6 and 52.5 degrees from the horizontal. The measured penetrator rotations were 24 and 22 degrees, respectively. In the simulation, the rotation was 21 degrees and predom- inately resulted from the pressure reduction of the free surface. Good agreement was also found for the penetration depth and axial and lateral acceleration at two locations in the penetrator.

  15. Modeling of Oblique Penetration into Geologic Targets Using Cavity Expansion Penetrator Loading with Target free-Surface Effects

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joe; Longcope, Donald B.; Tabbara, Mazen R.

    1999-05-03

    A procedure has been developed to represent the loading on a penetrator and its motion during oblique penetration into geologic media. The penetrator is modeled with the explicit dynamics, finite element computer program PRONTO 3D and the coupled pressure on the penetrator is given in a new loading option based on a separate cavity expansion (CE) solution that accounts for the pressure-reduction from a nearby target free surface. The free-surface influ- ence distance is selected in a predictive manner by considering the pressure to expand a spherical cavity in a finite radius sphere of the target material. The CE/PRONTO 3D procedure allows a detailed description of the penetrator for predicting shock environments or structural failure dur- ing the entire penetration event and is sufficiently rapid to be used in design optimization. It has been evaluated by comparing its results with data from two field tests of a full-scale penetrator into frozen soil at an impact angles of 49.6 and 52.5 degrees from the horizontal. The measured penetrator rotations were 24 and 22 degrees, respectively. In the simulation, the rotation was21 degrees and predominately resulted from the pressure reduction of the free surface. Good agree- ment was also found for the penetration depth and axial and lateral acceleration at two locations in the penetrator.

  16. Seasonal and spatial variations of PPCP occurrence, removal and mass loading in three wastewater treatment plants located in different urbanization areas in Xiamen, China.

    Science.gov (United States)

    Sun, Qian; Li, Mingyue; Ma, Cong; Chen, Xiangqiang; Xie, Xiaoqing; Yu, Chang-Ping

    2016-01-01

    The occurrence and fate of 48 pharmaceuticals and personal care products (PPCPs) in three wastewater treatment plants (WWTPs) located in different urbanization areas in Xiamen, China was investigated over one year. Results showed that PPCPs were widely detected, but the major PPCPs in the influent, effluent, and sludge were different. Spatial and seasonal variations of PPCP levels in the influent and sludge were observed. The removal efficiencies for most PPCPs were similar among the three WWTPs, although they employed different biological treatment processes. Furthermore, the mass loadings per inhabitant of most pharmaceuticals had a positive correlation with the urbanization levels, indicating that most pharmaceutical usage was higher in the urban core compared to the suburban zones. The total mass loadings of all the 48 PPCPs in the effluent and waste sludge showed close proportions, which suggested the importance of proper waste sludge disposal to prevent a large quantity of PPCPs from entering the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Temporal variation of coastal surface sediment bacterial communities along an environmental pollution gradient.

    Science.gov (United States)

    Thiyagarajan, V; Tsoi, M M Y; Zhang, W; Qian, P Y

    2010-07-01

    Terminal restriction fragment length polymorphism analysis (T-RFLP) was used to track the changes of bacterial community compositions (BCC) in coastal surface sediments along an environmental pollution gradient between 2004 and 2006. BCC in the chronically contaminated sites showed the largest deviation from those in the adjacent sites. Surprisingly, BCC at two contrasting environments (oceanic vs. river-influenced) were more similar. Unexpectedly, the BCC did not recover (when compared to oceanic control site) even after 5 years of pollution abatement initiatives in Victoria Harbour, Hong Kong. On the other hand, disposal of treated sewage for 5 years in one of the sites did not significantly affect the BCC. A striking seasonal variation in the BCC was observed at only the polluted sites. Although factors other than pollution gradients may explain the observed BCC patterns, the information presented here can be useful in predicting long-term effects of pollution on BCC. Furthermore, this study suggests that BCC analysis using T-RFLP is a faster, reliable and easier approach to monitor microbenthic community response to environmental pollution gradient in coastal sediments. 2010 Elsevier Ltd. All rights reserved.

  18. Diffusion Filters for Variational Data Assimilation of Sea Surface Temperature in an Intermediate Climate Model

    Directory of Open Access Journals (Sweden)

    Xuefeng Zhang

    2015-01-01

    Full Text Available Sequential, adaptive, and gradient diffusion filters are implemented into spatial multiscale three-dimensional variational data assimilation (3DVAR as alternative schemes to model background error covariance matrix for the commonly used correction scale method, recursive filter method, and sequential 3DVAR. The gradient diffusion filter (GDF is verified by a two-dimensional sea surface temperature (SST assimilation experiment. Compared to the existing DF, the new GDF scheme shows a superior performance in the assimilation experiment due to its success in extracting the spatial multiscale information. The GDF can retrieve successfully the longwave information over the whole analysis domain and the shortwave information over data-dense regions. After that, a perfect twin data assimilation experiment framework is designed to study the effect of the GDF on the state estimation based on an intermediate coupled model. In this framework, the assimilation model is subject to “biased” initial fields from the “truth” model. While the GDF reduces the model bias in general, it can enhance the accuracy of the state estimation in the region that the observations are removed, especially in the South Ocean. In addition, the higher forecast skill can be obtained through the better initial state fields produced by the GDF.

  19. The effect of a low glycemic load diet on acne vulgaris and the fatty acid composition of skin surface triglycerides.

    Science.gov (United States)

    Smith, Robyn N; Braue, Anna; Varigos, George A; Mann, Neil J

    2008-04-01

    Dietary factors have long been implicated in acne pathogenesis. It has recently been hypothesized that low glycemic load diets may influence sebum production based on the beneficial endocrine effects of these diets. To determine the effect of a low glycemic load diet on acne and the fatty acid composition of skin surface triglycerides. Thirty-one male acne patients (aged 15-25 years) completed sebum sampling tests as part of a larger 12-week, parallel design dietary intervention trial. The experimental treatment was a low glycemic load diet, comprised of 25% energy from protein and 45% from low glycemic index carbohydrates. In contrast, the control situation emphasized carbohydrate-dense foods without reference to the glycemic index. Acne lesion counts were assessed during monthly visits. At baseline and 12-weeks, the follicular sebum outflow and composition of skin surface triglycerides were assessed using lipid absorbent tapes. At 12 weeks, subjects on the experimental diet demonstrated increases in the ratio of saturated to monounsaturated fatty acids of skin surface triglycerides when compared to controls [5.3+/-2.0% (mean+/-S.E.M.) vs. -2.7+/-1.7%, P=0.007]. The increase in the saturated/monounsaturated ratio correlated with acne lesion counts(r=-0.39, P=0.03). Increased follicular sebum outflow was also associated with an increase in the proportion of monounsaturated fatty acids in sebum (r=0.49, P=0.006). This suggests a possible role of desaturase enzymes in sebaceous lipogenesis and the clinical manifestation of acne. However, further work is needed to clarify the underlying role of diet in sebum gland physiology.

  20. Arctic and Antarctic diurnal and seasonal variations of snow albedo from multiyear Baseline Surface Radiation Network measurements

    OpenAIRE

    Wang, Xianwei; Zender, Charles S

    2011-01-01

    This study analyzes diurnal and seasonal variations of snow albedo at four Baseline Surface Radiation Network stations in the Arctic and Antarctica from 2003 to 2008 to elucidate similarities and differences in snow albedo diurnal cycles across geographic zones and to assess how diurnal changes in snow albedo affect the surface energy budget. At the seasonal scale, the daily albedo for the perennial snow at stations South Pole and Georg von Neumayer in Antarctica has a similar symmetric varia...

  1. Immediate and early loading of Straumann implants with a chemically modified surface (SLActive) in the posterior mandible and maxilla: 1-year results from a prospective multicenter study

    NARCIS (Netherlands)

    Ganeles, J.; Zollner, A.; Jackowski, J.; ten Bruggenkate, C.M.; Beagle, J.; Guerra, F.

    2008-01-01

    Objective: Immediate and early loading of implants can simplify treatment and increase patient satisfaction. This 3-year randomized-controlled trial will therefore evaluate survival rates and bone-level changes with immediately and early loaded Straumann implants with the SLActive surface. Material

  2. Preparation and characterization of gadolinium-loaded PLGA particles surface modified with RGDS for the detection of thrombus

    Directory of Open Access Journals (Sweden)

    Zhang Y

    2013-10-01

    Full Text Available Yu Zhang,1 Jun Zhou,1 Dajing Guo,1 Meng Ao,2 Yuanyi Zheng,2 Zhigang Wang21Department of Radiology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 2Institute of Ultrasound Imaging, Department of Ultrasound, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of ChinaAbstract: Thrombotic disease is a leading cause of death and disability worldwide. The development of magnetic resonance molecular imaging provides potential promise for early disease diagnosis. In this study, we explore the preparation and characterization of gadolinium (Gd-loaded poly (lactic-co-glycolic acid (PLGA particles surface modified with the Arg-Gly-Asp-Ser (RGDS peptide for the detection of thrombus. PLGA was employed as the carrier-delivery system, and a double emulsion solvent-evaporation method (water in oil in water was used to prepare PLGA particles encapsulating the magnetic resonance contrast agent Gd diethylenetriaminepentaacetic acid (DTPA. To synthesize the Gd-PLGA/chitosan (CS-RGDS particles, carbodiimide-mediated amide bond formation was used to graft the RGDS peptide to CS to form a CS-RGDS film that coated the surface of the PLGA particles. Blank PLGA, Gd-PLGA, and Gd-PLGA/CS particles were fabricated using the same water in oil in water method. Our results indicated that the RGDS peptide successfully coated the surface of the Gd-PLGA/CS-RGDS particles. The particles had a regular shape, smooth surface, relatively uniform size, and did not aggregate. The high electron density of the Gd-loaded particles and a translucent film around the particles coated with the CS and CS-RGDS films could be observed by transmission electron microscopy. In vitro experiments demonstrated that the Gd-PLGA/CS-RGDS particles could target thrombi and could be imaged using a clinical magnetic resonance scanner. Compared with the Gd-DTPA solution, the longitudinal relaxation time of

  3. Surface modification of endovascular stents with rosuvastatin and heparin-loaded biodegradable nanofibers by electrospinning

    Directory of Open Access Journals (Sweden)

    Janjic M

    2017-08-01

    Full Text Available Milka Janjic,1,2 Foteini Pappa,1 Varvara Karagkiozaki,1 Christakis Gitas,2 Kiriakos Ktenidis,2 Stergios Logothetidis1 1Department of Physics, Laboratory for Thin Films – Nanosystems and Nanometrology, University of Thessaloniki, 2School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece Abstract: This study describes the development of drug-loaded nanofibrous scaffolds as a nanocoating for endovascular stents for the local and sustained delivery of rosuvastatin (Ros and heparin (Hep to injured artery walls after endovascular procedures via the electrospinning process.Purpose: The proposed hybrid covered stents can promote re-endothelialization; improve endothelial function; reduce inflammatory reaction; inhibit neointimal hyperplasia of the injured artery wall, due to well-known pleiotropic actions of Ros; and prevent adverse events such as in-stent restenosis (ISR and stent thrombosis (ST, through the antithrombotic action of Hep.Methods: Biodegradable nanofibers were prepared by dissolving cellulose acetate (AC and Ros in N,N-dimethylacetamide (DMAc and acetone-based solvents. The polymeric solution was electrospun (e-spun into drug-loaded AC nanofibers onto three different commercially available stents (Co–Cr stent, Ni–Ti stent, and stainless steel stent, resulting in nonwoven matrices of submicron-sized fibers. Accordingly, Hep solution was further used for fibrous coating onto the engineered Ros-loaded stent. The functional encapsulation of Ros and Hep drugs into polymeric scaffolds further underwent physicochemical analysis. Morphological characterization took place via scanning electron microscopy (SEM and atomic force microscopy (AFM analyses, while scaffolds’ wettability properties were obtained by contact angle (CA measurements.Results: The morphology of the drug-loaded AC nanofibers was smooth, with an average diameter of 200–800 nm, and after CA measurement, we concluded to the superhydrophobic nature

  4. Surface modification of endovascular stents with rosuvastatin and heparin-loaded biodegradable nanofibers by electrospinning

    Science.gov (United States)

    Janjic, Milka; Pappa, Foteini; Karagkiozaki, Varvara; Gitas, Christakis; Ktenidis, Kiriakos; Logothetidis, Stergios

    2017-01-01

    This study describes the development of drug-loaded nanofibrous scaffolds as a nanocoating for endovascular stents for the local and sustained delivery of rosuvastatin (Ros) and heparin (Hep) to injured artery walls after endovascular procedures via the electrospinning process. Purpose The proposed hybrid covered stents can promote re-endothelialization; improve endothelial function; reduce inflammatory reaction; inhibit neointimal hyperplasia of the injured artery wall, due to well-known pleiotropic actions of Ros; and prevent adverse events such as in-stent restenosis (ISR) and stent thrombosis (ST), through the antithrombotic action of Hep. Methods Biodegradable nanofibers were prepared by dissolving cellulose acetate (AC) and Ros in N,N-dimethylacetamide (DMAc) and acetone-based solvents. The polymeric solution was electrospun (e-spun) into drug-loaded AC nanofibers onto three different commercially available stents (Co–Cr stent, Ni–Ti stent, and stainless steel stent), resulting in nonwoven matrices of submicron-sized fibers. Accordingly, Hep solution was further used for fibrous coating onto the engineered Ros-loaded stent. The functional encapsulation of Ros and Hep drugs into polymeric scaffolds further underwent physicochemical analysis. Morphological characterization took place via scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses, while scaffolds’ wettability properties were obtained by contact angle (CA) measurements. Results The morphology of the drug-loaded AC nanofibers was smooth, with an average diameter of 200–800 nm, and after CA measurement, we concluded to the superhydrophobic nature of the engineered scaffolds. In vitro release rates of the pharmaceutical drugs were determined using a high-performance liquid chromatography assay, which showed that after the initial burst, drug release was controlled slowly by the degradation of the polymeric materials. Conclusion These results imply that AC nanofibers

  5. Variations in pCO2 during summer in the surface water of an unproductive lake in northern Sweden

    International Nuclear Information System (INIS)

    Jonsson, A.; Aaberg, J.; Jansson, M.

    2007-01-01

    Unproductive lakes are generally supersaturated with carbon dioxide (CO 2 ) and emit CO 2 to the atmosphere continuously during ice-free periods. However, temporal variation of the partial pressure of CO 2 (pCO 2 ) and thus of CO 2 evasion to atmosphere is poorly documented. We therefore carried out temporally high-resolution (every 6 h) measurements of the pCO 2 using an automated logger system in the surface water of a subarctic, unproductive, lake in the birch forest belt. The study period was June-September 2004. We found that the pCO 2 showed large seasonal variation, but low daily variation. The seasonal variation was likely mainly caused by variations in input and mineralization of allochthonous organic matter. Stratification depth probably also influenced pCO 2 of the surface water by controlling the volume in which mineralization of dissolved organic carbon (DOC) occurred. In lakes, with large variations in pCO 2 , as in our study lake a high (weekly) sampling intensity is recommended for obtaining accurate estimates of the evasion of CO 2

  6. Effect of surface roughness variation on the transmission characteristics of D-shaped fibers with ambient index change

    International Nuclear Information System (INIS)

    Kim, Hyun-Joo; Kwon, Oh-Jang; Han, Young-Geun

    2010-01-01

    The influence of surface roughness on the sensitivity of D-shaped fibers to changes in the ambient index was investigated. In order to obtain D-shaped fibers with different surface roughness, we polished one side of the fibers by using different abrasive grits. The topographies of the surfaces of the polished D-shaped fibers were then observed by using atomic force microscopy (AFM). The light scattered from the rough surfaces of the D-shaped fibers was measured by using optical microscopy. The effect of an ambient index change on the transmission characteristics of D-shaped fibers was measured for various values of the surface roughness. The experimental results indicate that variations in the surface roughness have a considerable influence on the sensitivity of the transmission characteristics of D-shaped fibers to changes in the ambient index.

  7. Study the Robustness Active Filter for a Three-Phase Power Rectifier Considering Line Frequency and Load Variations

    OpenAIRE

    Ali Jafer Mahdi; Bashar Abbas Fadheel

    2017-01-01

    Power electronic converters (e.g. AC-DC and DC-AC) produce harmonics which distorting the waveforms of voltage and current. Many research works have examined various techniques to mitigate harmonics at operating conditions (i.e. at a fixed line frequency and a specific load) such as: (i) passive filters, (ii) Current-injection converters, (iii) active filters and (iv) hybrid filters. Active filters are widely used with three-phase bridge rectifiers due to their excellent features for reducing...

  8. The effect of load and thickness variation on stress analysis of monocoque frame of electric city car using FEM

    Science.gov (United States)

    Makhrojan, Agus; Suprihadi, Agus; Budi, Sigit Setijo; Jamari, J.; Ismail, Rifky

    2017-01-01

    The electric car is transportation which growing and constantly put through improvisation vehicle design. One of the structural components of the electric car which holds a major role is a frame. The purpose of this study is to get monocoque frame design which lightweight and powerful for a city car with two passengers that was able to improve the efficiency of the battery voltage source. Monocoque frame should be able to accept the normal loads such as the weight of batteries, passenger, and body. The most important thing, monocoque frame should also be able to protect the driver and passengers in the event of a collision. Mild steel was chosen for the design because it is easy to obtain and reasonable price as well as easy to shaped for two-seater electric car. FEM (finite element method) was used to determine stress determination and rigidity of the monocoque frame when receiving a static load. The results show that the monocoque frame was still able to withstand the required loads with minimal deflection.

  9. Enhanced proliferation and migration of fibroblasts on the surface of fibroblast growth factor-2-loaded fibrin microthreads.

    Science.gov (United States)

    Cornwell, Kevin G; Pins, George D

    2010-12-01

    Fibrin microthreads are discrete biopolymer fibers, 50-100 μm in diameter, produced from the natural extracellular matrix protein of the provisional matrix that promotes tissue regeneration in the in vivo wound healing environment. The goals of this study were to investigate the feasibility of creating fibrin microthreads containing fibroblast growth factor-2 (FGF-2), and to study the potential of a fibrin matrix to bind signaling proteins known to promote wound healing and regulate cell function in localized cellular microenvironments on scaffold surfaces. FGF-2 was loaded into fibrin microthreads in concentrations ranging from 0 to 200 ng/mL, to investigate the effect of the material on fibroblast attachment, proliferation, cellular outgrowth, and alignment. Although FGF-2-loaded microthreads did not affect fibroblast attachment, they significantly increased cellular outgrowth and proliferation relative to unloaded microthreads. The most pronounced effects were observed at day 7 of cell culture. Further, all of the fibrin microthreads promoted the alignment of fibroblasts and their cytoskeletal components along the long axis of threads, independent of the FGF-2 concentration. Ultimately, we anticipate that these fibrin microthreads will be a promising biopolymer material to promote the regeneration of injured tissues because of their mechanical stability and their matrix signaling capabilities, particularly when loaded with matrix-bound growth factors such as FGF-2.

  10. Modeling viscoelastic deformation of the earth due to surface loading by commercial finite element package - ABAQUS

    Science.gov (United States)

    Kit Wong, Ching; Wu, Patrick

    2017-04-01

    Wu (2004) developed a transformation scheme to model viscoelatic deformation due to glacial loading by commercial finite element package - ABAQUS. Benchmark tests confirmed that this method works extremely well on incompressible earth model. Bangtsson & Lund (2008),however, showed that the transformation scheme would lead to incorrect results if compressible material parameters are used. Their study implies that Wu's method of stress transformation is inadequate to model the load induced deformation of a compressible earth under the framework of ABAQUS. In light of this, numerical experiments are carried out to find if there exist other methods that serve this purpose. All the tested methods are not satisfying as the results failed to converge through iterations, except at the elastic limit. Those tested methods will be outlined and the results will be presented. Possible reasons of failure will also be discussed. Bängtsson, E., & Lund, B. (2008). A comparison between two solution techniques to solve the equations of glacially induced deformation of an elastic Earth. International journal for numerical methods in engineering, 75(4), 479-502. Wu, P. (2004). Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress. Geophysical Journal International, 158(2), 401-408.

  11. Seasonal Variations of the Earth's Gravitational Field: An Analysis of Atmospheric Pressure, Ocean Tidal, and Surface Water Excitation

    Science.gov (United States)

    Dong, D,; Gross, R.S.; Dickey, J.

    1996-01-01

    Monthly mean gravitational field parameters (denoted here as C(sub even)) that represent linear combinations of the primarily even degree zonal spherical harmonic coefficients of the Earth's gravitational field have been recovered using LAGEOS I data and are compared with those derived from gridded global surface pressure data of the National meteorological center (NMC) spanning 1983-1992. The effect of equilibrium ocean tides and surface water variations are also considered. Atmospheric pressure and surface water fluctuations are shown to be the dominant cause of observed annual C(sub even) variations. Closure with observations is seen at the 1sigma level when atmospheric pressure, ocean tide and surface water effects are include. Equilibrium ocean tides are shown to be the main source of excitation at the semiannual period with closure at the 1sigma level seen when both atmospheric pressure and ocean tide effects are included. The inverted barometer (IB) case is shown to give the best agreement with the observation series. The potential of the observed C(sub even) variations for monitoring mass variations in the polar regions of the Earth and the effect of the land-ocean mask in the IB calculation are discussed.

  12. Radiation balance at the surface in the city of São Paulo, Brazil: diurnal and seasonal variations

    NARCIS (Netherlands)

    Ferreira, M.J.; Oliveira, de A.P.; Soares, J.; Codato, G.; Wilde Barbaro, E.; Escobedo, J.F.

    2012-01-01

    The main goal of this work is to describe the diurnal and seasonal variations of the radiation balance components at the surface in the city of São Paulo based on observations carried out during 2004. Monthly average hourly values indicate that the amplitudes of the diurnal cycles of net radiation

  13. Failure of a dampening pin. Combination of dynamic service load and increased notch effect because of surface roughness

    Energy Technology Data Exchange (ETDEWEB)

    Neidel, A.; Riesenbeck, S.; Ullrich, T. [Berlin Gas Turbine Plant (Germany). Materials Testing Laboratory; Voelker, J. [Siemens Gas Turbine Plant (Germany)

    2004-07-01

    As revealed by an inspection of hot gas path components, a dampening pin for the stage 4 moving blades of an industrial gas turbine for power plant applications broke in the summer of 2003. The failure mode of the fractured pin was high cycle fatigue. The root cause of the failure was probably a combination of the dynamic service load and an increased notch effect caused by an increased surface roughness of the pin. In the case of the notch-sensitive material Udimet 720, this was detrimental to the fatigue limit. The measured surface roughness of the failed part was out of specification and traceable to the use of non-OEM (Original Equipment Manufacturer) components. High temperature corrosion did not seem to have played a significant role in the failure mechanism. (orig.)

  14. Spatial distribution, temporal variation and risks of parabens and their chlorinated derivatives in urban surface water in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wenhui; Gao, Lihong [School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Shi, Yali; Wang, Yuan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085 (China); Liu, Jiemin, E-mail: liujm@ustb.edu.cn [School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Cai, Yaqi, E-mail: caiyaqi@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085 (China)

    2016-01-01

    The occurrence and distribution of 13 target compounds, including eight parabens, four chlorinated parabens and p-hydroxybenzoic acid (PHBA), were detected in surface water samples at 35 sampling sites in the Beijing River system, China. The surface water samples were collected from the main rivers and lakes in the urban area monthly from July 2013 to June 2014 (except the frozen period). Laboratory analyses revealed that parabens were ubiquitous in the surface water of Beijing. PHBA was the predominant compound in the surface water samples, with the average concentration of 239 ng L{sup −1}, followed by the total amount of chlorinated parabens (average 50.1 ng/L) and parabens (average 44.3 ng/L). It is noteworthy that octylparaben with longer chain was firstly detected in the surface water. Significant difference was observed for paraben concentrations from different sampling sites, and the highest level of parabens was found in the Xiaotaihou River, which was mainly due to the untreated sewage discharge. Seasonal variation of target compounds in the urban surface water was also studied, and parabens exhibited a different temporal variation from chlorinated derivatives. A combination of factors including high residual chlorine level and water temperature as well as intense ultraviolet radiation might enhance the persistence of chlorinated parabens in chlorinated water during the wet season. Risk assessment showed that parabens and their chlorinated derivatives are not likely to produce biological effects on aquatic ecosystems at current levels in the surface water of Beijing. - Highlights: • Parabens and chlorinated parabens are ubiquitous in surface water in Beijing. • Octylparaben with longer chain was firstly detected in surface water. • Untreated sewage discharge was the main source of parabens in river. • Parabens exhibited a different seasonal variation from chlorinated derivatives. • The risks of target compounds are negligible at

  15. Efficiency of Nanotube Surface-Treated Dental Implants Loaded with Doxycycline on Growth Reduction of Porphyromonas gingivalis.

    Science.gov (United States)

    Ferreira, Cimara Fortes; Babu, Jegdish; Hamlekhan, Azhang; Patel, Sweetu; Shokuhfar, Tolou

    The prevalence of peri-implant infection in patients with dental implants has been shown to range from 28% to 56%. A nanotube-modified implant surface can deliver antibiotics locally and suppress periodontal pathogenic bacterial growth. The aim of this study was to evaluate the deliverability of antibiotics via a nanotube-modified implant. Dental implants with a nanotube surface were fabricated and loaded with doxycycline. Afterward, each dental implant with a nanotube surface was placed into 2-mL tubes, removed from solution, and placed in a fresh solution daily for 28 days. Experimental samples from 1, 2, 4, 16, 24, and 28 days were used for this evaluation. The concentration of doxycycline was measured using spectrophotometric analysis at 273-nm absorbance. The antibacterial effect of doxycycline was evaluated by supplementing Porphyromonas gingivalis (P gingivalis) growth media with the solution collected from the dental implants at the aforementioned time intervals for a period of 48 hours under anaerobic conditions. A bacterial viability assay was used to evaluate P gingivalis growth at 550-nm absorbance. Doxycycline concentration varied from 0.33 to 1.22 μg/mL from day 1 to day 28, respectively. A bacterial viability assay showed the highest P gingivalis growth at day 1 (2 nm) and the lowest at day 4 (0.17 nm), with a gradual reduction from day 1 to day 4 of approximately 87.5%. The subsequent growth pattern was maintained and slightly increased from baseline in approximately 48.3% from day 1 to day 24. The final P gingivalis growth measured at day 28 was 29.4% less than the baseline growth. P gingivalis growth was suppressed in media supplemented with solution collected from dental implants with a nanotube surface loaded with doxycycline during a 28-day time interval.

  16. In situ loading of CuS nanoflowers on rutile TiO2 surface and their improved photocatalytic performance

    International Nuclear Information System (INIS)

    Lu, Y.Y.; Zhang, Y.Y.; Zhang, J.; Shi, Y.; Li, Z.; Feng, Z.C.; Li, C.

    2016-01-01

    Graphical abstract: CuS nanoflowers, fabricated by an element-direct-reaction route using copper and sulfur powder, were loaded on rutile TiO 2 (CuS/TiO 2 ) at low temperature. In photocatalytic degradation of MB or 4-CP, it is found that the surface modification with CuS can enhance the photocatalytic efficiency of TiO 2 . The promotion of photocatalytic performance is mainly ascribed to the enhanced charge separation originating from the well-matched heterostructure between CuS and rutile TiO 2 . - Highlights: • CuS nanoflowers, fabricated by an element-direct-reaction route using copper and sulfur powder, were loaded on rutile TiO 2 at low temperature. • In the photo-degradation studies of MB and 4-CP, surface modification with CuS can enhance the photocatalytic efficiency of rutile TiO 2 . • CuS/TiO 2 composite materials show the good repeatability of the photocatalytic activity. • This work provides a facile method to design and fabricate the effective composites photocatalyst. - Abstract: CuS nanoflowers, fabricated by an element-direct-reaction route using copper and sulfur powder, were loaded on rutile TiO 2 (CuS/TiO 2 ) at low temperature. CuS/TiO 2 composites were utilized as the photocatalysts for the degradation of Methylene Blue (MB) and 4-chlorophenol (4-CP). X-ray diffraction (XRD), UV Raman spectroscopy, transmission electron microscopy (TEM), XPS, and UV-visible diffuse reflectance spectra were used to characterize the crystalline phase, morphology, particle size, and the optical properties of CuS/TiO 2 samples. It is found that CuS/TiO 2 photocatalyst, which CuS are loaded on the surface of rutile TiO 2 , exhibited enhanced photocatalytic degradation of MB (or 4-CP) than TiO 2 or CuS. This indicates that CuS can enhance effectively the photocatalytic activity of rutile TiO 2 by forming heterojunction between CuS and rutile TiO 2 , which is confirmed by photoluminescence (PL) spectra and TEM. Moreover, CuS content has a significant

  17. Automated Measurement for Sensitivity Analysis of Runoff-Sediment Load at Varying Surface Gradients

    Directory of Open Access Journals (Sweden)

    Imanogor P.A.

    2015-07-01

    Full Text Available Direct measurement of surface runoff is often associated with errors and inaccuracies which results to unreliable hydrological data. An automatic Runoff-meter using tipping buckets arrangement calibrated to tip 0.14 liter of runoff water per tip with an accuracy of ± 0.001 litre was used to measure surface runoff from a steel bounded soil tray of dimension (1200 mm X 900 mm X 260 mm filled with sand loamy to the depth of 130 mm and inclined at angle (0 0 , 5 0 ,12 0 and 15 0 horizontal to the instrument. The effect of varying angles of inclination on runoff intensity, sediment loss rate and sediment loss is significant at 5 % confidence level, while surface runoff is not significant at 5 % confidence level. Total highest sediment loss of 458.2 g and 313.4 g were observed at angle 15 0 and 12 0 respectively. Total surface runoff of 361.5 mm and 445.8 mm were generated at inclined angle of 0 0 and 5 0 , while at angle 12 0 and 15 0 , 564.3 mm and 590.0 mm of surface runoff were generated. In addition, runoff intensity and sediment loss rate were highest at angle 15 0 , while the lowest values of 1.5mm/min and 5.43 g/min were obtained at angle of inclination 5 0 . The results showed that strong relationship existed among the hydrological variables as a result of subjecting the steel bounded soil tray to different angles of inclination. Such results would provide useful data for the running of physics-based deterministic model of surface runoff and erosion which will be useful for the design of hydrological structures, land use planning and management.

  18. Leishmania-specific surface antigens show sub-genus sequence variation and immune recognition.

    Directory of Open Access Journals (Sweden)

    Daniel P Depledge

    2010-09-01

    Full Text Available A family of hydrophilic acylated surface (HASP proteins, containing extensive and variant amino acid repeats, is expressed at the plasma membrane in infective extracellular (metacyclic and intracellular (amastigote stages of Old World Leishmania species. While HASPs are antigenic in the host and can induce protective immune responses, the biological functions of these Leishmania-specific proteins remain unresolved. Previous genome analysis has suggested that parasites of the sub-genus Leishmania (Viannia have lost HASP genes from their genomes.We have used molecular and cellular methods to analyse HASP expression in New World Leishmania mexicana complex species and show that, unlike in L. major, these proteins are expressed predominantly following differentiation into amastigotes within macrophages. Further genome analysis has revealed that the L. (Viannia species, L. (V. braziliensis, does express HASP-like proteins of low amino acid similarity but with similar biochemical characteristics, from genes present on a region of chromosome 23 that is syntenic with the HASP/SHERP locus in Old World Leishmania species and the L. (L. mexicana complex. A related gene is also present in Leptomonas seymouri and this may represent the ancestral copy of these Leishmania-genus specific sequences. The L. braziliensis HASP-like proteins (named the orthologous (o HASPs are predominantly expressed on the plasma membrane in amastigotes and are recognised by immune sera taken from 4 out of 6 leishmaniasis patients tested in an endemic region of Brazil. Analysis of the repetitive domains of the oHASPs has shown considerable genetic variation in parasite isolates taken from the same patients, suggesting that antigenic change may play a role in immune recognition of this protein family.These findings confirm that antigenic hydrophilic acylated proteins are expressed from genes in the same chromosomal region in species across the genus Leishmania. These proteins are

  19. Synoptic Sampling to Determine Distributed Groundwater-Surface Water Nitrate Loading and Removal Potential Along a Lowland River

    Science.gov (United States)

    Pai, Henry; Villamizar, Sandra R.; Harmon, Thomas C.

    2017-11-01

    Delineating pollutant reactive transport pathways that connect local land use patterns to surface water is an important goal. This work illustrates high-resolution river mapping of salinity or specific conductance (SC) and nitrate (NO3-) as a potential part of achieving this goal. We observed longitudinal river SC and nitrate distributions using high-resolution synoptic in situ sensing along the lower Merced River (38 river km) in Central California (USA) from 2010 to 2012. We calibrated a distributed groundwater-surface water (GW-SW) discharge model for a conservative solute using 13 synoptic SC sampling events at flows ranging from 1.3 to 31.6 m3 s-1. Nitrogen loads ranged from 0.3 to 1.6 kg N d-1 and were greater following an extended high flow period during a wet winter. Applying the distributed GW-SW discharge estimates to a simplistic reactive nitrate transport model, the model reproduced observed river nitrate distribution well (RRMSE = 5-21%), with dimensionless watershed-averaged nitrate removal (kt) ranging from 0 to 0.43. Estimates were uncertain due to GW nitrate data variability, but the resulting range was consistent with prior removal estimates. At the segment scale, estimated GW-SW nitrate loading ranged from 0 to 17 g NO3- s-1 km-1. Local loading peaked near the middle of the study reach, a location that coincides with a shallow clay lens and with confined animal feed operations in close proximity to the river. Overall, the results demonstrate the potential for high-resolution synoptic monitoring to support GW-SW modeling efforts aimed at understanding and managing nonpoint source pollution.

  20. Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

    Science.gov (United States)

    Yu, Liang; Rozemeijer, Joachim; van Breukelen, Boris M.; Ouboter, Maarten; van der Vlugt, Corné; Broers, Hans Peter

    2018-01-01

    organic matter in subsurface sediments coupled to sulfate reduction and possibly methanogenesis. The large loads of nutrient-rich groundwater seepage into the deepest polders indirectly affect surface water quality in the surrounding area, because excess water from the deep polders is pumped out and used to supply water to the surrounding infiltrating polders in dry periods. The study shows the importance of the connection between groundwater and surface water nutrient chemistry in the greater Amsterdam area. We expect that taking account of groundwater-surface water interaction is also important in other subsiding and urbanising deltas around the world, where water is managed intensively in order to enable agricultural productivity and achieve water-sustainable cities.

  1. Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

    Directory of Open Access Journals (Sweden)

    L. Yu

    2018-01-01

    from the decomposition of organic matter in subsurface sediments coupled to sulfate reduction and possibly methanogenesis. The large loads of nutrient-rich groundwater seepage into the deepest polders indirectly affect surface water quality in the surrounding area, because excess water from the deep polders is pumped out and used to supply water to the surrounding infiltrating polders in dry periods. The study shows the importance of the connection between groundwater and surface water nutrient chemistry in the greater Amsterdam area. We expect that taking account of groundwater–surface water interaction is also important in other subsiding and urbanising deltas around the world, where water is managed intensively in order to enable agricultural productivity and achieve water-sustainable cities.

  2. Local electron tomography using angular variations of surface tangents: Stomo version 2

    Science.gov (United States)

    Petersen, T. C.; Ringer, S. P.

    2012-03-01

    In a recent publication, we investigated the prospect of measuring the outer three-dimensional (3D) shapes of nano-scale atom probe specimens from tilt-series of images collected in the transmission electron microscope. For this purpose alone, an algorithm and simplified reconstruction theory were developed to circumvent issues that arise in commercial "back-projection" computations in this context. In our approach, we give up the difficult task of computing the complete 3D continuum structure and instead seek only the 3D morphology of internal and external scattering interfaces. These interfaces can be described as embedded 2D surfaces projected onto each image in a tilt series. Curves and other features in the images are interpreted as inscribed sets of tangent lines, which intersect the scattering interfaces at unknown locations along the direction of the incident electron beam. Smooth angular variations of the tangent line abscissa are used to compute the surface tangent intersections and hence the 3D morphology as a "point cloud". We have published the explicit details of our alternative algorithm along with the source code entitled "stomo_version_1". For this work, we have further modified the code to efficiently handle rectangular image sets, perform much faster tangent-line "edge detection" and smoother tilt-axis image alignment using simple bi-linear interpolation. We have also adapted the algorithm to detect tangent lines as "ridges", based upon 2nd order partial derivatives of the image intensity; the magnitude and orientation of which is described by a Hessian matrix. Ridges are more appropriate descriptors for tangent-line curves in phase contrast images outlined by Fresnel fringes or absorption contrast data from fine-scale objects. Improved accuracy, efficiency and speed for "stomo_version_2" is demonstrated in this paper using both high resolution electron tomography data of a nano-sized atom probe tip and simulated absorption-contrast images

  3. Impacts of early autumn Arctic sea ice concentration on subsequent spring Eurasian surface air temperature variations

    Science.gov (United States)

    Chen, Shangfeng; Wu, Renguang

    2017-11-01

    This study reveals a close relation between autumn Arctic sea ice change (SIC) in the Laptev Sea-eastern Siberian Sea-Beaufort Sea and subsequent spring Eurasian surface air temperature (SAT) variation. Specifically, more (less) SIC over the above regions in early autumn generally correspond to SAT warming (cooling) over the mid-high latitudes of Eurasia during subsequent spring. Early autumn Arctic SIC affects spring Eurasian SAT via modulating spring Arctic Oscillation (AO) associated atmospheric changes. The meridional temperature gradient over the mid-high latitudes decreases following the Arctic sea ice loss. This results in deceleration of prevailing westerly winds over the mid-latitudes of the troposphere, which leads to increase in the upward propagation of planetary waves and associated Eliassen-Palm flux convergence in the stratosphere over the mid-high latitudes. Thereby, westerly winds in the stratosphere are reduced and the polar vortex is weakened. Through the wave-mean flow interaction and downward propagation of zonal wind anomalies, a negative spring AO pattern is formed in the troposphere, which favors SAT cooling over Eurasia. The observed autumn Arctic SIC-spring Eurasian SAT connection is reproduced in the historical simulation (1850-2005) of the flexible global ocean-atmosphere-land system model, spectral version 2 (FGOALS-s2). The FGOALS-s2 also simulates the close connection between autumn SIC and subsequent spring AO. Further analysis suggests that the prediction skill of the spring Eurasian SAT was enhanced when taking the autumn Arctic SIC signal into account.

  4. Mirror and grating surface figure requirements for grazing incidence synchrotron radiation beamlines: Power loading effects

    Energy Technology Data Exchange (ETDEWEB)

    Hulbert, S.L.; Sharma, S.

    1987-01-01

    At present, grazing incidence mirrors are used almost exclusively as the first optical element in VUV and soft x-ray synchrotron radiation beamlines. The performance of these mirrors is determined by thermal and mechanical stress-induced figure errors as well as by figure errors remaining from the grinding and polishing process. With the advent of VUV and soft x-ray undulators and wigglers has come a new set of thermal stress problems related to both the magnitude and the spatial distribution of power from these devices. In many cases the power load on the entrance slits and gratings in these beamlines is no longer negligible. The dependence of thermally-induced front-end mirror figure errors on various storage ring and insertion device parameters (especially those at the National Synchrotron Light Source) and the effects of these figure errors on two classes of soft x-ray beamlines are presented.

  5. Evaluation of the relation between groundwater pollution and the pollutant load on surface waters

    NARCIS (Netherlands)

    Groenendijk, P.; Roest, C.W.J.

    1996-01-01

    The importance of the relation between groundwater and surface water is demonstrated by the impact of water quality standards on permissible nitrogen losses at farm level. The effects of the intended fertilization reduction measures on agricultural production justify a thorough examination of the

  6. Analysis of cross-section surface roughness evolution of carbon fibre reinforced polymer under fatigue loading

    Czech Academy of Sciences Publication Activity Database

    Doktor, T.; Valach, Jaroslav; Kytýř, Daniel; Fíla, Tomáš; Minster, Jiří; Kostelecká, M.

    2012-01-01

    Roč. 106, č. 3 (2012), s399-s400 ISSN 0009-2770 Institutional support: RVO:68378297 Keywords : surface roughness * degradation monitoring * SEM * LSCM Subject RIV: JI - Composite Materials Impact factor: 0.453, year: 2012 http://www.chemicke-listy.cz/common/content-issue_s2-volume_106-year_2012.html

  7. Equations for the calculation of N- and P-load on surface waters

    NARCIS (Netherlands)

    Steenvoorden, J.H.A.M.

    1983-01-01

    Nutrient loadson surface and ground waters is the result of inputs from various sources. For the development of a plan for water management information is needed about the consequences of alternative scenarios. Therefore mathematica! approaches have been developed for the contributions by the

  8. Experiment on temporal variation of bed load transport in response to changes in sediment supply in streams

    Science.gov (United States)

    Elgueta-Astaburuaga, Maria A.; Hassan, Marwan A.

    2017-01-01

    A flume experiment was conducted to study channel adjustment to episodic sediment supply in mountain streams. The bulk sediment used for the bed and feed included grain sizes 0.5-64 mm with geometric mean Dg>(bulk>) of 5.7 mm. Water discharge was held constant for 40 h, and 300 kg of sediment was supplied through a range of scenarios. Bed slope, sediment storage, sediment transport, and bed surface texture responded to sediment supply. During the first of seven runs, bed slope decreased from 0.022 m/m (flume slope) to 0.018 m/m due to sediment starvation. Bed slope increased beginning in the second run as the bed aggraded due to preferential storage of grains >8 mm. Transport rate and bed-surface particle size were significantly affected by magnitude-frequency of sediment feed. Under constant feed, transport rate increased gradually and Dg >(surface>) ranged between 12 and 15 mm. Instead, sediment pulses caused a pronounced increase in sediment transport rate and surface fining, trends that were inverted as sediment evacuated. At the run scale, sediment transport and storage behaved as with constant feed if pulse relaxation time exceeded time between pulses. The increase in transport rate and surface fining were proportional to pulse size. After the 300 kg pulse, transport rate reached 100 g m-1 s-1 and Dg >(surface>) was g >(surface>) was >12 mm. Textural differences on the initial bed surface influenced the patterns of sediment transport. Channel adjustment was controlled by magnitude-frequency of sediment feed and not by total feed.

  9. Variation of Extreme and Fatigue Design Loads on the Main Bearing of a Front Mounted Direct Drive System

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Natarajan, Anand

    2016-01-01

    on the thrust and bending moments at the main bearing, both for ultimate design and in fatigue. It is found that the initial superconductor generator weight of 363 tons must be reduced by 25% in order not to result in higher extreme loads on main and yaw bearing than the reference10 MW geared reference drive...... train. A weight reduction of 50% is needed in order to maintain main bearing fatigue damage equivalent to the reference drive train. Thus a target mass of front mounted superconducting direct drive generators is found to be between 183-272 tons....

  10. Role of surface on the size-dependent mechanical properties of copper nanowire under tensile load: A molecular dynamics simulation

    International Nuclear Information System (INIS)

    Liu, Wei-Ting; Hsiao, Chun-I.; Hsu, Wen-Dung

    2014-01-01

    In this study we have used atomistic simulations to investigate the role of surface on the size-dependent mechanical properties of nanowires. In particular, we have performed computational investigation on single crystal face-centered cubic copper nano-wires with diameters ranging from 2 to 20 nm. The wire axis for all the nanowires are considered along the [0 0 1] direction. Characterization of the initial optimized structures revealed clear differences in interatomic spacing, stress, and potential energy in all the nanowires. The mechanical properties with respect to wire diameter are evaluated by applying tension along the [0 0 1] direction until yielding. We have discussed the stress–strain relationships, Young's modulus, and the variation in potential energy from surface to the center of the wire for all the cases. Our results indicate that the mechanical response (including yield strain, Young's modulus, and resilience) is directly related to the proportion of surface to bulk type atoms present in each nanowire. Thus the size-dependent mechanical properties of single crystal copper nanowire within elastic region are attributed to the surface to volume ratio (surface effect). Using the calculated response, we have formulated a mathematical relationship, which predicts the nonlinear correlation between the mechanical properties and the diameter of the wire.

  11. Flight Investigation on a Fighter-Type Airplane of Factors which Affect the Loads and Load Distributions on the Vertical Tail Surfaces During Rudder Kicks and Fishtails

    Science.gov (United States)

    1947-08-01

    is not&d to decresse with increase of pedel force; or amount of resistance to deflection. This result is in agreement wi"& the results of tests made...Vertical-Tail Loads In Rollin Yull-Out Mmcuvers~ NACA CB No. L4rn4, 1944. 5. Boshm, Job , and Davis, Philip: Consideration of I$-namk Loads on the

  12. Deuterium supersaturation in low-energy plasma-loaded tungsten surfaces

    Science.gov (United States)

    Gao, L.; Jacob, W.; von Toussaint, U.; Manhard, A.; Balden, M.; Schmid, K.; Schwarz-Selinger, T.

    2017-01-01

    Fundamental understanding of hydrogen-metal interactions is challenging due to a lack of knowledge on defect production and/or evolution upon hydrogen ingression, especially for metals undergoing hydrogen irradiation with ion energy below the displacement thresholds reported in literature. Here, applying a novel low-energy argon-sputter depth profiling method with significantly improved depth resolution for tungsten (W) surfaces exposed to deuterium (D) plasma at 300 K, we show the existence of a 10 nm thick D-supersaturated surface layer (DSSL) with an unexpectedly high D concentration of ~10 at.% after irradiation with ion energy of 215 eV. Electron back-scatter diffraction reveals that the W lattice within this DSSL is highly distorted, thus strongly blurring the Kikuchi pattern. We explain this strong damage by the synergistic interaction of energetic D ions and solute D atoms with the W lattice. Solute D atoms prevent the recombination of vacancies with interstitial W atoms, which are produced by collisions of energetic D ions with W lattice atoms (Frenkel pairs). This proposed damaging mechanism could also be active on other hydrogen-irradiated metal surfaces. The present work provides deep insight into hydrogen-induced lattice distortion at plasma-metal interfaces and sheds light on its modelling work.

  13. Development of tea tree oil-loaded liposomal formulation using response surface methodology.

    Science.gov (United States)

    Ge, Yan; Ge, Mingqiao

    2015-03-23

    The aim of this study is to prepare tea tree oil liposome (TTOL) and optimize the preparation condition by single factor experiment and statistical design. TTOL was prepared using a thin-film hydration with the combination of sonication method and the preparation conditions of TTOL were optimized with response surface methodology (RSM). The optimal preparation conditions for TTOL by response surface methodology were as follows: the mass ratio of PC and Cho 5.51, TTO concentration 1.21% (v/v) and Tween 80 concentration 0.79% (v/v). The response surface analysis showed that the significant (p  0.05) lack of fit for the reduced models. Furthermore, the interaction of the mass ratio of PC/Cho and TTO concentration had a significant effect. The amounts of Tween 80 required were also reduced with RSM. Under these conditions, the experimental encapsulation efficiency of TTOL was 97.81 ± 0.33%, which was close with the predicted value. Therefore, the optimized preparation condition was very reliable. The increased entrapment efficiency would significantly improve the TTO stability and bioavailability.

  14. Enhanced protein loading on a planar Si(111)-H surface with second generation NTA

    Science.gov (United States)

    Liu, Xiang; Han, Huan-Mei; Liu, Hong-Bo; Xiao, Shou-jun

    2010-08-01

    A Si(111)-H surface was modified via a direct reaction between Si-H and 1-undecylenic acid (UA) under microwave irradiation to form molecular monolayers with terminal carboxyl groups. After esterifying carboxylic acid being esterified with N-hydroxysuccinimide (NHS), aminobutyl nitrilotriacetic acid (ANTA) was bound to the silicon surface through amidation (pH = 8.0) between its primary amino group and NHS-ester, producing nitrilotriacetic acid (NTA) anions. Then hexa-histidine tagged thioredoxin-urodilatin (his-tagged protein) and FITC-labeled hexa-histidine tagged thioredoxin-urodilatin (FITC-his-tagged protein) can be anchored after NTA was coordinated with Ni 2+. Furthermore, the NTA-terminated chip was acidified with 0.1 M HCl and subsequently esterified with NHS and then amidated with ANTA again to produce a second generation NTA. Thus the surface density of nitrilotriacetic acid anions was improved and resultantly that of anchored proteins was also enhanced through the iterative reactions. Both multiple transmission-reflection infrared spectroscopy (MTR-IR) and fluorescence scanning measurements demonstrated a proximate 1.63 times of anchored proteins on the second generation NTA/Ni 2+ as that on the first generation NTA/Ni 2+ monolayer.

  15. Poloidal density variation of impurities in a rotating tokamak plasma - flux surface coordinates and effect on transport coefficients

    International Nuclear Information System (INIS)

    Romanelli, M.

    1999-09-01

    The poloidal variation of impurity densities over magnetic surfaces brings about an enhancement of neoclassical transport coefficients, as shown by Romanelli and Ottaviani for impurities in the Pfirsch Schlueter regime and by Helander for particles in the banana-plateau regime, both in a large aspect ratio tokamak. The same effect will occur in a finite aspect ratio tokamak and therefore it is considered to be relevant for inclusion in transport codes for comparison with the experimental measurements of impurity transport. Here an expression for the impurity-density poloidal-variation generated by the fast toroidal rotation of the plasma column is presented in general coordinates. (author)

  16. Seasonal and spatial variations in microbial activity at various phylogenetic resolutions at a groundwater – surface water interface

    DEFF Research Database (Denmark)

    Yu, Ran; Smets, Barth F.; Gan, Ping

    2014-01-01

    We investigated the seasonal and spatial variation in activity and density of the metabolically active in situ microbial community (AIMC) at a landfill leachate-impacted groundwater – surface water interface (GSI). A series of AIMC traps were designed and implemented for AIMC sampling and microbial...... analysis. Consistently higher microbial activities with less variation in depth were measured in the AIMC traps than in the ambient sediments. Flood disturbance appeared to control AIMC activity distributions at the gradually elevated GSI. The highest AIMC activities were generally obtained from locations...

  17. [The relationship between the variation rate of MODIS land surface temperature and AMSR-E soil moisture and its application to downscaling].

    Science.gov (United States)

    Wang, An-Qi; Xie, Chao; Shi, Jian-Cheng; Gong, Hui-Li

    2013-03-01

    Using AMSR-E soil moisture, MODIS land surface temperature (Ts) and vegetation index product, the authors discuss the relationship between the variation rate of land surface temperature and surface soil moisture. Selecting the plains region of central United States as the study area, the authors propose the distribution triangle of the variation rate of land surface temperature and soil moisture. In the present paper, temperature variation and vegetation index (TVVI), a new index containing the information of temperature variation and vegetation, is introduced. The authors prove that TVVI and soil moisture show a steady relationship of exponential function; and build a quantitative model of soil moisture(SM) and instantaneous surface temperature variation (VTs). The authors later achieve downscaling of AMSR-E soil moisture data, through the above stated functional relationships and high-resolution MODIS data. Comparison with measured data on ground surface indicates that this method of downscaling is of high precision

  18. Decadal variations in estimated surface solar radiation over Switzerland since the late 19th century

    Directory of Open Access Journals (Sweden)

    A. Sanchez-Lorenzo

    2012-09-01

    Full Text Available Our knowledge on trends in surface solar radiation (SSR involves uncertainties due to the scarcity of long-term time series of SSR, especially with records before the second half of the 20th century. Here we study the trends of all-sky SSR from 1885 to 2010 in Switzerland, which have been estimated using a homogenous dataset of sunshine duration series. This variable is shown to be a useful proxy data of all-sky SSR, which can help to solve some of the current open issues in the dimming/brightening phenomenon. All-sky SSR has been fairly stable with little variations in the first half of the 20th century, unlike the second half of the 20th century that is characterized also in Switzerland by a dimming from the 1950s to the 1980s and a subsequent brightening. Cloud cover changes seem to explain the major part of the decadal variability observed in all-sky SSR, at least from 1885 to the 1970s; at this point, a discrepancy in the sign of the trend is visible in the all-sky SSR and cloud cover series from the 1970s to the present. Finally, an attempt to estimate SSR series for clear-sky conditions, based also on sunshine duration records since the 1930s, has been made for the first time. The mean clear-sky SSR series shows no relevant changes between the 1930s to the 1950s, then a decrease, smaller than the observed in the all-sky SSR, from the 1960s to 1970s, and ends with a strong increase from the 1980s up to the present. During the three decades from 1981 to 2010 the estimated clear-sky SSR trends reported in this study are in line with previous findings over Switzerland based on direct radiative flux measurements. Moreover, the signal of the El Chichón and Pinatubo volcanic eruption visible in the estimated clear-sky SSR records further demonstrates the potential to infer aerosol-induced radiation changes from sunshine duration observations.

  19. Predicting Indian Summer Monsoon onset through variations of surface air temperature and relative humidity

    Science.gov (United States)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Indian Summer Monsoon (ISM) rainfall has an enormous effect on Indian agriculture, economy, and, as a consequence, life and prosperity of more than one billion people. Variability of the monsoonal rainfall and its onset have a huge influence on food production, agricultural planning and GDP of the country, which on 22% is determined by agriculture. Consequently, successful forecasting of the ISM onset is a big challenge and large efforts are being put into it. Here, we propose a novel approach for predictability of the ISM onset, based on critical transition theory. The ISM onset is defined as an abrupt transition from sporadious rainfall to spatially organized and temporally sustained rainfall. Taking this into account, we consider the ISM onset as is a critical transition from pre-monsoon to monsoon, which take place in time and also in space. It allows us to suggest that before the onset of ISM on the Indian subcontinent should be areas of critical behavior where indicators of the critical transitions can be detected through an analysis of observational data. First, we identify areas with such critical behavior. Second, we use detected areas as reference points for observation locations for the ISM onset prediction. Third, we derive a precursor for the ISM onset based on the analysis of surface air temperature and relative humidity variations in these reference points. Finally, we demonstrate the performance of this precursor on two observational data sets. The proposed approach allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. The ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In the anomalous years, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the

  20. Sea-surface salinity variations in the northern Caribbean Sea across the Mid-Pleistocene Transition

    Directory of Open Access Journals (Sweden)

    S. Sepulcre

    2011-02-01

    Full Text Available By reconstructing past hydrologic variations in the Northern Caribbean Sea and their influence on the stability of the Atlantic Meridional Overturning Circulation (AMOC during the last 940 ka, we seek to document climate changes in this tropical area in response to the Mid-Pleistocene Transition (MPT. Using core MD03-2628, we estimated past changes in sea surface salinity (SSS using Δδ18O, the difference between the modern, and the past δ18O of seawater (obtained by combining alkenone thermometer data with the δ18O of the planktonic foraminifera Globigerinoides rube (white and corrected for ice-sheet volume effects. Today, the lowest SSS values in the area studied are associated with the northernmost location of the Inter-Tropical Convergence Zone (ITCZ. The Δδ18O record obtained from core MD03-2628 exhibits glacial/interglacial cyclicity with higher values during all glacial periods spanning the last 940 ka, indicating increased SSS. A long-term trend was also observed in the Δδ18O values that exhibited a shift toward lower values for interglacial periods during the last 450 ka, as compared to interglacial stages older than 650 ka. A rise in SSS during glacial stages may be related to the southernmost location of the ITCZ, which is induced by a steeper cross-equator temperature gradient and associated with reduced northward cross-equatorial oceanic transport. Therefore, the results suggest a permanent link between the tropical salinity budget and the AMOC during the last 940 ka. Following the MPT, lower salinities during the last five interglacial stages indicated a northernmost ITCZ location that was forced by changes in the cross-equator temperature gradient and that was associated with the poleward position of Southern Oceanic Fronts that amplify the transport of heat and moisture to the North Atlantic. These processes may have contributed to the amplification of the

  1. Surface modification of paclitaxel-loaded tri-block copolymer PLGA- b-PEG- b-PLGA nanoparticles with protamine for liver cancer therapy

    Science.gov (United States)

    Gao, Nansha; Chen, Zhihong; Xiao, Xiaojun; Ruan, Changshun; Mei, Lin; Liu, Zhigang; Zeng, Xiaowei

    2015-08-01

    In order to enhance the therapeutic effect of chemotherapy on liver cancer, a biodegradable formulation of protamine-modified paclitaxel-loaded poly(lactide- co-glycolide)- b-poly(ethylene glycol)- b-poly(lactide- co-glycolide) (PLGA- b-PEG- b-PLGA) nanoparticles (PTX-loaded/protamine NPs) was prepared. Tri-block copolymer PLGA- b-PEG- b-PLGA was synthesized by ring-opening polymerization and characterized by 1H NMR spectroscopy and gel permeation chromatography. PTX-loaded and PTX-loaded/protamine NPs were characterized in terms of size, size distribution, zeta potential, surface morphology, drug encapsulation efficiency, and drug release. Confocal laser scanning microscopy showed that coumarin 6-loaded/protamine NPs were internalized by hepatocellular carcinoma cell line HepG2. The cellular uptake efficiency of NPs was obviously elevated after protamine modification. With commercial formulation Taxol® as the reference, HepG2 cells were also used to study the cytotoxicity of the NPs. PTX-loaded/protamine NPs exhibited significantly higher cytotoxicity than PTX-loaded NPs and Taxol® did. All the results suggested that surface modification of PTX-loaded PLGA- b-PEG- b-PLGA NPs with protamine boosted the therapeutic efficacy on liver cancer.

  2. Surface modification of paclitaxel-loaded tri-block copolymer PLGA-b-PEG-b-PLGA nanoparticles with protamine for liver cancer therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Nansha [Chinese Academy of Science, Research Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology (China); Chen, Zhihong [Guangdong Medical College, Analysis Centre (China); Xiao, Xiaojun [Shenzhen University, Institute of Allergy and Immunology, School of Medicine (China); Ruan, Changshun [Chinese Academy of Science, Research Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology (China); Mei, Lin [Tsinghua University, The Shenzhen Key Lab of Gene and Antibody Therapy, and Division of Life and Health Sciences, Graduate School at Shenzhen (China); Liu, Zhigang, E-mail: lzg@szu.edu.cn [Shenzhen University, Institute of Allergy and Immunology, School of Medicine (China); Zeng, Xiaowei, E-mail: zeng.xiaowei@sz.tsinghua.edu.cn [Tsinghua University, The Shenzhen Key Lab of Gene and Antibody Therapy, and Division of Life and Health Sciences, Graduate School at Shenzhen (China)

    2015-08-15

    In order to enhance the therapeutic effect of chemotherapy on liver cancer, a biodegradable formulation of protamine-modified paclitaxel-loaded poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-b-PEG-b-PLGA) nanoparticles (PTX-loaded/protamine NPs) was prepared. Tri-block copolymer PLGA-b-PEG-b-PLGA was synthesized by ring-opening polymerization and characterized by {sup 1}H NMR spectroscopy and gel permeation chromatography. PTX-loaded and PTX-loaded/protamine NPs were characterized in terms of size, size distribution, zeta potential, surface morphology, drug encapsulation efficiency, and drug release. Confocal laser scanning microscopy showed that coumarin 6-loaded/protamine NPs were internalized by hepatocellular carcinoma cell line HepG2. The cellular uptake efficiency of NPs was obviously elevated after protamine modification. With commercial formulation Taxol{sup ®} as the reference, HepG2 cells were also used to study the cytotoxicity of the NPs. PTX-loaded/protamine NPs exhibited significantly higher cytotoxicity than PTX-loaded NPs and Taxol{sup ®} did. All the results suggested that surface modification of PTX-loaded PLGA-b-PEG-b-PLGA NPs with protamine boosted the therapeutic efficacy on liver cancer.

  3. High-frequency pressure variations in the vicinity of a surface CO2 flux chamber

    Science.gov (United States)

    Eugene S. Takle; James R. Brandle; R. A. Schmidt; Rick Garcia; Irina V. Litvina; William J. Massman; Xinhua Zhou; Geoffrey Doyle; Charles W. Rice

    2003-01-01

    We report measurements of 2Hz pressure fluctuations at and below the soil surface in the vicinity of a surface-based CO2 flux chamber. These measurements were part of a field experiment to examine the possible role of pressure pumping due to atmospheric pressure fluctuations on measurements of surface fluxes of CO2. Under the moderate wind speeds, warm temperatures,...

  4. SIMULATION OF TEMPERATURE AND TRANSPORT LOAD IMPACT ON FORMATION AND DEVELOPMENT OF CRACKS ON ASPHALT-CONCRETE ROAD SURFACES

    Directory of Open Access Journals (Sweden)

    I. S. Melnikova

    2012-01-01

    Full Text Available An analysis of statistical data has shown that about 60 % of all types of road surface destructions and damages in the Republic of Belarus are attributed to cracks (separate, frequent and cracks network. The process of cracks formation in the asphalt concrete pavement is rather complicated and it is affected by a number of factors. The most important and determining factors are character and value of traffic loads, temperature action, road pavement structure, properties of materials used for its layers. Some regularities of the cracks formation and development in the asphalt-concrete layers of the pavement have been established on the basis of the physical and mathematical modeling. Application of a finite  element  method for  calculations  has made it possible to determine  numerical values of compressive and tensile stresses arising due to temperature action and traffic load, deflection of road pavement constructive layers. The paper contains recommendations for a road pavement design and repair of asphalt-concrete pavements which have been made on the basis of the obtained data analysis.

  5. Investigation of the load on the lumbar region in nursing technique's movements - relation between twist and surface electromyogram.

    Science.gov (United States)

    Maekawa, Yasuko; Shiozaki, Akira; Majima, Yukie

    2009-01-01

    This study measured the twist angle of the lumbar region and the surface electromyogram (EMG) and examined their mutual relation to elucidate the degree and influence of factors of "twist" in nursing techniques as a cause of lower back pain. Using a goniometer (two-way angle and twist sensors) and an EMG(SX230; DKH Co., Ltd.), we conducted measurements by affixing the goniometer on the lumbar vertebral column and EMG sensor at four points of right and left sides of L2 and L4 (of the erector muscle of the spine). The measured nursing techniques were three common methods of "transferring a patient from bed to wheelchair," which is said to impart a heavy load on the lumbar region. Results show that the correlation value between the twist angle rate and mean energy is likely to be greater, suggesting that the magnitude of the load on the lumbar region should be related to the twist speed rather than to the twist angle of the movement itself.

  6. Genotypic variation in grain P loading across diverse rice growing environments and implications for field P balances

    Directory of Open Access Journals (Sweden)

    Elke Vandamme

    2016-09-01

    Full Text Available More than 60% of phosphorus (P taken up by rice (Oryza spp is accumulated in the grains at harvest and hence exported from fields, leading to a continuous removal of P. If P removed from fields is not replaced by P inputs then soil P stocks decline, with consequences for subsequent crops. Breeding rice genotypes with a low concentration of P in the grains could be a strategy to reduce maintenance fertilizer needs and slow soil P depletion in low input systems. This study aimed to assess variation in grain P concentrations among rice genotypes across diverse environments and evaluate the implications for field P balances at various grain yield levels. Multi-location screening experiments were conducted at different sites across Africa and Asia and yield components and grain P concentrations were determined at harvest. Genotypic variation in grain P concentration was evaluated while considering differences in P supply and grain yield using cluster analysis to group environments and boundary line analysis to determine minimum grain P concentrations at various yield levels. Average grain P concentrations across genotypes varied almost 3-fold among environments, from 1.4 to 3.9 mg g-1. Minimum grain P concentrations associated with grain yields of 150, 300 and 500 g m-2 varied between 1.2 and 1.7, 1.3 and 1.8 and 1.7 and 2.2 mg g-1 among genotypes respectively. Two genotypes, Santhi Sufaid and DJ123, were identified as potential donors for low grain P concentration. Improvements in P balances that could be achieved by exploiting this genotypic variation are in the range of less than 0.10 g P m-2 (1 kg P ha-1 in low yielding systems, and 0.15 to 0.50 g P m-2 (1.5-5.0 kg P ha-1 in higher yielding systems. Improved crop management and alternative breeding approaches may be required to achieve larger reductions in grain P concentrations in rice.

  7. Chiral nematic self-assembly of minimally surface damaged chitin nanofibrils and its load bearing functions

    Science.gov (United States)

    Oh, Dongyeop X.; Cha, Yun Jeong; Nguyen, Hoang-Linh; Je, Hwa Heon; Jho, Yong Seok; Hwang, Dong Soo; Yoon, Dong Ki

    2016-03-01

    Chitin is one of the most abundant biomaterials in nature, with 1010 tons produced annually as hierarchically organized nanofibril fillers to reinforce the exoskeletons of arthropods. This green and cheap biomaterial has attracted great attention due to its potential application to reinforce biomedical materials. Despite that, its practical use is limited since the extraction of chitin nanofibrils requires surface modification involving harsh chemical treatments, leading to difficulties in reproducing their natural prototypal hierarchical structure, i.e. chiral nematic phase. Here, we develop a chemical etching-free approach using calcium ions, called “natural way”, to disintegrate the chitin nanofibrils while keeping the essential moiety for the self-assembly, ultimately resulting in the reproduction of chitin’s natural chiral structure in a polymeric matrix. This chiral chitin nanostructure exceptionally toughens the composite. Our resultant chiral nematic phase of chitin materials can contribute to the understanding and use of the reinforcing strategy in nature.

  8. Preparation, characterization, and optimization of altretamine-loaded solid lipid nanoparticles using Box-Behnken design and response surface methodology.

    Science.gov (United States)

    Gidwani, Bina; Vyas, Amber

    2016-01-01

    The objective of the present study was to prepare solid lipid nanoparticles (SLNs) of altretamine (ALT) by the hot homogenization and ultrasonication method. The study was conducted using the Box-Behnken design (BBD), with a 3(3) design and a total of 17 experimental runs, performed in combination with response surface methodology (RSM). The SLNs were evaluated for mean particle size, entrapment efficiency, and drug-loading. The optimized formulation, with a desirability factor of 0.92, was selected and characterized. In vitro release studies showed a biphasic release pattern from the SLNs for up to 24 h. The results of % EE (93.21 ± 1.5), %DL (1.15 ± 0.6), and mean diameter of (100.6 ± 2.1) nm, were very close to the predicted values.

  9. Deep-subwavelength light routing in nanowire-loaded surface plasmon polariton waveguides: an alternative to the hybrid guiding scheme

    International Nuclear Information System (INIS)

    Bian, Yusheng; Gong, Qihuang

    2013-01-01

    Nanowire-loaded surface plasmon polariton waveguide is an extremely simple structure that can be naturally formed by directly dropping a dielectric cylinder onto a metallic substrate. However, despite the substantial emphasis devoted to its hybrid plasmonic counterparts, this waveguiding structure has been paid little attention to so far. Here in this paper, through comprehensive numerical analysis, we reveal that such a configuration can be leveraged to achieve deep-subwavelength field confinement with mode area more than one order of magnitude smaller than that of the conventional hybrid waveguide, while maintaining a moderate attenuation with propagation distance over tens of microns. Two-dimensional parameter mapping concerning physical dimension, shape and material of the nanowire as well as the refractive index of the cladding has disclosed the wide-range existence nature of this plasmonic mode and the feasibility to further balance its confinement and loss. (paper)

  10. Advanced surface chemical analysis of continuously manufactured drug loaded composite pellets.

    Science.gov (United States)

    Hossain, Akter; Nandi, Uttom; Fule, Ritesh; Nokhodchi, Ali; Maniruzzaman, Mohammed

    2017-04-15

    The aim of the present study was to develop and characterise polymeric composite pellets by means of continuous melt extrusion techniques. Powder blends of a steroid hormone (SH) as a model drug and either ethyl cellulose (EC N10 and EC P7 grades) or hydroxypropyl methylcellulose (HPMC AS grade) as polymeric carrier were extruded using a Pharma 11mm twin screw extruder in a continuous mode of operation to manufacture extruded composite pellets of 1mm length. Molecular modelling study using commercial Gaussian 09 software outlined a possible drug-polymer interaction in the molecular level to develop solid dispersions of the drug in the pellets. Solid-state analysis conducted via a differential scanning calorimetry (DSC), hot stage microscopy (HSM) and X-ray powder diffraction (XRPD) analyses revealed the amorphous state of the drug in the polymer matrices. Surface analysis using SEM/energy dispersive X-ray (EDX) of the produced pellets arguably showed a homogenous distribution of the C and O atoms in the pellet matrices. Moreover, advanced chemical surface analysis conducted via atomic force microscopy (AFM) showed a homogenous phase system having the drug molecule dispersed onto the amorphous matrices while Raman mapping confirmed the homogenous single-phase drug distribution in the manufactured composite pellets. Such composite pellets are expected to deliver multidisciplinary applications in drug delivery and medical sciences by e.g. modifying drug solubility/dissolutions or stabilizing the unstable drug (e.g. hormone, protein) in the composite network. Copyright © 2016. Published by Elsevier Inc.

  11. Influences of the variation in inflow to East Asia on surface ozone over Japan during 1996–2005

    Directory of Open Access Journals (Sweden)

    S. Chatani

    2011-08-01

    Full Text Available Air quality simulations in which the global chemical transport model CHASER and the regional chemical transport model WRF/chem are coupled have been developed to consider the dynamic transport of chemical species across the boundaries of the domain of the regional chemical transport model. The simulation captures the overall seasonal variations of surface ozone, but overestimates its concentration over Japanese populated areas by approximately 20 ppb from summer to early winter. It is deduced that ozone formation around Northeast China and Japan in summer is overestimated in the simulation. On the other hand, the simulation well reproduces the interannual variability and the long-term trend of observed surface ozone over Japan. Sensitivity experiments have been performed to investigate the influence of the variation in inflow to East Asia on the interannual variability and the long-term trend of surface ozone over Japan during 1996–2005. The inflow defined in this paper includes the recirculation of species with sources within the East Asian region as well as the transport of species with sources out of the East Asian region. Results of sensitivity experiments suggest that inflow to East Asia accounts for approximately 30 % of the increasing trend of surface ozone, whereas it has much less influence on the interannual variability of observed surface ozone compared to meteorological processes within East Asia.

  12. Spatial and Seasonal Variations of Heavy Metal Loads in Uyo Urban Drainage Stream under PS and NPS Pollution

    Directory of Open Access Journals (Sweden)

    O. E. Essien

    2012-12-01

    Full Text Available The concentration of heavy metals (HM in the 4km urban drainage stream in Uyo was studied using grab and composite sampling of water from six stations on the stream, and analyzed by a multipurpose atomic absorption spectrophotometer. The data were statistically analyzed using SPSS version 17 software arid correlated between stations and among samples. HM contamination was evaluated with the coefficient and rate of dispersion between stations and the Normalized Scatter Coefficient (NSC. The seasonal distribution of metal pollution varied individually amongst metals at stations. The Fe and Pb concentrations exceeded the safe drinking water standard, rendering the water quality not acceptable for drinking; however, the quality was within the safe limit for crop production along the river bank. The relative.dominance of heavy metals followed a different sequence in upstream leachate effluent from all downstream stations. The NSC in dry-wet season was higher than in wet season, and was in the order: Fe>Cu>Zn>Pb, showing that large but variable concentration of Fe from PS and NPS contaminated the stream at faster rate in the wet season while Pb contaminated at nearly constant rate. However, in the dry season, Fe and Pb depleted at downstream at rates far higher than Zn as Cu was increasing. Fe and Pb could be good pollution monitor for total maximum daily load (TMDL pollution monitoring programme.

  13. The assessment of material-handling strategies in dealing with sudden loading: the effect of uneven ground surface on trunk biomechanical responses.

    Science.gov (United States)

    Zhou, Jie; Ning, Xiaopeng; Nimbarte, Ashish D; Dai, Fei

    2015-01-01

    As a major risk factor of low back injury, sudden loading often occurs when performing manual material-handling tasks on uneven ground surfaces. Therefore, the purpose of the current study was to investigate the effects of a laterally slanted ground on trunk biomechanical responses during sudden loading events. Thirteen male subjects were subjected to suddenly released loads of 3.4 and 6.8 kg, while standing on a laterally slanted ground of 0°, 15° and 30°. The results showed that 8.3% and 5.6% larger peak L5/S1 joint compression forces were generated in the 30° condition compared with the 0° and 15° conditions, respectively. The increase of L5/S1 joint moment in the 30° condition was 8.5% and 5.0% greater than the 0° and 15° conditions, respectively. Findings of this study suggest that standing on a laterally slanted ground could increase mechanical loading on the spine when experiencing sudden loading. Practitioner Summary: Sudden loading is closely related to occupational low back injuries. The results of this study showed that the increase of slanted ground angle and magnitude of load significantly increase the mechanical loading on the spine during sudden loading. Therefore, both of these two components should be controlled in task design.

  14. Measuring variation of indoor radon concentration using bare nuclear tracks detectors, scintillation counters and surface barrier detectors

    International Nuclear Information System (INIS)

    Ishak, I.; Mahat, R.H.; Amin, Y.M.

    1996-01-01

    Bare LRI 15 nuclear track detectors , scintillators counter and surface barrier detectors were used to measured the indoor radon concentration in various location within two rooms. Spatial variation of the radon concentration is caused by positioning of the door, windows, furniture, cracks in the building and also distances from floor, wall and ceiling. It is found that the change in temperature are causing radon concentration to increase at certain time of the day

  15. Seasonal and Spatial Variation of Surface Urban Heat Island Intensity in a Small Urban Agglomerate in Brazil

    Directory of Open Access Journals (Sweden)

    Elis Dener Lima Alves

    2016-12-01

    Full Text Available In recent years, SUHIs (surface urban heat islands have been greatly emphasized in urban climate studies, since it is one of the climate phenomena most influenced by human action. In this study, temporal and spatial variations of SUHIs in the cities of Ceres and Rialma (Brazil were investigated; satellite Landsat 8 TIRS/OLI images from 2013 to 2016 were used for this purpose. The results showed that in all seasons, two relationships were observed, one positive and one negative. An N D V I (Normalized Difference Vegetation Index of 0.2 is the divider of this relationship: up to this value, the relationship is positive, that is, the higher the N D V I value, the higher the surface temperature, while the relationship is negative at an N D V I greater than 0.2. There was high seasonal variation in the SUHIs, with the highest intensities recorded in the spring and summer (±12 °C, and the lowest in the winter. These temporal variations were attributed to the annual cycle of precipitation, which directly involves the robustness of the Cerrado vegetation. SUHIs occupied, on average, an area three times larger than the area of SUCIs (surface urban cool islands. The highest values of SUCIs were observed in water bodies and in valley bottoms. Overall, SUHIs showed high intensities; however, a more intense core area, such as in large cities, was not observed.

  16. Effect of type and loading of surface-modifying agent on mechanical properties of modified geothermal scale powder/stereolithography polymer composite

    Science.gov (United States)

    Tilendo, A. C.; Pajarito, B. B.

    2017-05-01

    This study investigated the effect of stearic acid (SA), glycerol monostearate (GMS) and 3-trimethoxysilylpropyl methacrylate (TSPM) at varied loadings on the hardness and flexural properties of modified geothermal scale powder (GSP)/stereolithography (SLA) polymer composite. TSPM-modified GSP/SLA composite has the highest value of hardness due to increased filler dispersion and crystallinity. Hardness of GSP/SLA composite increases with loading of surface-modifying agent due to increase filler dispersion. Pronounced effect of surface modification to flexural modulus is observed. While low loading of SA and GMS leads to reduction of flexural modulus, increasing loading enhances the said property. Further increase of SA deteriorates the property. TSPM-modified GSP enhances the modulus due to increased crystalline phase of the system owing to TSPM copolymerization. Likewise, addition of SA and GMS increases flexural strength due to efficient reduction of filler agglomerates. However, unreacted TSPM produces weak interfaces and poor adhesion between GSP and SLA matrix.

  17. Structural evolution of tungsten surface exposed to sequential low-energy helium ion irradiation and transient heat loading

    Directory of Open Access Journals (Sweden)

    G. Sinclair

    2017-08-01

    Full Text Available Structural damage due to high flux particle irradiation can result in significant changes to the thermal strength of the plasma facing component surface (PFC during off-normal events in a tokamak. Low-energy He+ ion irradiation of tungsten (W, which is currently the leading candidate material for future PFCs, can result in the development of a fiber form nanostructure, known as “fuzz”. In the current study, mirror-finished W foils were exposed to 100eV He+ ion irradiation at a fluence of 2.6 ×1024ionsm−2 and a temperature of 1200K. Then, samples were exposed to two different types of pulsed heat loading meant to replicate type-I edge-localized mode (ELM heating at varying energy densities and base temperatures. Millisecond (ms laser exposure done at 1200K revealed a reduction in fuzz density with increasing energy density due to the conglomeration and local melting of W fibers. At higher energy densities (∼ 1.5MJm−2, RT exposures resulted in surface cracking, while 1200K exposures resulted in surface roughening, demonstrating the role of base temperature on the crack formation in W. Electron beam heating presented similar trends in surface morphology evolution; a higher penetration depth led to reduced melt motion and plasticity. In situ mass loss measurements obtained via a quartz crystal microbalance (QCM found an exponential increase in particle emission for RT exposures, while the prevalence of melting from 1200K exposures yielded no observable trend.

  18. Nano-Ag-loaded hydroxyapatite coatings on titanium surfaces by electrochemical deposition.

    Science.gov (United States)

    Lu, Xiong; Zhang, Bailin; Wang, Yingbo; Zhou, Xianli; Weng, Jie; Qu, Shuxin; Feng, Bo; Watari, Fumio; Ding, Yonghui; Leng, Yang

    2011-04-06

    Hydroxyapatite (HA) coatings on titanium (Ti) substrates have attracted much attention owing to the combination of good mechanical properties of Ti and superior biocompatibility of HA. Incorporating silver (Ag) into HA coatings is an effective method to impart the coatings with antibacterial properties. However, the uniform distribution of Ag is still a challenge and Ag particles in the coatings are easy to agglomerate, which in turn affects the applications of the coatings. In this study, we employed pulsed electrochemical deposition to co-deposit HA and Ag simultaneously, which realized the uniform distribution of Ag particles in the coatings. This method was based on the use of a well-designed electrolyte containing Ag ions, calcium ions and l-cysteine, in which cysteine acted as the coordination agent to stabilize Ag ions. The antibacterial and cell culture tests were used to evaluate the antibacterial properties and biocompatibility of HA/Ag composite coatings, respectively. The results indicated the as-prepared coatings had good antibacterial properties and biocompatibility. However, an appropriate silver content should be chosen to balance the biocompatibility and antibacterial properties. Heat treatments promoted the adhesive strength and enhanced the biocompatibility without sacrificing the antibacterial properties of the HA/Ag coatings. In summary, this study provided an alternative method to prepare bioactive surfaces with bactericidal ability for biomedical devices.

  19. Highly sensitive surface enhanced Raman scattering substrates based on filter paper loaded with plasmonic nanostructures.

    Science.gov (United States)

    Lee, Chang H; Hankus, Mikella E; Tian, Limei; Pellegrino, Paul M; Singamaneni, Srikanth

    2011-12-01

    We report a novel surface enhanced Raman scattering (SERS) substrate platform based on a common filter paper adsorbed with plasmonic nanostructures that overcomes many of the challenges associated with existing SERS substrates. The paper-based design results in a substrate that combines all of the advantages of conventional rigid and planar SERS substrates in a dynamic flexible scaffolding format. In this paper, we discuss the fabrication, physical characterization, and SERS activity of our novel substrates using nonresonant analytes. The SERS substrate was found to be highly sensitive, robust, and amiable to several different environments and target analytes. It is also cost-efficient and demonstrates high sample collection efficiency and does not require complex fabrication methodologies. The paper substrate has high sensitivity (0.5 nM trans-1,2-bis(4-pyridyl)ethene (BPE)) and excellent reproducibility (~15% relative standard deviation (RSD)). The paper substrates demonstrated here establish a novel platform for integrating SERS with already existing analytical techniques such as chromatography and microfluidics, imparting chemical specificity to these techniques.

  20. Sensitivity-Based Modeling of Evaluating Surface Runoff and Sediment Load using Digital and Analog Mechanisms

    Directory of Open Access Journals (Sweden)

    Olotu Yahaya

    2014-07-01

    Full Text Available Analyses of runoff- sediment measurement and evaluation using automated and convectional runoff-meters was carried out at Meteorological and Hydrological Station of Auchi Polytechnic, Auchi using two runoff plots (ABCDa and EFGHm of area 2m 2 each, depth 0.26 m and driven into the soil to the depth of 0.13m. Runoff depths and intensities were measured from each of the positioned runoff plot. Automated runoff-meter has a measuring accuracy of ±0.001l/±0.025 mm and rainfall depth-intensity was measured using tipping-bucket rainguage during the period of 14-month of experimentation. Minimum and maximum rainfall depths of 1.2 and 190.3 mm correspond to measured runoff depths (MRo of 0.0 mm for both measurement approaches and 60.4 mm and 48.9 mm respectively. Automated runoffmeter provides precise, accurate and instantaneous result over the convectional measurement of surface runoff. Runoff measuring accuracy for automated runoff-meter from the plot (ABCDa produces R 2 = 0.99; while R 2 = 0.96 for manual evaluation in plot (EFGHm. WEPP and SWAT models were used to simulate the obtained hydrological variables from the applied measurement mechanisms. The outputs of sensitivity simulation analysis indicate that data from automated measuring systems gives a better modelling index and such could be used for running robust runoff-sediment predictive modelling technique under different reservoir sedimentation and water management scenarios.

  1. The Role of Meteorology and Surface Condition to Multi-Decadal Variations of Dust Emission in Sahara and Sahel

    Science.gov (United States)

    Kim, D.; Chin, M.; Diehl, T. L.; Bian, H.; Brown, M. E.; Remer, L. A.; Stockwell, W. R.

    2014-12-01

    North Africa is the world's largest dust source region influencing regional and global climate, human health, and even the local economy. However North Africa as a dust source is not uniform but it consists of the arid region (Sahara) and the semi-arid region (Sahel) with emission rates depending on meteorological and surface conditions. Several recent studies have shown that dust from North Africa seems to have a decreasing trend in the past three decades. The goal of this study is to better understand the controlling factors that determine the change of dust in North Africa using observational data and model simulations. First we analyze surface bareness conditions determined from a long-term satellite observed Normalized Difference Vegetation Index for 1980-2008. Then we examine the key meteorological variables of precipitation and surface winds. Modeling experiments were conducted using the NASA Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, which has been recently updated with a dynamic dust source function. Using the method we separate the dust originating from the Sahel from that of the Sahara desert. We find that the surface wind speed is the most dominant factor affecting Sahelian dust emission while vegetation has a modulating effect. We will show regional differences in meteorological variables, surface conditions, dust emission, and dust distribution and address the relationships among meteorology, surface conditions, and dust emission/loading in the past three decades (1980-2008).

  2. Impact of ambient air temperature and heat load variation on the performance of air-cooled heat exchangers in propane cycles in LNG plants – Analytical approach

    International Nuclear Information System (INIS)

    Fahmy, M.F.M.; Nabih, H.I.

    2016-01-01

    Highlights: • An analytical method regulated the air flow rate in an air-cooled heat exchanger. • Performance of an ACHE in a propane cycle in an LNG plant was evaluated. • Summer inlet air temperature had higher impact on ACHE air flow rate requirement. - Abstract: An analytical method is presented to evaluate the air flow rate required in an air-cooled heat exchanger used in a propane pre-cooling cycle operating in an LNG (liquefied natural gas) plant. With variable ambient air inlet temperature, the air flow rate is to be increased or decreased so as to assure and maintain good performance of the operating air-cooled heat exchanger at the designed parameters and specifications. This analytical approach accounts for the variations in both heat load and ambient air inlet temperature. The ambient air inlet temperature is modeled analytically by simplified periodic relations. Thus, a complete analytical method is described so as to manage the problem of determining and accordingly regulate, either manually or automatically, the flow rate of air across the finned tubes of the air-cooled heat exchanger and thus, controls the process fluid outlet temperature required for the air-cooled heat exchangers for both cases of constant and varying heat loads and ambient air inlet temperatures. Numerical results are obtained showing the performance of the air-cooled heat exchanger of a propane cycle which cools both NG (natural gas) and MR (mixed refrigerant) streams in the LNG plant located at Damietta, Egypt. The inlet air temperature variation in the summer time has a considerable effect on the required air mass flow rate, while its influence becomes relatively less pronounced in winter.

  3. Impact of Surface Soil Moisture Variations on Radar Altimetry Echoes at Ku and Ka Bands in Semi-Arid Areas

    Directory of Open Access Journals (Sweden)

    Christophe Fatras

    2018-04-01

    Full Text Available Radar altimetry provides information on the topography of the Earth surface. It is commonly used for the monitoring not only sea surface height but also ice sheets topography and inland water levels. The radar altimetry backscattering coefficient, which depends on surface roughness and water content, can be related to surface properties such as surface soil moisture content. In this study, the influence of surface soil moisture on the radar altimetry echo and backscattering coefficient is analyzed over semi-arid areas. A semi-empirical model of the soil’s complex dielectric permittivity that takes into account that small-scale roughness and large-scale topography was developed to simulate the radar echoes. It was validated using waveforms acquired at Ku and Ka-bands by ENVISAT RA-2 and SARAL AltiKa respectively over several sites in Mali. Correlation coefficients ranging from 0.66 to 0.94 at Ku-band and from 0.27 to 0.96 at Ka-band were found. The increase in surface soil moisture from 0.02 to 0.4 (i.e., the typical range of variations in semi-arid areas increase the backscattering from 10 to 15 dB between the core of the dry and the maximum of the rainy seasons.

  4. Analysis of the Intra-City Variation of Urban Heat Island and its Relation to Land Surface/cover Parameters

    Science.gov (United States)

    Gerçek, D.; Güven, İ. T.; Oktay, İ. Ç.

    2016-06-01

    Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI) effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI) effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI), imperviousness (NDISI), albedo, solar insolation, Sky View Factor (SVF), building envelope

  5. ANALYSIS OF THE INTRA-CITY VARIATION OF URBAN HEAT ISLAND AND ITS RELATION TO LAND SURFACE/COVER PARAMETERS

    Directory of Open Access Journals (Sweden)

    D. Gerçek

    2016-06-01

    Full Text Available Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI, imperviousness (NDISI, albedo, solar insolation, Sky View Factor (SVF, building

  6. Chemical loading into surface water along a hydrological, biogeochemical, and land use gradient: A holistic watershed approach

    Science.gov (United States)

    Barber, L.B.; Murphy, S.F.; Verplanck, P.L.; Sandstrom, M.W.; Taylor, Howard E.; Furlong, E.T.

    2006-01-01

    Identifying the sources and impacts of organic and inorganic contaminants at the watershed scale is a complex challenge because of the multitude of processes occurring in time and space. Investigation of geochemical transformations requires a systematic evaluation of hydrologic, landscape, and anthropogenic factors. The 1160 km2 Boulder Creek Watershed in the Colorado Front Range encompasses a gradient of geology, ecotypes, climate, and urbanization. Streamflow originates primarily as snowmelt and shows substantial annual variation. Water samples were collected along a 70-km transect during spring-runoff and base-flow conditions, and analyzed for major elements, trace elements, bulk organics, organic wastewater contaminants (OWCs), and pesticides. Major-element and trace-element concentrations were low in the headwaters, increased through the urban corridor, and had a step increase downstream from the first major wastewater treatment plant (WWTP). Boron, gadolinium, and lithium were useful inorganic tracers of anthropogenic inputs. Effluent from the WWTP accounted for as much as 75% of the flow in Boulder Creek and was the largest chemical input. Under both hydrological conditions, OWCs and pesticides were detected in Boulder Creek downstream from the WWTP outfall as well as in the headwater region, and loads of anthropogenic-derived contaminants increased as basin population density increased. This report documents a suite of potential endocrine-disrupting chemicals in a reach of stream with native fish populations showing indication of endocrine disruption.

  7. Quantitative estimation of Holocene surface salinity variation in the Black Sea using dinoflagellate cyst process length

    DEFF Research Database (Denmark)

    Mertens, Kenneth Neil; Bradley, Lee R.; Takano, Yoshihito

    2012-01-01

    this calibration to make a regional reconstruction of paleosalinity in the Black Sea, calculated by averaging out process length variation observed at four core sites from the Black Sea with high sedimentation rates and dated by multiple mollusk shell ages. Results show a very gradual change of salinity from ∼14...

  8. On a free-surface problem with moving contact line: From variational principles to stable numerical approximations

    Science.gov (United States)

    Fumagalli, Ivan; Parolini, Nicola; Verani, Marco

    2018-02-01

    We analyze a free-surface problem described by time-dependent Navier-Stokes equations. Surface tension, capillary effects and wall friction are taken into account in the evolution of the system, influencing the motion of the contact line - where the free surface hits the wall - and of the dynamics of the contact angle. The differential equations governing the phenomenon are first derived from the variational principle of minimum reduced dissipation, and then discretized by means of the ALE approach. The numerical properties of the resulting scheme are investigated, drawing a parallel with the physical properties holding at the continuous level. Some instability issues are addressed in detail, in the case of an explicit treatment of the geometry, and novel additional terms are introduced in the discrete formulation in order to damp the instabilities. Numerical tests assess the suitability of the approach, the influence of the parameters, and the effectiveness of the new stabilizing terms.

  9. Bacterial community diversity and variation in spray water sources and the tomato fruit surface

    Directory of Open Access Journals (Sweden)

    Ottesen Andrea R

    2011-04-01

    Full Text Available Abstract Background Tomato (Solanum lycopersicum consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. Results The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Conclusions Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an

  10. Influence of the surface permeability on the GRACE water mass variations. Case of the Lake Chad basin.

    Science.gov (United States)

    Lopez, T.; Ramillien, G.; Antoine, R.; Darrozes, J.; Rabinowicz, M.

    2017-12-01

    Since its launch in 2002, the Gravity Recovery And Climate Experiment (GRACE) has been measured the tiny variations of the gravity field due to redistributions of water mass in the surface envelops of Earth. At a spatial resolution of 400 km, these satellite data offer a unique perspective to understand the evolution of continental water storage at regional and global scales, and therefore they enable the monitoring of the hydrological systems such as river basins. It is well known that seasonal cycle, droughts, vegetation and human extractions are the main contributors of the hydrology signals sensed by GRACE. However, the coupling between land surface and the atmosphere is important in semi-arid and arid regions, in particular in West Africa [1]. We propose to quantify the surface water fluxes in the Lake Chad region by using the 10-day water mass solutions of the GRACE mission in the context of the regular West African monsoon. Alternation of the evaporation/condensation cycles during the recent period are interpreted in terms of surface vertical permeability changes that control the thermal evolution in this region [2]. GRACE solutions reveal an interannual increase of surface water mass at the beginning of the dry seasons, especially between 2005 and 2008. We propose that this gain of surface water mass is caused by a seasonal cycle of clay fracturing that controls the evaporation/condensation cycle. [1] Koster et al. (2004). Science, 305, 1138-1140. [2] Lopez et al. (2016). Surv. Geophys., 37 (2), 471-502.

  11. The investigation of spatiotemporal variations of land surface temperature based on land use changes using NDVI in southwest of Iran

    Science.gov (United States)

    Fathizad, Hassan; Tazeh, Mahdi; Kalantari, Saeideh; Shojaei, Saeed

    2017-10-01

    Land use changes can bring about changes in land surface temperature (LST) which is influenced by climatic conditions and physical characteristics of the land surface. In this study, spatiotemporal variations of land surface temperature have been investigated in the desert area of Dasht-e-Abbas, Ilam, based on a variety of land use changes. The investigated periods for the study include 1990, 2000 and 2010 using Landsat image data. First, in mapping land use we used the Fuzzy ARTMAP Neural Network Classification method followed by determination of the NDVI Index to estimate land surface temperature. The results show an increase in LST in areas where degradation, land use and land cover changes have occurred. In 1990, 2000 and 2010, the average land surface temperature of the Fair Rangelands was 26.72 °C, 30.06 °C and 30.95 °C, respectively. This rangeland has been reduced by about 5%. For poor rangelands, the average LSTs were 26.95, 32.83 and 34.49 Cº, respectively which had a 18% reduction. In 1990, 2000 and 2010, the average land surface temperatures of agricultural lands were 24.31 °C, 27.87 °C and 28.61 °C, respectively which has been an increasing trend. The reason can be attributed to changes in cropping patterns of the study area.

  12. Influence of ozone precursors and particulate matter on the variation of surface ozone at an urban site of Delhi, India

    Directory of Open Access Journals (Sweden)

    Ashima Sharma

    2016-03-01

    Full Text Available Continuous measurements of surface O3 and its precursors (NO, NO2, CO, CH4 and NMHCs at an urban site of Delhi, India during January 2012 to December 2013 are presented. In the present study, the annual average mixing ratios of surface O3, NO, NO2, CO, CH4 and NMHC were 30 ± 6 ppb, 24 ± 6 ppb, 15 ± 4 ppb, 1.5 ± 0.4 ppm, 2.4 ± 0.4 ppm and 0.4 ± 0.1 ppm, respectively. The maximum average mixing ratios of surface O3, NO and NO2 were observed during the summer, whereas, the minimum average mixing ratios of ambient NO and NO2 were during monsoon seasons. The surface O3, NO and NO2 have shown the prominent diurnal variations during all the seasons at the observational site of Delhi. The result reveals that the surface O3 was negatively correlated with NOx and CO during the study. The linear scatter plot analysis shows that the PM2.5 and PM10 present in the ambient air of Delhi influence the production of surface O3 at observational site.

  13. Study of inter-annual variations in surface melting over Amery Ice ...

    Indian Academy of Sciences (India)

    Lambert Glacier ... Thus, monitoring surface melt conditions is critical for evaluating the stability of Antarctic ice shelves (Kunz and. Long 2006). Davis. Station. Site-1. Lambert. Glacier ..... P A, Jones J and Bitz C 2006 Antarctic temperature over.

  14. A Remote Sensing Analysis on the Spatiotemporal Variation of Land Surface Albedo and Emissivity in South Florida: An Implication for Surface-Atmosphere Energy and Water Exchange

    Science.gov (United States)

    Kandel, H. P.; Melesse, A. M.

    2016-12-01

    Land use /land cover has wide range of impacts from surface energy budget to radiative forcing of climate change. This study aims to analyze the variation in two radiative properties, albedo and emissivity in South Florida landscape to investigate how radially distinct surfaces lead to a energy and moisture contrast on the near-surface atmosphere and eventually to surface-induced climate. Maps of land surface albedo and emissivity were prepared using algorithms that convert narrow-band spectral reflectance to total short-wave albedo, and vegetation index to emissivity from Landsat -5 TM images of several different summer dates. A comparative analysis was made using the zonal statistics in ArcGIS. Relatively higher albedos were found over cultivated and developed lands (0.17 - 0.21) than in forests and herbaceous wetland (0.09 - 0.16). The emissivities, on the other hand, are lower for developed and drained lands. Average albedo exhibits a slight increase whereas emissivity is found to be decreasing through time. Urban areas showing higher albedos, a unique occurrence in this landscape, store less short-wave radiation, however, their lower emissivities points to increased storage of long-wave radiation. The results imply that the emissivity perhaps play a dominant role in heat island development and initiation of local circulation in urbanized South Florida.

  15. KIR content genotypes associate with carriage of hepatitis B surface antigen, e antigen and HBV viral load in Gambians.

    Directory of Open Access Journals (Sweden)

    Louis-Marie Yindom

    Full Text Available Hepatocellular carcinoma (HCC causes over 800,000 deaths worldwide annually, mainly in low income countries, and incidence is rising rapidly in the developed world with the spread of hepatitis B (HBV and C (HCV viruses. Natural Killer (NK cells protect against viral infections and tumours by killing abnormal cells recognised by Killer-cell Immunoglobulin-like Receptors (KIR. Thus genes and haplotypes encoding these receptors may be important in determining both outcome of initial hepatitis infection and subsequent chronic liver disease and tumour formation. HBV is highly prevalent in The Gambia and the commonest cause of liver disease. The Gambia Liver Cancer Study was a matched case-control study conducted between September 1997 and January 2001 where cases with liver disease were identified in three tertiary referral hospitals and matched with out-patient controls with no clinical evidence of liver disease.We typed 15 KIR genes using the polymerase chain reaction with sequence specific primers (PCR-SSP in 279 adult Gambians, 136 with liver disease (HCC or Cirrhosis and 143 matched controls. We investigated effects of KIR genotypes and haplotypes on HBV infection and associations with cirrhosis and HCC.Homozygosity for KIR group A gene-content haplotype was associated with HBsAg carriage (OR 3.7, 95% CI 1.4-10.0 whilst telomeric A genotype (t-AA was associated with reduced risk of e antigenaemia (OR 0.2, 95% CI 0.0-0.6 and lower viral loads (mean log viral load 5.2 vs. 6.9, pc = 0.022. One novel telomeric B genotype (t-ABx2 containing KIR3DS1 (which is rare in West Africa was also linked to e antigenaemia (OR 8.8, 95% CI 1.3-60.5. There were no associations with cirrhosis or HCC.Certain KIR profiles may promote clearance of hepatitis B surface antigen whilst others predispose to e antigen carriage and high viral load. Larger studies are necessary to quantify the effects of individual KIR genes, haplotypes and KIR/HLA combinations on long

  16. KIR content genotypes associate with carriage of hepatitis B surface antigen, e antigen and HBV viral load in Gambians.

    Science.gov (United States)

    Yindom, Louis-Marie; Mendy, Maimuna; Bodimeade, Christopher; Chambion, Caroline; Aka, Peter; Whittle, Hilton C; Rowland-Jones, Sarah L; Walton, Robert

    2017-01-01

    Hepatocellular carcinoma (HCC) causes over 800,000 deaths worldwide annually, mainly in low income countries, and incidence is rising rapidly in the developed world with the spread of hepatitis B (HBV) and C (HCV) viruses. Natural Killer (NK) cells protect against viral infections and tumours by killing abnormal cells recognised by Killer-cell Immunoglobulin-like Receptors (KIR). Thus genes and haplotypes encoding these receptors may be important in determining both outcome of initial hepatitis infection and subsequent chronic liver disease and tumour formation. HBV is highly prevalent in The Gambia and the commonest cause of liver disease. The Gambia Liver Cancer Study was a matched case-control study conducted between September 1997 and January 2001 where cases with liver disease were identified in three tertiary referral hospitals and matched with out-patient controls with no clinical evidence of liver disease. We typed 15 KIR genes using the polymerase chain reaction with sequence specific primers (PCR-SSP) in 279 adult Gambians, 136 with liver disease (HCC or Cirrhosis) and 143 matched controls. We investigated effects of KIR genotypes and haplotypes on HBV infection and associations with cirrhosis and HCC. Homozygosity for KIR group A gene-content haplotype was associated with HBsAg carriage (OR 3.7, 95% CI 1.4-10.0) whilst telomeric A genotype (t-AA) was associated with reduced risk of e antigenaemia (OR 0.2, 95% CI 0.0-0.6) and lower viral loads (mean log viral load 5.2 vs. 6.9, pc = 0.022). One novel telomeric B genotype (t-ABx2) containing KIR3DS1 (which is rare in West Africa) was also linked to e antigenaemia (OR 8.8, 95% CI 1.3-60.5). There were no associations with cirrhosis or HCC. Certain KIR profiles may promote clearance of hepatitis B surface antigen whilst others predispose to e antigen carriage and high viral load. Larger studies are necessary to quantify the effects of individual KIR genes, haplotypes and KIR/HLA combinations on long

  17. [Temperature variation at the external root surface during Nd: YAG laser irradiation in the root canal in vitro].

    Science.gov (United States)

    Yuan-Gao, Li; Xiao, Wang; Kexian, Xie; Dan, Liu

    2014-10-01

    To assess the temperature variation of the root surface using Nd: YAG laser irradiation in the root canal with different power and to evaluate the safety of laser application on the periodontal region. Thirty extracted human teeth with single-roots were collected. The teeth were cross-sectioned in the cervical portion, standardizing the roots at a 12-mm length. The roots were used as specimen. The roots were radiographed in the buccal-lingual direction to measure the thickness of the proximal walls, by means of a digital radiographic system. The specimens were divided into three groups according to the laser potency (1.5, 3.0, and 4.5 W). Each group was subdivided into two subgroups according to laser frequency (15 and 30 Hz). With the Nd: YAG laser irradiation for 20 s, the temperature variation of the root surface was monitored by thermocouples located at different parts of the root external wall and recorded by digital thermometers. The groups irradiated with 4.5 W presented the greatest temperature variation (above 10°C), followed by 3.0 and 1.5 W. The temperatures were statistically different (P 0.05). The apical half of the root presented statistically higher temperature rises than the cervical half of the root (P laser power, irradiation time, and the thickness of dentin. Application of Nd: YAG laser in the root at 1.5 W for 20 s can safely be used in endodontic treatment.

  18. ANALYSIS OF ROAD SURFACE TEMPERATURE VARIATION ALONG THE ROAD SEGMENTATION USING MOBILE THERMAL SENSOR

    OpenAIRE

    Dukgeun Yun; Jaehong Park

    2016-01-01

    According to the road accidents statistics of Korea, 33% of fatalities occurred in winter. As many factors can be the causes of the accidents in winter season, road freezing is the most important factor among them. Even though the road surface temperature is more important than air temperature, generally the drivers and road manager get the air temperature from the weather forecast. If a road manager has information or can predict the road surface condition or temperature, the accidents relat...

  19. Revealing textural variations at the groundwater-surface water interface using induced polarisation techniques

    Science.gov (United States)

    McLachlan, P.; Binley, A. M.; Chambers, J. E.

    2016-12-01

    The groundwater-surface water (GW-SW) interface actively governs the transfer of water, nutrients and contaminants between groundwater systems and surface water environments. It is capable of mitigating environmental pollution by attenuating and transforming contaminants transported by groundwater discharging to the surface or by surface water recharging to the subsurface. The ability of the GW-SW interface to mitigate pollution is linked to its hydrological and physiochemical properties, the presence of grain surfaces, and its consequent ability to host diverse microbial populations. Despite its importance, characterising the GW-SW interface remains a challenge as traditional methods are often intrusive, environmentally damaging or labour intensive and so they often provide spatially sparse, or spatially restricted, information. There is therefore a requirement for methods which can provide information about the GW-SW interface at high spatial resolution and over large areas. In recent years there has been increased interest in using induced polarisation in field based exploration to characterise grain surface properties of unconsolidated geological materials. Induced polarisation may offer the potential to interrogate textural properties of the GW-SW interface, such as cation exchange and grain surface area which are important for determining the biogeochemical properties of the subsurface. Here we demonstrate the ability of induced polarisation measurements to reveal contrasts in the textural properties of two sites on a 200 m river meander (River Leith, Cumbria, UK). Previous work has revealed that both sites are distinctive in terms of their hydrology, fluvial deposits and biogeochemistry. We present in-stream induced polarisation measurements in addition to lab based measurements of induced polarisation, cation exchange capacity, grain size distribution and surface area on samples obtained from drilling.

  20. Immediate and early loading of Straumann implants with a chemically modified surface (SLActive) in the posterior mandible and maxilla: 1-year results from a prospective multicenter study.

    Science.gov (United States)

    Ganeles, Jeffrey; Zöllner, Axel; Jackowski, Jochen; ten Bruggenkate, Christiaan; Beagle, Jay; Guerra, Fernando

    2008-11-01

    Immediate and early loading of implants can simplify treatment and increase patient satisfaction. This 3-year randomized-controlled trial will therefore evaluate survival rates and bone-level changes with immediately and early loaded Straumann implants with the SLActive surface. Partially edentulous patients >or=18 years of age were enrolled. Patients received a temporary restoration (single crown or two to four unit fixed partial denture) out of occlusal contact either immediately (immediate loading) or 28-34 days later (early loading group), with permanent restorations placed 20-23 weeks after surgery. The primary endpoint was change in crestal bone level from baseline (implant placement) to 12 months; the secondary variables were implant survival and success rates. A total of 383 implants (197 immediate and 186 early) were placed in 266 patients; 41.8% were placed in type III and IV bone. The mean patient age was 46.3+/-12.8 years. Four implants failed in the immediate loading group and six in the early loading group, giving implant survival rates of 98% and 97%, respectively (P=NS). There were no implant failures in type IV bone. The overall mean bone level change from baseline to 12 months was 0.77+/-0.93 mm (0.90+/-0.90 and 0.63+/-0.95 mm in the immediate and early groups, respectively; PStraumann implants with the SLActive surface are safe and predictable when used in immediate and early loading procedures. Even in poor-quality bone, survival rates were comparable with those from conventional or delayed loading. The mean bone-level change was not deemed to be clinically significant and compared well with the typical bone resorption observed in conventional implant loading.

  1. Diffusion Filters for Variational Data Assimilation of Sea Surface Temperature in an Intermediate Climate Model

    Science.gov (United States)

    2015-01-01

    state estimation and forecast in real applica- tions using general circulation models (GCMs). In addition, other spatial multiscale variational analysis...Journal of Geophysical Research C: Oceans, vol. 102, no. 3, pp. 5655–5667, 1997. [15] P. C. Chu, W. Guihua, and Y. Chen, “Japan Sea thermohaline ...structure and circulation . Part III: autocorrelation functions,” Journal of Physical Oceanography, vol. 32, no. 12, pp. 3596–3615, 2002. [16] K.-A. Park and J

  2. Prevalence, risk surfaces and inter-municipality variations in caries experience in Danish children and adolescents in 2012

    DEFF Research Database (Denmark)

    Nørrisgaard, Pia Elisabeth; Qvist, Vibeke; Ekstrand, Kim

    2016-01-01

    Objective The aim of this study was to describe the caries experience, prevalence and distribution related to tooth type and surfaces in the primary and permanent dentition in children and adolescents in Denmark in 2012. In addition, to examine if explanatory factors influence the inter-municipal......-s/DMF. Conclusions The caries distribution within the primary and permanent dentition among 3-, 9-, 15- and 18-year-olds followed definite patterns concerning location on teeth and surfaces. Background factors only explained a minor part of the variation.......Objective The aim of this study was to describe the caries experience, prevalence and distribution related to tooth type and surfaces in the primary and permanent dentition in children and adolescents in Denmark in 2012. In addition, to examine if explanatory factors influence the inter......-municipality variation in caries experience. Materials and methods Data was collected in the public Child Dental Health Service. In total, 5636 caries registrations on 3-, 9-, 15- and 18-year-olds were collected in 35 of the 98 Danish municipalities. Caries experience was expressed by mean def-s/DMF-S and caries...

  3. Spectroscopic study on variations in illite surface properties after acid-base titration.

    Science.gov (United States)

    Liu, Wen-xin; Coveney, R M; Tang, Hong-xiao

    2003-07-01

    FT-IR, Raman microscopy, XRD, 29Si and 27Al MAS NMR, were used to investigate changes in surface properties of a natural illite sample after acid-base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al-Si complexes, preferable to Al(OH)3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si-O and Al-O bonds diminished as a result of treatment with acid, then increased after hydroxide back titration. The varied ratio of signal intensity between (IV)Al and (VI)Al species in 27Al MAS NMR spectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure of illite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illite surfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of the aqueous illite.

  4. Comparison of Surface and Column Variations of CO2 Over Urban Areas for Future Active Remote CO2 Sensors

    Science.gov (United States)

    Choi, Yonghoon; Yang, Melissa; Kooi, Susan; Browell, Edward

    2015-01-01

    High resolution in-situ CO2 measurements were recorded onboard the NASA P-3B during the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) Field Campaign, to investigate the ability of space-based observations to accurately assess near surface conditions related to air quality. This campaign includes, Washington DC/Baltimore, MD (July 2011), San Joaquin Valley, CA (January - February 2013), Houston, TX (September 2013), and Denver, CO (July-August 2014). Each of these campaigns consisted of missed approaches and approximately two hundred vertical soundings of CO2 within the lower troposphere (surface to about 5 km). In this study, surface (0 - 1 km) and column-averaged (0 - 3.5 km) CO2 mixing ratio values from the vertical soundings in the four geographically different urban areas are used to investigate the temporal and spatial variability of CO2 within the different urban atmospheric emission environments. Tracers such as CO, CH2O, NOx, and NMHCs are used to identify the source of CO2 variations in the urban sites. Additionally, we apply nominal CO2 column weighting functions for potential future active remote CO2 sensors operating in the 1.57-microns and 2.05-microns measurement regions to convert the in situ CO2 vertical mixing ratio profiles to variations in CO2 column optical depths, which is what the active remote sensors actually measure. Using statistics calculated from the optical depths at each urban site measured during the DISCOVER-AQ field campaign and for each nominal weighting function, we investigate the natural variability of CO2 columns in the lower troposphere; relate the CO2 column variability to the urban surface emissions; and show the measurement requirements for the future ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) in the continental U.S. urban areas.

  5. Nanoarray-based biomolecular detection using individual Au nanoparticles with minimized localized surface plasmon resonance variations.

    Science.gov (United States)

    Guo, Longhua; Ferhan, Abdul Rahim; Lee, Kijoon; Kim, Dong-Hwan

    2011-04-01

    Here, we present a mean to expand the use of individual metallic nanoparticles to two-dimensional plasmonic nanoarrays. An optical detection platform to track down localized surface plasmon resonance (LSPR) signals of individual nanoparticles on substrates was built for the application of plasmonic nanoarrays. A pseudoimage of nanoparticles on a substrate was reconstructed from their scattering spectra obtained by scanning a user-defined area. The spectral and spatial resolutions of the system were also discussed in detail. Most importantly, we present a method to normalize the localized surface plasmon resonance from geometrically different nanoparticles. After normalization, plasmonic responses from different particles become highly consistent, creating well-fitted dose-response curves of both surrounding refractive index changes and receptor-analyte binding to the surface of individual nanoparticles. Finally, the proof-of-concept system for plasmonic nanoarray detection is demonstrated by the measurement of the aptamer-thrombin binding event.

  6. Surface temperature variations as measured by the Heat Capacity Mapping Mission

    Science.gov (United States)

    Price, J. C.

    1979-01-01

    The AEM-1 satellite, the Heat Capacity Mapping Mission, has acquired high-quality thermal infrared data at times of day especially suited for studying the earth's surface and the exchange of heat and moisture with the atmosphere. Selected imagery illustrates the considerable variability of surface temperature in and around cities, in the dry southwestern United States, in the Appalachian Mountains, and in agricultural areas. Through simplifying assumptions, an analytic experience is derived that relates day/night temperature differences to the near-surface layer (thermal inertia) and to meteorological factors. Analysis of the result suggests that, in arid regions, estimates of relative thermal inertia may be inferred, whereas, in agricultural areas, a hydrologic interpretation is possible.

  7. [Texture variation of CC 5052 aluminum alloy slab from surface to center layer by XRD].

    Science.gov (United States)

    Chen, Ming-Biao; Liu, Wen-Chang; Ma, Xiao-Yi; Li, Jian; Yang, Qing-Xiang; Wang, Shan; Ma, Min; Liu, Chang; Zhao, Y M

    2013-05-01

    For improvement of the processing and gaining uniformity texture structure and performance of direct chill cast CCAA 5052 aluminum alloy band after first hot rolling with different reduction, the material was annealed at 454 degrees C and then cold rolling with different reduction was conducted, the texture at surface, quarter and center layer of the sample was tested and examined by X-ray diffraction method, the data calculated using special software and the difference of texture at surface, quarter and center layer was analyzed. There existed an elevated gradient of intensity from surface layer to center layer after cold rolled with less than or equal to 40% reduction, The main texture of beta is stronger mainly due to transformation from remainder exposure, while the goss and remainder is infirm, the state of texture at each layer is close to each other after cold rolling with reduction high than 56.1%.

  8. Surface modification induced phase transformation and structure variation on the rapidly solidified recast layer of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Ming-Hung [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Haung, Chiung-Fang [School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Division of Family and Operative Dentistry, Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan (China); Shyu, Shih-Shiun [Department of Dentistry, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan (China); Chou, Yen-Ru [Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan (China); Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Lin, Ming-Hong [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Peng, Pei-Wen, E-mail: apon@tmu.edu.tw [School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); and others

    2015-08-15

    In this study, neodymium-doped yttrium orthovanadate (Nd:YVO{sub 4}) as a laser source with different scanning speeds was used on biomedical Ti surface. The microstructural and biological properties of laser-modified samples were investigated by means of optical microscope, electron microscope, X-ray diffraction, surface roughness instrument, contact angle and cell cytotoxicity assay. After laser modification, the rough volcano-like recast layer with micro-/nanoporous structure and wave-like recast layer with nanoporous structure were generated on the surfaces of laser-modified samples, respectively. It was also found out that, an α → (α + rutile-TiO{sub 2}) phase transition occurred on the recast layers of laser-modified samples. The Ti surface becomes hydrophilic at a high speed laser scanning. Moreover, the cell cytotoxicity assay demonstrated that laser-modified samples did not influence the cell adhesion and proliferation behaviors of osteoblast (MG-63) cell. The laser with 50 mm/s scanning speed induced formation of rough volcano-like recast layer accompanied with micro-/nanoporous structure, which can promote cell adhesion and proliferation of MG-63 cell on Ti surface. The results indicated that the laser treatment was a potential technology to enhance the biocompatibility for titanium. - Highlights: • Laser induced the formation of recast layer with micro-/nanoporous structure on Ti. • An α → (α + rutile-TiO{sub 2}) phase transition was observed within the recast layer. • The Ti surface becomes hydrophilic at a high speed laser scanning. • Laser-modified samples exhibit good biocompatibility to osteoblast (MG-63) cell.

  9. Influence of frequency variation in the load behaviour in electric power systems; Influencia da variacao da frequencia no comportamento da carga dos sistemas eletricos de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Sobrinho, Mauro de

    1994-11-01

    This work presents several models for the representation of load-frequency control systems and describes the main characteristics of the load. The composition of the load is described in details, divided by sectors. Finally, simulations of the load-frequency control system is performed. Conclusions are presented.

  10. Immediately loaded machined versus rough surface dental implants in edentulous jaws: One-year postloading results of a pilot randomised controlled trial.

    Science.gov (United States)

    Esposito, Marco; Felice, Pietro; Barausse, Carlo; Pistilli, Roberto; Grandi, Giovanni; Simion, Massimo

    2015-01-01

    To compare the effectiveness of immediately loaded total prostheses supported by implants with a roughened surface versus implants with a machined/turned surface. Fifty edentulous or to-be-rendered edentulous patients requiring an implant-supported cross-arch prosthesis, were randomised either to receive four to eight implants with a roughened surface (25 patients) or with a machined/turned surface (25 patients). Provisional metal-reinforced acrylic prostheses were delivered 48 h after implant placement. Provisional prostheses were replaced after 4 months, by definitive screw-retained metal-resin cross-arch restorations. Outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone level changes. Patients were followed 1 year after loading. One year after loading no patient dropped out. No prosthesis failed, but two machined implants were found to be mobile at definitive impression taking in 1 patient (Fisher's exact test: P = 0.312; difference in proportions = 4%; 95% Cl: -10 to 18). No complications occurred. Both groups presented a significant peri-implant marginal bone loss at 1 year after loading (P < 0.0001), -0.64 ± 0.20 mm for rough implants and -0.68 ± 0.23 mm for turned implants, respectively, with no statistically significant differences between the two groups (P = 0.482; mean difference = 0.04 mm; 95% Cl: -0.17 to 0.25). Up to 1 year after immediate loading, both implant surfaces provided good and similar results, however, the only two implants which failed early in the same patient had a machined surface. These preliminary results must be confirmed by larger trials with longer follow-ups.

  11. Modeling of Axially Loaded Nanowires Embedded in Elastic Substrate Media with Inclusion of Nonlocal and Surface Effects

    Directory of Open Access Journals (Sweden)

    Suchart Limkatanyu

    2013-01-01

    Full Text Available Nonlocal and surface effects are incorporated into a bar-elastic substrate element to account for small-scale and size-dependent effects on axial responses of nanowires embedded in elastic substrate media. The virtual displacement principle, employed to consistently derive the governing differential equation as well as the boundary conditions, forms the core of the displacement-based finite element formulation of the nanowire-elastic substrate element. The element displacement shape functions, analytically derived based on homogeneous solution to the governing differential equilibrium equation of the problem, result in the exact element stiffness matrix and equivalent load vector. Two numerical simulations employing the proposed model are performed to study characteristics and behavior of the nanowire-substrate system. The first simulation involves investigation of responses of the wire embedded in elastic substrate. The second examines influences of several system parameters on the contact stiffness and reveals the size-dependent effect on the effective Young's modulus of the system.

  12. A study of plasma facing tungsten components with electrical discharge machined surface exposed to cyclic thermal loads

    International Nuclear Information System (INIS)

    Seki, Yohji; Ezato, Koichiro; Suzuki, Satoshi; Yokoyama, Kenji; Yamada, Hirokazu; Hirayama, Tomoyuki

    2016-01-01

    Through R&D for a plasma facing units (PFUs) in an outer vertical target of an ITER full-tungsten (W) divertor, Japan Atomic Energy Agency succeeded in demonstrating the durability of the W divertor shaped by an electrical discharge machining (EDM). To prevent melting of W armors in the PFUs, an adequate technology to meet requirements of a geometrical shape and a tolerance is one of the most important key issues in a manufacturing process. From the necessity, the EDM has been evaluated to control the final shape of the W armor. Though the EDM was known to be advantages such as an easy workability, a potential disadvantage of presence of micro-cracks on the W surface appeared. In order to examine a potential effect of the micro-crack on a heat removal durability, a high heat flux testing was carried out for the W divertor mock-up with the polish and the EDM. As the result, all of the W armors endured the repetitive heat load of 1000 cycles at an absorbed heat flux of more than 20 MW/m 2 , which strongly encourages the realization of the PFUs of the ITER full-W divertor with the various geometrical shape and the high accuracy tolerance.

  13. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    Directory of Open Access Journals (Sweden)

    Shrivastava Sachin

    2015-01-01

    Full Text Available The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI in unidirectional fibrous laminates using Genetic-Algorithms (GA under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT. The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  14. Design and analysis of drum lathe for manufacturing large-scale optical microstructured surface and load characteristics of aerostatic spindle

    Science.gov (United States)

    Wu, Dongxu; Qiao, Zheng; Wang, Bo; Wang, Huiming; Li, Guo

    2014-08-01

    In this paper, a four-axis ultra-precision lathe for machining large-scale drum mould with microstructured surface is presented. Firstly, because of the large dimension and weight of drum workpiece, as well as high requirement of machining accuracy, the design guidelines and component parts of this drum lathe is introduced in detail, including control system, moving and driving components, position feedback system and so on. Additionally, the weight of drum workpiece would result in the structural deformation of this lathe, therefore, this paper analyses the effect of structural deformation on machining accuracy by means of ANSYS. The position change is approximately 16.9nm in the X-direction(sensitive direction) which could be negligible. Finally, in order to study the impact of bearing parameters on the load characteristics of aerostatic journal bearing, one of the famous computational fluid dynamics(CFD) software, FLUENT, is adopted, and a series of simulations are carried out. The result shows that the aerostatic spindle has superior performance of carrying capacity and stiffness, it is possible for this lathe to bear the weight of drum workpiece up to 1000kg since there are two aerostatic spindles in the headstock and tailstock.

  15. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    Science.gov (United States)

    Shrivastava, Sachin; Mohite, P. M.

    2015-01-01

    The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC) skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI) in unidirectional fibrous laminates using Genetic-Algorithms (GA) under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT). The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  16. Model test setup and program for experimental estimation of surface loads of the SSG Kvitsoey pilot plant from extreme wave conditions[Seawave Slot-cone Generators

    Energy Technology Data Exchange (ETDEWEB)

    Juul Larsen, B.; Kofoed, J.P.

    2005-10-15

    The purpose of the tests is to find the wave induced surface loads on the SSG pilot plant when exposed to extreme wave conditions, ie. the design loads. The design sea states used in the model tests are found through a study of the wave climate from a number of different sources, as described in chapter 2. Based on the hereby obtained extreme wave data for the SSG pilot plant location a test program has been designed to establish the surface loads on the SSG pilot plant in various relevant sea states, see chapter 3. A description of the test setup and the model is made in detail including a description of the instrumentation and data acquisition and also the data analysis. (au)

  17. Spatio-temporal variations in surface characteristics over the North American Monsoon region

    Science.gov (United States)

    In this paper we summarize the surface characteristics for six locations in western Mexico and southwestern USA (from a subhumid climate in Jalisco, Mexico to the Sonoran Desert climate in Arizona, USA),that lie along a meridional transect within the North American Monsoon (NAM) core region using av...

  18. Near-surface remote sensing of spatial and temporal variation in canopy phenology

    Science.gov (United States)

    Andrew D. Richardson; Bobby H. Braswell; David Y. Hollinger; Julian P. Jenkins; Scott V. Ollinger

    2009-01-01

    There is a need to document how plant phenology is responding to global change factors, particularly warming trends. "Near-surface" remote sensing, using radiometric instruments or imaging sensors, has great potential to improve phenological monitoring because automated observations can be made at high temporal frequency. Here we build on previous work and...

  19. Seasonal variation in surface fuel moisture between unthinned and thinned mixed conifer forest, northern California, USA

    Science.gov (United States)

    Becky L. Estes; Eric E. Knapp; Carl N. Skinner; Fabian C. C. Uzoh

    2012-01-01

    Reducing stand density is often used as a tool for mitigating the risk of high-intensity crown fires. However, concern has been expressed that opening stands might lead to greater drying of surface fuels, contributing to increased fire risk. The objective of this study was to determine whether woody fuel moisture differed between unthinned and thinned mixed-conifer...

  20. Variational derivation of KdV-type of models for surface water waves

    NARCIS (Netherlands)

    van Groesen, Embrecht W.C.; Andonowati, A.

    2007-01-01

    Using the Hamiltonian formulation of surface waves, we approximate the kinetic energy and restrict the governing generalized action principle to a submanifold of uni-directional waves. Different from the usual method of using a series expansion in parameters related to wave height and wavelength,

  1. Variation with age of anisotropy under oceans, from great circle surface waves

    International Nuclear Information System (INIS)

    Journet, B.; Jobert, N.

    1982-01-01

    Global great circle measurements of regionalized mantle Love wave phase velocities are interpreted in terms of regional models. The same study had been made by J. J. Leveque (1980) for Rayleigh waves, and the resulting models for the two oceanic regions of different ages are used as a basis for comparison: the observed Love wave dispersion cannot be explained with these models if isotropic. The models obtained by inversion of Love wave data are compared with the models mentioned; the discrepancy appearing in the 250 km depth range between the velocities β/sub H/ and β/sub V/ of respectively SH and SV waves is indicative of polarization anisotropy. Moreover, we put forward a significant variation from young to old oceans: the difference between β/sub H/, and β/sub V/ is of the order of 1% for the former, compared to 3% for the latter. This variation can bring information about the behaviour of upper mantle materials in connection with the motion of oceanic plates

  2. A 5-year prospective multicenter study on 1-stage smooth-surface Branemark System implants with early loading in edentulous mandibles

    NARCIS (Netherlands)

    Friberg, Bertil; Raghoebar, Gerry M.; Grunert, Ingrid; Hobkirk, John A.; Tepper, Gabor

    2008-01-01

    Purpose: The purpose of the current prospective multicenter Study was to evaluate the 5-year implant success and peri-implant conditions of smooth-surface Branemark System implants when using a novel technique including a 1-stage surgical procedure with early loading in edentulous mandibles.

  3. Exploring the biomechanical load of a sliding on the skin: understanding the acute skin injury mechanism of player-surface interaction

    NARCIS (Netherlands)

    Eijnde, W.A.J. van den; Meijer, K.; Lamers, E.; Peppelman, M.; Erp, P.E. van

    2017-01-01

    BACKGROUND: Currently, there is a shortage of biomechanical data regarding acute skin injury mechanisms that are involved in player-surface contact in soccer on artificial turf. It is hypothesized that peak loads on the skin during the landing phase are an important factor in causing an acute skin

  4. Sensitivity of thermal inertia calculations to variations in environmental factors. [in mapping of Earth's surface by remote sensing

    Science.gov (United States)

    Kahle, A. B.; Alley, R. E.; Schieldge, J. P.

    1984-01-01

    The sensitivity of thermal inertia (TI) calculations to errors in the measurement or parameterization of a number of environmental factors is considered here. The factors include effects of radiative transfer in the atmosphere, surface albedo and emissivity, variations in surface turbulent heat flux density, cloud cover, vegetative cover, and topography. The error analysis is based upon data from the Heat Capacity Mapping Mission (HCMM) satellite for July 1978 at three separate test sites in the deserts of the western United States. Results show that typical errors in atmospheric radiative transfer, cloud cover, and vegetative cover can individually cause root-mean-square (RMS) errors of about 10 percent (with atmospheric effects sometimes as large as 30-40 percent) in HCMM-derived thermal inertia images of 20,000-200,000 pixels.

  5. Variations in Near-Infrared Emissivity of Venus Surface Observed by the Galileo Near-Infrared Mapping Spectrometer

    Science.gov (United States)

    Hashimoto, G. L.; Roos-Serote, M.; Sugita, S.

    2004-11-01

    We evaluate the spatial variation of venusian surface emissivity at a near-infrared wavelength using multispectral images obtained by the Near-Infrared Mapping Spectrometer (NIMS) on board the Galileo spacecraft. The Galileo made a close flyby to Venus in February 1990. During this flyby, NIMS observed the nightside of Venus with 17 spectral channels, which includes the well-known spectral windows at 1.18, 1.74, and 2.3 μ m. The surface emissivity is evaluated at 1.18 μ m, at which thermal radiation emitted from the planetary surface could be detected. To analyze the NIMS observations, synthetic spectra have been generated by means of a line-by-line radiative transfer program which includes both scattering and absorption. We used the discrete ordinate method to calculate the spectra of vertically inhomogeneous plane-parallel atmosphere. Gas opacity is calculated based on the method of Pollack et al. (1993), though binary absorption coefficients for continuum opacity are adjusted to achieve an acceptable fit to the NIMS data. We used Mie scattering theory and a cloud model developed by Pollack et al. (1993) to determine the single scattering albedo and scattering phase function of the cloud particles. The vertical temperature profile of Venus International Reference Atmosphere (VIRA) is used in all our calculations. The procedure of the analysis is the followings. We first made a correction for emission angle. Then, a modulation of emission by the cloud opacities is removed using simultaneously measured 1.74 and 2.3 μ m radiances. The resulting images are correlated with the topographic map of Magellan. To search for variations in surface emissivity, this cloud corrected images are divided by synthetic radiance maps that were created from the Magellan data. This work has been supported by The 21st Century COE Program of Origin and Evolution of Planetary Systems of Ministry of Education, Culture, Sports, Science and Technology (MEXT).

  6. Mineralogical Variation of Chelyabinsk with Depth from the Surface of the Parent Meteoroid

    Science.gov (United States)

    Yoshida, S.; Mikouchi, T.; Nagao, K.; Haba, M. K.; Hasegawa, H.; Komatsu, M.; Zolensky, M. E.

    2014-01-01

    The Chelyabinsk meteorite, which passed over the Chelyabinsk Oblast, Russia on Feb. 15th, 2013, brought serious damage by the shock wave and airburst. The diameter of the parent meteoroid is estimated to be approximately 20 m in diameter [1]. It was reported that the impact by this meteorite shower was 4,000 times as large as the TNT explosive and this was the largest airburst on Earth since the asteroid impact in Tunguska, Russia in 1908. The mineralogy and geochemical study of the recovered samples shows that Chelyabinsk is an LL5 chondrite [1]. In this study we analyzed several fragments of Chelyabinsk whose noble gas compositions have been measured and depths from the surface of the parent meteoroid were estimated [2]. We examined how mineralogical characteristics change with depth from the surface. This kind of study has never been performed and thus may be able to offer significant information about the evolution of meteorite parent bodies.

  7. Long-term variations in the surface air 7Be concentration and climatic changes.

    Science.gov (United States)

    Jiwen, Liu; Starovoitova, Valeriia N; Wells, Douglas P

    2013-02-01

    We have used EML Surface Air Sampling Program (SASP) data to analyze the long-term trend in (7)Be surface concentration and address possible correlation between this long-term trend and climatic changes, namely changes in precipitation patterns and temperature. In this paper we present (7)Be concentration data from 23 sites, spanning over 25 years, all over the world, and extract long-term trend parameter using two independent techniques. The (7)Be concentrations in most stations show a pronounced decreasing trend, potentially corresponding to statistically significant changes in transporting (7)Be from upper atmosphere source to these sites. Weak negative correlation between (7)Be concentration and amount of precipitation was also observed. However, more data from more representative sites around the world are needed the statistical robustness of this trend. Published by Elsevier Ltd.

  8. Variations in surface roughness of seven orthodontic archwires: an SEM-profilometry study

    OpenAIRE

    Amini, Fariborz; Rakhshan, Vahid; Pousti, Maryam; Rahimi, Hajir; Shariati, Mahsa; Aghamohamadi, Bahareh

    2012-01-01

    Objective The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. Methods This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodonti...

  9. Candida albicans CUG Mistranslation Is a Mechanism To Create Cell Surface Variation

    OpenAIRE

    Miranda, Isabel; Silva-Dias, Ana; Rocha, Rita; Teixeira-Santos, Rita; Coelho, Carolina; Gon?alves, Teresa; Santos, Manuel A. S.; Pina-Vaz, Cid?lia; Solis, Norma V.; Filler, Scott G.; Rodrigues, Ac?cio G.

    2013-01-01

    ABSTRACT In the human fungal pathogen Candida albicans, the CUG codon is translated 97% of the time as serine and 3% of the time as leucine, which potentially originates an array of proteins resulting from the translation of a single gene. Genes encoding cell surface proteins are enriched in CUG codons; thus, CUG mistranslation may influence the interactions of the organism with the host. To investigate this, we compared a C.?albicans strain that misincorporates 28% of leucine at CUGs with a ...

  10. Atmospheric summer teleconnections and Greenland Ice Sheet surface mass variations: insights from MERRA-2

    International Nuclear Information System (INIS)

    Lim, Young-Kwon; Schubert, Siegfried D; Molod, Andrea M; Cullather, Richard I; Zhao, Bin; Nowicki, Sophie M J; Lee, Jae N; Velicogna, Isabella

    2016-01-01

    The relationship between leading atmospheric teleconnection patterns and Greenland Ice Sheet (GrIS) temperature, precipitation, and surface mass balance (SMB) are investigated for the last 36 summers (1979–2014) based on Modern-Era Retrospective analysis for Research and Applications version 2 reanalyses. The results indicate that the negative phase of both the North Atlantic Oscillation (NAO) and Arctic Oscillation, associated with warm and dry conditions for the GrIS, lead to SMB decreases within 0–1 months. Furthermore, the positive phase of the East Atlantic (EA) pattern often lags the negative NAO, reflecting a dynamical linkage between these modes that acts to further enhance the warm and dry conditions over the GrIS, leading to a favorable environment for enhanced surface mass loss. The development of a strong negative NAO in combination with a strong positive EA in recent years leads to significantly larger GrIS warming compared to when the negative NAO occurs in combination with a negative or weak positive EA (0.69 K versus 0.13 K anomaly). During 2009 and 2011, weakened (as compared to conditions during the severe surface melt cases of 2010 and 2012) local high pressure blocking produced colder northerly flow over the GrIS inhibiting warming despite the occurrence of a strong negative NAO, reflecting an important role for the EA during those years. In particular, the EA acts with the NAO to enhance warming in 2010 and 2012, and weaken high pressure blocking in 2009 and 2011. In general, high pressure blocking primarily impacts the western areas of the GrIS via advective temperature increases, while changes in net surface radiative fluxes account for both western and eastern GrIS temperature changes. (letter)

  11. Albedo, Land Cover, and Daytime Surface Temperature Variation Across an Urbanized Landscape

    Science.gov (United States)

    Trlica, A.; Hutyra, L. R.; Schaaf, C. L.; Erb, A.; Wang, J. A.

    2017-11-01

    Land surface albedo is a key parameter controlling the local energy budget, and altering the albedo of built surfaces has been proposed as a tool to mitigate high near-surface temperatures in the urban heat island. However, most research on albedo in urban landscapes has used coarse-resolution data, and few studies have attempted to relate albedo to other urban land cover characteristics. This study provides an empirical description of urban summertime albedo using 30 m remote sensing measurements in the metropolitan area around Boston, Massachusetts, relating albedo to metrics of impervious cover fraction, tree canopy coverage, population density, and land surface temperature (LST). At 30 m spatial resolution, median albedo over the study area (excluding open water) was 0.152 (0.112-0.187). Trends of lower albedo with increasing urbanization metrics and temperature emerged only after aggregating data to 500 m or the boundaries of individual towns, at which scale a -0.01 change in albedo was associated with a 29 (25-35)% decrease in canopy cover, a 27 (24-30)% increase in impervious cover, and an increase in population from 11 to 386 km-2. The most intensively urbanized towns in the region showed albedo up to 0.035 lower than the least urbanized towns, and mean mid-morning LST 12.6°C higher. Trends in albedo derived from 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) measurements were comparable, but indicated a strong contribution of open water at this coarser resolution. These results reveal linkages between albedo and urban land cover character, and offer empirical context for climate resilient planning and future landscape functional changes with urbanization.

  12. Spatial Variation of Surface Energy Fluxes Due to Land Use Changes across China

    Directory of Open Access Journals (Sweden)

    Enjun Ma

    2014-04-01

    Full Text Available We estimate the heat flux changes caused by the projected land transformation over the next 40 years across China to improve the understanding of the impacts of land dynamics on regional climate. We use the Weather Research and Forecasting (WRF model to investigate these impacts in four representative land transformation zones, where reclamation, overgrazing, afforestation, and urbanization dominates the land use and land cover changes in each zone respectively. As indicated by the significant variance of albedo due to different land use and cover changes, different surface properties cause great spatial variance of the surface flux. From the simulation results, latent heat flux increases by 2 and 21 W/m2 in the reclamation and afforestation regions respectively. On the contrary, overgrazing and urban expansion results in decrease of latent heat flux by 5 and 36 W/m2 correspondingly. Urban expansion leads to an average increase of 40 W/m2 of sensible heat flux in the future 40 years, while reclamation, afforestation, as well as overgrazing result in the decrease of sensible heat flux. Results also show that reclamation and overgrazing lead to net radiation decrease by approximately 4 and 7 W/m2 respectively, however, afforestation and urbanization lead to net radiation increase by 6 and 3 W/m2 respectively. The simulated impacts of projected HLCCs on surface energy fluxes will inform sustainable land management and climate change mitigation.

  13. Evolution of Mars’ Northern Polar Seasonal CO2 deposits: variations in surface brightness and bulk density

    Science.gov (United States)

    Mount, Christopher P.; Titus, Timothy N.

    2015-01-01

    Small scale variations of seasonal ice are explored at different geomorphic units on the Northern Polar Seasonal Cap (NPSC). We use seasonal rock shadow measurements, combined with visible and thermal observations, to calculate density over time. The coupling of volume density and albedo allows us to determine the microphysical state of the seasonal CO2 ice. We find two distinct endmembers across the NPSC: 1) Snow deposits may anneal to form an overlying slab layer that fractures. These low density deposits maintain relatively constant densities over springtime. 2) Porous slab deposits likely anneal rapidly in early spring and fracture in late spring. These high density deposits dramatically increase in density over time. The endmembers appear to be correlated with latitude.

  14. Response of rapidly developing extratropical cyclones to sea surface temperature variations over the western Kuroshio-Oyashio confluence region

    Science.gov (United States)

    Hirata, Hidetaka; Kawamura, Ryuichi; Kato, Masaya; Shinoda, Taro

    2016-04-01

    The dynamical response of rapidly developing extratropical cyclones to sea surface temperature (SST) variations over the western Kuroshio-Oyashio confluence (WKOC) region was examined by using regional cloud-resolving simulations. This study specifically highlights an explosive cyclone that occurred in early February 2014 and includes a real SST experiment (CNTL run) and two sensitivity experiments with warm and cool SST anomalies over the WKOC region (warm and cool runs). The results derived from the CNTL run indicated that moisture supply from the ocean was enhanced when the dry air associated with the cold conveyor belt (CCB) overlapped with warm currents. Further, the evaporated moisture contributed substantially to latent heat release over the bent-back front with the aid of the CCB, leading to cyclone intensification and strengthening of the asymmetric structure around the cyclone's center. Such successive processes were more active in the warm run than in the cool run. The dominance of the zonally asymmetric structure resulted in a difference in sea level pressure around the bent-back front between the two runs. The WKOC SST variations have the potential to affect strong wind distributions along the CCB through modification of the cyclone's inner system. Additional experiments with two other cyclones showed that the cyclone response to the WKOC SST variations became evident when the CCB north of the cyclone's center overlapped with that region, confirming that the dry nature of the CCB plays an important role in latent heat release by allowing for larger moisture supply from the ocean.

  15. Characterizing bacterial communities in tilapia pond surface sediment and their responses to pond differences and temporal variations.

    Science.gov (United States)

    Fan, Limin; Barry, Kamira; Hu, Gengdong; Meng, Shunlong; Song, Chao; Qiu, Liping; Zheng, Yao; Wu, Wei; Qu, Jianhong; Chen, Jiazhang; Xu, Pao

    2017-01-01

    Bacterial community compositions in the surface sediment of tilapia ponds and their responses to pond characteristics or seasonal variations were investigated. For that, three ponds with different stocking densities were selected to collect the samples. And the method of Illumina high-throughput sequencing was used to amplify the bacterial 16S rRNA genes. A total of 662, 876 valid reads and 5649 operational taxonomic units were obtained. Further analysis showed that the dominant phyla in all three ponds were Proteobacteria, Bacteroidetes, Chloroflexi, and Acidobacteria. The phyla Planctomycetes, Firmicutes, Chlorobi, and Spirochaetae were also relatively abundant. Among the eight phyla, the abundances of only Proteobacteria, Bacteroidetes, Firmicutes, and Spirochaetae were affected by seasonal variations, while seven of these (with the exception of Acidobacteria) were affected by pond differences. A comprehensive analysis of the richness and diversity of the bacterial 16S rRNA gene, and of the similarity in bacterial community composition in sediment also showed that the communities in tilapia pond sediment were shaped more by pond differences than by seasonal variations. Linear discriminant analysis further indicated that the influences of pond characteristics on sediment bacterial communities might be related to feed coefficients and stocking densities of genetically improved farmed tilapia (GIFT).

  16. Inter-Seasonal Variations of Surface Temperature in the Urbanized Environment of Delhi Using Landsat Thermal Data

    Directory of Open Access Journals (Sweden)

    Ram Babu Singh

    2014-03-01

    Full Text Available Complex land use/cover patterns in urban areas significantly influence their prevailing surface temperature conditions. As a result of differential cooling and heating of various land use/cover, large temperature ranges are associated with bare land, built-up land, etc. and low ranges are found in vegetation cover and water bodies. Extremely high and low temperature conditions in built-up land have direct and negative impacts on health conditions, and therefore are imperative to study. Thus, an attempt has been made in this research to analyze seasonal variations in surface temperature in city of Delhi. Landsat Thematic Mapper (TM 5 satellite images for the four seasons, viz., 16 January (winter, 5 March (spring, 8 May (summer and 29 September (autumn 2011 have been used to interpret the distribution and changes in surface temperature. A total of 80 samples from all land use/cover categories were taken to generalize the patterns along with north-south and west-east profiles. The extracted surface temperature patterns reflect the spatial and temporal dynamics of temperature over different land use/cover. The north-south and west-east gradient of temperature demonstrates that the core of Delhi has a much lower temperature and weak urban heat island (UHI phenomenon.

  17. Temporal variations of surface water quality in urban, suburban and rural areas during rapid urbanization in Shanghai, China

    International Nuclear Information System (INIS)

    Wang Junying; Da Liangjun; Song Kun; Li Bailian

    2008-01-01

    As the economic and financial center of China, Shanghai has experienced an extensive urban expansion since the early 1980s, with an attendant cost in environmental degradation. We use an integrated pollution index to study the temporal variations of surface water quality in urban, suburban and rural areas between 1982 and 2005. Data on monitored cross-sections were collected from the Shanghai Environmental Monitoring Center. The results indicated that the spatial pattern of surface water quality was determined by the level of urbanization. Surface water qualities in urban and suburban areas were improved by strengthening the environmental policies and management, but were worsening in rural areas. The relationship between economic growth and surface water quality in Shanghai showed an inversed-U-shaped curve, which reflected a similar pattern in most developed countries. This research suggests that decision makers and city officials should be more aware of the recent pollution increases in Shanghai. - An integrated pollution index documents the deterioration of water quality in greater Shanghai, recently most serious in rural sections

  18. Role of Surface Wind and Vegetation Cover in Multi-decadal Variations of Dust Emission in the Sahara and Sahel

    Science.gov (United States)

    Kim, Dong; Chin, Mian; Remer, Lorraine A.; Diehl, Thomas L.; Bian, Huisheng; Yu, Hongbin; Brown, Molly E.; Stockwell, William R.

    2016-01-01

    North Africa, the world's largest dust source, is non-uniform, consisting of a permanently arid region (Sahara), a semi-arid region (Sahel), and a relatively moist vegetated region (Savanna), each with very different rainfall patterns and surface conditions. This study aims to better understand the controlling factors that determine the variation of dust emission in North Africa over a 27-year period from 1982 to 2008, using observational data and model simulations. The results show that the model-derived Saharan dust emission is only correlated with the 10-m winds (W10m) obtained from reanalysis data, but the model-derived Sahel dust emission is correlated with both W10m and the Normalized Difference Vegetation Index (NDVI) that is obtained from satellite. While the Saharan dust accounts for 82 of the continental North Africa dust emission (1340-1570 Tg year(exp -1) in the 27-year average, the Sahel accounts for 17 with a larger seasonal and inter-annual variation (230-380 Tg year(exp -1), contributing about a quarter of the transatlantic dust transported to the northern part of South America. The decreasing dust emission trend over the 27-year period is highly correlated with W10m over the Sahara (R equals 0.92). Over the Sahel, the dust emission is correlated with W10m (R 0.69) but is also anti-correlated with the trend of NDVI (R equals 0.65). W10m is decreasing over both the Sahara and the Sahel between 1982 and 2008, and the trends are correlated (R equals 0.53), suggesting that Saharan Sahelian surface winds are a coupled system, driving the inter-annual variation of dust emission.

  19. Magnetic loading of TiO2/SiO2/Fe3O4 nanoparticles on electrode surface for photoelectrocatalytic degradation of diclofenac

    International Nuclear Information System (INIS)

    Hu, Xinyue; Yang, Juan; Zhang, Jingdong

    2011-01-01

    Highlights: ► Magnetic TSF nanoparticles are immobilized on electrode surface with aid of magnet. ► Magnetically attached TSF electrode shows high photoelectrochemical activity. ► Diclofenac is effectively degraded on TSF-loaded electrode by photoelectrocatalysis. ► Photoelectrocatalytic degradation of diclofenac is monitored with voltammetry. - Abstract: A novel magnetic nanomaterials-loaded electrode developed for photoelectrocatalytic (PEC) treatment of pollutants was described. Prior to electrode fabrication, magnetic TiO 2 /SiO 2 /Fe 3 O 4 (TSF) nanoparticles were synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR measurements. The nanoparticles were dispersed in ethanol and then immobilized on a graphite electrode surface with aid of magnet to obtain a TSF-loaded electrode with high photoelectrochemical activity. The performance of the TSF-loaded electrode was tested by comparing the PEC degradation of methylene blue in the presence and absence of magnet. The magnetically attached TSF electrode showed higher PEC degradation efficiency with desirable stability. Such a TSF-loaded electrode was applied to PEC degradation of diclofenac. After 45 min PEC treatment, 95.3% of diclofenac was degraded on the magnetically attached TSF electrode.

  20. Surface potential variations on a silicon nanowire transistor in biomolecular modification and detection

    International Nuclear Information System (INIS)

    Tsai, Chia-Chang; Chiang, Pei-Ling; Lin, Tsung-Wu; Chen, Yit-Tsong; Sun, Chih-Jung; Tsai, Ming-Hsueh; Chang, Yun-Chorng

    2011-01-01

    Using a silicon nanowire field-effect transistor (SiNW-FET) for biomolecule detections, we selected 3-(mercaptopropyl)trimethoxysilane (MPTMS), N-[6-(biotinamido)hexyl]-3 ' -(2 ' -pyridyldithio) propionamide (biotin-HPDP), and avidin, respectively, as the designated linker, receptor, and target molecules as a study model, where the biotin molecules were modified on the SiNW-FET to act as a receptor for avidin. We applied high-resolution scanning Kelvin probe force microscopy (KPFM) to detect the modified/bound biomolecules by measuring the induced change of the surface potential (ΔΦ s ) on the SiNW-FET under ambient conditions. After biotin-immobilization and avidin-binding, the ΔΦ s on the SiNW-FET characterized by KPFM was demonstrated to correlate to the conductance change inside the SiNW-FET acquired in aqueous solution. The ΔΦ s values on the SiNW-FET caused by the same biotin-immobilization and avidin-binding were also measured from drain current versus gate voltage curves (I d -V g ) in both aqueous condition and dried state. For comparison, we also study the ΔΦ s values on a Si wafer caused by the same biotin-immobilization and avidin-binding through KPFM and ζ potential measurements. This study has demonstrated that the surface potential measurement on a SiNW-FET by KPFM can be applied as a diagnostic tool that complements the electrical detection with a SiNW-FET sensor. Although the KPFM experiments were carried out under ambient conditions, the measured surface properties of a SiNW-FET are qualitatively valid compared with those obtained by other biosensory techniques performed in liquid environment.

  1. Four-season variation of 2014 year in the surface sediments of the Gochang beach, southwestern coast of Korea

    Science.gov (United States)

    Ryang, Woo Hun; Kang, Sol-Ip

    2015-04-01

    The marco-tide, open-coast Gochang beach, located on the southwestern coast of Korea, was studied in terms of four season variations in surface sediment and sedimentary environment. During the four seasons of winter (February), spring (May), summer (August), and fall (November) in 2014 year, surface sediments of total 252 sites were sampled across three survey lines, consisting of 21 sites at 30 m intervals in each transverse line to the coast, respectively. The Gochang beach comprises the Dongho, Kwangseungri, and Myeongsasipri beaches from north to south. The pocket-type Dongho beach is mainly composed of very fine sands to very coarse sands, and the ratio of fine sand is the largest. The average of grain size is the coarsest in the winter. The spatial distribution of surface sediments shows a coast-parallel trend of fine and medium sands during the four seasons. During the winter, the upper tidal flat was dominated by medium sand, while the lower tidal flat was dominated by find sand. The surface sediments of the Kwangseungri beach are mainly composed of fine-grained sands, and the mean grain size is the coarsest in winter. Grain-size distribution shows a uni-mode pattern in the four seasons. Mud facies partly exist in spring and summer seasons, whereas it is rarely shown in autumn and winter. The spatial distribution of surface sediments shows a coast-parallel trend of fine to coarse sand during the four seasons. The Myeongsasipri beach is mainly composed of very fine sands to very coarse sands, and the ratio of fine sand is the largest. Grain-size distribution shows a weak bi-modal trend in the autumn and a uni-mode pattern in the spring, summer and winter. The mean grain size of the winter is the coarsest among those of four seasons. The spatial distribution of four seasons also shows a coast-parallel trend. During the four seasons of 2014 year in the Gochang beach, overall distribution of the grain sizes represents a fining trend from upper to lower tidal

  2. Characterizing the magnetic memory signals on the surface of plasma transferred arc cladding coating under fatigue loads

    Science.gov (United States)

    Huang, Haihong; Han, Gang; Qian, Zhengchun; Liu, Zhifeng

    2017-12-01

    The metal magnetic memory signals were measured during dynamic tension tests on the surfaces of the cladding coatings by plasma transferred arc (PTA) welding and the 0.45% C steel. Results showed that the slope of the normal component Hp(y) of magnetic signal and the average value of the tangential component Hp(x) reflect the magnetization of the specimens. The signals increased sharply in the few initial cycles; and then fluctuated around a constant value during fatigue process until fracture. For the PTA cladding coating, the slope of Hp(y) was steeper and the average of Hp(x) was smaller, compared with the 0.45% C steel. The hysteresis curves of cladding layer, bonding layer and substrate were measured by vibrating sample magnetometer testing, and then saturation magnetization, initial susceptibility and coercivity were further calculated. The stress-magnetization curves were also plotted based on the J-A model, which showed that the PTA cladding coating has smaller remanence and coercivity compared with the 0.45% C steel. The microstructures of cladding coating confirmed that the dendritic structure and second-phase of alloy hinder the magnetic domain motion, which was the main factor influencing the variation of magnetic signal during the fatigue tests.

  3. THE HUBBLE WIDE FIELD CAMERA 3 TEST OF SURFACES IN THE OUTER SOLAR SYSTEM: SPECTRAL VARIATION ON KUIPER BELT OBJECTS

    International Nuclear Information System (INIS)

    Fraser, Wesley C.; Brown, Michael E.; Glass, Florian

    2015-01-01

    Here, we present additional photometry of targets observed as part of the Hubble Wide Field Camera 3 (WFC3) Test of Surfaces in the Outer Solar System. Twelve targets were re-observed with the WFC3 in the optical and NIR wavebands designed to complement those used during the first visit. Additionally, all of the observations originally presented by Fraser and Brown were reanalyzed through the same updated photometry pipeline. A re-analysis of the optical and NIR color distribution reveals a bifurcated optical color distribution and only two identifiable spectral classes, each of which occupies a broad range of colors and has correlated optical and NIR colors, in agreement with our previous findings. We report the detection of significant spectral variations on five targets which cannot be attributed to photometry errors, cosmic rays, point-spread function or sensitivity variations, or other image artifacts capable of explaining the magnitude of the variation. The spectrally variable objects are found to have a broad range of dynamical classes and absolute magnitudes, exhibit a broad range of apparent magnitude variations, and are found in both compositional classes. The spectrally variable objects with sufficiently accurate colors for spectral classification maintain their membership, belonging to the same class at both epochs. 2005 TV189 exhibits a sufficiently broad difference in color at the two epochs that span the full range of colors of the neutral class. This strongly argues that the neutral class is one single class with a broad range of colors, rather than the combination of multiple overlapping classes

  4. Fatty Alcohol Variations in Surface Sediments of Sungai Sepang Besar, Sepang, Selangor

    International Nuclear Information System (INIS)

    Masni Mohd Ali; Norfariza Humrawali; Ying, P.Q.; Mohd Talib Latif; Mohamad Pauzi Zakaria

    2011-01-01

    Composition of fatty alcohols from 19 surface sediment samples collected along Sungai Sepang Besar, Sepang, Selangor were determined. The sediments were extracted and analysed using the Gas Chromatography-Mass Spectrometry (GC-MS) technique. A total of 19 fatty alcohols from C 12 to C 30 including 4 branched compounds were identified with concentrations in the range 0.02 μg/ g - 9.01 μg/ g dry weight. C 26 fatty alcohols dominated most sampling stations with concentrations ranging from 0.29 to 5.43 μg/ g dry weight and constituted 15.5 % of total fatty alcohols. According to individual compounds of fatty alcohols and the [Σ(C 12 - C 20 )/ Σ(C 22 - C 30 )] ratio, Sungai Sepang Besar has a high composition of short-chain fatty alcohols (C 12 - C 20 ) which mainly originate from marine organisms. However, the Alcohol Sources Index (ASI) showed that terrestrial derived fatty alcohols dominated the area due to high concentration of C 26 compounds in most sampling stations. The value of (odd chain length)/ (even chain length) ratios were high for almost all the sampling stations due to high bacterial activities. It can be concluded that the surface sediments of Sungai Sepang Besar contained organic materials from marine, terrestrial and bacterial sources. (author)

  5. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners

    Directory of Open Access Journals (Sweden)

    W. An

    2015-01-01

    Full Text Available Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; −10° with and without their usual running shoes. Vertical average rate (VALR and instantaneous loading rate (VILR were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p0.382. There was no difference (p>0.413 in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p>0.15. Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p<0.011.

  6. Sediment budget and interannual variations of suspended sediment load in the Rio Cordon (Italy). Three decades of monitoring and investigations (1987-2014).

    Science.gov (United States)

    García-Rama, Adriana; Rainato, Riccardo; Mao, Luca; Picco, Lorenzo; Aristide Lenzi, Mario

    2015-04-01

    This work shows the results of 28 years of measurements carried out in the Rio Cordon catchment, an Alpine watershed where a measuring station continuously recorded water discharge, bedload and suspended sediment transport since 1987. Hourly values of discharge and suspended sediment transport (or 5 min interval during flood events) have been studied throughout the whole study period. Annual and seasonal variations of suspended sediment load during the study period were analyzed along with their contribution to the total sediment yield. Comparing these almost three decades, the highest suspended solid transport occurred in 1994, 2001, 1987, 1998, 2002 and 2009, during which it was 2521.5, 1568.5, 792, 745, 551 and 514.8 t year-1, respectively. Summer and autumn contributions were significant in 1989, 1994, 1996, 1998, 2002, and 2005; on the other hand 2001 was characterized by a snowmelt flood that generated almost all the suspended load. A notable variability of the suspended solid transport can be observed taking in count snowmelt floods. Also 1987, 2001, 2008, 2009 and 2010 are characterized by a very important role of this kind of runoff. Data collected in the Rio Cordon for 28 years show that 75.2% of the total sediment load (10597.8 t of 14088.8 t) was due to suspended sediment transport. In 1994 and 2001, a large portion of the suspended sediment load was mainly supplied during the flood events that occurred in September 1994 and May 2001, which produced 198 and 1017.5 t respectively. Averaging 28 years of data, the mean annual specific sediment yield turns out to be around 102,9 t km-2 year-1. However, this value includes the 1986-1993 period characterized by ordinary flood events during which de mean sediment production was 65.34 t km-2 year-1, the massive sediment yield in 1994 (803.4 t km-2 year-1), the 1995-2000 period (93.2 t km-2 year-1), the 2001 (343.8 km-2 year-1) and the 2002-2014 period(54.5 t km-2 year-1). The highest values correspond to 1994

  7. Dynamics of Nitrogen loads in surface water of an agricultural watershed by modelling approach, the Save, Southwest France.

    Science.gov (United States)

    Ferrant, S.; Oeurng, C.; Sauvage, S.; Durand, P.; Probst, J. L.; Sanchez-Perez, J. M.

    2009-04-01

    Agriculture is known to have a great impact of nutrients enrichment on continental water resources. In south-West of France (Gascogne region), water resource are essentially surface water and shallow aquifer. Nitrogen dynamic in river is complex and highly variable throughout season and year, depending on hydrology, landuse, removal in stream. In this context, agricultural impacts on nitrogen concentration are a matter of concern for agricultural decision-maker. In order to introduce sustainable land use concepts in this hilly, clayey and agricultural shallow soil context, the hydrological simulation model SWAT2005 has been tested as a valuable tool to evaluate the consequences of such land use changes on water and nutrient balance components. This semi-distributed hydrological model coupled with agronomical model EPIC is able to simulate the impact of each agricultural landuse at the outlet of the Save catchment (1100 km2). Hydrological parameters model are calibrated based on 14-year historical record (1994-2008). Nitrogen losses have been measured during 2 years (2006-2008) at the outlet and are used to validate the model calibration. Agricultural data at communal scale coupled with Spot image analyses have been used to evaluate agricultural distribution and pressure in SWAT. The aim of this modelling exercise is to simulate nitrogen cycle in whole agricultural Hydrological Response Units (HRU), depending on plant growth and culture rotation, to simulate accurately nitrate load in river. The ability of SWAT to reproduce nitrogen transfert and transformation at this scale and in this agricultural context will be evaluated by a discussion of importance of each nitrogen cycle process in nitrogen losses. SWAT could be a useful tool to test agricultural scenario to improve the nitrogen management in river.

  8. Simultaneous observation of seasonal variations of beryllium-7 and typical POPs in near-surface atmospheric aerosols in Guangzhou, China

    Science.gov (United States)

    Pan, Jing; Yang, Yong-Liang; Zhang, Gan; Shi, Jing-Lei; Zhu, Xiao-Hua; Li, Yong; Yu, Han-Qing

    2011-07-01

    Near-surface atmospheric aerosol samples were collected at the sampling frequency of 2-3 d per week for one year from August 2006 to August 2007 at a low latitude station in Tianhe District, Guangzhou, Guangdong Province of southern China. The samples were analyzed for cosmogenic nuclide 7Be and persistent organic pollutants, i.e. organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). The annual average 7Be concentration was 2.59 mBq m -3, with the maximum occurred in May (8.45 mBq m -3) and minimum in late August and early September (0.07 mBq m -3). Winter and spring were the seasons in which the 7Be concentrations were high while summer and autumn were the lower 7Be seasons. Spring peaks in 7Be in the near-surface atmospheric aerosols may have associated with the "spring leak maximum" episode. The annual average ∑OCPs concentration was 345.6 pg m -3, ∑ 33PCBs 317.6 pg m -3, and ∑ 31PBDEs 609.0 pg m -3. The variation trends in the time-series of 7Be, OCPs, PCBs, and PBDEs in near-surface atmospheric aerosol showed both common features and differences. Significant correlations ( R2 = 0.957 and 0.811. respectively, p = 0.01) were observed between the monthly average 7Be concentrations and those of ∑PCBs and ∑PBDEs in summer, autumn, and early winter. The difference between the seasonal variation features of OCPs and PCBs (and PBDEs) could be attributed to the different source functions and physical-chemical properties which could control the behaviors of these compounds in air-aerosol partitions as well as atmospheric transport.

  9. Candida albicans CUG mistranslation is a mechanism to create cell surface variation.

    Science.gov (United States)

    Miranda, Isabel; Silva-Dias, Ana; Rocha, Rita; Teixeira-Santos, Rita; Coelho, Carolina; Gonçalves, Teresa; Santos, Manuel A S; Pina-Vaz, Cidália; Solis, Norma V; Filler, Scott G; Rodrigues, Acácio G

    2013-08-30

    In the human fungal pathogen Candida albicans, the CUG codon is translated 97% of the time as serine and 3% of the time as leucine, which potentially originates an array of proteins resulting from the translation of a single gene. Genes encoding cell surface proteins are enriched in CUG codons; thus, CUG mistranslation may influence the interactions of the organism with the host. To investigate this, we compared a C. albicans strain that misincorporates 28% of leucine at CUGs with a wild-type parental strain. The first strain displayed increased adherence to inert and host molecules. In addition, it was less susceptible to phagocytosis by murine macrophages, probably due to reduced exposure of cell surface β-glucans. To prove that these phenotypes occurred due to serine/leucine exchange, the C. albicans adhesin and invasin ALS3 was expressed in Saccharomyces cerevisiae in its two natural isoforms (Als3p-Leu and Als3p-Ser). The cells with heterologous expression of Als3p-Leu showed increased adherence to host substrates and flocculation. We propose that CUG mistranslation has been maintained during the evolution of C. albicans due to its potential to generate cell surface variability, which significantly alters fungus-host interactions. The translation of genetic information into proteins is a highly accurate cellular process. In the human fungal pathogen Candida albicans, a unique mistranslation event involving the CUG codon occurs. The CUG codon is mainly translated as serine but can also be translated as leucine. Leucine and serine are two biochemically distinct amino acids, hydrophobic and hydrophilic, respectively. The increased rate of leucine incorporation at CUG decoding triggers C. albicans virulence attributes, such as morphogenesis, phenotypic switching, and adhesion. Here, we show that CUG mistranslation masks the fungal cell wall molecule β-glucan that is normally recognized by the host immune system, delaying its response. Furthermore, we demonstrate

  10. Understanding Long-Term Variations in Surface Ozone in United States (U.S. National Parks

    Directory of Open Access Journals (Sweden)

    Deborah McGlynn

    2018-03-01

    Full Text Available Long-term surface ozone observations at 25 National Park Service sites across the United States were analyzed for processes on varying time scales using a time scale decomposition technique, the Ensemble Empirical Mode Decomposition (EEMD. Time scales of interest include the seasonal cycle, large-scale climate oscillations, and long-term (>10 years trends. Emission reductions were found to have a greater impact on sites that are nearest major urban areas. Multidecadal trends in surface ozone were increasing at a rate of 0.07 to 0.37 ppbv year−1 before 2004 and decreasing at a rate of −0.08 to −0.60 ppbv year−1 after 2004 for sites in the East, Southern California, and Northwestern Washington. Sites in the Intermountain West did not experience a reversal of trends from positive to negative until the mid- to late 2000s. The magnitude of the annual amplitude (=annual maximum–minimum decreased at eight sites, two in the West, two in the Intermountain West, and four in the East, by 5–20 ppbv and significantly increased at three sites; one in Alaska, one in the West, and one in the Intermountain West, by 3–4 ppbv. Stronger decreases in the annual amplitude occurred at a greater proportion of sites in the East (4/6 sites than in the West/Intermountain West (4/19 sites. The date of annual maximums and/or minimums has changed at 12 sites, occurring 10–60 days earlier in the year. There appeared to be a link between the timing of the annual maximum and the decrease in the annual amplitude, which was hypothesized to be related to a decrease in ozone titration resulting from NOx emission reductions. Furthermore, it was found that a phase shift of the Pacific Decadal Oscillation (PDO, from positive to negative, in 1998–1999 resulted in increased occurrences of La Niña-like conditions. This shift had the effect of directing more polluted air masses from East Asia to higher latitudes over the North American continent. The change in the

  11. Variation in glyphosate and AMPA concentrations of surface water and groundwater

    Science.gov (United States)

    Caprile, Ana Clara; Aparicio, Virginia; Sasal, Carolina; Andriulo, Enrique

    2017-04-01

    The presence of pesticides in various environmental matrices indicate that the soil's ability to function as a bio-physical-chemical reactor is declining. As it operates as an interface between air and water, it causes a negative impact on these two vital resources. Currently, the pampa agriculture is simplified with a marked tendency towards spring-summer crops, where the main crops are RR soybean and corn. Herbicides are neither retained nor degraded in the soil, which results in polluted groundwater and surface waters. The objectives of this study were: a) to verify the presence of glyphosate and aminomethylphosphonic acid (AMPA) in Pergamino stream (a typical representative of the most productive agricultural region of Argentina) under different land use and to detect if in the detections there was a space-time pattern, and b) to verify the detection of these molecules in groundwater of the upper same basin under exclusively rural land use. Surface stream was sampling in six sites (five under rural land use and one under urban-industrial land use) at a rate of one sample by spring, summer and winter seasons (2010-2013, 54 total samples). Groundwater glyphosate and AMPA concentrations were determined in 24 piezometers constructed at two positions of the landscape, across the groundwater flow direction, sampled at two sampling dates (2010 and 2012, 45 total samples). In surface water, glyphosate and AMPA were detected in 54 and 69% of the samples analyzed, respectively. The median concentrations were 0.9 and 0.8 µg L-1 for glyphosate and AMPA and maximal concentrations 258 and 5865 µg L-1, respectively. The sampling site under urban-industrial land use had abnormally high concentrations of glyphosate in the spring (attributed to point pollution), a fact that not allowed to see differences in the remaining sampling times under different land uses. AMPA concentrations under urban-industrial land use were high and higher than rural land use in 3 studied seasons

  12. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects

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    Liu Cao

    2017-01-01

    Full Text Available The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF magnetic stimulation on surface electromyography (SEMG signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject’s deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS, median frequency (MDF, and sample entropy (SampEn, were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant (p0.05. In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p<0.001 and MDF and SampEn were significantly smaller (all p<0.001.

  13. Effects of Force Load, Muscle Fatigue, and Magnetic Stimulation on Surface Electromyography during Side Arm Lateral Raise Task: A Preliminary Study with Healthy Subjects.

    Science.gov (United States)

    Cao, Liu; Wang, Ying; Hao, Dongmei; Rong, Yao; Yang, Lin; Zhang, Song; Zheng, Dingchang

    2017-01-01

    The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue, and extremely low-frequency (ELF) magnetic stimulation on surface electromyography (SEMG) signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI ActiveTwo system during side lateral raise task (with the right arm 90 degrees away from the body) with three different loads on the forearm (0 kg, 1 kg, and 3 kg; their order was randomized between subjects). The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as nonfatigue status and the last 10 s before the subject was exhausted was regarded as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, and this time the ELF magnetic stimulation was applied to the subject's deltoid muscle during the five-minute rest period. Three commonly used SEMG features, root mean square (RMS), median frequency (MDF), and sample entropy (SampEn), were analyzed and compared between different loads, nonfatigue/fatigue status, and ELF stimulation and no stimulation. Variance analysis results showed that the effect of force load on RMS was significant ( p 0.05). In comparison with nonfatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p < 0.001) and MDF and SampEn were significantly smaller (all p < 0.001).

  14. Variations in surface roughness of seven orthodontic archwires: an SEM-profilometry study

    Science.gov (United States)

    Rakhshan, Vahid; Pousti, Maryam; Rahimi, Hajir; Shariati, Mahsa; Aghamohamadi, Bahareh

    2012-01-01

    Objective The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. Methods This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (α wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 ± 915 A°, 1,378 ± 372 A°, 2,444 ± 369 A°, and 5,242 ± 2,832 A°, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 ± 210 A°, 1,831 ± 1,156 A°, and 4,018 ± 2,214 A°, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. Conclusions The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires. PMID:23112943

  15. Modelling the variation of land surface temperature as determinant of risk of heat-related health events

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    Goudreau Sophie

    2011-01-01

    Full Text Available Abstract Background The evaluation of exposure to ambient temperatures in epidemiological studies has generally been based on records from meteorological stations which may not adequately represent local temperature variability. Here we propose a spatially explicit model to estimate local exposure to temperatures of large populations under various meteorological conditions based on satellite and meteorological data. Methods A general linear model was used to estimate surface temperatures using 15 LANDSAT 5 and LANDSAT 7 images for Quebec Province, Canada between 1987 and 2002 and spanning the months of June to August. The images encompassed both rural and urban landscapes and predictors included: meteorological records of temperature and wind speed, distance to major water bodies, Normalized Differential Vegetation Index (NDVI, land cover (built and bare land, water, or vegetation, latitude, longitude, and week of the year. Results The model explained 77% of the variance in surface temperature, accounting for both temporal and spatial variations. The standard error of estimates was 1.42°C. Land cover and NDVI were strong predictors of surface temperature. Conclusions This study suggests that a statistical approach to estimating surface temperature incorporating both spatially explicit satellite data and time-varying meteorological data may be relevant to assessing exposure to heat during the warm season in the Quebec. By allowing the estimation of space- and time-specific surface temperatures, this model may also be used to assess the possible impacts of land use changes under various meteorological conditions. It can be applied to assess heat exposure within a large population and at relatively fine-grained scale. It may be used to evaluate the acute health effect of heat exposure over long time frames. The method proposed here could be replicated in other areas around the globe for which satellite data and meteorological data is available.

  16. Modelling the variation of land surface temperature as determinant of risk of heat-related health events.

    Science.gov (United States)

    Kestens, Yan; Brand, Allan; Fournier, Michel; Goudreau, Sophie; Kosatsky, Tom; Maloley, Matthew; Smargiassi, Audrey

    2011-01-21

    The evaluation of exposure to ambient temperatures in epidemiological studies has generally been based on records from meteorological stations which may not adequately represent local temperature variability. Here we propose a spatially explicit model to estimate local exposure to temperatures of large populations under various meteorological conditions based on satellite and meteorological data. A general linear model was used to estimate surface temperatures using 15 LANDSAT 5 and LANDSAT 7 images for Quebec Province, Canada between 1987 and 2002 and spanning the months of June to August. The images encompassed both rural and urban landscapes and predictors included: meteorological records of temperature and wind speed, distance to major water bodies, Normalized Differential Vegetation Index (NDVI), land cover (built and bare land, water, or vegetation), latitude, longitude, and week of the year. The model explained 77% of the variance in surface temperature, accounting for both temporal and spatial variations. The standard error of estimates was 1.42°C. Land cover and NDVI were strong predictors of surface temperature. This study suggests that a statistical approach to estimating surface temperature incorporating both spatially explicit satellite data and time-varying meteorological data may be relevant to assessing exposure to heat during the warm season in the Quebec. By allowing the estimation of space- and time-specific surface temperatures, this model may also be used to assess the possible impacts of land use changes under various meteorological conditions. It can be applied to assess heat exposure within a large population and at relatively fine-grained scale. It may be used to evaluate the acute health effect of heat exposure over long time frames. The method proposed here could be replicated in other areas around the globe for which satellite data and meteorological data is available.

  17. Reach-scale variation surface water quality in a reticular canal system in the lower Yangtze River Delta region, China.

    Science.gov (United States)

    Griffiths, James Andrew; Chan, Faith Ka Shun; Zhu, Fangfang; Wang, Vickie; Higgitt, David Laurence

    2017-07-01

    The aim of this research was to assess the spatial and temporal distribution of surface water pollution within a reticular canal system typical of those found in the lower Yangtze River Delta (YRD). For this purpose, surface water quality data was collected from a drainage canal that bisected the southeast district of Ningbo Municipality (Zhejiang) from 2013 to 2015. The sampling transect was designed to represent the change in land-use from the agriculture dominated rural hinterland, to the predominantly urban city-centre. To calculate the representative land-use fraction of each sampling location, the contributing area was defined using an uni-directional 1 km vector line-buffer around the 'upstream' section of canal. The spatial and temporal variation of EC, DO, NH 3 and turbidity indicated a measureable difference between the urban and rural sections of the channel. Water quality indicators were most sensitive to urban and parkland land-use types. The study yielded an increased spatial resolution to knowledge of water-quality variability in the urban environment compared to previous studies within the YRD region. The results were used to make recommendations for the development of an effective long-term strategy for the improvement in surface water quality in this region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Late Holocene variations in Pacific surface circulation and biogeochemistry inferred from proteinaceous deep-sea corals

    Science.gov (United States)

    Guilderson, T. P.; McCarthy, M. D.; Dunbar, R. B.; Englebrecht, A.; Roark, E. B.

    2013-09-01

    δ15N and δ13C data obtained from samples of proteinaceous deep-sea corals collected from the North Pacific Subtropical Gyre (Hawaiian Archipelago) and the central equatorial Pacific (Line Islands) document multidecadal to century-scale variability in the isotopic composition of surface-produced particulate organic matter exported to the deep sea. Comparison of the δ13C data, where Line Islands samples are 0.6‰ more positive than the Hawaiian samples, supports the contention that the North Pacific Subtropical Gyre is more efficient than the tropical upwelling system at trapping and/or recycling nutrients within the mixed layer. δ15N values from the Line Islands samples are also more positive than those from the central gyre, and within the Hawaiian samples there is a gradient with more positive δ15N values in samples from the main Hawaiian Islands versus the French Frigate Shoals in the Northwestern Hawaiian Islands. The gradient in the Hawaiian samples likely reflects the relative importance of algal acquisition of metabolic N via dissolved seawater nitrate uptake versus nitrogen fixation. The Hawaiian sample set also exhibits a strong decrease in δ15N values from the mid-Holocene to present. We hypothesize that this decrease is most likely the result of decreasing trade winds, and possibly a commensurate decrease in entrainment of more positive δ15N-NO3 subthermocline water masses.

  19. Establishing geochemical background variation and threshold values for 59 elements in Australian surface soil.

    Science.gov (United States)

    Reimann, Clemens; de Caritat, Patrice

    2017-02-01

    During the National Geochemical Survey of Australia over 1300 top (0-10cm depth) and bottom (~60-80cm depth) sediment samples (including ~10% field duplicates) were collected from the outlet of 1186 catchments covering 81% of the continent at an average sample density of 1 site/5200km 2 . The Australian surface soil. Different methods of obtaining geochemical threshold values, which differentiate between background and those samples with unusually high element concentrations and requiring attention, are presented and compared to Western Australia's 'ecological investigation levels' (EILs) established for 14 PTEs. For Mn and V these EILs are so low that an unrealistically large proportion (~24%) of the sampled sites would need investigation in Australia. For the 12 remaining elements (As, Ba, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sn and Zn) few sample sites require investigation and as most of these are located far from human activity centres, they potentially suggest either minor local contamination or mineral exploration potential rather than pollution. No major diffuse source of contamination by PTEs affects Australian soil at the continental scale. Of the statistical methods used to establish geochemical threshold values, the most pertinent results come from identifying breaks in cumulative probability distributions, the Tukey inner fence and the 98th percentile. Geochemical threshold values for 59 elements, including emerging 'high-tech' critical elements such as lanthanides, Be, Ga or Ge, for which no EILs currently exist, are presented. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  20. Late Holocene variations in Pacific surface circulation and biogeochemistry inferred from proteinaceous deep-sea corals

    Directory of Open Access Journals (Sweden)

    T. P. Guilderson

    2013-09-01

    Full Text Available δ15N and δ13C data obtained from samples of proteinaceous deep-sea corals collected from the North Pacific Subtropical Gyre (Hawaiian Archipelago and the central equatorial Pacific (Line Islands document multidecadal to century-scale variability in the isotopic composition of surface-produced particulate organic matter exported to the deep sea. Comparison of the δ13C data, where Line Islands samples are 0.6‰ more positive than the Hawaiian samples, supports the contention that the North Pacific Subtropical Gyre is more efficient than the tropical upwelling system at trapping and/or recycling nutrients within the mixed layer. δ15N values from the Line Islands samples are also more positive than those from the central gyre, and within the Hawaiian samples there is a gradient with more positive δ15N values in samples from the main Hawaiian Islands versus the French Frigate Shoals in the Northwestern Hawaiian Islands. The gradient in the Hawaiian samples likely reflects the relative importance of algal acquisition of metabolic N via dissolved seawater nitrate uptake versus nitrogen fixation. The Hawaiian sample set also exhibits a strong decrease in δ15N values from the mid-Holocene to present. We hypothesize that this decrease is most likely the result of decreasing trade winds, and possibly a commensurate decrease in entrainment of more positive δ15N-NO3 subthermocline water masses.

  1. A GIS Approach to Wind,SST(Sea Surface Temperature) and CHL(Chlorophyll) variations in the Caspian Sea

    Science.gov (United States)

    Mirkhalili, Seyedhamzeh

    2016-07-01

    Chlorophyll is an extremely important bio-molecule, critical in photosynthesis, which allows plants to absorb energy from light. At the base of the ocean food web are single-celled algae and other plant-like organisms known as Phytoplankton. Like plants on land, Phytoplankton use chlorophyll and other light-harvesting pigments to carry out photosynthesis. Where Phytoplankton grow depends on available sunlight, temperature, and nutrient levels. In this research a GIS Approach using ARCGIS software and QuikSCAT satellite data was applied to visualize WIND,SST(Sea Surface Temperature) and CHL(Chlorophyll) variations in the Caspian Sea.Results indicate that increase in chlorophyll concentration in coastal areas is primarily driven by terrestrial nutrients and does not imply that warmer SST will lead to an increase in chlorophyll concentration and consequently Phytoplankton abundance.

  2. A Torque Error Compensation Algorithm for Surface Mounted Permanent Magnet Synchronous Machines with Respect to Magnet Temperature Variations

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    Chang-Seok Park

    2017-09-01

    Full Text Available This paper presents a torque error compensation algorithm for a surface mounted permanent magnet synchronous machine (SPMSM through real time permanent magnet (PM flux linkage estimation at various temperature conditions from medium to rated speed. As known, the PM flux linkage in SPMSMs varies with the thermal conditions. Since a maximum torque per ampere look up table, a control method used for copper loss minimization, is developed based on estimated PM flux linkage, variation of PM flux linkage results in undesired torque development of SPMSM drives. In this paper, PM flux linkage is estimated through a stator flux linkage observer and the torque error is compensated in real time using the estimated PM flux linkage. In this paper, the proposed torque error compensation algorithm is verified in simulation and experiment.

  3. Causes of global mean surface temperature slowdowns, trends and variations from months to a century, 1891-2015

    Science.gov (United States)

    Folland, C. K.; Boucher, O.; Colman, A.; Parker, D. E.

    2017-12-01

    The recent slowdown in the warming of global mean surface temperature (GST) has highlighted the influences of natural variability. This talk discusses reconstructions of the variations of GST down to the monthly time scale since 1891 using monthly forcing data. We show that most of the variations in annual, and to some extent sub-annual, GST since 1891 can be reproduced skillfully from known forcing factors external and internal to the climate system. This includes the slowdown in warming over about 1998-2013 where reconstruction skill is particularly high down to the multi-monthly time scale. The relative contributions of the several key forcing factors to GST continually vary, but most of the net warming since 1891 is reconstructed to be attributable to the net forcing due to increasing greenhouse gases and anthropogenic aerosols. Separate analyses are carried out for three periods of GST slowdown:- 1896-1910, 1941-1976, together with 1998-2013 and some of its sub periods. We also study two periods where strong warming occurred, 1911-1940 and 1977-1997. Comparisons are made with the skill of average GST provided by 40 CMIP5 models. In the recent 1998-2013 slowdown, TSI forcing appears to have caused significant cooling, particularly over 2001-2010. This is additional to well documented cooling effects of an increased frequency of La Nina events, a negative Interdecadal Pacific Oscillation and some increases in volcanic forcing. Although there are short-term features of the GST curve since 1891 that cannot be fully explained, the most serious disagreements between the reconstructions and observations occur in the Second World War, especially in 1944-1945. Here observed near worldwide SSTs may be biased significantly too warm. Despite this, our generally high reconstruction skill is consistent with a good understanding of the multiple causes of observed GST variations and the general veracity of the GST record since 1891.

  4. The variation in visibility and its relationship with surface wind speed in China from 1960 to 2009

    Science.gov (United States)

    Sun, Tianze; Che, Huizheng; Wu, Jian; Wang, Hong; Wang, Yaqiang; Zhang, Xiaoye

    2018-01-01

    This study used daily visibility and surface wind speed observational data over the 50-year period from 1960 to 2009, from 464 national meteorological stations in China, to examine the relationship between these two variables. Specifically, using the statistical methods of empirical orthogonal function (EOF) analysis and wavelet analysis, the data were processed into anomaly data to study their spatial and temporal distributions and the characteristics of each pattern's periodicity after EOF analysis of the whole country's visibility and surface wind speed. Correlation analysis and composite analysis were then used to elucidate the relationship between the two variables on different time scales. The results showed a gradual reduction in visibility nationally, with the nine-point moving mean implying decadal variability of the visibility with a downward trend. However, an irregular oscillation was found for the inter-annual variability of visibility. For the anomaly series of visibility during the 50-year period, a long-period oscillation of around 32 years was apparent. Up until the 1990s, there was an approximate 16-year medium-term oscillation period, whereas, after the 1990s, an approximate 8-year oscillation period was generated. In terms of high correlation between the two variables, for the decadal variability, the changes in visibility and surface wind speed at this time scale were almost in agreement. Meanwhile, with respect to the serious pollution in the Yangtze River Delta Economic Zone, the correlation between the two variables was reasonably high, suggesting that surface wind had a significant influence on the scattering of aerosol particles. However, in the Sichuan Basin, the correlation was relatively low, possibly on account of its landscape limiting the variation of wind speed.

  5. Mechanistic Investigation into the Selective Anticancer Cytotoxicity and Immune System Response of Surface-Functionalized, Dichloroacetate-Loaded, UiO-66 Nanoparticles.

    Science.gov (United States)

    Abánades Lázaro, Isabel; Haddad, Salame; Rodrigo-Muñoz, José M; Orellana-Tavra, Claudia; Del Pozo, Victoria; Fairen-Jimenez, David; Forgan, Ross S

    2018-02-14

    The high drug-loading and excellent biocompatibilities of metal-organic frameworks (MOFs) have led to their application as drug-delivery systems (DDSs). Nanoparticle surface chemistry dominates both biostability and dispersion of DDSs while governing their interactions with biological systems, cellular and/or tissue targeting, and cellular internalization, leading to a requirement for versatile and reproducible surface functionalization protocols. Herein, we explore not only the effect of introducing different surface functionalities to the biocompatible Zr-MOF UiO-66 but also the efficacy of three surface modification protocols: (i) direct attachment of biomolecules [folic acid (FA) and biotin (Biot)] introduced as modulators for UiO-66 synthesis, (ii) our previously reported "click-modulation" approach to covalently attach polymers [poly(ethylene glycol) (PEG), poly-l-lactide, and poly-N-isopropylacrylamide] to the surface of UiO-66 through click chemistry, and (iii) surface ligand exchange to postsynthetically coordinate FA, Biot, and heparin to UiO-66. The innovative use of a small molecule with metabolic anticancer activity, dichloroacetate (DCA), as a modulator during synthesis is described, and it is found to be compatible with all three protocols, yielding surface-coated, DCA-loaded (10-20 w/w %) nano-MOFs (70-170 nm). External surface modification generally enhances the stability and colloidal dispersion of UiO-66. Cellular internalization routes and efficiencies of UiO-66 by HeLa cervical cancer cells can be tuned by surface chemistry, and anticancer cytotoxicity of DCA-loaded MOFs correlates with the endocytosis efficiency and mechanisms. The MOFs with the most promising coatings (FA, PEG, poly-l-lactide, and poly-N-isopropylacrylamide) were extensively tested for selectivity of anticancer cytotoxicity against MCF-7 breast cancer cells and HEK293 healthy kidney cells as well as for cell proliferation and reactive oxygen species production against J774

  6. Effects of strong earthquakes in variations of electrical and meteorological parameters of the near-surface atmosphere in Kamchatka region

    Science.gov (United States)

    Smirnov, S. E.; Mikhailova, G. A.; Mikhailov, Yu. M.; Kapustina, O. V.

    2017-09-01

    The diurnal variations in electrical (quasistatic electric field and electrical conductivity) and meteorological (temperature, pressure, relative humidity of the atmosphere, and wind speed) parameters, measured simultaneously before strong earthquakes in Kamchatka region (November 15, 2006, M = 8.3; January 13, 2007, M = 8.1; January 30, 2016, M = 7.2), are studied for the first time in detail. It is found that a successively anomalous increase in temperature, despite the negative regular trend in these winter months, was observed in the period of six-seven days before the occurrences of earthquakes. An anomalous temperature increase led to the formation of "winter thunderstorm" conditions in the near-surface atmosphere of Kamchatka region, which was manifested in the appearance of an anomalous, type 2 electrical signal, the amplification of and intensive variations in electrical conductivity, heavy precipitation (snow showers), high relative humidity of air, storm winds, and pressure changes. With the weak flow of natural heat radiation in this season, the observed dynamics of electric and meteorological processes can likely be explained by the appearance of an additional heat source of seismic nature.

  7. Spatial variations of prokaryotic communities in surface water from India Ocean to Chinese marginal seas and their underlining environmental determinants

    Directory of Open Access Journals (Sweden)

    Xiaowei eZheng

    2016-02-01

    Full Text Available To illustrate the biogeographic patterns of prokaryotic communities in surface sea water, 24 samples were systematically collected across a large distance from Indian Ocean to Chinese marginal seas, with an average distance of 453 km between two adjacent stations. A total of 841,364 quality reads was produced by the high throughput DNA sequencing of the 16S rRNA genes. Phylogenetic analysis showed that Proteobacteria were predominant in all samples, with Alphaproteobacteria and Gammaproteobacteria being the two most abundant components. Cyanobacteria represented the second largest fraction of the total quality reads, and mainly included Prochlorococcus and Synechococcus. The semi-closed marginal seas, including South China Sea (SCS and nearby regions, exhibited a transition in community composition between oceanic and coastal seas, based on the distribution patterns of Prochlorococcus and Synechococcus as well as a non-metric multidimensional scaling (NMDS analysis. Distinct clusters of prokaryotes from coastal and open seas, and from different water masses in Indian Ocean were obtained by Bray-Curtis dissimilarity analysis at the OTU level, revealing a clear spatial heterogeneity. The major environmental factors correlated with the community variation in this broad scale were identified as salinity, temperature and geographic distance. Community comparison among regions shows that anthropogenic contamination is another dominant factor in shaping the biogeographic patterns of the microorganisms. These results suggest that environmental factors involved in complex interactions between land and sea act synergistically in driving spatial variations in coastal areas.

  8. Limited variation in vaccine candidate Plasmodium falciparum Merozoite Surface Protein-6 over multiple transmission seasons

    Directory of Open Access Journals (Sweden)

    Branch OraLee H

    2010-05-01

    Full Text Available Abstract Background Plasmodium falciparum Merozoite Surface Protein-6 (PfMSP6 is a component of the complex proteinacious coat that surrounds P. falciparum merozoites. This location, and the presence of anti-PfMSP6 antibodies in P. falciparum-exposed individuals, makes PfMSP6 a potential blood stage vaccine target. However, genetic diversity has proven to be a major hurdle for vaccines targeting other blood stage P. falciparum antigens, and few endemic field studies assessing PfMSP6 gene diversity have been conducted. This study follows PfMSP6 diversity in the Peruvian Amazon from 2003 to 2006 and is the first longitudinal assessment of PfMSP6 sequence dynamics. Methods Parasite DNA was extracted from 506 distinct P. falciparum infections spanning the transmission seasons from 2003 to 2006 as part of the Malaria Immunology and Genetics in the Amazon (MIGIA cohort study near Iquitos, Peru. PfMSP6 was amplified from each sample using a nested PCR protocol, genotyped for allele class by agarose gel electrophoresis, and sequenced to detect diversity. Allele frequencies were analysed using JMP v.8.0.1.0 and correlated with clinical and epidemiological data collected as part of the MIGIA project. Results Both PfMSP6 allele classes, K1-like and 3D7-like, were detected at the study site, confirming that both are globally distributed. Allele frequencies varied significantly between transmission seasons, with 3D7-class alleles dominating and K1-class alleles nearly disappearing in 2005 and 2006. There was a significant association between allele class and village location (p-value = 0.0008, but no statistically significant association between allele class and age, sex, or symptom status. No intra-allele class sequence diversity was detected. Conclusions Both PfMSP6 allele classes are globally distributed, and this study shows that allele frequencies can fluctuate significantly between communities separated by only a few kilometres, and over time in the

  9. Spatial and temporal variation in pH, alkalinity and conductivity in surface runoff and groundwater for the Upper River Severn catchment

    Directory of Open Access Journals (Sweden)

    T. Hill

    1997-01-01

    Full Text Available Measurements of pH, alkalinity and electrical conductivity are used to examine the extent of the spatial and temporal variation in stream and ground water chemistry for the Upper Severn catchment, Plynlimon. Wide temporal variations in stream waters broadly reflect flow conditions and complex soil and ground water interactions but not soil type, land usage or geology. The results have major implications for the use of critical load analysis and the development and application of models in upland catchments. They point to the value of field measurements for assessing the environmental management of upland catchments, rather than the present use of over simplistic or inappropriate models.

  10. Postthaw survival of in vitro-produced bovine blastocysts loaded onto the inner surface of a plastic vitrification straw.

    Science.gov (United States)

    Ha, A-Na; Park, Han-Seul; Jin, Jong-In; Lee, Sang-Ho; Ko, Dae-Hwan; Lee, Dong-Suk; White, Kenneth L; Kong, Il-Keun

    2014-02-01

    In this study, we investigated whether vitrification of an embryo by attachment to the inner surface of a plastic straw, which requires a small volume of vitrification solution, improves the survival of thawed embryos. In vitro-produced Korean native cattle blastocysts were randomly assigned into four groups: (1) blastocysts attached to the inner surface of a plastic straw (aV); (2) blastocysts loaded into the column of a plastic straw (cV); (3) blastocysts directly dropped into liquid nitrogen (dV); and (4) nonvitrified blastocysts (control). The postthaw recovery rate did not significantly differ among the aV, dV, and cV groups (98.3% vs. 81.5% vs. 91.4%). The postthaw survival rate was greater in the control, aV, and dV groups than in the cV group (100%, 87.7%, and 81.8% vs. 26.4%, P < 0.05), but did not significantly differ among the control, aV, and dV groups. The total number of cells per blastocyst did not significantly differ among the groups (134.4 ± 38.9 in control vs. 114 ± 48.1 in aV, 105.6 ± 33.9 in dV, and 102 ± 35.1 in cV group). However, the number of apoptotic cells per blastocyst was higher in the dV and cV groups than in the control group (10.9 ± 9.6 and 14.5 ± 9.5 vs. 0.4 ± 1.4; P < 0.05), but did not significantly differ between the control and aV groups (0.4 ± 1.4 vs. 6.6 ± 9.5). In addition, the blastocoel of each blastocyst was left intact or was mechanically punctured to reduce its volume, and the blastocysts were then vitrified using the aV method. At 12 hours after thawing, the re-expansion rate did not significantly differ among the control, punctured aV, and nonpunctured aV groups (93.3% vs. 85.2% vs. 82.8%). However, at 24 hours after thawing, the hatching rate was greater in the control and punctured aV groups than in the nonpunctured aV group (75% and 62.9% vs. 37.1%; P < 0.05). The total number of cells per blastocyst was greater in the control group than in the nonpunctured aV group (143 ± 37.2 vs. 94.5 ± 18.6; P < 0

  11. [Wear intensity and surface roughness of microhybrid composite and ceramic occlusal veneers on premolars after the thermocycling and cyclic mechanical loading tests].

    Science.gov (United States)

    Zhang, H Y; Jiang, T; Cheng, M X; Zhang, Y W

    2018-02-18

    To evaluate the wear intensity and surface roughness of occlusal veneers on premolars made of microhybrid composite resin or two kinds of ceramics in vitro after the thermocycling and cyclic mechanical loading tests. In the study,24 fresh extracted human premolars without root canal treatment were prepared (cusps reduction of 1.5 mm in thickness to simulate middle to severe tooth wear, the inclinations of cusps were 20°). The prepared teeth were restored with occlusal veneers made of three different materials: microhybrid composite, heat-pressed lithium disilicate ceramic and computer-aided design/computer-aided manufacturing (CAD/CAM) lithium disilicate ceramic in the thickness of 1.5 mm. The occlusal veneers were cemented with resin cement. The specimens were fatigued using the thermocycling and cyclic mechanical loading tests after being stored in water for 72 h. The wear of specimens was measured using gypsum replicas and 3D laser scanner before and after the thermocycling and cyclic mechanical loading tests and the mean lost distance (mm) was used to indicate the level of wear. The surfaces of occlusal contact area were observed and the surface roughness was recorded using 3D laser scanning confocal microscope before and after the fatigue test. Differences between the groups were compared using ONE-way ANOVA(Pmechanical loading tests. The mean wear of microhybrid composite group, heat-pressed lithium disilicate ceramic group, and CAD/CAM lithium disilicate ceramic group was (-0.13±0.03) mm, (-0.05±0.01) mm and (-0.05±0.01) mm, the wear of microhybrid composite was significantly higher than the two ceramic groups(PCAD/CAM lithium disilicate ceramic (P=0.010). From the view of wear speed, microhybrid composite was significantly higher than the two kinds of ceramics, but it was similar to enamel when the opposing tooth was natural. The surface roughness before the themocycling and cyclic mechanical loading test of microhybrid composite was significantly

  12. A new multi-domain method based on an analytical control surface for linear and second-order mean drift wave loads on floating bodies

    Science.gov (United States)

    Liang, Hui; Chen, Xiaobo

    2017-10-01

    A novel multi-domain method based on an analytical control surface is proposed by combining the use of free-surface Green function and Rankine source function. A cylindrical control surface is introduced to subdivide the fluid domain into external and internal domains. Unlike the traditional domain decomposition strategy or multi-block method, the control surface here is not panelized, on which the velocity potential and normal velocity components are analytically expressed as a series of base functions composed of Laguerre function in vertical coordinate and Fourier series in the circumference. Free-surface Green function is applied in the external domain, and the boundary integral equation is constructed on the control surface in the sense of Galerkin collocation via integrating test functions orthogonal to base functions over the control surface. The external solution gives rise to the so-called Dirichlet-to-Neumann [DN2] and Neumann-to-Dirichlet [ND2] relations on the control surface. Irregular frequencies, which are only dependent on the radius of the control surface, are present in the external solution, and they are removed by extending the boundary integral equation to the interior free surface (circular disc) on which the null normal derivative of potential is imposed, and the dipole distribution is expressed as Fourier-Bessel expansion on the disc. In the internal domain, where the Rankine source function is adopted, new boundary integral equations are formulated. The point collocation is imposed over the body surface and free surface, while the collocation of the Galerkin type is applied on the control surface. The present method is valid in the computation of both linear and second-order mean drift wave loads. Furthermore, the second-order mean drift force based on the middle-field formulation can be calculated analytically by using the coefficients of the Fourier-Laguerre expansion.

  13. Safety and effectiveness of early loaded maxillary titanium implants with a novel nanostructured calcium-incorporated surface (Xpeed): 3-year results from a pilot multicenter randomised controlled trial.

    Science.gov (United States)

    Felice, Pietro; Grusovin, Maria Gabriella; Barausse, Carlo; Grandi, Giovanni; Esposito, Marco

    2015-01-01

    To evaluate clinical safety and effectiveness of a novel calcium-incorporated titanium implant surface (Xpeed, MegaGen Implant Co., Gyeongbuk, South Korea). Sixty patients were randomised to receive one to six implants in the maxilla with either calcium-incorporated (Xpeed) or control resorbable blasted media (RBM) surfaces, according to a parallel group design at two centres. Implants were submerged and exposed at three different endpoints in equal groups of 20 patients, each at 12, 10 and 8 weeks, respectively. Within 2 weeks, implants were functionally loaded with provisional or definitive prostheses. Outcome measures were prosthesis failures, implant failures, any complications and peri-implant marginal bone level changes. Thirty patients received 45 calcium-incorporated implants and 30 patients received 42 control titanium implants. Three years after loading four patients dropped-out from the Xpeed group and one from the RBM group. No prosthesis or implant failures occurred. There were no statistically significant differences between the groups for complications (P = 0.91; difference in proportions = 0.79 %; 95% CI -0.71 to 2.29) and mean marginal bone level changes (P = 0.88; mean difference = -0.02 mm; 95% CI -0.26 to 0.22). Both implant surfaces provided good clinical results and no significant difference was found when comparing titanium implants with a nanostructured calcium-incorporated surface versus implants with RBM surfaces.

  14. Year-round variations in the fluvial transport load of particulate 137Cs in a forested catchment affected by the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Takeshi Matsunaga; Takahiro Nakanishi; Mariko Atarashi-Andoh; Erina Takeuchi; Kotomi Muto; Katsunori Tsuduki; Syusaku Nishimura; Jun Koarashi; Shigeyoshi Otosaka; Tsutomu Sato

    2016-01-01

    Particulate 137 Cs was collected from stream water for 2 years to assess the long-term trend of 137 Cs discharge from a forest after the Fukushima Nuclear Power Plant accident. A seasonal increase in the fluvial transport load of particulate 137 Cs in suspended solids (SS) was observed in July-October when rainfall was abundant. The 137 Cs load was controlled by the SS load. This control was attributed to cesium affinity for phyllosilicate clay minerals as verified by the low extractability of particulate 137 Cs. These findings indicate the fluvial particulate 137 Cs load is significantly related to the climate and geomorphological features of Japan. (author)

  15. Evaluation And Characterization Of Trace Metals Contamination In The Surface Sediment Using Pollution Load Index PLI And Geo-Accumulation Index Igeo Of Ona River Western Nigeria

    Directory of Open Access Journals (Sweden)

    Andem

    2015-01-01

    Full Text Available Abstract Evaluation and Characterization of Trace Metal Contamination in the Surface Sediment Using Pollution Load Index PLI and Geo-accumulation Index Igeo Index of Ona River was conducted for six months. From the result of this study the mean values of lead ranged between 0.004 mgkg and 0.330 mgkg while the mean iron was highest 5.05 mgkg in station 4 and lowest 2.26 mgkg in station 5. The mean chromium value ranged from 0.007 mgkg station 1 and 2 to 0.021 mgkg station 3 and 4. The mean copper was highest 3.97 mgkg in station 1 and lowest 0.008 mgkg in station 2. Analysis of variance ANOVA revealed the same trend in spatial variation of these heavy metals. There was a significant difference P 0.05 in lead chromium and copper among the study sampling stations and insignificant difference P0.05 in iron among the study sampling station. The PLI values recorded for all the stations were below 1. Thus the sediment of the study stretch that Ona River is unpolluted. The Igeo values for chromium and iron fall in class 0 in all the five sampling stations indicating that there is no pollution from these metals in the Ona River sediments lead fall in class 3 in station 4indicating moderately to heavily contaminated condition and class 0in station 1 2 3 and 5 and copper fall in class 3 in station 4 and 5 in class 6 in station 3 indicating extremely contaminated condition. The Igeo values were consistent with those derived for PLI. All trace metals had concentrations below the EPA regulatory limits for sediment except iron. From the results of this study sediment quality reflects the impacts of anthropogenic activities on quality of the river. However the continuous build-up of the metal contaminants can be checked if relevant government agencies ensure strict compliant of industrial standards which stipulate treatment of industrial waste before discharging such contaminated effluentswastes into River. Therefore perpetual assessment is highly recommended

  16. Two or three machined vs roughened surface dental implants loaded immediately supporting total fixed prostheses: 1-year results from a randomised controlled trial.

    Science.gov (United States)

    Cannizzaro, Gioacchino; Gastaldi, Giorgio; Gherlone, Enrico; Vinci, Raffaele; Loi, Ignazio; Trullenque-Eriksson, Anna; Esposito, Marco

    To compare implants with machined vs roughened surfaces placed flapless in totally edentulous jaws and immediately restored with metal-resin screw-retained cross-arch prostheses. Mandibles were rehabilitated with two implants (Fixed-on-2 or Fo2) and maxillae with three implants (Fixed-on-3 or Fo3). Forty edentulous or to be rendered edentulous patients (20 in the mandible and 20 in the maxilla) were randomised to the machined group (20 patients: 10 mandibles and 10 maxillae) and to the roughened group (20 patients: 10 mandibles and 10 maxillae) according to a parallel group design. To be immediately loaded implants had to be inserted with a minimum torque of 60 Ncm. Outcome measures were prosthesis and implant failures, complications and peri-implant marginal bone level changes evaluated up to 1 year post-loading. Flaps were raised in four patients from the machined group. Four prostheses on machined implants and three on roughened implants were delayed for loading because a sufficient insertion torque was not obtained. There were no dropouts 1 year after loading. Two maxillary machined implants were lost in two patients (difference in proportions = 0.10; 95% CI = -0.03 to 0.23; P (Fisher's exact test) = 0.487); one maxillary Fo3 prosthesis on machined implants and one mandibular Fo2 prosthesis on roughened implants had to be remade (difference in proportions = 0; 95% CI = -0.14 to 0.14; P (Fisher's exact test) = 1.000). Five patients with machined implants had six complications vs seven patients who had eight complications at roughened implants (difference in proportions = -0.10; 95% CI = -0.38 to 0.18; P (Fisher's exact test) = 0.731). There were no statistically significant differences for implant failures, prosthetic failures or complications between groups. There were no statistically significant differences for marginal peri-implant bone levels between the two groups (estimate of the difference = -0.06 mm; 95% CI = -0.23 to 0.10; P (ANCOVA) = 0.445), with

  17. Response of surface buoy moorings in steady and wave flows

    Digital Repository Service at National Institute of Oceanography (India)

    Anand, N.M.; Nayak, B.U.; SanilKumar, V.

    A numerical model has been developed to evaluate the dynamics of surface buoy mooring systems under wave and current loading. System tension response and variation of tension in the mooring line at various depths have been evaluated for deep water...

  18. Spatial Variation, Pollution Assessment and Source Identification of Major Nutrients in Surface Sediments of Nansi Lake, China

    Directory of Open Access Journals (Sweden)

    Longfeng Wang

    2017-06-01

    Full Text Available Nansi Lake has been seriously affected by intensive anthropogenic activities in recent years. In this study, an extensive survey on spatial variation, pollution assessment as well as the possible sources identification of major nutrients (Total phosphorus: TP, Total nitrogen: TN, and Total organic carbon: TOC in the surface sediments of Nansi Lake was conducted. Results showed that the mean contents of TP, TN and TOC were 1.13-, 5.40- and 2.50- fold higher than their background values respectively. Most of the TN and TOC contents in the surface sediments of Nansi Lake were four times as high or higher and twice as high or higher than the background values except the Zhaoyang sub-lake, and the spatial distribution of TN and TOC contents were remarkably similar over a large area. Nearly all the TP contents in the surface sediments of Nansi Lake were all higher than its background values except most part of the Zhaoyang sub-lake. Based on the enrichment factor (EF and the organic pollution evaluation index (Org-index, TP, TOC and TN showed minor enrichment (1.13, minor enrichment (2.50 and moderately severe enrichment (5.40, respectively, and most part of the Dushan sub-lake and the vicinity of the Weishan island were in moderate or heavy sediments organic pollution, while the other parts were clean. Moreover, according to the results of multivariate statistical analysis, we deduced that anthropogenic TN and TOC were mainly came from industrial sources including enterprises distributed in Jining, Yanzhou and Zoucheng along with iron and steel industries distributed in the southern of the Weishan sub-lake, whereas TP mainly originated from runoff and soil erosion coming from agricultural lands located in Heze city and Weishan island, the local aquacultural activities as well as the domestic sewage discharge of Jining city.

  19. Analysis of pushing exercises: muscle activity and spine load while contrasting techniques on stable surfaces with a labile suspension strap training system.

    Science.gov (United States)

    McGill, Stuart M; Cannon, Jordan; Andersen, Jordan T

    2014-01-01

    Labile surfaces in the form of suspension straps are increasingly being used as a tool in resistance training programs. Pushing is a common functional activity of daily living and inherently part of a well-rounded training program. This study examined pushing exercises performed on stable surfaces and unstable suspension straps, specifically muscle activation levels and spine loads were quantified together with the influence of employing technique coaching. There were several main questions that this study sought to answer: Which exercises challenged particular muscles? What was the magnitude of the resulting spine load? How did stable and unstable surfaces differ? Did coaching influence the results? Fourteen men were recruited as part of a convenience sample (mean age, 21.1 ± 2.0 years; height, 1.77 ± 0.06 m; mean weight, 74.6 ± 7.8 kg). Data were processed and input to a sophisticated and anatomically detailed 3D model that used muscle activity and body segment kinematics to estimate muscle force-in this way, the model was sensitive to the individuals choice of motor control for each task; muscle forces and linked segment joint loads were used to calculate spine loads. Exercises were performed using stable surfaces for hand/feet contact and repeated where possible with labile suspension straps. Speed of movement was standardized across participants with the use of a metronome for each exercise. There were gradations of muscle activity and spine load characteristics to every task. In general, the instability associated with the labile exercises required greater torso muscle activity than when performed on stable surfaces. Throughout the duration of an exercise, there was a range of compression; the TRX push-up ranged from 1,653 to 2,128.14 N, whereas the standard push-up had a range from 1,233.75 to 1,530.06 N. There was no significant effect of exercise on spine compression (F(4,60) = 0.86, p = 0.495). Interestingly, a standard push-up showed significantly

  20. High cloud variations with surface temperature from 2002 to 2015: Contributions to atmospheric radiative cooling rate and precipitation changes

    Science.gov (United States)

    Liu, Run; Liou, Kuo-Nan; Su, Hui; Gu, Yu; Zhao, Bin; Jiang, Jonathan H.; Liu, Shaw Chen

    2017-05-01

    The global mean precipitation is largely constrained by atmospheric radiative cooling rates (Qr), which are sensitive to changes in high cloud fraction. We investigate variations of high cloud fraction with surface temperature (Ts) from July 2002 to June 2015 and compute their radiative effects on Qr using the Fu-Liou-Gu plane-parallel radiation model. We find that the tropical mean (30°S-30°N) high cloud fraction decreases with increasing Ts at a rate of about -1.0 ± 0.34% K-1 from 2002 to 2015, which leads to an enhanced atmospheric cooling around 0.86 W m-2 K-1. On the other hand, the northern midlatitudes (30°N-60°N) high cloud fraction increases with surface warming at a rate of 1.85 ± 0.65% K-1 and the near-global mean (60°S-60°N) high cloud fraction shows a statistically insignificant decreasing trend with increasing Ts over the analysis period. Dividing high clouds into cirrus, cirrostratus, and deep convective clouds, we find that cirrus cloud fraction increases with surface warming at a rate of 0.32 ± 0.11% K-1 (0.01 ± 0.17% K-1) for the near-global mean (tropical mean), while cirrostratus and deep convective clouds decrease with surface warming at a rate of -0.02 ± 0.18% K-1 and -0.33 ± 0.18% K-1 for the near-global mean and -0.64 ± 0.23% K-1 and -0.37 ± 0.13% K-1 for the tropical mean, respectively. High cloud fraction response to feedback to Ts accounts for approximately 1.9 ± 0.7% and 16.0 ± 6.1% of the increase in precipitation per unit surface warming over the period of 2002-2015 for the near-global mean and the tropical mean, respectively.

  1. Early Bone Formation around Immediately Loaded Transitional Implants Inserted in the Human Posterior Maxilla: The Effects of Fixture Design and Surface

    Directory of Open Access Journals (Sweden)

    Carlo Mangano

    2017-01-01

    Full Text Available Aim. To evaluate the effects of fixture design and surface on the early bone formation around immediately loaded implants inserted in the human posterior maxilla. Materials and Methods. Ten totally edentulous subjects received two transitional implants: one tapered implant with knife-edge threads/nanostructured calcium-incorporated surface (test: Anyridge®, Megagen, Gyeongbuk, South Korea and one cylindrical implant with self-tapping threads/sandblasted surface (control: EZPlus®, Megagen. The implants were placed according to a split-mouth design and immediately loaded to support an interim complete denture; after 8 weeks, they were removed for histologic/histomorphometric analysis. The bone-to-implant contact (BIC% and the bone density (BD% were calculated. The Wilcoxon test was used to evaluate the differences. Results. With test implants, a mean BIC% and BD% of 35.9 (±9.1 and 31.8 (±7.5 were found. With control implants, a mean BIC% and BD% of 29.9 (±7.6 and 32.5 (±3.9 were found. The mean BIC% was higher with test implants, but this difference was not significant (p=0.16. Similar BD% were found in the two groups (p=0.9. Conclusions. In the posterior maxilla, under immediate loading conditions, implants with a knife-edge thread design/nanostructured calcium-incorporated surface seem to increase the peri-implant endosseous healing properties, when compared to implants with self-tapping thread design/sandblasted surface.

  2. Early Bone Formation around Immediately Loaded Transitional Implants Inserted in the Human Posterior Maxilla: The Effects of Fixture Design and Surface

    Science.gov (United States)

    Pires, Jefferson Trabach; Luongo, Giuseppe; Piattelli, Adriano

    2017-01-01

    Aim. To evaluate the effects of fixture design and surface on the early bone formation around immediately loaded implants inserted in the human posterior maxilla. Materials and Methods. Ten totally edentulous subjects received two transitional implants: one tapered implant with knife-edge threads/nanostructured calcium-incorporated surface (test: Anyridge®, Megagen, Gyeongbuk, South Korea) and one cylindrical implant with self-tapping threads/sandblasted surface (control: EZPlus®, Megagen). The implants were placed according to a split-mouth design and immediately loaded to support an interim complete denture; after 8 weeks, they were removed for histologic/histomorphometric analysis. The bone-to-implant contact (BIC%) and the bone density (BD%) were calculated. The Wilcoxon test was used to evaluate the differences. Results. With test implants, a mean BIC% and BD% of 35.9 (±9.1) and 31.8 (±7.5) were found. With control implants, a mean BIC% and BD% of 29.9 (±7.6) and 32.5 (±3.9) were found. The mean BIC% was higher with test implants, but this difference was not significant (p = 0.16). Similar BD% were found in the two groups (p = 0.9). Conclusions. In the posterior maxilla, under immediate loading conditions, implants with a knife-edge thread design/nanostructured calcium-incorporated surface seem to increase the peri-implant endosseous healing properties, when compared to implants with self-tapping thread design/sandblasted surface. PMID:28280731

  3. Urban and agricultural contribution of annual loads of glyphosate and AMPA towards surface waters at the Orge River catchment scale (France)

    Science.gov (United States)

    Botta, Fabrizio; Chevreuil, Marc; Blanchoud, Hélène

    2010-05-01

    The general use of pesticides in the Orge Basin, located in the southern part of the Paris suburb (France), is damaging surface water quality. Consequently, an increase in the water supply costs is registered by the water supply agencies that are situated downstream the Orge confluence with the Seine River. In this catchment, high uses of glyphosate are registered for fallow fields (upstream part) and for roadway weed control (downstream part). The proportion of glyphosate coming from these two zones was not well known, along with the double source of its metabolite AMPA originated from the degradation of some detergent phosphonates. The aim of this work was firstly to identify the potential sources of glyphosate and AMPA in urban sectors (such as sewerage system inputs) and in agricultural areas and to quantify the origins of urban pesticides pathways towards surface waters at the basin scale. The new approach of this project was to collect information at three different scales to establish a first step of modeling. At the basin scale, 1 year of surface water monitoring at the outlet of the Orge River was useful to establish the inputs towards the Seine River. At the urban catchment scale, the investigations have permitted to record glyphosate and AMPA loads transferred by storm waters and by wastewaters. Loads were estimated during and out of application calendar, in different hydrological conditions such as rainfall with high intensity or dry conditions. Impact of WWTP on surface water was also demonstrated. The third phase of this work was the interpretation of agricultural inputs from two different agricultural catchments of the Orge River. The results showed the impact of urban uses of glyphosate upon the Orge River contamination with annual loads from 100 times higher from the urban zone than from the agricultural one. Storm sewers were recognized to be the main way for glyphosate transfer towards surface waters. A budget of glyphosate and AMPA inputs and

  4. A three-layer model of self-assembly induced surface-energy variation experimentally extracted by using nanomechanically sensitive cantilevers

    International Nuclear Information System (INIS)

    Zuo Guomin; Li Xinxin

    2011-01-01

    This research is aimed at elucidating surface-energy (or interfacial energy) variation during the process of molecule-layer self-assembly on a solid surface. A quasi-quantitative plotting model is proposed and established to distinguish the surface-energy variation contributed by the three characteristic layers of a thiol-on-gold self-assembled monolayer (SAM), namely the assembly-medium correlative gold/head-group layer, the chain/chain interaction layer and the tail/medium layer, respectively. The data for building the model are experimentally extracted from a set of correlative thiol self-assemblies in different media. The variation in surface-energy during self-assembly is obtained by in situ recording of the self-assembly induced nanomechanical surface-stress using integrated micro-cantilever sensors. Based on the correlative self-assembly experiment, and by using the nanomechanically sensitive self-sensing cantilevers to monitor the self-assembly induced surface-stressin situ, the experimentally extracted separate contributions of the three layers to the overall surface-energy change aid a comprehensive understanding of the self-assembly mechanism. Moreover, the quasi-quantitative modeling method is helpful for optimal design, molecule synthesis and performance evaluation of molecule self-assembly for application-specific surface functionalization.

  5. [A field study on the work load and muscle fatigue at neck-shoulder in female sewing machine operators by using surface electromyography].

    Science.gov (United States)

    Zhang, Fei-ruo; Wang, Sheng; He, Li-hua; Zhang, Ying; Wu, Shan-shan; Li, Jing-yun; Hu, Guang-yi; Ye, Kang-ping

    2011-03-01

    To study neck and shoulder work-related muscle fatigue of female sewing machine operators. 18 health female sewing machine operators without musculoskeletal disorders work in Beijing garment industry factory as volunteers in participate of this study. The maximal voluntary contraction (MVC) and 20% MVC of bilateral upper trapezium and cervical erectors spinae was tested before sewing operations, then the whole 20 time windows (1 time window = 10 min) sewing machine operations was monitored and the surface electromyography (sEMG) signals simultaneously was recorded after monitoring the 20%MVC was tested. Use amplitude analysis method to reduction recorded EMG signals. During work, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezium (LUT) and right upper trapezium (RUT) respectively was 6.78 ± 1.05, 6.94 ± 1.12, 5.68 ± 2.56 and 6.47 ± 3.22, work load of right is higher than the left; static load analysis indicated the value of RMS(20%MVC) before work was higher than that value after work, the increase of right CES and UT RMS(20%MVC) was more; the largest 20%MVE of bilateral CES occurred at 20th time window, and that of bilateral UT happened at 16th. The work load of female sewing machine operators is sustained "static" load, and work load of right neck-shoulder is higher than left, right neck-shoulder muscle is more fatigable and much serious once fatigued.

  6. INFLUENCE OF POSTURE ON THE RELATION BETWEEN SURFACE ELECTROMYOGRAM AMPLITUDE AND BACK MUSCLE MOMENT - CONSEQUENCES FOR THE USE OF SURFACE ELECTROMYOGRAM TO MEASURE BACK LOAD

    NARCIS (Netherlands)

    MOUTON, LJ; HOF, AL; DEJONGH, HJ; EISMA, WH

    1991-01-01

    The aim of the study was to analyse the effect of posture on the relation between EMG amplitude and moment of the back muscles in different subjects, in order to gain a better insight into the possibilities of EMG as a means of measuring individual back load. Eight healthy subjects participated in

  7. Variation and Trends of Landscape Dynamics, Land Surface Phenology and Net Primary Production of the Appalachian Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yeqiao; Zhao, Jianjun; Zhou, Yuyu; Zhang, Hongyan

    2012-12-15

    The gradients of the Appalachian Mountains in elevations and latitudes provide a unique regional perspective of landscape variations in the eastern United States and a section of the southeastern Canada. This study reveals patterns and trends of landscape dynamics, land surface phenology and ecosystem production along the Appalachian Mountains using time series data from Global Inventory Modeling and Mapping Studies (GIMMS) and AVHRR Global Production Efficiency Model (GloPEM) datasets. We analyzed the spatial and temporal patterns of Normalized Difference Vegetation Index (NDVI), length of growing season (LOS) and net primary production (NPP) of selected ecoregions along the Appalachian Mountains regions. We compared the results out of the Appalachian Mountains regions in different spatial contexts including the North America and the Appalachian Trail corridor area. To reveal latitudinal variations we analyzed data and compared the results between 30°N-40°N and 40°N-50°N latitudes. The result revealed significant decreases in annual peak NDVI in the Appalachian Mountains regions. The trend for the Appalachian Mountains regions was -0.0018 (R2=0.55, P<0.0001) NDVI unit decrease per year during 25 years between 1982 and 2006. The LOS had prolonged 0.3 day yr-1 during 25 years over the Appalachian Mountains regions. The NPP increased by 2.68 gC m-2yr-2 in Appalachian Mountains regions from 1981 to 2000. The comparison with the North America reveals the effects of topography and ecosystem compositions of the Appalachian Mountains. The comparison with the Appalachian Trail corridor area provides a regional mega-transect view of the measured variables.

  8. Mutations Affecting Keratin 10 Surface-Exposed Residues Highlight the Structural Basis of Phenotypic Variation in Epidermolytic Ichthyosis.

    Science.gov (United States)

    Mirza, Haris; Kumar, Anil; Craiglow, Brittany G; Zhou, Jing; Saraceni, Corey; Torbeck, Richard; Ragsdale, Bruce; Rehder, Paul; Ranki, Annamari; Choate, Keith A

    2015-12-01

    Epidermolytic ichthyosis (EI) due to KRT10 mutations is a rare, typically autosomal dominant, disorder characterized by generalized erythema and cutaneous blistering at birth followed by hyperkeratosis and less frequent blistering later in life. We identified two KRT10 mutations p.Q434del and p.R441P in subjects presenting with a mild EI phenotype. Both occur within the mutational "hot spot" of the keratin 10 (K10) 2B rod domain, adjacent to severe EI-associated mutations. p.Q434del and p.R441P formed collapsed K10 fibers rather than aggregates characteristic of severe EI KRT10 mutations such as p.R156C. Upon differentiation, keratinocytes from p.Q434del showed significantly lower apoptosis (P-value<0.01) compared with p.R156C as assessed by the TUNEL assay. Conversely, the mitotic index of the p.Q434del epidermis was significantly higher compared with that of p.R156C (P-value<0.01) as estimated by the Ki67 assay. Structural basis of EI phenotype variation was investigated by homology-based modeling of wild-type and mutant K1-K10 dimers. Both mild EI mutations were found to affect the surface-exposed residues of the K10 alpha helix coiled-coil and caused localized disorganization of the K1-K10 heterodimer. In contrast, adjacent severe EI mutations disrupt key intermolecular dimer interactions. Our findings provide structural insights into phenotypic variation in EI due to KRT10 mutations.

  9. Spatial-temporal variations of phosphorus fractions in surface water and suspended particles in the Daliao River Estuary, Northeast China.

    Science.gov (United States)

    Zhang, Lei; Qin, Yanwen; Han, Chaonan; Cao, Wei; Ma, Yingqun; Shi, Yao; Liu, Zhichao; Yang, Chenchen

    2016-08-01

    The transport and storage of phosphorus in estuary is a complex biogeochemical process as the result of the convergence of fresh and saline water. The objective of the current study is to investigate the spatial-temporal variations of phosphorus fractions in surface water and suspended particles of Daliao River Estuary, China. Samples were collected in August (wet season) and November (dry season), 2013. The results showed that total particulate phosphorus (TPP) in water accounted for more than 50 % of the total phosphorus (TP). Meanwhile, in suspended particles, more than 62 % of particulate phosphorus was in the form of bioavailable phosphorus, including exchangeable phosphorus (Exc-P), extractable organic phosphorus (Exo-P), and iron-bound phosphorus (Fe-P), which meant that the potential impacts of bioavailable phosphorus in suspended particles on estuarine water environment cannot be ignored. There were significantly seasonal variations of phosphorus fractions in the Daliao River Estuary. The concentrations of phosphorus fractions in water in wet season were much lower than that in dry season because of the dilution effect of larger rainfall in wet season. In addition, spatial distribution characteristics of phosphorus fractions were also obvious. Due to terrigenous phosphorus input from the upstream of tidal reach and seawater dilution effect in coastal estuary, total dissolved phosphorus (TDP) concentrations in water gradually decreased from tidal reach to coastal estuary. However, the concentrations of TPP and TP in water and Exo-P in suspended particles presented spatial fluctuation, and these were greatly attributed to sediment re-suspension in coastal estuary.

  10. Pressure sources versus surface loads : Analyzing volcano deformation signal composition with an application to Hekla volcano, Iceland

    NARCIS (Netherlands)

    Grapenthin, R.; Ófeigsson, B.G.; Sigmundsson, F.; Sturkell, E.; Hooper, A.J.

    2010-01-01

    The load of lava emplaced over periods of decades to centuries induces a gradual viscous response of the Earth resulting in measurable deformation. This effect should be considered in source model inversions for volcanic areas with large lava production and flow emplacement in small centralized

  11. The influence of pendant carboxylic acid loading on surfaces of statistical poly(4-hydroxystyrene)-co-styrene)s

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hvilsted, Søren

    2008-01-01

    . In particular, aliphatic and aromatic pendant groups differ by 92°C in Tg• Contact angle measurements onspin coated films have shown a maximum effect of the functional groups in the advancing contact angle at a 75/100 copolymer loading. In addition to this, X-ray photoelectron spectroscopy shows the presence...

  12. Influence of wind conditions on wind turbine loads and measurement of turbulence using lidars

    NARCIS (Netherlands)

    Sathe, A.R.

    2012-01-01

    Variations in wind conditions influence the loads on wind turbines significantly. In order to determine these loads it is important that the external conditions are well understood. Wind lidars are well developed nowadays to measure wind profiles upwards from the surface. But how turbulence can be

  13. Metal Ni-loaded g-C3N4 for enhanced photocatalytic H2 evolution activity: the change in surface band bending.

    Science.gov (United States)

    Bi, Lingling; Xu, Dandan; Zhang, Lijing; Lin, Yanhong; Wang, Dejun; Xie, Tengfeng

    2015-11-28

    A series of Ni@g-C3N4 composites were synthesized by a simple solvent thermal method using melamine and acetylacetone nickel as precursors. The results of X-ray diffraction, transmission electron microscopy and high resolution transmission electron microscopy indicate that Ni was successfully loaded on g-C3N4. And the Ni loaded greatly enhances the photocatalytic H2 evolution activity of g-C3N4 compared to the pure g-C3N4. In order to study the role of Ni, the surface photovoltage, the surface photocurrent and photoluminescence measurements were used to investigate the photogenerated charge properties of g-C3N4. What is more, Mott-Schottky plots and work function measurements confirmed the surface band bending change of g-C3N4 contacting with Ni. Those results demonstrate that Ni coating deepens surface band bending of g-C3N4, resulting in higher separation efficiency of photogenerated charge carriers, which is contributed to the enhanced photocatalytic H2 evolution activity.

  14. MICROBIAL LOAD AND MULTIPLE DRUG RESISTANCE OF PATHOGENIC BACTERIA ISOLATED FROM FEACES AND BODY SURFACES OF COCKROACHES IN AN URBAN AREA OF SOUTHWESTERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Monsuru Adebayo Adeleke

    2012-06-01

    Full Text Available This study investigates the microbial load and antibiotic susceptibility pattern of pathogenic bacteria isolated from the faeces and body surfaces of cockroaches in Osogbo, Southwestern Nigeria. The cockroaches collected from residential areas and hospital vicinities were screened for microbial load and antibiotic susceptibility pattern using standard protocols. A total of twenty- three microorganisms namely Klebsiella aerogenes, Bacillius cereus, Proteus spp, Staphyloccocus aureus, S. saprophyticus, Enteroccocus faecalis, Staphylococus epididermis, E. coli, Listeria monoctogene, Proteus mirabilis, Citrobacter species, Pseudomonas aeruginosa, Psuedomonas species, Seretia mensence, Candida albicans, Candida spp., Aspergilius spp., A. flavus, A. fumigates, Mucor species and Penicilium species were isolated. The microbial load of the microorganisms was significantly higher in the isolates from hospital as compared with the residential area (p<0.05 with the exception of Canidida species, Mucor and Penicillium which had higher or equal microbial load at the residential areas. All the pathogenic bacteria isolated had multiple resistance to antibiotics most importantly, Ampicillin, Augumentin, Amoxicillin and Septrin (30μg. Efforts geared towards controlling the insects will be indispensable in curbing the wide spread of multi-drug resistant pathogens in the study area.

  15. Loading of titanium implants with hydrophilic endosteal surface 3 weeks after insertion: clinical and radiological outcome of a 12-month prospective clinical trial.

    Science.gov (United States)

    Hinkle, Robert M; Rimer, Stephen R; Morgan, Michael H; Zeman, Paul

    2014-08-01

    The aim of this study was to test whether early loading (21 days after insertion) of implants with a hydrophilic surface is safe and reliable in a general clinical practice setting. This was a prospective multicenter clinical trial conducted in 3 independent surgical practices. Patients were selected according to predefined inclusion and exclusion criteria. Implants were placed in posterior regions into healed alveoli and native bone using a 1-stage (unsubmerged) surgical protocol. Loading was to be performed 21 days thereafter. Patients were followed clinically and radiographically for 1 year. Twenty-one patients who received 23 implants were followed for 1 year. None of the osseointegrated implants were lost. One broken provisional crown was reported during the trial period. The crestal bone remained remarkably stable (ie, approximately 1 mm below the microgap). The most coronal bone-to-implant contact stabilized at the level of the first implant thread just beneath the machined collar. Within the limitations of this clinical study, the authors confirmed that loading of implants with a hydrophilic surface 3 weeks after placement appears to be a safe and predictable treatment option. No crestal bone loss was observed 1 year after implant placement. Therefore, it appears that crestal bone loss is dependent on the design features of the specific implant line. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  16. Finite size effects of ionic species sensitively determine load bearing capacities of lubricated systems under combined influence of electrokinetics and surface compliance.

    Science.gov (United States)

    Naik, Kaustubh Girish; Chakraborty, Suman; Chakraborty, Jeevanjyoti

    2017-09-27

    The behaviour and health of lubricated systems in various natural and artificial settings are often characterized by their load bearing capacity. This capacity stemming from the lift force associated with confined fluid flow can be significantly altered due to surface compliance and electrokinetic effects. Here, we highlight the influence of finite size of the ionic species participating in electrokinetic transport with substrate compliance in determining the electromechanical characteristics of lubricated systems. With these new considerations, anomalous trends previously observed for the load bearing capacity corresponding to high values of zeta potential are corrected. Simultaneously, trends associated with the finite ionic size are also found to be reversed, but fall in line with the consistent theory. Importantly, despite an intricate interplay among the various influences - electrokinetic, hydrodynamic, geometric, and elastic - previously established trends due to geometric (non-parallel slider geometry) and elastic effects are found to persist. Specifically, in the presence of electrokinetic effects, an increase in the obliqueness of the slider geometry results in lower values of load bearing capacity while an increase in the stiffness leads to higher values. These results point to a certain robustness in the overall theory and it is hoped that they can contribute to better practical designs of slider bearings and an improved understanding of lubricated sliding surfaces in biological settings.

  17. Groundwater and surface-water interaction, water quality, and processes affecting loads of dissolved solids, selenium, and uranium in Fountain Creek near Pueblo, Colorado, 2012–2014

    Science.gov (United States)

    Arnold, L. Rick; Ortiz, Roderick F.; Brown, Christopher R.; Watts, Kenneth R.

    2016-11-28

    In 2012, the U.S. Geological Survey, in cooperation with the Arkansas River Basin Regional Resource Planning Group, initiated a study of groundwater and surface-water interaction, water quality, and loading of dissolved solids, selenium, and uranium to Fountain Creek near Pueblo, Colorado, to improve understanding of sources and processes affecting loading of these constituents to streams in the Arkansas River Basin. Fourteen monitoring wells were installed in a series of three transects across Fountain Creek near Pueblo, and temporary streamgages were established at each transect to facilitate data collection for the study. Groundwater and surface-water interaction was characterized by using hydrogeologic mapping, groundwater and stream-surface levels, groundwater and stream temperatures, vertical hydraulic-head gradients and ratios of oxygen and hydrogen isotopes in the hyporheic zone, and streamflow mass-balance measurements. Water quality was characterized by collecting periodic samples from groundwater, surface water, and the hyporheic zone for analysis of dissolved solids, selenium, uranium, and other selected constituents and by evaluating the oxidation-reduction condition for each groundwater sample under different hydrologic conditions throughout the study period. Groundwater loads to Fountain Creek and in-stream loads were computed for the study area, and processes affecting loads of dissolved solids, selenium, and uranium were evaluated on the basis of geology, geochemical conditions, land and water use, and evapoconcentration.During the study period, the groundwater-flow system generally contributed flow to Fountain Creek and its hyporheic zone (as a single system) except for the reach between the north and middle transects. However, the direction of flow between the stream, the hyporheic zone, and the near-stream aquifer was variable in response to streamflow and stage. During periods of low streamflow, Fountain Creek generally gained flow from

  18. Application of advanced biomechanical methods in studying low back pain – recent development in estimation of lower back loads and large-array