WorldWideScience

Sample records for varying solution conditions

  1. Analytical solution for multi-species contaminant transport in finite media with time-varying boundary conditions

    Science.gov (United States)

    Most analytical solutions available for the equations governing the advective-dispersive transport of multiple solutes undergoing sequential first-order decay reactions have been developed for infinite or semi-infinite spatial domains and steady-state boundary conditions. In this work we present an ...

  2. Corrosion study of API 5L x-series pipeline steels in 3.5% NaCl solution under varying conditions

    International Nuclear Information System (INIS)

    Shahid, M.; Qureshi, M.I.; Farooq, M.U.; Khan, M.I.

    2003-01-01

    Pipelines provide convenient and efficient means for mass transportation of variety of fluids, such as oil and gas, over varying distances. In the last two decades or so, pipeline designers focused mainly on the usage of larger sizes and higher operating pressures for achieving higher transportation efficiency. This has been accomplished through the provision of steels with progressive increase in yield strength coupled with good weldability and sufficient toughness to restrict crack propagation. In addition to higher strength and toughness, developing pipeline technologies have required improved resistance to corrosion, which has been tried with specific alloy additions and special control over non-metallic inclusions. Corrosion investigations were carried out on various grades of pipeline steels (API 5L X-46, X-52, X-56, X-60 and X- 70) under varying environmental conditions. This paper describes the results pertaining to corrosion behavior of the steels in 3.5% NaCl solutions in stagnant, turbulent and deaerated conditions. It was found that all grades corrode in this solution and their corrosion potentials and corrosion currents are in close vicinity of each other. Turbulent solutions, however, have shown an increase in corrosion rates whereas deaeration has revealed a relative decrease in aggressivity of the electrolyte. (author)

  3. Automatically varying the composition of a mixed refrigerant solution for single mixed refrigerant LNG (liquefied natural gas) process at changing working conditions

    International Nuclear Information System (INIS)

    Xu, Xiongwen; Liu, Jinping; Cao, Le; Pang, Weiqiang

    2014-01-01

    The SMR (single mixed refrigerant) process is widely used in the small- and medium-scale liquefaction of NG (natural gas). Operating the MR (mixed-refrigerant) process outside of the design specifications is difficult but essential to save energy. Nevertheless, it is difficult to realize because the process needs to alter the working refrigerant composition. To address this challenge, this study investigated the performance diagnosis mechanism for SMR process. A control strategy was then proposed to control the changes in working refrigerant composition under different working conditions. This strategy separates the working refrigerant flow in the SMR process into three flows through two phase separators before it flows into the cold box. The first liquid flow is rich in the high-temperature component (isopentane). The second liquid flow is rich in the middle-temperature components (ethylene and propane), and the gas flow is rich in the low-temperature components (nitrogen and methane). By adjusting the flow rates, it is easy to decouple the control variables and automate the system. Finally, this approach was validated by process simulation and shown to be highly adaptive and exergy efficient in response to changing working conditions. - Highlights: • The performance diagnosis mechanism of SMR LNG process is studied. • A measure to automatically change the operation composition as per the working conditions is proposed for SMR process. • SMR process simulation is performed to verify the validity of the control solution. • The control solution notably improves the energy efficiency of SMR process at changing working condition

  4. One-dimensional radionuclide transport under time-varying conditions

    International Nuclear Information System (INIS)

    Gelbard, F.; Olague, N.E.; Longsine, D.E.

    1990-01-01

    This paper discusses new analytical and numerical solutions presented for one-dimensional radionuclide transport under time-varying fluid-flow conditions including radioactive decay. The analytical solution assumes that all radionuclides have identical retardation factors, and is limited to instantaneous releases. The numerical solution does not have these limitations, but is tested against the limiting case given for the analytical solution. Reasonable agreement between the two solutions was found. Examples are given for the transport of a three-member radionuclide chain transported over distances and flow rates comparable to those reported for Yucca Mountain, the proposed disposal site for high-level nuclear waste

  5. Panorama 2011: Refining: varying conditions by region

    International Nuclear Information System (INIS)

    Silva, C.

    2011-01-01

    The economic crisis has further weakened a sector that was already facing difficulties, if we look beyond the flush period (2005-2008) when, buoyed by strong demand, margins remained high and refiners could generate profits while maintaining a healthy level of activity. Falling demand and increased over-capacity in some regions - the immediate consequences of the deteriorating economic conditions over the past two years - have led to declining margins and to financial accounts being in the red. The adoption of increasingly stringent emissions standards and product specifications, burdensome regulatory requirements for refineries (for combating local pollution and reducing greenhouse gas emissions), stiffer competition from new fuels: all of these structural factors are weakening the sector, especially in industrialized nations with their more rigorous regulatory compliance. In this generally gloomy climate, numerous new projects are still being envisaged - although many have recently been postponed and tend to be concentrated in developing countries. (author)

  6. Explicit analytical solution of a pendulum with periodically varying length

    International Nuclear Information System (INIS)

    Yang Tianzhi; Fang Bo; Li Song; Huang Wenhu

    2010-01-01

    A pendulum with periodically varying length is an interesting physical system. It has been studied by some researchers using traditional perturbation methods (for example, the averaging method). But due to the limitation of the conventional perturbation methods, the solutions are not valid for long-term prediction of the pendulum. In this paper, we use the homotopy analysis method to explore the approximate solution to this system. The method can easily self-adjust and control the convergence region. By applying the method to the governing equation of the pendulum, we obtain the approximation solution in a closed form. It is shown by the numerical method that the homotopy analysis method supplies a more accurate analytical solution for predicting the long-term behaviour of the pendulum. We believe that this system may be a good example for undergraduate and graduate students for better understanding of nonlinear oscillations.

  7. Almost Periodic Solution for Memristive Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Huaiqin Wu

    2013-01-01

    Full Text Available This paper is concerned with the dynamical stability analysis for almost periodic solution of memristive neural networks with time-varying delays. Under the framework of Filippov solutions, by applying the inequality analysis techniques, the existence and asymptotically almost periodic behavior of solutions are discussed. Based on the differential inclusions theory and Lyapunov functional approach, the stability issues of almost periodic solution are investigated, and a sufficient condition for the existence, uniqueness, and global exponential stability of the almost periodic solution is established. Moreover, as a special case, the condition which ensures the global exponential stability of a unique periodic solution is also presented for the considered memristive neural networks. Two examples are given to illustrate the validity of the theoretical results.

  8. Contact Dynamics of EHL Contacts under Time Varying Conditions

    NARCIS (Netherlands)

    Venner, Cornelis H.; Popovici, G.; Wijnant, Ysbrand H.; Dalmaz, G.; Lubrecht, A.A.; Priest, M

    2004-01-01

    By means of numerical simulations of two situations with time varying operating conditions it is shown that the dynamic behaviour of Elasto-Hydrodynamically Lubricated contacts in terms of vibrations can be characterized as: Changes in the mutual approach lead to film thickness changes in the inlet

  9. Respiratory clearance of aerosolized radioactive solutes of varying molecular weight

    International Nuclear Information System (INIS)

    Huchon, G.J.; Montgomery, A.B.; Lipavsky, A.; Hoeffel, J.M.; Murray, J.F.

    1987-01-01

    To determine the influence of varying molecular weight (mol wt) on respiratory clearance of aerosolized solutes, we studied eight radiopharmaceuticals, each administered to four dogs: sodium /sup 99m/Tc pertechnetate (TcO4), /sup 99m/Tc glucoheptonate ([/sup 99m/Tc]GH), 51Cr-ethylenedinitrotetraacetate ([51Cr]EDTA), /sup 99m/Tc diethylenetriaminepentaacetate ([99mTc] DTPA), 111 In diethylenetriaminepentaacetate ([ 111 In]DTPA), 67 Ga desferoxaminemesylate ([ 67 Ga]DFOM), /sup 99m/Tc dextran ([/sup 99m/Tc]DX) and 111 In transferrin ([ 111 In]TF). After aerosolization (0.8 m MMD, 2.4 GSD), clearance was determined for 30 min and then corrected by intravenous injection for nonairspace radioactivity. In-TF clearance (0.11 +/- 0.10%/min) was lower than TcO4 (6.32 +/- 0.62%/min), [/sup 99m/Tc]GH (1.50 +/- 0.37%/min), [ 51 Cr]EDTA (2.38 +/- 1.02%/min), [/sup 99m/Tc]DTPA (3.51 +/- 0.40%/min), [ 111 In]DTPA (2.35 +/- 0.42%/min), [ 67 Ga] DFOM (1.99 +/- 0.49%/min) and [/sup 99m/Tc]DX (1.81 +/- 0.75%/min) clearances (p less than 0.001). TcO4 clearance was higher than others (p less than 0.001). Technetium binding to DX was unsatisfactory; aerosolization caused unbinding from DTPA. We conclude that respiratory clearance of large mol wt solutes within 30 min is negligible and, that clearance of molecules between 347-5099 daltons differs greatly, suggesting that binding and/or intrapulmonary retention affect transfer

  10. Vibration condition monitoring of planetary gearbox under varying external load

    Energy Technology Data Exchange (ETDEWEB)

    Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

    2009-01-15

    The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

  11. Conditional CAPM: Time-varying Betas in the Brazilian Market

    Directory of Open Access Journals (Sweden)

    Frances Fischberg Blank

    2014-10-01

    Full Text Available The conditional CAPM is characterized by time-varying market beta. Based on state-space models approach, beta behavior can be modeled as a stochastic process dependent on conditioning variables related to business cycle and estimated using Kalman filter. This paper studies alternative models for portfolios sorted by size and book-to-market ratio in the Brazilian stock market and compares their adjustment to data. Asset pricing tests based on time-series and cross-sectional approaches are also implemented. A random walk process combined with conditioning variables is the preferred model, reducing pricing errors compared to unconditional CAPM, but the errors are still significant. Cross-sectional test show that book-to-market ratio becomes less relevant, but past returns still capture cross-section variation

  12. A few remarks on Poincare-Perron solutions and regularly varying solutions

    Czech Academy of Sciences Publication Activity Database

    Řehák, Pavel

    2016-01-01

    Roč. 66, č. 6 (2016), s. 1297-1318 ISSN 0139-9918 Institutional support: RVO:67985840 Keywords : Perron theorem * regularly varying solution * linear differential equation Subject RIV: BA - General Mathematics Impact factor: 0.346, year: 2016 https://www.degruyter.com/view/j/ms.2016.66.issue-6/ms-2016-0224/ms-2016-0224. xml ?format=INT

  13. Atmospheric particle formation in spatially and temporally varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lauros, J.

    2011-07-01

    Atmospheric particles affect the radiation balance of the Earth and thus the climate. New particle formation from nucleation has been observed in diverse atmospheric conditions but the actual formation path is still unknown. The prevailing conditions can be exploited to evaluate proposed formation mechanisms. This study aims to improve our understanding of new particle formation from the view of atmospheric conditions. The role of atmospheric conditions on particle formation was studied by atmospheric measurements, theoretical model simulations and simulations based on observations. Two separate column models were further developed for aerosol and chemical simulations. Model simulations allowed us to expand the study from local conditions to varying conditions in the atmospheric boundary layer, while the long-term measurements described especially characteristic mean conditions associated with new particle formation. The observations show statistically significant difference in meteorological and back-ground aerosol conditions between observed event and non-event days. New particle formation above boreal forest is associated with strong convective activity, low humidity and low condensation sink. The probability of a particle formation event is predicted by an equation formulated for upper boundary layer conditions. The model simulations call into question if kinetic sulphuric acid induced nucleation is the primary particle formation mechanism in the presence of organic vapours. Simultaneously the simulations show that ignoring spatial and temporal variation in new particle formation studies may lead to faulty conclusions. On the other hand, the theoretical simulations indicate that short-scale variations in temperature and humidity unlikely have a significant effect on mean binary water sulphuric acid nucleation rate. The study emphasizes the significance of mixing and fluxes in particle formation studies, especially in the atmospheric boundary layer. The further

  14. Analytical solutions of advection-dispersion equation for varying ...

    African Journals Online (AJOL)

    Analytical solutions are obtained for a one-dimensional advection–dispersion equation with variable coefficients in a longitudinal domain. Two cases are considered. In the first one the solute dispersion is time dependent along a uniform flow in a semi-infinite domain while in the second case the dispersion and the velocity ...

  15. A thermal model for photovoltaic panels under varying atmospheric conditions

    International Nuclear Information System (INIS)

    Armstrong, S.; Hurley, W.G.

    2010-01-01

    The response of the photovoltaic (PV) panel temperature is dynamic with respect to the changes in the incoming solar radiation. During periods of rapidly changing conditions, a steady state model of the operating temperature cannot be justified because the response time of the PV panel temperature becomes significant due to its large thermal mass. Therefore, it is of interest to determine the thermal response time of the PV panel. Previous attempts to determine the thermal response time have used indoor measurements, controlling the wind flow over the surface of the panel with fans or conducting the experiments in darkness to avoid radiative heat loss effects. In real operating conditions, the effective PV panel temperature is subjected to randomly varying ambient temperature and fluctuating wind speeds and directions; parameters that are not replicated in controlled, indoor experiments. A new thermal model is proposed that incorporates atmospheric conditions; effects of PV panel material composition and mounting structure. Experimental results are presented which verify the thermal behaviour of a photovoltaic panel for low to strong winds.

  16. Bioventing of gasoline-contaminated soil under varied laboratory conditions

    International Nuclear Information System (INIS)

    Hallman, M.; Shewfelt, K.; Lee, H.; Zytner, R.G.

    2002-01-01

    Bioventing is becoming a popular in situ soil remediation technology for the treatment of hydrocarbon-contaminated soil. Bioventing relies on enhancing the growth of indigenous microorganisms, which can mineralize the contaminant in the presence of sufficient nutrients. Although bioventing is currently being used as a remediation technology, there are some important questions that remain to be answered in order to optimize the process. These questions include the optimum soil moisture content, type and amount of nutrients necessary, and the best means of producing these conditions in the field. To address these questions, two distinct phases of experiments were conducted. The first experimental phase was designed to determine the optimum moisture content, C:N ratio and form of nitrogen supply for this soil. Using approximately 200g of contaminated soil in each of a series of sealed respirometers, microbial degradation of gasoline under bioventing conditions was quantified for C:N ratios of 5, 10 and 20:1, using varying mixtures of NH 4 + - and NO 3 - -N. The results of the studies indicated that the optimum soil moisture content was 15 wt%, with a C:N ratio of 10:1, using a 100% ammonium application. Using the results of the first phase, a second phase of laboratory research was initiated. Five mesoscale reactors have been developed to simulate the bioventing process that takes place in the field. These reactors are filled with approximately 4kg of gasoline-contaminated soil. The initial results are favourable. (author)

  17. Estimation of thermal sensation during varied air temperature conditions.

    Science.gov (United States)

    Katsuura, T; Tabuchi, R; Iwanaga, K; Harada, H; Kikuchi, Y

    1998-03-01

    Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.

  18. Brief communication: A nonlinear self-similar solution to barotropic flow over varying topography

    Science.gov (United States)

    Ibanez, Ruy; Kuehl, Joseph; Shrestha, Kalyan; Anderson, William

    2018-03-01

    Beginning from the shallow water equations (SWEs), a nonlinear self-similar analytic solution is derived for barotropic flow over varying topography. We study conditions relevant to the ocean slope where the flow is dominated by Earth's rotation and topography. The solution is found to extend the topographic β-plume solution of Kuehl (2014) in two ways. (1) The solution is valid for intensifying jets. (2) The influence of nonlinear advection is included. The SWEs are scaled to the case of a topographically controlled jet, and then solved by introducing a similarity variable, η = cxnxyny. The nonlinear solution, valid for topographies h = h0 - αxy3, takes the form of the Lambert W-function for pseudo velocity. The linear solution, valid for topographies h = h0 - αxy-γ, takes the form of the error function for transport. Kuehl's results considered the case -1 ≤ γ < 1 which admits expanding jets, while the new result considers the case γ < -1 which admits intensifying jets and a nonlinear case with γ = -3.

  19. Periodic solution for state-dependent impulsive shunting inhibitory CNNs with time-varying delays.

    Science.gov (United States)

    Şaylı, Mustafa; Yılmaz, Enes

    2015-08-01

    In this paper, we consider existence and global exponential stability of periodic solution for state-dependent impulsive shunting inhibitory cellular neural networks with time-varying delays. By means of B-equivalence method, we reduce these state-dependent impulsive neural networks system to an equivalent fix time impulsive neural networks system. Further, by using Mawhin's continuation theorem of coincide degree theory and employing a suitable Lyapunov function some new sufficient conditions for existence and global exponential stability of periodic solution are obtained. Previous results are improved and extended. Finally, we give an illustrative example with numerical simulations to demonstrate the effectiveness of our theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Thermal shock behaviour of different tungsten grades under varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wirtz, Oliver Marius

    2012-07-19

    Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm{sup -2} at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced

  1. Thermal shock behaviour of different tungsten grades under varying conditions

    International Nuclear Information System (INIS)

    Wirtz, Oliver Marius

    2012-01-01

    Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm -2 at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced damages

  2. Stability of Almost Periodic Solution for a General Class of Discontinuous Neural Networks with Mixed Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    2013-01-01

    Full Text Available The global exponential stability issues are considered for almost periodic solution of the neural networks with mixed time-varying delays and discontinuous neuron activations. Some sufficient conditions for the existence, uniqueness, and global exponential stability of almost periodic solution are achieved in terms of certain linear matrix inequalities (LMIs, by applying differential inclusions theory, matrix inequality analysis technique, and generalized Lyapunov functional approach. In addition, the existence and asymptotically almost periodic behavior of the solution of the neural networks are also investigated under the framework of the solution in the sense of Filippov. Two simulation examples are given to illustrate the validity of the theoretical results.

  3. Hydrodynamic mean-field solutions of 1D exclusion processes with spatially varying hopping rates

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, Greg; O' Brien, John; Chou, Tom [Department of Biomathematics and Institute for Pure and Applied Mathematics, UCLA, Los Angeles, CA 90095 (United States)

    2006-03-10

    We analyse the open boundary partially asymmetric exclusion process with smoothly varying internal hopping rates in the infinite-size, mean-field limit. The mean-field equations for particle densities are written in terms of Ricatti equations with the steady-state current J as a parameter. These equations are solved both analytically and numerically. Upon imposing the boundary conditions set by the injection and extraction rates, the currents J are found self-consistently. We find a number of cases where analytic solutions can be found exactly or approximated. Results for J from asymptotic analyses for slowly varying hopping rates agree extremely well with those from extensive Monte Carlo simulations, suggesting that mean-field currents asymptotically approach the exact currents in the hydrodynamic limit, as the hopping rates vary slowly over the lattice. If the forward hopping rate is greater than or less than the backward hopping rate throughout the entire chain, the three standard steady-state phases are preserved. Our analysis reveals the sensitivity of the current to the relative phase between the forward and backward hopping rate functions.

  4. Hydrodynamic mean-field solutions of 1D exclusion processes with spatially varying hopping rates

    International Nuclear Information System (INIS)

    Lakatos, Greg; O'Brien, John; Chou, Tom

    2006-01-01

    We analyse the open boundary partially asymmetric exclusion process with smoothly varying internal hopping rates in the infinite-size, mean-field limit. The mean-field equations for particle densities are written in terms of Ricatti equations with the steady-state current J as a parameter. These equations are solved both analytically and numerically. Upon imposing the boundary conditions set by the injection and extraction rates, the currents J are found self-consistently. We find a number of cases where analytic solutions can be found exactly or approximated. Results for J from asymptotic analyses for slowly varying hopping rates agree extremely well with those from extensive Monte Carlo simulations, suggesting that mean-field currents asymptotically approach the exact currents in the hydrodynamic limit, as the hopping rates vary slowly over the lattice. If the forward hopping rate is greater than or less than the backward hopping rate throughout the entire chain, the three standard steady-state phases are preserved. Our analysis reveals the sensitivity of the current to the relative phase between the forward and backward hopping rate functions

  5. Global Exponential Stability of Positive Almost Periodic Solutions for a Fishing Model with a Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2014-01-01

    Full Text Available This paper is concerned with a nonautonomous fishing model with a time-varying delay. Under proper conditions, we employ a novel argument to establish a criterion on the global exponential stability of positive almost periodic solutions of the model with almost periodic coefficients and delays. Moreover, an example and its numerical simulation are given to illustrate the main results.

  6. New convergence behavior of solutions to Cohen-Grossberg neural networks with delays and time-varying coefficients

    International Nuclear Information System (INIS)

    Liu Bingwen

    2008-01-01

    In this Letter the convergence behavior of Cohen-Grossberg neural networks with delays and time-varying coefficients are considered. Some sufficient conditions are established to ensure that the solutions of the networks converge locally exponentially to zero point, which are new and complement of previously known results

  7. Design of Multijunction Photovoltaic Cells Optimized for Varied Atmospheric Conditions

    Directory of Open Access Journals (Sweden)

    C. Zhang

    2014-01-01

    Full Text Available Band gap engineering provides an opportunity to not only provide higher overall conversion efficiencies of the reference AM1.5 spectra but also customize PV device design for specific geographic locations and microenvironments based on atmospheric conditions characteristic to that particular location. Indium gallium nitride and other PV materials offer the opportunity for limited bandgap engineering to match spectra. The effects of atmospheric conditions such as aerosols, cloud cover, water vapor, and air mass have been shown to cause variations in spectral radiance that alters PV system performance due to both overrating and underrating. Designing PV devices optimized for spectral radiance of a particular region can result in improved PV system performance. This paper presents a new method for designing geographically optimized PV cells with using a numerical model for bandgap optimization. The geographic microclimate spectrally resolved solar flux for twelve representative atmospheric conditions for the incident radiation angle (zenith angle of 48.1° and fixed array angle of 40° is used to iteratively optimize the band gap for tandem, triple, and quad-layer of InGaN-based multijunction cells. The results of this method are illustrated for the case study of solar farms in the New York region and discussed.

  8. Positive Almost Periodic Solutions for a Time-Varying Fishing Model with Delay

    Directory of Open Access Journals (Sweden)

    Xia Li

    2011-01-01

    Full Text Available This paper is concerned with a time-varying fishing model with delay. By means of the continuation theorem of coincidence degree theory, we prove that it has at least one positive almost periodic solution.

  9. Varied overstrain injuries of the vertebral column conditioned by evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kohlbach, W

    1983-08-01

    During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components.

  10. Varied overstrain injuries of the vertebral column conditioned by evolution

    International Nuclear Information System (INIS)

    Kohlbach, W.

    1983-01-01

    During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components. (orig.) [de

  11. Varied overstrain injuries of the vertebral column conditioned by evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kohlbach, W.

    1983-08-01

    During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components.

  12. Weed spectrum and selectivity of tembotrione under varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Gatzweiler, Elmar

    2012-03-01

    Full Text Available Tembotrione is a novel HPPD maize herbicide effective against a wide range of broadleaf and grass weeds. Some characteristics of this compound are described in this paper linking weed and crop responses following tembotrione applications to environmental parameters or use conditions. The activity of HPPD herbicides is very much dependant on the availability of light. Increasing illumination intensities following application augmented the activity levels of several comparable HPPD compounds in a growth chamber experiment. Tembotrione was shown to be more efficacious at low and high illumination intensities compared to standard herbicides applied at the same rate. At the high intensity, tembotrione retained its high efficacy from two up to four weeks after application showing a rapid and strong herbicidal activity. The activity following post-emergent treatments of tembotrione against broadleaf weeds was influenced by soil characteristics such as soil texture and organic matter content in a glasshouse test. The level of weed suppression clearly declined stronger on heavier soils than on lighter soils at a rather low application rate of 12.5 g a.i./ha and lower. This is a clear indication of residual efficacy of tembotrione. The selectivity of tembotrione was tested on numerous maize varieties following post-emergent treatment with tembotrione alone or in mixture with the safener isoxadifen-ethyl under field conditions in Germany in comparison to a standard herbicide. The level of crop phytotoxicity tended to increase in the following order: Tembotrione plus safener, standard herbicide to tembotrione alone. Only the mixture of tembotrione with safener did not cause significant adverse effects on maize. Another field experiment in the USA examined crop phytotoxicity using one maize variety in a situation of infurrow soil insecticide treatment followed by a post-emergent application of tembotrione (plus/minus isoxadifen-ethyl and standard herbicides

  13. An analysis of periodic solutions of bi-directional associative memory networks with time-varying delays

    International Nuclear Information System (INIS)

    Cao Jinde; Jiang Qiuhao

    2004-01-01

    In this Letter, several sufficient conditions are derived for the existence and uniqueness of periodic oscillatory solution for bi-directional associative memory (BAM) networks with time-varying delays by employing a new Lyapunov functional and an elementary inequality, and all other solutions of the BAM networks converge exponentially to the unique periodic solution. These criteria are presented in terms of system parameters and have important leading significance in the design and applications of periodic neural circuits for delayed BAM. As an illustration, two numerical examples are worked out using the results obtained

  14. Solute-solvent cavity and bridge functions. I. Varying size of the solute

    International Nuclear Information System (INIS)

    Vyalov, I.; Chuev, G.; Georgi, N.

    2014-01-01

    In this work we present the results of the extensive molecular simulations of solute-solvent cavity and bridge functions. The mixtures of Lennard-Jones solvent with Lennard-Jones solute at infinite dilution are considered for different solute-solvent size ratios—up to 4:1. The Percus-Yevick and hypernetted chain closures deviate substantially from simulation results in the investigated temperature and density ranges. We also find that the behavior of the indirect and cavity correlation functions is non-monotonous within the hard-core region, but the latter can be successfully approximated by mean-field theory if the solute-solvent interaction energy is divided into repulsive and attractive contribution, according to Weeks-Chandler-Andersen theory. Furthermore, in spite of the non-monotonous behavior of logarithm of the cavity function and the indirect correlation function, their difference, i.e., the bridge function remains constant within the hard-core region. Such behavior of the bridge and indirect correlation functions at small distances and for small values of indirect correlation function is well known from the Duh-Haymet plots, where the non-unique relationship results in loops of the bridge function vs. indirect correlation function graphs. We show that the same pathological behavior appears also when distance is small and indirect correlation function is large. We further show that the unique functional behavior of the bridge function can be established when bridge is represented as a function of the renormalized, repulsive indirect correlation function

  15. Equilibrium and Dynamic Osmotic Behaviour of Aqueous Solutions with Varied Concentration at Constant and Variable Volume

    Science.gov (United States)

    Minkov, Ivan L.; Manev, Emil D.; Sazdanova, Svetla V.; Kolikov, Kiril H.

    2013-01-01

    Osmosis is essential for the living organisms. In biological systems the process usually occurs in confined volumes and may express specific features. The osmotic pressure in aqueous solutions was studied here experimentally as a function of solute concentration (0.05–0.5 M) in two different regimes: of constant and variable solution volume. Sucrose, a biologically active substance, was chosen as a reference solute for the complex tests. A custom made osmotic cell was used. A novel operative experimental approach, employing limited variation of the solution volume, was developed and applied for the purpose. The established equilibrium values of the osmotic pressure are in agreement with the theoretical expectations and do not exhibit any evident differences for both regimes. In contrast, the obtained kinetic dependences reveal striking divergence in the rates of the process at constant and varied solution volume for the respective solute concentrations. The rise of pressure is much faster at constant solution volume, while the solvent influx is many times greater in the regime of variable volume. The results obtained suggest a feasible mechanism for the way in which the living cells rapidly achieve osmotic equilibrium upon changes in the environment. PMID:24459448

  16. A hepatitis C virus infection model with time-varying drug effectiveness: solution and analysis.

    Directory of Open Access Journals (Sweden)

    Jessica M Conway

    2014-08-01

    Full Text Available Simple models of therapy for viral diseases such as hepatitis C virus (HCV or human immunodeficiency virus assume that, once therapy is started, the drug has a constant effectiveness. More realistic models have assumed either that the drug effectiveness depends on the drug concentration or that the effectiveness varies over time. Here a previously introduced varying-effectiveness (VE model is studied mathematically in the context of HCV infection. We show that while the model is linear, it has no closed-form solution due to the time-varying nature of the effectiveness. We then show that the model can be transformed into a Bessel equation and derive an analytic solution in terms of modified Bessel functions, which are defined as infinite series, with time-varying arguments. Fitting the solution to data from HCV infected patients under therapy has yielded values for the parameters in the model. We show that for biologically realistic parameters, the predicted viral decay on therapy is generally biphasic and resembles that predicted by constant-effectiveness (CE models. We introduce a general method for determining the time at which the transition between decay phases occurs based on calculating the point of maximum curvature of the viral decay curve. For the parameter regimes of interest, we also find approximate solutions for the VE model and establish the asymptotic behavior of the system. We show that the rate of second phase decay is determined by the death rate of infected cells multiplied by the maximum effectiveness of therapy, whereas the rate of first phase decline depends on multiple parameters including the rate of increase of drug effectiveness with time.

  17. Solution to the monoenergetic time-dependent neutron transport equation with a time-varying source

    International Nuclear Information System (INIS)

    Ganapol, B.D.

    1986-01-01

    Even though fundamental time-dependent neutron transport problems have existed since the inception of neutron transport theory, it has only been recently that a reliable numerical solution to one of the basic problems has been obtained. Experience in generating numerical solutions to time-dependent transport equations has indicated that the multiple collision formulation is the most versatile numerical technique for model problems. The formulation coupled with a moment reconstruction of each collided flux component has led to benchmark-quality (four- to five-digit accuracy) numerical evaluation of the neutron flux in plane infinite geometry for any degree of scattering anisotropy and for both pulsed isotropic and beam sources. As will be shown in this presentation, this solution can serve as a Green's function, thus extending the previous results to more complicated source situations. Here we will be concerned with a time-varying source at the center of an infinite medium. If accurate, such solutions have both pedagogical and practical uses as benchmarks against which other more approximate solutions designed for a wider class of problems can be compared

  18. Modelling and Control of Ionic Electroactive Polymer Actuators under Varying Humidity Conditions

    Directory of Open Access Journals (Sweden)

    S. Sunjai Nakshatharan

    2018-02-01

    Full Text Available In this work, we address the problem of position control of ionic electroactive polymer soft actuators under varying relative humidity conditions. The impact of humidity on the actuation performance of ionic actuators is studied through frequency response and impedance spectroscopy analysis. Considering the uncertain performance of the actuator under varying humidity conditions, an adaptable model using the neural network method is developed. The model uses relative humidity magnitude as one of the model parameters, making it robust to different environmental conditions. Utilizing the model, a closed-loop controller based on the model predictive controller is developed for position control of the actuator. The developed model and controller are experimentally verified and found to be capable of predicting and controlling the actuators with excellent tracking accuracy under relative humidity conditions varying in the range of 10–90%.

  19. Zhang neural network for online solution of time-varying convex quadratic program subject to time-varying linear-equality constraints

    International Nuclear Information System (INIS)

    Zhang Yunong; Li Zhan

    2009-01-01

    In this Letter, by following Zhang et al.'s method, a recurrent neural network (termed as Zhang neural network, ZNN) is developed and analyzed for solving online the time-varying convex quadratic-programming problem subject to time-varying linear-equality constraints. Different from conventional gradient-based neural networks (GNN), such a ZNN model makes full use of the time-derivative information of time-varying coefficient. The resultant ZNN model is theoretically proved to have global exponential convergence to the time-varying theoretical optimal solution of the investigated time-varying convex quadratic program. Computer-simulation results further substantiate the effectiveness, efficiency and novelty of such ZNN model and method.

  20. Computing Conditional VaR using Time-varying CopulasComputing Conditional VaR using Time-varying Copulas

    Directory of Open Access Journals (Sweden)

    Beatriz Vaz de Melo Mendes

    2005-12-01

    Full Text Available It is now widespread the use of Value-at-Risk (VaR as a canonical measure at risk. Most accurate VaR measures make use of some volatility model such as GARCH-type models. However, the pattern of volatility dynamic of a portfolio follows from the (univariate behavior of the risk assets, as well as from the type and strength of the associations among them. Moreover, the dependence structure among the components may change conditionally t past observations. Some papers have attempted to model this characteristic by assuming a multivariate GARCH model, or by considering the conditional correlation coefficient, or by incorporating some possibility for switches in regimes. In this paper we address this problem using time-varying copulas. Our modeling strategy allows for the margins to follow some FIGARCH type model while the copula dependence structure changes over time.

  1. Bearing Condition Recognition and Degradation Assessment under Varying Running Conditions Using NPE and SOM

    Directory of Open Access Journals (Sweden)

    Shaohui Zhang

    2014-01-01

    Full Text Available Manifold learning methods have been widely used in machine condition monitoring and fault diagnosis. However, the results reported in these studies focus on the machine faults under stable loading and rotational speeds, which cannot interpret the practical machine running. Rotating machine is always running under variable speeds and loading, which makes the vibration signal more complicated. To address such concern, the NPE (neighborhood preserving embedding is applied for bearing fault classification. Compared with other algorithms (PCA, LPP, LDA, and ISOP, the NPE performs well in feature extraction. Since the traditional time domain signal denoising is time consuming and memory consuming, we denoise the signal features directly in feature space. Furthermore, NPE and SOM (self-organizing map are combined to assess the bearing degradation performance. Simulation and experiment results validate the effectiveness of the proposed method.

  2. Conditioning of radioactive waste solutions by cementation

    International Nuclear Information System (INIS)

    Vejmelka, P.; Rudolph, G.; Kluger, W.; Koester, R.

    1992-02-01

    For the cementation of the low and intermediate level evaporator concentrates resulting from the reprocessing of spent fuel numerous experiments were performed to optimize the waste form composition and to characterize the final waste form. Concerning the cementation process, properties of the waste/cement suspension were investigated. These investigations include the dependence of viscosity, bleeding, setting time and hydration heat from the waste cement slurry composition. For the characterization of the waste forms, the mechanical, thermal and chemical stability were determined. For special cases detailed investigations were performed to determine the activity release from waste packages under defined mechanical and thermal stresses. The investigations of the interaction of the waste forms with aqueous solutions include the determination of the Cs/Sr release, the corrosion resistance and the release of actinides. The Cs/Sr release was determined in dependence of the cement type, additives, setting time and sample size. (orig./DG) [de

  3. Towards artificial intelligence based diesel engine performance control under varying operating conditions using support vector regression

    Directory of Open Access Journals (Sweden)

    Naradasu Kumar Ravi

    2013-01-01

    Full Text Available Diesel engine designers are constantly on the look-out for performance enhancement through efficient control of operating parameters. In this paper, the concept of an intelligent engine control system is proposed that seeks to ensure optimized performance under varying operating conditions. The concept is based on arriving at the optimum engine operating parameters to ensure the desired output in terms of efficiency. In addition, a Support Vector Machines based prediction model has been developed to predict the engine performance under varying operating conditions. Experiments were carried out at varying loads, compression ratios and amounts of exhaust gas recirculation using a variable compression ratio diesel engine for data acquisition. It was observed that the SVM model was able to predict the engine performance accurately.

  4. Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

    NARCIS (Netherlands)

    Miotto, Renato Fuzaro; Wolf, William Roberto; De Santana, Leandro Dantas

    2018-01-01

    This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet’s theory and the inverse strip technique. In the

  5. Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

    NARCIS (Netherlands)

    Miotto, Renato Fuzaro; Wolf, William Roberto; De Santana, Leandro Dantas

    This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet’s theory and the inverse strip technique. In the

  6. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions

    Directory of Open Access Journals (Sweden)

    Lang Xue

    2017-06-01

    Full Text Available Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  7. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions.

    Science.gov (United States)

    Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

    2017-06-20

    Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  8. Remaining useful life estimation for deteriorating systems with time-varying operational conditions and condition-specific failure zones

    Directory of Open Access Journals (Sweden)

    Li Qi

    2016-06-01

    Full Text Available Dynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life (RUL for the deteriorating systems. This paper presents a method based on probabilistic and stochastic approaches to estimate system RUL for periodically monitored degradation processes with dynamic time-varying operational conditions and condition-specific failure zones. The method assumes that the degradation rate is influenced by specific operational condition and moreover, the transition between different operational conditions plays the most important role in affecting the degradation process. These operational conditions are assumed to evolve as a discrete-time Markov chain (DTMC. The failure thresholds are also determined by specific operational conditions and described as different failure zones. The 2008 PHM Conference Challenge Data is utilized to illustrate our method, which contains mass sensory signals related to the degradation process of a commercial turbofan engine. The RUL estimation method using the sensor measurements of a single sensor was first developed, and then multiple vital sensors were selected through a particular optimization procedure in order to increase the prediction accuracy. The effectiveness and advantages of the proposed method are presented in a comparison with existing methods for the same dataset.

  9. Globally exponential stability condition of a class of neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Liao, T.-L.; Yan, J.-J.; Cheng, C.-J.; Hwang, C.-C.

    2005-01-01

    In this Letter, the globally exponential stability for a class of neural networks including Hopfield neural networks and cellular neural networks with time-varying delays is investigated. Based on the Lyapunov stability method, a novel and less conservative exponential stability condition is derived. The condition is delay-dependent and easily applied only by checking the Hamiltonian matrix with no eigenvalues on the imaginary axis instead of directly solving an algebraic Riccati equation. Furthermore, the exponential stability degree is more easily assigned than those reported in the literature. Some examples are given to demonstrate validity and excellence of the presented stability condition herein

  10. Attenuation of organic micropollutants in an urban lowland stream under varying seasonal and hydrological conditions

    Science.gov (United States)

    Jaeger, Anna; Posselt, Malte; Schaper, Jonas; Lewandowski, Jörg

    2017-04-01

    Transport and fate of polar organic micropollutants in urban streams are of increasing concern for urban water management. Appropriate river management techniques may support a river's ability to self-purify. The river Erpe, an urban lowland stream located in Berlin, Germany, receives treated wastewater which increases its discharge up to 4-fold. Numerous micropollutants (e.g. pharmaceuticals, personal care products, performance chemicals) which survive the treatment process are released into the river and threaten ecosystems and aquatic groundwater quality. In the present work the transport of 57 substances was investigated along a 4.7 km stretch of the river with the aim of understanding the influence of varying seasonal and hydrological conditions on micropollutant fate. We hypothesized that particularly transient storage is a main driver of micropollutant attenuation. A Lagrangian sampling scheme was applied to follow water parcels down the river using the diurnal fluctuations of conservative solute concentrations as an intrinsic tracer. Water samples were collected at two (April) and three (June) stations along a 4.7 km reach downstream of the wastewater inflow. In June the experiment was conducted twice, before and after the first stretch was cleared of macrophytes. Each experiment comprised of hourly sample collection for 48 hours, accompanied by discharge measurements and continuous data logging of water-level, -temperature and electric conductivity. The set of micropollutants, which included both parent compounds and transformation products, was analysed by a newly developed direct injection-UHPLC-MS/MS method. The behaviour of individual micropollutants was compound-specific. Carbamazepine and benzotriazole were persistent along the river stretch while substances such as valsartan and metoprolol were attenuated by up to 15% of their original concentration. Interestingly, some transformation products, such as valsartan acid increased in concentration

  11. Modelling Conditional and Unconditional Heteroskedasticity with Smoothly Time-Varying Structure

    DEFF Research Database (Denmark)

    Amado, Christina; Teräsvirta, Timo

    multiplier type misspecification tests. Finite-sample properties of these procedures and tests are examined by simulation. An empirical application to daily stock returns and another one to daily exchange rate returns illustrate the functioning and properties of our modelling strategy in practice......In this paper, we propose two parametric alternatives to the standard GARCH model. They allow the conditional variance to have a smooth time-varying structure of either ad- ditive or multiplicative type. The suggested parameterizations describe both nonlinearity and structural change...... in the conditional and unconditional variances where the transition between regimes over time is smooth. A modelling strategy for these new time-varying parameter GARCH models is developed. It relies on a sequence of Lagrange multiplier tests, and the adequacy of the estimated models is investigated by Lagrange...

  12. Effect of Alkaline Solution with Varying Mix Proportion on Geopolymer Mortar

    Science.gov (United States)

    Karuppuchamy, K.; Ananthkumar, M.; Raghavapriya, S. M.

    2018-02-01

    Cement production is attributed by emission of carbon dioxide which causes severe environmental impacts. This has led to the invention of special construction materials which can replace cement. On the other hand, these construction materials (like Fly ash, Metakaolin) also need to be inexpensive and should possess all the characteristics of cementitious materials. In this project, the effect of geopolymerization on the properties of the end product were studied with varying distillation of NaOH solution (10M, 12M and 15M) for different mix proportion (1:1, 1:2 and 1:3). Curing was done for 1 day at a temperature of 60°C and 80°C respectively. The densities, compressive strength, alkalinity, co-efficient of absorption were determined. As a result, the experiments showed the effect of factors such as mix proportion, curing temperature and curing day on the physical and mechanical properties such as mix proportion of the geopolymer concrete. Results of NaOH concentration of 12M concentration cured for 24 hours at 80°C and 60°C showed better mechanical performance than the rest of the concentrations.

  13. Explicit solution for a wave equation with nonlocal condition

    Science.gov (United States)

    Bazhlekova, Emilia; Dimovski, Ivan

    2012-11-01

    An initial-boundary value problem with a nonlocal boundary condition for one-dimensional wave equation is studied. Applying spectral projections, we find a series solution of the problem. The character of the solution found shows that the oscillation amplitude of the system described by this equation increases with time at any fixed x in absence of external forces. To find a representation of the solution more convenient for numerical calculation we develop a two-dimensional operational calculus for the problem. The solution is expressed as a sum of non-classical convolution products of particular solutions and the arbitrary initial functions. This result is an extension of the classical Duhamel principle for the space variable. The representation is used successfully for numerical computation and visualization of the solution. Numerical results obtained for specific test problems with known exact solutions indicate that the present technique provides accurate numerical solutions.

  14. Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Wei Qian

    2013-01-01

    Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

  15. Sex differences in in-group cooperation vary dynamically with competitive conditions and outcomes.

    Science.gov (United States)

    Bailey, Drew H; Winegard, Benjamin; Oxford, Jon; Geary, David C

    2012-03-18

    Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  16. Sex Differences in In-Group Cooperation Vary Dynamically with Competitive Conditions and Outcomes

    Directory of Open Access Journals (Sweden)

    Drew H. Bailey

    2012-01-01

    Full Text Available Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus. In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  17. The effect of varying talker identity and listening conditions on gaze behavior during audiovisual speech perception.

    Science.gov (United States)

    Buchan, Julie N; Paré, Martin; Munhall, Kevin G

    2008-11-25

    During face-to-face conversation the face provides auditory and visual linguistic information, and also conveys information about the identity of the speaker. This study investigated behavioral strategies involved in gathering visual information while watching talking faces. The effects of varying talker identity and varying the intelligibility of speech (by adding acoustic noise) on gaze behavior were measured with an eyetracker. Varying the intelligibility of the speech by adding noise had a noticeable effect on the location and duration of fixations. When noise was present subjects adopted a vantage point that was more centralized on the face by reducing the frequency of the fixations on the eyes and mouth and lengthening the duration of their gaze fixations on the nose and mouth. Varying talker identity resulted in a more modest change in gaze behavior that was modulated by the intelligibility of the speech. Although subjects generally used similar strategies to extract visual information in both talker variability conditions, when noise was absent there were more fixations on the mouth when viewing a different talker every trial as opposed to the same talker every trial. These findings provide a useful baseline for studies examining gaze behavior during audiovisual speech perception and perception of dynamic faces.

  18. Mobile geographic information system (GIS) solution for pavement condition surveys.

    Science.gov (United States)

    2012-06-28

    This report discusses the design and implementation of a software-based solution that will improve the data collection processes during the Pavement Condition Surveys (PCS) conducted by the State Materials Office (SMO) of the Florida Department of Tr...

  19. Solution to random differential equations with boundary conditions

    Directory of Open Access Journals (Sweden)

    Fairouz Tchier

    2017-04-01

    Full Text Available We study a family of random differential equations with boundary conditions. Using a random fixed point theorem, we prove an existence theorem that yields a unique random solution.

  20. Understanding and simulating vibrations of plain bridge cables under varying meteorological conditions

    DEFF Research Database (Denmark)

    Matteoni, Giulia

    amplitude peak to peak amplitudes, occurred. This latter behaviour was likely to be associated to dry inclined galloping. Passive dynamic wind tunnel tests were finally undertaken in presence of rain, using the same cable model as adopted in the dry state. The tests served to improve the current......The dissertation investigates the phenomenon of wind induced vibration of bridge cables under varying meteorological conditions. A twin research approach is adopted, where wind tunnel investigation of full-scale bridge cable section models is paralleled with theoretical modelling. A literature......-scale monitoring, wind tunnel testing and theoretical modelling. An extensive wind tunnel test campaign was then undertaken in order to further understand the onset conditions and characteristics of instability in the different climatic conditions described in the literature. Tests were separated into two...

  1. Differences in displayed pump flow compared to measured flow under varying conditions during simulated cardiopulmonary bypass.

    LENUS (Irish Health Repository)

    Hargrove, M

    2008-07-01

    Errors in blood flow delivery due to shunting have been reported to reduce flow by, potentially, up to 40-83% during cardiopulmonary bypass. The standard roller-pump measures revolutions per minute and a calibration factor for different tubing sizes calculates and displays flow accordingly. We compared displayed roller-pump flow with ultrasonically measured flow to ascertain if measured flow correlated with the heart-lung pump flow reading. Comparison of flows was measured under varying conditions of pump run duration, temperature, viscosity, varying arterial\\/venous loops, occlusiveness, outlet pressure, use of silicone or polyvinyl chloride (PVC) in the roller race, different tubing diameters, and use of a venous vacuum-drainage device.

  2. An in vitro experimental study of flow past aortic valve under varied pulsatile conditions

    Science.gov (United States)

    Zhang, Ruihang; Zhang, Yan

    2017-11-01

    Flow past aortic valve represents a complex fluid-structure interaction phenomenon that involves pulsatile, vortical, and turbulent conditions. The flow characteristics immediately downstream of the valve, such as the variation of pulsatile flow velocity, formation of vortices, distribution of shear stresses, are of particular interest to further elucidate the role of hemodynamics in various aortic diseases. However, the fluid dynamics of a realistic aortic valve is not fully understood. Particularly, it is unclear how the flow fields downstream of the aortic valve would change under varied pulsatile inlet boundary conditions. In this study, an in vitro experiment has been conducted to investigate the flow fields downstream of a silicone aortic valve model within a cardiovascular flow simulator. Phased-locked Particle Image Velocimetry measurements were performed to map the velocity fields and Reynolds normal and shear stresses at different phases in a cardiac cycle. Temporal variations of pressure across the valve model were measured using high frequency transducers. Results have been compared for different pulsatile inlet conditions, including varied frequencies (heart rates), magnitudes (stroke volumes), and cardiac contractile functions (shapes of waveforms).

  3. Applicability of common stomatal conductance models in maize under varying soil moisture conditions.

    Science.gov (United States)

    Wang, Qiuling; He, Qijin; Zhou, Guangsheng

    2018-07-01

    In the context of climate warming, the varying soil moisture caused by precipitation pattern change will affect the applicability of stomatal conductance models, thereby affecting the simulation accuracy of carbon-nitrogen-water cycles in ecosystems. We studied the applicability of four common stomatal conductance models including Jarvis, Ball-Woodrow-Berry (BWB), Ball-Berry-Leuning (BBL) and unified stomatal optimization (USO) models based on summer maize leaf gas exchange data from a soil moisture consecutive decrease manipulation experiment. The results showed that the USO model performed best, followed by the BBL model, BWB model, and the Jarvis model performed worst under varying soil moisture conditions. The effects of soil moisture made a difference in the relative performance among the models. By introducing a water response function, the performance of the Jarvis, BWB, and USO models improved, which decreased the normalized root mean square error (NRMSE) by 15.7%, 16.6% and 3.9%, respectively; however, the performance of the BBL model was negative, which increased the NRMSE by 5.3%. It was observed that the models of Jarvis, BWB, BBL and USO were applicable within different ranges of soil relative water content (i.e., 55%-65%, 56%-67%, 37%-79% and 37%-95%, respectively) based on the 95% confidence limits. Moreover, introducing a water response function, the applicability of the Jarvis and BWB models improved. The USO model performed best with or without introducing the water response function and was applicable under varying soil moisture conditions. Our results provide a basis for selecting appropriate stomatal conductance models under drought conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Modelling of the diffusion of pollutants in the atmosphere under varying conditions in large cultivated regions

    International Nuclear Information System (INIS)

    Wueneke, C.D.; Schultz, H.

    1975-01-01

    The most important routines of a numerical code based on the particle-in-cell-method for calculating the transport and the turbulent dispersion of inert and radio-active pollutants in the atmosphere have been programmed and have been tested successfully on the CDC computer CYBER 73/76 of the Regional Computer Centre for Niedersachsen in Hanover. Compared to the Gaussian plume model such a numerical code based on the particle-in-cell-method offers several advantages for the computation of the diffusion under varying conditions in large cultivated regions. (orig.) [de

  5. Positive and negative variations in capacitive images for given defects under varying experimental conditions

    Science.gov (United States)

    Li, Chen; Yin, Xiaokang; Li, Zhen; Li, Wei; Chen, Guoming

    2018-04-01

    Capacitive imaging (CI) technique is a novel electromagnetic NDE technique. The Quasi-static electromagnetic field from the carefully designed electrode pair will vary when the electrical properties of the sample change, leading to the possibility of imaging. It is observed that for a given specimen, the targeted features appear as different variations in capacitive images under different experimental conditions. In some cases, even opposite variations occur, which brings confusion to indication interpretation. It is thus thought interesting to embark on investigations into the cause and effects of the negative variation phenomenon. In this work, the positive and negative variations were first explained from the measurement sensitivity distribution perspective. This was then followed by a detailed analysis using finite element models in COMSOL. A parametric experimental study on a glass fiber composite plate with artificial defects was then carried out to investigate how the experimental conditions affect the variation.

  6. Periodic solutions of asymptotically linear Hamiltonian systems without twist conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Rong [Coll. of Mathematics and Physics, Nanjing Univ. of Information Science and Tech., Nanjing (China); Dept. of Mathematics, Southeast Univ., Nanjing (China); Zhang Dongfeng [Dept. of Mathematics, Southeast Univ., Nanjing (China)

    2010-05-15

    In dynamical system theory, especially in many fields of applications from mechanics, Hamiltonian systems play an important role, since many related equations in mechanics can be written in an Hamiltonian form. In this paper, we study the existence of periodic solutions for a class of Hamiltonian systems. By applying the Galerkin approximation method together with a result of critical point theory, we establish the existence of periodic solutions of asymptotically linear Hamiltonian systems without twist conditions. Twist conditions play crucial roles in the study of periodic solutions for asymptotically linear Hamiltonian systems. The lack of twist conditions brings some difficulty to the study. To the authors' knowledge, very little is known about the case, where twist conditions do not hold. (orig.)

  7. Assessment of a surface-layer parameterization scheme in an atmospheric model for varying meteorological conditions

    Directory of Open Access Journals (Sweden)

    T. J. Anurose

    2014-06-01

    Full Text Available The performance of a surface-layer parameterization scheme in a high-resolution regional model (HRM is carried out by comparing the model-simulated sensible heat flux (H with the concurrent in situ measurements recorded at Thiruvananthapuram (8.5° N, 76.9° E, a coastal station in India. With a view to examining the role of atmospheric stability in conjunction with the roughness lengths in the determination of heat exchange coefficient (CH and H for varying meteorological conditions, the model simulations are repeated by assigning different values to the ratio of momentum and thermal roughness lengths (i.e. z0m/z0h in three distinct configurations of the surface-layer scheme designed for the present study. These three configurations resulted in differential behaviour for the varying meteorological conditions, which is attributed to the sensitivity of CH to the bulk Richardson number (RiB under extremely unstable, near-neutral and stable stratification of the atmosphere.

  8. Analysis of grain filling process to the varied meteorological conditions in winter wheat [Triticum aestivum] cultivars

    International Nuclear Information System (INIS)

    Inoue, K.; Nakazono, K.; Wakiyama, Y.

    2005-01-01

    This paper describes effects of varied meteorological conditions on the grain filling periods, stabilities of yield and quality of winter wheat cultivars with different maturity characteristics (cv. Ayahikari, Norin61, Bandowase, and Tsurupikari). In the field experiments, the meteorological treatments were made during the first heading time on 17 April 2001 and the middle heading time on 24 April 2000. Air temperature, global solar radiation and soil moisture were controlled using a rain shelter, cheesecloth and irrigation system. The growth speed and growth period of wheat grains varied among four winter wheat cultivars, depending on meteorological conditions. The growth speed increased within 1 8.4 deg C of mean air temperature over the 30 days after the anthesis. On the other hand, it was found that the growth speed of wheat grains and the maximum number of wheat grains (Ymax) decreased greatly with the 44.4% interception of global solar radiation. Logistic functions were fitted to the relationship between the relative thousand-kernel-weight (Y/Ymax) and the total integrated temperature (sigmaTa) after heading for all treatment conditions. The maximum weight of grains (Ymax) achieved at the harvest time varied somewhat clearly among four winter wheat cultivars and meteorological conditions. Multiple regression analysis showed that the grain yield (Ymax) of four wheat cultivars correlated positively with daily mean solar radiation. It was also found that the cultivar Ayahikari had a highly significant negative correlation between its grain weight and soil moisture. Namely, the grain weight of high soil moisture plot with pF=1.5 was lower by about 9% than that of a control plot with pF=3.5. On the other hand, the grain yield of cultivar Norin61 responded inversely to a wet environment, indicating that its grain weight was higher for high soil moisture and high wet-bulb temperature than for a dry environment. The grain yield of early varieties of Bandowase and

  9. Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions.

    Science.gov (United States)

    Henkel, Sebastian G; Ter Beek, Alexander; Steinsiek, Sonja; Stagge, Stefan; Bettenbrock, Katja; de Mattos, M Joost Teixeira; Sauter, Thomas; Sawodny, Oliver; Ederer, Michael

    2014-01-01

    For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear how they interplay in the regulation of ETC enzymes under micro-aerobic chemostat conditions. Also, there are diverse results which and how quinones (oxidised/reduced, ubiquinone/other quinones) are controlling the ArcBA two-component system. In the following a mathematical model of the E. coli ETC linked to basic modules for substrate uptake, fermentation product excretion and biomass formation is introduced. The kinetic modelling focusses on regulatory principles of the ETC for varying oxygen conditions in glucose-limited continuous cultures. The model is based on the balance of electron donation (glucose) and acceptance (oxygen or other acceptors). Also, it is able to account for different chemostat conditions due to changed substrate concentrations and dilution rates. The parameter identification process is divided into an estimation and a validation step based on previously published and new experimental data. The model shows that experimentally observed, qualitatively different behaviour of the ubiquinone redox state and the ArcA activity profile in the micro-aerobic range for different experimental conditions can emerge from a single network structure. The network structure features a strong feed-forward effect from the FNR regulatory system to the ArcBA regulatory system via a common control of the dehydrogenases of the ETC. The model supports the hypothesis that ubiquinone but not ubiquinol plays a key role in determining the activity of ArcBA in a glucose-limited chemostat at micro-aerobic conditions.

  10. Buckling of Nonprismatic Column on Varying Elastic Foundation with Arbitrary Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Ahmad A. Ghadban

    2017-01-01

    Full Text Available Buckling of nonprismatic single columns with arbitrary boundary conditions resting on a nonuniform elastic foundation may be considered as the most generalized treatment of the subject. The buckling differential equation for such columns is extremely difficult to solve analytically. Thus, the authors propose a numerical approach by discretizing the column into a finite number of segments. Each segment has constants E (modulus of elasticity, I (moment of inertia, and β (subgrade stiffness. Next, an exact analytical solution is derived for each prismatic segment resting on uniform elastic foundation. These segments are then assembled in a matrix from which the critical buckling load is obtained. The derived formulation accounts for different end boundary conditions. Validation is performed by benchmarking the present results against analytical solutions found in the literature, showing excellent agreement. After validation, more examples are solved to illustrate the power and flexibility of the proposed method. Overall, the proposed method provides reasonable results, and the examples solved demonstrate the versatility of the developed approach and some of its many possible applications.

  11. Mapping and simulating systematics due to spatially varying observing conditions in DES science verification data

    International Nuclear Information System (INIS)

    Leistedt, B.; Peiris, H. V.; Elsner, F.; Benoit-Lévy, A.; Amara, A.

    2016-01-01

    Spatially varying depth and the characteristics of observing conditions, such as seeing, airmass, or sky background, are major sources of systematic uncertainties in modern galaxy survey analyses, particularly in deep multi-epoch surveys. We present a framework to extract and project these sources of systematics onto the sky, and apply it to the Dark Energy Survey (DES) to map the observing conditions of the Science Verification (SV) data. The resulting distributions and maps of sources of systematics are used in several analyses of DES–SV to perform detailed null tests with the data, and also to incorporate systematics in survey simulations. We illustrate the complementary nature of these two approaches by comparing the SV data with BCC-UFig, a synthetic sky catalog generated by forward-modeling of the DES–SV images. We analyze the BCC-UFig simulation to construct galaxy samples mimicking those used in SV galaxy clustering studies. We show that the spatially varying survey depth imprinted in the observed galaxy densities and the redshift distributions of the SV data are successfully reproduced by the simulation and are well-captured by the maps of observing conditions. The combined use of the maps, the SV data, and the BCC-UFig simulation allows us to quantify the impact of spatial systematics on N(z), the redshift distributions inferred using photometric redshifts. We conclude that spatial systematics in the SV data are mainly due to seeing fluctuations and are under control in current clustering and weak-lensing analyses. However, they will need to be carefully characterized in upcoming phases of DES in order to avoid biasing the inferred cosmological results. Finally, the framework presented here is relevant to all multi-epoch surveys and will be essential for exploiting future surveys such as the Large Synoptic Survey Telescope, which will require detailed null tests and realistic end-to-end image simulations to correctly interpret the deep, high

  12. Detection and classification of alarm threshold violations in condition monitoring systems working in highly varying operational conditions

    Science.gov (United States)

    Strączkiewicz, M.; Barszcz, T.; Jabłoński, A.

    2015-07-01

    All commonly used condition monitoring systems (CMS) enable defining alarm thresholds that enhance efficient surveillance and maintenance of dynamic state of machinery. The thresholds are imposed on the measured values such as vibration-based indicators, temperature, pressure, etc. For complex machinery such as wind turbine (WT) the total number of thresholds might be counted in hundreds multiplied by the number of operational states. All the parameters vary not only due to possible machinery malfunctions, but also due to changes in operating conditions and these changes are typically much stronger than the former ones. Very often, such a behavior may lead to hundreds of false alarms. Therefore, authors propose a novel approach based on parameterized description of the threshold violation. For this purpose the novelty and severity factors are introduced. The first parameter refers to the time of violation occurrence while the second one describes the impact of the indicator-increase to the entire machine. Such approach increases reliability of the CMS by providing the operator with the most useful information of the system events. The idea of the procedure is presented on a simulated data similar to those from a wind turbine.

  13. Detection and classification of alarm threshold violations in condition monitoring systems working in highly varying operational conditions

    International Nuclear Information System (INIS)

    Strączkiewicz, M; Barszcz, T; Jabłoński, A

    2015-01-01

    All commonly used condition monitoring systems (CMS) enable defining alarm thresholds that enhance efficient surveillance and maintenance of dynamic state of machinery. The thresholds are imposed on the measured values such as vibration-based indicators, temperature, pressure, etc. For complex machinery such as wind turbine (WT) the total number of thresholds might be counted in hundreds multiplied by the number of operational states. All the parameters vary not only due to possible machinery malfunctions, but also due to changes in operating conditions and these changes are typically much stronger than the former ones. Very often, such a behavior may lead to hundreds of false alarms. Therefore, authors propose a novel approach based on parameterized description of the threshold violation. For this purpose the novelty and severity factors are introduced. The first parameter refers to the time of violation occurrence while the second one describes the impact of the indicator-increase to the entire machine. Such approach increases reliability of the CMS by providing the operator with the most useful information of the system events. The idea of the procedure is presented on a simulated data similar to those from a wind turbine. (paper)

  14. Risky behavior and its effect on survival: snowshoe hare behavior under varying moonlight conditions

    Science.gov (United States)

    Gigliotti, Laura C.; Diefenbach, Duane R.

    2018-01-01

    Predation and predation risk can exert strong influences on the behavior of prey species. However, risk avoidance behaviors may vary among populations of the same species. We studied a population of snowshoe hares (Lepus americanus) near the southern edge of their range, in Pennsylvania. This population occupies different habitat types, experiences different environmental conditions, and are exposed to different predator species and densities than northern hare populations; therefore, they might exhibit differences in risk avoidance behaviors. We analyzed hare survival, movement rates, and habitat use under different levels of predation risk, as indexed by moonlight. Similar to previous work, we found snowshoe hare survival decreased with increased moon illumination during the winter, but we found differences in behavioral responses to increased predation risk. We found that snowshoe hares did not reduce movement rates during high‐risk nights, but instead found that hares selected areas with denser canopy cover, compared to low‐risk nights. We suggest that behavioral plasticity in response to predation risk allows populations of the same species to respond to localized conditions.

  15. PERT: A Method for Expression Deconvolution of Human Blood Samples from Varied Microenvironmental and Developmental Conditions

    Science.gov (United States)

    Csaszar, Elizabeth; Yu, Mei; Morris, Quaid; Zandstra, Peter W.

    2012-01-01

    The cellular composition of heterogeneous samples can be predicted using an expression deconvolution algorithm to decompose their gene expression profiles based on pre-defined, reference gene expression profiles of the constituent populations in these samples. However, the expression profiles of the actual constituent populations are often perturbed from those of the reference profiles due to gene expression changes in cells associated with microenvironmental or developmental effects. Existing deconvolution algorithms do not account for these changes and give incorrect results when benchmarked against those measured by well-established flow cytometry, even after batch correction was applied. We introduce PERT, a new probabilistic expression deconvolution method that detects and accounts for a shared, multiplicative perturbation in the reference profiles when performing expression deconvolution. We applied PERT and three other state-of-the-art expression deconvolution methods to predict cell frequencies within heterogeneous human blood samples that were collected under several conditions (uncultured mono-nucleated and lineage-depleted cells, and culture-derived lineage-depleted cells). Only PERT's predicted proportions of the constituent populations matched those assigned by flow cytometry. Genes associated with cell cycle processes were highly enriched among those with the largest predicted expression changes between the cultured and uncultured conditions. We anticipate that PERT will be widely applicable to expression deconvolution strategies that use profiles from reference populations that vary from the corresponding constituent populations in cellular state but not cellular phenotypic identity. PMID:23284283

  16. Assessing the effects of adaptation measures on optimal water resources allocation under varied water availability conditions

    Science.gov (United States)

    Liu, Dedi; Guo, Shenglian; Shao, Quanxi; Liu, Pan; Xiong, Lihua; Wang, Le; Hong, Xingjun; Xu, Yao; Wang, Zhaoli

    2018-01-01

    Human activities and climate change have altered the spatial and temporal distribution of water availability which is a principal prerequisite for allocation of different water resources. In order to quantify the impacts of climate change and human activities on water availability and optimal allocation of water resources, hydrological models and optimal water resource allocation models should be integrated. Given that increasing human water demand and varying water availability conditions necessitate adaptation measures, we propose a framework to assess the effects of these measures on optimal allocation of water resources. The proposed model and framework were applied to a case study of the middle and lower reaches of the Hanjiang River Basin in China. Two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP4.5) were employed to project future climate, and the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the variability of flows under historical (1956-2011) and future (2012-2099) conditions. The water availability determined by simulating flow with the VIC hydrological model was used to establish the optimal water resources allocation model. The allocation results were derived under an extremely dry year (with an annual average water flow frequency of 95%), a very dry year (with an annual average water flow frequency of 90%), a dry year (with an annual average water flow frequency of 75%), and a normal year (with an annual average water flow frequency of 50%) during historical and future periods. The results show that the total available water resources in the study area and the inflow of the Danjiangkou Reservoir will increase in the future. However, the uneven distribution of water availability will cause water shortage problems, especially in the boundary areas. The effects of adaptation measures, including water saving, and dynamic control of flood limiting water levels (FLWLs) for reservoir operation, were

  17. Impacts of operating conditions and solution chemistry on osmotic membrane structure and performance

    KAUST Repository

    Wong, Mavis C.Y.; Martinez, Kristina; Ramon, Guy Z.; Hoek, Eric M.V.

    2012-01-01

    Herein, we report on changes in the performance of a commercial cellulose triacetate (CTA) membrane, imparted by varied operating conditions and solution chemistries. Changes to feed and draw solution flow rate did not significantly alter the CTA membrane's water permeability, salt permeability, or membrane structural parameter when operated with the membrane skin layer facing the draw solution (PRO-mode). However, water and salt permeability increased with increasing feed or draw solution temperature, while the membrane structural parameter decreased with increasing draw solution, possibly due to changes in polymer intermolecular interactions. High ionic strength draw solutions may de-swell the CTA membrane via charge neutralization, which resulted in lower water permeability, higher salt permeability, and lower structural parameter. This observed trend was further exacerbated by the presence of divalent cations which tends to swell the polymer to a greater extent. Finally, the calculated CTA membrane's structural parameter was lower and less sensitive to external factors when operated in PRO-mode, but highly sensitive to the same factors when the skin layer faced the feed solution (FO-mode), presumably due to swelling/de-swelling of the saturated porous substructure by the draw solution. This is a first attempt aimed at systematically evaluating the changes in performance of the CTA membrane due to operating conditions and solution chemistry, shedding new insight into the possible advantages and disadvantages of this material in certain applications. © 2011 Elsevier B.V.

  18. Impacts of operating conditions and solution chemistry on osmotic membrane structure and performance

    KAUST Repository

    Wong, Mavis C.Y.

    2012-02-01

    Herein, we report on changes in the performance of a commercial cellulose triacetate (CTA) membrane, imparted by varied operating conditions and solution chemistries. Changes to feed and draw solution flow rate did not significantly alter the CTA membrane\\'s water permeability, salt permeability, or membrane structural parameter when operated with the membrane skin layer facing the draw solution (PRO-mode). However, water and salt permeability increased with increasing feed or draw solution temperature, while the membrane structural parameter decreased with increasing draw solution, possibly due to changes in polymer intermolecular interactions. High ionic strength draw solutions may de-swell the CTA membrane via charge neutralization, which resulted in lower water permeability, higher salt permeability, and lower structural parameter. This observed trend was further exacerbated by the presence of divalent cations which tends to swell the polymer to a greater extent. Finally, the calculated CTA membrane\\'s structural parameter was lower and less sensitive to external factors when operated in PRO-mode, but highly sensitive to the same factors when the skin layer faced the feed solution (FO-mode), presumably due to swelling/de-swelling of the saturated porous substructure by the draw solution. This is a first attempt aimed at systematically evaluating the changes in performance of the CTA membrane due to operating conditions and solution chemistry, shedding new insight into the possible advantages and disadvantages of this material in certain applications. © 2011 Elsevier B.V.

  19. Aerodynamic performance of a vibrating piezoelectric fan under varied operational conditions

    International Nuclear Information System (INIS)

    Stafford, J; Jeffers, N

    2014-01-01

    This paper experimentally examines the bulk aerodynamic performance of a vibrating fan operating in the first mode of vibration. The influence of operating condition on the local velocity field has also been investigated to understand the flow distribution at the exit region and determine the stalling condition for vibrating fans. Fan motion has been generated and controlled using a piezoelectric ceramic attached to a stainless steel cantilever. The frequency and amplitude at resonance were 109.4 Hz and 12.5 mm, respectively. A test facility has been developed to measure the pressure-flow characteristics of the vibrating fan and simultaneously conduct local velocity field measurements using particle image velocimetry. The results demonstrate the impact of system characteristics on the local velocity field. High momentum regions generated due to the oscillating motion exist with a component direction that is tangent to the blade at maximum displacement. These high velocity zones are significantly affected by increasing impedance while flow reversal is a dominant feature at maximum pressure rise. The findings outlined provide useful information for design of thermal management solutions that may incorporate this air cooling approach.

  20. Existence and global exponential stability of periodic solution of memristor-based BAM neural networks with time-varying delays.

    Science.gov (United States)

    Li, Hongfei; Jiang, Haijun; Hu, Cheng

    2016-03-01

    In this paper, we investigate a class of memristor-based BAM neural networks with time-varying delays. Under the framework of Filippov solutions, boundedness and ultimate boundedness of solutions of memristor-based BAM neural networks are guaranteed by Chain rule and inequalities technique. Moreover, a new method involving Yoshizawa-like theorem is favorably employed to acquire the existence of periodic solution. By applying the theory of set-valued maps and functional differential inclusions, an available Lyapunov functional and some new testable algebraic criteria are derived for ensuring the uniqueness and global exponential stability of periodic solution of memristor-based BAM neural networks. The obtained results expand and complement some previous work on memristor-based BAM neural networks. Finally, a numerical example is provided to show the applicability and effectiveness of our theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. A new equilibrium torus solution and GRMHD initial conditions

    Science.gov (United States)

    Penna, Robert F.; Kulkarni, Akshay; Narayan, Ramesh

    2013-11-01

    Context. General relativistic magnetohydrodynamic (GRMHD) simulations are providing influential models for black hole spin measurements, gamma ray bursts, and supermassive black hole feedback. Many of these simulations use the same initial condition: a rotating torus of fluid in hydrostatic equilibrium. A persistent concern is that simulation results sometimes depend on arbitrary features of the initial torus. For example, the Bernoulli parameter (which is related to outflows), appears to be controlled by the Bernoulli parameter of the initial torus. Aims: In this paper, we give a new equilibrium torus solution and describe two applications for the future. First, it can be used as a more physical initial condition for GRMHD simulations than earlier torus solutions. Second, it can be used in conjunction with earlier torus solutions to isolate the simulation results that depend on initial conditions. Methods: We assume axisymmetry, an ideal gas equation of state, constant entropy, and ignore self-gravity. We fix an angular momentum distribution and solve the relativistic Euler equations in the Kerr metric. Results: The Bernoulli parameter, rotation rate, and geometrical thickness of the torus can be adjusted independently. Our torus tends to be more bound and have a larger radial extent than earlier torus solutions. Conclusions: While this paper was in preparation, several GRMHD simulations appeared based on our equilibrium torus. We believe it will continue to provide a more realistic starting point for future simulations.

  2. Genome-wide transcriptome analysis of soybean primary root under varying water-deficit conditions.

    Science.gov (United States)

    Song, Li; Prince, Silvas; Valliyodan, Babu; Joshi, Trupti; Maldonado dos Santos, Joao V; Wang, Jiaojiao; Lin, Li; Wan, Jinrong; Wang, Yongqin; Xu, Dong; Nguyen, Henry T

    2016-01-15

    Soybean is a major crop that provides an important source of protein and oil to humans and animals, but its production can be dramatically decreased by the occurrence of drought stress. Soybeans can survive drought stress if there is a robust and deep root system at the early vegetative growth stage. However, little is known about the genome-wide molecular mechanisms contributing to soybean root system architecture. This study was performed to gain knowledge on transcriptome changes and related molecular mechanisms contributing to soybean root development under water limited conditions. The soybean Williams 82 genotype was subjected to very mild stress (VMS), mild stress (MS) and severe stress (SS) conditions, as well as recovery from the severe stress after re-watering (SR). In total, 6,609 genes in the roots showed differential expression patterns in response to different water-deficit stress levels. Genes involved in hormone (Auxin/Ethylene), carbohydrate, and cell wall-related metabolism (XTH/lipid/flavonoids/lignin) pathways were differentially regulated in the soybean root system. Several transcription factors (TFs) regulating root growth and responses under varying water-deficit conditions were identified and the expression patterns of six TFs were found to be common across the stress levels. Further analysis on the whole plant level led to the finding of tissue-specific or water-deficit levels specific regulation of transcription factors. Analysis of the over-represented motif of different gene groups revealed several new cis-elements associated with different levels of water deficit. The expression patterns of 18 genes were confirmed byquantitative reverse transcription polymerase chain reaction method and demonstrated the accuracy and effectiveness of RNA-Seq. The primary root specific transcriptome in soybean can enable a better understanding of the root response to water deficit conditions. The genes detected in root tissues that were associated with

  3. A solution to the varying response of the linear power monitor induced by xenon poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Godsey, T A; Randall, J D [Texas A and M University (United States)

    1974-07-01

    After conversion to FLIP fuel at Texas A and M, the fuel temperatures were examined very carefully. It was observed that the fuel temperature at 1 Mw varied over a wide range during the week. This variation was shown to be due to the variation in response of the linear CIC which was used to establish reactor power level. A modification of the linear power monitor was designed and installed. The response of this system was verified by using cobalt wires, fuel temperature, and a fission chamber located at 6 feet from the reactor core. The system has proven to be operationally satisfactory. (author)

  4. Phytoremdiation Species And Their Modification Under By Weed Varying Climatic Condition A Changing Scenario

    Directory of Open Access Journals (Sweden)

    Anita Singh

    2015-08-01

    Full Text Available Abstract The major reasons for environmental contamination are population explosion increase in industrial and other urban activities. One of the consequent effect of these activities is heavy metal pollution. It is one of the serious issue to be discussed by the scientists and academicians that how to solve this problem to protect the environment. As heavy metals are non-biodegradable so they require effective cleanup technology. Most of the traditional methods such as excavation solidification and burial are very costly or they simply involve the isolation of the metals from contaminated sites. Among different technologies phytoremediation is best approach for removing metal contamination from environment. It involves plants to remove detoxify or immobilize metals from environment. Weed plants are found to be play very important role in metal remediation. They get affected by climatic variation which is also a consequent effect of environmental pollution. The physiology of plants as well as physiochemical properties of soil gets affected by varying climatic condition. Therefore the present review gives the information on metal remediation processes and how these process particularly phytoremediation by weed plants get affected by climatic changes.

  5. Asymmetric Vibration of Polar Orthotropic Annular Circular Plates of Quadratically Varying Thickness with Same Boundary Conditions

    Directory of Open Access Journals (Sweden)

    N. Bhardwaj

    2008-01-01

    Full Text Available In the present paper, asymmetric vibration of polar orthotropic annular circular plates of quadratically varying thickness resting on Winkler elastic foundation is studied by using boundary characteristic orthonormal polynomials in Rayleigh-Ritz method. Convergence of the results is tested and comparison is made with results already available in the existing literature. Numerical results for the first ten frequencies for various values of parameters describing width of annular plate, thickness profile, material orthotropy and foundation constant for all three possible combinations of clamped, simply supported and free edge conditions are shown and discussed. It is found that (a higher elastic property in circumferential direction leads to higher stiffness against lateral vibration; (b Lateral vibration characteristics of F-Fplates is more sensitive towards parametric changes in material orthotropy and foundation stiffness than C-C and S-Splates; (c Effect of quadratical thickness variation on fundamental frequency is more significant in cases of C-C and S-S plates than that of F-Fplates. Thickness profile which is convex relative to plate center-line tends to result in higher stiffness of annular plates against lateral vibration than the one which is concave and (d Fundamental mode of vibration of C-C and S-Splates is axisymmetrical while that of F-Fplates is asymmetrical.

  6. Antiperiodic Solutions for a Kind of Nonlinear Duffing Equations with a Deviating Argument and Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Changjin Xu

    2014-01-01

    Full Text Available This paper deals with a kind of nonlinear Duffing equation with a deviating argument and time-varying delay. By using differential inequality techniques, some very verifiable criteria on the existence and exponential stability of antiperiodic solutions for the equation are obtained. Our results are new and complementary to previously known results. An example is given to illustrate the feasibility and effectiveness of our main results.

  7. 15N NMR spectroscopic investigation of nitrous and nitric acids in sulfuric acid solutions of varying acidities

    International Nuclear Information System (INIS)

    Prakash, G.K.S.; Heiliger, L.; Olah, G.A.

    1990-01-01

    Both nitrous and nitric acids were studied in sulfuric acid solutions of varying acid strengths by 15 N NMR spectroscopy. The study gives new insights into the nature of intermediates present at different acid strengths. Furthermore, we have also discovered a novel redox reaction between NO 2 + and NO + ions involving the intermediacy of their respective acids. A mechanism is proposed to explain the observed results. 13 refs., 2 figs., 1 tab

  8. Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality.

    Directory of Open Access Journals (Sweden)

    Martin M Gossner

    Full Text Available There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic. We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when

  9. The influence of spatially and temporally varying oceanographic conditions on meroplanktonic metapopulations

    Science.gov (United States)

    Botsford, L. W.; Moloney, C. L.; Hastings, A.; Largier, J. L.; Powell, T. M.; Higgins, K.; Quinn, J. F.

    We synthesize the results of several modelling studies that address the influence of variability in larval transport and survival on the dynamics of marine metapopulations distributed along a coast. Two important benthic invertebrates in the California Current System (CCS), the Dungeness crab and the red sea urchin, are used as examples of the way in which physical oceanographic conditions can influence stability, synchrony and persistence of meroplanktonic metapopulations. We first explore population dynamics of subpopulations and metapopulations. Even without environmental forcing, isolated local subpopulations with density-dependence can vary on time scales roughly twice the generation time at high adult survival, shifting to annual time scales at low survivals. The high frequency behavior is not seen in models of the Dungeness crab, because of their high adult survival rates. Metapopulations with density-dependent recruitment and deterministic larval dispersal fluctuate in an asynchronous fashion. Along the coast, abundance varies on spatial scales which increase with dispersal distance. Coastwide, synchronous, random environmental variability tends to synchronize these metapopulations. Climate change could cause a long-term increase or decrease in mean larval survival, which in this model leads to greater synchrony or extinction respectively. Spatially managed metapopulations of red sea urchins go extinct when distances between harvest refugia become greater than the scale of larval dispersal. All assessments of population dynamics indicate that metapopulation behavior in general dependes critically on the temporal and spatial nature of larval dispersal, which is largely determined by physical oceanographic conditions. We therfore explore physical influences on larval dispersal patterns. Observed trends in temperature and salinity applied to laboratory-determined responses indicate that natural variability in temperature and salinity can lead to variability in

  10. Effect of Varying Acid Hydrolysis Condition in Gracilaria Sp. Fermentation Using Sasad

    Science.gov (United States)

    Mansuit, H.; Samsuri, M. D. C.; Sipaut, C. S.; Yee, C. F.; Yasir, S. M.; Mansa, R.

    2015-04-01

    Macroalgae or seaweed is being considered as promising feedstock for bioalcohol production due to high polysaccharides content. Polysaccharides can be converted into fermentable sugar through acid hydrolysis pre-treatment. In this study, the potential of using carbohydrate-rich macroalgae, Gracilaria sp. as feedstock for bioalcohol production via various acid hydrolysis conditions prior to the fermentation process was investigated and evaluated. The seaweed used in this research was from the red algae group, using species of Gracilaria sp. which was collected from Sg. Petani Kedah, Malaysia. Pre-treatment of substrate was done using H2SO4 and HCl with molarity ranging from 0.2M to 0.8M. The pretreatment time were varied in the range of 15 to 30 minutes. Fermentation was conducted using Sasad, a local Sabahan fermentation agent as a starter culture. Alcohol extraction was done using a distillation unit. Reducing sugar analysis was done by Benedict test method. Alcohol content analysis was done using specific gravity test. After hydrolysis, it was found out that acid hydrolysis at 0.2M H2SO4 and pre-treated for 20 minutes at 121°C has shown the highest reducing sugar content which has yield (10.06 mg/g) of reducing sugar. It was followed by other samples hydrolysis using 0.4M HCl with 30 minutes pre-treatment and 0.2M H2SO4, 15 minutes pre-treatment with yield of 8.06 mg/g and 5.75 mg/g reducing sugar content respectively. In conclusion, acid hydrolysis of Gracilaria sp. can produce higher reducing sugar yield and thus it can further enhance the bioalcohol production yield. Hence, acid hydrolysis of Gracilaria sp. should be studied more as it is an important step in the bioalcohol production and upscaling process.

  11. Multi-Fibre Optode Microsensors: affordable designs for monitoring oxygen in soils under varying environmental conditions

    Science.gov (United States)

    Rezanezhad, F.; Milojevic, T.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2017-12-01

    , where the imaged data is transmitted remotely using a photo-logging system. The MuFO sensor is currently being tested at a Southern Ontario field site in a year-long experiment. Here we present the field and laboratory results of soil O2 monitoring by this newly developed MuFO microsensor system under varying environmental conditions.

  12. IR radiation characteristics of rocket exhaust plumes under varying motor operating conditions

    Directory of Open Access Journals (Sweden)

    Qinglin NIU

    2017-06-01

    Full Text Available The infrared (IR irradiance signature from rocket motor exhaust plumes is closely related to motor type, propellant composition, burn time, rocket geometry, chamber parameters and flight conditions. In this paper, an infrared signature analysis tool (IRSAT was developed to understand the spectral characteristics of exhaust plumes in detail. Through a finite volume technique, flow field properties were obtained through the solution of axisymmetric Navier-Stokes equations with the Reynolds-averaged approach. A refined 13-species, 30-reaction chemistry scheme was used for combustion effects and a k-ε-Rt turbulence model for entrainment effects. Using flowfield properties as input data, the spectrum was integrated with a line of sight (LOS method based on a single line group (SLG model with Curtis-Godson approximation. The model correctly predicted spectral distribution in the wavelengths of 1.50–5.50 μm and had good agreement for its location with imaging spectrometer data. The IRSAT was then applied to discuss the effects of three operating conditions on IR signatures: (a afterburning; (b chamber pressure from ignition to cutoff; and (c minor changes in the ratio of hydroxyl-terminated polybutadiene (HTPB binder to ammonium perchlorate (AP oxidizer in propellant. Results show that afterburning effects can increase the size and shape of radiance images with enhancement of radiation intensity up to 40%. Also, the total IR irradiance in different bands can be characterized by a non-dimensional chamber pressure trace in which the maximum discrepancy is less than 13% during ignition and engine cutoff. An increase of chamber pressure can lead to more distinct diamonds, whose distance intervals are extended, and the position of the first diamond moving backwards. In addition, an increase in HTPB/AP causes a significant jump in spectral intensity. The incremental rates of radiance intensity integrated in each band are linear with the increase of HTPB

  13. Effect of Varying Hemodynamic and Vascular Conditions on Fractional Flow Reserve: An In Vitro Study.

    Science.gov (United States)

    Kolli, Kranthi K; Min, James K; Ha, Seongmin; Soohoo, Hilary; Xiong, Guanglei

    2016-06-30

    The aim of this study was to investigate the impact of varying hemodynamic conditions on fractional flow reserve (ratio of pressure distal [Pd] and proximal [Pa] to stenosis under hyperemia) in an in vitro setting. Failure to achieve maximal hyperemia and the choice of hyperemic agents may have differential effects on coronary hemodynamics and, consequently, on the determination of fractional flow reserve. An in vitro flow system was developed to experimentally model the physiological coronary circulation as flow-dependent stenosis resistance in series with variable downstream resistance. Five idealized models with 30% to 70% diameter stenosis severity were fabricated using VeroClear rigid material in an Objet260 Connex printer. Mean aortic pressure was maintained at 7 levels (60-140 mm Hg) from hypotension to hypertension using a needle valve that mimicked adjustable microcirculatory resistance. A range of physiological flow rates was applied by a steady flow pump and titrated by a flow sensor. The pressure drop and the pressure ratio (Pd/Pa) were assessed for the 7 levels of aortic pressure and differing flow rates. The in vitro experimental data were coupled with pressure-flow relationships from clinical data for populations with and without myocardial infarction, respectively, to evaluate fractional flow reserve. The curve for pressure ratio and flow rate demonstrated a quadratic relationship with a decreasing slope. The absolute decrease in fractional flow reserve in the group without myocardial infarction (with myocardial infarction) was on the order of 0.03 (0.02), 0.05 (0.02), 0.07 (0.05), 0.17 (0.13) and 0.20 (0.24), respectively, for 30%, 40%, 50%, 60%, and 70% diameter stenosis, for an increase in aortic pressure from 60 to 140 mm Hg. The fractional flow reserve value, an index of physiological stenosis significance, was observed to decrease with increasing aortic pressure for a given stenosis in this idealized in vitro experiment for vascular

  14. Solution of moving boundary problems with implicit boundary condition

    International Nuclear Information System (INIS)

    Moyano, E.A.

    1990-01-01

    An algorithm that solves numerically a model for studying one dimensional moving boundary problems, with implicit boundary condition, is described. Landau's transformation is used, in order to work with a fixed number of nodes at each instant. Then, it is necessary to deal with a parabolic partial differential equation, whose diffusive and convective terms have variable coefficients. The partial differential equation is implicitly discretized, using Laasonen's scheme, always stable, instead of employing Crank-Nicholson sheme, as it has been done by Ferris and Hill. Fixed time and space steps (Δt, Δξ) are used, and the iteration is made with variable positions of the interface, i.e. varying δs until a boundary condition is satisfied. The model has the same features of the oxygen diffusion in absorbing tissue. It would be capable of estimating time variant radiation treatments of cancerous tumors. (Author) [es

  15. Volatility spillover and time-varying conditional correlation between DDGS, corn, and soybean meal markets

    NARCIS (Netherlands)

    Etienne, Xiaoli L.; Trujillo-Barrera, Andrés; Hoffman, Linwood A.

    2017-01-01

    We find distiller's dried grains with solubles (DDGS) prices to be positively correlated with both corn and soybean meal prices in the long run. However, neither corn nor soybean meal prices respond to deviations from this long-run relationship. We also identify strong time-varying dynamic

  16. Benchmarking Close-range Structure from Motion 3D Reconstruction Software under Varying Capturing Conditions

    DEFF Research Database (Denmark)

    Nikolov, Ivan Adriyanov; Madsen, Claus B.

    2016-01-01

    Structure from Motion 3D reconstruction has become widely used in recent years in a number of fields such as industrial surface in- inspection, archeology, cultural heritage preservation and geomapping. A number of software solutions have been released using variations of this technique. In this ......Structure from Motion 3D reconstruction has become widely used in recent years in a number of fields such as industrial surface in- inspection, archeology, cultural heritage preservation and geomapping. A number of software solutions have been released using variations of this technique...

  17. Estimating time-varying conditional correlations between stock and foreign exchange markets

    Science.gov (United States)

    Tastan, Hüseyin

    2006-02-01

    This study explores the dynamic interaction between stock market returns and changes in nominal exchange rates. Many financial variables are known to exhibit fat tails and autoregressive variance structure. It is well-known that unconditional covariance and correlation coefficients also vary significantly over time and multivariate generalized autoregressive model (MGARCH) is able to capture the time-varying variance-covariance matrix for stock market returns and changes in exchange rates. The model is applied to daily Euro-Dollar exchange rates and two stock market indexes from the US economy: Dow-Jones Industrial Average Index and S&P500 Index. The news impact surfaces are also drawn based on the model estimates to see the effects of idiosyncratic shocks in respective markets.

  18. Nonlinear recurrent neural networks for finite-time solution of general time-varying linear matrix equations.

    Science.gov (United States)

    Xiao, Lin; Liao, Bolin; Li, Shuai; Chen, Ke

    2018-02-01

    In order to solve general time-varying linear matrix equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by solving differential equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Linear parameter varying control of wind turbines covering both partial load and full load conditions

    DEFF Research Database (Denmark)

    Østergaard, Kasper Zinck; Stoustrup, Jakob; Brath, Per

    2009-01-01

    operations tend to be ill-conditioned. The paper proposes a controller construction algorithm together with various remedies for improving the numerical conditioning the algorithm.The proposed algorithm is applied to the design of a LPV controller for wind turbines, and a comparison is made with a controller...... designed using classical techniques to conclude that an improvement in performance is obtained for the entire operating envelope....

  20. Numerical simulation of diurnally varying thermal environment in a street canyon under haze-fog conditions

    Science.gov (United States)

    Tan, Zijing; Dong, Jingliang; Xiao, Yimin; Tu, Jiyuan

    2015-10-01

    The impact of haze-fog on surface temperature, flow pattern, pollutant dispersion and pedestrian thermal comfort are investigated using computational fluid dynamics (CFD) approach based on a three-dimensional street canyon model under different haze-fog conditions. In this study, light extinction coefficient (Kex) is adopted to represent haze-fog pollution level. Numerical simulations are performed for different Kex values at four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST). The numerical results suggest that the surface temperature is strongly affected by the haze-fog condition. Surface heating induced by the solar radiation is enhanced by haze-fog, as higher surface temperature is observed under thicker haze-fog condition. Moreover, the temperature difference between sunlit and shadow surfaces is reduced, while that for the two shadow surfaces is slightly increased. Therefore, the surface temperature among street canyon facets becomes more evenly distributed under heavy haze-fog conditions. In addition, flow patterns are considerably altered by different haze-fog conditions, especially for the afternoon (1600 LST) case, in which thermal-driven flow has opposite direction as that of the wind-driven flow direction. Consequently, pollutants such as vehicular emissions will accumulate at pedestrian level, and pedestrian thermal comfort may lower under thicker haze-fog condition.

  1. Adaptive observer-based control for an IPMC actuator under varying humidity conditions

    Science.gov (United States)

    Bernat, Jakub; Kolota, Jakub

    2018-05-01

    As ionic polymer metal composites (IPMC) are increasingly applied to mechatronic systems, many new IPMC modeling efforts have been reported in the literature. The demands of rapidly growing technology has generated interest in advancing the intrinsic actuation and sensing capabilities of IPMC. Classical IPMC applications need constant hydration to operate. On the other hand, for IPMCs operating in air, the water content of the polymer varies with the humidity level of the ambient environment, which leads to its strong humidity-dependent behavior. Furthermore, decreasing water content over time plays a crucial role in the effectiveness of IPMC. Therefore, the primary challenge of this work is to accurately model this phenomenon. The principal contribution of the paper is a new IPMC model, which considers the change of moisture content. A novel nonlinear adaptive observer is designed to determine the unknown electric potential and humidity level in the polymer membrane. This approach effectively determines the moisture content of the IPMC during long-term continuous operation in air. This subsequently allows us to develop an effective back-stepping control algorithm that considers varying moisture content. Data from experiments are presented to support the effectiveness of the observation process, which is shown in illustrative examples.

  2. Performance of asphaltic concrete incorporating styrene butadiene rubber subjected to varying aging condition

    Science.gov (United States)

    Salah, Faisal Mohammed; Jaya, Ramadhansyah Putra; Mohamed, Azman; Hassan, Norhidayah Abdul; Rosni, Nurul Najihah Mad; Mohamed, Abdullahi Ali; Agussabti

    2017-12-01

    The influence of styrene butadiene rubber (SBR) on asphaltic concrete properties at different aging conditions was presented in this study. These aging conditions were named as un-aged, short-term, and long-term aging. The conventional asphalt binder of penetration grade 60/70 was used in this work. Four different levels of SBR addition were employed (i.e., 0 %, 1 %, 3 %, and 5 % by binder weight). Asphalt concrete mixes were prepared at selected optimum asphalt content (5 %). The performance was evaluated based on Marshall Stability, resilient modulus, and dynamic creep tests. Results indicated the improving stability and permanent deformation characteristics that the mixes modified with SBR polymer have under aging conditions. The result also showed that the stability, resilient modulus, and dynamic creep tests have the highest rates compared to the short-term aging and un-aged samples. Thus, the use of 5 % SBR can produce more durable asphalt concrete mixtures with better serviceability.

  3. The Metal-Halide Lamp Under Varying Gravity Conditions Measured by Emission and Laser Absorption Spectroscopy

    Science.gov (United States)

    Flikweert, A. J.; Nimalasuriya, T.; Kroesen, G. M. W.; Haverlag, M.; Stoffels, W. W.

    2009-11-01

    Diffusive and convective processes in the metal-halide lamp cause an unwanted axial colour segregation. Convection is induced by gravity. To understand the flow phenomena in the arc discharge lamp it has been investigated under normal laboratory conditions, micro-gravity (ISS and parabolic flights) and hyper-gravity (parabolic flights 2 g, centrifuge 1 g-10 g). The measurement techniques are webcam imaging, and emission and laser absorption spectroscopy. This paper aims to give an overview of the effect of different artificial gravity conditions on the lamp and compares the results from the three measurement techniques.

  4. Pre-Swirl Stator and Propeller Design for Varying Operating Conditions

    DEFF Research Database (Denmark)

    Saettone, Simone; Regener, Pelle Bo; Andersen, Poul

    2016-01-01

    blades ahead of the propeller.This paper describes the hydrodynamic design of apre-swirl stator with radially variable pitch, paired with aconventional propeller. The aim is to achieve the highest possible effciency in various operating conditions, and to avoid effciency penalties in off-design operation.......To investigate the propeller and stator designs and configurations in different operating conditions, the computationally inexpensive vortex-lattice method is used a sa first step to optimize the geometry in an initial parameter study. Then the flow over hull, stator and propelleris simulated in a CFD...

  5. Experimental study on Kd of 137Cs at varying suspended load conditions

    International Nuclear Information System (INIS)

    Jaison, T.J.; Jain, Abhishek; Patra, A.K.; Ravi, P.M.; Tripathi, R.M.

    2018-01-01

    137 Cs is one of the radionuclide likely to be released through liquid effluents from a nuclear facility. It is soluble in water, but its mobility in aquatic environments is highly retarded by its strong interaction with suspended sediment. The 137 Cs + sorption by suspended load, especially in the subtropics and tropics are not fully understood. Besides, according to IAEA document in emergency situation 137 Cs and 131 I being marker radionuclides, are easier to identify and representative of all the other radionuclides present. Hence a laboratory study is carried out on sorption of 137 Cs with varying silt load, using the upstream lake water and sediments to estimate site specific distribution coefficient (K d )

  6. Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions

    NARCIS (Netherlands)

    Henkel, S.G.; Ter Beek, A.S.; Steinsiek, S.; Stagge, S.; Bettenbrock, K.; Teixeira De Mattos, M.J.; Sauter, T.; Sawodny, O.; Ederer, M.

    2014-01-01

    For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear

  7. Adult Tea Green Leafhoppers, Empoasca onukii (Matsuda), Change Behaviors under Varying Light Conditions.

    Science.gov (United States)

    Shi, Longqing; Vasseur, Liette; Huang, Huoshui; Zeng, Zhaohua; Hu, Guiping; Liu, Xin; You, Minsheng

    2017-01-01

    Insect behaviors are often influenced by light conditions including photoperiod, light intensity, and wavelength. Understanding pest insect responses to changing light conditions may help with developing alternative strategies for pest control. Little is known about the behavioral responses of leafhoppers (Hemiptera: Cicadellidae) to light conditions. The behavior of the tea green leafhopper, Empoasca onukii Matsuda, was examined when exposed to different light photoperiods or wavelengths. Observations included the frequency of locomotion and cleaning activities, and the duration of time spent searching. The results suggested that under normal photoperiod both female and male adults were generally more active in darkness (i.e., at night) than in light. In continuous darkness (DD), the locomotion and cleaning events in Period 1 (7:00-19:00) were significantly increased, when compared to the leafhoppers under normal photoperiod (LD). Leafhoppers, especially females, changed their behavioral patterns to a two day cycle under DD. Under continuous illumination (continuous quartz lamp light, yellow light at night, and green light at night), the activities of locomotion, cleaning, and searching were significantly suppressed during the night (19:00-7:00) and locomotion activities of both females and males were significantly increased during the day (7:00-19:00), suggesting a shift in circadian rhythm. Our work suggests that changes in light conditions, including photoperiod and wavelength, can influence behavioral activities of leafhoppers, potentially affecting other life history traits such as reproduction and development, and may serve as a method for leafhopper behavioral control.

  8. Nonsimilar Solution for Shock Waves in a Rotational Axisymmetric Perfect Gas with a Magnetic Field and Exponentially Varying Density

    Science.gov (United States)

    Nath, G.; Sinha, A. K.

    2017-01-01

    The propagation of a cylindrical shock wave in an ideal gas in the presence of a constant azimuthal magnetic field with consideration for the axisymmetric rotational effects is investigated. The ambient medium is assumed to have the radial, axial, and azimuthal velocity components. The fluid velocities and density of the ambient medium are assumed to vary according to an exponential law. Nonsimilar solutions are obtained by taking into account the vorticity vector and its components. The dependences of the characteristics of the problem on the Alfven-Mach number and time are obtained. It is shown that the presence of a magnetic field has a decaying effect on the shock wave. The pressure and density are shown to vanish at the inner surface (piston), and hence a vacuum forms at the line of symmetry.

  9. Laboratory experiments on solute transport in bimodal porous media under cyclic precipitation-evaporation boundary conditions

    Science.gov (United States)

    Cremer, Clemens; Neuweiler, Insa

    2016-04-01

    Flow and solute transport in the shallow subsurface is strongly governed by atmospheric boundary conditions. Erratically varying infiltration and evaporation cycles lead to alternating upward and downward flow, as well as spatially and temporally varying water contents and associated hydraulic conductivity of the prevailing materials. Thus presenting a highly complicated, dynamic system. Knowledge of subsurface solute transport processes is vital to assess e.g. the entry of, potentially hazardous, solutes to the groundwater and nutrient uptake by plant roots and can be gained in many ways. Besides field measurements and numerical simulations, physical laboratory experiments represent a way to establish process understanding and furthermore validate numerical schemes. With the aim to gain a better understanding and to quantify solute transport in the unsaturated shallow subsurface under natural precipitation conditions in heterogeneous media, we conduct physical laboratory experiments in a 22 cm x 8 cm x 1 cm flow cell that is filled with two types of sand and apply cyclic infiltration-evaporation phases at the soil surface. Pressure at the bottom of the domain is kept constant. Following recent studies (Lehmann and Or, 2009; Bechtold et al., 2011a), heterogeneity is introduced by a sharp vertical interface between coarse and fine sand. Fluorescent tracers are used to i) qualitatively visualize transport paths within the domain and ii) quantify solute leaching at the bottom of the domain. Temporal and spatial variations in water content during the experiment are derived from x-ray radiographic images. Monitored water contents between infiltration and evaporation considerably changed in the coarse sand while the fine sand remained saturated throughout the experiments. Lateral solute transport through the interface in both directions at different depths of the investigated soil columns were observed. This depended on the flow rate applied at the soil surface and

  10. The in vitro fitness cost of antimicrobial resistance in Escherichia coli varies with the growth conditions

    DEFF Research Database (Denmark)

    Petersen, Andreas; Aarestrup, Frank Møller; Olsen, John Elmerdahl

    2009-01-01

    The objective of this study was to investigate the influence of stressful growth conditions on the fitness cost of antimicrobial resistance in Escherichia coli BJ4 caused by chromosomal mutations and plasmid acquisition. The fitness cost of chromosomal streptomycin resistance increased......H and at high-salt concentrations. Strains with an impaired rpoS demonstrated a reduced fitness only during growth in a high-salt concentration. In conclusion, it was demonstrated that bacterial fitness cost in association with antimicrobial resistance generally increases under stressful growth conditions....... However, the growth potential of bacteria with antimicrobial resistances did not increase in a straightforward manner in these in vitro experiments and is therefore probably even more difficult to predict in vivo....

  11. Characterization of Transient Plasma Ignition Flame Kernel Growth for Varying Inlet Conditions

    Science.gov (United States)

    2009-12-01

    from Intercity Manufacturing. Without their expertise in precision machining this thesis would not have been possible. Their countless hours spent...somewhere within the combustor due to the time required to produce the required conditions, and will be travelling at near Mach 5 speeds for most...atmospheric pressure. This sudden drop in pressure creates a rarefaction wave that travels forward in the combustor. The blowdown time for a 1 meter long

  12. Detection of respiratory viruses in shelter dogs maintained under varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Francielle Liz Monteiro

    Full Text Available Abstract Three dog shelters in Rio Grande do Sul were investigated for associations between the occurrence of respiratory viruses and shelter environmental conditions. Nasal secretions randomly collected during the cold season were tested via PCR, and this data collection was followed by nucleotide sequencing of the amplicons. In shelter #1 (poor sanitary and nutritional conditions, high animal density and constant contact between dogs, 78% (58/74 of the nasal samples were positive, 35% (26/74 of which were in single infections and 44% (32/74 of which were in coinfections. Shelters #2 and #3 had satisfactory sanitary and nutritional conditions, outdoors exercise areas (#2 and animal clustering by groups (#3. In shelter #2, 9% (3/35 of the samples were positive for Canine parainfluenza virus (CPIV, and 6% (2/35 were positive for Canid herpesvirus 1 (CaHV-1. In shelter #3, 9% (7/77 of the samples were positive for Canine adenovirus type 2 (CAdV-2, and 1% (1/77 were positive for Canine distemper virus (CDV. The amplicon sequences (CPIV and CDV nucleoprotein gene; CAdV-2 E3 gene; CaHV-1 glycoprotein B gene showed 94-100% nucleotide identity with GenBank sequences. Our results demonstrate that CPIV, CAdV-2 and CDV are common in dog shelters and that their frequencies appear to be related with environmental and nutritional conditions. These results indicate the need for control/prevention measures, including vaccination and environmental management, to minimize these infections and improve dog health.

  13. Wetting behavior of nonpolar nanotubes in simple dipolar liquids for varying nanotube diameter and solute-solvent interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Malay Kumar; Chandra, Amalendu, E-mail: amalen@iitk.ac.in [Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2015-01-21

    Atomistic simulations of model nonpolar nanotubes in a Stockmayer liquid are carried out for varying nanotube diameter and nanotube-solvent interactions to investigate solvophobic interactions in generic dipolar solvents. We have considered model armchair type single-walled nonpolar nanotubes with increasing radii from (5,5) to (12,12). The interactions between solute and solvent molecules are modeled by the well-known Lennard-Jones and repulsive Weeks-Chandler-Andersen potentials. We have investigated the density profiles and microscopic arrangement of Stockmayer molecules, orientational profiles of their dipole vectors, time dependence of their occupation, and also the translational and rotational motion of solvent molecules in confined environments of the cylindrical nanopores and also in their external peripheral regions. The present results of structural and dynamical properties of Stockmayer molecules inside and near atomistically rough nonpolar surfaces including their wetting and dewetting behavior for varying interactions provide a more generic picture of solvophobic effects experienced by simple dipolar liquids without any specific interactions such as hydrogen bonds.

  14. Mobility of Iron-Cyanide Complexes in a Humic Topsoil under Varying Redox Conditions

    Directory of Open Access Journals (Sweden)

    Thilo Rennert

    2009-01-01

    Full Text Available The potentially toxic Fe-CN complexes ferricyanide, [FeIII(CN6]3−, and ferrocyanide, [FeII(CN6]4−, undergo a variety of redox processes in soil, which affect their mobility. We carried out microcosm experiments with suspensions of a humic topsoil (pH 5.3; Corg 107 g kg-1 to which we added ferricyanide (20 mg l-1. We varied the redox potential (EH from −280 to 580 mV by using O2, N2 and glucose. The decrease of EH led to decreasing concentrations of Fe-CN complexes and partial reductive dissolution of (hydrous Fe and Mn oxides. The dynamics of aqueous Fe-CN concentrations was characterized by decreasing concentrations when the pH rose and the EH dropped. We attribute these dependencies to adsorption on organic surfaces, for which such a pH/EH behavior has been shown previously. Adsorption was reversible, because when the pH and EH changed into the opposite direction, desorption occurred. This study demonstrates the possible impact of soil organic matter on the fate of Fe-CN complexes in soil.

  15. Transient response of a polymer electrolyte membrane fuel cell subjected to time-varying modulating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Noorani, S.; Shamim, T. [Michigan-Dearborn Univ., Dearborn, MI (United States). Dept. of Mechanical Engineering

    2009-07-01

    In order for fuel cells to compete with internal combustion engines, they must have significant advantages in terms of overall efficiency, weight, packaging, safety and cost. A key requirement is its ability to operate under highly transient conditions during start-up, acceleration, and deceleration with stable performance. Therefore, a better understanding of fuel cell dynamic behaviour is needed along with better water management and distributions inside the cell. Therefore, this study investigated the effect of transient conditions on water distribution inside a polymer electrolyte membrane (PEM) cell. A macroscopic single-fuel cell based, one-dimensional, isothermal mathematical model was used to study the effect of modulating cell voltage on the water distribution of anode, cathode, catalyst layers, and membrane. Compared to other existing models, this model did not rely on the non-physical assumption of the uptake curve equilibrium between the pore vapour and ionomer water in the catalyst layers. Instead, the transition between the two phases was modeled as a finite-rate equilibration process. The modulating conditions were simulated by forcing the temporal variations in fuel cell voltage. The results revealed that cell voltage modulations cause a departure in the cell behaviour from its steady behaviour, and the finite-rate equilibration between the catalyst vapour and liquid water can be a factor in determining the cell response. The cell response is also affected by the modulating frequency and amplitude. The peak cell response was observed at low frequencies. Keywords: fuel cell, water transport, dynamic behaviour, numerical simulations. 9 refs., 1 tab., 5 figs.

  16. Oral complementary medicine and alternative practitioner use varies across chronic conditions and attitudes to risk

    Directory of Open Access Journals (Sweden)

    Robert J Adams

    2010-11-01

    Full Text Available Robert J Adams1, Sarah L Appleton1, Antonia Cole2, Tiffany K Gill3, Anne W Taylor3, Catherine L Hill11The Health Observatory, 2Rheumatology Unit, 3Population Research and Outcomes Unit, SA Health, The University of Adelaide Discipline of Medicine, Queen Elizabeth Hospital, Woodville, AustraliaObjectives: To determine whether chronic conditions and patient factors, such as risk perception and decision-making preferences, are associated with complementary medicine and alternative practitioner use in a representative longitudinal population cohort.Participants and setting: Analysis of data from Stage 2 of the North West Adelaide Health Study of 3161 adults who attended a study clinic visit in 2004–2006. The main outcome measures were the medications brought by participants to the study clinic visit, chronic health conditions, attitudes to risk, levels of satisfaction with conventional medicine, and preferred decision-making style.Results: At least one oral complementary medicine was used by 27.9% of participants, and 7.3% were visiting alternative practitioners (naturopath, osteopath. Oral complementary medicine use was significantly associated with arthritis, osteoporosis, and mental health conditions, but not with other chronic conditions. Any pattern of complementary medicine use was generally significantly associated with female gender, age at least 45 years, patient-driven decision-making preferences (odds ratio [OR] 1.38, 95% confidence interval [CI]: 1.08–1.77, and frequent general practitioner visits (>five per year; OR 3.62, 95% CI: 2.13–6.17. Alternative practitioner visitors were younger, with higher levels of education (diploma/trade [OR 1.88, 95% CI: 1.28–2.76], bachelor’s degree [OR 1.77, 95% CI: 1.11–2.82], income > $80,000 (OR 2.28, 95% CI: 1.26–4.11, female gender (OR 3.15, 95% CI: 2.19–4.52, joint pain not diagnosed as arthritis (OR 1.68, 95% CI: 1.17–2.41, moderate to severe depressive symptoms (OR 2.15, 95% CI

  17. Nitrous Oxide Production and Fluxes from Coastal Sediments under Varying Environmental Conditions

    Science.gov (United States)

    Ziebis, W.; Wankel, S. D.; de Beer, D.; Dentinger, J.; Buchwald, C.; Charoenpong, C.

    2014-12-01

    Although coastal zones represent important contributors to the increasing levels of atmospheric nitrous oxide (N2O), it is still unclear which role benthic processes play and whether marine sediments represent sinks or sources for N2O, since interactions among closely associated microbial groups lead to a high degree of variability. In addition, coastal areas are extremely dynamic regions, often exposed to increased nutrient loading and conditions of depleted oxygen. We investigated benthic N2O fluxes and how environmental conditions affect N2O production in different sediments at 2 different geographical locations (German Wadden Sea, a California coastal lagoon). At each location, a total of 32 sediment cores were taken in areas that differed in sediment type, organic content and pore-water nutrient concentrations, as well as in bioturbation activity. Parallel cores were incubated under in-situ conditions, low oxygen and increased nitrate levels for 10 days. Zones of N2O production and consumption were identified in intact cores by N2O microprofiles at the beginning and end of the experiments. In a collaborative effort to determine the dominant sources of N2O, samples were taken throughout the course of the experiments for the determination of the isotopic composition of N2O (as well as nitrate, nitrite and ammonium). Our results indicate that both, nitrate addition and low oxygen conditions in the overlying water, caused an increase of subsurface N2O production in most sediments, with a high variability between different sediment types. N2O production in the sediments was accompanied by N2O consumption, reducing the fluxes to the water column. In general, organic rich sediments showed the strongest response to environmental changes with increased production and efflux of N2O into the overlying water. Bioturbation activity added to the complexity of N2O dynamics by an increase in nitrification-denitrification processes, as well as enhanced pore-water transport

  18. Oral complementary medicine and alternative practitioner use varies across chronic conditions and attitudes to risk.

    Science.gov (United States)

    Adams, Robert J; Appleton, Sarah L; Cole, Antonia; Gill, Tiffany K; Taylor, Anne W; Hill, Catherine L

    2010-11-08

    To determine whether chronic conditions and patient factors, such as risk perception and decision-making preferences, are associated with complementary medicine and alternative practitioner use in a representative longitudinal population cohort. Analysis of data from Stage 2 of the North West Adelaide Health Study of 3161 adults who attended a study clinic visit in 2004-2006. The main outcome measures were the medications brought by participants to the study clinic visit, chronic health conditions, attitudes to risk, levels of satisfaction with conventional medicine, and preferred decision-making style. At least one oral complementary medicine was used by 27.9% of participants, and 7.3% were visiting alternative practitioners (naturopath, osteopath). Oral complementary medicine use was significantly associated with arthritis, osteoporosis, and mental health conditions, but not with other chronic conditions. Any pattern of complementary medicine use was generally significantly associated with female gender, age at least 45 years, patient-driven decision-making preferences (odds ratio [OR] 1.38, 95% confidence interval [CI]: 1.08-1.77), and frequent general practitioner visits (>five per year; OR 3.62, 95% CI: 2.13-6.17). Alternative practitioner visitors were younger, with higher levels of education (diploma/trade [OR 1.88, 95% CI: 1.28-2.76], bachelor's degree [OR 1.77, 95% CI: 1.11-2.82], income >$80,000 (OR 2.28, 95% CI: 1.26-4.11), female gender (OR 3.15, 95% CI: 2.19-4.52), joint pain not diagnosed as arthritis (OR 1.68, 95% CI: 1.17-2.41), moderate to severe depressive symptoms (OR 2.15, 95% CI: 1.04-4.46), and risk-taking behavior (3.26, 1.80-5.92), or low-to-moderate risk aversion (OR 2.08, 95% CI: 1.26-4.11). Although there is widespread use of complementary medicines in the Australian community, there are differing patterns of use between those using oral complementary medicines and those using alternative practitioners.

  19. Engineered pipeline field joint coating solutions for demanding conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lwemuchi, Andre L.; Gudme, Carl C.; Buchanan, Robert [Canusa-CPS, Toronto, OT (Canada)

    2009-12-19

    Trends in the oil and gas pipeline industry see that the demand for new technologies and engineered solutions for pipeline external coatings are increasing. In general, superior mechanical resistance and long term performance are being required in addition to operating at higher temperatures. This demand for more robust coatings has been created because of factors such as more remote fields, deep onshore reservoirs, deep water offshore fields and heavy oil that must be pumped at higher temperatures. The development of new techniques for pipeline construction is also exposing the coatings to more aggressive construction conditions. Because of this, the use of three layer and multi-layer polypropylene mainline coating systems have been growing considerably. Following this trend, the field joint coating manufacturers developed polypropylene systems and more recently had to work on engineered solutions required for recent offshore projects in Europe where very thick polypropylene field joint heat-shrinkable systems were provided. In addition, projects in remote locations such as the recently completed projects in the Brazilian Amazon required special logistics and field services. The growth of the mining industry in South America with slurry pipelines constructed in the recent years also demanded thicker, more robust coatings. The popularization of directional drilling and shore approach applications moved the industry to develop improved abrasion resistant coating systems such as using sacrificial elements to protect the primary coating integrity after the pipeline pull. PETROBRAS plans to replace existing thermally insulated pipelines crossing Great Sao Paulo. Therefore, pumping heavy oil at high temperatures created the need to develop improved mainline and field joint coatings to avoid having the same sort of problems they are facing in existing thermally insulated lines. Due to these needs, the field joint coating manufactures have been challenged to provide

  20. Schema bias in source monitoring varies with encoding conditions: support for a probability-matching account.

    Science.gov (United States)

    Kuhlmann, Beatrice G; Vaterrodt, Bianca; Bayen, Ute J

    2012-09-01

    Two experiments examined reliance on schematic knowledge in source monitoring. Based on a probability-matching account of source guessing, a schema bias will only emerge if participants do not have a representation of the source-item contingency in the study list, or if the perceived contingency is consistent with schematic expectations. Thus, the account predicts that encoding conditions that affect contingency detection also affect schema bias. In Experiment 1, the schema bias commonly found when schematic information about the sources is not provided before encoding was diminished by an intentional source-memory instruction. In Experiment 2, the depth of processing of schema-consistent and schema-inconsistent source-item pairings was manipulated. Participants consequently overestimated the occurrence of the pairing type they processed in a deep manner, and their source guessing reflected this biased contingency perception. Results support the probability-matching account of source guessing. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  1. Rimsulfuron in Soil: Effects on Microbiological Properties under Varying Soil Conditions

    Directory of Open Access Journals (Sweden)

    Ljiljana Radivojević

    2011-01-01

    Full Text Available The effects of rimsulfuron a sulfonylurea herbicide on the growth and activity of soil microorganisms under laboratory conditions was investigated in two soils. The application rates were: 0.2, 2.0 and 20.0 mg a.i kg-1 soil. The lowest concentration tested was the label rate (0.2 mg a.i kg-1, and the other two were ten and hundred timeshigher. No adverse effects on microbiological processes were observed for the label rate. Decrease in microbial biomass carbon, dehydrogenase activity, fungi and bacteria in comparison with untreated control, were found at higher rates. The magnitude of these effects were generally slight and transitory.

  2. Numerical modeling of solute transport in a sand tank physical model under varying hydraulic gradient and hydrological stresses

    Science.gov (United States)

    Atlabachew, Abunu; Shu, Longcang; Wu, Peipeng; Zhang, Yongjie; Xu, Yang

    2018-03-01

    This laboratory study improves the understanding of the impacts of horizontal hydraulic gradient, artificial recharge, and groundwater pumping on solute transport through aquifers. Nine experiments and numerical simulations were carried out using a sand tank. The variable-density groundwater flow and sodium chloride transport were simulated using the three-dimensional numerical model SEAWAT. Numerical modelling results successfully reproduced heads and concentrations observed in the sand tank. A higher horizontal hydraulic gradient enhanced the migration of sodium chloride, particularly in the groundwater flow direction. The application of constant artificial recharge increased the spread of the sodium chloride plume in both the longitudinal and lateral directions. In addition, groundwater pumping accelerated spreading of the sodium chloride plume towards the pumping well. Both higher hydraulic gradient and pumping rate generated oval-shaped plumes in the horizontal plane. However, the artificial recharge process produced stretched plumes. These effects of artificial recharge and groundwater pumping were greater under higher hydraulic gradient. The concentration breakthrough curves indicated that emerging solutions never attained the concentration of the originally injected solution. This is probably because of sorption of sodium chloride onto the silica sand and/or the exchange of sodium chloride between the mobile and immobile liquid domains. The fingering and protruding plume shapes in the numerical models constitute instability zones produced by buoyancy-driven flow. Overall, the results have substantiated the influences of hydraulic gradient, boundary condition, artificial recharge, pumping rate and density differences on solute transport through a homogeneous unconfined aquifer. The implications of these findings are important for managing liquid wastes.

  3. Hydroxyisohexyl 3-cyclohexene carboxaldehyde (lyral) in patch test preparations under varied storage conditions.

    Science.gov (United States)

    Hamann, Dathan; Hamann, Carsten R; Zimerson, Erik; Bruze, Magnus

    2013-01-01

    The common practice of preparing patch tests in advance has recently been called into question by researchers. It has been established that fragrance compounds are volatile and their testing efficacy may be affected by storage conditions and preparation. Allergens in fragrance mix I rapidly decrease in concentration after preapplication to test chambers. This study aimed to investigate the volatility of hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) in petrolatum when stored in test chambers and to explore the correlation between vapor pressure and allergen loss in petrolatum during preparation and storage. Standardized HICC in petrolatum was prepared and stored in IQ Chambers and Finn Chambers with covers at 5°C, 25°C, and 35°C, and concentration was analyzed at intervals for up to 9 days using gel permeation chromatography. Changes in HICC concentrations were not statistically significant at 8 hours at 5°C, 25°C, and 35°C. After 9 days, HICC concentrations were found to fall approximately 30% when stored at 35°C, 10% at 25°C, and less than 5% at 5°C. There was no significant difference between IQ and Finn chambers. Hydroxyisohexyl 3-cyclohexene carboxaldehyde concentrations are more stable in petrolatum than many other studied fragrance allergens, but HICC is still at risk for decreasing concentration when exposed to ambient air or heat for prolonged periods.

  4. Vibration Analysis of a Tire in Ground Contact under Varied Conditions

    Directory of Open Access Journals (Sweden)

    Karakus Murat

    2017-03-01

    Full Text Available The effect of three different factors, which are inflation pressure, vertical load and coefficient of friction on the natural frequencies of a tire (175/70 R13 has been studied. A three dimensional tire model is constructed, using four different material properties and parts in the tire. Mechanical properties of the composite parts are evaluated. After investigating the free vibration, contact analysis is carried out. A concrete block and the tire are modelled together, using three different coefficients of friction. Experiments are run under certain conditions to check the accuracy of the numerical model. The natural frequencies are measured to describe free vibration and vibration of the tire contacted by ground, using a damping monitoring method. It is seen, that experimental and numerical results are in good agreement. On the other hand, investigating the impact of three different factors together is quite difficult on the natural frequencies. When some of these factors are assumed to be constant and the variables are taken one by one, it is easier to assess the effects.

  5. Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hedtke, S.F.; West, C.W.; Allen, K.N.; Norberg-King, T.J.; Mount, D.I.

    1986-06-01

    The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 values ranging from 85 micrograms/L for the white sucker Catastomus commersoni during the summer to greater than 7770 micrograms/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. The greatest variation in toxicity was due to species sensitivity. Within a given, season there was as much as a 40-fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14-fold. There were also substantial differences in acute-chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.

  6. Comparison of the kinetics of different Markov models for ligand binding under varying conditions

    International Nuclear Information System (INIS)

    Martini, Johannes W. R.; Habeck, Michael

    2015-01-01

    We recently derived a Markov model for macromolecular ligand binding dynamics from few physical assumptions and showed that its stationary distribution is the grand canonical ensemble [J. W. R. Martini, M. Habeck, and M. Schlather, J. Math. Chem. 52, 665 (2014)]. The transition probabilities of the proposed Markov process define a particular Glauber dynamics and have some similarity to the Metropolis-Hastings algorithm. Here, we illustrate that this model is the stochastic analog of (pseudo) rate equations and the corresponding system of differential equations. Moreover, it can be viewed as a limiting case of general stochastic simulations of chemical kinetics. Thus, the model links stochastic and deterministic approaches as well as kinetics and equilibrium described by the grand canonical ensemble. We demonstrate that the family of transition matrices of our model, parameterized by temperature and ligand activity, generates ligand binding kinetics that respond to changes in these parameters in a qualitatively similar way as experimentally observed kinetics. In contrast, neither the Metropolis-Hastings algorithm nor the Glauber heat bath reflects changes in the external conditions correctly. Both converge rapidly to the stationary distribution, which is advantageous when the major interest is in the equilibrium state, but fail to describe the kinetics of ligand binding realistically. To simulate cellular processes that involve the reversible stochastic binding of multiple factors, our pseudo rate equation model should therefore be preferred to the Metropolis-Hastings algorithm and the Glauber heat bath, if the stationary distribution is not of only interest

  7. Comparison of the kinetics of different Markov models for ligand binding under varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Johannes W. R., E-mail: jmartin2@gwdg.de [Max Planck Institute for Developmental Biology, Tübingen (Germany); Felix Bernstein Institute for Mathematical Statistics in the Biosciences, University of Göttingen, Göttingen (Germany); Habeck, Michael, E-mail: mhabeck@gwdg.de [Felix Bernstein Institute for Mathematical Statistics in the Biosciences, University of Göttingen, Göttingen (Germany); Max Planck Institute for Biophysical Chemistry, Göttingen (Germany)

    2015-03-07

    We recently derived a Markov model for macromolecular ligand binding dynamics from few physical assumptions and showed that its stationary distribution is the grand canonical ensemble [J. W. R. Martini, M. Habeck, and M. Schlather, J. Math. Chem. 52, 665 (2014)]. The transition probabilities of the proposed Markov process define a particular Glauber dynamics and have some similarity to the Metropolis-Hastings algorithm. Here, we illustrate that this model is the stochastic analog of (pseudo) rate equations and the corresponding system of differential equations. Moreover, it can be viewed as a limiting case of general stochastic simulations of chemical kinetics. Thus, the model links stochastic and deterministic approaches as well as kinetics and equilibrium described by the grand canonical ensemble. We demonstrate that the family of transition matrices of our model, parameterized by temperature and ligand activity, generates ligand binding kinetics that respond to changes in these parameters in a qualitatively similar way as experimentally observed kinetics. In contrast, neither the Metropolis-Hastings algorithm nor the Glauber heat bath reflects changes in the external conditions correctly. Both converge rapidly to the stationary distribution, which is advantageous when the major interest is in the equilibrium state, but fail to describe the kinetics of ligand binding realistically. To simulate cellular processes that involve the reversible stochastic binding of multiple factors, our pseudo rate equation model should therefore be preferred to the Metropolis-Hastings algorithm and the Glauber heat bath, if the stationary distribution is not of only interest.

  8. Modeling Quantum Dot Nanoparticle Fate and Transport in Saturated Porous Media under Varying Flow Conditions

    Science.gov (United States)

    Becker, M. D.; Wang, Y.; Englehart, J.; Pennell, K. D.; Abriola, L. M.

    2010-12-01

    As manufactured nanomaterials become more prevalent in commercial and industrial applications, the development of mathematical models capable of predicting nanomaterial transport and retention in subsurface systems is crucial to assessing their fate and distribution in the environment. A systematic modeling approach based on a modification of clean-bed filtration theory was undertaken to elucidate mechanisms governing the transport and deposition behavior of quantum dots in saturated quartz sand as a function of grain size and flow velocity. The traditional deposition governing equation, which assumes irreversible attachment by a first-order rate (katt), was modified to include a maximum or limiting retention capacity (Smax) and first-order detachment of particles from the solid phase (kdet). Quantum dot mobility experiments were performed in columns packed with three size fractions of Ottawa sand (d50 = 125, 165, and 335 μm) at two different pore-water velocities (0.8 m/d and 7.6 m/d). The CdSe quantum dots in a CdZnS shell and polyacrylic acid coating were negatively charged (zeta potential measured ca. -35 mV) with a hydrodynamic diameter of approximately 30 nm. Fitted values of katt, Smax, and kdet were obtained for each transport and deposition experiment through the implementation of a nonlinear least-squares routine developed to fit the model to experimental breakthrough and retention data via multivariate optimization. Fitted attachment rates and retention capacities increased exponentially with decreasing grain size at both flow rates, while no discernable trend was apparent for the fitted detachment rates. Maximum retention capacity values were plotted against a normalized mass flux expression, which accounts for flow conditions and grain size. A power function fit to the data yielded a dependence that was consistent with a previous study undertaken with fullerene nanoparticles.

  9. The effect of probe choice and solution conditions on the apparent photoreactivity of dissolved organic matter.

    Science.gov (United States)

    Maizel, Andrew C; Remucal, Christina K

    2017-08-16

    Excited triplet states of dissolved organic matter ( 3 DOM) are quantified directly with the species-specific probes trans,trans-hexadienoic acid (HDA) and 2,4,6-trimethylphenol (TMP), and indirectly with the singlet oxygen ( 1 O 2 ) probe furfuryl alcohol (FFA). Although previous work suggests that these probe compounds may be sensitive to solution conditions, including dissolved organic carbon concentration ([DOC]) and pH, and may quantify different 3 DOM subpopulations, the probes have not been systematically compared. Therefore, we quantify the apparent photoreactivity of diverse environmental waters using HDA, TMP, and FFA. By conducting experiments under ambient [DOC] and pH, with standardized [DOC] and pH, and with solid phase extraction isolates, we demonstrate that much of the apparent dissimilarity in photochemical measurements is attributable to solution conditions, rather than intrinsic differences in 3 DOM production. In general, apparent quantum yields (Φ 1 O 2 ≥ Φ 3 DOM,TMP ≫ Φ 3 DOM,HDA ) and pseudo-steady state concentrations ([ 1 O 2 ] ss > [ 3 DOM] ss,TMP > [ 3 DOM] ss,HDA ) show consistent relationships in all waters under standardized conditions. However, intrinsic differences in 3 DOM photoreactivity are apparent between DOM from diverse sources, as seen in the higher Φ 1 O 2 and lower Φ 3 DOM,TMP of wastewater effluents compared with oligotrophic lakes. Additionally, while conflicting trends in photoreactivity are observed under ambient conditions, all probes observe quantum yields increasing from surface wetlands to terrestrially influenced waters to oligotrophic lakes under standardized conditions. This work elucidates how probe selection and solution conditions influence the apparent photoreactivity of environmental waters and confirms that 3 DOM or 1 O 2 probes cannot be used interchangeably in waters that vary in [DOC], pH, or DOM source.

  10. Solute concentration at a well in non-Gaussian aquifers under constant and time-varying pumping schedule

    Science.gov (United States)

    Libera, Arianna; de Barros, Felipe P. J.; Riva, Monica; Guadagnini, Alberto

    2017-10-01

    Our study is keyed to the analysis of the interplay between engineering factors (i.e., transient pumping rates versus less realistic but commonly analyzed uniform extraction rates) and the heterogeneous structure of the aquifer (as expressed by the probability distribution characterizing transmissivity) on contaminant transport. We explore the joint influence of diverse (a) groundwater pumping schedules (constant and variable in time) and (b) representations of the stochastic heterogeneous transmissivity (T) field on temporal histories of solute concentrations observed at an extraction well. The stochastic nature of T is rendered by modeling its natural logarithm, Y = ln T, through a typical Gaussian representation and the recently introduced Generalized sub-Gaussian (GSG) model. The latter has the unique property to embed scale-dependent non-Gaussian features of the main statistics of Y and its (spatial) increments, which have been documented in a variety of studies. We rely on numerical Monte Carlo simulations and compute the temporal evolution at the well of low order moments of the solute concentration (C), as well as statistics of the peak concentration (Cp), identified as the environmental performance metric of interest in this study. We show that the pumping schedule strongly affects the pattern of the temporal evolution of the first two statistical moments of C, regardless the nature (Gaussian or non-Gaussian) of the underlying Y field, whereas the latter quantitatively influences their magnitude. Our results show that uncertainty associated with C and Cp estimates is larger when operating under a transient extraction scheme than under the action of a uniform withdrawal schedule. The probability density function (PDF) of Cp displays a long positive tail in the presence of time-varying pumping schedule. All these aspects are magnified in the presence of non-Gaussian Y fields. Additionally, the PDF of Cp displays a bimodal shape for all types of pumping

  11. X-ray absorption spectroscopic study of trivalent and tetravalent actinides in solution at varying pH values

    Energy Technology Data Exchange (ETDEWEB)

    Brendebach, B.; Banik, N.L.; Marquardt, C.M.; Rothe, J.; Denecke, M.A.; Geckeis, H. [Forschungszentrum Karlsruhe (Germany). Inst. fuer Nukleare Entsorgung

    2009-07-01

    We perform X-ray absorption spectroscopy (XAS) investigations to monitor the stabilization of redox sensitive trivalent and tetravalent actinide ions in solution at acidic conditions in a pH range from 0 to 3 after treatment with holding reductants, hydroxylamine hydrochloride (NH{sub 2}OHHCl) and Rongalite (sodium hydroxymethanesulfinate, CH{sub 3}NaO{sub 3}S). X-ray absorption near edge structure (XANES) measurements clearly demonstrate the stability of the actinide species for several hours under the given experimental conditions. Hence, structural parameters can be accurately derived by extended X-ray absorption fine structure (EXAFS) investigations. The coordination structure of oxygen atoms belonging to water ligands surrounding the actinide ions does not change with increasing pH value (approximately 11 O atoms at 2.42 A in the case of U(IV) at pH 1, 9 0 atoms at 2.52 A for Np(III) at pH 1.5, and 10 O atoms at 2.49 A for Pu(III) up to pH 3), indicating that hydrolysis reactions are suppressed under the given chemical conditions. (orig.)

  12. Solute transport in streams of varying morphology inferred from a high resolution network of potentiometric wireless chloride sensors

    Science.gov (United States)

    Klaus, Julian; Smettem, Keith; Pfister, Laurent; Harris, Nick

    2017-04-01

    There is ongoing interest in understanding and quantifying the travel times and dispersion of solutes moving through stream environments, including the hyporheic zone and/or in-channel dead zones where retention affects biogeochemical cycling processes that are critical to stream ecosystem functioning. Modelling these transport and retention processes requires acquisition of tracer data from injection experiments where the concentrations are recorded downstream. Such experiments are often time consuming and costly, which may be the reason many modelling studies of chemical transport have tended to rely on relatively few well documented field case studies. This leads to the need of fast and cheap distributed sensor arrays that respond instantly and record chemical transport at points of interest on timescales of seconds at various locations in the stream environment. To tackle this challenge we present data from several tracer experiments carried out in the Attert river catchment in Luxembourg employing low-cost (in the order of a euro per sensor) potentiometric chloride sensors in a distributed array. We injected NaCl under various baseflow conditions in streams of different morphologies and observed solute transport at various distances and locations. This data is used to benchmark the sensors to data obtained from more expensive electrical conductivity meters. Furthermore, the data allowed spatial resolution of hydrodynamic mixing processes and identification of chemical 'dead zones' in the study reaches.

  13. Varying the agglomeration position of particles in a micro-channel using Acoustic Radiation Force beyond the resonance condition.

    Science.gov (United States)

    Dron, Olivier; Aider, Jean-Luc

    2013-09-01

    It is well-known that particles can be focused at mid-height of a micro-channel using Acoustic Radiation Force (ARF) tuned at the resonance frequency (h=λ/2). The resonance condition is a strong limitation to the use of acoustophoresis (particles manipulation using acoustic force) in many applications. In this study we show that it is possible to focus the particles anywhere along the height of a micro-channel just by varying the acoustic frequency, in contradiction with the resonance condition. This result has been thoroughly checked experimentally. The different physical properties as well as wall materials have been changed. The wall materials is finally the only critical parameters. One of the specificity of the micro-channel is the thickness of the carrier and reflector layer. A preliminary analysis of the experimental results suggests that the acoustic focusing beyond the classic resonance condition can be explained in the framework of the multilayered resonator proposed by Hill [1]. Nevertheless, further numerical studies are needed in order to confirm and fully understand how the acoustic pressure node can be moved over the entire height of the micro channel by varying the acoustic frequency. Despite some uncertainties about the origin of the phenomenon, it is robust and can be used for improved acoustic sorting or manipulation of particles or biological cells in confined set-ups. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

    Directory of Open Access Journals (Sweden)

    Lixin Chen

    Full Text Available The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations.We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP. The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1 the influence of tree species and size on transpiration, and 2 the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH and tree canopy transpiration amount (E(c was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c at VPD = 1 kPa (G(cref and the G(c sensitivity to VPD (-dG(c/dlnVPD across studied species as well as under contrasting soil water and R(s conditions in the urban area.We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref.

  15. Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

    Science.gov (United States)

    Chen, Lixin; Zhang, Zhiqiang; Ewers, Brent E

    2012-01-01

    The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations. We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP). The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1) the influence of tree species and size on transpiration, and 2) the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH) and tree canopy transpiration amount (E(c)) was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c) at VPD = 1 kPa (G(cref)) and the G(c) sensitivity to VPD (-dG(c)/dlnVPD) across studied species as well as under contrasting soil water and R(s) conditions in the urban area. We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref).

  16. Comparison of creep behavior under varying load/temperature conditions between Hastelloy XR alloys with different boron content levels

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Shindo, Masami; Tanabe, Tatsuhiko; Nakasone, Yuji.

    1996-01-01

    In the design of the high-temperature components, it is often required to predict the creep rupture life under the conditions in which the stress and/or temperature may vary by using the data obtained with the constant load and temperature creep rupture tests. Some conventional creep damage rules have been proposed to meet the above-mentioned requirement. Currently only limited data are available on the behavior of Hastelloy XR, which is a developed alloy as the structural material for high-temperature components of the High-Temperature Engineering Test Reactor (HTTR), under varying stress and/or temperature creep conditions. Hence a series of constant load and temperature creep rupture tests as well as varying load and temperature creep rupture tests was carried out on two kinds of Hastelloy XR alloys whose boron content levels are different, i.e., below 10 and 60 mass ppm. The life fraction rule completely fails in the prediction of the creep rupture life of Hastelloy XR with 60 mass ppm boron under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR with below 10 mass ppm boron. The change of boron content level of the material during the tests is the most probable source of impairing the applicability of the life fraction rule to Hastelloy XR whose boron content level is 60 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the two stage creep test conditions from 1000 to 900degC. The trend observed in the two stage creep tests from 900 to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (J.P.N.)

  17. Facet-Dependent Oxidative Goethite Growth As a Function of Aqueous Solution Conditions.

    Science.gov (United States)

    Strehlau, Jennifer H; Stemig, Melissa S; Penn, R Lee; Arnold, William A

    2016-10-04

    Nitroaromatic compounds are groundwater pollutants that can be degraded through reactions with Fe(II) adsorbed on iron oxide nanoparticles, although little is known about the evolving reactivity of the minerals with continuous pollutant exposure. In this work, Fe(II)/goethite reactivity toward 4-chloronitrobenzene (4-ClNB) as a function of pH, organic matter presence, and reactant concentrations was explored using sequential-spike batch reactors. Reaction rate constants were smaller with lower pH, introduction of organic matter, and diluted reactant concentrations as compared to a reference condition. Reaction rate constants did not change with the number of 4-ClNB spikes for all reaction conditions. Under all conditions, oxidative goethite growth was demonstrated through X-ray diffraction, magnetic characterization, and transmission electron microscopy. Nonparametric statistics were applied to compare histograms of lengths and widths of goethite nanoparticles as a function of varied solution conditions. The conditions that slowed the reaction also resulted in statistically shorter and wider particles than for the faster reactions. Additionally, added organic matter interfered with particle growth on the favorable {021} faces to a greater extent, with statistically reduced rate of growth on the tip facets and increased rate of growth on the side facets. These data demonstrate that oxidative growth of goethite in aqueous systems is dependent on major groundwater variables, such as pH and the presence of organic matter, which could lead to the evolving reactivity of goethite particles in natural environments.

  18. Composition characteristics and regularities of dissolving of hydroxyapatite materials obtained in water solutions with varied content of silicate ions

    Science.gov (United States)

    Solonenko, A. P.

    2018-01-01

    Research aimed at developing new bioactive materials for the repair of defects in bone tissues, do not lose relevance due to the strengthening of the regenerative approach in medicine. From this point of view, materials based on calcium phosphates, including silicate ions, consider as one of the most promising group of substances. Methods of synthesis and properties of hydroxyapatite doped with various amounts of SiO4 4- ions are described in literature. In the present work synthesis of a solid phase in the systems Ca(NO3)2 - (NH4)2HPO4 - Na2SiO3 - NH4OH - H2O (Cca/CP = 1.70) performed with a wide range of sodium silicate additive concentration (y = CSi/CP = 0 ÷ 5). It is established that under the studied conditions at y ≥ 0.3 highly dispersed poorly crystallized apatite containing isomorphic impurities of CO3 2- and SiO4 4- precipitates in a mixture with calcium hydrosilicate and SiO2. It is shown that the resulting composites can gradually dissolve in physiological solution and initiate passive formation of the mineral component of hard tissues.

  19. On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

    OpenAIRE

    John A. D. Appleby

    2010-01-01

    We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. ...

  20. Improving conditions for reuse of design solutions - by means of a context based solution library

    DEFF Research Database (Denmark)

    Mortensen, Niels Henrik; Grothe-Møller, Thorkild; Andreasen, Mogens Myrup

    1997-01-01

    Among the most important reasoning mechanisms in design is reasoning by analogy. One precondition for being able to reason about the properties and functionalitues of a product or subsystem is that the context of the solution is known. This paper presents a computer based solution library where...

  1. Radiation dechlorination of PCE in aqueous solutions under various conditions

    International Nuclear Information System (INIS)

    Mucka, V.; Lizalova, B.; Pospisil, M.; Silber, R.; Polakova, D.

    2002-01-01

    Complete text of publication follows. Radiation technology of water purification from chlorinated compounds seems to be one of the promising method (Getoff, 1996), analogously as it was shown (Mueka et al., 2000) with radiation degradation of polychlorinated biphenyls (PCBs). A systematic study of dechlorination of tetrachloroethylene (PCE) in aqueous solutions (initial concentrations ranging from 9.2 x 10 -6 to 2.5 x 10 -4 mol dm -3 ), initiated by γ-rays of 60 Co or by accelerated electrons (EB, 4.5 MeV) in presence of various modifiers (atmospheric oxygen, N 2 O-oxide, HCO 3 - - and NO 3 - - ions as well as various pH-values), was the aim of this paper. The studies showed that both actual concentration c of PCE and radiation yield G(Cl - ) decreased rapidly with increasing dose up to the dose of 2 kGy and the degree of dechlorination raised sharply in this dose-interval. The dechlorination was slightly promoted by atmospheric oxygen. Similarly, a promotion effect was detected in the case of the PCE-solutions saturated, prior to their irradiation, with the N 2 O-oxide. On the other hand, a presence of NO 3 - - or HCO 3 - -ions in irradiated samples led to an inhibiting effect. The inhibiting effect increased markedly with increasing concentration of both at above-mentioned ions up to the concentration of about 100 mg dm -3 . A pronounced inhibition of γ-radiation dechlorination of PCE was observed in alkaline aqueous solutions. The results obtained in this paper support the idea that the radiation dechlorination of PCE in aqueous solutions proceeds via an oxidative mechanism in which the γ-irradiation was found to be more effective than the EB-irradiation

  2. Mobile geographic information system solution for pavement condition surveys [summary].

    Science.gov (United States)

    2012-01-01

    The State Materials Office (SMO) of the Florida : Department of Transportation (FDOT) performs : annual Pavement Condition Surveys (PCS) of : the Departments extensive pavement network. : This work is performed by single-person crews in : inertial...

  3. Existence of weak solutions to first-order stationary mean-field games with Dirichlet conditions

    KAUST Repository

    Ferreira, Rita; Gomes, Diogo A.; Tada, Teruo

    2018-01-01

    In this paper, we study first-order stationary monotone mean-field games (MFGs) with Dirichlet boundary conditions. While for Hamilton--Jacobi equations Dirichlet conditions may not be satisfied, here, we establish the existence of solutions of MFGs that satisfy those conditions. To construct these solutions, we introduce a monotone regularized problem. Applying Schaefer's fixed-point theorem and using the monotonicity of the MFG, we verify that there exists a unique weak solution to the regularized problem. Finally, we take the limit of the solutions of the regularized problem and using Minty's method, we show the existence of weak solutions to the original MFG.

  4. Existence of weak solutions to first-order stationary mean-field games with Dirichlet conditions

    KAUST Repository

    Ferreira, Rita

    2018-04-19

    In this paper, we study first-order stationary monotone mean-field games (MFGs) with Dirichlet boundary conditions. While for Hamilton--Jacobi equations Dirichlet conditions may not be satisfied, here, we establish the existence of solutions of MFGs that satisfy those conditions. To construct these solutions, we introduce a monotone regularized problem. Applying Schaefer\\'s fixed-point theorem and using the monotonicity of the MFG, we verify that there exists a unique weak solution to the regularized problem. Finally, we take the limit of the solutions of the regularized problem and using Minty\\'s method, we show the existence of weak solutions to the original MFG.

  5. On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

    Directory of Open Access Journals (Sweden)

    Appleby JohnAD

    2010-01-01

    Full Text Available We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. The result is considered both for a linear Volterra integrodifferential equation as well as for the delay logistic equation from population biology.

  6. Quantum effects from topological conditions in solutions of Einstein equations

    CERN Document Server

    Patiño, L

    2003-01-01

    In this paper it is shown that Dirac's approach to the quantization of the electric charge can be extended to gravitational configurations by defining a phase-like object related to the curvature of the space-time. Using this phase-like object, Dirac's argument is applied to the Kerr-Newmann and the Taub-NUT solutions to Einstein equations. As a result of this procedure we obtain that certain functions of the parameters entering the metric become quantized. Also, the phase acquired by an observer traveling along a loop around a curvature singularity is quantized. (Author)

  7. Temperature field conduction solution by incomplete boundary condition

    Energy Technology Data Exchange (ETDEWEB)

    Novakovic, M; Petrasinovic, Lj; Djuric, M [Tehnoloski fakultet, Novi Sad (Yugoslavia); Perovic, N [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia)

    1977-01-01

    The problem of determination of one part boundary conditions temperatures for Fourier partial differential equation when the other part of boundary condition and derivates (heat fluxes) are known is a practical interest as it enables one to determine and accessible temperature by measuring temperatures on other side, of the wall. Method developed and applied here consist of transforming the Fourier partial differential equation by time discretisation in sets of pairs of ordinary differential equations for temperature and heat flux. Such pair of differential equations of first order was solved by Runge-Kutta method. The integration proceeds along space interval simultaneosly for all time intervals. It is interesting to note that this procedure does not require the initial condition.

  8. Synthesis of different-sized silver nanoparticles by simply varying reaction conditions with leaf extracts of Bauhinia variegata L.

    Science.gov (United States)

    Kumar, V; Yadav, S K

    2012-03-01

    Green synthesis of nanoparticles is one of the crucial requirements in today's climate change scenario all over the world. In view of this, leaf extract (LE) of Bauhinia variegata L. possessing strong antidiabetic and antibacterial properties has been used to synthesise silver nanoparticles (SNP) in a controlled manner. Various-sized SNP (20-120 nm) were synthesised by varying incubation temperature, silver nitrate and LE concentrations. The rate of SNP synthesis and their size increased with increase in AgNO(3) concentration up to 4 mM. With increase in LE concentration, size and aggregation of SNP was increased. The size and aggregation of SNP were also increased at temperatures above and below 40°C. This has suggested that size and dispersion of SNP can be controlled by varying reaction components and conditions. Polarity-based fractionation of B. variegata LE has suggested that only water-soluble fraction is responsible for SNP synthesis. Fourier transform infrared spectroscopy analysis revealed the attachment of polyphenolic and carbohydrate moieties to SNP. The synthesised SNPs were found stable in double distilled water, BSA and phosphate buffer (pH 7.4). On the contrary, incubation of SNP with NaCl induced aggregation. This suggests the safe use of SNP for various in vivo applications.

  9. Nontrivial Solution of Fractional Differential System Involving Riemann-Stieltjes Integral Condition

    Directory of Open Access Journals (Sweden)

    Ge-Feng Yang

    2012-01-01

    differential system involving the Riemann-Stieltjes integral condition, by using the Leray-Schauder nonlinear alternative and the Banach contraction mapping principle, some sufficient conditions of the existence and uniqueness of a nontrivial solution of a system are obtained.

  10. Varying hydric conditions during incubation influence egg water exchange and hatchling phenotype in the red-eared slider turtle.

    Science.gov (United States)

    Delmas, Virginie; Bonnet, Xavier; Girondot, Marc; Prévot-Julliard, Anne-Caroline

    2008-01-01

    Environmental conditions within the nest, notably temperature and moisture of substrate, exert a powerful influence during embryogenesis in oviparous reptiles. The influence of fluctuating nest temperatures has been experimentally examined in different reptile species; however, similar experiments using moisture as the key variable are lacking. In this article, we examine the effect of various substrate moisture regimes during incubation on different traits (egg mass, incubation length, and hatchling mass) in a chelonian species with flexible-shelled eggs, the red-eared slider turtle (Trachemys scripta elegans). Our results show that the rate of water uptake by the eggs was higher in wet than in dry substrate and varied across development. More important, during the first third of development, the egg mass changes were relatively independent of the soil moisture level; they became very sensitive to moisture levels during the other two-thirds. Moreover, hydric conditions exerted a strong influence on the eggs' long-term sensitivity to the moisture of the substrate. Even short-term episodes of high or low levels of moisture modified permanently their water sensitivity, notably through modification of eggshell shape and volume, and in turn entailed significant effects on hatchling mass (and hence offspring quality). Such complex influences of fluctuating moisture levels at various incubation stages on hatchling phenotype better reflect the natural situation, compared to experiments based on stable, albeit different, moisture levels.

  11. Uranium carbide dissolution in nitric solution: Sonication vs. silent conditions

    International Nuclear Information System (INIS)

    Virot, Matthieu; Szenknect, Stéphanie; Chave, Tony; Dacheux, Nicolas; Moisy, Philippe; Nikitenko, Sergey I.

    2013-01-01

    The dissolution of uranium carbide (UC) in nitric acid media is considered by means of power ultrasound (sonication) or magnetic stirring. The induction period required to initiate UC dissolution was found to be dramatically shortened when sonicating a 3 M nitric solution (Ar, 20 kHz, 18 W cm −2 , 20 °C). At higher acidity, magnetic stirring offers faster dissolution kinetics compared to sonication. Ultrasound-assisted UC dissolution is found to be passivated after ∼60% dissolution and remains incomplete whatever the acidity which is confirmed by ICP–AES, LECO and SEM–EDX analyses. In general, the kinetics of UC dissolution is linked to the in situ generation of nitrous acid in agreement with the general mechanism of UC dissolution; the nitrous acid formation is reported to be faster under ultrasound at low acidity due to the nitric acid sonolysis. The carbon balance shared between the gaseous, liquid, and solid phases is strongly influenced by the applied dissolution procedure and HNO 3 concentration

  12. Uranium carbide dissolution in nitric solution: Sonication vs. silent conditions

    Science.gov (United States)

    Virot, Matthieu; Szenknect, Stéphanie; Chave, Tony; Dacheux, Nicolas; Moisy, Philippe; Nikitenko, Sergey I.

    2013-10-01

    The dissolution of uranium carbide (UC) in nitric acid media is considered by means of power ultrasound (sonication) or magnetic stirring. The induction period required to initiate UC dissolution was found to be dramatically shortened when sonicating a 3 M nitric solution (Ar, 20 kHz, 18 W cm-2, 20 °C). At higher acidity, magnetic stirring offers faster dissolution kinetics compared to sonication. Ultrasound-assisted UC dissolution is found to be passivated after ∼60% dissolution and remains incomplete whatever the acidity which is confirmed by ICP-AES, LECO and SEM-EDX analyses. In general, the kinetics of UC dissolution is linked to the in situ generation of nitrous acid in agreement with the general mechanism of UC dissolution; the nitrous acid formation is reported to be faster under ultrasound at low acidity due to the nitric acid sonolysis. The carbon balance shared between the gaseous, liquid, and solid phases is strongly influenced by the applied dissolution procedure and HNO3 concentration.

  13. Concentrated aqueous sodium chloride solution in clays at thermodynamic conditions of hydraulic fracturing: Insight from molecular dynamics simulations

    Science.gov (United States)

    Svoboda, Martin; Lísal, Martin

    2018-06-01

    To address a high salinity of flow-back water during hydraulic fracturing, we use molecular dynamics (MD) simulations and study the thermodynamics, structure, and diffusion of concentrated aqueous salt solution in clay nanopores. The concentrated solution results from the dissolution of a cubic NaCl nanocrystal, immersed in an aqueous NaCl solution of varying salt concentration and confined in clay pores of a width comparable to the crystal size. The size of the nanocrystal equals to about 18 Å which is above a critical nucleus size. We consider a typical shale gas reservoir condition of 365 K and 275 bar, and we represent the clay pores as pyrophyllite and Na-montmorillonite (Na-MMT) slits. We employ the Extended Simple Point Charge (SPC/E) model for water, Joung-Cheatham model for ions, and CLAYFF for the slit walls. We impose the pressure in the normal direction and the resulting slit width varies from about 20 to 25 Å when the salt concentration in the surrounding solution increased from zero to an oversaturated value. By varying the salt concentration, we observe two scenarios. First, the crystal dissolves and its dissolution time increases with increasing salt concentration. We describe the dissolution process in terms of the number of ions in the crystal, and the crystal size and shape. Second, when the salt concentration reaches a system solubility limit, the crystal grows and attains a new equilibrium size; the crystal comes into equilibrium with the surrounding saturated solution. After crystal dissolution, we carry out canonical MD simulations for the concentrated solution. We evaluate the hydration energy, density profiles, orientation distributions, hydrogen-bond network, radial distribution functions, and in-plane diffusion of water and ions to provide insight into the microscopic behaviour of the concentrated aqueous sodium chloride solution in interlayer galleries of the slightly hydrophobic pyrophyllite and hydrophilic Na-MMT pores.

  14. Experiments and numerical modeling of fast flowing liquid metal thin films under spatially varying magnetic field conditions

    Science.gov (United States)

    Narula, Manmeet Singh

    Innovative concepts using fast flowing thin films of liquid metals (like lithium) have been proposed for the protection of the divertor surface in magnetic fusion devices. However, concerns exist about the possibility of establishing the required flow of liquid metal thin films because of the presence of strong magnetic fields which can cause flow disrupting MHD effects. A plan is underway to design liquid lithium based divertor protection concepts for NSTX, a small spherical torus experiment at Princeton. Of these, a promising concept is the use of modularized fast flowing liquid lithium film zones, as the divertor (called the NSTX liquid surface module concept or NSTX LSM). The dynamic response of the liquid metal film flow in a spatially varying magnetic field configuration is still unknown and it is suspected that some unpredicted effects might be lurking. The primary goal of the research work being reported in this dissertation is to provide qualitative and quantitative information on the liquid metal film flow dynamics under spatially varying magnetic field conditions, typical of the divertor region of a magnetic fusion device. The liquid metal film flow dynamics have been studied through a synergic experimental and numerical modeling effort. The Magneto Thermofluid Omnibus Research (MTOR) facility at UCLA has been used to design several experiments to study the MHD interaction of liquid gallium films under a scaled NSTX outboard divertor magnetic field environment. A 3D multi-material, free surface MHD modeling capability is under development in collaboration with HyPerComp Inc., an SBIR vendor. This numerical code called HIMAG provides a unique capability to model the equations of incompressible MHD with a free surface. Some parts of this modeling capability have been developed in this research work, in the form of subroutines for HIMAG. Extensive code debugging and benchmarking exercise has also been carried out. Finally, HIMAG has been used to study the

  15. Scale-invariant solutions to partial differential equations of fractional order with a moving boundary condition

    International Nuclear Information System (INIS)

    Li Xicheng; Xu Mingyu; Wang Shaowei

    2008-01-01

    In this paper, we give similarity solutions of partial differential equations of fractional order with a moving boundary condition. The solutions are given in terms of a generalized Wright function. The time-fractional Caputo derivative and two types of space-fractional derivatives are considered. The scale-invariant variable and the form of the solution of the moving boundary are obtained by the Lie group analysis. A comparison between the solutions corresponding to two types of fractional derivative is also given

  16. Analytical Solution of the Schrödinger Equation with Spatially Varying Effective Mass for Generalised Hylleraas Potential

    International Nuclear Information System (INIS)

    Debnath, S.; Maji, Smarajit; Meyur, Sanjib

    2014-01-01

    We have obtained exact solution of the effective mass Schrödinger equation for the generalised Hylleraas potential. The exact bound state energy eigenvalues and corresponding eigenfunctions are presented. The bound state eigenfunctions are obtained in terms of the hypergeometric functions. Results are also given for the special case of potential parameter.

  17. Impact of Varying Wave Conditions on the Mobility of Arsenic in a Nearshore Aquifer on the Great Lakes

    Science.gov (United States)

    Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

    2017-12-01

    Groundwater-coastal water interactions play an important role in controlling the behavior of inorganic chemicals in nearshore aquifers and the subsequent flux of these chemicals to receiving coastal waters. Previous studies have shown that dynamic groundwater flows and water exchange across the sediment-water interface can set up strong geochemical gradients and an important reaction zone in a nearshore aquifer that affect the fate of reactive chemicals. There is limited understanding of the impact of transient coastal forcing such as wave conditions on groundwater dynamics and geochemistry in a nearshore aquifer. The goal of this study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer and to determine the hydrological and geochemical factors controlling its fate and ultimate delivery to receiving coastal waters. Field investigations were conducted over the period of intensified wave conditions on a freshwater beach on Lake Erie, Canada. High spatial resolution aqueous and sediment sampling was conducted to characterize the subsurface distribution of inorganic species in the nearshore aquifer. Numerical groundwater flow and transport simulations were conducted to evaluate wave-induced perturbations in the flow dynamics including characterizing changes in the groundwater flow recirculations in the nearshore aquifer. The combination of field data and numerical simulations reveal that varying wave conditions alter groundwater flows and set up geochemical transition zones within the aquifer resulting in the release and sequestration of arsenic. Interactions between oxic surface water, mildly reducing shallow groundwater, and reducing sulfur- and iron-rich deep groundwater promote dynamic iron, sulfur and manganese cycling which control the mobility of arsenic in the aquifer. The findings of this study have potential implications for the fate and transport of other reactive chemicals (e.g. phosphorus, mercury) in

  18. Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity

    Directory of Open Access Journals (Sweden)

    Katarzyna Majchrzycka

    2016-01-01

    Full Text Available Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs. Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%–92% and temperature increased to 29–30 °C. S. aureus survived the best on filter materials with 40%–200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48–72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

  19. Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity.

    Science.gov (United States)

    Majchrzycka, Katarzyna; Okrasa, Małgorzata; Skóra, Justyna; Gutarowska, Beata

    2016-01-04

    Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs). Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%-92% and temperature increased to 29-30 °C. S. aureus survived the best on filter materials with 40%-200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48-72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

  20. X-ray CT-Derived Soil Characteristics Explain Varying Air, Water, and Solute Transport Properties across a Loamy Field

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

    2016-01-01

    -derived parameters by using a best subsets regression analysis. The regression coefficients improved using CTmatrix, limiting macroporosity, and genus density, while the best model for t0.05 used CTmatrix only. The scanning resolution and the time for soil structure development after mechanical activities could......The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with measurements...

  1. Bifurcation of positive solutions to scalar reaction-diffusion equations with nonlinear boundary condition

    Science.gov (United States)

    Liu, Ping; Shi, Junping

    2018-01-01

    The bifurcation of non-trivial steady state solutions of a scalar reaction-diffusion equation with nonlinear boundary conditions is considered using several new abstract bifurcation theorems. The existence and stability of positive steady state solutions are proved using a unified approach. The general results are applied to a Laplace equation with nonlinear boundary condition and bistable nonlinearity, and an elliptic equation with superlinear nonlinearity and sublinear boundary conditions.

  2. Relationship between continuity of care and adverse outcomes varies by number of chronic conditions among older adults with diabetes

    Directory of Open Access Journals (Sweden)

    Eva H. DuGoff

    2016-06-01

    Full Text Available Follow us on Twitter Co-Editors-in-Chief Martin Fortin Jane Gunn Stewart W. Mercer Susan Smith Marjan van den Akker Society for Academic Primary Care Journal Help USER You are logged in as... avalster My Profile Log Out JOURNAL CONTENT Search Search Scope Search Browse By Issue By Author By Title By Sections By Identify Types OPEN JOURNAL SYSTEMS FONT SIZE Make font size smallerMake font size defaultMake font size larger INFORMATION For Readers For Authors For Librarians ARTICLE TOOLS Print this article Indexing metadata How to cite item Supplementary files Finding References Email this article Email the author Post a Comment NOTIFICATIONS View (378 new Manage IRCMO NEWS ‘Addressing the global challenge of... Publications on multimorbidity... The CARE Plus study Prevalence of multimorbidity in the... Multimorbidity in adults from a... CURRENT ISSUE Atom logo RSS2 logo RSS1 logo HOSTED BY Part of the PKP Publishing Services Network HOME ABOUT USER HOME SEARCH CURRENT ARCHIVES ANNOUNCEMENTS PUBLISHER AUTHOR GUIDELINES SUBMISSIONS WHY PUBLISH WITH US? Home > Vol 6, No 2 (2016 >\tDuGoff Relationship between continuity of care and adverse outcomes varies by number of chronic conditions among older adults with diabetes Eva H. DuGoff, Karen Bandeen-Roche, Gerard F. Anderson Abstract Background: Continuity of care is a basic tenant of primary care practice. However, the evidence on the importance of continuity of care for older adults with complex conditions is mixed. Objective: To assess the relationship between measurement of continuity of care, number of chronic conditions, and health outcomes. Design: We analyzed data from a cohort of 1,600 US older adults with diabetes and ≥1 other chronic condition in a private Medicare health plan from July 2010 to December 2011. Multivariate regression models were used to examine the association of baseline continuity (the first 6 months and the composite outcome of any emergency room use or inpatient

  3. Solution of Einstein's Geometrical Gravitational Field Equations Exterior to Astrophysically Real or Hypothetical Time Varying Distributions of Mass within Regions of Spherical Geometry

    Directory of Open Access Journals (Sweden)

    Chifu E. N.

    2009-07-01

    Full Text Available Here, we present a profound and complete analytical solution to Einstein’s gravitational field equations exterior to astrophysically real or hypothetical time varying distribu- tions of mass or pressure within regions of spherical geometry. The single arbitrary function f in our proposed exterior metric tensor and constructed field equations makes our method unique, mathematically less combersome and astrophysically satisfactory. The obtained solution of Einstein’s gravitational field equations tends out to be a gen- eralization of Newton’s gravitational scalar potential exterior to the spherical mass or pressure distribution under consideration

  4. Reaction kinetics of hydrazine neutralization in steam generator wet lay-up solution: Identifying optimal degradation conditions

    International Nuclear Information System (INIS)

    Schildermans, Kim; Lecocq, Raphael; Girasa, Emmanuel

    2012-09-01

    During a nuclear power plant outage, hydrazine is used as an oxygen scavenger in the steam generator lay-up solution. However, due to the carcinogenic effects of hydrazine, more stringent discharge limits are or will be imposed in the environmental permits. Hydrazine discharge could even be prohibited. Consequently, hydrazine alternatives or hydrazine degradation before discharge is needed. This paper presents the laboratory tests performed to characterize the reaction kinetics of hydrazine neutralization using bleach or hydrogen peroxide, catalyzed with either copper sulfate (CuSO 4 ) or potassium permanganate (KMnO 4 ). The tests are performed on two standard steam generator lay-up solutions based on different pH control agents: ammonia or ethanolamine. Different neutralization conditions are tested by varying temperature, oxidant addition, and catalyst concentration, among others, in order to identify the optimal parameters for hydrazine neutralization in a steam generator wet lay-up solution. (authors)

  5. Exploring Heterogeneous and Time-Varying Materials for Photonic Applications, Towards Solutions for the Manipulation and Confinement of Light.

    KAUST Repository

    San Roman Alerigi, Damian

    2014-01-01

    Over the past several decades our understanding and meticulous characterization of the transient and spatial properties of materials evolved rapidly. The results present an exciting field for discovery, and craft materials to control and reshape light that we are just beginning to fathom. State-of-the-art nano-deposition processes, for example, can be utilized to build stratified waveguides made of thin dielectric layers, which put together result in a material with effective abnormal dispersion. Moreover, materials once deemed well known are revealing astonishing properties, v.gr. chalcogenide glasses undergo an atomic reconfiguration when illuminated with electrons or photons, this ensues in a temporal modification of its permittivity and permeability which could be used to build new Photonic Integrated Circuits.. This work revolves around the characterization and model of heterogeneous and time-varying materials and their applications, revisits Maxwell's equations in the context of nonlinear space- and time-varying media, and based on it introduces a numerical scheme that can be used to model waves in this kind of media. Finally some interesting applications for light confinement and beam transformations are shown.

  6. Exploring Heterogeneous and Time-Varying Materials for Photonic Applications, Towards Solutions for the Manipulation and Confinement of Light.

    KAUST Repository

    San Roman Alerigi, Damian

    2014-11-01

    Over the past several decades our understanding and meticulous characterization of the transient and spatial properties of materials evolved rapidly. The results present an exciting field for discovery, and craft materials to control and reshape light that we are just beginning to fathom. State-of-the-art nano-deposition processes, for example, can be utilized to build stratified waveguides made of thin dielectric layers, which put together result in a material with effective abnormal dispersion. Moreover, materials once deemed well known are revealing astonishing properties, v.gr. chalcogenide glasses undergo an atomic reconfiguration when illuminated with electrons or photons, this ensues in a temporal modification of its permittivity and permeability which could be used to build new Photonic Integrated Circuits.. This work revolves around the characterization and model of heterogeneous and time-varying materials and their applications, revisits Maxwell\\'s equations in the context of nonlinear space- and time-varying media, and based on it introduces a numerical scheme that can be used to model waves in this kind of media. Finally some interesting applications for light confinement and beam transformations are shown.

  7. The analytical solution for drug delivery system with nonhomogeneous moving boundary condition

    Science.gov (United States)

    Saudi, Muhamad Hakimi; Mahali, Shalela Mohd; Harun, Fatimah Noor

    2017-08-01

    This paper discusses the development and the analytical solution of a mathematical model based on drug release system from a swelling delivery device. The mathematical model is represented by a one-dimensional advection-diffusion equation with nonhomogeneous moving boundary condition. The solution procedures consist of three major steps. Firstly, the application of steady state solution method, which is used to transform the nonhomogeneous moving boundary condition to homogeneous boundary condition. Secondly, the application of the Landau transformation technique that gives a significant impact in removing the advection term in the system of equation and transforming the moving boundary condition to a fixed boundary condition. Thirdly, the used of separation of variables method to find the analytical solution for the resulted initial boundary value problem. The results show that the swelling rate of delivery device and drug release rate is influenced by value of growth factor r.

  8. Heavy metals in precipitation waters under conditions of varied anthropopressure in typical of European low mountain regions

    Directory of Open Access Journals (Sweden)

    Rabajczyk A.

    2013-04-01

    Full Text Available The environment is a dynamic system, subject to change resulting from a variety of physicochemical factors, such as temperature, pressure, pH, redox potential and human activity. The quantity and variety of these determinants cause the inflow of substances into individual environmental elements to vary in both time and space, as well as in terms of substance types and quantities. The energy and matter flow in the environment determines its integrity, which means that the processes occurring in one element of the environment affect the others. A certain measure of the energy and matter flow is the migration of chemical substances in various forms from one place to another. In a particular geographical space, under natural conditions, a specific level of balance between individual processes appears; in areas subject to anthropopressure, the correlations are different. In small areas, varying deposition volumes and chemism of precipitation waters which reach the substratum directly can both be observed. The study area is similar in terms of geological origins as well as morphological, structural and physico-chemical properties, and is typical of European low mountain regions. A qualitative and quantitative study of wet atmospheric precipitation was conducted between February 2009 and May 2011 in the Bobrza river catchment in the Holy Cross (Świętokrzyskie Mountains (Poland, at three sampling sites of varying land development and distance from sources of various acidic-alkaline emissions. Field and laboratory work was conducted over 29 months, from February 2009 to May 2011. Atmospheric precipitation measurements were carried out in a continuous manner by means of a Hellman rain gauge (200cm2. The collecting surface was placed at ground level (0m AGL. The application of a collecting funnel and an adequately prepared polyethylene collecting can in the rain gauge enabled the measurement of precipitation volume and water sampling for chemical

  9. The exact solution to the one-dimensional Poisson–Boltzmann equation with asymmetric boundary conditions

    DEFF Research Database (Denmark)

    Johannessen, Kim

    2014-01-01

    The exact solution to the one-dimensional Poisson–Boltzmann equation with asymmetric boundary conditions can be expressed in terms of the Jacobi elliptic functions. The boundary conditions determine the modulus of the Jacobi elliptic functions. The boundary conditions can not be solved analytically...

  10. The Effect of Varying Ultrafast Pulse Laser Energies on the Electrical Properties of Reduced Graphene Oxide Sheets in Solution

    Science.gov (United States)

    Ibrahim, Khaled H.; Irannejad, Mehrdad; Wales, Benjamin; Sanderson, Joseph; Musselman, Kevin P.; Yavuz, Mustafa

    2018-02-01

    Laser treatment of graphene oxide solution among other techniques is a well-established technique for producing reduced graphene sheets. However, production of high-quality ultra-low sheet resistance reduced graphene oxide (rGO) sheets in solution has been a challenge due to their high degree of randomness, defect-rich medium, and lack of controlability. Recent studies lack an in-depth analytic comparison of laser treatment parameters that yield the highest quality rGO sheets with a low defect ratio. Hence, in this study, we implement a comprehensive comparison of laser treatment parameters and their effect on the yielded rGO sheets from an electronic and physical standpoint. Ultra-low sheet resistance graphene oxide sheets were fabricated using ultrafast laser irradiation with different laser pulse energies in the range of 0.25-2 mJ. Laser treatment for 10 min using a pulse energy of 1 mJ resulted in an increase in the defect spacing, accompanied by a large red shift in the optical absorption of the C=C bond, indicating significant restoration of the s p 2 carbon bonds. These enhancements resulted in a significant reduction in the electrical resistance of the rGO flakes (up to 2 orders of magnitude), raising the electron mobility of the films produced using the irradiated graphene oxide a step closer to that of pristine graphene films. From this study, we can also deduce which exposure regimes result in the fabrication of quantum dots and continuous defect-free films.

  11. Positive solutions of nonlinear fractional boundary value problems with Dirichlet boundary conditions

    Directory of Open Access Journals (Sweden)

    Qingkai Kong

    2012-02-01

    Full Text Available In this paper, we study the existence and multiplicity of positive solutions of a class of nonlinear fractional boundary value problems with  Dirichlet boundary conditions. By applying the fixed point theory on cones we establish a series of criteria for the existence of one, two, any arbitrary finite number, and an infinite number of positive solutions. A criterion for the nonexistence of positive solutions is also derived. Several examples are given for demonstration.

  12. Breather type solutions of the vector nonlinear Schroedinger equation with quasi-constant boundary conditions

    International Nuclear Information System (INIS)

    Makhan'kov, V.G.; Slavov, S.I.

    1989-01-01

    Vector nonlinear Schroedinger equations (VS3) is investigated under quasi-constant boundary conditions. New two-soliton solutions are obtained with such non-trivial dynamics that they may be called the breather solutions. A version of the basic Novikov-Dubrovin-Krichever algebro-geometrical approach is applied to obtain breather like solutions existing for all types of internal symmetry is specified are formulated in terms of the soliton velocity expressed via the parameters of the problem. 4 refs

  13. Existence of Solutions of Abstract Nonlinear Mixed Functional Integrodifferential equation with nonlocal conditions

    Directory of Open Access Journals (Sweden)

    Dhakne Machindra B.

    2017-04-01

    Full Text Available In this paper we discuss the existence of mild and strong solutions of abstract nonlinear mixed functional integrodifferential equation with nonlocal condition by using Sadovskii’s fixed point theorem and theory of fractional power of operators.

  14. Varied Human Tolerance to the Combined Conditions of Low Contrast and Diminished Luminance: A Quasi-Meta Analysis

    Science.gov (United States)

    2017-08-30

    conditions (e.g., dry eyes , mild cataractous conditions, Stevens-Johnson Syndrome ) using CS alone as the performance index. More commonly, it has been...subjects tested under conditions of spherical blur, astigmatic blur, low luminance, and one eye vs. two eyes ...conditions). The vast majority of past mesopic visual performance studies were predominantly isolated to evaluations of various eye disease

  15. On the physical solutions to the heat equation subjected to nonlinear boundary conditions

    International Nuclear Information System (INIS)

    Gama, R.M.S. da.

    1990-01-01

    This work consists of a discussion on the physical solutions to the steady-state heat transfer equation, when it is subjected to nonlinear boundary conditions. It will be presented a functional, whose minimum occurs for the (unique) physical solution to the condidered heat transfer problem, suitable for a large class of typical (nonlinear) boundary conditions (representing the radiative/convective loss from the body to the environment). It will be demonstrated that these problems admit-always one, and only one, physical solution (which represents the absolute temperature). (author)

  16. Recursive solution for dynamic response of one-dimensional structures with time-dependent boundary conditions

    International Nuclear Information System (INIS)

    Abadi, Mohammad Tahaye

    2015-01-01

    A recursive solution method is derived for the transient response of one-dimensional structures subjected to the general form of time dependent boundary conditions. Unlike previous solution methods that assumed the separation of variables, the present method involves formulating and solving the dynamic problems using the summation of two single-argument functions satisfying the motion equation. Based on boundary and initial conditions, a recursive procedure is derived to determine the single-argument functions. Such a procedure is applied to the general form of boundary conditions, and an analytical solution is derived by solving the recursive equation. The present solution method is implemented for base excitation problems, and the results are compared with those of the previous analytical solution and the Finite element (FE) analysis. The FE results converge to the present analytical solution, although considerable error is found in predicting a solution method on the basis of the separation of variables. The present analytical solution predicts the transient response for wave propagation problems in broadband excitation frequencies.

  17. Recursive solution for dynamic response of one-dimensional structures with time-dependent boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Abadi, Mohammad Tahaye [Aerospace Research Institute, Tehran (Iran, Islamic Republic of)

    2015-10-15

    A recursive solution method is derived for the transient response of one-dimensional structures subjected to the general form of time dependent boundary conditions. Unlike previous solution methods that assumed the separation of variables, the present method involves formulating and solving the dynamic problems using the summation of two single-argument functions satisfying the motion equation. Based on boundary and initial conditions, a recursive procedure is derived to determine the single-argument functions. Such a procedure is applied to the general form of boundary conditions, and an analytical solution is derived by solving the recursive equation. The present solution method is implemented for base excitation problems, and the results are compared with those of the previous analytical solution and the Finite element (FE) analysis. The FE results converge to the present analytical solution, although considerable error is found in predicting a solution method on the basis of the separation of variables. The present analytical solution predicts the transient response for wave propagation problems in broadband excitation frequencies.

  18. Legendre condition and the stabilization problem for classical soliton solutions in generalized Skyrme models

    International Nuclear Information System (INIS)

    Kiknadze, N.A.; Khelashvili, A.A.

    1990-01-01

    The problem on stability of classical soliton solutions is studied from the unique point of view: the Legendre condition - necessary condition of existence of weak local minimum for energy functional (term soliton is used here in the wide sense) is used. Limits to parameters of the model Lagrangians are obtained; it is shown that there is no soliton stabilization in some of them despite the phenomenological achievements. The Jacoby sufficient condition is discussed

  19. Variation formulae for the solutions of delay differential equations with discontinuous initial conditions

    International Nuclear Information System (INIS)

    Kharatishvili, G L; Tadumadze, T A

    2005-01-01

    Variation formulae are proved for solutions of non-linear differential equations with variable delays and discontinuous initial conditions. The discontinuity of the initial condition means that at the initial moment of time the values of the initial function and the trajectory, generally speaking, do not coincide. The formulae obtained contain a new summand connected with the discontinuity of the initial condition and the variation of the initial moment.

  20. Exact solution for four-order acousto-optic Bragg diffraction with arbitrary initial conditions.

    Science.gov (United States)

    Pieper, Ron; Koslover, Deborah; Poon, Ting-Chung

    2009-03-01

    An exact solution to the four-order acousto-optic (AO) Bragg diffraction problem with arbitrary initial conditions compatible with exact Bragg angle incident light is developed. The solution, obtained by solving a 4th-order differential equation, is formalized into a transition matrix operator predicting diffracted light orders at the exit of the AO cell in terms of the same diffracted light orders at the entrance. It is shown that the transition matrix is unitary and that this unitary matrix condition is sufficient to guarantee energy conservation. A comparison of analytical solutions with numerical predictions validates the formalism. Although not directly related to the approach used to obtain the solution, it was discovered that all four generated eigenvalues from the four-order AO differential matrix operator are expressed simply in terms of Euclid's Divine Proportion.

  1. γ-Radiolysis of benzophenone aqueous solution at elevated temperatures up to supercritical condition

    International Nuclear Information System (INIS)

    Miyazaki, Toyoaki; Katsumura, Yosuke; Lin Mingzhang; Muroya, Yusa; Kudo, Hisaaki; Asano, Masaharu; Yoshida, Masaru

    2006-01-01

    A product analysis study of γ-irradiated benzophenone aqueous solutions from room temperature to 400 deg. C has been carried out by the combination of a flow irradiation system and a liquid chromatographic method. At room temperature, the main decomposition products are phenol and hydroxybenzophenone isomers. In high temperature and supercritical water solutions, 9-fluorenone appears as an important product and the G-value of benzophenone consumption depends significantly on the water density under supercritical conditions

  2. Existence of mild solutions of a semilinear evolution differential inclusions with nonlocal conditions

    Directory of Open Access Journals (Sweden)

    Reem A. Al-Omair

    2009-03-01

    Full Text Available In this paper we prove the existence of a mild solution for a semilinear evolution differential inclusion with nonlocal condition and governed by a family of linear operators, not necessarily bounded or closed, in a Banach space. No compactness assumption is assumed on the evolution operator generated by the family operators. Also, we prove that the set of mild solutions is compact.

  3. Analytical solutions for coupling fractional partial differential equations with Dirichlet boundary conditions

    Science.gov (United States)

    Ding, Xiao-Li; Nieto, Juan J.

    2017-11-01

    In this paper, we consider the analytical solutions of coupling fractional partial differential equations (FPDEs) with Dirichlet boundary conditions on a finite domain. Firstly, the method of successive approximations is used to obtain the analytical solutions of coupling multi-term time fractional ordinary differential equations. Then, the technique of spectral representation of the fractional Laplacian operator is used to convert the coupling FPDEs to the coupling multi-term time fractional ordinary differential equations. By applying the obtained analytical solutions to the resulting multi-term time fractional ordinary differential equations, the desired analytical solutions of the coupling FPDEs are given. Our results are applied to derive the analytical solutions of some special cases to demonstrate their applicability.

  4. Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Paz, M.G., E-mail: myrnasandoval@udec.cl [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Rodríguez, C.A. [Department of Materials Engineering, Faculty of Engineering, University of Concepción, Edmundo Larenas 270, Concepción 4070409 (Chile); Porcile-Saavedra, P.F. [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Trejo-Cruz, C. [Department of Physics, Faculty of Science, University of Biobío, Avenue Collao 1202, Box 5C, Concepción 4051381 (Chile)

    2016-07-15

    Copper (I) selenide thin films with orthorhombic and cubic structure were deposited on glass substrates by using the chemical bath deposition technique. The effects of the solution pH on the films growth and subsequently the structural, optical and electrical properties of the films were studied. Films with orthorhombic structure were obtained from baths wherein both metal complex and hydroxide coexist; while films with cubic structure were obtained from baths where the metal hydroxide there is no present. The structural modifications are accompanied by changes in bandgap energy, morphology and electrical resistivity of the films. - Graphical abstract: “Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution” by M. G. Sandoval-Paz, C. A. Rodríguez, P. F. Porcile-Saavedra, C. Trejo-Cruz. Display Omitted - Highlights: • Copper (I) selenide thin films were obtained by chemical bath deposition. • Orthorhombic to cubic phase change was induced by varying the reaction solution pH. • Orthorhombic phase is obtained mainly from a hydroxides cluster mechanism. • Cubic phase is obtained mainly from an ion by ion mechanism. • Structural, optical and electrical properties are presented as a function of pH.

  5. The Effects of Electroless Nickel Plating Bath Conditions on Stability of Solution and Properties of Deposit

    International Nuclear Information System (INIS)

    Huh, Jin; Lee, Jae Ho

    2000-01-01

    Electroless depositions of nickel were conducted in different bath conditions to find optimum conditions of electroless nickel plating at low operating temperature and pH. The effect of complexing reagent on stability of plating solution was investigated. Sodium citrate complexed plating solution is more stable than sodium pyrophosphate complexed solution. The effects of nickel salt concentration, reducing agent, complexing agent and inhibitor on deposition rate was investigated. The effects of pH on deposition rate and content of phosphorous in deposited nickel were also analyzed. Electroless deposited nickel become crystallized with increasing pH due to lower phosphorous content. In optimum operating bath condition, deposition rate was 7 μm/hr at 60 .deg. C and pH 10.0 without stabilizer. The rate was decreased with stabilizer concentration

  6. Preconditioned characteristic boundary conditions based on artificial compressibility method for solution of incompressible flows

    Science.gov (United States)

    Hejranfar, Kazem; Parseh, Kaveh

    2017-09-01

    The preconditioned characteristic boundary conditions based on the artificial compressibility (AC) method are implemented at artificial boundaries for the solution of two- and three-dimensional incompressible viscous flows in the generalized curvilinear coordinates. The compatibility equations and the corresponding characteristic variables (or the Riemann invariants) are mathematically derived and then applied as suitable boundary conditions in a high-order accurate incompressible flow solver. The spatial discretization of the resulting system of equations is carried out by the fourth-order compact finite-difference (FD) scheme. In the preconditioning applied here, the value of AC parameter in the flow field and also at the far-field boundary is automatically calculated based on the local flow conditions to enhance the robustness and performance of the solution algorithm. The code is fully parallelized using the Concurrency Runtime standard and Parallel Patterns Library (PPL) and its performance on a multi-core CPU is analyzed. The incompressible viscous flows around a 2-D circular cylinder, a 2-D NACA0012 airfoil and also a 3-D wavy cylinder are simulated and the accuracy and performance of the preconditioned characteristic boundary conditions applied at the far-field boundaries are evaluated in comparison to the simplified boundary conditions and the non-preconditioned characteristic boundary conditions. It is indicated that the preconditioned characteristic boundary conditions considerably improve the convergence rate of the solution of incompressible flows compared to the other boundary conditions and the computational costs are significantly decreased.

  7. Generation of synthetic surface electromyography signals under fatigue conditions for varying force inputs using feedback control algorithm.

    Science.gov (United States)

    Venugopal, G; Deepak, P; Ghosh, Diptasree M; Ramakrishnan, S

    2017-11-01

    Surface electromyography is a non-invasive technique used for recording the electrical activity of neuromuscular systems. These signals are random, complex and multi-component. There are several techniques to extract information about the force exerted by muscles during any activity. This work attempts to generate surface electromyography signals for various magnitudes of force under isometric non-fatigue and fatigue conditions using a feedback model. The model is based on existing current distribution, volume conductor relations, the feedback control algorithm for rate coding and generation of firing pattern. The result shows that synthetic surface electromyography signals are highly complex in both non-fatigue and fatigue conditions. Furthermore, surface electromyography signals have higher amplitude and lower frequency under fatigue condition. This model can be used to study the influence of various signal parameters under fatigue and non-fatigue conditions.

  8. A SVDD and K-Means Based Early Warning Method for Dual-Rotor Equipment under Time-Varying Operating Conditions

    Directory of Open Access Journals (Sweden)

    Zhinong Jiang

    2018-01-01

    Full Text Available Under frequently time-varying operating conditions, equipment with dual rotors like gas turbines is influenced by two rotors with different rotating speeds. Alarm methods of fixed threshold are unable to consider the influences of time-varying operating conditions. Hence, those methods are not suitable for monitoring dual-rotor equipment. An early warning method for dual-rotor equipment under time-varying operating conditions is proposed in this paper. The influences of time-varying rotating speeds of dual rotors on alarm thresholds have been considered. Firstly, the operating conditions are divided into several limited intervals according to rotating speeds of dual rotors. Secondly, the train data within each interval is processed by SVDD and the allowable ranges (i.e., the alarm threshold of the vibration are determined. The alarm threshold of each interval of operating conditions is obtained. The alarm threshold can be expressed as a sphere, whose controlling parameters are the coordinate of the center and the radius. Then, the cluster center of the test data, whose alarm state is to be judged, can be extracted through K-means. Finally, the alarm state can be obtained by comparing the cluster center with the corresponding sphere. Experiments are conducted to validate the proposed method.

  9. Biodiesel production process optimization and characterization to assess the suitability of the product for varied environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Eevera, T.; Rajendran, K.; Saradha, S. [Department of Biotechnology, Periyar Maniammai University, Periyar Nagar, Vallam, Thanjavur, Tamilnadu 613 403 (India)

    2009-03-15

    In this study, both edible (coconut oil, palm oil, groundnut oil, and rice bran oil) and non-edible oils (pongamia, neem and cotton seed oil) were used to optimize the biodiesel production process variables like catalyst concentration, amount of methanol required for reaction, reaction time and reaction temperature. The fuel properties like specific gravity, moisture content, refractive index, acid value, iodine number, saponification value and peroxide value were estimated. Based on the cetane number and iodine value, the methyl esters obtained from palm and coconut oils were not suitable to use as biodiesel in cold weather conditions, but for hot climate condition biodiesel obtained from the remaining oil sources is suitable. (author)

  10. TRANSFORMATION OF PB(II FROM CERRUSITE TO CHLOROPYROMORPHITE IN THE PRESENCE OF HYDROXYAPATITE UNDER VARYING CONDITIONS OF PH

    Science.gov (United States)

    The soluble Pb concentration and formation of chloropyromorphite [Pb5(PO4)3Cl] were monitored during the reaction of cerrusite (PbCO3), a highly bioavailable soil Pb species, and hydroxyapatite [Ca5(PO4)3OH] at various P/Pb molar ratios under constant and dynamic pH conditions. ...

  11. Foam Core Particleboards with Intumescent FRT Veneer: Cone Calorimeter Testing With Varying Adhesives, Surface Layer Thicknesses, and Processing Conditions

    Science.gov (United States)

    Mark A. Dietenberger; Johannes Welling; Ali Shalbafan

    2014-01-01

    Intumescent FRT Veneers adhered to the surface of foam core particleboard to provide adequate fire protection were evaluated by means of cone calorimeter tests (ASTM E1354). The foam core particleboards were prepared with variations in surface layer treatment, adhesives, surface layer thicknesses, and processing conditions. Ignitability, heat release rate profile, peak...

  12. Development of integrated radioactive waste packaging and conditioning solutions in the UK

    Energy Technology Data Exchange (ETDEWEB)

    Sibley, Peter; Butter, Kevin; Zimmerman, Ian [EnergySolutions EU Ltd., Swindon, Wiltshire (United Kingdom); Viermann, Joerg [GNS Gesellschaft fur Nuklear-Service mbH, Essen (Germany); Messer, Matthias [GNS Gesellschaft fur Nuklear-Service mbH, Bristol (United Kingdom)

    2013-07-01

    In order to offer a more cost effective, safer and efficient Intermediate Level Waste (ILW) management service, EnergySolutions EU Ltd. and Gesellschaft fur Nuklear-Service mbH (GNS) have been engaged in the development of integrated radioactive waste retrieval, packaging and conditioning solutions in the UK. Recognising the challenges surrounding regulatory endorsement and on-site implementation in particular, this has resulted in an alternative approach to meeting customer, safety regulator and disposability requirements. By working closely with waste producers and the organisation(s) responsible for endorsing radioactive waste management operations in the UK, our proposed solutions are now being implemented. By combining GNS' off-the-shelf, proven Ductile Cast Iron Containers (DCICs) and water removal technologies, with EnergySolutions EU Ltd.'s experience and expertise in waste retrieval, safety case development and disposability submissions, a fully integrated service offering has been developed. This has involved significant effort to overcome technical challenges such as onsite equipment deployment, active commissioning, conditioning success criteria and disposability acceptance. Our experience in developing such integrated solutions has highlighted the importance of working in collaboration with all parties to achieve a successful and viable outcome. Ultimately, the goal is to ensure reliable, safe and effective delivery of waste management solutions. (authors)

  13. Exact Solutions of a High-Order Nonlinear Wave Equation of Korteweg-de Vries Type under Newly Solvable Conditions

    Directory of Open Access Journals (Sweden)

    Weiguo Rui

    2014-01-01

    Full Text Available By using the integral bifurcation method together with factoring technique, we study a water wave model, a high-order nonlinear wave equation of KdV type under some newly solvable conditions. Based on our previous research works, some exact traveling wave solutions such as broken-soliton solutions, periodic wave solutions of blow-up type, smooth solitary wave solutions, and nonsmooth peakon solutions within more extensive parameter ranges are obtained. In particular, a series of smooth solitary wave solutions and nonsmooth peakon solutions are obtained. In order to show the properties of these exact solutions visually, we plot the graphs of some representative traveling wave solutions.

  14. Differential Effect of Solution Conditions on the Conformation of the Actinoporins Sticholysin II and Equinatoxin II

    Directory of Open Access Journals (Sweden)

    EDSON V.F. FAUTH

    2014-12-01

    Full Text Available Actinoporins are a family of pore-forming proteins with hemolytic activity. The structural basis for such activity appears to depend on their correct folding. Such folding encompasses a phosphocholine binding site, a tryptophan-rich region and the activity-related N-terminus segment. Additionally, different solution conditions are known to be able to influence the pore formation by actinoporins, as for Sticholysin II (StnII and Equinatoxin II (EqtxII. In this context, the current work intends to characterize the influence of distinct solution conditions in the conformational behavior of these proteins through molecular dynamics (MD simulations. The obtained data offer structural insights into actinoporins dynamics in solution, characterizing its conformational behavior at the atomic level, in accordance with previous experimental data on StnII and EqtxII hemolytic activities.

  15. ''FIXBOX'' - a new technique for the reliable conditioning of plutonium waste solutions

    International Nuclear Information System (INIS)

    Bruchertseifer, H.; Sommer, E.; Steinemann, M.; Bart, G.

    1994-01-01

    ''FIXBOX'' - A new technique and facility for the conditioning of plutonium waste solutions has been developed and brought into operation in the Hot-laboratory at PSI, for the solidification of the waste from the research programmes. The facility is situated in glove-boxes for handling alpha activity and gamma-shielded for conditioning of fission product-containing waste. This report gives a brief description of the FIXBOX facility, the procedure and the first results of the cementation of plutonium waste solutions. As a result of this solidification, the actinide waste is homogeneous and strongly bound in the cement. The presence of gluconic acid and other complexing agents in the waste solution will not disturb this process. (author) figs., tabs., refs

  16. Spinning in different directions: western rock lobster larval condition varies with eddy polarity, but does their diet?

    OpenAIRE

    O'Rorke, R.; Jeffs, A. G.; Wang, M.; Waite, A. M.; Beckley, L. E.; Lavery, S. D.

    2015-01-01

    Larvae of the western rock lobster (Panulirus cygnus) that occur in the south-east Indian Ocean offshore of Western Australia have been found to be in poorer nutritional condition in anticyclonic compared with cyclonic mesoscale eddies. The reason for this is unknown, but culture-based experiments have shown that diet composition and water temperature are key determinants of phyllosoma health and survival. Whether differences in prey composition are the cause of poor phyllosoma co...

  17. A cyano-terminated dithienyldiketopyrrolopyrrole dimer as a solution processable ambipolar semiconductor under ambient conditions.

    Science.gov (United States)

    Wang, Li; Zhang, Xiaojie; Tian, Hongkun; Lu, Yunfeng; Geng, Yanhou; Wang, Fosong

    2013-12-14

    A cyano-terminated dimer of dithienyldiketopyrrolopyrrole (TDPP), DPP2-CN, is a solution processable ambipolar semiconductor with field-effect hole and electron mobilities of 0.066 and 0.033 cm(2) V(-1) s(-1), respectively, under ambient conditions.

  18. A semi-analytical solution for viscothermal wave propagation in narrow gaps with arbitrary boundary conditions.

    NARCIS (Netherlands)

    Wijnant, Ysbrand H.; Spiering, R.M.E.J.; Blijderveen, M.; de Boer, Andries

    2006-01-01

    Previous research has shown that viscothermal wave propagation in narrow gaps can efficiently be described by means of the low reduced frequency model. For simple geometries and boundary conditions, analytical solutions are available. For example, Beltman [4] gives the acoustic pressure in the gap

  19. Multiplicity of solutions for Dirichlet boundary conditions of second-order quasilinear equations with impulsive effects

    Directory of Open Access Journals (Sweden)

    Tengfei Shen

    2015-12-01

    Full Text Available This paper deals with the multiplicity of solutions for Dirichlet boundary conditions of second-order quasilinear equations with impulsive effects. By using critical point theory, a new result is obtained. An example is given to illustrate the main result.

  20. Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

    Science.gov (United States)

    Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

    2017-02-01

    Currently, few thermal infrared measurements exist of fine particulate (samples (e.g. minerals, mineral mixtures, rocks, meteorites, and lunar soils) measured under simulated lunar conditions. Such measurements are fundamental for interpreting thermal infrared (TIR) observations by the Diviner Lunar Radiometer Experiment (Diviner) onboard NASA's Lunar Reconnaissance Orbiter as well as future TIR observations of the Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (sample as we systematically vary parameters that control the near-surface environment in our vacuum chamber (atmospheric pressure, incident solar-like radiation, and sample cup temperature). The atmospheric pressure is varied between ambient (1000 mbar) and vacuum (radiation is varied between 52 and 146 mW/cm2, and the sample cup temperature is varied between 325 and 405 K. Spectral changes are characterized as each parameter is varied, which highlight the sensitivity of thermal infrared emissivity spectra to the atmospheric pressure and the incident solar-like radiation. Finally spectral measurements of Apollo 15 and 16 bulk lunar soils are compared with Diviner thermal infrared observations of the Apollo 15 and 16 sampling sites. This comparison allows us to constrain the temperature and pressure conditions that best simulate the near-surface environment of the Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

  1. Evolution of deformation structures under varying loading conditions followed in situ by high angular resolution 3DXRD

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, B.

    2009-01-01

    copper to different loading conditions are presented: during uninterrupted tensile deformation, formation of subgrains can be observed concurrently with broadening of the Bragg reflection shortly after onset of plastic deformation. With continued tensile deformation, the subgrain structure develops...... intermittently. When the traction is terminated, stress relaxation occurs and number, size and orientation of subgrains are found to be constant. The subgrain structure freezes and only a minor clean-up of the dislocation structure is observed. When changing the tensile direction after pre-deformation in tension...

  2. Positive nondecreasing solutions for a multi-term fractional-order functional differential equation with integral conditions

    OpenAIRE

    Ahmed M. A. El-Sayed; Ebtisam O. Bin-Taher

    2011-01-01

    In this article, we prove the existence of positive nondecreasing solutions for a multi-term fractional-order functional differential equations. We consider Cauchy boundary problems with: nonlocal conditions, two-point boundary conditions, integral conditions, and deviated arguments.

  3. Effects of Temperature on Solute Transport Parameters in Differently-Textured Soils at Saturated Condition

    Science.gov (United States)

    Hamamoto, S.; Arihara, M.; Kawamoto, K.; Nishimura, T.; Komatsu, T.; Moldrup, P.

    2014-12-01

    Subsurface warming driven by global warming, urban heat islands, and increasing use of shallow geothermal heating and cooling systems such as the ground source heat pump, potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to increased subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in soil columns under temperature control to investigate effects of temperature on solute transport parameters, such as solute dispersion and diffusion coefficients, hydraulic conductivity, and retardation factor. Toyoura sand, Kaolin clay, and intact loamy soils were used in the experiments. Intact loamy soils were taken during a deep well boring at the Arakawa Lowland in Saitama Prefecture, Japan. In the transport experiments, the core sample with 5-cm diameter and 4-cm height was first isotropically consolidated, whereafter 0.01M KCl solution was injected to the sample from the bottom. The concentrations of K+ and Cl- in the effluents were analyzed by an ion chromatograph to obtain solute breakthrough curves. The solute transport parameters were calculated from the breakthrough curves. The experiments were conducted under different temperature conditions (15, 25, and 40 oC). The retardation factor for the intact loamy soils decreased with increasing temperature, while water permeability increased due to reduced viscosity of water at higher temperature. Opposite, the effect of temperature on solute dispersivity for the intact loamy soils was insignificant. The effects of soil texture on the temperature dependency of the solute transport characteristics will be further investigated from comparison of results from differently-textured samples.

  4. Modeling hydrate formation conditions in the presence of electrolytes and polar inhibitor solutions

    International Nuclear Information System (INIS)

    Osfouri, Shahriar; Azin, Reza; Gholami, Reza; Izadpanah, Amir Abbas

    2015-01-01

    Highlights: • A new predictive model is proposed for prediction of hydrate formation pressures. • A new local composition model was used to evaluate water activity in the presence of electrolyte. • MEG, DEG and TEG were used to test ability of the proposed model in the presence of polar inhibitors. • Cage occupancies by methane for the small cage were higher than carbon dioxide for gas mixtures. • The proposed model gives better match with experimental data in mixed electrolyte solutions. - Abstract: In this paper, a new predictive model is proposed for prediction of gas hydrate formation conditions in the presence of single and mixed electrolytes and solutions containing both electrolyte and a polar inhibitor such as monoethylene glycol (MEG), diethylene glycol (DEG) and triethylene glycol (TEG). The proposed model is based on the γ–φ approach, which uses modified Patel–Teja equation of state (VPT EOS) for characterizing the vapor phase, the solid solution theory by van der Waals and Platteeuw for modeling the hydrate phase, the non-electrolyte NRTL-NRF local composition model and Pitzer–Debye–Huckel equation as short-range and long-range contributions to calculate water activity in single electrolyte solutions. Also, the Margules equation was used to determine the activity of water in solutions containing polar inhibitor (glycols). The model predictions are in acceptable agreement with experimental data. For single electrolyte solutions, the model predictions are similar to available models, while for mixtures of electrolytes and mixtures of electrolytes and inhibitors, the proposed model gives significantly better predictions. In addition, the absolute average deviation of hydrate formation pressures (AADP) for 144 experimental data in solutions containing single electrolyte is 5.86% and for 190 experimental data in mixed electrolytes solutions is 5.23%. Furthermore, the proposed model has an AADP of 14.13%, 5.82% and 5.28% in solutions

  5. Research on ration selection of mixed absorbent solution for membrane air-conditioning system

    International Nuclear Information System (INIS)

    Li, Xiu-Wei; Zhang, Xiao-Song; Wang, Fang; Zhao, Xiao; Zhang, Zhuo

    2015-01-01

    Highlights: • We derive models of the membrane air-conditioning system with mixed absorbents. • We make analysis on system COP, cost-effectiveness and economy. • The paper provides a new method for ideal absorbent selection. • The solutes concentration of 50% achieves the best cost-effectiveness and the economy. - Abstract: Absorption air-conditioning system is a good alternative to vapor compression system for developing low carbon society. To improve the performance of the traditional absorption system, the membrane air-conditioning system is configured and its COP can reach as high as 6. Mixed absorbents are potential for cost reduction of the membrane system while maintaining a high COP. On the purpose of finding ideal mixed absorbent groups, this paper makes analysis on COP, cost-effectiveness and economy of the membrane system with mixed LiBr–CaCl 2 absorbent solution. The models of the system have been developed for the analysis. The results show the COP is higher for the absorbent groups with lower concentration of the total solute and higher concentration ratio of LiBr. It also reveals when the total solutes concentration is about 50%, it achieves the best cost-effectiveness and the economy. The process of the analysis provides a useful method for mixed absorbents selection

  6. Analytical solutions of couple stress fluid flows with slip boundary conditions

    Directory of Open Access Journals (Sweden)

    Devakar M.

    2014-09-01

    Full Text Available In the present article, the exact solutions for fundamental flows namely Couette, Poiseuille and generalized Couette flows of an incompressible couple stress fluid between parallel plates are obtained using slip boundary conditions. The effect of various parameters on velocity for each problem is discussed. It is found that, for each of the problems, the solution in the limiting case as couple stresses approaches to zero is similar to that of classical viscous Newtonian fluid. The results indicate that, the presence of couple stresses decreases the velocity of the fluid.

  7. POSITIVE SOLUTIONS OF A NONLINEAR THREE-POINT EIGENVALUE PROBLEM WITH INTEGRAL BOUNDARY CONDITIONS

    Directory of Open Access Journals (Sweden)

    FAOUZI HADDOUCHI

    2015-11-01

    Full Text Available In this paper, we study the existence of positive solutions of a three-point integral boundary value problem (BVP for the following second-order differential equation u''(t + \\lambda a(tf(u(t = 0; 0 0 is a parameter, 0 <\\eta < 1, 0 <\\alpha < 1/{\\eta}. . By using the properties of the Green's function and Krasnoselskii's fixed point theorem on cones, the eigenvalue intervals of the nonlinear boundary value problem are considered, some sufficient conditions for the existence of at least one positive solutions are established.

  8. Investigating the emerging role of comparative proteomics in the search for new biomarkers of metal contamination under varying abiotic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vellinger, Céline, E-mail: celine.vellinger@gmail.com [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France); Sohm, Bénédicte, E-mail: benedicte.sohm@univ-lorraine.fr [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France); Parant, Marc, E-mail: marc.parant@univ-lorraine.fr [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France); Immel, Françoise, E-mail: Francoise.Immel@u-bourgogne.fr [Biogéosciences, CNRS UMR 6282, Université de Bourgogne – Dijon (France); Usseglio-Polatera, Philippe, E-mail: philippe.usseglio-polatera@univ-lorraine.fr [Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), CNRS UMR 7360, Université de Lorraine – Metz (France)

    2016-08-15

    This study aims at investigating the potential use of comparative proteomics as a multi-marker approach of metal contamination, taking into account the potential confounding effect of water temperature. The major objective was to identify combinations of proteins specifically responding to a given metal, even if included in a metal mixture. The diagnostic approach was performed via the comparative analysis of protein expression on spot mapping provided by adult males of Gammarus pulex (Amphipoda, Crustacea) respectively exposed to arsenate (As), cadmium (Cd) or a binary mixture of these metals (AsCd) at three realistic temperatures (5, 10 and 15 °C). Proteomic expression analysis was performed by Differential in-Gel Electrophoresis (2D-DiGE), and completed by an adapted inferential statistical approach. Combinations of under/over-expressed protein spots discriminated the metal identity. However, none of these spots discriminated both the individual metal effect (As or Cd) and its effect in metal mixture (AsCd) whatever the tested temperature. Some limits of the two-dimensional analysis of protein spot maps in G. pulex have been highlighted: (i) the presence of contaminating peptides and/or abundant “déja-vu” proteins which can mask the responses of other proteins of interest or (ii) the presence of post-translational modifications. An optimization of the experimental design (especially during the sample preparation) has been described for future investigations. This study has also highlighted (i) the importance of precisely identifying the protein spots of interest to avoid erroneous interpretations in terms of action mechanisms of chemicals and (ii) the importance of working under controlled laboratory conditions with a temperature close to 10 °C. In such conditions, we have demonstrated a higher impact of As than Cd on the energetic metabolism of Gammarus. This As impact is reduced in AsCd mixture confirming the antagonistic interaction of this binary

  9. Investigating the emerging role of comparative proteomics in the search for new biomarkers of metal contamination under varying abiotic conditions

    International Nuclear Information System (INIS)

    Vellinger, Céline; Sohm, Bénédicte; Parant, Marc; Immel, Françoise; Usseglio-Polatera, Philippe

    2016-01-01

    This study aims at investigating the potential use of comparative proteomics as a multi-marker approach of metal contamination, taking into account the potential confounding effect of water temperature. The major objective was to identify combinations of proteins specifically responding to a given metal, even if included in a metal mixture. The diagnostic approach was performed via the comparative analysis of protein expression on spot mapping provided by adult males of Gammarus pulex (Amphipoda, Crustacea) respectively exposed to arsenate (As), cadmium (Cd) or a binary mixture of these metals (AsCd) at three realistic temperatures (5, 10 and 15 °C). Proteomic expression analysis was performed by Differential in-Gel Electrophoresis (2D-DiGE), and completed by an adapted inferential statistical approach. Combinations of under/over-expressed protein spots discriminated the metal identity. However, none of these spots discriminated both the individual metal effect (As or Cd) and its effect in metal mixture (AsCd) whatever the tested temperature. Some limits of the two-dimensional analysis of protein spot maps in G. pulex have been highlighted: (i) the presence of contaminating peptides and/or abundant “déja-vu” proteins which can mask the responses of other proteins of interest or (ii) the presence of post-translational modifications. An optimization of the experimental design (especially during the sample preparation) has been described for future investigations. This study has also highlighted (i) the importance of precisely identifying the protein spots of interest to avoid erroneous interpretations in terms of action mechanisms of chemicals and (ii) the importance of working under controlled laboratory conditions with a temperature close to 10 °C. In such conditions, we have demonstrated a higher impact of As than Cd on the energetic metabolism of Gammarus. This As impact is reduced in AsCd mixture confirming the antagonistic interaction of this binary

  10. An empirical assessment of driver motivation and emotional states in perceived safety margins under varied driving conditions.

    Science.gov (United States)

    Zhang, Yu; Kaber, David B

    2013-01-01

    Motivation models in driving behaviour postulate that driver motives and emotional states dictate risk tolerance under various traffic conditions. The present study used time and driver performance-based payment systems to manipulate motivation and risk-taking behaviour. Ten participants drove to a predefined location in a simulated driving environment. Traffic patterns (density and velocity) were manipulated to cause driver behaviour adjustments due to the need to conform with the social norms of the roadway. The driving environment complexity was investigated as a mediating factor in risk tolerance. Results revealed the performance-based payment system to closely relate to risk-taking behaviour as compared with the time-based payment system. Drivers conformed with social norms associated with specific traffic patterns. Higher roadway complexity led to a more conservative safety margins and speeds. This research contributes to the further development of motivational models of driver behaviour. This study provides empirical justification for two motivation factors in driver risk-taking decisions, including compliance with social norm and emotions triggered by incentives. Environment complexity was identified as a mediating factor in motivational behaviour model. This study also recommended safety margin measures sensitive to changes in driver risk tolerance.

  11. Modulating the phenology and yield of camelina sativa L. by varying sowing dates under water deficit stress conditions

    Directory of Open Access Journals (Sweden)

    Ejaz Ahmad Waraich

    2017-05-01

    Full Text Available Camelina (Camelina sativa L. an oilseed crop has emerged as a potential source for biofuels and bio-products. Camelina is an economic crop due to its less requirements of agronomic inputs as compared to other oilseed crops. However, it is direly required to evaluate the adaptability of camelina and characterize its production potential. Therefore, a pot experiment was carried out in rain out shelter at the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to optimize appropriate sowing date with respect to growth and yield potential of different genotypes of camelina under drought stress. Completely randomized design with factorial arrangements was adopted. Three sowing dates with the difference of 10 days (November 13 th, 23rd and December 03rd, two water regimes (100% FC and 60% FC and two camlena genotypes (611 and 618 were used in this experiment. Results indicated that camelina growth and yield related traits were significantly influenced by difference in sowing dates and water regimes. Maximum leaf area index (LAI, crop growth rate (CGR, leaf area duration (LAD, net assimilation rate (NAR and yield related traits were recorded with early sowing (13th November which was followed by sowing on 23rd November and least values of these variables were recorded in late sowing (December 03rd. Plants grown under water deficit conditions (60% FC showed the decreased values of LAI, CGR, LAD, NAR and yield related attributes as compared to normally irrigated plants (100% FC. However, the response of genotypes of camelina 611 and 618 remained statistically similar to each other.

  12. Interaction between U(VI) and Fe(II) in aqueous solution under anaerobic conditions. Closed system experiments

    International Nuclear Information System (INIS)

    Myllykylae, E.; Ollila, K.

    2011-01-01

    The aim of these experiments is to investigate the potential reduction of U(VI) carbonate and hydroxide complexes by aqueous Fe(II). This reduction phenomenon could be important under the disposal conditions of spent fuel. If groundwater enters the copper/iron canister, alpha radiolysis of the water may locally induce oxidizing conditions on the surface of UO 2 fuel, leading to the dissolution of UO 2 as more soluble U(VI) species. A potential reducing agent in the intruding water is Fe(II)(aq) from anaerobic corrosion of the copper/iron canister. The reduction of U(VI) to U(IV) would substantially decrease the solubility of U as well as co-precipitate other actinides and radionuclides. The interaction experiments were conducted in 0.01 M NaCl and 0.002 M NaHCO 3 solutions using an initial uranium concentration of either 8.4 x 10 -8 or 4.2 x 10 -7 mol/L with an initial Fe(II) concentration of 1.8 x 10 -6 in the NaCl solutions and 1.3 x 10 -6 mol/L in the NaHCO 3 solutions. Only after an equilibration period for U(VI) complexation was Fe(II) added to the solutions. The reaction times varied from 1 week to 5 months. For extra protection against O 2 , even inside a glove-box (N 2 atmosphere), the plastic reaction vessels were closed in metallic containers. The concentrations of U, Fe TOT and Fe(II) were analysed as a function of time for unfiltered, micro- and ultrafiltered samples. In addition, the precipitate on the ultrafilters was analysed with ESEM-EDS. The evolution of pH and Eh values was measured. The oxidation state of U in solution was preliminarily analysed for chosen periods. The results of the tests in 0.01 M NaCl showed an initial rapid decrease in U concentration after the addition of Fe(II) to the solution. The U found on test vessel walls at the end of the reaction periods, as well as the ESEM-EDS analyses of the filtered precipitates from the test solutions, showed that precipitation of U had occurred. The oxidation state analyses showed the presence

  13. Rare Earth Element Behavior During Incongruent Weathering and Varying Discharge Conditions in Silicate Dominated River Systems: The Australian Victorian Alps

    Science.gov (United States)

    Hagedorn, K. B.; Cartwright, I.

    2008-12-01

    The distribution of rare earth elements (REE) and trace elements was measured by ICP-MS on fresh, slightly weathered and weathered granite and surface water samples from a network of 11 pristine rivers draining the Australian Victorian Alps during (i) high and (ii) low discharge conditions. River water REE concentrations are largely derived from atmospheric precipitation (rain, snow), as indicated by similar Chondrite normalized REE patterns (higher LREE over HREE; negative Ce anomalies, positive Eu anomalies) and similar total REE concentrations during both dry and wet seasons. Calculations based on the covariance between REE and Cl concentrations and oxygen and hydrogen isotopes indicate precipitation input coupled with subsequent evaporation may account for 30% o 100% of dissolved REE in stream waters. The dissolved contribution to the granitic substratum to stream water comes mainly from the transformation of plagioclase to smectite, kaolinite and gibbsite and minor apatite dissolution. However, since most REE of the regional granite are present in accessory minerals (titanite, zircon, etc.) they do not significantly contribute to the river REE pool. REE concentrations drop sharply downstream as a result of dilution and chemical attenuation. A trend of downstream enrichment of the heavier REE is due to selective partitioning of the lighter REE (as both free REE or REECO3 complexes) to hydrous oxides of suspended Al which, in turn, is controlled by a downstream increase of pH to values > 6.1 (for free REE) and > 7.3 (for REECO3 complexes). Although most circumneutral waters were supersaturated with REE phosphate compounds, precipitation of LnPO4 is not believed to have been a dominant process because the predicted phosphate fractionation pattern is inconsistent with the observed trends. Negative saturation indices of hydrous ferric oxides also militate against surface complexation onto goethite. Instead, REE attenuation most likely resulted from adsorption onto

  14. Large deviations for solutions to stochastic recurrence equations under Kesten's condition

    DEFF Research Database (Denmark)

    Buraczewski, Dariusz; Damek, Ewa; Mikosch, Thomas Valentin

    2013-01-01

    In this paper we prove large deviations results for partial sums constructed from the solution to a stochastic recurrence equation. We assume Kesten’s condition [17] under which the solution of the stochastic recurrence equation has a marginal distribution with power law tails, while the noise...... sequence of the equations can have light tails. The results of the paper are analogs of those obtained by A.V. and S.V. Nagaev [21, 22] in the case of partial sums of iid random variables. In the latter case, the large deviation probabilities of the partial sums are essentially determined by the largest...... step size of the partial sum. For the solution to a stochastic recurrence equation, the magnitude of the large deviation probabilities is again given by the tail of the maximum summand, but the exact asymptotic tail behavior is also influenced by clusters of extreme values, due to dependencies...

  15. Spectroscopic study of cystine adsorption on pyrite surface: From vacuum to solution conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Arenillas, M.; Mateo-Marti, E., E-mail: mateome@cab.inta-csic.es

    2015-09-08

    Highlights: • Successful adsorption of cystine on pyrite surface under several conditions. • Detailed XPS spectroscopic characterization of cystine adsorption on pyrite surface. • Spectroscopy evidence, oxidation and anoxic conditions adjust molecular adsorption. • Molecular chemistry on pyrite is driven depending on the surrounding conditions. • The cystine/pyrite(100) model is in good agreement with Wächtershäuser’s theory. - Abstract: We characterized the adsorption of cystine molecules on pyrite surface via X-ray photoelectron spectroscopy. Anoxic conditions were simulated under ultra-high-vacuum conditions. In contrast, to simulate oxidation conditions, the molecules were adsorbed on pyrite surface from solution. A novel comparative analysis revealed remarkable differences with respect to molecular adsorption and surface chemistry induced by environmental conditions. Molecular adsorption under anoxic conditions was observed to be more favorable, concentrating a large number of molecules on the surface and two different chemical species. In contrast, the presence of oxygen induced an autocatalytic oxidation process on the pyrite surface, which facilitated water binding on pyrite surface and partially blocked molecular adsorption. Pyrite is a highly reactive surface and contains two crucial types of surface functional groups that drive molecular chemistry on the surface depending on the surrounding conditions. Therefore, the system explored in this study holds interesting implications for supporting catalyzed prebiotic chemistry reactions.

  16. Spectroscopic study of cystine adsorption on pyrite surface: From vacuum to solution conditions

    International Nuclear Information System (INIS)

    Sanchez-Arenillas, M.; Mateo-Marti, E.

    2015-01-01

    Highlights: • Successful adsorption of cystine on pyrite surface under several conditions. • Detailed XPS spectroscopic characterization of cystine adsorption on pyrite surface. • Spectroscopy evidence, oxidation and anoxic conditions adjust molecular adsorption. • Molecular chemistry on pyrite is driven depending on the surrounding conditions. • The cystine/pyrite(100) model is in good agreement with Wächtershäuser’s theory. - Abstract: We characterized the adsorption of cystine molecules on pyrite surface via X-ray photoelectron spectroscopy. Anoxic conditions were simulated under ultra-high-vacuum conditions. In contrast, to simulate oxidation conditions, the molecules were adsorbed on pyrite surface from solution. A novel comparative analysis revealed remarkable differences with respect to molecular adsorption and surface chemistry induced by environmental conditions. Molecular adsorption under anoxic conditions was observed to be more favorable, concentrating a large number of molecules on the surface and two different chemical species. In contrast, the presence of oxygen induced an autocatalytic oxidation process on the pyrite surface, which facilitated water binding on pyrite surface and partially blocked molecular adsorption. Pyrite is a highly reactive surface and contains two crucial types of surface functional groups that drive molecular chemistry on the surface depending on the surrounding conditions. Therefore, the system explored in this study holds interesting implications for supporting catalyzed prebiotic chemistry reactions

  17. Processes influencing migration of bioavailable organic compounds from polymers - investigated during biotic and abiotic testing under static and non-static conditions with varying S/V-ratios

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Arvin, Erik; Albrechtsen, Hans-Jørgen

    . The bioavailable migration from the polymer surface was influence by diffusion over the solid-liquid boundary layer under sterile conditions, which resulted in an inversely proportionally relationship between bioavailable migration expressed per unit surface area of material and the surface to volume ratio (S/V-ratio...... the effect of the boundary layer, since bioavailable migration was continuously consumed by the bacteria. Thus the driving force for the diffusion process was maintained at a maximum, thereby enhancing the bioavailable migration from the material surfaces. Thus neither non-static conditions nor varying S/V-ratios...

  18. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Tanabe, Tatsuhiko; Nakajima, Hajime

    1994-01-01

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000 C in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000 to 900 C. The trend observed in the tests from 900 to 1000 C can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900 C plays the role of the protective barrier against the boron dissipation into the environment. (orig.)

  19. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Tanabe, Tatsuhiko.

    1993-09-01

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000degC in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the born content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000degC to 900degC. The trend observed in the tests from 900degC to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (author)

  20. Analytical solution describing pesticide volatilization from soil affected by a change in surface condition.

    Science.gov (United States)

    Yates, S R

    2009-01-01

    An analytical solution describing the fate and transport of pesticides applied to soils has been developed. Two pesticide application methods can be simulated: point-source applications, such as idealized shank or a hot-gas injection method, and a more realistic shank-source application method that includes a vertical pesticide distribution in the soil domain due to a soil fracture caused by a shank. The solutions allow determination of the volatilization rate and other information that could be important for understanding fumigant movement and in the development of regulatory permitting conditions. The solutions can be used to characterize differences in emissions relative to changes in the soil degradation rate, surface barrier conditions, application depth, and soil packing. In some cases, simple algebraic expressions are provided that can be used to obtain the total emissions and total soil degradation. The solutions provide a consistent methodology for determining the total emissions and can be used with other information, such as field and laboratory experimental data, to support the development of fumigant regulations. The uses of the models are illustrated by several examples.

  1. Characterization of Skeletonema costatum Intracellular Organic Matter and Study of Nanomechanical Properties under Different Solution Conditions

    KAUST Repository

    Gutierrez, Leonardo

    2016-06-17

    In the current investigation, a rigorous characterization of the high molecular weight (HMW) compounds of Skeletonema costatum (SKC) intracellular organic matter (IOM), including nanomechanical properties, was conducted. HMW SKC-IOM was characterized as a mixture of polysaccharides, proteins, and lipids. Atomic force microscopy (AFM) provided crucial information of this isolate at a nanoscale resolution. HMW SKC-IOM showed highly responsive to solution chemistry: fully extended chains at low ionic strength, and compressing structures with increasing electrolyte concentration in solution. Interestingly, two regions of different nanomechanical properties were observed: (a) Region #1: located farther from the substrate and showing extended polymeric chains, and (b) Region #2: located <10 nm above the substrate and presenting compressed structures. The polymer length, polymer grafting density, and compressibility of these two regions were highly influenced by solution conditions. Results suggest that steric interactions originating from HMW SKC-IOM polymeric structure would be a dominant interacting mechanism with surfaces. The current investigation has successfully applied models of polymer physics to describe the complex HMW SKC-IOM structural conformation at different solution conditions. The detailed methodology presented provides a tool to characterize and understand biopolymers interactions with surfaces, including filtration membranes, and can be extended to other environmentally relevant organic compounds.

  2. Stokes system with solution-dependent threshold slip boundary conditions: Analysis, approximation and implementation

    Czech Academy of Sciences Publication Activity Database

    Haslinger, Jaroslav; Kučera, R.; Šátek, V.

    2017-01-01

    Roč. 22, October 2017 (2017), s. 1-14 ISSN 1081-2865 R&D Projects: GA MŠk LQ1602; GA ČR(CZ) GA17-01747S Institutional support: RVO:68145535 Keywords : Stokes system * threshold slip boundary conditions * solution dependent slip function Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 2.953, year: 2016 http://journals.sagepub.com/doi/abs/10.1177/1081286517716222

  3. Stokes system with solution-dependent threshold slip boundary conditions: Analysis, approximation and implementation

    Czech Academy of Sciences Publication Activity Database

    Haslinger, Jaroslav; Kučera, R.; Šátek, V.

    2017-01-01

    Roč. 22, October 2017 (2017), s. 1-14 ISSN 1081-2865 R&D Projects: GA MŠk LQ1602; GA ČR(CZ) GA17-01747S Institutional support: RVO:68145535 Keywords : Stokes system * threshold slip boundary conditions * solution dependent slip function Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 2.953, year: 2016 http:// journals .sagepub.com/doi/abs/10.1177/1081286517716222

  4. Optimality conditions for the numerical solution of optimization problems with PDE constraints :

    Energy Technology Data Exchange (ETDEWEB)

    Aguilo Valentin, Miguel Alejandro; Ridzal, Denis

    2014-03-01

    A theoretical framework for the numerical solution of partial di erential equation (PDE) constrained optimization problems is presented in this report. This theoretical framework embodies the fundamental infrastructure required to e ciently implement and solve this class of problems. Detail derivations of the optimality conditions required to accurately solve several parameter identi cation and optimal control problems are also provided in this report. This will allow the reader to further understand how the theoretical abstraction presented in this report translates to the application.

  5. Microstructural Evidences of Intergranular Pressure Solution during Frictional Sliding at Hydrothermal Conditions

    Science.gov (United States)

    Ma, X.; Yao, S.; He, C.

    2017-12-01

    In the framework of rate- and state-dependent friction, velocity weakening is the result of a healing effect at intergranular contacts that is stronger than the instantaneous rate effect. Intergranular pressure solution has been proposed to be a feasible mechanism for the frictional healing effect (He et al., 2013), but to date no substantial evidences have been reported in related microstructures. In this study we report our reanalyses on samples of plagioclase gouge deformed at hydrothermal conditions with effective normal stresses of 100 MPa, 200 MPa, and 300 MPa, pore pressures of 30 MPa and 100 MPa, and temperatures from 100oC to 600oC. With an Inlens image detector in a scanning electron microscope, our focus is to find the evidences of the pressure solution processes during frictional sliding. As it has been difficult to observe the signatures of pressure solution during frictional sliding at the solution sites due to the short contact time of frequently-switching contact pairs, now we focus on the results of precipitation instead, which is the final process of pressure solution. With high magnification, we find the following evidences of intergranular pressure solution: 1) crystal growth as a result of precipitation is ubiquitously observed in deformed samples at temperatures above 200oC; 2) very fine-grained precipitated particles with flaky morphologies typically appear in intensely sheared regions and between relatively large particles in moderately sheared regions; 3) the precipitated grains are concentrated periodically in zones orientated at 45-50 degrees to the fault strike. These observations indicate that intergranular pressure solution is the dominant process responsible for the frictional healing effect.

  6. Shock-jump conditions in a general medium: weak-solution approach

    Science.gov (United States)

    Forbes, L. K.; Krzysik, O. A.

    2017-05-01

    General conservation laws are considered, and the concept of a weak solution is extended to the case of an equation involving three space variables and time. Four-dimensional vector calculus is used to develop general jump conditions at a shock wave in the material. To illustrate the use of this result, jump conditions at a shock in unsteady three-dimensional compressible gas flow are presented. It is then proved rigorously that these reduce to the commonly assumed conditions in coordinates normal and tangential to the shock face. A similar calculation is also outlined for an unsteady three-dimensional shock in magnetohydrodynamics, and in a chemically reactive fluid. The technique is available for determining shock-jump conditions in quite general continuous media.

  7. Exact Solution of the Six-Vertex Model with Domain Wall Boundary Conditions. Disordered Phase

    CERN Document Server

    Bleher, P M

    2005-01-01

    The six-vertex model, or the square ice model, with domain wall boundary conditions (DWBC) has been introduced and solved for finite $N$ by Korepin and Izergin. The solution is based on the Yang-Baxter equations and it represents the free energy in terms of an $N\\times N$ Hankel determinant. Paul Zinn-Justin observed that the Izergin-Korepin formula can be re-expressed in terms of the partition function of a random matrix model with a nonpolynomial interaction. We use this observation to obtain the large $N$ asymptotics of the six-vertex model with DWBC in the disordered phase. The solution is based on the Riemann-Hilbert approach and the Deift-Zhou nonlinear steepest descent method. As was noticed by Kuperberg, the problem of enumeration of alternating sign matrices (the ASM problem) is a special case of the the six-vertex model. We compare the obtained exact solution of the six-vertex model with known exact results for the 1, 2, and 3 enumerations of ASMs, and also with the exact solution on the so-called f...

  8. Radiolysis of cesium iodide solutions in conditions prevailing in a pressurized water reactor severe accident

    International Nuclear Information System (INIS)

    Lucas, M.

    1988-01-01

    Measurements were made of I/sub 2/ formed when aqueous cesium iodide (CsI) solutions were exposed to two temperatures, 43 and 95 0 C, with irradiation. Iodine partition coefficients were obtained from the experiments. The parameters varied were dose, CsI concentration, and Cs/sub 2/CO/sub 3/ concentration, in the presence of air-carbon dioxide and air-carbon dioxide-hydrogen mixtures, to provide information to calculate the form in which iodine released from fuel as CsI in a reactor accident might reach the environment. In a series of experiments, a two-compartment cell was used to trap the gaseous iodine produced. In this case, it was found that the quantity of gaseous iodine produced increased approximately linearly with the dose (at the dose rate used)

  9. Existence of solutions to second-order nonlinear coupled systems with nonlinear coupled boundary conditions

    Directory of Open Access Journals (Sweden)

    Imran Talib

    2015-12-01

    Full Text Available In this article, study the existence of solutions for the second-order nonlinear coupled system of ordinary differential equations $$\\displaylines{ u''(t=f(t,v(t,\\quad t\\in [0,1],\\cr v''(t=g(t,u(t,\\quad t\\in [0,1], }$$ with nonlinear coupled boundary conditions $$\\displaylines{ \\phi(u(0,v(0,u(1,v(1,u'(0,v'(0=(0,0, \\cr \\psi(u(0,v(0,u(1,v(1,u'(1,v'(1=(0,0, }$$ where $f,g:[0,1]\\times \\mathbb{R}\\to \\mathbb{R}$ and $\\phi,\\psi:\\mathbb{R}^6\\to \\mathbb{R}^2$ are continuous functions. Our main tools are coupled lower and upper solutions, Arzela-Ascoli theorem, and Schauder's fixed point theorem.

  10. Effect of solution treatment conditions on the sensitization of austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    XIAOFEI YU

    2009-11-01

    Full Text Available In this study, the impact of the conditions of solution treatment on the degree of sensitization (DOS of austenitic stainless steel (AISI 304 was investigated in detail. The results derived from the electrochemical potentiodynamic reactivation (EPR test indicated that the DOS decreased as the solution treatment temperature and time increased. The reason for this was studied via the SEM morphologies and EDS results, which indicated that the grain size influenced the DOS. Furthermore, cellular automaton (CA was utilized to simulate grain growth, the precipitation of Cr-rich carbides and the three dimensional distribution of the chromium concentration, which vividly illuminated the effect of the grain size on the DOS and was in accordance with the experiment results.

  11. Modeling of water and solute transport under variably saturated conditions: state of the art

    International Nuclear Information System (INIS)

    Lappala, E.G.

    1980-01-01

    This paper reviews the equations used in deterministic models of mass and energy transport in variably saturated porous media. Analytic, quasi-analytic, and numerical solution methods to the nonlinear forms of transport equations are discussed with respect to their advantages and limitations. The factors that influence the selection of a modeling method are discussed in this paper; they include the following: (1) the degree of coupling required among the equations describing the transport of liquids, gases, solutes, and energy; (2) the inclusion of an advection term in the equations; (3) the existence of sharp fronts; (4) the degree of nonlinearity and hysteresis in the transport coefficients and boundary conditions; (5) the existence of complex boundaries; and (6) the availability and reliability of data required by the models

  12. Numerical investigations of solute transport in bimodal porous media under dynamic boundary conditions

    Science.gov (United States)

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

    2016-04-01

    Quantification of flow and solute transport in the shallow subsurface adjacent to the atmosphere is decisive to prevent groundwater pollution and conserve groundwater quality, to develop successful remediation strategies and to understand nutrient cycling. In nature, due to erratic precipitation-evaporation patterns, soil moisture content and related hydraulic conductivity in the vadose zone are not only variable in space but also in time. Flow directions and flow paths locally change between precipitation and evaporation periods. This makes the identification and description of solute transport processes in the vadose zone a complex problem. Recent studies (Lehmann and Or, 2009; Bechtold et al., 2011a) focused on the investigation of upward transport of solutes during evaporation in heterogeneous soil columns, where heterogeneity was introduced by a sharp vertical material interface between two types of sand. Lateral solute transport through the interface in both (lateral) directions was observed at different depths of the investigated soil columns. Following recent approaches, we conduct two-dimensional numerical simulations in a similar setup which is composed of two sands with a sharp vertical material interface. The investigation is broadened from the sole evaporation to combined precipitation-evaporation cycles in order to quantify transport processes resulting from the combined effects of heterogeneous soil structure and dynamic flow conditions. Simulations are performed with a coupled finite volume and random walk particle tracking algorithm (Ippisch et al., 2006; Bechtold et al., 2011b). By comparing scenarios with cyclic boundary conditions and stationary counterparts with the same net flow rate, we found that duration and intensity of precipitation and evaporation periods potentially have an influence on lateral redistribution of solutes and thus leaching rates. Whether or not dynamic boundary conditions lead to significant deviations in the transport

  13. Symbolic computation of analytic approximate solutions for nonlinear differential equations with initial conditions

    Science.gov (United States)

    Lin, Yezhi; Liu, Yinping; Li, Zhibin

    2012-01-01

    The Adomian decomposition method (ADM) is one of the most effective methods for constructing analytic approximate solutions of nonlinear differential equations. In this paper, based on the new definition of the Adomian polynomials, and the two-step Adomian decomposition method (TSADM) combined with the Padé technique, a new algorithm is proposed to construct accurate analytic approximations of nonlinear differential equations with initial conditions. Furthermore, a MAPLE package is developed, which is user-friendly and efficient. One only needs to input a system, initial conditions and several necessary parameters, then our package will automatically deliver analytic approximate solutions within a few seconds. Several different types of examples are given to illustrate the validity of the package. Our program provides a helpful and easy-to-use tool in science and engineering to deal with initial value problems. Program summaryProgram title: NAPA Catalogue identifier: AEJZ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJZ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 4060 No. of bytes in distributed program, including test data, etc.: 113 498 Distribution format: tar.gz Programming language: MAPLE R13 Computer: PC Operating system: Windows XP/7 RAM: 2 Gbytes Classification: 4.3 Nature of problem: Solve nonlinear differential equations with initial conditions. Solution method: Adomian decomposition method and Padé technique. Running time: Seconds at most in routine uses of the program. Special tasks may take up to some minutes.

  14. Carbon allocation to major metabolites in illuminated leaves is not just proportional to photosynthesis when gaseous conditions (CO2 and O2 ) vary.

    Science.gov (United States)

    Abadie, Cyril; Bathellier, Camille; Tcherkez, Guillaume

    2018-04-01

    In gas-exchange experiments, manipulating CO 2 and O 2 is commonly used to change the balance between carboxylation and oxygenation. Downstream metabolism (utilization of photosynthetic and photorespiratory products) may also be affected by gaseous conditions but this is not well documented. Here, we took advantage of sunflower as a model species, which accumulates chlorogenate in addition to sugars and amino acids (glutamate, alanine, glycine and serine). We performed isotopic labelling with 13 CO 2 under different CO 2 /O 2 conditions, and determined 13 C contents to compute 13 C-allocation patterns and build-up rates. The 13 C content in major metabolites was not found to be a constant proportion of net fixed carbon but, rather, changed dramatically with CO 2 and O 2 . Alanine typically accumulated at low O 2 (hypoxic response) while photorespiratory intermediates accumulated under ambient conditions and at high photorespiration, glycerate accumulation exceeding serine and glycine build-up. Chlorogenate synthesis was relatively more important under normal conditions and at high CO 2 and its synthesis was driven by phosphoenolpyruvate de novo synthesis. These findings demonstrate that carbon allocation to metabolites other than photosynthetic end products is affected by gaseous conditions and therefore the photosynthetic yield of net nitrogen assimilation varies, being minimal at high CO 2 and maximal at high O 2 . © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  15. Influence of yeast strain, priming solution and temperature on beer bottle conditioning.

    Science.gov (United States)

    Marconi, Ombretta; Rossi, Serena; Galgano, Fernanda; Sileoni, Valeria; Perretti, Giuseppe

    2016-09-01

    Recently, there has been a significant increase in the number of microbreweries. Usually, craft beers are bottle conditioned; however, few studies have investigated beer refermentation. One of the objectives of this study was to evaluate the impacts of different experimental conditions, specifically yeast strain, priming solution and temperature, on the standard quality attributes, the volatile compounds and the sensory profile of the bottle-conditioned beer. The other aim was to monitor the evolution of volatile compounds and amino acids consumption throughout the refermentation process to check if it is possible to reduce the time necessary for bottle conditioning. The results indicate that the volatile profile was mainly influenced by the strain of yeast, and this may have obscured the possible impacts of the other parameters. Our results also confirm that the two yeast strains showed different metabolic activity, particularly with respect to esters production. Moreover, we found the Safbrew S-33® strain when primed with Siromix® and refermented at 30 °C yielded the fastest formation of higher alcohols while maintaining low production of off-flavours. These results suggest a formulation that may reduce the time needed for bottle conditioning without affecting the quality of the final beer which may simultaneously improve efficiency and economic profits. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  16. Food safety and ecologization: practical solutions to problems at the regional level in current economic conditions

    Directory of Open Access Journals (Sweden)

    Lysochenko Alla, A.

    2015-03-01

    Full Text Available Ensuring food security and greening both at the level of the country, and at the level of regions are main objectives of modern agroeconomic policy. The state support creates favorable conditions for dynamic development of agrarian and industrial complex, raises investment opportunities and competitiveness of agricultural producers. A realization of the actions directed on assistance to the enterprises making import-substituting production of the regional agro-industrial complex is actual in modern economic conditions. The solution of this problem consists of investment projects implementation and production expansion of the operating enterprises. Considering new economic conditions, the ensuring financial stability of agricultural producers, availability of the food to needy segments of the population, production of valeologically safe food, and also increase efficiency of use of natural resources and conditions along with preservation of quality of environment at the local, regional and global levels are particularly acute challenges. State regulation of development of an agrofood complex of Russia remains a necessary condition for its reproduction functioning, and the social and economic policy has to provide economic availability of the food to all groups of the population that causes need of standard and legal fixing of mechanisms offood security achievement at the regional level.

  17. Optimization of hydrostatic pressure at varied sonication conditions--power density, intensity, very low frequency--for isothermal ultrasonic sludge treatment.

    Science.gov (United States)

    Delmas, Henri; Le, Ngoc Tuan; Barthe, Laurie; Julcour-Lebigue, Carine

    2015-07-01

    This work aims at investigating for the first time the key sonication (US) parameters: power density (DUS), intensity (IUS), and frequency (FS) - down to audible range, under varied hydrostatic pressure (Ph) and low temperature isothermal conditions (to avoid any thermal effect). The selected application was activated sludge disintegration, a major industrial US process. For a rational approach all comparisons were made at same specific energy input (ES, US energy per solid weight) which is also the relevant economic criterion. The decoupling of power density and intensity was obtained by either changing the sludge volume or most often by changing probe diameter, all other characteristics being unchanged. Comprehensive results were obtained by varying the hydrostatic pressure at given power density and intensity. In all cases marked maxima of sludge disintegration appeared at optimum pressures, which values increased at increasing power intensity and density. Such optimum was expected due to opposite effects of increasing hydrostatic pressure: higher cavitation threshold then smaller and fewer bubbles, but higher temperature and pressure at the end of collapse. In addition the first attempt to lower US frequency down to audible range was very successful: at any operation condition (DUS, IUS, Ph, sludge concentration and type) higher sludge disintegration was obtained at 12 kHz than at 20 kHz. The same values of optimum pressure were observed at 12 and 20 kHz. At same energy consumption the best conditions - obtained at 12 kHz, maximum power density 720 W/L and 3.25 bar - provided about 100% improvement with respect to usual conditions (1 bar, 20 kHz). Important energy savings and equipment size reduction may then be expected. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Experimental quantification of solute transport through the vadose zone under dynamic boundary conditions with dye tracers and optical methods.

    Science.gov (United States)

    Cremer, Clemens; Neuweiler, Insa

    2017-04-01

    Knowledge of subsurface solute transport processes is vital to investigate e.g. groundwater contamination, nutrient uptake by plant roots and to implement remediation strategies. Beside field measurements and numerical simulations, physical laboratory experiments represent a way to establish process understanding and furthermore validate numerical schemes. Atmospheric forcings, such as erratically varying infiltration and evaporation cycles, subject the shallow subsurface to local and temporal variations in water content and associated hydraulic conductivity of the prevailing porous media. Those variations in material properties can cause flow paths to differ between upward and downward flow periods. Thereby, the unsaturated subsurface presents a highly complicated, dynamic system. Following an extensive systematical numerical investigation of flow and transport through bimodal, unsaturated porous media under dynamic boundary conditions (Cremer et al., 2016), we conduct physical laboratory experiments in a 22 cm x 8 cm x 1 cm flow cell where we introduce structural heterogeneity in the form sharp material interfaces between different porous media. In all experiments, a constant pressure head is implemented at the lower boundary, while cyclic infiltration-evaporation phases are applied at the soil surface. As a reference case a stationary infiltration with a rate corresponding to the cycle-averaged infiltration rate is applied. By initial application of dye tracers, solute transport within the domain is visualized such that transport paths and redistribution processes can be observed in a qualitative manner. Solute leaching is quantified at the bottom outlet, where breakthrough curves are obtained via spectroscopy. Liquid and vapor flow in and out of the domain is obtained from multiple balances. Thereby, the interplay of material structural heterogeneity and alternating flow (transport) directions and flow (transport) paths is investigated. Results show lateral

  19. Analytical solution for beam with time-dependent boundary conditions versus response spectrum

    International Nuclear Information System (INIS)

    Gou, P.F.; Panahi, K.K.

    2001-01-01

    This paper studies the responses of a uniform simple beam for which the supports are subjected to time-dependent conditions. Analytical solution in terms of series was presented for two cases: (1) Two supports of a simple beam are subjected to a harmonic motion, and (2) One of the two supports is stationary while the other is subjected to a harmonic motion. The results of the analytical solution were investigated and compared with the results of conventional response spectrum method using the beam finite element model. One of the applications of the results presented in this paper can be used to assess the adequacy and accuracy of the engineering approaches such as response spectra methods. It has been found that, when the excitation frequency equals the fundamental frequency of the beam, the results from response spectrum method are in good agreement with the exact calculation. The effects of initial conditions on the responses are also examined. It seems that the non-zero initial velocity has pronounced effects on the displacement time histories but it has no effect on the maximum accelerations. (author)

  20. Photochemical processing of aldrin and dieldrin in frozen aqueous solutions under arctic field conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, Glenn A.; Bausch, Alexandra R. [Department of Chemistry, Villanova University, Villanova, PA 19085 (United States); Grannas, Amanda M., E-mail: amanda.grannas@villanova.edu [Department of Chemistry, Villanova University, Villanova, PA 19085 (United States)

    2011-05-15

    Organochlorine (OC) contaminants are transported to the Polar Regions, where they have the potential to bioaccumulate, presenting a threat to the health of wildlife and indigenous communities. They deposit onto snowpack during winter, and accumulate until spring, when they experience prolonged solar irradiation until snowmelt occurs. Photochemical degradation rates for aldrin and dieldrin, in frozen aqueous solution made from MilliQ water, 500 {mu}M hydrogen peroxide solution or locally-collected melted snow were measured in a field campaign near Barrow, AK, during spring-summer 2008. Significant photoprocessing of both pesticides occurs; the reactions depend on temperature, depth within the snowpack and whether the predominant phase is ice or liquid water. The effect of species present in natural snowpack is comparable to 500 {mu}M hydrogen peroxide, pointing to the potential significance of snowpack-mediated reactions. Aldrin samples frozen at near 0 deg. C were more reactive than comparable liquid samples, implying that the microenvironments experienced on frozen ice surfaces are an important consideration. - Highlights: > Photodegradation rates for aldrin and dieldrin in frozen aqueous solutions made from MilliQ water, H{sub 2}O{sub 2} or melted snow are reported. > Photoprocessing depends on temperature, depth beneath the snowpack surface and dominant phase. > Species present in natural snowpack have a photosensitizing effect comparable to 500 {mu}M H{sub 2}O{sub 2}. > Aldrin samples frozen at near 0 deg. C were more reactive than comparable liquid samples. > Collectively we find that frozen aqueous surfaces play a unique role in aldrin and dieldrin photochemistry. - A field study finds that frozen aqueous solutions of aldrin and dieldrin undergo photochemical degradation under arctic snowpack conditions. The reactions are enhanced in frozen systems and by natural snowpack constituents.

  1. Tribological and Wear Performance of Carbide Tools with TiB2 PVD Coating under Varying Machining Conditions of TiAl6V4 Aerospace Alloy

    Directory of Open Access Journals (Sweden)

    Jose Mario Paiva

    2017-11-01

    Full Text Available Tribological phenomena and tool wear mechanisms during machining of hard-to-cut TiAl6V4 aerospace alloy have been investigated in detail. Since cutting tool wear is directly affected by tribological phenomena occurring between the surfaces of the workpiece and the cutting tool, the performance of the cutting tool is strongly associated with the conditions of the machining process. The present work shows the effect of different machining conditions on the tribological and wear performance of TiB2-coated cutting tools compared to uncoated carbide tools. FEM modeling of the temperature profile on the friction surface was performed for wet machining conditions under varying cutting parameters. Comprehensive characterization of the TiB2 coated vs. uncoated cutting tool wear performance was made using optical 3D imaging, SEM/EDX and XPS methods respectively. The results obtained were linked to the FEM modeling. The studies carried out show that during machining of the TiAl6V4 alloy, the efficiency of the TiB2 coating application for carbide cutting tools strongly depends on cutting conditions. The TiB2 coating is very efficient under roughing at low speeds (with strong buildup edge formation. In contrast, it shows similar wear performance to the uncoated tool under finishing operations at higher cutting speeds when cratering wear predominates.

  2. Automatic Traffic Data Collection under Varying Lighting and Temperature Conditions in Multimodal Environments: Thermal versus Visible Spectrum Video-Based Systems

    Directory of Open Access Journals (Sweden)

    Ting Fu

    2017-01-01

    Full Text Available Vision-based monitoring systems using visible spectrum (regular video cameras can complement or substitute conventional sensors and provide rich positional and classification data. Although new camera technologies, including thermal video sensors, may improve the performance of digital video-based sensors, their performance under various conditions has rarely been evaluated at multimodal facilities. The purpose of this research is to integrate existing computer vision methods for automated data collection and evaluate the detection, classification, and speed measurement performance of thermal video sensors under varying lighting and temperature conditions. Thermal and regular video data was collected simultaneously under different conditions across multiple sites. Although the regular video sensor narrowly outperformed the thermal sensor during daytime, the performance of the thermal sensor is significantly better for low visibility and shadow conditions, particularly for pedestrians and cyclists. Retraining the algorithm on thermal data yielded an improvement in the global accuracy of 48%. Thermal speed measurements were consistently more accurate than for the regular video at daytime and nighttime. Thermal video is insensitive to lighting interference and pavement temperature, solves issues associated with visible light cameras for traffic data collection, and offers other benefits such as privacy, insensitivity to glare, storage space, and lower processing requirements.

  3. Hydro-dynamic Solute Transport under Two-Phase Flow Conditions.

    Science.gov (United States)

    Karadimitriou, Nikolaos K; Joekar-Niasar, Vahid; Brizuela, Omar Godinez

    2017-07-26

    There are abundant examples of natural, engineering and industrial applications, in which "solute transport" and "mixing" in porous media occur under multiphase flow conditions. Current state-of-the-art understanding and modelling of such processes are established based on flawed and non-representative models. Moreover, there is no direct experimental result to show the true hydrodynamics of transport and mixing under multiphase flow conditions while the saturation topology is being kept constant for a number of flow rates. With the use of a custom-made microscope, and under well-controlled flow boundary conditions, we visualized directly the transport of a tracer in a Reservoir-on-Chip (RoC) micromodel filled with two immiscible fluids. This study provides novel insights into the saturation-dependency of transport and mixing in porous media. To our knowledge, this is the first reported pore-scale experiment in which the saturation topology, relative permeability, and tortuosity were kept constant and transport was studied under different dynamic conditions in a wide range of saturation. The critical role of two-phase hydrodynamic properties on non-Fickian transport and saturation-dependency of dispersion are discussed, which highlight the major flaws in parametrization of existing models.

  4. Equilibrium and kinetic models for colloid release under transient solution chemistry conditions.

    Science.gov (United States)

    Bradford, Scott A; Torkzaban, Saeed; Leij, Feike; Simunek, Jiri

    2015-10-01

    We present continuum models to describe colloid release in the subsurface during transient physicochemical conditions. Our modeling approach relates the amount of colloid release to changes in the fraction of the solid surface area that contributes to retention. Equilibrium, kinetic, equilibrium and kinetic, and two-site kinetic models were developed to describe various rates of colloid release. These models were subsequently applied to experimental colloid release datasets to investigate the influence of variations in ionic strength (IS), pH, cation exchange, colloid size, and water velocity on release. Various combinations of equilibrium and/or kinetic release models were needed to describe the experimental data depending on the transient conditions and colloid type. Release of Escherichia coli D21g was promoted by a decrease in solution IS and an increase in pH, similar to expected trends for a reduction in the secondary minimum and nanoscale chemical heterogeneity. The retention and release of 20nm carboxyl modified latex nanoparticles (NPs) were demonstrated to be more sensitive to the presence of Ca(2+) than D21g. Specifically, retention of NPs was greater than D21g in the presence of 2mM CaCl2 solution, and release of NPs only occurred after exchange of Ca(2+) by Na(+) and then a reduction in the solution IS. These findings highlight the limitations of conventional interaction energy calculations to describe colloid retention and release, and point to the need to consider other interactions (e.g., Born, steric, and/or hydration forces) and/or nanoscale heterogeneity. Temporal changes in the water velocity did not have a large influence on the release of D21g for the examined conditions. This insensitivity was likely due to factors that reduce the applied hydrodynamic torque and/or increase the resisting adhesive torque; e.g., macroscopic roughness and grain-grain contacts. Our analysis and models improve our understanding and ability to describe the amounts

  5. Solute transport in a well under slow-purge and no-purge conditions

    Science.gov (United States)

    Plummer, M. A.; Britt, S. L.; Martin-Hayden, J. M.

    2010-12-01

    Non-purge sampling techniques, such as diffusion bags and in-situ sealed samplers, offer reliable and cost-effective groundwater monitoring methods that are a step closer to the goal of real-time monitoring without pumping or sample collection. Non-purge methods are, however, not yet completely accepted because questions remain about how solute concentrations in an unpurged well relate to concentrations in the adjacent formation. To answer questions about how undisturbed well water samples compare to formation concentrations, and to provide the information necessary to interpret results from non-purge monitoring systems, we have conducted a variety of physical experiments and numerical simulations of flow and transport in and through monitoring wells under low-flow and ambient flow conditions. Previous studies of flow and transport in wells used a Darcy’s law - based continuity equation for flow, which is often justified under the strong, forced-convection flow caused by pumping or large vertical hydraulic potential gradients. In our study, we focus on systems with weakly forced convection, where density-driven free convection may be of similar strength. We therefore solved Darcy’s law for porous media domains and the Navier Stokes equations for flow in the well, and coupled solution of the flow equations to that of solute transport. To illustrate expected in-well transport behavior under low-flow conditions, we present results of three particular studies: (1) time-dependent effluent concentrations from a well purged at low-flow pumping rates, (2) solute-driven density effects in a well under ambient horizontal flow and (3) temperature-driven mixing in a shallow well subject to seasonal temperature variations. Results of the first study illustrate that assumptions about the nature of in-well flow have a significant impact on effluent concentration curves even during pumping, with Poiseuille-type flow producing more rapid removal of concentration differences

  6. The effect of bedload transport rates on bedform and planform morphological development in a laboratory meandering stream under varying flow conditions

    Science.gov (United States)

    Sullivan, C.; Good, R. G. R.; Binns, A. D.

    2017-12-01

    Sediment transport processes in streams provides valuable insight into the temporal evolution of planform and bedform geometry. The majority of previous experimental research in the literature has focused on bedload transport and corresponding bedform development in rectangular, confined channels, which does not consider planform adjustment processes in streams. In contrast, research conducted with laboratory streams having movable banks can investigate planform development in addition to bedform development, which is more representative of natural streams. The goal of this research is to explore the relationship between bedload transport rates and the morphological adjustments in meandering streams. To accomplish this, a series of experimental runs were conducted in a 5.6 m by 1.9 m river basin flume at the University of Guelph to analyze the bedload impacts on bed formations and planform adjustments in response to varying flow conditions. In total, three experimental runs were conducted: two runs using steady state conditions and one run using unsteady flow conditions in the form of a symmetrical hydrograph implementing quasi steady state flow. The runs were performed in a series of time-steps in order to monitor the evolution of the stream morphology and the bedload transport rates. Structure from motion (SfM) was utilized to capture the channel morphology after each time-step, and Agisoft PhotoScan software was used to produce digital elevation models to analyze the morphological evolution of the channel with time. Bedload transport rates were quantified using a sediment catch at the end of the flume. Although total flow volumes were similar for each run, the morphological evolution and bedload transport rates in each run varied. The observed bedload transport rates from the flume are compared with existing bedload transport formulas to assess their accuracy with respect to sediment transport in unconfined meandering channels. The measured sediment transport

  7. On the formation of sulphuric acid – amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

    Directory of Open Access Journals (Sweden)

    I. K. Ortega

    2012-10-01

    Full Text Available Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2 at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4], dimethylamine ([DMA] and trimethylamine ([TMA], temperature and relative humidity (RH. We also tested how the model results change if we assume that the clusters with two sulphuric acid and two amine molecules would act as seeds for heterogeneous nucleation of organic vapours (other than amines with higher atmospheric concentrations than sulphuric acid. The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2=KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both had

  8. Positive nondecreasing solutions for a multi-term fractional-order functional differential equation with integral conditions

    Directory of Open Access Journals (Sweden)

    Ahmed M. A. El-Sayed

    2011-12-01

    Full Text Available In this article, we prove the existence of positive nondecreasing solutions for a multi-term fractional-order functional differential equations. We consider Cauchy boundary problems with: nonlocal conditions, two-point boundary conditions, integral conditions, and deviated arguments.

  9. Reconstruction of Oryza sativa indica Genome Scale Metabolic Model and Its Responses to Varying RuBisCO Activity, Light Intensity, and Enzymatic Cost Conditions

    Directory of Open Access Journals (Sweden)

    Ankita Chatterjee

    2017-11-01

    Full Text Available To combat decrease in rice productivity under different stresses, an understanding of rice metabolism is needed. Though there are different genome scale metabolic models (GSMs of Oryza sativa japonica, no GSM with gene-protein-reaction association exist for Oryza sativa indica. Here, we report a GSM, OSI1136 of O.s. indica, which includes 3602 genes and 1136 metabolic reactions and transporters distributed across the cytosol, mitochondrion, peroxisome, and chloroplast compartments. Flux balance analysis of the model showed that for varying RuBisCO activity (Vc/Vo (i the activity of the chloroplastic malate valve increases to transport reducing equivalents out of the chloroplast under increased photorespiratory conditions and (ii glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase can act as source of cytosolic ATP under decreased photorespiration. Under increasing light conditions we observed metabolic flexibility, involving photorespiration, chloroplastic triose phosphate and the dicarboxylate transporters of the chloroplast and mitochondrion for redox and ATP exchanges across the intracellular compartments. Simulations under different enzymatic cost conditions revealed (i participation of peroxisomal glutathione-ascorbate cycle in photorespiratory H2O2 metabolism (ii different modes of the chloroplastic triose phosphate transporters and malate valve, and (iii two possible modes of chloroplastic Glu–Gln transporter which were related with the activity of chloroplastic and cytosolic isoforms of glutamine synthetase. Altogether, our results provide new insights into plant metabolism.

  10. Demonstration of TEG-powered wireless autonomous transducer solution for condition monitoring in industrial environment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ziyang; Patrascu, Mihai; Su, Jiale; Vullers, Ruud J.M. [imec the Netherlands, Eindhoven (Netherlands)

    2011-07-01

    Imec/Holst Centre focuses on the development of wireless autonomous transducer solution, which is poised to bring about huge impact in the sectors of health care, machinery, transportation and energy, etc. In this paper, we first showcase a TEG-powered demonstration for condition monitoring in industrial environment. Composing of sensor-actuator, front-end interface, digital signal processing unit and radio, the developed wireless sensor node can monitor the changing operating condition, i.e. the loading on a rolling-element bearing, on a rotating shaft. The use of a specially designed TEG, working in tandem with an energy storage device, can significantly improve the energy autonomy of the condition monitoring system as a whole. The different components in the demonstration are presented. Subsequently, the experimental results of vibration signature analysis are exhibited. On one hand, the presented demonstration sheds light on the huge potential of thermoelectric energy harvesting to achieve energy autonomy. On the other hand, it also points to the aspects that are in need of further development, namely miniaturization and cost reduction of energy harvesters. Aimed at the delivery of cost-effective miniaturized thermoelectric harvesting devices, imec/Holst Centre has been tackling with the relevant challenges by resorting to, but not limited to, its expertise in micromachining. An update on the latest research results is subsequently given with regard to various micromachined thermoelectric devices, fully fledged wearable TEGs with custom designed package and thermoelectric material property optimization. (orig.)

  11. Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

    Science.gov (United States)

    Liu, Junzhuo; Vyverman, Wim

    2015-03-01

    The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Optimizing an Investment Solution in Conditions of Uncertainty and Risk as a Multicriterial Task

    Directory of Open Access Journals (Sweden)

    Kotsyuba Oleksiy S.

    2017-10-01

    Full Text Available The article is concerned with the methodology for optimizing investment decisions in conditions of uncertainty and risk. The subject area of the study relates, first of all, to real investment. The problem of modeling an optimal investment solution is considered to be a multicriterial task. Also, the constructive part of the publication is based on the position that the multicriteriality of objectives of investment projecting is the result, first, of the complex nature of the category of economic attractiveness (efficiency of real investment, and secondly, of the need to take into account the risk factor, which is a vector measure, in the preparation of an investment solution. An attempt has been made to develop an instrumentarium to optimize investment decisions in a situation of uncertainty and the risk it engenders, based on the use of roll-up of the local criteria. As a result of its implementation, a model has been proposed, which has the advantage that it takes into account, to a greater extent than is the case for standardized roll-up options, the contensive and formal features of the local (detailed criteria.

  13. Treatment and conditioning of radioactive waste solution by natural clay minerals

    International Nuclear Information System (INIS)

    El-Dessouky, M.I.; El-Massry, E.H.; Khalifa, S.M.; Aly, H.F.

    1999-01-01

    Natural inorganic exchangers. Was used to remove caesium, cobalt and europium using zinc sulfate as coagulant also different clay minerals. These calys include, feldrspare, aswanly, bentionite, hematite, mud, calcite, basalt, magnetite, kaoline sand stone, limonite and sand. The factros affecting the removal process namely PH, particle size, temperature and weight of the clay have been studied. Highest removal for Cs-137, Co-60 and Eu-152 and 154 was achived by asswanly and bentonite. Sand stone is more effective than the other clays. Removal of Cs-137 from low level waste solution is in the order the sequence, aswanly (85.5%)> bentonite (82.2%)> sandstone (65.4%). Solidified cement products have been evaluated to determine optimum conditions of mixing most sludges contained clays by testing mechanical strength and leaching rates of the waste products. The solidified waste forms were found more acceptable for handing, storage and ultimate disposal

  14. Effects of variations in hydraulic conductivity and flow conditions on groundwater flow and solute transport in peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Kellner, Erik [Dept. of Forest Ecology, Univ. of Helsinki (Finland)

    2007-02-15

    In this report it is examined to what extent the variation in hydraulic conductivity within a peatland and adjoining sediments would affect the flow patterns within it under some certain hydraulic-head gradients and other certain border conditions. The first part of the report contains a short review of organic and mineral-soil sediment types and characteristics and what we know about present peatlands and underlying sediments in the SKB investigation areas today. In the next part, a 2-dimensional model is used to simulate flows and transports in different settings of a peatland, with the objective of studying the effects of some particular factors: 1. The magnitude of the hydraulic conductivity of the peat and of underlying layers. 2. Presence and positions of cracks in underlying clay layers. 3. Anisotropy and heterogeneity in peat hydraulic conductivity. 4. The size of the water recharge at the peatland surface. 5. The seasonal variation of the water recharge. The modelling results show that the importance of flow direction decreases with decreasing hydraulic conductivity in the peatland. This occurs as the convective flux is slowed down and the transport is taken over by the diffusive flux. Because the lowest hydraulic conductivity layer to large extent determines the size of the flow, presence of a low-conductivity layer, such as a layer of clay, is an important factor. Presence of cracks in such tight layers can increase the transport of solutes into the peat. The highest inflow rates are reached when such cracks occur in discharge areas with strong upward flow. On the other hand, a conservative solute can spread efficiently if there is a crack in low-flow locations. The effect of anisotropy is found to be small, partly because the horizontal gradients become smaller as distances are larger. The effect of layers with high or low permeability varies depending on the location and the prevailing gradients. One tight layer has a strong effect on the flow pattern

  15. Effects of variations in hydraulic conductivity and flow conditions on groundwater flow and solute transport in peatlands

    International Nuclear Information System (INIS)

    Kellner, Erik

    2007-02-01

    In this report it is examined to what extent the variation in hydraulic conductivity within a peatland and adjoining sediments would affect the flow patterns within it under some certain hydraulic-head gradients and other certain border conditions. The first part of the report contains a short review of organic and mineral-soil sediment types and characteristics and what we know about present peatlands and underlying sediments in the SKB investigation areas today. In the next part, a 2-dimensional model is used to simulate flows and transports in different settings of a peatland, with the objective of studying the effects of some particular factors: 1. The magnitude of the hydraulic conductivity of the peat and of underlying layers. 2. Presence and positions of cracks in underlying clay layers. 3. Anisotropy and heterogeneity in peat hydraulic conductivity. 4. The size of the water recharge at the peatland surface. 5. The seasonal variation of the water recharge. The modelling results show that the importance of flow direction decreases with decreasing hydraulic conductivity in the peatland. This occurs as the convective flux is slowed down and the transport is taken over by the diffusive flux. Because the lowest hydraulic conductivity layer to large extent determines the size of the flow, presence of a low-conductivity layer, such as a layer of clay, is an important factor. Presence of cracks in such tight layers can increase the transport of solutes into the peat. The highest inflow rates are reached when such cracks occur in discharge areas with strong upward flow. On the other hand, a conservative solute can spread efficiently if there is a crack in low-flow locations. The effect of anisotropy is found to be small, partly because the horizontal gradients become smaller as distances are larger. The effect of layers with high or low permeability varies depending on the location and the prevailing gradients. One tight layer has a strong effect on the flow pattern

  16. A Quantitative Study of Tethered Chains in Various Solution Conditions Using Langmuir Diblock Copolymer Monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Kent, Michael S.

    1999-08-13

    This article summarizes our investigations of tethered chain systems using Langmuir monolayer of polydimethysiloxane-poly styrene (PDMS-PS) diblock copolymers on organic liquids. In this system, the PDMS block adsorbs to the air surface while the PS block dangles into the subphase liquid. The air surface can be made either repulsive or attractive for the tethered PS chain segments by choosing a subphase liquid which has a surface tension lower or greater than that of PS, respectively. The segment profile of the PS block is determined by neutron reflection as a function of the surface density, the molecular weights of the PS and PDMS blocks, and the solution conditions. We cover the range of reduced surface density (SIGMA) characteristic of the large body of data in the literature for systems of chains tethered onto solid surfaces from dilute solution in good or theta solvent conditions (SIGMA < 12). We emphasize quantitative comparisons with analytical profile forms and scaling predictions. We find that the strong-stretching limit invoked in analytical SCF and scaling theories is not valid over this Z range. On the other hand, over a large portion of this range (SIGMA < 5) tethered layers are well described by a renormalization group theory addressing weakly interacting or noninteracting chains. Simultaneous with the study of the profile form, the free energy of the chains is examined through the surface tension. A strong increase in the surface pressure is observed with increasing surface density which determines the maximum surface density which can be achieved. This apparently nonequilibrium effect is attributed to steric interactions and limited lateral interpenetration. This effect may explain several outstanding discrepancies regarding the adsorption of end-functionalized chains and diblock copolymers onto solid surfaces.

  17. A Semilinear Wave Equation with a Boundary Condition of Many-Point Type: Global Existence and Stability of Weak Solutions

    Directory of Open Access Journals (Sweden)

    Giai Giang Vo

    2015-01-01

    Full Text Available This paper is devoted to the study of a wave equation with a boundary condition of many-point type. The existence of weak solutions is proved by using the Galerkin method. Also, the uniqueness and the stability of solutions are established.

  18. Seed banks as a source of vegetation regeneration to support the recovery of degraded rivers: A comparison of river reaches of varying condition.

    Science.gov (United States)

    O'Donnell, Jessica; Fryirs, Kirstie A; Leishman, Michelle R

    2016-01-15

    Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation of many rivers. This research compares for river reaches of varying condition, the potential for seed banks to support geomorphic river recovery through vegetation regeneration. Seven river reaches in the lower Hunter catchment of south-eastern Australia were assessed as being in poor, moderate, or good condition, based on geomorphic and ecological indicators. Seed bank composition within the channel and floodplain (determined in a seedling emergence study) was compared to standing vegetation. Seed bank potential for supporting geomorphic recovery was assessed by measuring native species richness, and the abundance of different plant growth forms, with consideration of the roles played by different growth forms in geomorphic adjustment. The exotic seed bank was considered a limiting factor for achieving ecological restoration goals, and similarly analysed. Seed bank native species richness was comparable between the reaches, and regardless of condition, early successional and pioneer herbs, sedges, grasses and rushes dominated the seed bank. The capacity for these growth forms to colonise and stabilise non-cohesive sediments and initiate biogeomorphic succession, indicates high potential for the seed banks of even highly degraded reaches to contribute to geomorphic river recovery. However, exotic propagules increasingly dominated the seed banks of moderate and poor condition reaches and reflected increasing encroachment by terrestrial exotic vegetation associated with riparian degradation. As the degree of riparian degradation increases, the resources required to control the regeneration of exotic species will similarly increase, if seed bank-based regeneration is to contribute to both geomorphic and ecological restoration goals. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. A method comparison of total and HMW adiponectin: HMW/total adiponectin ratio varies versus total adiponectin, independent of clinical condition.

    Science.gov (United States)

    van Andel, Merel; Drent, Madeleine L; van Herwaarden, Antonius E; Ackermans, Mariëtte T; Heijboer, Annemieke C

    2017-02-01

    Total and high-molecular-weight (HMW) adiponectin have been associated with endocrine and cardiovascular pathology. As no gold standard is available, the discussion about biological relevance of isoforms is complicated. In our study we perform a method comparison between two commercially available assays measuring HMW and total adiponectin, in various patient groups, thus contributing further to this discussion. We determined levels of HMW and total adiponectin using assays by Lumipulse® and Millipore® respectively, in 126 patients with different clinical characteristics (n=29 healthy volunteers, n=22 dialysis patients, n=25 elderly with body mass index (BMI) LUMIPULSE ∗0.5-0.9=total adiponectin MILLIPORE , albeit with significant deviation from linearity (p<0.001). Pearson's correlation was R=0.987 (p=0.000). No significant differences between patient groups were observed (p=0.190). The HMW/total adiponectin ratio varies with total adiponectin concentration independent of clinical conditions studied. Our results imply that total and HMW adiponectin have similar utility when assessing adiponectin levels in blood, as the ratio is independent of clinical condition. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Solutions to the Cosmic Initial Entropy Problem without Equilibrium Initial Conditions

    Directory of Open Access Journals (Sweden)

    Vihan M. Patel

    2017-08-01

    Full Text Available The entropy of the observable universe is increasing. Thus, at earlier times the entropy was lower. However, the cosmic microwave background radiation reveals an apparently high entropy universe close to thermal and chemical equilibrium. A two-part solution to this cosmic initial entropy problem is proposed. Following Penrose, we argue that the evenly distributed matter of the early universe is equivalent to low gravitational entropy. There are two competing explanations for how this initial low gravitational entropy comes about. (1 Inflation and baryogenesis produce a virtually homogeneous distribution of matter with a low gravitational entropy. (2 Dissatisfied with explaining a low gravitational entropy as the product of a ‘special’ scalar field, some theorists argue (following Boltzmann for a “more natural” initial condition in which the entire universe is in an initial equilibrium state of maximum entropy. In this equilibrium model, our observable universe is an unusual low entropy fluctuation embedded in a high entropy universe. The anthropic principle and the fluctuation theorem suggest that this low entropy region should be as small as possible and have as large an entropy as possible, consistent with our existence. However, our low entropy universe is much larger than needed to produce observers, and we see no evidence for an embedding in a higher entropy background. The initial conditions of inflationary models are as natural as the equilibrium background favored by many theorists.

  1. Effects of Varying RedoxConditions on Natural Attenuation of Inorganic Contaminants from the D-Area Coal Pile Runoff Basin (U)

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D

    2004-05-30

    The objective of this study was to provide geochemical parameters to characterize the D-Area Coal Pile Runoff Basin (DCPRB) sediment as a potential source term. It is anticipated that the measured values will be used in risk calculations and will provide additional technical support for imposing Monitored Natural Attenuation at D-Area. This study provides a detailed evaluation of the DCPRB sediment and is part of another study that quantified the Monitored Natural Attenuation of inorganic contaminants more broadly at the D-Area Expanded Operable Unit, which includes the DCPRB (Powell et al. 2004). Distribution coefficients (K{sub d} values; a solid to liquid contaminant concentration ratio) and the Potentially Leachable Fraction (the percent of the total contaminant concentration in the sediment that can likely contribute to a contaminant plume) were measured in a DCPRB sediment as a function of redox conditions. Redox conditions at the DCPRB are expected to vary greatly as the system undergoes varying drying and flooding conditions. Conservative values; K{sub d} values that err on the side of being too low and Potentially Leachable Fraction values that err on the side of being too high, are presented. The K{sub d} values are high compared to conservative literature values, and underscores the importance of measuring site-specific values to provide estimates of sediments natural attenuation/sorption capacities. The Potentially Leachable Fraction indicates that as little as 27% of the As, but all of the Cu and Tl will be part of the source term. In the case of the As, the remaining 83% will likely never leach out of the sediment, thereby providing a form of natural attenuation. Importantly, Be, Cr, Cu, Ni, and V concentrations in the sediment were less-than twice background levels, indicating this sediment was not a potential source for these contaminants. K{sub d} values generally increased significantly (As, Cd, Co, Cr, Cu, Ni, Se, and Tl) when the sediment was

  2. Evaluation of Enzymatically Modified Soy Protein Isolate Film Forming Solution and Film at Different Manufacturing Conditions.

    Science.gov (United States)

    Mohammad Zadeh, Elham; O'Keefe, Sean F; Kim, Young-Teck; Cho, Jin-Hun

    2018-04-01

    The effects of transglutaminase on soy protein isolate (SPI) film forming solution and films were investigated by rheological behavior and physicochemical properties based on different manufacturing conditions (enzyme treatments, enzyme incubation times, and protein denaturation temperatures). Enzymatic crosslinking reaction and changes in molecular weight distribution were confirmed by viscosity measurement and SDS-PAGE, respectively, compared to 2 controls: the nonenzyme treated and the deactivated enzyme treated. Films treated with both the enzyme and the deactivated enzyme showed significant increase in tensile strength (TS), percent elongation (%E), and initial contact angle of films compared to the nonenzyme control film due to the bulk stabilizers in the commercial enzyme. Water absorption property, protein solubility, Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopy revealed that enzyme treated SPI film matrix in the molecular structure level, resulted in the changes in physicochemical properties. Based on our observation, the enzymatic treatment at appropriate conditions is a practical and feasible way to control the physical properties of protein based biopolymeric film for many different scientific and industrial areas. Enzymes can make bridges selectively among different amino acids in the structure of protein matrix. Therefore, protein network is changed after enzyme treatment. The behavior of biopolymeric materials is dependent on the network structure to be suitable in different applications such as bioplastics applied in food and pharmaceutical products. In the current research, transglutaminase, as an enzyme, applied in soy protein matrix in different types of forms, activated and deactivated, and different preparation conditions to investigate its effects on different properties of the new bioplastic film. © 2018 Institute of Food Technologists®.

  3. Necessary and sufficient conditions for nonoscillatory solutions of impulsive delay differential equations

    Directory of Open Access Journals (Sweden)

    Shao Yuan Huang

    2013-07-01

    Full Text Available Monotonicity of solutions is an important property in the investigation of oscillatory behaviors of differential equations. A number of papers provide some existence criteria for eventually positive increasing solutions. However, relatively little attention is paid to eventually positive solutions that are also eventually decreasing solutions. For this reason, we establish several new and sharp oscillatory criteria for impulsive functional differential equations from this viewpoint.

  4. varying elastic parameters distributions

    KAUST Repository

    Moussawi, Ali

    2014-12-01

    The experimental identication of mechanical properties is crucial in mechanics for understanding material behavior and for the development of numerical models. Classical identi cation procedures employ standard shaped specimens, assume that the mechanical elds in the object are homogeneous, and recover global properties. Thus, multiple tests are required for full characterization of a heterogeneous object, leading to a time consuming and costly process. The development of non-contact, full- eld measurement techniques from which complex kinematic elds can be recorded has opened the door to a new way of thinking. From the identi cation point of view, suitable methods can be used to process these complex kinematic elds in order to recover multiple spatially varying parameters through one test or a few tests. The requirement is the development of identi cation techniques that can process these complex experimental data. This thesis introduces a novel identi cation technique called the constitutive compatibility method. The key idea is to de ne stresses as compatible with the observed kinematic eld through the chosen class of constitutive equation, making possible the uncoupling of the identi cation of stress from the identi cation of the material parameters. This uncoupling leads to parametrized solutions in cases where 5 the solution is non-unique (due to unknown traction boundary conditions) as demonstrated on 2D numerical examples. First the theory is outlined and the method is demonstrated in 2D applications. Second, the method is implemented within a domain decomposition framework in order to reduce the cost for processing very large problems. Finally, it is extended to 3D numerical examples. Promising results are shown for 2D and 3D problems.

  5. Sparse grid spectral methods for the numerical solution of partial differential equations with periodic boundary conditions

    International Nuclear Information System (INIS)

    Kupka, F.

    1997-11-01

    This thesis deals with the extension of sparse grid techniques to spectral methods for the solution of partial differential equations with periodic boundary conditions. A review on boundary and initial-boundary value problems and a discussion on numerical resolution is used to motivate this research. Spectral methods are introduced by projection techniques, and by three model problems: the stationary and the transient Helmholtz equations, and the linear advection equation. The approximation theory on the hyperbolic cross is reviewed and its close relation to sparse grids is demonstrated. This approach extends to non-periodic problems. Various Sobolev spaces with dominant mixed derivative are introduced to provide error estimates for Fourier approximation and interpolation on the hyperbolic cross and on sparse grids by means of Sobolev norms. The theorems are immediately applicable to the stability and convergence analysis of sparse grid spectral methods. This is explicitly demonstrated for the three model problems. A variant of the von Neumann condition is introduced to simplify the stability analysis of the time-dependent model problems. The discrete Fourier transformation on sparse grids is discussed together with its software implementation. Results on numerical experiments are used to illustrate the performance of the new method with respect to the smoothness properties of each example. The potential of the method in mathematical modelling is estimated and generalizations to other sparse grid methods are suggested. The appendix includes a complete Fortran90 program to solve the linear advection equation by the sparse grid Fourier collocation method and a third-order Runge-Kutta routine for integration in time. (author)

  6. Assessing and monitoring the effects of filter material amendments on the biophysicochemical properties during composting of solid winery waste under open field and varying climatic conditions.

    Science.gov (United States)

    Mtimkulu, Y; Meyer, A H; Mulidzi, A R; Shange, P L; Nchu, F

    2017-01-01

    Waste management in winery and distillery industries faces numerous disposal challenges as large volumes of both liquid and solid waste by-products are generated yearly during cellar practices. Composting has been suggested as a feasible option to beneficiate solid organic waste. This incentivized the quest for efficient composting protocols to be put in place. The objective of this study was to experiment with different composting strategies for spent winery solid waste. Compost materials consisting of chopped pruning grape stalks, skins, seed and spent wine filter material consisting of a mixture of organic and inorganic expend ingredients were mixed in compost heaps. The filter material component varied (in percentage) among five treatments: T1 (40%) lined, T2 (20%) lined, T3 (0%) lined, T4 (40%) ground material, lined and T5 (40%) unlined. Composting was allowed to proceed under open field conditions over 12months, from autumn to summer. Indicators such as temperature, moisture, enzyme activities, microbial counts, pH, and C/N ratio, were recorded. Generally, season (df=3, 16, Pwinery solid waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Spectral boundary conditions and solitonic solutions in a classical Sellmeier dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Belgiorno, F. [Politecnico di Milano, Dipartimento di Matematica, Milan (Italy); INdAM-GNFM, Rome (Italy); INFN, Milan (Italy); Cacciatori, S.L. [Universita dell' Insubria, Department of Science and High Technology, Como (Italy); INFN, Milan (Italy); Vigano, A. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy)

    2017-06-15

    Electromagnetic field interactions in a dielectric medium represent a longstanding field of investigation, both at the classical level and at the quantum one. We propose a 1+1 dimensional toy-model which consists of an half-line filling dielectric medium, with the aim to set up a simplified situation where technicalities related to gauge invariance and, as a consequence, physics of constrained systems are avoided, and still interesting features appear. In particular, we simulate the electromagnetic field and the polarization field by means of two coupled scalar fields φ, ψ, respectively, in a Hopfield-like model. We find that, in order to obtain a physically meaningful behavior for the model, one has to introduce spectral boundary conditions depending on the particle spectrum one is dealing with. This is the first interesting achievement of our analysis. The second relevant achievement is that, by introducing a nonlinear contribution in the polarization field ψ, with the aim of mimicking a third order nonlinearity in a nonlinear dielectric, we obtain solitonic solutions in the Hopfield model framework, whose classical behavior is analyzed too. (orig.)

  8. Radiolysis of pyridoxine (vitamin B6) in aqueous solution under different conditions

    International Nuclear Information System (INIS)

    Albarran, Guadalupe; Ramirez-Cahero, Fernando; Aliev, Roustam

    2008-01-01

    Aqueous solutions of pyridoxine (1 mM) without or with additive of K 3 [Fe(CN) 6 ] (2.5 mM) were gamma-irradiated at different doses and dose rate of 2.16 kGy/h in the absence of air, in the presence of air or by their saturation with N 2 O. The radiolytic products were analyzed with HPLC, mass spectrometry and UV spectroscopy. 2,4,5-Trihydroxymethyl-3-pyridinol, pyridoxal, isopyridoxal and 6-hydroxypyridoxine were formed by radiolysis in the absence of K 3 [Fe(CN) 6 ], and their concentrations were much higher in samples saturated with N 2 O. Pyridoxi-3,6-quinone was found by radiolysis under all the above-mentioned conditions but only in the presence of K 3 [Fe(CN) 6 ]. Besides, the pyridoxal formation increased in the presence of this oxidizing agent. G values of pyridoxal formation and pyridoxine degradation were quantified. Some details of the radiolytic product formation were discussed

  9. Radiolysis of pyridoxine (vitamin B{sub 6}) in aqueous solution under different conditions

    Energy Technology Data Exchange (ETDEWEB)

    Albarran, Guadalupe [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico 04510, D.F. (Mexico)], E-mail: albarran@nucleares.unam.mx; Ramirez-Cahero, Fernando; Aliev, Roustam [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico 04510, D.F. (Mexico)

    2008-05-15

    Aqueous solutions of pyridoxine (1 mM) without or with additive of K{sub 3}[Fe(CN){sub 6}] (2.5 mM) were gamma-irradiated at different doses and dose rate of 2.16 kGy/h in the absence of air, in the presence of air or by their saturation with N{sub 2}O. The radiolytic products were analyzed with HPLC, mass spectrometry and UV spectroscopy. 2,4,5-Trihydroxymethyl-3-pyridinol, pyridoxal, isopyridoxal and 6-hydroxypyridoxine were formed by radiolysis in the absence of K{sub 3}[Fe(CN){sub 6}], and their concentrations were much higher in samples saturated with N{sub 2}O. Pyridoxi-3,6-quinone was found by radiolysis under all the above-mentioned conditions but only in the presence of K{sub 3}[Fe(CN){sub 6}]. Besides, the pyridoxal formation increased in the presence of this oxidizing agent. G values of pyridoxal formation and pyridoxine degradation were quantified. Some details of the radiolytic product formation were discussed.

  10. Light-induced magnetoresistance in solution-processed planar hybrid devices measured under ambient conditions

    Directory of Open Access Journals (Sweden)

    Sreetama Banerjee

    2017-07-01

    Full Text Available We report light-induced negative organic magnetoresistance (OMAR measured in ambient atmosphere in solution-processed 6,13-bis(triisopropylsilylethynylpentacene (TIPS-pentacene planar hybrid devices with two different device architectures. Hybrid electronic devices with trench-isolated electrodes (HED-TIE having a channel length of ca. 100 nm fabricated in this work and, for comparison, commercially available pre-structured organic field-effect transistor (OFET substrates with a channel length of 20 µm were used. The magnitude of the photocurrent as well as the magnetoresistance was found to be higher for the HED-TIE devices because of the much smaller channel length of these devices compared to the OFETs. We attribute the observed light-induced negative magnetoresistance in TIPS-pentacene to the presence of electron–hole pairs under illumination as the magnetoresistive effect scales with the photocurrent. The magnetoresistance effect was found to diminish over time under ambient conditions compared to a freshly prepared sample. We propose that the much faster degradation of the magnetoresistance effect as compared to the photocurrent was due to the incorporation of water molecules in the TIPS-pentacene film.

  11. Light-induced magnetoresistance in solution-processed planar hybrid devices measured under ambient conditions.

    Science.gov (United States)

    Banerjee, Sreetama; Bülz, Daniel; Reuter, Danny; Hiller, Karla; Zahn, Dietrich R T; Salvan, Georgeta

    2017-01-01

    We report light-induced negative organic magnetoresistance (OMAR) measured in ambient atmosphere in solution-processed 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) planar hybrid devices with two different device architectures. Hybrid electronic devices with trench-isolated electrodes (HED-TIE) having a channel length of ca. 100 nm fabricated in this work and, for comparison, commercially available pre-structured organic field-effect transistor (OFET) substrates with a channel length of 20 µm were used. The magnitude of the photocurrent as well as the magnetoresistance was found to be higher for the HED-TIE devices because of the much smaller channel length of these devices compared to the OFETs. We attribute the observed light-induced negative magnetoresistance in TIPS-pentacene to the presence of electron-hole pairs under illumination as the magnetoresistive effect scales with the photocurrent. The magnetoresistance effect was found to diminish over time under ambient conditions compared to a freshly prepared sample. We propose that the much faster degradation of the magnetoresistance effect as compared to the photocurrent was due to the incorporation of water molecules in the TIPS-pentacene film.

  12. Variability of the morphometric features of Calliphora vicina (Diptera, Calliphoridae under the varying and constant micro-climatic condi-tions

    Directory of Open Access Journals (Sweden)

    L. I. Faly

    2013-03-01

    Full Text Available Variability of the main morphometric features of imago flies Calliphora vicina R.-D. (Diptera, Calliphoridae of two samples was studied. First sample consists of individuals caught in the wild (park ecosystems of Dnipropetrovsk, the second one – specimens cultured in the laboratory under the constant temperature and humidity. Possible using of C. vicina R.-D. as a bioindicator of anthropogenic factors is analysed. Environmental factors may act as the stimulators of adaptive changes in physiological functions, as the constraints that cause impossibility of the existence of certain species in particular conditions, and as modifiers that determine the morpho- anatomical and physiological changes in organisms. The most significant differences between studied samples were found for the width (“laboratory” individuals are characterized by larger head size and for the length of limbs segments. The fluctuating range of the head width in specimens collected in the wild is much wider, due to the heterogeneity of the micro-climatic conditions of the larvae development and trophic resources. Maximal negative asymmetry of the head width is observed in individuals C. vicina R.-D. of the “natural” sample as compared with “laboratory” individuals. Among imagoes caught in the wild the individuals with a relatively wide head are dominated, as evidenced by the large positive value of kurtosis. At the same time, the distribution of values in “laboratory” individuals is almost normal. In adults bred in the laboratory the shortening of segments of the leg pair I is observed in comparison with the individuals of “natural” sample. Similar results were recorded for other insect groups cultivated in a laboratory. For most other linear measurements of the C. vicina R.-D. body the differences between samples are not registered. Ephemeral existence of the substrate of blow flies leads to higher prevailing evolutionary adaptation of species to varying

  13. Fate of cadmium at the soil-solution interface: a thermodynamic study as influenced by varying pH at South 24 Parganas, West Bengal, India.

    Science.gov (United States)

    Karak, Tanmoy; Paul, Ranjit Kumar; Das, Sampa; Das, Dilip K; Dutta, Amrit Kumar; Boruah, Romesh K

    2015-11-01

    A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18' 48.02″ N and 88° 39' 29.0″ E) and Lakshmikantapur (22° 06' 16.61″ N and 88° 19' 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5-100 mg L(-1)). The average rate coefficient (kavg) and half-life (t1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t 1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (Ea) values, Cd sorption in acidic pH (14.76±0.29 to 64.45±4.50 kJ mol(-1)) is a surface control phenomenon and in alkaline pH (9.33±0.09 to 44.60±2.01 kJ mol(-1)) is a diffusion control phenomenon The enthalpy of activation (ΔH∓) values were found to be between 7.28 and 61.73 kJ mol(-1). Additionally, higher positive energy of activation (ΔG∓) values (46.82±2.01 to 94.47±2.36 kJ mol(-1)) suggested that there is an energy barrier for product formation.

  14. Conservadorismo condicional: estudo a partir de variáveis econômicas Conditional conservatism: a study based on economic variables

    Directory of Open Access Journals (Sweden)

    Rafael de Lacerda Moreira

    2010-12-01

    Full Text Available A Contabilidade, na perspectiva da abordagem da informação, volta-se à utilidade da informação. O Conservadorismo Condicional está ligado à tendência de a Contabilidade exigir um maior grau de verificação das boas notícias para reconhecê-las no resultado em relação ao grau de verificação das más notícias. Em face das preocupações referentes à qualidade da informação contábil, o objetivo deste artigo consiste em analisar o reflexo do Conservadorismo Condicional no resultado contábil a partir de variáveis econômicas. O estudo utiliza o Modelo Reverso de Lucros Associados a Retornos (BASU, 1997 e o modelo proposto por Kahn e Watts (2009, que analisam a relação entre as variáveis lucro contábil e retorno econômico, utilizando os valores dos retornos positivos e negativos como proxy de boas e más notícias, e outras variáveis largamente aceitas na avaliação do conservadorismo. Para tanto, foram estimados os modelos estatísticos para uma amostra de 96 empresas para o período de 2005 a 2007 partindo de informações anuais disponíveis no Economática® e dados reportados em notas explicativas. Com o objetivo de selecionar um evento econômico que pode impactar no reconhecimento assimétrico do resultado econômico, decidiu-se comparar os resultados entre empresas listadas nos níveis de governança da Bovespa com as demais empresas. Os resultados obtidos confirmam a hipótese de utilização de conservadorismo condicional na mensuração do resultado das companhias da amostra. A diferenciação positiva quanto ao grau de conservadorismo para as empresas que aderiram aos níveis de governança não são conclusivas, visto que os modelos apresentaram resultados dispersos. As variáveis econômicas criam vantagens quando as más notícias não podem ser tão claramente visíveis nas Demonstrações Contábeis, podendo diminuir os resultados futuros esperados.Accounting from an information perspective looks at the

  15. Correction of Hemodynamics with Hypertonic Sodium Chloride Solution in Critical Conditions

    Directory of Open Access Journals (Sweden)

    P. S. Zhbannikov

    2007-01-01

    Full Text Available Objective: to assess the capabilities of small-volume hypertonic infusion in the context of early goal-directed therapy for critical conditions in surgical patients.Subjects and methods. Twenty-nine patients (SAPS II 47.5±6.81 scores operated on for generalized peritonitis (n=24 or severe concomitant injury with damages to chest and/or abdominal organs (n=5 who had the clinical and laboratory signs of a systemic inflammatory reaction were intravenously injected 4 ml/kg of 7.5% of hypertonic sodium chloride solution (HS and colloidal solution, followed by infusion and, if indicated, inotropic maintenance of hemodynamics for 6 hours in order to achieve the goal vales of mean blood pressure (BP, central venous pressure (CVP, central venous blood oxygen saturation (ScvO2, and diuresis. Plasma concentrations of sodium, chlorine, and lactate, acid-base balance, and osmotic blood pressure were monitored.Results. The patients were found to have infusion therapy-refractory critical arterial hypotension, low ScvO2, and oliguria before small-volume circulation maintenance. In all the patients, HS infusion originally caused a rapid rise in BP up to the goal value, with its further colloid infusion maintenance requiring additional dopamine infusion in 12 patients and red blood cell transfusion in 3. This could stabilize over 6 hours BP at the required level in 25 patients, in 9 of whom CVP only approximated the goal value. All the patients were found to have a significant increase in ScvO2 up to an average of 68% in response to HP infusion after 30—60 minutes; in 14 out of them ScvO2 exceeded 70%. By hour 6, ScvO2 stabilized at its goal level in 23 (79% examinees. Administration of HS caused a significantly increased diuresis. In patients with recovered renal function, the observed hypernatremia, hyperchloremia with hyperchloremic acidosis were transient.Conclusion. The results of the study show it possible to include small-volume hypertonic infusion at

  16. Necessary and Sufficient Conditions for the Existence of Positive Solution for Singular Boundary Value Problems on Time Scales

    Directory of Open Access Journals (Sweden)

    Zhang Xuemei

    2009-01-01

    Full Text Available By constructing available upper and lower solutions and combining the Schauder's fixed point theorem with maximum principle, this paper establishes sufficient and necessary conditions to guarantee the existence of as well as positive solutions for a class of singular boundary value problems on time scales. The results significantly extend and improve many known results for both the continuous case and more general time scales. We illustrate our results by one example.

  17. Existence and Analytic Approximation of Solutions of Duffing Type Nonlinear Integro-Differential Equation with Integral Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Alsaedi Ahmed

    2009-01-01

    Full Text Available A generalized quasilinearization technique is developed to obtain a sequence of approximate solutions converging monotonically and quadratically to a unique solution of a boundary value problem involving Duffing type nonlinear integro-differential equation with integral boundary conditions. The convergence of order for the sequence of iterates is also established. It is found that the work presented in this paper not only produces new results but also yields several old results in certain limits.

  18. Wear properties of Ti-13Zr-13Nb (wt.%) near β titanium alloy containing 0.5 wt.% boron in dry condition, Hank's solution and bovine serum

    International Nuclear Information System (INIS)

    Majumdar, P.; Singh, S.B.; Chakraborty, M.

    2010-01-01

    The effect of heat treatment on the microstructure, hardness and sliding wear behaviour of Ti-13Zr-13Nb (wt.%) containing 0.5 wt.% B (TZNB) has been studied and compared with that of Ti-13Zr-13Nb (wt.%) (TZN) alloy. The wear properties were tested in dry condition and in simulated body fluid (Hank's solution and bovine serum) to understand the effect of different medium on wear behaviour of the TZNB alloy. Depending on the heat treatment condition the microstructure of the alloy consisted of α/martensite and TiB in β matrix. In general, the hardness of all the heat treated samples varied in a narrow range and in most of the cases addition of boron to the TZN alloy decreased the hardness. Almost all cases, no significant variation of the wear rate in dry condition with heat treatment was observed. Compared with the wear rate in dry condition, the wear rate in Hank's solution of the all the TZNB samples increased substantially. Moreover, the wear was found to be most severe in bovine serum. Addition of boron to TZN alloy did not result in any improvement in the wear resistance in all the media studied.

  19. Global smooth solutions of 3-D null-form wave equations in exterior domains with Neumann boundary conditions

    Science.gov (United States)

    Jun, Li; Huicheng, Yin

    2018-05-01

    The paper is devoted to investigating long time behavior of smooth small data solutions to 3-D quasilinear wave equations outside of compact convex obstacles with Neumann boundary conditions. Concretely speaking, when the surface of a 3-D compact convex obstacle is smooth and the quasilinear wave equation fulfills the null condition, we prove that the smooth small data solution exists globally provided that the Neumann boundary condition on the exterior domain is given. One of the main ingredients in the current paper is the establishment of local energy decay estimates of the solution itself. As an application of the main result, the global stability to 3-D static compressible Chaplygin gases in exterior domain is shown under the initial irrotational perturbation with small amplitude.

  20. Fate of As(V)-treated nano zero-valent iron: determination of arsenic desorption potential under varying environmental conditions by phosphate extraction.

    Science.gov (United States)

    Dong, Haoran; Guan, Xiaohong; Lo, Irene M C

    2012-09-01

    Nano zero-valent iron (NZVI) offers a promising approach for arsenic remediation, but the spent NZVI with elevated arsenic content could arouse safety concerns. This study investigated the fate of As(V)-treated NZVI (As-NZVI), by examining the desorption potential of As under varying conditions. The desorption kinetics of As from As-NZVI as induced by phosphate was well described by a biphasic rate model. The effects of As(V)/NZVI mass ratio, pH, and aging time on arsenic desorption from As-NZVI by phosphate were investigated. Less arsenic desorption was observed at lower pH or higher As(V)/NZVI mass ratio, where stronger complexes (bidentate) formed between As(V) and NZVI corrosion products as indicated by FTIR analysis. Compared with the fresh As-NZVI, the amount of phosphate-extractable As significantly decreased in As-NZVI aged for 30 or 60 days. The results of the sequential extraction experiments demonstrated that a larger fraction of As was sorbed in the crystalline phases after aging, making it less susceptible to phosphate displacement. However, at pH 9, a slightly higher proportion of phosphate-extractable As was observed in the 60-day sample than in the 30-day sample. XPS results revealed the transformation of As(V) to more easily desorbed As(III) during aging and a higher As(III)/As(V) ratio in the 60-day sample at pH 9, which might have resulted in the higher desorption. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Successful transportation of human corneal endothelial tissues without cool preservation in varying Indian tropical climatic conditions and in vitro cell expansion using a novel polymer.

    Science.gov (United States)

    Rao, Srinivas K; Sudhakar, John; Parikumar, Periyasamy; Natarajan, Sundaram; Insaan, Aditya; Yoshioka, Hiroshi; Mori, Yuichi; Tsukahara, Shigeo; Baskar, Subramani; Manjunath, Sadananda Rao; Senthilkumar, Rajappa; Thamaraikannan, Paramasivam; Srinivasan, Thangavelu; Preethy, Senthilkumar; Abraham, Samuel J K

    2014-02-01

    Though the transplantation of human corneal endothelial tissue (CET) separated from cadaver cornea is in practice, its transportation has not been reported. We report the successful transportation of CET in varying Indian climatic conditions without cool preservation and the in vitro expansion of Human Corneal Endothelial Precursor Cells (HCEPCs) using a novel Thermo-reversible gelation polymer (TGP). CET from cadaver corneas (n = 67), unsuitable for transplantation, were used. In phase I, CET was transported in Basal Culture Medium (Group I) and TGP (Group II) and in Phase II, in TGP cocktail alone, from three hospitals 250-2500 km away, to a central laboratory. The transportation time ranged from 6 h to 72 h and the outdoor temperature between 20°C and 41°C. On arrival, CET were processed, cells were expanded upto 30 days in basal culture medium (Group A) and TGP scaffold (Group B). Cell viability and morphology were documented and Reverse transcription polymerase chain reaction (RT-PCR) characterization undertaken. In Phase I, TGP yielded more viable cells (0.11 × 10(6) cells) than Group I (0.04 × 10(6) cells). In Phase II, the average cell count was 5.44 × 10(4) cells. During expansion, viability of HCEPCs spheres in TGP was maintained for a longer duration. The cells from both the groups tested positive for B-3 tubulin and negative for cytokeratins K3 and K12, thereby proving them to be HCEPCs. TGP preserves the CET during transportation without cool preservation and supports in vitro expansion, with a higher yield of HCEPCs, similar to that reported in clinical studies.

  2. Successful transportation of human corneal endothelial tissues without cool preservation in varying Indian tropical climatic conditions and in vitro cell expansion using a novel polymer

    Directory of Open Access Journals (Sweden)

    Srinivas K Rao

    2014-01-01

    Full Text Available Background: Though the transplantation of human corneal endothelial tissue (CET separated from cadaver cornea is in practice, its transportation has not been reported. We report the successful transportation of CET in varying Indian climatic conditions without cool preservation and the in vitro expansion of Human Corneal Endothelial Precursor Cells (HCEPCs using a novel Thermo-reversible gelation polymer (TGP. Materials and Methods: CET from cadaver corneas (n = 67, unsuitable for transplantation, were used. In phase I, CET was transported in Basal Culture Medium (Group I and TGP (Group II and in Phase II, in TGP cocktail alone, from three hospitals 250-2500 km away, to a central laboratory. The transportation time ranged from 6 h to 72 h and the outdoor temperature between 20°C and 41°C. On arrival, CET were processed, cells were expanded upto 30 days in basal culture medium (Group A and TGP scaffold (Group B. Cell viability and morphology were documented and Reverse transcription polymerase chain reaction (RT-PCR characterization undertaken. Results: In Phase I, TGP yielded more viable cells (0.11 × 10 6 cells than Group I (0.04 × 10 6 cells. In Phase II, the average cell count was 5.44 × 10 4 cells. During expansion, viability of HCEPCs spheres in TGP was maintained for a longer duration. The cells from both the groups tested positive for B-3 tubulin and negative for cytokeratins K3 and K12, thereby proving them to be HCEPCs. Conclusion: TGP preserves the CET during transportation without cool preservation and supports in vitro expansion, with a higher yield of HCEPCs, similar to that reported in clinical studies.

  3. Two-dimensional finite element solution for the simultaneous transport of water and solutes through a nonhomogeneous aquifer under transient saturated unsaturated flow conditions

    International Nuclear Information System (INIS)

    Gureghian, A.B.

    1979-01-01

    A mathematical model of ground water transport through an aquifer is presented. The solute of interest is a metal tracer or radioactive material which may undergo decay through a sorbing unconfined aquifer. The subject is developed under the following headings: flow equation, solute equation, boundary conditions, finite element formulation, element formulation, solution scheme (flow equation, solute equation), results and discussions, water movement in a ditch drained aquifer under transient state, water and solute movement in a homogeneous and unsaturated soil, transport of 226 Ra in nonhomogeneous aquifer, tailings pond lined, and tailings pond unlined. It is concluded that this mathematical model may have a wide variety of applications. The uranium milling industry may find it useful to evaluate the hydrogeological suitability of their disposal sites. It may prove suited for the design of clay disposal ponds destined to hold hazardous liquids. It may also provide a means of estimating the long-term impact of radionuclides or other pollutants on the quality of ground water. 31 references, 9 figures, 3 tables

  4. Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions

    International Nuclear Information System (INIS)

    Reeves, T.L.; Turner, J.P.; Hasfurther, V.R.; Skinner, Q.D.

    1992-06-01

    The scope of this program is to study interacting hydrologic, geotechnical, and chemical factors affecting the behavior and disposal of combusted processed oil shale. The research combines bench-scale testing with large scale research sufficient to describe commercial scale embankment behavior. The large scale approach was accomplished by establishing five lysimeters, each 7.3 x 3.0 x 3.0 m deep, filled with processed oil shale that has been retorted and combusted by the Lurgi-Ruhrgas (Lurgi) process. Approximately 400 tons of Lurgi processed oil shale waste was provided by RBOSC to carry out this study. Research objectives were designed to evaluate hydrologic, geotechnical, and chemical properties and conditions which would affect the design and performance of large-scale embankments. The objectives of this research are: assess the unsaturated movement and redistribution of water and the development of potential saturated zones and drainage in disposed processed oil shale under natural and simulated climatic conditions; assess the unsaturated movement of solubles and major chemical constituents in disposed processed oil shale under natural and simulated climatic conditions; assess the physical and constitutive properties of the processed oil shale and determine potential changes in these properties caused by disposal and weathering by natural and simulated climatic conditions; assess the use of previously developed computer model(s) to describe the infiltration, unsaturated movement, redistribution, and drainage of water in disposed processed oil shale; evaluate the stability of field scale processed oil shale solid waste embankments using computer models

  5. Study of weak solutions for parabolic variational inequalities with nonstandard growth conditions.

    Science.gov (United States)

    Dong, Yan

    2018-01-01

    In this paper, we study the degenerate parabolic variational inequality problem in a bounded domain. First, the weak solutions of the variational inequality are defined. Second, the existence and uniqueness of the solutions in the weak sense are proved by using the penalty method and the reduction method.

  6. Straw incorporation increases crop yield and soil organic carbon sequestration but varies under different natural conditions and farming practices in China: a system analysis

    Directory of Open Access Journals (Sweden)

    X. Han

    2018-04-01

    Full Text Available Loss of soil organic carbon (SOC from agricultural soils is a key indicator of soil degradation associated with reductions in net primary productivity in crop production systems worldwide. Technically simple and locally appropriate solutions are required for farmers to increase SOC and to improve cropland management. In the last 30 years, straw incorporation (SI has gradually been implemented across China in the context of agricultural intensification and rural livelihood improvement. A meta-analysis of data published before the end of 2016 was undertaken to investigate the effects of SI on crop production and SOC sequestration. The results of 68 experimental studies throughout China in different edaphic conditions, climate regions and farming regimes were analyzed. Compared with straw removal (SR, SI significantly sequestered SOC (0–20 cm depth at the rate of 0.35 (95 % CI, 0.31–0.40 Mg C ha−1 yr−1, increased crop grain yield by 13.4 % (9.3–18.4 % and had a conversion efficiency of the incorporated straw C of 16 % ± 2 % across China. The combined SI at the rate of 3 Mg C ha−1 yr−1 with mineral fertilizer of 200–400 kg N ha−1 yr−1 was demonstrated to be the best farming practice, where crop yield increased by 32.7 % (17.9–56.4 % and SOC sequestrated by the rate of 0.85 (0.54–1.15 Mg C ha−1 yr−1. SI achieved a higher SOC sequestration rate and crop yield increment when applied to clay soils under high cropping intensities, and in areas such as northeast China where the soil is being degraded. The SOC responses were highest in the initial starting phase of SI, then subsequently declined and finally became negligible after 28–62 years. However, crop yield responses were initially low and then increased, reaching their highest level at 11–15 years after SI. Overall, our study confirmed that SI created a positive feedback loop of SOC enhancement together with

  7. Straw incorporation increases crop yield and soil organic carbon sequestration but varies under different natural conditions and farming practices in China: a system analysis

    Science.gov (United States)

    Han, Xiao; Xu, Cong; Dungait, Jennifer A. J.; Bol, Roland; Wang, Xiaojie; Wu, Wenliang; Meng, Fanqiao

    2018-04-01

    Loss of soil organic carbon (SOC) from agricultural soils is a key indicator of soil degradation associated with reductions in net primary productivity in crop production systems worldwide. Technically simple and locally appropriate solutions are required for farmers to increase SOC and to improve cropland management. In the last 30 years, straw incorporation (SI) has gradually been implemented across China in the context of agricultural intensification and rural livelihood improvement. A meta-analysis of data published before the end of 2016 was undertaken to investigate the effects of SI on crop production and SOC sequestration. The results of 68 experimental studies throughout China in different edaphic conditions, climate regions and farming regimes were analyzed. Compared with straw removal (SR), SI significantly sequestered SOC (0-20 cm depth) at the rate of 0.35 (95 % CI, 0.31-0.40) Mg C ha-1 yr-1, increased crop grain yield by 13.4 % (9.3-18.4 %) and had a conversion efficiency of the incorporated straw C of 16 % ± 2 % across China. The combined SI at the rate of 3 Mg C ha-1 yr-1 with mineral fertilizer of 200-400 kg N ha-1 yr-1 was demonstrated to be the best farming practice, where crop yield increased by 32.7 % (17.9-56.4 %) and SOC sequestrated by the rate of 0.85 (0.54-1.15) Mg C ha-1 yr-1. SI achieved a higher SOC sequestration rate and crop yield increment when applied to clay soils under high cropping intensities, and in areas such as northeast China where the soil is being degraded. The SOC responses were highest in the initial starting phase of SI, then subsequently declined and finally became negligible after 28-62 years. However, crop yield responses were initially low and then increased, reaching their highest level at 11-15 years after SI. Overall, our study confirmed that SI created a positive feedback loop of SOC enhancement together with increased crop production, and this is of great practical importance to straw management as agriculture

  8. Characterization of Skeletonema costatum Intracellular Organic Matter and Study of Nanomechanical Properties under Different Solution Conditions

    KAUST Repository

    Gutierrez, Leonardo; Aubry, Cyril; Dramas, Laure; Aimar, Pierre; Croue, Jean-Philippe

    2016-01-01

    -IOM was characterized as a mixture of polysaccharides, proteins, and lipids. Atomic force microscopy (AFM) provided crucial information of this isolate at a nanoscale resolution. HMW SKC-IOM showed highly responsive to solution chemistry: fully extended chains at low

  9. Synthesis of (U,Zr)C solid solutions under exothermic conditions

    International Nuclear Information System (INIS)

    Wang, L.L.; Moore, H.G.; Gladson, J.W.

    1993-01-01

    The reactions of forming (U,Zr)C solid solutions from their elemental components or similarly less stable reactants such as UC 2 are strongly exothermic due to the high stability of these solid solutions. A simple approach of utilizing this heat of formation energy to assist the solid solution reaction process is to intimately mix the less stable reactant powders and then pressed them into a compact. The compact is then heated to the ignition temperature of the reaction. The feasibility of this reaction method to synthesize (U,Zr)C solid solutions has been demonstrated in this study. The preliminary results also show that both the initial composition and the heating rate have a significant effect on the nature of the reaction process. As expected the degree of powder mixing was also found to affect the completeness of the reaction

  10. A charged anisotropic well-behaved Adler-Finch-Skea solution satisfying Karmarkar condition

    Science.gov (United States)

    Bhar, Piyali; Singh, Ksh. Newton; Rahaman, Farook; Pant, Neeraj; Banerjee, Sumita

    In the present paper, we discover a new well-behaved charged anisotropic solution of Einstein-Maxwell’s field equations. We ansatz the metric potential g00 of the form given by Maurya et al. (Eur. Phys. J. C 76(12) (2016) 693) with n = 2. In their paper, it is mentioned that for n = 2, the solution is not well-behaved for neutral configuration as the speed of sound is nondecreasing radially outward. However, the solution can represent a physically possible configuration with the inclusion of some net electric charge, i.e. the solution can become a well-behaved solution with decreasing sound speed radially outward for a charged configuration. Due to the inclusion of electric charge, the solution leads to a very stiff equation-of-state (EoS) with the velocity of sound at the center vr02 = 0.819, vt02 = 0.923 and the compactness parameter u = 0.823 is close to the Buchdahl limit 0.889. This stiff EoS support a compact star configuration of mass 5.418M⊙ and radius of 10.1km.

  11. Comparative estimation of inevitable endogenous ileal flow of amino acids in Pekin ducks under varying dietary or physiological conditions and their significance to nutritional requirements for amino acids.

    Science.gov (United States)

    Akinde, D O

    2017-10-01

    In 2 experiments in Pekin ducks the inevitable endogenous ileal flow (IEIF) of AA was estimated at changing intake and source of crude fiber (CF) or soybean oil (SO) level. Also the roles of dry matter intake (DMI) and BW or age as well as the proportion of IEIF in the dietary requirement for AA were studied. In experiment 1 three basal CP (20, 60, or 100 g/kg) diets were formulated containing a low CF (LCF, 30 g/kg) or high (HCF, 80 g/kg) level; achieved with cellulose supplementation. All diets were similar in every other respect including having SO content of 40 g/kg. Four floor pens of eight 85-day-old ducks were randomly allocated to each diet. Similar diets were mixed in experiment 2 but corn cob meal replaced cellulose as the fiber source. A high SO (HSO) series was also formed by increasing the SO level from 40 g/kg in the basal series to 100 g/kg. Thus the LCF series was concurrently classified as low SO (LSO) series to control SO effect. Each of the eventual 9 diets were fed to 5 floor pens of ten 65-day-old ducks. Ileal AA flow was measured after a 5 day feeding period in both experiments. Linear regression was calculated between ileal flow and dietary intake of individual AA. The IEIF interpreted as the y-intercept of each linear function responded neither to elevated ingestion of each CF type nor to SO level. Age and DMI had no effect on IEIF computed in relation to BW, but wide discrepancies resulted when related to DMI. Overall IEIF of AA varied between 14.3 to 129.8 mg/kg BW d-1. These flows were established in model computations to account for 10 to 64% of the recommended intake of limiting AA. In conclusion the ileal inevitable flow is constant within the dietary/age conditions investigated. However it is modulated by feed intake and accounts for a significant portion of total amino acid requirement. © 2017 Poultry Science Association Inc.

  12. Accumulation of N and P in the Legume Lespedeza davurica in Controlled Mixtures with the Grass Bothriochloa ischaemum under Varying Water and Fertilization Conditions.

    Science.gov (United States)

    Xu, Bingcheng; Xu, Weizhou; Wang, Zhi; Chen, Zhifei; Palta, Jairo A; Chen, Yinglong

    2018-01-01

    Water and fertilizers affect the nitrogen (N) and phosphorus (P) acquisition and allocation among organs in dominant species in natural vegetation on the semiarid Loess Plateau. This study aimed to clarify the N and P accumulation and N:P ratio at organ and plant level of a local legume species mixed with a grass species under varying water and fertilizer supplies, and thus to fully understand the requirements and balance of nutrient elements in response to growth conditions change of native species. The N and P concentration in the organ (leaf, stem, and root) and plant level of Lespedeza davurica (C 3 legume), were examined when intercropped with Bothriochloa ischaemum (C 4 grass). The two species were grown outdoors in pots under 80, 60, and 40% of soil water field capacity (FC), -NP, +N, +P, and +NP supply and the grass:legume mixture ratios of 2:10, 4:8, 6:6, 8:4, 10:2, and 12:0. The three set of treatments were under a randomized complete block design. Intercropping with B. ischaemum did not affect N concentrations in leaf, stem and root of L. davurica , but reduced P concentration in each organ under P fertilization. Only leaf N concentration in L. davurica showed decreasing trend as soil water content decreased under all fertilization and mixture proportion treatments. Stems had the lowest, while roots had the highest N and P concentration. As the mixture proportion of L. davurica decreased under P fertilization, P concentration in leaf and root also decreased. The N concentration in L. davurica at the whole plant level was 11.1-17.2%. P fertilization improved P concentration, while decreased N:P ratio in L. davurica . The N:P ratios were less than 14.0 under +P and +NP treatments. Our results implied that exogenous N and P fertilizer application may change the N:P stoichiometry and influence the balance between nutrients and organs of native dominant species in natural grassland, and P element should be paid more attention when considering rehabilitating

  13. Accumulation of N and P in the Legume Lespedeza davurica in Controlled Mixtures with the Grass Bothriochloa ischaemum under Varying Water and Fertilization Conditions

    Directory of Open Access Journals (Sweden)

    Bingcheng Xu

    2018-02-01

    Full Text Available Water and fertilizers affect the nitrogen (N and phosphorus (P acquisition and allocation among organs in dominant species in natural vegetation on the semiarid Loess Plateau. This study aimed to clarify the N and P accumulation and N:P ratio at organ and plant level of a local legume species mixed with a grass species under varying water and fertilizer supplies, and thus to fully understand the requirements and balance of nutrient elements in response to growth conditions change of native species. The N and P concentration in the organ (leaf, stem, and root and plant level of Lespedeza davurica (C3 legume, were examined when intercropped with Bothriochloa ischaemum (C4 grass. The two species were grown outdoors in pots under 80, 60, and 40% of soil water field capacity (FC, -NP, +N, +P, and +NP supply and the grass:legume mixture ratios of 2:10, 4:8, 6:6, 8:4, 10:2, and 12:0. The three set of treatments were under a randomized complete block design. Intercropping with B. ischaemum did not affect N concentrations in leaf, stem and root of L. davurica, but reduced P concentration in each organ under P fertilization. Only leaf N concentration in L. davurica showed decreasing trend as soil water content decreased under all fertilization and mixture proportion treatments. Stems had the lowest, while roots had the highest N and P concentration. As the mixture proportion of L. davurica decreased under P fertilization, P concentration in leaf and root also decreased. The N concentration in L. davurica at the whole plant level was 11.1–17.2%. P fertilization improved P concentration, while decreased N:P ratio in L. davurica. The N:P ratios were less than 14.0 under +P and +NP treatments. Our results implied that exogenous N and P fertilizer application may change the N:P stoichiometry and influence the balance between nutrients and organs of native dominant species in natural grassland, and P element should be paid more attention when considering

  14. Regional scenario building as a tool to support vulnerability assessment of food & water security and livelihood conditions under varying natural resources managements

    Science.gov (United States)

    Reinhardt, Julia; Liersch, Stefan; Dickens, Chris; Kabaseke, Clovis; Mulugeta Lemenih, Kassaye; Sghaier, Mongi; Hattermann, Fred

    2013-04-01

    Participatory regional scenario building was carried out with stakeholders and local researchers in four meso-scale case studies (CS) in Africa. In all CS the improvement of food and / or water security and livelihood conditions was identified as the focal issue. A major concern was to analyze the impacts of different plausible future developments on these issues. The process of scenario development is of special importance as it helps to identify main drivers, critical uncertainties and patterns of change. Opportunities and constraints of actors and actions become clearer and reveal adaptation capacities. Effective strategies must be furthermore reasonable and accepted by local stakeholders to be implemented. Hence, developing scenarios and generating strategies need the integration of local knowledge. The testing of strategies shows how they play out in different scenarios and how robust they are. Reasons and patterns of social and natural vulnerability can so be shown. The scenario building exercise applied in this study is inspired by the approach from Peter Schwartz. It aims at determining critical uncertainties and to identify the most important driving forces for a specific focal issue which are likely to shape future developments of a region. The most important and uncertain drivers were analyzed and systematized with ranking exercises during meetings with local researchers and stakeholders. Cause-effect relationships were drawn in the form of concept maps either during the meetings or by researchers based on available information. Past observations and the scenario building outcomes were used to conduct a trend analysis. Cross-comparisons were made to find similarities and differences between CS in terms of main driving forces, patterns of change, opportunities and constraints. Driving forces and trends which aroused consistently over scenarios and CS were identified. First results indicate that livelihood conditions of people rely often directly on the

  15. Determination of dissolution rates of spent fuel in carbonate solutions under different redox conditions with a flow-through experiment

    International Nuclear Information System (INIS)

    Roellin, S.; Spahiu, K.; Eklund, U.-B.

    2001-01-01

    Dissolution rates of spent UO 2 fuel have been investigated using flow-through experiments under oxidizing, anoxic and reducing conditions. For oxidizing conditions, approximately congruent dissolution rates were obtained in the pH range 3-9.3 for U, Np, Ba, Tc, Cs, Sr and Rb. For these elements, steady-state conditions were obtained in the flow rate range 0.02-0.3 ml min -1 . The dissolution rates were about 3 mg d -1 m -2 for pH>6. For pH 2 (g) saturated solutions dropped by up to four orders of magnitude as compared to oxidizing conditions. Because of the very low concentrations, only U, Pu, Am, Mo, Tc and Cs could be measured. For anoxic conditions, both the redox potential and dissolution rates increased approaching the same values as under oxidizing conditions

  16. Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions

    International Nuclear Information System (INIS)

    Turner, J.P.; Hasfurther, V.

    1992-01-01

    The scope of the research program and the continuation is to study interacting hydrologic, geotechnical, and chemical factors affecting the behavior and disposal of combusted processed oil shale. The research combines bench-scale testing with large scale research sufficient to describe commercial scale embankment behavior. The large scale approach was accomplished by establishing five lysimeters, each 7.3 x 3.0 x 3.0 m deep, filled with processed oil shale that has been retorted and combusted by the Lurgi-Ruhrgas (Lurgi) process. Approximately 400 tons of Lurgi processed oil shale waste was provided by Rio Blanco Oil Shale Co., Inc. (RBOSC) through a separate cooperative agreement with the University of Wyoming (UW) to carry out this study. Three of the lysimeters were established at the RBOSC Tract C-a in the Piceance Basin of Colorado. Two lysimeters were established in the Environmental Simulation Laboratory (ESL) at UW. The ESL was specifically designed and constructed so that a large range of climatic conditions could be physically applied to the processed oil shale which was filled in the lysimeter cells

  17. Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions

    International Nuclear Information System (INIS)

    Turner, J.P.; Reeves, T.L.; Skinner, Q.D.; Hasfurther, V.

    1992-11-01

    The scope of the original research program and of its continuation is to study interacting hydrologic, geotechnical, and chemical factors affecting the behavior and disposal of combusted processed oil shale. The research combines bench-scale testing with large-scale testing sufficient to describe commercial-scale embankment behavior. The large-scale testing was accomplished by constructing five lysimeters, each 7.3x3.0x3.0 m deep, filled with processed oil shale that has been retorted and combusted by the Lurgi-Ruhrgas (Lurgi) process (Schmalfield 1975). Approximately 400 tons of Lurgi processed oil shale waste was provided by Rio Blanco Oil Shale Co., Inc. to carry out this study. Three of the lysimeters were established at the RBOSC Tract C-a in the Piceance Basin near Rifle, Colorado. Two lysimeters were established in the Environmental Simulation Laboratory (ESL) at UW. The ESL was specifically designed and constructed so that a large range of climatic conditions could be physically applied to the processed oil shale which was placed in the lysimeter cells. This report discusses and summarizes results from scientific efforts conducted between October 1991 and September 1992 for Fiscal Year 1992

  18. Modeling solute transport in a heterogeneous unsaturated porous medium under dynamic boundary conditions on different spatial scales

    Science.gov (United States)

    Cremer, Clemens; Neuweiler, Insa; Bechtold, Michel

    2013-04-01

    Understanding transport of solutes/contaminants through unsaturated soil in the shallow subsurface is vital to assess groundwater quality, nutrient cycling or to plan remediation projects. Alternating precipitation and evaporation conditions causing upward and downward flux with differing flow paths, changes in saturation and related structural heterogeneity make the description of transport in the unsaturated zone near the soil-surface a complex problem. Preferential flow paths strongly depend, among other things, on the saturation of a medium. Recent studies (e.g. Bechtold et al., 2011) showed lateral flow and solute transport during evaporation conditions (upward flux) in vertically layered sand columns. Results revealed that during evaporation water and solute are redistributed laterally from coarse to fine media deeper in the soil, and towards zones of lowest hydraulic head near to the soil surface. These zones at the surface can be coarse or fine grained depending on saturation status and evaporation flux. However, if boundary conditions are reversed and precipitation is applied, the flow field is not 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 in the shallow unsaturated zone. In this contribution, we analyze transport of a solute in the shallow subsurface to assess effects resulting from the superposition of heterogeneous soil structures and dynamic flow conditions on various spatial scales. Two-dimensional numerical simulations of unsaturated flow and transport in heterogeneous porous media under changing boundary conditions are carried out using a finite-volume code coupled to a particle tracking algorithm to quantify solute transport and leaching rates. In order to validate numerical simulations, results are qualitatively compared to those of a physical experiment (Bechtold et al., 2011). Numerical

  19. FORSIM, Solution of Ordinary or Partial Differential Equation with Initial Conditions

    International Nuclear Information System (INIS)

    Carver, M.B.

    1985-01-01

    1 - Description of problem or function: FORSIM is a FORTRAN oriented simulation program which automates the continuous transient solution of systems of ordinary and/or partial differential equations. The user writes his equations in a FORTRAN subroutine, following prescribed rules, and loads this routine along with the executive routines. The executive routines then read in initial data supplied by the user and proceed with the integration. 2 - Method of solution: Partial differential equations are converted to coupled ordinary differential equations by suitable discretization formulae. Integration is done by variable order, variable step-size error controlled algorithms. 3 - Restrictions on the complexity of the problem - Maximum of: 1000 ordinary differential equations

  20. Macro and micro observations on mortar alternation mechanism under the various solution conditions

    International Nuclear Information System (INIS)

    Fujiwara, A.; Tashiro, S.; Takemura, T.; Sakogaichi, K.; Yokomoto, S.; Katsuyama, K.

    1995-01-01

    Accelerated aging tests have been conducted to evaluate the long-term durability of cementitious material against aggressive ions. In tests, cementitious specimens were immersed in the solutions containing concentrated aggressive ions at high temperature and it promoted diffusion of the ions in the specimen. This method would be suitable for the evaluation on the aging as the alteration of the specimen would be expected to resemble the natural behavior. This paper presents a classification of alteration mechanism in the immersion tests using MgCl 2 and Na 2 SO 4 solution. This classification was done by relating the changes of compressive strength to microscopic and mineralogical changes

  1. Approximate analytical solution to diurnal atmospheric boundary-layer growth under well-watered conditions

    Science.gov (United States)

    The system of governing equations of a simplified slab model of the uniformly-mixed, purely convective, diurnal atmospheric boundary layer (ABL) is shown to allow immediate solutions for the potential temperature and specific humidity as functions of the ABL height and net radiation when expressed i...

  2. Mild solutions to a measure-valued mass evolution problem with flux boundary conditions

    NARCIS (Netherlands)

    Evers, J.H.M.; Hille, S.C.; Muntean, A.

    2015-01-01

    We investigate the well-posedness and approximation of mild solutions to a class of linear transport equations on the unit interval [0,1][0,1] endowed with a linear discontinuous production term, formulated in the space M([0,1])M([0,1]) of finite Borel measures. Our working technique includes a

  3. Boundary conditions for the numerical solution of elliptic equations in exterior regions

    International Nuclear Information System (INIS)

    Bayliss, A.; Gunzburger, M.; Turkel, E.

    1982-01-01

    Elliptic equations in exterior regions frequently require a boundary condition at infinity to ensure the well-posedness of the problem. Examples of practical applications include the Helmholtz equation and Laplace's equation. Computational procedures based on a direct discretization of the elliptic problem require the replacement of the condition at infinity by a boundary condition on a finite artificial surface. Direct imposition of the condition at infinity along the finite boundary results in large errors. A sequence of boundary conditions is developed which provides increasingly accurate approximations to the problem in the infinite domain. Estimates of the error due to the finite boundary are obtained for several cases. Computations are presented which demonstrate the increased accuracy that can be obtained by the use of the higher order boundary conditions. The examples are based on a finite element formulation but finite difference methods can also be used

  4. Effects of Solution-Based Fabrication Conditions on Morphology of Lead Halide Perovskite Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Jeremy L. Barnett

    2016-01-01

    Full Text Available We present a critical review of the effects of processing conditions on the morphology of methylammonium lead iodide (CH3NH3PbI3 perovskite solar cells. Though difficult to decouple from synthetic and film formation effects, a single morphological feature, specifically grain size, has been evidently linked to the photovoltaic performance of this class of solar cells. Herein, we discuss experimental aspects of optimizing the (a temperature and time of annealing, (b spin-coating parameters, and (c solution temperature of methylammonium iodide (MAI solution.

  5. Necessary and Sufficient Conditions for the Existence of Positive Solution for Singular Boundary Value Problems on Time Scales

    Directory of Open Access Journals (Sweden)

    Meiqiang Feng

    2009-01-01

    Full Text Available By constructing available upper and lower solutions and combining the Schauder's fixed point theorem with maximum principle, this paper establishes sufficient and necessary conditions to guarantee the existence of Cld[0,1]𝕋 as well as CldΔ[0,1]𝕋 positive solutions for a class of singular boundary value problems on time scales. The results significantly extend and improve many known results for both the continuous case and more general time scales. We illustrate our results by one example.

  6. Effects of solution pH and complexing reagents on uranium and thorium desorption under saturated equilibrium conditions

    International Nuclear Information System (INIS)

    Wang, Yug-Yea; Yu, C.

    1992-01-01

    Three contaminated bulk surface soils were used for investigating the effect of solution pH and complexing reagents on uranium and thorium desorption. At a low solution pH, the major chemical species of uranium and thorium, uranyl UO 2 +2 , thorium dihydroxide Th(OH) 2 +2 , and thorium hydroxide Th(OH) +3 , tend to form complexes with acetates in the solution phase, which increases the fractions of uranium and thorium desorbed into this phase. At a high solution pH, important uranium and thorium species such as uranyl tricarbonate complex UO 2 (CO) 33 -4 and thorium tetrahydroxide complex Th(OH) 4 tend to resist complexation with acetates. The presence of complexing reagents in solution can release radionuclides such as uranium and/or thorium from the soil to the solution by forming soluble complexes. Sodium bicarbonate (NaHCO 3 ) and diethylenetriaminepentaacetic acid (DTPA) are strong complex formers that released 38% to 62% of total uranium activity and 78% to 86% of total thorium activity, respectively, from the soil samples investigated. Solutions of 0.1 molar sodium nitrate (NaNO 3 ) and 0.1 molar sodium sulfate (Na 2 SO 4 ) were not effective complex formers with uranium and thorium under the experimental conditions. Fractions of uranium and thorium desorbed by 0.15g/200ml humic acid ranged from 4.62% to 6.17% and 1.59% to 7.09%, respectively. This work demonstrates the importance of a knowledge of solution chemistry in investigating the desorption of radionuclides

  7. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    International Nuclear Information System (INIS)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi

    2015-01-01

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity

  8. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    Energy Technology Data Exchange (ETDEWEB)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi [Universiti Teknologi Malaysia, Skudai (Malaysia)

    2015-04-15

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity.

  9. High-Order Finite-Difference Solution of the Poisson Equation with Interface Jump Conditions II

    Science.gov (United States)

    Marques, Alexandre; Nave, Jean-Christophe; Rosales, Rodolfo

    2010-11-01

    The Poisson equation with jump discontinuities across an interface is of central importance in Computational Fluid Dynamics. In prior work, Marques, Nave, and Rosales have introduced a method to obtain fourth-order accurate solutions for the constant coefficient Poisson problem. Here we present an extension of this method to solve the variable coefficient Poisson problem to fourth-order of accuracy. The extended method is based on local smooth extrapolations of the solution field across the interface. The extrapolation procedure uses a combination of cubic Hermite interpolants and a high-order representation of the interface using the Gradient-Augmented Level-Set technique. This procedure is compatible with the use of standard discretizations for the Laplace operator, and leads to modified linear systems which have the same sparsity pattern as the standard discretizations. As a result, standard Poisson solvers can be used with only minimal modifications. Details of the method and applications will be presented.

  10. On exact solutions for oscillatory flows in a generalized Burgers fluid with slip condition

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Tasawar [Dept. of Mathematics, Quaid-i-Azam Univ., Islamabad (Pakistan); Dept. of Mathematics, Coll. of Sciences, KS Univ., Riyadh (Saudi Arabia); Najam, Saher [Theoretical Plasma Physics Div., PINSTECH, P.O. Nilore, Islamabad (Pakistan); Sajid, Muhammad; Mesloub, Said [Dept. of Mathematics, Coll. of Sciences, KS Univ., Riyadh (Saudi Arabia); Ayub, Muhammad [Dept. of Mathematics, Quaid-i-Azam Univ., Islamabad (Pakistan)

    2010-05-15

    An analysis is performed for the slip effects on the exact solutions of flows in a generalized Burgers fluid. The flow modelling is based upon the magnetohydrodynamic (MHD) nature of the fluid and modified Darcy law in a porous space. Two illustrative examples of oscillatory flows are considered. The results obtained are compared with several limiting cases. It has been shown here that the derived results hold for all values of frequencies including the resonant frequency. (orig.)

  11. Analytical solutions for tomato peeling with combined heat flux and convective boundary conditions

    Science.gov (United States)

    Cuccurullo, G.; Giordano, L.; Metallo, A.

    2017-11-01

    Peeling of tomatoes by radiative heating is a valid alternative to steam or lye, which are expensive and pollutant methods. Suitable energy densities are required in order to realize short time operations, thus involving only a thin layer under the tomato surface. This paper aims to predict the temperature field in rotating tomatoes exposed to the source irradiation. Therefore, a 1D unsteady analytical model is presented, which involves a semi-infinite slab subjected to time dependent heating while convective heat transfer takes place on the exposed surface. In order to account for the tomato rotation, the heat source is described as the positive half-wave of a sinusoidal function. The problem being linear, the solution is derived following the Laplace Transform Method. In addition, an easy-to-handle solution for the problem at hand is presented, which assumes a differentiable function for approximating the source while neglecting convective cooling, the latter contribution turning out to be negligible for the context at hand. A satisfying agreement between the two analytical solutions is found, therefore, an easy procedure for a proper design of the dry heating system can be set up avoiding the use of numerical simulations.

  12. Transport of titanium dioxide nanoparticles in saturated porous media under various solution chemistry conditions

    International Nuclear Information System (INIS)

    Wang Yu; Gao Bin; Morales, Verónica L.; Tian Yuan; Wu Lei; Gao Jie; Bai Wei; Yang Liuyan

    2012-01-01

    Because of its wide applications, nanosized titanium dioxide may become a potential environmental risk to soil and groundwater system. It is therefore important to improve current understanding of the environmental fate and transport of titanium oxides nanoparticles (TONPs). In this work, the effect of solution chemistry (i.e., pH, ionic strength, and natural organic matter (NOM) concentration) on the deposition and transport of TONPs in saturated porous media was examined in detail. Laboratory columns packed with acid-cleaned quartz sand were used in the experiment as porous media. Transport experiments were conducted with various chemistry combinations, including four ionic strengths, three pH levels, and two NOM concentrations. The results showed that TONP mobility increased with increasing solution pH, but decreased with increasing solution ionic strength. It is also found that the presence of NOM in the system enhanced the mobility of TONPs in the saturated porous media. The Derjaguin–Landau–Verwey–Overbeek (DLVO) theory was used to justify the mobility trends observed in the experimental data. Predictions from the theory agreed excellently with the experimental data.

  13. A fast Cauchy-Riemann solver. [differential equation solution for boundary conditions by finite difference approximation

    Science.gov (United States)

    Ghil, M.; Balgovind, R.

    1979-01-01

    The inhomogeneous Cauchy-Riemann equations in a rectangle are discretized by a finite difference approximation. Several different boundary conditions are treated explicitly, leading to algorithms which have overall second-order accuracy. All boundary conditions with either u or v prescribed along a side of the rectangle can be treated by similar methods. The algorithms presented here have nearly minimal time and storage requirements and seem suitable for development into a general-purpose direct Cauchy-Riemann solver for arbitrary boundary conditions.

  14. Solution of a Problem Linear Plane Elasticity with Mixed Boundary Conditions by the Method of Boundary Integrals

    Directory of Open Access Journals (Sweden)

    Nahed S. Hussein

    2014-01-01

    Full Text Available A numerical boundary integral scheme is proposed for the solution to the system of …eld equations of plane. The stresses are prescribed on one-half of the circle, while the displacements are given. The considered problem with mixed boundary conditions in the circle is replaced by two problems with homogeneous boundary conditions, one of each type, having a common solution. The equations are reduced to a system of boundary integral equations, which is then discretized in the usual way, and the problem at this stage is reduced to the solution to a rectangular linear system of algebraic equations. The unknowns in this system of equations are the boundary values of four harmonic functions which define the full elastic solution and the unknown boundary values of stresses or displacements on proper parts of the boundary. On the basis of the obtained results, it is inferred that a stress component has a singularity at each of the two separation points, thought to be of logarithmic type. The results are discussed and boundary plots are given. We have also calculated the unknown functions in the bulk directly from the given boundary conditions using the boundary collocation method. The obtained results in the bulk are discussed and three-dimensional plots are given. A tentative form for the singular solution is proposed and the corresponding singular stresses and displacements are plotted in the bulk. The form of the singular tangential stress is seen to be compatible with the boundary values obtained earlier. The efficiency of the used numerical schemes is discussed.

  15. Quasilocal energy for three-dimensional massive gravity solutions with chiral deformations of AdS{sub 3} boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Garbarz, Alan, E-mail: alan-at@df.uba.ar [Departamento de Física, Universidad de Buenos Aires FCEN-UBA, IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires, Argentina and Instituto de Física de La Plata, Universidad Nacional de La Plata IFLP-UNLP, C.C. 67 (Argentina); Giribet, Gaston, E-mail: gaston-at@df.uba.ar, E-mail: af.goya-at@df.uba.ar; Goya, Andrés, E-mail: gaston-at@df.uba.ar, E-mail: af.goya-at@df.uba.ar [Departamento de Física, Universidad de Buenos Aires FCEN-UBA, IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Leston, Mauricio, E-mail: mauricio-at@iafe.uba.ar [Instituto de Astronomía y Física del Espacio IAFE-CONICET, Ciudad Universitaria, C.C. 67 Suc. 28, 1428, Buenos Aires (Argentina)

    2015-03-26

    We consider critical gravity in three dimensions; that is, the New Massive Gravity theory formulated about Anti-de Sitter (AdS) space with the specific value of the graviton mass for which it results dual to a two-dimensional conformai field theory with vanishing central charge. As it happens with Kerr black holes in four-dimensional critical gravity, in three-dimensional critical gravity the Bañados-Teitelboim-Zanelli black holes have vanishing mass and vanishing angular momentum. However, provided suitable asymptotic conditions are chosen, the theory may also admit solutions carrying non-vanishing charges. Here, we give simple examples of exact solutions that exhibit falling-off conditions that are even weaker than those of the so-called Log-gravity. For such solutions, we define the quasilocal stress-tensor and use it to compute conserved charges. Despite the drastic deformation of AdS{sub 3} asymptotic, these solutions have finite mass and angular momentum, which are shown to be non-zero.

  16. THE PREDICTION OF pH BY GIBBS FREE ENERGY MINIMIZATION IN THE SUMP SOLUTION UNDER LOCA CONDITION OF PWR

    Directory of Open Access Journals (Sweden)

    HYOUNGJU YOON

    2013-02-01

    Full Text Available It is required that the pH of the sump solution should be above 7.0 to retain iodine in a liquid phase and be within the material compatibility constraints under LOCA condition of PWR. The pH of the sump solution can be determined by conventional chemical equilibrium constants or by the minimization of Gibbs free energy. The latter method developed as a computer code called SOLGASMIX-PV is more convenient than the former since various chemical components can be easily treated under LOCA conditions. In this study, SOLGASMIX-PV code was modified to accommodate the acidic and basic materials produced by radiolysis reactions and to calculate the pH of the sump solution. When the computed pH was compared with measured by the ORNL experiment to verify the reliability of the modified code, the error between two values was within 0.3 pH. Finally, two cases of calculation were performed for the SKN 3&4 and UCN 1&2. As results, pH of the sump solution for the SKN 3&4 was between 7.02 and 7.45, and for the UCN 1&2 plant between 8.07 and 9.41. Furthermore, it was found that the radiolysis reactions have insignificant effects on pH because the relative concentrations of HCl, HNO3, and Cs are very low.

  17. Straw incorporation increases crop yield and soil organic carbon sequestration but varies under different natural conditions and farming practices in China: a system analysis

    OpenAIRE

    Han, Xiao; Xu, Cong; Dungait, Jennifer A. J.; Bol, Roland; Wang, Xiaojie; Wu, Wenliang; Meng, Fanqiao

    2018-01-01

    Loss of soil organic carbon (SOC) from agricultural soils is a key indicator of soil degradation associated with reductions in net primary productivity in crop production systems worldwide. Technically simple and locally appropriate solutions are required for farmers to increase SOC and to improve cropland management. In the last 30 years, straw incorporation (SI) has gradually been implemented across China in the context of agricultural intensification and rural liveliho...

  18. Modelling LiBr-H2O solution concentration/crystallization of low thermal-powered absorption air conditioning system

    International Nuclear Information System (INIS)

    Abdullah, M.O.

    2000-01-01

    A computer model is developed to predict the concentration of lithium bromide - water (LiBr-H 2 O) solution for used in low thermal energy-driven absorption air conditioning plants design. The computer program is capable to alert the users from undesirable solidification or crystallization zones. Good agreements between simulated concentration and experimental data from standard chart/table have been obtained. (Author)

  19. Microstructure, mechanical property and metal release of As-SLM CoCrW alloy under different solution treatment conditions.

    Science.gov (United States)

    Lu, Yanjin; Wu, Songquan; Gan, Yiliang; Zhang, Shuyuan; Guo, Sai; Lin, Junjie; Lin, Jinxin

    2015-03-01

    In the study, the microstructure, mechanical property and metal release behavior of selective laser melted CoCrW alloys under different solution treatment conditions were systemically investigated to assess their potential use in orthopedic implants. The effects of the solution treatment on the microstructure, mechanical properties and metal release were systematically studied by OM, SEM, XRD, tensile test, and ICP-AES, respectively. The XRD indicated that during the solution treatment the alloy underwent the transformation of γ-fcc to ε-hcp phase; the ε-hcp phase nearly dominated in the alloy when treated at 1200°C following the water quenching; the results from OM, SEM showed that the microstructural change was occurred under different solution treatments; solution at 1150°C with furnace cooling contributed to the formation of larger precipitates at the grain boundary regions, while the size and number of the precipitates was decreased as heated above 1100°C with the water quenching; moreover, the diamond-like structure was invisible at higher solution temperature over 1150°C following water quenching; compared with the furnace cooling, the alloy quenched by water showed excellent mechanical properties and low amount of metal release; as the alloy heated at 1200°C, the mechanical properties of the alloy reached their optimum combination at UTS=1113.6MPa, 0.2%YS=639.5MPa, and E%=20.1%, whilst showed the lower total quantity of metal release. It is suggested that a proper solution treatment is an efficient strategy for improving the mechanical properties and corrosion resistance of As-SLM CoCrW alloy that show acceptable tensile ductility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Optimisation of liquid scintillation counting conditions to determine low activity levels of tritium and radiostrontium in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Rauret, Gemma; Mestres, J.S.; Ribera, Merce; Rajadel, Pilar (Barcelona Univ. (Spain). Dept. de Quimica Analitica)

    1990-08-01

    An optimisation of the counting conditions for the measurement of aqueous solutions of tritium or radiostrontium using Insta-Gel II as scintillator is presented. The variables optimised were the window, the ratio of mass of sample to mass of scintillator and the total volume of the counting mixture. An optimisation function which takes into account each of these variables, the background and also the efficiency is proposed. The conditions established allow the lowest possible detection limit to be reached. For tritium, this value was compared with that obtained when the standard method for water analysis was applied. (author).

  1. Solution structure of detergent micelles at conditions relevant to membrane protein crystallization.

    Energy Technology Data Exchange (ETDEWEB)

    Littrell, K.; Thiyagarajan, P.; Tiede, D.; Urban, V.

    1999-07-02

    In this study small angle neutron scattering was used to characterize the formation of micelles in aqueous solutions of the detergents DMG and SPC as a function of detergent concentration and ionic strength of the solvent. The effects on the micelle structure of the additives glycerol and PEG, alone as well as in combination typical for actual membrane protein crystallization, were also explored. This research suggests that the micelles are cigar-like in form at the concentrations studied. The size of the micelles was observed to increase with increasing ionic strength but decrease with the addition of glycerol or PEG.

  2. Ground State Solutions for a Class of Fractional Differential Equations with Dirichlet Boundary Value Condition

    Directory of Open Access Journals (Sweden)

    Zhigang Hu

    2014-01-01

    Full Text Available In this paper, we apply the method of the Nehari manifold to study the fractional differential equation (d/dt((1/2 0Dt-β(u′(t+(1/2 tDT-β(u′(t=  f(t,u(t, a.e. t∈[0,T], and u0=uT=0, where  0Dt-β, tDT-β are the left and right Riemann-Liouville fractional integrals of order 0≤β<1, respectively. We prove the existence of a ground state solution of the boundary value problem.

  3. Existence and multiplicity of solutions to elliptic problems with discontinuities and free boundary conditions

    Directory of Open Access Journals (Sweden)

    Sabri Bensid

    2010-04-01

    Full Text Available We study the nonlinear elliptic problem with discontinuous nonlinearity $$displaylines{ -Delta u = f(uH(u-mu quadhbox{in } Omega, cr u =h quad hbox{on }partial Omega, }$$ where $H$ is the Heaviside unit function, $f,h$ are given functions and $mu$ is a positive real parameter. The domain $Omega$ is the unit ball in $mathbb{R}^n$ with $ngeq 3$. We show the existence of a positive solution $u$ and a hypersurface separating the region where $-Delta u=0$ from the region where $-Delta u=f(u$. Our method relies on the implicit function theorem and bifurcation analysis.

  4. Covariant interactions of two spinless particles: all local solutions of the angular condition

    International Nuclear Information System (INIS)

    Leutwyler, H.; Stern, J.

    1977-06-01

    The solutions of the algebraic problem posed by covariant Hamiltonian quantum mechanics are discussed. If, in the transverse relative coordinates, the mass and spin operators are differential operators of at most second order, the system is shown to be described by a manifestly covariant wave equation supplemented with a covariant constraint. If, in addition, one requires the wave equation and the constraint to be local in the coordinates of both particles, the freedom left in the interaction reduces to four constants. The resulting class of systems represents a generalization of the relativistic oscillator of Feynman, Kislinger and Ravndal

  5. Divergent series and memory of the initial condition in the long-time solution of some anomalous diffusion problems.

    Science.gov (United States)

    Yuste, S Bravo; Borrego, R; Abad, E

    2010-02-01

    We consider various anomalous d -dimensional diffusion problems in the presence of an absorbing boundary with radial symmetry. The motion of particles is described by a fractional diffusion equation. Their mean-square displacement is given by r(2) proportional, variant t(gamma)(0divergent series appear when the concentration or survival probabilities are evaluated via the method of separation of variables. While the solution for normal diffusion problems is, at most, divergent as t-->0 , the emergence of such series in the long-time domain is a specific feature of subdiffusion problems. We present a method to regularize such series, and, in some cases, validate the procedure by using alternative techniques (Laplace transform method and numerical simulations). In the normal diffusion case, we find that the signature of the initial condition on the approach to the steady state rapidly fades away and the solution approaches a single (the main) decay mode in the long-time regime. In remarkable contrast, long-time memory of the initial condition is present in the subdiffusive case as the spatial part Psi1(r) describing the long-time decay of the solution to the steady state is determined by a weighted superposition of all spatial modes characteristic of the normal diffusion problem, the weight being dependent on the initial condition. Interestingly, Psi1(r) turns out to be independent of the anomalous diffusion exponent gamma .

  6. Treatment and Conditioning of Radioactive Waste Solution by Natural Clay Minerals

    International Nuclear Information System (INIS)

    El-Dessouky, M.I.; Abdel-Raouf, M.W.; El-Massry, E.H.; Khalifa, S.M.; Aly, H.F.

    1999-01-01

    Chemical precipitation processes have been used for the treatment of radioactive elements from aqueous solution. The volume reduction is not very great and storage facilities are expensive. There are some radionuclides which are so difficult to be precipitated by this common method, so they may be precipitated by adding solid materials such as natural inorganic exchangers. In this woek, improvement the removal of caesium, cobalt and europium with zinc sulfate as coagulant and different clay minerals have been investigated. These include, Feldespare, Aswanly, Bentionite, Hematite, Mud, Calcite, Basalt, Magnetite, Kaoline, Sand stone, Limonite and Sand. The parameters affecting the precipitation process such as pH, particle size, temperature and weight of the clay have been studied. The results indicate that, the highest removal for Cs-137, Co-60 and Eu-152 and154 by Asswanly, Bentonite and Sand stone is more than the other clays. Removal of Cs-137 from low level waste solution with these three natural clays took the sequence, Aswanly (85.5%) > Bentonite (82.2%) > Sandstone (65.4%). Solidified cement products have been evaluated to determine mechanical strength and leaching rates of the waste products. The solidified waste forms were found more acceptable for handling ,storage and ultimate disposal

  7. Equilibrium and kinetic models for colloid release under transient solution chemistry conditions

    Science.gov (United States)

    We present continuum models to describe colloid release in the subsurface during transient physicochemical conditions. Our modeling approach relates the amount of colloid release to changes in the fraction of the solid surface area that contributes to retention. Equilibrium, kinetic, equilibrium and...

  8. Conditioning highly concentrated borate solutions with calcium sulfo-aluminate cement

    International Nuclear Information System (INIS)

    Champenois, J.B.; Cau dit Coumes, C.; Poulesquen, A.; Le Bescop, P.; Damidot, D.

    2012-01-01

    The early age hydration by borate solution of 3 calcium sulfo-aluminate cements (CSA), containing respectively 0%, 10% and 20% of gypsum by weight of cement was studied using isothermal calorimetry and dynamic mode rheo-metry. XRD and TGA analysis were carried out on pastes with increasing hydration degrees (up to 90 days) to specify the mineralogy and to figure out the mechanisms of borate immobilisation. It has been shown that the retarding effect of borate anions is due to the precipitation of the amorphous calcium borate C 2 B 3 H 8 ; borate anions were then incorporated in Aft-type phases. The macroscopic properties of hydrated binders (compressive strength, length change) were also followed during 180 days. It appears that the mechanical strength continuously increases with the hydration degree. Length changes under wet-curing and sealed bag remain moderate and seem to be stabilized after 180 days

  9. Citrate-coated silver nanoparticles interactions with effluent organic matter: influence of capping agent and solution conditions

    KAUST Repository

    Gutierrez, Leonardo

    2015-07-31

    of solution conditions and capping agents on the stability of AgNPs in solution. However, the characteristics of organics would play a crucial role in the fate and transport of these nano contaminants in urban wastewaters and natural water systems.

  10. Conditions of Antonin seam exploitation in the open pit Druzba near Sokolov with regard to the protection of thermal and mineral water resources in Karlovy Vary

    International Nuclear Information System (INIS)

    Grmela, A.; Sterba, J.

    1997-01-01

    From new structural-tectonic findings concerning the extent and character of the Nove Sedlo fault in the area of the Druzba open pit in the Sokolov Basin, it is evident that it is a form of listric fault of shallow range, ending in an intermediate slip. This finding has a decisive relevance for deciding as to the current placement of the pit in the protection zone of Karlovy Vary's thermal springs. For the purposes of the exploitation of the Antonin seam, it is necessary to create a network of multipurpose bore holes at the bottom of the pit and in front of the working face for the regulation of pressure in the basal aquifer and to ensure unity of monitoring and its complex evaluation on the basis of numerical modelling of the hydrodynamic state of the basal aquifer and the geotechnical processes of the seam's impermeable bedrock. 4 refs

  11. CIRCUIT-DESIGN SOLUTIONS AND INFORMATION SUPPORT OF CITY ELECTRIC NETWORKS IN THE CONDITIONS OF THE SMART GRID

    Directory of Open Access Journals (Sweden)

    M. I. Fursanov

    2017-01-01

    Full Text Available The structure, circuit-design solutions and information support of the city electric networks in the conditions of the SMART GRID have been analyzed. It is demonstrated that the new conditions of functioning of electric power engineering, increasing demands for its technological state and reliability in most countries determined the transition to a restructuring of electrical networks to be based on the SMART GRID (intelligent power networks innovative new structure. The definitions of the SMART GRID, its various attributes and characteristics in most developed countries including Belarus are presented. It is revealed that the existing and future circuit and constructive solutions that can automate the process of managing modes of urban electric networks under the SMART GRID conditions are manifold. At present, the most common in distribution networks are the sources of distributed generation (combustion turbines, wind turbines, photovoltaic installations, mini-hydro, etc.. The patterns and problems of information traceability of a traditional urban networks of the unified energy system of Belarus have been analyzed, and it is demonstrated that in the conditions of the SMART GRID most of the problems of the control mode that are characteristic for traditional distribution networks 6–10 kV and 0.38 kV, lose their relevance. Therefore, the present article presents and features the main directions of development of automatic control modes of the SMART GRID.

  12. Tracer Studies to Characterize the Effects of Roadside Noise Barriers on Near-Road Pollutant Dispersion under Varying Atmospheric Stability Conditions

    Science.gov (United States)

    A roadway toxics dispersion study was conducted by the Field Research Division (FRD) of NOAA at the Idaho National Laboratory (INL) near Idaho Falls, ID to document the effects on concentrations of roadway emissions behind a roadside sound barrier in various conditions of atmosph...

  13. Validation of an Inter-Cell Interference Coordination Solution in Real-World Deployment Conditions

    DEFF Research Database (Denmark)

    Tonelli, Oscar; Rodriguez, Ignacio; Berardinelli, Gilberto

    2014-01-01

    regular reference scenarios and stochastic channel models are employed. It is an important next step to verify that the trends observed in the reference scenarios compare equally well in more practical deployments. For such comparison, it is required to evaluate an extensive set of link conditions......, reflecting the many possible configurations that can be experienced in a practical scenario. In this paper we adopt an experimental procedure, using a software defined radio testbed, for acquiring almost 1000 different radio link conditions between the nodes of a relevant wireless indoor network scenario....... The acquired measurements, were used in a system level simulator in order to evaluate the performance of a local area decentralized ICIC scheme. The analysis of the algorithm performance results confirms the expected performance trends and allowed to obtain further insights with respect to prior simulation...

  14. A Database for Climatic Conditions around Europe for Promoting GSHP Solutions

    Directory of Open Access Journals (Sweden)

    Michele De Carli

    2018-02-01

    Full Text Available Weather plays an important role for energy uses in buildings. For this reason, it is required to define the proper boundary conditions in terms of the different parameters affecting energy and comfort in buildings. They are also the basis for determining the ground temperature in different locations, as well as for determining the potential for using geothermal energy. This paper presents a database for climates in Europe that has been used in a freeware tool developed as part of the H2020 research project named “Cheap-GSHPs”. The standard Köppen-Geiger climate classification has been matched with the weather data provided by the ENERGYPLUS and METEONORM software database. The Test Reference Years of more than 300 locations have been considered. These locations have been labelled according to the degree-days for heating and cooling, as well as by the Köppen-Geiger scale. A comprehensive data set of weather conditions in Europe has been created and used as input for a GSHP sizing software, helping the user in selecting the weather conditions closest to the location of interest. The proposed method is based on lapse rates and has been tested at two locations in Switzerland and Ireland. It has been demonstrated as quite valid for the project purposes, considering the spatial distribution and density of available data and the lower computing load, in particular for locations where altitude is the main factor controlling on the temperature variations.

  15. Global existence of strong solutions to the three- dimensional incompressible Navier-Stokes equations with special boundary conditions

    Science.gov (United States)

    Riley, Douglas A.

    We study the three-dimensional incompressible Navier- Stokes equations in a domain of the form W'×(0,e) . First, we assume W' is a C3 bounded domain and impose no-slip boundary conditions on 6W'×(0,e ) , and periodic conditions on W'×0,e . Physically, this models fluid flow through a pipe with cross-section W' where the inlet and outlet conditions are assumed periodic. Secondly, we assume W'=(0,l4) ×(0,l5) and impose periodic boundary conditions. This problem is of interest mathematically, and has been more widely considered than the pipe flow problem. For both sets of boundary conditions, we show that a strong solution exists for all time with conditions on the initial data and forcing. We start by recalling that if the forcing function and initial condition do not depend on x3, then a global strong solution exists which also does not depend on x3. Here (x1,x2,x3) ∈W≡W'×( 0,e) . With this observation as motivation, and using an additive decomposition introduced by Raugel and Sell, we split the initial data and forcing into a portion independent of x3 and a remainder. In our first result, we impose a smallness condition on the remainder and assume the forcing function is square- integrable in time as a function into L2(W) . With these assumptions, we prove a global existence theorem that does not require a smallness condition on e or on the portion of the initial condition and forcing independent of x3. However, these quantities do affect the allowable size of the remainder. For our second result, we assume the forcing is only bounded in time as a function into L2(W) . In this case, we need a smallness condition on the initial data, the forcing, and e to obtain global existence. The interesting observation is that the allowable sizes for the initial data and forcing grow as e-->0 . Thus, we obtain a `thin-domain' result as originally obtained by Raugel and Sell. In fact, our results allow the portion of the initial data and forcing independent of x3 to

  16. Modelling of the UO2 dissolution mechanisms in synthetic groundwater solutions. Dissolution experiments carried out under oxic conditions

    International Nuclear Information System (INIS)

    Cera, E.; Grive, M.; Bruno, J.; Ollila, K.

    2001-02-01

    The analytical data generated during the last three years within the 4th framework program of the European Community at VTT Chemical Technology concerning UO 2 dissolution under oxidising conditions have been modelled in the present work. The modelling work has been addressed to perform a kinetic study of the dissolution data generated by Ollila (1999) under oxidising conditions by using unirradiated uranium dioxide as solid sample. The average of the normalised UO 2 dissolution rates determined by using the initial dissolution data generated in all the experimental tests is (6.06 ± 3.64)* 10 -7 mol m -2 d -1 . This dissolution rate agrees with most of the dissolution rates reported in the literature under similar experimental conditions. The results obtained in this modelling exercise show that the same bicarbonate promoted oxidative dissolution processes operate for uranium dioxide, as a chemical analogue of the spent fuel matrix, independently of the composition of the aqueous solution used. (orig.)

  17. Hydrolysis and photolysis of diacylhydrazines-type insect growth regulator JS-118 in aqueous solutions under abiotic conditions.

    Science.gov (United States)

    Hu, J-Y; Liu, C; Zhang, Y-C; Zheng, Z-X

    2009-05-01

    JS-118 is a diacylhydrazines-type insect growth regulator which is now used extensively in China. The hydrolysis and photolysis of the pesticide JS-118 in aqueous solutions have been assessed under natural and controlled conditions in this project. Hydrolysis experimental results show that JS-118 is quite stable in aqueous solutions in dark, with no significant variations be observed in degradation under various conditions. Abiotic hydrolysis is relatively unimportant compared to photolysis. The rate of photodecomposition of JS-118 in aqueous solutions follows first-order kinetics both in UV radiation and natural sunlight. The degradation rates are faster under UV light than sunlight, with the half-lives (t (1/2) = ln2/k) of 6.00-10.85 min and 6.63-10.16 day, respectively. Under UV light, two major photoproducts are detected, and tentatively identified according to HPLC-MS spectral information as N-t-butyl-N-(3,5-dimethylbenzoyl) and 3,7-dimethyl-benzoatedihydrofuran. The corresponding photolysis pathways of JS-118 are also proposed. The results obtained indicate that direct photoreaction is an important dissipation pathway of JS-118 in natural water systems.

  18. Gold sorption from aqueous solutions by hydroxides and oxides at conditions of complex formation and oxidation-reduction

    International Nuclear Information System (INIS)

    Novikov, A.I.; Shekoturova, E.K.; Ribalko, T.A.

    1986-01-01

    With using of radionuclide 198 Au 3+ at initial form 198 AuCl 4 - the sorption of Au 3+ at its concentrations from 1.27·10 3 till 1.9·10 -9 mol/l from solutions of NaClO 4 (0.1 and 1 mol/l), KHO 3 (0.1 and 1 mol/l), NaNO 3 (1 mol/l), NaCl(0.7-3 mol/l), KCl(0.01; 0.1 and 1 mol/l), NH 4 NO 3 (0.1 and 1 mol/l)NH 4 Cl(10 -3 ; 10 -2 ; 10 -1 and 1 mol/l) in a wide ph range (0+14) by hydroxides of Fe(III), Zr, oxides of Fe(III), Ti(IV), Mn(IV) and Sn(IV) is studied. The dependences of sorption value of Au 3+ on ph of medium, composition and concentrations of electrolytes in solution are defined. Calculations on condition of Au 3+ in aqueous solutions are conducted. Optimal conditions of gold concentration (including 198 Au) and its separation from carrier at sorption process are defined as well.

  19. Thoracic radiotherapy in stereotactic conditions: difficulties met when starting up and proposed solutions; Radiotherapie thoracique en conditions stereotaxiques: difficultes rencontrees lors de la mise en route et solutions proposees

    Energy Technology Data Exchange (ETDEWEB)

    Halley, A.; Assouline, A.; Belghith, B.; Hemery, C.; Cuenca, X.; Lang, P.; Boisserie, G.; Simon, J.M.; Mazeron, J.J.; Feuvret, L. [Groupe hospitalier Pitie-Salpetriere, assistance Publique-Hopitaux de Paris, Paris (France)

    2011-10-15

    The authors report the study of difficulties met when starting up a thoracic irradiation in stereotactic conditions with respiratory feedback by means of a spirometry system. Eight patients have been selected. Images have been acquired in deep-inspiration breath-hold. Various dose levels have delivered in four sessions on the 80-per-cent isodose. It appears that this technique is constrained by the patient's physical capacities and the available technical means. Solutions are the use of a suitable support system, the screening of harmful positioning, and a training phase to respiratory feedback. Short communication

  20. Analytical Solution for Stress Field and Intensity Factor in CSTBD under Mixed Mode Conditions

    Directory of Open Access Journals (Sweden)

    Najaf Ali Ghavidel

    2014-06-01

    Full Text Available Considering the fact that rocks fail faster under tensile stress, rock tensile strength is of greatimportance in applications such as blasting, rock fragmentation, slope stability, hydraulic fracturing,caprock integrity, and geothermal energy extraction. There are two direct and indirect methods tomeasure tensile strength. Since direct methods always encompass difficulties in test setup, indirectmethods, specifically the Brazilian test, have often been employed for tensile strength measurement.Tensile failure is technically attributed to crack propagation in rock. Fracture mechanics hassignificant potential for the determination of crack behaviour as well as propagation pattern. To applyBrazilian tests, cracked disc geometry has been suggested by the International Society for RockMechanics ISRM. Accordingly, a comprehensive study is necessary to evaluate stress field and stressintensity factor (SIF around the crack in the centre of the specimen. In this paper, superpositionprinciple is employed to solve the problem of cracked straight-through Brazilian disc (CSTBD, usingtwo methods of dislocation and complex stress function. Stress field and SIF in the vicinity of thecrack tip are then calculated. With the proposed method, the magnitude of critical load for crackinitiation in structures can be predicted. This method is valid for any crack of any arbitrary length andangle. In addition, numerical modelling has been carried out for the Brazilian disc. Finally, theanalytical solution has been compared with numerical modelling results showing the same outcomefor both methods.

  1. Co-production of lipids, eicosapentaenoic acid, fucoxanthin, and chrysolaminarin by Phaeodactylum tricornutum cultured in a flat-plate photobioreactor under varying nitrogen conditions

    Science.gov (United States)

    Gao, Baoyan; Chen, Ailing; Zhang, Wenyuan; Li, Aifen; Zhang, Chengwu

    2017-10-01

    The marine diatom Phaeodactylum tricornutum is a polymorphological, ecologically significant, and well-studied model of unicellular microalga. This diatom can accumulate diverse important metabolites. Herein, we cultured P. tricornutum in an internally installed tie-piece flat-plate photobioreactor under 14.5 m mol L-1 (high nitrogen, HN) and 2.9 m mol L-1 (low nitrogen, LN) of KNO3 and assessed its time-resolved changes in biochemical compositions. The results showed that HN was inductive to accumulate high biomass (4.1 g L-1). However, the LN condition could accelerate lipid accumulation in P. tricornutum. The maximum total lipid (TL) content under LN was up to 42.5% of biomass on day 12. Finally, neutral lipids (NLs) were 63.8% and 75.7% of TLs under HN and LN, respectively. The content of EPA ranged from 2.3% to 1.5% of dry weight during the growth period under the two culture conditions. Peak volumetric lipid productivity of 128.4 mg L-1d-1 was achieved in the HN group (on day 9). The highest volumetric productivity values of EPA, chrysolaminarin, and fucoxanthin were obtained in the exponential phase (on day 6) under HN, which were 9.6, 93.6, and 4.7 mg L-1d-1, respectively. In conclusion, extractable amounts of lipids, EPA, fucoxanthin, and chrysolaminarin could be obtained from P. tricornutum by regulating the culture conditions.

  2. [Changes of vascular reactivity and reactive oxygen species in conditions of varying duration of permanent stay in the alienation zone in mice].

    Science.gov (United States)

    Tkachenko, M M; Kotsiuruba, A V; Baziliuk, O V; Horot', I V; Sahach, V F

    2010-01-01

    Peculiarities of changes in the vascular reactivity and in the content of reactive forms of oxygen and stable metabolites of nitric oxide (NO) were studied in the aorta preparations of C57BL/6 and BALB/c mice of the two age groups (6 and 18 mo.), which were born and permanently kept in the Chernobyl alienation zone. The results obtained showed a disturbance of acetylcholine-induced endothelium-dependent reactions of relaxation of smooth muscles of the thoracic aorta. A lower level of NO synthesis and lower level of oxidative arginase metabolism of arginine corresponded to a higher degree of damage of endothelium-dependent reactions of relaxation of the thoracic aorta smooth muscles. A decrease of NO synthesis in conditions of permanent effects of low doses of radiation was conditioned by an increase of generation of reactive forms of oxygen, namely, superoxide and hydroxyl radicals, which might be formed in mitochondria. In conditions of permanent effects of low doses of radiation a lesser level of protein nitrosothilation, same as lesser one of generation of OH-radical, corresponded to a higher level of damage of endothelium-dependent reactions.

  3. Weak solutions to the full Navier-Stokes-Fourier system with slip boundary conditions in time dependent domains

    Czech Academy of Sciences Publication Activity Database

    Kreml, Ondřej; Mácha, Václav; Nečasová, Šárka; Wróblewska-Kamińska, A.

    2018-01-01

    Roč. 109, January (2018), s. 67-92 ISSN 0021-7824 R&D Projects: GA ČR GA13-00522S; GA MŠk(CZ) 7AMB16PL060 Institutional support: RVO:67985840 Keywords : compressible Navier–Stokes–Fourier equations * time-varying domain * slip boundary conditions Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.802, year: 2016 http://www.sciencedirect.com/science/article/pii/S0021782417301381?via%3Dihub

  4. Weak solutions to the full Navier-Stokes-Fourier system with slip boundary conditions in time dependent domains

    Czech Academy of Sciences Publication Activity Database

    Kreml, Ondřej; Mácha, Václav; Nečasová, Šárka; Wróblewska-Kamińska, A.

    2018-01-01

    Roč. 109, January (2018), s. 67-92 ISSN 0021-7824 R&D Projects: GA ČR GA13-00522S; GA MŠk(CZ) 7AMB16PL060 Institutional support: RVO:67985840 Keywords : compressible Navier–Stokes–Fourier equations * time-varying domain * slip boundary conditions Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.802, year: 2016 http://www. science direct.com/ science /article/pii/S0021782417301381?via%3Dihub

  5. Perturbation methods and the Melnikov functions for slowly varying oscillators

    International Nuclear Information System (INIS)

    Lakrad, Faouzi; Charafi, Moulay Mustapha

    2005-01-01

    A new approach to obtaining the Melnikov function for homoclinic orbits in slowly varying oscillators is proposed. The present method applies the Lindstedt-Poincare method to determine an approximation of homoclinic solutions. It is shown that the resultant Melnikov condition is the same as that obtained in the usual way involving distance functions in three dimensions by Wiggins and Holmes [Homoclinic orbits in slowly varying oscillators. SIAM J Math Anal 1987;18(3):612

  6. K Basin Sludge Conditioning Process Testing Partitioning of PCBs in Dissolver Solution After Neutralization/Precipitation (Caustic Adjustment)

    International Nuclear Information System (INIS)

    Schmidt, A.J.; Thornton, B.M.; Hoppe, E.W.; Mong, G.M.; Silvers, K.L.; Slate, S.O.

    1999-01-01

    The purpose of the work described in this report was to gain a better understanding of how PCB congeners present in a simulated K Basin sludge dissolver solution will partition upon neutralization and precipitation (i.e., caustic adjustment). In a previous study (Mong et al. 1998),the entire series of sludge conditioning steps (acid dissolution, filtration, and caustic adjustment) were examined during integrated testing. In the work described here, the caustic adjustment step was isolated to examine the fate of PCBs in more detail within this processing step. For this testing, solutions of dissolver simulant (containing no solids) with a known initial concentration of PCB congeners were neutralized with caustic to generate a clarified supernatant and a settled sludge phase. PCBs were quantified in each phase (including the PCBs associated with the test vessel rinsates), and material balance information was collected

  7. Nonlinear reaction-diffusion systems conditional symmetry, exact solutions and their applications in biology

    CERN Document Server

    Cherniha, Roman

    2017-01-01

    This book presents several fundamental results in solving nonlinear reaction-diffusion equations and systems using symmetry-based methods. Reaction-diffusion systems are fundamental modeling tools for mathematical biology with applications to ecology, population dynamics, pattern formation, morphogenesis, enzymatic reactions and chemotaxis. The book discusses the properties of nonlinear reaction-diffusion systems, which are relevant for biological applications, from the symmetry point of view, providing rigorous definitions and constructive algorithms to search for conditional symmetry (a nontrivial generalization of the well-known Lie symmetry) of nonlinear reaction-diffusion systems. In order to present applications to population dynamics, it focuses mainly on two- and three-component diffusive Lotka-Volterra systems. While it is primarily a valuable guide for researchers working with reaction-diffusion systems  and those developing the theoretical aspects of conditional symmetry conception,...

  8. Growth kinetics and long-term stability of CdS nanoparticles in aqueous solution under ambient conditions

    International Nuclear Information System (INIS)

    Mullaugh, Katherine M.; Luther, George W.

    2011-01-01

    The ubiquity of naturally occurring nanoparticles in the aquatic environment is now widely accepted, but a better understanding of the conditions that promote their formation and persistence is needed. Using cadmium sulfide (CdS) as a model metal sulfide species, thiolate-capped CdS nanoparticles were prepared in the laboratory to evaluate how aquatic conditions influence metal sulfide nanoparticle growth and stability. This work examines CdS nanoparticle growth directly in aqueous solution at room temperature by utilizing the size-dependent spectroscopic properties of semiconductors detectable by UV/vis. CdS nanoparticle growth was governed by oriented attachment, a non-classical mechanism of crystallization in which small precursor nanoparticles coalesce to form larger nanoparticle products. Nanoparticle growth was slowed with increasing capping agent and decreasing ionic strength. In addition to examining the short-term (hours) growth of the nanoparticles, a long-term study was conducted in which cysteine-capped CdS nanoparticles were monitored over 3 weeks in solutions of various ionic strengths. The long-term study revealed an apparent shift from small nanoparticles to nanoparticles twice their original size, suggesting nanoparticle growth may continue through oriented attachment over longer time scales. High-ionic strength solutions resulted in salt-induced aggregation and eventual settling of nanoparticles within days, whereas low-ionic strength solutions were stable against settling over the course of the experiment. Sulfide recovery from cysteine-capped CdS nanoparticles as acid volatile sulfide was nearly quantitative after 2 weeks in fully oxygenated water, demonstrating significantly slowed oxidation of sulfide when complexed to Cd(II) within CdS nanoparticles. The nanoparticles were also shown to be resistant to oxidation by Fe(III) (hydr)oxide. This study illustrates that aggregation, rather than chemical oxidation, is likely more important to the

  9. Conditional Stability of Solitary-Wave Solutions for Generalized Compound KdV Equation and Generalized Compound KdV-Burgers Equation

    International Nuclear Information System (INIS)

    Zhang Weiguo; Dong Chunyan; Fan Engui

    2006-01-01

    In this paper, we discuss conditional stability of solitary-wave solutions in the sense of Liapunov for the generalized compound KdV equation and the generalized compound KdV-Burgers equations. Linear stability of the exact solitary-wave solutions is proved for the above two types of equations when the small disturbance of travelling wave form satisfies some special conditions.

  10. A new luminescence dating chronology for the Rhafas cave site (NE Morocco): Insights into Palaeolithic human cultural change under varying palaeoenvironmental conditions in the Maghreb

    Science.gov (United States)

    Dörschner, Nina; Fitzsimmons, Kathryn E.; Ditchfield, Peter; McLaren, Sue J.; Steele, Teresa E.; Zielhofer, Christoph; McPherron, Shannon P.; Bouzouggar, Abdeljalil; Hublin, Jean-Jacques

    2016-04-01

    Archaeological sites in northern Africa provide a rich record that is of increasing importance for current debates relating to the origins of modern human behaviour and to Out of Africa human dispersal events. Particular interest is placed on the cultural transition between the North African Middle Stone Age (MSA) and Late Stone Age (LSA), and the need for accurately defined chronologies, however the timing and nature of Palaeolithic human behaviour and dispersal across north-western Africa (the Maghreb) and potential correlation with environmental conditions remain poorly understood. The inland cave site of Rhafas (Morocco) preserves a long stratified sequence providing valuable chronological information about cultural changes in the Maghreb spanning the North African MSA through to the Neolithic. In this study, we apply optically stimulated luminescence (OSL) dating on sand-sized quartz grains to the cave deposits of Rhafas as well as to a section on the terrace in front of the cave entrance. Single grain OSL dating reliably constrains the timing of technocomplexes beyond the limits of radiocarbon by directly dating sediment associated with archaeological traces. We combine OSL dating with multi-proxy geological investigations (XRF, grain size analyses, stable isotopes, thin sections) to investigate site formation processes and reconstruct palaeoenvironmental conditions during human occupation phases at Rhafas. Our results indicate that the occupation of the site started at least in MIS 6 during a phase of relatively arid environmental conditions. Climatic amelioration after c.140 ka is associated with a change in sediment geochemistry at the site, most likely linked to a change in sediment source due to shifting wind directions. Tanged pieces - typical for the classical Aterian technocomplex - start to occur in the archaeological sequence in MIS 5, consistent with previously published chronological data from the Maghreb. From 55 ka, climatic conditions were

  11. A Comparative Study of Environmental Conditions, Bee Management and the Epidemiological Situation in Apiaries Varying in the Level of Colony Losses

    Directory of Open Access Journals (Sweden)

    Pohorecka Krystyna

    2014-12-01

    Full Text Available Explaining the reasons for the increased mortality of the honey bee (Apis mellifera L. in recent years, in Europe and North America, has become a global research priority in apicultural science. Our project was aimed at determining the relationship between environmental conditions, beekeeping techniques, the epidemiological situation of pathogens, and the mortality rate of bee colonies. Dead bee samples were collected by beekeepers from 2421 colonies. The samples were examined for the presence of V. destructor, Nosema spp. (Nosema apis and Nosema ceranae, chronic bee paralysis virus (CBPV, acute bee paralysis virus (ABPV, deformed wing virus (DWV, and Israeli acute paralysis virus (IAPV.

  12. Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

    Science.gov (United States)

    Shope, James B.; Storlazzi, Curt D.; Hoeke, Ron K.

    2017-10-01

    Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider

  13. Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands

    Science.gov (United States)

    Shope, James B.; Storlazzi, Curt; Hoeke, Ron

    2017-01-01

    Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider

  14. Numerical doubly-periodic solution of the (2+1)-dimensional Boussinesq equation with initial conditions by the variational iteration method

    International Nuclear Information System (INIS)

    Inc, Mustafa

    2007-01-01

    In this Letter, a scheme is developed to study numerical doubly-periodic solutions of the (2+1)-dimensional Boussinesq equation with initial condition by the variational iteration method. As a result, the approximate and exact doubly-periodic solutions are obtained. For different modulus m, comparison between the approximate solution and the exact solution is made graphically, revealing that the variational iteration method is a powerful and effective tool to non-linear problems

  15. Conditioned flavor avoidance as a measure of withdrawal in rats chronically exposed to a caffeine solution.

    Science.gov (United States)

    Dreumont-Boudreau, Sarah E; Dingle, Rachel N; Alcolado, Gillian M; Lolordo, Vincent M

    2008-09-03

    Rats were given 21 days of chronic oral caffeine. A novel flavor (Maintenance CS) was then paired with the continuation of caffeine, and a second flavor (Withdrawal CS) was paired with caffeine removal. Rats avoided the Withdrawal CS, and drank more of the Maintenance CS in a two-bottle test, suggesting that removing caffeine had induced withdrawal. The value of the Maintenance CS was investigated by comparing it to a novel flavor paired with water (Neutral CS). In a series of two-bottle tests, the Maintenance and Neutral CSs were equivalent when pitted against each other, and both were preferred to the Withdrawal CS. These results demonstrate that conditioned flavor avoidance is a useful procedure in assessing caffeine withdrawal, and by inference dependence, produced by chronic oral consumption.

  16. Shells and containers under complex impact shock conditions - a practical solution concept

    International Nuclear Information System (INIS)

    Krieg, R.

    2000-01-01

    Many practically relevant impact processes are not as hard as a projectile impact but calculation or experimental assessment are difficult. Recent experiments at Karlsruhe Research Center show that many of these processes are similar, independent of geometry and scale, even for complex geometries and conditions. The preconditions and scaling factors for transfer of the model results to real dimensions are presented, and experimental facilities for investigating liquid impact on container walls are described. The latter were originally developed for analyses of serious accidents in nuclear facilities but can be used for other purposes as well. Using a concrete example, it was shown that the load of liquid impact on a shell with relatively filigrane protruding structures is lower by a factor of 14 than the impact of a comparable solid [de

  17. Preliminary results from uranium/americium affinity studies under experimental conditions for cesium removal from NPP ''Kozloduy'' simulated wastes solutions

    International Nuclear Information System (INIS)

    Nikiforova, A.; Kinova, L.; Peneva, C.; Taskaeva, I.; Petrova, P.

    2005-01-01

    We use the approach described by Westinghouse Savannah River Company using ammonium molybdophosphate (AMP) to remove elevated concentrations of radioactive cesium to facilitate handling waste samples from NPP K ozloduy . Preliminary series of tests were carried out to determine the exact conditions for sufficient cesium removal from five simulated waste solutions with concentrations of compounds, whose complexing power complicates any subsequent processing. Simulated wastes solutions contain high concentrations of nitrates, borates, H 2 C 2 O 4 , ethylenediaminetetraacetate (EDTA) and Citric acid, according to the composition of the real waste from the NPP. On this basis a laboratory treatment protocol was created. This experiment is a preparation for the analysis of real waste samples. In this sense the results are preliminary. Unwanted removal of non-cesium radioactive species from simulated waste solutions was studied with gamma spectrometry with the aim to find a compromise between on the one hand the AMP effectiveness and on the other hand unwanted affinity to AMP of Uranium and Americium. Success for the treatment protocol is defined by proving minimal uptake of U and Am, while at the same time demonstrating good removal effectiveness through the use of AMP. Uptake of U and Am were determined as influenced by oxidizing agents at nitric acid concentrations, proposed by Savannah River National laboratory. It was found that AMP does not significantly remove U and Am when concentration of oxidizing agents is more than 0.1M for simulated waste solutions and for contact times inherent in laboratory treatment protocol. Uranium and Americium affinity under experimental conditions for cesium removal were evaluated from gamma spectrometric data. Results are given for the model experiment and an approach for the real waste analysis is chosen. Under our experimental conditions simulated wastes solutions showed minimal affinity to AMP when U and Am are most probably in

  18. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    International Nuclear Information System (INIS)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (R s ) was evaluated in microcosms containing −1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing R s values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM. - Highlights: ► We assessed the effect of TOC and stirring on pesticide sampling rates by POCIS. ► Total organic carbon (TOC) had no effect on the sampling rates. ► Water flow and stirring significantly increased the magnitude of the sampling rates. ► The sampling rates generated are directly applicable to field conditions. - This study provides POCIS sampling rates data that can be used to estimate freely dissolved concentrations of toxic pesticides in natural waters.

  19. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    Science.gov (United States)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (Rs) was evaluated in microcosms containing -1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing Rs values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM.

  20. A Mathematical Model of Hourly Solar Radiation in Varying Weather Conditions for a Dynamic Simulation of the Solar Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Taehong Sung

    2015-07-01

    Full Text Available A mathematical model of hourly solar radiation with weather variability is proposed based on the simple sky model. The model uses a superposition of trigonometric functions with short and long periods. We investigate the effects of the model variables on the clearness (kD and the probability of persistence (POPD indices and also evaluate the proposed model for all of the kD-POPD weather classes. A simple solar organic Rankine cycle (SORC system with thermal storage is simulated using the actual weather conditions, and then, the results are compared with the simulation results using the proposed model and the simple sky model. The simulation results show that the proposed model provides more accurate system operation characteristics than the simple sky model.

  1. LEGAL CONSCIOUSNESS OF YOUTH IN CONDITIONS OF VOCATIONAL EDUCATION: PROBLEMS AND SOLUTIONS

    Directory of Open Access Journals (Sweden)

    R. R. Kalinina

    2014-10-01

    Full Text Available Goal: to study peculiarities of legal consciousness among youth in conditions of vocational education in legal and non-legal fields.Methods and practices: empirical (Assessing moral development: dilemmas by L. Kohlberg, Practice of self-analysis diagnostics by A.V. Karpov, Test on legal and civic consciousness by L.A. Yasyukova, “Level of Subjective Control” methodology by E.F. Bazhin et al. and mathematical and statistical methods (descriptive, comparative, and cluster analyses.Result: Peculiarities of contents in legal consciousness and its regulatory function in students of legal and non-legal programs were identified. Three types of students were determined: those with non-formed legal consciousness, with formed legal consciousness and with formal legal consciousness; main directions for psychological and pedagogical work in the university to develop adequate legal consciousness in students of various fields were set.Applicability of results: results of the research can be applied when developing elective courses, extracurricular activities, strategy for character-building work of the university, both in training lawyers and other professionals.

  2. SQUEEZE-E: The Optimal Solution for Molecular Simulations with Periodic Boundary Conditions.

    Science.gov (United States)

    Wassenaar, Tsjerk A; de Vries, Sjoerd; Bonvin, Alexandre M J J; Bekker, Henk

    2012-10-09

    In molecular simulations of macromolecules, it is desirable to limit the amount of solvent in the system to avoid spending computational resources on uninteresting solvent-solvent interactions. As a consequence, periodic boundary conditions are commonly used, with a simulation box chosen as small as possible, for a given minimal distance between images. Here, we describe how such a simulation cell can be set up for ensembles, taking into account a priori available or estimable information regarding conformational flexibility. Doing so ensures that any conformation present in the input ensemble will satisfy the distance criterion during the simulation. This helps avoid periodicity artifacts due to conformational changes. The method introduces three new approaches in computational geometry: (1) The first is the derivation of an optimal packing of ensembles, for which the mathematical framework is described. (2) A new method for approximating the α-hull and the contact body for single bodies and ensembles is presented, which is orders of magnitude faster than existing routines, allowing the calculation of packings of large ensembles and/or large bodies. 3. A routine is described for searching a combination of three vectors on a discretized contact body forming a reduced base for a lattice with minimal cell volume. The new algorithms reduce the time required to calculate packings of single bodies from minutes or hours to seconds. The use and efficacy of the method is demonstrated for ensembles obtained from NMR, MD simulations, and elastic network modeling. An implementation of the method has been made available online at http://haddock.chem.uu.nl/services/SQUEEZE/ and has been made available as an option for running simulations through the weNMR GRID MD server at http://haddock.science.uu.nl/enmr/services/GROMACS/main.php .

  3. Analytic solutions to linear, time-dependent fission product deposition models for isothermal laminar, slug, or multiregion flow conditions

    International Nuclear Information System (INIS)

    Durkee, J.W. Jr.

    1983-01-01

    The time-dependent convective-diffusion equation with radioactive decay is solved analytically in axisymmetric cylindrical geometry for laminar and slug velocity profiles under isothermal conditions. Concentration dependent diffusion is neglected. The laminar flow solution is derived using the method of separation of variables and Frobenius' technique for constructing a series expansion about a regular singular point. The slug flow multiregion solution is obtained using the method of separation of variables. The Davidon Variable Metric Minimization algorithm is used to compute the coupling coefficients. These solutions, which describe the transport of fission products in a flowing stream, are then used to determine the concentration of radioactive material deposited on a conduit wall using a standard mass transfer model. Fission product deposition measurements for five diffusion tubes in a Fort St. Vrain High-Temperature Gas-Cooled reactor plateout probe are analyzed. Using single region slug and laminar models, the wall mass transfer coefficients, diffusion coefficients, and inlet concentrations are determined using least squares analysis. The diffusion coefficients and inlet concentrations are consistent between tubes. The derived diffusion coefficients and wall mass transfer coefficients are in relative agreement with known literature values

  4. Gravity with free initial conditions: A solution to the cosmological constant problem testable by CMB B -mode polarization

    Science.gov (United States)

    Totani, Tomonori

    2017-10-01

    In standard general relativity the universe cannot be started with arbitrary initial conditions, because four of the ten components of the Einstein's field equations (EFE) are constraints on initial conditions. In the previous work it was proposed to extend the gravity theory to allow free initial conditions, with a motivation to solve the cosmological constant problem. This was done by setting four constraints on metric variations in the action principle, which is reasonable because the gravity's physical degrees of freedom are at most six. However, there are two problems about this theory; the three constraints in addition to the unimodular condition were introduced without clear physical meanings, and the flat Minkowski spacetime is unstable against perturbations. Here a new set of gravitational field equations is derived by replacing the three constraints with new ones requiring that geodesic paths remain geodesic against metric variations. The instability problem is then naturally solved. Implications for the cosmological constant Λ are unchanged; the theory converges into EFE with nonzero Λ by inflation, but Λ varies on scales much larger than the present Hubble horizon. Then galaxies are formed only in small Λ regions, and the cosmological constant problem is solved by the anthropic argument. Because of the increased degrees of freedom in metric dynamics, the theory predicts new non-oscillatory modes of metric anisotropy generated by quantum fluctuation during inflation, and CMB B -mode polarization would be observed differently from the standard predictions by general relativity.

  5. Energetic solutions of Rock Sandpipers to harsh winter conditions rely on prey quality

    Science.gov (United States)

    Ruthrauff, Daniel R.; Dekinga, Anne; Gill, Robert E.; Piersma, Theunis

    2018-01-01

    's depauperate invertebrate predator community. Given the delicate balance between environmental and prey conditions that currently make Cook Inlet a viable wintering area for Rock Sandpipers, small variations in these variables may affect the suitability of the site in the future.

  6. A new medium for Caenorhabditis elegans toxicology and nanotoxicology studies designed to better reflect natural soil solution conditions.

    Science.gov (United States)

    Tyne, William; Lofts, Stephen; Spurgeon, David J; Jurkschat, Kerstin; Svendsen, Claus

    2013-08-01

    A new toxicity test medium for Caenorhabditis elegans is presented. The test solution is designed to provide a better representation of natural soil pore water conditions than currently available test media. The medium has a composition that can readily be modified to allow for studies of the influences of a range of environmentally relevant parameters on nematode biology and toxicology. Tests conducted in the new medium confirmed that nematodes' reproduction was possible at a range of solution pH levels, offering the potential to conduct toxicity studies under a variety of conditions. A test to establish silver nanoparticle and dissolved silver nitrate toxicity, a study type not feasible in M9 or agar media due to precipitation and nanoparticle agglomeration, indicated lower silver nanoparticle (median effective concentration [EC50] of 6.5 mg Ag/L) than silver nitrate (EC50 0.28 mg Ag/L) toxicity. Characterization identified stable nanoparticle behavior in the new test medium. Copyright © 2013 SETAC.

  7. Investigation of oil production conditions and production operation by solution gas drive in low permeable heterogeneous limestones

    Energy Technology Data Exchange (ETDEWEB)

    Lillie, W

    1966-04-01

    It was the purpose of this study to investigate the production of oil and gas from a low permeable heterogeneous limestone-reservoir by solution gas drive. The rock-samples were subjected to extensive petrolphysical analyses in order to characterize the pore structure of of the limestone material. Laboratory model flow tests were undertaken to outline in detail the production history during the pressure depletion process under reservoir conditions and by using original reservoir fluids. The experiments were carried out at different rates of pressure decline. It can be stated that the rate of pressure decline is the most important factor affecting the oil recovery and the development of the gas-oil-ratio in a model flow test. The present investigation leads to the following conclusion: It is posible to get reliable results which could be the base for a reservoir performance prediction only when the gas and oil phase are maintained at equilibrium conditions within the rock sample during the pressure decline. An additional calculation of the solution gas drive reservoir production history by the Tarner method shows a good agreement of the experimental and the calculated data. (40 refs.)

  8. First results on T91 claddings with and without modified FeCrAlY coatings exposed in PbBi under varying conditions

    International Nuclear Information System (INIS)

    Weisenburger, A.; Heinzel, A.; Miller, G.; Rousanov, A.

    2008-01-01

    It is well known that at temperatures above 500 deg C low activation austenitic steels suffer from severe corrosion in lead or lead-bismuth. Low activation martensitic steels instead form under similar conditions concerning temperature and oxygen content thick oxide scales that periodically may span off. Both groups of materials are therefore restricted to areas having lower temperature load. For parts that are intended to be used in high-temperature regions, like claddings, surface protection has to be applied. From gas turbines the role of elements forming thin stable oxide scales is well understood. The concept chosen here for thermally high loaded parts, the claddings, is the deposition of a FeCrAlY coating of about 30 vt,m thickness that is afterwards re-melted applying a pulsed electron beam (GESA). The beam energy is adjusted in a way to melt the entire coating together with a few thin region of the bulk to create a perfect intermixing at the boundary. This results in a new surface area of the cladding with an aluminium content of the order of 5 wt.% that will be sufficiently high to grow thin stable oxide scales. This concept is proven for austenitic cladding materials like 1.4970 as well as for martensitic ones like T91. In long-term corrosion tests the compatibility to Pb or PbBi, the resistance against corrosion and severe oxidation, was clearly demonstrated. No negative response of such a modified coating on the mechanical properties and the stability under irradiation has been observed as of yet. This paper will focus on the surface modification process, the corrosion results thus far obtained and on the evaluation of some mechanical properties. For example, the swelling of the fuel by irradiation will lead during operation to an increase of the internal pressure. This is simulated in experiments where an internal pressure of defined value was applied on T91 cladding tubes. The influence of flow velocity between to 3 m/s on the oxidation behaviour of T

  9. Aqueous dissolution of silver iodide and associated iodine release under reducing conditions with FeCl2 solution

    International Nuclear Information System (INIS)

    Inagaki, Yaohiro; Imamura, Toshitaka; Idemitsu, Kazuya; Arima, Tatsumi; Kato, Osamu; Nishimura, Tsutomu; Asano, Hidekazu

    2008-01-01

    An empirical and analytical study was performed on the aqueous dissolution of silver iodide (AgI) to release iodine under reducing conditions with Fe 2+ in order to understand the fundamental chemical and/or physical behavior of potential radioactive iodine waste forms under geological disposal conditions. Aqueous dissolution tests of AgI powder in FeCl 2 solutions (10 -6 M to 10 -3 M) were performed in a glove box purged with a gas mixture (Ar + 5% H 2 ). The test results showed that AgI dissolves to release iodine at extremely slow rates, being controlled by a diffusion process in any FeCl 2 solution. The comparison with thermodynamic calculations based on redox equilibria suggested that the AgI dissolution proceeds by redox reaction between Ag + and Fe 2+ ; however, it was far from the thermodynamic equilibrium. These results suggested that the form of AgI itself has a potential to immobilize iodine for a long time even under the disposal conditions. Solid-phase analysis for the reacted AgI by using SEM/EDS showed a certain amount of silver (maybe metallic silver) precipitated at the surface. On the basis of these results and discussion, a potential mechanism for the actual AgI dissolution was proposed as follows. The AgI dissolution proceeds by redox reaction between Ag + and Fe 2+ to release I - , which results in the precipitation of metallic silver as a reduction product of Ag + at the AgI surface to form a thin layer covering the AgI surface. The silver layer evolves to be protective against the transport of reactant species, by which the further dissolution to reach the equilibrium is suppressed. Consequently, the dissolution proceeds at extremely slow rates, being controlled by a diffusion process. (author)

  10. Technology-derived storage solutions for stabilizing insulin in extreme weather conditions I: the ViViCap-1 device.

    Science.gov (United States)

    Pfützner, Andreas; Pesach, Gidi; Nagar, Ron

    2017-06-01

    Injectable life-saving drugs should not be exposed to temperatures 30°C/86°F. Frequently, weather conditions exceed these temperature thresholds in many countries. Insulin is to be kept at 4-8°C/~ 39-47°F until use and once opened, is supposed to be stable for up to 31 days at room temperature (exception: 42 days for insulin levemir). Extremely hot or cold external temperature can lead to insulin degradation in a very short time with loss of its glucose-lowering efficacy. Combined chemical and engineering solutions for heat protection are employed in ViViCap-1 for disposable insulin pens. The device works based on vacuum insulation and heat consumption by phase-change material. Laboratory studies with exposure of ViViCap-1 to hot outside conditions were performed to evaluate the device performance. ViViCap-1 keeps insulin at an internal temperature phase-change process and 'recharges' the device for further use. ViViCap-1 performed within its specifications. The small and convenient device maintains the efficacy and safety of using insulin even when carried under hot weather conditions.

  11. Extravasation injury of balanced electrolyte solution simulates the clinical condition of necrotizing fasciitis: A case report

    Directory of Open Access Journals (Sweden)

    Carmine D'Acunto

    2015-10-01

    Full Text Available Extravasation injury (EI is an iatrogenic condition that occurs preferentially in neonatal and pediatric patients when the injection of fluid substances by intravenous access is required and it accidentally leaks into the adjacent tissues or in spaces outside of vascular compartment. Different types and amount of substances once undergoing extravasation can affect the EI differently [1]. In some instances immediate measures such as saline washout, local antidotes, enzymatic debridement and surgical interventions can be required in order to prevent the occurrence of a growing injury avoiding the progression of the EI to a medical emergency [6]. Here we report an unusual case of a preterm 2-month-old male patient in which the extravasation of balanced electrolyte solution on the upper right arm resulted in the development of full-thickness skin necrosis appearing as the clinical condition of necrotizing fasciitis. The management of necrotic tissue was performed using escharectomy as well as autograft skin under conditions of general anesthesia.

  12. UO2 leaching and radionuclide release modelling under high and low ionic strength solution and oxidation conditions

    International Nuclear Information System (INIS)

    1995-01-01

    In this work, the UO 2 dissolution under oxidizing conditions has been studied in order to compare these results to those obtained with spent fuel. Two different leaching solutions have been used, one with a high ionic strength trying to simulate the conditions expected in a saline repository and the other at low ionic strength much appropriate to granitic environments. In both cases, the dissolution has been studied studied as a function of pH, redox potential, oxidants, complexing agents, particle size as well as the experimental methodology. Results can be summarized as follows: a) The UO 2 dissolution is rather independent on ionic strength. b) Dissolution rates can be explained in general independent on the oxidant as: Log R=3DK [oxidant] Surface solid evolution is very important to understand the dissolution/oxidation mechanism of UO 2 . d) Under oxidizing conditions, the dissolution is H+ and HCO 3 promoted. e) In carbonate medium, both UO 2 and spent fuel dissolution rates are very similar, while in a non-complexing medium, spent fuel dissolution rate is much higher than the UO 2 one. This fact seems to indicate that radiolysis is much important non-complexing media. (Author)

  13. Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

    Directory of Open Access Journals (Sweden)

    J. K. Koestel

    2012-06-01

    Full Text Available Preferential flow is a widespread phenomenon that is known to strongly affect solute transport in soil, but our understanding and knowledge is still poor of the site factors and soil properties that promote it. To investigate these relationships, we assembled a database from the peer-reviewed literature containing information on 733 breakthrough curve experiments under steady-state flow conditions. Most of the collected experiments (585 of the 733 datasets had been conducted on undisturbed soil columns, although some experiments on repacked soil, clean sands, and glass beads were also included. In addition to the apparent dispersivity, we focused our attention on three indicators of preferential solute transport: namely the 5%-arrival time, the holdback factor, and the ratio of piston-flow and average transport velocities. Our results suggest that, in contrast to the 5%-arrival time and the holdback factor, the piston-flow to transport velocity ratio is not related to preferential macropore transport but rather to the exclusion or retardation of the applied tracer. Confirming that the apparent longitudinal dispersivity is positively correlated with the travel distance of the tracer, our results also illustrate that this relationship is refined if the normalized 5%-tracer arrival time is also taken into account. In particular, we found that the degree of preferential solute transport increases with apparent dispersivity and decreases with travel distance. A similar but weaker relationship was observed between apparent dispersivity, 5%-tracer arrival time, and lateral observation scale, such that the degree of preferential transport increases with lateral observation scale. However, we also found that the travel distance and the lateral observation scale in the investigated dataset are correlated, which makes it difficult to distinguish their influence on these transport characteristics. We also found that the strength of preferential transport

  14. Evaluation of the Ross fast solution of Richards' equation in unfavourable conditions for standard finite element methods

    International Nuclear Information System (INIS)

    Crevoisier, D.; Voltz, M.; Chanzy, A.

    2009-01-01

    Ross [Ross PJ. Modeling soil water and solute transport - fast, simplified numerical solutions. Agron J 2003;95:1352-61] developed a fast, simplified method for solving Richards' equation. This non-iterative 1D approach, using Brooks and Corey [Brooks RH, Corey AT. Hydraulic properties of porous media. Hydrol. papers, Colorado St. Univ., Fort Collins: 1964] hydraulic functions, allows a significant reduction in computing time while maintaining the accuracy of the results. The first aim of this work is to confirm these results in a more extensive set of problems, including those that would lead to serious numerical difficulties for the standard numerical method. The second aim is to validate a generalisation of the Ross method to other mathematical representations of hydraulic functions. The Ross method is compared with the standard finite element model, Hydrus-1D [Simunek J, Sejna M, Van Genuchten MTh. The HYDRUS-1D and HYDRUS-2D codes for estimating unsaturated soil hydraulic and solutes transport parameters. Agron Abstr 357; 1999]. Computing time, accuracy of results and robustness of numerical schemes are monitored in 1D simulations involving different types of homogeneous soils, grids and hydrological conditions. The Ross method associated with modified Van Genuchten hydraulic functions [Vogel T, Cislerova M. On the reliability of unsaturated hydraulic conductivity calculated from the moisture retention curve. Transport Porous Media 1988:3:1-15] proves in every tested scenario to be more robust numerically, and the compromise of computing time/accuracy is seen to be particularly improved on coarse grids. Ross method run from 1.25 to 14 times faster than Hydrus-1D. (authors)

  15. Joint route planning under varying market conditions

    NARCIS (Netherlands)

    Cruijssen, Frans; Bräysy, Olli; Dullaert, Wout; Fleuren, Hein; Salomon, Marc

    2007-01-01

    Purpose - To provide empirical evidence on the level of savings that can be attained by joint route planning and how these savings depend on specific market characteristics. Design/methodology/approach - Joint route planning is a measure that companies can take to decrease the costs of their

  16. Transport of solutes under transient flow conditions – A case study – Yamuna river sub basin (Kosi Kalan to Agra

    Directory of Open Access Journals (Sweden)

    Arun Kumar

    2015-09-01

    Full Text Available The imbalance between incoming and outgoing salt causes salinization of soils and sub-soils that result in increasing the salinity of stream-flows and agriculture land. This salinization is a serious environmental hazard particularly in semi-arid and arid lands. In order to estimate the magnitude of the hazard posed by salinity, it is important to understand and identify the processes that control salt movement from the soil surface through the root zone to the ground water and stream flows. In the present study, Yamuna sub-basin (both sides of Gokul dam site has been selected which has two distinct climatic zones, sub-humid (upstream of Mathura and semi-arid region (downstream of Mathura. In the upstream, both surface and ground waters are used for irrigation, whereas in the downstream mostly groundwater is used. Both soils and ground waters are more saline in downstream parts of the study area. In this study we characterized the soil salinity and groundwater quality in both areas. An attempt is also made to model the distribution of potassium concentration in the soil profile in response to varying irrigation conditions using the Soil-Water Infiltration and Movement (SWIM model. Fair agreement was obtained between predicted and measured results indicating the applicability of the model.

  17. Homogenous UV/periodate process in treatment of p-nitrophenol aqueous solutions under mild operating conditions.

    Science.gov (United States)

    Saien, Javad; Fallah Vahed Bazkiaei, Marzieh

    2018-07-01

    Aqueous solutions of p-nitrophenol (PNP) were treated with UV-activated potassium periodate (UV/KPI) in an efficient photo-reactor. Either periodate or UV alone had little effect; however, their combination led to a significant degradation and mineralization. The response surface methodology was employed for design of experiments and optimization. The optimum conditions for treatment of 30 mg/L of the substrate were determined as [KPI] = 386.3 mg/L, pH = 6.2 and T = 34.6°C, under which 79.5% degradation was achieved after 60 min. Use of 25 and 40 kHz ultrasound waves caused the degradation to enhance to 88.3% and 92.3%, respectively. The intermediates were identified by gas chromatography-mass spectroscopy analysis, leading to propose the reaction pathway. The presence of water conventional bicarbonate, chloride, sulfate and nitrate anions caused unfavorable effects in efficiency. Meanwhile, the kinetic study showed that PNP degradation follows a pseudo-first-order reaction and the activation energy was determined. The irradiation energy consumption required for one order of magnitude degradation was estimated as 11.18 kWh/m 3 . Accordingly, comparison with the previously reported processes showed the superiority of PNP treatment with the employed process.

  18. Analytical Solution of Heat Conduction for Hollow Cylinders with Time-Dependent Boundary Condition and Time-Dependent Heat Transfer Coefficient

    Directory of Open Access Journals (Sweden)

    Te-Wen Tu

    2015-01-01

    Full Text Available An analytical solution for the heat transfer in hollow cylinders with time-dependent boundary condition and time-dependent heat transfer coefficient at different surfaces is developed for the first time. The methodology is an extension of the shifting function method. By dividing the Biot function into a constant plus a function and introducing two specially chosen shifting functions, the system is transformed into a partial differential equation with homogenous boundary conditions only. The transformed system is thus solved by series expansion theorem. Limiting cases of the solution are studied and numerical results are compared with those in the literature. The convergence rate of the present solution is fast and the analytical solution is simple and accurate. Also, the influence of physical parameters on the temperature distribution of a hollow cylinder along the radial direction is investigated.

  19. Generalized boundary conditions in an existence and uniqueness proof for the solution of the non-stationary electron Boltzmann equation by means of operator-semigroups

    International Nuclear Information System (INIS)

    Bartolomaeus, G.; Wilhelm, J.

    1983-01-01

    Recently, based on the semigroup approach a new proof was presented of the existence of a unique solution of the non-stationary Boltzmann equation for the electron component of a collision dominated plasma. The proof underlies some restriction which should be overcome to extend the validity range to other problems of physical interest. One of the restrictions is the boundary condition applied. The choice of the boundary condition is essential for the proof because it determines the range of definition of the infinitesimal generator and thus the operator semigroup itself. The paper proves the existence of a unique solution for generalized boundary conditions, this solution takes non-negative values, which is necessary for a distribution function from the physical point of view. (author)

  20. Existence of solutions for a fourth order eigenvalue problem ] {Existence of solutions for a fourth order eigenvalue problem with variable exponent under Neumann boundary conditions

    Directory of Open Access Journals (Sweden)

    Khalil Ben Haddouch

    2016-04-01

    Full Text Available In this work we will study the eigenvalues for a fourth order elliptic equation with $p(x$-growth conditions $\\Delta^2_{p(x} u=\\lambda |u|^{p(x-2} u$, under Neumann boundary conditions, where $p(x$ is a continuous function defined on the bounded domain with $p(x>1$. Through the Ljusternik-Schnireleman theory on $C^1$-manifold, we prove the existence of infinitely many eigenvalue sequences and $\\sup \\Lambda =+\\infty$, where $\\Lambda$ is the set of all eigenvalues.

  1. A brief review of soil water, solute transport and regionalized variable analysis Uma breve revisão de água no solo, transporte de soluto e análise de variável regionalizada

    Directory of Open Access Journals (Sweden)

    D.R. Nielsen

    1997-06-01

    Full Text Available We initially review basic concepts of the forces acting on soil water, soil water potential and soil water retention, and equations to describe soil water movement under water-saturated and unsaturated conditions. Processes of infiltration, evaporation and redistribution of water will be presented for simple initial and boundary conditions occurring within homogeneous soil columns. Next we consider the physical, chemical and biological processes within a soil profile that distribute, dilute or concentrate solute species within the liquid phase of a soil The relative concentration of solutes in the liquid phase governs not only the retention and transport of water within soils but also contributes to our understanding of managing the quality of water within soils and that moving below the recall of plant roots deeper into the vadose zone. A complete set of references about this subject is available in Kutílek & Nielsen (1994. In the last section we recall the differences between classical statistical concepts and those that utilize the coordinates of space and time at which state variables across the landscape are observed. Our presentation win cover the basic ideas about autocorrelation, crosscorrelation, applied time series analyses, state space analyses and similar techniques currently being used to enhance field research and investigations of land and water management.Inicialmente foram revisados os conceitos básicos das forcas que atuam sobre a água no solo, potencial e retenção de água no solo, e as equações que descrevem o movimento de água sob condições de solos saturados e não saturados. Os processos de infiltração, evaporação e redistribuição de água foram apresentados para condições inicial e de contorno que ocorrem dentro de colunas de solo homogêneo. Posteriormente, foram considerados os processos físicos, químicos e biológicos dentro de um perfil do solo que distribuem, diluem ou concentram espécies de

  2. Proof of existence of global solutions for m-component reaction-diffusion systems with mixed boundary conditions via the Lyapunov functional method

    International Nuclear Information System (INIS)

    Abdelmalek, Salem; Kouachi, Said

    2007-01-01

    To prove global existence for solutions of m-component reaction-diffusion systems presents fundamental difficulties in the case in which some components of the system satisfy Neumann boundary conditions while others satisfy nonhomogeneous Dirichlet boundary conditions and nonhomogeneous Robin boundary conditions. The purpose of this paper is to prove the existence of a global solution using a single inequality for the polynomial growth condition of the reaction terms. Our technique is based on the construction of polynomial functionals. This result generalizes those obtained recently by Kouachi et al (at press), Kouachi (2002 Electron. J. Diff. Eqns 2002 1), Kouachi (2001 Electron. J. Diff. Eqns 2001 1) and independently by Malham and Xin (1998 Commun. Math. Phys. 193 287)

  3. Nucleation of CaCO3 polymorphs from a colloidal alcoholic solution of Ca(OH)2 nanocrystals exposed to low humidity conditions

    OpenAIRE

    Gómez Villalba, Luz Stella; López-Arce, Paula; Fort González, Rafael

    2011-01-01

    A study of the stability of calcium carbonate polymorphs formed as a result of the carbonation process from an alcoholic colloidal solution of nanocrystals of Ca(OH)2 in low relative humidity (RH) conditions (33% and 54% RH) is presented in this research. The crystalline behavior, the time dependence of nucleation and the phases’ transformations as a result of exposure to low humidity conditions are evaluated. The carbonation process is slow, starting with the nucleation of amorphous calcium ...

  4. The flux pinning properties of BaSnO{sub 3}-added GdBa{sub 2}Cu3O{sub 7-δ} films with varying growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. K.; Oh, J. Y.; Kang, B. [Dept. of Physics, Chungbuk National University, Cheongju (Korea, Republic of); Lee, J. M.; Kang, W. N. [Dept. of Physics, Sungkyunkwan University, Suwon (Korea, Republic of)

    2017-09-15

    Addition of BaSnO{sub 3} (BSO) to GdBa{sub 2}Cu{sub 3}O{sub 7-δ} (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to 750 ℃ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

  5. Analysis of an Air Conditioning Coolant Solution for Metal Contamination Using Atomic Absorption Spectroscopy: An Undergraduate Instrumental Analysis Exercise Simulating an Industrial Assignment

    Science.gov (United States)

    Baird, Michael J.

    2004-01-01

    A real-life analytical assignment is presented to students, who had to examine an air conditioning coolant solution for metal contamination using an atomic absorption spectroscopy (AAS). This hands-on access to a real problem exposed the undergraduate students to the mechanism of AAS, and promoted participation in a simulated industrial activity.

  6. Existence of 2m-1 Positive Solutions for Sturm-Liouville Boundary Value Problems with Linear Functional Boundary Conditions on the Half-Line

    Directory of Open Access Journals (Sweden)

    Yanmei Sun

    2012-01-01

    Full Text Available By using the Leggett-Williams fixed theorem, we establish the existence of multiple positive solutions for second-order nonhomogeneous Sturm-Liouville boundary value problems with linear functional boundary conditions. One explicit example with singularity is presented to demonstrate the application of our main results.

  7. The Effect of Potassium Concentration in Nutrient Solution on Lycopene, Vitamin C and Qualitative Characteristics of Cherry Tomato in Saline Conditions

    Directory of Open Access Journals (Sweden)

    E. Shabani Sangtarashani

    2013-06-01

    Full Text Available Potassium (K has a special place in improving the quality of agricultural products. To evaluate the effect of K concentration in nutrient solution on lycopene content, vitamin C and qualitative characteristics of cherry tomato in NaCl salinity conditions, an experiment was carried out as a completely randomized design with five treatments and three replications at university of Tabriz, Tabriz, Iran, in 2010. Treatments consisted of four concentrations of K (0.2, 2, 7 and 14 mM in nutrient solution with 60 mM NaCl concentration. A nutrient solution treatment without salinity was considered as control. The experiment was conducted in greenhouse, in a hydroponic system. The results indicated that increasing of K concentration increased lycopene content in fruit. Lycopene content in control treatment showed significant difference (P<0.01 in comparison with salinity treatments. With increasing the K concentration (except at 14 mM concentration, vitamin C content was increased, but indicated no statistically significant difference. Vitamin C content in saline conditions was more than control treatment, but showed no significant difference. Adding potassium concentration in nutrient solution improved yield and enhanced quality parameters such as percentage of dry matter, soluble solids and electrical conductivity of fruit extract. Since in saline conditions, the qualitative characteristics of tomato at 7 mM concentration were in the best situation, therefore using this concentration is recommended.

  8. Transport of E. coli D21g with runoff water under different solution chemistry conditions and surface slopes

    Science.gov (United States)

    Tracer and indicator microbe runoff experiments were conducted to investigate the influence of solution chemistry on the transport, retention, and release of Escherichia coli D21g. Experiments were conducted in a chamber (2.25 m long, 0.15 m wide, and 0.16 m high) packed with ultrapure quartz sand (...

  9. Anti radiation action of 'Vin-Vita' food additive solution in 'Kuyalnik' mineral water under sublethal gamma-irradiation conditions

    International Nuclear Information System (INIS)

    Baraboj, V.A.; Lobasyuk, B.O.; Oleksyijenko, N.O.; Kujev, V.L.; Goncharov, M.Yi.; Smul's'kij, S.P.; Kolker, Yi.A.; Babov, K.D.

    1996-01-01

    The study involved four groups of female Wistar rats. Protective anti radiation action of 'Vin-Vita' food additive solution in 'Kuyalnik' mineral water especially in the concentration of 500 mg/l has been revealed, which was proved by hemoglobin, hematocrit, ESR, white blood parameters and animal behaviour

  10. Evaluation des performances de la production de graines par tamisage manuel du sol chez trois variétés de Stylosanthes guianensis (Aublet Swartz, dans les conditions du Plateau des Batéké (RDC

    Directory of Open Access Journals (Sweden)

    Bulakali, BP.

    2013-01-01

    Full Text Available Performance Assessment of the Production of Seeds by Manual Sieving of the Soil of Three Varieties of Stylosanthes guianensis (Aublet Swartz under the Conditions of the Batéké Plateau (DRC. In manual agriculture with low resources level, Stylosanthes guianensis is one of the most interesting cover crop for developing direct seeding mulch-based cropping systems. To promote its cultivation in the DRC, the performances of a seed production method by sieving of the soil were evaluated for three varieties of Stylo (a local ecotype, CIAT 184 variety, and 202cc variety in two sites of the Batéké plateau characterized by contrasted fertility levels. The results obtained demonstrate the interest of the seed multiplication method tested, both in quantities and quality of the produced seeds. The production cost of one kg of seeds varies with the soil fertility, the planting date, and the cultivar. Among the three compared varieties, CIAT 184 variety produced the highest quantity of seeds. If sown at the beginning of the long rainy season, after a long fallow, in one of the most fertile soils of the plateau, this cultivar can produce 600 kg ha-1 seed in the first year of cultivation with a production cost of USD 1.31 kg-1, equivalent to less than 0.5 man.day.kg-1.

  11. Concentrated Aqueous Sodium Chloride Solution in Clays at Thermodynamic Conditions of Hydraulic Fracturing: Insight from Molecular Dynamics Simulations.

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Martin; Lísal, Martin

    2018-01-01

    Roč. 148, č. 22 (2018), č. článku 222806. ISSN 0021-9606 R&D Projects: GA ČR GA17-25100S EU Projects: European Commission(XE) 640979 - ShaleXenvironmenT Institutional support: RVO:67985858 Keywords : aqueous NaCl solutions * hydrogen bond networks * molecular dynamics simulations Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.965, year: 2016

  12. Lazer-Leach Type Conditions on Periodic Solutions of Liénard Equation with a Deviating Argument at Resonance

    OpenAIRE

    Wang, Zaihong

    2013-01-01

    We study the existence of periodic solutions of Liénard equation with a deviating argument $x\\mathrm{\\prime \\prime }+f\\left(x\\right)x\\mathrm{\\text{'}}+{n}^{\\mathrm{2}}x+g\\left(x\\left(t-\\tau \\right)\\right)=p\\left(t\\right),$ where $f,g,p:\\mathrm{R}\\to \\mathrm{R}$ are continuous and $p$ is $\\mathrm{2}\\pi $ -periodic, $\\mathrm{0}\\le \\tau

  13. The analytical solution to the problem on the temperature field in a structural element of rectangular profile for third kind boundary conditions

    International Nuclear Information System (INIS)

    Kulich, N.V.; Nemtsev, V.A.

    1986-01-01

    The analytical solution to the problem on the stationary temperature field in an infinite structural element of rectangular profile characteristic of the conjugation points of a vessel and a tube sheet of a heat exchanger (or of a finned surface) at the third-kind boundary conditions has been obtained by the methods of the complex variable function theory. With the help of the obtained analytical dependences the calculations of the given element of the design and the comparison with the known data have been conducted. The proposed analytical solution can be effectively used in calculations of temperature fields in finned surfaces and structural elements of the power equipment of the considered profile and the method is applied for solution of the like problems

  14. Avaliação de variáveis fisiológicas em porta-enxertos de videira cultivados em solução nutritiva com a adição de alumínio Physiologic variables evaluation in grapevine roostocks grown in nutritive solution with aluminum addition

    Directory of Open Access Journals (Sweden)

    Marco Antonio Tecchio

    2005-04-01

    Full Text Available Realizou-se este experimento com o objetivo de avaliar a resposta dos porta-enxertos de videira IAC 313 "Tropical" e IAC 572 "Jales" a diferentes níveis de alumínio em solução nutritiva. A condução do experimento foi realizada em condições de casa-de-vegetação do Departamento de Produção Vegetal/Área de Horticultura, da Faculdade de Ciências Agronômicas - UNESP/Botucatu. Utilizaram-se cinco níveis de alumínio, a saber: 0, 10, 20, 30 e 40 mg L-1. Após a aplicação dos tratamentos, realizaram-se coletas a cada 15 dias para obtenção das variáveis fisiológicas. O delineamento experimental adotado foi o de parcelas subdivididas, inteiramente casualizado e com 3 repetições. Avaliaram-se as variáveis: taxa de crescimento absoluto e relativo, razão de massa foliar e relação parte aérea/raízes. Concluiu-se que o porta-enxerto IAC 572 "Jales", quando submetido ao nível de 10mg Al L-1 na solução, apresentou maior taxa de crescimento absoluto e relativo, e maior redistribuição de massa seca das folhas para o restante da planta, ao passo que o porta-enxerto IAC 313 "Tropical", quando submetido a esse nível de alumínio, apresentou um decréscimo acentuado nessas variáveis.The experiment aimed to evaluate the behavior of the grapevine rootstocks IAC 313 "Tropical" and IAC 572 "Jales" in nutrient solution with different aluminium concentrations. The experiment was conducted in green house conditions of the Vegetal Production Department/Horticulture Sector, of the Faculty of Agricultural Sciences - UNESP/Botucatu. Five aluminium levels were used, as known: 0, 10, 20, 30 and 40mg L-1in the form of AlCl3.6H2O. The samples were colleted every 15 days to obtain the physiologic variables. The experimental design adopted was the subdivided split-plots, fully randomized and with 3 replications. The variables evaluated were: absolute and relative growth rates, leaf weight and aerial parts/root ratio. The IAC 572 "Jales" rootstock

  15. Lie and Q-Conditional Symmetries of Reaction-Diffusion-Convection Equations with Exponential Nonlinearities and Their Application for Finding Exact Solutions

    Directory of Open Access Journals (Sweden)

    Roman Cherniha

    2018-04-01

    Full Text Available This review is devoted to search for Lie and Q-conditional (nonclassical symmetries and exact solutions of a class of reaction-diffusion-convection equations with exponential nonlinearities. A complete Lie symmetry classification of the class is derived via two different algorithms in order to show that the result depends essentially on the type of equivalence transformations used for the classification. Moreover, a complete description of Q-conditional symmetries for PDEs from the class in question is also presented. It is shown that all the well-known results for reaction-diffusion equations with exponential nonlinearities follow as particular cases from the results derived for this class of reaction-diffusion-convection equations. The symmetries obtained for constructing exact solutions of the relevant equations are successfully applied. The exact solutions are compared with those found by means of different techniques. Finally, an application of the exact solutions for solving boundary-value problems arising in population dynamics is presented.

  16. Steady state solution of the Fokker-Planck equation combined with unidirectional quasilinear diffusion under detailed balance conditions

    International Nuclear Information System (INIS)

    Hizanidis, K.

    1984-04-01

    The relativistic collisional Fokker-Planck equation combined with an externally imposed unidirectional quasilinear (rf) diffusion is solved for arbitrary values of rf diffusion coefficient under conditions of detailed balance of the staionary joint distribution involved. The detailed balance condition imposes a restriction on the functional form of the quasilinear diffusion coefficient which might be associated with the existence of a saturated spectrum of fluctuation in a quasilinearly rf-driven plasma

  17. Task reports on developing techniques for scattering by 3D composite structures and to generate new solutions in diffraction theory using higher order boundary conditions

    Science.gov (United States)

    Volakis, John L.

    1991-01-01

    There are two tasks described in this report. First, an extension of a two dimensional formulation is presented for a three dimensional body of revolution. A Fourier series expansion of the vector electric and magnetic fields is employed to reduce the dimensionality of the system, and an exact boundary condition is employed to terminate the mesh. The mesh termination boundary is chosen such that it leads to convolutional boundary operators for low O(n) memory demand. Second, rigorous uniform geometrical theory of diffraction (UTD) diffraction coefficients are presented for a coated convex cylinder simulated with generalized impedance boundary conditions. Ray solutions are obtained which remain valid in the transition region and reduce uniformly those in the deep lit and shadow regions. A uniform asymptotic solution is also presented for observations in the close vicinity of the cylinder.

  18. Differential pharmacokinetics of diclofenac potassium for oral solution vs immediate-release tablets from a randomized trial: effect of fed and fasting conditions.

    Science.gov (United States)

    Chen, Cuiping; Bujanover, Shay; Kareht, Stephanie; Rapoport, Alan M

    2015-02-01

    analyzed for diclofenac concentrations. Pharmacokinetic parameters, including peak concentration (Cmax ), time to Cmax (tmax ), area under the concentration-time curve (AUC) from time 0 to last measurable concentration (AUCt ), and extrapolation to infinity (AUC∞ ) were obtained using non-compartmental analysis. Comparative assessments for Cmax and AUC were performed between the solution and tablet under fed and fasting conditions and between fed and fasting states for both formulations. Bioequivalent exposure was defined as the geometric mean ratio and its 90% confidence interval falling within 80.0-125.0% for Cmax and AUC. Adverse events (AEs) were monitored throughout the trial. Sixty-one percent of the 36 randomized subjects were male, 91.7% were Caucasian, and the mean (standard deviation [SD]) age was 31.9 (7.6) years. Thirty-three (91.7%) subjects completed all 4 treatments. When taken under fed conditions, the oral solution resulted in an approximately 80% faster median tmax (0.17 vs 1.25 hours, P = .00015) and a 21% lower Cmax (mean ± SD, ng/mL: 506 ± 305 vs 835 ± 449, P = .00061) compared with the tablet. AUC values were similar between the 2 formulations. When taken under fasting conditions, the oral solution exhibited a 50% faster median tmax (0.25 vs 0.50 hours, P = .00035) to achieve a 77% higher Cmax (mean ± SD, ng/mL: 1620 ± 538 vs 1160 ± 452, P = .00032) compared with the tablet. AUCt and AUC∞ were similar between the 2 formulations. When taken under fed conditions, the oral solution resulted in a similar median tmax (0.17 vs 0.25 hours, P = .185) and 64% lower Cmax (mean ± SD, ng/mL: 506 ± 305 vs 1620 ± 538, P fasting conditions. In comparison, the tablets under fed conditions resulted in a statistically significantly delayed median tmax (1.25 vs 0.50, P = .00143) and ∼30% lower Cmax (mean ± SD, ng/mL: 835 ± 449 vs 1160 ± 452, P = .00377). AUC values were

  19. On a strong solution of the non-stationary Navier-Stokes equations under slip or leak boundary conditions of friction type

    Science.gov (United States)

    Kashiwabara, Takahito

    Strong solutions of the non-stationary Navier-Stokes equations under non-linearized slip or leak boundary conditions are investigated. We show that the problems are formulated by a variational inequality of parabolic type, to which uniqueness is established. Using Galerkin's method and deriving a priori estimates, we prove global and local existence for 2D and 3D slip problems respectively. For leak problems, under no-leak assumption at t=0 we prove local existence in 2D and 3D cases. Compatibility conditions for initial states play a significant role in the estimates.

  20. Standard partial molar heat capacities and enthalpies of formation of aqueous aluminate under hydrothermal conditions from integral heat of solution measurements

    International Nuclear Information System (INIS)

    Coulier, Yohann; Tremaine, Peter R.

    2014-01-01

    Highlights: • Heats of solution of NaAlO 2 (s) were measured at five temperatures up to 250 °C. • Standard molar enthalpies of solution were determined from the measured heats of solution. • Standard molar enthalpies of solution were correlated with the density model. • The density model allows us to determine the standard molar heat capacities of reaction. - Abstract: Heats of solution of sodium aluminum oxide, NaAlO 2 (s), were measured in aqueous sodium hydroxide solutions using a Tian–Calvet heat-flow calorimeter (Setaram, Model C80) with high pressure “batch cells” made of hastelloy C-276, at five temperatures from (373.15 to 523.15) K, steam saturation pressure, and concentrations from (0.02 to 0.09) mol · kg −1 . Standard molar enthalpies of solution, Δ soln H ∘ , and relative standard molar enthalpies, [H ∘ (T) − H ∘ (298.15 K)], of NaAl(OH) 4 (aq) were determined from the measured heats of solution. The results were fitted with the “density” model. The temperature dependence of Δ soln H ∘ from the model yielded the standard molar heat capacities of reaction, Δ soln C p ∘ , from which standard partial molar heat capacities for aqueous aluminate, C p ∘ [A1(OH) 4 − ,aq], were calculated. Standard partial molar enthalpies of formation, Δ f H ∘ , and entropies, S ∘ , of A1(OH) 4 − (aq) were also determined. The values for C p ∘ [A1(OH) 4 − ,aq] agree with literature data determined up to T = 413 K from enthalpy of solution and heat capacity measurements to within the combined experimental uncertainties. They are consistent with differential heat capacity measurements up to T = 573 K from Schrödle et al. (2010) [29] using the same calorimeter, but this method has the advantage that measurements could be made at much lower concentrations in the presence of an excess concentration of ligand. To our knowledge, these are the first standard partial molar heat capacities measured under hydrothermal conditions by the

  1. Computational issues of solving the 1D steady gradually varied flow equation

    Directory of Open Access Journals (Sweden)

    Artichowicz Wojciech

    2014-09-01

    Full Text Available In this paper a problem of multiple solutions of steady gradually varied flow equation in the form of the ordinary differential energy equation is discussed from the viewpoint of its numerical solution. Using the Lipschitz theorem dealing with the uniqueness of solution of an initial value problem for the ordinary differential equation it was shown that the steady gradually varied flow equation can have more than one solution. This fact implies that the nonlinear algebraic equation approximating the ordinary differential energy equation, which additionally coincides with the wellknown standard step method usually applied for computing of the flow profile, can have variable number of roots. Consequently, more than one alternative solution corresponding to the same initial condition can be provided. Using this property it is possible to compute the water flow profile passing through the critical stage.

  2. n-Type Conductivity of Cu2O Thin Film Prepared in Basic Aqueous Solution Under Hydrothermal Conditions

    Science.gov (United States)

    Ursu, Daniel; Miclau, Nicolae; Miclau, Marinela

    2018-03-01

    We report for the first time in situ hydrothermal synthesis of n-type Cu2O thin film using strong alkaline solution. The use of copper foil as substrate and precursor material, low synthesis temperature and short reaction time represent the arguments of a new, simple, inexpensive and high field synthesis method for the preparation of n-type Cu2O thin film. The donor concentration of n-type Cu2O thin film obtained at 2 h of reaction time has increased two orders of magnitude than previous reported values. We have demonstrated n-type conduction in Cu2O thin film prepared in strong alkaline solution, in the contradiction with the previous works. Based on experimental results, the synthesis mechanism and the origin of n-type photo-responsive behavior of Cu2O thin film were discussed. We have proposed that the unexpected n-type character could be explained by H doping of Cu2O thin film in during of the hydrothermal synthesis that caused the p-to-n conductivity-type conversion. Also, this work raises new questions about the origin of n-type conduction in Cu2O thin film, the influence of the synthesis method on the nature of the intrinsic defects and the electrical conduction behavior.

  3. Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions. Final report, November 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    A study is described on the hydrological and geotechnical behavior of an oil shale solid waste. The objective was to obtain information which can be used to assess the environmental impacts of oil shale solid waste disposal in the Green River Basin. The spent shale used in this study was combusted by the Lurgi-Ruhrgas process by Rio Blanco Oil Shale Company, Inc. Laboratory bench-scale testing included index properties, such as grain size distribution and Atterberg limits, and tests for engineering properties including hydraulic conductivity and shear strength. Large-scale tests were conducted on model spent shale waste embankments to evaluate hydrological response, including infiltration, runoff, and seepage. Large-scale tests were conducted at a field site in western Colorado and in the Environmental Simulation Laboratory (ESL)at the University of Wyoming. The ESL tests allowed the investigators to control rainfall and temperature, providing information on the hydrological response of spent shale under simulated severe climatic conditions. All experimental methods, materials, facilities, and instrumentation are described in detail, and results are given and discussed. 34 refs.

  4. Exponential stability of switched linear systems with time-varying delay

    Directory of Open Access Journals (Sweden)

    Satiracoo Pairote

    2007-11-01

    Full Text Available We use a Lyapunov-Krasovskii functional approach to establish the exponential stability of linear systems with time-varying delay. Our delay-dependent condition allows to compute simultaneously the two bounds that characterize the exponential stability rate of the solution. A simple procedure for constructing switching rule is also presented.

  5. Global exponential stability of BAM neural networks with time-varying delays and diffusion terms

    International Nuclear Information System (INIS)

    Wan Li; Zhou Qinghua

    2007-01-01

    The stability property of bidirectional associate memory (BAM) neural networks with time-varying delays and diffusion terms are considered. By using the method of variation parameter and inequality technique, the delay-independent sufficient conditions to guarantee the uniqueness and global exponential stability of the equilibrium solution of such networks are established

  6. Global exponential stability of BAM neural networks with time-varying delays and diffusion terms

    Science.gov (United States)

    Wan, Li; Zhou, Qinghua

    2007-11-01

    The stability property of bidirectional associate memory (BAM) neural networks with time-varying delays and diffusion terms are considered. By using the method of variation parameter and inequality technique, the delay-independent sufficient conditions to guarantee the uniqueness and global exponential stability of the equilibrium solution of such networks are established.

  7. Measurement and analysis of polarization curves of mild steel in sodium carbonate/bicarbonate solution under erosion-corrosion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Q. [Taiyuan University of Technology, Taiyuan (China). Research Institute of Surface Engineering

    2002-06-01

    The polarization curves of mild steel in de-aerated 0.5 and mol NaHCO{sub 3} + 0.5 mol Na{sub 2}CO{sub 3} solution with and without erodent particles of 300 g/L of 100 {mu}m alumina have been measured using a rotating cylinder electrode (RCE) apparatus over the range of rotation speeds fro 0 to 4,000 r/min. The results show that the mild steel in the de-aerated slurry exhibits classical active/passive polarization behavior. The speed of cylinder rotation has a great effect in the presence of particles on the active dissolution current density. The erosion-corrosion process is severely erosion-dominated for the mild steel. However, the poor corrosion resistance of the mild steel in such turbulent slurries is also significant, especially at lower than 4 m/s. 19 refs., 5 figs.

  8. Time-varying BRDFs.

    Science.gov (United States)

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

  9. Soil conditions under a Fagus sylvatica CONECOFOR stand in Central Italy: an integrated assessment through combined solid phase and solution studies

    Directory of Open Access Journals (Sweden)

    Guido SANESI

    2002-09-01

    Full Text Available As soil solution represents the major phase of soil chemical reactions, its study is a powerful tool for ecological investigations. Soil solution chemical composition gives a realistic idea about the soil chemical components immediately available in the environment, mainly in relation to the soil ecosystem reaction to the disturbance due to acidifying loads. Within the CONECOFOR Program, the monitoring of forest soil conditions was performed in a level II plot (ABR I, under a Fagus sylvatica (European beech stand, through the study of throughfall and soil solutions collected from depths ranging between the base of the litter layers and 90 cm. To be able to investigate solution contents of nutrients, acidifying agents and DOC throughout the profile, both zero tension and tension lysimeters were used. The first ones were inserted below the organic horizons, while tension lysimeters were placed within the mineral horizons at 15, 25, 55 and 90 cm depth. Sampled solutions were analyzed for Na, K, Ca, Mg, NH4, Cl, F, NO3, SO4, and DOC. The results evidence a clear seasonal pattern, mainly for macronutrients and inorganic N components. Acidic pulses were mostly evident below the organic horizons, in relation to strong nitric N releases from litter; these last were not always immediately neutralized by basic cations. Acid solutions leaving the organic horizons were invariably neutralized in the surface mineral horizons, within 15 cm depth. Temporal patterns of sulphate retention and release suggest that the soil has low retention capability for this anion. Such behaviour can be explained by the composition of the solid phase, where potential anion adsorbants appear strongly linked with organic matter in long residence time complexes. Sulphate and nitrate loading of this soil appear, anyway, to be mostly non-anthropogenic, but rather linked to natural mineralization pulses and, for sulphate, to aeolian solid transport from the south.

  10. Securing the Future of Cultural Heritage by Identifying Barriers to and Strategizing Solutions for Preservation under Changing Climate Conditions

    Directory of Open Access Journals (Sweden)

    Sandra Fatorić

    2017-11-01

    Full Text Available Climate change challenges cultural heritage management and preservation. Understanding the barriers that can impede preservation is of paramount importance, as is developing solutions that facilitate the planning and management of vulnerable cultural resources. Using online survey research, we elicited the opinions of diverse experts across southeastern United States, a region with cultural resources that are particularly vulnerable to flooding and erosion from storms and sea level rise. We asked experts to identify the greatest challenges facing cultural heritage policy and practice from coastal climate change threats, and to identify strategies and information needs to overcome those challenges. Using content analysis, we identified institutional, technical and financial barriers and needs. Findings revealed that the most salient barriers included the lack of processes and preservation guidelines for planning and implementing climate adaptation actions, as well as inadequate funding and limited knowledge about the intersection of climate change and cultural heritage. Experts perceived that principal needs to overcome identified barriers included increased research on climate adaptation strategies and impacts to cultural heritage characteristics from adaptation, as well as collaboration among diverse multi-level actors. This study can be used to set cultural heritage policy and research agendas at local, state, regional and national scales.

  11. On the initial conditions and solutions of the semi-classical Einstein equations in a cosmological scenario

    Energy Technology Data Exchange (ETDEWEB)

    Pinamonti, Nicola [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2010-01-15

    In this paper we discuss the backreaction of a massive quantum scalar field on the curvature, the latter treated as a classical field. Furthermore, we deal with this problem in the realm of cosmological spacetime by analyzing the Einstein equations in a semiclassical fashion. More precisely, we show that, at least on small intervals of time, solutions for this interacting system exist. This result is achieved furnishing an iteration scheme and showing that it converges in the appropriate Banach space. Moreover, we show that the quantum states with good ultraviolet behavior (Hadamard property) used in order to obtain the backreaction will be completely individuated by their form on the initial surface if chosen to be lightlike. On large intervals of time the situation is more complicated but, if the spacetime is expanding, we show that the end limiting point of the evolution does not depend strongly on the quantum state, because, in this limit, the expectation values of the matter fields responsible for the backreaction do not depend on the particular homogeneous Hadamard state at all. Finally, we comment on the interpretation of the semiclassical Einstein equations for this kind of problems. Although the fluctuations of the expectation values of pointlike fields diverge, if the spacetime and the quantum state have a large spatial symmetry and if we consider the smeared fields on regions of large spatial volume, they tend to vanish. Assuming this point of view the semiclassical Einstein equations become more reliable. (orig.)

  12. Concentrated Solutions of Single-Chain Nanoparticles: A Simple Model for Intrinsically Disordered Proteins under Crowding Conditions.

    Science.gov (United States)

    Moreno, Angel J; Lo Verso, Federica; Arbe, Arantxa; Pomposo, José A; Colmenero, Juan

    2016-03-03

    By means of large-scale computer simulations and small-angle neutron scattering (SANS), we investigate solutions of single-chain nanoparticles (SCNPs), covering the whole concentration range from infinite dilution to melt density. The analysis of the conformational properties of the SCNPs reveals that these synthetic nano-objects share basic ingredients with intrinsically disordered proteins (IDPs), as topological polydispersity, generally sparse conformations, and locally compact domains. We investigate the role of the architecture of the SCNPs in their collapse behavior under macromolecular crowding. Unlike in the case of linear macromolecules, which experience the usual transition from self-avoiding to Gaussian random-walk conformations, crowding leads to collapsed conformations of SCNPs resembling those of crumpled globules. This behavior is already found at volume fractions (about 30%) that are characteristic of crowding in cellular environments. The simulation results are confirmed by the SANS experiments. Our results for SCNPs--a model system free of specific interactions--propose a general scenario for the effect of steric crowding on IDPs: collapse from sparse conformations at high dilution to crumpled globular conformations in cell environments.

  13. On the initial conditions and solutions of the semi-classical Einstein equations in a cosmological scenario

    International Nuclear Information System (INIS)

    Pinamonti, Nicola

    2010-01-01

    In this paper we discuss the backreaction of a massive quantum scalar field on the curvature, the latter treated as a classical field. Furthermore, we deal with this problem in the realm of cosmological spacetime by analyzing the Einstein equations in a semiclassical fashion. More precisely, we show that, at least on small intervals of time, solutions for this interacting system exist. This result is achieved furnishing an iteration scheme and showing that it converges in the appropriate Banach space. Moreover, we show that the quantum states with good ultraviolet behavior (Hadamard property) used in order to obtain the backreaction will be completely individuated by their form on the initial surface if chosen to be lightlike. On large intervals of time the situation is more complicated but, if the spacetime is expanding, we show that the end limiting point of the evolution does not depend strongly on the quantum state, because, in this limit, the expectation values of the matter fields responsible for the backreaction do not depend on the particular homogeneous Hadamard state at all. Finally, we comment on the interpretation of the semiclassical Einstein equations for this kind of problems. Although the fluctuations of the expectation values of pointlike fields diverge, if the spacetime and the quantum state have a large spatial symmetry and if we consider the smeared fields on regions of large spatial volume, they tend to vanish. Assuming this point of view the semiclassical Einstein equations become more reliable. (orig.)

  14. Turnkey Heating, Ventilating, and Air Conditioning and Lighting Retrofit Solution Combining Energy Efficiency and Demand Response Benefits

    Energy Technology Data Exchange (ETDEWEB)

    Doebber, Ian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Deru, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Trenbath, Kim [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-04-12

    NREL worked with the Bonneville Power Administration's Technology Innovation Office to demonstrate a turnkey, retrofit technology that combines demand response (DR) and energy efficiency (EE) benefits for HVAC and lighting in retail buildings. As a secondary benefit, we also controlled various plug loads and electric hot water heaters (EHWH). The technology demonstrated was Transformative Wave's eIQ Building Management System (BMS) automatically responding to DR signals. The BMS controlled the HVAC rooftop units (RTU) using the CATALYST retrofit solution also developed by Transformative Wave. The non-HVAC loads were controlled using both hardwired and ZigBee wireless communication. The wireless controllers, manufactured by Autani, were used when the building's electrical layout was too disorganized to leverage less expensive hardwired control. The six demonstration locations are within the Seattle metro area. Based on the assets curtailed by the BMS at each location, we projected the DR resource. We were targeting a 1.7 W/ft2 shed for the summer Day-Ahead events and a 0.7 W/ft2 shed for the winter events. While summarized in Table ES-1, only one summer DR event was conducted at Casino #2.

  15. Corrosion phenomena on alloy 625 in aqueous solutions containing hydrochloric acid and oxygen under subcritical and supercritical conditions

    International Nuclear Information System (INIS)

    Boukis, N.; Kritzer, P.

    1997-01-01

    Supercritical Water Oxidation (SCWO) is a very effective process to destroy hazardous aqueous wastes containing organic contaminants. The main target applications in the USA are the destruction of DOD and DOE wastes such as rocket fuels and explosives, warfare agents and organics present in low level radioactive liquid wastes. Alloy 625 is frequently used as reactor material for Supercritical Water Oxidation (SCWO) applications. This is due to the favorable combination of mechanical properties, corrosion resistance, price and availability. Nevertheless, the corrosion of alloy 625 like the corrosion of other Ni-base alloys during oxidation of hazardous organic waste containing chloride proceeds too fast and is a major problem in SCWO applications. In these experiments high pressure, high-temperature resistant tube reactors made of alloy 625 were used as specimens. They were exposed to SCWO conditions, without organics, at temperatures up to 500 C and pressures up to 37 MPa for up to 150 h. Simultaneously, coupons also made from alloy 625 are exposed inside the test tubes. The most important corrosion problem for alloy 625 is pitting and intercrystalline corrosion at temperatures near the critical temperature, i.e. in the preheater and cooling sections of the test tubes. Under certain conditions, stress corrosion cracking appears and leads to premature failure of the test reactors. The corrosion products were insoluble in supercritical water and formed thick layers in the supercritical part of the reactor. Under these layers only minor corrosion occurred. 33 refs

  16. An open source high-performance solution to extract surface water drainage networks from diverse terrain conditions

    Science.gov (United States)

    Stanislawski, Larry V.; Survila, Kornelijus; Wendel, Jeffrey; Liu, Yan; Buttenfield, Barbara P.

    2018-01-01

    This paper describes a workflow for automating the extraction of elevation-derived stream lines using open source tools with parallel computing support and testing the effectiveness of procedures in various terrain conditions within the conterminous United States. Drainage networks are extracted from the US Geological Survey 1/3 arc-second 3D Elevation Program elevation data having a nominal cell size of 10 m. This research demonstrates the utility of open source tools with parallel computing support for extracting connected drainage network patterns and handling depressions in 30 subbasins distributed across humid, dry, and transitional climate regions and in terrain conditions exhibiting a range of slopes. Special attention is given to low-slope terrain, where network connectivity is preserved by generating synthetic stream channels through lake and waterbody polygons. Conflation analysis compares the extracted streams with a 1:24,000-scale National Hydrography Dataset flowline network and shows that similarities are greatest for second- and higher-order tributaries.

  17. Lever conditioned stimulus-directed autoshaping induced by saccharin-ethanol unconditioned stimulus solution: effects of ethanol concentration and trial spacing.

    Science.gov (United States)

    Tomie, Arthur; Festa, Eugene D; Sparta, Dennis R; Pohorecky, Larissa A

    2003-05-01

    Two experiments were designed to evaluate whether brief access to a saccharin-ethanol solution would function as an effective unconditioned stimulus (US) in Pavlovian-autoshaping procedures. In these experiments, the insertion of a lever conditioned stimulus (CS) was followed by the brief presentation of a sipper tube containing saccharin-ethanol US solution. Experience with this Pavlovian-autoshaping procedure engendered lever CS-directed autoshaping conditioned responses (CRs) in all rats. In Experiment 1, the concentration of ethanol [0%, 2%, 4%, 6%, or 8% (vol./vol.)] in 0.1% saccharin was systematically increased within subjects across autoshaping sessions to evaluate the relation between a rat's drinking and lever pressing. In Experiment 2, the mean intertrial interval (ITI) duration (60, 90, 120 s) was systematically increased within subjects across autoshaping sessions to evaluate the effect of ITI duration on drinking and lever pressing. A pseudoconditioning control group received lever CS randomly with respect to the saccharin-ethanol US solution. In Experiment 1, lever-press autoshaping CRs developed in all rats, and the tendency of a rat to drink an ethanol concentration was predictive of the performance of lever-press autoshaping CRs. In Experiment 2, longer ITIs induced more lever CS-directed responding, and CS-US paired procedures yielded more lever CS-directed responding than that observed in CS-US random procedures. Saccharin-ethanol is an effective US in Pavlovian-autoshaping procedures, inducing more CS-directed responding than in pseudoconditioning controls receiving CS-US random procedures. More lever CS-directed responding was observed when there was more drinking of the saccharin-ethanol US solution (Experiment 1); when the CS and US were paired, rather than random (Experiment 2); and with longer mean ITI durations (Experiment 2). This pattern of results is consistent with the hypothesis that lever CS-directed responding reflects performance

  18. Transport and retention of biochar nanoparticles in a paddy soil under environmentally-relevant solution chemistry conditions.

    Science.gov (United States)

    Chen, Ming; Wang, Dengjun; Yang, Fan; Xu, Xiaoyun; Xu, Nan; Cao, Xinde

    2017-11-01

    Land application of biochar has been increasingly recommended as a powerful strategy for carbon sequestration and soil remediation. However, the biochar particles, especially those in the nanoscale range, may migrate or carry the inherent contaminants along the soil profile, posing a potential risk to the groundwater. This study investigated the transport and retention of wood chip-derived biochar nanoparticles (NPs) in water-saturated columns packed with a paddy soil. The environmentally-relevant soil solution chemistry including ionic strength (0.10-50 mM), electrolyte type (NaCl and CaCl 2 ), and natural organic matter (0-10 mg L -1 humic acid) were tested to elucidate their effects on the biochar NPs transport. Higher mobility of biochar NPs was observed in the soil at lower ionic strengths, with CaCl 2 electrolyte being more effective than NaCl in decreasing biochar NPs transport. The retained biochar NPs in NaCl was re-entrained (∼57.7%) upon lowering transient pore-water ionic strength, indicating that biochar NPs were reversibly retained in the secondary minimum. In contrast, negligible re-entrainment of biochar NPs occurred in CaCl 2 due to the primary minimum and/or particle aggregation. Humic acid increased the mobility of biochar NPs, likely due to enhanced electrosteric repulsive interactions. The transport behaviors of biochar NPs can be well interpreted by a two-site kinetic retention model that assumes reversible retention for one site, and irreversible retention for the other site. Our findings indicated that the transport of wood chip biochar NPs is significant in the paddy soil, highlighting the importance of understanding the mobility of biochar NPs in natural soils for accurately assessing their environmental impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Detection of dynamically varying interaural time differences

    DEFF Research Database (Denmark)

    Kohlrausch, Armin; Le Goff, Nicolas; Breebaart, Jeroen

    2010-01-01

    of fringes surrounding the probe is equal to the addition of the effects of the individual fringes. In this contribution, we present behavioral data for the same experimental condition, called dynamically varying ITD detection, but for a wider range of probe and fringe durations. Probe durations varied...

  20. A numerical solution to define channel heads and hillslope parameters from digital topography of glacially conditioned catchments

    Science.gov (United States)

    Salcher, Bernhard; Baumann, Sebastian; Kober, Florian; Robl, Jörg; Heiniger, Lukas

    2016-04-01

    The analysis of the slope-area relationship in bedrock streams is a common way for discriminating the channel from the hillslope domain and associated landscape processes. Spatial variations of these domains are important indicators of landscape change. In fluvial catchments, this relationship is a function of contributing drainage area, channel slope and the threshold drainage area for fluvial erosion. The resulting pattern is related to climate, tectonic and underlying bedrock. These factors may become secondary in catchments affected by glacial erosion, as it is the case in many mid- to high-latitude mountain belts. The perturbation (i.e. the destruction) of an initial steady state fluvial bedrock morphology (where uplift is balanced by surface lowering rates) will tend to become successively larger if the repeated action of glacial processes exceeds the potential of fluvial readjustment during deglaciated periods. Topographic change is associated with a decrease and fragmentation of the channel network and an extension of the hillslope domain. In case of glacially conditioned catchments discrimination of the two domains remains problematic and a discrimination inconsistent. A definition is therefore highly needed considering that (i) a spatial shift in the domains affect the process and rate of erosion and (ii) topographic classifications of alpine catchments often base on channel and hillslope parameters (i.e.channel or hillslope relief). Here we propose a novel numerical approach to topographically define channel heads from digital topography in glacially conditioned mountain range catchments in order to discriminate the channel from the hillslope domain. We analyzed the topography of the southern European Central Alps, a region which (i) has been glaciated multiple times during the Quaternary, shows (ii) little lithological variations, is (iii) home of very low erodible rocks and is (iv) known as a region were tectonic processes have largely ceased. The

  1. A new technique for the determination of coronal magnetic fields: A fixed mesh solution to Laplace's equation using line-of-sight boundary conditions

    International Nuclear Information System (INIS)

    Adams, J.; Pneuman, G.W.

    1976-01-01

    A new method for computing potential magnetic field configurations in the solar atmosphere is described. A discrete approximation to Laplace's equation is solved in the domain R(Sun) 1 , 0 1 being an arbitrary radial distance from the solar center). The method utilizes the measured line-of-sight magnetic fields directly as the boundary condition at the solar surface and constrains the field to become radial at the outer boundary, R 1 . First the differential equation and boundary conditions are reduced to a set of two-dimensional equations in r, theta by Fourier transforming out the periodic phi dependence. Next each transformed boundary condition is converted to a Dirichlet surface condition. Then each two-dimensional equation with standard Dirichlet-Dirichlet boundary conditions is solved for the Fourier coefficient it determines. Finally, the solution of the original three dimensional equation is obtained through inverse Fourier transformation. The primary numerical tools in this technique are the use of a finite fast Fourier transform technique and also a generalized cyclic reduction algorithm developed at NCAR. Any extraneous monopole component present in the data can be removed if so desired. (Auth.)

  2. Effects of 4:1 carbohydrate/protein solution versus a carbohydrate-alone solution on IL-6, TNF-α, and cortisol during prolonged cycling in hot environmental conditions

    Directory of Open Access Journals (Sweden)

    Cosio-Lima LM

    2012-03-01

    Full Text Available Ludmila M Cosio-Lima, Bhargav Desai, John W Stelzer, Petra B SchulerDepartment of Health, Leisure, and Exercise Science, University of West Florida, Pensacola, FL, USAPurpose: Intense or prolonged exercise and/or heat stress might affect the immune system creating a response similar to trauma or inflammation, resulting in an increase in the susceptibility to viral infections. For example, during prolonged exercise, inflammatory cytokines, such as tumor necrosis factor (TNF-α, interleukin (IL-6, and the stress hormone cortisol are produced and released. Although there have been several studies examining the effects of nutritional supplementation on cytokine release in elite athletes, few studies have investigated the effects of different energy drinks during exercise in adverse environmental conditions. Therefore, the purpose of this study was to compare plasma levels of inflammatory cytokines TNF-α and IL-6, and the stress hormone cortisol, during prolonged cycling under hot environmental conditions while ingesting fluid that contains a ratio of 4:1 carbohydrates and protein (4:1 CHO/PRO versus a carbohydrate-only drink (CHO.Methods: Six male cyclists (aged 27 ± 8 years; weight 75.5 ± 3.4 kg; VO2max = 66 ± 2.7 mL/kg/min, mean ± standard error rode on a stationary ergometer on two separate sessions for 2.5 hours at 75% VO2max in an environmental chamber set at 35°C and 60% relative humidity. During the first session the cyclists were given 4 mL/kg body weight of a 6% carbohydrate solution every 15 minutes. During the second session they were given 4 mL/kg body weight of a 4:1 carbohydrate/protein drink every 15 minutes. Subjects were not aware of which drink they were given in each trial. Blood samples were taken pre-, immediately post-, and 12 hours post-exercise. SPSS (IBM Corp, Armonk, NY was utilized to analyze data through repeated measures analysis of variance.Results: No significant main effect was observed between treatments in

  3. Exact solution for a two-phase Stefan problem with variable latent heat and a convective boundary condition at the fixed face

    Science.gov (United States)

    Bollati, Julieta; Tarzia, Domingo A.

    2018-04-01

    Recently, in Tarzia (Thermal Sci 21A:1-11, 2017) for the classical two-phase Lamé-Clapeyron-Stefan problem an equivalence between the temperature and convective boundary conditions at the fixed face under a certain restriction was obtained. Motivated by this article we study the two-phase Stefan problem for a semi-infinite material with a latent heat defined as a power function of the position and a convective boundary condition at the fixed face. An exact solution is constructed using Kummer functions in case that an inequality for the convective transfer coefficient is satisfied generalizing recent works for the corresponding one-phase free boundary problem. We also consider the limit to our problem when that coefficient goes to infinity obtaining a new free boundary problem, which has been recently studied in Zhou et al. (J Eng Math 2017. https://doi.org/10.1007/s10665-017-9921-y).

  4. Influence of Chemical Composition on Rupture Properties at 1200 Degrees F. of Forged Chromium-Cobalt-Nickel-Iron Base Alloys in Solution-Treated and Aged Condition

    Science.gov (United States)

    Reynolds, E E; Freeman, J W; White, A E

    1951-01-01

    The influence of systematic variations of chemical composition on rupture properties at 1200 degrees F. was determined for 62 modifications of a basic alloy containing 20 percent chromium, 20 percent nickel, 20 percent cobalt, 3 percent molybdenum, 2 percent tungsten, 1 percent columbium, 0.15 percent carbon, 1.7 percent manganese, 0.5 percent silicon, 0.12 percent nitrogen and the balance iron. These modifications included individual variations of each of 10 elements present and simultaneous variations of molybdenum, tungsten, and columbium. Laboratory induction furnace heats were hot-forged to round bar stock, solution-treated at 2200 degrees F., and aged at 1400 degrees F. The melting and fabrication conditions were carefully controlled in order to minimize all variable effects on properties except chemical composition. Information is presented which indicates that melting and hot-working conditions play an important role in high-temperature properties of alloys of the type investigated.

  5. The impact of UV-B and sulphur- or copper-containing solutions in acidic conditions on chlorophyll fluorescence in selected Ramalina species

    International Nuclear Information System (INIS)

    Garty, J.; Tamir, O.; Levin, T.; Lehr, H.

    2007-01-01

    Ramalina maciformis and Ramalina lacera were exposed to different solutions and UV-B to seek for alterations in the PSII photosynthetic quantum yield (F v /F m ), in response to chemicals and radiation. For R. maciformis, significant alterations of the F v /F m ratio occurred only in response to different bisulphite solutions. The F v /F m ratio decreased most in R. maciformis and R. lacera following exposure to 5 and 1 mM bisulphite, respectively. Significant differences in F v /F m ratios were observed for R. lacera in response to different solutions and light at different wavelengths, this being synergistic. The PSII system was unaffected by simulated acid rain in both lichens. R. maciformis, in particular, may survive limited acid rain exposure owing to high Ca oxalate accumulation. The F v /F m ratio decreased most in R. lacera following short-term exposures to CuSO 4 , suggesting that this species is more sensitive to Cu ions under acidic conditions. - Lichens in the eastern Mediterranean tolerate acid rain owing to high Ca content in the thallus, but are sensitive to bisulphite

  6. Photoassisted reduction of metal ions and organic dye by titanium dioxide nanoparticles in aqueous solution under anoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Doong, Ruey-An, E-mail: radoong@mx.nthu.edu.tw [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu, 30013, Taiwan (China); Hsieh, Tien-Chin [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu, 30013, Taiwan (China); Huang, Chin-Pao [Department of Civil and Environmental Engineering, University of Delaware, Newark, 19716, Delaware (United States)

    2010-07-15

    The photoassisted reduction of metal ions and organic dye by metal-deposited Degussa P25 TiO{sub 2} nanoparticles was investigated. Copper and silver ions were selected as the target metal ions to modify the surface properties of TiO{sub 2} and to enhance the photocatalytic activity of TiO{sub 2} towards methylene blue (MB) degradation. X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used to characterize the crystallinity, chemical species and morphology of metal-deposited TiO{sub 2}, respectively. Results showed that the particle size of metal-deposited TiO{sub 2} was larger than that of Degussa P25 TiO{sub 2}. Based on XRPD patterns and XPS spectra, it was observed that the addition of formate promoted the photoreduction of metal ion by lowering its oxidation number, and subsequently enhancing the photodegradation efficiency and rate of MB. The pseudo-first-order rate constant (k{sub obs}) for MB photodegradation by Degussa P25 TiO{sub 2} was 3.94 x 10{sup -2} min{sup -1} and increased by 1.4-1.7 times in k{sub obs} with metal-deposited TiO{sub 2} for MB photodegradation compared to simple Degussa P25 TiO{sub 2}. The increase in mass loading of metal ions significantly enhanced the photodegradation efficiency of MB; the k{sub obs} for MB degradation increased from 3.94 x 10{sup -2} min{sup -1} in the absence of metal ion to 4.64-7.28 x 10{sup -2} min{sup -1} for Ag/TiO{sub 2} and to 5.14-7.61 x 10{sup -2} min{sup -1} for Cu/TiO{sub 2}. In addition, the electrons generated from TiO{sub 2} can effectively reduce metal ions and MB simultaneously under anoxic conditions. However, metal ions and organic dye would compete for electrons from the illuminated TiO{sub 2}.

  7. Mode solutions for a Klein-Gordon field in anti-de Sitter spacetime with dynamical boundary conditions of Wentzell type

    Science.gov (United States)

    Dappiaggi, Claudio; Ferreira, Hugo R. C.; Juárez-Aubry, Benito A.

    2018-04-01

    We study a real, massive Klein-Gordon field in the Poincaré fundamental domain of the (d +1 )-dimensional anti-de Sitter (AdS) spacetime, subject to a particular choice of dynamical boundary conditions of generalized Wentzell type, whereby the boundary data solves a nonhomogeneous, boundary Klein-Gordon equation, with the source term fixed by the normal derivative of the scalar field at the boundary. This naturally defines a field in the conformal boundary of the Poincaré fundamental domain of AdS. We completely solve the equations for the bulk and boundary fields and investigate the existence of bound state solutions, motivated by the analogous problem with Robin boundary conditions, which are recovered as a limiting case. Finally, we argue that both Robin and generalized Wentzell boundary conditions are distinguished in the sense that they are invariant under the action of the isometry group of the AdS conformal boundary, a condition which ensures in addition that the total flux of energy across the boundary vanishes.

  8. Lizimetric investigation of vertical transportation of Cs-137 in the different soil types for the different raining conditions: a new solution proposal and application for the Chernobyl accident

    International Nuclear Information System (INIS)

    Varinlioglu, A.

    2000-12-01

    The aim of this Ph.D. thesis is to trace the vertical transportation of water in soil by using the Cs-137 as radiotracer. We have studied 3 different soil types clay, loamy and sandy and 3 different raining conditions. High, normal and low raining regimes that are typical especially for the Black Sea Region were selected for experimental parameters. These experiments have been realized in lizimetric conditions. As a result, the type of applications for the combinations of soil type and raining regime contain experimental originality. Humidity observation technique was also used. The result of the experiments show that in every raining regime the activities of different types of soils can be classified as sand, loam and clay in descending activity order. When the results of the experiments were evaluated according to the raining regime it can be seen that the relative activity for every type of soil is always towards higher to lower raining conditions. These results are what we already have expected and are related to the water permeability of the soil. The surface soil activities have also been measured. The surface soil activities were arranged as clayey, loamy and sandy in descending activity order for every laining regime. The surface soil activities were found to be higher in the soil types in which water could not penetrate deeper. When the relative activity values were compared with the results of the surface soil activities it was recognized that the order of soils changes upside down. This is an evident of harmony for the experimental results. For the evaluation of surface activity it can be seen that the relative activity values for every kind of soil type is always in the same order from the highest to the lowest raining regimes. As a result, it can be said that the all results have significant and have harmonies with each other. Experimental results were comparatively examined by using the s emi infinite convection dispersion model . All the conclusions

  9. Relación entre la variación de las condiciones ambientales y la temperatura interna de la yema del manzano 'Anna' Inner bud temperature of' Anna' apple trees in relation to varying environmental conditions

    Directory of Open Access Journals (Sweden)

    Casierra Posada Fannor

    2001-12-01

    Full Text Available En Paipa (Colombia, se realizó un ensayo de campo con el fin de determinar el efecto de la variación de las condiciones ambientales sobre la temperatura interna de la yema del manzano 'Anna' cultivado en condiciones de altiplano tropical. Los registros se hicieron en un árbol de cuatro años, el cual se defolió manualmente y se podó pocas semanas después de la cosecha. Se midió la temperatura del aire y se comparó con la temperatura de una yema en el árbol. Para medir la temperatura de la yema se colocó un sensor digital muy delgado entre los catáfilos de la yema; la temperatura ambiente se registró con un termómetro de bulbo. Las mediciones se realizaron cada media hora entre las 7:00 y las 17:30 horas del día, durante 19 días, empezando el día en que el árbol fue defoliado hasta cuando la yema alcanzó el estado fenológico "green tip". Al tiempo con cada medición de temperatura se registró el fenómeno climático más sobresaliente (lluvia, tiempo soleado, viento, tiempo nublado, etc. y los datos se agruparon según cada fenómeno climático. Los resultados mostraron que la yema presentó una temperatura 1,49°C por encima de la temperatura del aire durante el transcurso del día, en la noche no hubo diferencia de temperatura. En condiciones de lluvia, la temperatura
    de la yema estuvo 0,57°C por encima de la temperatura
    del aire. Bajo cielo nublado la yema estuvo 0,56°C más cálida
    que el aire. En condiciones de viento la yema presentó una
    diferencia de 0,87°C sobre la temperatura del aire. En días
    soleados, la yema mantuvo una temperatura 2,3°C sobre la temperatura del aire. Las diferencias entre la temperatura del aire y la de la yema se discuten con base en la transpiración, la convección y la radiación.A field experiment was conducted in Paipa (Colombia to study the effect of environmental varying over inner bud temperature of an 'Anna' apple tree 4 years old growing in tropical

  10. Removal of Cr(VI) from aqueous solutions by a bacterial biofilm supported on zeolite: optimisation of the operational conditions and Scale-Up of the bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Pazos, M. [IBB - Instituto de Biotecnologia e Bioengenharia, Centro de Engenharia Biologica, Universidade do Minho, Braga (Portugal); Departamento de Ingenieria Quimica, Universidade de Vigo, Vigo (Spain); Branco, M.; Tavares, T. [IBB - Instituto de Biotecnologia e Bioengenharia, Centro de Engenharia Biologica, Universidade do Minho, Braga (Portugal); Neves, I.C. [Departamento de Quimica, Centro de Quimica, Universidade do Minho, Braga (Portugal); Sanroman, M.A. [Departamento de Ingenieria Quimica, Universidade de Vigo, Vigo (Spain)

    2010-12-15

    The aim of this study was to investigate the feasibility of a bioreactor system and its scale-up to remove Cr(VI) from solution. The bioreactor is based on an innovative process that combines bioreduction of Cr(VI) to Cr(III) by the bacterium Arthrobacter viscosus and Cr(III) sorption by a specific zeolite. Batch studies were conducted in a laboratory-scale bioreactor, taking into account different operating conditions. Several variables, such as biomass concentration, pH and zeolite pre-treatment, were evaluated to increase removal efficiency. The obtained results suggest that the Cr removal efficiency is improved when the initial biomass concentration is approximately 5 g L{sup -1} and the pH in the system is maintained at an acidic level. Under the optimised conditions, approximately 100 % of the Cr(VI) was removed. The scale-up of the developed biofilm process operating under the optimised conditions was satisfactorily tested in a 150-L bioreactor. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. How fields vary.

    Science.gov (United States)

    Krause, Monika

    2018-03-01

    Field theorists have long insisted that research needs to pay attention to the particular properties of each field studied. But while much field-theoretical research is comparative, either explicitly or implicitly, scholars have only begun to develop the language for describing the dimensions along which fields can be similar to and different from each other. In this context, this paper articulates an agenda for the analysis of variable properties of fields. It discusses variation in the degree but also in the kind of field autonomy. It discusses different dimensions of variation in field structure: fields can be more or less contested, and more or less hierarchical. The structure of symbolic oppositions in a field may take different forms. Lastly, it analyses the dimensions of variation highlighted by research on fields on the sub- and transnational scale. Post-national analysis allows us to ask how fields relate to fields of the same kind on different scales, and how fields relate to fields on the same scale in other national contexts. It allows us to ask about the role resources from other scales play in structuring symbolic oppositions within fields. A more fine-tuned vocabulary for field variation can help us better describe particular fields and it is a precondition for generating hypotheses about the conditions under which we can expect to observe fields with specified characteristics. © London School of Economics and Political Science 2017.

  12. Redox behavior of Tc(VII)/Tc(IV) under various reducing conditions in 0.1 M NaCl solutions

    International Nuclear Information System (INIS)

    Kobayashi, T.; Gaona, X.; Altmaier, M.; Scheinost, A.C.; Fellhauer, D.; European Commission Joint Research Centre, Karlsruhe

    2013-01-01

    Redox behaviour of Tc(VII)/Tc(IV) was investigated in 0.1 M NaCl solutions containing different reducing agents in the pH range 2 to 13 at 22 C under inert Ar atmosphere. In several samples, the 1 x 10 -5 mol/dm 3 (M) initially added TcO 4 - was reduced to form a Tc(IV) oxide solid phase with low solubility. The observed Tc redox transformation processes are systematized according to E h -pH conditions in solution, indicating that a borderline for the reduction of Tc(VII) to Tc(IV), TcO 4 - + 3e - + 4H + TcO 2 . xH 2 O(coll, hyd) + (2-x)H 2 O exists, independent of the reducing chemical system. This experimentally derived borderline is about 100 mV lower than the equilibrium line calculated from the reported standard redox potential of TcO 2 . 1.6H 2 O(s). This behaviour can be related to the existence of more soluble solid phase modifications, i.e. nanoparticulate Tc(IV) oxide species TcO 2 . xH 2 O(coll, hyd). The reaction kinetics likewise correlate to the redox potential measured in solution. Slow reduction of Tc(VII) to Tc(IV) was observed when the redox potential in the system was slightly below the above mentioned reduction borderline. Fast reduction was observed in the systems far below the borderline, but also in those systems containing Fe(II) solids, suggesting a specific surface mediated effect in the reduction process. EXAFS analysis on two magnetite samples indicate reduced Tc(IV) species which do not remain adsorbed at the reactive mineral surface and are incorporated in the magnetite structure. (orig.)

  13. Electrical conductivity of the nutrient solution and plant density in aeroponic production of seed potato under tropical conditions (winter/spring

    Directory of Open Access Journals (Sweden)

    Alex Humberto Calori

    Full Text Available ABSTRACT The recent introduction in Brazil of production of quality seed potatoes in hydroponic systems, such as aeroponics, demands studies on the nutritional and crop management. Thus, this study evaluated the influence of electrical conductivity of the nutrient solution and plant density on the seed potato minitubers production in aeroponics system. The Agata and Asterix cultivars were produced in a greenhouse under tropical conditions (winter/spring. The experimental design was a randomized block in a split-split plot design. The plot consisted of 4 electrical conductivities of the nutrient solution (1.0; 2.0; 3.0; and 4.0 dS∙m−1; the subplot, of 4 plant densities (25; 44; 66; and 100 plants∙m−2; and the subsubplot, of the 2 potato cultivars (Ágata and Asterix, totaling 4 blocks. The 2.2 and 2.1 dS∙m−1 electrical conductivities yielded the highest productivity of seed potato minitubers, for Ágata and Asterix cultivars, respectively, regardless of plant density. For both cultivars, the highest yield was observed for the 100 plants∙m−2 density.

  14. Inverse scattering transform and soliton solutions for square matrix nonlinear Schrödinger equations with non-zero boundary conditions

    Science.gov (United States)

    Prinari, Barbara; Demontis, Francesco; Li, Sitai; Horikis, Theodoros P.

    2018-04-01

    The inverse scattering transform (IST) with non-zero boundary conditions at infinity is developed for an m × m matrix nonlinear Schrödinger-type equation which, in the case m = 2, has been proposed as a model to describe hyperfine spin F = 1 spinor Bose-Einstein condensates with either repulsive interatomic interactions and anti-ferromagnetic spin-exchange interactions (self-defocusing case), or attractive interatomic interactions and ferromagnetic spin-exchange interactions (self-focusing case). The IST for this system was first presented by Ieda et al. (2007) , using a different approach. In our formulation, both the direct and the inverse problems are posed in terms of a suitable uniformization variable which allows to develop the IST on the standard complex plane, instead of a two-sheeted Riemann surface or the cut plane with discontinuities along the cuts. Analyticity of the scattering eigenfunctions and scattering data, symmetries, properties of the discrete spectrum, and asymptotics are derived. The inverse problem is posed as a Riemann-Hilbert problem for the eigenfunctions, and the reconstruction formula of the potential in terms of eigenfunctions and scattering data is provided. In addition, the general behavior of the soliton solutions is analyzed in detail in the 2 × 2 self-focusing case, including some special solutions not previously discussed in the literature.

  15. Application of bacterial leaching technology to deep solution-mining conditions for uranium extraction. Final report, September 1, 1978-September 30, 1981

    International Nuclear Information System (INIS)

    Brierley, J.A.; Brierley, C.L.; Torma, A.E.

    1982-03-01

    Microorganisms were evaluated for use in recovery of uranium under conditions of in-situ solution mining. The cultures tested were Thiobacillus ferrooxidans, the faculative-thermophilic TH3 strain, and two Sulfolobus species. Growth of the organisms occurred in the presence of 0.34 to 5.0 mM uranyl ion with higher concentrations being inhibitory. Uranium ore from the Anaconda Minerals Co. Jackpile mine was not readily leachable by microorganisms. To support bacterial activity the ore was supplemented with pyrite or ferrous iron. The ore possessed some toxic properties. T. ferrooxidans was able to assist in leaching of uranium from the ore at a hydrostatic pressure of 10.3 MPa

  16. Electrochemical studies of the corrosion behavior of a low-carbon steel in aqueous chloride solutions simulating accident conditions of radioactive waste disposal

    International Nuclear Information System (INIS)

    Farvaque-Bera, A.M.; Leistikow, S.

    1991-01-01

    The fine-grained structural steel DIN W.Nr. 1.0566 was exposed to various sulfate and chloride-containing aqueous solutions, the latter ones simulating the potential accidental environment of water intrusion into a salt mine. By electrochemical measurements in salt brines, the following results were achieved: (1) The corrosion rate is highly dependent on salt brine composition, pH and temperature. (2) Active metal dissolution led to formation of shallow pits as surface corrosion phenomenon. Thus, the application of electrochemical techniques - under non-polarized as well as under potentiodynamic conditions - proved to be suitable for fast qualitative testing of the influence of various environmental parameters on steel corrosion. (orig.)

  17. Heterogeneous nucleation promotes carrier transport in solution-processed organic field-effect transistors

    KAUST Repository

    Li, Ruipeng; Khan, Hadayat Ullah; Payne, Marcia M.; Smilgies, Detlef Matthias; Anthony, John Edward; Amassian, Aram

    2012-01-01

    -ray scattering (GIWAXS) in an environmental chamber provides unique quantitative insights into the time-evolution of the concentration of the solution, the onset of nucleation, and the mode of growth of the organic semiconductor under varied drying conditions

  18. Physico-chemical Stability of MabThera Drug-product Solution for Subcutaneous Injection under in-use Conditions with Different Administration Materials.

    Science.gov (United States)

    Mueller, Claudia; Dietel, Elke; Heynen, Severin R; Nalenz, Heiko; Goldbach, Pierre; Mahler, Hanns-Christian; Schmidt, Johannes; Grauschopf, Ulla; Schoenhamnmer, Karin

    2015-01-01

    MabThera is an essential component of the standard-of-care regimens in the treatment of non-Hodgkin lymphoma and Chronic Lymphatic Leukemia. MabThera for subcutaneous injection is a novel line extension that has been approved by the European Medicines Agency for the treatment of patients with follicular lymphoma and diffuse large B-cell lymphoma. This study aimed to evaluate in-use stability data of MabThera subcutaneous drug-product solution in single-use syringes for subcutaneous administration according to the European Medicines Agency guideline. The drug-product solution was exposed to material contact surfaces of five different administration setups commonly used in subcutaneous drug delivery. MabThera subcutaneous was transferred under aseptic conditions into polypropylene and polycarbonate syringes and stored for 1, 2, and 4 weeks at 2°C to 8°C followed by 24 hours at 30°C. After storage, subcutaneous administration was simulated and MabThera subcutaneous drug-product solution quality attributes were evaluated by using compendial physico-chemical tests, as well as suitable and validated molecule- and formulation-specific analytical methods. MabThera subcutaneous vials were treated and analyzed in parallel. The physico-chemical results of MabThera subcutaneous in the different setups were comparable to the control for all timepoints. No change in drug-product quality after storage and simulated administration was found compared to the control. However, since single-dose products do not contain preservatives, microbial contamination and growth needs to be avoided and product sterility needs to be ensured. The results showed that MabThera subcutaneous remains compatible and stable, from a physico-chemical perspective, for up to 4 weeks at 2°C to 8°C followed by 24 hours at 30°C with the contact materials tested in this study. In order to avoid and minimize microbial growth, MabThera subcutaneous should be used immediately after removal from the original

  19. Iterative solution of field problems with a varying physical parameter

    NARCIS (Netherlands)

    Tijhuis, A.G.; Beurden, M.C. van; Zwamborn, A.P.M.

    2003-01-01

    In modern society different trends are recognized in the usage of the available electromagnetic spectrum. One can think of a wireless communication or transport of (digital) information. The density of such applications is increasing rapidly. Obtaining electromagnetic compatibility and/or reducing

  20. Water-base acrylic terpolymer as a corrosion inhibitor for SAE1018 in simulated sour petroleum solution in stagnant and hydrodynamic conditions

    International Nuclear Information System (INIS)

    Vakili Azghandi, M.; Davoodi, A.; Farzi, G.A.; Kosari, A.

    2012-01-01

    Highlights: ► Corrosion inhibition of a water-base copolymer, ATP, was studied. ► Efficiency more than 90% was obtained with 0.8 mmol/L ATP in 2000 rpm. ► ATP obeys Langmuir isotherm in static and hydrodynamic conditions. ► With the presence of ATP, OM images showed a decrease in surface attack. - Abstract: The effect of static and hydrodynamic conditions (0–2000 rpm) on corrosion inhibition of a water-base acrylic terpolymer (ATP), methyl methacrylate/butyl acrylate/acrylic acid, for SAE1018 steel in simulated sour petroleum corrosive solution (NACE 1D196) were investigated by AC/DC electrochemical tests. Increase in rotation speed accelerates the corrosion rate; however the corrosion inhibitor efficiency increases. This was attributed to the enhanced mass transport of inhibitor molecules to the metal surface. OM examinations also demonstrate that in presence of ATP, a decrease in corrosion attacks is observed. Thermodynamic calculations also showed that ATP obeys Langmuir adsorption isotherm and adsorbs chemically into the surface.

  1. Modelling the transition between fixed and mobile bed conditions in two-phase free-surface flows: The Composite Riemann Problem and its numerical solution

    Science.gov (United States)

    Rosatti, Giorgio; Zugliani, Daniel

    2015-03-01

    In a two-phase free-surface flow, the transition from a mobile-bed condition to a fixed-bed one (and vice versa) occurs at a sharp interface across which the relevant system of partial differential equations changes abruptly. This leads to the possibility of conceiving a new type of Riemann Problem (RP), which we have called Composite Riemann Problem (CRP), where not only the initial constant values of the variables but also the system of equations change from left to right of a discontinuity. In this paper, we present a strategy for solving a CRP by reducing it to a standard RP of a single, composite system of equations. This can be obtained by combining the two original systems by means of a suitable weighting function, namely the erodibility variable, and the introduction of an appropriate differential equation for this quantity. In this way, the CRP problem can be analyzed theoretically with standard methods, and the features of the solutions can be clearly identified. In particular, a stationary contact wave is able to correctly describe the sharp transition between mobile- and fixed-bed conditions. A finite volume scheme based on the Multiple Averages Generalized Roe approach (Rosatti and Begnudelli (2013) [22]) was used to numerically solve the fixed-mobile CRP. Several test cases demonstrate the effectiveness, exact well balanceness and high accuracy of the scheme when applied to problems that fall within the physical range of applicability of the relevant mathematical model.

  2. Carbon steel corrosion under anaerobic-aerobic cycling conditions in near-neutral pH saline solutions - Part 1: Long term corrosion behaviour

    International Nuclear Information System (INIS)

    Sherar, B.W.A.; Keech, P.G.; Shoesmith, D.W.

    2011-01-01

    Highlights: → Anaerobic-aerobic cycling on pipeline steel forms two distinct surface morphologies. → Seventy-five percentage of the surface was covered by a black, compact layer ∼4.5 μm thick. → A tubercle, ∼3 to 4 mm in cross section, covered the remaining 25% of surface. → The tubercle cross section showed a single large pit ∼275 μm deep. - Abstract: The influence of anaerobic-aerobic cycling on pipeline steel corrosion was investigated in near-neutral carbonate/sulphate/chloride solution (pH 9) over 238 days. The corrosion rate increased and decreased as exposure conditions were switched between redox conditions. Two distinct corrosion morphologies were observed. The majority of the surface corroded uniformly to produce a black magnetite/maghemite layer approximately 4.5 μm thick. The remaining surface was covered with an orange tubercle, approximately 3-4 mm in cross section. Analysis of the tubercle cross section revealed a single large pit approximately 275 μm deep. Repeated anaerobic-aerobic cycling localized the corrosion process within this tubercle-covered pit.

  3. Towards an improved understanding of hillslope runoff as a supply for groundwater recharge: Assessing hillslope runoff under regional deforestation and varying climate conditions in a drainage basin in central coastal California

    Science.gov (United States)

    Young, K. S.; Beganskas, S.; Fisher, A. T.

    2017-12-01

    We use a hydrologic model to analyze hillslope runoff under a range of climate and land use conditions in the San Lorenzo River Basin (SLRB), central coastal California, including contemporary land use and incremental deforestation. The SLRB is a heavily forested watershed with chronically overdrafted aquifers; in some areas, groundwater levels have been lowered by >50 m in recent decades. Managed aquifer recharge (MAR) can help mitigate declines in groundwater storage, routing excess surface flows to locations where they can infiltrate. We are especially interested in opportunities for collection of stormwater runoff, particularly where development and other changes in landuse have increased hill slope runoff. To assess hillslope runoff at the subwatershed scale (10-100 ha; 25-250 ac), we apply the Precipitation Runoff Modeling System (PRMS) to a high-resolution, digital elevation model and populate the simulation with area- and density-weighted vegetation and soil parameters calculated from high resolution input data. We also develop and apply a catalog of dry, normal, and wet climate scenarios from the historic record (1981-2014). In addition, we simulate conditions ranging from 0 to 100 percent of redwoods harvested (representing the mid-1800s to 1930s logging era) using a historical land use data set to alter soil and vegetation conditions. Results under contemporary land use suggest there are ample opportunities to establish MAR projects during all climate scenarios; hill slope runoff generation is spatially variable and on average exceeds 23,000 ac-ft/yr (3.2 in/yr) during the driest climate scenario. Preliminary results from the deforestation scenarios show notable increases in hillslope runoff with progressive redwood harvesting. Relative to pre-logging conditions, between 1.1 in (dry climates) and 1.5 in (wet climates) more runoff is generated under contemporary conditions, with most of the runoff increase occurring in urban areas. These modeling methods

  4. Productivity of seed agrocenosis of common millet (Panicum miliaceum L. at varying so­ ing w terms and techniques under the conditions of Right- Bank Forest-Steppe

    Directory of Open Access Journals (Sweden)

    С. П. Полторецький

    2013-08-01

    Full Text Available The objective of the research is to improve the techno­logy of growing high-quality seeds of millet broomcorn by means of the optimization of sowing terms and methods, aimed at increasing its productivity and improving seed qualities under conditions of unstable moistening of the Right-Bank Forest-Steppe of Ukraine. Scientific literature review indicates the study of the influence of these technology elements on the formation of sowing qualities and crop capacity of millet seeds has been of schematic and occasional nature. The issue has not been studied in this region condition at all, that is why the research has considerable significance and novelty. Analysis, observations and calculations were done by means of conventional methods. Research results indicate that under conditions of unstable moistening of the southern part of the Right-Bank Forest-Steppe of Ukraine the highest yield of Slobozhanske and Lana varieties was reached at sowing in drills – 39.2 and 41.0 metric centners per hectare, respectively. That was 2.4 and 3.9 metric centners per hectare increase against the wide-row sowing. In the years with optimal hydrothermal conditions maximum seed productivity of millet broomcorn at the level of 4.24 to 4.79 metric tons per hectare (Slobozhanske variety and 4.53 to 5.28 metric tons per hectare (Lana variety was observed at postponing the sowing terms to the third decade of May. If atypical for the region hydrothermal conditions (drought or excessive moistening are forecasted du­ ring the vegetation period of millet, the highest productivity is provided by sowing in the second decade of May. Early sowing in the first decade of May causes decrease in yield at the level of 0.14 to 0.48 metric tons per hectare (Slobozhanske variety and 0.14 to 0.48 metric tons per hectare (Lana variety; if the sowing is postponed to the first decade of June, the yield increases by 0.31 to 0.77 and 0.39 to 0.84 metric tons per hectare, respectively. Early

  5. The isotopic composition of valves and organic tissue of diatoms grown in steady state cultures under varying conditions of temperature, light and nutrients. Implications for the interpretation of oxygen isotopes from sedimentary biogenic opal as proxies of environmental variations

    Energy Technology Data Exchange (ETDEWEB)

    Kowalczyk, K

    2006-05-15

    The oxygen isotopes of diatomaceous silica from marine and freshwater sediments are frequently used as indicators of the palaeotemperature development, particularly in cases where calcareous microfossils are rare or absent. With regard to terrestrial waters it is unknown whether or not palaeotemperature scale can be used in a limnic ecosystem. Due to the fact that the seasonal variations in lakes are larger than in oceans, specific problems arise when working with freshwater sediments. Thus, an understanding of the contribution of the various factors (e.g. temperature, light nutrients, competition) influencing the formation of isotope signals in biogenic opal is a prerequisite for the accurate interpretation of environmental processes. Since it is impossible to examine the influence of a single parameter under natural ecosystem conditions due to permanent changes of the environment, laboratory experiments with single diatom species are needed. Therefore, the aim of this study was to investigate the correlation between the oxygen isotope variations in biogenic opal and different environmental parameters using steady state cultures with diatoms. It should be examined whether or not the different diatom species grown under identical conditions show equal oxygen isotope ratios (species relationship), if variations of the water temperature induce variations of the oxygen isotope ratio (relationship with temperature), variable parameters such as light intensity and nitrate concentration influence the isotope ratio, and if vital effects (e.g. growth rate) lead to variations of the oxygen isotope ratio. (orig.)

  6. The isotopic composition of valves and organic tissue of diatoms grown in steady state cultures under varying conditions of temperature, light and nutrients. Implications for the interpretation of oxygen isotopes from sedimentary biogenic opal as proxies of environmental variations

    International Nuclear Information System (INIS)

    Kowalczyk, K.

    2006-05-01

    The oxygen isotopes of diatomaceous silica from marine and freshwater sediments are frequently used as indicators of the palaeotemperature development, particularly in cases where calcareous microfossils are rare or absent. With regard to terrestrial waters it is unknown whether or not palaeotemperature scale can be used in a limnic ecosystem. Due to the fact that the seasonal variations in lakes are larger than in oceans, specific problems arise when working with freshwater sediments. Thus, an understanding of the contribution of the various factors (e.g. temperature, light nutrients, competition) influencing the formation of isotope signals in biogenic opal is a prerequisite for the accurate interpretation of environmental processes. Since it is impossible to examine the influence of a single parameter under natural ecosystem conditions due to permanent changes of the environment, laboratory experiments with single diatom species are needed. Therefore, the aim of this study was to investigate the correlation between the oxygen isotope variations in biogenic opal and different environmental parameters using steady state cultures with diatoms. It should be examined whether or not the different diatom species grown under identical conditions show equal oxygen isotope ratios (species relationship), if variations of the water temperature induce variations of the oxygen isotope ratio (relationship with temperature), variable parameters such as light intensity and nitrate concentration influence the isotope ratio, and if vital effects (e.g. growth rate) lead to variations of the oxygen isotope ratio. (orig.)

  7. Soil Solution

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    The characteristics of the soil solution in the root environment in the greenhouse industry differ much from those for field grown crops. This is caused firstly by the growing conditions in the greenhouse, which strongly differ from those in the field and secondly the function attributed to the soil

  8. Fluctuation of Dof1/Dof2 expression ratio under the influence of varying nitrogen and light conditions: involvement in differential regulation of nitrogen metabolism in two genotypes of finger millet (Eleusine coracana L.).

    Science.gov (United States)

    Gupta, Supriya; Gupta, Sanjay Mohan; Gupta, Alok Kumar; Gaur, Vikram Singh; Kumar, Anil

    2014-08-10

    In order to gain insights into the mechanism of high nitrogen use efficiency (NUE) of finger millet (FM) the role of Dof2 transcription factor (TF), which is a repressor of genes involved in C/N metabolism was investigated. The partial cDNA fragment of EcDof2 (912-bp; GenBank acc. no. KF261117) was isolated and characterized from finger millet (FM) that showed 63% and 58% homology with Dof2 of Zea mays at nucleotide and protein level, respectively. Its expression studies were carried out along with the activator EcDof1 in two genotypes (GE3885, high protein genotype (HPG); GE1437, low protein genotype (LPG)) of FM differing in grain protein contents (13.8% and 6.2%) showed that EcDof2 is expressed in both shoot and root tissues with significantly (p≤0.05) higher expression in the roots. The diurnal expression of both EcDof1 and EcDof2 in shoots was differential having different time of peak expression indicating a differential response to diurnal condition. Under continuous dark conditions, expression of EcDof1 and EcDof2 oscillated in both the genotypes whereas on illumination, the fold expression of EcDof1 was higher as compared to EcDof2. Under increasing nitrate concentration, EcDof2 expression increases in roots and shoots of LPG while it remains unchanged in HPG. However, the EcDof1 expression was found to increase in both genotypes. Further, time kinetics studies under single nitrate concentration revealed that EcDof2 was repressed in the roots of both genotypes whereas EcDof1 oscillated with time. The EcDof1/EcDof2 ratio measured showed differential response under different light and nitrogen conditions. It was higher in the roots of HPG indicating higher activation of genes involved in N uptake and assimilation resulting in high grain protein accumulation. The results indicate that both light and nitrogen concentration influence Dof1 and Dof2 expression and suggests a complex pattern of regulation of genes influenced by these plant specific TFs. In

  9. Action of a clay suspension on an Fe(0) surface under anoxic conditions: Characterization of neoformed minerals at the Fe(0)/solution and Fe(0)/atmosphere interfaces

    International Nuclear Information System (INIS)

    Le Pape, Pierre; Rivard, Camille; Pelletier, Manuel; Bihannic, Isabelle; Gley, Renaud; Mathieu, Sandrine; Salsi, Lise; Migot, Sylvie; Barres, Odile; Villiéras, Frédéric; Michau, Nicolas

    2015-01-01

    Highlights: • Immersion of an Fe(0) foil in a clay suspension at 90 °C and in anoxic conditions. • Magnetite was observed on the atmospheric part. • Iron-rich 7 Å serpentines were observed on the clay suspension part. • A gradient in serpentine cristallochemistry was observed. • A pure Fe–Si phyllosilicate was identified at the Fe(0)/clay suspension contact. - Abstract: To better understand the reaction mechanisms involved at the Fe(0)/clay minerals interface, we investigate in the present study the reaction between an Fe(0) surface and a clay suspension extracted from the Callovo-Oxfordian claystone (COx). Batch experiments were carried out under anoxic conditions in sealed autoclave, at 90 °C to mimic predicted radioactive waste disposal conditions. An Fe(0) foil was introduced into the autoclave so that the lower part of the foil was immersed in the clay suspension while the upper part was contacted with the atmosphere of the experimental setup. After two months, the mineralogical deposits that precipitated at the surface of the Fe(0) foil were analyzed using multiple techniques, namely X-ray diffraction (XRD), scanning/transmission electron microscopy associated to microanalysis (SEM/TEM–EDXS), and micro-spectroscopic measurements (μ-FTIR and μ-Raman). Both parts of the Fe(0) foil were then shown to react: magnetite was the main resulting mineral formed at the Fe(0) surface in the atmospheric conditions whereas serpentine 1:1 phyllosilicates were the main end-products in the clay suspension. The analyses performed on the immersed part of the foil revealed a spatial heterogeneity in both serpentine cristallochemistry and morphology, with a gradient from the Fe(0) contact point toward the clay suspension. A pure Fe–Si phyllosilicate ring was observed at the direct contact point with the Fe(0) foil and a progressive incorporation of Al instead of Fe into the clay phases was identified as deposit thickness increased from the Fe(0) surface to

  10. Behavior of uranium during the formation of granitic magma by anatexis (I). Influence of redox conditions and the presence of chloride on the solubility of uranium in the hydrothermal solutions

    International Nuclear Information System (INIS)

    Satoru Nakashima; Toshimichi Iiyama, J.

    1983-01-01

    The behavior of uranium is examined experimentally in the course of partial fusion of natural or synthetic granitic rocks. Uranium is definitely soluble in the associated hydrothermal solutions containing chloride under oxidizing conditions, but it is not soluble in the same fluids under reducing conditions [fr

  11. Toxicity and mutagenicity of exhaust from compressed natural gas: Could this be a clean solution for megacities with mixed-traffic conditions?

    Science.gov (United States)

    Agarwal, Avinash K; Ateeq, Bushra; Gupta, Tarun; Singh, Akhilendra P; Pandey, Swaroop K; Sharma, Nikhil; Agarwal, Rashmi A; Gupta, Neeraj K; Sharma, Hemant; Jain, Ayush; Shukla, Pravesh C

    2018-04-20

    Despite intensive research carried out on particulates, correlation between engine-out particulate emissions and adverse health effects is not well understood yet. Particulate emissions hold enormous significance for mega-cities like Delhi that have immense traffic diversity. Entire public transportation system involving taxis, three-wheelers, and buses has been switched from conventional liquid fuels to compressed natural gas (CNG) in the Mega-city of Delhi. In this study, the particulate characterization was carried out on variety of engines including three diesel engines complying with Euro-II, Euro-III and Euro-IV emission norms, one Euro-II gasoline engine and one Euro-IV CNG engine. Physical, chemical and biological characterizations of particulates were performed to assess the particulate toxicity. The mutagenic potential of particulate samples was investigated at different concentrations using two different Salmonella strains, TA98 and TA100 in presence and absence of liver S9 metabolic enzyme fraction. Particulates emitted from diesel and gasoline engines showed higher mutagenicity, while those from CNG engine showed negligible mutagenicity compared to other test fuels and engine configurations. Polycyclic aromatic hydrocarbons (PAHs) adsorbed onto CNG engine particulates were also relatively fewer compared to those from equivalent diesel and gasoline engines. Taken together, our findings indicate that CNG is comparatively safer fuel compared to diesel and gasoline and can offer a cleaner transport energy solution for mega-cities with mixed-traffic conditions, especially in developing countries. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. NUMERICAL AND ANALYTICAL SOLUTIONS OF NEUTRINO-DOMINATED ACCRETION FLOWS WITH A NON-ZERO TORQUE BOUNDARY CONDITION AND ITS APPLICATIONS IN GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wei; Lei, Wei-Hua; Wang, Ding-Xiong, E-mail: leiwh@hust.edu.cn [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-12-20

    A stellar-mass black hole (BH) surrounded by a neutrino-dominated accretion flow (NDAF) has been discussed in a number of works as the central engine of gamma-ray bursts (GRBs). It is widely believed that NDAF cannot liberate enough energy for bright GRBs. However, these works have been based on the assumption of a “no torque” boundary condition, which is invalid when the disk is magnetized. In this paper, we present both numerical and analytical solutions for NDAFs with non-zero boundary stresses and reexamine their properties. We find that an NDAF with such a boundary torque can be powerful enough to account for those bright short GRBs, energetic long GRBs, and ultra-long GRBs. The disk becomes viscously unstable, which makes it possible to interpret the variability of GRB prompt emission and the steep decay phase in the early X-ray afterglow. Finally, we study the gravitational waves radiated from a processing BH-NDAF. We find that the effects of the boundary torque on the strength of the gravitational waves can be ignored.

  13. Optimization of operational conditions in continuous electrodeionization method for maximizing Strontium and Cesium removal from aqueous solutions using artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Zahakifar, Fazel; Keshtkar, Alireza; Nazemi, Ehsan; Zaheri, Adib [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2017-09-01

    Strontium (Sr) and Cesium (Cs) are two important nuclear fission products which are present in the radioactive wastewater resulting from nuclear power plants. They should be treated by considering environmental and economic aspects. In this study, artificial neural network (ANN) was implemented to evaluate the optimal experimental conditions in continuous electrodeionization method in order to achieve the highest removal percentage of Sr and Ce from aqueous solutions. Three control factors at three levels were tested in experiments for Sr and Cs: Feed concentration (10, 50 and 100 mg/L), flow rate (2.5, 3.75 and 5 mL/min) and voltage (5, 7.5 and 10 V). The obtained data from the experiments were used to train two ANNs. The three control factors were utilized as the inputs of ANNs and two quality responses were used as the outputs, separately (each ANN for one quality response). After training the ANNs, 1024 different control factor levels with various quality responses were predicted and finally the optimum control factor levels were obtained. Results demonstrated that the optimum levels of the control factors for maximum removing of Sr (97.6%) had an applied voltage of 10 V, a flow rate of 2.5 mL/min and a feed concentration of 10 mg/L. As for Cs (67.8%) they were 10 V, 2.55 mL/min and 50 mg/L, respectively.

  14. Similarity Solution for Combined Free-Forced Convection Past a Vertical Porous Plate in a Porous Medium with a Convective Surface Boundary Condition

    Directory of Open Access Journals (Sweden)

    Garg P.

    2016-12-01

    Full Text Available This paper studies the mathematical implications of the two dimensional viscous steady laminar combined free-forced convective flow of an incompressible fluid over a semi infinite fixed vertical porous plate embedded in a porous medium. It is assumed that the left surface of the plate is heated by convection from a hot fluid which is at a temperature higher than the temperature of the fluid on the right surface of the vertical plate. To achieve numerical consistency for the problem under consideration, the governing non linear partial differential equations are first transformed into a system of ordinary differential equations using a similarity variable and then solved numerically under conditions admitting similarity solutions. The effects of the physical parameters of both the incompressible fluid and the vertical plate on the dimensionless velocity and temperature profiles are studied and analysed and the results are depicted both graphically and in a tabular form. Finally, algebraic expressions and the numerical values are obtained for the local skin-friction coefficient and the local Nusselt number.

  15. Ellipsometry with randomly varying polarization states

    NARCIS (Netherlands)

    Liu, F.; Lee, C. J.; Chen, J. Q.; E. Louis,; van der Slot, P. J. M.; Boller, K. J.; F. Bijkerk,

    2012-01-01

    We show that, under the right conditions, one can make highly accurate polarization-based measurements without knowing the absolute polarization state of the probing light field. It is shown that light, passed through a randomly varying birefringent material has a well-defined orbit on the Poincar

  16. Solution Prototype

    DEFF Research Database (Denmark)

    Efeoglu, Arkin; Møller, Charles; Serie, Michel

    2013-01-01

    This paper outlines an artifact building and evaluation proposal. Design Science Research (DSR) studies usually consider encapsulated artifact that have relationships with other artifacts. The solution prototype as a composed artifact demands for a more comprehensive consideration in its systematic...... environment. The solution prototype that is composed from blending product and service prototype has particular impacts on the dualism of DSR’s “Build” and “Evaluate”. Since the mix between product and service prototyping can be varied, there is a demand for a more agile and iterative framework. Van de Ven......’s research framework seems to fit this purpose. Van de Ven allows for an iterative research approach to problem solving with flexible starting point. The research activity is the result between the iteration of two dimensions. This framework focuses on the natural evaluation, particularly on ex...

  17. Comparative study of solute trapping and Gibbs free energy changes at the phase interface during alloy solidification under local nonequilibrium conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sobolev, S. L., E-mail: sobolev@icp.ac.ru [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation)

    2017-03-15

    An analytical model has been developed to describe the influence of solute trapping during rapid alloy solidification on the components of the Gibbs free energy change at the phase interface with emphasis on the solute drag energy. For relatively low interface velocity V < V{sub D}, where V{sub D} is the characteristic diffusion velocity, all the components, namely mixing part, local nonequilibrium part, and solute drag, significantly depend on solute diffusion and partitioning. When V ≥ V{sub D}, the local nonequilibrium effects lead to a sharp transition to diffusionless solidification. The transition is accompanied by complete solute trapping and vanishing solute drag energy, i.e. partitionless and “dragless” solidification.

  18. Network Coded Cooperation Over Time-Varying Channels

    DEFF Research Database (Denmark)

    Khamfroush, Hana; Roetter, Daniel Enrique Lucani; Barros, João

    2014-01-01

    transmissions, e.g., in terms of the rate of packet transmission or the energy consumption. A comprehensive analysis of the MDP solution is carried out under different network conditions to extract optimal rules of packet transmission. Inspired by the extracted rules, we propose two near-optimal heuristics......In this paper, we investigate the optimal design of cooperative network-coded strategies for a three-node wireless network with time-varying, half-duplex erasure channels. To this end, we formulate the problem of minimizing the total cost of transmitting M packets from source to two receivers...... as a Markov Decision Process (MDP). The actions of the MDP model include the source and the type of transmission to be used in a given time slot given perfect knowledge of the system state. The cost of packet transmission is defined such that it can incorporate the difference between broadcast and unicast...

  19. Effect of time-varying humidity on the performance of a polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Noorani, Shamsuddin [Department of Mechanical Engineering, University of Michigan-Dearborn (United States); Shamim, Tariq [Mechanical Engineering, Masdar Institute of Science and Technology (United Arab Emirates)], E-mail: tshamim@masdar.ac.ae

    2011-07-01

    In the energy sector, fuel cells constitute a promising solution for the future due to their energy-efficient and environment-friendly characteristics. However, the performance of fuel cells is very much affected by the humidification level of the reactants, particularly in hot regions. The aim of this paper is to develop a better understanding of the effect of driving conditions on the performance of fuel cells. A macroscopic single-fuel-cell-based, one dimensional, isothermal model was used on a polymer electrolyte membrane fuel cell to carry out a computational study of the impact of humidity conditions which vary over time. It was found that the variation of humidity has a significant effect on water distribution but a much lower impact on power and current densities. This paper provided useful information on fuel cells' performance under varying conditions which could be used to improve their design for mobile applications.

  20. Middle Eastern solutions

    International Nuclear Information System (INIS)

    Boersma, M.

    2001-01-01

    The need to consider the Middle East as a group of distinct countries and not as one single market and to tailor the services offered by companies is stressed. The cultures, political and social conditions, forms of the oil and gas industry in the countries making up the Middle East and their technology requirements are different and vary widely. The approach taken by Shell Global Solutions to these differences is described and illustrated with Shell's experiences in Oman and Saudi Arabia. Shell has found that Omanis are keen to work in their oil and gas industry, and to protect their country's natural environment. Saudi also have intense pride in their oil industry and here Shell supports refinery operators reduce costs while maintaining strict quality control. Shell has been selected to help Saudi Arabia develop its natural gas reserves; as part of the Core Venture 3 project, Shell will build a power desalination plant

  1. Scattering of a TEM wave from a time varying surface

    Science.gov (United States)

    Elcrat, Alan R.; Harder, T. Mark; Stonebraker, John T.

    1990-03-01

    A solution is given for reflection of a plane wave with TEM polarization from a planar surface with time varying properties. These properties are given in terms of the currents on the surface. The solution is obtained by numerically solving a system of differential-delay equations in the time domain.

  2. Condition varies with habitat choice in postbreeding forest birds

    Science.gov (United States)

    Scott H. Stoleson

    2013-01-01

    Many birds that are experiencing population declines require extensive tracts of mature forest habitat for breeding. Recent work suggests that at least some may shift their habitat use to early-successional areas after nesting but before migration. I used constant-effort mist netting in regenerating clearcuts (4-8 years postcut) and dense mature-forest understories to...

  3. Spectroscopy on metal-halide lamps under varying gravity conditions

    NARCIS (Netherlands)

    Flikweert, A.J.

    2008-01-01

    Worldwide, 20% of all electricity is used for lighting. For this reason, efficient lamps are economically and ecologically important. High intensity discharge (HID) lamps are efficient lamps. The most common HID lamp these days is the metal-halide (MH) lamp. MH lamps have a good colour rendering

  4. Varying Conditions for Hexanoic Acid Degradation with BioTiger™

    Energy Technology Data Exchange (ETDEWEB)

    Foreman, Koji [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Milliken, Charles [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brigmon, Robin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    BioTiger™ (BT) is a consortium of 12 bacteria designed for petroleum waste biodegradation. BT is currently being studied and could be considered for bioremediation of the Athabasca oil sands refineries in Canada and elsewhere. The run-off ponds from the petroleum extraction processes, called tailings ponds, are a mixture of polycyclic aromatic hydrocarbons, naphthenic acids, hydrocarbons, toxic chemicals like heavy metals, water, and sand. Due to environmental regulations the oil industry would like to separate and degrade the hazardous chemical species from the tailings ponds while recycling the water. It has been shown that BT at 30 C° is able to completely degrade 10 mM hexanoic acid (HA) co-metabolically with 0.2% yeast extract (w/v) in 48 hours when starting at 0.4 OD 600nm. After establishing this stable degradation capability, variations were tested to explore the wider parameters of BT activity in temperature, pH, intermediate degradation, co-metabolic dependence, and transfer stability. Due to the vast differences in temperature at various points in the refineries, a wide range of temperatures were assessed. The results indicate that BT retains the ability to degrade HA, a model surrogate for tailings pond contaminants, at temperatures ranging from 15°C to 35°C. Hexanamide (HAM) was shown to be an intermediate generated during the degradation of HA in an earlier work and HAM is completely degraded after 48 hours, indicating that HAM is not the final product of HA degradation. Various replacements for yeast extract were attempted. Glucose, a carbon source; casein amino acids, a protein source; additional ammonia, mimicking known media; and additional phosphate with Wolffe’s vitamins and minerals all showed no significant degradation of HA compared to control. Decreasing the yeast extract concentration (0.05%) demonstrated limited but significant degradation. Finally, serial inoculations of BT were performed to determine the stability of degradation over several generations. Overall, BT has shown to be moderately flexible for HA co-metabolic biodegradation.

  5. Oscillatory solutions of the Cauchy problem for linear differential equations

    Directory of Open Access Journals (Sweden)

    Gro Hovhannisyan

    2015-06-01

    Full Text Available We consider the Cauchy problem for second and third order linear differential equations with constant complex coefficients. We describe necessary and sufficient conditions on the data for the existence of oscillatory solutions. It is known that in the case of real coefficients the oscillatory behavior of solutions does not depend on initial values, but we show that this is no longer true in the complex case: hence in practice it is possible to control oscillatory behavior by varying the initial conditions. Our Proofs are based on asymptotic analysis of the zeros of solutions, represented as linear combinations of exponential functions.

  6. Time varying, multivariate volume data reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, James P [Los Alamos National Laboratory; Fout, Nathaniel [UC DAVIS; Ma, Kwan - Liu [UC DAVIS

    2010-01-01

    Large-scale supercomputing is revolutionizing the way science is conducted. A growing challenge, however, is understanding the massive quantities of data produced by large-scale simulations. The data, typically time-varying, multivariate, and volumetric, can occupy from hundreds of gigabytes to several terabytes of storage space. Transferring and processing volume data of such sizes is prohibitively expensive and resource intensive. Although it may not be possible to entirely alleviate these problems, data compression should be considered as part of a viable solution, especially when the primary means of data analysis is volume rendering. In this paper we present our study of multivariate compression, which exploits correlations among related variables, for volume rendering. Two configurations for multidimensional compression based on vector quantization are examined. We emphasize quality reconstruction and interactive rendering, which leads us to a solution using graphics hardware to perform on-the-fly decompression during rendering. In this paper we present a solution which addresses the need for data reduction in large supercomputing environments where data resulting from simulations occupies tremendous amounts of storage. Our solution employs a lossy encoding scheme to acrueve data reduction with several options in terms of rate-distortion behavior. We focus on encoding of multiple variables together, with optional compression in space and time. The compressed volumes can be rendered directly with commodity graphics cards at interactive frame rates and rendering quality similar to that of static volume renderers. Compression results using a multivariate time-varying data set indicate that encoding multiple variables results in acceptable performance in the case of spatial and temporal encoding as compared to independent compression of variables. The relative performance of spatial vs. temporal compression is data dependent, although temporal compression has the

  7. Studies on the radiation chemistry of biomolecules in aqueous solution with specific objective of minimizing their radiolytic degradation. Coordinated programme for Asia and the Pacific Region on radiation sterilization practices significant to local medical supplies and conditions

    International Nuclear Information System (INIS)

    Narayana Rao, K.

    1979-01-01

    As part of a study of radiolytic degradation of pharmaceuticals during radiosterilization, the basic radiation chemistry of the B-group vitamins, nicotinamide, pyridoxin, riboflavin and thiamine, and the reaction of hydrogen peroxide with these same materials has been investigated. The various aspects studied were - radiolysis under controlled conditions, effects of phase, temperature, pH and nature and concentration of additives. Some of the conclusions are: 1) with oxygen saturated aqueous solutions containing glucose, the radiolytic degradation of the vitamins is reduced: 2) results a similar for N 2 O saturated aqueous solutions; 3) in glucose-containing solutions, the protective effect is considerably modified at higher temperatures; and 4) irradiation of air-saturated aqueous solutions in the frozen state leads to reduced decomposition. It is concluded that in the presence of oxygen, in frozen matrices at low temperature, it appears possible to reduce the radiolytic breakdown of vitamins to low levels

  8. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly on re...

  9. Eestlased Karlovy Varys / J. R.

    Index Scriptorium Estoniae

    J. R.

    2007-01-01

    Ilmar Raagi mängufilm "Klass" osaleb 42. Karlovy Vary rahvusvahelise filmifestivali võistlusprogrammis "East of the West" ja Asko Kase lühimängufilm "Zen läbi prügi" on valitud festivali kõrvalprogrammi "Forum of Independents"

  10. Esmaklassiline Karlovy Vary / Jaanus Noormets

    Index Scriptorium Estoniae

    Noormets, Jaanus

    2007-01-01

    Ilmar Raagi mängufilm "Klass" võitis 42. Karlovy Vary rahvusvahelise filmifestivalil kaks auhinda - ametliku kõrvalvõistlusprogrammi "East of the West" eripreemia "Special mention" ja Euroopa väärtfilmikinode keti Europa Cinemas preemia. Ka Asko Kase lühifilmi "Zen läbi prügi linastumisest ning teistest auhinnasaajatest ning osalejatest

  11. Optimistlik Karlovy Vary / Jaan Ruus

    Index Scriptorium Estoniae

    Ruus, Jaan, 1938-2017

    2007-01-01

    42. Karlovy Vary rahvusvahelise filmifestivali auhinnatud filmidest (žürii esimees Peter Bart). Kristallgloobuse sai Islandi-Saksamaa "Katseklaasilinn" (režii Baltasar Kormakur), parimaks režissööriks tunnistati norralane Bard Breien ("Negatiivse mõtlemise kunst"). Austraallase Michael James Rowlandi "Hea õnne teekond" sai žürii eripreemia

  12. Spatially varying dispersion to model breakthrough curves.

    Science.gov (United States)

    Li, Guangquan

    2011-01-01

    Often the water flowing in a karst conduit is a combination of contaminated water entering at a sinkhole and cleaner water released from the limestone matrix. Transport processes in the conduit are controlled by advection, mixing (dilution and dispersion), and retention-release. In this article, a karst transport model considering advection, spatially varying dispersion, and dilution (from matrix seepage) is developed. Two approximate Green's functions are obtained using transformation of variables, respectively, for the initial-value problem and for the boundary-value problem. A numerical example illustrates that mixing associated with strong spatially varying conduit dispersion can cause strong skewness and long tailing in spring breakthrough curves. Comparison of the predicted breakthrough curve against that measured from a dye-tracing experiment between Ames Sink and Indian Spring, Northwest Florida, shows that the conduit dispersivity can be as large as 400 m. Such a large number is believed to imply strong solute interaction between the conduit and the matrix and/or multiple flow paths in a conduit network. It is concluded that Taylor dispersion is not dominant in transport in a karst conduit, and the complicated retention-release process between mobile- and immobile waters may be described by strong spatially varying conduit dispersion. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  13. Robust stabilisation of time-varying delay systems with probabilistic uncertainties

    Science.gov (United States)

    Jiang, Ning; Xiong, Junlin; Lam, James

    2016-09-01

    For robust stabilisation of time-varying delay systems, only sufficient conditions are available to date. A natural question is as follows: if the existing sufficient conditions are not satisfied, and hence no controllers can be found, what can one do to improve the stability performance of time-varying delay systems? This question is addressed in this paper when there is a probabilistic structure on the parameter uncertainty set. A randomised algorithm is proposed to design a state-feedback controller, which stabilises the system over the uncertainty domain in a probabilistic sense. The capability of the designed controller is quantified by the probability of stability of the resulting closed-loop system. The accuracy of the solution obtained from the randomised algorithm is also analysed. Finally, numerical examples are used to illustrate the effectiveness and advantages of the developed controller design approach.

  14. A Fully Analytical Solution of the Wellbore Stability Problem under Undrained Conditions Using a Linearised Cam-Clay Model Solution analytique au problème de stabilité de puits en conditions non drainées utilisant un modèle de Cam-Clay linéarisé

    Directory of Open Access Journals (Sweden)

    Charlez P. A.

    2006-12-01

    Full Text Available This paper presents a linearised version of the Cam-Clay model fully integrated in the scope of the general theory of poroplasticity. The constitutive law which is developed in the scope of the effective plastic stress concept, only contains two plastic parameters (hardening modulus and slope of the critical state line. To be validated, the model is integrated over homogeneous stress paths (hydrostatic, drained triaxial and undrained triaxal then compared with experimental data issued from conventional laboratory triaxial tests. In the second part, a simplified version of the model is applied to the wellbore boundary problem (vertical well in an axisymmetric horizontal stress field and under undrained conditions. Given the linearity of the constitutive law and the a priori knowledge of the shape of the plastic region, the solution (stress, strain and pore pressure is fully analytical. The solution shows that for an overconsolidated material (overconsolidation degree less than 2 the hoop stress is strongly relaxed in the plastic zone. The higher the compressibility of the saturating fluid, the larger the relaxation of the hoop stress. In terms of stability, the more compressible the fluid saturating the porous medium is, the more stable the well will be. Finally the larger the overconsolidation ratio is, the less stable the well will be. Cet article présente une version linéarisée du modèle de Cam-Clay intégré dans le cadre général de la théorie de la poroplasticité isotherme. La loi de comportement développée à partir du concept des contraintes effectives plastiques ne contient que deux paramètres plastiques (module d'écrouissage et pente de la droite critique. Le modèle est validé sur des chemins de contrainte homogènes (hydrostatique, triaxial drainé et triaxial non drainé et comparé à des essais expérimentaux obtenus à partir d'essais conventionnels de laboratoire. Ensuite, une version simplifiée du modèle est

  15. Genetic polymorphisms in varied environments.

    Science.gov (United States)

    Powell, J R

    1971-12-03

    Thirteen experimenital populationis of Drosophila willistoni were maintained in cages, in some of which the environments were relatively constant and in others varied. After 45 weeks, the populations were assayed by gel electrophoresis for polymorphisms at 22 protein loci. The average heterozygosity per individual and the average unmber of alleles per locus were higher in populations maintained in heterogeneous environments than in populations in more constant enviroments.

  16. The Thermal Collector With Varied Glass Covers

    International Nuclear Information System (INIS)

    Luminosu, I.; Pop, N.

    2010-01-01

    The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

  17. The Pd-catalyzed hydrodechlorination of chlorophenols in aqueous solutions under mild conditions: A promising approach to practical use in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Xia Chuanhai, E-mail: chuanhaixia@gmail.com [Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003 (China); Liu Ying; Zhou Shiwei; Yang Cuiyun; Liu Sujing [Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003 (China); Xu Jie [Dalian Institute of Chemical Physics, CAS, Dalian, 116021 (China); Yu Junbao [Yantai Institute of Coastal Zone Research for Sustainable Development, CAS, Yantai 264003 (China); Chen Jiping; Liang Xinmiao [Dalian Institute of Chemical Physics, CAS, Dalian, 116021 (China)

    2009-09-30

    Catalytic hydrotreating of chlorophenols was carried out in water with Pd/C at 25 deg. C under atmospheric pressure. 1.0% (w/w) monocholophenols was completely dechlorinated within 60 min. Phenol, cyclohexanone and cyclohexanol were formed. In contrast to the dechlorination of monochlorophenols, the hydrogenation reaction of polychlorinated phenols became difficult and reaction rates were strongly dependent upon the number of the chlorine atoms. The solvent property had a considerably important influence on the dechlorination reaction. Water as a solvent showed more advantages than organic solvents. It was much easier to be hydrodechlorinated for chlorophenols in aqueous solutions. However, the presence of THF, dioxane, DMSO or DMF in water was disadvantageous to the reaction and easily to cause Pd/C deactivation. Additionally, when different halogenated organic compounds were present in aqueous solution, the dehalogenation reaction was the competitive hydrogenation process.

  18. The Pd-catalyzed hydrodechlorination of chlorophenols in aqueous solutions under mild conditions: A promising approach to practical use in wastewater

    International Nuclear Information System (INIS)

    Xia Chuanhai; Liu Ying; Zhou Shiwei; Yang Cuiyun; Liu Sujing; Xu Jie; Yu Junbao; Chen Jiping; Liang Xinmiao

    2009-01-01

    Catalytic hydrotreating of chlorophenols was carried out in water with Pd/C at 25 deg. C under atmospheric pressure. 1.0% (w/w) monocholophenols was completely dechlorinated within 60 min. Phenol, cyclohexanone and cyclohexanol were formed. In contrast to the dechlorination of monochlorophenols, the hydrogenation reaction of polychlorinated phenols became difficult and reaction rates were strongly dependent upon the number of the chlorine atoms. The solvent property had a considerably important influence on the dechlorination reaction. Water as a solvent showed more advantages than organic solvents. It was much easier to be hydrodechlorinated for chlorophenols in aqueous solutions. However, the presence of THF, dioxane, DMSO or DMF in water was disadvantageous to the reaction and easily to cause Pd/C deactivation. Additionally, when different halogenated organic compounds were present in aqueous solution, the dehalogenation reaction was the competitive hydrogenation process.

  19. Influence of moisture conditions and mineralization of soil solution on structure of litter macrofauna of the deciduous forests of Ukraine steppe zone

    Directory of Open Access Journals (Sweden)

    V. V. Brygadyrenko

    2015-02-01

    Full Text Available The accounting of litter mesofauna was carried out in the territory of Dnipropetrovsk, Zaporizhzhya, Nikolaev,Donetsk regions of Ukrainein the natural forest ecosystems in 2001–2014. 339 forest ecosystems were surveyed; xeromesophilic conditions of moistening were characteristic for 47 trial sites, mesophilic conditions – for 99 sites, hygro-mesophilic conditions – for 50 sites, meso-hygrophilic conditions – for 89 sites, hygrophilic conditions – for 54 sites; trophotope C was represented by 35 trial sites, Dc – by 44, Dac – by 76, Dn – by 128, De – by 37, E – by 19 forest ecosystems, accordingly. The relative number of saprophages reaches maximum values in hygro-mesophilic, meso-hygrophilic and hygrophilic conditions, and minimum values – in mesophilic conditions of moistening. The share of rare species is maximum in hygro-mesophilic conditions of moistening. The minimum quantity of mass species is also observed in conditions of hygro-mesophilic and meso-hygrophilic deciduous forests. With the growth of moistening of the soil, quantity of species of Carabidae, Formicidae and other dominant families remains without significant changes. The relative number of Formicidae is maximum in xeromesophilic and mesophilic conditions of soil moistening. In these hygrotopes, as well as in hygro-mesophilic conditions of moistening the Julidae numbers are maximum. The Isopoda percent in mesofauna significantly grows in meso-hygrophilic and hygrophilic conditions of moistening. The share of other dominant taxonomical groups in the structure of litter mesofauna remains without significant changes in numbers. In the majority of the analysed hygrotopes 7–8 families are withing the structure of dominants. In the conditions of salinization (trophotopes De and E, and also on light sandy loam soils, the numbers of litter mesofauna decrease. Share of saprophages is minimum in trophotopes Dc and E, while it increases in trophotopes C, Dac, Dn

  20. Partitioning of the rare earths and actinides between R7T7 nuclear glass alteration products and solution according to disposal conditions

    International Nuclear Information System (INIS)

    Menard, O.

    1995-01-01

    The alteration of nuclear glass by water is liable to release radionuclides into the environment. Determining the release kinetics of these elements and their aqueous chemical forms are therefore essential steps in establishing the safety of a geological repository site. Leach tests were conducted with a nonradioactive specimen of the French ''R7T7'' light water containment glass spiked with U and Th, and with two R7T7 specimens spiked with 237 Np and 239 Pu, respectively. The alteration solution compositions were representative of deep groundwater and contained carbonate, sulfate, phosphate, fluorine and chlorine ions. The release of U, Th, Np and Pu, as well as of the rare earths La, Ce and Nd were monitored by ICP mass spectrometry and by α spectrometry. Scanning and transmission electron microscopic examination of the nonradioactive altered glass surfaces was also performed to assess the partitioning balance for the rare earths, U and Th between the glass alteration products and solution. The mobility of these elements depends on two competing mechanisms. The rare earths and thorium are incorporated in the alteration products (gel); the retention process is assumed to involve chemisorption or coprecipitation, enhanced in the gel layer by the presence of phosphate ions in particular. Conversely, the aqueous species in the alteration solutions (mainly anions) form complexes with the actinides and rare earths; this phenomenon is particularly evident with U and Np. The presence of carbonate ions favors this mobility. Plutonium differs from U and Np in that it is adsorbed mainly on colloids formed by glass dissolution, the principal factors governing its chemical evolution in solution. (author). refs., 122 figs., 185 tabs

  1. Retention prediction of highly polar ionizable solutes under gradient conditions on a mixed-mode reversed-phase and weak anion-exchange stationary phase.

    Science.gov (United States)

    Balkatzopoulou, P; Fasoula, S; Gika, H; Nikitas, P; Pappa-Louisi, A

    2015-05-29

    In the present work the retention of three highly polar and ionizable solutes - uric acid, nicotinic acid and ascorbic acid - was investigated on a mixed-mode reversed-phase and weak anion-exchange (RP/WAX) stationary phase in buffered aqueous acetonitrile (ACN) mobile phases. A U-shaped retention behavior was observed for all solutes with respect to the eluent organic modifier content studied in a range of 5-95% (v/v). This retention behavior clearly demonstrates the presence of a HILIC-type retention mechanism at ACN-rich hydro-organic eluents and an RP-like retention at aqueous-rich hydro-organic eluents. Hence, this column should be promising for application under both RP and HILIC gradient elution modes. For this reason, a series of programmed elution runs were carried out with increasing (RP) and decreasing (HILIC) organic solvent concentration in the mobile phase. This dual gradient process was successfully modeled by two retention models exhibiting a quadratic or a cubic dependence of the logarithm of the solute retention factor (lnk) upon the organic modifier volume fraction (φ). It was found that both models produced by gradient retention data allow the prediction of solute retention times for both types of programmed elution on the mixed-mode column. Four, in the case of the quadratic model, or five, in the case of the cubic model, initial HILIC- and RP-type gradient runs gave satisfactory retention predictions of any similar kind elution program, even with different flow rate, with an overall error of only 2.5 or 1.7%, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Connecting the dots: Semi-analytical and random walk numerical solutions of the diffusion–reaction equation with stochastic initial conditions

    Energy Technology Data Exchange (ETDEWEB)

    Paster, Amir, E-mail: paster@tau.ac.il [Environmental Fluid Mechanics Laboratories, Dept. of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN (United States); School of Mechanical Engineering, Tel Aviv University, Tel Aviv, 69978 (Israel); Bolster, Diogo [Environmental Fluid Mechanics Laboratories, Dept. of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN (United States); Benson, David A. [Hydrologic Science and Engineering, Colorado School of Mines, Golden, CO, 80401 (United States)

    2014-04-15

    We study a system with bimolecular irreversible kinetic reaction A+B→∅ where the underlying transport of reactants is governed by diffusion, and the local reaction term is given by the law of mass action. We consider the case where the initial concentrations are given in terms of an average and a white noise perturbation. Our goal is to solve the diffusion–reaction equation which governs the system, and we tackle it with both analytical and numerical approaches. To obtain an analytical solution, we develop the equations of moments and solve them approximately. To obtain a numerical solution, we develop a grid-less Monte Carlo particle tracking approach, where diffusion is modeled by a random walk of the particles, and reaction is modeled by annihilation of particles. The probability of annihilation is derived analytically from the particles' co-location probability. We rigorously derive the relationship between the initial number of particles in the system and the amplitude of white noise represented by that number. This enables us to compare the particle simulations and the approximate analytical solution and offer an explanation of the late time discrepancies. - Graphical abstract:.

  3. Rolls-Royce I and C long term support a dedicated solution to manage plant condition, optimize operating life and maximize plant value while improving safety

    International Nuclear Information System (INIS)

    Baillonmartos, F.

    2010-01-01

    Rolls-Royce supplied safety I and C equipment as Original Equipment Manufacturer (OEM) for 200 reactors in operation from 1970', including various technological steps (analog to digital hardware). The hardware scope covers various systems, either more than 500 hardware references, either more than 150000 parts in operation. Rolls-Royce contributes to life time extension ensuring system availability and reliability on long term basis by determining the optimum solution between different maintenance approaches: maintenance and repair with limited retrofit or major system retrofit. Based on Long Term Support (LTS) agreement with customers, Rolls-Royce commits to maintain the capability to manufacture, modify, repair, test, at board, rack and systems level over a long time period. This means finding solution to hardware ageing, technology evolution, skills and tools maintenance. This paper describes how Rolls-Royce has built a global process based on delivering a package of services and developing long term support engineering solutions and tools. Our main experience on EDF partnership will serve to illustrate Rolls-Royce I and C Long Term Support activity. (authors)

  4. Experimental study and thermodynamic modelling of methane clathrate hydrate dissociation conditions in silica gel porous media in the presence of methanol aqueous solution

    International Nuclear Information System (INIS)

    Hashemi, Hamed; Javanmardi, Jafar; Zarifi, Mojdeh; Eslamimanesh, Ali; Mohammadi, Amir H.

    2012-01-01

    Highlights: ► Phase equilibria of hydrates of methane in confined silica gel pores are reported. ► Dissociation data in the presences of methanol aqueous solution are also measured. ► A thermodynamic model is developed for prediction of the obtained data. ► Acceptable agreement is found between the obtained data and the predicted results. - Abstract: In this work, the phase equilibria of clathrate hydrates of methane in the presence of pure water and 0.035 mass fraction of methanol aqueous solution in confined silica gel pores with (10 and 15) nm mean diameters are measured and reported. A thermodynamic model is also developed for prediction of the obtained experimental hydrate dissociation data. The Valderrama–Patel–Teja (VPT-EoS) equation of state (EoS) accompanied with the non-density dependent (NDD) mixing rules coupled with a previously developed activity model are applied to evaluate the fugacity of the species present and the activity coefficient of water in methanol aqueous solution. Acceptable agreement between the reported data and the predicted results using the proposed model and an existing method reported in the literature demonstrates the reliability of the presented model.

  5. Suppression of Powdery Mildew Using the Water Extract of Xylogone ganodermophthora and Aqueous Potassium Phosphonate Solution on Watermelon under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Hyo-Jung Kang

    2015-12-01

    Full Text Available Xylogone ganodermophthora (Xg is an ascomycetous fungus that causes yellow rot on cultivated Ganoderma lucidum. Previously, we reported in vitro antifungal activities of a Xg culture extract against several watermelon pathogens. In 2014, we conducted greenhouse experiments to evaluate the control efficacy of a water extract of cultured Xg on watermelon powdery mildew (WPM. The test material (stock solution, ca. 4,000 µg/ml was prepared by an autoclaved Xg culture in water at a ratio of 800 g of culture per 6 liter of water, and then filtering it through filter paper. Six foliar applications of the solutions (diluted 100- and 1,000-fold significantly suppressed the formation of conidiophores and conidia. The inhibitory effect of aqueous potassium phosphonate solution on the disease and its phytotoxicity was tested. Phytotoxicity on watermelon plants was observed at concentrations of 1,000 and 2,000 µg/ml as irregular brownish spots. The control efficacies against WPM were 91.9% at 2,000 µg/ml, 64.9% at 1,000 µg/ml, and 62.2% at 500 µg/ml.

  6. Thermal boundary condition effects on forced convection heat transfer. Application of a numerical solution of an adjoint problem; Kyosei tairyu netsudentatsu mondai ni okeru netsuteki kyokai joken no eikyo. Zuihan mondai no suchi kai wo mochiita kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Momose, K.; Saso, K.; Kimoto, H. [Osaka University, Osaka (Japan). Faculty of Engineering Science

    1997-11-25

    We propose a numerical solution for the adjoint operator of a forced convection heat transfer problem to evaluate mean heat transfer characteristics under arbitrary thermal conditions. Using the numerical solutions of the adjoint problems under Dirichlet and Neumann conditions, both of which can be computed using a conventional CFD code, the influence function of the local surface temperature on the total heat transfer and that of the local surface heat flux on the mean surface temperature are obtained. As a result, the total heat fluxes for arbitrary surface temperature distributions and the mean surface temperatures for arbitrary surface heat flux distributions can be calculated using these influence functions. The influence functions for a circular cylinder and for an in-line square rod array are presented. 14 refs., 9 figs., 1 tab.

  7. Choosing conditions of liquid-phase epitaxy of Insub(1-x)Gasub(x)P solid solutions by statistical methods of experiment planning

    International Nuclear Information System (INIS)

    Batyrev, N.I.; Vigdorovich, V.N.; Selin, A.A.

    1978-01-01

    Insub(1-x)Gasub(x)P(x approximately 0.7) solid solution layers obtained with the help of the phase diagram of the In-InP-GaP system have been studied using statistical methods of experiment planning. The liquidus, baric and solidus surfaces have been plotted for the In-InP-GaP ternary system (In content from 85 to 100 mol.%). Analysis of the results obtained makes it possible to determine the optimum compositions of the melt (x=0.67-0.74) and building-up temperatures (800-850 deg) to obtain epitaxyal Insub(1-x)Gasub(x)P layers

  8. Varying Constants, Gravitation and Cosmology

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Uzan

    2011-03-01

    Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  9. RIFIFI: Analytical calculation method of the critical condition and flux in a varied regions reactor by two-group theory and one dimension developed for the Mercury-Ferranti computer; Rififi: methode de calcul analytique de la condition critique et des flux d'une pile a regions variees en theorie a deux groupes et a une dimension programmee pour le calculateur electronique Mercury (Ferranti)

    Energy Technology Data Exchange (ETDEWEB)

    Amouyal, A; Bacher, P; Lago, B; Mengin, F L; Parker, E [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The calculation method presented in this report has been developed for the Mercury-Ferranti computer of the C.E.N.S. This calculation method allows to resolve the diffusion equations and continuity equations of flux and flow with two groups of neutrons and one dimension in spherical, cylindrical and linear geometry. In the cylindrical and linear configurations, we can take the height and extrapolated radius into account. The critical condition can be realised by varying linearly one or more parameters: k{sub {infinity}}, medium frontier, height or extrapolated radius. The calculation method enables also to calculate the flux, adjoint flux and various integrals. In the first part, it explains what is needed to know before using the method: data presentation, method possibilities, results presentation with some information about restrictions, accuracy and calculation time. The complete formulation of the calculation method is given in the second part. (M.P.)

  10. Varying prior information in Bayesian inversion

    International Nuclear Information System (INIS)

    Walker, Matthew; Curtis, Andrew

    2014-01-01

    Bayes' rule is used to combine likelihood and prior probability distributions. The former represents knowledge derived from new data, the latter represents pre-existing knowledge; the Bayesian combination is the so-called posterior distribution, representing the resultant new state of knowledge. While varying the likelihood due to differing data observations is common, there are also situations where the prior distribution must be changed or replaced repeatedly. For example, in mixture density neural network (MDN) inversion, using current methods the neural network employed for inversion needs to be retrained every time prior information changes. We develop a method of prior replacement to vary the prior without re-training the network. Thus the efficiency of MDN inversions can be increased, typically by orders of magnitude when applied to geophysical problems. We demonstrate this for the inversion of seismic attributes in a synthetic subsurface geological reservoir model. We also present results which suggest that prior replacement can be used to control the statistical properties (such as variance) of the final estimate of the posterior in more general (e.g., Monte Carlo based) inverse problem solutions. (paper)

  11. Boundedness and stability for recurrent neural networks with variable coefficients and time-varying delays

    International Nuclear Information System (INIS)

    Liang Jinling; Cao Jinde

    2003-01-01

    In this Letter, the problems of boundedness and stability for a general class of non-autonomous recurrent neural networks with variable coefficients and time-varying delays are analyzed via employing Young inequality technique and Lyapunov method. Some simple sufficient conditions are given for boundedness and stability of the solutions for the recurrent neural networks. These results generalize and improve the previous works, and they are easy to check and apply in practice. Two illustrative examples and their numerical simulations are also given to demonstrate the effectiveness of the proposed results

  12. 不同温度下α-氨基酸在咖啡碱水溶液中的体积、粘度及折光率特性%Volumetric, Viscometric and Refractive Index Behaviors of α-Amino Acids in Aqueous Caffeine Solution at Varying Temperatures

    Institute of Scientific and Technical Information of China (English)

    Anwar Ali; S.Sabir; M.Tariq

    2007-01-01

    Measurements of density(ρ), viscosity(η), and refractive index(n), were carried out on α-amino acids, DL-solution at 298.15, 303.15, 308.15, and 313.15 K. These measurements have been carried out to evaluate some important parameters, viz., apparent molar volume (φv), partial molar volume (φv0), transfer volume (φ0v (tr)), viscosity A and B coefficients of Jones-Dole equation, free energies of activation per mole of solvent (△μ0#1) and solute (△μ0#2),enthalpies (△H*) and entropies (△S*) of activation of viscous flow, variation of B with temperature ((a)B/(a)T)P, and molar refractive index (RD). These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.

  13. Weighted approximation with varying weight

    CERN Document Server

    Totik, Vilmos

    1994-01-01

    A new construction is given for approximating a logarithmic potential by a discrete one. This yields a new approach to approximation with weighted polynomials of the form w"n"(" "= uppercase)P"n"(" "= uppercase). The new technique settles several open problems, and it leads to a simple proof for the strong asymptotics on some L p(uppercase) extremal problems on the real line with exponential weights, which, for the case p=2, are equivalent to power- type asymptotics for the leading coefficients of the corresponding orthogonal polynomials. The method is also modified toyield (in a sense) uniformly good approximation on the whole support. This allows one to deduce strong asymptotics in some L p(uppercase) extremal problems with varying weights. Applications are given, relating to fast decreasing polynomials, asymptotic behavior of orthogonal polynomials and multipoint Pade approximation. The approach is potential-theoretic, but the text is self-contained.

  14. Estrelas variáveis

    OpenAIRE

    Viana, Sérgio Manuel de Oliveira

    2001-01-01

    A observação do céu nocturno é uma prática que vem da Antiguidade. Desde então e durante muito tempo pensou-se que as estrelas mantinham o brilho constante. Assim foi até ao século XVI, quando David Fabricius observou uma estrela cujo brilho variava periodicamente. Dois séculos mais tarde, Jonh Goodricke descobriu uma segunda estrela e com o desenvolvimento de instrumentos de observação este conjunto foi muito alargado e hoje inclui o Sol.A variação do brilho das estrelas variáveis permite d...

  15. Pemodelan Markov Switching Dengan Time-varying Transition Probability

    OpenAIRE

    Savitri, Anggita Puri; Warsito, Budi; Rahmawati, Rita

    2016-01-01

    Exchange rate or currency is an economic variable which reflects country's state of economy. It fluctuates over time because of its ability to switch the condition or regime caused by economic and political factors. The changes in the exchange rate are depreciation and appreciation. Therefore, it could be modeled using Markov Switching with Time-Varying Transition Probability which observe the conditional changes and use information variable. From this model, time-varying transition probabili...

  16. The interior regularity of pressure associated with a weak solution to the Navier-Stokes equations with the Navier-type boundary conditions

    Czech Academy of Sciences Publication Activity Database

    Neustupa, Jiří; Al Baba, Hind

    2018-01-01

    Roč. 463, č. 1 (2018), s. 222-234 ISSN 0022-247X R&D Projects: GA ČR(CZ) GA17-01747S Institutional support: RVO:67985840 Keywords : Navier-Stokes equation * Navier-type boundary conditions * interior regularity Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.064, year: 2016 https://www. science direct.com/ science /article/pii/S0022247X18302233?via%3Dihub

  17. On robustness of a strong solution to the Navier–Stokes equations with Navier's boundary conditions in the L3-norm

    Czech Academy of Sciences Publication Activity Database

    Kučera, P.; Neustupa, Jiří

    2017-01-01

    Roč. 30, č. 4 (2017), s. 1564-1583 ISSN 0951-7715 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : Navier-Stokes equations * slip boundary conditions * regularity Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.767, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6544/aa6166/meta

  18. The interior regularity of pressure associated with a weak solution to the Navier-Stokes equations with the Navier-type boundary conditions

    Czech Academy of Sciences Publication Activity Database

    Neustupa, Jiří; Al Baba, Hind

    2018-01-01

    Roč. 463, č. 1 (2018), s. 222-234 ISSN 0022-247X R&D Projects: GA ČR(CZ) GA17-01747S Institutional support: RVO:67985840 Keywords : Navier-Stokes equation * Navier-type boundary conditions * interior regularity Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.064, year: 2016 https://www.sciencedirect.com/science/article/pii/S0022247X18302233?via%3Dihub

  19. Flexible Demand Management under Time-Varying Prices

    Science.gov (United States)

    Liang, Yong

    In this dissertation, the problem of flexible demand management under time-varying prices is studied. This generic problem has many applications, which usually have multiple periods in which decisions on satisfying demand need to be made, and prices in these periods are time-varying. Examples of such applications include multi-period procurement problem, operating room scheduling, and user-end demand scheduling in the Smart Grid, where the last application is used as the main motivating story throughout the dissertation. The current grid is experiencing an upgrade with lots of new designs. What is of particular interest is the idea of passing time-varying prices that reflect electricity market conditions to end users as incentives for load shifting. One key component, consequently, is the demand management system at the user-end. The objective of the system is to find the optimal trade-off between cost saving and discomfort increment resulted from load shifting. In this dissertation, we approach this problem from the following aspects: (1) construct a generic model, solve for Pareto optimal solutions, and analyze the robust solution that optimizes the worst-case payoffs, (2) extend to a distribution-free model for multiple types of demand (appliances), for which an approximate dynamic programming (ADP) approach is developed, and (3) design other efficient algorithms for practical purposes of the flexible demand management system. We first construct a novel multi-objective flexible demand management model, in which there are a finite number of periods with time-varying prices, and demand arrives in each period. In each period, the decision maker chooses to either satisfy or defer outstanding demand to minimize costs and discomfort over a certain number of periods. We consider both the deterministic model, models with stochastic demand or prices, and when only partial information about the stochastic demand or prices is known. We first analyze the stochastic

  20. Exploring representations and experiences of case-management users: towards difficulties and solutions to leading qualitative interviews with older people with complex living conditions.

    Science.gov (United States)

    Balard, Frédéric; Corre, Stéphanie Pin Le; Trouvé, Hélène; Saint-Jean, Olivier; Somme, Dominique

    2013-01-01

    By matching needs to resource services, case management could be a useful tool for improving the care of older people with complex living conditions. Collecting and analysing the users' experiences represents a good way to evaluate the effectiveness and efficiency of a case-management service. However, in the literature, fieldwork is very rarely considered and the users included in qualitative research seem to be the most accessible. This study was undertaken to describe the challenges of conducting qualitative research with older people with complex living conditions in order to understand their experiences with case-management services. Reflective analysis was applied to describe the process of recruiting and interviewing older people with complex living conditions in private homes, describing the protocol with respect to fieldwork chronology. The practical difficulties inherent in this type of study are addressed, particularly in terms of defining a sample, the procedure for contacting the users and conducting the interview. The users are people who suffer from a loss of autonomy because of cognitive impairment, severe disease and/or psychiatric or social problems. Notably, most of them refuse care and assistance. Reflective analysis of our protocol showed that the methodology and difficulties encountered constituted the first phase of data analysis. Understanding the experience of users of case management to analyse the outcomes of case-management services requires a clear methodology for the fieldwork.