Film Boiling on Downward Quenching Hemisphere of Varying Sizes

Energy Technology Data Exchange (ETDEWEB)

Chan S. Kim; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

2004-04-01

Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Laminar Transition Apparatus). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of all the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the interfacial wavy motion and the quenching process are visualized through a digital camera.

Coarse-graining as a downward causation mechanism

Science.gov (United States)

Flack, Jessica C.

2017-11-01

Downward causation is the controversial idea that `higher' levels of organization can causally influence behaviour at `lower' levels of organization. Here I propose that we can gain traction on downward causation by being operational and examining how adaptive systems identify regularities in evolutionary or learning time and use these regularities to guide behaviour. I suggest that in many adaptive systems components collectively compute their macroscopic worlds through coarse-graining. I further suggest we move from simple feedback to downward causation when components tune behaviour in response to estimates of collectively computed macroscopic properties. I introduce a weak and strong notion of downward causation and discuss the role the strong form plays in the origins of new organizational levels. I illustrate these points with examples from the study of biological and social systems and deep neural networks. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Effect of subcooling and wall thickness on pool boiling from downward-facing curved surfaces in water

Energy Technology Data Exchange (ETDEWEB)

El-Genk, M.S.; Glebov, A.G. [Univ. of New Mexico, Albuquerque, NM (United States)

1995-09-01

Quenching experiments were performed to investigate the effects of water subcooling and wall thickness on pool boiling from a downward-facing curved surface. Experiments used three copper sections of the same diameter (50.8 mm) and surface radius (148 mm), but different thickness (12.8, 20 and 30 mm). Local and average pool boiling curves were obtained at saturation and 5 K, 10 K, and 14 K subcooling. Water subcooling increased the maximum heat flux, but decreased the corresponding wall superheat. The minimum film boiling heat flux and the corresponding wall superheat, however, increased with increased subcooling. The maximum and minimum film boiling heat fluxes were independent of wall thickness above 20 mm and Biot Number > 0.8, indicating that boiling curves for the 20 and 30 thick sections were representative of quasi steady-state, but not those for the 12.8 mm thick section. When compared with that for a flat surface section of the same thickness, the data for the 12.8 mm thick section showed significant increases in both the maximum heat flux (from 0.21 to 0.41 MW/m{sup 2}) and the minimum film boiling heat flux (from 2 to 13 kW/m{sup 2}) and about 11.5 K and 60 K increase in the corresponding wall superheats, respectively.

Numerical analysis of transient heat conduction in downward-facing curved sections during quenching

International Nuclear Information System (INIS)

Gao, C.; El-Genk, M.S.

1996-01-01

Pool boiling from downward-facing surfaces is of interest in many applications such as cooling of electric cables, handling of containers of hazardous liquids and external cooling of nuclear reactor vessels. Here, a two-dimensional numerical analysis was performed to determine pool boiling curves from downward-facing curved stainless-steel and copper surfaces during quenching in saturated water. To ensure stability and accuracy of the numerical solution, the alternating direction implicit (ADI) method based on finite control volume representations was employed. A time dependent boundary condition was provided by the measured temperature at nine interior locations near the boiling surface. Best results were obtained using a grid of 20x20 CVs and a non-iterative approach. Calculated temperatures near the top surface of the metal sections agreed with measured values to within 0.5 K and 2.5 K for the copper and stainless-steel sections, respectively. The running time on a Pentium 90 MHz PC for the entire boiling curve was 7% of the real transient time and 4% of that of a simplified Gaussian elimination (SGE) method for the Crank-Nicolson scheme

Studies on boiling heat transfer on a hemispherical downward heating surface supposing IVR-AM

International Nuclear Information System (INIS)

Yoshida, Kenji; Matsumoto, Hiroyuki; Matsumoto, Tadayoshi; Kataoka, Isao

2006-01-01

The scale-down experiments supposing the IVR-AM were made on the pool boiling heat transfer from hemispherical downward facing heating surface. The boiling phenomena were realized by flooding the heated hemispherical vessel into the sub-cooled water or saturated water under the atmospheric pressure. The hemispherical vessel supposing the scale-down pressure vessel was made of SUS304 stainless steel. Molten lead, which was preheated up to about 500 degrees Celsius, was put into the vessel and used as the heat source. The vessel was cooled down by flooding into the water to realize the quenching process. The direct observation by using the digital video camera was performed and made clear the special characteristics of boiling phenomena such as the film boiling, the transition boiling and the nucleate boiling taking place in order during the cooling process. The measurement for the wall superheat and heat flux by using thermocouples was also carried out to make clear the boiling heat transfer characteristics during the cooling process. Fifteen thermocouples are inserted in the wall of the hemispherical bowl to measure the temperature distributions and heat flux in the hemispherical bowl. (author)

Experimental study for flow regime of downward air-water two-phase flow in a vertical narrow rectangular channel

Energy Technology Data Exchange (ETDEWEB)

Kim, T. H.; Yun, B. J.; Jeong, J. H. [Pusan National University, Geunjeong-gu, Busan (Korea, Republic of)

2015-05-15

Studies were mostly about flow in upward flow in medium size circular tube. Although there are great differences between upward and downward flow, studies on vertical upward flow are much more active than those on vertical downward flow in a channel. In addition, due to the increase of surface forces and friction pressure drop, the pattern of gas-liquid two-phase flow bounded to the gap of inside the rectangular channel is different from that in a tube. The downward flow in a rectangular channel is universally applicable to cool the plate type nuclear fuel in research reactor. The sub-channel of the plate type nuclear fuel is designed with a few millimeters. Downward air-water two-phase flow in vertical rectangular channel was experimentally observed. The depth, width, and length of the rectangular channel is 2.35 mm, 66.7 mm, and 780 mm, respectively. The test section consists of transparent acrylic plates confined within a stainless steel frame. The flow patterns of the downward flow in high liquid velocity appeared to be similar to those observed in previous studies with upward flow. In downward flow, the transition lines for bubbly-slug and slug-churn flow shift to left in the flow regime map constructed with abscissa of the superficial gas velocity and ordinate of the superficial liquid velocity. The flow patterns observed with downward flow at low liquid velocity are different from those with upward flow.

Uncertainty Estimate of Surface Irradiances Computed with MODIS-, CALIPSO-, and CloudSat-Derived Cloud and Aerosol Properties

Science.gov (United States)

Kato, Seiji; Loeb, Norman G.; Rutan, David A.; Rose, Fred G.; Sun-Mack, Sunny; Miller, Walter F.; Chen, Yan

2012-07-01

Differences of modeled surface upward and downward longwave and shortwave irradiances are calculated using modeled irradiance computed with active sensor-derived and passive sensor-derived cloud and aerosol properties. The irradiance differences are calculated for various temporal and spatial scales, monthly gridded, monthly zonal, monthly global, and annual global. Using the irradiance differences, the uncertainty of surface irradiances is estimated. The uncertainty (1σ) of the annual global surface downward longwave and shortwave is, respectively, 7 W m-2 (out of 345 W m-2) and 4 W m-2 (out of 192 W m-2), after known bias errors are removed. Similarly, the uncertainty of the annual global surface upward longwave and shortwave is, respectively, 3 W m-2 (out of 398 W m-2) and 3 W m-2 (out of 23 W m-2). The uncertainty is for modeled irradiances computed using cloud properties derived from imagers on a sun-synchronous orbit that covers the globe every day (e.g., moderate-resolution imaging spectrometer) or modeled irradiances computed for nadir view only active sensors on a sun-synchronous orbit such as Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation and CloudSat. If we assume that longwave and shortwave uncertainties are independent of each other, but up- and downward components are correlated with each other, the uncertainty in global annual mean net surface irradiance is 12 W m-2. One-sigma uncertainty bounds of the satellite-based net surface irradiance are 106 W m-2 and 130 W m-2.

Practices and attitudes of doctors and patients to downward referral in Shanghai, China.

Science.gov (United States)

Yu, Wenya; Li, Meina; Nong, Xin; Ding, Tao; Ye, Feng; Liu, Jiazhen; Dai, Zhixing; Zhang, Lulu

2017-04-03

In China, the rate of downward referral is relatively low, as most people are unwilling to be referred from hospitals to community health systems (CHSs). The aim of this study was to explore the effect of doctors' and patients' practices and attitudes on their willingness for downward referral and the relationship between downward referral and sociodemographic characteristics. Doctors and patients of 13 tertiary hospitals in Shanghai were stratified through random sampling. The questionnaire surveyed their sociodemographic characteristics, attitudes towards CHSs and hospitals, understanding of downward referral, recognition of the community first treatment system, and downward referral practices and willingness. Descriptive statistics, χ 2 test and stepwise logistic regression analysis were employed for statistical analysis. Only 20.8% (161/773) of doctors were willing to accept downward referrals, although this proportion was higher among patients (37.6%, 326/866). Doctors' willingness was influenced by education, understanding of downward referral, and perception of health resources in hospitals. Patients' willingness was influenced by marital status, economic factors and recognition of the community first treatment system. Well-educated doctors who do not consider downward referral would increase their workloads and those with a more comprehensive understanding of hospitals and downward referral process were more likely to make a downward referral decision. Single-injury patients fully recognising the community first treatment system were more willing to accept downward referral. Patients' willingness was significantly increased if downward referral was cost-saving. A better medical insurance system was another key factor for patients to accept downward referral decisions, especially for the floating population. To increase the rate of downward referral, the Chinese government should optimise the current referral system and conduct universal publicity for

Downward surface flux computations in a vertically inhomogeneous grey planetary atmosphere Cálculo do fluxo radiativo superficial em uma atmosfera planetária cinza e verticalmente não-homogênea

Directory of Open Access Journals (Sweden)

Marcos Pimenta de Abreu

2008-03-01

Full Text Available We describe an efficient computational scheme for downward surface flux computations in a vertically inhomogeneous grey planetary atmosphere for different values of solar zenith angle. We start with the basic equations of a recently developed discrete ordinates spectral nodal method, and we derive suitable bidirectional functions whose diffuse components do not depend on the solar zenith angle. We then make use of these bidirectional functions to construct an efficient scheme for computing the downward surface fluxes in a given model atmosphere for a number of solar zenith angles. We illustrate the merit of the computational scheme described here with downward surface flux computations in a three-layer grey model atmosphere for four values of solar zenith angle, and we conclude this article with general remarks and directions for future work.Este artigo descreve um esquema computacional baseado em desenvolvimentos recentes do método espectro-nodal de ordenadas discretas para o cálculo eficiente do fluxo radiativo superficial em uma atmosfera planetária cinza e verticalmente não-homogênea para valores distintos do ângulo zenital solar. A partir das equações básicas do método espectro-nodal de ordenadas discretas, são obtidas funções bidirecionais discretas cujas componentes difusas não dependem do ângulo zenital solar. Com essas funções bidirecionais discretas, é construído um esquema computacional para calcular eficientemente fluxos radiativos superficiais em uma dada atmosfera-modelo para vários ângulos zenitais solares. O mérito computacional do esquema resultante é ilustrado com resultados numéricos para os fluxos radiativos superficiais em uma atmosfera-modelo cinza com três camadas para quatro valores distintos do ângulo zenital solar. Este artigo é finalizado com observações gerais e indicações de trabalhos futuros.

SIMULATION OF ANALYTICAL TRANSIENT WAVE DUE TO DOWNWARD BOTTOM THRUST

Directory of Open Access Journals (Sweden)

Sugih Sudharma Tjandra

2015-11-01

Full Text Available Generation process is an important part of understanding waves, especially tsunami. Large earthquake under the sea is one major cause of tsunamis. The sea surface deforms as a response from the sea bottom motion caused by the earthquake. Analytical description of surface wave generated by bottom motion can be obtained from the linearized dispersive model. For a bottom motion in the form of a downward motion, the result is expressed in terms of improper integral. Here, we focus on analyzing the convergence of this integral, and then the improper integral is approximated into a finite integral so that the integral can be evaluated numerically. Further, we simulate free surface elevation for three different type of bottom motions, classified as impulsive, intermediate, and slow  movements. We demonstrate that the wave propagating to the right, with a depression as the leading wave, followed with subsequent wave crests. This phenomena is often observed in most tsunami events.

Variability and trends of downward surface global solar radiation over the Iberian Peninsula based on ERA-40 reanalysis

KAUST Repository

Perdigão, João Carlos

2016-01-26

© 2016 Royal Meteorological Society. A climate study of the incidence of downward surface global solar radiation (SSRD) in the Iberian Peninsula (IP) based primarily on ERA-40 reanalysis is presented. NCEP/NCAR reanalysis and ground-based records from several Portuguese and Spanish stations have been also considered. The results show that reanalysis can capture a similar inter-annual variability as compared to ground-based observations, especially on a monthly basis, even though annual ERA-40 (NCEP/NCAR) values tend to underestimate (overestimate) the observations with a mean relative difference of around 20Wm-2 (40Wm-2). On the other hand, ground-based measurements in Portuguese stations during the period 1964-1989 show a tendency to decrease until the mid-1970s followed by an increase up to the end of the study period, in line with the dimming/brightening phenomenon reported in the literature. Nevertheless, there are different temporal behaviours as a greater increase since the 1970s is observed in the south and less industrialized regions. Similarly, the ERA-40 reanalysis shows a noticeable decrease until the early 1970s followed by a slight increase up to the end of the 1990s, suggesting a dimming/brightening transition around the early 1970s, earlier in the south and centre and later in the north of the IP. Although there are slight differences in the magnitude of the trends as well as the turning year of the dimming/brightening periods, the decadal changes of ERA-40 fairly agree with the ground-based observations in Portugal and Spain, in contrast to most of the literature for other regions of the world, and is used in the climatology of the SSRD in the study area. NCEP/NCAR reanalysis does not capture the decadal variations of SSRD in the IP. The results show that part of the decadal variability of the global radiation in the IP is related to changes in cloud cover (represented in ERA-40).

Variability and trends of downward surface global solar radiation over the Iberian Peninsula based on ERA-40 reanalysis

KAUST Repository

Perdigã o, Joã o Carlos; Salgado, Rui; Costa, Maria Joã o; Dasari, Hari Prasad; Sanchez-Lorenzo, Arturo

2016-01-01

© 2016 Royal Meteorological Society. A climate study of the incidence of downward surface global solar radiation (SSRD) in the Iberian Peninsula (IP) based primarily on ERA-40 reanalysis is presented. NCEP/NCAR reanalysis and ground-based records from several Portuguese and Spanish stations have been also considered. The results show that reanalysis can capture a similar inter-annual variability as compared to ground-based observations, especially on a monthly basis, even though annual ERA-40 (NCEP/NCAR) values tend to underestimate (overestimate) the observations with a mean relative difference of around 20Wm-2 (40Wm-2). On the other hand, ground-based measurements in Portuguese stations during the period 1964-1989 show a tendency to decrease until the mid-1970s followed by an increase up to the end of the study period, in line with the dimming/brightening phenomenon reported in the literature. Nevertheless, there are different temporal behaviours as a greater increase since the 1970s is observed in the south and less industrialized regions. Similarly, the ERA-40 reanalysis shows a noticeable decrease until the early 1970s followed by a slight increase up to the end of the 1990s, suggesting a dimming/brightening transition around the early 1970s, earlier in the south and centre and later in the north of the IP. Although there are slight differences in the magnitude of the trends as well as the turning year of the dimming/brightening periods, the decadal changes of ERA-40 fairly agree with the ground-based observations in Portugal and Spain, in contrast to most of the literature for other regions of the world, and is used in the climatology of the SSRD in the study area. NCEP/NCAR reanalysis does not capture the decadal variations of SSRD in the IP. The results show that part of the decadal variability of the global radiation in the IP is related to changes in cloud cover (represented in ERA-40).

Design of Hemispherical Downward-Facing Vessel for Critical Heat Flux Experiment

International Nuclear Information System (INIS)

Hwang, J. S.; Suh, K. Y.

2009-01-01

The in-vessel retention (IVR) is one of major severe accident management strategies adopted by some operating nuclear power plants during a severe accident. The recent Shin-Gori Units 3 and 4 of the Advanced Power Reactor 1400 MWe (APR1400) have adopted the external reactor vessel cooling (ERVC) by reactor cavity flooding as major severe accident management strategy. The ERVC in the APR1400 design resorts to active flooding system using thermal insulator. The Corium Attack Stopper Apparatus Spherical Channel (CASA SC) tests are conducted to measure the critical power and critical heat flux (CHF) on a downward hemispherical vessel scaled down from the APR1400 lower head by 1/10 on a linear scale. CASA is designed through scaling and thermal analysis to simulate the APR1400 vessel and thermal insulator. The heated vessel of CASA SC represents the external surface of a hemisphere submerged vessel in water. The heated vessel plays an important role in the ERVC experiment depending on the configuration of oxide pool and metallic layer. Hand calculation and computational analysis are performed to produce high heat flux from the downward facing hemisphere in excess of 1 MW/m 2

Macrokinetic determination of isopropanol removal using a downward flow biofilter

Directory of Open Access Journals (Sweden)

Vissanu Meeyoo

2004-02-01

Full Text Available Biofiltration is a process for eliminating contaminants in air using microorganisms immobilized on a surface of solid support media. This technique has been used successfully to control a number of air contaminants such as odors, Volatile Organic Compounds (VOCs, and Hazardous Air Pollutants (HAPs due to its economic attraction.Microorganisms obtained from local activated sludge (Huay-Kwang wastewater treatment plant (Bangkok, Thailand were selectively enriched and inoculated to the biofilter. The downward flow biofilterwas chosen, due to the ease of water compensation at the dry zone, to operate continuously for more than 3 months under various concentrations of isopropanol alcohol (IPA input at a constant filtered air flow rate of 3 L/min. The maximum IPA elimination capacity of 276 g/m3-h was achieved at the IPA inlet of 342 g/m3-h with acetone production rate of 56 g/m3-h as the intermediate. It was also found that the acetone vapour was partly degraded by the acetone-utilizing microorganisms before leaving the bed. In order to understand the transport phenomena of biofiltration, it is necessary to consider the kinetic behavior of the bioreaction. Therefore, this paper introduces Wani’s method of macrokinetic determination based on the simple Monod kinetic (Wani, Lau and Branion, 1999. In this study, the maximum reaction rate per unit volume (Rm and the Monod constant (KM were found to be 0.12 g/m3 -s and 2.72 g/m3 respectively.

Flexible Consumers Reserving Electricity and Offering Profitable Downward Regulation

OpenAIRE

Höning, Nicolas; La Poutré, Han; Strunz, K.

2012-01-01

htmlabstractPrevious work on demand response in smart grids considers dynamic real-time prices, but has so far neglected to consider how consumers can also be involved in planning ahead, both for scheduling of consumption and reserving their ability to regulate downward during balancing. This work models a flexible consumer in a novel two-settlement electricity auction. The consumer buys electricity on an ahead market and offers downward regulation on the balancing market. Bidding in two- set...

Single bubble dynamic behavior in AL{sub 2}O{sub 3}/H{sub 2}O nanofluid on downward-facing heating surface

Energy Technology Data Exchange (ETDEWEB)

Wang, Yun; Wu, Junmei [State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an (China)

2016-08-15

After a severe accident to the nuclear reactor, the in-vessel retention strategy is a key way to prevent the leakage of radioactive material. Nanofluid is a steady suspension used to improve heat-transfer characteristics of working fluids, formed by adding solid particles with diameters below 100 nm to the base fluids, and its thermal physical properties and heat-transfer characteristics are much different from the conventional working fluids. Thus, nanofluids with appropriate nanoparticle type and volume concentration can enhance the heat-transfer process. In this study, the moving particle semi-implicit method-meshless advection using flow-directional local grid method is used to simulate the bubble growth, departure, and sliding on the downward-facing heating surface in pure water and nanofluid (1.0 vol.% Al2O3/H2O) flow boiling processes; additionally, the bubble critical departure angle and sliding characteristics and their influence are also investigated. The results indicate that the bubble in nanofluid departs from the heating surface more easily and the critical departure inclined angle of nanofluid is greater than that of pure water. In addition, the influence of nanofluid on bubble sliding is not significant compared with pure water.

Cover Art: River's Edge: Downward, Outward, Upward

Directory of Open Access Journals (Sweden)

Jonee Kulman Brigham

2017-10-01

Full Text Available Artist's Statement for the cover art of IJPS volume 4, issue 3: River's Edge: Downward, Outward, Upward, 2015. Mixed Media: photograph, inkjet printed on presentation matte of colored pencil over photograph.

Inlet effects on vertical-downward air–water two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Qiao, Shouxu; Mena, Daniel; Kim, Seungjin, E-mail: skim@psu.edu

2017-02-15

Highlights: • Inlet effects on two-phase flow parameters in vertical-downward flow are studied. • Flow regimes in the vertical-downward two-phase flow are defined. • Vertical-downward flow regime maps for three inlet configurations are developed. • Frictional pressure loss analysis for three different inlets is performed. • Database of local two-phase flow parameters for each inlet configuration. - Abstract: This paper focuses on investigating the geometric effects of inlets on global and local two-phase flow parameters in vertical-downward air–water two-phase flow. Flow visualization, frictional pressure loss analysis, and local experiments are performed in a test facility constructed from 50.8 mm inner diameter acrylic pipes. Three types of inlets of interest are studied: (1) two-phase flow injector without a flow straightener (Type A), (2) two-phase flow injector with a flow straightener (Type B), and (3) injection through a horizontal-to-vertical-downward 90° vertical elbow (Type C). A detailed flow visualization study is performed to characterize flow regimes including bubbly, slug, churn-turbulent, and annular flow. Flow regime maps for each inlet are developed and compared to identify the effects of each inlet. Frictional pressure loss analysis shows that the Lockhart–Martinelli method is capable of correlating the frictional loss data acquired for Type B and Type C inlets with a coefficient value of C = 25, but additional data may be needed to model the Type A inlet. Local two-phase flow parameters measured by a four-sensor conductivity probe in four bubbly and near bubbly flow conditions are analyzed. It is observed that vertical-downward two-phase flow has a characteristic center-peaked void profile as opposed to a wall-peaked profile as seen in vertical-upward flow. Furthermore, it is shown that the Type A inlet results in the most pronounced center-peaked void fraction profile, due to the coring phenomenon. Type B and Type C inlets

Study of natural energy system and downward atmospheric radiation. Part 2. Study of downward atmospheric radiation simple estimated formula and elective longwave radiation; Shizen energy system to tenku hosharyo no kansoku kenkyu. 2. Tenku hosharyo kan`i suiteishiki to jikko hosharyo no kento

Energy Technology Data Exchange (ETDEWEB)

Ohashi, K; Yano, S [Kogakuin University, Tokyo (Japan); Masuoka, Y

1997-11-25

With an objective to design and control a natural energy utilization system, this paper describes discussions on a simple estimation formula for downward atmospheric radiation. The simple estimation formula for downward atmospheric radiation using a square root of steam partial pressure, {sigma}T{sup 4} ({sigma} is the Stefan Boltzmann constant, and T is the absolute outside air temperature), and SAT (observation value for corresponding outside air temperature) as explanatory variables was added with data made available further to improve its accuracy. A calculated value, whose formula had observation values at each location substituted, had coefficient of correlation with the observation values of 0.9. This formula was found applicable to each location. The effective radiation amount is the difference between the downward atmospheric radiation and the long wavelength radiation from the ground surface, from which a formula to simply estimate the effective radiation was proposed. Although there is a slight difference, the calculated values derived by using this formula agreed nearly well with the observation values of the effective radiation. A standard SAT meter was used to discuss cooling effect of atmospheric radiation cooling on the ground surface, whereas the cooling effect was verified to appear markedly under windless condition at night. It was found that the cooling effect is more remarkable in winter than in summer. 14 refs., 8 figs., 1 tab.

International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 3 Monthly

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Global Land Surface Temperature Databank contains monthly timescale mean, maximum, and minimum temperature for approximately 40,000 stations globally. It was...

International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 2 Monthly

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 1 Monthly

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

Effect of the Aligned Flow Obstacles on Downward-Facing CHF in an Inclined Rectangular Channel

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ui ju; Son, Hong Hyun; Seo, Gwang Hyeok; Jeun, Gyoo Dong; Kim, Sung Joong [Hanyang, Seoul (Korea, Republic of)

2016-05-15

The cooling channel consists of the inclined (10 .deg. ) portion of the downward facing heating channel and vertical portion of the heating channel. Features unique to flow boiling with the downward-facing heater surface in the inclined cooling channel where the studs are installed have drawn a considerable attention. That's because prior studies on boiling crisis indicate the orientation of the heated wall can exert substantial influence on CHF. Especially, the concentration of the vapor near the downward facing heater surface makes this region susceptible to premature boiling crisis when compared to vertical or upward-facing heated wall. Also, the installed studs could cause a partial flow blockage, and distort the flow streamline. Due to the distortion, stagnation points may occur in the cooling channel, promoting the concentration of the vapor near the heated wall. Then, the locally degraded heat transfer around the points may result in the formation of vapor pocket. The primary objective of this study is to make available experimental data on the CHF values varying the shape of studs and to improve understanding of the mechanism of flow boiling crisis associated with the aligned flow obstructions by means of visual experimental study. This study presents experimental data for subcooled flow boiling of water at atmospheric pressure and low mass flux conditions. The major outcomes from this investigation can be summarized as follows: (1) The CHF value from bare test section is -320kW/m{sup 2} , significantly lower than the values from the existing correlations even considering the uncertainty in the experiments. (2) The CHF value is remarkably decreased as columnar structures are installed in the channel. It is confirmed that formation and extinction of local dryout occurs repeatedly just behind the first stud at heat flux of -160 kW/m{sup 2}.

A machine learning approach to estimation of downward solar radiation from satellite-derived data products: An application over a semi-arid ecosystem in the U.S.

Science.gov (United States)

Zhou, Qingtao; Flores, Alejandro; Glenn, Nancy F; Walters, Reggie; Han, Bangshuai

2017-01-01

Shortwave solar radiation is an important component of the surface energy balance and provides the principal source of energy for terrestrial ecosystems. This paper presents a machine learning approach in the form of a random forest (RF) model for estimating daily downward solar radiation flux at the land surface over complex terrain using MODIS (MODerate Resolution Imaging Spectroradiometer) remote sensing data. The model-building technique makes use of a unique network of 16 solar flux measurements in the semi-arid Reynolds Creek Experimental Watershed and Critical Zone Observatory, in southwest Idaho, USA. Based on a composite RF model built on daily observations from all 16 sites in the watershed, the model simulation of downward solar radiation matches well with the observation data (r2 = 0.96). To evaluate model performance, RF models were built from 12 of 16 sites selected at random and validated against the observations at the remaining four sites. Overall root mean square errors (RMSE), bias, and mean absolute error (MAE) are small (range: 37.17 W/m2-81.27 W/m2, -48.31 W/m2-15.67 W/m2, and 26.56 W/m2-63.77 W/m2, respectively). When extrapolated to the entire watershed, spatiotemporal patterns of solar flux are largely consistent with expected trends in this watershed. We also explored significant predictors of downward solar flux in order to reveal important properties and processes controlling downward solar radiation. Based on the composite RF model built on all 16 sites, the three most important predictors to estimate downward solar radiation include the black sky albedo (BSA) near infrared band (0.858 μm), BSA visible band (0.3-0.7 μm), and clear day coverage. This study has important implications for improving the ability to derive downward solar radiation through a fusion of multiple remote sensing datasets and can potentially capture spatiotemporally varying trends in solar radiation that is useful for land surface hydrologic and terrestrial

Modeled Downward Transport of a Passive Tracer over Western North America during an Asian Dust Event in April 1998.

Science.gov (United States)

Hacker, Joshua P.; McKendry, Ian G.; Stull, Roland B.

2001-09-01

An intense Gobi Desert dust storm in April 1998 loaded the midtroposphere with dust that was transported across the Pacific to western North America. The Mesoscale Compressible Community (MC2) model was used to investigate mechanisms causing downward transport of the midtropospheric dust and to explain the high concentrations of particulate matter of less than 10-m diameter measured in the coastal urban areas of Washington and southern British Columbia. The MC2 was initialized with a thin, horizontally homogeneous layer of passive tracer centered at 650 hPa for a simulation from 0000 UTC 26 April to 0000 UTC 30 April 1998. Model results were in qualitative agreement with observed spatial and temporal patterns of particulate matter, indicating that it captured the important meteorological processes responsible for the horizontal and vertical transport over the last few days of the dust event. A second simulation was performed without topography to isolate the effects of topography on downward transport.Results show that the dust was advected well east of the North American coast in southwesterly midtropospheric flow, with negligible dust concentration reaching the surface initially. Vertically propagating mountain waves formed during this stage, and differences between downward and upward velocities in these waves could account for a rapid descent of dust to terrain height, where the dust was entrained into the turbulent planetary boundary layer. A deepening outflow (easterly) layer near the surface transported the tracer westward and created a zonal-shear layer that further controlled the tracer advection. Later, the shear layer lifted, leading to a downward hydraulic acceleration along the western slopes, as waves generated in the easterly flow amplified below the shear layer that was just above mountain-crest height. Examination of 10 yr of National Centers for Environmental Prediction-National Center for Atmospheric Research reanalyses suggests that such events

Air pocket removal from downward sloping pipes

NARCIS (Netherlands)

Pothof, I.W.M.; Clemens, F.H.L.R.

2012-01-01

Air-water flow is an undesired condition in water pipelines and hydropower tunnels. Water pipelines and wastewater pressure mains in particular are subject to air pocket accumulation in downward sloping reaches, such as inverted siphons or terrain slopes. Air pockets cause energy losses and an

Measurement of pool boiling CHF for SUS 304 and SA 508 flat plate under downward-facing and atmospheric conditions

International Nuclear Information System (INIS)

Kam, Dong Hoon; Park, Hae Min; Choi, Young Jae; Jeong, Yong Hoon

2015-01-01

Heat transfer performance of downward-facing conditions are important especially in severe accident mitigation strategy (IVR-ERVC and Core-catcher). Heat transfer limit, in other word, critical heat flux (CHF) is important value in this basis to guarantee the integrity of the system. For the application point of view in nuclear power plant, carbon steel surface should also be considered since reactor pressure vessel (RPV) in IVR-ERVC strategy consists of carbon steel, and core-catcher in EU-APR1400 is also composed of carbon steel. In this perspective, carbon steel surface was used in previous studies. In this study, CHF of both stainless steel and carbon steel material were measured under pool boiling condition with various inclination angles and dimensions. There was a width effect as angle increases, but it disappeared as approached to horizontally downward condition. Besides, there was almost no length effect for both of the width since the size of coalesced bubble was far smaller than the length of short test section (100 mm). SA 508 showed enhanced results at high angles for 40 mm-width case even though no oxidation occurred on the surface during the experiments

Measurement of pool boiling CHF for SUS 304 and SA 508 flat plate under downward-facing and atmospheric conditions

Energy Technology Data Exchange (ETDEWEB)

Kam, Dong Hoon; Park, Hae Min; Choi, Young Jae; Jeong, Yong Hoon [KAIST, Daejeon (Korea, Republic of)

2015-05-15

Heat transfer performance of downward-facing conditions are important especially in severe accident mitigation strategy (IVR-ERVC and Core-catcher). Heat transfer limit, in other word, critical heat flux (CHF) is important value in this basis to guarantee the integrity of the system. For the application point of view in nuclear power plant, carbon steel surface should also be considered since reactor pressure vessel (RPV) in IVR-ERVC strategy consists of carbon steel, and core-catcher in EU-APR1400 is also composed of carbon steel. In this perspective, carbon steel surface was used in previous studies. In this study, CHF of both stainless steel and carbon steel material were measured under pool boiling condition with various inclination angles and dimensions. There was a width effect as angle increases, but it disappeared as approached to horizontally downward condition. Besides, there was almost no length effect for both of the width since the size of coalesced bubble was far smaller than the length of short test section (100 mm). SA 508 showed enhanced results at high angles for 40 mm-width case even though no oxidation occurred on the surface during the experiments.

Liquid velocity in upward and downward air-water flows

International Nuclear Information System (INIS)

Sun Xiaodong; Paranjape, Sidharth; Kim, Seungjin; Ozar, Basar; Ishii, Mamoru

2004-01-01

Local characteristics of the liquid phase in upward and downward air-water two-phase flows were experimentally investigated in a 50.8-mm inner-diameter round pipe. An integral laser Doppler anemometry (LDA) system was used to measure the axial liquid velocity and its fluctuations. No effect of the flow direction on the liquid velocity radial profile was observed in single-phase liquid benchmark experiments. Local multi-sensor conductivity probes were used to measure the radial profiles of the bubble velocity and the void fraction. The measurement results in the upward and downward two-phase flows are compared and discussed. The results in the downward flow demonstrated that the presence of the bubbles tended to flatten the liquid velocity radial profile, and the maximum liquid velocity could occur off the pipe centerline, in particular at relatively low flow rates. However, the maximum liquid velocity always occurred at the pipe center in the upward flow. Also, noticeable turbulence enhancement due to the bubbles in the two-phase flows was observed in the current experimental flow conditions. Furthermore, the distribution parameter and the void-weighted area-averaged drift velocity were obtained based on the definitions

Interfacial structures in downward two-phase bubbly flow

International Nuclear Information System (INIS)

Paranjape, S.S.; Kim, S.; Ishii, M.; Kelly, J.

2003-01-01

Downward two-phase flow was studied considering its significance in view of Light Water Reactor Accidents (LWR) such as Loss of Heat Sink (LOHS) by feed water loss or secondary pipe break. The flow studied, was an adiabatic, air-water, co-current, vertically downward two-phase flow. The experimental test sections had internal hydraulic diameters of 25.4 mm and 50.8 mm. Flow regime map was obtained using the characteristic signals obtained from an impedance void meter, employing neural network based identification methodology to minimize the subjective judgment in determining the flow regimes. A four sensor conductivity probe was used to measure the local two phase flow parameters, which characterize the interfacial structures. The local time averaged two-phase flow parameters measured were: void fraction (α), interfacial area concentration (a i ), bubble velocity (v g ), and Sauter mean diameter (D Sm ). The flow conditions were from the bubbly flow regime. The local profiles of these parameters as well as their axial development revealed the nature of the interfacial structures and the bubble interaction mechanisms occurring in the flow. Furthermore, this study provided a good database for the development of the interfacial area transport equation, which dynamically models the changes in the interfacial area along the flow field. An interfacial area transport equation was developed for downward flow based on that developed for the upward flow, with certain modifications in the bubble interaction terms. The area averaged values of the interfacial area concentration were compared with those predicted by the interfacial area transport model. (author)

Experimental study on downward two-phase flow in narrow rectangular channel

Energy Technology Data Exchange (ETDEWEB)

Kim, T.H.; Jeong, J.H. [Pusan National Univ., Busan (Korea, Republic of)

2014-07-01

Adiabatic vertical two-phase flow of air and water through narrow rectangular channels was investigated. This study involved the observation of flow using a high speed camera and flow regimes were determined by image processing program using a MATLAB. The flows regimes in channel with downward flow are similar to those found by previous studies with upward flow. The flow regimes in downward flow at low liquid velocity are different from the previous studies in upward flow. The flow regimes can be classified into bubbly, cap-bubbly, slug and churn flow. (author)

Analysis of steady state and transient two-phase flows in downwardly inclined lines

International Nuclear Information System (INIS)

Crawford, T.J.

1983-01-01

A study of steady-state and transient two-phase flows in downwardly inclined lines is described. Steady-state flow patterns maps are presented using Freon-113 as the working fluid to provide new high density vapors. These flow maps with high density vapor serve to significantly extend the investigations of steady-state downward two-phase flow patterns. Physical models developed which successfully predicted the onset or location of various flow pattern transitions. A new simplified criterion that would be useful to designers and experimenters is offered for the onset of dispersed flow. A new empirical holdup correlation and a new bubble diameter/flow rate correlation are also proposed. Flow transients in vertical downward lines were studied to investigate the possible formation of intermediate or spurious flow patterns that would not be seen at steady-state conditions. Void fraction behavior during the transients was modeled by using the dynamic slip equation from the transient analysis code RETRAN. Physical models of interfacial area were developed and compared with models and data from literature. There was satisfactory agreement between the models of the present study and the literature models and data. The concentration parameter of the drift flux model was evaluated for vertical downward flow. These new values of the flow dependent parameter were different from those previously proposed in the literature for use in upward flows, and made the drift flux model suitable for use in upward or downward flow lines

Enhancement of downward-facing saturated boiling heat transfer by the cold spray technique

Energy Technology Data Exchange (ETDEWEB)

Sohag, Frauk A.; Beck, Faith R.; Mohanta, Lokanath; Cheung, Fan Bill; Segall, Albert E.; Eden, Timothy J.; Potter, John K. [Pennsylvania State University, University Park (United States)

2017-02-15

In-vessel retention by passive external reactor vessel cooling under severe accident conditions is a viable approach for retention of radioactive core melt within the reactor vessel. In this study, a new and versatile coating technique known as 'cold spray' that can readily be applied to operating and advanced reactors was developed to form a microporous coating on the outer surface of a simulated reactor lower head. Quenching experiments were performed under simulated in-vessel retention by passive external reactor vessel cooling conditions using test vessels with and without cold spray coatings. Quantitative measurements show that for all angular locations on the vessel outer surface, the local critical heat flux (CHF) values for the coated vessel were consistently higher than the corresponding CHF values for the bare vessel. However, it was also observed for both coated and uncoated surfaces that the local rate of boiling and local CHF limit vary appreciably along the outer surface of the test vessel. Nonetheless, results of this intriguing study clearly show that the use of cold spray coatings could enhance the local CHF limit for downward-facing boiling by > 88%.

Downward continuation and tilt derivative of magnetic data for ...

Indian Academy of Sciences (India)

S K Pal

2017-06-12

Jun 12, 2017 ... Downward continuation; tilt derivative; magnetic data; coal fire mapping; Jharia coal field;. India. 1. .... of seams are thin and not suitable for mining but have the ...... Theory and Application; McGraw Hill Education (India).

Downward economic mobility and preterm birth: an exploratory study of Chicago-born upper class White mothers.

Science.gov (United States)

Collins, James W; Rankin, Kristin M; David, Richard J

2015-07-01

A paucity of published data exists on the factors underlying the relatively poor birth outcome of non-Hispanic White women in the United States. To determine whether downward economic mobility is a risk factor for preterm birth (births of Chicago-born upper-class (defined by early-life residence in affluent neighborhoods) non-Hispanic White women. Upper class-born White women (n = 4,891) who did not experience downward economic mobility by the time of delivery had a PTB rate of 5.4 %. Those women who experienced slight (n = 5,112), moderate (n = 2,158), or extreme (n = 339) downward economic mobility had PTB rates of 6.5, 8.5, and 10.1 %, respectively; RR (95 % CI) = 1.2 (1.0-4.0), 1.6 (1.3-1.9), and 1.9 (1.3-2.6), respectively. Maternal downward economic mobility was also associated with an increased prevalence of biologic, medical, and behavioral risk factors. Interestingly, the relationship between moderate to extreme downward mobility and preterm birth was stronger among former low birth weight (birth for former LBW and non-LBW women who experienced any downward mobility (compared to those women with lifelong upper class status) equaled 2.4 (1.1-5.3) and 1.1 (1.0-1.1), respectively. Downward economic mobility is associated with an increased risk of preterm birth among upper class-born White urban women; this phenomenon is strongest among former low birth weight women.

New data on two-phase water-air hydrodynamics in vertical upward and downward tubes

Energy Technology Data Exchange (ETDEWEB)

Lau, V [Atomic Energy of Canada Ltd., Saskatoon, SK (Canada); Rezkallah, K S [Saskatchewan Univ., Saskatoon (Canada). Mechanical Engineering Dept.

1996-12-31

The three key parameters involved in the analysis of the hydrodynamic characteristics of a two-phase system (i.e. pressure drop, void fraction, and flow pattern associated with the flow) are taken in vertical upward and downward tubes, using water-air mixture at atmospheric pressure. The acquired data set covers a wide range of liquid and gas flow rates, as well as void fractions. Using the acquired data set, two sets of flow pattern maps, for both upward and downward flows, are developed in the present study. Furthermore, a set of correlations for predicting the frictional pressure drop in both upward and downward flow were also developed. (author). 16 refs., 13 figs.

Flexible Consumers Reserving Electricity and Offering Profitable Downward Regulation

NARCIS (Netherlands)

N.F. Höning (Nicolas); J.A. La Poutré (Han); K. Strunz

2012-01-01

htmlabstractPrevious work on demand response in smart grids considers dynamic real-time prices, but has so far neglected to consider how consumers can also be involved in planning ahead, both for scheduling of consumption and reserving their ability to regulate downward during balancing. This work

Study of natural energy system and downward atmospheric radiation. Part 1. Outline on measurement and result on downward atmospheric radiation; Shizen energy system to tenku hosharyo no kansoku kenkyu. 1. Kisho kansoku gaiyo to tenku hosharyo no kansoku kekka

Energy Technology Data Exchange (ETDEWEB)

Ohashi, K [Kogakuin University, Tokyo (Japan); Masuoka, Y [Yokogawa Architects and Engineers, Inc., Tokyo (Japan)

1996-10-27

For the study of a natural energy system taking advantage of radiation cooling, a simplified method for estimating downward atmospheric radiation quantities was examined, using observation records supplied from Hachioji City, Aerological Observatory in Tsukuba City, and four other locations. Downward atmospheric radiation quantities are closely related to partial vapor pressure in the atmosphere. Because partial vapor pressure changes according to the season, it was classified into two, for summer and for winter, and was referred to downward atmospheric radiation quantities for the establishment of their correlationships. Downward atmospheric radiation quantities were predicted on the basis of meteorological factors such as partial vapor pressure and free air temperature. Accuracy was examined of the simplified estimation equation for downward atmospheric radiation that had been proposed. A multiple regression analysis was carried out for calculating constants for the estimation equation, using partial vapor pressure, Stefan-Boltzmann constant, and free air dry-bulb absolute temperature, all closely correlated with atmospheric downward radiation quantities. Accuracy improved by time-based classification. At night, use of SAT (equivalent free air temperature) produced more accurate estimation. Though dependent upon local characteristics of the observation spot, the estimation equation works effectively. 10 refs., 10 figs., 3 tabs.

The Aggregate Supply Curve: Keynes and Downwardly Sticky Money Wages.

Science.gov (United States)

Wells, Paul

1985-01-01

Keynes's explanation of both the rationale underlying downwardly sticky money wages and the consequences this phenomenon has for macroeconomic theory are reviewed. An aggregate supply curve appropriate to today's economy is then interpreted. (Author/RM)

Monthly version of HadISST sea surface temperature state-space components

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — State-Space Decomposition of Monthly version of HadISST sea surface temperature component (1-degree). See Rayner, N. A., Parker, D. E., Horton, E. B., Folland, C....

Characteristics of Eurasian snowmelt and its impacts on the land surface and surface climate

Science.gov (United States)

Ye, Kunhui; Lau, Ngar-Cheung

2018-03-01

The local hydrological and climatic impacts of Eurasian snowmelt are studied using advanced land surface and atmospheric data. It is found that intense melting of snow is located at mid-high latitudes in April and May. Snowmelt plays an important role in determining the seasonal cycles of surface runoff and soil moisture (SM). Specifically, melting is accompanied by sharp responses in surface runoff and surface SM while the impacts are delayed for deeper-layer of soil. This is particularly significant in the western sector of Eurasia. On interannual timescales, the responses of various surface parameters to snowmelt in the same month are rather significant. However, the persistence of surface SM anomalies is weak due to the strong soil evaporation anomalies and surplus of surface energy for evaporation. Strong impacts on the sensible heat flux, planetary boundary layer height and precipitation in the next month following the melting of snow are identified in west Russia and Siberia. Downward propagation of surface SM anomalies is observed and a positive evaporation-convection feedback is identified in west Russia. However, the subsequent impacts on the local convective precipitation in late spring-summer and its contribution to the total precipitation are seemingly weak. The atmospheric water vapor convergence has strong control over the total precipitation anomalies. Overall, snowmelt-produced SM anomalies are not found to significantly impact the late spring-summer local climate anomalies in Northern Eurasia. Therefore, the delayed remote-responses of atmospheric circulation and climate to the melting of Eurasian snow may be only possible near the melting period.

Extended Reconstructed Sea Surface Temperature (ERSST) Monthly Analysis, Version 3b

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Version 3b (v3b) of the Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a monthly SST analysis on a 2-degree global grid based on the International...

Using Satellites to Investigate the Sensitivity of Longwave Downward Radiation to Water Vapor at High Elevations

Science.gov (United States)

Naud, Catherine M.; Miller, James R.; Landry, Chris

2012-01-01

Many studies suggest that high-elevation regions may be among the most sensitive to future climate change. However, in situ observations in these often remote locations are too sparse to determine the feedbacks responsible for enhanced warming rates. One of these feedbacks is associated with the sensitivity of longwave downward radiation (LDR) to changes in water vapor, with the sensitivity being particularly large in many high-elevation regions where the average water vapor is often low. We show that satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) can be used to expand the current ground-based observational database and that the monthly averaged clear-sky satellite estimates of humidity and LDR are in good agreement with the well-instrumented Center for Snow and Avalanche Studies ground-based site in the southwestern Colorado Rocky Mountains. The relationship between MODIS-retrieved precipitable water vapor and surface specific humidity across the contiguous United States was found to be similar to that previously found for the Alps. More important, we show that satellites capture the nonlinear relationship between LDR and water vapor and confirm that LDR is especially sensitive to changes in water vapor at high elevations in several midlatitude mountain ranges. Because the global population depends on adequate fresh water, much of which has its source in high mountains, it is critically important to understand how climate will change there. We demonstrate that satellites can be used to investigate these feedbacks in high-elevation regions where the coverage of surface-based observations is insufficient to do so.

Monthly Sea Surface Salinity and Freshwater Flux Monitoring

Science.gov (United States)

Ren, L.; Xie, P.; Wu, S.

2017-12-01

Taking advantages of the complementary nature of the Sea Surface Salinity (SSS) measurements from the in-situ (CTDs, shipboard, Argo floats, etc.) and satellite retrievals from Soil Moisture Ocean Salinity (SMOS) satellite of the European Space Agency (ESA), the Aquarius of a joint venture between US and Argentina, and the Soil Moisture Active Passive (SMAP) of national Aeronautics and Space Administration (NASA), a technique is developed at NOAA/NCEP/CPC to construct an analysis of monthly SSS, called the NOAA Blended Analysis of Sea-Surface Salinity (BASS). The algorithm is a two-steps approach, i.e. to remove the bias in the satellite data through Probability Density Function (PDF) matching against co-located in situ measurements; and then to combine the bias-corrected satellite data with the in situ measurements through the Optimal Interpolation (OI) method. The BASS SSS product is on a 1° by 1° grid over the global ocean for a 7-year period from 2010. Combined with the NOAA/NCEP/CPC CMORPH satellite precipitation (P) estimates and the Climate Forecast System Reanalysis (CFSR) evaporation (E) fields, a suite of monthly package of the SSS and oceanic freshwater flux (E and P) was developed to monitor the global oceanic water cycle and SSS on a monthly basis. The SSS in BASS product is a suite of long-term SSS and fresh water flux data sets with temporal homogeneity and inter-component consistency better suited for the examination of the long-term changes and monitoring. It presents complete spatial coverage and improved resolution and accuracy, which facilitates the diagnostic analysis of the relationship and co-variability among SSS, freshwater flux, mixed layer processes, oceanic circulation, and assimilation of SSS into global models. At the AGU meeting, we will provide more details on the CPC salinity and fresh water flux data package and its applications in the monitoring and analysis of SSS variations in association with the ENSO and other major climate

Experimental study on liquid velocity in upward and downward two-phase flows

International Nuclear Information System (INIS)

Sun, X.; Paranjape, S.; Kim, S.; Ozar, B.; Ishii, M.

2003-01-01

Local characteristics of the liquid phase in upward and downward air-water two-phase flows were experimentally investigated in a 50.8-mm inner-diameter round pipe. An integral Laser Doppler Anemometry (LDA) system was used to measure the axial liquid velocity and its fluctuations. No effect of the flow direction on the liquid velocity radial profile was observed in single-phase liquid benchmark experiments. Local multi-sensor conductivity probes were used to measure the radial profiles of the bubble velocity and the void fraction. The measurement results in the upward and downward two-phase flows are compared and discussed. The results in the downward flow demonstrated that the presence of the bubbles tended to flatten the liquid velocity radial profile, and the maximum liquid velocity could occur off the pipe centerline, in particular at relatively low flow rates. However, the maximum liquid velocity always occurred at the pipe center in the upward flow. Also, noticeable turbulence enhancement due to the bubbles in the two-phase flows was observed in the current experimental flow conditions. Furthermore, the distribution parameter and the void weighted area-averaged drift velocity were obtained based on the definitions

Monthly CO surface sources inventory based on the 2000-2001 MOPITT satellite data

Science.gov (United States)

Pétron, Gabrielle; Granier, Claire; Khattatov, Boris; Yudin, Valery; Lamarque, Jean-François; Emmons, Louisa; Gille, John; Edwards, David P.

2004-11-01

This paper presents results of the inverse modeling of carbon monoxide surface sources on a monthly and regional basis using the MOPITT (Measurement Of the Pollution In The Troposphere) CO retrievals. The targeted time period is from April 2000 to March 2001. A sequential and time-dependent inversion scheme is implemented to correct an a priori set of monthly mean CO sources. The a posteriori estimates for the total anthropogenic (fossil fuel + biofuel + biomass burning) surface sources of CO in TgCO/yr are 509 in Asia, 267 in Africa, 140 in North America, 90 in Europe and 84 in Central and South America. Inverting on a monthly scale allows one to assess a corrected seasonality specific to each source type and each region. Forward CTM simulations with the a posteriori emissions show a substantial improvement of the agreement between modeled CO and independent in situ observations.

DOWNWARD CATASTROPHE OF SOLAR MAGNETIC FLUX ROPES

Energy Technology Data Exchange (ETDEWEB)

Zhang, Quanhao; Wang, Yuming; Hu, Youqiu; Liu, Rui, E-mail: zhangqh@mail.ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China)

2016-07-10

2.5-dimensional time-dependent ideal magnetohydrodynamic (MHD) models in Cartesian coordinates were used in previous studies to seek MHD equilibria involving a magnetic flux rope embedded in a bipolar, partially open background field. As demonstrated by these studies, the equilibrium solutions of the system are separated into two branches: the flux rope sticks to the photosphere for solutions at the lower branch but is suspended in the corona for those at the upper branch. Moreover, a solution originally at the lower branch jumps to the upper, as the related control parameter increases and reaches a critical value, and the associated jump is here referred to as an upward catastrophe. The present paper advances these studies in three aspects. First, the magnetic field is changed to be force-free; the system still experiences an upward catastrophe with an increase in each control parameter. Second, under the force-free approximation, there also exists a downward catastrophe, characterized by the jump of a solution from the upper branch to the lower. Both catastrophes are irreversible processes connecting the two branches of equilibrium solutions so as to form a cycle. Finally, the magnetic energy in the numerical domain is calculated. It is found that there exists a magnetic energy release for both catastrophes. The Ampère's force, which vanishes everywhere for force-free fields, appears only during the catastrophes and does positive work, which serves as a major mechanism for the energy release. The implications of the downward catastrophe and its relevance to solar activities are briefly discussed.

DOWNWARD CATASTROPHE OF SOLAR MAGNETIC FLUX ROPES

International Nuclear Information System (INIS)

Zhang, Quanhao; Wang, Yuming; Hu, Youqiu; Liu, Rui

2016-01-01

2.5-dimensional time-dependent ideal magnetohydrodynamic (MHD) models in Cartesian coordinates were used in previous studies to seek MHD equilibria involving a magnetic flux rope embedded in a bipolar, partially open background field. As demonstrated by these studies, the equilibrium solutions of the system are separated into two branches: the flux rope sticks to the photosphere for solutions at the lower branch but is suspended in the corona for those at the upper branch. Moreover, a solution originally at the lower branch jumps to the upper, as the related control parameter increases and reaches a critical value, and the associated jump is here referred to as an upward catastrophe. The present paper advances these studies in three aspects. First, the magnetic field is changed to be force-free; the system still experiences an upward catastrophe with an increase in each control parameter. Second, under the force-free approximation, there also exists a downward catastrophe, characterized by the jump of a solution from the upper branch to the lower. Both catastrophes are irreversible processes connecting the two branches of equilibrium solutions so as to form a cycle. Finally, the magnetic energy in the numerical domain is calculated. It is found that there exists a magnetic energy release for both catastrophes. The Ampère's force, which vanishes everywhere for force-free fields, appears only during the catastrophes and does positive work, which serves as a major mechanism for the energy release. The implications of the downward catastrophe and its relevance to solar activities are briefly discussed.

Interfacial structures and area transport in upward and downward two-phase flow

International Nuclear Information System (INIS)

Paranjape, S. S.; Kim, S.; Ishii, M.; Kelly, J.

2003-01-01

An experimental study has been carried out for upward and downward two-phase flow to study local interfacial structures and interfacial area transport. The flow studied, is an adiabatic, air-water, co-current, two-phase flow, in 25.4 mm and 50.8 mm ID test sections. Flow regime map is obtained using the characteristic signals obtained from an impedance void meter, employing neural network based identification methodology. A four sensor conductivity probe is used to measure the local two phase flow parameters, in bubbly flow regime. The local profiles of these parameters as well as their axial development reveal the nature of the interfacial structures and the bubble interaction mechanisms occurring in the flow. Furthermore, this study provides a good database for the development of the interfacial area transport equation, which dynamically models the changes in the interfacial area along a flow field. An interfacial area transport equation is used for downward flow based on that developed for the upward flow, with certain modifications in the bubble interaction terms. The area averaged values of the interfacial area concentration are compared with those predicted by the interfacial area transport model. The differences in the interfacial structures and interfacial area transport in co-current downward and upward two-phase flows are studied

Downward social comparison and subjective well-being in late life: the moderating role of perceived control.

Science.gov (United States)

Stewart, Tara L; Chipperfield, Judith G; Ruthig, Joelle C; Heckhausen, Jutta

2013-01-01

Drawing from Heckhausen and Schulz's Motivational Theory of Life-span Development, this study examined perceived control as a moderator of the protective relationship between downward social comparison and subjective well-being among older adults. Community-dwelling older adults (N = 97, 63% female, ages 79-97) were interviewed in their own homes at three time-points over a nine-year period. Interviews assessed older adults' perceived control over daily tasks, their use of downward social comparison in response to task restriction, and their subjective well-being. Regression analyses yielded a significant interaction between downward social comparison and perceived control for three subjective well-being outcomes: life satisfaction, perceived stress, and depressive symptoms. Follow-up analyses revealed that downward social comparison was associated with greater subjective well-being at low levels of perceived control; but was unrelated to subjective well-being at high levels of perceived control. These findings corroborate Heckhausen and Schulz's theorized goal-opportunity congruence premise and have implications for quality-of-life interventions to assist community-dwelling older adults.

Optical progression characteristics of an interesting natural downward bipolar lightning flash

Science.gov (United States)

Chen, Luwen; Lu, Weitao; Zhang, Yijun; Wang, Daohong

2015-01-01

high-speed cameras, Lightning Attachment Process Observation Systems, and fast and slow electrical antennas, we documented a downward bipolar lightning flash that contained one first positive stroke with a peak current of 142 kA and five subsequent negative strokes hitting on a 90 m tall structure on 29 July 2010 in Guangzhou City, China. All the six strokes propagated along the same viewed channel established by the first positive return stroke. The leader which preceded the positive return stroke propagated downward without any branches at a two-dimensional (2-D) speed of 2.5 × 106 m/s. An upward connecting leader with a length of about 80 m was observed in response to the downward positive leader. The 10-90% risetimes of the return strokes' optical pulses ranged from 2.2 µs to 3.2 µs, while the widths from the 10% wavefront to the 50% wave tail ranged from 56.5 µs to 83.1 µs, and the half peak widths ranged from 53.4 µs to 81.6 µs. All the return strokes exhibited similar speeds, ranging from 1.0 × 108 m/s to 1.3 × 108 m/s. Each of the return strokes was followed by a continuing current stage (CC). The first positive stroke CC lasted more than 150 ms, much larger than all the subsequent negative stroke CC, ranging from 13 ms to 70 ms.

Evaluation and Comparison of the Processing Methods of Airborne Gravimetry Concerning the Errors Effects on Downward Continuation Results: Case Studies in Louisiana (USA) and the Tibetan Plateau (China).

Science.gov (United States)

Zhao, Qilong; Strykowski, Gabriel; Li, Jiancheng; Pan, Xiong; Xu, Xinyu

2017-05-25

Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The

Evaluation and Comparison of the Processing Methods of Airborne Gravimetry Concerning the Errors Effects on Downward Continuation Results: Case Studies in Louisiana (USA) and the Tibetan Plateau (China)

Science.gov (United States)

Zhao, Q.

2017-12-01

Gravity data gaps in mountainous areas are nowadays often filled in with the data from airborne gravity surveys. Because of the errors caused by the airborne gravimeter sensors, and because of rough flight conditions, such errors cannot be completely eliminated. The precision of the gravity disturbances generated by the airborne gravimetry is around 3-5 mgal. A major obstacle in using airborne gravimetry are the errors caused by the downward continuation. In order to improve the results the external high-accuracy gravity information e.g., from the surface data can be used for high frequency correction, while satellite information can be applying for low frequency correction. Surface data may be used to reduce the systematic errors, while regularization methods can reduce the random errors in downward continuation. Airborne gravity surveys are sometimes conducted in mountainous areas and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic errors generated by the method are close to the simulated values. In addition, we study the relationship between the downward continuation altitudes and the error effect. The

Comparison of the sensitivity of surface downward longwave radiation to changes in water vapor at two high elevation sites

International Nuclear Information System (INIS)

Chen, Yonghua; Naud, Catherine M; Rangwala, Imtiaz; Landry, Christopher C; Miller, James R

2014-01-01

Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 km apart horizontally and 348 m vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR–q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here. (letter)

Comparison of the Sensitivity of Surface Downward Longwave Radiation to Changes in Water Vapor at Two High Elevation Sites

Science.gov (United States)

Chen, Yonghua; Naud, Catherine M.; Rangwala, Imtiaz; Landry, Christopher C.; Miller, James R.

2014-01-01

Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 kilometers apart horizontally and 348 meters vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR-q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here.

Distribution characteristics of interfacial parameter in downward gas-liquid two-phase flow in vertical circular tube

International Nuclear Information System (INIS)

Liu Guoqiang; Yan Changqi; Tian Daogui; Sun Licheng

2014-01-01

Experimental study was performed on distribution characteristics of interfacial parameters of downward gas-liquid flow in a vertical circular tube with the measurement by a two-sensor optical fiber probe. The test section is a circular pipe with the inner diameter of 50 mm and the length of 2000 mm. The superficial velocities of the gas and the liquid phases cover the ranges of 0.004-0.077 m/s and 0.43-0.71 m/s, respectively. The results show that the distributions of the interfacial parameters in downward bubbly flows are quite different from those in upward bubbly flows. For the case of upward flow, the parameters present the 'wall-peak' or 'core-peak' distributions, but for the case of downward flow, they show 'wall-peak' or 'wide-peak' distributions. The average value of void fraction in vertical downward flow is about 119.6%-145.0% larger than that in upward flow, and the interfacial area concentration is about 18.8%-82.5% larger than that in upward flow. The distribution of interfacial parameters shows an obvious tendency of uniformity. (authors)

Observations of Magnetosphere-Ionosphere Coupling Processes in Jupiter's Downward Auroral Current Region

Science.gov (United States)

Clark, G. B.; Mauk, B.; Allegrini, F.; Bagenal, F.; Bolton, S. J.; Bunce, E. J.; Connerney, J. E. P.; Ebert, R. W.; Gershman, D. J.; Gladstone, R.; Haggerty, D. K.; Hospodarsky, G. B.; Kotsiaros, S.; Kollmann, P.; Kurth, W. S.; Levin, S.; McComas, D. J.; Paranicas, C.; Rymer, A. M.; Saur, J.; Szalay, J. R.; Tetrick, S.; Valek, P. W.

2017-12-01

Our view and understanding of Jupiter's auroral regions are ever-changing as Juno continues to map out this region with every auroral pass. For example, since last year's Fall AGU and the release of publications regarding the first perijove orbit, the Juno particles and fields teams have found direct evidence of parallel potential drops in addition to the stochastic broad energy distributions associated with the downward current auroral acceleration region. In this region, which appears to exist in an altitude range of 1.5-3 Jovian radii, the potential drops can reach as high as several megavolts. Associated with these potentials are anti-planetward electron angle beams, energetic ion conics and precipitating protons, oxygen and sulfur. Sometimes the potentials within the downward current region are structured such that they look like the inverted-V type distributions typically found in Earth's upward current region. This is true for both the ion and electron energy distributions. Other times, the parallel potentials appear to be intermittent or spatially structured in a way such that they do not look like the canonical diverging electrostatic potential structure. Furthermore, the parallel potentials vary grossly in spatial/temporal scale, peak voltage and associated parallel current density. Here, we present a comprehensive study of these structures in Jupiter's downward current region focusing on energetic particle measurements from Juno-JEDI.

Flow Boiling on a Downward-Facing Inclined Plane Wall of Core Catcher

International Nuclear Information System (INIS)

Kim, Hyoung Tak; Bang, Kwang Hyun; Suh, Jung Soo

2013-01-01

In order to investigate boiling behavior on downward-facing inclined heated wall prior to the CHF condition, an experiment was carried out with 1.2 m long rectangular channel, inclined by 10 .deg. from the horizontal plane. High speed video images showed that the bubbles were sliding along the heated wall, continuing to grow and combining with the bubbles growing at their nucleation sites in the downstream. These large bubbles continued to slide along the heated wall and formed elongated slug bubbles. Under this slug bubble thin liquid film layer on the heated wall was observed and this liquid film prevents the wall from dryout. The length, velocity and frequency of slug bubbles sliding on the heated wall were measured as a function of wall heat flux and these parameters were used to develop wall boiling model for inclined, downward-facing heated wall. One approach to achieve coolable state of molten core in a PWR-like reactor cavity during a severe accident is to retain the core melt on a so-called core catcher residing on the reactor cavity floor after its relocation from the reactor pressure vessel. The core melt retained in the core catcher is cooled by water coolant flowing in an inclined cooling channel underneath as well as the water pool overlaid on the melt layer. Two-phase flow boiling with downward-facing heated wall such as this core catcher cooling channel has drawn a special attention because this orientation of heated wall may reach boiling crisis at lower heat flux than that of a vertical or upward-facing heated wall. Nishikawa and Fujita, Howard and Mudawar, Qiu and Dhir have conducted experiments to study the effect of heater orientation on boiling heat transfer and CHF. SULTAN experiment was conducted to study inclined large-scale structure coolability by water in boiling natural convection. In this paper, high-speed visualization of boiling behavior on downward-facing heated wall inclined by 10 .deg. is presented and wall boiling model for the

Numerical Solutions of the Mean-Value Theorem: New Methods for Downward Continuation of Potential Fields

Science.gov (United States)

Zhang, Chong; Lü, Qingtian; Yan, Jiayong; Qi, Guang

2018-04-01

Downward continuation can enhance small-scale sources and improve resolution. Nevertheless, the common methods have disadvantages in obtaining optimal results because of divergence and instability. We derive the mean-value theorem for potential fields, which could be the theoretical basis of some data processing and interpretation. Based on numerical solutions of the mean-value theorem, we present the convergent and stable downward continuation methods by using the first-order vertical derivatives and their upward continuation. By applying one of our methods to both the synthetic and real cases, we show that our method is stable, convergent and accurate. Meanwhile, compared with the fast Fourier transform Taylor series method and the integrated second vertical derivative Taylor series method, our process has very little boundary effect and is still stable in noise. We find that the characters of the fading anomalies emerge properly in our downward continuation with respect to the original fields at the lower heights.

Decadal variability in core surface flows deduced from geomagnetic observatory monthly means

DEFF Research Database (Denmark)

Whaler, K. A.; Olsen, Nils; Finlay, Chris

2016-01-01

. On the annual to decadal timescale, the SV is generated primarily by advection in the fluid outer core. We demonstrate the utility of the revised monthly means by calculating models of the core surface advective flow between 1997 and 2013 directly from the SV data. One set of models assumes flow......Monthly means of the magnetic field measurements at ground observatories are a key data source for studying temporal changes of the core magnetic field. However, when they are calculated in the usual way, contributions of external (magnetospheric and ionospheric) origin may remain, which make them...... less favourable for studying the field generated by dynamo action in the core. We remove external field predictions, including a new way of characterising the magnetospheric ring current, from the data and then calculate revised monthly means using robust methods. The geomagnetic secular variation (SV...

Development of a Convective Heat Transfer Correlation of a Supercritical CO2 with Vertical Downward Flow in Circular Tubes

International Nuclear Information System (INIS)

Yoo, Tae Ho; Kim, Hwan Yeol; Bae, Yoon Yeong

2009-01-01

Pressure of coolant flowing through a SCWR core subchannel is supercritical and the heat transfer behavior is known to be quite different from those at a subcritical pressure. Therefore the heat transfer study in a supercritical pressure is required for the acquisition of a reliable heat transfer correlation. A downward flow as well as an upward flow occurs in a multi-pass reactor core. The heat transfer at a supercritical pressure in downward channel has been known to result in a quite different behavior from an upward flow. An experiment for a supercritical CO 2 flowing vertically downward in circular tubes with inner diameters of 6.32 mm and 9 mm was performed by using SPHINX(Supercritical Pressure Heat transfer Investigation for NeXt generation) at KAERI. The obtained test results are compared with the estimations from the existing correlations and an empirical formula for a downward flow is suggested

Removal of NAPLs from the unsaturated zone using steam: prevention of downward migration by injecting mixtures of steam and air

DEFF Research Database (Denmark)

Schmidt, R.; Gudbjerg, Jacob; Sonnenborg, Torben Obel

2002-01-01

injection technology is presented, where a mixture of steam and air was injected. In twodimensional experiments with unsaturated porous medium contaminated with nonaqueous phase liquids, it was demonstrated how injection of pure steam lead to severe downward migration. Similar experiments, where steam......Steam injection for remediation of porous media contaminated by nonaqueous phase liquids has been shown to be a potentially efficient technology. There is, however, concern that the technique may lead to downward migration of separate phase contaminant. In this work, a modification of the steam...... and air were injected simultaneously, resulted in practically no downward migration and still rapid cleanup was achieved. The processes responsible for the prevention of downward migration when injecting steam–air mixtures were analyzed using a nonisothermal multiphase flow and transport model. Hereby...

The onset of flow instability for a downward flow of a non-boiling heated liquid

International Nuclear Information System (INIS)

Babelli, Ibrahim; Ishii, Mamoru

1999-01-01

A procedure for predicting the onset of flow instability (OFI) in downward flows at low-pressure and low-flow conditions without boiling is presented in this paper. It is generally accepted that the onset of significant void in subcooled boiling precedes, and is a precondition to, the occurrence of static flow instability. A detailed analysis of the pressure drop components for a downward flow in a heated channel reveals the possibility of unstable transition from single-phase flow to high-quality two-phase flow, i.e., flow excursion. Low flow rate and high subcooling are the two important conditions for the occurrence of this type of instability. The unstable transition occurs when the resistance to the downward flow caused by local (orifice), frictional, and thermal expansion pressure drops equalizes the driving force of the gravitational pressure drop. The inclusion of the thermal expansion pressure drop is essential to account for this type of transition. Experimental data are yet to be produced to verify the prediction of the present analysis. (author)

A monthly quality assurance procedure for 3D surface imaging.

Science.gov (United States)

Wooten, H Omar; Klein, Eric E; Gokhroo, Garima; Santanam, Lakshmi

2010-12-21

A procedure for periodic quality assurance of a video surface imaging system is introduced. AlignRT is a video camera-based patient localization system that captures and compares images of a patient's topography to a DICOM-formatted external contour, then calculates shifts required to accurately reposition the patient. This technical note describes the tools and methods implemented in our department to verify correct and accurate operation of the AlignRT hardware and software components. The procedure described is performed monthly and complements a daily calibration of the system.

Downward continuation of airborne gravity data by means of the change of boundary approach

Science.gov (United States)

Mansi, A. H.; Capponi, M.; Sampietro, D.

2018-03-01

Within the modelling of gravity data, a common practice is the upward/downward continuation of the signal, i.e. the process of continuing the gravitational signal in the vertical direction away or closer to the sources, respectively. The gravity field, being a potential field, satisfies the Laplace's equation outside the masses and this means that it allows to unambiguously perform this analytical continuation only in a source-free domain. The analytical continuation problem has been solved both in the space and spectral domains by exploiting different algorithms. As well known, the downward continuation operator, differently from the upward one, is an unstable operator, due to its spectral characteristics similar to those of a high-pass filter, and several regularization methods have been proposed in order to stabilize it. In this work, an iterative procedure to downward/upward continue the gravity field observations, acquired at different altitudes, is proposed. This methodology is based on the change of boundary principle and it has been expressively thought for aerogravimetric observations for geophysical exploration purposes. Within this field of application, usually several simplifications can be applied, basically due to the specific characteristics of the airborne surveys which are usually flown at almost constant altitude as close as possible to the terrain. For instance, these characteristics, as shown in the present work, allow to perform the downward continuation without the need of any regularization. The goodness of the proposed methodology has been evaluated by means of a numerical test on real data, acquired in the South of Australia. The test shows that it is possible to move the aerogravimetric data, acquired along tracks with a maximum height difference of about 250 m, with accuracies of the order of 10^{-3} mGal.

Downward Slope Driving Control for Electric Powered Wheelchair Based on Capacitor Regenerative Brake

Science.gov (United States)

Seki, Hirokazu; Takahashi, Yoshiaki

This paper describes a novel capacitor regenerative braking control scheme of electric powered wheelchairs for efficient driving on downward slopes. An electric powered wheelchair, which generates the driving force by electric motors, is expected to be widely used as a mobility support system for elderly people and disabled people; however the energy efficiency has to be further improved because it is driven only by battery energy. This study proposes a capacitor regenerative braking circuit and two types of velocity control schemes with variable duty ratio. The proposed regenerative braking circuit is based on the step-up/down circuit with additional resistance and connects right and left motors in series in order to obtain a larger braking power. Some driving experiments on a practical downward slope show the effectiveness of the proposed control system.

Calibration and combination of monthly near-surface temperature and precipitation predictions over Europe

Science.gov (United States)

Rodrigues, Luis R. L.; Doblas-Reyes, Francisco J.; Coelho, Caio A. S.

2018-02-01

A Bayesian method known as the Forecast Assimilation (FA) was used to calibrate and combine monthly near-surface temperature and precipitation outputs from seasonal dynamical forecast systems. The simple multimodel (SMM), a method that combines predictions with equal weights, was used as a benchmark. This research focuses on Europe and adjacent regions for predictions initialized in May and November, covering the boreal summer and winter months. The forecast quality of the FA and SMM as well as the single seasonal dynamical forecast systems was assessed using deterministic and probabilistic measures. A non-parametric bootstrap method was used to account for the sampling uncertainty of the forecast quality measures. We show that the FA performs as well as or better than the SMM in regions where the dynamical forecast systems were able to represent the main modes of climate covariability. An illustration with the near-surface temperature over North Atlantic, the Mediterranean Sea and Middle-East in summer months associated with the well predicted first mode of climate covariability is offered. However, the main modes of climate covariability are not well represented in most situations discussed in this study as the seasonal dynamical forecast systems have limited skill when predicting the European climate. In these situations, the SMM performs better more often.

Flow regime, void fraction and interfacial area transport and characteristics of co-current downward two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Lokanathan, Manojkumar [School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, IN 47907-2088 (United States); Hibiki, Takashi [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907-2017 (United States)

2016-10-15

Highlights: • Downward flow regime maps and models were studied for 25.4 to 101.6 mm pipe diameters. • Effect of flow inlet on flow transition, void & interfacial area profile were studied. • Bubble void profiles were associated with the interfacial forces for downward flow. • Flow regime pressure drop and interfacial friction factor were studied. • The most applicable and accurate downward drift-flux correlation was determined. - Abstract: Downward two-phase flow is observed in light water reactor accident scenarios such as loss of coolant accident (LOCA) and loss of heat sink accident (LOHS) due to loss of feed water or a secondary pipe break. Hence, a comprehensive literature review has been performed for the co-current downward two-phase flow with information on the flow regime transitions and flow characteristics for each regime in the downward flow. The review compares the experimental data of the flow regime map and the current available transition models. Objectivity of the data varies on the method utilized as a certain degree of subjectivity is still present in the most objective method. Nevertheless, experimental data through subjective methods such as direct visualization or analysis of a wire mesh sensor (WMS) data were still studied in this review. Despite the wide range of flow regime data for numerous pipe sizes, a consensus was not reached for the effect of pipe sizes on flow regime transition. However, it is known that a larger pipe results in greater degree of coalescence at lower gas flow rates (Hibiki et al., 2004). The introduction of a flow straightener at the inlet led to less coring and fluid rotation and inevitably, reduced bubble coalescence. This also resulted in the disappearance of the kinematic shock wave phenomenon, contrary to an inlet without a flow straightener. The effect of flow inlet, flow location, pipe diameter and bubble interfacial forces on the radial distribution as well as bubble coalescence and breakup rate

Development of a Convective Heat Transfer Correlation of a Supercritical CO{sub 2} with Vertical Downward Flow in Circular Tubes

Energy Technology Data Exchange (ETDEWEB)

Yoo, Tae Ho; Kim, Hwan Yeol; Bae, Yoon Yeong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2009-05-15

Pressure of coolant flowing through a SCWR core subchannel is supercritical and the heat transfer behavior is known to be quite different from those at a subcritical pressure. Therefore the heat transfer study in a supercritical pressure is required for the acquisition of a reliable heat transfer correlation. A downward flow as well as an upward flow occurs in a multi-pass reactor core. The heat transfer at a supercritical pressure in downward channel has been known to result in a quite different behavior from an upward flow. An experiment for a supercritical CO{sub 2} flowing vertically downward in circular tubes with inner diameters of 6.32 mm and 9 mm was performed by using SPHINX(Supercritical Pressure Heat transfer Investigation for NeXt generation) at KAERI. The obtained test results are compared with the estimations from the existing correlations and an empirical formula for a downward flow is suggested.

Modelling monthly runoff generation processes following land use changes: groundwater–surface runoff interactions

Directory of Open Access Journals (Sweden)

M. Bari

2004-01-01

Full Text Available A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall–runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, 'Ernies' (control, fully forested and 'Lemon' (54% cleared are in a zone of mean annual rainfall of 725 mm, while 'Salmon' (control, fully forested and 'Wights' (100% cleared are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall–runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i immediately after clearing due to reduced evapotranspiration, and (ii through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i an upper zone unsaturated store, (ii a transient stream zone store, (ii a lower zone unsaturated store and (iv a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and

Homogenization of Tianjin monthly near-surface wind speed using RHtestsV4 for 1951-2014

Science.gov (United States)

Si, Peng; Luo, Chuanjun; Liang, Dongpo

2018-05-01

Historical Chinese surface meteorological records provided by the special fund for basic meteorological data from the National Meteorological Information Center (NMIC) were processed to produce accurate wind speed data. Monthly 2-min near-surface wind speeds from 13 observation stations in Tianjin covering 1951-2014 were homogenized using RHtestV4 combined with their metadata. Results indicate that 10 stations had significant breakpoints—77% of the Tianjin stations—suggesting that inhomogeneity was common in the Tianjin wind speed series. Instrument change accounted for most changes, based on the metadata, including changes in type and height, especially for the instrument type. Average positive quantile matching (QM) adjustments were more than negative adjustments at 10 stations; positive biases with a probability density of 0.2 or more were mainly concentrates in the range 0.2 m s-1 to 1.2 m s-1, while the corresponding negative biases were mainly in the range -0.1 to -1.2 m s-1. Here, changes in variances and trends in the monthly mean surface wind speed series at 10 stations before and after adjustment were compared. Climate characteristics of wind speed in Tianjin were more reasonably reflected by the adjusted data; inhomogeneity in wind speed series was largely corrected. Moreover, error analysis reveals that there was a high consistency between the two datasets here and that from the NMIC, with the latter as the reference. The adjusted monthly near-surface wind speed series shows a certain reliability for the period 1951-2014 in Tianjin.

Premature and stable critical heat flux for downward flow in a narrow rectangular channel

International Nuclear Information System (INIS)

Lee, Juhyung; Chang, Soon Heung; Jeong, Yong Hoon; Jo, Daeseong

2014-01-01

It has been recommended that RRs and MTRs be designed to have sufficient margins for CHF and the onset of FI as well, since unstable flow could leads to premature CHF under very low wall heat flux in comparison to stable CHF. Even the fact and previous studies, however, the understanding of relationship among FI, premature CHF and stable CHF is not sufficient to date. In this regards, subcooled flow boiling in a vertical rectangular channel was experimentally investigated to enhance the understanding of the CHF and the effect of the two-phase flow instability on it under low pressure conditions, especially for downward flow which was adopted for Jordan Research and Training Reactor (JRTR) and Kijang research reactor (KJRR) to achieve easier fuel and irradiation rig loading. In this study, CHF for downward flow of water under low pressure in narrow rectangular channel was experimentally investigated. For conditions such as downward flow, narrow rectangular channel and low pressure, it has been deduced from literature that flow instability could largely influence on triggering CHF at lower heat flux, i. e. premature CHF. Total 54 CHF data, which includes premature and stable data was obtained for various fluid conditions and system configurations including inlet stiffness. The upper and lower boundaries of CHF were newly proposed based on the experiment

Steady-state subcooled nucleate boiling on a downward facing hemispherical surface

International Nuclear Information System (INIS)

Haddad, K.H.; Cheung, F.B.

1996-01-01

Steady-state nucleate boiling heat transfer experiments in saturated and subcooled water were conducted. The heating surface was a 0.305 m hemispherical aluminum vessel heated from the inside with water boiling on the outside. It was found that subcooling had very little effect on the nucleate boiling curve in the high heat flux regime where latent heat transport dominated. On the other hand, a relatively large effect of subcooling was observed in the low heat flux regime where sensible heat transport was important. Photographic records of the boiling phenomenon and the bubble dynamics indicated that in the high heat flux regime, boiling in the bottom center region of the vessel was cyclic in nature with a liquid heating phase, a bubble nucleation and growth phase, a bubble coalescence phase, and a large vapor mass ejection phase. At the same heat flux level, the size of the vapor masses was found to decrease from the bottom center toward the upper edge of the vessel, which was consistent with the observed increase in the critical heat flux in the flow direction along the curved heating surface

Downward Price-Based Brand Line Extensions Effects on Luxury Brands

OpenAIRE

Royo-Vela, Marcelo; Voss, Eileen

2015-01-01

This study tries to examine the brand concept consistency, the self-concept congruence and the resulting loyalty status of the consumers in order to evaluate whether a downward price-based line extensions in the luxury goods market has any negative or positive effect on them. By conducting focus group and in-depth interviews it was tried to filter out how brand concepts of luxury brands are perceived before and after a line extension. Results revealed that a crucial aspect for the evaluation ...

Modelling monthly runoff generation processes following land use changes: groundwater-surface runoff interactions

Science.gov (United States)

Bari, M.; Smettem, K. R. J.

A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, "Ernies" (control, fully forested) and "Lemon" (54% cleared) are in a zone of mean annual rainfall of 725 mm, while "Salmon" (control, fully forested) and "Wights" (100% cleared) are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall-runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i) an upper zone unsaturated store, (ii) a transient stream zone store, (ii) a lower zone unsaturated store and (iv) a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and predicted

Surface Weather Observations Monthly

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Surface Weather Observation 1001 Forms is a set of historical manuscript records for the period 1893-1948. The collection includes two very similar form types: Form...

Iterative Spherical Downward Continuation Applied to Magnetic and Gravitational Data from Satellite

Czech Academy of Sciences Publication Activity Database

Sebera, J.; Šprlák, M.; Novák, P.; Bezděk, Aleš; Valko, M.

2014-01-01

Roč. 35, č. 4 (2014), s. 941-958 ISSN 0169-3298 R&D Projects: GA MŠk LH13071 Grant - others:ESA(XE) AO/1-6367/10/NL/AF Institutional support: RVO:67985815 Keywords : downward continuation * Earth's gravitational and magnetic field * poisson integral equation Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 3.447, year: 2014

ENSO surface shortwave radiation forcing over the tropical Pacific

Directory of Open Access Journals (Sweden)

K. G. Pavlakis

2008-09-01

Full Text Available We have studied the spatial and temporal variation of the downward shortwave radiation (DSR at the surface of the Earth during ENSO events for a 21-year period over the tropical and subtropical Pacific Ocean (40° S–40° N, 90° E–75° W. The fluxes were computed using a deterministic model for atmospheric radiation transfer, along with satellite data from the ISCCP-D2 database, reanalysis data from NCEP/NCAR for the key atmospheric and surface input parameters, and aerosol parameters from GADS (acronyms explained in main text. A clear anti-correlation was found between the downward shortwave radiation anomaly (DSR-A time-series, in the region 7° S–5° N 160° E–160° W located west of the Niño-3.4 region, and the Niño-3.4 index time-series. In this region where the highest in absolute value DSR anomalies are observed, the mean DSR anomaly values range from −45 Wm⁻² during El Niño episodes to +40 Wm⁻² during La Niña events. Within the Niño-3.4 region no significant DSR anomalies are observed during the cold ENSO phase in contrast to the warm ENSO phase. A high correlation was also found over the western Pacific (10° S–5° N, 120–140° E, where the mean DSR anomaly values range from +20 Wm⁻² to −20 Wm⁻² during El Niño and La Niña episodes, respectively. There is also convincing evidence that the time series of the mean downward shortwave radiation anomaly in the off-equatorial western Pacific region 7–15° N 150–170° E, precedes the Niño-3.4 index time-series by about 7 months and the pattern of this anomaly is indicative of ENSO operating through the mechanism of the western Pacific oscillator. Thus, the downward shortwave radiation anomaly is a complementary index to the SST anomaly for the study of ENSO events and can be used to assess whether or not El Niño or La Niña conditions prevail.

Effect of reflective surfaces on a greenhouse lettuce crop

Energy Technology Data Exchange (ETDEWEB)

Warman, P.R.; Mayhew, W.J.

1979-01-01

The Canadian greenhouse industry is an important segment of horticultural production, providing employment for thousands of people. Continuing increases in the costs of conventional fuel supplies, however, has placed the industry in some jeopardy since the cost of heating during the winter months is also escalating. In response to this problem the Brace Research Institute has developed a single roofed greenhouse designed to capture and store the sun's energy, and to increase the amount of downward solar radiation inside the greenhouse through the use of specularly-reflecting back and side walls. The research investigated the effect of a reflective surface on plant growth, development, and nutritional uptake during fall and the early months of winter. The inside walls of the greenhouse were lined with aluminized polyester to act as a reflective surface and flat black roofing felt paper to provide a non-reflecting surface. Grand Rapids Forcing lettuce was planted from seed into a peat-vermiculite bed and total solar radiation was monitored on the horizontal. Over the duration of the experiment, the reflective side of the greenhouse received more than twice as much solar radiation as the non-reflective side leading to significantly larger plant yields on the reflective side. There were no significant differences in the uptake of the plant macronutrients, N, P, K, Ca, and Mg.

Void fraction in steam-water mixture downward motion in tubes and intertubular spaces

International Nuclear Information System (INIS)

Miropol'skij, Z.L.; Shneerova, R.I.; Karamysheva, A.I.

1978-01-01

Experiments have been carried out with a view to determining the averaged cross-section virtual steam contents for downward steam-air mixture flows in a pipe (diameter 40 mm, length 600 mm) and in a 400 mm-long cylindrical channel, which accomodated 19 cylindrical tubes. Equivalent channel diameter was 9.2 mm. The tests were carried out both under adiabatic flow conditions and in the presence of heat transfer through pipes, which were electrically heated. The p pressure was 3 mPa, specific heat fluxes g=0-0.27 MW/m 2 , mass rates wsub(p)=110-395 kg/m 2 xs in the tube bunch and 95-345 kg/m 2 xs in the pipe. The test results indicate that: the virtual volumetric steam contents in a downward flow of a steam-air mixture are higher than those in an upward flow; x in a tube bunch is substantially smaller than that in a pipe

An Experimental Study on the Onset of Nucleate Boiling in Narrow Rectangular Channels for Downward Flow

International Nuclear Information System (INIS)

Song, Jung-Hyun; Lee, Juhyung; Jeong, Yong Hoon; Chang, Soon Heung

2014-01-01

As the research reactors operates with downward flow, they have some advantages; downward flow can reduce the radioisotopes in the upper part of research reactor and simplify the locking mechanism as countervailing the buoyancy force on the nuclear fuel. However, as the research reactor operates under the low pressure condition, the premature critical heat flux (CHF) can occur during the onset of flow instability (OFI) according to circumstances as the pressure fluctuates significantly. For that reason, it is important to know and set the margin for the onset of nucleate boiling (ONB) which is the preceding phenomena of OFI and CHF to predict and handle with OFI. In addition, research reactor is the nuclear reactor serves neutron source for many research fields such as neutron scattering, non-destructive testing, radioisotope treatment and so on, it is important to avoid ONB to get stable neutron source. IAEA also recommends for research reactors to have enough ONB margin to maintain the normal operation state in 'IAEA-TECDOC-233' (1980). Though the ONB in research reactor is emphasized for these reasons, there isn't sufficient ONB data under downward flow condition and no ONB prediction correlation for downward flow as well. In addition, in many researches; Mosyak et al., Hapke et al., Wu et al. and Hong et al., the existing ONB correlations are not suitable for narrow rectangular channel. In the present work, not only a new ONB prediction correlation would be developed, but also comparison between new correlation with several ONB correlations would be shown. In this paper, ONB data would be analyzed to develop new ONB prediction correlation

BABCOCK–LEIGHTON SOLAR DYNAMO: THE ROLE OF DOWNWARD PUMPING AND THE EQUATORWARD PROPAGATION OF ACTIVITY

International Nuclear Information System (INIS)

Karak, Bidya Binay; Cameron, Robert

2016-01-01

The key elements of the Babcock–Leighton dynamos are the generation of poloidal field through decay and the dispersal of tilted bipolar active regions and the generation of toroidal field through the observed differential rotation. These models are traditionally known as flux transport dynamo models as the equatorward propagations of the butterfly wings in these models are produced due to an equatorward flow at the bottom of the convection zone. Here we investigate the role of downward magnetic pumping near the surface using a kinematic Babcock–Leighton model. We find that the pumping causes the poloidal field to become predominately radial in the near-surface shear layer, which allows the negative radial shear to effectively act on the radial field to produce a toroidal field. We observe a clear equatorward migration of the toroidal field at low latitudes as a consequence of the dynamo wave even when there is no meridional flow in the deep convection zone. Both the dynamo wave and the flux transport type solutions are thus able to reproduce some of the observed features of the solar cycle including the 11-year periodicity. The main difference between the two types of solutions is the strength of the Babcock–Leighton source required to produce the dynamo action. A second consequence of the magnetic pumping is that it suppresses the diffusion of fields through the surface, which helps to allow an 11-year cycle at (moderately) larger values of magnetic diffusivity than have previously been used.

BABCOCK–LEIGHTON SOLAR DYNAMO: THE ROLE OF DOWNWARD PUMPING AND THE EQUATORWARD PROPAGATION OF ACTIVITY

Energy Technology Data Exchange (ETDEWEB)

Karak, Bidya Binay; Cameron, Robert, E-mail: bkarak@ucar.edu [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

2016-11-20

The key elements of the Babcock–Leighton dynamos are the generation of poloidal field through decay and the dispersal of tilted bipolar active regions and the generation of toroidal field through the observed differential rotation. These models are traditionally known as flux transport dynamo models as the equatorward propagations of the butterfly wings in these models are produced due to an equatorward flow at the bottom of the convection zone. Here we investigate the role of downward magnetic pumping near the surface using a kinematic Babcock–Leighton model. We find that the pumping causes the poloidal field to become predominately radial in the near-surface shear layer, which allows the negative radial shear to effectively act on the radial field to produce a toroidal field. We observe a clear equatorward migration of the toroidal field at low latitudes as a consequence of the dynamo wave even when there is no meridional flow in the deep convection zone. Both the dynamo wave and the flux transport type solutions are thus able to reproduce some of the observed features of the solar cycle including the 11-year periodicity. The main difference between the two types of solutions is the strength of the Babcock–Leighton source required to produce the dynamo action. A second consequence of the magnetic pumping is that it suppresses the diffusion of fields through the surface, which helps to allow an 11-year cycle at (moderately) larger values of magnetic diffusivity than have previously been used.

Are insecure jobs as bad for mental health and occupational commitment as unemployment? Equal threat or downward spiral

Directory of Open Access Journals (Sweden)

Kathleen Otto

2014-01-01

Full Text Available We investigated the significance of unemployment and job insecurity for mental health (self-esteem; life satisfaction and occupational commitment (occupational self-efficacy; affective occupational commitment comparing the "equal threat" assumption with the "downward spiral" assumption. Whereas the equal threat model suggests that unemployment and (perceived insecure employment are similarly threatening phenomena, the downward spiral model assumes that there might be a spectrum of employment insecurity, ranging from secure employment to long-term unemployment, that is associated with decreasing mental health and occupational commitment. Controlling for socio-demographic background variables and personality traits, results of ANCOVAs, in which we distinguished between workers who were (more or less securely employed and those who were either insecurely employed or short- or long-term unemployed revealed that the insecurely employed workers were no better off than those who were (short-term unemployed - in line with the equal threat hypothesis. Only for occupational self-efficacy did we find some support for the downward spiral model.

Satellite Based Downward Long Wave Radiation by Various Models in Northeast Asia

Directory of Open Access Journals (Sweden)

Chanyang Sur

2014-01-01

Full Text Available Satellite-based downward long wave radiation measurement under clear sky conditions in Northeast Asia was conducted using five well-known physical models (Brunt 1932, Idso and Jackson 1969, Brutsaert 1975, Satterlund 1979, Prata 1996 with a newly proposed global Rld model (Abramowitz et al. 2012. Data from two flux towers in South Korea were used to validate downward long wave radiation. Moderate resolution imaging spectroradiometer (MODIS atmospheric profile products were used to develop the Rld models. The overall root mean square error (RMSE of MODIS Rld with respect to two ecosystem-type flux towers was determined to be ≈ 20 W m-2. Based on the statistical analyses, MODIS Rld estimates with Brutsaert (1975 and Abramowitz et al. (2012 models were the most applicable for evaluating Rld for clear sky conditions in Northeast Asia. The Abramowitz Rld maps with MODIS Ta and ea showed reasonable seasonal patterns, which were well-aligned with other biophysical variables reported by previous studies. The MODIS Rld map developed in this study will be very useful for identifying spatial patterns that are not detectable from ground-based Rld measurement sites.

DOWNWARD SLOPING DEMAND CURVES FOR STOCK AND LEVERAGE

Directory of Open Access Journals (Sweden)

Liem Pei Fun

2006-01-01

Full Text Available This research attempts to investigate the effect of downward sloping demand curves for stock on firms' financing decisions. For the same size of equity issuance, firms with steeper slope of demand curves for their stocks experience a larger price drop in their share price compare to their counterparts. As a consequence, firms with a steeper slope of demand curves are less likely to issue equity and hence they have higher leverage ratios. This research finds that the steeper the slope of demand curve for firm's stock, the higher the actual leverage of the firm. Furthermore, firms with a steeper slope of demand curves have higher target leverage ratios, signifying that these firms prefer debt to equity financing in order to avoid the adverse price impact of equity issuance on their share price.

Downward migration of radiocesium in an abandoned paddy soil after the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Takahashi, Junko; Wakabayashi, Shokichi; Tamura, Kenji; Onda, Yuichi

2018-02-01

After the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011, continuous monitoring of the detailed vertical distribution of radiocesium in soil is required to evaluate the fate of radiocesium and establish strategies for remediation and management of the contaminated land. It is especially important to investigate paddy soil because little knowledge has been accumulated for paddy soil and wetland rice is a major staple in Japan. Therefore, we monitored the vertical distribution of 137 Cs in abandoned paddy soil in a planned evacuation zone from June 2011 to March 2016. The decontamination works (i.e., 5 cm of surface soil removal and re-covering with uncontaminated soil) were conducted by the government in 2015. As a result of monitoring, the 137 Cs gradually migrated downward with time and the 137 Cs concentration in the 0-10 cm soil was almost homogenous in October 2014, although it was non-cultivated. The liner relationship was obtained between the median depth, which is the thickness of a soil layer containing half of the total 137 Cs inventory, and the time after the accident, indicating the migration rate was constant (1.3 cm y -1 ) before the decontamination works. After the decontamination works, the 137 Cs concentration in the uppermost surface layer was reduced by 90%, however the total 137 Cs inventory was reduced by only 50-70%. It was shown that the efficiency of 137 Cs removal by the decontamination works decrease linearly over time in fields like the studied paddy, in which the homogenization of 137 Cs concentration occurred. Conversely, the downward migration of 137 Cs to subsurface layers deeper than 10 cm (i.e., plowpan layer) with low permeability rarely occurred. It is expected that these unique trends in distribution and migration of 137 Cs would be found in abandoned paddy soils with properties similar to the studied soil, sandy loam but poorly drained because of the low permeable plowpan layer, although further validation is

Creating a monthly time series of the potentiometric surface in the Upper Floridan aquifer, Northern Tampa Bay area, Florida, January 2000-December 2009

Science.gov (United States)

Lee, Terrie M.; Fouad, Geoffrey G.

2014-01-01

In Florida’s karst terrain, where groundwater and surface waters interact, a mapping time series of the potentiometric surface in the Upper Floridan aquifer offers a versatile metric for assessing the hydrologic condition of both the aquifer and overlying streams and wetlands. Long-term groundwater monitoring data were used to generate a monthly time series of potentiometric surfaces in the Upper Floridan aquifer over a 573-square-mile area of west-central Florida between January 2000 and December 2009. Recorded groundwater elevations were collated for 260 groundwater monitoring wells in the Northern Tampa Bay area, and a continuous time series of daily observations was created for 197 of the wells by estimating missing daily values through regression relations with other monitoring wells. Kriging was used to interpolate the monthly average potentiometric-surface elevation in the Upper Floridan aquifer over a decade. The mapping time series gives spatial and temporal coherence to groundwater monitoring data collected continuously over the decade by three different organizations, but at various frequencies. Further, the mapping time series describes the potentiometric surface beneath parts of six regionally important stream watersheds and 11 municipal well fields that collectively withdraw about 90 million gallons per day from the Upper Floridan aquifer. Monthly semivariogram models were developed using monthly average groundwater levels at wells. Kriging was used to interpolate the monthly average potentiometric-surface elevations and to quantify the uncertainty in the interpolated elevations. Drawdown of the potentiometric surface within well fields was likely the cause of a characteristic decrease and then increase in the observed semivariance with increasing lag distance. This characteristic made use of the hole effect model appropriate for describing the monthly semivariograms and the interpolated surfaces. Spatial variance reflected in the monthly

Dispersion of Exhalation Pollutants in a Two-bed Hospital Ward with a Downward Ventilation System

DEFF Research Database (Denmark)

Qian, Hua; Nielsen, Peter V.; Hyldgård, Carl-Erik

2006-01-01

The Centers for Disease Control and Prevention has recommended the use of downward ventilation systems in isolation rooms to reduce the risk of cross-infection from airborne transmissible diseases. The expected airflow pattern of a downward ventilation design would supply cooler and slightly...... to investigate the airflow pattern and pollutant dispersion in the test ward. Based on both experimental and numerical results, the laminar airflow pattern was shown to be impossible to achieve due to turbulent flow mixing and flow entrainment into the supply air stream. The thermal plumes produced above people...... were found to induce flow mixing. We also studied the effects of the locations of the supply and extraction openings on both the flow pattern and pollutant exposure level in the occupied zone. A number of practical recommendations are suggested....

An experimental study on the negative effects of downwards flow of the melted frost over a multi-circuit outdoor coil in an air source heat pump during reverse cycle defrosting

International Nuclear Information System (INIS)

Song, Mengjie; Pan, Dongmei; Li, Ning; Deng, Shiming

2015-01-01

Highlights: • A special experimental rig was built and its details are reported. • The negative effects of downwards flowing of the melted frost were shown. • Defrosting duration was shortened after installing water collecting trays. • Temperature of melted frost decreased after installing trays. - Abstract: When the surface temperature of the outdoor coil in an air source heat pump (ASHP) unit is lower than both freezing point of water and the air dew point, frost can be formed and accumulated over outdoor coil surface. Frosting affects the energy efficiency, and periodic defrosting therefore is necessary. Reverse cycle defrosting is currently the most widely used defrosting method. A previous related study has indicated that during reverse cycle defrosting, downwards flow of the melted frost over a multi-circuit outdoor coil could affect the defrosting performance, without however giving detailed quantitative analysis of the effects. Therefore an experimental study on the effects has been carried out and a quantitative analysis conducted using the experimental data. In this paper, the detailed description of an experimental ASHP unit which was specifically built up is firstly reported. This is followed by presenting experimental results. Result analysis and conclusions are finally given

Heating limits of boiling downward two-phase flow in parallel channels

International Nuclear Information System (INIS)

Fukuda, Kenji; Kondoh, Tetsuya; Hasegawa, Shu; Sakai, Takaaki.

1989-01-01

Flow characteristics and heating limits of downward two-phase flow in single or parallel multi-channels are investigated experimentally and analytically. The heating section used is made of glass tube, in which the heater tube is inserted, and the flow regime inside it is observed. In single channel experiments with low flow rate conditions, it is found that, initially, gas phase which flows upward against the downward liquid phase flow condenses and diminishes as it flows up being cooled by inflowing liquid. However, as the heating power is increased, some portion of the gas phase reaches the top and accumulates to form an liquid level, which eventually causes the dryout. On the other hand, for high flow rate condition, the flooding at the bottom of the heated section is the cause of the dryout. In parallel multi-channels experiments, reversed (upward) flow which leads to the dryout is observed in some of these channels for low flow rate conditions, while the situation is the same to the single channel case for high flow rate conditions. Analyses are carried out to predict the onset of dryout in single channel using the drift flux model as well as the Wallis' flooding correlation. Above-mentioned two types of the dryout and their boundary are predicted which agree well with the experimental results. (author)

On the Nocturnal Downward and Westward Equatorial Ionospheric Plasma Drifts During the 17 March 2015 Geomagnetic Storm

Science.gov (United States)

Bagiya, Mala S.; Vichare, Geeta; Sinha, A. K.; Sripathi, S.

2018-02-01

During quiet period, the nocturnal equatorial ionospheric plasma drifts eastward in the zonal direction and downward in the vertical direction. This quiet time drift pattern could be understood through dynamo processes in the nighttime equatorial ionosphere. The present case study reports the nocturnal simultaneous occurrence of the vertically downward and zonally westward plasma drifts over the Indian latitudes during the geomagnetic storm of 17 March 2015. After 17:00 UT ( 22:10 local time), the vertical plasma drift became downward and coincided with the westward zonal drift, a rarely observed feature of low latitude plasma drifts. The vertical drift turned upward after 18:00 UT, while the zonal drift became eastward. We mainly emphasize here the distinct bipolar type variations of vertical and zonal plasma drifts observed around 18:00 UT. We explain the vertical plasma drift in terms of the competing effects between the storm time prompt penetration and disturbance dynamo electric fields. Whereas, the westward drift is attributed to the storm time local electrodynamical changes mainly through the disturbance dynamo field in addition to the vertical Pedersen current arising from the spatial (longitudinal) gradient of the field aligned Pedersen conductivity.

Measurement of the rate of droplet deposition in vertical upward and downward annular flows

International Nuclear Information System (INIS)

Murakami, Toshihiro; Okawa, Tomio; Takei, Rei

2008-01-01

The deposition rate of droplets was measured for vertical annular two-phase flows in a small diameter tube by means of the double film extraction technique. The test section was a round tube of 5 mm in inside diameter, air and water were used as test fluids, and the flow direction was set to upward and downward; the system pressure and the flow rates of gas and liquid phases were changed parametrically. If the droplet velocity relative to the continuous gas phase is in the equilibrium state, the shear induced lift force acting on droplets is directed toward the tube centerline in upflow while toward the tube wall in downflow. Particular attention was therefore paid to the effect of flow direction. It was shown experimentally that the deposition rate of droplets in downward flow is greater than that in upward flow. The difference in the measured deposition rate may be attributed to the direction of lift force acting on droplets. (author)

Research Note : Near-surface layer replacement for sparse data: Is interpolation needed?

NARCIS (Netherlands)

Sun, Yimin; Verschuur, D.J.; Luo, Yi

2017-01-01

Near-surface problem is a common challenge faced by land seismic data processing, where often, due to near-surface anomalies, events of interest are obscured. One method to handle this challenge is near-surface layer replacement, which is a wavefield reconstruction process based on downward

Estimation of monthly solar exposure on horizontal surface by Angstrom-type regression equation

International Nuclear Information System (INIS)

Ravanshid, S.H.

1981-01-01

To obtain solar flux intensity, solar radiation measuring instruments are the best. In the absence of instrumental data there are other meteorological measurements which are related to solar energy and also it is possible to use empirical relationships to estimate solar flux intensit. One of these empirical relationships to estimate monthly averages of total solar radiation on a horizontal surface is the modified angstrom-type regression equation which has been employed in this report in order to estimate the solar flux intensity on a horizontal surface for Tehran. By comparing the results of this equation with four years measured valued by Tehran's meteorological weather station the values of meteorological constants (a,b) in the equation were obtained for Tehran. (author)

Quantum reflection in the linearly downward potential

Science.gov (United States)

Chamnan, N.; Krunavakarn, B.

2017-09-01

In this work, the motion of a particle in one dimension under the influence of the linearly downward potential well is studied within the context of the non-relativistic quantum mechanics. The attention is paid on the paradoxical phenomenon of the reflection of a particle that is in contrast between classical and quantum physics. Classically, the reflection effect occurs only at a potential barrier. To demonstrate such counter-intuitive phenomenon, the Schrödinger equation is solved to obtain the reflection coefficient in the scattering state by considering an incident particle that is represented by a monochromatic plane wave having an energy E > 0, propagates freely from left to right, pass through the potential well. The continuity conditions at boundaries give the desired result that is expressed in terms of the Airy functions which depends on the incident energy E, the strength jV 0 j and the range L of the well. The value of the reflection coefficient R lies in the interval 0 < R < 1, and its behavior is the decreasing function with respect to the range L.

Disappearance of the laue spots of the downward X-ray diffraction and huge recoil Thomson scattering in solid helium as some prominent peculiarities of a quantum crystal

Energy Technology Data Exchange (ETDEWEB)

Nakajima, Tetsuo

1996-02-01

In topographs of the downward X-ray diffraction, no Laue spots could be observed using a horizontally thin line-focussed beam. The disappearance of the Laue spots by the downward X-ray diffraction could be explained by two main factors besides a synergistic effect of the smallness of the atomic-scattering factors, the absorption coefficients, the densities etc. One is that the downward X-ray diffraction is completely inelastic scattering, and, as a result, diffracted X-ray beams may become entirely diffuse scattering. The other is that the great difference in the linear scatterer density between the forward and downward directions resulted from the fact that the irradiation of a line-focussed X-ray beam to take section topographs weakens the downward X-ray diffraction. The main reason is not due to the zero-point vibration. (J.P.N.).

Disappearance of the laue spots of the downward X-ray diffraction and huge recoil Thomson scattering in solid helium as some prominent peculiarities of a quantum crystal

International Nuclear Information System (INIS)

Nakajima, Tetsuo.

1996-02-01

In topographs of the downward X-ray diffraction, no Laue spots could be observed using a horizontally thin line-focussed beam. The disappearance of the Laue spots by the downward X-ray diffraction could be explained by two main factors besides a synergistic effect of the smallness of the atomic-scattering factors, the absorption coefficients, the densities etc. One is that the downward X-ray diffraction is completely inelastic scattering, and, as a result, diffracted X-ray beams may become entirely diffuse scattering. The other is that the great difference in the linear scatterer density between the forward and downward directions resulted from the fact that the irradiation of a line-focussed X-ray beam to take section topographs weakens the downward X-ray diffraction. The main reason is not due to the zero-point vibration. (J.P.N.)

Monthly Composite Raster Images for Sea Surface Temperature in the Gulf of Maine for Stellwagen Bank NMS

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of sea surface temperature (SST) in the Gulf of Maine. These raster images are monthly composites, and were...

Field measurement of albedo for limited extent test surfaces

Energy Technology Data Exchange (ETDEWEB)

Sailor, David J. [Portland State University, Department of Mechanical and Materials Engineering, P.O. Box 751-ME, Portland, OR 97207 (United States); Resh, Kyle; Segura, Del [Tulane University, Department of Mechanical Engineering, 400 Lindy Boggs Center, New Orleans, LA 70118 (United States)

2006-05-15

A new method is introduced for field measurement of surface albedo. This method consists of the use of a cylindrical shade ring made of opaque fabric with a known (low) albedo placed over a test surface. The albedo measurement is accomplished using two small pyranometers situated so that the downward-facing pyranometer receives radiation only from the test surface and the shade ring. The upward-facing pyranometer simultaneously records the incoming solar radiation. The radiation received by the downward-facing pyramometer is a combination of reflected radiation from shaded and unshaded portions of these two surfaces, requiring detailed accounting of the resulting view factor geometries. The method presented here improves upon past approaches by allowing for smaller sample sizes, minimizing errors associated with reflective properties of the surroundings, and allowing for accurate measurements even under partially cloudy skies. In addition to these methodological improvements we introduce an approach for estimating the uncertainty in the resulting albedo measurements. Results from field measurements are presented to validate the measurement protocol, and to compare its accuracy with the accuracy of a published standard. (author)

Unexpected high 35S concentration revealing strong downward transport of stratospheric air during the monsoon transitional period in East Asia

Science.gov (United States)

Lin, Mang; Zhang, Zhisheng; Su, Lin; Su, Binbin; Liu, Lanzhong; Tao, Jun; Fung, Jimmy C. H.; Thiemens, Mark H.

2016-03-01

October is the monsoon transitional period in East Asia (EA) involving a series of synoptic activities that may enhance the downward transport of stratospheric air to the planetary boundary layer (PBL). Here we use cosmogenic 35S in sulfate aerosols (35SO42-) as a tracer for air masses originating from the stratosphere and transported downward to quantify these mixing processes. From 1 year 35SO42- measurements (March 2014 to February 2015) at a background station in EA we find remarkably enhanced 35SO42- concentration (3150 atoms m-3) in October, the highest value ever reported for natural sulfate aerosols. A four-box 1-D model and meteorological analysis reveal that strong downward transport from the free troposphere is a vital process entraining aged stratospheric air masses to the PBL. The aged stratospheric masses are accumulated in the PBL, accelerating the SO2 transformation to SO42-. Implications for the tropospheric O3 budget and the CO2 biogeochemical cycle are discussed.

A unified engineering model of the first stroke in downward negative lightning

Science.gov (United States)

Nag, Amitabh; Rakov, Vladimir A.

2016-03-01

Each stroke in a negative cloud-to-ground lightning flash is composed of downward leader and upward return stroke processes, which are usually modeled individually. The first stroke leader is stepped and starts with preliminary breakdown (PB) which is often viewed as a separate process. We present the first unified engineering model for computing the electric field produced by a sequence of PB, stepped leader, and return stroke processes, serving to transport negative charge to ground. We assume that a negatively charged channel extends downward in a stepped fashion during both the PB and leader stages. Each step involves a current wave that propagates upward along the newly formed channel section. Once the leader attaches to ground, an upward propagating return stroke neutralizes the charge deposited along the channel. Model-predicted electric fields are in reasonably good agreement with simultaneous measurements at both near (hundreds of meters, electrostatic field component is dominant) and far (tens of kilometers, radiation field component is dominant) distances from the lightning channel. Relations between the features of computed electric field waveforms and model input parameters are examined. It appears that peak currents associated with PB pulses are similar to return stroke peak currents, and the observed variation of electric radiation field peaks produced by leader steps at different heights above ground is influenced by the ground corona space charge.

Regional difference of the vertical structure of seasonal thermocline and its impact on sea surface temperature in the North Pacific

Science.gov (United States)

Yamaguchi, R.; Suga, T.

2016-12-01

Recent observational studies show that, during the warming season, a large amount of heat flux is penetrated through the base of thin mixed layer by vertical eddy diffusion, in addition to penetration of solar radiation [1]. In order to understand this heat penetration process due to vertical eddy diffusivity and its contribution to seasonal variation of sea surface temperature, we investigated the evolution of thermal stratification below the summertime thin mixed layer (i.e. evolution of seasonal thermocline) and its vertical structure in the North Pacific using high vertical resolution temperature profile observed by Argo floats. We quantified the vertical structure of seasonal thermocline as deviations from the linear structure where the vertical gradient of temperature is constant, that is, "shape anomaly". The shape anomaly is variable representing the extent of the bend of temperature profiles. We found that there are larger values of shape anomaly in the region where the seasonal sea surface temperature warming is relatively faster. To understand the regional difference of shape anomalies, we investigated the relationship between time changes in shape anomalies and net surface heat flux and surface kinetic energy flux. From May to July, the analysis indicated that, in a large part of North Pacific, there's a tendency for shape anomalies to develop strongly (weakly) under the conditions of large (small) downward net surface heat flux and small (large) downward surface kinetic energy flux. Since weak (strong) development of shape anomalies means efficient (inefficient) downward heat transport from the surface, these results suggest that the regional difference of the downward heat penetration below mixed layer is explained reasonably well by differences in surface heat forcing and surface wind forcing in a vertical one dimensional framework. [1] Hosoda et al. (2015), J. Oceanogr., 71, 541-556.

Near-ground cooling efficacies of trees and high-albedo surfaces

Energy Technology Data Exchange (ETDEWEB)

Levinson, Ronnen Michael [Univ. of California, Berkeley, CA (United States)

1997-05-01

Daytime summer urban heat islands arise when the prevalence of dark-colored surfaces and lack of vegetation make a city warmer than neighboring countryside. Two frequentlyproposed summer heat island mitigation measures are to plant trees and to increase the albedo (solar reflectivity) of ground surfaces. This dissertation examines the effects of these measures on the surface temperature of an object near the ground, and on solar heating of air near the ground. Near-ground objects include people, vehicles, and buildings. The variation of the surface temperature of a near-ground object with ground albedo indicates that a rise in ground albedo will cool a near-ground object only if the object’s albedo exceeds a critical value. This critical value of object albedo depends on wind speed, object geometry, and the height of the atmospheric thermal boundary layer. It ranges from 0.15 to 0.37 for a person. If an object has typical albedo of 0.3, increasing the ground albedo by 0.25 perturbs the object’s surface temperature by -1 to +2 K. Comparing a tree’s canopy-to-air convection to the reduction in ground-to-air convection induced by tree shading of the ground indicates that the presence of a tree can either increase or decrease solar heating of ground-level air. The tree’s net effect depends on the extent to which solar heating of the canopy is dissipated by evaporation, and on the fraction of air heated by the canopy that flows downward and mixes with the ground-level air. A two-month lysimeter (plant-weighing) experiment was conducted to measure instantaneous rates of water loss from a tree under various conditions of weather and soil-moisture. Calculations of canopy-to-air convection and the reduction of ground-to-air convection based on this data indicate that canopy-induced heating would negate shadowinduced cooling if approximately 45% of the canopy-heated air mixed with ground level air. This critical fraction is comparable to typical downward mixing

Evaluation of Haney-Type Surface Thermal Boundary Conditions Using a Coupled Atmosphere and Ocean Model

National Research Council Canada - National Science Library

Chu, Peter C; Chen, Yuchun; Lu, Shihua

2001-01-01

... (Russell et al,, 1995) was used to verify the validity of Haney-type surface thermal boundary condition, which linearly connects net downward surface heat flux Q to air / sea temperature difference DeltaT by a relaxation coefficient K...

Experimental observation of pulsating instability under acoustic field in downward-propagating flames at large Lewis number

KAUST Repository

Yoon, Sung Hwan; Hu, Longhua; Fujita, Osamu

2017-01-01

by interaction between heat release and acoustic pressure fluctuations of the downward-propagating premixed flames in a tube to enhance conductive heat loss at the tube wall and radiative heat loss at the open end of the tube due to extended flame residence time

Comparison of vehicle-mounted forward-looking polarimetric infrared and downward-looking infrared sensors for landmine detection

NARCIS (Netherlands)

Cremer, F.; Schavemaker, J.G.M.; Jong, W. de; Schutte, K.

2003-01-01

This paper gives a comparison of two vehicle-mounted infrared systems for landmine detection. The first system is a down-ward looking standard infrared camera using processing methods developed within the EU project LOTUS. The second system is using a forward-looking polarimetric infrared camera.

RELAP5 analysis of subcooled boiling appearance and disappearance in downward flow

International Nuclear Information System (INIS)

Ristevski, R.; Parzer, I.; Spasojevic, D.

1999-01-01

The presented paper will mainly consider heat and mass transfer phenomenology in the subcooled boiling regime of downward liquid flow at low velocities. More specifically, it will focus on the effects of appearance and disappearance of two-phase flow at low liquid velocities, in the area where gravity force has significant influence. Two among a series of tests performed on a high-pressure circulation loop, installed in Vinca, will be analyzed. The experimental findings and theoretical consideration of these processes and phenomena will be compared with RELAP5/MOD3.2.2 predictions.(author)

A theoretical model of air and steam co-injection to prevent the downward migration of DNAPLs during steam-enhanced extraction

Science.gov (United States)

Kaslusky, Scott F.; Udell, Kent S.

2002-04-01

When steam is injected into soil containing a dense volatile non-aqueous phase liquid contaminant the DNAPL vaporized within the heated soil region condenses and accumulates ahead of the steam condensation front. If enough DNAPL accumulates, gravitational forces can overcome trapping forces allowing the liquid contaminant to flow downward. By injecting air with steam, a portion of the DNAPL vapor remains suspended in equilibrium with the air, decreasing liquid contaminant accumulation ahead of the steam condensation front, and thus reducing the possibility of downward migration. In this work, a one-dimensional theoretical model is developed to predict the injection ratio of air to steam that will prevent the accumulation of volatile DNAPLs. The contaminated region is modeled as a one-dimensional homogeneous porous medium with an initially uniform distribution of a single component contaminant. Mass and energy balances are combined to determine the injection ratio of air to steam that eliminates accumulation of the contaminant ahead of the steam condensation front, and hence reduces the possibility of downward migration. The minimum injection ratio that eliminates accumulation is defined as the optimum injection ratio. Example calculations are presented for three DNAPLs, carbon tetrachloride (CCl 4), trichloroethylene (TCE), and perchloroethylene (PCE). The optimum injection ratio of air to steam is shown to depend on the initial saturation and the volatility of the liquid contaminant. Numerical simulation results are presented to validate the model, and to illustrate downward migration for ratios less than optimum. Optimum injection ratios determined from numerical simulations are shown to be in good agreement with the theoretical model.

Vertical downward subcooled bubbly flow modelling with RELAP5/MOD3.2.2 gamma

International Nuclear Information System (INIS)

Ristevski, R.; Parzer, I.; Markov, Z.

2000-01-01

The presented paper will consider the correlation for void fraction distribution in the subcooled boiling flow regime of downward liquid flow at low velocities. More specifically, it will focus on the choice of the most appropriate heat and mass transfer correlation. The experimental findings and theoretical consideration of these processes and phenomena will be compared with RELAP5/MOD3.2.2 Gamma predictions. (author)

Tornado frequency in the USA - meteorological and non-meteorological factors of a downward trend

Directory of Open Access Journals (Sweden)

Mihajlović Jovan

2015-01-01

Full Text Available Citing numerical simulations, climate alarmists believe that global warming will lead to more frequent and more intensive tornadoes. Considering temperature increase data in the contiguous USA, this study has investigated the trend of strong tornadoes in F3+ category in the 1954-2012 period. Statistically significant decrease of tornadoes per year at an average rate of 0.44 has been recorded, that is, 4.4 tornadoes per decade. Tornado increase has been recorded with F0 and F1 categories and the cause of this increase lies in meteorological and non-meteorological factors. By using upper and lower standard deviation values, the stages of tornado activity have been singled out. The 1957-1974 period may be considered as an active stage and the 1978-2009 period as an inactive stage. Upward trend of air temperature increase does not correspond with the downward trend of the number of F3+ tornado category, while the correlation coefficient between these two variables is R = −0.14. This fact does not correspond with the simulation results and output data of various numerical models anticipating an increase in the number and intensity of tornado events in the conditions of surface air temperature growth.

Feeling bad, but satisfied : the effects of upward and downward comparison upon mood and marital satisfaction

NARCIS (Netherlands)

Buunk, B.P.; Ybema, J.F.

2003-01-01

In a sample of 135 women from rural areas, the effects of social comparison with the marriage of another woman upon mood, identification and relationship evaluation were examined. Upward targets evoked a more positive mood, and a less negative mood than downward targets, while, in contrast, the

Estimating spatially distributed monthly evapotranspiration rates by linear transformations of MODIS daytime land surface temperature data

Directory of Open Access Journals (Sweden)

J. Szilagyi

2009-05-01

Full Text Available Under simplifying conditions catchment-scale vapor pressure at the drying land surface can be calculated as a function of its watershed-representative temperature (<T_s> by the wet-surface equation (WSE, similar to the wet-bulb equation in meteorology for calculating the dry-bulb thermometer vapor pressure of the Complementary Relationship of evaporation. The corresponding watershed ET rate, , is obtained from the Bowen ratio with the help of air temperature, humidity and percent possible sunshine data. The resulting (<T_s>, pair together with the wet-environment surface temperature (<T_ws> and ET rate (ET_w, obtained by the Priestley-Taylor equation, define a linear transformation on a monthly basis by which spatially distributed ET rates can be estimated as a sole function of MODIS daytime land surface temperature, T_s, values within the watershed. The linear transformation preserves the mean which is highly desirable. <T_ws>, in the lack of significant open water surfaces within the study watershed (Elkhorn, Nebraska, was obtained as the mean of the smallest MODIS T_s values each month. The resulting period-averaged (2000–2007 catchment-scale ET rate of 624 mm/yr is very close to the water-balance derived ET rate of about 617 mm/yr. The latter is a somewhat uncertain value due to the effects of (a observed groundwater depletion of about 1m over the study period caused by extensive irrigation, and; (b the uncertain rate of net regional groundwater supply toward the watershed. The spatially distributed ET rates correspond well with soil/aquifer properties and the resulting land use type (i.e. rangeland versus center-pivot irrigated crops.

Downward Causation and the Neurobiology of Free Will

CERN Document Server

Murphy, Nancey; O’Connor, Timothy

2009-01-01

How is free will possible in the light of the physical and chemical underpinnings of brain activity and recent neurobiological experiments? How can the emergence of complexity in hierarchical systems such as the brain, based at the lower levels in physical interactions, lead to something like genuine free will? The nature of our understanding of free will in the light of present-day neuroscience is becoming increasingly important because of remarkable discoveries on the topic being made by neuroscientists at the present time, on the one hand, and its crucial importance for the way we view ourselves as human beings, on the other. A key tool in understanding how free will may arise in this context is the idea of downward causation in complex systems, happening coterminously with bottom up causation, to form an integral whole. Top-down causation is usually neglected, and is therefore emphasized in the other part of the book’s title. The concept is explored in depth, as are the ethical and legal implications of...

Predicting Downward Longwave Radiation for Various Land Use in All-Sky Condition: Northeast Florida

Directory of Open Access Journals (Sweden)

Chi-Han Cheng

2014-01-01

Full Text Available Accurate estimate of the surface longwave radiation is important for the surface radiation budget, which in turn controls evaporation and sensible heat fluxes. Regional land use changes can impact local weather conditions; for example, heterogeneous land use patterns and temporal changes in atmospheric circulation patterns would affect air temperature and water vapor pressure, which are more commonly used as inputs in existing models for estimating downward longwave radiation (LWd. In this study, first, we analyzed the cloud cover and land use covers impacts on LWd. Next, LWd on all-sky conditions were developed by using the existing land use-adapted model and cloud cover data from the region of Saint Johns River Water Management District (SJRWMD, FL. The results show that factors, such as, seasonal effects, cloud cover, and land use, are of importance in the estimation of LWd and they cannot be ignored when developing a model for LWd prediction. The all-sky land use-adapted model with all factors taken into account performs better than other existing models statistically. The results of the statistical analyses indicated that the BIAS, RMSE, MAE, and PMRE are −0.18 Wm−2, 10.81 Wm−2, 8.00 Wm−2, and 2.30%; −2.61 Wm−2, 14.45 Wm−2, 10.64 Wm−2, and 3.19%; −0.07 Wm−2, 10.53 Wm−2, 8.03 Wm−2, and 2.27%; and −0.62 Wm−2, 13.97 Wm−2, 9.76 Wm−2, and 2.87% for urban, rangeland, agricultural, and wetland areas, respectively.

Doing worse, but feeling happy : Social comparison and identification in response to upward and downward targets

NARCIS (Netherlands)

Groothof, H.; Siero, F.W.; Buunk, Abraham (Bram)

2007-01-01

We investigated people's responses to exposure to downward and upward targets. In Study 1, among 197 participants, it was predicted and found that such exposure led to a contrast effect on self-evaluation, and to an assimilation effect on affect. In Study 2, among 148 participants, it was predicted

SUNYA Regional Climate Model Simulations of East Asia Summer Monsoon: Effects of Cloud Vertical Structure on the Surface Energy Balance

Directory of Open Access Journals (Sweden)

Wei Gong and Wei-Chyung Wang

2007-01-01

Full Text Available We used the State University of New York at Albany (SUNYA regional climate model to study the effect of cloud vertical distribution in affecting the surface energy balance of the East Asia summer monsoon (EASM. Simulations were conducted for the summers of 1988 and 1989, during which large contrast in the intra-seasonal cloud radiative forcing (CRF was observed at the top of the atmosphere. The model results indicate that both the high and low clouds are persistent throughout the summer months in both years. Because of large cloud water, low clouds significantly reduce the solar radiation flux reaching the surface, which nevertheless still dominate the surface energy balance, accounting for more than 50% of the surface heating. The low clouds also contribute significantly the downward longwave radiation to the surface with values strongly dependent on the cloud base temperature. The presence of low clouds effectively decreases the temperature and moisture gradients near surface, resulting in a substantial decrease in the sensible and latent heat fluxes from surface, which partially compensate the decrease of the net radiative cooling of the surface. For example, in the two days, May 8 and July 11 of 1988, the total cloud cover of 80% is simulated, but the respective low cloud cover (water was 63% (114 gm-2 and 22% (21 gm-2. As a result, the downward solar radiation is smaller by 161 Wm-2 in May 8. On the other hand, the cloud temperature was _ lower, yielding 56 Wm-2 smaller downward longwave radiation. The near surface temperature and gradient is more than _ smaller (and moisture gradient, leading to 21 and 81 Wm-2 smaller sensible heat and latent heat fluxes. It is also demonstrated that the model is capable to reproduce the intraseasonal variation of shortwave CRF, and catches the relationship between total cloud cover and SW CRF. The model results show the dominance of high cloud on the regional mean longwave CRF and low cloud on the intra

Extracting Leaf Area Index by Sunlit Foliage Component from Downward-Looking Digital Photography under Clear-Sky Conditions

Directory of Open Access Journals (Sweden)

Yelu Zeng

2015-10-01

Full Text Available The development of near-surface remote sensing requires the accurate extraction of leaf area index (LAI from networked digital cameras under all illumination conditions. The widely used directional gap fraction model is more suitable for overcast conditions due to the difficulty to discriminate the shaded foliage from the shadowed parts of images acquired on sunny days. In this study, a new LAI extraction method by the sunlit foliage component from downward-looking digital photography under clear-sky conditions is proposed. In this method, the sunlit foliage component was extracted by an automated image classification algorithm named LAB2, the clumping index was estimated by a path length distribution-based method, the LAD and G function were quantified by leveled digital images and, eventually, the LAI was obtained by introducing a geometric-optical (GO model which can quantify the sunlit foliage proportion. The proposed method was evaluated at the YJP site, Canada, by the 3D realistic structural scene constructed based on the field measurements. Results suggest that the LAB2 algorithm makes it possible for the automated image processing and the accurate sunlit foliage extraction with the minimum overall accuracy of 91.4%. The widely-used finite-length method tends to underestimate the clumping index, while the path length distribution-based method can reduce the relative error (RE from 7.8% to 6.6%. Using the directional gap fraction model under sunny conditions can lead to an underestimation of LAI by (1.61; 55.9%, which was significantly outside the accuracy requirement (0.5; 20% by the Global Climate Observation System (GCOS. The proposed LAI extraction method has an RMSE of 0.35 and an RE of 11.4% under sunny conditions, which can meet the accuracy requirement of the GCOS. This method relaxes the required diffuse illumination conditions for the digital photography, and can be applied to extract LAI from downward-looking webcam images

Experimental study on interfacial area transport in downward two-phase flow

Science.gov (United States)

Wang, Guanyi

In view of the importance of two group interfacial area transport equations and lack of corresponding accurate downward flow database that can reveal two group interfacial area transport, a systematic database for adiabatic, air-water, vertically downward two-phase flow in a round pipe with inner diameter of 25.4 mm was collected to gain an insight of interfacial structure and provide benchmarking data for two-group interfacial area transport models. A four-sensor conductivity probe was used to measure the local two phase flow parameters and data was collected with data sampling frequency much higher than conventional data sampling frequency to ensure the accuracy. Axial development of local flow parameter profiles including void fraction, interfacial area concentration, and Sauter mean diameter were presented. Drastic inter-group transfer of void fraction and interfacial area was observed at bubbly to slug transition flow. And the wall peaked interfacial area concentration profiles were observed in churn-turbulent flow. The importance of local data about these phenomenon on flow structure prediction and interfacial area transport equation benchmark was analyzed. Bedsides, in order to investigate the effect of inlet conditions, all experiments were repeated after installing the flow straightening facility, and the results were briefly analyzed. In order to check the accuracy of current data, the experiment results were cross-checked with rotameter measurement as well as drift-flux model prediction, the averaged error is less than 15%. Current models for two-group interfacial area transport equation were evaluated using these data. The results show that two-group interfacial area transport equations with current models can predict most flow conditions with error less than 20%, except some bubbly to slug transition flow conditions and some churn-turbulent flow conditions. The disagreement between models and experiments could result from underestimate of inter

Empirical models of monthly and annual surface albedo in managed boreal forests of Norway

Science.gov (United States)

Bright, Ryan M.; Astrup, Rasmus; Strømman, Anders H.

2013-04-01

As forest management activities play an increasingly important role in climate change mitigation strategies of Nordic regions such as Norway, Sweden, and Finland -- the need for a more comprehensive understanding of the types and magnitude of biogeophysical climate effects and their various tradeoffs with the global carbon cycle becomes essential to avoid implementation of sub-optimal policy. Forest harvest in these regions reduces the albedo "masking effect" and impacts Earth's radiation budget in opposing ways to that of concomitant carbon cycle perturbations; thus, policies based solely on biogeochemical considerations in these regions risk being counterproductive. There is therefore a need to better understand how human disturbances (i.e., forest management activities) affect important biophysical factors like surface albedo. An 11-year remotely sensed surface albedo dataset coupled with stand-level forest management data for a variety of stands in Norway's most productive logging region are used to develop regression models describing temporal changes in monthly and annual forest albedo following clear-cut harvest disturbance events. Datasets are grouped by dominant tree species and site indices (productivity), and two alternate multiple regression models are developed and tested following a potential plus modifier approach. This resulted in an annual albedo model with statistically significant parameters that explains a large proportion of the observed variation, requiring as few as two predictor variables: i) average stand age - a canopy modifier predictor of albedo, and ii) stand elevation - a local climate predictor of a forest's potential albedo. The same model structure is used to derive monthly albedo models, with models for winter months generally found superior to summer models, and conifer models generally outperforming deciduous. We demonstrate how these statistical models can be applied to routine forest inventory data to predict the albedo

Sky glint correction in measurements of upward radiance above the sea surface

Directory of Open Access Journals (Sweden)

Jerzy Olszewski

2000-06-01

Full Text Available An experiment has been performed to determine the upward water-leaving radiance by non-contact measurement of the total upward and downward radiance above the sea surface from a moving ship. The method for achieving this aim is described: the radiance meters are both tilted in such a way that the upward radiance meter can 'see' that part of the measured downward radiance which would be reflected if the water surface were smooth and which is not derived directly from solar glitter. Both meters are firmly fixed in a special frame, which ensures that the required orientation is the most probable one. Time records of the measured parameters are analysed. The results are presented in several forms: frequency (histogram analysis appears to be the most promising one.

Sedimentation and fouling of optical surfaces at the ANTARES site

Science.gov (United States)

ANTARES Collaboration; CAU CEFREM Collaboration; Amram, P.; Anghinolfi, M.; Anvar, S.; Ardellier-Desages, F. E.; Aslanides, E.; Aubert, J.-J.; Azoulay, R.; Bailey, D.; Basa, S.; Battaglieri, M.; Bellotti, R.; Beltramelli, J.; Benhammou, Y.; Berthier, R.; Bertin, V.; Billault, M.; Blaes, R.; Bland, R. W.; Blondeau, F.; de Botton, N.; Boulesteix, J.; Brooks, C. B.; Brunner, J.; Cafagna, F.; Calzas, A.; Capone, A.; Caponetto, L.; Cârloganu, C.; Carmona, E.; Carr, J.; Cartwright, S. L.; Cecchini, S.; Ciacio, F.; Circella, M.; Compère, C.; Cooper, S.; Coyle, P.; Cuneo, S.; Danilov, M.; van Dantzig, R.; de Marzo, C.; Destelle, J.-J.; de Vita, R.; Dispau, G.; Druillole, F.; Engelen, J.; Feinstein, F.; Ferdi, C.; Festy, D.; Fopma, J.; Gallone, J.-M.; Giacomelli, G.; Goret, P.; Gournay, J.-F.; Hallewell, G.; Heijboer, A.; Hernández-Rey, J. J.; Hubbard, J. R.; Jaquet, M.; de Jong, M.; Karolak, M.; Keller, P.; Kooijman, P.; Kouchner, A.; Kudryavtsev, V. A.; Lafoux, H.; Lagier, P.; Lamare, P.; Languillat, J.-C.; Laubier, L.; Laugier, J.-P.; Leilde, B.; Le Provost, H.; Le van Suu, A.; Lo Nigro, L.; Lo Presti, D.; Loucatos, S.; Louis, F.; Lyashuk, V.; Magnier, P.; Marcelin, M.; Margiotta, A.; Masullo, R.; Mazéas, F.; Mazeau, B.; Mazure, A.; McMillan, J. E.; Migneco, E.; Millot, C.; Mols, P.; Montanet, F.; Montaruli, T.; Moscoso, L.; Musumeci, M.; Nezri, E.; Nooren, G. J.; Oberski, J. E. J.; Olivetto, C.; Oppelt-Pohl, A.; Palanque-Delabrouille, N.; Papaleo, R.; Payre, P.; Perrin, P.; Petruccetti, M.; Petta, C.; Piattelli, P.; Poinsignon, J.; Potheau, R.; Queinec, Y.; Racca, C.; Raia, G.; Randazzo, N.; Rethore, F.; Riccobene, G.; Ricol, J.-S.; Ripani, M.; Roca-Blay, V.; Romeyer, A.; Rostovstev, A.; Russo, G. V.; Sacquin, Y.; Salusti, E.; Schuller, J.-P.; Schuster, W.; Soirat, J.-P.; Souvorova, O.; Spooner, N. J. C.; Spurio, M.; Stolarczyk, T.; Stubert, D.; Taiuti, M.; Tao, C.; Thompson, L. F.; Tilav, S.; Triay, R.; Usik, A.; Valdy, P.; Valente, V.; Varlamov, I.; Vaudaine, G.; Vernin, P.; Vladimirsky, E.; Vorobiev, M.; de Witt Huberts, P.; de Wolf, E.; Zakharov, V.; Zavatarelli, S.; Zornoza, Juan de Dios; Zún~Iga, J.; Aloïsi, J.-C.; Kerhervé, Ph.; Monaco, A.

2003-05-01

ANTARES is a project leading towards the construction and deployment of a neutrino telescope in the deep Mediterranean Sea. The telescope will use an array of photomultiplier tubes to detect the Cherenkov light emitted by muons resulting from the interaction with matter of high energy neutrinos. In the vicinity of the deployment site the ANTARES Collaboration has performed a series of in situ measurements to study the change in light transmission through glass surfaces during immersions of several months. The average loss of light transmission is estimated to be only ~2% at the equator of a glass sphere one year after deployment. It decreases with increasing zenith angle, and tends to saturate with time. The transmission loss, therefore, is expected to remain small for the several year lifetime of the ANTARES detector whose optical modules are oriented downwards. The measurements were complemented by the analysis of the 210Pb activity profile in sediment cores and the study of biofouling on glass plates. Despite a significant sedimentation rate at the site, in the 0.02-0.05 cmyr-1 range, the sediments adhere loosely to the glass surfaces and can be washed off by water currents. Further, fouling by deposits of light-absorbing particulates is only significant for surfaces facing upwards.

An evaluation of the 18- and 12-month basic postgraduate training programmes in Denmark

DEFF Research Database (Denmark)

Kjaer, Niels Kristian; Qvesel, Dorte; Kodal, Troels

2010-01-01

equipped and less ready for continued specialisation than doctors of the 18-month programme and they requested a downward adjustment of the learning objectives associated with the educational positions which follow their basic training. Physicians do not expect the increased focus on learning...... and new programmes evaluate their training, and it explores their attitudes towards the new postgraduate training programme. MATERIAL AND METHODS: We developed a questionnaire by which quantitative and qualitative data were collected. The questionnaire was sent to all physicians following basic...... and supervision to compensate for the six-month reduction of the training period. Internal medicine should be included in the basic postgraduate training of all physicians. Training in secondary as well as primary health care was requested. CONCLUSION: The young physicians were reluctant towards the new basic...

Fixing the Phillips curve: The case of downward nominal wage rigidity in the US

OpenAIRE

Reitz, Stefan; Slopek, Ulf D.

2012-01-01

Whereas microeconomic studies point to pronounced downward rigidity of nominal wages in the US economy, the standard Phillips curve neglects such a feature. Using a stochastic frontier model we find macroeconomic evidence of a strictly nonnegative error in an otherwise standard Phillips curve in post-war data on the US nonfinancial corporate sector. This error depends on growth in the profit ratio, output, and trend productivity, which should all determine the flexibility of wage adjustments....

Visual function after implantation of single-piece toric hydrophilic acrylic intraocular lenses with hydrophobic surface six months after cataract surgery

Directory of Open Access Journals (Sweden)

Alja Črnej

2012-06-01

Conclusion: Patients with medium to high corneal astigmatism and implanted single-piece toric hydrophilic acrylic IOLs with hydrophobic surface have very good visual function six months postoperatively.

Impacts of Saharan dust on downward irradiance and photosynthetically available radiation in the water column

Directory of Open Access Journals (Sweden)

T. Ohde

2012-09-01

Full Text Available A semi-empirical approach was used to quantify the modification of the underwater light field in amplitude (magnitude effect and spectral distribution (spectral effect by different atmospheric conditions altering the incident light. The approach based on an optical model in connection with radiation measurements in the area off Northwest Africa. Key inputs of the model were parameterized magnitude and spectral effects. Various atmospheric conditions were considered: clear sky, dusty sky without clouds, cloudy sky without dust and skies with different ratios of dust and clouds. Their impacts were investigated concerning the modification of the downward irradiance and photosynthetically available radiation in the water column. The impact on downward irradiance depended on the wavelength, the water depth, the optical water properties, the dust and cloud properties, and the ratio of clouds to dust. The influence of clouds on the amplitude can be much higher than that of dust. Saharan dust reduced the photosynthetically available radiation in the water column. Ocean regions were more influenced than coastal areas. Compensations of the magnitude and spectral effects were observed at special water depths in ocean regions and at atmospheric conditions with definite cloud to dust ratios.

An Improved Method For Retrieving Land Surface Albedo Over Rugged Terrain

NARCIS (Netherlands)

Gao, B.; Jia, L.; Menenti, M.

2014-01-01

Land surface albedo is a very important parameter, which can be derived from a bidirectional reflectance distribution function (BRDF) model with angular integration of BRDF in a particular distribution of downward solar irradiance. The Algorithm for MODIS Bidirectional Reflectance Anisotropic of

The effect of surface anisotropy in the slippery zone of Nepenthes alata pitchers on beetle attachment

Directory of Open Access Journals (Sweden)

Elena V. Gorb

2011-06-01

Full Text Available The slippery zone in pitchers of the carnivorous plant Nepenthes alata bears scattered prominent lunate cells and displays continuous epicuticular crystalline wax coverage. The aim of this study was to examine the influence of the surface anisotropy, caused by the shape of lunate cells, on insect attachment ability. Traction tests with ladybird beetles Coccinella septempunctata were performed in two types of experiments, where surface samples of (1 intact pitchers, (2 chemically de-waxed pitchers, and (3 their polymer replicas were placed horizontally. Beetle traction forces were measured when they walked on test surfaces in either an upward (towards the peristome or downward (towards the pitcher bottom direction, corresponding to the upright or inverted positions of the pitcher. On intact pitcher surfaces covered with both lunate cells and wax crystals, experiments showed significantly higher forces in the direction towards the pitcher bottom. To distinguish between the contributions, from claw interlocking and pad adhesion, to insect attachment on the pitcher surfaces, intact versus claw-ablated beetles were used in the second type of experiment. On both de-waxed plant samples and their replicas, intact insects generated much higher forces in the downward direction compared to the upward one, whereas clawless insects did not. These results led to the conclusion that, (i due to the particular shape of lunate cells, the pitcher surface has anisotropic properties in terms of insect attachment, and (ii claws were mainly responsible for attachment enhancement in the downward pitcher direction, since, in this direction, they could interlock with overhanging edges of lunate cells.

Experimental study of natural convection heat transfer from an isothermal combined geometry (downward cone- cylinder)

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, A. [Yazd Univ., Yazd (Iran, Islamic Republic of). Dept. of Mechanical Engineering; Goharkhah, M.; Ashjaee, M. [Tehran Univ., Tehran (Iran, Islamic Republic of). Dept. of Mechanical Engineering

2009-07-01

Laminar free convection heat transfer from an isothermal combined geometry which consists of a downward cone attached to a vertical cylinder was studied. In particular, a Mach-Zehnder interferometer was used to determine the change in local and average heat transfer coefficients on the surface of an isothermal combined geometry for different vertex angles. The effect of the vertex angle on heat transfer was also investigated by keeping the height of the cylinder and slant length of the cone constant for all objects. The experimental data showed that the local heat transfer coefficient on the conical part increased in the vicinity of the cylinder and cone intersection. The distance between the point of minimum heat transfer coefficient on the cone and vertex of the cone decreased as the vertex angle increased. The maximum average Nusselt number for a constant Rayleigh number was obtained for the geometry with the smallest vertex angle. For all objects, the average Nusselt number increased with an increase in the Rayleigh number. An experiment was carried out on a vertical isothermal cylinder of circular cross section in order to validate the experimental approach. An analytical solution was found to be in good agreement with experimental results. 31 refs., 9 figs.

Oceanographic Monthly Summary

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Monthly Summary contains sea surface temperature (SST) analyses on both regional and ocean basin scales for the Atlantic, Pacific, and Indian Oceans....

Tropospheric weather influenced by solar wind through atmospheric vertical coupling downward control

Science.gov (United States)

Prikryl, Paul; Bruntz, Robert; Tsukijihara, Takumi; Iwao, Koki; Muldrew, Donald B.; Rušin, Vojto; Rybanský, Milan; Turňa, Maroš; Šťastný, Pavel

2018-06-01

Occurrence of severe weather in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system is investigated. It is observed that significant snowfall, wind and heavy rain, particularly if caused by low pressure systems in winter, tend to follow arrivals of high-speed solar wind. Previously published statistical evidence that explosive extratropical cyclones in the northern hemisphere tend to occur within a few days after arrivals of high-speed solar wind streams from coronal holes (Prikryl et al., 2009, 2016) is corroborated for the southern hemisphere. Cases of severe weather events are examined in the context of the magnetosphere-ionosphere-atmosphere (MIA) coupling. Physical mechanism to explain these observations is proposed. The leading edge of high-speed solar wind streams is a locus of large-amplitude magneto-hydrodynamic waves that modulate Joule heating and/or Lorentz forcing of the high-latitude lower thermosphere generating medium-scale atmospheric gravity waves that propagate upward and downward through the atmosphere. Simulations of gravity wave propagation in a model atmosphere using the Transfer Function Model (Mayr et al., 1990) reveal that propagating waves originating in the lower thermosphere can excite a spectrum of gravity waves in the lower atmosphere. In spite of significantly reduced amplitudes but subject to amplification upon reflection in the upper troposphere, these gravity waves can provide a lift of unstable air to release instabilities in the troposphere and initiate convection to form cloud/precipitation bands. It is primarily the energy provided by release of latent heat that leads to intensification of storms. These results indicate that vertical coupling in the atmosphere exerts downward control from solar wind to the lower atmospheric levels influencing tropospheric weather development.

Measurements of the eigenfunction of reversed shear Alfvén eigenmodes that sweep downward in frequency

International Nuclear Information System (INIS)

Heidbrink, W. W.; Austin, M. E.; Spong, D. A.; Tobias, B. J.; Van Zeeland, M. A.

2013-01-01

Reversed shear Alfvén eigenmodes (RSAEs) usually sweep upward in frequency when the minimum value of the safety factor q min decreases in time. On rare occasions, RSAEs sweep downward prior to the upward sweep. Electron cyclotron emission measurements show that the radial eigenfunction during the downsweeping phase is similar to the eigenfunction of normal, upsweeping RSAEs

Mixed convection heat transfer to carbon dioxide flowing upward and downward in a vertical tube and an annular channel

International Nuclear Information System (INIS)

Bae, Yoon Y.

2011-01-01

Highlights: → Experimental results of heat transfer at a supercritical pressure for a tube with an inner diameter of 4.57 mm and a corresponding annular channel (8 mm x 10 mm, 1 mm gap) were compared each other. → Effect of various parameters such as pressure, flow direction, diameter, channel shape, was investigated. → Existing correlation for supercritical heat transfer were evaluated against the experimental data. → Some unusual characteristics of supercritical heat transfer, such as overshoot and non-monotonic behavior against buoyancy parameter, were discussed. → New correlations were proposed based on the experimental data. - Abstract: This paper addresses three main subjects in supercritical heat transfer: (1) difference in thermal characteristics between upward and downward flows; (2) effect of simulating flow channel shape; (3) evaluation of the existing supercritical heat transfer correlations. To achieve the objectives, a series of experiments was carried out with CO 2 flowing upward and downward in a circular tube with an inner diameter of 4.57 mm and an annular channel created between a tube with an inner diameter of 10 mm and a heater rod with an outer diameter of 8 mm. The working fluid, CO 2 , has been regarded as an appropriate modeling fluid for water, primarily because of their similarity in property variations against reduced temperatures. The mass flux ranged from 400 to 1200 kg/m 2 s. The heat flux was varied between 30 and 140 kW/m 2 so that the pseudo-critical point was located in the middle of the heated section at a given mass flux. The measurements were made at a pressure of 8.12 MPa, which corresponds to 110% of the critical pressure of CO 2 . The difference between the upward and downward flows was observed clearly. The heat transfer deterioration was observed in the downward flow through an annular subchannel over the region beyond the critical point. Several well-known correlations were evaluated against the experimental

Flow regime visualization and pressure drops of HFO-1234yf, R-134a and R-410A during downward two-phase flow in vertical return bends

International Nuclear Information System (INIS)

Padilla, Miguel; Revellin, Rémi; Wallet, Jérémy; Bonjour, Jocelyn

2013-01-01

Highlights: ► Visual observation of two-phase flow regimes during downward flow in a return bend. ► Bubble and vapor slug dynamical behaviors in downward slug flow are reported. ► Perturbation lengths up- and downstream of the return bend have been investigated. ► Measurement of 285 pressure drop data points for HFO-1234yf, R-134a and R-410A. -- Abstract: This paper provides a qualitative visual observation of the two-phase flow patterns for HFO-1234yf and R-134a during downward flow in a vertical 6.7 mm inner diameter glass return bend. The different flow regimes observed are: slug, intermittent and annular flows. Bubble and vapor slug dynamical behaviors in downward slug flow are reported for HFO-1234yf. In addition, to determine the perturbation lengths up- and downstream of the return bend, the total pressure drop has been measured at different pressure tap location up- and downstream of the singularity. Furthermore, 285 pressure drop data points measured for two-phase flow of HFO-1234yf, R-134a and R-410A in vertical downward flow return bends are presented. The flow behavior in the return bend, which is subjected to the complex combined actions of gravity and centrifugal force was expressed in terms of the vapor Froude number. This experimental pressure drop database, which is included in the appendix, is compared to four well-known prediction methods available in the literature

The Downward Causality and the Hard Problem of Consciousness or Why Computer Programs Do not Work in the Dark

Directory of Open Access Journals (Sweden)

Boldachev Alexander

2015-01-01

Full Text Available Any low-level processes, the sequence of chemical interactions in a living cell, muscle cellular activity, processor commands or neuron interaction, is possible only if there is a downward causality, only due to uniting and controlling power of the highest level. Therefore, there is no special “hard problem of consciousness”, i.e. the problem of relation of ostensibly purely biological materiality and non-causal mentality - we have only the single philosophical problem of relation between the upward and downward causalities, the problem of interrelation between hierarchic levels of existence. It is necessary to conclude that the problem of determinacy of chemical processes by the biological ones and the problem of neuron interactions caused by consciousness are of one nature and must have one solution.

Improvements of top-of-atmosphere and surface irradiance computations with CALIPSO-, CloudSat-, and MODIS-derived cloud and aerosol properties

Science.gov (United States)

Kato, Seiji; Rose, Fred G.; Sun-Mack, Sunny; Miller, Walter F.; Chen, Yan; Rutan, David A.; Stephens, Graeme L.; Loeb, Norman G.; Minnis, Patrick; Wielicki, Bruce A.; Winker, David M.; Charlock, Thomas P.; Stackhouse, Paul W., Jr.; Xu, Kuan-Man; Collins, William D.

2011-10-01

One year of instantaneous top-of-atmosphere (TOA) and surface shortwave and longwave irradiances are computed using cloud and aerosol properties derived from instruments on the A-Train Constellation: the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, the CloudSat Cloud Profiling Radar (CPR), and the Aqua Moderate Resolution Imaging Spectrometer (MODIS). When modeled irradiances are compared with those computed with cloud properties derived from MODIS radiances by a Clouds and the Earth's Radiant Energy System (CERES) cloud algorithm, the global and annual mean of modeled instantaneous TOA irradiances decreases by 12.5 W m-2 (5.0%) for reflected shortwave and 2.5 W m-2 (1.1%) for longwave irradiances. As a result, the global annual mean of instantaneous TOA irradiances agrees better with CERES-derived irradiances to within 0.5W m-2 (out of 237.8 W m-2) for reflected shortwave and 2.6W m-2 (out of 240.1 W m-2) for longwave irradiances. In addition, the global annual mean of instantaneous surface downward longwave irradiances increases by 3.6 W m-2 (1.0%) when CALIOP- and CPR-derived cloud properties are used. The global annual mean of instantaneous surface downward shortwave irradiances also increases by 8.6 W m-2 (1.6%), indicating that the net surface irradiance increases when CALIOP- and CPR-derived cloud properties are used. Increasing the surface downward longwave irradiance is caused by larger cloud fractions (the global annual mean by 0.11, 0.04 excluding clouds with optical thickness less than 0.3) and lower cloud base heights (the global annual mean by 1.6 km). The increase of the surface downward longwave irradiance in the Arctic exceeds 10 W m-2 (˜4%) in winter because CALIOP and CPR detect more clouds in comparison with the cloud detection by the CERES cloud algorithm during polar night. The global annual mean surface downward longwave irradiance of

Dry Deposition, Surface Production and Dynamics of Aerosols in the Marine Boundary Layer

DEFF Research Database (Denmark)

Fairall, C.W.; Larsen, Søren Ejling

1984-01-01

A model of downward aerosol panicle flux characterized by dry deposition velocity, Vd, due to Slinn and Slinn (1980) is generalized to the case of nonzero surface concentration (absorbing surface with a surface source). A more general expression for the flux at some reference height is developed ...... produced as droplets at the surface and ‘continental’ background aerosols brought into the boundary layer at the top by entrainment and gravitational settling. Estimates of Si are provided....

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

are sufficiently below freezing, the near-surface environment is generally stably stratified and the hourly averaged turbulent fluxes are quite small and irregular with on average small downward sensible heat fluxes and upward latent heat and carbon dioxide fluxes. The magnitude of the turbulent fluxes increases rapidly when surface snow disappears and the air temperatures rise above freezing during spring melt and eventually reaches a summer maximum. Throughout the summer months strong upward sensible and latent heat fluxes and downward carbon dioxide (uptake by the surface) are typically observed indicating persistent unstable (convective) stratification. Due to the combined effects of day length and solar zenith angle, the convective boundary layer forms in the High Arctic (e.g., in Eureka) and can reach long-lived quasi-stationary states in summer. During late summer and early autumn all turbulent fluxes rapidly decrease in magnitude when the air temperature decreases and falls below freezing. Unlike Eureka, a pronounced zero-curtain effect consisting of a sustained surface temperature hiatus at the freezing point is observed in Tiksi during fall due to wetter and/or water saturated soils.

How Robust Are the Surface Temperature Fingerprints of the Atlantic Overturning Meridional Circulation on Monthly Time Scales?

Science.gov (United States)

Alexander-Turner, R.; Ortega, P.; Robson, J. I.

2018-04-01

It has been suggested that changes in the Atlantic Meridional Overturning Circulation (AMOC) can drive sea surface temperature (SST) on monthly time scales (Duchez et al., 2016, https://doi.org/10.1002/2017GB005667). However, with only 11 years of continuous observations, the validity of this result over longer, or different, time periods is uncertain. In this study, we use a 120 yearlong control simulation from a high-resolution climate model to test the robustness of the AMOC fingerprints. The model reproduces the observed AMOC seasonal cycle and its variability, and the observed 5-month lagged AMOC-SST fingerprints derived from 11 years of data. However, the AMOC-SST fingerprints are very sensitive to the particular time period considered. In particular, both the Florida current and the upper mid-ocean transport produce highly inconsistent fingerprints when using time periods shorter than 30 years. Therefore, several decades of RAPID observations will be necessary to determine the real impact of the AMOC on SSTs at monthly time scales.

Simulations of monthly mean nitrate concentrations in precipitation over East Asia

International Nuclear Information System (INIS)

Junling An; Xinjin Cheng; Ueda, Hiromasa; Kajino, Mizuo

2002-01-01

Monthly mean nitrate concentrations in precipitation over East Asia (10-55 o N, 75-155 o E) in April, July, September, and December of 1999 were simulated by using a regional air quality Eulerian model (RAQM) with meteorological fields four times per day taken from National Centers for Environmental Prediction. The distribution of the nitrate concentration in precipitation depends significantly on the emission patterns of nitrogen oxides (NO x =NO+NO 2 ) and volatile organic compound (VOC) and seasonal precipitation variability. The downward trend is also revealed, particularly on July and December. Highest concentrations are found in the industrialized regions, i.e., the coastal area of the Mainland of China, the Bay of the Huanghai Sea and the Bohai Sea, Korea, and Southern Japan. Long-range transport may cause elevated concentrations in remote areas downwind of the industrialized regions under favorable meteorological conditions, e.g., low precipitation. Comparison of observation and simulations indicates that the RAQM model reasonably predicts synoptic-scale changes in different months (seasons) and simulated nitrate levels in 4 months fit observed data with the discrepancy within a factor of 2. Exclusion of liquid chemistry within clouds is feasible for regional (1 o x1 o ) and long-term (monthly) nitrate simulations. The uncertainty originates mainly from that of the emission data and modeled precipitation amounts and initial and boundary conditions. (author)

Downwards Vertical Attention Bias in Conversion Disorder vs Controls: A Pilot Study.

Science.gov (United States)

Gazit, Sivan; Elkana, Odelia; Dawidowicz, Liraz; Yeshayahu, Liel; Biran, Iftah

Conversion disorder (CD) is a largely enigmatic disorder, one that requires a thorough ruling-out process. Prior research suggests that metaphors and conceptualization are rooted in physical experience, and that we interpret our affective world through metaphors. Spatial metaphors (interaction of affect and vertical space) are a prominent example of the grounding of metaphors. This is a relatively unpaved direction of research of CD. The present pilot study sought to explore this view by investigating the "healthy is up, sick is down" spatial metaphors (e.g., "fell ill" and "top shape") in patients with CD, examining the correlation between the processing of bodily-related words, CD, and vertical space. We hypothesized that patients with CD, who experience their bodies as ill, will demonstrate a downwards bias when processing bodily-related words; corresponding to the "healthy is up, sick is down" spatial metaphor. A total of 8 female patients (ages M-38.13 SD-10.44) and 42 female controls (ages M-36.4 SD-14.57) performed a visual attention task. Participants were asked to identify a spatial probe at the top or the bottom of a screen, following either a bodily related (e.g., arm) or non-bodily related (e.g., clock) prime word. As predicted, when processing bodily-related words, patients with CD demonstrated a downwards attention bias. Moreover, the higher the patient's level of somatization, the faster the patient detected lower (vs upper) spatial targets. This study suggests that the changed health paradigm of patients with CD is grounded in sensorimotor perception. Further research could propose new diagnostic and treatment options for CD. Copyright © 2017 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

Numerical simulations of downward convective overshooting in giants

Science.gov (United States)

Tian, Chun-Lin; Deng, Li-Cai; Chan, Kwing-Lam

2009-09-01

An attempt at understanding downward overshooting in the convective envelopes of post-main-sequence stars has been made on the basis of three-dimensional large-eddy simulations, using artificially modified OPAL opacity and taking into account radiation and ionization in the equation of state. Two types of star, an intermediate-mass star and a massive star, were considered. To avoid a long thermal relaxation time of the intermediate-mass star, we increased the stellar energy flux artificially while trying to maintain a structure close to the one given by a 1D stellar model. A parametric study of the flux factor was performed. For the massive star, no such process was necessary. Numerical results were analysed when the system reached the statistical steady state. It was shown that the penetration distance in pressure scaleheights is of the order of unity. The scaling relations between penetration distance, input flux and vertical velocity fluctuations studied by Singh et al. were checked. The anisotropy of the turbulent convection and the diffusion models of the third-order moments representing the non-local transport were also investigated. These models are dramatically affected by the velocity fields and no universal constant parameters seem to exist. The limitations of the numerical results were also discussed.

Rivulet flow round a horizontal cylinder subject to a uniform surface shear stress

KAUST Repository

Paterson, C.; Wilson, S. K.; Duffy, B. R.

2014-01-01

large stationary horizontal cylinder subject to a prescribed uniform azimuthal surface shear stress is investigated. In particular, we focus on the case where the volume flux is downwards but the shear stress is upwards, for which there is always a

Far-zone contributions of airborne gravity anomalies' upward/downward continuation

Directory of Open Access Journals (Sweden)

Boyang Zhou

2016-11-01

Full Text Available Airborne gravimetry has become a vital technique in local gravity field approximation, and upward/downward continuation of gravity data is a key process of airborne gravimetry. In these procedures, the integral domain is divided into two parts, namely the near-zone and the far-zone. The far-zone contributions are approximated by the truncation coefficients and a global geo-potential model, and their values are controlled by several issues. This paper investigates the effects of flight height, the size of near-zone cap, and Remove-Compute-Restore (RCR technique upon far-zone contributions. Results show that at mountainous area the far-zone contributions can be ignored when EIGEN-6C of 360 degree is removed from the gravity data, together with a near-zone cap of 1° and a flight height less than 10 km, while at flat area EIGEN-6C of 180 degree is feasible.

Short-term variations in core surface flow resolved from an improved method of calculating observatory monthly means

Science.gov (United States)

Olsen, Nils; Whaler, Kathryn A.; Finlay, Christopher C.

2014-05-01

Monthly means of the magnetic field measurements taken by ground observatories are a useful data source for studying temporal changes of the core magnetic field and the underlying core flow. However, the usual way of calculating monthly means as the arithmetic mean of all days (geomagnetic quiet as well as disturbed) and all local times (day and night) may result in contributions from external (magnetospheric and ionospheric) origin in the (ordinary, omm) monthly means. Such contamination makes monthly means less favourable for core studies. We calculated revised monthly means (rmm), and their uncertainties, from observatory hourly means using robust means and after removal of external field predictions, using an improved method for characterising the magnetospheric ring current. The utility of the new method for calculating observatory monthly means is demonstrated by inverting their first differences for core surface advective flows. The flow is assumed steady over three consecutive months to ensure uniqueness; the effects of more rapid changes should be attenuated by the weakly conducting mantle. Observatory data are inverted directly for a regularised core flow, rather than deriving it from a secular variation spherical harmonic model. The main field is specified by the CHAOS-4 model. Data from up to 128 observatories between 1997 and 2013 were used to calculate 185 flow models from the omm and rmm, for each possible set of three consecutive months. The full 3x3 (non-diagonal) data covariance matrix was used, and two-norm (least squares) minimisation performed. We are able to fit the data to the target (weighted) misfit of 1, for both omm and rmm inversions, provided we incorporate the full data covariance matrix, and produce consistent, plausible flows. Fits are better for rmm flows. The flows exhibit noticeable changes over timescales of a few months. However, they follow rapid excursions in the omm that we suspect result from external field contamination

CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_TRMM-PFM-VIRS_Beta4)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2000-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

A comparison of ground reaction force components according to the foothold heights in 16-t truck during downward step.

Science.gov (United States)

Hyun, Seung-Hyun; Ryew, Che-Cheong

2017-12-01

The aim of this study is to compare and analyze the components of ground reaction force (GRF) relative to the foothold heights during downward step of 16-t truck. Adult males (n= 10) jumped downward from each 1st, 2nd, 3rd foothold step and driver's seat orderly using hand rail. Sampling rate of force components of 3 axis (medial-lateral [ML] GRF, anterior-posterior [AP] GRF, peak vertical force [PVF]), variables (COPx, COPy, COP area) of center of pressure (COP), loading rate, and stability index (ML, AP, vertical, and dynamic postural stability index [DPSI]) processed from GRF system was cut off at 1,000 Hz. and variables was processed with repeated one-way analysis of variance. AP GRF, PVF and loading rate showed higher value in case of not used hand rail than that used hand rail in all 1st, 2nd, and 3rd of foothold step. DPSI showed more lowered stability in order of 2nd, 3rd step than 1st foothold step used with hand rail, of which showed lowest stability from driver's seat. COPx, COPy, and COP area showed higher value in case of 2nd and 3rd than that of 1st of foothold step, and showed lowest stability from driver's seat. It is more desirable for cargo truck driver to utilize an available hand rail in order of 3rd, 2nd, and 1st of foothold step than downward stepping directly, thus by which may results in decrease of falling injuries and minimization of impulsive force transferring to muscular-skeletal system.

Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

Digital Repository Service at National Institute of Oceanography (India)

Martin, P.; Loeff, M.M.R. van der.; Cassar, N.; Vandromme, P.; d'Ovidio, F.; Stemmann, L.; Rengarajan, R.; Soares, M.A.; Gonzalez, H.E.; Ebersbach, F.; Lampitt, R.S.; Sanders, R.; Barnett, B.A.; Smetacek, V.; Naqvi, S.W.A.

A closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO₄), and the 300 km² fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux...

The downward spiral of chronic pain, prescription opioid misuse, and addiction: cognitive, affective, and neuropsychopharmacologic pathways.

Science.gov (United States)

Garland, Eric L; Froeliger, Brett; Zeidan, Fadel; Partin, Kaitlyn; Howard, Matthew O

2013-12-01

Prescription opioid misuse and addiction among chronic pain patients are emerging public health concerns of considerable significance. Estimates suggest that more than 10% of chronic pain patients misuse opioid analgesics, and the number of fatalities related to nonmedical or inappropriate use of prescription opioids is climbing. Because the prevalence and adverse consequences of this threat are increasing, there is a pressing need for research that identifies the biobehavioral risk chain linking chronic pain, opioid analgesia, and addictive behaviors. To that end, the current manuscript draws upon current neuropsychopharmacologic research to provide a conceptual framework of the downward spiral leading to prescription opioid misuse and addiction among chronic pain patients receiving opioid analgesic pharmacotherapy. Addictive use of opioids is described as the outcome of a cycle initiated by chronic pain and negative affect and reinforced by opioidergic-dopamingeric interactions, leading to attentional hypervigilance for pain and drug cues, dysfunctional connectivity between self-referential and cognitive control networks in the brain, and allostatic dysregulation of stress and reward circuitry. Implications for clinical practice are discussed; multimodal, mindfulness-oriented treatment is introduced as a potentially effective approach to disrupting the downward spiral and facilitating recovery from chronic pain and opioid addiction. Copyright © 2013 Elsevier Ltd. All rights reserved.

Study of the influence of water properties dependency with the temperature in a laminar downward flow between parallel flat plates

International Nuclear Information System (INIS)

Delmastro, Dario F.; Chasseur, A.F.; Garcia, Juan C.

2007-01-01

In this work we develop a model that contemplates stationary completely developed laminar downward flow between flat parallel plates with uniform and constant heat fluxes. The Boussinesq approach is used in the momentum equation, taking into account the change of the density with the temperature only in the gravitational term. The system is at atmospheric pressure and the dependencies of the density and the thermal conductivity with the temperature are also considered. The velocity and temperature profiles, the friction factor, the heat transfer coefficient and the Nusselt Number are calculated, for different flow rates and heating powers. The results allow to obtain some conclusions that can be of interest in the study of research reactors with forced downward refrigeration and flat plate fuels, although these calculations do not exactly represent the real behavior inside these channels. (author) [es

Dropout and downward mobility in the educational career: An event-history analysis of ethnic schooling differences in the Netherlands

NARCIS (Netherlands)

Kalmijn, M.; Kraaykamp, G.L.M.

2003-01-01

While many aspects of educational careers have been examined ill the literature on ethnic minorities, such as truancy, turnover and grades, downward mobility has rarely been studied. Using data on more than 10,000 students who entered secondary school in The Netherlands in 1989, we develop an

Dropout and Downward Mobility in the Educational Career : An Event-History Analysis of ethnic Schooling Differences in the Netherlands

NARCIS (Netherlands)

Kalmijn, M.; Kraaykamp, G.

2003-01-01

While many aspects of educational careers have been examined ill the literature on ethnic minorities, such as truancy, turnover and grades, downward mobility has rarely been studied. Using data on more than 10,000 students who entered secondary school in The Netherlands in 1989, we develop an

Kinematic differences exist between transtibial amputee fallers and non-fallers during downwards step transitioning.

Science.gov (United States)

Vanicek, Natalie; Strike, Siobhán C; Polman, Remco

2015-08-01

Stair negotiation is biomechanically more challenging than level gait. There are few biomechanical assessments of transtibial amputees descending stairs and none specifically related to falls. Stair descent may elicit more differences than level gait in amputees with and without a previous falls history. The aim of this study was to compare the gait kinematics of fallers and non-fallers during downwards step transitioning in transtibial amputees. Cross-sectional study. Six fallers and five non-fallers completed step transition trials on a three-step staircase at their self-selected pace. Nine participants exhibited a clear preference to lead with the affected limb, while two had no preference. Four participants self-selected a step-to rather than a reciprocal stair descent strategy. The fallers who used a reciprocal strategy walked 44% more quickly than the non-fallers. To compensate for the lack of active plantar flexion of the prosthetic foot, exaggerated range of motion occurred proximally at the pelvis during swing. The step-to group was more reliant on the handrails than the reciprocal group and walked more slowly. As anticipated, the fallers walked faster than the non-fallers despite employing the more difficult 'roll-over' technique. Handrail use could help to improve dynamic control during downwards step transitions. Transtibial amputees are advised to descend steps using external support, such as handrails, for enhanced dynamic control. Hip abductor and knee extensor eccentric strength should be improved through targeted exercise. Prosthetic socket fit should be checked to allow adequate knee range of motion on the affected side. © The International Society for Prosthetics and Orthotics 2014.

Monthly progress report

International Nuclear Information System (INIS)

1975-03-01

This monthly report of the SCPRI exposes an interpretation of the principal results concerning the surveillance of radioactivity in the environment: atmospheric dusts (air at ground level, high altitude air), rainwater, surface water, underground water, irrigation water, drinking water, food chain (milk, plants, cattle, fish), sea water around nuclear plant sites and other sites. The activities of various radioisotopes are presented in tables ( 7 Be, 95 Zr and 95 Nb, 103 Ru, 131 I, 137 Cs, 140 Ba and 140 La, 90 Sr, 106 Ru and 106 Rh, 226 Ra, 54 Mn, U and T). A monthly bibliographic selection is also presented [fr

Monthly progress report

International Nuclear Information System (INIS)

1975-06-01

This monthly report of the SCPRI exposes an interpretation of the principal results concerning the surveillance of radioactivity in the environment: atmospheric dusts(air at ground level, high altitude air), rainwater, surface water, underground water, irrigation water, drinking water, food chain (milk, plants, cattle, fish), sea water around nuclear plant sites and other sites. The activities of various radioisotopes are presented in tables ( 7 Be, 95 Zr and 95 Nb, 103 Ru, 131 I, 137 Cs, 140 Ba and 140 La, 90 Sr, 106 Ru and 106 Rh, 226 Ra, 54 Mn, U and T). A monthly bibliographic selection is also presented [fr

Monthly progress report

International Nuclear Information System (INIS)

1975-04-01

This monthly report of the SCPRI exposes an interpretation of the principal results concerning the surveillance of radioactivity in the environment: atmospheric dusts (air at ground level, high altitude air), rainwater, surface water, underground water, irrigation water, drinking water, food chain (milk plants, cattle, fish), seawater around nuclear plant sites and other sites. The activities of various radioisotopes are presented in tables ( 7 Be, 95 Zr and 95 Nb, 103 Ru, 131 I, 137 Cs, 140 Ba and 140 La, 90 Sr, 106 Ru and 106 Rh, 226 Ra, 54 Mn U and T). A monthly bibliographic selection is also presented [fr

Monthly progress report

International Nuclear Information System (INIS)

1975-01-01

This monthly report of the SCPRI exposes an interpretation of the principal results concerning the surveillance of radioactivity in the environment: atmospheric dusts (air at ground level, high altitude air), rainwater, surface water, underground water, irrigation water, drinking water, food chain (milk, plants, cattle, fish), sea water around nuclear plant sites and other sites. The activities of various radioisotopes are presented in tables ( 7 Be, 95 Zr and 95 Nb, 103 Ru, 131 I, 137 Cs, 140 Ba and 140 La, 90 Sr, 106 Ru and 106 Rh, 226 Ra, 54 Mn, U and T). A monthly bibliographic selection is also presented [fr

Monthly progress report

International Nuclear Information System (INIS)

1975-02-01

This monthly report of the SCPRI exposes an interpretation of the principal results concerning the surveillance of radioactivity in the environment: atmospheric dusts (air at ground level, high altitude air), rainwater, surface water, underground water, irrigation water, drinking water, food chain (milk, plants, cattle, fish), sea water around nuclear plant sites and other sites. The activities of various radioisotopes are presented in tables ( 7 Be, 95 Zr and 95 Nb, 103 Ru, 131 I, 137 Cs, 140 Ba and 140 La, 90 Sr, 106 Ru and 106 Rh, 226 Ra, 54 Mn, U and T). A monthly bibliographic selection is also presented [fr

One-dimensional critical heat flux concerning surface orientation and gap size effects

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Hoon; Suh, Kune Y. E-mail: kysuh@snu.ac.kr

2003-12-01

Tests were conducted to examine the critical heat flux (CHF) on a one-dimensional downward heating rectangular channel having a narrow gap by changing the orientation of the copper test heater assembly in a pool of saturated water under atmospheric pressure. The test parameters include both the gap sizes of 1, 2, 5 and 10 mm, and the surface orientation angles from the downward-facing position (180 deg.) to the vertical position (90 deg.), respectively. Also, the CHF experiments were performed for pool boiling with varying heater surface orientations in the unconfined space at atmospheric pressure using the rectangular test section. It was observed that the CHF generally decreases as the surface inclination angle increases and as the gap size decreases. In consistency with several studies reported in the literature, it was found that there exists a transition angle at which the CHF changes with a rapid slope. An engineering correlation is developed for the CHF during natural convective boiling in the inclined, confined rectangular channels with the aid of dimensional analysis. This correlation agrees with the experimental data of this study within {+-}20%.

Distribution and Downward Movement of Pasteuria penetrans in Field Soil.

Science.gov (United States)

Cetintas, R; Dickson, D W

2005-06-01

Endospores of Pasteuria penetrans were evaluated for their vertical distribution in field soil and their downward movement through soil in the laboratory. In the field trial, the number of endospores attached to second-stage juveniles (J2) of Meloidogyne arenaria race 1 varied greatly in different soil depths. There were higher percentages of J2 with endospores attached in former weed fallow plots during the first 3 years of growing peanut than in former bahiagrass and rhizomal peanut plots (P 0.05). In laboratory trials, P. penetrans endospores were observed to move throughout the soil through the percolation of water. After one application of water, some endospores were detected 25 to 37.5 cm deep. Endospores were present at the greatest depth, 37.5 to 50 cm, after the third application of water. These results indicate that rain or water applications by irrigation are likely to move endospores to deeper levels of the soil, but the majority of endospores remain in the upper 0-to-30-cm depth.

Characteristics of downward leaders in a cloud-to-ground lightning strike on a lightning rod

Science.gov (United States)

Wang, Caixia; Sun, Zhuling; Jiang, Rubin; Tian, Yangmeng; Qie, Xiushu

2018-05-01

A natural downward negative cloud-to-ground (CG) lightning was observed at a close distance of 370 m by using electric field change measurements and a high-speed camera at 5400 frames per second (fps). Two subsequent leader-return strokes of the lightning hit a lightning rod installed on the top of a seven-story building in Beijing city, while the grounding point for the stepped leader-first return stroke was 12 m away, on the roof of the building. The 2-D average speed of the downward stepped leader (L1) before the first return stroke (R1) was approximately 5.1 × 104 m/s during its propagation over the 306 m above the building, and those before the subsequent strokes (R2 and R3) ranged from 1.1 × 106 m/s to 2.2 × 106 m/s. An attempted leader (AL) occurred 201 ms after R1 and 10 ms before R2 reached approximately 99 m above the roof and failed to connect to the ground. The 2-D average speed of the AL was approximately 7.4 × 104 m/s. The luminosity at tip of the leader was brighter than the channel behind it. The leader inducing the R2 with an alteration of terminating point was a dart-stepped leader (DSL), which propagated through the channel of AL and continued to develop downward with new branches at about 17 m above the roof. The 2-D speed of the DSL at the bottom 99 m was 6.6 × 105 m/s. The average time interval between the stepped pulses of the DSL was approximately 10 μs, smaller than that of L1 with value of about 17 μs. The average step lengths of the DSL were approximately 6.6 m. The study shows that the stepped leader-first return stroke of lightning will not always hit the tip of a tall metal rod due to the significant branching property of the leader. However, under certain conditions, the subsequent return strokes may alter the grounding point to the tip of a tall metal rod. For the lightning rod, the protection against subsequent return strokes may be better than that against the first return stroke.

Collector Efficiency in Downward-Type Internal-Recycle Solar Air Heaters with Attached Fins

Directory of Open Access Journals (Sweden)

Chii-Dong Ho

2013-10-01

Full Text Available The internal-recycle operation effect on collector efficiency in downward-type rectangular solar air heaters with attached fins is theoretically investigated. It is found that considerable collector efficiency is obtainable if the collector has attached fins and the operation is carried out with internal recycling. The recycling operation increases the fluid velocity to decrease the heat transfer resistance, compensating for the undesirable effect of decreasing the heat transfer driving force (temperature difference due to remixing. The attached fins provide an enlarged heat transfer area. The order of performance in a device of same size is: double pass with recycle and fins > double pass with recycle but without fins > single pass without recycle and fins.

Concepts of self-acting circulation loops for downward heat transfer (reverse thermosiphons)

International Nuclear Information System (INIS)

Dobriansky, Y.

2011-01-01

This paper reviews the scientific and technical knowledge related to general self-acting flow loops (thermosiphons and heat pipes) that transmit heat upwards and self-acting reverse flow loops that transmit heat downwards. This paper classifies the heat and mass transfer processes that take place in general flow loops and analyses the nomenclature applied in the literature. It also presents the principles of operation of sixteen reverse flow loops; four of the loops are powered by an external source of energy, while the remaining loops are self-acting. Of the self-acting loops, vapor was used for heat transfer in seven of them and liquid was used in the remaining ones. Based on the available research results, a list of the advantages and disadvantages of both types of loops is presented.

Effects of fuel properties on the natural downward smoldering of piled biomass powder: Experimental investigation

International Nuclear Information System (INIS)

He, Fang; Yi, Weiming; Li, Yongjun; Zha, Jianwen; Luo, Bin

2014-01-01

To validate the modeling of one-dimensional biomass smoldering and combustion, the effects of fuel type, moisture content and particle size on the natural downward smoldering of biomass powder have been investigated experimentally. A cylindrical reactor (inner size Φ26 cm × 22 cm) was constructed, and corn stalk, pine trunk, pyrolysis char and activated char from corn stalk were prepared as powders. The smoldering characteristics were examined for each of the four materials and for different moisture contents and particle sizes. The results revealed the following: 1) The maximum temperature in the fuel bed is only slightly affected by the fuel type and particle size. It increases gradually for original biomass and decreases slowly for chars with the development of the process. 2) The propagation velocity of the char oxidation front is significantly affected by the carbon density and ash content and nearly unaffected by moisture content and particle size. 3) The propagation velocity of the drying front is significantly affected by the moisture content, decreasing from over 10 times the propagation velocity of char oxidation front to about 3 times as the moisture content increased from 3 to 21%. - Highlights: • Natural downward smoldering of four materials, different moisture contents, and different particle sizes were investigated. • Propagation velocity of the char oxidation front differs significantly from that of the drying front. • Carbon density and ash content of fuel significantly affect propagation velocity of the char oxidation front

MERRA 2D IAU Ocean Surface Diagnostic, Single Level, Monthly Mean (2/3x1/2L1) V5.2.0

Data.gov (United States)

National Aeronautics and Space Administration — The MATMNXOCN or tavgM_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is monthly mean...

Statistical significance of trends in monthly heavy precipitation over the US

KAUST Repository

Mahajan, Salil

2011-05-11

Trends in monthly heavy precipitation, defined by a return period of one year, are assessed for statistical significance in observations and Global Climate Model (GCM) simulations over the contiguous United States using Monte Carlo non-parametric and parametric bootstrapping techniques. The results from the two Monte Carlo approaches are found to be similar to each other, and also to the traditional non-parametric Kendall\\'s τ test, implying the robustness of the approach. Two different observational data-sets are employed to test for trends in monthly heavy precipitation and are found to exhibit consistent results. Both data-sets demonstrate upward trends, one of which is found to be statistically significant at the 95% confidence level. Upward trends similar to observations are observed in some climate model simulations of the twentieth century, but their statistical significance is marginal. For projections of the twenty-first century, a statistically significant upwards trend is observed in most of the climate models analyzed. The change in the simulated precipitation variance appears to be more important in the twenty-first century projections than changes in the mean precipitation. Stochastic fluctuations of the climate-system are found to be dominate monthly heavy precipitation as some GCM simulations show a downwards trend even in the twenty-first century projections when the greenhouse gas forcings are strong. © 2011 Springer-Verlag.

Experimental study of the effect of the reduced graphene oxide films on nucleate boiling performances of inclined surfaces

International Nuclear Information System (INIS)

Kim, Ji Hoon; Kong, Byeong Tak; Kim, Ji Min

2016-01-01

For the enhancing the CHF, surface coating techniques are available. Yang et al. performed small scale boiling experiments for the vessel lower head, which was coated by aluminum/copper micro particles. Recently, graphene has received much attention for applications in thermal engineering due to its large thermal conductivity. Ahn et al. used a silicon dioxide substrate, which was coated graphene films, as a heating surface during pool boiling experiments. The graphene films inhibited the formation of hot spots, increasing the CHF. For applying novel material 'Graphene' in nuclear industry, here we investigated the effects of graphene film coatings on boiling performances. The experimental pool boiling facility, copying the geometry of lower head of reactor, was designed for verifying orientation effects. The effects of graphene films coating on varied inclined heater surfaces were investigated. The CHF values were increased at every case, but the increased amounts were decreased for downward heater surfaces. At the downward-facing region, however, coating the RGO films would change the CHF mechanisms and boiling heat transfer performances. Generally, RGO films, made by colloidal fabrication, has defects on each flakes.

Radionuclide transfer onto ground surface in surface water flow, 1

International Nuclear Information System (INIS)

Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu; Kamiyama, Hideo

1991-07-01

Radionuclides migration in ground surface water flow is considered to be one of the important path way in the scenario for environmental migration of radionuclides leaked from low level radioactive waste repository. Simulating the slightly sloped surface on which contaminated solution is flowing downward, testing for radionuclide migration on ground surface had been started. As it's first step, an experiment was carried out under the condition of restricted infiltration in order to elucidate the adsorption behavior of radionuclides onto the loamy soil surface in related with hydraulic conditions. Radionuclides concentration change in effluent solution with time and a concentration distribution of radionuclides adsorbed on the ground surface were obtained from several experimental conditions combining the rate and the duration time of the water flow. The radionuclides concentration in the effluent solution was nearly constant during each experimental period, and was reduced under the condition of lower flow rate. The surface distribution of radionuclides concentration showed two distinctive regions. The one was near the inlet vessel where the concentration was promptly reducing, and the other was following the former where the concentration was nearly constant. The characteristic surface distribution of radionuclides concentration can be explained by a two dimensional diffusion model with a first order adsorption reaction, based on the advection of flow rate distribution in perpendicular direction. (author)

Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

NARCIS (Netherlands)

Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

2002-01-01

Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores

Diagnostic model of 3-D circulation in the Arabian Sea and western equatorial Indian Ocean: Results of monthly mean sea surface topography

Digital Repository Service at National Institute of Oceanography (India)

Bahulayan, N.; Shaji, C.

A three-dimensional diagnostic model has been developed to compute the monthly mean circulation and sea surface topography in the Western Tropical Indian Ocean north of 20 degrees S and west of 80 degrees E. The diagnostic model equations...

CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM1-MODIS_Edition2B)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-10-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM2-MODIS_Edition2A)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Aqua-FM3-MODIS_Edition2A)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM2-MODIS_Edition2C)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

An Experimental Study on the Pool Boiling Heat Transfer on a Square Surface

International Nuclear Information System (INIS)

Kim, Jae Kwang

2000-02-01

An experimental study was carried out to identify the various regimes of natural convective boiling and to determine the Critical Heat Flux (CHF) on a square surface. The basic knowledge on the boiling heat transfer and CHF on the square surface is necessary for various engineering problems, such as the design of compact heat exchangers, cooling of CPU chips, and design of the external cooling mechanism for the reactor during the severe accidents in the nuclear power plants. The heater block made of copper with cartridge heaters in it is submerged in a water tank with windows for visualization. The heater surface has dimension of 70mm x 70mm and the maximum heat flux capacity is about 1.8MW/m 2 . The boiling heat transfer coefficient for the various flow regimes up to CHF has been measured for upward facing surface, vertical surface, and nearly horizontal downward facing surfaces. The temperatures of the heater block are measured by the thermocouples imbedded in the heater block. As the heat flux increases from 100kW/m 2 to 1.0MW/m 2 , the heat-transfer regime changes from the nucleate boiling to the CHF. Near 1.0MW/m 2 , the heat transfer regime suddenly changed from nucleate boiling to film boiling and it resulted in a rapid heat up of the heater block. The various boiling patterns on the vertical surface, upward facing surface, and downward facing surface are observed by a high speed video camera whose frame rate is 1000fps. An explosive vapor generation on the heated surface, whose size and frequency are characterized by the heat flux and inclination angle, is observed

Correcting surface solar radiation of two data assimilation systems against FLUXNET observations in North America

Science.gov (United States)

Zhao, Lei; Lee, Xuhui; Liu, Shoudong

2013-09-01

Solar radiation at the Earth's surface is an important driver of meteorological and ecological processes. The objective of this study is to evaluate the accuracy of the reanalysis solar radiation produced by NARR (North American Regional Reanalysis) and MERRA (Modern-Era Retrospective Analysis for Research and Applications) against the FLUXNET measurements in North America. We found that both assimilation systems systematically overestimated the surface solar radiation flux on the monthly and annual scale, with an average bias error of +37.2 Wm-2 for NARR and of +20.2 Wm-2 for MERRA. The bias errors were larger under cloudy skies than under clear skies. A postreanalysis algorithm consisting of empirical relationships between model bias, a clearness index, and site elevation was proposed to correct the model errors. Results show that the algorithm can remove the systematic bias errors for both FLUXNET calibration sites (sites used to establish the algorithm) and independent validation sites. After correction, the average annual mean bias errors were reduced to +1.3 Wm-2 for NARR and +2.7 Wm-2 for MERRA. Applying the correction algorithm to the global domain of MERRA brought the global mean surface incoming shortwave radiation down by 17.3 W m-2 to 175.5 W m-2. Under the constraint of the energy balance, other radiation and energy balance terms at the Earth's surface, estimated from independent global data products, also support the need for a downward adjustment of the MERRA surface solar radiation.

Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Energy Technology Data Exchange (ETDEWEB)

Vihma, T.

1995-12-31

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Energy Technology Data Exchange (ETDEWEB)

Vihma, T

1996-12-31

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects

Photoelectric emission from negative-electron-affinity diamond (111) surfaces: Exciton breakup versus conduction-band emission

International Nuclear Information System (INIS)

Bandis, C.; Pate, B.B.

1995-01-01

We have recently reported that bound electron-hole pairs (Mott-Wannier excitons) are the dominant source of photoelectron emission from specially prepared [''as-polished'' C(111)-(1x1):H] negative-electron-affinity diamond surfaces for near-band-gap excitation up to 0.5 eV above threshold [C. Bandis and B. B. Pate, Phys. Rev. Lett. 74, 777 (1995)]. It was found that photoexcited excitons transport to the surface, break up, and emit their electron. In this paper, we extend the study of exciton-derived emission to include partial yield (constant final-state) analysis as well as angular distribution measurements of the photoelectric emission. In addition, we find that exciton-derived emission does not always dominate. Photoelectric emission properties of the in situ ''rehydrogenated'' (111)-(1x1):H diamond surface are characteristically different than emission observed from the as-polished (111)-(1x1):H surface. The rehydrogenated surface has additional downward band bending as compared to the as-polished surface. In confirmation of the assignment of photoelectric yield to exciton breakup emission, we find a significant enhancement of the total electron yield when the downward band bending of the hydrogenated surface is increased. The functional form of the observed total electron yield demonstrates that, in contrast to the as-polished surface, conduction-band electrons are a significant component of the observed photoelectric yield from the in situ hydrogenated (111)-(1x1):H surface. Furthermore, electron emission characteristics of the rehydrogenated surface confirms our assignment of a Fan phonon-cascade mechanism for thermalization of excitons

A simple way of characterizing X-ray downwards-deflecting mirror-bender assemblies using the long trace profiler

International Nuclear Information System (INIS)

Assoufid, L.; Her, P.

1999-01-01

A simple device composed of a modular double-pentaprism system that enables the long trace profiler (LTP) to measure mirrors in nonconventional ways, i.e., in the vertical-downward and sideways positions, has been devised and implemented in the Advanced Photon Source (APS) long trace profiler (LTP II). The systems is very useful in calibrating mirror-bender assemblies. This paper describes the system and gives results of measurements performed with it on a mirror used at the APS

Experimental observation of pulsating instability under acoustic field in downward-propagating flames at large Lewis number

KAUST Repository

Yoon, Sung Hwan

2017-10-12

According to previous theory, pulsating propagation in a premixed flame only appears when the reduced Lewis number, β(Le-1), is larger than a critical value (Sivashinsky criterion: 4(1 +3) ≈ 11), where β represents the Zel\\'dovich number (for general premixed flames, β ≈ 10), which requires Lewis number Le > 2.1. However, few experimental observation have been reported because the critical reduced Lewis number for the onset of pulsating instability is beyond what can be reached in experiments. Furthermore, the coupling with the unavoidable hydrodynamic instability limits the observation of pure pulsating instabilities in flames. Here, we describe a novel method to observe the pulsating instability. We utilize a thermoacoustic field caused by interaction between heat release and acoustic pressure fluctuations of the downward-propagating premixed flames in a tube to enhance conductive heat loss at the tube wall and radiative heat loss at the open end of the tube due to extended flame residence time by diminished flame surface area, i.e., flat flame. The thermoacoustic field allowed pure observation of the pulsating motion since the primary acoustic force suppressed the intrinsic hydrodynamic instability resulting from thermal expansion. By employing this method, we have provided new experimental observations of the pulsating instability for premixed flames. The Lewis number (i.e., Le ≈ 1.86) was less than the critical value suggested previously.

Simultaneous solution of the geoid and the surface density anomalies

Science.gov (United States)

Ardalan, A. A.; Safari, A.; Karimi, R.; AllahTavakoli, Y.

2012-04-01

The main application of the land gravity data in geodesy is "local geoid" or "local gravity field" modeling, whereas the same data could play a vital role for the anomalous mass-density modeling in geophysical explorations. In the realm of local geoid computations based on Geodetic Boundary Value Problems (GBVP), it is needed that the effect of the topographic (or residual terrain) masses be removed via application of the Newton integral in order to perform the downward continuation in a harmonic space. However, harmonization of the downward continuation domain may not be perfectly possible unless accurate information about the mass-density of the topographic masses be available. On the other hand, from the exploration point of view the unwanted topographical masses within the aforementioned procedure could be regarded as the signal. In order to overcome the effect of the remaining masses within the remove step of the GBVP, which cause uncertainties in mathematical modeling of the problem, here we are proposing a methodology for simultaneous solution of the geoid and residual surface density modeling In other words, a new mathematical model will be offered which both provides the needed harmonic space for downward continuation and at the same time accounts for the non-harmonic terms of gravitational field and makes use of it for residual mass density modeling within the topographic region. The presented new model enjoys from uniqueness of the solution, opposite to the inverse application of the Newton integral for mass density modeling which is non-unique, and only needs regularization to remove its instability problem. In this way, the solution of the model provides both the incremental harmonic gravitational potential on surface of the reference ellipsoid as the gravity field model and the lateral surface mass-density variations via the second derivatives of the non harmonic terms of gravitational field. As the case study and accuracy verification, the proposed

Electric controlling of surface metal-insulator transition in the doped BaTiO3 film

Directory of Open Access Journals (Sweden)

Wei Xun

2017-07-01

Full Text Available Based on first-principles calculations, the BaTiO3(BTO film with local La-doping is studied. For a selected concentration and position of doping, the surface metal-insulator transition occurs under the applied electric field, and the domain appears near the surface for both bipolar states. Furthermore, for the insulated surface state, i.e., the downward polarization state in the doped film, the gradient bandgap structure is achieved, which favors the absorption of solar energy. Our investigation can provide an alternative avenue in modification of surface property and surface screening effect in polar materials.

Properties of the histogram location approach and the extent and change of downward nominal wage rigidity in the EU

Directory of Open Access Journals (Sweden)

Andreas Behr

2006-06-01

Full Text Available The histogram location approach has been proposed by Kahn (1997 to estimate the fraction of wage cuts prevented by downward nominal wage rigidity. In this paper, we analyze the validity of the approach by means of a simulation study which yielded evidence of unbiasedness but also of potential underestimation of rigidity parameter uncertainty and therefore of potential anticonservative inference. We apply the histogram location approach to estimate the extent of downward nominal wage rigidity across the EU for 1995-2001. Our data base is the User Data Base (UDB of the European Community Household Panel (ECHP. The results show wide variation in the fraction of wage cuts prevented by nominal wage rigidity across the EU. The lowest rigidity parameters are found for the UK, Spain and Ireland, the largest for Portugal and Italy. Analyzing the change of rigidity between sub periods 1995-1997 and 1999-2001 even shows an widening of the differences in nominal wage rigidity. Due to the finding of large differences across the EU, the results imply that the costs of low inflation policies across the EU differ substantially.

Bread and Shoulders: Reversing the Downward Spiral, a Qualitative Analyses of the Effects of a Housing First-Type Program in France

Science.gov (United States)

Rhenter, Pauline; Moreau, Delphine; Laval, Christian; Mantovani, Jean; Albisson, Amandine; Suderie, Guillaume; Boucekine, Mohamed; Tinland, Aurelie; Loubière, Sandrine; Greacen, Tim; Auquier, Pascal; Girard, Vincent

2018-01-01

This paper is a qualitative analysis of the effects of accompagnement, a support framework, on recovery trajectories of people with long-term homelessness and severe psychiatric disorders during 24 months in a Housing First-type program in France. A comprehensive methodology based on grounded theory was used to construct an interview guide, conduct multiple interviews with 35 Housing First participants sampled for heterogeneity, and produce memos on their trajectories before and after entering the program based on interview information. Thematic analysis of a representative subsample (n = 13) of memos identified 12 objective factors and 6 subjective factors key to the recovery process. An in-depth re-analysis of the memos generated four recovery themes: (1) the need for secure space favorable to self-reflexivity; (2) a “honeymoon” effect; (3) the importance of even weak social ties; (4) support from and hope among peers. Three challenges to recovery were identified: (1) finding a balance between protection and risk; (2) breaking downward spirals; (3) bifurcating the trajectory. This study provides new insight into the recovery process, understood as a non-linear transformation of an experience—the relationship between objective life conditions and subjective perception of those conditions—which reinforces protective support over risk elements. PMID:29538346

Bread and Shoulders: Reversing the Downward Spiral, a Qualitative Analyses of the Effects of a Housing First-Type Program in France

Directory of Open Access Journals (Sweden)

Pauline Rhenter

2018-03-01

Full Text Available This paper is a qualitative analysis of the effects of accompagnement, a support framework, on recovery trajectories of people with long-term homelessness and severe psychiatric disorders during 24 months in a Housing First-type program in France. A comprehensive methodology based on grounded theory was used to construct an interview guide, conduct multiple interviews with 35 Housing First participants sampled for heterogeneity, and produce memos on their trajectories before and after entering the program based on interview information. Thematic analysis of a representative subsample (n = 13 of memos identified 12 objective factors and 6 subjective factors key to the recovery process. An in-depth re-analysis of the memos generated four recovery themes: (1 the need for secure space favorable to self-reflexivity; (2 a “honeymoon” effect; (3 the importance of even weak social ties; (4 support from and hope among peers. Three challenges to recovery were identified: (1 finding a balance between protection and risk; (2 breaking downward spirals; (3 bifurcating the trajectory. This study provides new insight into the recovery process, understood as a non-linear transformation of an experience—the relationship between objective life conditions and subjective perception of those conditions—which reinforces protective support over risk elements.

Bread and Shoulders: Reversing the Downward Spiral, a Qualitative Analyses of the Effects of a Housing First-Type Program in France.

Science.gov (United States)

Rhenter, Pauline; Moreau, Delphine; Laval, Christian; Mantovani, Jean; Albisson, Amandine; Suderie, Guillaume; Boucekine, Mohamed; Tinland, Aurelie; Loubière, Sandrine; Greacen, Tim; Auquier, Pascal; Girard, Vincent

2018-03-14

This paper is a qualitative analysis of the effects of accompagnement , a support framework, on recovery trajectories of people with long-term homelessness and severe psychiatric disorders during 24 months in a Housing First-type program in France. A comprehensive methodology based on grounded theory was used to construct an interview guide, conduct multiple interviews with 35 Housing First participants sampled for heterogeneity, and produce memos on their trajectories before and after entering the program based on interview information. Thematic analysis of a representative subsample ( n = 13) of memos identified 12 objective factors and 6 subjective factors key to the recovery process. An in-depth re-analysis of the memos generated four recovery themes: (1) the need for secure space favorable to self-reflexivity; (2) a "honeymoon" effect; (3) the importance of even weak social ties; (4) support from and hope among peers. Three challenges to recovery were identified: (1) finding a balance between protection and risk; (2) breaking downward spirals; (3) bifurcating the trajectory. This study provides new insight into the recovery process, understood as a non-linear transformation of an experience-the relationship between objective life conditions and subjective perception of those conditions-which reinforces protective support over risk elements.

Experimental study of the effect of the reduced graphene oxide films on nucleate boiling performances of inclined surfaces

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji Hoon; Kong, Byeong Tak [Incheon National University, Incheon (Korea, Republic of); Kim, Ji Min [POSTECH, Pohang (Korea, Republic of); and others

2016-05-15

For the enhancing the CHF, surface coating techniques are available. Yang et al. performed small scale boiling experiments for the vessel lower head, which was coated by aluminum/copper micro particles. Recently, graphene has received much attention for applications in thermal engineering due to its large thermal conductivity. Ahn et al. used a silicon dioxide substrate, which was coated graphene films, as a heating surface during pool boiling experiments. The graphene films inhibited the formation of hot spots, increasing the CHF. For applying novel material 'Graphene' in nuclear industry, here we investigated the effects of graphene film coatings on boiling performances. The experimental pool boiling facility, copying the geometry of lower head of reactor, was designed for verifying orientation effects. The effects of graphene films coating on varied inclined heater surfaces were investigated. The CHF values were increased at every case, but the increased amounts were decreased for downward heater surfaces. At the downward-facing region, however, coating the RGO films would change the CHF mechanisms and boiling heat transfer performances. Generally, RGO films, made by colloidal fabrication, has defects on each flakes.

Impacts of sea-surface salinity in an eddy-resolving semi-global OGCM

Science.gov (United States)

Furue, Ryo; Takatama, Kohei; Sasaki, Hideharu; Schneider, Niklas; Nonaka, Masami; Taguchi, Bunmei

2018-02-01

To explore the impacts of sea-surface salinity (SSS) on the interannual variability of upper-ocean state, we compare two 10-year runs of an eddy-resolving ocean general circulation model (OGCM): in one, SSS is strongly restored toward a monthly climatology (World Ocean Atlas '98) and in the other, toward the SSS of a monthly gridded Argo product. The inclusion of the Argo SSS generally improves the interannual variability of the mixed layer depth; particularly so in the western tropical Pacific, where so-called "barrier layers" are reproduced when the Argo SSS is included. The upper-ocean subsurface salinity variability is also improved in the tropics and subtropics even below the mixed layer. To understand the reason for the latter improvement, we separate the salinity difference between the two runs into its "dynamical" and "spiciness" components. The dynamical component is dominated by small-scale noise due to the chaotic nature of mesoscale eddies. The spiciness difference indicates that as expected from the upper-ocean general circulation, SSS variability in the mixed layer is subducted into the thermocline in subtropics; this signal is generally advected downward, equatorward, and westward in the equator-side of the subtropical gyre. The SSS signal subducted in the subtropical North Pacific appears to enter the Indian Ocean through the Indonesian Throughflow, although this signal is weak and probably insignificant in our model.

Adsorption properties of AlN on Si(111) surface: A density functional study

Science.gov (United States)

Yuan, Yinmei; Zuo, Ran; Mao, Keke; Tang, Binlong; Zhang, Zhou; Liu, Jun; Zhong, Tingting

2018-04-01

In the process of preparing GaN on Si substrate by MOCVD, an AlN buffer layer is very important. In this study, we conducted density functional theory calculations on the adsorption of AlN molecule on Si(111)-(2 × 2) surface, with the AlN molecule located horizontally or vertically above Si(111) surface at different adsorption sites. The calculations revealed that the lowest adsorption energy was at the N-top-Al-bridge site in the horizontal configuration, with the narrowest band gap, indicating that it was the most preferential adsorption growth status of AlN. In the vertical configurations, N adatom was more reactive and convenient to form bonds with the topmost Si atoms than Al adatom. When the N-end of the AlN molecule was located downward, the hollow site was the preferred adsorption site; when the Al-end was located downward, the bridge site was the most energetically favorable. Moreover, we investigated some electronic properties such as partial density of states, electron density difference, Mulliken populations, etc., revealing the microscale mechanism for AlN adsorption on Si(111) surface and providing theoretical support for adjusting the processing parameters during AlN or GaN production.

Heavy mineral sorting in downwards injected Palaeocene sandstone, Siri Canyon, Danish North Sea

DEFF Research Database (Denmark)

Kazerouni, Afsoon Moatari; Friis, Henrik; Svendsen, Johan Byskov

2011-01-01

Post-depositional remobilization and injection of sand are often seen in deep-water clastic systems and has been recently recognised as a significant modifier of deep-water sandstone geometry. Large-scale injectite complexes have been interpreted from borehole data in the Palaeocene Siri Canyon...... of depositional structures in deep-water sandstones, the distinction between "in situ" and injected or remobilised sandstones is often ambiguous. Large scale heavy mineral sorting (in 10 m thick units) is observed in several reservoir units in the Siri Canyon and has been interpreted to represent the depositional...... sorting. In this study we describe an example of effective shear-zone sorting of heavy minerals in a thin downward injected sandstone dyke which was encountered in one of the cores in the Cecilie Field, Siri Canyon. Differences in sorting pattern of heavy minerals are suggested as a tool for petrographic...

1994 Average Monthly Sea Surface Temperature for California

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

1993 Average Monthly Sea Surface Temperature for California

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the NOAA...

Monthly Climatic Data for the World

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Publication of monthly mean temperature, pressure, precipitation, vapor pressure, and hours of sunshine for approximately 2,000 surface data collection stations...

An Experimental Study on the Convective Heat Transfer in Narrow Rectangular Channels for Downward Flow to Predict Onset of Nucleate Boiling

International Nuclear Information System (INIS)

Song, Junghyun; Jeong, Yong Hoon; Lee, Juhyung; Chang, Soon Heung

2014-01-01

Research reactor is the nuclear reactor serves neutron source for many research fields such as neutron scattering, non-destructive testing, radioisotope treatment and so on. Due to that characteristic of research reactor, as many people work around the research reactor, research reactor should be designed to have much more conservative margin for normal operation. Boiling heat transfer is the one of the most efficient type in heat transfer modes, however, research reactor needs to avoid onset of nucleate boiling (ONB) in normal operation as IAEA recommend for research reactors to have enough ONB margin to maintain the normal operation state in 'IAEA-TECDOC-233' (1980) for the same reason explained above. Jordan Research and Training Reactor (JRTR) operates under downward flow in narrow rectangular channel in fuel assembly. There isn't sufficient heat transfer data under downward flow condition and only few ONB prediction correlation as well. In the present work, not only a new ONB prediction model would be developed, but also comparison between heat transfer data with several heat transfer correlations could be shown. In addition, as Sudo and Omar S. proposed differently about the Nusselt number behaviors in upward and downward convective heat transfer, the study of convective heat transfer should be conducted continuously to determine it exactly. In this paper, single-phase heat transfer data is analyzed by several heat transfer correlations before developing ONB prediction correlation. In this study, an experiment on the single-phase heat transfer was conducted. As shown in Fig. 5, comparison between experimental data and existing correlations shows quite huge difference as about 40%. Additional experiments on single-phase heat transfer at low heat flux are necessary to clarify the tendency of Nusselt number among heat flux and to develop new correlation for single-phase heat transfer

Presbycusis: a human temporal bone study of individuals with downward sloping audiometric patterns of hearing loss and review of the literature.

Science.gov (United States)

Nelson, Erik G; Hinojosa, Raul

2006-09-01

The purpose of this retrospective case review was to identify patterns of cochlear element degeneration in individuals with presbycusis exhibiting downward sloping audiometric patterns of hearing loss and to correlate these findings with those reported in the literature to clarify conflicting concepts regarding the association between hearing loss and morphologic abnormalities. Archival human temporal bones from individuals with presbycusis were selected on the basis of strict audiometric criteria for downward-sloping audiometric thresholds. Twenty-one temporal bones that met these criteria were identified and compared with 10 temporal bones from individuals with normal hearing. The stria vascularis volumes, spiral ganglion cell populations, inner hair cells, and outer hair cells were quantitatively evaluated. The relationship between the severity of hearing loss and the degeneration of cochlear elements was analyzed using univariate linear regression models. Outer hair cell loss and ganglion cell loss was observed in all individuals with presbycusis. Inner hair cell loss was observed in 18 of the 21 individuals with presbycusis and stria vascularis loss was observed in 10 of the 21 individuals with presbycusis. The extent of degeneration of all four of the cochlear elements evaluated was highly associated with the severity of hearing loss based on audiometric thresholds at 8,000 Hz and the pure-tone average at 500, 1,000, and 2,000 Hz. The extent of ganglion cell degeneration was associated with the slope of the audiogram. Individuals with downward-sloping audiometric patterns of presbycusis exhibit degeneration of the stria vascularis, spiral ganglion cells, inner hair cells, and outer hair cells that is associated with the severity of hearing loss. This association has not been previously reported in studies that did not use quantitative methodologies for evaluating the cochlear elements and strict audiometric criteria for selecting cases.

Is tropospheric weather influenced by solar wind through atmospheric vertical coupling downward control?

Science.gov (United States)

Prikryl, Paul; Tsukijihara, Takumi; Iwao, Koki; Muldrew, Donald B.; Bruntz, Robert; Rušin, Vojto; Rybanský, Milan; Turňa, Maroš; Šťastný, Pavel; Pastirčák, Vladimír

2017-04-01

More than four decades have passed since a link between solar wind magnetic sector boundary structure and mid-latitude upper tropospheric vorticity was discovered (Wilcox et al., Science, 180, 185-186, 1973). The link has been later confirmed and various physical mechanisms proposed but apart from controversy, little attention has been drawn to these results. To further emphasize their importance we investigate the occurrence of mid-latitude severe weather in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system. It is observed that significant snowstorms, windstorms and heavy rain, particularly if caused by low pressure systems in winter, tend to follow arrivals of high-speed solar wind. Previously published statistical evidence that explosive extratropical cyclones in the northern hemisphere tend to occur after arrivals of high-speed solar wind streams from coronal holes (Prikryl et al., Ann. Geophys., 27, 1-30, 2009; Prikryl et al., J. Atmos. Sol.-Terr. Phys., 149, 219-231, 2016) is corroborated for the southern hemisphere. A physical mechanism to explain these observations is proposed. The leading edge of high-speed solar wind streams is a locus of large-amplitude magneto-hydrodynamic waves that modulate Joule heating and/or Lorentz forcing of the high-latitude lower thermosphere generating medium-scale atmospheric gravity waves that propagate upward and downward through the atmosphere. Simulations of gravity wave propagation in a model atmosphere using the Transfer Function Model (Mayr et al., Space Sci. Rev., 54, 297-375, 1990) show that propagating waves originating in the thermosphere can excite a spectrum of gravity waves in the lower atmosphere. In spite of significantly reduced amplitudes but subject to amplification upon reflection in the upper troposphere, these gravity waves can provide a lift of unstable air to release instabilities in the troposphere thus initiating convection to form cloud/precipitation bands

Analysis of Tube Bank Heat Transfer In Downward Directed Foam Flow

Directory of Open Access Journals (Sweden)

Jonas Gylys

2004-06-01

Full Text Available Apparatus with the foam flow are suitable to use in different technologies like heat exchangers, food industry, chemical and oil processing industry. Statically stable liquid foam until now is used in technologic systems rather seldom. Although a usage of this type of foam as heat transfer agent in foam equipment has a number of advantages in comparison with one phase liquid equipment: small quantity of liquid is required, heat transfer rate is rather high, mass of equipment is much smaller, energy consumption for foam delivery into heat transfer zone is lower. The paper analyzes the peculiarities of heat transfer from distributed in staggered order and perpendicular to foam flow in channel of rectangular cross section tube bundle to the foam flow. It was estimated the dependence of mean gas velocity and volumetric void fraction of foam flow to heat transfer in downward foam flow. Significant difference of heat transfer intensity from front and back tubes of tube row in laminar foam flow was noticed. Dependence of heat transfer on flow velocity and volumetric void fraction of foam was confirmed and estimated by criterion equations.

Correlation for downward melt penetration into a miscible low-density substrate

International Nuclear Information System (INIS)

Fang, L.J.; Cheung, F.B.; Pedersen, D.R.; Linehan, J.H.

1984-01-01

Downward penetration of a sacrificial bed material or a concrete basemat structure by an overlying layer of core melt resulting from a hypothetical core disruptive accident has been a major issue in post accident heat removal studies. One characteristic feature of this problem is that the solid substrate, when molten, is miscible with and lighter than the core melt so that the rate of penetration is strongly dependent upon the motion of natural convection in the melt layer driven by the density difference between the core melt and the molten substrate. This fundamentally interesting and technologically important problem has been investigated by a number of researchers. Significantly different melting rates, however, were observed in these studies. Questions concerning the occurrence of flow transition and its effect on melt penetration remain to be answered. To promote the understanding of the phenomena and to strengthen the data base of melt penetration, simulation experiments were conducted using various kinds of salt solutions (KI, NaCl, CaCl 2 , and MgCl 2 solutions) as the working fluid and an air-bubble-free ice slab as the solid substrate

Downward Migration of Coastal Conifers as a Response to Recent Land Emergence in Eastern Hudson Bay, Québec

Science.gov (United States)

Bégin, Yves; Bérubé, Dominique; Grégoire, Martin

1993-07-01

Postglacial uplift in the eastern Hudson Bay area is among the most rapid in the world (300 m during the last 8000 yr). Although emergence curves based on 14 C-dated raised shorelines give a consistent basis for modeling relative sea-level changes, such a low-resolution dating method is inappropriate for estimating trends over recent decades. A major downward displacement of white spruce ( Picea glauca (Moench) Voss) and tamarack ( Larix laricina (DuRoi) K. Koch) occurred on protected shores as a response to shoreline retreat during this century. Analysis of the age distribution of trees indicates a progradation of white spruce and tamarack on gently sloping terrain ranging from 1.3 and 2.6 cm/yr, respectively, toward the sea. Improvement of climatic conditions during the 20th century favored such expansion which was probably faster than the real land emergence rates, but recent episodes of high water levels caused regression of forest margins over the highly exposed shores. Nevertheless, the downward trend of the treeline over this century substantiates the projections of 14C-dated coastal emergence curves during the modern period (1.0 to 1.3 cm/yr) by providing an estimate of the maximum rates of shoreline retreat.

Redatuming borehole-to-surface electromagnetic data using Stratton-Chu integral transforms

DEFF Research Database (Denmark)

Zhdanov, Michael; Cai, Hongzhu

2012-01-01

We present a new method of analyzing borehole-to-surface electromagnetic (BSEM) survey data based on redatuming of the observed data from receivers distributed over the surface of the earth onto virtual receivers located within the subsurface. The virtual receivers can be placed close to the target...... of interest, such as just above a hydrocarbon reservoir, which increases the sensitivity of the EM data to the target. The method is based on the principles of downward analytical continuation of EM fields. We use Stratton-Chu type integral transforms to calculate the EM fields at the virtual receivers. Model...

Evaluation and comparison of the processing methods of airborne gravimetry concerning the errors effects on downward continuation results: Case studies in Louisiana (USA) and the Tibetan Plateau (China)

DEFF Research Database (Denmark)

Zhao, Qilong; Strykowski, Gabriel; Li, Jiancheng

2017-01-01

and the most extreme area of the world for this type of survey is the Tibetan Plateau. Since there are no high-accuracy surface gravity data available for this area, the above error minimization method involving the external gravity data cannot be used. We propose a semi-parametric downward continuation method...... in combination with regularization to suppress the systematic error effect and the random error effect in the Tibetan Plateau; i.e., without the use of the external high-accuracy gravity data. We use a Louisiana airborne gravity dataset from the USA National Oceanic and Atmospheric Administration (NOAA......) to demonstrate that the new method works effectively. Furthermore, and for the Tibetan Plateau we show that the numerical experiment is also successfully conducted using the synthetic Earth Gravitational Model 2008 (EGM08)-derived gravity data contaminated with the synthetic errors. The estimated systematic...

Phonon-mediated decay of an atom in a surface-induced potential

International Nuclear Information System (INIS)

Kien, Fam Le; Hakuta, K.; Dutta Gupta, S.

2007-01-01

We study phonon-mediated transitions between translational levels of an atom in a surface-induced potential. We present a general master equation governing the dynamics of the translational states of the atom. In the framework of the Debye model, we derive compact expressions for the rates for both upward and downward transitions. Numerical calculations for the transition rates are performed for a deep silica-induced potential allowing for a large number of bound levels as well as free states of a cesium atom. The total absorption rate is shown to be determined mainly by the bound-to-bound transitions for deep bound levels and by bound-to-free transitions for shallow bound levels. Moreover, the phonon emission and absorption processes can be orders of magnitude larger for deep bound levels as compared to the shallow bound ones. We also study various types of transitions from free states. We show that, for thermal atomic cesium with a temperature in the range from 100 μK to 400 μK in the vicinity of a silica surface with a temperature of 300 K, the adsorption (free-to-bound decay) rate is about two times larger than the heating (free-to-free upward decay) rate, while the cooling (free-to-free downward decay) rate is negligible

a Research on Monitoring Surface Deformation and Relationships with Surface Parameters in Qinghai Tibetan Plateau Permafrost

Science.gov (United States)

Mi, S. J.; Li, Y. T.; Wang, F.; Li, L.; Ge, Y.; Luo, L.; Zhang, C. L.; Chen, J. B.

2017-09-01

different in arid areas and wet areas. During the research time, frost heaving firstly accounted for a large proportion both in the arid and wet areas with the decrease of downward radiation from July to December; after December, thaw settlement came into prominence with the increase downward radiation in the arid areas, while in the wet areas, surface put into diverse situations because of water transformation leading to severe deformation. In summary, soil moisture is an important factor that influences the surface deformation. This relationship between deformation process and soil moisture will be researched more in our further work.

Surface correlations of hydrodynamic drag for transitionally rough engineering surfaces

Science.gov (United States)

Thakkar, Manan; Busse, Angela; Sandham, Neil

2017-02-01

Rough surfaces are usually characterised by a single equivalent sand-grain roughness height scale that typically needs to be determined from laboratory experiments. Recently, this method has been complemented by a direct numerical simulation approach, whereby representative surfaces can be scanned and the roughness effects computed over a range of Reynolds number. This development raises the prospect over the coming years of having enough data for different types of rough surfaces to be able to relate surface characteristics to roughness effects, such as the roughness function that quantifies the downward displacement of the logarithmic law of the wall. In the present contribution, we use simulation data for 17 irregular surfaces at the same friction Reynolds number, for which they are in the transitionally rough regime. All surfaces are scaled to the same physical roughness height. Mean streamwise velocity profiles show a wide range of roughness function values, while the velocity defect profiles show a good collapse. Profile peaks of the turbulent kinetic energy also vary depending on the surface. We then consider which surface properties are important and how new properties can be incorporated into an empirical model, the accuracy of which can then be tested. Optimised models with several roughness parameters are systematically developed for the roughness function and profile peak turbulent kinetic energy. In determining the roughness function, besides the known parameters of solidity (or frontal area ratio) and skewness, it is shown that the streamwise correlation length and the root-mean-square roughness height are also significant. The peak turbulent kinetic energy is determined by the skewness and root-mean-square roughness height, along with the mean forward-facing surface angle and spanwise effective slope. The results suggest feasibility of relating rough-wall flow properties (throughout the range from hydrodynamically smooth to fully rough) to surface

Table for monthly average daily extraterrestrial irradiation on horizontal surface and the maximum possible sunshine duration

International Nuclear Information System (INIS)

Jain, P.C.

1984-01-01

The monthly average daily values of the extraterrestrial irradiation on a horizontal surface (H 0 ) and the maximum possible sunshine duration are two important parameters that are frequently needed in various solar energy applications. These are generally calculated by scientists each time they are needed and by using the approximate short-cut methods. Computations for these values have been made once and for all for latitude values of 60 deg. N to 60 deg. S at intervals of 1 deg. and are presented in a convenient tabular form. Values of the maximum possible sunshine duration as recorded on a Campbell Stoke's sunshine recorder are also computed and presented. These tables should avoid the need for repetition and approximate calculations and serve as a useful ready reference for solar energy scientists and engineers. (author)

Symmetric scaling properties in global surface air temperature anomalies

Science.gov (United States)

Varotsos, Costas A.; Efstathiou, Maria N.

2015-08-01

We have recently suggested "long-term memory" or internal long-range correlation within the time-series of land-surface air temperature (LSAT) anomalies in both hemispheres. For example, an increasing trend in the LSAT anomalies is followed by another one at a different time in a power-law fashion. However, our previous research was mainly focused on the overall long-term persistence, while in the present study, the upward and downward scaling dynamics of the LSAT anomalies are analysed, separately. Our results show that no significant fluctuation differences were found between the increments and decrements in LSAT anomalies, over the whole Earth and over each hemisphere, individually. On the contrary, the combination of land-surface air and sea-surface water temperature anomalies seemed to cause a departure from symmetry and the increments in the land and sea surface temperature anomalies appear to be more persistent than the decrements.

A stable downward continuation of airborne magnetic data: A case study for mineral prospectivity mapping in Central Iran

Science.gov (United States)

Abedi, Maysam; Gholami, Ali; Norouzi, Gholam-Hossain

2013-03-01

Previous studies have shown that a well-known multi-criteria decision making (MCDM) technique called Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE II) to explore porphyry copper deposits can prioritize the ground-based exploratory evidential layers effectively. In this paper, the PROMETHEE II method is applied to airborne geophysical (potassium radiometry and magnetometry) data, geological layers (fault and host rock zones), and various extracted alteration layers from remote sensing images. The central Iranian volcanic-sedimentary belt is chosen for this study. A stable downward continuation method as an inverse problem in the Fourier domain using Tikhonov and edge-preserving regularizations is proposed to enhance magnetic data. Numerical analysis of synthetic models show that the reconstructed magnetic data at the ground surface exhibits significant enhancement compared to the airborne data. The reduced-to-pole (RTP) and the analytic signal filters are applied to the magnetic data to show better maps of the magnetic anomalies. Four remote sensing evidential layers including argillic, phyllic, propylitic and hydroxyl alterations are extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images in order to map the altered areas associated with porphyry copper deposits. Principal component analysis (PCA) based on six Enhanced Thematic Mapper Plus (ETM+) images is implemented to map iron oxide layer. The final mineral prospectivity map based on desired geo-data set indicates adequately matching of high potential zones with previous working mines and copper deposits.

Impact of East Asian Summer Monsoon on Surface Ozone Pattern in China

Science.gov (United States)

Li, Shu; Wang, Tijian; Huang, Xing; Pu, Xi; Li, Mengmeng; Chen, Pulong; Yang, Xiu-Qun; Wang, Minghuai

2018-01-01

Tropospheric ozone plays a key role in regional and global atmospheric and climate systems. In East Asia, ozone can be affected both in concentration level and spatial pattern by typical monsoon climate. This paper uses three different indices to identify the strength of East Asian summer monsoon (EASM) and explores the possible impact of EASM intensity on the ozone pattern through synthetic and process analysis. The difference in ozone between three strong and three weak monsoon years was analyzed using the simulations from regional climate model RegCM4-Chem. It was found that EASM intensity can significantly influence the spatial distribution of ozone in the lower troposphere. When EASM is strong, ozone in the eastern part of China (28°N - 42° N) is reduced, but the inverse is detected in the north and south. The surface ozone difference ranges from -7 to 7 ppbv during the 3 months (June to August) of the EASM, with the most obvious difference in August. Difference of the 3 months' average ozone ranges from -3.5 to 4 ppbv. Process analysis shows that the uppermost factor controlling ozone level during summer monsoon seasons is the chemistry process. Interannual variability of EASM can impact the spatial distribution of ozone through wind in the lower troposphere, cloud cover, and downward shortwave radiation, which affect the transport and chemical formation of ozone. The phenomenon should be addressed when considering the interaction between ozone and the climate in East Asia region.

The Plumbing of Land Surface Models: Is Poor Performance a Result of Methodology or Data Quality?

Science.gov (United States)

Haughton, Ned; Abramowitz, Gab; Pitman, Andy J.; Or, Dani; Best, Martin J.; Johnson, Helen R.; Balsamo, Gianpaolo; Boone, Aaron; Cuntz, Matthais; Decharme, Bertrand;

Role of sea surface temperature anomalies in the tropical Indo-Pacific region in the northeast Asia severe drought in summer 2014: month-to-month perspective

Science.gov (United States)

Xu, Zhiqing; Fan, Ke; Wang, HuiJun

2017-09-01

The severe drought over northeast Asia in summer 2014 and the contribution to it by sea surface temperature (SST) anomalies in the tropical Indo-Pacific region were investigated from the month-to-month perspective. The severe drought was accompanied by weak lower-level summer monsoon flow and featured an obvious northward movement during summer. The mid-latitude Asian summer (MAS) pattern and East Asia/Pacific teleconnection (EAP) pattern, induced by the Indian summer monsoon (ISM) and western North Pacific summer monsoon (WNPSM) rainfall anomalies respectively, were two main bridges between the SST anomalies in the tropical Indo-Pacific region and the severe drought. Warming in the Arabian Sea induced reduced rainfall over northeast India and then triggered a negative MAS pattern favoring the severe drought in June 2014. In July 2014, warming in the tropical western North Pacific led to a strong WNPSM and increased rainfall over the Philippine Sea, triggering a positive EAP pattern. The equatorial eastern Pacific and local warming resulted in increased rainfall over the off-equatorial western Pacific and triggered an EAP-like pattern. The EAP pattern and EAP-like pattern contributed to the severe drought in July 2014. A negative Indian Ocean dipole induced an anomalous meridional circulation, and warming in the equatorial eastern Pacific induced an anomalous zonal circulation, in August 2014. The two anomalous cells led to a weak ISM and WNPSM, triggering the negative MAS and EAP patterns responsible for the severe drought. Two possible reasons for the northward movement of the drought were also proposed.

Analysis of energy flow during playground surface impacts.

Science.gov (United States)

Davidson, Peter L; Wilson, Suzanne J; Chalmers, David J; Wilson, Barry D; Eager, David; McIntosh, Andrew S

2013-10-01

The amount of energy dissipated away from or returned to a child falling onto a surface will influence fracture risk but is not considered in current standards for playground impact-attenuating surfaces. A two-mass rheological computer simulation was used to model energy flow within the wrist and surface during hand impact with playground surfaces, and the potential of this approach to provide insights into such impacts and predict injury risk examined. Acceleration data collected on-site from typical playground surfaces and previously obtained data from children performing an exercise involving freefalling with a fully extended arm provided input. The model identified differences in energy flow properties between playground surfaces and two potentially harmful surface characteristics: more energy was absorbed by (work done on) the wrist during both impact and rebound on rubber surfaces than on bark, and rubber surfaces started to rebound (return energy to the wrist) while the upper limb was still moving downward. Energy flow analysis thus provides information on playground surface characteristics and the impact process, and has the potential to identify fracture risks, inform the development of safer impact-attenuating surfaces, and contribute to development of new energy-based arm fracture injury criteria and tests for use in conjunction with current methods.

Impact of soil moisture and winter wheat height from the Loess Plateau in Northwest China on surface spectral albedo

Science.gov (United States)

Li, Zhenchao; Yang, Jiaxi; Gao, Xiaoqing; Zheng, Zhiyuan; Yu, Ye; Hou, Xuhong; Wei, Zhigang

2018-02-01

The understanding of surface spectral radiation and reflected radiation characteristics of different surfaces in different climate zones aids in the interpretation of regional surface energy transfers and the development of land surface models. This study analysed surface spectral radiation variations and corresponding surface albedo characteristics at different wavelengths as well as the relationship between 5-cm soil moisture and surface albedo on typical sunny days during the winter wheat growth period. The analysis was conducted using observational Loess Plateau winter wheat data from 2015. The results show that the ratio of atmospheric downward radiation to global radiation on typical sunny days is highest for near-infrared wavelengths, followed by visible wavelengths and ultraviolet wavelengths, with values of 57.3, 38.7 and 4.0%, respectively. The ratio of reflected spectral radiation to global radiation varies based on land surface type. The visible radiation reflected by vegetated surfaces is far less than that reflected by bare ground, with surface albedos of 0.045 and 0.27, respectively. Thus, vegetated surfaces absorb more visible radiation than bare ground. The atmospheric downward spectral radiation to global radiation diurnal variation ratios vary for near-infrared wavelengths versus visible and ultraviolet wavelengths on typical sunny days. The near-infrared wavelengths ratio is higher in the morning and evening and lower at noon. The visible and ultraviolet wavelengths ratios are lower in the morning and evening and higher at noon. Visible and ultraviolet wavelength surface albedo is affected by 5-cm soil moisture, demonstrating a significant negative correlation. Excluding near-infrared wavelengths, correlations between surface albedo and 5-cm soil moisture pass the 99% confidence test at each wavelength. The correlation with 5-cm soil moisture is more significant at shorter wavelengths. However, this study obtained surface spectral radiation

Clean Os(0001) electronic surface states: A first-principle fully relativistic investigation

Science.gov (United States)

Urru, Andrea; Dal Corso, Andrea

2018-05-01

We analyze the electronic structure of the Os(0001) surface by means of first-principle calculations based on Fully Relativistic (FR) Density Functional Theory (DFT) and a Projector Augmented-Wave (PAW) approach. We investigate surface states and resonances analyzing their spin-orbit induced energy splitting and their spin polarization. The results are compared with previously studied surfaces Ir(111), Pt(111), and Au(111). We do not find any surface state in the gap similar to the L-gap of the (111) fcc surfaces, but find Rashba split resonances that cross the Fermi level and, as in the recently studied Ir(111) surface, have a characteristic downward dispersion. Moreover, for some selected surface states we study the spin polarization with respect to k∥, the wave-vector parallel to the surface. In some cases, such as the Rashba split resonances, the spin polarization shows a smooth behavior with slow rotations, in others the rotation is faster, due to mixing and anti-crossing of the states.

Research on the Flow Field and Structure Optimization in Cyclone Separator with Downward Exhaust Gas

Directory of Open Access Journals (Sweden)

Wang Weiwei

2017-01-01

Full Text Available A numerical software analysis of the turbulent and strongly swirling flow field of a cyclone separator with downward exhaust gas and its performances is described. The ANSYS 14.0 simulations based on DPM model are also used in the investigation. A new set of geometrical design has been optimized to achieve minimum pressure drop and maximum separation efficiency. A comparison of numerical simulation of the new design confirm the superior performance of the new design compared to the conventional design. The influence of the structure parameters such as the length of the guide pipe, the shape of the guide, the inlet shape on the separation performance was analyzed in this research. This research result has certain reference value for cyclone separator design and performance optimization.

Atomic-scale friction on stepped surfaces of ionic crystals.

Science.gov (United States)

Steiner, Pascal; Gnecco, Enrico; Krok, Franciszek; Budzioch, Janusz; Walczak, Lukasz; Konior, Jerzy; Szymonski, Marek; Meyer, Ernst

2011-05-06

We report on high-resolution friction force microscopy on a stepped NaCl(001) surface in ultrahigh vacuum. The measurements were performed on single cleavage step edges. When blunt tips are used, friction is found to increase while scanning both up and down a step edge. With atomically sharp tips, friction still increases upwards, but it decreases and even changes sign downwards. Our observations extend previous results obtained without resolving atomic features and are associated with the competition between the Schwöbel barrier and the asymmetric potential well accompanying the step edges.

Solute transport with time-variable flow paths during upward and downward flux in a heterogeneous unsaturated porous medium

Science.gov (United States)

Cremer, Clemens; Neuweiler, Insa; Bechtold, Michel; Vanderborght, Jan

2014-05-01

To acquire knowledge of solute transport through the unsaturated zone in the shallow subsurface is decisive to assess groundwater quality, nutrient cycling or to plan remediation strategies. The shallow subsurface is characterized by structural heterogeneity and strongly influenced by atmospheric conditions. This leads to changing flow directions, strong temporal changes in saturation and heterogeneous water fluxes during infiltration and evaporation events. Recent studies (e.g. Lehmann and Or, 2009; Bechtold et al.,2011) demonstrated the importance of lateral flow and solute transport during evaporation conditions (upward flux). The heterogeneous structure in these studies was constructed using two types of sand with strong material contrasts and arranged in parallel with a vertical orientation. Lateral transport and redistribution of solute from coarse to fine media was observed deeper in the soil column and from fine to coarse close to the soil surface. However, if boundary conditions are reversed due to precipitation, the flow field is not necessarily reversed in the same manner, resulting in entirely different transport patterns for downward and upward flow. Therefore, considering net-flow rates alone is misleading when describing transport under those conditions. In this contribution we analyze transport of a solute in the shallow subsurface to assess effects resulting from the temporal change of heterogeneous soil structures due to dynamic flow conditions. Two-dimensional numerical simulations of unsaturated flow and transport are conducted using a coupled finite volume and random walk particle tracking algorithm to quantify solute transport and leaching rates. Following previous studies (Lehmann and Or, 2009; Bechtold et al., 2011), the chosen domain is composed of two materials, coarse and fine sand, arranged in parallel with a vertical orientation. Hence, one sharp interface of strong material heterogeneity is induced. During evaporation both sands are

Decadal evolution of the surface energy budget during the fast warming and global warming hiatus periods in the ERA-interim

Science.gov (United States)

Hu, Xiaoming; Sejas, Sergio A.; Cai, Ming; Taylor, Patrick C.; Deng, Yi; Yang, Song

2018-05-01

The global-mean surface temperature has experienced a rapid warming from the 1980s to early-2000s but a muted warming since, referred to as the global warming hiatus in the literature. Decadal changes in deep ocean heat uptake are thought to primarily account for the rapid warming and subsequent slowdown. Here, we examine the role of ocean heat uptake in establishing the fast warming and warming hiatus periods in the ERA-Interim through a decomposition of the global-mean surface energy budget. We find the increase of carbon dioxide alone yields a nearly steady increase of the downward longwave radiation at the surface from the 1980s to the present, but neither accounts for the fast warming nor warming hiatus periods. During the global warming hiatus period, the transfer of latent heat energy from the ocean to atmosphere increases and the total downward radiative energy flux to the surface decreases due to a reduction of solar absorption caused primarily by an increase of clouds. The reduction of radiative energy into the ocean and the surface latent heat flux increase cause the ocean heat uptake to decrease and thus contribute to the slowdown of the global-mean surface warming. Our analysis also finds that in addition to a reduction of deep ocean heat uptake, the fast warming period is also driven by enhanced solar absorption due predominantly to a decrease of clouds and by enhanced longwave absorption mainly attributed to the air temperature feedback.

Characterization of as-grown and adsorbate-covered N-polar InN surfaces using in situ photoelectron spectroscopy

International Nuclear Information System (INIS)

Eisenhardt, Anja; Himmerlich, Marcel; Krischok, Stefan

2012-01-01

The surface electronic properties and adsorption behaviour of as-grown and oxidized N-polar InN films are characterized by photoelectron spectroscopy (XPS, UPS). The epitaxial growth of the InN layers was performed by plasma-assisted molecular beam epitaxy on GaN/6H-SiC(000-1). After growth and in situ characterization the InN surfaces were exposed to molecular oxygen to evaluate the adsorption behaviour of O 2 on N-polar InN and to study its impact on the surface electronic properties of the III-nitride material. The results are compared with studies on In-polar InN on GaN/sapphire templates. The as-grown N-polar InN surface exhibits a pronounced surface state at a binding energy of ∝1.6 eV. The valence band minimum lies about 0.8-1.0 eV below the surface Fermi level. Additionally, the XPS core level binding energies for InN(000-1) are reduced compared to InN(0001) films, indicating different surface band bending for clean N-polar and In-polar InN, respectively. The interaction of molecular oxygen with the InN(000-1) surface leads to a downward band bending by 0.1 eV compared to the initial state. Additional adsorption of species from the residual gas of the UHV chamber increases the surface downward band bending. Furthermore two pronounced oxygen related states with an energy distance of ∝5 eV could be detected in the valence band region. The adsorbed oxygen results in an additional component in the N1s core level spectra, which is interpreted as formation of NO x bonds. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Trends in annual, seasonal, and monthly streamflow characteristics at 227 streamgages in the Missouri River watershed, water years 1960-2011

Science.gov (United States)

Norton, Parker A.; Anderson, Mark T.; Stamm, John F.

2014-01-01

The Missouri River and its tributaries are an important resource that serve multiple uses including agriculture, energy, recreation, and municipal water supply. Understanding historical streamflow characteristics provides relevant guidance to adaptive management of these water resources. Streamflow records in the Missouri River watershed were examined for trends in time series of annual, seasonal, and monthly streamflow. A total of 227 streamgages having continuous observational records for water years 1960–2011 were examined. Kendall’s tau nonparametric test was used to determine statistical significance of trends in annual, seasonal, and monthly streamflow. A trend was considered statistically significant for a probability value less than or equal to 0.10 that the Kendall’s tau value equals zero. Significant trends in annual streamflow were indicated for 101 out of a total of 227 streamgages. The Missouri River watershed was divided into six watershed regions and trends within regions were examined. The western and the southern parts of the Missouri River watershed had downward trends in annual streamflow (56 streamgages), whereas the eastern part of the watershed had upward trends in streamflow (45 streamgages). Seasonal and monthly streamflow trends reflected prevailing annual streamflow trends within each watershed region.

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.

Experimental Study on Downwardly Spreading Flame over Inclined Polyethylene-insulated Electrical Wire with Applied AC Electric Fields

KAUST Repository

Lim, Seung Jae

2014-12-30

An experimental study on downwardly spreading flame over slanted electrical wire, which is insulated by Polyethylene (PE), was conducted with applied AC electric fields. The result showed that the flame spread rate decreased initially with increase in inclination angle of wire and then became nearly constant. The flame shape was modified significantly with applied AC electric field due to the effect of ionic wind. Such a variation in flame spread rate could be explained by a thermal balance mechanism, depending on flame shape and slanted direction of flame. Extinction of the spreading flame was not related to angle of inclination, and was described well by a functional dependency upon the frequency and voltage at extinction.

Observation of low-frequency acoustic surface waves in the nocturnal boundary layer.

Science.gov (United States)

Talmadge, Carrick L; Waxler, Roger; Di, Xiao; Gilbert, Kenneth E; Kulichkov, Sergey

2008-10-01

A natural terrain surface, because of its porosity, can support an acoustic surface wave that is a mechanical analog of the familiar vertically polarized surface wave in AM radio transmission. At frequencies of several hundred hertz, the acoustic surface wave is attenuated over distances of a few hundred meters. At lower frequencies (e.g., below approximately 200 Hz) the attenuation is much less, allowing surface waves to propagate thousands of meters. At night, a low-frequency surface wave is generally present at long ranges even when downward refraction is weak. Thus, surface waves represent a ubiquitous nighttime transmission mode that exists even when other transmission modes are weak or absent. Data from recent nighttime field experiments and theoretical calculations are presented, demonstrating the persistence of the surface wave under different meteorological conditions. The low-frequency surface wave described here is the "quasiharmonical" tail observed previously in nighttime measurements but not identified by S. Kulichkov and his colleagues (Chunchuzov, I. P. et al. 1990. "On acoustical impulse propagation in a moving inhomogeneous atmospheric layer," J. Acoust. Soc. Am. 88, 455-461).

Self-energy behavior away from the Fermi surface in doped Mott insulators.

Science.gov (United States)

Merino, J; Gunnarsson, O; Kotliar, G

2016-02-03

We analyze self-energies of electrons away from the Fermi surface in doped Mott insulators using the dynamical cluster approximation to the Hubbard model. For large onsite repulsion, U, and hole doping, the magnitude of the self-energy for imaginary frequencies at the top of the band ([Formula: see text]) is enhanced with respect to the self-energy magnitude at the bottom of the band ([Formula: see text]). The self-energy behavior at these two [Formula: see text]-points is switched for electron doping. Although the hybridization is much larger for (0, 0) than for [Formula: see text], we demonstrate that this is not the origin of this difference. Isolated clusters under a downward shift of the chemical potential, [Formula: see text], at half-filling reproduce the overall self-energy behavior at (0, 0) and [Formula: see text] found in low hole doped embedded clusters. This happens although there is no change in the electronic structure of the isolated clusters. Our analysis shows that a downward shift of the chemical potential which weakly hole dopes the Mott insulator can lead to a large enhancement of the [Formula: see text] self-energy for imaginary frequencies which is not associated with electronic correlation effects, even in embedded clusters. Interpretations of the strength of electronic correlations based on self-energies for imaginary frequencies are, in general, misleading for states away from the Fermi surface.

Uncertainty in RELAP5/MOD3.2 calculations for interfacial drag in downward two-phase flow

International Nuclear Information System (INIS)

Clark, Collin; Schlegel, Joshua P.; Hibiki, Takashi; Ishii, Mamoru; Kinoshita, Ikuo

2016-01-01

Highlights: • Uncertainty propagation is key for best estimate code reliability. • Uncertainty in drift flux correlations used to evaluate uncertainty in interfacial drag. • Bias and error have been compared for various models. - Abstract: RELAP5/MOD3.2 is a thermal-hydraulic system analysis code used to predict the response of nuclear reactor coolant systems in the event of certain accident scenarios. It is important that RELAP and other system analysis codes are able to accurately predict various two-phase flow phenomena, particularly the interfacial transfers between the liquid and gas phases. It is also important to understand how much uncertainty exists in these predictions due to uncertainties in the constitutive relations used to close the two-fluid model. In this paper, the uncertainty in the interfacial drag calculated by RELAP5/MOD3.2 due to errors in the drift-flux models used to close the model is evaluated and compared to the correlation developed by Goda et al. (2003). The case of downward flow is considered due to the importance of co-current and counter-current downward flow for predicting behavior in the downcomer of reactor systems during small-break Loss of Coolant Accidents (LOCAs) in nuclear reactor systems. The overall uncertainty in the interfacial force calculations due to error in the distribution parameter models were found to have a bias of +8.1% and error of 20.1% for the models used in RELAP5, and a bias of −30.8% and error of 23.1% for the correlation of Goda et al. (2003). However this analysis neglects the effects of compensating errors in the drift-flux parameters, as the drift velocity is assumed to be perfectly accurate. More physically meaningful results could be obtained if the distribution parameter and drift velocity were calculated directly from local phase concentration and velocity measurements, however no studies were available which included all of this information.

Monthly Rainfall Erosivity Assessment for Switzerland

Science.gov (United States)

Schmidt, Simon; Meusburger, Katrin; Alewell, Christine

2016-04-01

Water erosion is crucially controlled by rainfall erosivity, which is quantified out of the kinetic energy of raindrop impact and associated surface runoff. Rainfall erosivity is often expressed as the R-factor in soil erosion risk models like the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). Just like precipitation, the rainfall erosivity of Switzerland has a characteristic seasonal dynamic throughout the year. This inter-annual variability is to be assessed by a monthly and seasonal modelling approach. We used a network of 86 precipitation gauging stations with a 10-minute temporal resolution to calculate long-term average monthly R-factors. Stepwise regression and Monte Carlo Cross Validation (MCCV) was used to select spatial covariates to explain the spatial pattern of R-factor for each month across Switzerland. The regionalized monthly R-factor is mapped by its individual regression equation and the ordinary kriging interpolation of its residuals (Regression-Kriging). As covariates, a variety of precipitation indicator data has been included like snow height, a combination of hourly gauging measurements and radar observations (CombiPrecip), mean monthly alpine precipitation (EURO4M-APGD) and monthly precipitation sums (Rhires). Topographic parameters were also significant explanatory variables for single months. The comparison of all 12 monthly rainfall erosivity maps showed seasonality with highest rainfall erosivity in summer (June, July, and August) and lowest rainfall erosivity in winter months. Besides the inter-annual temporal regime, a seasonal spatial variability was detectable. Spatial maps of monthly rainfall erosivity are presented for the first time for Switzerland. The assessment of the spatial and temporal dynamic behaviour of the R-factor is valuable for the identification of more susceptible seasons and regions as well as for the application of selective erosion control measures. A combination with monthly vegetation

Six-month storage-time evaluation of one-bottle adhesive systems to dentin.

Science.gov (United States)

Giannini, Marcelo; Seixas, Carla Alessandra Marcelino; Reis, Andre Figueiredo; Pimenta, Luiz André Freire

2003-01-01

The goal of this study was to evaluate the 1-week, 3-month, and 6-month performance of eight commercially available one-bottle adhesive systems to dentin. Lingual and buccal surfaces from human third molars were ground wet on 600-grit SiC paper to obtain a flat dentinal surface. The specimens were randomly divided into 24 groups (n = 10), which were established to measure the shear bond strengths of Bond-1 (B1), ONE-STEP (OS), OptiBond SOLO (OP), Prime & Bond 2.1 (PB), Single Bond (SB), STAE (ST), Syntac Sprint (SS), and Tenure Quick (TQ) after 1-week, 3-month, and 6-month water storage at 37 degrees C. One-bottle adhesives were applied according to manufacturers' instructions and Z100 composite cylinders were applied on the bonded dentinal surfaces. The 3-month water-storage groups were thermocycled for 1500 cycles at 5 degrees C and 55 degrees C and 6-month groups for 3000 cycles. After storage periods, specimens were tested in shear in a universal testing machine (0.5 mm/min). were statistically analyzed by analysis of variance and Tukey test. Results: The changes in shear bond strengths were not uniform over time. Over the test period, OS, PB, SB, and SS exhibited bond strength stability, however, SS presented low bond strengths on all tested periods. A significant decrease in bond strength was observed for B1, OP, ST, and TQ after the 6-month storage period.

GEWEX Surface Radiation Budget (SRB)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NASA/GEWEX Surface Radiation Budget (SRB) Release-3.0 data sets contains global 3-hourly, daily, monthly/3-hourly, and monthly averages of surface and top-of...

Mixed convection-radiation interaction in boundary-layer flow over horizontal surfaces

Science.gov (United States)

Ibrahim, F. S.; Hady, F. M.

1990-06-01

The effect of buoyancy forces and thermal radiation on the steady laminar plane flow over an isothermal horizontal flat plate is investigated within the framework of first-order boundary-layer theory, taking into account the hydrostatic pressure variation normal to the plate. The fluid considered is a gray, absorbing-emitting but nonscattering medium, and the Rosseland approximation is used to describe the radiative heat flux in the energy equation. Both a hot surface facing upward and a cold surface facing downward are considered in the analysis. Numerical results for the local Nusselt number, the local wall shear stress, the local surface heat flux, as well as the velocity and temperature distributions are presented for gases with a Prandtl number of 0.7 for various values of the radiation-conduction parameter, the buoyancy parameter, and the temperature ratio parameter.

LBA Regional Monthly Climatology for the 20th Century (New et al.)

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set is a subset of "Global Monthly Climatology for the 20th Century (New et al.)" (2000a). This subset characterizes mean monthly surface climate...

Time and spatial heat transfer performance around an isothermally heated sphere placed in a uniform, downwardly directed flow (in relation to the enhancement of latent heat storage rate in a spherical capsule)

International Nuclear Information System (INIS)

Koizumi, H.

2004-01-01

The aim of this study is to reveal the temporal and spatial heat transfer performance of an isothermally heated sphere placed in a uniform, downwardly directed flow using a micro-foil heat flow sensor (HFS). A HFS, whose response time is about 0.02 s, was pasted on the surface of a heated copper sphere. Experiments were carried out using air with a Grashof number of 3.3 x 10 5 and with several Reynolds numbers (Re) up to 1800. Three flow patterns appeared: a chaotic flow at Re<240; a two-dimensional steady separated flow at 240 ≤ Re<500, and a three-dimensional unsteady separated flow at Re ≥ 500. In addition, the instantaneous and time-averaged heat transfer performance around the sphere in each of the three regions was clarified. Next, enhancement of the latent heat storage rate of a solid phase change material (PCM) in a spherical capsule was performed. The flow around the spherical capsule, in which the solid PCM was filled and placed in a heated, upwardly directed flow, is the approximate adverse flow phenomenon around the heated sphere which was placed in a downwardly directed flow. In other words, the buoyant flow and the forced flow are in the opposite directions in these two cases. Tests of latent heat storage were run for two Reynolds numbers which represented different flow characteristics in the heat transfer experiments, Re=150 and 1800. Furthermore, copper plates were inserted into the solid PCM, of which thermal conductivity was considerably low, to enhance the latent heat storage rate for the two Reynolds number flows

Ground-Based Observations of Terrestrial Gamma Ray Flashes Associated with Downward-Directed Lightning Leaders

Science.gov (United States)

Belz, J.; Abbasi, R.; Krehbiel, P. R.; LeVon, R.; Remington, J.; Rison, W.; Thomas, R. J.

2017-12-01

Terrestrial Gamma Flashes (TGFs) have been observed in satellite-borne gamma ray detectors for several decades, starting with the BATSE instrument on the Compton Gamma-Ray observatory in 1994. TGFs consist of bursts of upwards of 1018 primary gamma rays, with a duration of up to a few milliseconds, originating in the Earth's atmosphere. More recent observations have shown that satellite-observed TGFs are generated in upward-propagating negative leaders of intracloud lightning, suggesting that they may be sensitive to the processes responsible for the initial lightning breakdown. Here, we present the first evidence that TGFs are also produced at the beginning of negative cloud-to-ground flashes, and that they may provide a new window through which ground-based observatories may contribute to understanding the breakdown process. The Telescope Array Surface Detector (TASD) is a 700 square kilometer cosmic ray observatory, an array of 507 3m2 scintillators on a 1.2 km grid. The array is triggered and read out when at least three adjacent detectors observe activity within an 8 μs window. Following the observation of bursts of anomalous TASD triggers, lasting a few hundred microseconds and correlated with local lightning activity, a Lightning Mapping Array (LMA) and slow electric field antenna were installed at the TASD site in order to study the effect. From data obtained between 2014 and 2016, correlated observations were obtained for ten -CG flashes. In 9 out of 10 cases, bursts of up to five anomalous triggers were detected during the first ms of the flash, as negative breakdown was descending into lower positive storm charge. The triggers occurred when the LMA-detected VHF radiation sources were at altitudes between 1.5 to 4.5 km AGL. The tenth flash was initiated by an unusually energetic leader that reached the ground in 2.5 ms and produced increasingly powerful triggers down to about 500 m AGL. While the TASD is not optimized for individual gamma ray detection

LBA Regional Monthly Climatology for the 20th Century (New et al.)

Data.gov (United States)

National Aeronautics and Space Administration — This data set is a subset of "Global Monthly Climatology for the 20th Century (New et al.)" (2000a). This subset characterizes mean monthly surface climate over the...

Description of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

International Nuclear Information System (INIS)

Johansson, Per-Olof

2008-12-01

This report describes the modelling of the surface hydrology and near-surface hydrogeology that was performed for the final site descriptive model of Forsmark produced in the site investigation stage, SDM-Site Forsmark. The comprehensive investigation and monitoring programme forms a strong basis for the developed conceptual and descriptive model of the hydrological and near-surface hydrological system of the site investigation area. However, there are some remaining uncertainties regarding the interaction of deep and near-surface groundwater and surface water of importance for the understanding of the system: The groundwaters in till below Lake Eckarfjaerden, Lake Gaellbotraesket, Lake Fiskarfjaerden and Lake Bolundsfjaerden have high salinities. The hydrological and hydrochemical interpretations indicate that these waters are relict waters of mainly marine origin. From the perspective of the overall water balance, the water below the central parts of the lakes can be considered as stagnant. However, according to the hydrochemical interpretation, these waters also contain weak signatures of deep saline water. Rough chloride budget calculations for the Gaellbotraesket depression also raise the question of a possible upward flow of deep groundwater. No absolute conclusion can be drawn from the existing data analyses regarding the key question of whether there is a small ongoing upward flow of deep saline water. However, Lake Bolundsfjaerden is an exception where the clear downward flow gradient from the till to the bedrock excludes the possibility of an active deep saline source. The available data indicate that there are no discharge areas for flow systems involving deep bedrock groundwater in the northern part of the tectonic lens, where the repository is planned to be located (the so-called 'target area'). However, it can not be excluded that such discharge areas exist. Data indicate that the prevailing downward vertical flow gradients from the QD to the bedrock

Description of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

Energy Technology Data Exchange (ETDEWEB)

Johansson, Per-Olof (Artesia Grundvattenkonsult AB, Taeby (Sweden))

2008-12-15

This report describes the modelling of the surface hydrology and near-surface hydrogeology that was performed for the final site descriptive model of Forsmark produced in the site investigation stage, SDM-Site Forsmark. The comprehensive investigation and monitoring programme forms a strong basis for the developed conceptual and descriptive model of the hydrological and near-surface hydrological system of the site investigation area. However, there are some remaining uncertainties regarding the interaction of deep and near-surface groundwater and surface water of importance for the understanding of the system: The groundwaters in till below Lake Eckarfjaerden, Lake Gaellbotraesket, Lake Fiskarfjaerden and Lake Bolundsfjaerden have high salinities. The hydrological and hydrochemical interpretations indicate that these waters are relict waters of mainly marine origin. From the perspective of the overall water balance, the water below the central parts of the lakes can be considered as stagnant. However, according to the hydrochemical interpretation, these waters also contain weak signatures of deep saline water. Rough chloride budget calculations for the Gaellbotraesket depression also raise the question of a possible upward flow of deep groundwater. No absolute conclusion can be drawn from the existing data analyses regarding the key question of whether there is a small ongoing upward flow of deep saline water. However, Lake Bolundsfjaerden is an exception where the clear downward flow gradient from the till to the bedrock excludes the possibility of an active deep saline source. The available data indicate that there are no discharge areas for flow systems involving deep bedrock groundwater in the northern part of the tectonic lens, where the repository is planned to be located (the so-called 'target area'). However, it can not be excluded that such discharge areas exist. Data indicate that the prevailing downward vertical flow gradients from the QD to

tavgM_2d_ocn_Nx: MERRA 2D IAU Ocean Surface Diagnostic, Monthly Mean 0.667 x 0.5 degree V5.2.0 (MATMNXOCN) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The MATMNXOCN or tavgM_2d_ocn_Nx data product is the MERRA Data Assimilation System 2-Dimensional ocean surface single-level diagnostics that is monthly mean...

Estimation of annual heat flux balance at the sea surface from sst (NOAA-satellite and ships drift data off southeast Brazil

Directory of Open Access Journals (Sweden)

Yoshimine Ikeda

1985-01-01

Full Text Available The objective of this work is to study the possibility of estimating the heat flux balance at the sea surface from GOSSTCOMP (Global Ocean Sea Surface Temperature Computation developed by NOAA/NESS, USA, and sea surface current data based from ships drift information obtained from Pilot Charts, published by the Diretoria de Hidrografia e Navegação (DHN, Brazilian Navy. The annual mean value of the heat flux balance at the sea surface off southeast Brazil for 1977, is estimated from data on the balance between the heat transported by the currents and that transported by eddy diffusion for each volume defined as 2º x 2º (Lat. x Long. square with a constant depth equivalent to an oceanic mixed layer, 100 m thick. Results show several oceanic areas where there are net flows of heat from atmosphere towards the sea surface. In front of Rio de Janeiro the heat flow was downward and up to 70 ly day-1 and is probably related to the upwellirug phenomenon normally occurring in that area. Another coastal area between Lat. 25ºS to 28ºS indicated an downward flow up to 50 ly day-1; and for an area south of Lat. 27ºS, Long. 040ºW - 048ºW an downward flow up to 200 ly day-1, where the transfer was probably due to the cold water of a nortward flux from the Falkland (Malvinas Current. Results also show several oceanic areas where net flows of heat (of about -100 ly day-1 were toward the atmosphere. In the oceanic areas Lat. 19ºS - 23ºS and Lat. 24ºS - 30ºS, the flows were probably due to the warm water of a southward flux of the Brazil Current. The resulting fluxes from the warm waters of the Brazil Current when compared with those from warm waters of the Gulf Stream and Kuroshio, indicate that the Gulf Stream carries about 3.3 times and the Kuroshio 1.7 times more heat than the Brazil Current. These values agree with those of data available on the heat fluxes of the above mentioned Currents calculated by different methods (Budyko, 1974.

Urban surface energy fluxes based on remotely-sensed data and micrometeorological measurements over the Kansai area, Japan

Science.gov (United States)

Sukeyasu, T.; Ueyama, M.; Ando, T.; Kosugi, Y.; Kominami, Y.

2017-12-01

The urban heat island is associated with land cover changes and increases in anthropogenic heat fluxes. Clear understanding of the surface energy budget at urban area is the most important for evaluating the urban heat island. In this study, we develop a model based on remotely-sensed data for the Kansai area in Japan and clarify temporal transitions and spatial distributions of the surface energy flux from 2000 to 2016. The model calculated the surface energy fluxes based on various satellite and GIS products. The model used land surface temperature, surface emissivity, air temperature, albedo, downward shortwave radiation and land cover/use type from the moderate resolution imaging spectroradiometer (MODIS) under cloud free skies from 2000 to 2016 over the Kansai area in Japan (34 to 35 ° N, 135 to 136 ° E). Net radiation was estimated by a radiation budget of upward/downward shortwave and longwave radiation. Sensible heat flux was estimated by a bulk aerodynamic method. Anthropogenic heat flux was estimated by the inventory data. Latent heat flux was examined with residues of the energy budget and parameterization of bulk transfer coefficients. We validated the model using observed fluxes from five eddy-covariance measurement sites: three urban sites and two forested sites. The estimated net radiation roughly agreed with the observations, but the sensible heat flux were underestimated. Based on the modeled spatial distributions of the fluxes, the daytime net radiation in the forested area was larger than those in the urban area, owing to higher albedo and land surface temperatures in the urban area than the forested area. The estimated anthropogenic heat flux was high in the summer and winter periods due to increases in energy-requirements.

An analytical model for displacement velocity of liquid film on a hot vertical surface

International Nuclear Information System (INIS)

Yoshioka, Keisuke; Hasegawa, Shu

1975-01-01

The downward progress of the advancing front of a liquid film streaming down a heated vertical surface, as it would occur in emergency core cooling, is much slower than in the case of ordinary streaming down along a heated surface already wetted with the liquid. A two-dimensional heat conduction model is developed for evaluating this velocity of the liquid front, which takes account of the heat removal by ordinary flow boiling mechanism. In the analysis, the maximum heat flux and the calefaction temperature are taken up as parameters in addition to the initial dry heated wall temperature, the flow rate and the velocity of downward progress of the liquid front. The temperature profile is calculated for various combinations of these parameters. Two criteria are proposed for choosing the most suitable combination of the parameters. One is to reject solutions that represent an oscillating wall temperature distribution, and the second criterion requires that the length of the zone of violent boiling immediately following the liquid front should not be longer than about 1 mm, this value being determined from comparisons made between experiment and calculation. Application of the above two criteria resulted in reasonable values obtained for the calefaction temperature and the maximum heat flux, and the velocity of the liquid front derived therefrom showed good agreement with experiment. (auth.)

Water Entry and Exit of Horizontal Cylinder in Free Surface Flow

International Nuclear Information System (INIS)

Hafsia, Zouhaier; Maalel, Khlifa; Mnasri, Chokri; Mohamed, Omri

2009-01-01

This paper describes two-dimensional numerical simulations of the water entry and exit of horizontal circular cylinder at constant velocity. The deformation of free surface is described by Navier-Stokes (N S) equations of incompressible and viscous fluid with additional transport equation of the volume-of-fluid (VOF). The motion of the cylinder is modeled by the associated momentum source term implemented in the Phoenicis (Parabolic Hyperbolic Or Elliptic Numerical Integration Code Series) code. The domain is discretized by a fixed Cartesian grid using a finite volume method and the cylinder is represented and cut cell method. The simulated results are compared with the numerical results of Lin (2007). This comparison shows good agreement in terms of free surface evolution for water exit and sinking. However, for water entry, the jet flow simulated by Lin is not reproduced. The free surface deformation around the cylinder in downward direction is accurately predicted

A simulation model of distributions of radiational flux at leaf surfaces in crowns of fruit trees

International Nuclear Information System (INIS)

Yamamoto, T.

1988-01-01

A computer-model was constructed for estimating distributions with time of radiational fluxes at leaf surfaces throughout fruit tree canopies in which leaves did not distribute uniformely in three dimensional space. Several assumptions were set up to construct the model for approximation of using solid geometry. For irregular distribution of leaf area in three dimensional space data were used in the simulation as number of leaves per internal cubic bloc of a cubic grid (n-divided per side). Several main parameters used were peculiar to fruit species which contain parameters (λ, ν) of Beta function to calculate both probability density function of leaf area distribution with respect to inclination angle and leaf extinction coefficient for parallel beam by leaves parameters (A, R i ) to calculate stem extinction coefficient for parallel beam, and parameters (D i ) to calculate leaf extinction coefficient of downward transmission and downward reflection. With these data and parameters solid geometry and Lambert-Beer's law constituted this model

Simultaneous emissions of X-rays and microwaves from long laboratory sparks and downward lightning leaders

Science.gov (United States)

Montanya, J.; Oscar, V. D. V.; Tapia, F. F.

2017-12-01

radiation was detected before the return stroke. The microwave emissions in the first positive leader had lower amplitude but presented longer duration whereas the emissions in the three negative downward dart leaders were more impulsive. X-rays were detected in two of the three negative downward dart leaders.

Kaguya observations of the lunar wake in the terrestrial foreshock: Surface potential change by bow-shock reflected ions

Science.gov (United States)

Nishino, Masaki N.; Harada, Yuki; Saito, Yoshifumi; Tsunakawa, Hideo; Takahashi, Futoshi; Yokota, Shoichiro; Matsushima, Masaki; Shibuya, Hidetoshi; Shimizu, Hisayoshi

2017-09-01

There forms a tenuous region called the wake behind the Moon in the solar wind, and plasma entry/refilling into the wake is a fundamental problem of the lunar plasma science. High-energy ions and electrons in the foreshock of the Earth's magnetosphere were detected at the lunar surface in the Apollo era, but their effects on the lunar night-side environment have never been studied. Here we show the first observation of bow-shock reflected protons by Kaguya (SELENE) spacecraft in orbit around the Moon, confirming that solar wind plasma reflected at the terrestrial bow shock can easily access the deepest lunar wake when the Moon stays in the foreshock (We name this mechanism 'type-3 entry'). In a continuous type-3 event, low-energy electron beams from the lunar night-side surface are not obvious even though the spacecraft location is magnetically connected to the lunar surface. On the other hand, in an intermittent type-3 entry event, the kinetic energy of upward-going field-aligned electron beams decreases from ∼ 80 eV to ∼ 20 eV or electron beams disappear as the bow-shock reflected ions come accompanied by enhanced downward electrons. According to theoretical treatment based on electric current balance at the lunar surface including secondary electron emission by incident electron and ion impact, we deduce that incident ions would be accompanied by a few to several times higher flux of an incident electron flux, which well fits observed downward fluxes. We conclude that impact by the bow-shock reflected ions and electrons raises the electrostatic potential of the lunar night-side surface.

Impact of potassium and water on the electronic properties of InN(0001) surfaces

International Nuclear Information System (INIS)

Reiss, S.; Eisenhardt, A.; Krischok, S.; Himmerlich, M.

2014-01-01

In this work we investigate the interaction of potassium and water with 2 x 2 reconstructed InN(0001) surfaces prepared by plasma-assisted molecular beam epitaxy. The influence of adsorbate-substrate-interaction on surface properties is characterized in-situ by photoelectron spectroscopy. Potassium exposure leads to a strong reduction in the work function Φ to 1.6 eV revealing a charge transfer from the adsorbate to the InN surface. In parallel, a reduction of the surface downward band bending by 0.2 eV and hence a reduced electron accumulation density is observed. While interaction of water with clean InN(0001)-2 x 2 surfaces induces only minor changes in the surface band bending, water adsorption at potassium covered InN(0001) leads to a reversal of the K-induced reduction in surface band bending and a slight increase of Φ to 2.4 eV. These results show that surrounding water modifies the interaction of potassium with InN(0001) surfaces. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Development of a methodology for monthly forecasting of surface fires of Colombia's vegetation cover, an application to north Andean region

International Nuclear Information System (INIS)

Gonzalez Hernandez, Yolanda; Rangel CH, Jesus Orlando

2004-01-01

In the present article a methodology is presented for the forecasting of the monthly risk of surface fires of the vegetation cover in Colombia, based on the analysis of meteorological components and variables of climatic and anthropic variability involved in fire risks of the north Andean region. The methodology enables one to regionalize the country, with fire prediction purposes in mind, into ten sub-regions, in each one of which seven height levels are defined to make up separate regions of study. For each of these, a database is built to feed both the logistic regression models and the Poisson models, which identify the variables independent from, and/or associated with the presence or absence of fires

Collector Efficiency in Downward-Type Double-Pass Solar Air Heaters with Attached Fins and Operated by External Recycle

Directory of Open Access Journals (Sweden)

Chii-Dong Ho

2012-07-01

Full Text Available The collector efficiency in a downward-type double-pass external-recycle solar air heater with fins attached on the absorbing plate has been investigated theoretically. Considerable improvement in collector efficiency is obtainable if the collector is equipped with fins and the operation is carried out with an external recycle. Due to the recycling, the desirable effect of increasing the heat transfer coefficient compensates for the undesirable effect of decreasing the driving force (temperature difference of heat transfer, while the attached fins provide an enlarged heat transfer area. The order of performances in the devices of same size is: double pass with recycle and fins > double pass with recycle but without fins > single pass without recycle and fins.

Surface and bulk electronic structures of unintentionally and Mg-doped In0.7Ga0.3N epilayer by hard X-ray photoelectron spectroscopy

Science.gov (United States)

Imura, Masataka; Tsuda, Shunsuke; Takeda, Hiroyuki; Nagata, Takahiro; Banal, Ryan G.; Yoshikawa, Hideki; Yang, AnLi; Yamashita, Yoshiyuki; Kobayashi, Keisuke; Koide, Yasuo; Yamaguchi, Tomohiro; Kaneko, Masamitsu; Uematsu, Nao; Wang, Ke; Araki, Tsutomu; Nanishi, Yasushi

2018-03-01

The surface and bulk electronic structures of In0.7Ga0.3N epilayers are investigated by angle-resolved hard X-ray photoelectron spectroscopy (HX-PES) combined with soft X-PES. The unintentionally and Mg-doped In0.7Ga0.3N (u-In0.7Ga0.3N and In0.7Ga0.3N:Mg, respectively) epilayers are grown by radio-frequency plasma-assisted molecular beam epitaxy. Here three samples with different Mg concentrations ([Mg] = 0, 7 × 1019, and 4 × 1020 cm-3) are chosen for comparison. It is found that a large downward energy band bending exists in all samples due to the formation of a surface electron accumulation (SEA) layer. For u-In0.7Ga0.3N epilayer, band bending as large as 0.8 ± 0.05 eV occurs from bulk to surface. Judged from the valence band spectral edge and numerical analysis of energy band with a surface quantum well, the valence band maximum (VBM) with respect to Fermi energy (EF) level in the bulk is determined to be 1.22 ± 0.05 eV. In contrast, for In0.7Ga0.3N:Mg epilayers, the band bending increases and the VBM only in the bulk tends to shift toward the EF level owing to the Mg acceptor doping. Hence, the energy band is considered to exhibit a downward bending structure due to the coexistence of the n+ SEA layer and Mg-doped p layer formed in the bulk. When [Mg] changes from 7 × 1019 to 4 × 1020 cm-3, the peak split occurs in HX-PES spectra under the bulk sensitive condition. This result indicates that the energy band forms an anomalous downward bending structure with a singular point due to the generation of a thin depleted region at the n+ p interface. For In0.7Ga0.3N:Mg epilayers, the VBM in the bulk is assumed to be slightly lower than EF level within 0.1 eV.

Flow Regime Identification of Co-Current Downward Two-Phase Flow With Neural Network Approach

International Nuclear Information System (INIS)

Hiroshi Goda; Seungjin Kim; Ye Mi; Finch, Joshua P.; Mamoru Ishii; Jennifer Uhle

2002-01-01

Flow regime identification for an adiabatic vertical co-current downward air-water two-phase flow in the 25.4 mm ID and the 50.8 mm ID round tubes was performed by employing an impedance void meter coupled with the neural network classification approach. This approach minimizes the subjective judgment in determining the flow regimes. The signals obtained by an impedance void meter were applied to train the self-organizing neural network to categorize these impedance signals into a certain number of groups. The characteristic parameters set into the neural network classification included the mean, standard deviation and skewness of impedance signals in the present experiment. The classification categories adopted in the present investigation were four widely accepted flow regimes, viz. bubbly, slug, churn-turbulent, and annular flows. These four flow regimes were recognized based upon the conventional flow visualization approach by a high-speed motion analyzer. The resulting flow regime maps classified by the neural network were compared with the results obtained through the flow visualization method, and consequently the efficiency of the neural network classification for flow regime identification was demonstrated. (authors)

A study of the mechanisms causing surface defects on sidewalls during Si etching for TSV (through Si via)

International Nuclear Information System (INIS)

Choi, Jae Woong; Loh, Woon Leng; Praveen, Sampath Kumar; Murphy, Ramana; Swee, Eugene Tan Kiat

2013-01-01

In this paper we report three mechanisms causing surface defects on Si sidewalls during Si etching for TSV. The first mechanism causing surface defects was a downward surface-defect formation due to the participation of the residual polymerizing gas in the transition periods between passivation steps and etch steps. The second mechanism was an upward surface-defect formation due to etchant attacking the interface between the Si and the sidewall polymer. Although the sidewall polymer was thick enough to protect the Si surface, it was not possible to avoid surface defects if the etch step was not switched to the following passivation step in time. The third mechanism was a sponge-like surface-defect formation caused by either poor polymer depositions or voids inside the sidewall polymer. The sponge-like surface defects were formed by Si isotropic etching through the weak points of the sidewall polymer. All three surface defects were considered as the major factors on TSV integration and packaging reliability issues. (paper)

Identification of retinal ganglion cells and their projections involved in central transmission of information about upward and downward image motion.

Directory of Open Access Journals (Sweden)

Keisuke Yonehara

Full Text Available The direction of image motion is coded by direction-selective (DS ganglion cells in the retina. Particularly, the ON DS ganglion cells project their axons specifically to terminal nuclei of the accessory optic system (AOS responsible for optokinetic reflex (OKR. We recently generated a knock-in mouse in which SPIG1 (SPARC-related protein containing immunoglobulin domains 1-expressing cells are visualized with GFP, and found that retinal ganglion cells projecting to the medial terminal nucleus (MTN, the principal nucleus of the AOS, are comprised of SPIG1+ and SPIG1(- ganglion cells distributed in distinct mosaic patterns in the retina. Here we examined light responses of these two subtypes of MTN-projecting cells by targeted electrophysiological recordings. SPIG1+ and SPIG1(- ganglion cells respond preferentially to upward motion and downward motion, respectively, in the visual field. The direction selectivity of SPIG1+ ganglion cells develops normally in dark-reared mice. The MTN neurons are activated by optokinetic stimuli only of the vertical motion as shown by Fos expression analysis. Combination of genetic labeling and conventional retrograde labeling revealed that axons of SPIG1+ and SPIG1(- ganglion cells project to the MTN via different pathways. The axon terminals of the two subtypes are organized into discrete clusters in the MTN. These results suggest that information about upward and downward image motion transmitted by distinct ON DS cells is separately processed in the MTN, if not independently. Our findings provide insights into the neural mechanisms of OKR, how information about the direction of image motion is deciphered by the AOS.

Novel method for the simultaneous estimation of density and surface tension of liquids

International Nuclear Information System (INIS)

Thirunavukkarasu, G.; Srinivasan, G.J.

2003-01-01

The conventional Hare's apparatus generally used for the determination of density of liquids has been modified by replacing its vertical arms (glass tubes) with capillary tubes of 30 cm length and 0.072 cm diameter. When the columns of liquids are drawn through the capillary tubes with reduced pressure at the top of the liquid columns and kept at equilibrium with the atmospheric pressure acting on the liquid surface outside the capillary tubes, the downward pressure due to gravity of the liquid columns has to be coupled with the pressure arising due to the effect of surface tension of the liquids. A fresh expression for the density and surface tension of liquids has been arrived at while equating the pressure balancing system for the two individual liquid columns of the modified Hare's apparatus. The experimental results showed that the proposed method is precise and accurate in the simultaneous estimation of density and surface tension of liquids, with an error of less than 5%

Short-term variations in core surface flow resolved from an improved method of calculating observatory monthly means

DEFF Research Database (Denmark)

Olsen, Nils; Whaler, K. A.; Finlay, Chris

2014-01-01

Monthly means of the magnetic field measurements taken by ground observatories are a useful data source for studying temporal changes of the core magnetic field and the underlying core flow. However, the usual way of calculating monthly means as the arithmetic mean of all days (geomagnetic quiet...... as well as disturbed) and all local times (day and night) may result in contributions from external (magnetospheric and ionospheric) origin in the (ordinary, omm) monthly means. Such contamination makes monthly means less favourable for core studies. We calculated revised monthly means (rmm......), and their uncertainties, from observatory hourly means using robust means and after removal of external field predictions, using an improved method for characterising the magnetospheric ring current. The utility of the new method for calculating observatory monthly means is demonstrated by inverting their first...

Prolonged effect of the stratospheric pathway in linking Barents-Kara Sea sea ice variability to the midlatitude circulation in a simplified model

Science.gov (United States)

Zhang, Pengfei; Wu, Yutian; Smith, Karen L.

2018-01-01

To better understand the dynamical mechanism that accounts for the observed lead-lag correlation between the early winter Barents-Kara Sea (BKS) sea ice variability and the later winter midlatitude circulation response, a series of experiments are conducted using a simplified atmospheric general circulation model with a prescribed idealized near-surface heating over the BKS. A prolonged effect is found in the idealized experiments following the near-surface heating and can be explicitly attributed to the stratospheric pathway and the long time scale in the stratosphere. The analysis of the Eliassen-Palm flux shows that, as a result of the imposed heating and linear constructive interference, anomalous upward propagating planetary-scale waves are excited and weaken the stratospheric polar vortex. This stratospheric response persists for approximately 1-2 months accompanied by downward migration to the troposphere and the surface. This downward migration largely amplifies and extends the low-level jet deceleration in the midlatitudes and cold air advection over central Asia. The idealized model experiments also suggest that the BKS region is the most effective in affecting the midlatitude circulation than other regions over the Arctic.

Flange surface detection device for upper lid of reactor pressure vessel

International Nuclear Information System (INIS)

Kobayashi, Teruo.

1996-01-01

The present invention provide a device for detecting a flatness of an O-ring groove formed on a flange surface simply and at a high accuracy in a state where the upper lid of a reactor pressure vessel is removed as it is. Namely, a running truck provided with magnetic wheels is caused to run while being adsorbed along the outer circumferential surface of a downward flange surface and the lower surface of the flange in a state where the upper lid is removed. A sensor attaching stand equipped with spring-biased wheels is mounted to the running truck. The sensor attaching stand is provided with a flange surface sensor for measuring the distance to the lower surface of the flange and a groove sensor for measuring the distance to the bottom surface of an O-ring groove. Relative displacement of the groove sensor is determined by a calculator based on the measured value on the flange surface sensor. A flatness is obtained from the maximum value and the minimum value. In addition, presence of flaws on the bottom surface of the groove is detected based on the relative change of both measured values at the same time. As a result, all of the errors caused by the running are off-set thereby capable of performing a measurement at high accuracy. (I.S.)

Reliability of levator scapulae index in subjects with and without scapular downward rotation syndrome.

Science.gov (United States)

Lee, Ji-Hyun; Cynn, Heon-Seock; Choi, Woo-Jeong; Jeong, Hyo-Jung; Yoon, Tae-Lim

2016-05-01

The objective of this study was to introduce levator scapulae (LS) measurement using a caliper and the levator scapulae index (LSI) and to investigate intra- and interrater reliability of the LSI in subjects with and without scapular downward rotation syndrome (SDRS). Two raters measured LS length twice in 38 subjects (19 with SDRS and 19 without SDRS). For reliability testing, intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated. Intrarater reliability analysis resulted with ICCs ranging from 0.94 to 0.98 in subjects with SDRS and 0.96 to 0.98 in subjects without SDRS. These results represented that intrarater reliability in both groups were excellent for measuring LS length with the LSI. Interrater reliability was good (ICC: 0.82) in subjects with SDRS; however, interrater reliability was moderate (ICC: 0.75) in subjects without SDRS. Additionally, SEM and MDC were 0.13% and 0.36% in subjects with SDRS and 0.35% and 0.97% in subjects without SDRS. In subjects with SDRS, low dispersion of the measurement errors and MDC were shown. This study suggested that the LSI is a reliable method to measure LS length and is more reliable for subjects with SDRS. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fast simulation tool for ultraviolet radiation at the earth's surface

Science.gov (United States)

Engelsen, Ola; Kylling, Arve

2005-04-01

FastRT is a fast, yet accurate, UV simulation tool that computes downward surface UV doses, UV indices, and irradiances in the spectral range 290 to 400 nm with a resolution as small as 0.05 nm. It computes a full UV spectrum within a few milliseconds on a standard PC, and enables the user to convolve the spectrum with user-defined and built-in spectral response functions including the International Commission on Illumination (CIE) erythemal response function used for UV index calculations. The program accounts for the main radiative input parameters, i.e., instrumental characteristics, solar zenith angle, ozone column, aerosol loading, clouds, surface albedo, and surface altitude. FastRT is based on look-up tables of carefully selected entries of atmospheric transmittances and spherical albedos, and exploits the smoothness of these quantities with respect to atmospheric, surface, geometrical, and spectral parameters. An interactive site, http://nadir.nilu.no/~olaeng/fastrt/fastrt.html, enables the public to run the FastRT program with most input options. This page also contains updated information about FastRT and links to freely downloadable source codes and binaries.

Surface-based test plan, Deaf Smith County, Texas Site: Draft

International Nuclear Information System (INIS)

1985-01-01

The Surface-Based Test Plan (SBTP) is the plan which accounts for all surface-based site field work to be conducted at the Permian salt site selected for characterization. The SBTP relates data needs from program requirement documents and presents plans to satisfy the data needs. The SBTP excludes plans for construction of the Exploratory Shaft Facility (ESF) and plans for the in situ testing. The SBTP is a hierarchical plan stemming from the Technical Program Plan. The SBTP describes in detail the process by which surface-based study plans are defined, developed, and controlled. The plans hierarchy extends downward thru subordinate Site Study Plans (SSPs), which describe in detail elements of field work to be done, to detailed Procedures which document the exact methodologies to be employed in the conduct of field work. The plan is a QA level S document, although some of its elements are at lower QA levels. The plan is a controlled document, and any proposed amendments to the plan or subordinate documents can only be implemented through the specified change control procedure

Monthly SST images of the Stellwagen Bank National Marine Sanctuary

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Grand monthly mean Sea Surface Temperature http://podaac.jpl.nasa.gov/ Naming Convention: XXXX_YYYY1YYYY2_MM_GAVGSST.tif XXXX=location (Stell) YYYY1=start year...

Surface Flux Modeling for Air Quality Applications

Directory of Open Access Journals (Sweden)

Limei Ran

2011-08-01

Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

An experimental study on two-phase pressure drop in small diameter horizontal, downward inclined and vertical tubes

Directory of Open Access Journals (Sweden)

Autee Arun

2015-01-01

Full Text Available An experimental study of two-phase pressure drop in small diameter tubes orientated horizontally, vertically and at two other downward inclinations of θ= 300 and θ = 600 is described in this paper. Acrylic transparent tubes of internal diameters 4.0, 6.0, and 8.0 mm with lengths of 400 mm were used as the test section. Air-water mixture was used as the working fluid. Two-phase pressure drop was measured and compared with the existing correlations. These correlations are commonly used for calculation of pressure drop in macro and mini-microchannels. It is observed that the existing correlations are inadequate in predicting the two-phase pressure drop in small diameter tubes. Based on the experimental data, a new correlation has been proposed for predicting the two-phase pressure drop. This correlation is developed by modification of Chisholm parameter C by incorporating different parameters. It was found that the proposed correlation predicted two-phase pressure drop at satisfactory level.

Surface conductivity of Mercury provides current closure and may affect magnetospheric symmetry

Directory of Open Access Journals (Sweden)

P. Janhunen

2004-04-01

Full Text Available We study what effect a possible surface conductivity of Mercury has on the closure of magnetospheric currents by making six runs with a quasi-neutral hybrid simulation. The runs are otherwise identical but use different synthetic conductivity models: run 1 has a fully conducting planet, run 2 has a poorly conducting planet ( m and runs 3-6 have one of the hemispheres either in the dawn-dusk or day-night directions, conducting well, the other one being conducting poorly. Although the surface conductivity is not known from observations, educated guesses easily give such conductivity values that magnetospheric currents may close partly within the planet, and as the conductivity depends heavily on the mineral composition of the surface, the possibility of significant horizontal variations cannot be easily excluded. The simulation results show that strong horizontal variations may produce modest magnetospheric asymmetries. Beyond the hybrid simulation, we also briefly discuss the possibility that in the nightside there may be a lack of surface electrons to carry downward current, which may act as a further source of surface-related magnetospheric asymmetry. Key words. Magnetospheric physics (planetary magnetospheres; current systems; solar wind-magnetosphere interactions.6

FLDAS Noah Land Surface Model L4 Monthly Climatology 0.1 x 0.1 degree for Eastern Africa (MERRA-2 and CHIRPS) V001 (FLDAS_NOAH01_C_EA_MC) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The monthly climatology data set contains a series of land surface parameters simulated from the Noah 3.3 model in the Famine Early Warning Systems Network (FEWS...

Monthly results of measurements, September 1986, with supplement related to the three months, July, August, September 1986

International Nuclear Information System (INIS)

1986-10-01

This report of the SCPRI exposes an interpretation of the principal results concerning the routine monitoring of environmental radioactivity in France: atmospheric dusts, rainwater, surface water, underground water, sewage water, drinking water, food chain (milk, vegetables, fishes) seawater around nuclear plant sites and other sites. The activities of various radioisotopes are presented in tables. This report exposes also the results of special radiation measurements resulting from the Chernobyl accident and complementary results related to the three months July, August, September 1986 [fr

Biphilic Surfaces for Enhanced Water Collection from Humid Air

Science.gov (United States)

Benkoski, Jason; Gerasopoulos, Konstantinos; Luedeman, William

Surface wettability plays an important role in water recovery, distillation, dehumidification, and heat transfer. The efficiency of each process depends on the rate of droplet nucleation, droplet growth, and mass transfer. Unfortunately, hydrophilic surfaces are good at nucleation but poor at shedding. Hydrophobic surfaces are the reverse. Many plants and animals overcome this tradeoff through biphilic surfaces with patterned wettability. For example, the Stenocara beetle uses hydrophilic patches on a superhydrophobic background to collect fog from air. Cribellate spiders similarly collect fog on their webs through periodic spindle-knot structures. In this study, we investigate the effects of wettability patterns on the rate of water collection from humid air. The steady state rate of water collection per unit area is measured as a function of undercooling, angle of inclination, water contact angle, hydrophilic patch size, patch spacing, area fraction, and patch height relative to the hydrophobic background. We then model each pattern by comparing the potential and kinetic energy of a droplet as it rolls downwards at a fixed angle. The results indicate that the design rules for collecting fog differ from those for condensation from humid air. The authors gratefully acknowledge the Office of Naval Research for financial support through Grant Number N00014-15-1-2107.

Analysis of MAGSAT and surface data of the Indian region

Science.gov (United States)

Agarwal, G. C. (Principal Investigator)

1983-01-01

Techniques and significant results of an analysis of MAGSAT and surface data of the Indian region are described. Specific investigative tasks included: (1) use of the multilevel data at different altitudes to develop a model for variation of magnetic anomaly with altitude; (2) development of the regional model for the description of main geomagnetic field for the Indian sub-continent using MAGSAT and observatory data; (3) development of regional mathematical model of secular variations over the Indian sub-continent; and (4) downward continuation of the anomaly field obtained from MAGSAT and its combination with the existing observatory data to produce a regional anomaly map for elucidating tectonic features of the Indian sub-continent.

Dynamical Predictability of Monthly Means.

Science.gov (United States)

Shukla, J.

1981-12-01

We have attempted to determine the theoretical upper limit of dynamical predictability of monthly means for prescribed nonfluctuating external forcings. We have extended the concept of `classical' predictability, which primarily refers to the lack of predictability due mainly to the instabilities of synoptic-scale disturbances, to the predictability of time averages, which are determined by the predictability of low-frequency planetary waves. We have carded out 60-day integrations of a global general circulation model with nine different initial conditions but identical boundary conditions of sea surface temperature, snow, sea ice and soil moisture. Three of these initial conditions are the observed atmospheric conditions on 1 January of 1975, 1976 and 1977. The other six initial conditions are obtained by superimposing over the observed initial conditions a random perturbation comparable to the errors of observation. The root-mean-square (rms) error of random perturbations at all the grid points and all the model levels is 3 m s1 in u and v components of wind. The rms vector wind error between the observed initial conditions is >15 m s1.It is hypothesized that for a given averaging period, if the rms error among the time averages predicted from largely different initial conditions becomes comparable to the rms error among the time averages predicted from randomly perturbed initial conditions, the time averages are dynamically unpredictable. We have carried out the analysis of variance to compare the variability, among the three groups, due to largely different initial conditions, and within each group due to random perturbations.It is found that the variances among the first 30-day means, predicted from largely different initial conditions, are significantly different from the variances due to random perturbations in the initial conditions, whereas the variances among 30-day means for days 31-60 are not distinguishable from the variances due to random initial

Solar wind: A possible factor driving the interannual sea surface temperature tripolar mode over North Atlantic

Science.gov (United States)

Xiao, Ziniu; Li, Delin

2016-06-01

The effect of solar wind (SW) on the North Atlantic sea surface temperature (SST) in boreal winter is examined through an analysis of observational data during 1964-2013. The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed (SWS) variations. This pattern is broadly similar to the leading empirical orthogonal function (EOF) mode of interannual variations in the wintertime SSTs over North Atlantic. The time series of this leading EOF mode of SST shows a significant interannual period, which is the same as that of wintertime SWS. This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind, which simultaneously resembles the North Atlantic Oscillation (NAO) in the overlying atmosphere. As compared with the typical low SWS winters, during the typical high SWS winters, the stratospheric polar night jet (PNJ) is evidently enhanced and extends from the stratosphere to the troposphere, even down to the North Atlantic Ocean surface. Notably, the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere. Thus, it seems that the SW is a possible factor for this North Atlantic SST tripolar mode. The dynamical process of stratosphere-troposphere coupling, together with the global atmospheric electric circuit-cloud microphysical process, probably accounts for the particular downward propagation of the SW signal.

Successive 1-Month Weight Increments in Infancy Can Be Used to Screen for Faltering Linear Growth.

Science.gov (United States)

Onyango, Adelheid W; Borghi, Elaine; de Onis, Mercedes; Frongillo, Edward A; Victora, Cesar G; Dewey, Kathryn G; Lartey, Anna; Bhandari, Nita; Baerug, Anne; Garza, Cutberto

2015-12-01

Linear growth faltering in the first 2 y contributes greatly to a high stunting burden, and prevention is hampered by the limited capacity in primary health care for timely screening and intervention. This study aimed to determine an approach to predicting long-term stunting from consecutive 1-mo weight increments in the first year of life. By using the reference sample of the WHO velocity standards, the analysis explored patterns of consecutive monthly weight increments among healthy infants. Four candidate screening thresholds of successive increments that could predict stunting were considered, and one was selected for further testing. The selected threshold was applied in a cohort of Bangladeshi infants to assess its predictive value for stunting at ages 12 and 24 mo. Between birth and age 12 mo, 72.6% of infants in the WHO sample tracked within 1 SD of their weight and length. The selected screening criterion ("event") was 2 consecutive monthly increments below the 15th percentile. Bangladeshi infants were born relatively small and, on average, tracked downward from approximately age 6 to strategy is effective, the estimated preventable proportion in the group who experienced the event would be 34% at 12 mo and 24% at 24 mo. This analysis offers an approach for frontline workers to identify children at risk of stunting, allowing for timely initiation of preventive measures. It opens avenues for further investigation into evidence-informed application of the WHO growth velocity standards. © 2015 American Society for Nutrition.

Variability of cold season surface air temperature over northeastern China and its linkage with large-scale atmospheric circulations

Science.gov (United States)

Zhuang, Yuanhuang; Zhang, Jingyong; Wang, Lin

2018-05-01

Cold temperature anomalies and extremes have profound effects on the society, the economy, and the environment of northeastern China (NEC). In this study, we define the cold season as the months from October to April, and investigate the variability of cold season surface air temperature (CSAT) over NEC and its relationships with large-scale atmospheric circulation patterns for the period 1981-2014. The empirical orthogonal function (EOF) analysis shows that the first EOF mode of the CSAT over NEC is characterized by a homogeneous structure that describes 92.2% of the total variance. The regionally averaged CSAT over NEC is closely linked with the Arctic Oscillation ( r = 0.62, 99% confidence level) and also has a statistically significant relation with the Polar/Eurasian pattern in the cold season. The positive phases of the Arctic Oscillation and the Polar/Eurasian pattern tend to result in a positive geopotential height anomaly over NEC and a weakened East Asian winter monsoon, which subsequently increase the CSAT over NEC by enhancing the downward solar radiation, strengthening the subsidence warming and warm air advection. Conversely, the negative phases of these two climate indices result in opposite regional atmospheric circulation anomalies and decrease the CSAT over NEC.

A hybrid model to predict the onset of gas entrainment with surface tension effects

International Nuclear Information System (INIS)

Saleh, W.; Bowden, R.C.; Hassan, I.G.; Kadem, L.

2008-01-01

The onset of gas entrainment, in a single downward oriented discharge from a stratified gas-liquid region with was modeled. The assumptions made in the development of the model reduced the problem to that of a potential flow. The discharge was modeled as a point-sink. Through use of the Kelvin-Laplace equation the model included the effects of surface tension. The resulting model required further knowledge of the flow field, specifically the dip radius of curvature prior to the onset of gas entrainment. The dip shape and size was investigated experimentally and correlations were provided to characterize the dip in terms of the discharge Froude number. The experimental correlation was used in conjunction with the theoretical model to predict the critical height. The results showed that by including surface tension effects the predicted critical height showed excellent agreement with experimental data. Surface tension reduces the critical height through the Bond number

An analysis of prediction skill of monthly mean climate variability

Energy Technology Data Exchange (ETDEWEB)

Kumar, Arun; Chen, Mingyue; Wang, Wanqiu [Climate Prediction Center, National Centers for Environmental Prediction (CPC/NCEP), Camp Springs, MD (United States)

2011-09-15

In this paper, lead-time and spatial dependence in skill for prediction of monthly mean climate variability is analyzed. The analysis is based on a set of extensive hindcasts from the Climate Forecast System at the National Centers for Environmental Prediction. The skill characteristics of initialized predictions is also compared with the AMIP simulations forced with the observed sea surface temperature (SST) to quantify the role of initial versus boundary conditions in the prediction of monthly means. The analysis is for prediction of monthly mean SST, precipitation, and 200-hPa height. The results show a rapid decay in skill with lead time for the atmospheric variables in the extratropical latitudes. Further, after a lead-time of approximately 30-40 days, the skill of monthly mean prediction is essentially a boundary forced problem, with SST anomalies in the tropical central/eastern Pacific playing a dominant role. Because of the larger contribution from the atmospheric internal variability to monthly time-averages (compared to seasonal averages), skill for monthly mean prediction associated with boundary forcing is also lower. The analysis indicates that the prospects of skillful prediction of monthly means may remain a challenging problem, and may be limited by inherent limits in predictability. (orig.)

CAUSES: On the Role of Surface Energy Budget Errors to the Warm Surface Air Temperature Error Over the Central United States

Science.gov (United States)

Ma, H.-Y.; Klein, S. A.; Xie, S.; Zhang, C.; Tang, S.; Tang, Q.; Morcrette, C. J.; Van Weverberg, K.; Petch, J.; Ahlgrimm, M.; Berg, L. K.; Cheruy, F.; Cole, J.; Forbes, R.; Gustafson, W. I.; Huang, M.; Liu, Y.; Merryfield, W.; Qian, Y.; Roehrig, R.; Wang, Y.-C.

2018-03-01

Many weather forecast and climate models simulate warm surface air temperature (T2m) biases over midlatitude continents during the summertime, especially over the Great Plains. We present here one of a series of papers from a multimodel intercomparison project (CAUSES: Cloud Above the United States and Errors at the Surface), which aims to evaluate the role of cloud, radiation, and precipitation biases in contributing to the T2m bias using a short-term hindcast approach during the spring and summer of 2011. Observations are mainly from the Atmospheric Radiation Measurement Southern Great Plains sites. The present study examines the contributions of surface energy budget errors. All participating models simulate too much net shortwave and longwave fluxes at the surface but with no consistent mean bias sign in turbulent fluxes over the Central United States and Southern Great Plains. Nevertheless, biases in the net shortwave and downward longwave fluxes as well as surface evaporative fraction (EF) are contributors to T2m bias. Radiation biases are largely affected by cloud simulations, while EF bias is largely affected by soil moisture modulated by seasonal accumulated precipitation and evaporation. An approximate equation based upon the surface energy budget is derived to further quantify the magnitudes of radiation and EF contributions to T2m bias. Our analysis ascribes that a large EF underestimate is the dominant source of error in all models with a large positive temperature bias, whereas an EF overestimate compensates for an excess of absorbed shortwave radiation in nearly all the models with the smallest temperature bias.

On the warm nearshore bias in Pathfinder monthly SST products over Eastern Boundary upwelling systems

CSIR Research Space (South Africa)

Dufois, F

2012-01-01

Full Text Available Using in situ sea surface temperature (SST) data and MODIS/TERRA SST, the monthly AVHRR Pathfinder (version 5.0 and 5.2) SST product was evaluated within the four main Eastern Boundary Upwelling Systems. A warm bias in the monthly Pathfinder data...

Early stages of Cs adsorption mechanism for GaAs nanowire surface

Science.gov (United States)

Diao, Yu; Liu, Lei; Xia, Sihao; Feng, Shu

2018-03-01

In this study, the adsorption mechanism of Cs adatoms on the (100) surface of GaAs nanowire with [0001] growth direction is investigated utilizing first principles method based on density function theory. The adsorption energy, work function, atomic structure and electronic property of clean surface and Cs-covered surfaces with different coverage are discussed. Results show that when only one Cs is adsorbed on the surface, the most favorable adsorption site is BGa-As. With increasing Cs coverage, work function gradually decreases and gets its minimum at 0.75 ML, then rises slightly when Cs coverage comes to 1 ML, indicating the existence of 'Cs-kill' phenomenon. According to further analysis, Cs activation process can effectively reduce the work function due to the formation of a downward band bending region and surface dipole moment directing from Cs adatom to the surface. As Cs coverage increases, the conduction band minimum and valence band maximum both shift towards lower energy side, contributed by the orbital hybridization between Cs-5s, Cs-5p states and Ga-4p, As-4s, As-4p states near Fermi level. The theoretical calculations and analysis in this study can improve the Cs activation technology for negative electron affinity optoelectronic devices based on GaAs nanowires, and also provide a reference for the further Cs/O or Cs/NF3 activation process.

Month-hour distributions of zenith luminance and diffuse illuminance in Madrid

International Nuclear Information System (INIS)

Soler, Alfonso; Gopinathan, Kannam K.; Robledo, Luis; Ruiz, Enrique

2004-01-01

Month-hour equal mean zenith luminance contours are obtained from one year of data of zenith luminance measurements for cloudless, overcast and partly cloudy skies and also when the combined data for all sky types are considered. For many hours in different months, the overcast sky luminance values are roughly about three times the cloudless sky luminance values and one and a half times the partly cloudy sky values. The dependence of month-hour equal mean zenith luminance contours on the ratio of global to extraterrestrial illuminance on a horizontal surface is also given. From equal mean zenith luminance contours, the approximate values of the mean zenith luminance for different sky conditions and different hours and months of the year can be easily obtained. Month-hour equal mean diffuse illuminance contours are obtained from diffuse illuminance measurements performed during the period 1992-1998. The dependence on solar altitude of the monthly average hourly values of diffuse illuminance is given and compared to the corresponding one obtained from data for Bet Dagan (Israel)

T Tank Farm Interim Surface Barrier Demonstration -- Vadose Zone Monitoring FY07 Report

International Nuclear Information System (INIS)

Zhang, Z. F.; Strickland, Christopher E.; Keller, Jason M.; Wittreich, Curtis D.; Sydnor, Harold A.

2008-01-01

deeper were relatively stable during the whole monitoring period. The soil-water content variation was between 0.012 and 0.043 m3m-3, with smaller variation in deeper soil. The neutron probe measurements show that, the normalized neutron counts had relatively large variation in the soil above 5 ft (1.52 m) bgs and were relatively stable in the deeper soil. The peak values of the soil-water-pressure head at 1-m depth appeared in early January 2007 followed by a decrease. The heat-dissipation unit at the 2.0-m depth showed increasing soil-water pressures from January to April or May 2007 before they started decreasing. The soil-water-pressure heads at 5- and 10-m depths were relatively stable. During FY07, the soil-water-pressure-head variation was between 0.48 and 3.49 m H2O-height, with smaller variation in deeper soil. The soil water was moving downward from late December 2006 to mid-April 2007 and upward at other time in the soil from 1 to 2 m bgs of Nest A. The soil-water movement was always downward below 2 m bgs for Nest A and below 1 m bgs for Nest B. This dominant downward moisture movement indicates that, under the condition without a surface barrier, the soil was gaining water from precipitation in FY07.

Simulation and transient analyses of a complete passive heat removal system in a downward cooling pool-type material testing reactor against a complete station blackout and long-term natural convection mode using the RELAP5/3.2 code

Energy Technology Data Exchange (ETDEWEB)

Hedayat, Afshin [Reactor and Nuclear Safety School, Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

2017-08-15

In this paper, a complete station blackout (SBO) or complete loss of electrical power supplies is simulated and analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR). The scenario is traced in the absence of active cooling systems and operators. The code nodalization is successfully benchmarked against experimental data of the reactor's operating parameters. The passive heat removal system includes downward water cooling after pump breakdown by the force of gravity (where the coolant streams down to the unfilled portion of the holdup tank), safety flapper opening, flow reversal from a downward to an upward cooling direction, and then the upward free convection heat removal throughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-term natural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analyses focus on the safety flapper valve operation and flow reversal mode. Long-term analyses include simulation of both complete SBO and long-term operation of the free convection mode. Results are promising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTR thermal–hydraulic simulations without any oscillation; moreover, the Tehran Research Reactor is conservatively safe against the complete SBO and long-term free convection operation.

Simulation and transient analyses of a complete passive heat removal system in a downward cooling pool-type material testing reactor against a complete station blackout and long-term natural convection mode using the RELAP5/3.2 code

Directory of Open Access Journals (Sweden)

Afshin Hedayat

2017-08-01

Full Text Available In this paper, a complete station blackout (SBO or complete loss of electrical power supplies is simulated and analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR. The scenario is traced in the absence of active cooling systems and operators. The code nodalization is successfully benchmarked against experimental data of the reactor's operating parameters. The passive heat removal system includes downward water cooling after pump breakdown by the force of gravity (where the coolant streams down to the unfilled portion of the holdup tank, safety flapper opening, flow reversal from a downward to an upward cooling direction, and then the upward free convection heat removal throughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-term natural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analyses focus on the safety flapper valve operation and flow reversal mode. Long-term analyses include simulation of both complete SBO and long-term operation of the free convection mode. Results are promising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTR thermal–hydraulic simulations without any oscillation; moreover, the Tehran Research Reactor is conservatively safe against the complete SBO and long-term free convection operation.

Spin-polarized scanning tunneling spectroscopy of self-organized nanoscale Co islands on Au(111) surfaces.

Science.gov (United States)

Schouteden, K; Muzychenko, D A; Van Haesendonck, C

2008-07-01

Magnetic monolayer and bilayer Co islands of only a few nanometer in size were grown by atomic deposition on atomically flat Au(111) films. The islands were studied in situ by scanning tunneling microscopy (STM) and spectroscopy at low temperatures. Spin-resolved tunneling spectroscopy, using an STM tip with a magnetic coating, revealed that the Co islands exhibit a net magnetization perpendicular to the substrate surface due to the presence of spin-polarized d-states. A random distribution of islands with either upward or downward pointing magnetization was observed, without any specific correlation of magnetization orientation with island size or island height.

The impact of monthly variation of the Pacific–North America (PNA teleconnection pattern on wintertime surface-layer aerosol concentrations in the United States

Directory of Open Access Journals (Sweden)

J. Feng

2016-04-01

Full Text Available The Pacific–North America teleconnection (PNA is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variations of the PNA phase (positive or negative phase on wintertime surface-layer aerosol concentrations in the United States (US by analyzing observations during 1999–2013 from the Air Quality System of the Environmental Protection Agency (EPA-AQS and the model results for 1986–2006 from the global three-dimensional Goddard Earth Observing System (GEOS chemical transport model (GEOS-Chem. The composite analyses on the EPA-AQS observations over 1999–2013 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon aerosols over the US were higher in the PNA positive phases (25 % of the winter months examined, and this fraction of months had the highest positive PNA index values than in the PNA negative phases (25 % of the winter months examined, and this fraction of months had the highest negative PNA index values by 1.0 µg m−3 (8.7 %, 0.01 µg m−3 (0.5 %, 0.3 µg m−3 (29.1 %, 0.1 µg m−3 (11.9 %, 0.6 µg m−3 (13.5 %, and 0.2 µg m−3 (27.8 %, respectively. The simulated geographical patterns of the differences in concentrations of all aerosol species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation, the pattern correlation coefficients were calculated to show the impacts of PNA-induced variations in meteorological fields on aerosol concentrations. The PNA phase was found (i to influence sulfate concentrations mainly through changes in planetary boundary layer height (PBLH, precipitation (PR, and temperature; (ii to influence nitrate concentrations mainly through changes in temperature; and (iii to influence concentrations of ammonium, organic carbon, and black

Extended Reconstructed Sea Surface Temperature (ERSST)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature analysis derived from the International Comprehensive...

A binary genetic programing model for teleconnection identification between global sea surface temperature and local maximum monthly rainfall events

Science.gov (United States)

Danandeh Mehr, Ali; Nourani, Vahid; Hrnjica, Bahrudin; Molajou, Amir

2017-12-01

The effectiveness of genetic programming (GP) for solving regression problems in hydrology has been recognized in recent studies. However, its capability to solve classification problems has not been sufficiently explored so far. This study develops and applies a novel classification-forecasting model, namely Binary GP (BGP), for teleconnection studies between sea surface temperature (SST) variations and maximum monthly rainfall (MMR) events. The BGP integrates certain types of data pre-processing and post-processing methods with conventional GP engine to enhance its ability to solve both regression and classification problems simultaneously. The model was trained and tested using SST series of Black Sea, Mediterranean Sea, and Red Sea as potential predictors as well as classified MMR events at two locations in Iran as predictand. Skill of the model was measured in regard to different rainfall thresholds and SST lags and compared to that of the hybrid decision tree-association rule (DTAR) model available in the literature. The results indicated that the proposed model can identify potential teleconnection signals of surrounding seas beneficial to long-term forecasting of the occurrence of the classified MMR events.

A new integrated and homogenized global monthly land surface air temperature dataset for the period since 1900

Science.gov (United States)

Xu, Wenhui; Li, Qingxiang; Jones, Phil; Wang, Xiaolan L.; Trewin, Blair; Yang, Su; Zhu, Chen; Zhai, Panmao; Wang, Jinfeng; Vincent, Lucie; Dai, Aiguo; Gao, Yun; Ding, Yihui

2018-04-01

A new dataset of integrated and homogenized monthly surface air temperature over global land for the period since 1900 [China Meteorological Administration global Land Surface Air Temperature (CMA-LSAT)] is developed. In total, 14 sources have been collected and integrated into the newly developed dataset, including three global (CRUTEM4, GHCN, and BEST), three regional and eight national sources. Duplicate stations are identified, and those with the higher priority are chosen or spliced. Then, a consistency test and a climate outlier test are conducted to ensure that each station series is quality controlled. Next, two steps are adopted to assure the homogeneity of the station series: (1) homogenized station series in existing national datasets (by National Meteorological Services) are directly integrated into the dataset without any changes (50% of all stations), and (2) the inhomogeneities are detected and adjusted for in the remaining data series using a penalized maximal t test (50% of all stations). Based on the dataset, we re-assess the temperature changes in global and regional areas compared with GHCN-V3 and CRUTEM4, as well as the temperature changes during the three periods of 1900-2014, 1979-2014 and 1998-2014. The best estimates of warming trends and there 95% confidence ranges for 1900-2014 are approximately 0.102 ± 0.006 °C/decade for the whole year, and 0.104 ± 0.009, 0.112 ± 0.007, 0.090 ± 0.006, and 0.092 ± 0.007 °C/decade for the DJF (December, January, February), MAM, JJA, and SON seasons, respectively. MAM saw the most significant warming trend in both 1900-2014 and 1979-2014. For an even shorter and more recent period (1998-2014), MAM, JJA and SON show similar warming trends, while DJF shows opposite trends. The results show that the ability of CMA-LAST for describing the global temperature changes is similar with other existing products, while there are some differences when describing regional temperature changes.

Comparison of surface sensible and latent heat fluxes over the Tibetan Plateau from reanalysis and observations

Science.gov (United States)

Xie, Jin; Yu, Ye; Li, Jiang-lin; Ge, Jun; Liu, Chuan

2018-02-01

Surface sensible and latent heat fluxes (SH and LE) over the Tibetan Plateau (TP) have been under research since 1950s, especially for recent several years, by mainly using observation, reanalysis, and satellite data. However, the spatiotemporal changes are not consistent among different studies. This paper focuses on the spatiotemporal variation of SH and LE over the TP from 1981 to 2013 using reanalysis data sets (ERA-Interim, JRA-55, and MERRA) and observations. Results show that the spatiotemporal changes from the three reanalysis data sets are significantly different and the probable causes are discussed. Averaged for the whole TP, both SH and LE from MERRA are obviously higher than the other two reanalysis data sets. ERA-Interim shows a significant downward trend for SH and JRA-55 shows a significant increase of LE during the 33 years with other data sets having no obvious changes. By comparing the heat fluxes and some climate factors from the reanalysis with observations, it is found that the differences of heat fluxes among the three reanalysis data sets are closely related to their differences in meteorological conditions as well as the different parameterizations for surface transfer coefficients. In general, the heat fluxes from the three reanalysis have a better representation in the western TP than that in the eastern TP under inter-annual scale. While in terms of monthly variation, ERA-Interim may have better applicability in the eastern TP with dense vegetation conditions, while SH of JRA-55 and LE of MERRA are probably more representative for the middle and western TP with poor vegetation conditions.

SAFARI 2000 Monthly Climatology for the 20th Century (New et al.)

Data.gov (United States)

National Aeronautics and Space Administration — This is a data set of mean monthly surface climate data over Southern Africa for nearly all of the twentieth century. The data set is gridded at 0.5-degree...

Natural convection in a water tank with a heated horizontal plate facing downward

International Nuclear Information System (INIS)

Yang, Sun Kyoo; Jung, Moon Kee; Helmut Hoffmann

1995-01-01

Experimental and computational studies were carried out to investigate the natural convection of the single phase flow in a tank with a heated horizontal plate facing downward. This is a simplified model for investigations of the influence of a core melt at the bottom of a reactor vessel on the thermal hydraulic behavior in a water filled cavity surrounding the vessel. In this case the vessel is simulated by a hexahedron insulated box with a heated plate horizontally mounted at the bottom of the box. The box with the heated plate is installed in a water filled hexahedron tank. Coolers are immersed in the U-type water volume between the box and the tank. Although the multicomponent flows exist more probably below the heated plate in reality, present study concentrates on the single phase flow in a first step prior to investigating the complicated multicomponent thermal hydraulic phenomena. In the present study, in order to get a better understanding for the natural convection characteristics below the heated plate, the velocity and temperature are measured by LDA(Laser Doppler Anemometry) and thermocouples, respectively. And flow fields are visualized by taking pictures of the flow region with suspended particles. The results show the occurrence of a very effective circulation of the fluid in the whole flow area as the heater and coolers are put into operation. In the remote region below the heated plate the flow is nearly stagnant, and a remarkable temperature stratification can be observed with very thin thermal boundary. Analytical predictions using the FLUTAN code show a reasonable matching of the measured velocity fields. 18 figs., 2 tabs., 18 refs. (Author)

Surface Weather Observations

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Surface Weather Observation Collection consists primarily of hourly, synoptic, daily, and monthly forms submitted to the archive by the National Weather Service...

Galileo Probe Doppler Residuals as the Wave-Dynamical Signature of Weakly Stable, Downward-Increasing Stratification in Jupiter's Deep Wind Layer

Science.gov (United States)

Allison, Michael; Atkinson, David H.; Hansen, James E. (Technical Monitor)

2001-01-01

Doppler radio tracking of the Galileo probe-to-orbiter relay, previously analyzed for its in situ measure of Jupiter's zonal wind at the equatorial entry site, also shows a record of significant residual fluctuations apparently indicative of varying vertical motions. Regular oscillations over pressure depth in the residual Doppler measurements of roughly 1-8 Hz (increasing upward), as filtered over a 134 sec window, are most plausibly interpreted as gravity waves, and imply a weak, but downward increasing static stability within the 5 - 20 bar region of Jupiter's atmosphere. A matched extension to deeper levels of an independent inertial stability constraint from the measured vertical wind shear at 1 - 4 bars is roughly consistent with a static stability of approximately 0.5 K/km near the 20 bar level, as independently detected by the probe Atmospheric Structure Instrument.

SAFARI 2000 Monthly Climatology for the 20th Century (New et al.)

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This is a data set of mean monthly surface climate data over Southern Africa for nearly all of the twentieth century. The data set is gridded at 0.5-degree...

Comparison of Monthly Mean Cloud Fraction and Cloud Optical depth Determined from Surface Cloud Radar, TOVS, AVHRR, and MODIS over Barrow, Alaska

Science.gov (United States)

Uttal, Taneil; Frisch, Shelby; Wang, Xuan-Ji; Key, Jeff; Schweiger, Axel; Sun-Mack, Sunny; Minnis, Patrick

2005-01-01

A one year comparison is made of mean monthly values of cloud fraction and cloud optical depth over Barrow, Alaska (71 deg 19.378 min North, 156 deg 36.934 min West) between 35 GHz radar-based retrievals, the TOVS Pathfinder Path-P product, the AVHRR APP-X product, and a MODIS based cloud retrieval product from the CERES-Team. The data sets represent largely disparate spatial and temporal scales, however, in this paper, the focus is to provide a preliminary analysis of how the mean monthly values derived from these different data sets compare, and determine how they can best be used separately, and in combination to provide reliable estimates of long-term trends of changing cloud properties. The radar and satellite data sets described here incorporate Arctic specific modifications that account for cloud detection challenges specific to the Arctic environment. The year 2000 was chosen for this initial comparison because the cloud radar data was particularly continuous and reliable that year, and all of the satellite retrievals of interest were also available for the year 2000. Cloud fraction was chosen as a comparison variable as accurate detection of cloud is the primary product that is necessary for any other cloud property retrievals. Cloud optical depth was additionally selected as it is likely the single cloud property that is most closely correlated to cloud influences on surface radiation budgets.

Orientation-dependent chemistry and band-bending of Ti on polar ZnO surfaces.

Science.gov (United States)

Borghetti, Patrizia; Mouchaal, Younes; Dai, Zongbei; Cabailh, Gregory; Chenot, Stéphane; Lazzari, Rémi; Jupille, Jacques

2017-04-19

Orientation-dependent reactivity and band-bending are evidenced upon Ti deposition (1-10 Å) on polar ZnO(0001)-Zn and ZnO(0001[combining macron])-O surfaces. At the onset of the Ti deposition, a downward band-bending was observed on ZnO(0001[combining macron])-O while no change occurred on ZnO(0001)-Zn. Combining this with the photoemission analysis of the Ti 2p core level and Zn L 3 (L 2 )M 45 M 45 Auger transition, it is established that the Ti/ZnO reaction is of the form Ti + 2ZnO → TiO 2 + 2Zn on ZnO(0001)-Zn and Ti + yZnO → TiZn x O y + (y - x)Zn on ZnO(0001[combining macron])-O. Consistently, upon annealing thicker Ti adlayers, the metallic zinc is removed to leave ZnO(0001)-Zn surfaces covered with a TiO 2 -like phase and ZnO(0001[combining macron])-O surfaces covered with a defined (Ti, Zn, O) compound. Finally, a difference in the activation temperature between the O-terminated (500 K) and Zn-terminated (700 K) surfaces is observed, which is tentatively explained by different electric fields in the space charge layer at ZnO surfaces.

A review of diazinon use, contamination in surface waters, and regulatory actions in California across water years 1992-2014.

Science.gov (United States)

Wang, Dan; Singhasemanon, Nan; Goh, Kean S

2017-07-01

Diazinon is an organophosphorus insecticide that has been widely used in the USA and in California resulting in contamination of surface waters. Several federal and state regulations have been implemented with the aim of reducing its impact to human health and the environment, e.g., the cancellation of residential use products by the USEPA and dormant spray regulations by the California Department of Pesticide Regulation. This study reviewed the change in diazinon use and surface water contamination in accordance with the regulatory actions implemented in California over water years 1992-2014. We observed that use amounts began declining when agencies announced the intention to regulate certain use patterns and continued to decline after the implementation of those programs and regulations. The reduction in use amounts led to a downward trend in concentration data and exceedance frequencies in surface waters. Moreover, we concluded that diazinon concentrations in California's surface waters in recent years (i.e., water years 2012-2014) posed a de minimis risk to aquatic organisms.

Spatial distribution of potential near surface moisture flux at Yucca Mountain

International Nuclear Information System (INIS)

Flint, A.L.; Flint, L.E.

1994-01-01

An estimate of the areal distribution of present-day surface liquid moisture flux at Yucca Mountain was made using field measured water contents and laboratory measured rock properties. Using available data for physical and hydrologic properties (porosity, saturated hydraulic conductivity, moisture retention functions) of the volcanic rocks, surface lithologic units that are hydrologically similar were delineated. Moisture retention and relative permeability functions were assigned to each surface unit based on the similarity of the mean porosity and saturated hydraulic conductivity of the surface unit to laboratory samples of the same lithology. The potential flux into the mountain was estimated for each surface hydrologic unit using the mean saturated hydraulic conductivity for each unit and assuming all matrix flow. Using measured moisture profiles for each of the surface units, estimates were made of the depth at which seasonal fluctuations diminish and steady state downward flux conditions are likely to exist. The hydrologic properties at that depth were used with the current relative saturation of the tuff, to estimate flux as the unsaturated hydraulic conductivity. This method assumes a unit gradient. The range in estimated flux was 0.02 mm/yr for the welded Tiva Canyon to 13.4 mm/yr for the nonwelded Paintbrush Tuff. The areally averaged flux was 1.4 mm/yr. The major zones of high flux occur to the north of the potential repository boundary where the nonwelded tuffs are exposed in the major drainages

Spatial distribution of potential near surface moisture flux at Yucca Mountain

International Nuclear Information System (INIS)

Flint, A.L.; Flint, L.E.

1994-01-01

An estimate of the areal distribution of present-day surface liquid moisture flux at Yucca Mountain was made using field measured water contents and laboratory measured rock properties. Using available data for physical and hydrologic properties (porosity, saturated hydraulic conductivity moisture retention functions) of the volcanic rocks, surface lithologic units that are hydrologically similar were delineated. Moisture retention and relative permeability functions were assigned to each surface unit based on the similarity of the mean porosity and saturated hydraulic conductivity of the surface unit to laboratory samples of the same lithology. The potential flux into the mountain was estimated for each surface hydrologic unit using the mean saturated hydraulic conductivity for each unit and assuming all matrix flow. Using measured moisture profiles for each of the surface units, estimates were made of the depth at which seasonal fluctuations diminish and steady state downward flux conditions are likely to exist. The hydrologic properties at that depth were used with the current relative saturation of the tuff, to estimate flux as the unsaturated hydraulic conductivity. This method assumes a unit gradient. The range in estimated flux was 0.02 mm/yr for the welded Tiva Canyon to 13.4 mm/yr for the nonwelded Paintbrush Tuff. The areally averaged flux was 1.4 mm/yr. The major zones of high flux occur to the north of the potential repository boundary where the nonwelded tuffs are exposed in the major drainages

Possible influence of long-term sea surface temperature anomalies in the tropical Pacific on global zone

Energy Technology Data Exchange (ETDEWEB)

Komhyr, W D; Oltmans, S J; Grass, R D [Atmospheric Administration Climate Monitoring and Diagnostics Lab., Boulder, CO (USA); Leonard, R K [Colorado Univ., Boulder, CO (USA)

1991-01-01

A significant negative correlation exists between summer sea surface temperatures (SSTs) in the east equatorial Pacific and late-October south pole total ozone values. SSTs in the eastern equatorial Pacific were anomalously warmer during 1976-1987 compared with 1962-1975. QBO (quasi-biennial oscillation) easterly winds in the equatorial Pacific stratosphere were generally stronger after 1975. Before the early-to-mid 1970s the trend in global ozone was generally upward, but then turned downward. Total ozone at Hawaii and Samoa, which had been decreasing during 1976-1987, showed recovery to mid-1970s values in 1988-1989 following a drop in SSTs in the eastern equatorial Pacific to low values last observed there prior to 1976. During late October 1988, total south pole ozone, which had decreased from ca 280 Dobson units (DU) before 1980 to 140 DU in 1987, suddenly recovered to 250 DU, though substantial ozone depletion by heterogeneous photochemical processes involving polar stratospheric clouds was still evident in the south pole ozone vertical profiles. These observations suggest that the downward trend in ozone observed over the globe in recent years may have been at least partly meteorologically induced, possibly via modulation by the warmer tropical Pacific ocean waters of QBO easterly winds at the equator, of Hadley Cell circulation, or other factors. A cursory analysis of geostrophic wind flow around the Baffin Island low suggests a meteorological influence on the observed downward trend in ozone over North America during the past decade. Because ozone has a lifetime that varies from years to minutes, changes in atmospheric dynamics have a potential to not only redistribute ozone over the globe but also to change global ozone abundance. 47 refs., 5 figs., 1 tab.

Artificial Intelligence Mechanisms on Interactive Modified Simplex Method with Desirability Function for Optimising Surface Lapping Process

Directory of Open Access Journals (Sweden)

Pongchanun Luangpaiboon

2014-01-01

Full Text Available A study has been made to optimise the influential parameters of surface lapping process. Lapping time, lapping speed, downward pressure, and charging pressure were chosen from the preliminary studies as parameters to determine process performances in terms of material removal, lap width, and clamp force. The desirability functions of the-nominal-the-best were used to compromise multiple responses into the overall desirability function level or D response. The conventional modified simplex or Nelder-Mead simplex method and the interactive desirability function are performed to optimise online the parameter levels in order to maximise the D response. In order to determine the lapping process parameters effectively, this research then applies two powerful artificial intelligence optimisation mechanisms from harmony search and firefly algorithms. The recommended condition of (lapping time, lapping speed, downward pressure, and charging pressure at (33, 35, 6.0, and 5.0 has been verified by performing confirmation experiments. It showed that the D response level increased to 0.96. When compared with the current operating condition, there is a decrease of the material removal and lap width with the improved process performance indices of 2.01 and 1.14, respectively. Similarly, there is an increase of the clamp force with the improved process performance index of 1.58.

Variations in the incidence and burden of illnesses and injuries among non-retiree service members in the earliest, middle, and last 6 months of their careers, active component, U.S. Armed Forces, 2000-2015.

Science.gov (United States)

Uptegraft, Colby C; Stahlman, Shauna

2018-06-01

This report uses routinely collected data in the Defense Medical Surveillance System (DMSS) to characterize the incidence and burden of medical conditions throughout the careers of service members separating from the active component of the U.S. Armed Forces between 1 October 2014 and 30 September 2015. Three surveillance periods between 30 September 2000 and 30 September 2015 were defined by each individual's time in service: early (first 6 months), middle (middle 6 months), and late (last 6 months). Overall, separating service members were most often aged 25-34 years (59.4%), male (84.0%), non-Hispanic white (64.0%), junior enlisted (52.4%), in the Marine Corps (33.1%), serving in a repair/engineering occupation (33.0%), and had never deployed (52.5%). The top five burden of disease categories across surveillance periods by sex were remarkably similar, including mental health disorders, which exhibited similar upward trends across the three surveillance periods (males: 1.3%, 17.0%, and 35.6%; females: 1.8%, 15.1%, and 32.4%, respectively). The most common diagnoses exhibiting upward, downward, or bimodal trends by incidence rate differences were mental health disorders, respiratory infections/diseases, and musculoskeletal diseases, respectively.

Month-to-month variability of Indian summer monsoon rainfall in 2016: role of the Indo-Pacific climatic conditions

Science.gov (United States)

Chowdary, Jasti S.; Srinivas, G.; Du, Yan; Gopinath, K.; Gnanaseelan, C.; Parekh, Anant; Singh, Prem

2018-03-01

Indian summer monsoon (ISM) rainfall during 2016 exhibited a prominent month-to-month fluctuations over India, with below normal rainfall in June and August and above normal rainfall in July. The factors determining the month-to-month fluctuations in ISM rainfall during 2016 are investigated with main focus on the Indo-Pacific climatic anomalies. Warm sea surface temperature (SST) anomalies associated with super El Niño 2015 disappeared by early summer 2016 over the central and eastern Pacific. On the other hand, negative Indian Ocean dipole (IOD) like SST anomaly pattern over the equatorial Indian Ocean and anomalous anticyclonic circulation over the western North Pacific (WNP) are reported in summer 2016 concurrently with decaying El Niño/developing La Niña phase. Observations revealed that the low rainfall over central north India in June is due to moisture divergence caused by the westward extension of ridge corresponding to WNP anticyclone and subsidence induced by local Hadley cell partly related to negative IOD. Low level convergence of southeasterly wind from Bay of Bengal associated with weak WNP anticyclone and northwesterly wind corresponding to anticyclonic circulation over the northwest India remarkably contributed to positive rainfall in July over most of the Indian subcontinent. While reduced rainfall over the Indian subcontinent in August 2016 is associated with the anomalous moisture transport from ISM region to WNP region, in contrast to July, due to local cyclogenesis corroborated by number of tropical cyclones in the WNP. In addition to this, subsidence related to strong convection supported by cyclonic circulation over the WNP also resulted in low rainfall over the ISM region. Coupled General Circulation model sensitivity experiments confirmed that strong convective activities associated with cyclonic circulation over the WNP is primarily responsible for the observed negative ISM rainfall anomalies in August 2016. It is noted that the Indo

4 km NODC/RSMAS AVHRR Pathfinder Cloud Screened Version 5.0 Monthly Climatologies (1985-2006) (NODC Accession 0110657)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains a global, 4km monthly sea surface temperature climatology derived from harmonic analysis of the AVHRR Pathfinder Version 5.0 sea surface...

Progress in Understanding Land-Surface-Atmosphere Coupling from LBA Research

Directory of Open Access Journals (Sweden)

Alan K Betts

2010-06-01

Full Text Available LBA research has deepened our understanding of the role of soil water storage, clouds and aerosols in land-atmosphere coupling. We show how the reformulation of cloud forcing in terms of an effective cloud albedo per unit area of surface gives a useful measure of the role of clouds in the surface energy budget over the Amazon. We show that the diurnal temperature range has a quasi-linear relation to the daily mean longwave cooling; and to effective cloud albedo because of the tight coupling between the near-surface climate, the boundary layer and the cloud field. The coupling of surface and atmospheric processes is critical to the seasonal cycle: deep forest rooting systems make water available throughout the year, whereas in the dry season the shortwave cloud forcing is reduced by regional scale subsidence, so that more light is available for photosynthesis. At sites with an annual precipitation above 1900 mm and a dry season length less than 4 months, evaporation rates increased in the dry season, coincident with increased radiation. In contrast, ecosystems with precipitation less than 1700 mm and a longer dry season showed clear evidence of reduced evaporation in the dry season coming from water stress. In all these sites, the seasonal variation of the effective cloud albedo is a major factor in determining the surface available energy. Dry season fires add substantial aerosol to the atmosphere. Aerosol scattering and absorption both reduce the total downward surface radiative flux, but increase the diffuse/direct flux ratio, which increases photosynthetic efficiency. Convective plumes produced by fires enhance the vertical transport of aerosols over the Amazon, and effectively inject smoke aerosol and gases directly into the middle troposphere with substantial impacts on mid- tropospheric dispersion. In the rainy season in Rondônia, convection in low-level westerly flows with low aerosol content resembles oceanic convection with

Long term subsidence movements and behavior of subsidence-damaged structures

International Nuclear Information System (INIS)

Mahar, J.W.; Marino, G.G.

1999-01-01

Surface ground movement related to sag mine subsidence has been monitored above Illinois abandoned room and pillar coal workings for periods of more than 15 years. The long term movement related to a specific mine subsidence is typically small relative to the initial displacements but have caused crack and tilt damage in both repaired and unrepaired structures. Seasonal variations in ground surface elevations are superimposed on the downward movement related to mine subsidence. Thus it is necessary to measure long term subsidence movement at about the same time each year in order to minimize environmental factors. This paper presents long term monitoring data from five subsidence sags in central and southern Illinois. The abandoned coal mine workings are located at depths of 160 to 460 ft below the ground surface. measured residual mine subsidence ranges between 1.4 and 3.6 in. 4.4 to 15 years after mine failure. The magnitude of downward displacement is greater than settlement design values (1 in.) and are at rates (0.0004 to 0.0056 ft/month) that cause damage to structures. Most of the damage in unrepaired structures occurs along existing cracks and separations. In all five cases, the ground movements are continuing at residual rates. Sag subsidence movement in Illinois takes place for a minimum of five years after the damage is manifested at the ground surface. A classification of say development is provided based on the displacement-time data

Verification of land-atmosphere coupling in forecast models, reanalyses and land surface models using flux site observations.

Science.gov (United States)

Dirmeyer, Paul A; Chen, Liang; Wu, Jiexia; Shin, Chul-Su; Huang, Bohua; Cash, Benjamin A; Bosilovich, Michael G; Mahanama, Sarith; Koster, Randal D; Santanello, Joseph A; Ek, Michael B; Balsamo, Gianpaolo; Dutra, Emanuel; Lawrence, D M

2018-02-01

We confront four model systems in three configurations (LSM, LSM+GCM, and reanalysis) with global flux tower observations to validate states, surface fluxes, and coupling indices between land and atmosphere. Models clearly under-represent the feedback of surface fluxes on boundary layer properties (the atmospheric leg of land-atmosphere coupling), and may over-represent the connection between soil moisture and surface fluxes (the terrestrial leg). Models generally under-represent spatial and temporal variability relative to observations, which is at least partially an artifact of the differences in spatial scale between model grid boxes and flux tower footprints. All models bias high in near-surface humidity and downward shortwave radiation, struggle to represent precipitation accurately, and show serious problems in reproducing surface albedos. These errors create challenges for models to partition surface energy properly and errors are traceable through the surface energy and water cycles. The spatial distribution of the amplitude and phase of annual cycles (first harmonic) are generally well reproduced, but the biases in means tend to reflect in these amplitudes. Interannual variability is also a challenge for models to reproduce. Our analysis illuminates targets for coupled land-atmosphere model development, as well as the value of long-term globally-distributed observational monitoring.

Comparison of optimum tilt angles of solar collectors determined at yearly, seasonal and monthly levels

International Nuclear Information System (INIS)

Despotovic, Milan; Nedic, Vladimir

2015-01-01

Highlights: • Optimum yearly, biannual, seasonal, monthly, and daily tilt angles were found. • Energy collected per square meter is compared for ten different scenarios. • Four seasonal scenarios and two biannual scenarios were considered. • It is sufficient to adjust tilt angles only twice per year. - Abstract: The amount of energy that is transformed in solar collector depends on its tilt angle with respect to horizontal plane and orientation of the collector. In this article the optimum tilt angle of solar collectors for Belgrade, which is located at the latitude of 44°47′N is determined. The optimum tilt angle was found by searching for the values for which the solar radiation on the collector surface is maximum for a particular day or a specific period. In that manner the yearly, biannual, seasonal, monthly, fortnightly, and daily optimum tilt angles are determined. Annually collected energy per square meter of tilted surface is compared for ten different scenarios. In addition, these optimum tilt angles are used to calculate the amount of energy on the surface of PV panels that could be installed at the roof of the building. The results show that for observed case study placing the panels at yearly, seasonal and monthly optimum tilt angles, would yield increasing yearly amount of collected energy by factor of 5.98%, 13.55%, and 15.42% respectively compared to energy that could be collected by putting the panels at current roofs’ surface angles

Three-dimensional numerical simulation of crown spike due to coupling effect between bubbles and free surface

International Nuclear Information System (INIS)

Han Rui; Zhang A-Man; Li Shuai

2014-01-01

The motion of gas bubbles beneath a free surface will lead to a spike of fluid on the free surface. The distance of the bubbles to the free surface is the key factor to different phenomena. When the inception distance varies in some range, crown phenomenon would happen after the impact of weak buoyancy bubbles, so this kind of spike is defined as crown spike in the present paper. Based on potential flow theory, a three-dimensional numerical model is established to simulate the motion of the free-surface spike generated by one bubble or a horizontal line of two in-phase bubbles. After the downward jet formed near the end of the collapse phase, the simulation of the free surface is performed to study the crown spike without regard to the toroidal bubble's effect. Calculations about the interaction between one bubble and free surface agree well with the experimental results conducted with a high-speed camera, and relative error is within 15%. Crown spike in both single- and two-bubble cases are simulated numerically. Different features and laws of the motion of crown spike, depending on the bubble-boundary distances and the inter-bubble distances, have been investigated

Mitigation of upward and downward vertical displacement event heat loads with upper or lower massive gas injection in DIII-D

Science.gov (United States)

Hollmann, E. M.; Commaux, N.; Eidietis, N. W.; Lasnier, C. J.; Moyer, R. A.; Parks, P. B.; Shiraki, D.

2015-10-01

Intentionally triggered upward and downward vertical displacement events (VDEs) leading to disruptions were pre-emptively mitigated with neon massive gas injection (MGI) coming from either above or below the plasma. Global indicators of disruption mitigation effectiveness (conducted heat loads, radiated power, and vessel motion) do not show a clear improvement when mitigating with the gas jet located closer to the VDE impact area. A clear trend of improved mitigation is observed for earlier MGI timing relative to the VDE impact time. The plasma edge magnetic perturbation is seen to lock to a preferential phase during the VDE thermal quench, but this phase is not clearly matched by preliminary attempts to fit to the conducted heat load phase. Clear indications of plasma infra-red (IR) emission are observed both before and during the disruptions. This IR emission can affect calculation of disruption heat loads; here, the time decay of post-disruption IR signals is used to correct for this effect.

Mitigation of upward and downward vertical displacement event heat loads with upper or lower massive gas injection in DIII-D

International Nuclear Information System (INIS)

Hollmann, E. M.; Moyer, R. A.; Commaux, N.; Shiraki, D.; Eidietis, N. W.; Parks, P. B.; Lasnier, C. J.

2015-01-01

Intentionally triggered upward and downward vertical displacement events (VDEs) leading to disruptions were pre-emptively mitigated with neon massive gas injection (MGI) coming from either above or below the plasma. Global indicators of disruption mitigation effectiveness (conducted heat loads, radiated power, and vessel motion) do not show a clear improvement when mitigating with the gas jet located closer to the VDE impact area. A clear trend of improved mitigation is observed for earlier MGI timing relative to the VDE impact time. The plasma edge magnetic perturbation is seen to lock to a preferential phase during the VDE thermal quench, but this phase is not clearly matched by preliminary attempts to fit to the conducted heat load phase. Clear indications of plasma infra-red (IR) emission are observed both before and during the disruptions. This IR emission can affect calculation of disruption heat loads; here, the time decay of post-disruption IR signals is used to correct for this effect

Estimation of monthly-mean daily global solar radiation based on MODIS and TRMM products

International Nuclear Information System (INIS)

Qin, Jun; Chen, Zhuoqi; Yang, Kun; Liang, Shunlin; Tang, Wenjun

2011-01-01

Global solar radiation (GSR) is required in a large number of fields. Many parameterization schemes are developed to estimate it using routinely measured meteorological variables, since GSR is directly measured at a limited number of stations. Even so, meteorological stations are sparse, especially, in remote areas. Satellite signals (radiance at the top of atmosphere in most cases) can be used to estimate continuous GSR in space. However, many existing remote sensing products have a relatively coarse spatial resolution and these inversion algorithms are too complicated to be mastered by experts in other research fields. In this study, the artificial neural network (ANN) is utilized to build the mathematical relationship between measured monthly-mean daily GSR and several high-level remote sensing products available for the public, including Moderate Resolution Imaging Spectroradiometer (MODIS) monthly averaged land surface temperature (LST), the number of days in which the LST retrieval is performed in 1 month, MODIS enhanced vegetation index, Tropical Rainfall Measuring Mission satellite (TRMM) monthly precipitation. After training, GSR estimates from this ANN are verified against ground measurements at 12 radiation stations. Then, comparisons are performed among three GSR estimates, including the one presented in this study, a surface data-based estimate, and a remote sensing product by Japan Aerospace Exploration Agency (JAXA). Validation results indicate that the ANN-based method presented in this study can estimate monthly-mean daily GSR at a spatial resolution of about 5 km with high accuracy.

Metal-silicate fractionation in the surface dust layers of accreting planetesimals: Implications for the formation of ordinary chondrites and the nature of asteroid surfaces

Science.gov (United States)

Huang, Shaoxiong; Akridge, Glen; Sears, Derek W. G.

Some of the most primitive solar system materials available for study in the laboratory are the ordinary chondrites, the largest meteorite class. The size and distribution of the chondrules (silicate beads) and metal, which leads to the definition of the H, L, and LL classes, suggest sorting before or during aggregation. We suggest that meteorite parent bodies (probably asteroids) had thick dusty surfaces during their early evolution that were easily mobilized by gases evolving from their interiors. Density and size sorting would have occurred in the surface layers as the upward drag forces of the gases (mainly water) acted against the downward force of gravity. The process is analogous to the industrially important process of fluidization and sorting in pyroclastic volcanics. We calculate that gas flow velocities and gas fluxes for the regolith of an asteroid-sized object heated by the impact of accreting objects or by 26Al would have been sufficient for fluidization. It can also explain, quantitatively in some cases, the observed metal-silicate sorting of ordinary chondrites, which has long been ascribed to processes occurring in the primordial solar nebula. Formation of the chondrites in the thick dynamic regolith is consistent with the major properties of chondritic meteorites (i.e., redox state, petrologic type, cooling rate, matrix abundance). These ideas have implications for the nature of asteroid surfaces and the virtual lack of asteroids with ordinary chondrite-like surfaces.

Comparison of observed and modeled cloud-free longwave downward radiation (2010–2016 at the high mountain BSRN Izaña station

Directory of Open Access Journals (Sweden)

R. D. García

2018-06-01

Full Text Available A 7-year (2010–2016 comparison study between measured and simulated longwave downward radiation (LDR under cloud-free conditions was performed at the Izaña Atmospheric Observatory (IZO, Spain. This analysis encompasses a total of 2062 cases distributed approximately evenly between day and night. Results show an excellent agreement between Baseline Surface Radiation Network (BSRN measurements and simulations with libRadtran V2.0.1 and MODerate resolution atmospheric TRANsmission model (MODTRAN V6 radiative transfer models (RTMs. Mean bias (simulated − measured of  <  1.1 % and root mean square of the bias (RMS of  <  1 % are within the instrumental error (2 %. These results highlight the good agreement between the two RTMs, proving to be useful tools for the quality control of LDR observations and for detecting temporal drifts in field instruments. The standard deviations of the residuals, associated with the RTM input parameters uncertainties are rather small, 0.47 and 0.49 % for libRadtran and MODTRAN, respectively, at daytime, and 0.49 to 0.51 % at night-time. For precipitable water vapor (PWV  >  10 mm, the observed night-time difference between models and measurements is +5 W m−2 indicating a scale change of the World Infrared Standard Group of Pyrgeometers (WISG, which serves as reference for atmospheric longwave radiation measurements. Preliminary results suggest a possible impact of dust aerosol on infrared radiation during daytime that might not be correctly parametrized by the models, resulting in a slight underestimation of the modeled LDR, of about −3 W m−2, for relatively high aerosol optical depth (AOD  >  0.20.

International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 2 Daily

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 1 Daily

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

Efficiency of photodynamic therapy in the treatment of peri-implantitis: A three-month randomized controlled clinical trial

Directory of Open Access Journals (Sweden)

Rakašević Dragana

2016-01-01

Full Text Available Introduction. Peri-implantitis is an inflammatory lesion of peri-implant tissues. Eradication of the causative bacteria and decontamination of the implant surface is essential in achieving predictable and stabile clinical results. Photodynamic therapy (PDT is non-invasive adjuvant therapeutic method to surgery in the treatment of bacterial infection. Objective. The aim of this study was to evaluate early clinical and microbiological outcomes of periimplantitis after surgical therapy with adjuvant PDT. Methods. Fifty-two diagnosed peri-implantitis sites were divided into two groups. PDT was used for decontamination of implant surface in the study group; in the control group, chlorhexidine gel (CHX followed by saline irrigation was applied. Several clinical parameters were recorded before the treatment (baseline values and three months after surgical treatment. Samples for microbiological identification were collected before therapy, during the surgical therapy (before and after decontamination of implant surface, and three months thereafter, and analyzed with identification systems using biochemical analysis. Results. The use of PDT resulted in significant decrease of bleeding on probing in comparison to CHX (p < 0.001. It showed significant decontamination of implant surfaces with complete elimination of anaerobic bacteria immediately after surgical procedure and three months later. Conclusion. The results indicate that PDT can be used as an adjuvant therapy to surgery for decontamination of implant surface and surrounding peri-implant tissues within the treatment of peri-implantitis. [Projekat Ministarstva nauke Republike Srbije, br. 41008

Charged plate in asymmetric electrolytes: One-loop renormalization of surface charge density and Debye length due to ionic correlations.

Science.gov (United States)

Ding, Mingnan; Lu, Bing-Sui; Xing, Xiangjun

2016-10-01

Self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a m:-n electrolyte. A perturbation series is developed in terms of g=4πκb, where band1/κ are Bjerrum length and bare Debye length, respectively. To the zeroth order, we obtain the nonlinear Poisson-Boltzmann theory. For asymmetric electrolytes (m≠n), the first order (one-loop) correction to mean potential contains a secular term, which indicates the breakdown of the regular perturbation method. Using a renormalizaton group transformation, we remove the secular term and obtain a globally well-behaved one-loop approximation with a renormalized Debye length and a renormalized surface charge density. Furthermore, we find that if the counterions are multivalent, the surface charge density is renormalized substantially downwards and may undergo a change of sign, if the bare surface charge density is sufficiently large. Our results agrees with large MC simulation even when the density of electrolytes is relatively high.

NLDAS Noah Land Surface Model L4 Monthly 0.125 x 0.125 degree V002

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains a series of land surface parameters simulated from the Noah land-surface model (LSM) for Phase 2 of the North American Land Data Assimilation...

Investigation on Surface Polarization of Al2O3-capped GaN/AlGaN/GaN Heterostructure by Angle-Resolved X-ray Photoelectron Spectroscopy.

Science.gov (United States)

Duan, Tian Li; Pan, Ji Sheng; Wang, Ning; Cheng, Kai; Yu, Hong Yu

2017-08-17

The surface polarization of Ga-face gallium nitride (GaN) (2 nm)/AlGaN (22 nm)/GaN channel (150 nm)/buffer/Si with Al 2 O 3 capping layer is investigated by angle-resolved X-ray photoelectron spectroscopy (ARXPS). It is found that the energy band varies from upward bending to downward bending in the interface region, which is believed to be corresponding to the polarization variation. An interfacial layer is formed between top GaN and Al 2 O 3 due to the occurrence of Ga-N bond break and Ga-O bond forming during Al 2 O 3 deposition via the atomic layer deposition (ALD). This interfacial layer is believed to eliminate the GaN polarization, thus reducing the polarization-induced negative charges. Furthermore, this interfacial layer plays a key role for the introduction of the positive charges which lead the energy band downward. Finally, a N 2 annealing at 400 °C is observed to enhance the interfacial layer growth thus increasing the density of positive charges.

'Downward control' of the mean meridional circulation and temperature distribution of the polar winter stratosphere

Science.gov (United States)

Garcia, Rolando R.; Boville, Byron A.

1994-01-01

According to the 'downward control' principle, the extratropical mean vertical velocity on a given pressure level is approximately proportional to the meridional gradient of the vertically integrated zonal force per unit mass exerted by waves above that level. In this paper, a simple numerical model that includes parameterizations of both planetary and gravity wave breaking is used to explore the influence of gravity wave breaking in the mesosphere on the mean meridional circulation and temperature distribution at lower levels in the polar winter stratosphere. The results of these calculations suggest that gravity wave drag in the mesosphere can affect the state of the polar winter stratosphere down to altitudes below 30 km. The effect is most important when planetary wave driving is relatively weak: that is, during southern winter and in early northern winter. In southern winter, downwelling weakens by a factor of 2 near the stratospause and by 20% at 30 km when gravity wave drag is not included in the calculations. As a consequence, temperatures decrease considerably throughout the polar winter stratosphere (over 20 K above 40 km and as much as 8 K at 30 km, where the effect is enhanced by the long radiative relaxation timescale). The polar winter states obtained when gravity wave drag is omitted in this simple model resemble the results of simulations with some general circulation models and suggest that some of the shortcomings of the latter may be due to a deficit in mesospheric momentum deposition by small-scale gravity waves.

Tracers confirm downward mixing of Tyrrhenian Sea upper waters associated with the Eastern Mediterranean Transient

Directory of Open Access Journals (Sweden)

W. Roether

2011-01-01

Full Text Available Observations of tritium and ³He in the Tyrrhenian Sea, 1987–2009, confirm the enhanced vertical mixing of intermediate waters into the deep waters that has been noted and associated with the Eastern Mediterranean Transient in previous studies. Our evidence for the mixing rests on increasing tracer concentrations in the Tyrrhenian deep waters, accompanied by decreases in the upper waters, which are supplied from the Eastern Mediterranean. The downward transfer is particularly evident between 1987 and 1997. Later on, information partly rests on increasing tritium-³He ages; here we correct the observed ³He for contributions released from the ocean floor. The Tyrrhenian tracer distributions are fully compatible with data upstream of the Sicily Strait and in the Western Mediterranean. The tracer data show that mixing reached to the bottom and confirm a cyclonic nature of the deep water circulation in the Tyrrhenian. They furthermore indicate that horizontal homogenization of the deep waters occurs on a time scale of roughly 5 years. Various features point to a reduced impact of Western Mediterranean Deep Water (WMDW in the Tyrrhenian during the enhanced-mixing period. This is an important finding because it implies less upward mixing of WMDW, which has been named a major process to enable the WMDW to leave the Mediterranean via the Gibraltar Strait. On the other hand, the TDW outflow for several years represented a major influx of enhanced salinity and density waters into the deep-water range of the Western Mediterranean.

Natural gas monthly

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

The Natural Gas Monthly highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the Natural Gas Monthly features articles designed to assist readers in using and interpreting natural gas information.

TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958-2015

Science.gov (United States)

Abatzoglou, John T.; Dobrowski, Solomon Z.; Parks, Sean A.; Hegewisch, Katherine C.

2018-01-01

We present TerraClimate, a dataset of high-spatial resolution (1/24°, ~4-km) monthly climate and climatic water balance for global terrestrial surfaces from 1958-2015. TerraClimate uses climatically aided interpolation, combining high-spatial resolution climatological normals from the WorldClim dataset, with coarser resolution time varying (i.e., monthly) data from other sources to produce a monthly dataset of precipitation, maximum and minimum temperature, wind speed, vapor pressure, and solar radiation. TerraClimate additionally produces monthly surface water balance datasets using a water balance model that incorporates reference evapotranspiration, precipitation, temperature, and interpolated plant extractable soil water capacity. These data provide important inputs for ecological and hydrological studies at global scales that require high spatial resolution and time varying climate and climatic water balance data. We validated spatiotemporal aspects of TerraClimate using annual temperature, precipitation, and calculated reference evapotranspiration from station data, as well as annual runoff from streamflow gauges. TerraClimate datasets showed noted improvement in overall mean absolute error and increased spatial realism relative to coarser resolution gridded datasets.

Experimental study of gas entrainment from surface swirl

Energy Technology Data Exchange (ETDEWEB)

Moudjed, B., E-mail: brahim.moudjed@cea.fr; Excoffon, J.; Riva, R.; Rossi, L., E-mail: lionel.rossi@cea.fr

2016-12-15

Gas entrainment from surface swirls is characterized using water experiments. A free surface shear flow is generated in an open channel flow. A suction nozzle is set at the bottom of the test section to induce a downward flow and provoke gas entrainment. An important originality of these experiments is the possibility to change the inlet condition so as to generate different turbulent shear flows. This is done by adding obstacles of different sizes and shapes at the end of a flat plate separating the inlet flow from a “stagnant” water area. Velocity fields and profiles, measured with the PIV technique, are provided both to describe the inlet conditions corresponding to various geometries and flow rates, and to characterize the temporal average shear flow generated within the centre part of the channel. Gas entrainment mappings are established from direct observations of the different flow configurations. These new results show that the threshold for the suction velocities required to entrain gas are similar for the configurations with small obstacles and the flat plate configuration triggering a standard shear flow. Increasing the size of the obstacles promotes gas entrainment and reduces the threshold values of the suction velocity to trigger gas entrainment. Shadowgraphy with image processing is used to present new results characterizing the geometrical properties of surface swirls and the quantity of gas entrained. Inlet configurations with obstacles generate larger surface swirls which move upstream from the suction nozzle centre whereas they are situated downstream with the flat plate configuration. Moreover, dimensionless power laws are found to be good approximations for the surface swirl width and the quantity of gas entrained. In addition to provide new insights about gas entrainment in analytical configurations relevant to Sodium cooled fast nuclear reactor, these results should provide different test cases for the validation of MCFD codes.

Monthly Weather Review

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Supplements to the Monthly Weather Review publication. The Weather Bureau published the Monthly weather review Supplement irregularly from 1914 to 1949. The...

Characterization of the near-surface radionuclide contamination associated with the bathtub effect at Solid Waste Storage Area 4, Oak Ridge National Laboratory, Tennessee

International Nuclear Information System (INIS)

Melroy, L.A.; Huff, D.D.; Farrow, N.D.

1986-06-01

Solid Waste Storage Area 4 (SWSA-4) at the Oak Ridge National Laboratory (ORNL) was studied to determine the extent of near-surface radionuclide contamination associated with the bathtub effect in low-lying trenches. A surface survey of the low-elevation portion of the burial ground was conducted to identify areas where the bathtub effect had resulted in surface contamination. Using this initial survey as a guide, 15 soil cores, each approximately 3 m deep, were taken to determine the depth to which contamination had spread and to help identify an contamination plumes. Results showed that two areas of surface radionuclide contamination exist, one located between the western end of the SWSA-4 tributary and the edge of the burial ground, the other located just north of the tributary below the central paved runoff channel. In addition, some downward migration of the solutes has occurred. However, the penetration depth for 90 Sr seems to be generally less than 2.7 m

Seasonal and Interannual Variation in Energy Balance in the Semiarid Grassland Area of China

Directory of Open Access Journals (Sweden)

Qun’ou Jiang

2015-01-01

Full Text Available Near surface energy budget changes have been proved to be induced by the land cover conversion through changing the surface physical properties, which can further impact the regional climate change. This study applies the DLS model to simulate the land cover under the business as usual (BAU scenario and then analyses the seasonal and interannual variation of energy balance in the semiarid grassland area of China based on the simulated land cover with the Weather Research and Forecasting (WRF model. The results indicate that the grassland will show a growing trend under the BAU scenario. Downward long wave radiation and downward short wave radiation will all have small-scale increase with time going by, while the surface net radiation will decrease from 2030 to 2050. However, there is obvious seasonal variation. Summer has the highest downward long wave radiation and downward short wave radiation, followed by spring and autumn. The lowest are in winter. As for the net surface radiation, there is obvious decrease in southeast of study area due to returning cropland to grassland. Those research conclusions can offer valuable information for the land use planning and relieving the effects of land cover change on climate change at the semiarid grassland area.

Surface Meteorology and Solar Energy

Data.gov (United States)

National Aeronautics and Space Administration — Surface Meteorology and Solar Energy data - over 200 satellite-derived meteorology and solar energy parameters, monthly averaged from 22 years of data, global solar...

TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958–2015

OpenAIRE

Abatzoglou, John T.; Dobrowski, Solomon Z.; Parks, Sean A.; Hegewisch, Katherine C.

2018-01-01

We present TerraClimate, a dataset of high-spatial resolution (1/24°, ~4-km) monthly climate and climatic water balance for global terrestrial surfaces from 1958–2015. TerraClimate uses climatically aided interpolation, combining high-spatial resolution climatological normals from the WorldClim dataset, with coarser resolution time varying (i.e., monthly) data from other sources to produce a monthly dataset of precipitation, maximum and minimum temperature, wind speed, vapor pressure, and sol...

Extended Reconstructed Sea Surface Temperature (ERSST), Version 4

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature analysis on a 2x2 degree grid derived from the...

Linear theory period ratios for surface helium enhanced double-mode Cepheids

International Nuclear Information System (INIS)

Cox, A.N.; Hodson, S.W.; King, D.S.

1979-01-01

Linear nonadiabatic theory period ratios for models of double-mode Cepheids with their two periods between 1 and 7 days have been computed, assuming differing amounts and depths of surface helium enhancement. Evolution theory masses and luminosities are found to be consistent with the observed periods. All models give Pi 1 /Pi 0 approx. =0.70 as observed for the 11 known variables, contrary to previous theoretical conclusions. The composition structure that best fits the period ratios has the helium mass fraction in the outer 10 -3 of the stellar mass (T< or =250,000 K) as 0.65, similar to a previous model for the triple-mode pulsator AC And. This enrichment can be established by a Cepheid wind and downward inverted μ gradient instability mixing in the lifetime of these low-mass classical Cepheids

Vertical structure of turbulence in offshore flow during RASEX

DEFF Research Database (Denmark)

Mahrt, L.; Vickers, D.; Edson, J.

2001-01-01

and dissipation. However, weakly stable and weakly unstable cases exhibit completely different vertical structure. With flow of warm air from land over cooler water, modest buoyancy destruction of turbulence and reduced shear generation of turbulence over the less rough sea surface cause the turbulence to rapidly...... with height and downward transport of turbulence energy toward the surface. With flow of cool air over a warmer sea surface, a convective internal boundary layer develops downstream from the coast. An overlying relatively thick layer of downward buoyancy flux (virtual temperature flux) is sometimes maintained...

Iterative discrete ordinates solution of the equation for surface-reflected radiance

Science.gov (United States)

Radkevich, Alexander

2017-11-01

This paper presents a new method of numerical solution of the integral equation for the radiance reflected from an anisotropic surface. The equation relates the radiance at the surface level with BRDF and solutions of the standard radiative transfer problems for a slab with no reflection on its surfaces. It is also shown that the kernel of the equation satisfies the condition of the existence of a unique solution and the convergence of the successive approximations to that solution. The developed method features two basic steps: discretization on a 2D quadrature, and solving the resulting system of algebraic equations with successive over-relaxation method based on the Gauss-Seidel iterative process. Presented numerical examples show good coincidence between the surface-reflected radiance obtained with DISORT and the proposed method. Analysis of contributions of the direct and diffuse (but not yet reflected) parts of the downward radiance to the total solution is performed. Together, they represent a very good initial guess for the iterative process. This fact ensures fast convergence. The numerical evidence is given that the fastest convergence occurs with the relaxation parameter of 1 (no relaxation). An integral equation for BRDF is derived as inversion of the original equation. The potential of this new equation for BRDF retrievals is analyzed. The approach is found not viable as the BRDF equation appears to be an ill-posed problem, and it requires knowledge the surface-reflected radiance on the entire domain of both Sun and viewing zenith angles.

Nitride surface passivation of GaAs nanowires: impact on surface state density.

Science.gov (United States)

Alekseev, Prokhor A; Dunaevskiy, Mikhail S; Ulin, Vladimir P; Lvova, Tatiana V; Filatov, Dmitriy O; Nezhdanov, Alexey V; Mashin, Aleksander I; Berkovits, Vladimir L

2015-01-14

Surface nitridation by hydrazine-sulfide solution, which is known to produce surface passivation of GaAs crystals, was applied to GaAs nanowires (NWs). We studied the effect of nitridation on conductivity and microphotoluminescence (μ-PL) of individual GaAs NWs using conductive atomic force microscopy (CAFM) and confocal luminescent microscopy (CLM), respectively. Nitridation is found to produce an essential increase in the NW conductivity and the μ-PL intensity as well evidence of surface passivation. Estimations show that the nitride passivation reduces the surface state density by a factor of 6, which is of the same order as that found for GaAs/AlGaAs nanowires. The effects of the nitride passivation are also stable under atmospheric ambient conditions for six months.

NOAA Extended Reconstructed Sea Surface Temperature (ERSST), Version 5

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature dataset derived from the International...

The Global Character of the Flux of Downward Longwave Radiation

Science.gov (United States)

Stephens, Graeme L.; Wild, Martin; Stackhouse, Paul W., Jr.; L'Ecuyer, Tristan; Kato, Seiji; Henderson, David S.

2012-01-01

Four different types of estimates of the surface downwelling longwave radiative flux (DLR) are reviewed. One group of estimates synthesizes global cloud, aerosol, and other information in a radiation model that is used to calculate fluxes. Because these synthesis fluxes have been assessed against observations, the global-mean values of these fluxes are deemed to be the most credible of the four different categories reviewed. The global, annual mean DLR lies between approximately 344 and 350 W/sq m with an error of approximately +/-10 W/sq m that arises mostly from the uncertainty in atmospheric state that governs the estimation of the clear-sky emission. The authors conclude that the DLR derived from global climate models are biased low by approximately 10 W/sq m and even larger differences are found with respect to reanalysis climate data. The DLR inferred from a surface energy balance closure is also substantially smaller that the range found from synthesis products suggesting that current depictions of surface energy balance also require revision. The effect of clouds on the DLR, largely facilitated by the new cloud base information from the CloudSat radar, is estimated to lie in the range from 24 to 34 W/sq m for the global cloud radiative effect (all-sky minus clear-sky DLR). This effect is strongly modulated by the underlying water vapor that gives rise to a maximum sensitivity of the DLR to cloud occurring in the colder drier regions of the planet. The bottom of atmosphere (BOA) cloud effect directly contrast the effect of clouds on the top of atmosphere (TOA) fluxes that is maximum in regions of deepest and coldest clouds in the moist tropics.

Relationship between ice water path and downward longwave radiation for clouds optically thin in the infrared: Observations and model calculations

Science.gov (United States)

Uttal, Taneil; Matrosov, Sergey Y.; Snider, Jack B.; Kropfli, Robert A.

1994-01-01

A vertically pointing 3.2-cm radar is used to observe altostratus and cirrus clouds as they pass overhead. Radar reflectivities are used in combination with an empirical Z(sub i)-IWC (ice water content) relationship developed by Sassen (1987) to parameterize IWC, which is then integrated to obtain estimates of ice water path (IWP). The observed dataset is segregated into all-ice and mixed-phase periods using measurements of integrated liquid water paths (LWP) detected by a collocated, dual-channel microwave radiometer. The IWP values for the all ice periods are compared to measurements of infrared (IR) downward fluxes measured by a collocated narrowband (9.95-11.43 microns) IR radiometer, which results in scattergrams representing the observed dependence of IR fluxes on IWP. A two-stream model is used to calculate the infrared fluxes expected from ice clouds with boundary conditions specified by the actual clouds, and similar curves relating IWP and infrared fluxes are obtained. The model and observational results suggest that IWP is one of the primary controls on infrared thermal fluxes for ice clouds.

Simulation optimization of filament parameters for uniform depositions of diamond films on surfaces of ultra-large circular holes

Energy Technology Data Exchange (ETDEWEB)

Wang, Xinchang, E-mail: wangxinchangz@163.com; Shen, Xiaotian; Sun, Fanghong; Shen, Bin

2016-12-01

Highlights: • A verified simulation model using a novel filament arrangement is constructed. • Influences of filament parameters are clarified. • A coefficient between simulated and experimental results is proposed. • Orthogonal simulations are adopted to optimize filament parameters. • A general filament arrangement suitable for different conditions is determined. - Abstract: Chemical vapor deposition (CVD) diamond films have been widely applied as protective coatings on varieties of anti-frictional and wear-resistant components, owing to their excellent mechanical and tribological properties close to the natural diamond. In applications of some components, the inner hole surface will serve as the working surface that suffers severe frictional or erosive wear. It is difficult to realize uniform depositions of diamond films on surfaces of inner holes, especially ultra-large inner holes. Adopting a SiC compact die with an aperture of 80 mm as an example, a novel filament arrangement with a certain number of filaments evenly distributed on a circle is designed, and specific effects of filament parameters, including the filament number, arrangement direction, filament temperature, filament diameter, circumradius and the downward translation, on the substrate temperature distribution are studied by computational fluid dynamics (CFD) simulations based on the finite volume method (FVM), adopting a modified computational model well consistent with the actual deposition environment. Corresponding temperature measurement experiments are also conducted to verify the rationality of the computational model. From the aspect of depositing uniform boron-doped micro-crystalline, undoped micro-crystalline and undoped fine-grained composite diamond (BDM-UMC-UFGCD) film on such the inner hole surface, filament parameters as mentioned above are accurately optimized and compensated by orthogonal simulations. Moreover, deposition experiments adopting compensated optimized

Anti-parallel polarization switching in a triglycine sulfate organic ferroelectric insulator: The role of surface charges

Science.gov (United States)

Ma, He; Wu, Zhuangchun; Peng, Dongwen; Wang, Yaojin; Wang, Yiping; Yang, Ying; Yuan, Guoliang

2018-04-01

Four consecutive ferroelectric polarization switchings and an abnormal ring-like domain pattern can be introduced by a single tip bias of a piezoresponse force microscope in the (010) triglycine sulfate (TGS) crystal. The external electric field anti-parallel to the original polarization induces the first polarization switching; however, the surface charges of TGS can move toward the tip location and induce the second polarization switching once the tip bias is removed. The two switchings allow a ring-like pattern composed of the central domain with downward polarization and the outer domain with upward polarization. Once the two domains disappear gradually as a result of depolarization, the other two polarization switchings occur one by one at the TGS where the tip contacts. However, the backswitching phenomenon does not occur when the external electric field is parallel to the original polarization. These results can be explained according to the surface charges instead of the charges injected inside.

Downward carbon transport in a 2000-year rice paddy soil chronosequence traced by radiocarbon measurements

International Nuclear Information System (INIS)

Bräuer, T.; Grootes, P.M.; Nadeau, M.-J.; Andersen, N.

2013-01-01

Paddy and non-paddy soils from a chronosequence of 50–2000 years of agricultural use, developed on former estuarine sediments of the Yangtze River, were sampled near Cixi, Zhejiang Province, China, in the framework of the Research Unit “Biogeochemistry of paddy soil evolution” of the German Research Foundation (DFG). In addition samples of Yangtze River estuarine sediments were obtained. The parent sediment shows a fairly homogeneous composition with ca. 0.3% TOC and a 14 C concentration of ca. 50 pMC. After being diked-in, gradients in soil organic carbon and 14 C concentration develop under the influence of vegetation and cultivation. In the non-paddy soil, a 14 C gradient with concentration decreasing with increasing depth from modern (>100 pMC) to original sediment values around 50 pMC is already established after 50 years and can also be observed in the older sites. In contrast, the 50 years old paddy soil shows organic carbon and 14 C enrichment only in the A-horizon and a nearly constant TOC and 14 C stock of original sediment below the plough pan. To test the basic approach that the soil profile development started on homogeneous sediment, an isotope and mass balance calculation was used. The results show a quite similar age composition of different sample sites. Paddy rice cultivation quickly leads to a dense plough pan, which seriously reduces, but not totally prevents, downward transport of organic matter. The equilibrium times for TOC and 14 C in paddy soil profiles are short (decades) in the topsoil and in the order of centuries in the subsoil, underlining the dynamic character of soil organic carbon.

Long-term follow-up after maxillary distraction osteogenesis in growing children with cleft lip and palate.

Science.gov (United States)

Huang, Chiung-Shing; Harikrishnan, Pandurangan; Liao, Yu-Fang; Ko, Ellen W C; Liou, Eric J W; Chen, Philip K T

2007-05-01

To evaluate the changes in maxillary position after maxillary distraction osteogenesis in six growing children with cleft lip and palate. Retrospective, longitudinal study on maxillary changes at A point, anterior nasal spine, posterior nasal spine, central incisor, and first molar. The University Hospital Craniofacial Center. Cephalometric radiographs were used to measure the maxillary position immediately after distraction, at 6 months, and more than 1 year after distraction. After maxillary distraction with a rigid external distraction device, the maxilla (A point) on average moved forward 9.7 mm and downward 3.5 mm immediately after distraction, moved backward 0.9 mm and upward 2.0 mm after 6 months postoperatively, and then moved further backward 2.3 mm and downward 6.8 mm after more than 1 year from the predistraction position. In most cases, maxilla moved forward at distraction and started to move backward until 1 year after distraction, but remained forward, as compared with predistraction position. Maxilla also moved downward during distraction and upward in 6 months, but started descending in 1 year. There also was no further forward growth of the maxilla after distraction in growing children with clefts.

Determination of the surface band bending in InxGa1−xN films by hard x-ray photoemission spectroscopy

Directory of Open Access Journals (Sweden)

Mickael Lozac'h, Shigenori Ueda, Shitao Liu, Hideki Yoshikawa, Sang Liwen, Xinqiang Wang, Bo Shen, Kazuaki Sakoda, Keisuke Kobayashi and Masatomo Sumiya

2013-01-01

Full Text Available Core-level and valence band spectra of InxGa1−xN films were measured using hard x-ray photoemission spectroscopy (HX-PES. Fine structure, caused by the coupling of the localized Ga 3d and In 4d with N 2s states, was experimentally observed in the films. Because of the large detection depth of HX-PES (~20 nm, the spectra contain both surface and bulk information due to the surface band bending. The InxGa1−xN films (x = 0–0.21 exhibited upward surface band bending, and the valence band maximum was shifted to lower binding energy when the mole fraction of InN was increased. On the other hand, downward surface band bending was confirmed for an InN film with low carrier density despite its n-type conduction. Although the Fermi level (EF near the surface of the InN film was detected inside the conduction band as reported previously, it can be concluded that EF in the bulk of the film must be located in the band gap below the conduction band minimum.

Oxidation of FGD-CaSO{sub 3} and effect on soil chemical properties when applied to the soil surface

Energy Technology Data Exchange (ETDEWEB)

Liming Chen; Cliff Ramsier; Jerry Bigham; Brian Slater; David Kost; Yong Bok Lee; Warren A. Dick [Ohio State University, Wooster, OH (United States). School of Environment and Natural Resources

2009-07-15

Use of high-sulfur coal for power generation in the United States requires the removal of sulfur dioxide (SO{sub 2}) produced during burning in order to meet clean air regulations. If SO{sub 2} is removed from the flue gas using a wet scrubber without forced air oxidation, much of the S product created will be sulfite (SO{sub 3}{sup 2-}). Plants take up S in the form of sulfate (SO{sub 2}{sup 2-}). Sulfite may cause damage to plant roots, especially in acid soils. For agricultural uses, it is thought that SO{sub 4}{sup 2-} in flue gas desulfurization (FGD) products must first oxidize to SO{sub 4}{sup 2-} in soils before crops are planted. However, there is little information about the oxidation of SO{sub 3}{sup 2-} in FGD product to SO{sub 4}{sup 2-} under field conditions. An FGD-CaSO{sub 3} was applied at rates of 0, 1.12, and 3.36 Mg ha{sup -1} to the surface of an agricultural soil (Wooster silt loam, Oxyaquic Fragiudalf). The SO{sub 4}{sup 2-} in the surface soil (0-10 cm) was analyzed on days 3, 7, 17, 45, and 61. The distribution of SO{sub 4}{sup 2-} and Ca in the 0-90 cm soil layer was also determined on day 61. Results indicated that SO{sub 3}{sup 2-} in the FGD-CaSO{sub 3} rapidly oxidized to SO{sub 4}{sup 2-} on the field surface during the first week and much of the SO{sub 4}{sup 2-} and Ca moved downward into the 0-50 cm soil layer during the experimental period of two months. It is safe to grow plants in soil treated with FGD-CaSO{sub 3} if the application is made at least three days to several weeks before planting. 20 refs., 6 figs., 4 tabs.

Surface changes of enamel after brushing with charcoal toothpaste

Science.gov (United States)

Pertiwi, U. I.; Eriwati, Y. K.; Irawan, B.

2017-08-01

The aim of this study was to determine the surface roughness changes of tooth enamel after brushing with charcoal toothpaste. Thirty specimens were brushed using distilled water (the first group), Strong® Formula toothpaste (the second group), and Charcoal® Formula toothpaste for four minutes and 40 seconds (equivalent to one month) and for 14 minutes (equivalent to three months) using a soft fleece toothbrush with a mass of 150 gr. The roughness was measured using a surface roughness tester, and the results were tested with repeated ANOVA test and one-way ANOVA. The value of the surface roughness of tooth enamel was significantly different (penamel.

OW CCMP Ocean Surface Wind

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Cross-Calibrated Multi-Platform (CCMP) Ocean Surface Wind Vector Analyses (Atlas et al., 2011) provide a consistent, gap-free long-term time-series of monthly...

Nanoparticle motion on the surface of drying droplets

Science.gov (United States)

Zhao, Mingfei; Yong, Xin

2018-03-01

Advances in solution-based printing and surface patterning techniques for additive manufacturing demand a clear understanding of particle dynamics in drying colloidal droplets and its relationship with deposit structure. Although the evaporation-driven deposition has been studied thoroughly for the particles dispersed in the bulk of the droplet, few investigations have focused on the particles strongly adsorbed to the droplet surface. We modeled the assembly and deposition of the surface-active particles in a drying sessile droplet with a pinned contact line by the multiphase lattice Boltzmann-Brownian dynamics method. The particle trajectory and its area density profile characterize the assembly dynamics and deposition pattern development during evaporation. While the bulk-dispersed particles continuously move to the contact line, forming the typical "coffee-ring" deposit, the interface-bound particles migrate first toward the apex and then to the contact line as the droplet dries out. To understand this unexpected behavior, we resolve the droplet velocity field both in the bulk and within the interfacial region. The simulation results agree well with the analytical solution for the Stokes flow inside an evaporating droplet. At different stages of evaporation, our study reveals that the competition between the tangential surface flow and the downward motion of the evaporating liquid-vapor interface governs the dynamics of the interface-bound particles. In particular, the interface displacement contributes to the particle motion toward the droplet apex in a short phase, while the outward advective flow prevails at the late stage of drying and carries the particles to the contact line. The final deposit of the surface-adsorbed particles exhibits a density enhancement at the center, in addition to a coffee ring. Despite its small influence on the final deposit in the present study, the distinct dynamics of surface-active particles due to the interfacial confinement

Aging of residual surface resistance of superconducting lead cavities

DEFF Research Database (Denmark)

Danielsen, M.

1972-01-01

Measurements of the residual surface resistance of superconducting lead cavities as a function of time during a period of a month showed an oscillating variation. An explanation of the ageing curves is proposed. ©1972 The American Institute of Physics......Measurements of the residual surface resistance of superconducting lead cavities as a function of time during a period of a month showed an oscillating variation. An explanation of the ageing curves is proposed. ©1972 The American Institute of Physics...

Clinical Effectiveness of Using Aesthetic Fixed Prosthetic Appliances with Combined Occlusal Surface

OpenAIRE

Andrii Biben; Zinovii Ozhohan

2017-01-01

The objective of the research was to evaluate the clinical effectiveness of using aesthetic fixed prosthetic appliances with combined occlusal surface. Materials and methods. The study included 30 patients who were divided into 2 groups: Group I included 20 patients with combined occlusal surface of the crowns; Group II included 22 patients with ceramic occlusal surface of the crowns. The patients were observed 3, 6 and 12 months after prosthetic repair. Results. 6 months after prosthet...

Study of Cs adsorption on Ga(Mg)0.75Al0.25N (0 0 0 1) surface: A first principle calculation

International Nuclear Information System (INIS)

Yang, Mingzhu; Chang, Benkang; Hao, Guanghui; Guo, Jing; Wang, Honggang; Wang, Meishan

2013-01-01

In order to study the activation process of Ga 1−x Al x N photocathodes theoretically, models of Cs adsorption on Ga(Mg) 0.75 Al 0.25 N (0 0 0 1) surface are built, then the atomic structure, electronic structure, adsorption energy, work function, dipole moment and optical properties of the models are calculated. All calculations are carried out using Cambridge Serial Total Energy Package (CASTEP) based on first principle. Results show that Cs adsorption on Mg doping Ga 1−x Al x N (0 0 0 1) surface can reduce work function of the surface, and the favorite adsorption site is on the top of p-type impurity. Cs adsorption on p-type Ga 1−x Al x N (0 0 0 1) surface can produce the structure of p-type bulk with n-type surface, which is helpful to surface band bend downward and decrease electron affinity seriously. The absorption coefficient of Cs adsorption system is less than that of the clean surface. Theoretical study of Cs adsorption on Ga 1−x Al x N (0 0 0 1) surface can help to improve activation technology of Ga 1−x Al x N photocathodes.

Comparison between the land surface response of the ECMWF model and the FIFE-1987 data

Science.gov (United States)

Betts, Alan K.; Ball, John H.; Beljaars, Anton C. M.

1993-01-01

An averaged time series for the surface data for the 15 x 15 km FIFE site was prepared for the summer of 1987. Comparisons with 48-hr forecasts from the ECMWF model for extended periods in July, August, and October 1987 identified model errors in the incoming SW radiation in clear skies, the ground heat flux, the formulation of surface evaporation, the soil-moisture model, and the entrainment at boundary-layer top. The model clear-sky SW flux is too high at the surface by 5-10 percent. The ground heat flux is too large by a factor of 2 to 3 because of the large thermal capacity of the first soil layer (which is 7 cm thick), and a time truncation error. The surface evaporation was near zero in October 1987, rather than of order 70 W/sq m at noon. The surface evaporation falls too rapidly after rainfall, with a time-scale of a few days rather than the 7-10 d (or more) of the observations. On time-scales of more than a few days the specified 'climate layer' soil moisture, rather than the storage of precipitation, has a large control on the evapotranspiration. The boundary-layer-top entrainment is too low. This results in a moist bias in the boundary-layer mixing ratio of order 2 g/Kg in forecasts from an experimental analysis with nearly realistic surface fluxes; this because there is insufficient downward mixing of dry air.

Self-consistent electrostatic simulations of reforming double layers in the downward current region of the aurora

Directory of Open Access Journals (Sweden)

H. Gunell

2015-10-01

Full Text Available The plasma on a magnetic field line in the downward current region of the aurora is simulated using a Vlasov model. It is found that an electric field parallel to the magnetic fields is supported by a double layer moving toward higher altitude. The double layer accelerates electrons upward, and these electrons give rise to plasma waves and electron phase-space holes through beam–plasma interaction. The double layer is disrupted when reaching altitudes of 1–2 Earth radii where the Langmuir condition no longer can be satisfied due to the diminishing density of electrons coming up from the ionosphere. During the disruption the potential drop is in part carried by the electron holes. The disruption creates favourable conditions for double layer formation near the ionosphere and double layers form anew in that region. The process repeats itself with a period of approximately 1 min. This period is determined by how far the double layer can reach before being disrupted: a higher disruption altitude corresponds to a longer repetition period. The disruption altitude is, in turn, found to increase with ionospheric density and to decrease with total voltage. The current displays oscillations around a mean value. The period of the oscillations is the same as the recurrence period of the double layer formations. The oscillation amplitude increases with increasing voltage, whereas the mean value of the current is independent of voltage in the 100 to 800 V range covered by our simulations. Instead, the mean value of the current is determined by the electron density at the ionospheric boundary.

MONTHLY AVERAGE FLOW IN RÂUL NEGRU HYDROGRAPHIC BASIN

Directory of Open Access Journals (Sweden)

VIGH MELINDA

2014-03-01

Full Text Available Râul Negru hydrographic basin represents a well individualised and relatively homogenous physical-geographical unity from Braşov Depression. The flow is controlled by six hydrometric stations placed on the main collector and on two of the most powerful tributaries. Our analysis period is represented by the last 25 years (1988 - 2012 and it’s acceptable for make pertinent conclusions. The maximum discharge month is April, that it’s placed in the high flow period: March – June. Minimum discharges appear in November - because of the lack of pluvial precipitations; in January because of high solid precipitations and because of water volume retention in ice. Extreme discharge frequencies vary according to their position: in the mountain area – small basin surface; into a depression – high basin surface. Variation coefficients point out very similar variation principles, showing a relative homogeneity of flow processes.

Surface conductivity of Mercury provides current closure and may affect magnetospheric symmetry

Directory of Open Access Journals (Sweden)

P. Janhunen

2004-04-01

Full Text Available We study what effect a possible surface conductivity of Mercury has on the closure of magnetospheric currents by making six runs with a quasi-neutral hybrid simulation. The runs are otherwise identical but use different synthetic conductivity models: run 1 has a fully conducting planet, run 2 has a poorly conducting planet ( m and runs 3-6 have one of the hemispheres either in the dawn-dusk or day-night directions, conducting well, the other one being conducting poorly. Although the surface conductivity is not known from observations, educated guesses easily give such conductivity values that magnetospheric currents may close partly within the planet, and as the conductivity depends heavily on the mineral composition of the surface, the possibility of significant horizontal variations cannot be easily excluded. The simulation results show that strong horizontal variations may produce modest magnetospheric asymmetries. Beyond the hybrid simulation, we also briefly discuss the possibility that in the nightside there may be a lack of surface electrons to carry downward current, which may act as a further source of surface-related magnetospheric asymmetry.

Key words. Magnetospheric physics (planetary magnetospheres; current systems; solar wind-magnetosphere interactions.6

Validation of the Suomi NPP VIIRS Ice Surface Temperature Environmental Data Record

Directory of Open Access Journals (Sweden)

Yinghui Liu

2015-12-01

Full Text Available Continuous monitoring of the surface temperature is critical to understanding and forecasting Arctic climate change; as surface temperature integrates changes in the surface energy budget. The sea-ice surface temperature (IST has been measured with optical and thermal infrared sensors for many years. With the IST Environmental Data Record (EDR available from the Visible Infrared Imaging Radiometer Suite (VIIRS onboard the Suomi National Polar-orbiting Partnership (NPP and future Joint Polar Satellite System (JPSS satellites; we can continue to monitor and investigate Arctic climate change. This work examines the quality of the VIIRS IST EDR. Validation is performed through comparisons with multiple datasets; including NASA IceBridge measurements; air temperature from Arctic drifting ice buoys; Moderate Resolution Imaging Spectroradiometer (MODIS IST; MODIS IST simultaneous nadir overpass (SNO; and surface air temperature from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR reanalysis. Results show biases of −0.34; −0.12; 0.16; −3.20; and −3.41 K compared to an aircraft-mounted downward-looking pyrometer; MODIS; MODIS SNO; drifting buoy; and NCEP/NCAR reanalysis; respectively; root-mean-square errors of 0.98; 1.02; 0.95; 4.89; and 6.94 K; and root-mean-square errors with the bias removed of 0.92; 1.01; 0.94; 3.70; and 6.04 K. Based on the IceBridge and MODIS results; the VIIRS IST uncertainty (RMSE meets or exceeds the JPSS system requirement of 1.0 K. The product can therefore be considered useful for meteorological and climatological applications.

Wind-sea surface temperature-sea ice relationship in the Chukchi-Beaufort Seas during autumn

Science.gov (United States)

Zhang, Jing; Stegall, Steve T.; Zhang, Xiangdong

2018-03-01

Dramatic climate changes, especially the largest sea ice retreat during September and October, in the Chukchi-Beaufort Seas could be a consequence of, and further enhance, complex air-ice-sea interactions. To detect these interaction signals, statistical relationships between surface wind speed, sea surface temperature (SST), and sea ice concentration (SIC) were analyzed. The results show a negative correlation between wind speed and SIC. The relationships between wind speed and SST are complicated by the presence of sea ice, with a negative correlation over open water but a positive correlation in sea ice dominated areas. The examination of spatial structures indicates that wind speed tends to increase when approaching the ice edge from open water and the area fully covered by sea ice. The anomalous downward radiation and thermal advection, as well as their regional distribution, play important roles in shaping these relationships, though wind-driven sub-grid scale boundary layer processes may also have contributions. Considering the feedback loop involved in the wind-SST-SIC relationships, climate model experiments would be required to further untangle the underlying complex physical processes.

A new approach for monthly updates of anthropogenic sulfur dioxide emissions from space: Application to China and implications for air quality forecasts

Science.gov (United States)

Wang, Yi; Wang, Jun; Xu, Xiaoguang; Henze, Daven K.; Wang, Yuxuan; Qu, Zhen

2016-09-01

SO2 emissions, the largest source of anthropogenic aerosols, can respond rapidly to economic and policy driven changes. However, bottom-up SO2 inventories have inherent limitations owing to 24-48 months latency and lack of month-to-month variation in emissions (especially in developing countries). This study develops a new approach that integrates Ozone Monitoring Instrument (OMI) SO2 satellite measurements and GEOS-Chem adjoint model simulations to constrain monthly anthropogenic SO2 emissions. The approach's effectiveness is demonstrated for 14 months in East Asia; resultant posterior emissions not only capture a 20% SO2 emission reduction in Beijing during the 2008 Olympic Games but also improve agreement between modeled and in situ surface measurements. Further analysis reveals that posterior emissions estimates, compared to the prior, lead to significant improvements in forecasting monthly surface and columnar SO2. With the pending availability of geostationary measurements of tropospheric composition, we show that it may soon be possible to rapidly constrain SO2 emissions and associated air quality predictions at fine spatiotemporal scales.

Theoretical study for heterojunction surface of NEA GaN photocathode dispensed with Cs activation

Science.gov (United States)

Xia, Sihao; Liu, Lei; Wang, Honggang; Wang, Meishan; Kong, Yike

2016-09-01

For the disadvantages of conventional negative electron affinity (NEA) GaN photocathodes activated by Cs or Cs/O, new-type NEA GaN photocathodes with heterojunction surface dispensed with Cs activation are investigated based on first-principle study with density functional theory. Through the growth of an ultrathin n-type GaN cap layer on p-type GaN emission layer, a p-n heterojunction is formed on the surface. According to the calculation results, it is found that Si atoms tend to replace Ga atoms to result in an n-type doped cap layer which contributes to the decreasing of work function. After the growth of n-type GaN cap layer, the atom structure near the p-type emission layer is changed while that away from the surface has no obvious variations. By analyzing the E-Mulliken charge distribution of emission surface with and without cap layer, it is found that the positive charge of Ga and Mg atoms in the emission layer decrease caused by the cap layer, while the negative charge of N atom increases. The conduction band moves downwards after the growth of cap layer. Si atom produces donor levels around the valence band maximum. The absorption coefficient of GaN emission layer decreases and the reflectivity increases caused by n-type GaN cap layer.

Global monthly water scarcity: blue water footprints versus blue water availability.

Science.gov (United States)

Hoekstra, Arjen Y; Mekonnen, Mesfin M; Chapagain, Ashok K; Mathews, Ruth E; Richter, Brian D

2012-01-01

Freshwater scarcity is a growing concern, placing considerable importance on the accuracy of indicators used to characterize and map water scarcity worldwide. We improve upon past efforts by using estimates of blue water footprints (consumptive use of ground- and surface water flows) rather than water withdrawals, accounting for the flows needed to sustain critical ecological functions and by considering monthly rather than annual values. We analyzed 405 river basins for the period 1996-2005. In 201 basins with 2.67 billion inhabitants there was severe water scarcity during at least one month of the year. The ecological and economic consequences of increasing degrees of water scarcity--as evidenced by the Rio Grande (Rio Bravo), Indus, and Murray-Darling River Basins--can include complete desiccation during dry seasons, decimation of aquatic biodiversity, and substantial economic disruption.

Experimental investigation of the effects of orientation angle on heat transfer performance of pin-finned surfaces in natural convection

International Nuclear Information System (INIS)

Sertkaya, Ahmet Ali; Bilir, Sefik; Kargici, Suna

2011-01-01

Natural convection heat transfer in air from a pin-finned surface is investigated experimentally by considering the effect of radiation heat transfer. The plate was oriented as the pin arrays facing either downwards or upwards from vertical axis with different angles and the experiments were performed for different values of heater power input. From the results of the experiments it is observed that the pin fins increase the heat transfer considerably when compared to the unpinned surface. The upfacing pins are more enhancing heat transfer than the downfacing pins and the enhancement is decreasing with increasing orientation angle from the vertical axis. -- Research highlights: → Effect of orientation in free convection heat transfer from a pin-finned surface. → The upfacing pins are more enhancing heat transfer than the downfacing pins. → Radiation view factor is calculated by a modular analysis. → The radiation is comparable to free convection as not to be neglected. → The radiative part is 25-40% and increases for low heat transfer rates.

Helioseismic measurements in the solar envelope using group velocities of surface waves

Science.gov (United States)

Vorontsov, S. V.; Baturin, V. A.; Ayukov, S. V.; Gryaznov, V. K.

2014-07-01

At intermediate- and high-degree l, solar p and f modes can be considered as surface waves. Using variational principle, we derive an integral expression for the group velocities of the surface waves in terms of adiabatic eigenfunctions of normal modes, and address the benefits of using group-velocity measurements as a supplementary diagnostic tool in solar seismology. The principal advantage of using group velocities, when compared with direct analysis of the oscillation frequencies, comes from their smaller sensitivity to the uncertainties in the near-photospheric layers. We address some numerical examples where group velocities are used to reveal inconsistencies between the solar models and the seismic data. Further, we implement the group-velocity measurements to the calibration of the specific entropy, helium abundance Y, and heavy-element abundance Z in the adiabatically stratified part of the solar convective envelope, using different recent versions of the equation of state. The results are in close agreement with our earlier measurements based on more sophisticated analysis of the solar oscillation frequencies. These results bring further support to the downward revision of the solar heavy-element abundances in recent spectroscopic measurements.

Downward carbon transport in a 2000-year rice paddy soil chronosequence traced by radiocarbon measurements

Energy Technology Data Exchange (ETDEWEB)

Braeuer, T., E-mail: tbraeuer@leibniz.uni-kiel.de [Leibniz-Laboratory, Christian-Albrechts-University, Kiel (Germany); Grootes, P.M.; Nadeau, M.-J.; Andersen, N. [Leibniz-Laboratory, Christian-Albrechts-University, Kiel (Germany)

2013-01-15

Paddy and non-paddy soils from a chronosequence of 50-2000 years of agricultural use, developed on former estuarine sediments of the Yangtze River, were sampled near Cixi, Zhejiang Province, China, in the framework of the Research Unit 'Biogeochemistry of paddy soil evolution' of the German Research Foundation (DFG). In addition samples of Yangtze River estuarine sediments were obtained. The parent sediment shows a fairly homogeneous composition with ca. 0.3% TOC and a {sup 14}C concentration of ca. 50 pMC. After being diked-in, gradients in soil organic carbon and {sup 14}C concentration develop under the influence of vegetation and cultivation. In the non-paddy soil, a {sup 14}C gradient with concentration decreasing with increasing depth from modern (>100 pMC) to original sediment values around 50 pMC is already established after 50 years and can also be observed in the older sites. In contrast, the 50 years old paddy soil shows organic carbon and {sup 14}C enrichment only in the A-horizon and a nearly constant TOC and {sup 14}C stock of original sediment below the plough pan. To test the basic approach that the soil profile development started on homogeneous sediment, an isotope and mass balance calculation was used. The results show a quite similar age composition of different sample sites. Paddy rice cultivation quickly leads to a dense plough pan, which seriously reduces, but not totally prevents, downward transport of organic matter. The equilibrium times for TOC and {sup 14}C in paddy soil profiles are short (decades) in the topsoil and in the order of centuries in the subsoil, underlining the dynamic character of soil organic carbon.

NDE of Damage in Aircraft Flight Control Surfaces

International Nuclear Information System (INIS)

Hsu, David K.; Barnard, Daniel J.; Dayal, Vinay

2007-01-01

Flight control surfaces on an aircraft, such as ailerons, flaps, spoilers and rudders, are typically adhesively bonded composite or aluminum honeycomb sandwich structures. These components can suffer from damage caused by hail stone, runway debris, or dropped tools during maintenance. On composites, low velocity impact damages can escape visual inspection, whereas on aluminum honeycomb sandwich, budding failure of the honeycomb core may or may not be accompanied by a disbond. This paper reports a study of the damage morphology in such structures and the NDE methods for detecting and characterizing them. Impact damages or overload failures in composite sandwiches with Nomex or fiberglass core tend to be a fracture or crinkle or the honeycomb cell wall located a distance below the facesheet-to-core bondline. The damage in aluminum honeycomb is usually a buckling failure, propagating from the top skin downward. The NDE methods used in this work for mapping out these damages were: air-coupled ultrasonic scan, and imaging by computer aided tap tester. Representative results obtained from the field will be shown

Data Descriptor: TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958-2015

Science.gov (United States)

John T. Abatzoglou; Solomon Z. Dobrowski; Sean A. Parks; Katherine C. Hegewisch

2018-01-01

We present TerraClimate, a dataset of high-spatial resolution (1/24°, ~4-km) monthly climate and climatic water balance for global terrestrial surfaces from 1958–2015. TerraClimate uses climatically aided interpolation, combining high-spatial resolution climatological normals from the WorldClim dataset, with coarser resolution time varying (i.e., monthly) data from...

Surface chemistry and electronic structure of nonpolar and polar GaN films

Energy Technology Data Exchange (ETDEWEB)

Mishra, Monu; Krishna, T.C. Shibin; Aggarwal, Neha; Gupta, Govind, E-mail: govind@nplindia.org

2015-08-01

Highlights: • Surface chemistry and electronic structure of polar and nonpolar GaN is reported. • Influence of polarization on electron affinity of p & np GaN films is investigated. • Correlation between surface morphology and polarity has been deduced. - Abstract: Photoemission and microscopic analysis of nonpolar (a-GaN/r-Sapphire) and polar (c-GaN/c-Sapphire) epitaxial gallium nitride (GaN) films grown via RF-Molecular Beam Epitaxy is reported. The effect of polarization on surface properties like surface states, electronic structure, chemical bonding and morphology has been investigated and correlated. It was observed that polarization lead to shifts in core level (CL) as well as valence band (VB) spectra. Angle dependent X-ray Photoelectron Spectroscopic analysis revealed higher surface oxide in polar GaN film compared to nonpolar GaN film. On varying the take off angle (TOA) from 0° to 60°, the Ga−O/Ga−N ratio varied from 0.11–0.23 for nonpolar and 0.17–0.36 for polar GaN film. The nonpolar film exhibited N-face polarity while Ga-face polarity was perceived in polar GaN film due to the inherent polarization effect. Polarization charge compensated surface states were observed on the polar GaN film and resulted in downward band bending. Ultraviolet photoelectron spectroscopic measurements revealed electron affinity and ionization energy of 3.4 ± 0.1 eV and 6.8 ± 0.1 eV for nonpolar GaN film and 3.8 ± 0.1 eV and 7.2 ± 0.1 eV for polar GaN film respectively. Field Emission Scanning Electron Microscopy measurements divulged smooth morphology with pits on polar GaN film. The nonpolar film on the other hand showed pyramidal structures having facets all over the surface.

Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains Central Facility

Energy Technology Data Exchange (ETDEWEB)

McFarlane, Sally A.; Gaustad, Krista L.; Mlawer, Eli J.; Long, Charles N.; Delamere, Jennifer

2011-09-01

We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

Science.gov (United States)

McFarlane, S. A.; Gaustad, K. L.; Mlawer, E. J.; Long, C. N.; Delamere, J.

2011-09-01

We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility

Directory of Open Access Journals (Sweden)

J. Delamere

2011-09-01

Full Text Available We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM facility at the Southern Great Plains (SGP site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs, four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated can be identified. A normalized difference vegetation index (NDVI is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.

Efficacy of two-month treatment with Xiloial eyedrops for discomfort from disposable soft contact lenses.

Science.gov (United States)

Versura, Piera; Profazio, Vincenzo; Balducci, Nicole; Campos, Emilio C

2010-09-20

To evaluate the efficacy and tolerability of Xiloial(®) monodose eyedrops in the treatment of patients suffering from subjective symptoms of discomfort related to disposable soft contact lens (dSCL) wear. Fifteen (12 female, three male, medium age 39 ± 9 years) dSCL wearers were enrolled. Inclusion criteria were Ocular Surface Disease Index (ODSI) symptom questionnaire score >12, tear film break-up time (TFBUT) 10 mm over five minutes, mild punctuate keratopathy, and conjunctival staining (Oxford grading ≤4). Monodose Xiloial eyedrops were administered three times daily for a two-month period. Patients were evaluated at enrollment, after three days of washout (baseline), and after one and two months of treatment, by OSDI score, Schirmer test I, TFBUT, ferning test, ocular surface damage (Oxford grade), and serum albumin in tears (index of passive exudation related to serum leakage). At endpoint versus baseline, respectively, the mean ± standard deviation of all variables improved as follows: OSDI (8.5 ± 3 versus 20.2 ± 1.6); TFBUT (9.6 ± 1.1 versus 7.1 ± 1.0); Oxford grading (0.5 ± 0.1 versus 3.6 ± 0.8); ferning test (2 ± 1 versus 2.4 ± 0.5); and Schirmer test I (14.6 ± 1.1 versus 12 ± 2.1), with P < 0.05 for all variables (Friedman and Wilcoxon tests). Tolerability was high, with no adverse events noted. A two-month treatment with Xiloial showed good tolerance and appeared to reduce ocular surface damage and symptoms of discomfort.

Sequential Subterranean Transport of Excavated Sand and Foraged Seeds in Nests of the Harvester Ant, Pogonomyrmex badius.

Directory of Open Access Journals (Sweden)

Walter R Tschinkel

Full Text Available During their approximately annual nest relocations, Florida harvester ants (Pogonomyrmex badius excavate large and architecturally-distinct subterranean nests. Aspects of this process were studied by planting a harvester ant colony in the field in a soil column composed of layers of 12 different colors of sand. Quantifying the colors of excavated sand dumped on the surface by the ants revealed the progress of nest deepening to 2 m and enlargement to 8 L in volume. Most of the excavation was completed within about 2 weeks, but the nest was doubled in volume after a winter lull. After 7 months, we excavated the nest and mapped its structure, revealing colored sand deposited in non-host colored layers, especially in the upper 30 to 40 cm of the nest. In all, about 2.5% of the excavated sediment was deposited below ground, a fact of importance to sediment dating by optically-stimulated luminescence (OSL. Upward transport of excavated sand is carried out in stages, probably by different groups of ants, through deposition, re-transport, incorporation into the nest walls and floors and remobilization from these. This results in considerable mixing of sand from different depths, as indicated in the multiple sand colors even within single sand pellets brought to the surface. Just as sand is transported upward by stages, incoming seeds are transported downward to seed chambers. Foragers collect seeds and deposit them only in the topmost nest chambers from which a separate group of workers rapidly transports them downward in increments detectable as a "wave" of seeds that eventually ends in the seed chambers, 20 to 80 cm below the surface. The upward and downward transport is an example of task-partitioning in a series-parallel organization of work carried out by a highly redundant work force in which each worker usually completes only part of a multi-step process.

Water entry without surface seal: Extended cavity formation

KAUST Repository

Mansoor, Mohammad M.; Marston, Jeremy; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur T

2014-01-01

for values of Hp/H as the observed undulations are induced above the first pinch-off point as the impact speed increases. We also report observations of 'kinked' pinch-off points and the suppression of downward facing jets in the presence of wall effects

The boundary condition for vertical velocity and its interdependence with surface gas exchange

Science.gov (United States)

Kowalski, Andrew S.

2017-07-01

The law of conservation of linear momentum is applied to surface gas exchanges, employing scale analysis to diagnose the vertical velocity (w) in the boundary layer. Net upward momentum in the surface layer is forced by evaporation (E) and defines non-zero vertical motion, with a magnitude defined by the ratio of E to the air density, as w = E/ρ. This is true even right down at the surface where the boundary condition is w|0 = E/ρ|0 (where w|0 and ρ|0 represent the vertical velocity and density of air at the surface). This Stefan flow velocity implies upward transport of a non-diffusive nature that is a general feature of the troposphere but is of particular importance at the surface, where it assists molecular diffusion with upward gas migration (of H2O, for example) but opposes that of downward-diffusing species like CO2 during daytime. The definition of flux-gradient relationships (eddy diffusivities) requires rectification to exclude non-diffusive transport, which does not depend on scalar gradients. At the microscopic scale, the role of non-diffusive transport in the process of evaporation from inside a narrow tube - with vapour transport into an overlying, horizontal airstream - was described long ago in classical mechanics and is routinely accounted for by chemical engineers, but has been neglected by scientists studying stomatal conductance. Correctly accounting for non-diffusive transport through stomata, which can appreciably reduce net CO2 transport and marginally boost that of water vapour, should improve characterisations of ecosystem and plant functioning.

Assessment of BSRN radiation records for the computation of monthly means

Science.gov (United States)

Roesch, A.; Wild, M.; Ohmura, A.; Dutton, E. G.; Long, C. N.; Zhang, T.

2011-02-01

The integrity of the Baseline Surface Radiation Network (BSRN) radiation monthly averages are assessed by investigating the impact on monthly means due to the frequency of data gaps caused by missing or discarded high time resolution data. The monthly statistics, especially means, are considered to be important and useful values for climate research, model performance evaluations and for assessing the quality of satellite (time- and space-averaged) data products. The study investigates the spread in different algorithms that have been applied for the computation of monthly means from 1-min values. The paper reveals that the computation of monthly means from 1-min observations distinctly depends on the method utilized to account for the missing data. The intra-method difference generally increases with an increasing fraction of missing data. We found that a substantial fraction of the radiation fluxes observed at BSRN sites is either missing or flagged as questionable. The percentage of missing data is 4.4%, 13.0%, and 6.5% for global radiation, direct shortwave radiation, and downwelling longwave radiation, respectively. Most flagged data in the shortwave are due to nighttime instrumental noise and can reasonably be set to zero after correcting for thermal offsets in the daytime data. The study demonstrates that the handling of flagged data clearly impacts on monthly mean estimates obtained with different methods. We showed that the spread of monthly shortwave fluxes is generally clearly higher than for downwelling longwave radiation. Overall, BSRN observations provide sufficient accuracy and completeness for reliable estimates of monthly mean values. However, the value of future data could be further increased by reducing the frequency of data gaps and the number of outliers. It is shown that two independent methods for accounting for the diurnal and seasonal variations in the missing data permit consistent monthly means to within less than 1 W m-2 in most cases

Analysis of monthly variability of thermocline in the South China Sea

Science.gov (United States)

Peng, Hanbang; Pan, Aijun; Zheng, Quan'an; Hu, Jianyu

2018-03-01

This study analyzes monthly variability of thermocline and its mechanism in the South China Sea (SCS). The study is based on 51-year (1960-2010) monthly seawater temperature and surface wind stress data from Simple Ocean Data Assimilation (SODA), together with heat flux, precipitation and evaporation data from the National Centers for Environmental Prediction (NCEP), the National Oceanic and Atmospheric Administration (NOAA) and the Woods Hole Oceanographic Institution, respectively. The results reveal that the upper boundary depth ( Z up), lower boundary depth ( Z low), thickness (Δ Z) and intensity ( T z ) of thermocline in the SCS show remarkable monthly variability. Being averaged for the deep basin of SCS, Z up deepens gradually from May to the following January and then shoals from February to May, while Z low varies little throughout the whole year. Further diagnostics indicates that the monthly variability of Z up is mainly caused by the buoyancy flux and wind stress curl. Using a linear method, the impacts of the buoyancy flux and wind stress curl on Z up can be quantitatively distinguished. The results suggest that Z up tends to deepen about 4.6 m when the buoyancy flux increases by 1×10 -5 kg/(m•s 3), while it shoals about 2.5 m when the wind stress curl strengthens by 1×10 -7 N/m³.

The segmentation of sub-lexical morphemes in English-learning 15-month-olds

Directory of Open Access Journals (Sweden)

Toben H. Mintz

2013-02-01

Full Text Available In most human languages, important components of linguistic structure are carried by affixes, also called bound morphemes. The affixes in a language comprise a relatively small but frequently occurring set of forms that surface as parts of words, but never occur without a stem. They combine productively with word stems and other grammatical entities in systematic and predictable ways. For example, the English suffix –ing occurs on verb stems, and in combination with a form of the auxiliary verb be, marks the verb with progressive aspect (e.g., was walking. In acquiring a language, learners must acquire rules of combination for affixes. However, prior to learning these combinatorial rules, learners are faced with discovering what the sub-lexical forms are over which the rules operate. That is, they have to discover the bound morphemes themselves. It is not known when English-learners begin to analyze words into morphological units. Previous research with learners of English found evidence that 18-month-olds have started to learn the combinatorial rules involving bound morphemes, and that 15-month-olds have not. However, it is not known whether 15-month-olds nevertheless represent the morphemes as distinct entities. This present study demonstrates that when 15-month-olds process words that end in ¬–ing, they segment ¬the suffix from the word, but they do not do so with endings that are not morphemes. Eight-month olds do not show this capacity. Thus, 15-month-olds have already started to identify bound morphemes and actively use them in processing speech.

Transition from 12 months to 18 months cycles at Krsko in a core physics perspective

International Nuclear Information System (INIS)

Jensen-Tornehed, J.

2004-01-01

Krsko has historically been operating in 12 months cycles with an annual outage for refuelling and maintenance work. Krsko is now in a transition from 12 months to 18 months cycles. Cycle 19, June 2002 - May 2003, was the last 12 month cycle. Cycle 20, June 2003 - September 2004 is a 15 month transition cycle and cycle 21, September 2004 - April 2006 will be the first 18 month cycle. This paper will describe the effects of the transition in a core physics perspective. There are big differences in how to design an 18 month cycle in comparison with a 12 month cycle. The required number of feed assemblies increases, as well as the content of burnable absorbers in the fuel. The strategy of the loading pattern has to be changed with the increased number of fresh fuel assemblies. The most limiting margins can be different for different cycle lengths which also affect the fresh assembly design and loading pattern during the transition. During the core design for cycle 21 the Moderator Temperature Coefficient was the main issue, which caused the need for extra amount of burnable absorbers. (author)

Impact of CO/sub 2/ on cooling of snow and water surfaces

Energy Technology Data Exchange (ETDEWEB)

Choudhury, B [Computer Sciences Corp., Silver Spring, MD; Kukla, G

1979-08-23

The levels of CO/sub 2/ in the atmosphere are being increased by the burning of fossil fuels and reduction of biomass. It has been calculated that the increase in CO/sub 2/ levels should lead to global warming because of increased absorption by the atmosphere of terrestrial longwave radiation in the far IR (> 5 ..mu..m). From model computations, CO/sub 2/ is expected to produce the largest climatic effect in high latitudes by reducing the size of ice and snow fields. We present here computations of spectral radiative transfer and scattering within a snow pack and water. The results suggest that CO/sub 2/ significantly reduces the shortwave energy absorbed by the surface of snow and water. The energy deficit, when not compensated by downward atmospheric radiation, may delay the recrystallisation of snow and dissipation of packice and result in a cooling rather than a warming effect.

A single LipiFlow® Thermal Pulsation System treatment improves meibomian gland function and reduces dry eye symptoms for 9 months.

Science.gov (United States)

Greiner, Jack V

2012-04-01

To evaluate the effect of a single treatment with the LipiFlow(®) Thermal Pulsation System on signs of meibomian gland dysfunction (MGD) and dry eye symptoms over a 9-month period. Patients (n = 42 eyes, 21 subjects) diagnosed with MGD and dry eye symptoms were recruited for a non-significant risk, prospective, open-label, 1-month clinical trial. Patients received a single 12-minute treatment using the LipiFlow(®) Thermal Pulsation System on each eye. The LipiFlow(®) device applies heat to the conjunctival surfaces of the upper and lower inner eyelids while simultaneously applying pulsatile pressure to the outer eyelid surfaces to express the meibomian glands. Patient symptoms were evaluated using the Ocular Surface Disease Index (OSDI) and Standard Patient Evaluation for Eye Dryness (SPEED) dry eye questionnaires; tear break-up time was measured with the dry eye test (DET™); and meibomian gland function was evaluated using a standardized diagnostic expression technique. Data are presented for patient's pre-treatment (baseline) and at 1-month and 9-month post-treatment. Meibomian gland secretion scores improved significantly from baseline (4.4 ± 4.0) to 1-month post-treatment (11.3 ± 6.2; p dry eye disease, the LipiFlow(®) Thermal Pulsation System offers a technological advancement for the treatment of dry eye disease secondary to meibomian gland dysfunction. A single 12-minute LipiFlow(®) treatment results in up to 9 months of sustained improvement of meibomian gland function, tear break-up time and dry eye symptoms that are unparalleled with current dry eye treatments.

Recent Development on the NOAA's Global Surface Temperature Dataset

Science.gov (United States)

Zhang, H. M.; Huang, B.; Boyer, T.; Lawrimore, J. H.; Menne, M. J.; Rennie, J.

2016-12-01

Global Surface Temperature (GST) is one of the most widely used indicators for climate trend and extreme analyses. A widely used GST dataset is the NOAA merged land-ocean surface temperature dataset known as NOAAGlobalTemp (formerly MLOST). The NOAAGlobalTemp had recently been updated from version 3.5.4 to version 4. The update includes a significant improvement in the ocean surface component (Extended Reconstructed Sea Surface Temperature or ERSST, from version 3b to version 4) which resulted in an increased temperature trends in recent decades. Since then, advancements in both the ocean component (ERSST) and land component (GHCN-Monthly) have been made, including the inclusion of Argo float SSTs and expanded EOT modes in ERSST, and the use of ISTI databank in GHCN-Monthly. In this presentation, we describe the impact of those improvements on the merged global temperature dataset, in terms of global trends and other aspects.

Range of monthly mean hourly land surface air temperature diurnal cycle over high northern latitudes

Science.gov (United States)

Wang, Aihui; Zeng, Xubin

2014-05-01

Daily maximum and minimum temperatures over global land are fundamental climate variables, and their difference represents the diurnal temperature range (DTR). While the differences between the monthly averaged DTR (MDTR) and the range of monthly averaged hourly temperature diurnal cycle (RMDT) are easy to understand qualitatively, their differences have not been quantified over global land areas. Based on our newly developed in situ data (Climatic Research Unit) reanalysis (Modern-Era Retrospective analysis for Research and Applications) merged hourly temperature data from 1979 to 2009, RMDT in January is found to be much smaller than that in July over high northern latitudes, as it is much more affected by the diurnal radiative forcing than by the horizontal advection of temperature. In contrast, MDTR in January is comparable to that in July over high northern latitudes, but it is much larger than January RMDT, as it primarily reflects the movement of lower frequency synoptic weather systems. The area-averaged RMDT trends north of 40°N are near zero in November, December, and January, while the trends of MDTR are negative. These results suggest the need to use both the traditional MDTR and RMDT suggested here in future observational and modeling studies. Furthermore, MDTR and its trend are more sensitive to the starting hour of a 24 h day used in the calculations than those for RMDT, and this factor also needs to be considered in model evaluations using observational data.

The effect of step thickness on the surface diffusion of a Pt adatom

International Nuclear Information System (INIS)

Yang, Jianyu; Deng, Yonghe; Xiao, Gang; Hu, Wangyu; Chen, Shuguang

2009-01-01

The diffusion of a single Pt adatom on the Pt(1 1 1) surface with {1 1 1}-faceted steps is studied using a combination of molecular dynamics and the nudged elastic band method. The interatomic interactions are described with the analytic embedded atom method. The simulation indicates that before diffusion across the descending step, the adatom becomes trapped at the step edge, and has to overcome an energy barrier to return the plane's center. The energy barrier for adatom migration to the step edge is almost independent of step thickness. In addition, the step thickness dependence of the diffusion energy barrier for the adatom over descending and ascending steps edge is obtained. For a monolayer step, the upward diffusion of the adatom to the {1 1 1}-faceted steps is very rare as compared with the downward diffusion. However, the probability of the adatom to ascend the {1 1 1}-faceted steps increases with increasing step thickness. The calculated character temperatures indicate the three-dimensional pyramidal island on the clean Pt(1 1 1) surface can be formed at higher temperature

The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present)

Science.gov (United States)

Adler, Robert F.; Huffman, George J.; Chang, Alfred; Ferraro, Ralph; Xie, Ping-Ping; Janowiak, John; Rudolf, Bruno; Schneider, Udo; Curtis, Scott; Bolvin, David

2003-01-01

The Global Precipitation Climatology Project (GPCP) Version 2 Monthly Precipitation Analysis is described. This globally complete, monthly analysis of surface precipitation at 2.5 degrees x 2.5 degrees latitude-longitude resolution is available from January 1979 to the present. It is a merged analysis that incorporates precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The merging approach utilizes the higher accuracy of the low-orbit microwave observations to calibrate, or adjust, the more frequent geosynchronous infrared observations. The data set is extended back into the premicrowave era (before 1987) by using infrared-only observations calibrated to the microwave-based analysis of the later years. The combined satellite-based product is adjusted by the raingauge analysis. This monthly analysis is the foundation for the GPCP suite of products including those at finer temporal resolution, satellite estimate, and error estimates for each field. The 23-year GPCP climatology is characterized, along with time and space variations of precipitation.

Surface layer and bloom dynamics observed with the Prince William Sound Autonomous Profiler

Science.gov (United States)

Campbell, R. W.

2016-02-01

As part of a recent long term monitoring effort, deployments of a WETLabs Autonomous Moored Profiler (AMP) began Prince William Sound (PWS) in 2013. The PWS AMP consists of a positively buoyant instrument frame, with a winch and associated electronics that profiles the frame from a park depth (usually 55 m) to the surface by releasing and retrieving a thin UHMWPE tether; it generally conducts a daily cast and measures temperature, salinity, chlorophyll-a fluorescence, turbidity, and oxygen and nitrate concentrations. Upward and downward looking ADCPs are mounted on a float below the profiler, and an in situ plankton imager is in development and will be installed in 2016. Autonomous profilers are a relatively new technology, and early deployments experienced a number of failures from which valuable lessons may be learned. Nevertheless, an unprecedented time series of the seasonal biogeochemical procession in the surface waters coastal Gulf of Alaska was collected in 2014 and 2015. The northern Gulf of Alaska has experienced a widespread warm anomaly since early 2014, and surface layer temperature anomalies in PWS were strongly positive during winter 2014. The spring bloom observed by the profiler began 2-3 weeks earlier than average, with surface nitrate depleted by late April. Although surface temperatures were still above average in 2015, bloom timing was much later, with a short vigorous bloom in late April and a subsurface bloom in late May that coincided with significant nitrate drawdown. As well as the vernal blooms, wind-driven upwelling events lead to several small productivity pulses that were evident in changes in nitrate and oxygen concentrations, and chlorophyll-a fluorescence. As well as providing a mechanistic understanding of surface layer biogeochemistry, high frequency observations such as these put historical observations in context, and provide new insights into the scales of variability in the annual cycles of the surface ocean in the North

Regional parametrisation of a monthly hydrological model for estimating discharges in ungaued catchments

Science.gov (United States)

Hlavcova, K.; Szolgay, J.; Kohnova, S.; Kalas, M.

2003-04-01

In the case of the absence of measured runoff optimisation techniques cannot be used to estimate the parameters of monthly rainfall-runoff models. In such a case usually empirical regression methods were used for relating the model parameters to the catchment characteristics in a given region. In the paper a different method for the regional calibration of a monthly water balance model, which can be used for planning purposes, is proposed. Instead of using the regional regression approach a method is proposed, which involves the calibration of a monthly water balance model to gauged sites in the given region simultaneously. A regional objective function was constructed and for the calibration a genetic programming algorithm was employed. It is expected, that the regionally calibrated model parameters can be used in ungauged basins with similar physiographic conditions. The comparison of the performance of such a regional calibration scheme was compared with two single site calibration methods in a region of West Slovakia. The results are based on a study that aimed at computing surface water inflow into a lowland area with valuable groundwater resources. Monthly discharge time series had to be estimated in small ungauged rivers entering the study area.

Correlations Between Sea-Surface Salinity Tendencies and Freshwater Fluxes in the Pacific Ocean

Science.gov (United States)

Li, Zhen; Adamec, David

2007-01-01

Temporal changes in sea-surface salinity (SSS) from 21 years of a high resolution model integration of the Pacific Ocean are correlated with the freshwater flux that was used to force the integration. The correlations are calculated on a 1 x10 grid, and on a monthly scale to assess the possibility of deducing evaporation minus precipitation (E-P) fields from the salinity measurements to be taken by the upcoming Aquarius/SAC-D mission. Correlations between the monthly mean E-P fields and monthly mean SSS temporal tendencies are mainly zonally-oriented, and are highest where the local precipitation is relatively high. Nonseasonal (deviations from the monthly mean) correlations are highest along mid-latitude storm tracks and are relatively small in the tropics. The response of the model's surface salinity to surface forcing is very complex, and retrievals of freshwater fluxes from SSS measurements alone will require consideration of other processes, including horizontal advection and vertical mixing, rather than a simple balance between the two.

Moderate Acute Malnutrition Treatment among Children 6-23 Months and 24-59 Months Aged

International Nuclear Information System (INIS)

Mahamadou, Tanimoune; Traore, Modibo; Fainke, Kamayera; Magagi, Saidou

2014-01-01

Full text: The prevalence of acute malnutrition in Mali has slightly decreased between 2012 and 2013 in southern areas from 8.9 to 8.6 percent.The youngest children 6-23 months are seriously affected as 12.6% according the SMART nutrition survey in 2013. The aim of this study was to show how seasonality impacts relapse rates among youngest moderately malnourished children aged 6-23 month compare to 24-59 months. The World Food Programme in Mali set up Targeted Supplementary Feeding Programme (TSFP) in 1032 community health facilities to address the burden of MAM. This TSFP includes treatment of MAM with 92g of Plumpy’SupTM per days during 60 days. The entry criteria according to national protocol was Mid Upper Arm Circumference less than 125mm (MUAC = 125 mm or WHZ > = -1.5 during two consecutives visits. In addition, the programme is accompanied with community based activities such as active screening and culinary demonstration for women groups and sensitization. As a result, after 10 months of implementation, 41604 children 6-23 months aged have been admitted for MAM treatment. This represents 82% of total estimated caseload in this group (50666). During the same period, only 14% (14473) of total estimated caseload (101333) in children 24-59 months aged group have been admitted and treated. Although 74% (41604) of total admission (56077 children 6-59 months) was 6-23 months aged ,the programme performance indicators show that children 24-59 respond better to the treatment compared to 6-23 months: Average recovery rate 88% vs 87%; death rate 0.55% vs 1.07% none response 0.21% vs 0.50%. Only, the defaulter rate was higher in 24-59, 10.21% vs 7.5%. Nevertheless, compared two Sphere performance norms and threshold, the programme is fully satisfactory in all categories. The seasonal analysis shows that the highest admission in MAM programme was registered between April and September in all categories. 79% of the total caseload has been admitted during this period

Natural gas monthly, August 1995

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-08-24

The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. This month`s feature article is on US Natural Gas Imports and Exports 1994.

Nuclear boiling heat transfer and critical heat flux in titanium dioxide-water nanofluids

International Nuclear Information System (INIS)

Okawa, Tomio; Takamura, Masahiro; Kamiya, Takahito

2011-01-01

Nucleate boiling heat transfer was experimentally studied for saturated pool boiling of water-based nanofluids. Since significant nanoparticle deposition on the heated surface was observed after the nucleate boiling in nanofluids, measurement of CHF was also carried out using the nanoparticle deposited heated surface; pure water was used in the CHF measurement. In the present work, the heated surface was a 20 mm diameter cupper surface, and titanium-dioxide was selected as the material of nanoparticles. Experiments were performed for upward- and downward-facing surfaces. Although the CHFs for the downward-facing surface were generally lower than those for the upward-facing surface, the CHFs for the nanoparticle deposited surface were about 1.9 times greater than those for the bare surface in both the configurations. The CHF improvement corresponded well to the reduction of the surface contact angle. During the nucleate boiling in nanofluids, the boiling heat transfer showed peculiar behavior; it was first deteriorated, then improved, and finally approached to an equilibrium state. This observation indicated that the present nanofluid had competing effects to deteriorate and improve the nucleate boiling heat transfer. It was assumed that the wettability and the roughness of the heated surface were influenced by the deposited nanoparticles to cause complex variation of the number of active nucleation sites. During the nucleate boiling of pure water using the downward-facing surface, a sudden increase in the wall temperature was observed stochastically probably due to the accumulation of bubbles beneath the heated surface. Such behavior was not observed when the pure water was replaced by the nanofluid. (author)

Ultimate Cavity Dynamics of Hydrophobic Spheres Impacting on Free Water Surfaces

KAUST Repository

Mansoor, Mohammad M.

2012-12-01

Cavity formation resulting from the water-entry of solid objects has been the subject of extensive research owing to its practical relevance in naval, military, industrial, sports and biological applications. The cavity formed by an impacting hydrophobic sphere normally seals at two places, one below (deep seal) and the other above the water surface (surface seal). For Froude numbers , the air flow into the resulting cavity is strong enough to suck the splash crown above the surface and disrupt the cavity dynamics before it deep seals. In this research work we eliminate surface seals by means of a novel practice of using cone splash-guards and examine the undisturbed transient cavity dynamics by impact of hydrophobic spheres for Froude numbers ranging . This enabled the measurement of extremely accurate pinch-off heights, pinch-off times, radial cavity collapse rates, and jet speeds in an extended range of Froude numbers compared to the previous work of Duclaux et al. (2007). Results in the extended regime were in remarkable agreement with the theoretical prediction of scaled pinch-off depth, and experimentally derived pinch-off time for . Furthermore, we investigated the influence of confinement on cavity formation by varying the cross-sectional area of the tank of liquid. In conjunction with surface seal elimination we observed the formation of multiple pinch-off points where a maximum of four deep seals were obtained in a sequential order for the Froude number range investigated. The presence of an elongated cavity beneath the first pinch-off point 5 resulted in evident "kinks" primarily related to the greatly diminished air pressure at the necking region caused by supersonic air flows (Gekle et al. 2010). Such flows passing through second pinch-offs were also found to choke the cavities beneath the first pinch- off depths causing radial expansion and hence disappearance of downward jets.

Reactor cavity seal ring

International Nuclear Information System (INIS)

Hankinson, M.F.

1986-01-01

A hydrostatic seal is described for sealing an annular gap between two flat substantially horizontal coplanar surfaces comprising, in combination: a generally flat annular plate of a width sufficient to span a gap between two surfaces: compressible annular sealing means disposed on the bottom surface of the flat annular plate for sealingly engaging the two flat surfaces in response to a downward force exerted on the plate; and fastening means, distributed along the center line of the plate, for releasably fastening the plate in a position to span the gap to be sealed and exert a downward force on the plate, each fastening means including a pair of elongated members of a size to fit into the gap to be sealed, means for mounting the members on the bottom surface of the plate so that at least a portion of each member is radially moveable in a direction toward a respective one of the vertical side surfaces defining the gap to be sealed to engage same and so that the plate is moveable relative to the members in a downward direction in response to hydrostatic pressure applied to the upper surface of the plate when the members are engaging the vertical side surfaces of an annular gap, and an actuating means, mounted on the plate for movement therewith in response to hydrostatic pressure, for radially moving the members, the actuating means extending through a bore in the plate to the upper surface of the plate

Automated detection and association of surface waves

Directory of Open Access Journals (Sweden)

C. R. D. Woodgold

1994-06-01

Full Text Available An algorithm for the automatic detection and association of surface waves has been developed and tested over an 18 month interval on broad band data from the Yellowknife array (YKA. The detection algorithm uses a conventional STA/LTA scheme on data that have been narrow band filtered at 20 s periods and a test is then applied to identify dispersion. An average of 9 surface waves are detected daily using this technique. Beamforming is applied to determine the arrival azimuth; at a nonarray station this could be provided by poIarization analysis. The detected surface waves are associated daily with the events located by the short period array at Yellowknife, and later with the events listed in the USGS NEIC Monthly Summaries. Association requires matching both arrival time and azimuth of the Rayleigh waves. Regional calibration of group velocity and azimuth is required. . Large variations in both group velocity and azimuth corrections were found, as an example, signals from events in Fiji Tonga arrive with apparent group velocities of 2.9 3.5 krn/s and azimuths from 5 to + 40 degrees clockwise from true (great circle azimuth, whereas signals from Kuriles Kamchatka have velocities of 2.4 2.9 km/s and azimuths off by 35 to 0 degrees. After applying the regional corrections, surface waves are considered associated if the arrival time matches to within 0.25 km/s in apparent group velocity and the azimuth is within 30 degrees of the median expected. Over the 18 month period studied, 32% of the automatically detected surface waves were associated with events located by the Yellowknife short period array, and 34% (1591 with NEIC events; there is about 70% overlap between the two sets of events. Had the automatic detections been reported to the USGS, YKA would have ranked second (after LZH in terms of numbers of associated surface waves for the study period of April 1991 to September 1992.

Monthly energy review, August 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-08-01

The Monthly Energy Review for the month of August 1997, presents an overview of the Energy Information Administration`s recent monthly energy statistics. The statistics cover the major activities of U.S. production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors.

Atmospheric Simulations Using OGCM-Assimilation SST: Influence of the Wintertime Japan Sea on Monthly Precipitation

Directory of Open Access Journals (Sweden)

Masaru Yamamoto Naoki Hirose

2010-01-01

Full Text Available Temperature data for the Japan Sea obtained from ocean data assimilation modeling is applied to atmospheric simulations of monthly precipitation for January 2005. Because the volume of flow of the Tsushima Warm Current was large during the winter season, the sea surface temperature (SST and coastal precipitation were higher in comparison with those in 2003. In order to evaluate influence of SST on monthly precipitation, we use surface temperatures of the Japan Sea in 2003 and 2005 for comparative simulations of precipitation for January 2005. The precipitation in experiment C (using cool SST data in 2003 is smaller than that in experiment W (using warm SST data in 2005 in a large part of the sea area, since the small evaporation results from the low SST over the upstream area of northwesterly winter monsoon. In the domain of 33.67 - 45.82°N and 125.89 - 142.9°E, the averaged evaporation and precipitation in experiment C are 10% and 13% smaller than those in experiment W, respectively. About half of the difference between the precipitations observed for January 2003 and 2005 in a heavy snow area is equal to the difference between the two simulations. Our results show that the mesoscale SST difference between 2003 and 2005 is related to the local difference of monthly precipitation.

School playground surfacing and arm fractures in children: a cluster randomized trial comparing sand to wood chip surfaces.

Directory of Open Access Journals (Sweden)

Andrew W Howard

2009-12-01

Full Text Available The risk of playground injuries, especially fractures, is prevalent in children, and can result in emergency room treatment and hospital admissions. Fall height and surface area are major determinants of playground fall injury risk. The primary objective was to determine if there was a difference in playground upper extremity fracture rates in school playgrounds with wood fibre surfacing versus granite sand surfacing. Secondary objectives were to determine if there were differences in overall playground injury rates or in head injury rates in school playgrounds with wood fibre surfacing compared to school playgrounds with granite sand surfacing.The cluster randomized trial comprised 37 elementary schools in the Toronto District School Board in Toronto, Canada with a total of 15,074 students. Each school received qualified funding for installation of new playground equipment and surfacing. The risk of arm fracture from playground falls onto granitic sand versus onto engineered wood fibre surfaces was compared, with an outcome measure of estimated arm fracture rate per 100,000 student-months. Schools were randomly assigned by computer generated list to receive either a granitic sand or an engineered wood fibre playground surface (Fibar, and were not blinded. Schools were visited to ascertain details of the playground and surface actually installed and to observe the exposure to play and to periodically monitor the depth of the surfacing material. Injury data, including details of circumstance and diagnosis, were collected at each school by a prospective surveillance system with confirmation of injury details through a validated telephone interview with parents and also through collection (with consent of medical reports regarding treated injuries. All schools were recruited together at the beginning of the trial, which is now closed after 2.5 years of injury data collection. Compliant schools included 12 schools randomized to Fibar that installed

Enhancement After Myopic Small Incision Lenticule Extraction (SMILE) Using Surface Ablation.

Science.gov (United States)

Siedlecki, Jakob; Luft, Nikolaus; Kook, Daniel; Wertheimer, Christian; Mayer, Wolfgang J; Bechmann, Martin; Wiltfang, Rainer; Priglinger, Siegfried G; Sekundo, Walter; Dirisamer, Martin

2017-08-01

To report the feasibility and outcomes of surface ablation after small incision lenticule extraction (SMILE). In this retrospective evaluation of 1,963 SMILE procedures, 43 eyes (2.2%) were re-treated at three separate clinics. Of these, 40 eyes of 28 patients with a follow-up of at least 3 months were included in the analysis. During surface ablation, mitomycin C was applied for haze prevention. Spherical equivalent was -6.35 ± 1.31 diopters (D) before SMILE and -0.86 ± 0.43 D before surface ablation. Surface ablation was performed after a mean of 9.82 ± 5.27 months and resulted in a spherical equivalent of 0.03 ± 0.57 D at 3 months (P line. Corrected distance visual acuity (CDVA) remained unchanged with 0.01 ± 0.07 logMAR before versus -0.01 ± 0.05 logMAR after re-treatment (P = .99). Six eyes (15.0%) lost one line of CDVA, but final CDVA was 0.00 logMAR in four and 0.10 logMAR in two of these cases. The safety and efficacy indices were 1.06 and 0.90 at 3 months, respectively. Three of the four surface ablation profiles (Triple-A, tissue-saving algorithm, and topography-guided) resulted in equally good results, whereas enhancement with the aspherically optimized profile (ASA), used in two eyes, resulted in overcorrection (+1.38 and +1.75 D). Combined with the intraoperative application of mitomycin C, surface ablation seems to be a safe and effective method of secondary enhancement after SMILE. Due to the usually low residual myopia, the ASA profile is not recommended in these cases. [J Refract Surg. 2017;33(8):513-518.]. Copyright 2017, SLACK Incorporated.

The boundary condition for vertical velocity and its interdependence with surface gas exchange

Directory of Open Access Journals (Sweden)

A. S. Kowalski

2017-07-01

Full Text Available The law of conservation of linear momentum is applied to surface gas exchanges, employing scale analysis to diagnose the vertical velocity (w in the boundary layer. Net upward momentum in the surface layer is forced by evaporation (E and defines non-zero vertical motion, with a magnitude defined by the ratio of E to the air density, as w = E/ρ. This is true even right down at the surface where the boundary condition is w|0 = E/ρ|0 (where w|0 and ρ|0 represent the vertical velocity and density of air at the surface. This Stefan flow velocity implies upward transport of a non-diffusive nature that is a general feature of the troposphere but is of particular importance at the surface, where it assists molecular diffusion with upward gas migration (of H2O, for example but opposes that of downward-diffusing species like CO2 during daytime. The definition of flux–gradient relationships (eddy diffusivities requires rectification to exclude non-diffusive transport, which does not depend on scalar gradients. At the microscopic scale, the role of non-diffusive transport in the process of evaporation from inside a narrow tube – with vapour transport into an overlying, horizontal airstream – was described long ago in classical mechanics and is routinely accounted for by chemical engineers, but has been neglected by scientists studying stomatal conductance. Correctly accounting for non-diffusive transport through stomata, which can appreciably reduce net CO2 transport and marginally boost that of water vapour, should improve characterisations of ecosystem and plant functioning.

Developing reservoir monthly inflow forecasts using artificial intelligence and climate phenomenon information

Science.gov (United States)

Yang, Tiantian; Asanjan, Ata Akbari; Welles, Edwin; Gao, Xiaogang; Sorooshian, Soroosh; Liu, Xiaomang

2017-04-01

Reservoirs are fundamental human-built infrastructures that collect, store, and deliver fresh surface water in a timely manner for many purposes. Efficient reservoir operation requires policy makers and operators to understand how reservoir inflows are changing under different hydrological and climatic conditions to enable forecast-informed operations. Over the last decade, the uses of Artificial Intelligence and Data Mining [AI & DM] techniques in assisting reservoir streamflow subseasonal to seasonal forecasts have been increasing. In this study, Random Forest [RF), Artificial Neural Network (ANN), and Support Vector Regression (SVR) are employed and compared with respect to their capabilities for predicting 1 month-ahead reservoir inflows for two headwater reservoirs in USA and China. Both current and lagged hydrological information and 17 known climate phenomenon indices, i.e., PDO and ENSO, etc., are selected as predictors for simulating reservoir inflows. Results show (1) three methods are capable of providing monthly reservoir inflows with satisfactory statistics; (2) the results obtained by Random Forest have the best statistical performances compared with the other two methods; (3) another advantage of Random Forest algorithm is its capability of interpreting raw model inputs; (4) climate phenomenon indices are useful in assisting monthly or seasonal forecasts of reservoir inflow; and (5) different climate conditions are autocorrelated with up to several months, and the climatic information and their lags are cross correlated with local hydrological conditions in our case studies.

A study of urban heat island and its association with particulate matter during winter months over Delhi

International Nuclear Information System (INIS)

Pandey, Puneeta; Kumar, Dinesh; Prakash, Amit; Masih, Jamson; Singh, Manoj; Kumar, Surendra; Jain, Vinod Kumar; Kumar, Krishan

2012-01-01

Day and night time thermal mapping of Delhi has been done with MODIS satellite data for the months of November and December for years 2007, 2008, 2009 and 2010. The study reveals the formation of day time “cool island” over central parts of Delhi which are found to be cooler by a maximum of 4–6 °C than the surrounding rural areas. During the night time, however, the central parts of Delhi are found to be warmer by a maximum of 4–7 °C or even more than the surrounding rural areas thus confirming the formation of nocturnal urban heat island over Delhi. Measurements of solar spectral irradiance over Delhi reveal significantly lower values as compared to a rural site located south-west of Delhi, during the low wind conditions in the months of November and December. Analysis of average monthly temporal data of surface wind speed and particulate matter concentration over Delhi reveals a strong anti-correlation between wind speed and particulate matter concentration. High values of particulate matter during low wind conditions seem to favor the so called “cool island” over Delhi. Analysis of radiosonde data of 975 hPa and 850 hPa temperatures over Delhi during November and December from 1973 to 2010 reveals a warming trend at the 850 hPa level and an overall declining trend of ∆T between 975 hPa temperatures and 850 hPa temperatures, thus indicating a weakening of vertical thermal gradients over Delhi during these months. The study suggests that urban areas behave more like moderators of diurnal temperature variation in low wind conditions. - Highlights: ► Daytime cool island forms over central parts of Delhi in November and December. ► Central parts of Delhi are cooler by a maximum of 4–6 °C during daytime and warmer by a maximum of 4–7 °C during night. ► Significant negative correlations exist between daytime surface temperatures and AOD levels. ► Land use parameters have significant correlations with surface temperatures. ► The day time

Research on Land Surface Thermal-Hydrologic Exchange in Southern China under Future Climate and Land Cover Scenarios

Directory of Open Access Journals (Sweden)

Jianwu Yan

2013-01-01

Full Text Available Climate change inevitably leads to changes in hydrothermal circulation. However, thermal-hydrologic exchanging caused by land cover change has also undergone ineligible changes. Therefore, studying the comprehensive effects of climate and land cover changes on land surface water and heat exchanges enables us to well understand the formation mechanism of regional climate and predict climate change with fewer uncertainties. This study investigated the land surface thermal-hydrologic exchange across southern China for the next 40 years using a land surface model (ecosystem-atmosphere simulation scheme (EASS. Our findings are summarized as follows. (i Spatiotemporal variation patterns of sensible heat flux (H and evapotranspiration (ET under the land cover scenarios (A2a or B2a and climate change scenario (A1B are unanimous. (ii Both H and ET take on a single peak pattern, and the peak occurs in June or July. (iii Based on the regional interannual variability analysis, H displays a downward trend (10% and ET presents an increasing trend (15%. (iv The annual average H and ET would, respectively, increase and decrease by about 10% when woodland converts to the cultivated land. Through this study, we recognize that land surface water and heat exchanges are affected greatly by the future climate change as well as land cover change.

A field-trial of two restorative materials used with atraumatic restorative treatment in rural Turkey: 24-month results

Directory of Open Access Journals (Sweden)

Ertugrul Ercan

2009-08-01

Full Text Available OBJECTIVE: The purpose of this study was to investigate the clinical performance of high-strength glass ionomer cement (HSGIC and resin-modified glass ionomer (RMGIC in single and multiple surface carious cavities in the field conditions. MATERIAL AND METHODS: A split-mouth design, including ninety-one fillings placed on contra lateral molar pairs of 37 children, was used in permanent dentition. As filling materials, a HSGIC (Ketac Molar/3M ESPE and a RMGIC (Vitremer/ 3M ESPE were used with the Atraumatic Restorative Treatment (ART. Baseline and 6, 12 and 24-month evaluations of the fillings were made with standard-ART and USPHS criteria by two examiners with kappa values of 0.92 and 0.87 for both criteria. RESULTS: According to the USPHS criteria, the retention rates of RMGIC and HSGIC restorations were 100% and 80.9% for single surface, and 100% and 41.2% for multiple surface restorations after 24 months, respectively. Irrespective of surface number, RMGIC was significantly superior to HSGIC (p= 0.004, according to both standard-ART and USPHS criteria. CONCLUSION: The results indicate that RMGIC may be an alternative restorative technique in comparison to high-strength GIC applications in ART-field-trials. However, further clinical and field trials are needed to support this conclusion.

Synoptic Bi-monthly and Storm Response Water Quality Sampling in Southern Kaneohe Bay, HI 2005-2007 (NODC Accession 0060061)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Synoptic sampling including water column profiles and collected surface water samples was conducted on a bi-monthly basis throughout the rainy season(October-May)...

The tritium content of precipitation and surface water in Austria in 1984

International Nuclear Information System (INIS)

Rank, D.; Rajner, V.; Lust, G.

1985-01-01

This report includes weighted monthly 3 H-means from 23 precipitation sampling stations, 3 H-concentrations of daily precipitation samples from the station Wien-Arsenal, and 3 H-concentrations of monthly samples from 17 surface water sampling stations. (Author)

Preliminary Effects of Oral Uridine on the Ocular Surface in Dry Eye Patients

OpenAIRE

Chang, Ki Cheol; Oh, Joo Youn; In, Youn Seok; Kim, Mee Kum; Shin, Ki Cheul; Wee, Won Ryang; Lee, Jin Hak; Park, Myung Gyu

2009-01-01

We designed a randomized, double blinded, 3-months controlled prospective clinical study to investigate effects of oral uridine on the ocular surface in dry eye patients. Twenty-seven patients who diagnosed as dry eye with lower than 5 mm of wetting in the Schirmer strip, with corneal epithelial erosion and who completely followed-up till 3 months were enrolled. Corneal-conjunctival fluorescein staining, non-anesthetic Schirmer test, impression cytology, and Ocular Surface Disease Index (OSDI...

Disrupting the downward spiral of chronic pain and opioid addiction with mindfulness-oriented recovery enhancement: a review of clinical outcomes and neurocognitive targets.

Science.gov (United States)

Garland, Eric L

2014-06-01

Prescription opioid misuse and addiction among chronic pain patients are problems of growing medical and social significance. Chronic pain patients often require intervention to improve their well-being and functioning, and yet, the most commonly available form of pharmacotherapy for chronic pain is centered on opioid analgesics--drugs that have high abuse liability. Consequently, health care and legal systems are often stymied in their attempts to intervene with individuals who suffer from both pain and addiction. As such, novel, nonpharmacologic interventions are needed to complement pharmacotherapy and interrupt the cycle of behavioral escalation. The purpose of this paper is to describe how the downward spiral of chronic pain and prescription opioid misuse may be targeted by one such intervention, Mindfulness-Oriented Recovery Enhancement (MORE), a new behavioral treatment that integrates elements from mindfulness training, cognitive-behavioral therapy, and positive psychology. The clinical outcomes and neurocognitive mechanisms of this intervention are reviewed with respect to their effects on the risk chain linking chronic pain and prescription opioid misuse. Future directions for clinical and pharmacologic research are discussed.

Copper surfaces are associated with significantly lower concentrations of bacteria on selected surfaces within a pediatric intensive care unit.

Science.gov (United States)

Schmidt, Michael G; von Dessauer, Bettina; Benavente, Carmen; Benadof, Dona; Cifuentes, Paulina; Elgueta, Alicia; Duran, Claudia; Navarrete, Maria S

2016-02-01

Health care-associated infections result in significant patient morbidity and mortality. Although cleaning can remove pathogens present on hospital surfaces, those surfaces may be inadequately cleaned or recontaminated within minutes. Because of copper's inherent and continuous antimicrobial properties, copper surfaces offer a solution to complement cleaning. The objective of this study was to quantitatively assess the bacterial microbial burden coincident with an assessment of the ability of antimicrobial copper to limit the microbial burden associated with 3 surfaces in a pediatric intensive care unit. A pragmatic trial was conducted enrolling 1,012 patients from 2 high acuity care units within a 249-bed tertiary care pediatric hospital over 12 months. The microbial burden was determined from 3 frequently encountered surfaces, regardless of room occupancy, twice monthly, from 16 rooms, 8 outfitted normally and 8 outfitted with antimicrobial copper. Copper surfaces were found to be equivalently antimicrobial in pediatric settings to activities reported for adult medical intensive care units. The log10 reduction to the microbial burden from antimicrobial copper surfaced bed rails was 1.996 (99%). Surprisingly, introduction of copper objects to 8 study rooms was found to suppress the microbial burden recovered from objects assessed in control rooms by log10 of 1.863 (73%). Copper surfaces warrant serious consideration when contemplating the introduction of no-touch disinfection technologies for reducing burden to limit acquisition of HAIs. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Progress report, 24 months

DEFF Research Database (Denmark)

Juhl, Thomas Winther; Nielsen, Jakob Skov

The work performed during the past 12 months (months 13 – 24) of the project has included the conclusion of Task 1 – Fundamental Studies and Task 2 – Multimirror Cutting Head Design. Work on Task 3 – Compact Cutting Head Design, and Task 4 – Interface Design has been carried out and the tests...... of the multimirror cutting head have been started....

Progress report, 36 months

DEFF Research Database (Denmark)

Juhl, Thomas Winther; Nielsen, Jakob Skov

The work performed during the past 12 months (months 13 – 24) of the project has included the conclusion of Task 1 – Fundamental Studies and Task 2 – Multimirror Cutting Head Design. Work on Task 3 – Compact Cutting Head Design, and Task 4 – Interface Design has been carried out and the tests...... of the multimirror cutting head have been started....

Effects of phacoemulsification combined with intraocular lens implantation on ocular surface

Directory of Open Access Journals (Sweden)

Ming Li

2013-10-01

Full Text Available AIM: To explore the changes of ocular surface after phacoemulsification combined with intraocular lens implantation. METHODS: Totally 78 cases of 78 eyes with age-related cataract were collected from August 2011 to October 2012, and they underwent corneal incision phacoemulsification combined with intraocular lens implantation. The score of dry eye symptoms; tear breakup time(BUT; Schirmer Ⅰ test(SⅠtand corneal fluorescein staining were observed and recorded in 3 days before, 1 day, 1 week, 1 month, 3 and 6 months after surgery respectively. The results were analyzed statistically. RESULTS: All the subjects complained of dry eye within 1 week after surgery. Compared with 3 days before the surgery, the corneal fluorescein staining increased and the amount of tear secretion reduced statistically significant in 1 day, 1 week and 1 month(PPP>0.05, and lasted to 3 months later. CONCLUSION: Phacoemulsification combined with intraocular lens implantation has obvious effect on the ocular surface to some extent. Preventions and treatment should be taken clinically.

Surface Turbulent Fluxes, 1x1 deg Monthly Climatology, Set1 and NCEP V2c

Data.gov (United States)

National Aeronautics and Space Administration — These data are the Goddard Satellite-based Surface Turbulent Fluxes Version-2c Dataset recently produced through a MEaSURES funded project led by Dr. Chung-Lin Shie...

Hydraulique des unités d'interfluves et de bas-fond tourbeux: un exemple en zone de socle altéré (Madagascar)

Science.gov (United States)

Grillot, J. C.; Dussarrat, B.

1992-07-01

The hydrodynamics of the groundwater system of the upland granito-gneissic plateau of Madagascar is governed by the structure of the underlying aquifer. In the alteritic interfluves, the aquifer has two layers; the peat aquifer is multilayered. Groundwater levels and spring discharges observed over 3 successive years distinguish between two different types of hydraulic behaviour. (1) Under the interfluves, unconfined conditions are found in allochtonous weathered material, and semi-confined conditions in the autochtonous weathered basement. These two systems are separated by a semi-permeable clay layer. The first system responds rapidly to rainfall (approximately 15 days) whereas the second system responds more slowly (approximately 3 months). This leads to a vertical flux between the two aquifers, the direction of which depends on the season; at the beginning of the wet season the flux is downwards, but during the later part of the season the direction reverses. (2) In the low-lying regions, where sequences are superimposed, the direction of the vertical flow changes several times over a year. At the beginning of the wet season the flux is downwards, it reverses at the end of the season. A downwards flux is then observed towards the second part of the dry season. Such behaviour is only observed in the lowest third of the catchment where permeable silts take the place of less permeable peat. This pattern of fluxes suggests a close relationship between surface water and groundwater regimes, and has a major influence on the individual water balances of the two systems.

25 CFR 700.81 - Monthly housing cost.

Science.gov (United States)

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Monthly housing cost. 700.81 Section 700.81 Indians THE... Policies and Instructions Definitions § 700.81 Monthly housing cost. (a) General. The term monthly housing...) Computation of monthly housing cost for replacement dwelling. A person's monthly housing cost for a...

Object-based Dimensionality Reduction in Land Surface Phenology Classification

Directory of Open Access Journals (Sweden)

Brian E. Bunker

2016-11-01

Full Text Available Unsupervised classification or clustering of multi-decadal land surface phenology provides a spatio-temporal synopsis of natural and agricultural vegetation response to environmental variability and anthropogenic activities. Notwithstanding the detailed temporal information available in calibrated bi-monthly normalized difference vegetation index (NDVI and comparable time series, typical pre-classification workflows average a pixel’s bi-monthly index within the larger multi-decadal time series. While this process is one practical way to reduce the dimensionality of time series with many hundreds of image epochs, it effectively dampens temporal variation from both intra and inter-annual observations related to land surface phenology. Through a novel application of object-based segmentation aimed at spatial (not temporal dimensionality reduction, all 294 image epochs from a Moderate Resolution Imaging Spectroradiometer (MODIS bi-monthly NDVI time series covering the northern Fertile Crescent were retained (in homogenous landscape units as unsupervised classification inputs. Given the inherent challenges of in situ or manual image interpretation of land surface phenology classes, a cluster validation approach based on transformed divergence enabled comparison between traditional and novel techniques. Improved intra-annual contrast was clearly manifest in rain-fed agriculture and inter-annual trajectories showed increased cluster cohesion, reducing the overall number of classes identified in the Fertile Crescent study area from 24 to 10. Given careful segmentation parameters, this spatial dimensionality reduction technique augments the value of unsupervised learning to generate homogeneous land surface phenology units. By combining recent scalable computational approaches to image segmentation, future work can pursue new global land surface phenology products based on the high temporal resolution signatures of vegetation index time series.

Sensitivity of the downward to sweeping velocity ratio to the bypass flow percentage along a guide wall for downstream fish passage

Science.gov (United States)

Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

2017-01-01

Partial-depth impermeable guidance structures (or guide walls) are used as a method to assist in the downstream passage of fish at a hydroelectric facility. However, guide walls can result in a strong downward velocity causing the approaching fish to pass below the wall and into the direction of the turbine intakes. The objective of this study was to describe how the ratio of the vertical velocity to the sweeping velocity magnitude changes along the full length and depth of a guide wall under a wide range of bypass flow percentages within a power canal. This paper focused on two guide wall configurations, each set at an angle of 45 ° to the approaching flow field and at a depth of 10 and 20 ft (3.05 and 6.10 m). The hydraulic conditions upstream of each guide wall configuration were shown to be impacted by a change in the bypass flow percentage, not only near the bypass but also at upstream sections of the guide wall. Furthermore, the effect of changing the bypass flow percentage was similar for both guide wall depths. In both cases, the effect of increasing the bypass flow percentage was magnified closer to the bypass and deeper in the water column along the guide wall.

Your Child's Development: 9 Months

Science.gov (United States)

... Child's Development: 9 Months Print en español El desarrollo de su hijo: 9 meses Nine-month-olds ... item in each hand at the same time Social and Emotional Development might be fearful of strangers ...

Natural gas monthly, May 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-05-01

The Natural Gas Monthly highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. The feature article this month is ``Restructuring energy industries: Lessons from natural gas.`` 6 figs., 26 tabs.

The forcing of monthly precipitation variability over Southwest Asia during the Boreal cold season

Science.gov (United States)

Hoell, Andrew; Shukla, Shraddhanand; Barlow, Mathew; Cannon, Forest; Kelley, Colin; Funk, Christopher C.

2015-01-01

Southwest Asia, deemed as the region containing the countries of Afghanistan, Iran, Iraq and Pakistan, is water scarce and receives nearly 75% of its annual rainfall during8 the boreal cold season of November-April. The forcing of Southwest Asia precipitation has been previously examined for the entire boreal cold season from the perspective of climate variability originating over the Atlantic and tropical Indo-Pacific Oceans. Here, we examine the inter-monthly differences in precipitation variability over Southwest Asia and the atmospheric conditions directly responsible in forcing monthly November-April precipitation. Seasonally averaged November-April precipitation over Southwest Asia is significantly correlated with sea surface temperature (SST) patterns consistent with Pacific Decadal Variability (PDV), the El Nino-Southern Oscillation (ENSO) and the warming trend of SST (Trend). On the contrary, the precipitation variability during individual months of November-April are unrelated and are correlated with SST signatures that include PDV, ENSO and Trend in different combinations. Despite strong inter-monthly differences in precipitation variability during November- April over Southwest Asia, similar atmospheric circulations, highlighted by a stationary equivalent barotropic Rossby wave centered over Iraq, force the monthly spatial distributions of precipitation. Tropospheric waves on the eastern side of the equivalent barotropic Rossby wave modifies the flux of moisture and advects the mean temperature gradient, resulting in temperature advection that is balanced by vertical motions over Southwest Asia. The forcing of monthly Southwest Asia precipitation by equivalent barotropic Rossby waves is different than the forcing by baroclinic Rossby waves associated with tropically-forced-only modes of climate variability.

Your Baby's Growth: 5 Months

Science.gov (United States)

... Safe Videos for Educators Search English Español Your Baby's Growth: 5 Months KidsHealth / For Parents / Your Baby's ... a cause for concern. How Much Will My Baby Grow? By 5 months, your baby's birth weight ...

Efficacy of two-month treatment with Xiloial® eyedrops for discomfort from disposable soft contact lenses

Directory of Open Access Journals (Sweden)

Piera Versura

2010-09-01

Full Text Available Piera Versura, Vincenzo Profazio, Nicole Balducci, Emilio C CamposOphthalmology Unit, Alma Mater Studiorum University of Bologna, Bologna, ItalyPurpose: To evaluate the efficacy and tolerability of Xiloial® monodose eyedrops in the treatment of patients suffering from subjective symptoms of discomfort related to disposable soft contact lens (dSCL wear.Methods: Fifteen (12 female, three male, medium age 39 ± 9 years dSCL wearers were enrolled. Inclusion criteria were Ocular Surface Disease Index (ODSI symptom questionnaire score >12, tear film break-up time (TFBUT <10 sec, Schirmer test I >10 mm over five minutes, mild punctuate keratopathy, and conjunctival staining (Oxford grading ≤4. Monodose Xiloial eyedrops were administered three times daily for a two-month period. Patients were evaluated at enrollment, after three days of washout (baseline, and after one and two months of treatment, by OSDI score, Schirmer test I, TFBUT, ferning test, ocular surface damage (Oxford grade, and serum albumin in tears (index of passive exudation related to serum leakage.Results: At endpoint versus baseline, respectively, the mean ± standard deviation of all variables improved as follows: OSDI (8.5 ± 3 versus 20.2 ± 1.6; TFBUT (9.6 ± 1.1 versus 7.1 ± 1.0; Oxford grading (0.5 ± 0.1 versus 3.6 ± 0.8; ferning test (2 ± 1 versus 2.4 ± 0.5; and Schirmer test I (14.6 ± 1.1 versus 12 ± 2.1, with P < 0.05 for all variables (Friedman and Wilcoxon tests. Tolerability was high, with no adverse events noted.Conclusions: A two-month treatment with Xiloial showed good tolerance and appeared to reduce ocular surface damage and symptoms of discomfort.Keywords: discomfort, dry eye, disposable contact lens, biopolymer tamarind seed polysaccharide–hyaluronic acid

The tritium content of precipitation and surface water in Austria in 1986

International Nuclear Information System (INIS)

Rank, D.; Rajner, V.; Lust, G.

1987-01-01

This report includes weighted monthly 3 H-means for 23 precipitation sampling stations, 3 H-concentrations of daily precipitation samples from the station Wien-Arsenal, and 3 H-concentrations of monthly samples from 17 surface water sampling stations. 2 refs., 3 tabs., 18 figs. (Author)

A pilot study of the marginal adaptation and surface morphology of glass-cermet cements.

Science.gov (United States)

Chu, C H; King, N M; Lee, A M; Yiu, C K; Wei, S H

1996-07-01

This study investigated changes in the marginal adaptation and surface morphology of Ketac-Silver and Chelon-Silver glass-current cements over time. Dispersalloy amalgam was used as a control. Contralateral pairs of carious primary molars were restored with the test materials and amalgam. Clinical evaluations were scheduled at 12, 18, and 24 months after placement. Gold-plated replicas of the restorations were observed with scanning electron microscopy. Fractures and cracks in the surface of the Dispersalloy and Chelon-Silver increased the surface roughness; however, the damage was superficial and self-limiting in the Dispersalloy restorations, while in Chelon-Silver the fractures caused the material to break down in layers. A substantial quantity of pores, usually smaller than 50 microns in diameter, were observed throughout the surface of the Chelon-Silver restorations. The pores in the surface of Ketac-Silver were fewer and smaller. The incidence of cavomarginal breakdown increased with time. Chelon-Silver restorations had a higher rate of cavomarginal breakdown than did Ketac-Silver and Dispersalloy restorations up to 18 months. However, there was no statistically significant difference in the marginal adaptation of the three groups at 24 months.

228Ra and 228Th concentrations in GEOSECS Atlantic surface waters

International Nuclear Information System (INIS)

Li, Y.H.; Toggweiler, J.R.; Feely, H.W.

1980-01-01

An average 228 Ra flux of 0.6 +- 0.1 dpm cm -2 yr -1 from continental shelf sediments can maintain the estimated total 228 Ra inventory of about 5x10 17 dpm in Atlantic surface waters. By fitting 228 Ra and potential temperature data to Munk's vertical advection-diffusion model, upwelling rates of 17 +- 10 m yr -1 and vertical eddy diffusion coefficients of 0.4 +- 0.2 cm 2 s -1 were obtained in the upper water column of the equatorial Atlantic. The downward fluxes of particulate 228 Th across the 350-m water depth are about 0.01 to 0.04 dpm cm -2 yr -1 in the Sargasso Sea and in the regions south of 12 0 N and about 0.06 to 0.11 dpm cm -2 yr -1 in the northern temperate region (excluding the Sargasso Sea). The shorter half-removal time of 228 Th in the equatorial (10 0 S to 20 0 N) and the northern region (35 0 to 65 0 N) are related to higher biological productivity there. (author)

Petroleum marketing monthly

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-08-01

The Petroleum Marketing Monthly (PMM) provides information and statistical data on a variety of crude oils and refined petroleum products. The publication presents statistics on crude oil costs and refined petroleum products sales for use by industry, government, private sector analysts, educational institutions, and consumers. Data on crude oil include the domestic first purchase price, the f.o.b. and landed cost of imported crude oil, and the refiners` acquisition cost of crude oil. Refined petroleum product sales data include motor gasoline, distillates, residuals, aviation fuels, kerosene, and propane. The Petroleum Marketing Division, Office of Oil and Gas, Energy Information Administration ensures the accuracy, quality, and confidentiality of the published data in the Petroleum Marketing Monthly.

Petroleum marketing monthly

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-07-01

Petroleum Marketing Monthly (PPM) provides information and statistical data on a variety of crude oils and refined petroleum products. The publication presents statistics on crude oil costs and refined petroleum products sales for use by industry, government, private sector analysts, educational institutions, and consumers. Data on crude oil include the domestic first purchase price, the f.o. b. and landed cost of imported crude oil, and the refiners` acquisition cost of crude oil. Refined petroleum product sales data include motor gasoline, distillates, residuals, aviation fuels, kerosene, and propane. The Petroleum Marketing Division, Office of Oil and Gas, Energy Information Administration ensures the accuracy, quality, and confidentiality of the published data in the Petroleum Marketing Monthly.

Petroleum marketing monthly

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-02-01

The Petroleum Marketing Monthly (PMM) provides information and statistical data on a variety of crude oils and refined petroleum products. The publication presents statistics on crude oil costs and refined petroleum products sales for use by industry, government, private sector analysts, educational institutions, and consumers. Data on crude oil include the domestic first purchase price, the f.o.b. and landed cost of imported crude oil, and the refiners acquisition cost of crude oil. Refined petroleum product sales data include motor gasoline, distillates, residuals, aviation fuels, kerosene, and propane. The Petroleum Marketing Division, Office of Oil and Gas, Energy Information Administration ensures the accuracy, quality, and confidentiality of the published data in the Petroleum Marketing Monthly.

Natural gas monthly, June 1994

Energy Technology Data Exchange (ETDEWEB)

1994-06-01

The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. The feature article this month is the executive summary from Natural Gas 1994: Issues and Trends. 6 figs., 31 tabs.

Fricatives at 18 months as a measure for predicting vocabulary and grammar at 24 and 30 months.

Science.gov (United States)

Sotto, Carolyn D; Redle, Erin; Bandaranayake, Dakshika; Neils-Strunjas, Jean; Creaghead, Nancy A

2014-01-01

Language develops at variable rates in young children, yet markers for different developmental trajectories, have not been identified. Production of fricatives in words may be one marker because they are later developing sounds and contribute to syntactic production. We examined whether children who produced fricatives in words by 18 months had better vocabulary and grammar scores at 18, 24, and 30 months than children who did not. The expressive language skills of 37 toddlers who did and did not produce fricatives in words by 18 months of age were compared at 18, 24 and 30 months of age. Expressive vocabulary scores and the use of grammatical markers were significantly better for children who produced fricatives by 18 months than for those who did not. This effect was consistent across scores at 18, 24, and 30 months. The total number of consonants and total number of fricatives produced at 18 months did not significantly predict expressive vocabulary scores. Because the children who produced fricatives by 18 months demonstrated better expressive language skills than their peers who did not produce fricatives by 18 months, the early production of fricatives by toddlers may be a marker of a faster expressive language developmental trajectory. Readers will: (1) describe the relationship between early phonological development and early expressive lexical development, (2) describe the role of perceptual and motor development in speech sound the acquisition, and (3) describe the potential relationship between the production of fricatives and expressive language development. Copyright © 2014 Elsevier Inc. All rights reserved.

Responsiveness and Attention during Picture-Book Reading in 18-Month-Old to 24-Month-Old Toddlers at Risk

Science.gov (United States)

Fletcher, Kathryn L.; Perez, Andreina; Hooper, Corrie; Claussen, Angelika H.

2005-01-01

The purpose of this research was to examine the spontaneous responsiveness and attention during picture-book reading in 18-month-old to 24-month-old children from at-risk backgrounds. Twenty-five, 18-month-old children in an early intervention program were randomly assigned to a read condition or play condition for six months. At each seventh…

Validation of high-resolution aerosol optical thickness simulated by a global non-hydrostatic model against remote sensing measurements

Science.gov (United States)

Goto, Daisuke; Sato, Yousuke; Yashiro, Hisashi; Suzuki, Kentaroh; Nakajima, Teruyuki

2017-02-01

A high-performance computing resource allows us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems. The cutting-edge computational capability, which was provided by the K computer at RIKEN in Japan, enabled the authors to perform long-term, global simulations of air pollutions and clouds with unprecedentedly high horizontal resolutions. In this study, a next generation model capable of simulating global air pollutions with O(10 km) grid spacing by coupling an atmospheric chemistry model to the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) was performed. Using the newly developed model, month-long simulations for July were conducted with 14 km grid spacing on the K computer. Regarding the global distributions of aerosol optical thickness (AOT), it was found that the correlation coefficient (CC) between the simulation and AERONET measurements was approximately 0.7, and the normalized mean bias was -10%. The simulated AOT was also compared with satellite-retrieved values; the CC was approximately 0.6. The radiative effects due to each chemical species (dust, sea salt, organics, and sulfate) were also calculated and compared with multiple measurements. As a result, the simulated fluxes of upward shortwave radiation at the top of atmosphere and the surface compared well with the observed values, whereas those of downward shortwave radiation at the surface were underestimated, even if all aerosol components were considered. However, the aerosol radiative effects on the downward shortwave flux at the surface were found to be as high as 10 W/m2 in a global scale; thus, simulated aerosol distributions can strongly affect the simulated air temperature and dynamic circulation.

Ground Radiometric Method as a Tool for Determining the Surface Boundary of a Buried Bauxitic Karst

Directory of Open Access Journals (Sweden)

Kamal Kareem Ali

2011-12-01

Full Text Available Forty two ground radiometric measurements along nine traverses within a rectangular network area were taken across a bauxitic karst within the Ubaid Formation (Lower Jurassic in the Western Desert of Iraq. A 4-Channel Gamma Ray Spectrometer (GAD-6 with sodium iodide NaI (Tl crystal (GSP-4S was used in the field to measure the total radioactivity of the surface soil. Soil samples collected from the surface at each measurement point and core samples collected from a test well penetrating the karst were analyzed by Gamma ray spectrometer. The main objective of this study was to detect the hidden bauxitic karst and determine its surface boundary. The radioactivity on the surface of the karst was ranging between 60 and 80 count per second (c/s, while the background radioactivity of the Ubaid Formation, which hosts the karst, was ranging between 100 and150 c/s. Chemical weathering, especially dissolution and leaching moved uranium (238U and thorium(232Th from the overburden downward. Accordingly, these elements have been adsorbed on the surface of clay minerals and bauxite buried at a depth of about 5m causing enrichment with radioactivity. The leached overburden lack radioelements, so its radioactivity was less than background radioactivity level. The gamma ray spectroanalysis showed that the radioactivity of 238U and 232Th in the overburden was 0.5 and 3 Bq/Kg, whereas, in the bauxite and flint clay bed, it was 240 and 160 Bq/Kg respectively. Based on the radioactivity anomaly contrast on the surface, an isorad map was plotted and the karst diameter which represents low anomaly was determined to be ranging from 150 to 200m. The current study demonstrates that the ground radiometric method is quite useful for detecting the bauxitic karst and inferring its surface boundaries.

Climate Prediction Center - monthly Outlook

Science.gov (United States)

Weather Service NWS logo - Click to go to the NWS home page Climate Prediction Center Site Map News Outlooks monthly Climate Outlooks Banner OFFICIAL Forecasts June 2018 [UPDATED MONTHLY FORECASTS SERVICE ) Canonical Correlation Analysis ECCA - Ensemble Canonical Correlation Analysis Optimal Climate Normals

A trabecular metal implant 4 months after placement: clinical-histologic case report.

Science.gov (United States)

Spinato, Sergio; Zaffe, Davide; Felice, Pietro; Checchi, Luigi; Wang, Hom-Lay

2014-02-01

The aim of this case report was to histologically evaluate the behavior of a trabecular metal (TM) implant composed of titanium and spatial 3-dimensional tantalum (Ta) trabeculae. This study is the first human histologic case report of this implant. A TM implant was placed in a 54-year-old woman exhibiting moderate chronic periodontitis. After periodontal treatment, the implant was inserted under favorable clinical conditions. Patient was not seen for 4 months because of unrelated breast reduction surgery. At the surgical reopening, periimplant inflammation affecting the coronal third of the implant was observed 4 months after implant placement. With patient's consent, the implant was removed for histologic analysis. Histology highlighted a greater amount of bone in close contact with Ta trabeculae than titanium surfaces. The finding of bone formation around the Ta trabeculae suggests that trabecular metal material promotes bone ingrowth for secondary implant stability. Additional evidence is needed to confirm this observation.

Heat and turbulent kinetic energy budgets for surface layer cooling induced by the passage of Hurricane Frances (2004)

Science.gov (United States)

Huang, Peisheng; Sanford, Thomas B.; Imberger, JöRg

2009-12-01

Heat and turbulent kinetic energy budgets of the ocean surface layer during the passage of Hurricane Frances were examined using a three-dimensional hydrodynamic model. In situ data obtained with the Electromagnetic-Autonomous Profiling Explorer (EM-APEX) floats were used to set up the initial conditions of the model simulation and to compare to the simulation results. The spatial heat budgets reveal that during the hurricane passage, not only the entrainment in the bottom of surface mixed layer but also the horizontal water advection were important factors determining the spatial pattern of sea surface temperature. At the free surface, the hurricane-brought precipitation contributed a negligible amount to the air-sea heat exchange, but the precipitation produced a negative buoyancy flux in the surface layer that overwhelmed the instability induced by the heat loss to the atmosphere. Integrated over the domain within 400 km of the hurricane eye on day 245.71 of 2004, the rate of heat anomaly in the surface water was estimated to be about 0.45 PW (1 PW = 1015 W), with about 20% (0.09 PW in total) of this was due to the heat exchange at the air-sea interface, and almost all the remainder (0.36 PW) was downward transported by oceanic vertical mixing. Shear production was the major source of turbulent kinetic energy amounting 88.5% of the source of turbulent kinetic energy, while the rest (11.5%) was attributed to the wind stirring at sea surface. The increase of ocean potential energy due to vertical mixing represented 7.3% of the energy deposited by wind stress.

Electric power monthly

Energy Technology Data Exchange (ETDEWEB)

Smith, Sandra R.; Johnson, Melvin; McClevey, Kenneth; Calopedis, Stephen; Bolden, Deborah

1992-05-01

The Electric Power Monthly is prepared by the Survey Management Division; Office of Coal, Nuclear, Electric and Alternate Fuels, Energy Information Administration (EIA), Department of Energy. This publication provides monthly statistics at the national, Census division, and State levels for net generation, fuel consumption, fuel stocks, quantity and quality of fuel, cost of fuel, electricity sales, revenue, and average revenue per kilowatthour of electricity sold. Data on net generation, fuel consumption, fuel stocks, quantity and cost of fuel are also displayed for the North American Electric Reliability Council (NERC) regions. Additionally, statistics by company and plant are published in the EPM on capability of new plants, new generation, fuel consumption, fuel stocks, quantity and quality of fuel, and cost of fuel.

Validation of a Climate-Data Record of the "Clear-Sky" Surface Temperature of the Greenland Ice Sheet

Science.gov (United States)

Hall, Dorothy K.; Box, Jason E.; Koenig, Lora S.; DiGirolamo, Nicolo E.; Comiso, Josefino C.; Shuman, Christopher A.

2011-01-01

Surface temperatures on the Greenland Ice Sheet have been studied on the ground, using automatic weather station (AWS) data from the Greenland-Climate Network (GC-Net), and from analysis of satellite sensor data. Using Advanced Very High Frequency Radiometer (AVHRR) weekly surface temperature maps, warming of the surface of the Greenland Ice Sheet has been documented since 1981. We extended and refined this record using higher-resolution Moderate-Resolution Imaging Spectroradiometer (MODIS) data from March 2000 to the present. We developed a daily and monthly climate-data record (CDR) of the "clear-sky" surface temperature of the Greenland Ice Sheet using an ice-surface temperature (1ST) algorithm developed for use with MODIS data. Validation of this CDR is ongoing. MODIS Terra swath data are projected onto a polar stereographic grid at 6.25-km resolution to develop binary, gridded daily and mean-monthly 1ST maps. Each monthly map also has a color-coded image map that is available to download. Also included with the monthly maps is an accompanying map showing number of days in the month that were used to calculate the mean-monthly 1ST. This is important because no 1ST decision is made by the algorithm for cells that are considered cloudy by the internal cloud mask, so a sufficient number of days must be available to produce a mean 1ST for each grid cell. Validation of the CDR consists of several facets: 1) comparisons between ISTs and in-situ measurements; 2) comparisons between ISTs and AWS data; and 3) comparisons of ISTs with surface temperatures derived from other satellite instruments such as the Thermal Emission and Reflection Radiometer (ASTER) and Enhanced Thematic Mapper Plus (ETM+). Previous work shows that Terra MODIS ISTs are about 3 C lower than in-situ temperatures measured at Summit Camp, during the winter of 2008-09 under clear skies. In this work we begin to compare surface temperatures derived from AWS data with ISTs from the MODIS CDR.

Seasonal Variations in Surface Metabolite Composition of Fucus vesiculosus and Fucus serratus from the Baltic Sea.

Directory of Open Access Journals (Sweden)

Esther Rickert

Full Text Available Perennial macroalgae within the genus Fucus are known to exude metabolites through their outer thallus surface. Some of these metabolites have pro- and/or antifouling properties. Seasonal fluctuations of natural fouling pressure and chemical fouling control strength against micro- and macrofoulers have previously been observed in Fucus, suggesting that control strength varies with threat. To date, a study on the seasonal composition of surface associated metabolites, responsible for much of the fouling control, has not been done. We sampled individuals of the two co-occurring species F. vesiculosus and F. serratus at monthly intervals (six per species and month during a one-year field study. We analysed the chemical composition of surface associated metabolites of both Fucus species by means of gas chromatography-mass spectrometry (GC-MS to describe temporal patterns in chemical surface composition. Additionally, we correlated abiotic and biotic parameters recorded monthly within the sampled habitat with the variation in the chemical surface landscape of Fucus. Our study revealed that the chemical surface composition of both Fucus species exhibits substantial seasonal differences between spring/summer and autumn/winter months. Light and temperature explained most of the seasonal variability in surface metabolite composition of both Fucus species. A strong summerly up-regulation of eighteen saccharides and two hydroxy acids in F. vesiculosus as well as of four fatty acids and two saccharides in F. serratus was observed. We discuss how these up-regulated molecules may have a complex effect on associated microfoulers, both promoting or decreasing fouling depending on metabolite and bacterial identity. These seasonal shifts in the surface metabolome seem to exert a compound control of density and composition of the Fucus associated biofilm.

4 km NODC/RSMAS AVHRR Pathfinder Version 5.0 and 5.1 Monthly Harmonic Climatologies (1982-2008) (NODC Accession 0075098)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains a global, 4km monthly sea surface temperature climatology derived from harmonic analysis of the AVHRR Pathfinder Version 5.0 and 5.1 sea...

Simulation of Solar Radiation Incident on Horizontal and Inclined Surfaces

Directory of Open Access Journals (Sweden)

MA Basunia

2012-12-01

Full Text Available A computer model was developed to simulate the hourly, daily and monthly average of daily solar radiation on horizontal and inclined surfaces. The measured hourly and daily solar radiation was compared with simulated radiation, and favourable agreement was observed for the measured and predicted values on clear days. The measured and simulated monthly averages of total (diffuse and beam daily solar radiation were compared and a reasonable agreement was observed for a number of stations in Japan. The simulation showed that during the rice harvesting season, September to October, there is a daily average of 14.7 MJ/m2 of solar irradiation on a horizontal surface in Matsuyama, Japan. There is a similar amount of solar radiation on a horizontal surface during the major rice harvesting season, November to December, in Bangladesh. This radiation can be effectively utilized for drying rough rice and other farm crops.

The development of postural adjustments during reaching in 6-to 18-month-old infants - Evidence for two transitions

NARCIS (Netherlands)

Van der Fits, IBM; Klip, AWJ; Van Eykern, LA; Hadders-Algra, M

The present study focused on the developmental changes of postural adjustments accompanying reaching movements in healthy infants. We made a longitudinal study of ten infants between 6 and 18 months of age. During each session multiple surface electromyograms of arm, neck, trunk and leg muscles at

Geohydrology of the unsaturated zone at the burial site for low-level radioactive waste near Beatty, Nye County, Nevada

International Nuclear Information System (INIS)

Nichols, W.D.

1987-01-01

Low-level radioactive solid waste has been buried in trenches at a site near Beatty, NV, since 1962. In 1976, as part of a national program, the US Geological Survey began a study of the geohydrology of the waste burial site to provide a basis for estimating the potential for radionuclide migration in the unsaturated zone beneath the waste burial trenches. The waste burial facility is in the northern Amargosa Desert about 170 kilometers (km) northwest of Las Vegas, NV. The site is underlain by poorly stratified deposits of gravelly or silty sand and sandy gravel, and thick beds of clayey sediments. A numerical analysis demonstrated that a potential exists for deep percolation despite high annual evaporation demands, and provided predictions of the time of year and the antecedent conditions that enhance the probability of deep percolation. Soil moisture profiles obtained monthly over an 18-month period demonstrate that deep percolation does occur. Calculation of downward moisture movement through the waste trench backfill material, on the basis of simplified assumptions, suggests that moisture could have penetrated as much as 6 m below land surface from 1963, when the oldest trenches were closed, to 1980, but that the moisture requirement for such penetration far exceeded the amount of moisture actually available. Steady-state downward movement of moisture at depths greater than 10 m and beneath the waste burial trenches would be on the order of 4 cu m/1,000 yr, assuming a steady flux rate of 0.1 microcentimeter/day. 37 refs., 32 figs., 17 tab

ULTRAPLATE 30 month management report

DEFF Research Database (Denmark)

Jensen, Jens Dahl

2003-01-01

In the period from month 24 to month 30 focus has been on the work-package 3 activities concerning optimisation of the newly developed ULTRAPLATE technology towards specific industrial applications. Three main application areas have been pursued: 1) High- speed plating of lead free solder contacts...

Control of fingertip forces in young and older adults pressing against fixed low- and high-friction surfaces.

Directory of Open Access Journals (Sweden)

Kevin G Keenan

Full Text Available Mobile computing devices (e.g., smartphones and tablets that have low-friction surfaces require well-directed fingertip forces of sufficient and precise magnitudes for proper use. Although general impairments in manual dexterity are well-documented in older adults, it is unclear how these sensorimotor impairments influence the ability of older adults to dexterously manipulate fixed, low-friction surfaces in particular. 21 young and 18 older (65+ yrs adults produced maximal voluntary contractions (MVCs and steady submaximal forces (2.5 and 10% MVC with the fingertip of the index finger. A Teflon covered custom-molded splint was placed on the fingertip. A three-axis force sensor was covered with either Teflon or sandpaper to create low- and high-friction surfaces, respectively. Maximal downward forces (F(z were similar (p = .135 for young and older adults, and decreased by 15% (p<.001 while pressing on Teflon compared to sandpaper. Fluctuations in F(z during the submaximal force-matching tasks were 2.45× greater (p<.001 for older adults than in young adults, and reached a maximum when older adults pressed against the Teflon surface while receiving visual feedback. These age-associated changes in motor performance are explained, in part, by altered muscle activity from three hand muscles and out-of-plane forces. Quantifying the ability to produce steady fingertip forces against low-friction surfaces may be a better indicator of impairment and disability than the current practice of evaluating maximal forces with pinch meters. These age-associated impairments in dexterity while interacting with low-friction surfaces may limit the use of the current generation of computing interfaces by older adults.

ATSR sea surface temperature data in a global analysis with TOPEX/POSEIDON altimetry

DEFF Research Database (Denmark)

Knudsen, Per; Andersen, Ole Baltazar; Knudsen, Thomas

1996-01-01

Along Track Scanning Radiometer (ATSR) data from the ERS 1 satellite mission are used in a global analysis of the surface temperature of the oceans. The data are the low resolution 0.5 degrees by 0.5 degrees average temperatures and cover about 24 months. At global scales a significant seasonal...... variability is found. On each of the hemispheres the surface temperatures reach their maximum after summer heating. The seasonal sea level variability, as observed from TOPEX/POSEIDON, reaches its maximum 1.1-1.4 months later....

Embrittlement of MISSE 5 Polymers After 13 Months of Space Exposure

Science.gov (United States)

Guo, Aobo; Yi, Grace T.; Ashmead, Claire C.; Mitchell, Gianna G.; deGroh, Kim K.

2012-01-01

Understanding space environment induced degradation of spacecraft materials is essential when designing durable and stable spacecraft components. As a result of space radiation, debris impacts, atomic oxygen interaction, and thermal cycling, the outer surfaces of space materials degrade when exposed to low Earth orbit (LEO). The objective of this study was to measure the embrittlement of 37 thin film polymers after LEO space exposure. The polymers were flown aboard the International Space Station and exposed to the LEO space environment as part of the Materials International Space Station Experiment 5 (MISSE 5). The samples were flown in a nadir-facing position for 13 months and were exposed to thermal cycling along with low doses of atomic oxygen, direct solar radiation and omnidirectional charged particle radiation. The samples were analyzed for space-induced embrittlement using a bend-test procedure in which the strain necessary to induce surface cracking was determined. Bend-testing was conducted using successively smaller mandrels to apply a surface strain to samples placed on a semi-suspended pliable platform. A pristine sample was also tested for each flight sample. Eighteen of the 37 flight samples experienced some degree of surface cracking during bend-testing, while none of the pristine samples experienced any degree of cracking. The results indicate that 49 percent of the MISSE 5 thin film polymers became embrittled in the space environment even though they were exposed to low doses (approx.2.75 krad (Si) dose through 127 mm Kapton) of ionizing radiation.

17 CFR 31.16 - Monthly reporting requirements.

Science.gov (United States)

2010-04-01

... of business on the last business day of the month for: (i) All customer accounts, and (ii) Separately... National Futures Association, by the tenth business day of the month following the month covered by the... customers during the month for: (i) All customer accounts, and (ii) Separately for commercial leverage...

COBE-SST2 Sea Surface Temperature and Ice

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A new sea surface temperature (SST) analysis on a centennial time scale is presented. The dataset starts in 1850 with monthly 1x1 means and is periodically updated....

Understanding the behavior of carbon dioxide and surface energy fluxes in semiarid Salt Lake Valley, Utah, USA

Science.gov (United States)

Ramamurthy, Prathap

This dissertation reports the findings from the Salt Lake Valley flux study. The Salt Lake Valley flux study was designed to improve our understanding of the complex land-atmosphere interactions in urban areas. The flux study used the eddy covariance technique to quantify carbon dioxide and surface energy budget in the semiarid Salt Lake Valley. Apart from quantifying fluxes, the study has also added new insight into the nature of turbulent scalar transport in urban areas and has addressed some of the complications in using Eddy Covariance technique in urban areas. As part of this experiment, eddy fluxes of CO2 and surface energy fluxes were measured at two sites, with distinct urban landforms; One site was located in a suburban neighborhood with substantial vegetative cover, prototypical of many residential neighborhoods in the valley. The other CO2 site was in a preurban surrounding that resembled the Salt Lake Valley before it was urbanized. The two sites were intentionally chosen to illustrate the impact of urbanization on CO 2 and surface energy flux cycles. Results indicate that the suburban site acted as a sink of CO2 during the midday period due to photosynthesis and acted as a source of CO2 during the evening and nighttime periods. The vegetative cover around the suburban site also had a significant impact on the surface energy fluxes. Contribution from latent heat flux was substantially high at the suburban site during the summer months compared to sensible heat. The turbulence investigation found that the general behavior of turbulence was very much influenced by local factors and the statistics did not always obey Monin-Obukhov Similarity parameters. This investigation also found that the scalar (co)spectra observed at the suburban site were characterized by multiple peaks and were different compared to (co)spectra reported over forest and crop canopies. The study also observed multiscale CO2 transport at the suburban site during the convective period

Preliminary effects of oral uridine on the ocular surface in dry eye patients.

Science.gov (United States)

Chang, Ki Cheol; Oh, Joo Youn; In, Youn Seok; Kim, Mee Kum; Shin, Ki Cheul; Wee, Won Ryang; Lee, Jin Hak; Park, Myung Gyu

2009-08-01

We designed a randomized, double blinded, 3-months controlled prospective clinical study to investigate effects of oral uridine on the ocular surface in dry eye patients. Twenty-seven patients who diagnosed as dry eye with lower than 5 mm of wetting in the Schirmer strip, with corneal epithelial erosion and who completely followed-up till 3 months were enrolled. Corneal-conjunctival fluorescein staining, non-anesthetic Schirmer test, impression cytology, and Ocular Surface Disease Index (OSDI) were evaluated in the experimental and placebo groups at the baseline, 1 and 3 months after start of medication in a double blinded manner. Fluorescein stain score of the cornea was markedly decreased in oral uridine group compared to the placebo group at 3 months after medication (P=0.032, Mann-Whitney U test). The Schirmer wetting score for the oral uridine group was significantly increased (P=0.001, Wilcoxon signed rank test) at 3 months and its difference between two groups was statistically significant (P=0.030, Mann-Whitney U test). OSDI scores were significantly decreased at 1 and 3 months in treatment group. Oral uridine is effective in treatment of dry eyes.

Analysis of Water and Energy Budgets and Trends Using the NLDAS Monthly Data Sets

Science.gov (United States)

Vollmer, Bruce E.; Rui, Hualan; Mocko, David M.; Teng, William L.; Lei, Guang-Dih

2012-01-01

The North American Land Data Assimilation System (NLDAS) is a collaborative project between NASA GSFC, NOAA, Princeton University, and the University of Washington. NLDAS has created surface meteorological forcing data sets using the best-available observations and reanalyses. The forcing data sets are used to drive four separate land-surface models (LSMs), Mosaic, Noah, VIC, and SAC, to produce data sets of soil moisture, snow, runoff, and surface fluxes. NLDAS hourly data, accessible from the NASA GES DISC Hydrology Data Holdings Portal, http://disc.sci.gsfc.nasa.gov/hydrology/data-holdings, are widely used by various user communities in modeling, research, and applications, such as drought and flood monitoring, watershed and water quality management, and case studies of extreme events. More information is available at http://ldas.gsfc.nasa.gov/. To further facilitate analysis of water and energy budgets and trends, NLDAS monthly data sets have been recently released by NASA GES DISC.

Measurement of Optic Disc Cup Surface Depth Using Cirrus HD-OCT.

Science.gov (United States)

Kim, Young Kook; Ha, Ahnul; Lee, Won June; Jeoung, Jin Wook; Park, Ki Ho

2017-12-01

To introduce the measurement method of optic disc cup surface depth using spectral-domain optical coherence tomography (SD-OCT) and then evaluate the rates of cup surface depression at 3 different stages of glaucoma. We retrospectively identified 52 eyes with preperimetric glaucoma, 56 with mild-or-moderate glaucoma and 50 with severe glaucoma and followed them for at least 48 months. Eyes were imaged using SD-OCT (Cirrus HD-OCT) at 12-month intervals. The mean cup surface depth was calculated using the following formula: Cup volume/(disc area×average cup-to-disc ratio)-200 μm. The rates of mean cup surface depression (μm/y) were significantly greater in mild-or-moderate glaucoma (-7.96±1.03) than in preperimetric (-3.11±0.61) and severe glaucoma (-0.70±0.12; all Pcup surface depression (%/y) were significantly greater than those of average of retinal nerve fiber layer (RNFL) thinning (%/y) in preperimetric glaucoma (-1.64±0.12 vs. -1.11±0.07; Pcup surface depth changed slower than did average RNFL thickness (-0.64±0.06 vs. -0.75±0.08%/y; Pcup surface depth changed faster than did the RNFL thickness. These results signify the possibility that SD-OCT-based estimation of cup surface depth might be useful for monitoring of glaucoma development and progression.

Synoptic Bi-monthly and Storm Response Water Quality Sampling in Southern Kaneohe Bay, HI November 2007 - April 2009 (NODC Accession 0062644)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Synoptic sampling including water column profiles and collected surface water samples was conducted on a bi-monthly basis throughout the rainy season(October-May)...

Digging the METEOSAT Treasure—3 Decades of Solar Surface Radiation

Directory of Open Access Journals (Sweden)

Richard Müller

2015-06-01

Full Text Available Solar surface radiation data of high quality is essential for the appropriate monitoring and analysis of the Earth's radiation budget and the climate system. Further, they are crucial for the efficient planning and operation of solar energy systems. However, well maintained surface measurements are rare in many regions of the world and over the oceans. There, satellite derived information is the exclusive observational source. This emphasizes the important role of satellite based surface radiation data. Within this scope, the new satellite based CM-SAF SARAH (Solar surfAce RAdiation Heliosat data record is discussed as well as the retrieval method used. The SARAH data are retrieved with the sophisticated SPECMAGIC method, which is based on radiative transfer modeling. The resulting climate data of solar surface irradiance, direct irradiance (horizontal and direct normal and clear sky irradiance are covering 3 decades. The SARAH data set is validated with surface measurements of the Baseline Surface Radiation Network (BSRN and of the Global Energy and Balance Archive (GEBA. Comparison with BSRN data is performed in order to estimate the accuracy and precision of the monthly and daily means of solar surface irradiance. The SARAH solar surface irradiance shows a bias of 1.3 \\(W/m^2\\ and a mean absolute bias (MAB of 5.5 \\(W/m^2\\ for monthly means. For direct irradiance the bias and MAB is 1 \\(W/m^2\\ and 8.2 \\(W/m^2\\ respectively. Thus, the uncertainty of the SARAH data is in the range of the uncertainty of ground based measurements. In order to evaluate the uncertainty of SARAH based trend analysis the time series of SARAH monthly means are compared to GEBA. It has been found that SARAH enables the analysis of trends with an uncertainty of 1 \\(W/m^2/dec\\; a remarkable good result for a satellite based climate data record. SARAH has been also compared to its legacy version, the satellite based CM-SAF MVIRI climate data record. Overall

Predicting Salmonella populations from biological, chemical, and physical indicators in Florida surface waters.

Science.gov (United States)

McEgan, Rachel; Mootian, Gabriel; Goodridge, Lawrence D; Schaffner, Donald W; Danyluk, Michelle D

2013-07-01

Coliforms, Escherichia coli, and various physicochemical water characteristics have been suggested as indicators of microbial water quality or index organisms for pathogen populations. The relationship between the presence and/or concentration of Salmonella and biological, physical, or chemical indicators in Central Florida surface water samples over 12 consecutive months was explored. Samples were taken monthly for 12 months from 18 locations throughout Central Florida (n = 202). Air and water temperature, pH, oxidation-reduction potential (ORP), turbidity, and conductivity were measured. Weather data were obtained from nearby weather stations. Aerobic plate counts and most probable numbers (MPN) for Salmonella, E. coli, and coliforms were performed. Weak linear relationships existed between biological indicators (E. coli/coliforms) and Salmonella levels (R(2) Florida surface water through logistic regression.

The Relationships between Tropical Pacific and Atlantic SST and Northeast Brazil Monthly Precipitation.

Science.gov (United States)

Bertacchi Uvo, Cintia; Repelli, Carlos A.; Zebiak, Stephen E.; Kushnir, Yochanan

1998-04-01

The monthly patterns of northeast Brazil (NEB) precipitation are analyzed in relation to sea surface temperature (SST) in the tropical Pacific and Atlantic Oceans, using singular value decomposition. It is found that the relationships between precipitation and SST in both basins vary considerably throughout the rainy season (February-May). In January, equatorial Pacific SST is weakly correlated with precipitation in small areas of southern NEB, but Atlantic SST shows no significant correlation with regional precipitation. In February, Pacific SST is not well related to precipitation, but south equatorial Atlantic SST is positively correlated with precipitation over the northern Nordeste, the latter most likely reflecting an anomalously early (or late) southward migration of the ITCZ precipitation zone. During March, equatorial Pacific SST is negatively correlated with Nordeste precipitation, but no consistent relationship between precipitation and Atlantic SST is found. Atlantic SST-precipitation correlations for April and May are the strongest found among all months or either ocean. Precipitation in the Nordeste is positively correlated with SST in the south tropical Atlantic and negatively correlated with SST in the north tropical Atlantic. These relationships are strong enough to determine the structure of the seasonal mean SST-precipitation correlations, even though the corresponding patterns for the earlier months of the season are quite different. Pacific SST-precipitation correlations for April and May are similar to those for March. Extreme wet (dry) years for the Nordeste occur when both Pacific and Atlantic SST patterns for April and May occur simultaneously. A separate analysis reinforces previous findings in showing that SST in the tropical Pacific and the northern tropical Atlantic are positively correlated and that tropical Pacific-south Atlantic correlations are negligible.Time-lagged analyses show the potential for forecasting either seasonal mean

Mapping monthly rainfall erosivity in Europe.

Science.gov (United States)

Ballabio, Cristiano; Borrelli, Pasquale; Spinoni, Jonathan; Meusburger, Katrin; Michaelides, Silas; Beguería, Santiago; Klik, Andreas; Petan, Sašo; Janeček, Miloslav; Olsen, Preben; Aalto, Juha; Lakatos, Mónika; Rymszewicz, Anna; Dumitrescu, Alexandru; Tadić, Melita Perčec; Diodato, Nazzareno; Kostalova, Julia; Rousseva, Svetla; Banasik, Kazimierz; Alewell, Christine; Panagos, Panos

2017-02-01

Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part of Britain and Ireland) in May and the highest values are registered during summer months. Starting from September, R-factor has a decreasing trend. The mean rainfall erosivity in summer is almost 4 times higher (315MJmmha -1 h -1 ) compared to winter (87MJmmha -1 h -1 ). The Cubist model has been selected among various statistical models to perform the spatial interpolation due to its excellent performance, ability to model non-linearity and interpretability. The monthly prediction is an order more difficult than the annual one as it is limited by the number of covariates and, for consistency, the sum of all months has to be close to annual erosivity. The performance of the Cubist models proved to be generally high, resulting in R 2 values between 0.40 and 0.64 in cross-validation. The obtained months show an increasing trend of erosivity occurring from winter to summer starting from western to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive events. Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be

Sea surface temperature anomalies in the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

RameshKumar, M.R.

temperature anomalies for the above regions respectively. An analysis has shown that most of the short duration anomalies (i.e., anomalies with periods less than 4 months) are driven by the surface heat fluxes. The medium duration anomalies (i.e., anomalies...

Surface Turbulent Fluxes, 1x1 deg Monthly Grid, Set1 and Interpolated Data V2c

Data.gov (United States)

National Aeronautics and Space Administration — These data are the Goddard Satellite-based Surface Turbulent Fluxes Version-2c Dataset recently produced through a MEaSUREs funded project led by Dr. Chung-Lin Shie...

Electric Power Monthly, July 1990

Energy Technology Data Exchange (ETDEWEB)

1990-10-12

The Electric Power Monthly (EPM) is prepared by the Electric Power Division; Office of Coal, Nuclear, Electric and Alternate Fuels, Energy Information Administration (EIA), Department of Energy. This publication provides monthly statistics at the national, Census division, and State levels for net generation, fuel consumption, fuel stocks, quantity and quality of fuel, cost of fuel, electricity sales, and average revenue per kilowatthour of electricity sold. Data on net generation are also displayed at the North American Electric Reliability Council (NERC) region level. Additionally, company and plant level information are published in the EPM on capability of new plants, net generation, fuel consumption, fuel stocks, quantity and quality of fuel, and cost in fuel. Quantity, quality, and cost of fuel data lag the net generation, fuel consumption, fuel stocks, electricity sales, and average revenue per kilowatthour data by 1 month. This difference in reporting appears in the national, Census division, and State level tables. However, at the plant level, all statistics presented are for the earlier month for the purpose of comparison. 12 refs., 4 figs., 48 tabs.

U.S. Monthly Climate Normals (1971-2000)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — U.S. Monthly Climate Normals (1971-2000) (DSI-9641C) include climatological normals based on monthly maximum, minimum, and mean temperature and monthly total...

A 19m Deep Well – a Downward Thermal Diffusion Cloud Chamber?

OpenAIRE

Holub, R.F.

2013-01-01

An unusual phenomenon, first observed on a clear summer day after several rainy days, were droplets constantly hitting the water surface in a 19 m deep and 2.4 m diameter water well. This droplet formation was occurring during the night as well. Since the droplet formation was near continuous, we called it “the eternal rain”. The water well is about 230 years old and located in the Benedictine monastery in Broumov, Czech Republic.

Investigations by the surface photo-E. M. F. method of the effect of low temperature vacuum baking of an Si(111) surface

Energy Technology Data Exchange (ETDEWEB)

Dlugosz, B.; Kochowski, S.

1982-02-26

Investigations of the effect of low temperature vacuum baking on the surface potential of silicon are reported. The surface potential Vsub(s0) was measured by the surface photo-e.m.f. method. No noticeable changes in Vsub(s0) occurred after baking of samples which had been freshly etched in HF for 2 h in a vacuum of 6.6 x 10/sup -3/ Pa (5 x 10/sup -5/ Torr) at temperatures of 573, 623 and 723 K. Radical changes were observed when the samples had been aged in air for 2 months before vacuum baking. These results suggest that the direction and the value of the surface potential changes during vacuum baking are determined by the initial surface state.

Time lag between the tropopause height and the levels of 7Be concentration in near surface air

Science.gov (United States)

Ioannidou, A.; Vasileiadis, A.; Melas, D.

2012-04-01

The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62' N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

Monthly energy review, January 1999

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-01-01

The Monthly Energy Review (MER) presents an overview of the Energy Information Administration`s recent monthly energy statistics. The statistics cover the major activities of US production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors. 37 figs., 61 tabs.

Monthly energy review, July 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-07-01

The Monthly Energy Review (MER) presents an overview of the Energy Information Administration`s recent monthly energy statistics. The statistics cover the major activities of US production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors. 37 figs. 73 tabs.

Monthly energy review, May 1999

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-05-01

The Monthly Energy Review (MER) presents an overview of the Energy Information Administration`s recent monthly energy statistics. The statistics cover the major activities of US production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors. 37 figs., 61 tabs.

Monthly energy review, March 1999

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

The Monthly Energy Review (MER) presents an overview of the Energy Information Administration`s recent monthly energy statistics. The statistics cover the major activities of US production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors. 37 figs., 74 tabs.