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Sample records for current potential drop

  1. Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

    OpenAIRE

    Li Yuting; Gan Fangji; Wan Zhengjun; Liao Junbi; Li Wenqiang

    2015-01-01

    Potential drop techniques are of two types: the direct current potential drop (DCPD) technique and alternating current potential drop (ACPD) technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of s...

  2. Evaluation of the Transient Eddy Current Potential Drop of a Four Point Probe

    Science.gov (United States)

    Bowler, J. R.

    2009-03-01

    The transient electrical potential drop of a four point probe has been calculated for the case where a current pulse is injected into a conductive plate via two surface contact electrodes and the voltage measured between two other contact electrodes. The four contact points can be co-linear but this is not always case. For example, they can form a rectangle. Usually such probes carry direct current or alternating current and are used to measure electrical conductivity, crack dimensions or variations of conductivity and magnetic permeability with depth. However, the advantage of a current pulse excitation is that information on the variations of material properties with depth can be acquired rapidly and conveniently. What is needed is a means to infer material properties such as the conductivity variations with depth from the transient field measurements. Here, as an initial step in developing this analysis, we report on the evaluation of transient potential drop signals for four point probes on a homogeneous conductive plates.

  3. On-Line Monitoring of Environment-Assisted Cracking in Nuclear Piping Using Array Probe Direct Current Potential Drop

    OpenAIRE

    Kim, Y.; Choi, S.; Yoon, J. Y.; Nam, W. C.; Hwang, I. S.; Bromberg, Leslie; Stahle, Peter W; Ballinger, Ronald G

    2015-01-01

    A direct current potential drop method utilizing array probes with measurement ends maintaining an equalized potential designated as equi-potential switching array probe direct current potential drop (ESAP-DCPD) technique has been developed earlier at Seoul National University. This paper validates ESAP-DCPD technique by showing consistency among experimental measurements, analytical solution and numerical predictions using finite element analysis (FEA) of electric field changes with crack gr...

  4. Edge effects in four-point direct current potential drop measurements on metal plates

    International Nuclear Information System (INIS)

    Lu, Y; Bowler, N; Bowler, J R; Huang, Y

    2009-01-01

    Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

  5. Edge effects in four-point direct current potential drop measurements on metal plates

    Science.gov (United States)

    Lu, Y.; Bowler, N.; Bowler, J. R.; Huang, Y.

    2009-07-01

    Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

  6. Dynamic fracture testing of ferritic steels using direct current potential drop method

    International Nuclear Information System (INIS)

    Oh, Y. J.; Kim, J. H.; Hwang, I. S.; Park, Y. W.

    2000-01-01

    To apply leak-before-break (LBB) concept to nuclear pipes, the dynamic strain aging of low carbon steel materials has to be considered. For this goal, the J-R tests are needed over a range of temperatures and loading rates, including rapid dynamic loading conditions. In dynamic J-R tests, the unloading compliance method can not be applied and usually the direct current potential drop (DCPD) method has been used. But, even the DCPD method was known to have the problem in defining the crack initiation point due to a potential peak arising in early part of loading of ferromagnetic materials. In this study, potential peaks characteristics were investigated for SA106Gr.C piping steels, and the definition of crack initiation point was made by back tracking from final physical crack length, and it was proposed that this technique could be applied to DCPD method in dynamic loading J-R test

  7. Four-point probe measurements of a direct current potential drop on layered conductive cylinders

    International Nuclear Information System (INIS)

    Lu, Yi; Bowler, John R

    2012-01-01

    We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green’s function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results. (paper)

  8. Four-point probe measurements of a direct current potential drop on layered conductive cylinders

    Science.gov (United States)

    Lu, Yi; Bowler, John R.

    2012-11-01

    We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green’s function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results.

  9. Influence of crack length on crack depth measurement by an alternating current potential drop technique

    International Nuclear Information System (INIS)

    Raja, Manoj K; Mahadevan, S; Rao, B P C; Behera, S P; Jayakumar, T; Raj, Baldev

    2010-01-01

    An alternating current potential drop (ACPD) technique is used for sizing depth of surface cracks in metallic components. Crack depth estimations are prone to large deviations when ACPD measurements are made on very shallow and finite length cracks, especially in low conducting materials such as austenitic stainless steel (SS). Detailed studies have been carried out to investigate the influence of crack length and aspect ratio (length to depth) on depth estimation by performing measurements on electric discharge machined notches with the aspect ratio in the range of 1 to 40 in SS plates. In notches with finite length, an additional path for current to flow through the surface along the length is available causing the notch depths to be underestimated. The experimentally observed deviation in notch depth estimates is explained from a simple mathematical approach using the equivalent resistive circuit model based on the additional path available for the current to flow. A scheme is proposed to accurately measure the depth of cracks with finite lengths in SS components

  10. A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water

    International Nuclear Information System (INIS)

    Anzai, Hideya; Ishibashi, Ryo; Saka, Masumi

    2016-01-01

    To establish an evaluation technique for oxide film thickness in-situ, the applicability of a four-point-probe direct current potential drop method is discussed in this study. Several samples of JIS SUS316L stainless steel with different oxide film thickness were prepared after immersing them in oxygenated pure water at 288°C for different periods. The oxide film thickness was measured by cross sectional observation using a transmission electron microscope. Potential drop on the oxide surface was measured every second during an acquisition period of about 20 s while a constant current was being injected into the sample simultaneously. This kind of measurement was repeatedly carried out at several arbitrary contact positions on the surface of the same sample. The measurement results showed that the potential drop slightly changed during the acquisition period and the tendency varied at the different contact positions. Multiple measurements at different contact positions revealed that the tendency could be categorized into two general types: the decreasing potential drop and the increasing potential drop, defined by the overall trend of the potential drop during the acquisition time. It was found that the ratio of contact positions with a decreasing potential drop tendency to all the contact positions of measurement tended to increase as applied current increased. This tendency depended on the oxide film thickness. The threshold value of applied current was found to correlate well with the oxide film thickness when the occurrence rate of decreasing potential drop ranged from 70 to 90% showing the best correlation at 70%. (author)

  11. Development of a piping thickness monitoring system using equipotential switching direct current potential drop method

    International Nuclear Information System (INIS)

    Kyung Ha, Ryu; Na Young, Lee; Il Soon, Hwang

    2007-01-01

    As nuclear power plants age, low alloy steel piping undergoes wall thickness reduction due to Flow Accelerated Corrosion (FAC). Persisting pipe rupture accidents prompted thinned pipe management programs. As a consequence extensive inspection activities are made based on the Ultrasonic Technique (UT). As the inspection points increase, time is needed to cover required inspection areas. In this paper, we present the Wide Range Monitoring (WiRM) concept with Equipotential Switching Direct Current Potential Drop (ES-DCPD) method by which FAC-active areas can be screened for detailed UT inspections. To apply ES-DCPD, we developed an electric resistance network model and electric field model based on Finite Element Analysis (FEA) to verify its feasibility. Experimentally we measured DCPD of the pipe elbow and confirmed the validity using UT inspections. For a more realistic validation test, we designed a high temperature flow test loop with environmental parameters turned for FAC simulation in the laboratory. Using electrochemical monitoring of water chemistry and local flow velocity prediction by computational fluid dynamic model, FAC rate is estimated. Based on the FAC prediction model and the simulation loop test, we plan to demonstrate the applicability of ES-DCPD in the PWR secondary environment. (authors)

  12. Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

    Science.gov (United States)

    Li, Yuting; Gan, Fangji; Wan, Zhengjun; Liao, Junbi; Li, Wenqiang

    2015-10-01

    Potential drop techniques are of two types: the direct current potential drop (DCPD) technique and alternating current potential drop (ACPD) technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

  13. Characterizing Ductile Damage and Failure: Application of the Direct Current Potential Drop Method to Uncracked Tensile Specimens

    OpenAIRE

    Brinnel, V.; Döbereiner, B.; Münstermann, Sebastian

    2014-01-01

    Modern high-strength steels exhibit excellent ductility properties but their application is hindered by traditional design rules. A characterization of necessary safety margins for the ductile failure of these steels is therefore required. Direct observation of ductile damage within tests is currently not possible, only limited measurements can be made with synchrotron or X-ray radiation facilities. The direct current potential drop (DCPD) method can determine ductile crack propagation with l...

  14. Novel Method for Sizing Metallic Bottom Crack Depth Using Multi-frequency Alternating Current Potential Drop Technique

    Directory of Open Access Journals (Sweden)

    Li Yuting

    2015-10-01

    Full Text Available Potential drop techniques are of two types: the direct current potential drop (DCPD technique and alternating current potential drop (ACPD technique, and both of them are used in nondestructive testing. ACPD, as a kind of valid method in sizing metal cracks, has been applied to evaluate metal structures. However, our review of most available approaches revealed that some improvements can be done in measuring depth of metal bottom crack by means of ACPD, such as accuracy and sensitivity of shallow crack. This paper studied a novel method which utilized the slope of voltage ratio-frequency curve to solve bottom crack depth by using a simple mathematic equation based on finite element analysis. It is found that voltage ratio varies linearly with frequency in the range of 5-15 Hz; this range is slightly higher than the equivalent frequency and lower than semi-permeable frequency. Simulation and experiment show that the novel method can measure the bottom crack depth accurately.

  15. The development of crack measurement system using the direct current potential drop method for use in the hot cell

    International Nuclear Information System (INIS)

    Kim, Do-Sik; Ahn, Sang-Bok; Lee, Key-Soon; Kim, Yong-Suk; Kwon, Sang-Chul

    1999-01-01

    The crack length measurement system using the direct current potential drop (DCPD) method was developed for the detection of crack growth initiation and subsequent crack growth. The experimental precautions and data processing procedure required for its application were also described find discussed. The system presented herein was specially built for use in fracture toughness testing of unirradiated or irradiated pressure tube materials from nuclear reactor. The application of this system for fracture toughness determination was illustrated from the test of curved compact tension specimens removed from CANDU reactor pressure tubes. The crack extension was monitored using the DCPD method. It is found that the changes of the potential drop and the changes of the crack length have a linear relationship. The final crack front was marked by heat-tinting after the test and the specimen broken open for determination of the initial and final physical crack length. The physical crack lengths, obtained by the 9-point average method described in ASTM E1737-96 on heat-tinted fracture surface, were used to calibrate the DCPD method for each test on an individual basis by matching the change in voltage to the crack extension. It is found that this system can be recommended for determination of the J-integral resistance (J-R) curve of unirradiated or irradiation materials in the hot cell, especially when testing at elevated temperature and in the environment chamber or furnace. (author)

  16. Online monitoring method using Equipotential Switching Direct Current potential drop for piping wall loss by flow accelerated corrosion

    International Nuclear Information System (INIS)

    Ryu, Kyung Ha; Lee, Tae Hyun; Kim, Ji Hak; Hwang, Il Soon; Lee, Na Young; Kim, Ji Hyun; Park, Jin Ho; Sohn, Chang Ho

    2010-01-01

    The flow accelerated corrosion (FAC) phenomenon persistently impacts plant reliability and personnel safety. We have shown that Equipotential Switching Direct Current Potential Drop (ES-DCPD) can be employed to detect piping wall loss induced by FAC. It has been demonstrated to have sufficient sensitivity to cover both long and short lengths of piping. Based on this, new FAC screening and inspection approaches have been developed. For example, resolution of ES-DCPD can be adjusted according to its monitoring purpose. The developed method shows good integrity during long test periods. It also shows good reproducibility. The Seoul National University FAC Accelerated Simulation Loop (SFASL) has been constructed for ES-DCPD demonstration purposes. During one demonstration, the piping wall was thinned by 23.7% through FAC for a 13,000 min test period. In addition to the ES-DCPD method, ultrasonic technique (UT) has been applied to SFASL for verification while water chemistry was continually monitored and controlled using electrochemical sensors. Developed electrochemical sensors showed accurate and stable water conditions in the SFASL during the test period. The ES-DCPD results were also theoretically predicted by the Sanchez-Caldera's model. The UT, however, failed to detect thinning because of its localized characteristics. Online UT that covers only local areas cannot assure the detection of wall loss.

  17. Numerical simulations of electric potential field for alternating current potential drop associated with surface cracks in low-alloy steel nuclear material

    Science.gov (United States)

    Yeh, Chun-Ping; Huang, Jiunn-Yuan

    2018-04-01

    Low-alloy steels used as structural materials in nuclear power plants are subjected to cyclic stresses during power plant operations. As a result, cracks may develop and propagate through the material. The alternating current potential drop technique is used to measure the lengths of cracks in metallic components. The depth of the penetration of the alternating current is assumed to be small compared to the crack length. This assumption allows the adoption of the unfolding technique to simplify the problem to a surface Laplacian field. The numerical modelling of the electric potential and current density distribution prediction model for a compact tension specimen and the unfolded crack model are presented in this paper. The goal of this work is to conduct numerical simulations to reduce deviations occurring in the crack length measurements. Numerical simulations were conducted on AISI 4340 low-alloy steel with different crack lengths to evaluate the electric potential distribution. From the simulated results, an optimised position for voltage measurements in the crack region was proposed.

  18. Evaluation of J-R curve testing of nuclear piping materials using the direct current potential drop technique

    International Nuclear Information System (INIS)

    Hackett, E.M.; Kirk, M.T.; Hays, R.A.

    1986-08-01

    A method is described for developing J-R curves for nuclear piping materials using the DC Potential Drop (DCPD) technique. Experimental calibration curves were developed for both three point bend and compact specimen geometries using ASTM A106 steel, a type 304 stainless steel and a high strength aluminum alloy. These curves were fit with a power law expression over the range of crack extension encountered during J-R curve tests (0.6 a/W to 0.8 a/W). The calibration curves were insensitive to both material and sidegrooving and depended solely on specimen geometry and lead attachment points. Crack initiation in J-R curve tests using DCPD was determined by a deviation from a linear region on a plot of COD vs. DCPD. The validity of this criterion for ASTM A106 steel was determined by a series of multispecimen tests that bracketed the initiation region. A statistical differential slope procedure for determination of the crack initiation point is presented and discussed. J-R curve tests were performed on ASTM A106 steel and type 304 stainless steel using both the elastic compliance and DCPD techniques to assess R-curve comparability. J-R curves determined using the two approaches were found to be in good agreement for ASTM A106 steel. The applicability of the DCPD technique to type 304 stainless steel and high rate loading of ferromagnetic materials is discussed. 15 refs., 33 figs

  19. A study on induced current focusing potential drop (ICFPD) technique. Examination of the sizing accuracy of defects and its frequency dependence

    International Nuclear Information System (INIS)

    Kim, Hoon; Shoji, Tetsuo

    1994-01-01

    Aiming at nondestructive detection and size prediction of defects with high accuracy and resolution, an Induced Current Focusing Potential Drop (ICFPD) technique has been developed. This technique can be applied for determining the location and size of defects in components with not only simple shape such as plain surface but also more complex shape and geometry such as curved surface and dissimilar joint. This paper describes the basic principle of ICFPD and its probe development. In this ICFPD, current was induced in a conductive material by a straight induction wire, which is electrically isolated, placed on it. The benefits of this new technique compared with the conventional ACPD are: (1) Current is induced and focused only at an explorating region. (2) Applicable to defect detection by scanning the sensor probe in an explorating region. (3) Applicable to defect detection in a weld joint of austenitic stainless steel. As the results of the innovation in instrumentation and the improvement in evaluation procedure by use of suitable parameters, the existence of defects is clearly observed as the variation of potential drops, and the nondimensional parameter (V c,max. /V avg. ) has a direct correlation with crack depth. Especially, for the depth less than 5 mm, the ICFPD shows higher sensitivity than the conventional ACPD at the frequencies of 3, 10 and 30 kHz. (author)

  20. Signal sensitivity of alternating current potential drop measurement for crack detection of conductive substrate with tunable coating materials through finite element modeling

    International Nuclear Information System (INIS)

    Rao, Simha Sandeep; Zhao, Huijuan; Liu, Ming; Peng, Fei; Zhang, Bo

    2016-01-01

    We adopt a finite element numerical modeling approach to investigate the electromagnetic coupling effect of two parallel electric conductors with tunable electric conductivity σ and magnetic permeability μ . For two parallel conductors C and S ( μ C   ⋅  σ C   ≤  μ S   ⋅  σ S ), we find that the shape of current density profile of conductor S is dependent on the product of μ C   ⋅  σ C , while the magnitude is determined by the AC current frequency f . On the other hand, the frequency f affects not only the shape but also the magnitude of the current density profile of conductor C. We further adopt a coplanar model to investigate the signal sensitivity of alternating current potential drop (ACPD) measurement for both surface crack and inner crack detection. We find that with modified coating materials (lower electric conductivity and higher magnetic permeability, compared with the substrate material properties), the crack detection signal sensitivity can be greatly enhanced for both the cracks within the coating and at the coating/substrate interface, where cracks are most commonly encountered in real situations. (paper)

  1. Verification of the Viability of Equipotential Switching Direct Current Potential Drop Method for Piping Wall Loss Monitoring with Signal Sensitivity Analysis

    International Nuclear Information System (INIS)

    Ryu, Kyung Ha; Hwang, Il Soon; Kim, Ji Hyun

    2008-01-01

    Flow accelerated corrosion (FAC) phenomenon of low alloy carbon steels in nuclear power plant has been known as one of major degradation mechanisms. It has a potential to cause nuclear pipe rupture accident which may directly impact on the plant reliability and safety. Recently, the equipotential switching direct current potential drop (ES-DCPD) method has been developed, by the present authors, as a method to monitor wall loss in a piping. This method can rapidly monitor the thinning of piping, utilizing either the wide range monitoring (WiRM) or the narrow range monitoring (NaRM) technique. WiRM is a method to monitor wide range of straight piping, whereas NaRM focuses significantly on a narrow range such as an elbow. WiRM and NaRM can improve the reliability of the current FAC screening method that is based on computer modeling on fluid flow conditions. In this paper, the measurements by ES-DCPD are performed with signal sensitivity analyses in the laboratory environment for extended period and showed the viability of ES-DCPD for real plant applications.

  2. An analysis of pipe degradation shape using potential drop method

    International Nuclear Information System (INIS)

    Jegal, S.; Lee, S. H.

    1999-01-01

    The Potential Drop (PD) method, one of NDE (Non-Destructive Evaluation) method is used to analyze the thickness distribution of pipes degraded by FAC (Flow Accelerated Corrosion). A DCPD (Direct Current Potential Drop) system which can measure PD for direct current was made, and the specimens with line defects and cylinder type defects have been used for experiments to prove the theory of Potential Drop method and to find out the effects of each factors. The experiment to find out defect distributions has been performed and it is found that PD method can analyze almost correct position of defects

  3. Potential drop sensors for sodium loops

    International Nuclear Information System (INIS)

    Selvaraj, R.

    1978-11-01

    Potential drop sensors to detect the presence or the absence of sodium in pipe lines are described. These are very handy during loop charging and dumping operations. Their suitability to detect level surges and to monitor continuous level of liquid metals in certain applications is discussed. (author)

  4. Potential drop crack measurement systems for CANDU components

    Energy Technology Data Exchange (ETDEWEB)

    Sahney, R [Carleton Univ., Ottawa, ON (Canada)

    1994-12-31

    A project to develop an automated crack measurement system for CANDU pressure tube burst testing is currently underway. The system will utilize either Direct Current Potential Drop (DCPD) or Alternating Current Potential Drop (ACPD) techniques for crack measurement. The preliminary stage of the project involves testing and comparison of both ACPD and DCPD methods on a Zr - 2.5% Nb alloy plate with saw cuts (used to simulate cracks). Preliminary results show that both ACPD and DCPD techniques are capable of detecting cracks; further testing is in progress to determine the ability of each of the two systems to make accurate crack depth measurements. This paper will describe the two potential drop techniques and will present test results from the experimental program. (author). 10 refs., 7 figs.

  5. Vlasov simulations of parallel potential drops

    Directory of Open Access Journals (Sweden)

    H. Gunell

    2013-07-01

    Full Text Available An auroral flux tube is modelled from the magnetospheric equator to the ionosphere using Vlasov simulations. Starting from an initial state, the evolution of the plasma on the flux tube is followed in time. It is found that when applying a voltage between the ends of the flux tube, about two thirds of the potential drop is concentrated in a thin double layer at approximately one Earth radius altitude. The remaining part is situated in an extended region 1–2 Earth radii above the double layer. Waves on the ion timescale develop above the double layer, and they move toward higher altitude at approximately the ion acoustic speed. These waves are seen both in the electric field and as perturbations of the ion and electron distributions, indicative of an instability. Electrons of magnetospheric origin become trapped between the magnetic mirror and the double layer during its formation. At low altitude, waves on electron timescales appear and are seen to be non-uniformly distributed in space. The temporal evolution of the potential profile and the total voltage affect the double layer altitude, which decreases with an increasing field aligned potential drop. A current–voltage relationship is found by running several simulations with different voltages over the system, and it agrees with the Knight relation reasonably well.

  6. Four-point potential drop measurements for materials characterization

    International Nuclear Information System (INIS)

    Bowler, Nicola

    2011-01-01

    The technique of measuring the voltage difference (potential drop) between two of the four electrodes of a four-point probe, in order to determine conductivity or surface resistivity of a test piece, is well established in the direct-current (dc) or quasi-dc regime. The technique finds wide usage in the semiconductor industry for the purpose of measuring surface resistivity of semiconductors, and also in the measurement of conductivity of metals, particularly of ferromagnetic metals for which conductivity cannot be easily measured using eddy-current nondestructive evaluation (NDE). In these applications, the conductivity of the test piece is deduced from an analytic formula that depends on the geometry of the probe and test piece. Such a formula requires, as an input, the measured value of the potential drop. Several analytical expressions exist for a variety of test-piece geometries and probe arrangements. Recently, it has been shown that broadband measurements of the potential drop, known as 'alternating current potential drop' (ac PD) measurements, can be used not only to obtain the conductivity of a test piece, but also its linear permeability μ. The beauty of this measurement is that the two parameters are completely decoupled in the quasi-static regime. In fact, μ does not appear in the quasi-static expression for σ. Hence, σ may be obtained from low-frequency ac PD measurements and then μ may be deduced as the frequency increases beyond the quasi-static regime, once σ is known. In this review, both dc and ac solutions that are useful in determining the conductivity of metals and semiconductors, and the permeability of ferromagnetic conductors, are summarized. In particular, flat test pieces with arbitrary thickness are considered. At the next level of complexity, a solution for a half-space coated with a surface layer is given, along with a discussion of the use of the four-point potential drop method for determining thickness of a surface layer, such

  7. A FAST study of quasi-static structure ("Inverted-V") potential drops and their latitudinal dependence in the premidnight sector and ramifications for the current-voltage relationship

    Science.gov (United States)

    Dombeck, J.; Cattell, C.; McFadden, J.

    2013-09-01

    Utilizing FAST satellite electron measurements, we present the first reported investigation of the dependency on latitude of quasi-static structure ("inverted-V") potential drop magnitude (Φ). A trend of lower Φ at lower latitudes in the premidnight sector on field lines with dark foot points was observed. This trend is supported both statistically and in individual satellite crossings. The existence of two distinct peaks in occurrence probability for Φ was also observed: one between ~2 kV and 10 kV and the other at somewhat less than 1 kV. The relative occurrence of structures with Φ in the higher (>2 kV) peak is significantly reduced with decreasing latitude. This partially accounts for the statistical trend of lower potential drop magnitudes at lower latitudes. The two Φ occurrence frequency peaks correspond to two different regimes (one with eΦ/kTe ~ or > 1 and one with eΦ/kTe current-voltage relation where source electron density rather than Φ is most directly controlled by the field-aligned current density. These observations and their ramifications represent a significant step forward in the understanding of field-aligned currents, auroral acceleration, and magnetospheric-ionospheric coupling.

  8. Compensation of the skin effect in low-frequency potential drop measurements

    OpenAIRE

    Corcoran, J; Nagy, PB

    2016-01-01

    Potential drop measurements are routinely used in the non-destructive evaluation of component integrity. Potential drop measurements use either direct current (DC) or alternating current (AC), the latter will have superior noise performance due to the ability to perform phase sensitive detection and the reduction of flicker noise. AC measurements are however subject to the skin effect where the current is electromagnetically constricted to the surface of the component. Unfortunately, the skin...

  9. Evaluation of the crack initiation of curved compact tension specimens of a Zr-2.5Nb pressure tube using the unloading compliance and direct current potential drop methods

    International Nuclear Information System (INIS)

    Kim, Young Suk; Jeong, Hyeon Cheol; Ahn, Sang Bok

    2005-01-01

    The Direct Current Potential Drop(DCPD) method and the Unloading Compliance(UC) method with a crack opening displacement gauge were applied simultaneously to the Zr-2.5Nb Curved Compact Tension (CCT) specimens to determine which of the two methods can precisely determine the crack initiation point and hence the crack length for evaluation of their fracture toughness. The DCPD method detected the crack initiation at a smaller load-time displacement compared to the UC method. As a verification, a direct observation of the fracture surfaces on the curved compact tension specimens was made on the CCT specimens experiencing either 0.8 to 1.0 mm load line displacement or various loads from 50% to 80% of the maximum peak load, or P max . The DCPD method is concluded to be more precise in determining the crack initiation and fracture toughness, J in Zr-2.5Nb CCT specimens than the UC method

  10. Evaluation of the crack initiation of curved compact tension specimens of a Zr-2.5Nb pressure tube using the unloading compliance and direct current potential drop methods

    International Nuclear Information System (INIS)

    Jeong, Hyeon Cheol; Ahn, Sang Bok; Park, Joong Chul; Kim, Young Suk

    2005-01-01

    Zr-2.5Nb pressure tubes, carrying fuel bundles and heavy water coolant inside, degrade due to neutron irradiation and hydrogen embrittlement during their operation in heavy water reactors. The safety criterion for the Zr-2.5Nb tubes to meet is a leak-before-break (LBB) requirement. To evaluate a safety margin related to the LBB criterion, facture toughness of the pressure tubes are to be determined periodically with their operational time. For a reliable evaluation of the LBB safety criterion of the pressure tubes, it is required to precisely determine their fracture toughness. Since the fracture toughness or J of the pressure tubes is determined only by the extended crack length, it is important to reliably and precisely evaluate the advanced crack length. However, the problem lies with the detection of the crack opening point because prior plastic deformation before a start of the crack makes it difficult. The aim of this work is to evaluate which method can define the crack initiation point in the Zr- 2.5Nb compact tension specimens more precisely between the unloading compliance method with a crack opening displacement (COD) gauge and the direct current potential drop (DCPD) methods

  11. Experimental observations of anomalous potential drops over ion density cavities

    International Nuclear Information System (INIS)

    Bohm, M.

    1991-08-01

    Experiments are reported showing the plasma potential response when a step voltage is applied over the plasma column between the two plasma sources in a triple plasma machine. The time resolution is sufficient to resolve potential variations caused essentially by the electron motion, and two independent probe methods are used to obtain this time resolution. Depending on the initial conditions two different responses were observed on the time scale of the electron motion. When the initial ion density varies along the plasma column and has a local minimum (that is, forms an ion density cavity), the applied potential drop becomes distributed over the cavity after a few electron transit times. Later the profile steepens to a double layer on the time scale of the ion motion. The width of the cavity is comparable to the length of the plasma column. When the initial density is axially uniform, most of the potential drop instead concentrates to a narrow region at the low potential end of the plasma column after a few electron transit times. On the time scale of the ion motion this potential drop begins to propagate into the plasma as a double layer. The results obtained are consistent with those from numerical simulations with similar boundary conditions. Further experiments are necessary to get conclusive insight into the voltage supporting capability of an ion density cavity. (au) (34 refs.)

  12. In-Situ Creep Monitoring Using the Potential Drop Method

    Science.gov (United States)

    Madhi, E.; Sposito, G.; Davies, C. M.; Cawley, P.; Nagy, P. B.

    2011-06-01

    A directional low-frequency Alternating Current Potential Drop (ACPD) sensor was developed for in-situ monitoring of creep in metals. The sensor relies on a modified ACPD technique that measures simultaneously both values of resistance in the axial and lateral directions using a square electrode configuration. As compared to the more commonly used in-line electrode configuration, the square arrangement used in this sensor is much more directional and thus allows the detection of creep-induced anisotropy and texture. The technique monitors the variation in the ratio of the measured axial and lateral resistances, therefore can efficiently separate the mostly isotropic common part of the resistivity variation caused by reversible temperature variations from the mostly anisotropic differential part caused by direct geometrical and indirect material effects of creep. Initially, this ratio is roughly proportional to the axial creep strain, while at later stages, the resistance ratio increases even faster with creep strain because of the formation of directional discontinuities such as preferentially oriented grain boundary cavities and multiple-site microcracks in the material.

  13. Detection and sizing of cracks using potential drop techniques based on electromagnetic induction

    International Nuclear Information System (INIS)

    Sato, Yasumoto; Kim, Hoon

    2011-01-01

    The potential drop techniques based on electromagnetic induction are classified into induced current focused potential drop (ICFPD) technique and remotely induced current potential drop (RICPD) technique. The possibility of numerical simulation of the techniques is investigated and the applicability of these techniques to the measurement of defects in conductive materials is presented. Finite element analysis (FEA) for the RICPD measurements on the plate specimen containing back wall slits is performed and calculated results by FEA show good agreement with experimental results. Detection limit of the RICPD technique in depth of back wall slits can also be estimated by FEA. Detection and sizing of artificial defects in parent and welded materials are successfully performed by the ICFPD technique. Applicability of these techniques to detection of cracks in field components is investigated, and most of the cracks in the components investigated are successfully detected by the ICFPD and RICPD techniques. (author)

  14. Continuous monitoring of back-wall stress corrosion cracking propagation by means of potential drop techniques

    International Nuclear Information System (INIS)

    Sato, Yasumoto; Atsumi, Takeo; Shoji, Tetsuo

    2006-01-01

    In order to investigate the applicability of the potential drop techniques to the continuous monitoring of stress corrosion cracking (SCC) propagation, SCC tests were performed in a sodium thiosulfate solution at room temperature using plate specimens with weldments. The SCC propagation was monitored using the techniques of direct current potential drop (DCPD), alternating current potential drop (ACPD) and modified induced current potential drop (MICPD) on the reverse side that on which the SCC existed and effectiveness of each technique for the continuous monitoring from the reverse side of SCC was compared from the viewpoints of sensitivity to the crack propagation and measurement stability. The MICPD and DCPD techniques permit continuous monitoring of the back-wall SCC propagation, which initiates from a fatigue pre-crack at a depth of about 4 mm, from which it propagates through more than 80% of the specimen thickness. The MICPD technique can decrease the effect of the current flowing in the direction of the crack length by focusing the induced current into the local area of measurement using induction coils, so that the sensitivity of the continuous monitoring of the back wall SCC propagation is higher than that of the DCPD and ACPD techniques. (author)

  15. Potential drop technique for monitoring stress corrosion cracking growth

    International Nuclear Information System (INIS)

    Neves, Celia F.C.; Schvartzman, Monica M.A.M.; Moreira, Pedro A.L.D.P.L.P.

    2002-01-01

    Stress corrosion cracking is one of most severe damage mechanisms influencing the lifetime of components in the operation of nuclear power plants. To assess the initiation stages and kinetics of crack growth as the main parameters coming to residual lifetime determination, the testing facility should allow active loading of specimens in the environment which is close to the real operation conditions of assessed component. Under cooperation of CDTN/CNEN and International Atomic Energy Agency a testing system has been developed by Nuclear Research Institute, Czech Republic, that will be used for the environmentally assisted cracking testing at CDTN/CNEN. The facility allows high temperature autoclave corrosion mechanical testing in well-defined LWR water chemistry using constant load, slow strain rate and rising displacement techniques. The facility consists of autoclave and refreshing water loop enabling testing at temperatures up to 330 deg C. Active loading system allows the maximum load on a specimen as high as 60 kN. The potential drop measurement is used to determine the instant crack length and its growth rate. The paper presents the facility and describes the potential drop technique, that is one of the most used techniques to monitor crack growth in specimens under corrosive environments. (author)

  16. Continuous monitoring of back wall stress corrosion cracking growth in sensitized type 304 stainless steel weldment by means of potential drop techniques

    OpenAIRE

    SATO, Y; ATSUMI, T; SHOJI, T

    2007-01-01

    Stress corrosion cracking (SCC) tests on welded specimens of sensitized type 304SS with a thickness of 20 mm were performed in sodium thiosulphate solution at room temperature, with continuous monitoring of the SCC growth, using the techniques of modified induced current potential drop (MICPD), alternating current potential drop (ACPD) and direct current potential drop (DCPD). The MICPD and DCPD techniques permit continuous monitoring of the back wall SCC, which initiates from a fatigue pre-c...

  17. Evaluation of the nugget diameter in spot welded joints between two steel sheets by means of a potential drop technique

    International Nuclear Information System (INIS)

    Tohmyoh, Hironori; Ikarashi, Hidetomo; Matsui, Yoichi; Hasegawa, Yuta; Obara, Satoshi

    2015-01-01

    A potential drop technique which utilizes the electrical circuit used in resistance spot welding is reported. Spot welded samples comprising two steel sheets were inserted between the two Cu electrodes and a constant direct current was supplied between the electrodes. The potential drop between two points, one on each electrode, was determined by analysis for various values of nugget diameter and various values of the contact resistance between the Cu electrodes and the steel sheet sample. The nugget diameter of the spot welded joint could be quantitatively evaluated from the measured potential drop and the equation obtained from the analysis. (paper)

  18. Evaluation of the nugget diameter in spot welded joints between two steel sheets by means of a potential drop technique

    Science.gov (United States)

    Tohmyoh, Hironori; Ikarashi, Hidetomo; Matsui, Yoichi; Hasegawa, Yuta; Obara, Satoshi

    2015-08-01

    A potential drop technique which utilizes the electrical circuit used in resistance spot welding is reported. Spot welded samples comprising two steel sheets were inserted between the two Cu electrodes and a constant direct current was supplied between the electrodes. The potential drop between two points, one on each electrode, was determined by analysis for various values of nugget diameter and various values of the contact resistance between the Cu electrodes and the steel sheet sample. The nugget diameter of the spot welded joint could be quantitatively evaluated from the measured potential drop and the equation obtained from the analysis.

  19. Stability of alternating current discharges between water drops on insulation surfaces

    International Nuclear Information System (INIS)

    Rowland, S M; Lin, F C

    2006-01-01

    Discharges between water drops are important in the ageing of hydrophobic outdoor insulators. They may also be important in the processes leading up to flashover of these insulators in high pollution conditions. This paper considers discharges between drops when a limited alternating current is available, as experienced by an ageing insulator in service. A phenomenon is identified in which the length of a discharge between two drops is reduced through a particular type of distortion of the drops. This is visually characterized as a liquid protrusion from each of a pair of water drops along the insulator surface. This process is distinct from vibration of the drops, general distortion of their shape and the very fast emission of jet streams seen in very high fields. The process depends upon the discharge current, the resistivity of the moisture and the hydrophobicity of the insulation surface

  20. The use of potential drop techniques for the evaluation of environment assisted cracking of austenitic alloys

    International Nuclear Information System (INIS)

    Lidar, P.; Hwang, I.S.; Ballinger, R.G.

    1992-01-01

    The DC potential drop technique has been adapted for strain measurements. An AC potential drop technique has been developed for crack detection. It has been demonstrated that a DC with switched polarity can have a strain accuracy of ±0.12% after yielding and a multi-frequency AC system with up to 200 kHz frequency can have a sensitivity of 50 μm for crack detection. The techniques have been applied to environment assisted cracking tests of Ni-Cr-Fe alloys in 350 degrees C water and austenitic stainless steel in 288 degrees C water using both static and dynamic loading. Long term signal stability is maintained given: (1) rigid probe attachments; (2) local preamplification; and (3) adequate lead grounding and shielding. The AC potential drop technique is found to be more suitable for constant load than for dynamic loading and is also compatible with aggressive environments. During dynamic loading, sensitivity can be significantly reduced due to serrated yielding. An analytical model has been developed to predict the DC and AC potential drops in a round bar geometry. A sensitivity analysis has been made to determine test to test variation associated with variations in supplied current, specimen dimensions, and probe spacing. Multifrequency analysis shows that the measured data agrees with the prediction at frequencies up to about 100 kHz. Above 100 kHz induced signal in the probes results in increases in potential drop and phase angle. The induced signal is reproducible and therefore may be related to the crack mouth opening displacement

  1. An improved potential drop method for measuring and monitoring defects in metallic structures

    International Nuclear Information System (INIS)

    Oppermann, W.; Keller, H.P.

    1993-01-01

    In the developed form described the direct current potential drop method is a reliable and relatively accurate procedure for the measuring and surveillance of surface cracks in metallic materials. There are also significant possibilities in practice of surveying cracks on the inaccessible side of the structure. The basis for the improvement in accuracy, in particular for short cracks, is firstly an improved measuring technique and secondly calibration curves determined using an electrolytic tank. Practical experience gained in conventional plants is to date positive. The opportunity exists of benefitting from the advantages that would be brought about by an increased use of the potential drop method in plant surveillance. In nuclear plants specifically this would achieve a reduction in the testing personnel's exposure to radiation. (orig.)

  2. Application of the DC potential drop and the partial unloading methods to fracture mechanics tests

    International Nuclear Information System (INIS)

    Heerens, J.; Schwalbe, K.H.; Hellmann, D.; Knaack, J.; Mueller-Roos, J.

    1985-01-01

    The ability of the DC potential drop method and the partial unloading technique to measure crack growth and to detect initation of crack growth has been investigated using a number of steels and aluminium alloys. It was found that within the range of parameters investigated both of these methods can be recommended for the determination of the R-curve; however, since at small amounts of crack growth the DC potential drop method gave more consistent results it is therefore considered to be superior. The initation values J(0) of J determined by fractography were compared with J(Ic) as obtained by current practice. It was found that J(Ic) is poorly related to initation or to specific amount of crack growth. A modification of the J(Ic) procedure is proposed. Two contacting arrangements of the DC potential drop method were checked for initation detection: one indicates initation by a potential minimum (related to a J value J(min)), the other by the intersection of the R-curve with the blunting line (related to a J value J(int)). (orig.) [de

  3. Monitoring crack growth by a potential drop method

    International Nuclear Information System (INIS)

    Tomlinson, J.R.

    1978-01-01

    A theoretical model has been developed for the surface current flow and potential distribution around a surface breaking crack. This model's predictions have been confirmed in the laboratory and the method applied on site. It proved possible by careful design and rigorous testing to overcome the problems of interference in an electrically noisy environment. The principal weaknesses of the technique are that it is only capable of detecting cracks that break the accessible surface of the component, and that there may be problems with conductive bridging across the crack. On the other hand, the lack of any sophisticated probe in contact with the component makes the method suitable for high temperature use, and, being an electrical method, it is capable of continuous use. The use of a.c., as opposed to d.c., enables lower currents to be used. Given good access to the crack tip, a high sensitivity can be obtained, which enables noise rejection to be achieved with the use of a high threshold. (orig.) [de

  4. Stable Amplification and High Current Drop Bistable Switching in Supercritical GaAs Tills

    DEFF Research Database (Denmark)

    Izadpanah, S.H; Jeppsson, B; Jeppesen, Palle

    1974-01-01

    Bistable switching with current drops of 40% and switching times of 100 ps are obtained in pulsed operation of 10¿m supercritically doped n+ nn+ GaAs Transferred Electron Devices (TEDs). When CW-operated the same devices exhibit a 5-17 GHz bandwidth for the stable negative resistance.......Bistable switching with current drops of 40% and switching times of 100 ps are obtained in pulsed operation of 10¿m supercritically doped n+ nn+ GaAs Transferred Electron Devices (TEDs). When CW-operated the same devices exhibit a 5-17 GHz bandwidth for the stable negative resistance....

  5. Electron-hole drop (EHD) stability in deformation potential well

    International Nuclear Information System (INIS)

    Makarov, A.G.; Tikhodeev, S.G.

    1984-01-01

    In heterogeneously-deformed Ge the stability of electron-hole droplets (EHD) being in a potential well is considered. It is shown that the potential well effect is equivalent to the decrease of effective density of phonon EHD charge. It is pointed out that heating EHD (for example, by IR radiation), can increase the phonon droplet charge and affect its stability

  6. The effect of mining data k-means clustering toward students profile model drop out potential

    Science.gov (United States)

    Purba, Windania; Tamba, Saut; Saragih, Jepronel

    2018-04-01

    The high of student success and the low of student failure can reflect the quality of a college. One of the factors of fail students was drop out. To solve the problem, so mining data with K-means Clustering was applied. K-Means Clustering method would be implemented to clustering the drop out students potentially. Firstly the the result data would be clustering to get the information of all students condition. Based on the model taken was found that students who potentially drop out because of the unexciting students in learning, unsupported parents, diffident students and less of students behavior time. The result of process of K-Means Clustering could known that students who more potentially drop out were in Cluster 1 caused Credit Total System, Quality Total, and the lowest Grade Point Average (GPA) compared between cluster 2 and 3.

  7. Electrostatic potential profile and nonlinear current in an interacting ...

    Indian Academy of Sciences (India)

    Unknown

    Since the Poisson distribution crucially depends on charge densities ... formedon a large number of systems using semi-empirical to first-principles ... known by now that the current in these systems is a nonlinear function of the voltage and ..... the middle of the molecule and the potential drop is smaller near the interfaces.

  8. Direct comparison of unloading compliance and potential drop techniques in J-integral testing

    International Nuclear Information System (INIS)

    McGowan, J.J.; Nanstad, R.K.

    1984-01-01

    Single-specimen J-integral testing is performed commonly with the unloading compliance technique. Use of modern instrumentation techniques and powerful desktop computers have made this technique a standard. However, this testing technique is slow and tedious, with the loading rate fixed at a slow quasi-static rate. For these reasons the dc potential drop technique was investigated for crack length measurement during a J-integral test. For direct comparison, both unloading compliance and potential drop were used simultaneously during a J-integral test. The results showed good agreement between the techniques. However, the potential drop technique showed an offset in crack length due to plastic blunting processes. Taking this offset into account, J/sub Ic/ values calculated by both techniques compared well

  9. Potential Multi-Canister Overpack (MCO) Cask Drop in the K West Basin South Loadout Pit

    International Nuclear Information System (INIS)

    POWERS, T.B.

    1999-01-01

    This calculation note documents the probabilistic calculation of a potential drop of a multi-canister overpack (MCO) cask or MCO cask and immersion pail at the K West Basin south loadout pit. The calculations are in support of the cask loading system (CLS) subproject alignment of CLS equipment in the K West Basin south loadout pit

  10. Potential drop crack growth monitoring in high temperature biaxial fatigue tests

    International Nuclear Information System (INIS)

    Fitzgerald, B.P.; Krempl, E.

    1993-01-01

    The present work describes a procedure for monitoring crack growth in high temperature, biaxial, low cycle fatigue tests. The reversing DC potential drop equipment monitors smooth, tubular type 304 stainless steel specimens during fatigue testing. Electrical interference from an induction heater is filtered out by an analog filter and by using a long integration time. A Fourier smoothing algorithm and two spline interpolations process the large data set. The experimentally determined electrical potential drop is compared with the theoretical electrostatic potential that is found by solving Laplace's equation for an elliptical crack in a semi-infinite conducting medium. Since agreement between theory and experiment is good, the method can be used to measure crack growth to failure from the threshold of detectability

  11. Brownian diode: Molecular motor based on a semi-permeable Brownian particle with internal potential drop

    International Nuclear Information System (INIS)

    Plyukhin, A.V.

    2013-01-01

    A model of an autonomous isothermal Brownian motor with an internal propulsion mechanism is considered. The motor is a Brownian particle which is semi-transparent for molecules of surrounding ideal gas. Molecular passage through the particle is controlled by a potential similar to that in the transition rate theory, i.e. characterized by two stationary states with a finite energy difference separated by a potential barrier. The internal potential drop maintains the diode-like asymmetry of molecular fluxes through the particle, which results in the particle's stationary drift.

  12. Simulation of auroral current sheet equilibria and associated V-shaped potential structures

    International Nuclear Information System (INIS)

    Singh, N.; Thiemann, H.; Schunk, R.W.

    1983-01-01

    Results from numerical simulations of auroral current sheet equilibrium and associated V-shaped potential structures are presented. It is shown that with allowance for both hot magnetospheric ion and cold ionospheric ion populations, the perpendicular potential drop, assiciated with a non-neutral auroral current sheet is critically controlled by the temperature of the 'heated' ionospheric ions. The heating is caused by the wave turbulence excited by the auroral current sheet. In the presence of heated ionospheric ions, a relatively large variation in the temperature of the hot magnetospheric ion population causes a very small variation in the potential drop thetam. The perpendicular potential drop acts to produce a V-shaped double layer with multiple potential steps parallel to the magnetic field when a zero potential boundary condition is imposed at the ionospheric boundary. Outside the V-shaped potential structure, ionospheric return currents develop self-consistently

  13. Circular electrodes to reduce the current variation of OTFTs with the drop-casted semiconducting layer

    Science.gov (United States)

    Dipu Kabir, H. M.; Ahmed, Zubair; Kariyadan, Remashan; Zhang, Lining; Chan, Mansun

    2018-06-01

    Circular organic thin film transistor (OTFT) structures are proposed to reduce the impact of variable grain alignment on the drive current of the polycrystalline organic thin film transistor (OTFT). As the circular structure is planar symmetric, the orientation of the grain cannot affect the drive current of the circular OTFT. Thus, circular electrodes expected to provide a lower variation. Top-gate, bottom-contact circular and conventional OTFTs with drop-casted polycrystalline 6,13-Bis(triisopropyl-silylethynyl) (TIPS)-Pentacene organic semiconducting layer (OSC) are fabricated to verify the theoretical variation reduction. The relative standard deviation (RSD), defined as the ratio of standard deviation and the average of drive current is used as the degree of variations in different structures. According to our fabrication result, circular transistors have a significantly lower variation (20% RSD), compared to the variation of conventional OTFTs (61% RSD). His research interests include Organic Electronics, VLSI Design, Embedded System, Neural Networks, and Solid-state devices. Between July 2001 and December 2002, he was a Visiting Professor at University of California at Berkeley and the Co-director of the BSIM program. He is currently still consulting on the development of the next generation compact models. He has been actively contributing to the professional community and hold many positions. He was a Board of Governor, Chair of the Education Committee, the Chair of the Region 10 subcommittee and a Distinguished lecturer of the IEEE Electron Device Society. He has also chaired many international conferences and acting as editors for a number of technical journals. In addition, he has received many awards including the UC Regents Fellowship, Golden Keys Scholarship for Academic Excellence, SRC Inventor Recognition Award, Rockwell Research Fellowship, R&D 100 award (for the BSIM3v3 project), Distinguished Teaching Award, the Shenzhen Science and Technology

  14. Deformed potential energy of $^{263}Db$ in a generalized liquid drop model

    CERN Document Server

    Chen Bao Qiu; Zhao Yao Lin; 10.1088/0256-307X/20/11/009

    2003-01-01

    The macroscopic deformed potential energy for super-heavy nuclei /sup 263/Db, which governs the entrance and alpha decay channels, is determined within a generalized liquid drop model (GLDM). A quasi- molecular shape is assumed in the GLDM, which includes volume-, surface-, and Coulomb-energies, proximity effects, mass asymmetry, and an accurate nuclear radius. The microscopic single particle energies derived from a shell model in an axially deformed Woods- Saxon potential with a quasi-molecular shape. The shell correction is calculated by the Strutinsky method. The total deformed potential energy of a nucleus can be calculated by the macro-microscopic method as the summation of the liquid-drop energy and the Strutinsky shell correction. The theory is applied to predict the deformed potential energy of the experiment /sup 22/Ne+/sup 241/Am to /sup 263/Db* to /sup 259/Db+4 n, which was performed on the Heavy Ion Accelerator in Lanzhou. It is found that the neck in the quasi-molecular shape is responsible for t...

  15. Electrochemical noise measurements techniques and the reversing dc potential drop method applied to stress corrosion essays

    International Nuclear Information System (INIS)

    Aly, Omar Fernandes; Andrade, Arnaldo Paes de; MattarNeto, Miguel; Aoki, Idalina Vieira

    2002-01-01

    This paper aims to collect information and to discuss the electrochemical noise measurements and the reversing dc potential drop method, applied to stress corrosion essays that can be used to evaluate the nucleation and the increase of stress corrosion cracking in Alloy 600 and/or Alloy 182 specimens from Angra I Nuclear Power Plant. Therefore we will pretend to establish a standard procedure to essays to be realized on the new autoclave equipment on the Laboratorio de Eletroquimica e Corrosao do Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo - Electrochemical and Corrosion Laboratory of the Chemical Engineering Department of Polytechnical School of Sao Paulo University, Brazil. (author)

  16. Potential risk factors associated with risk for drop-out and relapse during and following withdrawal of opioid prescription medication.

    Science.gov (United States)

    Heiwe, Susanne; Lönnquist, Ingeborg; Källmén, Håkan

    2011-10-01

    Withdrawal of opioid medication in patients with chronic pain has a drop-out and relapse problem. To evaluate if depressive symptoms, anxiety and pain intensity are potential risk factors for drop-out or relapse during the withdrawal process. Further, to assess internal consistency of scales for assessment of these potential risk factors. Twenty-nine patients were included. After 2 years 28 of these were followed-up. Those with depressive symptoms at baseline had a significant risk for drop-out from the withdrawal program (odds ratio 1.37) and relapse into use of opioids at follow-up (odds ratio 1.44). Drop-outs rated depressive symptoms significantly higher before detoxification. Those who relapsed rated significantly higher for pain intensity, depressive symptoms and abstinence prior to withdrawal. All scales had high reliability. To avoid drop-out and relapse clinical practice need to screen for depressive symptoms, pain intensity, and abstinence. This article presents significant reliability of scales useful within dependency centers. They can be used to identify these risk factors for drop-out and relapse, respectively, when initiating the withdrawal process. Taking these risk factors into consideration could improve the outcome of the withdrawal process by preventing drop-out and relapse. Copyright © 2011 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

  17. Energy from streaming current and potential

    NARCIS (Netherlands)

    Olthuis, Wouter; Schippers, Bob; Eijkel, Jan C.T.; van den Berg, Albert

    2005-01-01

    It is investigated how much energy can be delivered by a streaming current source. A streaming current and subsequent streaming potential originate when double layer charge is transported by hydrodynamic flow. Theory and a network model of such a source is presented and initial experimental results

  18. Potential drops supported by ion density cavities in the dynamic response of a plasma diode to an applied field

    International Nuclear Information System (INIS)

    Bohm, M.; Torven, S.

    1990-06-01

    Experiments have shown that an applied voltage drop may either be supported by a cathode sheath or by a quasi-linear variation over the plasma lasting for several electron transit times. In the latter case an ion density cavity existed initially. An analytical model and numerical simulations are used to show that a cavity gives rise to a quasi-linear potential variation for applied voltage drops below a certain critical value. For larger values the drop concentrates to a cathode sheath. The quasi-linear profile steepens to a double layer for large cavity depths. (authors)

  19. Analysis of a potential meteorite-dropping event over the south of Spain in 2007

    Science.gov (United States)

    Madiedo, J. M.; Trigo-Rodríguez, J. M.

    2008-09-01

    Introduction Four potential meteorite-dropping events happened over Spain during 2007. All them are being carefully studied in the framework of the SPanish Meteor Network (SPMN). Due to the large range of visibility of these events, they usually appear far away from the recording stations, or in broad daylight. The later was the case of the most remarkable of these events: the diurnal bolide witnessed by thousands of people in the afternoon of May 10, at 17h57m01±5s UTC. That magnificent daylight event produced the Puerto Lápice meteorite, an eucrite with a total known weight of about 500 grams [1, 2]. Other wonderful event happened during the afternoon of March 2, 2007 at 18h51m06±1s UTC: a magnificent bolide (Fig. 1) was seen over the Pyrenees by several eyewitnesses located in Catalonia and Aragon, but also from the South of France. Unfortunately it was not recorded by SPMN stations and a very limited number of visual reports were received. Figure 1. The appearance of the March 2, 2007 bolide as drawn made by the second author and fortunate eyewitness from Sant Celoni (Barcelona). Another potential meteorite-dropping diurnal bolide was witnessed from several locations over the south of Spain on the afternoon of June 29. A sonic boom was reported by witnesses located near from the estimated impact area, in the province of Huelva (Andalusia). In some cases these also reported that the bolide generated electrophonic sounds and that the sonic boom was accompanied by vibration of objects inside their houses. However, despite several expeditions to the impact area have been made, the meteorite produced by this bolide has not been found yet. This is mainly due to the high uncertainty in the calculation of the impact point, as the region is quite unpopulated and just about a dozen of eyewitnesses could be interviewed. On the other hand, the characteristics of the vegetation that grows in the area also poses important difficulties to the search tasks. Besides, as in

  20. Evaluation of the a.c. potential drop method to determine J-crack resistance curves for a pressure vessel steel

    International Nuclear Information System (INIS)

    Gibson, G.P.

    1989-01-01

    An evaluation has been carried out of the a.c. potential drop technique for determining J-crack growth resistance curves for a pressure vessel steel. The technique involves passing an alternating current through the specimen and relating the changes in the potential drop across the crack mouth to changes in crack length occuring during the test. The factors investigated were the current and voltage probe positions, the a.c. frequency and the test temperature. In addition, by altering the heat treatment of the material, J-crack resistance curves were obtained under both contained and non-contained yielding conditions. In all situations, accurate J-R curves could be determined. (author)

  1. Electron cooling and finite potential drop in a magnetized plasma expansion

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Sanchez, M. [Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Navarro-Cavallé, J. [Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros 3, Madrid 28040 (Spain); Ahedo, E. [Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Avda. Universidad 30, Leganés 28911, Madrid (Spain)

    2015-05-15

    The steady, collisionless, slender flow of a magnetized plasma into a surrounding vacuum is considered. The ion component is modeled as mono-energetic, while electrons are assumed Maxwellian upstream. The magnetic field has a convergent-divergent geometry, and attention is restricted to its paraxial region, so that 2D and drift effects are ignored. By using the conservation of energy and magnetic moment of particles and the quasi-neutrality condition, the ambipolar electric field and the distribution functions of both species are calculated self-consistently, paying attention to the existence of effective potential barriers associated to magnetic mirroring. The solution is used to find the total potential drop for a set of upstream conditions, plus the axial evolution of various moments of interest (density, temperatures, and heat fluxes). The results illuminate the behavior of magnetic nozzles, plasma jets, and other configurations of interest, showing, in particular, in the divergent plasma the collisionless cooling of electrons, and the generation of collisionless electron heat fluxes.

  2. Calculation of the force acting on a drop in a nonuniform flow of a current-supporting fluid

    International Nuclear Information System (INIS)

    Korovin, V.M.

    1993-01-01

    In the context of wide use of intense electric currents in various technological process, it is of practical interest to investigate the characteristics of the force action of electromagnetic fields on a variety of inclusions - solid particles, drops, gas bubbles - suspended in current-supporting fluids. In the available studies one treats the simplest case, in which the vortical component of the electromagnetic forces, generated by the interaction of the current with the internal magnetic field, is nonvanishing only in small vicinities near these inclusions, and therefore these electromagnetic forces do not generate global motion of the homogeneous current-supporting fluid. In practice, in most cases the vortical component of electromagnetic forces plays a substantial role in the whole operating region of the technological device, and the motion of the current-supporting fluid is created specifically by electromagnetic forces. In the case of a varying electromagnetic field the forces acting on particles are located in the conducting fluid, moving under the field action, were calculated by Korovim (Korovim, V. M., open-quotes The calculation of forces acting on suspended particles during the flow of a conducting fluid in a varying electromagnetic field,close quotes Magn. Gidrodin, No. 1 95-102 (1991)). In the present study the authors generalize the method suggested by Korovin for calculating forces applied to both drops and particles and gas bubbles suspended in the gradient flow of a fluid moving under the action of a constant electromagnetic field. 6 refs

  3. Spume Drops: Their Potential Role in Air-Sea Gas Exchange

    Science.gov (United States)

    Monahan, Edward C.; Staniec, Allison; Vlahos, Penny

    2017-12-01

    After summarizing the time scales defining the change of the physical properties of spume and other droplets cast up from the sea surface, the time scales governing drop-atmosphere gas exchange are compared. Following a broad review of the spume drop production functions described in the literature, a subset of these functions is selected via objective criteria, to represent typical, upper bound, and lower bound production functions. Three complementary mechanisms driving spume-atmosphere gas exchange are described, and one is then used to estimate the relative importance, over a broad range of wind speeds, of this spume drop mechanism compared to the conventional, diffusional, sea surface mechanism in air-sea gas exchange. While remaining uncertainties in the wind dependence of the spume drop production flux, and in the immediate sea surface gas flux, preclude a definitive conclusion, the findings of this study strongly suggest that, at high wind speeds (>20 m s-1 for dimethyl sulfide and >30 m s-1 for gases such a carbon dioxide), spume drops do make a significant contribution to air-sea gas exchange.Plain Language SummaryThis paper evaluates the existing spume drop generation functions available to date and selects a reasonable upper, lower and mid range function that are reasonable for use in air sea exchange models. Based on these the contribution of spume drops to overall air sea gas exchange at different wind speeds is then evaluated to determine the % contribution of spume. Generally below 20ms-1 spume drops contribute <1% of gas exchange but may account for a significant amount of gas exchange at higher wind speeds.

  4. Critical potentials, leptons, and weak currents

    International Nuclear Information System (INIS)

    Smith, P.F.; Lewin, J.D.

    1977-12-01

    A theoretical study is made of the interaction of very strong localised electromagnetic potentials with charged leptons, and with the vacuum state. The principal objective is to investigate the phenomena which occur when the potential reaches or exceeds the critical value at which bound levels are drawn into the lower continuum. The behaviour of bound and continuum solutions of the Dirac equation for the specific model of a short range potential well in an arbitrarily large bounded volume is examined in detail. Vacuum polarisation effects are computed by summation over the infinite set of single particle levels, and special attention is given to the behaviour of the overall charge distribution as the potential strength increases through the critical value. The most significant features of the results are (a) the formation of highly localised electron or muon bound states, (b) similar critical potential strengths for electrons and muons, and (c) redefinition of the vacuum by one charge unit at the critical potential. These features are analogous to some properties of leptonic and hadronic weak currents, and the hypothesis is proposed that strong short range potentials may provide a possible mediating mechanism for the weak interaction and also a lepton confinement mechanism within the structure of hadrons. (author)

  5. Impedance and electrically evoked compound action potential (ECAP drop within 24 hours after cochlear implantation.

    Directory of Open Access Journals (Sweden)

    Joshua Kuang-Chao Chen

    Full Text Available Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (≈ 2.5 cm and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001. There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes

  6. An improved potential drop method for measuring and monitoring defects in structures

    International Nuclear Information System (INIS)

    Oppermann, W.; Keller, H.P.

    1991-01-01

    In its advanced form, the direct-current potential probe measuring technique is a reliable and relatively exact procedure for measuring and monitoring surface defects. In addition, there is the possibility - important for practical purposes - of measuring cracks at the inaccessible side of a component part. The improved accuracy, in particular with regard to short defects, is based on advanced measuring techniques and calibration curves determined at the electrolytical tank. (orig./DG) [de

  7. Acceptability and Potential Effectiveness of a Foot Drop Stimulator in Children and Adolescents with Cerebral Palsy

    Science.gov (United States)

    Prosser, Laura A.; Curatalo, Lindsey A.; Alter, Katharine E.; Damiano, Diane L.

    2012-01-01

    Aim: Ankle-foot orthoses are the standard of care for foot drop in cerebral palsy (CP), but may overly constrain ankle movement and limit function in those with mild CP. Functional electrical stimulation (FES) may be a less restrictive and more effective alternative, but has rarely been used in CP. The primary objective of this study was to…

  8. Obesity: Current and Potential Pharmacotherapeutics and Targets

    Science.gov (United States)

    Narayanaswami, Vidya; Dwoskin, Linda P.

    2016-01-01

    Obesity is a global epidemic that contributes to a number of health complications including cardiovascular disease, type 2 diabetes, cancer and neuropsychiatric disorders. Pharmacotherapeutic strategies to treat obesity are urgently needed. Research over the past two decades has increased substantially our knowledge of central and peripheral mechanisms underlying homeostatic energy balance. Homeostatic mechanisms involve multiple components including neuronal circuits, some originating in hypothalamus and brain stem, as well as peripherally-derived satiety, hunger and adiposity signals that modulate neural activity and regulate eating behavior. Dysregulation of one or more of these homeostatic components results in obesity. Coincident with obesity, reward mechanisms that regulate hedonic aspects of food intake override the homeostatic regulation of eating. In addition to functional interactions between homeostatic and reward systems in the regulation of food intake, homeostatic signals have the ability to alter vulnerability to drug abuse. Regarding the treatment of obesity, pharmacological monotherapies primarily focus on a single protein target. FDA-approved monotherapy options include phentermine (Adipex-P®), orlistat (Xenical®), lorcaserin (Belviq®) and liraglutide (Saxenda®). However, monotherapies have limited efficacy, in part due to the recruitment of alternate and counter-regulatory pathways. Consequently, a multi-target approach may provide greater benefit. Recently, two combination products have been approved by the FDA to treat obesity, including phentermine/topiramate (Qsymia®) and naltrexone/bupropion (Contrave®). The current review provides an overview of homeostatic and reward mechanisms that regulate energy balance, potential therapeutic targets for obesity and current treatment options, including some candidate therapeutics in clinical development. Finally, challenges in anti-obesity drug development are discussed. PMID:27773782

  9. Current-potential characteristics of electrochemical systems

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, Vincent S. [Univ. of California, Berkeley, CA (United States)

    1993-07-01

    This dissertation contains investigations in three distinct areas. Chapters 1 and 2 provide an analysis of the effects of electromagnetic phenomena during the initial stages of cell discharge. Chapter 1 includes the solution to Maxwell`s equations for the penetration of the axial component of an electric field into an infinitely long cylindrical conductor. Chapter 2 contains the analysis of the conductor included in a radial circuit. Chapter 3 provides a complete description of the equations that describe the growth of an oxide film. A finite difference program was written to solve the equations. The system investigated is the iron/iron oxide in a basic, aqueous solution. Chapters 4 and 5 include the experimental attempts for replacing formaldehyde with an innocuous reducing agent for electroless deposition. In chapter 4, current-versus-voltage curves are provided for a sodium thiosulfate bath in the presence of a copper disk electrode. Also provided are the cathodic polarization curves of a copper/EDTA bath in the presence of a copper electrode. Chapter 5 contains the experimental results of work done with sodium hypophosphite as a reducing agent. Mixed-potential-versus-time curves for solutions containing various combinations of copper sulfate, nickel chloride, and hypophosphite in the presence of a palladium disk electrode provide an indication of the reducing power of the solutions.

  10. A GCM study of organic matter in marine aerosol and its potential contribution to cloud drop activation

    Directory of Open Access Journals (Sweden)

    G. J. Roelofs

    2008-02-01

    Full Text Available With the global aerosol-climate model ECHAM5-HAM we investigate the potential influence of organic aerosol originating from the ocean on aerosol mass and chemical composition and the droplet concentration and size of marine clouds. We present sensitivity simulations in which the uptake of organic matter in the marine aerosol is prescribed for each aerosol mode with varying organic mass and mixing state, and with a geographical distribution and seasonality similar to the oceanic emission of dimethyl sulfide. Measurements of aerosol mass, aerosol chemical composition and cloud drop effective radius are used to assess the representativity of the model initializations. Good agreement with the measurements is obtained when organic matter is added to the Aitken, accumulation and coarse modes simultaneously. Representing marine organics in the model leads to higher cloud drop number concentrations and thus smaller cloud drop effective radii, and this improves the agreement with measurements. The mixing state of the organics and the other aerosol matter, i.e. internal or external depending on the formation process of aerosol organics, is an important factor for this. We estimate that globally about 75 Tg C yr−1 of organic matter from marine origin enters the aerosol phase, with comparable contributions from primary emissions and secondary organic aerosol formation.

  11. Study of Hot Salt Stress Corrosion Crack Initiation of Alloy IMI 834 by using DC Potential Drop Method

    Energy Technology Data Exchange (ETDEWEB)

    Pustode, Mangesh D. [Bharat Forge Ltd., Pune (India); Dewangan, Bhupendra [Tata Steel, Jamshedpur (India); Raja, V. S. [Indian Institute of Technology Bombay, Mumbai (India); Paulose, Neeta; Babu, Narendra [Gas Turbine Research Establishment (GTRE), Bangalore (India)

    2016-10-15

    DC potential drop technique was employed during the slow strain rate tests to study the hot salt stress corrosion crack (HSSCC) initiation at 300 and 400 ℃. Threshold stresses for HSSCC initiation were found to about 88 % of the yield strength at both temperatures, but the time from crack initiation to final failure (Δtscc) decreased significantly with temperature, which reflects larger tendency for brittle fracture and secondary cracking. The brittle fracture features consisted of transgranular cracking through the primary α grain and discontinuous faceted cracking through the transformed β grains.

  12. Electric Mars: A Large Trans-Terminator Electric Potential Drop on Closed Magnetic Field Lines Above Utopia Planitia

    Science.gov (United States)

    Collinson, Glyn; Mitchell, David; Xu, Shaosui; Glocer, Alex; Grebowsky, Joseph; Hara, Takuya; Lillis, Robert; Espley, Jared; Mazelle, Christian; Sauvaud, Jean-Andre

    2017-01-01

    Abstract Parallel electric fields and their associated electric potential structures play a crucial role inionospheric-magnetospheric interactions at any planet. Although there is abundant evidence that parallel electric fields play key roles in Martian ionospheric outflow and auroral electron acceleration, the fields themselves are challenging to directly measure due to their relatively weak nature. Using measurements by the Solar Wind Electron Analyzer instrument aboard the NASA Mars Atmosphere and Volatile EvolutioN(MAVEN) Mars Scout, we present the discovery and measurement of a substantial (Phi) Mars 7.7 +/-0.6 V) parallel electric potential drop on closed magnetic field lines spanning the terminator from day to night above the great impact basin of Utopia Planitia, a region largely free of crustal magnetic fields. A survey of the previous 26 orbits passing over a range of longitudes revealed similar signatures on seven orbits, with a mean potential drop (Phi) Mars of 10.9 +/- 0.8 V, suggestive that although trans-terminator electric fields of comparable strength are not ubiquitous, they may be common, at least at these northerly latitudes.

  13. Electric Mars: A large trans-terminator electric potential drop on closed magnetic field lines above Utopia Planitia

    Science.gov (United States)

    Collinson, Glyn; Mitchell, David; Xu, Shaosui; Glocer, Alex; Grebowsky, Joseph; Hara, Takuya; Lillis, Robert; Espley, Jared; Mazelle, Christian; Sauvaud, Jean-André; Fedorov, Andrey; Liemohn, Mike; Andersson, Laila; Jakosky, Bruce

    2017-02-01

    Parallel electric fields and their associated electric potential structures play a crucial role in ionospheric-magnetospheric interactions at any planet. Although there is abundant evidence that parallel electric fields play key roles in Martian ionospheric outflow and auroral electron acceleration, the fields themselves are challenging to directly measure due to their relatively weak nature. Using measurements by the Solar Wind Electron Analyzer instrument aboard the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) Mars Scout, we present the discovery and measurement of a substantial (ΦMars=7.7 ± 0.6 V) parallel electric potential drop on closed magnetic field lines spanning the terminator from day to night above the great impact basin of Utopia Planitia, a region largely free of crustal magnetic fields. A survey of the previous 26 orbits passing over a range of longitudes revealed similar signatures on seven orbits, with a mean potential drop (ΦMars) of 10.9 ± 0.8 V, suggestive that although trans-terminator electric fields of comparable strength are not ubiquitous, they may be common, at least at these northerly latitudes.

  14. Potential suitable areas of giant ground sloths dropped before its extinction in South America

    DEFF Research Database (Denmark)

    Lima-Ribeiro, Matheus Souza; Varela, Sara; Nogues, David Bravo

    2012-01-01

    of the climate preferences through time for the two species and modeled their potential distributions at last glacial maximum (LGM, 21 ky BP) and mid-Holocene (6 ky BP) using Bioclimatic Envelope Modeling (BEM), fossil records and paleoclimatic simulations. The model predictions showed a drastic reduction......Here we analyze the effects that climatic changes through last ice age had on the potential distributions and extinction risk dynamics of two extinct species of South American giant ground sloths, Eremotherium laurillardi and Megatherium americanum. We tested the assumption of stability...

  15. Stable isotope enrichment: Current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1992-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities

  16. Stable isotope enrichment - current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1993-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL. This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities. (orig.)

  17. Online fatigue crack growth monitoring with clip gauge and direct current potential drop

    OpenAIRE

    De Tender, Steven; Micone, Nahuel; De Waele, Wim

    2016-01-01

    Fatigue is a well-known failure phenomenon which has been and still is extensively studied. Often structures are designed according to the safe-life principle so no crack initiation occurs. Nowadays there is a high emphasis on cost-efficiency, and one might rather opt for a fail-safe design. Therefore a certain amount of crack growth can be allowed in structures, but then a good knowledge of stresses and related crack growth rates is needed. To this end, extensive studies are done to obtain a...

  18. Current and potential treatment options for hyperphosphatemia.

    Science.gov (United States)

    Carfagna, Fabio; Del Vecchio, Lucia; Pontoriero, Giuseppe; Locatelli, Francesco

    2018-05-21

    Hyperphosphatemia is common in late stages of chronic kidney disease and is often associated with elevated parathormone levels, abnormal bone mineralization, extra-osseous calcification, and increased risk of cardiovascular events and death. Several classes of oral phosphate binders are available to help control plasma phosphorus levels. Although effective at lowering serum phosphorus, they all have safety, tolerability, and compliance issues that need to be considered when selecting which one to use. Areas covered: This paper reviews the most established treatment options for hyperphosphatemia, in patients with chronic kidney disease, focusing on the new inhibitors of active phosphate absorption. Expert opinion: The prevention and the treatment of hyperphosphatemia is today far to be satisfactory. Nonetheless, an extending range of phosphate binders are now available. Aluminum has potentially serious toxic risks. Calcium-based binders are very effective but can lead to hypercalcemia and/or positive calcium balance and progression of cardiovascular calcification. No long-term data are available for the new calcium acetate/magnesium combination product. Lanthanum is an effective phosphate binder, and long-term effects of tissue deposition seem clinically irrelevant. Sevelamer, appear to have profiles that would lead to pleiotropic effects and reduced progression of vascular calcification, and the main adverse events seen with these agents are gastrointestinal. Iron has a powerful capability of binding phosphate, thus numerous preparations are available, both with and without significant systemic absorption of the iron component. The inhibitors of active intestinal phosphate transport, with their very selective mechanism of action and low pill burden seem the most interesting approach; however, do not seem at present to be effective alone, in reducing serum phosphorus levels.

  19. Drop Tower Physics

    Science.gov (United States)

    Dittrich, William A.

    2014-01-01

    The drop towers of yesteryear were used to make lead shot for muskets, as described in "The Physics Teacher" in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at…

  20. Application of the potential-drop method to measurements of hydrogen-induced sub-critical crack growth in zirconium-2.5 wt% niobium

    International Nuclear Information System (INIS)

    Simpson, L.A.; Clarke, C.F.

    1977-10-01

    Adaptation of the potential-drop method of crack-following to the problem of hydrogen-induced sub-critical crack growth in Zr-2.5% Nb is described. Reasons for non-linearity in the calibration of crack extension against potential drop in compact tension specimens are discussed. It is shown that despite non-linearities, careful comparison of fractographic features with the potential-drop record can lead to a continuous plot of crack velocity against time or stress intensity factor. Procedures for correcting data through temperature and load changes are also described. The application of the technique to studies of the mechanism of hydrogen crack growth is illustrated with several examples. (author)

  1. Current Drive in a Ponderomotive Potential with Sign Reversal

    Energy Technology Data Exchange (ETDEWEB)

    N.J. Fisch; J.M. Rax; I.Y. Dodin

    2003-07-30

    Noninductive current drive can be accomplished through ponderomotive forces with high efficiency when the potential changes sign over the interaction region. The effect can practiced upon both ions and electrons. The current drive efficiencies, in principle, might be higher than those possible with conventional radio-frequency current-drive techniques, since different considerations come into play.

  2. Current Drive in a Ponderomotive Potential with Sign Reversal

    International Nuclear Information System (INIS)

    Fisch, N.J.; Rax, J.M.; Dodin, I.Y.

    2003-01-01

    Noninductive current drive can be accomplished through ponderomotive forces with high efficiency when the potential changes sign over the interaction region. The effect can practiced upon both ions and electrons. The current drive efficiencies, in principle, might be higher than those possible with conventional radio-frequency current-drive techniques, since different considerations come into play

  3. Poststroke Muscle Architectural Parameters of the Tibialis Anterior and the Potential Implications for Rehabilitation of Foot Drop

    Directory of Open Access Journals (Sweden)

    John W. Ramsay

    2014-01-01

    Full Text Available Poststroke dorsiflexor weakness and paretic limb foot drop increase the risk of stumbling and falling and decrease overall functional mobility. It is of interest whether dorsiflexor muscle weakness is primarily neurological in origin or whether morphological differences also contribute to the impairment. Ten poststroke hemiparetic individuals were imaged bilaterally using noninvasive medical imaging techniques. Magnetic resonance imaging was used to identify changes in tibialis anterior muscle volume and muscle belly length. Ultrasonography was used to measure fascicle length and pennation angle in a neutral position. We found no clinically meaningful bilateral differences in any architectural parameter across all subjects, which indicates that these subjects have the muscular capacity to dorsiflex their foot. Therefore, poststroke dorsiflexor weakness is primarily neural in origin and likely due to muscle activation failure or increased spasticity of the plantar flexors. The current finding suggests that electrical stimulation methods or additional neuromuscular retraining may be more beneficial than targeting muscle strength (i.e., increasing muscle mass.

  4. Measurements of the large-scale direct-current Earth potential and possible implications for the geomagnetic dynamo.

    Science.gov (United States)

    1985-07-05

    The magnitude of the large-scale direct-current earth potential was measured on a section of a recently laid transatlantic telecommunications cable. Analysis of the data acquired on the 4476-kilometer cable yielded a mean direct-current potential drop of less than about 0.072 +/- 0.050 millivolts per kilometer. Interpreted in terms of a generation of the potential by the earth's geodynamo, such a small value of the mean potential implies that the toroidal and poloidal magnetic fields of the dynamo are approximately equal at the core-mantle boundary.

  5. Development of ultrasonically levitated drops as microreactors for study of enzyme kinetics and potential as a universal portable analysis system

    Science.gov (United States)

    Scheeline, A.; Pierre, Z.; Field, C. R.; Ginsberg, M. D.

    2009-05-01

    Development of microfluidics has focused on carrying out chemical synthesis and analysis in ever-smaller volumes of solution. In most cases, flow systems are made of either quartz, glass, or an easily moldable polymer such as polydimethylsiloxane (Whitesides 2006). As the system shrinks, the ratio of surface area to volume increases. For studies of either free radical chemistry or protein chemistry, this is undesirable. Proteins stick to surfaces, biofilms grow on surfaces, and radicals annihilate on walls (Lewis et al. 2006). Thus, under those circumstances where small amounts of reactants must be employed, typical microfluidic systems are incompatible with the chemistry one wishes to study. We have developed an alternative approach. We use ultrasonically levitated microliter drops as well mixed microreactors. Depending on whether capillaries (to form the drop) and electrochemical sensors are in contact with the drop or whether there are no contacting solids, the ratio of solid surface area to volume is low or zero. The only interface seen by reactants is a liquid/air interface (or, more generally, liquid/gas, as any gas may be used to support the drop). While drop levitation has been reported since at least the 1940's, we are the second group to carry out enzyme reactions in levitated drops, (Weis; Nardozzi 2005) and have fabricated the lowest power levitator in the literature (Field; Scheeline 2007). The low consumption aspects of ordinary microfluidics combine with a contact-free determination cell (the levitated drop) that ensures against cross-contamination, minimizes the likelihood of biofilm formation, and is robust to changes in temperature and humidity (Lide 1992). We report kinetics measurements in levitated drops and explain how outgrowths of these accomplishments will lead to portable chemistry/biology laboratories well suited to detection of a wide range of chemical and biological agents in the asymmetric battlefield environment.

  6. Effects of a potential drop of a shipping cask, a waste container, and a bare fuel assembly during waste-handling operations

    International Nuclear Information System (INIS)

    Wu, C.L.; Lee, J.; Lu, D.L.; Jardine, L.J.

    1991-12-01

    This study investigates the effects of potential drops of a typical shipping cask, waste container, and bare fuel assembly during waste-handling operations at the prospective Yucca Mountain Repository. The waste-handling process (one stage, no consolidation configuration) is examined to estimate the maximum loads imposed on typical casks and containers as they are handled by various pieces of equipment during waste-handling operations. Maximum potential drop heights for casks and containers are also evaluated for different operations. A nonlinear finite-element model is employed to represent a hybrid spent fuel container subject to drop heights of up to 30 ft onto a reinforced concrete floor. The impact stress, strain, and deformation are calculated, and compared to the failure criteria to estimate the limiting (maximum permissible) drop height for the waste container. A typical Westinghouse 17 x 17 PWR fuel assembly is analyzed by a simplified model to estimate the energy absorption by various parts of the fuel assembly during a 30 ft drop, and to determine the amount of kinetic energy in a fuel pin at impact. A nonlinear finite-element analysis of an individual fuel pin is also performed to estimate the amount of fuel pellet fracture due to impact. This work was completed on May 1990

  7. Current drive in a ponderomotive potential with sign reversal

    International Nuclear Information System (INIS)

    Fisch, N.J.; Dodin, I.Y.; Rax, J.M.

    2003-01-01

    Noninductive current drive can be accomplished through ponderomotive forces with high efficiency when the potential changes sign over the interaction region. The effect, which operates somewhat like a Maxwell demon, can be practiced upon both ions and electrons. The current-drive efficiencies, in principle, might be higher than those possible with conventional rf current-drive techniques. It remains, however, for us to identify how the effect might be implemented in a magnetic fusion device in a practical manner

  8. Single cell wound generates electric current circuit and cell membrane potential variations that requires calcium influx.

    Science.gov (United States)

    Luxardi, Guillaume; Reid, Brian; Maillard, Pauline; Zhao, Min

    2014-07-24

    Breaching of the cell membrane is one of the earliest and most common causes of cell injury, tissue damage, and disease. If the compromise in cell membrane is not repaired quickly, irreversible cell damage, cell death and defective organ functions will result. It is therefore fundamentally important to efficiently repair damage to the cell membrane. While the molecular aspects of single cell wound healing are starting to be deciphered, its bio-physical counterpart has been poorly investigated. Using Xenopus laevis oocytes as a model for single cell wound healing, we describe the temporal and spatial dynamics of the wound electric current circuitry and the temporal dynamics of cell membrane potential variation. In addition, we show the role of calcium influx in controlling electric current circuitry and cell membrane potential variations. (i) Upon wounding a single cell: an inward electric current appears at the wound center while an outward electric current is observed at its sides, illustrating the wound electric current circuitry; the cell membrane is depolarized; calcium flows into the cell. (ii) During cell membrane re-sealing: the wound center current density is maintained for a few minutes before decreasing; the cell membrane gradually re-polarizes; calcium flow into the cell drops. (iii) In conclusion, calcium influx is required for the formation and maintenance of the wound electric current circuitry, for cell membrane re-polarization and for wound healing.

  9. Uncertainty Analysis of the Results of Potential Cask Drops in the K West Basin South Loadout Pit

    International Nuclear Information System (INIS)

    LEW, B.S.

    1999-01-01

    If a cask and Multi-Canister Overpack (MCO) were to be dropped, the analysis established possible initial volumetric flow rates. The results of the uncertainty analysis demonstrated that even if a cask and MCO were to be dropped the possible initial volumetric flow rate through the opened floor/wall joint would be small. There is a 95% confidence (probability of 0.95) that the initial volumetric flow rate would be smaller than 411 gpm and a 99% confidence (probability of 0.99) that it would be smaller than 916 gpm

  10. Action potential propagation: ion current or intramembrane electric field?

    Science.gov (United States)

    Martí, Albert; Pérez, Juan J; Madrenas, Jordi

    2018-01-01

    The established action potential propagation mechanisms do not satisfactorily explain propagation on myelinated axons given the current knowledge of biological channels and membranes. The flow across ion channels presents two possible effects: the electric potential variations across the lipid bilayers (action potential) and the propagation of an electric field through the membrane inner part. The proposed mechanism is based on intra-membrane electric field propagation, this propagation can explain the action potential saltatory propagation and its constant delay independent of distance between Ranvier nodes in myelinated axons.

  11. Potentiostatic current and galvanostatic potential oscillations during electrodeposition of cadmium.

    Science.gov (United States)

    López-Sauri, D A; Veleva, L; Pérez-Ángel, G

    2015-09-14

    Cathodic current and potential oscillations were observed during electrodeposition of cadmium from a cyanide electrolyte on a vertical platinum electrode, in potentiostatic and galvanostatic experiments. Electrochemical impedance spectroscopy experiments revealed a region of negative real impedance in a range of non-zero frequencies, in the second descending branch with a positive slope of the N-shape current-potential curve. This kind of dynamical behaviour is characteristic of the HN-NDR oscillators (oscillators with the N-Shape current-potential curve and hidden negative differential resistance). The oscillations could be mainly attributed to the changes in the real active cathodic area, due to the adsorption of hydrogen molecules and their detachment from the surface. The instabilities of the electrochemical processes were characterized by time series, Fast Fourier Transforms and 2-D phase portraits showing quasi-periodic oscillations.

  12. Currents along the Tsitsikamma coast, South Africa, and potential ...

    African Journals Online (AJOL)

    Potential net monthly displacements calculated for three depths (5m, 23m and 31m) indicate that passive, neutrally buoyant biological material (e.g. squid ... Wind-driven coastal upwelling, prevalent during the summer, causes the surface layer of the coastal counter-current to flow offshore for several days, resulting in ...

  13. General Potential-Current Model and Validation for Electrocoagulation

    International Nuclear Information System (INIS)

    Dubrawski, Kristian L.; Du, Codey; Mohseni, Madjid

    2014-01-01

    A model relating potential and current in continuous parallel plate iron electrocoagulation (EC) was developed for application in drinking water treatment. The general model can be applied to any EC parallel plate system relying only on geometric and tabulated input variables without the need of system-specific experimentally derived constants. For the theoretical model, the anode and cathode were vertically divided into n equipotential segments in a single pass, upflow, and adiabatic EC reactor. Potential and energy balances were simultaneously solved at each vertical segment, which included the contribution of ionic concentrations, solution temperature and conductivity, cathodic hydrogen flux, and gas/liquid ratio. We experimentally validated the numerical model with a vertical upflow EC reactor using a 24 cm height 99.99% pure iron anode divided into twelve 2 cm segments. Individual experimental currents from each segment were summed to determine total current, and compared with the theoretically derived value. Several key variables were studied to determine their impact on model accuracy: solute type, solute concentration, current density, flow rate, inter-electrode gap, and electrode surface condition. Model results were in good agreement with experimental values at cell potentials of 2-20 V (corresponding to a current density range of approximately 50-800 A/m 2 ), with mean relative deviation of 9% for low flow rate, narrow electrode gap, polished electrodes, and 150 mg/L NaCl. Highest deviation occurred with a large electrode gap, unpolished electrodes, and Na 2 SO 4 electrolyte, due to parasitic H 2 O oxidation and less than unity current efficiency. This is the first general model which can be applied to any parallel plate EC system for accurate electrochemical voltage or current prediction

  14. Drop trampoline

    Science.gov (United States)

    Chantelot, Pierre; Coux, Martin; Clanet, Christophe; Quere, David

    2017-11-01

    Superhydrophobic substrates inspired from the lotus leaf have the ability to reflect impacting water drops. They do so very efficiently and contact lasts typically 10 ms for millimetric droplets. Yet unlike a lotus leaf most synthetic substrates are rigid. Focusing on the interplay between substrate flexibility and liquid repellency might allow us to understand the dynamic properties of natural surfaces. We perform liquid marbles impacts at velocity V onto thin ( 0.01 mm) stretched circular PDMS membranes. We obtain contact time reductions of up to 70%. The bouncing mechanism is drastically modified compared to that on a rigid substrate: the marble leaves the substrate while it is still spread in a disk shape as it is kicked upwards by the membrane. We show that the bouncing is controlled by an interplay between the dynamics of the drop and the membrane.

  15. Current-current correlation function in presence of chemical potential and external magnetic field

    International Nuclear Information System (INIS)

    Apresyan, E.A.

    2017-01-01

    The (2+1)-dimensional electron system was observed, where relation between the Green functions and conductivity was used. The current-current correlation function Π_μ_ν(B) for the fermion system was calculated in presence of non-quantizing magnetic field B, chemical potential η and gap m. From this function it is possible to obtain the equation for polarization operator calculated without the magnetic field. The result is also applicable for graphene

  16. Mouse ES cells have a potential to differentiate into odontoblast-like cells using hanging drop method.

    Science.gov (United States)

    Kawai, R; Ozeki, N; Yamaguchi, H; Tanaka, T; Nakata, K; Mogi, M; Nakamura, H

    2014-05-01

    We examined whether mouse embryonic stem (ES) cells can differentiate into odontoblast-like cells without epithelial-mesenchymal interaction. Cells were cultured by the 'hanging drop' method using a collagen type-I scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4). Expression of odontoblast-related mRNA and protein, and cell proliferation were performed by reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence staining and WST-1 assay, respectively. Cells potently expressed odontoblast-related cell marker mRNAs following induction of odontoblastic differentiation. Dentin sialophosphoprotein, a marker of mature odontoblasts, was strongly expressed in differentiated ES cells. The cells also acquired an odontoblast-like functional phenotype, as evidenced by the appearance of alkaline phosphatase activity and calcification. The cell-surface expression of α2, α6, αV and αVβ3 integrin proteins was rapidly upregulated in differentiated cells. Finally, anti-α2 integrin antibody suppressed the expression of odontoblastic markers in cells grown using this culture system, suggesting that α2 integrin expression in ES cells triggers their differentiation into odontoblast-like cells. Mouse ES cells cultured by the 'hanging drop' method are able to differentiate into cells with odontoblast-specific physiological functions and cell-surface integrin protein expression. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Theory of magnetostriction of electron-hole drops in Ge

    International Nuclear Information System (INIS)

    Markiewicz, R.S.

    1978-01-01

    A large mass of electron-hole liquid (γ drop) formed in a strain-induced potential well in Ge is known to distort its shape significantly in a magnetic field B > or approx. = 1 kG. It is shown in this paper that the shape change can be understood in detail as due to a ''recombination current'' of electron-hole pairs needed to replace those pairs which recombine in the drop volume. The Lorentz force deflects this current and produces a macroscopic dipole current loop inside the drop. The drop then changes shape to minimize its total energy, including magnetic, strain, and surface energies. While the drop usually flattens along the field direction, both para- and diamagnetic effects (elongated drops) are found to be possible, depending on excitation conditions, in accord with experiment. Similar effects are predicted to occur in small drops in unstrained Ge. This paper presents a magnetohydrodynamic theory of the magnetostriction which takes into account density variations which occur in the strain well and in high magnetic fields. A simpler theory is given for the special case in which the drop may be considered incompressible (small drops and moderate fields). Effects of carrier mass anisotropy and fluid viscosity are taken into consideration

  18. Dropped Ceiling

    OpenAIRE

    Tabet, Rayyane

    2012-01-01

    On December 2nd 1950 the first drop of Saudi oil arrived to Lebanon via the newly constructed Trans-Arabian Pipeline, the world's longest pipeline and the largest American private investment in a foreign land. The 30inch wide structure which spanned 1213 kilometers passing through Saudi Arabia, Jordan, and Syria to end in Lebanon had required 3 years of planning and surveying, 2 years of installation, the fabrication of 256,000 tons of steel tubes, the employment of 30,000 workers, the ratifi...

  19. N-Acetylcarnosine sustained drug delivery eye drops to control the signs of ageless vision: Glare sensitivity, cataract amelioration and quality of vision currently available treatment for the challenging 50,000-patient population

    Directory of Open Access Journals (Sweden)

    Mark A Babizhayev

    2008-10-01

    months of treatment with N-acetylcarnosine lubricant eye drops as those with the worth pretreatment vision.Patients or other participants: The authors made a reference to electronic records of the product sales to patients who have been made the repurchase of the Can-C™ eye drops since December 2001.Intervention: Based on this analysis of recorded adjustments to inventory, various parameters were analyzed during the continued repurchase behavior program, including testimonials from buyers. With these figures, researchers judged on the patients’ compliance rate to self-administer NAC eye-drops.Main outcome measure and results: The ophthalmic drug showed potential for the nonsurgical treatment of age-related cataracts for participants after controlling for age, gender and daily activities and on a combined basis of repurchases behavior reports in more than 50,000 various cohort survivors, has been demonstrated to have a high efficacy and good tolerability for prevention and treatment of visual impairment determined for the older population with relative stable pattern of causes for blindness and visual impairment. The mechanisms of prevention and reversal of cataracts with NAC ophthalmic drug are considered which include prevention by the intraocular released carnosine of free-radical-induced inactivation of proprietary lens antioxidant enzymes (superoxide dismutase; prevention of carbohydrate and metal-catalyzed autooxidation of ascorbic acid-induced cross-linking glycation reactions to the lens proteins; transglycation properties of carnosine, allowing it to compete for the glycating agent, protecting proteins (lens crystallins against modification; universal antioxidant and scavenging activity towards lipid hydroperoxides, aldehydes and oxygen radicals; activation with L-carnosine ingredient of proteasome activity in the lens; chaperone-like disaggregating to lens crystallins activity of NAC and of its bioactivated principal carnosine. Blindness incidence increased

  20. Performance Prediction of Centrifugal Compressor for Drop-In Testing Using Low Global Warming Potential Alternative Refrigerants and Performance Test Codes

    Directory of Open Access Journals (Sweden)

    Joo Hoon Park

    2017-12-01

    Full Text Available As environmental regulations to stall global warming are strengthened around the world, studies using newly developed low global warming potential (GWP alternative refrigerants are increasing. In this study, substitute refrigerants, R-1234ze (E and R-1233zd (E, were used in the centrifugal compressor of an R-134a 2-stage centrifugal chiller with a fixed rotational speed. Performance predictions and thermodynamic analyses of the centrifugal compressor for drop-in testing were performed. A performance prediction method based on the existing ASME PTC-10 performance test code was proposed. The proposed method yielded the expected operating area and operating point of the centrifugal compressor with alternative refrigerants. The thermodynamic performance of the first and second stages of the centrifugal compressor was calculated as the polytropic state. To verify the suitability of the proposed method, the drop-in test results of the two alternative refrigerants were compared. The predicted operating range based on the permissible deviation of ASME PTC-10 confirmed that the temperature difference was very small at the same efficiency. Because the drop-in test of R-1234ze (E was performed within the expected operating range, the centrifugal compressor using R-1234ze (E is considered well predicted. However, the predictions of the operating point and operating range of R-1233zd (E were lower than those of the drop-in test. The proposed performance prediction method will assist in understanding thermodynamic performance at the expected operating point and operating area of a centrifugal compressor using alternative gases based on limited design and structure information.

  1. Conversion disorder: current problems and potential solutions for DSM-5.

    Science.gov (United States)

    Stone, Jon; LaFrance, W Curt; Brown, Richard; Spiegel, David; Levenson, James L; Sharpe, Michael

    2011-12-01

    Conversion disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) describes neurological symptoms, including weakness, numbness and events resembling epilepsy or syncope, which can be positively identified as not being due to recognised neurological disease. This review combines perspectives from psychiatry, psychology and neurology to identify and discuss key problems with the current diagnostic DSM-IV criteria for conversion disorder and to make the following proposals for DSM-5: (a) abandoning the label "conversion disorder" and replacing it with an alternative term that is both theoretically neutral and potentially more acceptable to patients and practitioners; (b) relegating the requirements for "association of psychological factors" and the "exclusion of feigning" to the accompanying text; (c) adding a criterion requiring clinical findings of internal inconsistency or incongruity with recognised neurological or medical disease and altering the current 'disease exclusion' criteria to one in which the symptom must not be 'better explained' by a disease if present, (d) adding a 'cognitive symptoms' subtype. We also discuss whether conversion symptoms are better classified with other somatic symptom disorders or with dissociative disorders and how we might address the potential heterogeneity of conversion symptoms in classification. 2011 Elsevier Inc. All rights reserved.

  2. Excitation of high-frequency electromagnetic waves by energetic electrons with a loss cone distribution in a field-aligned potential drop

    Science.gov (United States)

    Fung, Shing F.; Vinas, Adolfo F.

    1994-01-01

    The electron cyclotron maser instability (CMI) driven by momentum space anisotropy (df/dp (sub perpendicular) greater than 0) has been invoked to explain many aspects, such as the modes of propagation, harmonic emissions, and the source characteristics of the auroral kilometric radiation (AKR). Recent satellite observations of AKR sources indicate that the source regions are often imbedded within the auroral acceleration region characterized by the presence of a field-aligned potential drop. In this paper we investigate the excitation of the fundamental extraordinary mode radiation due to the accelerated electrons. The momentum space distribution of these energetic electrons is modeled by a realistic upward loss cone as modified by the presence of a parallel potential drop below the observation point. On the basis of linear growth rate calculations we present the emission characteristics, such as the frequency spectrum and the emission angular distribution as functions of the plasma parameters. We will discuss the implication of our results on the generation of the AKR from the edges of the auroral density cavities.

  3. Comparison of S3-3 polar cap potential drops with the interplanetary magnetic field and models of magnetopause reconnection

    International Nuclear Information System (INIS)

    Wygant, J.R.; Torbert, R.B.; Mozer, F.S.

    1983-01-01

    Measurements of the cross polar cap electric potential, by the double probe electric field experiment aboard S3-3, from 55 orbits in the dawn-dusk plane are compared with the reconnection electric fields predicted by a variety of models, both theoretical and experimental. The purpose of these comparisons is to understand the extent to which nonreconnection contributes to the polar cap potential must be included, to determine the time response of the polar cap potential to time varying reconnection rates, and to determine the efficiency and saturation levels of the reconnection process. It is found that (1) After several hours of northward interplanetary magnetic field, the cross polar cap potential declines to progressively lower values than those after 1 hour of northward interplanetary magnetic field. This suggests that it requires several hours for the ionospheric polar cap potential to respond to the ''turning off'' of ''turning down'' of the reconnection process. (2) The decay of the polar cap potential is used to demonstrate that contirubtions to the polar cap potential not associated with the reconnection process can be limited to less than 20 kV. It is shown that contributions to the polar cap potential that scale with the dynamic pressure of the solar wind are limited to less than 1 kV. (3) The cross polar cap electric potential is best predicted by a weighted sum of contributions from interplanetary magnetic field parameter over the 4 hours previous to the measurement. The weighting functions have the form of an exponential decay 2--3 hours with the strongest weight on interplanetary parameters over the 1 hour previous to the measurement

  4. Current and potential utilisation of biomass energy in Fiji

    International Nuclear Information System (INIS)

    Prasad, S.

    1990-01-01

    Energy from biomass accounts for an average of 43% of the primary energy used in developing countries, with some countries totally dependent on biomass for all their energy needs. The most common use for biomass for energy is the provision of heat for cooking and heating; other uses include steam and electricity generation and crop and food drying. Fiji, a developing country, uses energy from wood and coconut wastes for cooking and copra drying. Bagasse from sugar mills is used to generate process steam as well as some 15 MW of electricity, for mill consumption and for sale to the national grid. Other, relatively small scale uses for biomass include the generation of steam and electricity for industry. This paper attempts to quantify the amount of biomass, in its various forms, available in Fiji and assesses the current potential utilisation of biomass for energy in Fiji. (author)

  5. N-Acetylcarnosine sustained drug delivery eye drops to control the signs of ageless vision: glare sensitivity, cataract amelioration and quality of vision currently available treatment for the challenging 50,000-patient population.

    Science.gov (United States)

    Babizhayev, Mark A; Burke, Leslie; Micans, Philip; Richer, Stuart P

    2009-01-01

    patients' compliance rate to self-administer NAC eye-drops. The ophthalmic drug showed potential for the non-surgical treatment of age-related cataracts for participants after controlling for age, gender and daily activities and on a combined basis of repurchases behavior reports in more than 50,000 various cohort survivors, has been demonstrated to have a high efficacy and good tolerability for prevention and treatment of visual impairment determined for the older population with relative stable pattern of causes for blindness and visual impairment. The mechanisms of prevention and reversal of cataracts with NAC ophthalmic drug are considered which include prevention by the intraocular released carnosine of free-radical-induced inactivation of proprietary lens antioxidant enzymes (superoxide dismutase); prevention of carbohydrate and metal-catalyzed autooxidation of ascorbic acid-induced cross-linking glycation reactions to the lens proteins; transglycation properties of carnosine, allowing it to compete for the glycating agent, protecting proteins (lens crystallins) against modification; universal antioxidant and scavenging activity towards lipid hydroperoxides, aldehydes and oxygen radicals; activation with l-carnosine ingredient of proteasome activity in the lens; chaperone-like disaggregating to lens crystallins activity of NAC and of its bioactivated principal carnosine. Blindness incidence increased with advancing age, such as cataract and glaucoma, which are by far the commonest causes of blindness in our sample and in all age groups, glaucomatous neurodegeneration can be treated with developed NAC autoinduction prodrug eye drops equipped with corneal absorption promoters. The common blinding affections presenting in developed countries such as, senile macular degeneration, hereditary chorioretinal dystrophies, diabetic retinopathy are poorly represented in our current summary of vital-statistics and will be reported inherent in next N-acetylcarnosine ophthalmic

  6. LIFELONG LEARNING THROUGH SECOND LIFE: CURRENT TRENDS, POTENTIALS AND LIMITATIONS

    Directory of Open Access Journals (Sweden)

    Nil GOKSEL-CANBEK

    2011-08-01

    Full Text Available Lifelong Learning (LLL has been a remarkable response to people-centered educational demand of 21st century. In order to provide effective formal, non-formal, and informal learning, immersive educational activities undertaken throughout life should be aimed to create a learning society in which people can experience individual and collective learning with no constrains of time or location. The concept of lifelong learning within the context of distance immersive education encompasses diverse 3D activities. The three dimensional, Web-based structured activities supported by distance learning technologies can be viewed as interactive tools which foster LLL. In this perspective, Second Life (SL can be regarded as one of the learning simulation milieus that allow learners to participate in various educational LLL activities in individual or group forms. The following paper examines how SL, taking advantage of its simulative nature and the possibility for creative interaction among participants, which are also common in games, allows the learners to participate in immersive constructivist learning activities. The article will also touch on the current uses of SL as a tool for LLL, as well as its potentials for further development according to the current trends in adult education. Further, the authors will discuss its limitations and will make suggestions towards a more complete pedagogical use.

  7. A GCM study of organic matter in marine aerosol and its potential contribution to cloud drop activation

    NARCIS (Netherlands)

    Roelofs, G.J.H.

    2007-01-01

    With the global aerosol-climate model ECHAM5-HAM we investigate the potential influence of organic aerosol originating from the ocean on aerosol mass and chemical composition and the droplet concentration and size of marine clouds. We present sensitivity simulations in which the uptake of organic

  8. Reimbursed Price of Orphan Drugs: Current Strategies and Potential Improvements.

    Science.gov (United States)

    Mincarone, Pierpaolo; Leo, Carlo Giacomo; Sabina, Saverio; Sarriá-Santamera, Antonio; Taruscio, Domenica; Serrano-Aguilar, Pedro Guillermo; Kanavos, Panos

    2017-01-01

    The pricing and reimbursement policies for pharmaceuticals are relevant to balance timely and equitable access for all patients, financial sustainability, and reward for valuable innovation. The proliferation of high-cost specialty medicines is particularly true in rare diseases (RDs) where the pricing mechanism is characterised by a lack of transparency. This work provides an overall picture of current strategies for the definition of the reimbursed prices of orphan drugs (ODs) and highlights some potential improvements. Current strategies and suggestions are presented along 4 dimensions: (1) comprehensive value assessment, (2) early dialogs among relevant stakeholders, (3) innovative reimbursement approaches, and (4) societal participation in producing ODs. Comprehensive value assessment could be achieved by clarifying the approach of distributive justice to adopt, ensuring a representative participation of stakeholders, and with a broad consideration of value-bearing factors. With respect to early dialogs, cross-border cooperation can be determinant to companies and agencies. The cost-benefit ratio of early dialogs needs to be demonstrated and the "regulatory capture" effect should be monitored. Innovative reimbursement approaches were developed to balance the need for evidence-based decisions with the timely access to innovative drugs. The societal participation in producing ODs needs to be recognised in a collaborating framework where adaptive agreements can be developed with mutual satisfaction. Such agreements could also impact on coverage and reimbursement decisions as additional elements for the determination of a comprehensive societal value of ODs. Further research is needed to investigate the highlighted open challenges so that RDs will not remain, in practical terms, orphan diseases. © 2017 S. Karger AG, Basel.

  9. [Current status and potential perspectives in classical radiotherapy technology].

    Science.gov (United States)

    Dabić-Stanković, Kata M; Stanković, Jovan B; Radosević-Jelić, Ljiljana M

    2004-01-01

    After purchase of radiotherapy equipment in 2003, classic radiation therapy in Serbia will reach the highest world level. In order to define the highest standards in radiation technology, we analyzed the current status and potential perspectives of radiation therapy. An analysis of present situation in the USA, assumed as the most developed in the world, was done. Available data, collected in the last 3 years (equipment assortment, therapy modalities, workload and manpower) for 284 radiotherapy centers, out of potential 2050, were analyzed. Results were presented as crude percentage and matched to point current status. The analysis showed that CLINAC accelerators are the most popular (82.7%), as well as, ADAC (43.7%) and Focus (CMS) (27.4%) systems for therapy planning. Movement towards virtual simulation is evident (59.3%), although classic "simulation" is not fully eliminated from the radiotherapy chain. The most popular brachytherapy afterloader is Microselectron HDR (71%). About 64.4% centers use IMPAC communication/verification/record system that seems more open than Varis. All centers practice modern radiotherapy modalities and techniques (CPRT, IMRT, SRS/SRT, TBI, IORT, IVBHRT, HDR BHRT, etc.). CT and MRI availability is out of question, but PET is available in 3% of centers, however this percentage is rapidly growing. Up to 350 new patients per year are treated by one accelerator (about 35 pts. a day). Centers are relatively small and utilize 2-3 accelerators on average. Average FTE staffing norm is 4 radiation oncologists, 2-3 medical radiotherapy physicists, about 3 certified medical dosimetrists and about 6 radiotherapy technologists. In the past 5 years relative stagnation in classic radiotherapy has been observed. In spite of substantial investments in technology and consequent improvements, as well as wide introduction of computers in radiotherapy, radiotherapy results have not changed significantly. Vendor developement strategies do not point that

  10. Current use and potential of additive manufacturing for optical applications

    Science.gov (United States)

    Brunelle, Matthew; Ferralli, Ian; Whitsitt, Rebecca; Medicus, Kate

    2017-10-01

    Additive manufacturing, or 3D printing, has become widely used in recent years for the creation of both prototype and end-use parts. Because the parts are created in a layer-by-layer manner, the flexibility of additive manufacturing is unparalleled and has opened the design space to enable features like undercuts and internal channels which cannot exist on traditional, subtractively manufactured parts. This flexibility can also be leveraged for optical applications. This paper outlines some of the current uses of 3D printing in the optical manufacturing process at Optimax. Several materials and additive technologies are utilized, including polymer printing through fused deposition modeling, which creates parts by depositing a softened thermoplastic filament in a layerwise fashion. Stereolithography, which uses light to cure layers of a photopolymer resin, will also be discussed. These technologies are used to manufacture functional prototypes, fixtures, sealed housings, and other components. Additionally, metal printing through selective laser melting, which uses a laser to melt metal powder layers into a dense solid, will be discussed due to the potential to manufacture thermally stable opticalmechanical assembly frameworks and functional optics. Examples of several additively manufactured optical components will be shown.

  11. Determination of J-integral R-curves for the pressure vessel material A 533 B1 using the potential drop technique and the multi-specimen method

    International Nuclear Information System (INIS)

    Krompholz, K.; Ullrich, G.

    1985-01-01

    J-integral experiments at room temperature were performed on three point bend type specimens of the nuclear pressure vessel material A 533 B1 with a/w-ratios of 0.3 and 0.5. Following the ASTM-proposal for the multi-specimen technique a value is obtained close to the value obtained in the HSST round robin test. On the other hand, from the measurement of the Jsub(IC)-value by means of the potential drop technique there is an indication that a lower value of Jsub(IC) is correct. This is in agreement with the multi-specimen technique using linear regression lines without excluding 'invalid' points. That is reasonable if fractographic investigations gives clear indications that stable crack growth has occurred as is the case in this work. (Auth.)

  12. The current-voltage characteristic and potential oscillations of a double layer in a triple plasma device

    International Nuclear Information System (INIS)

    Carpenter, R.T.; Torven, S.

    1986-07-01

    The properties of a strong double layer in a current circuit with a capacitance and an inductance are investigated in a triple plasma device. The double layer gives rise to a region of negative differential resistance in the current-voltage characteristic of the device, and this gives non-linear oscillations in the current and the potential drop over the double layer (PhiDL). For a sufficiently large circuit inductance PhiDL reaches an amplitude given by the induced voltage (-LdI/dt) which is much larger than the circuit EMF due to the rapid current decrease when PhiDL increases. A variable potential minimum exists in the plasma on the low potential side of the double layer, and the depth of the minimum increases when PhiDL increases. An increasing fraction of the electrons incident at the double layer are then reflected, and this is found to be the main process giving rise to the negative differential resistance. A qualitative model for the variation of the minimum potential with PhiDL is also proposed. It is based on the condition that the minimum potential must adjust itself self-consistentely so that quasi-neutrality is maintained in the plasma region where the minimum is assumed. (authors)

  13. The Drop Tower Bremen -Experiment Operation

    Science.gov (United States)

    Könemann, Thorben; von Kampen, Peter; Rath, Hans J.

    The idea behind the drop tower facility of the Center of Applied Space Technology and Micro-gravity (ZARM) in Bremen is to provide an inimitable technical opportunity of a daily access to short-term weightlessness on earth. In this way ZARM`s european unique ground-based microgravity laboratory displays an excellent economic alternative for research in space-related conditions at low costs comparable to orbital platforms. Many national and international ex-perimentalists motivated by these prospects decide to benefit from the high-quality and easy accessible microgravity environment only provided by the Drop Tower Bremen. Corresponding experiments in reduced gravity could open new perspectives of investigation methods and give scientists an impressive potential for a future technology and multidisciplinary applications on different research fields like Fundamental Physics, Astrophysics, Fluid Dynamics, Combus-tion, Material Science, Chemistry and Biology. Generally, realizing microgravity experiments at ZARM`s drop tower facility meet new requirements of the experimental hardware and may lead to some technical constraints in the setups. In any case the ZARM Drop Tower Operation and Service Company (ZARM FAB mbH) maintaining the drop tower facility is prepared to as-sist experimentalists by offering own air-conditioned laboratories, clean rooms, workshops and consulting engineers, as well as scientific personal. Furthermore, ZARM`s on-site apartment can be used for accommodations during the experiment campaigns. In terms of approaching drop tower experimenting, consulting of experimentalists is mandatory to successfully accomplish the pursued drop or catapult capsule experiment. For this purpose there will be a lot of expertise and help given by ZARM FAB mbH in strong cooperation to-gether with the experimentalists. However, in comparison to standard laboratory setups the drop or catapult capsule setup seems to be completely different at first view. While defining a

  14. Market potential of superconductor current limiters; Marktpotential von supraleitenden Strombegrenzern

    Energy Technology Data Exchange (ETDEWEB)

    Lakner, M.; Braun, D. [ABB Schweiz AG, Corporate Research, Baden-Daettwil (Switzerland); Schnyder, G.; Mauchle, P. [Schnyder Ingenieure AG, Huenenberg (Switzerland)

    2003-07-01

    This final report for the Swiss Federal Office of Energy describes the two concepts - 'resistive' and 'inductive' - used for Superconducting Fault Current Limiters (SCFCL) that utilise the transition from zero to finite resistance to limit short-circuit currents. The main advantages of SCFCL are compared to other current-limiting technologies: They can limit any type of prospective fault current, operate fail-safe, be self-triggered and self-restoring. Their main disadvantage - the cooling effort necessary - is also discussed. The application possibilities of SCFCL were investigated by simulating the impact on utility and industrial grids. Applications of SCFCL such as the coupling of medium-voltage grids and their use in series with a circuit-breaker on the secondary side of a substation transformer are discussed. It is also shown that, by using fault current limiters, considerable cost savings can be made, especially in connection with new installations or the extension of existing plants.

  15. Massive Open Online Courses (MOOCs): Current Applications and Future Potential

    Science.gov (United States)

    Milheim, William D.

    2013-01-01

    Massive Open Online Courses (or MOOCs) are the subject of numerous recent articles in "The Chronicle of Higher Education," "The New York Times," and other publications related to their increasing use by a variety of universities to reach large numbers of online students. This article describes the current state of these online…

  16. Transmutation potential of current and innovative nuclear power systems

    International Nuclear Information System (INIS)

    Slessarev, I.; Salvatores, M.; Uematsu, M.

    1993-01-01

    In the present paper we have investigated the transmutation potential of different nuclear systems from a physical point of view. Transuranium (TRU) elements have been considered, but also long lived fission products (LLFP). The potential for transmutation has to take into account not only the consumption of a specific nucleus (or of a specific 'family' of nuclei), but also the reproduction of other nuclei of higher masses. The present study allows an intercomparison taking into account both aspects. Technological, safety and design constraints were not considered at this stage. However strategic indications for future studies have been obtained. 3 refs., 3 tabs

  17. Current status and future potential for advanced volume reduction technologies

    International Nuclear Information System (INIS)

    Rutland, L.; Naughton, M.D.; Papaiya, N.C.

    1984-01-01

    With escalating costs for disposal of low-level radioactive waste (LLW) from nuclear power plants, and the possibility of unavailability of disposal space, some nuclear power utilities responded by commiting to implementing advanced volume reduction (VR) systems. This paper presents recent experience to implement advanced volume reduction technologies; their performance and typical operating and capital costs. This experience in the light of current economic conditions may enable us to predict the direction that future advanced VR technology commitments is taking

  18. Current assessment and future potential of the international nuclear market

    International Nuclear Information System (INIS)

    Cassidy, P.R.

    1983-01-01

    This is a study of the current and future situation of the international nuclear market. This paper highlights the projections as seen not only by Bechtel Power Corporation, but also by the international nuclear community. It covers in particular the electric power growth projection; the percentage of probable nuclear power generation; operating services for existing nuclear power plants; and the nuclear fuel cycle. (NEA) [fr

  19. Therapeutic potential of snake venom in cancer therapy: current perspectives

    Science.gov (United States)

    Vyas, Vivek Kumar; Brahmbhatt, Keyur; Bhatt, Hardik; Parmar, Utsav

    2013-01-01

    Many active secretions produced by animals have been employed in the development of new drugs to treat diseases such as hypertension and cancer. Snake venom toxins contributed significantly to the treatment of many medical conditions. There are many published studies describing and elucidating the anti-cancer potential of snake venom. Cancer therapy is one of the main areas for the use of protein peptides and enzymes originating from animals of different species. Some of these proteins or peptides and enzymes from snake venom when isolated and evaluated may bind specifically to cancer cell membranes, affecting the migration and proliferation of these cells. Some of substances found in the snake venom present a great potential as anti-tumor agent. In this review, we presented the main results of recent years of research involving the active compounds of snake venom that have anticancer activity. PMID:23593597

  20. Intradermal delivery of vaccines: potential benefits and current challenges

    Science.gov (United States)

    Hickling, JK; Jones, KR; Friede, M; Chen, D; Kristensen, D

    2011-01-01

    Abstract Delivery of vaccine antigens to the dermis and/or epidermis of human skin (i.e. intradermal delivery) might be more efficient than injection into the muscle or subcutaneous tissue, thereby reducing the volumes of antigen. This is known as dose-sparing and has been demonstrated in clinical trials with some, but not all, vaccines. Dose-sparing could be beneficial to immunization programmes by potentially reducing the costs of purchase, distribution and storage of vaccines; increasing vaccine availability and effectiveness. The data obtained with intradermal delivery of some vaccines are encouraging and warrant further study and development; however significant gaps in knowledge and operational challenges such as reformulation, optimizing vaccine presentation and development of novel devices to aid intradermal vaccine delivery need to be addressed. Modelling of the costs and potential savings resulting from intradermal delivery should be done to provide realistic expectations of the potential benefits and to support cases for investment. Implementation and uptake of intradermal vaccine delivery requires further research and development, which depends upon collaboration between multiple stakeholders in the field of vaccination. PMID:21379418

  1. Triclosan: Current Status, Occurrence, Environmental Risks and Bioaccumulation Potential

    Directory of Open Access Journals (Sweden)

    Gurpreet Singh Dhillon

    2015-05-01

    Full Text Available Triclosan (TCS is a multi-purpose antimicrobial agent used as a common ingredient in everyday household personal care and consumer products. The expanded use of TCS provides a number of pathways for the compound to enter the environment and it has been detected in sewage treatment plant effluents; surface; ground and drinking water. The physico-chemical properties indicate the bioaccumulation and persistence potential of TCS in the environment. Hence, there is an increasing concern about the presence of TCS in the environment and its potential negative effects on human and animal health. Nevertheless, scarce monitoring data could be one reason for not prioritizing TCS as emerging contaminant. Conventional water and wastewater treatment processes are unable to completely remove the TCS and even form toxic intermediates. Considering the worldwide application of personal care products containing TCS and inefficient removal and its toxic effects on aquatic organisms, the compound should be considered on the priority list of emerging contaminants and its utilization in all products should be regulated.

  2. Current Capabilities and Development Potential in Surgical Robotics

    Directory of Open Access Journals (Sweden)

    Mathias Hoeckelmann

    2015-05-01

    Full Text Available Commercial surgical robots have been in clinical use since the mid-1990s, supporting surgeons in various tasks. In the past decades, many systems emerged as research platforms, and a few entered the global market. This paper summarizes the currently available surgical systems and research directions in the broader field of surgical robotics. The widely deployed teleoperated manipulators aim to enhance human cognitive and physical skills and provide smart tools for surgeons, while image-guided robotics focus on surpassing human limitations by introducing automated targeting and treatment delivery methods. Both concepts are discussed based on prototypes and commercial systems. Through concrete examples the possible future development paths of surgical robots are illustrated. While research efforts are taking different approaches to improve the capacity of such systems, the aim of this survey is to assess their maturity from the commercialization point of view.

  3. How to know and choose online games: differences between current and potential players.

    Science.gov (United States)

    Teng, Ching-I; Lo, Shao-Kang; Wang, Pe-Cheng

    2007-12-01

    This study investigated how different adolescent players acquire game information and the criteria they use in choosing online games and found that (1) current players generally use comprehensive information sources more than potential players do; (2) current players rely on free trials and smooth display of motion graphics as choice criteria more than potential players do; (3) potential players rely on the look of advertisements more than current players do; (4) both current and potential players most likely use word-of-mouth and gaming programs on TV as information sources; and (5) endorser attractiveness is ranked the least important among six choice criteria by both current and potential players.

  4. Respiratory gated radiotherapy: current techniques and potential benefits

    International Nuclear Information System (INIS)

    Giraud, P.; Campana, F.; Rosenwald, J.C.; Cosset, J.M.; Reboul, F.; Garcia, R.; Clippe, S.; Carrie, C.; Dubray, B.

    2003-01-01

    Respiration-gated radiotherapy offers a significant potential for improvement in the irradiation of tumor sites affected by respiratory motion such as lung, breast and liver tumors. An increased conformality of irradiation fields leading to decreased complications rates of organs at risk (lung, heart...) is expected. Respiratory gating is in line with the need for improved precision required by radiotherapy techniques such as 3D conformal radiotherapy or intensity modulated radiotherapy. Reduction of respiratory motion can be achieved by using either breath hold techniques or respiration synchronized gating techniques. Breath-hold techniques can be achieved with active, in which airflow of the patient is temporarily blocked by a valve, or passive techniques, in which the patient voluntarily breath-hold. Synchronized gating techniques use external devices to predict the phase of the respiration cycle while the patient breaths freely. These techniques presently investigated in several medical centers worldwide. Although promising, the first results obtained in lung and liver cancer patients require confirmation. Physical, technical and physiological questions still remain to be answered. This paper describes the most frequently used gated techniques and the main published clinical reports on the use of respiration-gated radiotherapy in order to evaluate the impact of these techniques. (author)

  5. Alluvial aquifers in the Mzingwane catchment: Their distribution, properties, current usage and potential expansion

    Science.gov (United States)

    Moyce, William; Mangeya, Pride; Owen, Richard; Love, David

    The Mzingwane River is a sand filled channel, with extensive alluvial aquifers distributed along its banks and bed in the lower catchment. LandSat TM imagery was used to identify alluvial deposits for potential groundwater resources for irrigation development. On the false colour composite band 3, band 4 and band 5 (FCC 345) the alluvial deposits stand out as white and dense actively growing vegetation stands out as green making it possible to mark out the lateral extent of the saturated alluvial plain deposits using the riverine fringe and vegetation . The alluvial aquifers form ribbon shaped aquifers extending along the channel and reaching over 20 km in length in some localities and are enhanced at lithological boundaries. These alluvial aquifers extend laterally outside the active channel, and individual alluvial aquifers have been measured with area ranging from 45 ha to 723 ha in the channels and 75 ha to 2196 ha on the plains. The alluvial aquifers are more pronounced in the Lower Mzingwane, where the slopes are gentler and allow for more sediment accumulation. Estimated water resources potential ranges between 175,000 m 3 and 5,430,000 m 3 in the channels and between 80,000 m 3 and 6,920,000 m 3 in the plains. Such a water resource potential can support irrigation ranging from 18 ha to 543 ha for channels alluvial aquifers and 8 ha to 692 ha for plain alluvial aquifers. Currently, some of these aquifers are being used to provide water for domestic use, livestock watering and dip tanks, commercial irrigation and market gardening. The water quality of the aquifers in general is fairly good due to regular recharge and flushing out of the aquifers by annual river flows and floodwater. Water salinity was found to increase significantly in the end of the dry season, and this effect was more pronounced in water abstracted from wells on the alluvial plains. During drought years, recharge is expected to be less and if the drought is extended water levels in the

  6. Current and potential ant impacts in the Pacific region

    Science.gov (United States)

    Loope, Lloyd L.; Krushelnycky, Paul D.

    2007-01-01

    Worldwide, ants are a powerful ecological force, and they appear to be dominant components of animal communities of many tropical and temperate ecosystems in terms of biomass and numbers of individuals (Bluthgen et al. 2000). For example, ants comprise up to 94% of arthropod individuals in fogging samples taken from diverse lowland tropical rainforest canopies, and 86% of the biomass (Davidson et al. 2003). The majority of these ant species and individuals obtain carbohydrates either from extrafloral nectaries or from sap-feeding Hemiptera that pass carbohydrate-rich “honeydew” to attending ants while concentrating nitrogen (N) from N-poor plant sap (Davidson et al. 2003). Honeydew and nectar represent key resources for arboreal ant species, although most ant species are at least partly carnivorous or scavengers (Bluthgen et al. 2004). In contrast to most of the terrestrial world, the biotas of many Pacific islands evolved without ants. Whereas endemic ant species are found in New Zealand (ca. 10 spp.), Tonga (ca. 10 spp.), and Samoa (ca. 12 spp.), other islands of Polynesia and parts of Micronesia likely lack native ants (Wilson and Taylor 1967, Wetterer 2002, Wetterer and Vargo 2003). About 20 Indo-Australian and western Pacific ant species range to the east and north of Samoa, but it is unclear how many of these were transported there by humans at some time (Wilson and Taylor 1967). Most of the remainder of the ant species currently found on Pacific islands are widespread species that fall in the category of “tramp species,” dispersed by recent human commerce and generally closely tied to human activity and urban areas (Wilson and Taylor 1967, McGlynn 1999). In Pacific island situations, some of these tramp ant species are able to thrive beyond areas of human activity. Relatively few ant species have been successful invaders of native communities on continents, and these include most of the species that pose the greatest problems for Pacific islands

  7. SARAL/Altika for inland water: current and potential applications

    Science.gov (United States)

    Tarpanelli, Angelica; Brocca, Luca; Barbetta, Silvia; Moramarco, Tommaso; Santos da Silva, Joécila; Calmant, Stephane

    2015-04-01

    Although representing less than 1% of the total amount of water on Earth the freshwater is essential for terrestrial life and human needs. Over one third of the world's population is not served by adequate supplies of clean water and for this reason freshwater wars are becoming one of the most pressing environmental issues exacerbating the already difficult tensions between the riparian nations. Notwithstanding the foregoing, we have surprisingly poor knowledge of the spatial and temporal dynamics of surface discharge. In-situ gauging networks quantify the instantaneous water volume in the main river channels but provide few information about the spatial dynamics of surface water extent, such as floodplain flows and the dynamics of wetlands. The growing reduction of hydrometric monitoring networks over the world, along with the inaccessibility of many remote areas and the difficulties for data sharing among developing countries feed the need to develop new procedures for river discharge estimation based on remote sensing technology. The major challenge in this case is the possibility of using Earth Observation data without ground measurements. Radar altimeters are a valuable tool to retrieve hydrological information from space such as water level of inland water. More than a decade of research on the application of radar altimetry has demonstrated its advantages also for monitoring continental water, providing global coverage and regular temporal sampling. The high accuracy of altimetry data provided by the latest spatial missions and the convincing results obtained in the previous applications suggest that these data may be employed for hydraulic/hydrological applications as well. If used in synergy with the modeling, the potential benefits of the altimetry measurements can grow significantly. The new SARAL French-Indian mission, providing improvements in terms of vertical accuracy and spatial resolution of the onboard altimeter Altika, can offer a great

  8. Dynamics of the inward rectifier K+ current during the action potential of guinea pig ventricular myocytes

    OpenAIRE

    Ibarra, J.; Morley, G.E.; Delmar, M.

    1991-01-01

    The potassium selective, inward rectifier current (IK1) is known to be responsible for maintaining the resting membrane potential of quiescent ventricular myocytes. However, the contribution of this current to the different phases of the cardiac action potential has not been adequately established. In the present study, we have used the action potential clamp (APC) technique to characterize the dynamic changes of a cesium-sensitive (i.e., Ik1) current which occur during the action potential. ...

  9. Dynamics of deforming drops

    OpenAIRE

    Bouwhuis, W.

    2015-01-01

    Liquid drops play a dominant role in numerous industrial applications, such as spray coating, spray painting, inkjet printing, lithography processes, and spraying/sprinkling in agriculture or gardening. In all of these examples, the generation, flight, impact, and spreading of drops are separate stages of the corresponding industrial processes, which are all thoroughly studied for many years. This thesis focuses on drop dynamics, impact phenomena, Leidenfrost drops, and pouring flows. Based o...

  10. Dropping out of school

    Directory of Open Access Journals (Sweden)

    M. Teneva

    2017-09-01

    Full Text Available The modern technological society needs educated people who, through their high professionalism, are called upon to create its progress. In this aspect, a serious problem stands out – the dropout from school of a large number of children, adolescents and young people. The object of the research is the premature interruption of training for a large number of Bulgarian students. The subject of the study is the causes that provoke the students’ dropping out of school. The aim is to differentiate the negative factors leading to dropping out of school, and to identify the motivating factors that encourage the individual to return to the educational environment. In order to realize the so set target, a specially designed test-questionnaire has been used. The survey was conducted among students attending evening courses who have left their education for various reasons and are currently back to the school institution. The contingent of the study includes 120 students from the evening schools. The results indicate that the reasons which prompted the students to leave school early differentiate into four groups: family, social, economic, educational, personal. The motivation to return to school has been dictated in the highest degree by the need for realization of the person on the labor market, followed by the possibility for full social functioning.

  11. Assessing current and future techno-economic potential of concentrated solar power and photovoltaic electricity generation

    International Nuclear Information System (INIS)

    Köberle, Alexandre C.; Gernaat, David E.H.J.; Vuuren, Detlef P. van

    2015-01-01

    CSP and PV technologies represent energy sources with large potentials. We present cost-supply curves for both technologies using a consistent methodology for 26 regions, based on geoexplicit information on solar radiation, land cover type and slope, exploring individual potential and interdependencies. For present day, both CSP and PV supply curves start at $0.18/kWh, in North Africa, South America, and Australia. Applying accepted learning rates to official capacity targets, we project prices to drop to $0.11/kWh for both technologies by 2050. In an alternative “fast-learning” scenario, generation costs drop to $0.06–0.07/kWh for CSP, and $0.09/kWh for PV. Competition between them for best areas is explored along with sensitivities of their techno-economic potentials to land use restrictions and land cover type. CSP was found to be more competitive in desert sites with highest direct solar radiation. PV was a clear winner in humid tropical regions, and temperate northern hemisphere. Elsewhere, no clear winner emerged, highlighting the importance of competition in assessments of potentials. Our results show there is ample potential globally for both technologies even accounting for land use restrictions, but stronger support for RD&D and higher investments are needed to make CSP and PV cost-competitive with established power technologies by 2050. - Highlights: • A consistent assessment of global potential for CSP and PV, with cost-supply curves for 26 regions. • Combined global CSP and PV potential below US$0.35/kWh estimated at 135,128 TWh per year. • Competition for same land-based solar resource implies that potentials cannot be added. • Attractive areas are MENA, Northern Chile, Australia, China and Southwestern USA. • Costs are projected to go down over time, reaching US$0.06–0.11/KWh for attractive sites in 2050

  12. The components of the adsorption potential drop at the Ga and In-Ga electrodes in three solvents: a calculation with allowance for hydrophily of the Ag(111) single crystal face

    International Nuclear Information System (INIS)

    Emets, V.V.; Damaskin, B.B.; Kazarinov, V.E.

    1996-01-01

    The components of adsorption potential drop on the Ga and In-Ga electrodes in water, DMPA and DSMO, taking into account hydrophily of Ag(111) single crystal face in the framework of the metal-solvent contact modified model, have been recalculated. The data obtained are compared with the previously acquired ones. It is pointed out that corrections for the components of adsorptional potential relating to account of Ag(111) face hydrophily are not negligible. 8 refs., 1 tab

  13. Potential Magnetic Field around a Helical Flux-rope Current Structure in the Solar Corona

    OpenAIRE

    Petrie, G. J. D.

    2007-01-01

    We consider the potential magnetic field associated with a helical electric line current flow, idealizing the near-potential coronal field within which a highly localized twisted current structure is embedded. It is found that this field has a significant axial component off the helical magnetic axis where there is no current flow, such that the flux winds around the axis. The helical line current field, in including the effects of flux rope writhe, is therefore more topologically complex tha...

  14. Electrohydrodynamics of suspension of liquid drops in AC fields

    Science.gov (United States)

    Abdul Halim, Md.; Esmaeeli, Asghar

    2012-11-01

    Manipulation of liquid drops by an externally applied electric field is currently the focus of increased attention because of its relevance in a broad range of industrial processes. The effect of a uniform DC electric field on a solitary drop is well studied; however, less is know about the impact of electric field on suspension of liquid drops, and very little information is available on the impact of AC field on a single or a suspension of drops. Here we report the results of Direct Numerical Simulations of electrohydrodynamics of suspension of liquid drops. The governing equations are solved using a front tracking/finite difference technique, in conjunction with Taylor's leaky dielectric model. The imposed electric potential comprises of two parts, a time-independent base and a time-dependent part. The goal is to explore the relative importance of these two components in setting the statistically steady state behavior of the suspension. To this end, we report the results of three sets of simulations, where (i) the time-dependent part act as a perturbation on the base potential, (ii) the two components are of the same order, and (iii) the time-dependent part is much larger than the base potential. The problem is studied as a function of the governing nondimensional parameters.

  15. Analysis of output currents of self-powered detectors polarized by an external potential

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, K; Glowacki, S

    1980-01-01

    During measurement of self-powered detector current the electrical potential is induced between the emitter and collector caused by the input resistivity of measuring device. The detector current dependence on the emitter potential has been analyzed. The experimental results confirm the theoretical model of electronic processes within the insulator and also give the requirements that measuring device should fulfil.

  16. Scanning drop sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jian; Xiang, Chengxiang; Gregoire, John

    2017-05-09

    Electrochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

  17. Scanning drop sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Shinde, Aniketa A.; Guevarra, Dan W.; Jones, Ryan J.; Marcin, Martin R.; Mitrovic, Slobodan

    2017-05-09

    Electrochemical or electrochemical and photochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

  18. A magnetic vector potential corresponding to a centrally conservative current element force

    International Nuclear Information System (INIS)

    Minteer, Timothy M

    2015-01-01

    The magnetic vector potential (Coulomb gauge) is commonly introduced in magnetostatic chapters of electromagnetism textbooks. However, what is not typically presented are the infinite subsets of the Coulomb gauge associated with differential current elements. This work provides a comparison of various differential magnetic vector potentials, differential magnetostatic potential energies, as well as differential current element forces as a collective work not available elsewhere. The differential magnetic vector potential highlighted in this work is the Coulomb–Ampère gauge corresponding to the centrally conservative Ampère current element force. The centrally conservative force is modeled as a mean valued continual exchange of energy carrier mediators accounting for both the differential magnetostatic potential energy and Ampère current element force of two differential current elements. (paper)

  19. Nonlinear oscillations of inviscid free drops

    Science.gov (United States)

    Patzek, T. W.; Benner, R. E., Jr.; Basaran, O. A.; Scriven, L. E.

    1991-01-01

    The present analysis of free liquid drops' inviscid oscillations proceeds through solution of Bernoulli's equation to obtain the free surface shape and of Laplace's equation for the velocity potential field. Results thus obtained encompass drop-shape sequences, pressure distributions, particle paths, and the temporal evolution of kinetic and surface energies; accuracy is verified by the near-constant drop volume and total energy, as well as the diminutiveness of mass and momentum fluxes across drop surfaces. Further insight into the nature of oscillations is provided by Fourier power spectrum analyses of mode interactions and frequency shifts.

  20. Axisymmetric Liquid Hanging Drops

    Science.gov (United States)

    Meister, Erich C.; Latychevskaia, Tatiana Yu

    2006-01-01

    The geometry of drops hanging on a circular capillary can be determined by numerically solving a dimensionless differential equation that is independent on any material properties, which enables one to follow the change of the height, surface area, and contact angle of drops hanging on a particular capillary. The results show that the application…

  1. Turbulence, bubbles and drops

    NARCIS (Netherlands)

    van der Veen, Roeland

    2016-01-01

    In this thesis, several questions related to drop impact and Taylor-Couette turbulence are answered. The deformation of a drop just before impact can cause a bubble to be entrapped. For many applications, such as inkjet printing, it is crucial to control the size of this entrapped bubble. To study

  2. Dynamics of deforming drops

    NARCIS (Netherlands)

    Bouwhuis, W.

    2015-01-01

    Liquid drops play a dominant role in numerous industrial applications, such as spray coating, spray painting, inkjet printing, lithography processes, and spraying/sprinkling in agriculture or gardening. In all of these examples, the generation, flight, impact, and spreading of drops are separate

  3. Current knowledge of US metal and nonmetal miner health: Current and potential data sources for analysis of miner health status

    Science.gov (United States)

    Yeoman, K. M.; Halldin, C. N.; Wood, J.; Storey, E.; Johns, D.; Laney, A. S.

    2016-01-01

    ABSTRACT Little is known about the current health status of US metal and nonmetal (MNM) miners, in part because no health surveillance systems exist for this population. The National Institute for Occupational Safety and Health (NIOSH) is developing a program to characterize burden of disease among MNM miners. This report discusses current knowledge and potential data sources of MNM miner health. Recent national surveys were analyzed, and literature specific to MNM miner health status was reviewed. No robust estimates of disease prevalence were identified, and national surveys did not provide information specific to MNM miners. Because substantial gaps exist in the understanding of MNM miners' current health status, NIOSH plans to develop a health surveillance program for this population to guide intervention efforts to reduce occupational and personal risks for chronic illness. PMID:25658684

  4. Current Reversal Due to Coupling Between Asymmetrical Driving Force and Ratchet Potential

    International Nuclear Information System (INIS)

    Ai Baoquan; Xie Huizhang; Liu Lianggang

    2006-01-01

    Transport of a Brownian particle moving in a periodic potential is investigated in the presence of an asymmetric unbiased external force. The asymmetry of the external force and the asymmetry of the potential are the two ways of inducing a net current. It is found that the competition of the spatial asymmetry of potential with the temporal asymmetry of the external force leads to the phenomena like current reversal. The competition between the two opposite driving factors is a necessary but not a sufficient condition for current reversals.

  5. Melatonin potentiates glycine currents through a PLC/PKC signalling pathway in rat retinal ganglion cells.

    Science.gov (United States)

    Zhao, Wen-Jie; Zhang, Min; Miao, Yanying; Yang, Xiong-Li; Wang, Zhongfeng

    2010-07-15

    In vertebrate retina, melatonin regulates various physiological functions. In this work we investigated the mechanisms underlying melatonin-induced potentiation of glycine currents in rat retinal ganglion cells (RGCs). Immunofluorescence double labelling showed that rat RGCs were solely immunoreactive to melatonin MT(2) receptors. Melatonin potentiated glycine currents of RGCs, which was reversed by the MT(2) receptor antagonist 4-P-PDOT. The melatonin effect was blocked by intracellular dialysis of GDP-beta-S. Either preincubation with pertussis toxin or application of the phosphatidylcholine (PC)-specific phospholipase C (PLC) inhibitor D609, but not the phosphatidylinositol (PI)-PLC inhibitor U73122, blocked the melatonin effect. The protein kinase C (PKC) activator PMA potentiated the glycine currents and in the presence of PMA melatonin failed to cause further potentiation of the currents, whereas application of the PKC inhibitor bisindolylmaleimide IV abolished the melatonin-induced potentiation. The melatonin effect persisted when [Ca(2+)](i) was chelated by BAPTA, and melatonin induced no increase in [Ca(2+)](i). Neither cAMP-PKA nor cGMP-PKG signalling pathways seemed to be involved because 8-Br-cAMP or 8-Br-cGMP failed to cause potentiation of the glycine currents and both the PKA inhibitor H-89 and the PKG inhibitor KT5823 did not block the melatonin-induced potentiation. In consequence, a distinct PC-PLC/PKC signalling pathway, following the activation of G(i/o)-coupled MT(2) receptors, is most likely responsible for the melatonin-induced potentiation of glycine currents of rat RGCs. Furthermore, in rat retinal slices melatonin potentiated light-evoked glycine receptor-mediated inhibitory postsynaptic currents in RGCs. These results suggest that melatonin, being at higher levels at night, may help animals to detect positive or negative contrast in night vision by modulating inhibitory signals largely mediated by glycinergic amacrine cells in the inner

  6. Drop "impact" on an airfoil surface.

    Science.gov (United States)

    Wu, Zhenlong

    2018-05-17

    Drop impact on an airfoil surface takes place in drop-laden two-phase flow conditions such as rain and icing, which are encountered by wind turbines or airplanes. This phenomenon is characterized by complex nonlinear interactions that manifest rich flow physics and pose unique modeling challenges. In this article, the state of the art of the research about drop impact on airfoil surface in the natural drop-laden two-phase flow environment is presented. The potential flow physics, hazards, characteristic parameters, droplet trajectory calculation, drop impact dynamics and effects are discussed. The most key points in establishing the governing equations for a drop-laden flow lie in the modeling of raindrop splash and water film. The various factors affecting the drop impact dynamics and the effects of drop impact on airfoil aerodynamic performance are summarized. Finally, the principle challenges and future research directions in the field as well as some promising measures to deal with the adverse effects of drop-laden flows on airfoil performance are proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Minimizing the magnetohydrodynamic potential energy for the current hole region in tokamaks

    International Nuclear Information System (INIS)

    Chu, M.S.; Parks, P.B.

    2004-01-01

    The current hole region in the tokamak has been observed to arise naturally during the development of internal transport barriers. The magnetohydrodynamic (MHD) potential energy in the current hole region is shown to be determined completely in terms of the displacements at the edge of the current hole. For modes with finite toroidal mode number n≠0, the minimized potential energy is the same as if the current hole region were a vacuum region. For modes with toroidal mode number n=0, the displacement is a superposition of three types of independent displacements: a vertical displacement or displacements that compress only the plasma, or the toroidal field uniformly. Thus for ideal MHD perturbations of plasma with a current hole, the plasma behaves as if it were bordered by an extra ''internal vacuum region.'' The relevance of the present work to computer simulations of plasma with a current hole region is also discussed

  8. MINIMIZING THE MHD POTENTIAL ENERGY FOR THE CURRENT HOLE REGION IN TOKAMAKS

    International Nuclear Information System (INIS)

    CHU, M.S; PARKS, P.B

    2004-01-01

    The current hole region in the tokamak has been observed to arise naturally during the development of internal transport barriers. The magnetohydrodynamic (MHD) potential energy in the current hole region is shown to be determined completely in terms of the displacements at the edge of the current hole. For modes with finite toroidal mode number n ≠ 0, the minimized potential energy is the same as if the current hole region were a vacuum region. For modes with toroidal mode number n = 0, the displacement is a superposition of three types of independent displacements: a vertical displacement or displacements that compress only the plasma or the toroidal field uniformly. Thus for ideal MHD perturbations of plasma with a current hole, the plasma behaves as if it were bordered by an extra ''internal vacuum region''. The relevance of the present work to computer simulations of plasma with a current hole region is also discussed

  9. Definition of current density in the presence of a non-local potential.

    Science.gov (United States)

    Li, Changsheng; Wan, Langhui; Wei, Yadong; Wang, Jian

    2008-04-16

    In the presence of a non-local potential arising from electron-electron interaction, the conventional definition of current density J(c) = (e/2m)([(p-eA)ψ](*)ψ-ψ(*)[(p-eA)ψ]) cannot satisfy the condition of current conservation, i.e., [Formula: see text] in the steady state. In order to solve this problem, we give a new definition of current density including the contribution due to the non-local potential. We show that the current calculated based on the new definition of current density conserves the current and is the same as that obtained from the Landauer-Büttiker formula. Examples are given to demonstrate our results.

  10. Chemical potential of quasi-equilibrium magnon gas driven by pure spin current.

    Science.gov (United States)

    Demidov, V E; Urazhdin, S; Divinskiy, B; Bessonov, V D; Rinkevich, A B; Ustinov, V V; Demokritov, S O

    2017-11-17

    Pure spin currents provide the possibility to control the magnetization state of conducting and insulating magnetic materials. They allow one to increase or reduce the density of magnons, and achieve coherent dynamic states of magnetization reminiscent of the Bose-Einstein condensation. However, until now there was no direct evidence that the state of the magnon gas subjected to spin current can be treated thermodynamically. Here, we show experimentally that the spin current generated by the spin-Hall effect drives the magnon gas into a quasi-equilibrium state that can be described by the Bose-Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of spin current-driven Bose-Einstein condensation.

  11. Definition of current density in the presence of a non-local potential

    International Nuclear Information System (INIS)

    Li Changsheng; Wan Langhui; Wei Yadong; Wang Jian

    2008-01-01

    In the presence of a non-local potential arising from electron-electron interaction, the conventional definition of current density J c = (e/2m)([(p-eA)ψ]*ψ-ψ*[(p-eA)ψ]) cannot satisfy the condition of current conservation, i.e., ∇ . J c ≠ 0 in the steady state. In order to solve this problem, we give a new definition of current density including the contribution due to the non-local potential. We show that the current calculated based on the new definition of current density conserves the current and is the same as that obtained from the Landauer-Buettiker formula. Examples are given to demonstrate our results

  12. "Who am I supposed to let down?": The caring work and emotional practices of vocational educational training teachers working with potential drop-out students

    DEFF Research Database (Denmark)

    Lippke, Lena

    2012-01-01

    initiatives and as a result, most colleges have established extended basic courses aimed at students with personal, social and/or academic difficulties. This paper aims to explore the emotional aspects of vocational educational teachers’ work and present a preliminary analysis of the notion of care....... Findings – The paper provides empirical insights into the emotional practices and the management of emotions related to prevention of dropout within an educational setting. It shows how emotional practices can provide both teachers and students with positive identities and make out a productive force...... that prevents students from dropping out. However the management of emotions also involves a range of dilemmas and ambivalences revealing the difficult limitations related to an institutionalization and professionalization of human care. Research limitations/implications – Because of the chosen research design...

  13. Electromotive Potential Distribution and Electronic Leak Currents in Working YSZ Based SOCs

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Jacobsen, Torben

    2009-01-01

    The size of electronic leak currents through the YSZ electrolyte of solid oxide cells have been calculated using basic solid state electrochemical relations and literature data. The distribution of the electromotive potential, of Galvani potential, of concentration of electrons, e, and electron...... holes, h, was also calculated as these parameters are the basis for the understanding of the electronic conductivity that causes the electronic leak currents. The results are illustrated with examples. The effects of electrolyte thickness, temperature and cell voltage on the electronic leak current...

  14. Four-point probe measurements using current probes with voltage feedback to measure electric potentials

    Science.gov (United States)

    Lüpke, Felix; Cuma, David; Korte, Stefan; Cherepanov, Vasily; Voigtländer, Bert

    2018-02-01

    We present a four-point probe resistance measurement technique which uses four equivalent current measuring units, resulting in minimal hardware requirements and corresponding sources of noise. Local sample potentials are measured by a software feedback loop which adjusts the corresponding tip voltage such that no current flows to the sample. The resulting tip voltage is then equivalent to the sample potential at the tip position. We implement this measurement method into a multi-tip scanning tunneling microscope setup such that potentials can also be measured in tunneling contact, allowing in principle truly non-invasive four-probe measurements. The resulting measurement capabilities are demonstrated for \

  15. Current matrix element in HAL QCD's wavefunction-equivalent potential method

    Science.gov (United States)

    Watanabe, Kai; Ishii, Noriyoshi

    2018-04-01

    We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wavefunction-equivalent potentials proposed by the HAL QCD collaboration. As a first step, a non-relativistic field theory with two-channel coupling is considered as the original theory, with which a wavefunction-equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and right eigenfunctions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out.

  16. Effects of tacrolimus on action potential configuration and transmembrane ion currents in canine ventricular cells.

    Science.gov (United States)

    Szabó, László; Szentandrássy, Norbert; Kistamás, Kornél; Hegyi, Bence; Ruzsnavszky, Ferenc; Váczi, Krisztina; Horváth, Balázs; Magyar, János; Bányász, Tamás; Pál, Balázs; Nánási, Péter P

    2013-03-01

    Tacrolimus is a commonly used immunosuppressive agent which causes cardiovascular complications, e.g., hypertension and hypertrophic cardiomyopathy. In spite of it, there is little information on the cellular cardiac effects of the immunosuppressive agent tacrolimus in larger mammals. In the present study, therefore, the concentration-dependent effects of tacrolimus on action potential morphology and the underlying ion currents were studied in canine ventricular cardiomyocytes. Standard microelectrode, conventional whole cell patch clamp, and action potential voltage clamp techniques were applied in myocytes enzymatically dispersed from canine ventricular myocardium. Tacrolimus (3-30 μM) caused a concentration-dependent reduction of maximum velocity of depolarization and repolarization, action potential amplitude, phase-1 repolarization, action potential duration, and plateau potential, while no significant change in the resting membrane potential was observed. Conventional voltage clamp experiments revealed that tacrolimus concentrations ≥3 μM blocked a variety of ion currents, including I(Ca), I(to), I(K1), I(Kr), and I(Ks). Similar results were obtained under action potential voltage clamp conditions. These effects of tacrolimus developed rapidly and were fully reversible upon washout. The blockade of inward currents with the concomitant shortening of action potential duration in canine myocytes is the opposite of those observed previously with tacrolimus in small rodents. It is concluded that although tacrolimus blocks several ion channels at higher concentrations, there is no risk of direct interaction with cardiac ion channels when applying tacrolimus in therapeutic concentrations.

  17. Effects of pioglitazone on cardiac ion currents and action potential morphology in canine ventricular myocytes.

    Science.gov (United States)

    Kistamás, Kornél; Szentandrássy, Norbert; Hegyi, Bence; Ruzsnavszky, Ferenc; Váczi, Krisztina; Bárándi, László; Horváth, Balázs; Szebeni, Andrea; Magyar, János; Bányász, Tamás; Kecskeméti, Valéria; Nánási, Péter P

    2013-06-15

    Despite its widespread therapeutical use there is little information on the cellular cardiac effects of the antidiabetic drug pioglitazone in larger mammals. In the present study, therefore, the concentration-dependent effects of pioglitazone on ion currents and action potential configuration were studied in isolated canine ventricular myocytes using standard microelectrode, conventional whole cell patch clamp, and action potential voltage clamp techniques. Pioglitazone decreased the maximum velocity of depolarization and the amplitude of phase-1 repolarization at concentrations ≥3 μM. Action potentials were shortened by pioglitazone at concentrations ≥10 μM, which effect was accompanied with significant reduction of beat-to-beat variability of action potential duration. Several transmembrane ion currents, including the transient outward K(+) current (Ito), the L-type Ca(2+) current (ICa), the rapid and slow components of the delayed rectifier K(+) current (IKr and IKs, respectively), and the inward rectifier K(+) current (IK1) were inhibited by pioglitazone under conventional voltage clamp conditions. Ito was blocked significantly at concentrations ≥3 μM, ICa, IKr, IKs at concentrations ≥10 μM, while IK1 at concentrations ≥30 μM. Suppression of Ito, ICa, IKr, and IK1 has been confirmed also under action potential voltage clamp conditions. ATP-sensitive K(+) current, when activated by lemakalim, was effectively blocked by pioglitazone. Accordingly, action potentials were prolonged by 10 μM pioglitazone when the drug was applied in the presence of lemakalim. All these effects developed rapidly and were readily reversible upon washout. In conclusion, pioglitazone seems to be a harmless agent at usual therapeutic concentrations. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Modulation of membrane potential by an acetylcholine-activated potassium current in trout atrial myocytes

    DEFF Research Database (Denmark)

    Molina, C.E.; Gesser, Hans; Llach, A.

    2007-01-01

    mV from 4.3 pA/pF to 27 pA/pF with an EC50 of 45 nM in atrial myocytes. Moreover, 3 nM ACh increased the slope conductance of Im fourfold, shifted its reversal potential from -78 ± 3 to -84 ± 3 mV, and stabilized the resting membrane potential at -92 ± 4 mV. ACh also shortened the action potential...... hypothesized that this is at least partly due to a small slope conductance of Im around the resting membrane potential in atrial myocytes. In accordance with this hypothesis, the slope conductance of Im was about sevenfold smaller in atrial than in ventricular myocytes. Interestingly, ACh increased Im at -120...... of an inwardly rectifying K+ current can modulate the membrane potential in the trout atrial myocytes and stabilize the resting membrane potential. teleost heart; IK,ACh; cholinergic modulation; action potential...

  19. [Effects of dauricine on action potentials and slow inward currents of guinea pig ventricular papillary muscles].

    Science.gov (United States)

    Li, S N; Zhang, K Y

    1992-11-01

    Effects of dauricine (Dau) on the action potentials (AP), the slow action potentials (SAP), and the slow inward currents (Isi) of guinea pig ventricular papillary muscles were observed by means of intracellular microelectrode and single sucrose gap voltage clamp technique. In the early stage, Dau shortened action potential duration 100 (APD100) and effective refractory period (ERP) (ERP/APD ERP, and APD20, significantly decreased action potential amplitude (APA), maximum velocity (Vmax), and overshot (OS) (ERP/APD > 1; P SAP induced by isoprenaline (P < 0.01), and remarkably inhibited Isi (P < 0.01). The results suggested that Dau exerted an inhibitory effect on Na+, Ca2+, and K+ channels.

  20. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    Science.gov (United States)

    Saive, Rebecca; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert; Kowalsky, Wolfgang

    2013-12-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces.

  1. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    International Nuclear Information System (INIS)

    Saive, Rebecca; Kowalsky, Wolfgang; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert

    2013-01-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces

  2. The sea surface currents as a potential factor in the estimation and monitoring of wave energy potential

    Science.gov (United States)

    Zodiatis, George; Galanis, George; Nikolaidis, Andreas; Stylianoy, Stavros; Liakatas, Aristotelis

    2015-04-01

    The use of wave energy as an alternative renewable is receiving attention the last years under the shadow of the economic crisis in Europe and in the light of the promising corresponding potential especially for countries with extended coastline. Monitoring and studying the corresponding resources is further supported by a number of critical advantages of wave energy compared to other renewable forms, like the reduced variability and the easier adaptation to the general grid, especially when is jointly approached with wind power. Within the framework, a number of countries worldwide have launched research and development projects and a significant number of corresponding studies have been presented the last decades. However, in most of them the impact of wave-sea surface currents interaction on the wave energy potential has not been taken into account neglecting in this way a factor of potential importance. The present work aims at filling this gap for a sea area with increased scientific and economic interest, the Eastern Mediterranean Sea. Based on a combination of high resolution numerical modeling approach with advanced statistical tools, a detailed analysis is proposed for the quantification of the impact of sea surface currents, which produced from downscaling the MyOcean-FO regional data, to wave energy potential. The results although spatially sensitive, as expected, prove beyond any doubt that the wave- sea surface currents interaction should be taken into account for similar resource analysis and site selection approaches since the percentage of impact to the available wave power may reach or even exceed 20% at selected areas.

  3. Current Reversals of an Underdamped Brownian Particle in an Asymmetric Deformable Potential

    Science.gov (United States)

    Cai, Chun-Chun; Liu, Jian-Li; Chen, Hao; Li, Feng-Guo

    2018-03-01

    Transport of an underdamped Brownian particle in a one-dimensional asymmetric deformable potential is investigated in the presence of both an ac force and a static force, respectively. From numerical simulations, we obtain the current average velocity. The current reversals and the absolute negative mobility are presented. The increasing of the deformation of the potential can cause the absolute negative mobility to be suppressed and even disappear. When the static force is small, the increase of the potential deformation suppresses the absolute negative mobility. When the force is large, the absolute negative mobility disappears. In particular, when the potential deformation is equal to 0.015, the two current reversals present with the increasing of the force. Remarkably, when the potential deformation is small, there are three current reversals with the increasing of the friction coefficient and the average velocity presents a oscillation behavior. Supported in part by the National Natural Science Foundation of China under Grant Nos. 11575064 and 11175067, and the Natural Science Foundation of Guangdong Province under Grant No. 2016A030313433

  4. [Optimize dropping process of Ginkgo biloba dropping pills by using design space approach].

    Science.gov (United States)

    Shen, Ji-Chen; Wang, Qing-Qing; Chen, An; Pan, Fang-Lai; Gong, Xing-Chu; Qu, Hai-Bin

    2017-07-01

    In this paper, a design space approach was applied to optimize the dropping process of Ginkgo biloba dropping pills. Firstly, potential critical process parameters and potential process critical quality attributes were determined through literature research and pre-experiments. Secondly, experiments were carried out according to Box-Behnken design. Then the critical process parameters and critical quality attributes were determined based on the experimental results. Thirdly, second-order polynomial models were used to describe the quantitative relationships between critical process parameters and critical quality attributes. Finally, a probability-based design space was calculated and verified. The verification results showed that efficient production of Ginkgo biloba dropping pills can be guaranteed by operating within the design space parameters. The recommended operation ranges for the critical dropping process parameters of Ginkgo biloba dropping pills were as follows: dropping distance of 5.5-6.7 cm, and dropping speed of 59-60 drops per minute, providing a reference for industrial production of Ginkgo biloba dropping pills. Copyright© by the Chinese Pharmaceutical Association.

  5. Observation of negative potential depression on double layer during a phase of current disruption

    International Nuclear Information System (INIS)

    Fujita, H.; Matsuo, K.; Yagura, S.

    1984-01-01

    The negative potential depression with a depth of approximately electron temperature is observed on the low potential tail of the double layer just at the moment when the electron current passing through the layer is disrupted. The depression is confirmed to serve as an electron thermal barrier and form an ion hole from phase-space measurements of electrons and ions, respectively. The depth of the depression becomes maximum when the density around the depression becomes most inhomogeneous. (author)

  6. Josephson-like currents in graphene for arbitrary time-dependent potential barriers

    OpenAIRE

    Savel'ev, Sergey E.; Hausler, Wolfgang; Hanggi, Peter

    2011-01-01

    From the exact solution of the Dirac-Weyl equation we find unusual currents j_y running in y-direction parallel to a time-dependent scalar potential barrier W(x,t) placed upon a monolayer of graphene, even for vanishing momentum component p_y. In their sine-like dependence on the phase difference of wave functions, describing left and right moving Dirac fermions, these currents resemble Josephson currents in superconductors, including the occurance of Shapiro steps at certain frequencies of p...

  7. Assessment of Energy Production Potential from Ocean Currents along the United States Coastline

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Kevin A. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2013-10-03

    Increasing energy consumption and depleting reserves of fossil fuels have resulted in growing interest in alternative renewable energy from the ocean. Ocean currents are an alternative source of clean energy due to their inherent reliability, persistence and sustainability. General ocean circulations exist in the form of large rotating ocean gyres, and feature extremely rapid current flow in the western boundaries due to the Coriolis Effect. The Gulf Stream system is formed by the western boundary current of the North Atlantic Ocean that flows along the east coastline of the United States, and therefore is of particular interest as a potential energy resource for the United States.

  8. Impact of granular drops

    KAUST Repository

    Marston, J. O.

    2013-07-15

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  9. Impact of granular drops

    KAUST Repository

    Marston, J. O.; Mansoor, Mohammad M.; Thoroddsen, Sigurdur T

    2013-01-01

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  10. Preliminary determination of the energy potential of ocean currents along the southern coast of Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Andrea; Beluco, Alexandre; de Almeida, Luiz Emilio B. [Inst. Pesquisas Hidraulicas, Univ. Fed Rio Grande do Sul, Porto Alegre (Brazil)

    2013-07-01

    The ocean can be a strategic alternative for obtaining energy supplies, both from ocean waves as from sea currents and tides. Among these features, the power generation projects based on ocean currents are still under development. Generating energy from ocean can have great impact on the Brazilian energy grid, since Brazil has a vast coastline, with more than 9,000 km long, with potential for generating energy from ocean currents not fully estimated. This article presents a preliminary determination of the energy potential for power generation from ocean currents along the coast of Rio Grande do Sul, the southernmost state of Brazil, and also presents notes that contribute to the characterization of the system of ocean currents in the region. The data used were obtained in two areas near Tramandai, allowing the determination of velocities and directions of the currents on a seasonal basis. The maximum speeds obtained rarely exceed 0.750 m/s, while the average speeds do not exceed 0.200 m/s. A relationship with the prevailing winds in the region was identified. Unfortunately, the results do not allow optimism about the power generation from ocean currents on the southern coast of Brazil, at least over the continental shelf.

  11. Action potential bursts in central snail neurons elicited by paeonol: roles of ionic currents

    Science.gov (United States)

    Chen, Yi-hung; Lin, Pei-lin; Hsu, Hui-yu; Wu, Ya-ting; Yang, Han-yin; Lu, Dah-yuu; Huang, Shiang-suo; Hsieh, Ching-liang; Lin, Jaung-geng

    2010-01-01

    Aim: To investigate the effects of 2′-hydroxy-4′-methoxyacetophenone (paeonol) on the electrophysiological behavior of a central neuron (right parietal 4; RP4) of the giant African snail (Achatina fulica Ferussac). Methods: Intracellular recordings and the two-electrode voltage clamp method were used to study the effects of paeonol on the RP4 neuron. Results: The RP4 neuron generated spontaneous action potentials. Bath application of paeonol at a concentration of ≥500 μmol/L reversibly elicited action potential bursts in a concentration-dependent manner. Immersing the neurons in Co2+-substituted Ca2+-free solution did not block paeonol-elicited bursting. Pretreatment with the protein kinase A (PKA) inhibitor KT-5720 or the protein kinase C (PKC) inhibitor Ro 31-8220 did not affect the action potential bursts. Voltage-clamp studies revealed that paeonol at a concentration of 500 μmol/L had no remarkable effects on the total inward currents, whereas paeonol decreased the delayed rectifying K+ current (IKD) and the fast-inactivating K+ current (IA). Application of 4-aminopyridine (4-AP 5 mmol/L), an inhibitor of IA, or charybdotoxin 250 nmol/L, an inhibitor of the Ca2+-activated K+ current (IK(Ca)), failed to elicit action potential bursts, whereas tetraethylammonium chloride (TEA 50 mmol/L), an IKD blocker, successfully elicited action potential bursts. At a lower concentration of 5 mmol/L, TEA facilitated the induction of action potential bursts elicited by paeonol. Conclusion: Paeonol elicited a bursting firing pattern of action potentials in the RP4 neuron and this activity relates closely to the inhibitory effects of paeonol on the IKD. PMID:21042287

  12. Cell-type-dependent action potentials and voltage-gated currents in mouse fungiform taste buds.

    Science.gov (United States)

    Kimura, Kenji; Ohtubo, Yoshitaka; Tateno, Katsumi; Takeuchi, Keita; Kumazawa, Takashi; Yoshii, Kiyonori

    2014-01-01

    Taste receptor cells fire action potentials in response to taste substances to trigger non-exocytotic neurotransmitter release in type II cells and exocytotic release in type III cells. We investigated possible differences between these action potentials fired by mouse taste receptor cells using in situ whole-cell recordings, and subsequently we identified their cell types immunologically with cell-type markers, an IP3 receptor (IP3 R3) for type II cells and a SNARE protein (SNAP-25) for type III cells. Cells not immunoreactive to these antibodies were examined as non-IRCs. Here, we show that type II cells and type III cells fire action potentials using different ionic mechanisms, and that non-IRCs also fire action potentials with either of the ionic mechanisms. The width of action potentials was significantly narrower and their afterhyperpolarization was deeper in type III cells than in type II cells. Na(+) current density was similar in type II cells and type III cells, but it was significantly smaller in non-IRCs than in the others. Although outwardly rectifying current density was similar between type II cells and type III cells, tetraethylammonium (TEA) preferentially suppressed the density in type III cells and the majority of non-IRCs. Our mathematical model revealed that the shape of action potentials depended on the ratio of TEA-sensitive current density and TEA-insensitive current one. The action potentials of type II cells and type III cells under physiological conditions are discussed. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  13. THE MATHEMATIC MODEL OF POTENTIAL RELAXATION IN COULOSTATIC CONDITIONS FOR LIMITING DIFFUSION CURRENT CASE

    Directory of Open Access Journals (Sweden)

    O. H. Kapitonov

    2010-05-01

    Full Text Available A mathematical model of coulostatic relaxation of the potential for solid metallic electrode was presented. The solution in the case of limiting diffusion current was obtained. On the basis of this model the technique of concentration measurements for heavy metal ions in diluted solutions was suggested. The model adequacy was proved by experimental data.

  14. Cultural landscapes as heritage in Malaysia: Potentials, threats, and current practices

    NARCIS (Netherlands)

    Ahmad, R.

    2013-01-01

    The rural cultural landscape in Malaysia is relatively under-researched. The current heritage practices focus on built heritage as national heritage, which implies the everyday landscapes of the rural areas have been neglected as potential heritage and have received little attention from politicians

  15. A Comparative Study of Current and Potential Users of Mobile Payment Services

    Directory of Open Access Journals (Sweden)

    Chanchai Phonthanukitithaworn

    2016-11-01

    Full Text Available Previous studies of mobile payment (m-payment services have primarily focused on a single group of adopters. This study identifies the factors that influence an individual’s intention to use m-payment services and compares groups of current users (adopters with potential users (non-adopters. A research model that reflects the behavioral intention to use m-payment services is developed and empirically tested using structural equation modeling on a data set consisting of 529 potential users and 256 current users of m-payment services in Thailand. The results show that the factors that influence current users’ intentions to use m-payment services are compatibility, subjective norms, perceived trust, and perceived cost. Subjective norms, compatibility, ease of use, and perceived risk influenced potential users’ intentions to use m-payment. Subjective norms and perceived risk had a stronger influence on potential users, while perceived cost had a stronger influence on current users, in terms of their intentions to use m-payment services. Discussions, limitations, and recommendations for future research are addressed.

  16. The current and potential contribution of home-grown vegetables to ...

    African Journals Online (AJOL)

    In this paper the current and potential utilisation of crops (bought and home produce) in diets in South Africa is reviewed. Available data shows that at all levels, national, household and individual, the amounts of fruits and vegetables available and consumed are about half the WHO (2003) recommendations of at least 400g ...

  17. Head in the Clouds: A Review of Current and Future Potential for Cloud-Enabled Pedagogies

    Science.gov (United States)

    Stevenson, Michael; Hedberg, John G.

    2011-01-01

    This paper reviews the research on the disruptive and transformative potential of newly-emerging cloud-based pedagogies. It takes into consideration the extent to which Cloud Computing can be leveraged to disseminate and scale web-based applications within and across learning contexts. It examines ideas from current literature in Web 2.0- and…

  18. Assessing Lebanon's wildfire potential in association with current and future climatic conditions

    Science.gov (United States)

    George H. Mitri; Mireille G. Jazi; David McWethy

    2015-01-01

    The increasing occurrence and extent of large-scale wildfires in the Mediterranean have been linked to extended periods of warm and dry weather. We set out to assess Lebanon's wildfire potential in association with current and future climatic conditions. The Keetch-Byram Drought Index (KBDI) was the primary climate variable used in our evaluation of climate/fire...

  19. Shared Solar. Current Landscape, Market Potential, and the Impact of Federal Securities Regulation

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Brockway, Anna M. [U.S. Department of Energy, Washington, DC (United States); Ulrich, Elaine [U.S. Department of Energy, Washington, DC (United States); Margolis, Robert [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-04-07

    This report provides a high-level overview of the current U.S. shared solar landscape, the impact that a given shared solar program’s structure has on requiring federal securities oversight, as well as an estimate of market potential for U.S. shared solar deployment.

  20. Shared Solar. Current Landscape, Market Potential, and the Impact of Federal Securities Regulation

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brockway, Anna M. [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Ulrich, Elaine [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-04-01

    This report provides a high-level overview of the current U.S. shared solar landscape and the impact that a given shared solar program’s structure has on requiring federal securities oversight, as well as an estimate of market potential for U.S. shared solar deployment.

  1. Current Animal Models of Postoperative Spine Infection and Potential Future Advances

    Directory of Open Access Journals (Sweden)

    Alexandra eStavrakis

    2015-05-01

    Full Text Available Implant related infection following spine surgery is a devastating complication for patients and can potentially lead to significant neurological compromise, disability, morbidity, and even mortality. This paper provides an overview of the existing animal models of postoperative spine infection and highlights the strengths and weaknesses of each model. In addition there is discussion regarding potential modifications to these animal models to better evaluate preventative and treatment strategies for this challenging complication. Current models are effective in simulating surgical procedures but fail to evaluate infection longitudinally using multiple techniques. Potential future modifications to these models include using advanced imaging technologies to evaluate infection, use of bioluminescent bacterial species, and testing of novel treatment strategies against multiple bacterial strains. There is potential to establish a postoperative spine infection model using smaller animals, such as mice, as these would be a more cost-effective screening tool for potential therapeutic interventions.

  2. Two secondary drops

    Indian Academy of Sciences (India)

    Figure shows formation of two secondary drops of unequal size and their merger. The process is same as the earlier process until t= 0.039 Tc with necking occurring at two places, one at the bottom of the column and the other at the middle. The necking at the middle of the liquid column is due to Raleigh instability.

  3. Lambda-dropping

    DEFF Research Database (Denmark)

    Danvy, Olivier; Schultz, Ulrik Pagh

    1997-01-01

    Lambda-lifting a functional program transforms it into a set of recursive equations. We present the symmetric transformation: lambda-dropping. Lambda-dropping a set of recursive equations restores block structure and lexical scope.For lack of scope, recursive equations must carry around all...... the parameters that any of their callees might possibly need. Both lambda-lifting and lambda-dropping thus require one to compute a transitive closure over the call graph:• for lambda-lifting: to establish the Def/Use path of each free variable (these free variables are then added as parameters to each...... of the functions in the call path);• for lambda-dropping: to establish the Def/Use path of each parameter (parameters whose use occurs in the same scope as their definition do not need to be passed along in the call path).Without free variables, a program is scope-insensitive. Its blocks are then free...

  4. Current and potential sustainable corn stover feedstock for biofuel production in the United States

    Science.gov (United States)

    Tan, Zhengxi; Liu, Shu-Guang; Tieszen, Larry L.; Bliss, Norman

    2012-01-01

    Increased demand for corn (Zea mays L.) stover as a feedstock for cellulosic ethanol raises concerns about agricultural sustainability. Excessive corn stover harvesting could have long-term impacts on soil quality. We estimated current and future stover production and evaluated the potential harvestable stover amount (HSA) that could be used for biofuel feedstock in the United States by defining the minimum stover requirement (MSR) associated with the current soil organic carbon (SOC) content, tillage practices, and crop rotation systems. Here we show that the magnitude of the current HSA is limited (31 Tg y−1, dry matter) due to the high MSR for maintaining the current SOC content levels of soils that have a high carbon content. An alternative definition of MSR for soils with a moderate level of SOC content could significantly elevate the annual HSA to 68.7 Tg, or even to 132.2 Tg if the amount of currently applied manure is counted to partially offset the MSR. In the future, a greater potential for stover feedstock could come from an increase in stover yield, areal harvest index, and/or the total planted area. These results suggest that further field experiments on MSR should be designed to identify differences in MSR magnitude between maintaining SOC content and preventing soil erosion, and to understand the role of current SOC content level in determining MSR from soils with a wide range of carbon contents and climatic conditions.

  5. Study of local currents in low dimension materials using complex injecting potentials

    Science.gov (United States)

    He, Shenglai; Covington, Cody; Varga, Kálmán

    2018-04-01

    A complex potential is constructed to inject electrons into the conduction band, mimicking electron currents in nanoscale systems. The injected electrons are time propagated until a steady state is reached. The local current density can then be calculated to show the path of the conducting electrons on an atomistic level. The method allows for the calculation of the current density vectors within the medium as a function of energy of the conducting electron. Using this method, we investigate the electron pathway of graphene nanoribbons in various structures, molecular junctions, and black phosphorus nanoribbons. By analyzing the current flow through the structures, we find strong dependence on the structural geometry and the energy of the injected electrons. This method may be of general use in the study of nano-electronic materials and interfaces.

  6. Field-aligned current density versus electric potential characteristics for magnetospheric flux tubes

    International Nuclear Information System (INIS)

    Lemaire, J.; Scherer, M.

    1983-01-01

    The field-aligned current density (Jsub(tot)) is a non-linear function of the applied potential difference (phi) between the ionosphere and the magnetosphere. This nonlinear function has been calculated for plasma boundary conditions typical in a dayside cusp magnetic flux tube. The J-characteristic of such a flux tube changes when the temperatures of the warm magnetospheric electrons and of the cold ionospheric electrons are modified; it changes also when the relative density of the warm plasma is modified; the presence of trapped secondary electrons changes also the J-characteristic. The partial currents contributed by the warm and cold electrons, and by warm and cold ions are illustrated. The dynamic characteristic of an electric circuit depends on the static characteristic of each component of the sytem: i.e. the resistive ionosphere, the return current region, and the region of particle precipitation whose field-aligned current/voltage characteristics have been studied in this article

  7. Multifunctional nanopipette for simultaneous ionic current and potential detection of nanoparticles

    Science.gov (United States)

    Panday, Namuna; He, Jin

    Nanopipette has been demonstrated as a nanopore type biosensor for DNA, protein, nanoparticle and virus analysis. In the last two decades, nanopore based technologies have made remarkable progress for single entity detection and analysis. Multifunctional nanopipette for multi-parameter detection is a new trend for nanopore based technique. We have developed a technique to fabricate multifunctional nanopipette which contains both nanopore and carbon nanoelectrode (CNE) at the nanopipette tip. It can be quickly, cheaply and reproducibly fabricated from theta pipettes. We have been able to use this multifunctional nanopieptte for simultaneous detection of ionic current and local electrical potential changes during translocation of charged gold nanoparticles (GNPs) which is used as a model experiment. The CNE functions as a local potential probe. We have demonstrated that it can detect the local potential change during translocation of a single GNP as well as collective potential change due to cluster of GNPs outside the nanopore entrance. From the potential change, we can also have insight of motion of GNPs before entering the nanopore. We have also tested insulating and biological NPs with various size and charge. Observed results have shown correlations between ionic current and potential change during translocation of these NPs. Florida International University.

  8. Potential effects of climate change on a marine invasion: The importance of current context

    Directory of Open Access Journals (Sweden)

    Isabelle M. CÔTÉ, Stephanie J. GREEN

    2012-02-01

    Full Text Available Species invasions threaten marine biodiversity globally. There is a concern that climate change is exacerbating this problem. Here, we examined some of the potential effects of warming water temperatures on the invasion of Western Atlantic habitats by a marine predator, the Indo-Pacific lionfish (Pterois volitans and P. miles. We focussed on two temperature-dependent aspects of lionfish life-history and behaviour: pelagic larval duration, because of its link to dispersal potential, and prey consumption rate, because it is an important determinant of the impacts of lionfish on native prey. Using models derived from fundamental metabolic theory, we predict that the length of time spent by lionfish in the plankton in early life should decrease with warming temperatures, with a concomitant reduction in potential dispersal distance. Although the uncertainty around change in dispersal distances is large, predicted reductions are, on average, more than an order of magnitude smaller than the current rate of range expansion of lionfish in the Caribbean. Nevertheless, because shorter pelagic larval duration has the potential to increase local retention of larvae, local lionfish management will become increasingly important under projected climate change. Increasing temperature is also expected to worsen the current imbalance between rates of prey consumption by lionfish and biomass production by their prey, leading to a heightened decline in native reef fish biomass. However, the magnitude of climate-induced decline is predicted to be minor compared to the effect of current rates of lionfish population increases (and hence overall prey consumption rates on invaded reefs. Placing the predicted effects of climate change in the current context thus reveals that, at least for the lionfish invasion, the threat is clear and present, rather than future [Current Zoology 58 (1: 1–8, 2012].

  9. A mix-and-read drop-based in vitro two-hybrid method for screening high-affinity peptide binders

    Science.gov (United States)

    Cui, Naiwen; Zhang, Huidan; Schneider, Nils; Tao, Ye; Asahara, Haruichi; Sun, Zhiyi; Cai, Yamei; Koehler, Stephan A.; de Greef, Tom F. A.; Abbaspourrad, Alireza; Weitz, David A.; Chong, Shaorong

    2016-01-01

    Drop-based microfluidics have recently become a novel tool by providing a stable linkage between phenotype and genotype for high throughput screening. However, use of drop-based microfluidics for screening high-affinity peptide binders has not been demonstrated due to the lack of a sensitive functional assay that can detect single DNA molecules in drops. To address this sensitivity issue, we introduced in vitro two-hybrid system (IVT2H) into microfluidic drops and developed a streamlined mix-and-read drop-IVT2H method to screen a random DNA library. Drop-IVT2H was based on the correlation between the binding affinity of two interacting protein domains and transcriptional activation of a fluorescent reporter. A DNA library encoding potential peptide binders was encapsulated with IVT2H such that single DNA molecules were distributed in individual drops. We validated drop-IVT2H by screening a three-random-residue library derived from a high-affinity MDM2 inhibitor PMI. The current drop-IVT2H platform is ideally suited for affinity screening of small-to-medium-sized libraries (103–106). It can obtain hits within a single day while consuming minimal amounts of reagents. Drop-IVT2H simplifies and accelerates the drop-based microfluidics workflow for screening random DNA libraries, and represents a novel alternative method for protein engineering and in vitro directed protein evolution. PMID:26940078

  10. MHD Equilibrium with Reversed Current Density and Magnetic Islands Revisited: the Vacuum Vector Potential Calculus

    Science.gov (United States)

    L. Braga, F.

    2013-10-01

    The solution of Grad-Shafranov equation determines the stationary behavior of fusion plasma inside a tokamak. To solve the equation it is necessary to know the toroidal current density profile. Recent works show that it is possible to determine a magnetohydrodynamic (MHD) equilibrium with reversed current density (RCD) profiles that presents magnetic islands. In this work we show analytical MHD equilibrium with a RCD profile and analyze the structure of the vacuum vector potential associated with these equilibria using the virtual casing principle.

  11. An induced current method for measuring zeta potential of electrolyte solution-air interface.

    Science.gov (United States)

    Song, Yongxin; Zhao, Kai; Wang, Junsheng; Wu, Xudong; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

    2014-02-15

    This paper reports a novel and very simple method for measuring the zeta potential of electrolyte solution-air interface. When a measuring electrode contacts the electrolyte solution-air interface, an electrical current will be generated due to the potential difference between the electrode-air surface and the electrolyte solution-air interface. The amplitude of the measured electric signal is linearly proportional to this potential difference; and depends only on the zeta potential at the electrolyte solution-air interface, regardless of the types and concentrations of the electrolyte. A correlation between the zeta potential and the measured voltage signal is obtained based on the experimental data. Using this equation, the zeta potential of any electrolyte solution-air interface can be evaluated quickly and easily by inserting an electrode through the electrolyte solution-air interface and measuring the electrical signal amplitude. This method was verified by comparing the obtained results of NaCl, MgCl2 and CaCl2 solutions of different pH values and concentrations with the zeta potential data reported in the published journal papers. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. A new method for the compensation of ohmic drop in galvanic cells

    NARCIS (Netherlands)

    Kooijman, D.J.; Sluyters, J.H.

    Generally the ohmic potential drop in a galvanic cell that occurs if a rectangular pulse is led through the cell, is compensated by means of a well-known bridge circuit. A better method making use of a phase reverter is described and its features are discussed. Exchange current densities up to 1200

  13. Monitoring of crack growth and crack mouth opening displacement in compact tension specimens at high temperatures : Development and implementation of the Direct Current Potential Drop (DCPD) method

    OpenAIRE

    Malmqvist, Philip

    2016-01-01

    The mechanical engineering department at the University of Idaho is conducting a project with the purpose of developing a complete system for investigating creep-, creep-fatigue- and fatigue properties of metallic materials at elevated temperatures up to 650 ˚C with Compact Tension (CT) specimens. Considerable efforts have been made to study and understand these phenomena, although numerous problems still exist. It is important to explore more extensively the complicated phenomena of creep, f...

  14. Mexican plums (Spondias spp.): their current distribution and potential distribution under climate change scenarios for Mexico

    OpenAIRE

    Arce-Romero, Antonio Rafael; Monterroso-Rivas, Alejandro Ismael; Gómez-Díaz, Jesús David; Cruz-León, Artemio

    2017-01-01

    Abstract Plums (Spondias spp.) are species native to Mexico with adaptive, nutritional and ethnobotanical advantages. The aim of this study was to assess the current and potential distribution of two species of Mexican plum: Spondias purpurea L. and Spondias mombin L. The method applied was ecological niche modeling in Maxent software, which has been used in Mexico with good results. In fieldwork, information on the presence of these species in the country was collected. In addition, environm...

  15. Potential scour for marine current turbines based on experience of offshore wind turbine

    International Nuclear Information System (INIS)

    Chen, L; Lam, W H; Shamsuddin, A H

    2013-01-01

    The oceans have tremendous untapped natural resources. These sources are capable to make significant contribution to our future energy demands. Marine current energy offers sustainable and renewable alternative to conventional sources. Survival problems of Marine Current Turbines (MCTs) need to be addressed due to the harsh marine environment. The analogous researches in wind turbine have been conducted. Some of the results and knowledge are transferable to marine current energy industry. There still exist some gaps in the state of knowledge. Scour around marine structures have been well recognised as an engineering issue as scour is likely to cause structural instability. This paper aims to review different types of foundation of MCTs and potential scour and scour protection around these foundations based on the experience of offshore wind turbine farm.

  16. Chaotic Dynamics of a Josephson Junction with a Ratchet Potential and Current-Modulating Damping

    Science.gov (United States)

    Li, Fei; Li, Wenwu; Xu, Lan

    2018-04-01

    The chaotic dynamics of a Josephson junction with a ratchet potential and current-modulating damping are studied. Under the first-order approximation, we construct the general solution of the first-order equation whose boundedness condition contains the famous Melnikov chaotic criterion. Based on the general solution, the incomputability and unpredictability of the system's chaotic behavior are discussed. For the case beyond perturbation conditions, the evolution of stroboscopic Poincaré sections shows that the system undergoes a quasi-periodic transition to chaos with an increasing intensity of the rf-current. Through a suitable feedback controlling strategy, the chaos can be effectively suppressed and the intensity of the controller can vary in a large range. It is also found that the current between the two separated superconductors increases monotonously in some specific parameter spaces.

  17. RF Rectification on LAPD and NSTX: the relationship between rectified currents and potentials

    Science.gov (United States)

    Perkins, R. J.; Carter, T.; Caughman, J. B.; van Compernolle, B.; Gekelman, W.; Hosea, J. C.; Jaworski, M. A.; Kramer, G. J.; Lau, C.; Martin, E. H.; Pribyl, P.; Tripathi, S. K. P.; Vincena, S.

    2017-10-01

    RF rectification is a sheath phenomenon important in the fusion community for impurity injection, hot spot formation on plasma-facing components, modifications of the scrape-off layer, and as a far-field sink of wave power. The latter is of particular concern for the National Spherical Torus eXperiment (NSTX), where a substantial fraction of the fast-wave power is lost to the divertor along scrape-off layer field lines. To assess the relationship between rectified currents and rectified voltages, detailed experiments have been performed on the Large Plasma Device (LAPD). An electron current is measured flowing out of the antenna and into the limiters, consistent with RF rectification with a higher RF potential at the antenna. The scaling of this current with RF power will be presented. The limiters are also floated to inhibit this DC current; the impact of this change on plasma-potential and wave-field measurements will be shown. Comparison to data from divertor probes in NSTX will be made. These experiments on a flexible mid-sized experiment will provide insight and guidance into the effects of ICRF on the edge plasma in larger fusion experiments. Funded by the DOE OFES (DE-FC02-07ER54918 and DE-AC02-09CH11466), NSF (NSF- PHY 1036140), and the Univ. of California (12-LR- 237124).

  18. Theoretical Analysis of Potential and Current Distributions in Planar Electrodes of Lithium-ion Batteries

    International Nuclear Information System (INIS)

    Taheri, Peyman; Mansouri, Abraham; Yazdanpour, Maryam; Bahrami, Majid

    2014-01-01

    An analytical model is proposed to describe the two-dimensional distribution of potential and current in planar electrodes of pouch-type lithium-ion batteries. A concentration-independent polarization expression, obtained experimentally, is used to mimic the electrochemical performance of the battery. By numerically solving the charge balance equation on each electrode in conjugation with the polarization expression, the battery behavior during constant-current discharge processes is simulated. Our numerical simulations show that reaction current between the electrodes remains approximately uniform during most of the discharge process, in particular, when depth-of-discharge varies from 5% to 85%. This observation suggests to simplify the electrochemical behavior of the battery such that the charge balance equation on each electrode can be solved analytically to obtain closed-form solutions for potential and current density distributions. The analytical model shows fair agreement with numerical data at modest computational cost. The model is applicable for both charge and discharge processes, and its application is demonstrated for a prismatic 20 Ah nickel-manganese-cobalt lithium-ion battery during discharge processes

  19. Evolution of ion-acoustic potential well in a current-carrying plasma

    International Nuclear Information System (INIS)

    Maslov, V.I.

    1990-01-01

    Properties and evolution of nonlinear correlated collective disturbance of potential well in current-carrying limited plasma are described. Study shows, that potential well intensifies while exchanging energy with resonance electrons reflecting from it with distribution unstable function. In this case, electron deficiency occurs ahead of the well and electron excess - behined it due to asymmetry, relatively to well velocity, of distribution function of electrons injected at boundaries, in velocity space and due to their reflection from well. Quasineutrality is reduced by self-congruent formation of potential jump within well range. With amplitude growth at its essential values the well is braked. Similar pattern of localized disturbance evolution was observed during numerical and laboratory experiments

  20. Potential Eye Drop Based on a Calix[4]arene Nanoassembly for Curcumin Delivery: Enhanced Drug Solubility, Stability, and Anti-Inflammatory Effect.

    Science.gov (United States)

    Granata, Giuseppe; Paterniti, Irene; Geraci, Corrada; Cunsolo, Francesca; Esposito, Emanuela; Cordaro, Marika; Blanco, Anna Rita; Cuzzocrea, Salvatore; Consoli, Grazia M L

    2017-05-01

    Curcumin is an Indian spice with a wide spectrum of biological and pharmacological activities but poor aqueous solubility, rapid degradation, and low bioavailability that affect medical benefits. To overcome these limits in ophthalmic application, curcumin was entrapped in a polycationic calix[4]arene-based nanoaggregate by a simple and reproducible method. The calix[4]arene-curcumin supramolecular assembly (Calix-Cur) appeared as a clear colloidal solution consisting in micellar nanoaggregates with size, polydispersity index, surface potential, and drug loading percentage meeting the requirements for an ocular drug delivery system. The encapsulation in the calix[4]arene nanoassembly markedly enhanced the solubility, reduced the degradation, and improved the anti-inflammatory effects of curcumin compared to free curcumin in both in vitro and in vivo experiments. Calix-Cur did not compromise the viability of J774A.1 macrophages and suppressed pro-inflammatory marker expression in J774A.1 macrophages subjected to LPS-induced oxidative stress. Histological and immunohistochemical analyses showed that Calix-Cur reduced signs of inflammation in a rat model of LPS-induced uveitis when topically administrated in the eyes. Overall, the results supported the calix[4]arene nanoassembly as a promising nanocarrier for delivering curcumin to anterior ocular tissues.

  1. Tunneling currents between carbon nanotubes inside the 3-dimensional potential of a dielectric matrix

    Directory of Open Access Journals (Sweden)

    M. S. Tsagarakis

    2017-07-01

    Full Text Available We have examined the tunneling currents between CNTs dispersed in a dielectric matrix as is normally the case in a tensile stress or toxic gas sensors. Due to the randomness of the immersion process the CNTs are at random angles and configurations between them, thus producing a 3-dimensional potential (3-D. We have produced a method that solves the Laplace equation for this type of problem and uses the WKB formulation to calculate the transmission coefficient between CNTs. We have then shown that the tunneling currents between a pair of CNTs depend critically on their relative angle and configuration. In particular we have shown that the tunneling currents do not occur only along a CNT tip to CNT tip configuration but other more efficient paths exist which give a current higher by two orders of magnitude from what a simple 1D theory would give. On the other hand the tunneling current between non-coplanar CNTs is negligible. We conclude that such phenomena cannot be analyzed by a simple 1-dimensional WKB theory and the percolation threshold necessary for conduction may be lower than the one such a theory would predict.

  2. Mechanisms of generation of membrane potential resonance in a neuron with multiple resonant ionic currents.

    Directory of Open Access Journals (Sweden)

    David M Fox

    2017-06-01

    Full Text Available Neuronal membrane potential resonance (MPR is associated with subthreshold and network oscillations. A number of voltage-gated ionic currents can contribute to the generation or amplification of MPR, but how the interaction of these currents with linear currents contributes to MPR is not well understood. We explored this in the pacemaker PD neurons of the crab pyloric network. The PD neuron MPR is sensitive to blockers of H- (IH and calcium-currents (ICa. We used the impedance profile of the biological PD neuron, measured in voltage clamp, to constrain parameter values of a conductance-based model using a genetic algorithm and obtained many optimal parameter combinations. Unlike most cases of MPR, in these optimal models, the values of resonant- (fres and phasonant- (fϕ = 0 frequencies were almost identical. Taking advantage of this fact, we linked the peak phase of ionic currents to their amplitude, in order to provide a mechanistic explanation the dependence of MPR on the ICa gating variable time constants. Additionally, we found that distinct pairwise correlations between ICa parameters contributed to the maintenance of fres and resonance power (QZ. Measurements of the PD neuron MPR at more hyperpolarized voltages resulted in a reduction of fres but no change in QZ. Constraining the optimal models using these data unmasked a positive correlation between the maximal conductances of IH and ICa. Thus, although IH is not necessary for MPR in this neuron type, it contributes indirectly by constraining the parameters of ICa.

  3. Analytical assessments on the potential of harnessing tidal currents for electricity generation in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Yun Seng; Koh, Siong Lee [Department of Physical Science, Electrical and Electronic Engineering, Tunku Abdul Rahman University (Malaysia)

    2010-05-15

    Malaysia is heavily dependent on fossil fuel for electricity generation. With the rapidly diminishing of its fuel reserve and the increasingly negative effects of fossil fuels to the environment, the government has begun to utilise bio-fuel and solar radiation for electricity generation. However, the potential of harnessing other renewable sources, particular ocean energy, in Malaysia has not been fully realised. Therefore, studies were carried out to identify the potential of harnessing ocean energy for electricity generation. The Princeton Ocean Model was used to create a three-dimensional numerical ocean model for Malaysia which was calibrated against measurement by a means of adjoint data assimilation approach. A set of reliable tidal speed and tidal elevation data was therefore generated to determine the types of tides available in Malaysia, the potential areas of installing marine current turbines (MCTs), the total amount of electricity to be generated by MCT, the economical viability and the environmental benefits of using MCT in Malaysia. This paper presents the findings on the studies, encompassing the technical, economical and environmental aspects of installing MCT in Malaysia. The results are critical to policy makers and the potential investors on tidal energy in Malaysia for decision making. It may also help the neighboring countries to realize the possible potential of their ocean energy for electricity generation. (author)

  4. Free drop impact analysis of shipping cask

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.; Kennedy, J.M.

    1989-01-01

    The WHAMS-2D and WHAMS-3D codes were used to analyze the dynamic response of the RAS/TREAT shielded shipping cask subjected to transient leadings for the purpose of assessing potential damage to the various components that comprise the the cask. The paper describes how these codes can be used to provide and intermediate level of detail between full three-dimensional finite element calculations and hand calculations which are cost effective for design purposes. Three free drops were adressed: (1) a thirty foot axial drop on either end; (2) a thirty foot oblique angle drop with the cask having several different orientations from the vertical with impact on the cask corner; and (3) a thirty foot side drop with simultaneous impact on the lifting trunnion and the bottom end. Results are presented for two models of the side and oblique angle drops; one model includes only the mass of the lapped sleeves of depleted uranium (DU) while the other includes the mass and stiffness of the DU. The results of the end drop analyses are given for models with and without imperfections in the cask. Comparison of the analysis to hand calculations and simplified analyses are given. (orig.)

  5. Blood drop patterns: Formation and applications.

    Science.gov (United States)

    Chen, Ruoyang; Zhang, Liyuan; Zang, Duyang; Shen, Wei

    2016-05-01

    The drying of a drop of blood or plasma on a solid substrate leads to the formation of interesting and complex patterns. Inter- and intra-cellular and macromolecular interactions in the drying plasma or blood drop are responsible for the final morphologies of the dried patterns. Changes in these cellular and macromolecular components in blood caused by diseases have been suspected to cause changes in the dried drop patterns of plasma and whole blood, which could be used as simple diagnostic tools to identify the health of humans and livestock. However, complex physicochemical driving forces involved in the pattern formation are not fully understood. This review focuses on the scientific development in microscopic observations and pattern interpretation of dried plasma and whole blood samples, as well as the diagnostic applications of pattern analysis. Dried drop patterns of plasma consist of intricate visible cracks in the outer region and fine structures in the central region, which are mainly influenced by the presence and concentration of inorganic salts and proteins during drying. The shrinkage of macromolecular gel and its adhesion to the substrate surface have been thought to be responsible for the formation of the cracks. Dried drop patterns of whole blood have three characteristic zones; their formation as functions of drying time has been reported in the literature. Some research works have applied engineering treatment to the evaporation process of whole blood samples. The sensitivities of the resultant patterns to the relative humidity of the environment, the wettability of the substrates, and the size of the drop have been reported. These research works shed light on the mechanisms of spreading, evaporation, gelation, and crack formation of the blood drops on solid substrates, as well as on the potential applications of dried drop patterns of plasma and whole blood in diagnosis. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  6. β1-Adrenoceptor autoantibodies affect action potential duration and delayed rectifier potassium currents in guinea pigs.

    Science.gov (United States)

    Zhao, Yuhui; Huang, Haixia; Du, Yunhui; Li, Xiao; Lv, Tingting; Zhang, Suli; Wei, Hua; Shang, Jianyu; Liu, Ping; Liu, Huirong

    2015-01-01

    β1-Adrenoceptor autoantibodies (β1-AAs) affect the action potential duration (APD) in cardiomyocytes and are related to ventricular arrhythmias. The delayed rectifier potassium current (I K) plays a crucial role in APD, but the effects of β1-AAs on I K have not been completely illuminated. This work aimed to observe the effects of β1-AAs on I K and APD and further explore the mechanisms of β1-AA-mediated ventricular arrhythmias. β1-AAs were obtained from sera of patients with coronary heart disease (CHD) and nonsustained ventricular tachycardia. With whole-cell patch clamp technique, action potentials and I K were recorded. The results illustrated 0.1 μmol/L β1-AAs shortened APD at 50 % (APD50) and 90 % (APD90) of the repolarization. However, at 0.01 μmol/L, β1-AAs had no effects on either APD90 or APD50 (P > 0.05). At 0.001 μmol/L, β1-AAs significantly prolonged APD90 and APD50. Moreover, β1-AAs (0.001, 0.01, 0.1 μmol/L) dose-dependently increased the rapidly activating delayed rectifier potassium current (I Kr), but similarly decreased the slowly activating delayed rectifier potassium current (I Ks) and increased L-type calcium currents at the different concentrations. Taken together, the IKr increase induced by high β1-AA concentrations is responsible for a significant APD reduction which would contribute to repolarization changes and trigger the malignant ventricular arrhythmias in CHD patients.

  7. Current State-of-the-Art MRI for Comprehensive Evaluation of Potential Living Liver Donors.

    Science.gov (United States)

    Jhaveri, Kartik S; Guo, Lijun; Guimarães, Luís

    2017-07-01

    This review focuses on the role of state-of-the-art MRI-based techniques for comprehensive evaluation of living donors providing single-visit assessment of the liver vasculature via MR angiography, of the biliary tract via conventional T2-weighted MR cholangiography and T1-weighted gadoxetate disodium-enhanced MR cholangiography, and of hepatic steatosis via T2*-corrected multiecho chemical shift-based water-fat separation MRI and high-speed T2-corrected multiecho MR spectroscopy. By using current state-of-the-art techniques, MRI can provide a one-stop-shop method for evaluation of the potential living liver donors.

  8. Bone Marrow Stem Cell Derived Paracrine Factors for Regenerative Medicine: Current Perspectives and Therapeutic Potential

    Directory of Open Access Journals (Sweden)

    Tom J. Burdon

    2011-01-01

    Full Text Available During the past several years, there has been intense research in the field of bone marrow-derived stem cell (BMSC therapy to facilitate its translation into clinical setting. Although a lot has been accomplished, plenty of challenges lie ahead. Furthermore, there is a growing body of evidence showing that administration of BMSC-derived conditioned media (BMSC-CM can recapitulate the beneficial effects observed after stem cell therapy. BMSCs produce a wide range of cytokines and chemokines that have, until now, shown extensive therapeutic potential. These paracrine mechanisms could be as diverse as stimulating receptor-mediated survival pathways, inducing stem cell homing and differentiation or regulating the anti-inflammatory effects in wounded areas. The current review reflects the rapid shift of interest from BMSC to BMSC-CM to alleviate many logistical and technical issues regarding cell therapy and evaluates its future potential as an effective regenerative therapy.

  9. Proton therapy for head and neck cancer: Rationale, potential indications, practical considerations, and current clinical evidence

    International Nuclear Information System (INIS)

    Mendenhall, Nancy P.; Malyapa, Robert S.; Su, Zhong; Yeung, Daniel; Mendenhall, William M.; Li, Zuofeng

    2011-01-01

    There is a strong rationale for potential benefits from proton therapy (PT) for selected cancers of the head and neck because of the opportunity to improve the therapeutic ratio by improving radiation dose distributions and because of the significant differences in radiation dose distribution achievable with x-ray-based radiation therapy (RT) and PT. Comparisons of dose distributions between x-ray-based and PT plans in selected cases show specific benefits in dose distribution likely to translate into improved clinical outcomes. However, the use of PT in head and neck cancers requires special considerations in the simulation and treatment planning process, and currently available PT technology may not permit realization of the maximum potential benefits of PT. To date, few clinical data are available, but early clinical experiences in sinonasal tumors in particular suggest significant improvements in both disease control and radiation-related toxicity

  10. Proton therapy for head and neck cancer: Rationale, potential indications, practical considerations, and current clinical evidence

    Energy Technology Data Exchange (ETDEWEB)

    Mendenhall, Nancy P.; Malyapa, Robert S.; Su, Zhong; Yeung, Daniel; Mendenhall, William M.; Li, Zuofeng (Univ. of Florida Proton Therapy Inst., Jacksonville, Florida (United States)), e-mail: menden@shands.ufl.edu

    2011-08-15

    There is a strong rationale for potential benefits from proton therapy (PT) for selected cancers of the head and neck because of the opportunity to improve the therapeutic ratio by improving radiation dose distributions and because of the significant differences in radiation dose distribution achievable with x-ray-based radiation therapy (RT) and PT. Comparisons of dose distributions between x-ray-based and PT plans in selected cases show specific benefits in dose distribution likely to translate into improved clinical outcomes. However, the use of PT in head and neck cancers requires special considerations in the simulation and treatment planning process, and currently available PT technology may not permit realization of the maximum potential benefits of PT. To date, few clinical data are available, but early clinical experiences in sinonasal tumors in particular suggest significant improvements in both disease control and radiation-related toxicity

  11. Fly ashes from coal and petroleum coke combustion: current and innovative potential applications.

    Science.gov (United States)

    González, Aixa; Navia, Rodrigo; Moreno, Natalia

    2009-12-01

    Coal fly ashes (CFA) are generated in large amounts worldwide. Current combustion technologies allow the burning of fuels with high sulfur content such as petroleum coke, generating non-CFA, such as petroleum coke fly ash (PCFA), mainly from fluidized bed combustion processes. The disposal of CFA and PCFA fly ashes can have severe impacts in the environment such as a potential groundwater contamination by the leaching of heavy metals and/or particulate matter emissions; making it necessary to treat or reuse them. At present CFA are utilized in several applications fields such as cement and concrete production, agriculture and soil stabilization. However, their reuse is restricted by the quality parameters of the end-product or requirements defined by the production process. Therefore, secondary material markets can use a limited amount of CFA, which implies the necessity of new markets for the unused CFA. Some potential future utilization options reviewed herein are zeolite synthesis and valuable metals extraction. In comparison to CFA, PCFA are characterized by a high Ca content, suggesting a possible use as neutralizers of acid wastewaters from mining operations, opening a new potential application area for PCFA that could solve contamination problems in emergent and mining countries such as Chile. However, this potential application may be limited by PCFA heavy metals leaching, mainly V and Ni, which are present in PCFA in high concentrations.

  12. Current and potential trade in horticultural products irradiated for phytosanitary purposes

    International Nuclear Information System (INIS)

    Bustos-Griffin, Emilia; Hallman, Guy J.; Griffin, Robert L.

    2012-01-01

    The current status of trade in horticultural products irradiated for phytosanitary purposes is examined, including trends, strengths and weaknesses. A strategy is proposed to take advantage of the best future opportunities for increasing trade in irradiated horticultural products by identifying best possibilities for expanding both the number and volume of commodities for irradiation and then applying appropriate business criteria in a general analysis of the commodities, commercial scenarios, and geographic regions where the greatest potential exists for expansion. The results show that fresh fruits such as mango, papaya, citrus, grapes, and vegetables such as tomatoes, onions, asparagus, garlic, and peppers from Asia and the Americas show the greatest potential. Substantial opportunities for additional growth exist, especially as regulatory conditions become more favorable. - Highlights: ► This research examined the trade in horticultural products irradiated for Phytosanitary purposes. ► Paper describes strategies for enhancing trade in irradiated horticultural products. ► Results identify commodities and regions with the greatest potential. ► Additional growth potential exists, especially as regulatory conditions become more favorable.

  13. Experimental characterization of MHD pressure drop of liquid sodium flow under uniform magnetic field

    International Nuclear Information System (INIS)

    Kim, Hee Reyoung; Park, Jon Ho; Kim, Jong Man; Nam, Ho Yoon; Choi, Jong Hyun

    2001-01-01

    Magnetic field has many effects on the hydraulic pressure drop of fluids with high electrical conductivity. The theoretical solution about MHD pressure drop is sought for the uniform current density model with simplified physical geometry. Using the MHD equation in the rectangular duct of the sodium liquid flow under a transverse magnetic field, the electrical potential is sought in terms of the duct geometry and the electrical parameters of the liquid metal and duct material. By the product of the induced current inside the liquid metal and transverse magnetic field, the pressure gradients is found as a function of the duct size and the electrical conductivity of the liquid metal. The theoretically predicted pressure drop is compared with experimental results on the change of flow velocity and magnetic flux density

  14. Nonequivalence of the magnetostatic potential energy corresponding to the Ampère and Grassmann current element force formulas

    International Nuclear Information System (INIS)

    Minteer, Timothy M

    2013-01-01

    The equivalence of the Ampère and Grassmann (Biot–Savart/Lorentz) current element force formulas is well established. However, when the magnetostatic potential energy corresponding to these force formulas is evaluated, the formulas are found to be nonequivalent. The historical current element force formulas are first presented. The magnetostatic potential energy corresponding to these historical current element force formulas are then analysed. The end result establishes the Grassmann and Neumann current element force formulas as the only commonly referenced formulas giving the correct magnetostatic potential energy for circuital currents. (paper)

  15. Drop jumping. II. The influence of dropping height on the biomechanics of drop jumping

    NARCIS (Netherlands)

    Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    In the literature, athletes preparing for explosive activities are recommended to include drop jumping in their training programs. For the execution of drop jumps, different techniques and different dropping heights can be used. This study was designed to investigate for the performance of bounce

  16. Controlling charge on levitating drops.

    Science.gov (United States)

    Hilger, Ryan T; Westphall, Michael S; Smith, Lloyd M

    2007-08-01

    Levitation technologies are used in containerless processing of materials, as microscale manipulators and reactors, and in the study of single drops and particles. Presented here is a method for controlling the amount and polarity of charge on a levitating drop. The method uses single-axis acoustic levitation to trap and levitate a single, initially neutral drop with a diameter between 400 microm and 2 mm. This drop is then charged in a controllable manner using discrete packets of charge in the form of charged drops produced by a piezoelectric drop-on-demand dispenser equipped with a charging electrode. The magnitude of the charge on the dispensed drops can be adjusted by varying the voltage applied to the charging electrode. The polarity of the charge on the added drops can be changed allowing removal of charge from the trapped drop (by neutralization) and polarity reversal. The maximum amount of added charge is limited by repulsion of like charges between the drops in the trap. This charging scheme can aid in micromanipulation and the study of charged drops and particles using levitation.

  17. Acoustic Noise Alters Selective Attention Processes as Indicated by Direct Current (DC Brain Potential Changes

    Directory of Open Access Journals (Sweden)

    Karin Trimmel

    2014-09-01

    Full Text Available Acoustic environmental noise, even of low to moderate intensity, is known to adversely affect information processing in animals and humans via attention mechanisms. In particular, facilitation and inhibition of information processing are basic functions of selective attention. Such mechanisms can be investigated by analyzing brain potentials under conditions of externally directed attention (intake of environmental information versus internally directed attention (rejection of environmental stimuli and focusing on memory/planning processes. This study investigated brain direct current (DC potential shifts—which are discussed to represent different states of cortical activation—of tasks that require intake and rejection of environmental information under noise. It was hypothesized that without background noise rejection tasks would show more positive DC potential changes compared to intake tasks and that under noise both kinds of tasks would show positive DC shifts as an expression of cortical inhibition caused by noise. DC potential shifts during intake and rejection tasks were analyzed at 16 standard locations in 45 persons during irrelevant speech or white noise vs. control condition. Without noise, rejection tasks were associated with more positive DC potential changes compared to intake tasks. During background noise, however, this difference disappeared and both kinds of tasks led to positive DC shifts. Results suggest—besides some limitations—that noise modulates selective attention mechanisms by switching to an environmental information processing and noise rejection mode, which could represent a suggested “attention shift”. Implications for fMRI studies as well as for public health in learning and performance environments including susceptible persons are discussed.

  18. Acoustic noise alters selective attention processes as indicated by direct current (DC) brain potential changes.

    Science.gov (United States)

    Trimmel, Karin; Schätzer, Julia; Trimmel, Michael

    2014-09-26

    Acoustic environmental noise, even of low to moderate intensity, is known to adversely affect information processing in animals and humans via attention mechanisms. In particular, facilitation and inhibition of information processing are basic functions of selective attention. Such mechanisms can be investigated by analyzing brain potentials under conditions of externally directed attention (intake of environmental information) versus internally directed attention (rejection of environmental stimuli and focusing on memory/planning processes). This study investigated brain direct current (DC) potential shifts-which are discussed to represent different states of cortical activation-of tasks that require intake and rejection of environmental information under noise. It was hypothesized that without background noise rejection tasks would show more positive DC potential changes compared to intake tasks and that under noise both kinds of tasks would show positive DC shifts as an expression of cortical inhibition caused by noise. DC potential shifts during intake and rejection tasks were analyzed at 16 standard locations in 45 persons during irrelevant speech or white noise vs. control condition. Without noise, rejection tasks were associated with more positive DC potential changes compared to intake tasks. During background noise, however, this difference disappeared and both kinds of tasks led to positive DC shifts. Results suggest-besides some limitations-that noise modulates selective attention mechanisms by switching to an environmental information processing and noise rejection mode, which could represent a suggested "attention shift". Implications for fMRI studies as well as for public health in learning and performance environments including susceptible persons are discussed.

  19. Pharmacological modulations of cardiac ultra-rapid and slowly activating delayed rectifier currents: potential antiarrhythmic approaches.

    Science.gov (United States)

    Islam, Mohammed A

    2010-01-01

    Despite the emerging new insights into our understandings of the cellular mechanisms underlying cardiac arrhythmia, medical therapy for this disease remains unsatisfactory. Atrial fibrillation (AF), the most prevalent arrhythmia, is responsible for significant morbidity and mortality. On the other hand, ventricular fibrillation results in sudden cardiac deaths in many instances. Prolongation of cardiac action potential (AP) is a proven principle of antiarrhythmic therapy. Class III antiarrhythmic agents prolong AP and QT interval by blocking rapidly activating delayed rectifier current (I(Kr)). However, I(Kr) blocking drugs carry the risk of life-threatening proarrhythmia. Recently, modulation of atrial-selective ultra-rapid delayed rectifier current (I(Kur)), has emerged as a novel therapeutic approach to treat AF. A number of I(Kur) blockers are being evaluated for the treatment of AF. The inhibition of slowly activating delayed rectifier current (I(Ks)) has also been proposed as an effective and safer antiarrhythmic approach because of its distinguishing characteristics that differ in remarkable ways from other selective class III agents. Selective I(Ks) block may prolong AP duration (APD) at rapid rates without leading to proarrhythmia. This article reviews the pathophysiological roles of I(Kur) and I(Ks) in cardiac repolarization and the implications of newly developed I(Kur) and I(Ks) blocking agents as promising antiarrhythmic approaches. Several recent patents pertinent to antiarrhythmic drug development have been discussed. Further research will be required to evaluate the efficacy and safety of these agents in the clinical setting.

  20. Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

    Science.gov (United States)

    Frank, A.; Heller, R.; Goldacker, W.; Kling, A.; Schmidt, C.

    2008-02-01

    Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability.

  1. Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

    International Nuclear Information System (INIS)

    Frank, A; Heller, R; Goldacker, W; Kling, A; Schmidt, C

    2008-01-01

    Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability

  2. Biphasic response of action potential duration to metabolic inhibition in rabbit and human ventricular myocytes: role of transient outward current and ATP-regulated potassium current

    NARCIS (Netherlands)

    Verkerk, A. O.; Veldkamp, M. W.; van Ginneken, A. C.; Bouman, L. N.

    1996-01-01

    Inhibition of cell metabolism is associated with significant changes in action potential duration. The aim of this study was to investigate the time course of the changes in action potential duration during metabolic inhibition and to determine what changes in membrane currents are responsible. The

  3. RAGE-dependent potentiation of TRPV1 currents in sensory neurons exposed to high glucose.

    Science.gov (United States)

    Lam, Doris; Momeni, Zeinab; Theaker, Michael; Jagadeeshan, Santosh; Yamamoto, Yasuhiko; Ianowski, Juan P; Campanucci, Verónica A

    2018-01-01

    Diabetes mellitus is associated with sensory abnormalities, including exacerbated responses to painful (hyperalgesia) or non-painful (allodynia) stimuli. These abnormalities are symptoms of diabetic peripheral neuropathy (DPN), which is the most common complication that affects approximately 50% of diabetic patients. Yet, the underlying mechanisms linking hyperglycemia and symptoms of DPN remain poorly understood. The transient receptor potential vanilloid 1 (TRPV1) channel plays a central role in such sensory abnormalities and shows elevated expression levels in animal models of diabetes. Here, we investigated the function of TRPV1 channels in sensory neurons cultured from the dorsal root ganglion (DRG) of neonatal mice, under control (5mM) and high glucose (25mM) conditions. After maintaining DRG neurons in high glucose for 1 week, we observed a significant increase in capsaicin (CAP)-evoked currents and CAP-evoked depolarizations, independent of TRPV1 channel expression. These functional changes were largely dependent on the expression of the receptor for Advanced Glycation End-products (RAGE), calcium influx, cytoplasmic ROS accumulation, PKC, and Src kinase activity. Like cultured neurons from neonates, mature neurons from adult mice also displayed a similar potentiation of CAP-evoked currents in the high glucose condition. Taken together, our data demonstrate that under the diabetic condition, DRG neurons are directly affected by elevated levels of glucose, independent of vascular or glial signals, and dependent on RAGE expression. These early cellular and molecular changes to sensory neurons in vitro are potential mechanisms that might contribute to sensory abnormalities that can occur in the very early stages of diabetes.

  4. Current and potential carbon stocks in Moso bamboo forests in China.

    Science.gov (United States)

    Li, Pingheng; Zhou, Guomo; Du, Huaqiang; Lu, Dengsheng; Mo, Lufeng; Xu, Xiaojun; Shi, Yongjun; Zhou, Yufeng

    2015-06-01

    Bamboo forests provide important ecosystem services and play an important role in terrestrial carbon cycling. Of the approximately 500 bamboo species in China, Moso bamboo (Phyllostachys pubescens) is the most important one in terms of distribution, timber value, and other economic values. In this study, we estimated current and potential carbon stocks in China's Moso bamboo forests and in their products. The results showed that Moso bamboo forests in China stored about 611.15 ± 142.31 Tg C, 75% of which was in the top 60 cm soil, 22% in the biomass of Moso bamboos, and 3% in the ground layer (i.e., bamboo litter, shrub, and herb layers). Moso bamboo products store 10.19 ± 2.54 Tg C per year. The potential carbon stocks reach 1331.4 ± 325.1 Tg C, while the potential C stored in products is 29.22 ± 7.31 Tg C a(-1). Our results indicate that Moso bamboo forests and products play a critical role in C sequestration. The information gained in this study will facilitate policy decisions concerning carbon sequestration and management of Moso bamboo forests in China. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Finite element transport methods for criticality calculations - current status and potential applications

    International Nuclear Information System (INIS)

    Oliveira, C.R.E. de; Goddard, A.

    1991-01-01

    In this paper we review the current status of the finite element method applied to the solution of the neutron transport equation and we discuss its potential role in the field of criticality safety. We show that the method's ability in handling complex, irregular geometry in two- and three-dimensions coupled with its accurate solutions potentially renders it an attractive alternative to the longer-established Monte Carlo method. Details of the most favoured form of the method - that which combines finite elements in space and spherical harmonics in angle - are presented. This form of the method, which has been extensively investigated over the last decade by research groups at the University of London, has been numerically implemented in the finite element code EVENT. The code has among its main features the capability of solving fixed source eigenvalue and time-dependent complex geometry problems in two- and three-dimensions. Other features of the code include anisotropic up- and down-scatter, direct and/or adjoint solutions and access to standard data libraries. Numerical examples, ranging from simple criticality benchmark studies to the analysis of idealised three-dimensional reactor cores, are presented to demonstrate the potential of the method. (author)

  6. Inflammatory mediators potentiate high affinity GABA(A) currents in rat dorsal root ganglion neurons.

    Science.gov (United States)

    Lee, Kwan Yeop; Gold, Michael S

    2012-06-19

    Following acute tissue injury action potentials may be initiated in afferent processes terminating in the dorsal horn of the spinal cord that are propagated back out to the periphery, a process referred to as a dorsal root reflex (DRR). The DRR is dependent on the activation of GABA(A) receptors. The prevailing hypothesis is that DRR is due to a depolarizing shift in the chloride equilibrium potential (E(Cl)) following an injury-induced activation of the Na(+)-K(+)-Cl(-)-cotransporter. Because inflammatory mediators (IM), such as prostaglandin E(2) are also released in the spinal cord following tissue injury, as well as evidence that E(Cl) is already depolarized in primary afferents, an alternative hypothesis is that an IM-induced increase in GABA(A) receptor mediated current (I(GABA)) could underlie the injury-induced increase in DRR. To test this hypothesis, we explored the impact of IM (prostaglandin E(2) (1 μM), bradykinin (10 μM), and histamine (1 μM)) on I(GABA) in dissociated rat dorsal root ganglion (DRG) neurons with standard whole cell patch clamp techniques. IM potentiated I(GABA) in a subpopulation of medium to large diameter capsaicin insensitive DRG neurons. This effect was dependent on the concentration of GABA, manifest only at low concentrations (emergence of injury-induced DRR. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  7. Soil organic carbon of an intensively reclaimed region in China: Current status and carbon sequestration potential.

    Science.gov (United States)

    Deng, Xunfei; Zhan, Yu; Wang, Fei; Ma, Wanzhu; Ren, Zhouqiao; Chen, Xiaojia; Qin, Fangjin; Long, Wenli; Zhu, Zhenling; Lv, Xiaonan

    2016-09-15

    Land reclamation has been highly intensive in China, resulting in a large amount of soil organic carbon (SOC) loss to the atmosphere. Evaluating the factors which drive SOC dynamics and carbon sequestration potential in reclaimed land is critical for improving soil fertility and mitigating global warming. This study aims to determine the current status and factors important to the SOC density in a typical reclaimed land located in Eastern China, where land reclamation has been undergoing for centuries. A total of 4746 topsoil samples were collected from 2007 to 2010. The SOC density of the reclaimed land (3.18±0.05kgCm(-2); mean±standard error) is significantly lower than that of the adjacent non-reclaimed land (5.71±0.04kgCm(-2)) (pcarbon sequestration potential of the reclaimed lands may achieve a maximum of 5.80±1.81kgCO2m(-2) (mean±SD) when dryland is converted to flooded land with vegetable-rice cropping system and soil pH of ~5.9. Note that in some scenarios the methane emission substantially offsets the carbon sequestration potential, especially for continuous rice cropping system. With the optimal setting for carbon sequestration, it is estimated that the dryland reclaimed in the last 50years in China is able to sequester 0.12milliontons CO2 equivalent per year. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Assessment of Energy Production Potential from Ocean Currents along the United States Coastline

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Kevin

    2013-09-15

    Increasing energy consumption and depleting reserves of fossil fuels have resulted in growing interest in alternative renewable energy from the ocean. Ocean currents are an alternative source of clean energy due to their inherent reliability, persistence and sustainability. General ocean circulations exist in the form of large rotating ocean gyres, and feature extremely rapid current flow in the western boundaries due to the Coriolis Effect. The Gulf Stream system is formed by the western boundary current of the North Atlantic Ocean that flows along the east coastline of the United States, and therefore is of particular interest as a potential energy resource for the United States. This project created a national database of ocean current energy resources to help advance awareness and market penetration in ocean current energy resource assessment. The database, consisting of joint velocity magnitude and direction probability histograms, was created from data created by seven years of numerical model simulations. The accuracy of the database was evaluated by ORNL?s independent validation effort documented in a separate report. Estimates of the total theoretical power resource contained in the ocean currents were calculated utilizing two separate approaches. Firstly, the theoretical energy balance in the Gulf Stream system was examined using the two-dimensional ocean circulation equations based on the assumptions of the Stommel model for subtropical gyres with the quasi-geostrophic balance between pressure gradient, Coriolis force, wind stress and friction driving the circulation. Parameters including water depth, natural dissipation rate and wind stress are calibrated in the model so that the model can reproduce reasonable flow properties including volume flux and energy flux. To represent flow dissipation due to turbines additional turbine drag coefficient is formulated and included in the model. Secondly, to determine the reasonableness of the total power

  9. First drop dissimilarity in drop-on-demand inkjet devices

    International Nuclear Information System (INIS)

    Famili, Amin; Palkar, Saurabh A.; Baldy, William J. Jr.

    2011-01-01

    As inkjet printing technology is increasingly applied in a broader array of applications, careful characterization of its method of use is critical due to its inherent sensitivity. A common operational mode in inkjet technology known as drop-on-demand ejection is used as a way to deliver a controlled quantity of material to a precise location on a target. This method of operation allows ejection of individual or a sequence (burst) of drops based on a timed trigger event. This work presents an examination of sequences of drops as they are ejected, indicating a number of phenomena that must be considered when designing a drop-on-demand inkjet system. These phenomena appear to be driven by differences between the first ejected drop in a burst and those that follow it and result in a break-down of the linear relationship expected between driving amplitude and drop mass. This first drop, as quantified by high-speed videography and subsequent image analysis, can be different in morphology, trajectory, velocity, and volume from subsequent drops within a burst. These findings were confirmed orthogonally by both volume and mass measurement techniques which allowed quantitation down to single drops.

  10. Modeling the yield potential of dryland canola under current and future climates in California

    Science.gov (United States)

    George, N.; Kaffka, S.; Beeck, C.; Bucaram, S.; Zhang, J.

    2012-12-01

    -adapted canola varieties can be justified, and the potential value of a California canola industry both now and in the future. Winter annual crops like canola use rainfall in a Mediterranean climate like California more efficiently than spring or summer crops. Our results suggest that under current production costs and seed prices, dry farmed canola will have good potential in certain areas of the California. Canola yields decline with annual winter precipitation, however economically viable yields are still achieved at relatively precipitation levels (200 mm). Results from simulation, combined with related economic modeling (reported elsewhere) suggest that canola will be viable in a variety of production systems in the northern Sacramento Valley and some coastal locations, even under drier future climate scenarios. The in-field evaluation of Australian canola varieties should contribute to maintain or improving resource use efficiency and farm profitability.

  11. Fault Current Distribution and Pole Earth Potential Rise (EPR) Under Substation Fault

    Science.gov (United States)

    Nnassereddine, M.; Rizk, J.; Hellany, A.; Nagrial, M.

    2013-09-01

    New high-voltage (HV) substations are fed by transmission lines. The position of these lines necessitates earthing design to ensure safety compliance of the system. Conductive structures such as steel or concrete poles are widely used in HV transmission mains. The earth potential rise (EPR) generated by a fault at the substation could result in an unsafe condition. This article discusses EPR based on substation fault. The pole EPR assessment under substation fault is assessed with and without mutual impedance consideration. Split factor determination with and without the mutual impedance of the line is also discussed. Furthermore, a simplified formula to compute the pole grid current under substation fault is included. Also, it includes the introduction of the n factor which determines the number of poles that required earthing assessments under substation fault. A case study is shown.

  12. Current knowledge and potential applications of cavitation technologies for the petroleum industry.

    Science.gov (United States)

    Avvaru, Balasubrahmanyam; Venkateswaran, Natarajan; Uppara, Parasuveera; Iyengar, Suresh B; Katti, Sanjeev S

    2018-04-01

    Technologies based on cavitation, produced by either ultrasound or hydrodynamic means, are part of growing literature for individual refinery unit processes. In this review, we have explained the mechanism through which these cavitation technologies intensify individual unit processes such as enhanced oil recovery, demulsification of water in oil emulsions during desalting stage, crude oil viscosity reduction, oxidative desulphurisation/demetallization, and crude oil upgrading. Apart from these refinery processes, applications of this technology are also mentioned for other potential crude oil sources such as oil shale and oil sand extraction. The relative advantages and current situation of each application/process at commercial scale is explained. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The potential of large critical currents in the high Tc oxides

    International Nuclear Information System (INIS)

    Deutcher, G.

    1993-01-01

    The potential for high critical current densities is examined. on a thermodynamical basis, the energy scale for vortex pinning can be derived for instance from a measurement of the width of the critical region. This energy scale is of the order of 0.2 eV in YBCO, which is sufficient for practical applications. Another important parameter is the short coherence length. The inner plane length, of the order of a few lattice spacing, is favorable for pinning by point defects. But the very short outer plane length gives rise to anomalous magnetic behavior, unfavorable for high-field applications at high temperature; this is true in particular in most anisotropic oxides, such as the Bi compounds (author)

  14. Improvement Strategies, Cost Effective Production, and Potential Applications of Fungal Glucose Oxidase (GOD): Current Updates.

    Science.gov (United States)

    Dubey, Manish K; Zehra, Andleeb; Aamir, Mohd; Meena, Mukesh; Ahirwal, Laxmi; Singh, Siddhartha; Shukla, Shruti; Upadhyay, Ram S; Bueno-Mari, Ruben; Bajpai, Vivek K

    2017-01-01

    Fungal glucose oxidase (GOD) is widely employed in the different sectors of food industries for use in baking products, dry egg powder, beverages, and gluconic acid production. GOD also has several other novel applications in chemical, pharmaceutical, textile, and other biotechnological industries. The electrochemical suitability of GOD catalyzed reactions has enabled its successful use in bioelectronic devices, particularly biofuel cells, and biosensors. Other crucial aspects of GOD such as improved feeding efficiency in response to GOD supplemental diet, roles in antimicrobial activities, and enhancing pathogen defense response, thereby providing induced resistance in plants have also been reported. Moreover, the medical science, another emerging branch where GOD was recently reported to induce several apoptosis characteristics as well as cellular senescence by downregulating Klotho gene expression. These widespread applications of GOD have led to increased demand for more extensive research to improve its production, characterization, and enhanced stability to enable long term usages. Currently, GOD is mainly produced and purified from Aspergillus niger and Penicillium species, but the yield is relatively low and the purification process is troublesome. It is practical to build an excellent GOD-producing strain. Therefore, the present review describes innovative methods of enhancing fungal GOD production by using genetic and non-genetic approaches in-depth along with purification techniques. The review also highlights current research progress in the cost effective production of GOD, including key advances, potential applications and limitations. Therefore, there is an extensive need to commercialize these processes by developing and optimizing novel strategies for cost effective GOD production.

  15. Marine Benthic Habitats and Seabed Suitability Mapping for Potential Ocean Current Energy Siting Offshore Southeast Florida

    Directory of Open Access Journals (Sweden)

    Amanda Mulcan

    2015-05-01

    Full Text Available This study examines the legal framework for ocean current energy policy and regulation to develop a metric for assessing the biological and geological characteristics of a seabed area with respect to the siting of OCE devices, a framework of criteria by which to assess seabed suitability (seabed suitability framework that can facilitate the siting, and implementation of ocean current energy (OCE projects. Seafloor geology and benthic biological data were analyzed in conjunction with seafloor core sample geostatistical interpolation to locate suitable substrates for OCE anchoring. Existing submarine cable pathways were considered to determine pathways for power transmission cables that circumvent biologically sensitive areas. Suitability analysis indicates that areas east of the Miami Terrace and north of recently identified deep-sea coral mounds are the most appropriate for OCE siting due to abundance of sand/sediment substrate, existing underwater cable route access, and minimal biological presence (i.e., little to no benthic communities. Further reconnaissance requires higher resolution maps of geological substrate and benthic community locations to identify specific OCE development locations, classify benthic conditions, and minimize potentially negative OCE environmental impacts.

  16. RF current distribution and topology of RF sheath potentials in front of ICRF antennae

    International Nuclear Information System (INIS)

    Colas, L.; Heuraux, S.; Bremond, S.; Bosia, G.

    2005-01-01

    The 2D (radial/poloidal) spatial topology of RF-induced convective cells developing radially in front of ion cyclotron range of frequency (ICRF) antennae is investigated, in relation to the spatial distribution of RF currents over the metallic structure of the antenna. This is done via a Green's function, determined from the ICRF wave coupling equations, and well-suited to open field lines extending toroidally far away on both sides of the antenna. Using such formalism, combined with a full-wave calculation using the 3D antenna code ICANT (Pecoul S. et al 2000 Comput. Phys. Commun. 146 166-87), two classes of convective cells are analysed. The first one appears in front of phased arrays of straps, and depending on the strap phasing, its topology is interpreted using the poloidal profiles of either the RF current or the RF voltage of the strip line theory. The other class of convective cells is specific to antenna box corners and is evidenced for the first time. Based on such analysis, general design rules are worked out in order to reduce the RF-sheath potentials, which generalize those proposed in the earlier literature, and concrete antenna design options are tested numerically. The merits of aligning all strap centres on the same (tilted) flux tube, and of reducing the antenna box toroidal conductivity in its lower and upper parts, are discussed

  17. Determining the true polarity and amplitude of synaptic currents underlying gamma oscillations of local field potentials.

    Directory of Open Access Journals (Sweden)

    Gonzalo Martín-Vázquez

    Full Text Available Fluctuations in successive waves of oscillatory local field potentials (LFPs reflect the ongoing processing of neuron populations. However, their amplitude, polarity and synaptic origin are uncertain due to the blending of electric fields produced by multiple converging inputs, and the lack of a baseline in standard AC-coupled recordings. Consequently, the estimation of underlying currents by laminar analysis yields spurious sequences of inward and outward currents. We devised a combined analytical/experimental approach that is suitable to study laminated structures. The approach was essayed on an experimental oscillatory LFP as the Schaffer-CA1 gamma input in anesthetized rats, and it was verified by parallel processing of model LFPs obtained through a realistic CA1 aggregate of compartmental units. This approach requires laminar LFP recordings and the isolation of the oscillatory input from other converging pathways, which was achieved through an independent component analysis. It also allows the spatial and temporal components of pathway-specific LFPs to be separated. While reconstructed Schaffer-specific LFPs still show spurious inward/outward current sequences, these were clearly stratified into distinct subcellular domains. These spatial bands guided the localized delivery of neurotransmitter blockers in experiments. As expected, only Glutamate but not GABA blockers abolished Schaffer LFPs when applied to the active but not passive subcellular domains of pyramidal cells. The known chemical nature of the oscillatory LFP allowed an empirical offset of the temporal component of Schaffer LFPs, such that following reconstruction they yield only sinks or sources at the appropriate sites. In terms of number and polarity, some waves increased and others decreased proportional to the concomitant inputs in native multisynaptic LFPs. Interestingly, the processing also retrieved the initiation time for each wave, which can be used to discriminate

  18. Effects of neglecting carrier tunneling on electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs

    OpenAIRE

    Hakim, MMA; Haque, A

    2002-01-01

    We investigate the validity of the assumption of neglecting carrier tunneling effects on self-consistent electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs. Comparison between simulated and experimental results shows that for accurate modeling of direct tunneling current, tunneling effects on potential profile need to be considered. The relative error in gate current due to neglecting carrier tunneling is higher at higher gate voltages and increases...

  19. Endomorphins potentiate acid-sensing ion channel currents and enhance the lactic acid-mediated increase in arterial blood pressure: effects amplified in hindlimb ischaemia.

    Science.gov (United States)

    Farrag, Mohamed; Drobish, Julie K; Puhl, Henry L; Kim, Joyce S; Herold, Paul B; Kaufman, Marc P; Ruiz-Velasco, Victor

    2017-12-01

    Chronic limb ischaemia, characterized by inflammatory mediator release and a low extracellular pH, leads to acid-sensing ion channel (ASIC) activation and reflexively increases mean arterial pressure; endomorphin release is also increased under inflammatory conditions. We examined the modulation of ASIC currents by endomorphins in sensory neurons from rats with freely perfused and ligated femoral arteries: peripheral artery disease (PAD) model. Endomorphins potentiated sustained ASIC currents in both groups of dorsal root ganglion neurons, independent of mu opioid receptor stimulation or G protein activation. Intra-arterial administration of lactic acid (to simulate exercising muscle and evoke a pressor reflex), endomorphin-2 and naloxone resulted in a significantly greater pressor response than lactic acid alone, while administration of APETx2 inhibited endomorphin's enhancing effect in both groups. These results suggest a novel role for endomorphins in modulating ASIC function to effect lactic acid-mediated reflex increase in arterial pressure in patients with PAD. Chronic muscle ischaemia leads to accumulation of lactic acid and other inflammatory mediators with a subsequent drop in interstitial pH. Acid-sensing ion channels (ASICs), expressed in thin muscle afferents, sense the decrease in pH and evoke a pressor reflex known to increase mean arterial pressure. The naturally occurring endomorphins are also released by primary afferents under ischaemic conditions. We examined whether high affinity mu opioid receptor (MOR) agonists, endomorphin-1 (E-1) and -2 (E-2), modulate ASIC currents and the lactic acid-mediated pressor reflex. In rat dorsal root ganglion (DRG) neurons, exposure to E-2 in acidic solutions significantly potentiated ASIC currents when compared to acidic solutions alone. The potentiation was significantly greater in DRG neurons isolated from rats whose femoral arteries were ligated for 72 h. Sustained ASIC current potentiation was also observed

  20. Human iPS Cell-Derived Germ Cells: Current Status and Clinical Potential

    Directory of Open Access Journals (Sweden)

    Tetsuya Ishii

    2014-10-01

    Full Text Available Recently, fertile spermatozoa and oocytes were generated from mouse induced pluripotent (iPS cells using a combined in vitro and in vivo induction system. With regard to germ cell induction from human iPS cells, progress has been made particularly in the male germline, demonstrating in vitro generation of haploid, round spermatids. Although iPS-derived germ cells are expected to be developed to yield a form of assisted reproductive technology (ART that can address unmet reproductive needs, genetic and/or epigenetic instabilities abound in iPS cell generation and germ cell induction. In addition, there is still room to improve the induction protocol in the female germline. However, rapid advances in stem cell research are likely to make such obstacles surmountable, potentially translating induced germ cells into the clinical setting in the immediate future. This review examines the current status of the induction of germ cells from human iPS cells and discusses the clinical potential, as well as future directions.

  1. Current and Potential Chinese Foreign Direct Investment in the Slovak Republic

    Directory of Open Access Journals (Sweden)

    Zhang Liqun

    2017-06-01

    Full Text Available This article presents an overview of current and potential investment from China into the Slovak Republic within the broader CEEC region cooperation based on the 16+1 platform. Based on a business study on the automotive industry in the CEEC region, and particularly Slovakia as one of the industrial sectors for possible Chinese investment with immense potential, the article aims to identify the main advantages and disadvantages of the region as a foreign direct investment destination. The article also analyses the impact of FDI inflows on the Slovak economy. We come to the conclusion that the recent FDI inflow from China to Slovakia has been statistically insignificant, which may, however, change in case the envisaged Chinese investment into the steel industry in Slovakia will be realised. With respect thereto, the article also points at the need to set out a new revised framework for the international legal protection of Chinese investment in the EU. It has been established that further research is required to assess the impact of Chinese FDI on the Slovak economy.

  2. The Effect of Image Potential on the Current-Voltage Characteristics of a Ferritin-layer

    Directory of Open Access Journals (Sweden)

    Eunjung Bang

    2010-11-01

    Full Text Available Considering for the concept of power storage systems, such as those used to supply power to microelectronic devices, ferritins have aroused a lot of interests for applications in bioelectrochemical devices. And electron transfer rates from the proteins to electrode surface are key determinants of overall performance and efficiency of the ferritin-based devices. Here we have investigated the electron transport mechanism of ferritin layer which was immobilized on an Au electrode. The current-voltage (I-V curves are obtained by a conductive atomic force microscope (c-AFM as a function of contact area between AFM tip and the ferritin layer. In the low voltage region, I-V curves are affected by both Fowler-Nordheim tunneling and image force. On the other hand, the experimental results are consistent with a Simmons model in a high voltage region, indicating that, as the voltage increases, the image potential has a dominant effect on the electron transport mechanism. These results are attributed to the film-like character of the ferritin layer, which generates an image potential to lower the barrier height in proportion to the voltage increment.

  3. Exploring current and potential roles of Australian community pharmacists in gout management: a qualitative study.

    Science.gov (United States)

    Counsell, Allyce B; Nguyen, Amy D; Baysari, Melissa T; Kannangara, Diluk R W; McLachlan, Andrew J; Day, Richard O

    2018-05-09

    Gout is an increasingly prevalent form of inflammatory arthritis. Although effective treatments for gout exist, current management is suboptimal due to low medication adherence rates and treatments that are non-concordant with guidelines. Medications are the mainstay and most effective form of gout management. Thus, there is potential for community pharmacists to play an important primary health care role in gout management, however their current role and their potential to improve management of gout treatment is currently unclear. The purpose of the study is to explore the views of Australian pharmacists on their roles in gout management and to identify factors influencing their involvement in gout management. A convenience sample of community pharmacists were invited to participate using a snowballing recruitment strategy. Semi-structured, face-to-face interviews were conducted with 15 pharmacists of varying age, gender and pharmacy experience. Interviews focused on pharmacists' experiences of managing gout, interactions with people living with gout and their perceived roles and responsibilities in gout management. Interviews were transcribed verbatim and independently analysed by two reviewers to identify themes. The main role of pharmacists reported in gout management was providing patient education. The greatest facilitator to pharmacists involvement in gout management was identified to be pharmacists' good understanding of gout and its management. Barriers to pharmacists involvement were identified to be difficulties in monitoring adherence to gout medications, low priority given to gout in the pharmacy compared to other chronic health conditions, and lack of specific training and/or continuing education in gout prevention and management. Pharmacists can expand their primary health care role in gout management, particularly in the area of ongoing provision of education to people living with gout and in monitoring medication adherence in patients. However, a

  4. Disease resistance breeding in rose: current status and potential of biotechnological tools.

    Science.gov (United States)

    Debener, Thomas; Byrne, David H

    2014-11-01

    The cultivated rose is a multispecies complex for which a high level of disease protection is needed due to the low tolerance of blemishes in ornamental plants. The most important fungal diseases are black spot, powdery mildew, botrytis and downy mildew. Rose rosette, a lethal viral pathogen, is emerging as a devastating disease in North America. Currently rose breeders use a recurrent phenotypic selection approach and perform selection for disease resistance for most pathogen issues in a 2-3 year field trial. Marker assisted selection could accelerate this breeding process. Thus far markers have been identified for resistance to black spot (Rdrs) and powdery mildew and with the ability of genotyping by sequencing to generate 1000s of markers our ability to identify markers useful in plant improvement should increase exponentially. Transgenic rose lines with various fungal resistance genes inserted have shown limited success and RNAi technology has potential to provide virus resistance. Roses, as do other plants, have sequences homologous to characterized R-genes in their genomes, some which have been related to specific disease resistance. With improving next generation sequencing technology, our ability to do genomic and transcriptomic studies of the resistance related genes in both the rose and the pathogens to reveal novel gene targets to develop resistant roses will accelerate. Finally, the development of designer nucleases opens up a potentially non-GMO approach to directly modify a rose's DNA to create a disease resistant rose. Although there is much potential, at present rose breeders are not using marker assisted breeding primarily because a good suite of marker/trait associations (MTA) that would ensure a path to stable disease resistance is not available. As our genomic analytical tools improve, so will our ability to identify useful genes and linked markers. Once these MTAs are available, it will be the cost savings, both in time and money, that will

  5. Student Drop-Out Trends at Sultan Qaboos University and Kuwait University: 2000-2011

    Science.gov (United States)

    Al Ghanboosi, Salim Saleem; Alqahtani, Abdulmuhsen Ayedh

    2013-01-01

    The current study aims to explore the drop-out trends at Sultan Qaboos. University and Kuwait University. Archival data of the period 2000-2011 were used to achieve this goal. Main findings showed that (a) male drop-out rates are higher than female drop-out rates; (b) drop- out rates at scientific colleges are higher; (c) drop-out rates of…

  6. Student Drop-Out from German Higher Education Institutions

    Science.gov (United States)

    Heublein, Ulrich

    2014-01-01

    28% of students of any one year currently give up their studies in bachelor degree programmes at German higher education institutions. Drop-out is to be understood as the definite termination in the higher education system without obtaining an academic degree. The drop-out rate is thereby calculated with the help of statistical estimation…

  7. Electric current arising from unpolarized polyvinyl formal

    Indian Academy of Sciences (India)

    Unknown

    An appreciable electric current is observed in a system consisting of a polyvinyl formal (PVF) film in a sandwich ... Electric current; open circuit voltage; water activated phenomenon; plasticization effect. 1. Introduction ... either the trapping parameters or the distribution of the ..... For this reason contact potential drop between.

  8. Current state, habitat and potential invasiveness of Montia linearis (Douglas ex Hook. Greene in Poland

    Directory of Open Access Journals (Sweden)

    Iwona Dembicz

    2015-10-01

    Full Text Available Montia linearis is a vascular plant originating from western North America. The expansion of this species has been observed for several decades. For the first time M. linearis was found in Europe in 1989. Further six populations were documented by 2004 within the continent: three in Poland, two in Denmark and one in Hungary. Apart from discovering a new population of M. linearis, we confirmed two out of the three previously known localities of the species in Poland. All the currently known populations of M. linearis occupied predominantly meadow habitats, especially intensively managed sites. Some individuals were also found in disturbed sites with bare soil. The studied species inhabited soils of various types with broad range of fertility as well as humidity. Montia linearis populations reached densities up to 87 individuals per 0.04 m2. The number of seeds produced by an individual was between 10 and 55 in 90% of the studied specimens, however much more fertile specimens were also observed. As the previously presented hypothesis of M. linearis dispersal with rail transport seemed not to be well supported, the connection between the M. linearis presence and cattle husbandry is considered. It is possible that the species can be transferred with living animals or manure. The species was able to survive for at least 26 years within once inhabited site. Further spread of M. linearis within Europe is highly probable. The aim of the study is to: (i describe the current state of populations of M. linearis in Poland, (ii provide information on habitat preferences and biology of the species, (iii assess the invasiveness potential of M. linearis in Poland.

  9. Improvement Strategies, Cost Effective Production, and Potential Applications of Fungal Glucose Oxidase (GOD: Current Updates

    Directory of Open Access Journals (Sweden)

    Manish K. Dubey

    2017-06-01

    Full Text Available Fungal glucose oxidase (GOD is widely employed in the different sectors of food industries for use in baking products, dry egg powder, beverages, and gluconic acid production. GOD also has several other novel applications in chemical, pharmaceutical, textile, and other biotechnological industries. The electrochemical suitability of GOD catalyzed reactions has enabled its successful use in bioelectronic devices, particularly biofuel cells, and biosensors. Other crucial aspects of GOD such as improved feeding efficiency in response to GOD supplemental diet, roles in antimicrobial activities, and enhancing pathogen defense response, thereby providing induced resistance in plants have also been reported. Moreover, the medical science, another emerging branch where GOD was recently reported to induce several apoptosis characteristics as well as cellular senescence by downregulating Klotho gene expression. These widespread applications of GOD have led to increased demand for more extensive research to improve its production, characterization, and enhanced stability to enable long term usages. Currently, GOD is mainly produced and purified from Aspergillus niger and Penicillium species, but the yield is relatively low and the purification process is troublesome. It is practical to build an excellent GOD-producing strain. Therefore, the present review describes innovative methods of enhancing fungal GOD production by using genetic and non-genetic approaches in-depth along with purification techniques. The review also highlights current research progress in the cost effective production of GOD, including key advances, potential applications and limitations. Therefore, there is an extensive need to commercialize these processes by developing and optimizing novel strategies for cost effective GOD production.

  10. THE POTENTIAL FOR NEUTRINO PHYSICS AT MUON COLLIDERS AND DEDICATED HIGH CURRENT MUON STORAGE RINGS

    International Nuclear Information System (INIS)

    BIGI, I.; BOLTON, T.; FORMAGGIO, J.; HARRIS, D.; MORFIN, J.; SPENTZOURIS, P.; YU, J.; KAYSER, B.; KING, B.J.; MCFARLAND, K.; PETROV, A.; SCHELLMAN, H.; VELASCO, M.; SHROCK, R.

    2000-01-01

    Conceptual design studies are underway for both muon colliders and high-current non-colliding muon storage rings that have the potential to become the first true neutrino factories. Muon decays in long straight sections of the storage rings would produce uniquely intense and precisely characterized two-component neutrino beams--muon neutrinos plus electron antineutrinos from negative muon decays and electron neutrinos plus muon antineutrinos from positive muons. This article presents a long-term overview of the prospects for these facilities to greatly extend the capabilities for accelerator-based neutrino physics studies for both high rate and long baseline neutrino experiments. As the first major physics topic, recent experimental results involving neutrino oscillations have motivated a vigorous design effort towards dedicated neutrino factories that would store muon beams of energies 50 GeV or below. These facilities hold the promise of neutrino oscillation experiments with baselines up to intercontinental distances and utilizing well understood beams that contain, for the first time, a substantial component of multi-GeV electron-flavored neutrinos. In deference to the active and fast-moving nature of neutrino oscillation studies, the discussion of long baseline physics at neutrino factories has been limited to a concise general overview of the relevant theory, detector technologies, beam properties, experimental goals and potential physics capabilities. The remainder of the article is devoted to the complementary high rate neutrino experiments that would study neutrino-nucleon and neutrino-electron scattering and would be performed at high performance detectors placed as close as is practical to the neutrino production straight section of muon storage rings in order to exploit beams with transverse dimensions as small as a few tens of centimeters

  11. THE POTENTIAL FOR NEUTRINO PHYSICS AT MUON COLLIDERS AND DEDICATED HIGH CURRENT MUON STORAGE RINGS

    Energy Technology Data Exchange (ETDEWEB)

    BIGI,I.; BOLTON,T.; FORMAGGIO,J.; HARRIS,D.; MORFIN,J.; SPENTZOURIS,P.; YU,J.; KAYSER,B.; KING,B.J.; MCFARLAND,K.; PETROV,A.; SCHELLMAN,H.; VELASCO,M.; SHROCK,R.

    2000-05-11

    Conceptual design studies are underway for both muon colliders and high-current non-colliding muon storage rings that have the potential to become the first true neutrino factories. Muon decays in long straight sections of the storage rings would produce uniquely intense and precisely characterized two-component neutrino beams--muon neutrinos plus electron antineutrinos from negative muon decays and electron neutrinos plus muon antineutrinos from positive muons. This article presents a long-term overview of the prospects for these facilities to greatly extend the capabilities for accelerator-based neutrino physics studies for both high rate and long baseline neutrino experiments. As the first major physics topic, recent experimental results involving neutrino oscillations have motivated a vigorous design effort towards dedicated neutrino factories that would store muon beams of energies 50 GeV or below. These facilities hold the promise of neutrino oscillation experiments with baselines up to intercontinental distances and utilizing well understood beams that contain, for the first time, a substantial component of multi-GeV electron-flavored neutrinos. In deference to the active and fast-moving nature of neutrino oscillation studies, the discussion of long baseline physics at neutrino factories has been limited to a concise general overview of the relevant theory, detector technologies, beam properties, experimental goals and potential physics capabilities. The remainder of the article is devoted to the complementary high rate neutrino experiments that would study neutrino-nucleon and neutrino-electron scattering and would be performed at high performance detectors placed as close as is practical to the neutrino production straight section of muon storage rings in order to exploit beams with transverse dimensions as small as a few tens of centimeters.

  12. Hanging drop crystal growth apparatus

    Science.gov (United States)

    Naumann, Robert J. (Inventor); Witherow, William K. (Inventor); Carter, Daniel C. (Inventor); Bugg, Charles E. (Inventor); Suddath, Fred L. (Inventor)

    1990-01-01

    This invention relates generally to control systems for controlling crystal growth, and more particularly to such a system which uses a beam of light refracted by the fluid in which crystals are growing to detect concentration of solutes in the liquid. In a hanging drop apparatus, a laser beam is directed onto drop which refracts the laser light into primary and secondary bows, respectively, which in turn fall upon linear diode detector arrays. As concentration of solutes in drop increases due to solvent removal, these bows move farther apart on the arrays, with the relative separation being detected by arrays and used by a computer to adjust solvent vapor transport from the drop. A forward scattering detector is used to detect crystal nucleation in drop, and a humidity detector is used, in one embodiment, to detect relative humidity in the enclosure wherein drop is suspended. The novelty of this invention lies in utilizing angular variance of light refracted from drop to infer, by a computer algorithm, concentration of solutes therein. Additional novelty is believed to lie in using a forward scattering detector to detect nucleating crystallites in drop.

  13. Orexin-A potentiates L-type calcium/barium currents in rat retinal ganglion cells.

    Science.gov (United States)

    Liu, F; Weng, S-J; Yang, X-L; Zhong, Y-M

    2015-10-01

    Two neuropeptides, orexin-A and orexin-B (also called hypocretin-1 and -2), have been implicated in sleep/wake regulation, feeding behaviors via the activation of two subtypes of G-protein-coupled receptors: orexin 1 and orexin 2 receptors (OX1R and OX2R). While the expression of orexins and orexin receptors is immunohistochemically revealed in retinal neurons, the function of these peptides in the retina is largely unknown. Using whole-cell patch-clamp recordings in rat retinal slices, we demonstrated that orexin-A increased L-type-like barium currents (IBa,L) in ganglion cells (GCs), and the effect was blocked by the selective OX1R antagonist SB334867, but not by the OX2R antagonist TCS OX2 29. The orexin-A effect was abolished by intracellular dialysis of GDP-β-S/GPAnt-2A, a Gq protein inhibitor, suggesting the mediation of Gq. Additionally, during internal dialysis of the phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor U73122, orexin-A did not change the IBa,L of GCs, whereas the orexin-A effect persisted in the presence of the phosphatidylcholine (PC)-PLC inhibitor D609. The orexin-A-induced potentiation was not seen with internal infusion of Ca(2+)-free solution or when inositol 1,4,5-trisphosphate (IP3)-sensitive Ca(2+) release from intracellular stores was blocked by heparin/xestospongins-C. Moreover, the orexin-A effect was mimicked by the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate, but was eliminated when PKC was inhibited by bisindolylmaleimide IV (Bis-IV)/Gö6976. Neither adenosine 3',5'-cyclic monophosphate (cAMP)-protein kinase A (PKA) nor guanosine 3',5'-cyclic monophosphate (cGMP)-protein kinase G (PKG) signaling pathway was likely involved, as orexin-A persisted to potentiate the IBa,L of GCs no matter these two pathways were activated or inhibited. These results suggest that, by activating OX1R, orexin-A potentiates the IBa,L of rat GCs through a distinct Gq/PI-PLC/IP3/Ca(2+)/PKC signaling pathway. Copyright

  14. US refining capacity for Canadian heavy oil : current overview and future potential

    International Nuclear Information System (INIS)

    Paget, S.

    2006-01-01

    This presentation provided an overview of the Canadian oil sands industry and investigated the potential heavy oil refining capacity of the United States. An outline of the first commercial developments of steam assisted gravity drainage (SAGD) in Alberta's oil sands was provided. Canada's reserves were compared with oil shale and heavy oil reserves in the United States and Venezuela. Influences of Canadian developments from western Canadian conventional crude oil were reviewed, and an oil sands production forecast was provided. Recent refining developments in the United States include delayed coking; catalytic cracking; fluid coking; flexicoking; and LC-fining. However, many oil sand producers are now choosing to upgrade oil, and producers are currently saturating United States markets with heavy crude oil. Canadian crude prices reached $90 per barrel in 2006. Heavy oil pipelines are now being constructed and existing heavy oil pipelines are being expanded. ConocoPhillips is planning to invest $1 billion for a new heavy oil coker, while BP is investing $3 billion for a heavy oil refinery in Indiana which plans to refine Canadian crude oil supplies. However, bitumens from Alberta are volatile in price, and excess Canadian production must be exported. Less than 10 per cent of western Canadian crude has tidewater access, and capital providers are concerned about cost over-runs. In order for the Canadian oil sands industry to succeed, refining capacity in the United States must be expanded, and open access must be provided to the Gulf coast as well as to the Pacific Ocean. tabs., figs

  15. Current research and potential applications of the Concealed Information Test: An overview

    Directory of Open Access Journals (Sweden)

    Gershon eBen-Shakhar

    2012-09-01

    Full Text Available Research interest in psychophysiological detection of deception has significantly increased since the September 11 terror attack in the USA. In particular, the Concealed Information Test (CIT, designed to detect memory traces that can connect suspects to a certain crime, has been extensively studied. In this paper I will briefly review several psychophysiological detection paradigms that have been studied, with a focus on the CIT. The theoretical background of the CIT, its strength and weaknesses, its potential applications as well as research finings related to its validity, (based on a recent mata-analytic study, will be discussed. Several novel research directions, with a focus on factors that may affect CIT detection in realistic settings (e.g., memory for crime details; the effect of emotional stress during crime execution will be described. Additionally, research focusing on mal-intentions and attempts to detect terror networks using information gathered from groups of suspects using both the standard CIT and the searching CIT will be reviewed. Finally, implications of current research to the actual application of the CIT will be discussed and several recommendations that can enhance the use of the CIT will be made.

  16. Current Government Actions and Potential Policy Options for Reducing Obesity in Queensland Schools

    Directory of Open Access Journals (Sweden)

    Naser A. Alsharairi

    2018-01-01

    Full Text Available School nutrition policies provide promising avenues towards the improvement of children’s eating habits and the prevention of obesity. Childhood obesity rates and related chronic diseases are increasing in Queensland, in part as a result of unhealthy eating habits and lack of physical activity. There is a very high investment by the Queensland government in maintaining healthy weight and promoting nutrition and physical activity among schoolchildren through delivering a range of initiatives across the state. However, there is a lack of evidence concerning the effectiveness of nutrition/physical education and parental involvement programs addressing obesity delivered in Queensland schools. This paper can be used to guide government and policy-makers regarding the most effective policy options that will promote healthy eating and physical activity among Queensland schoolchildren. The aim of this paper is to: (i summarize current evidence on Queensland government responses to obesity; and (ii discuss potential policy options that could support healthy eating and regular physical activity, and examine the evidence base for each option and suggest new areas for future research.

  17. Computer-aided diagnosis for screening of breast cancer on mammograms. Current status and future potential

    International Nuclear Information System (INIS)

    Doi, Kunio

    2007-01-01

    Described are the history, current status and future potential of computer-aided diagnosis (CAD) with particular emphasis on screening mammography for breast cancer. The systematic basic and clinical studies on CAD started around 20 years before and the significance of CAD has been well recognized to be evident because of human errors occurring in the visual check by doctors of so numerous screening images. Improvement of diagnostic accuracy by CAD has been demonstrated by statistical analysis of ROC (receiver operating characteristic) curves. In mammography, reviewed is detection of the early stage breast cancer like microcalcifications by computer alone, by CAD plus one or more doctors' reading, and by practical clinical CAD diagnosis. For differential diagnosis for malignancy, microcalcifications and masses are given their characteristic image properties and the results are that the Az-value (area under ROC curve) is higher in CAD than in doctor's (0.80 vs 0.61) in the former and, doctor's (0.93) is improved by CAD to 0.96 in the latter masses. In this diagnosis, similar images in the digital database are useful and the database can learn by repeated input of individual data by neural network. Detection of the lesion and especially, its differential diagnosis will be more important in parallel to database development and CAD will be also useful for doctor' carrier as an educational mean. (R.T.)

  18. Bariatric surgery and nonalcoholic fatty liver disease: current and potential future treatments

    Directory of Open Access Journals (Sweden)

    Akira eSasaki

    2014-10-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD and nonalcoholic steatohepatitis (NASH are increasingly common cause of chronic liver disease worldwide. The diagnosis of NASH is challenging as most affected patients are symptom-free and the role of routine screening is not clearly established. Most patients with severe obesity who undergo bariatric surgery have NAFLD, which is associated insulin resistance, type 2 diabetes mellitus (T2DM, hypertension, and obesity-related dyslipidemia. The effective treatment for NAFLD is weight reduction through lifestyle modifications, antiobesity medication, or bariatric surgery. Among these treatments, bariatric surgery is the most reliable method for achieving substantial, sustained weight loss. This procedure is safe when performed by a skilled surgeon, and the benefits include reduced weight, improved quality of life, decreased obesity-related comorbidities, and increased life expectancy. Further research is urgently needed to determine the best use of bariatric surgery with NAFLD patients at high risk of developing liver cirrhosis and its role in modulating complications of NAFLD, such as T2DM and cardiovascular disease. The current evidence suggests that bariatric surgery for patients with severe obesity decreases the grade of steatosis, hepatic inflammation, and fibrosis. However, further long-term studies are required to confirm the true effects before recommending bariatric surgery as a potential treatment for nonalcoholic steatohepatitis.

  19. An eddy current vector potential formulation for estimating hysteresis losses of superconductors with FEM

    International Nuclear Information System (INIS)

    Stenvall, A; Tarhasaari, T

    2010-01-01

    Many people these days employ only commercial finite element method (FEM) software when solving for the hysteresis losses of superconductors. Thus, the knowledge of a modeller is in the capability of using the black boxes of software efficiently. This has led to a relatively superficial examination of different formulations while the discussion stays mainly on the usage of the user interfaces of these programs. Also, if we stay only at the mercy of commercial software producers, we end up having less and less knowledge on the details of solvers. Then, it becomes more and more difficult to conceptually solve new kinds of problem. This may prevent us finding new kinds of method to solve old problems more efficiently, or finding a solution for a problem that was considered almost impossible earlier. In our earlier research, we presented the background of a co-tree gauged T-ψ FEM solver for computing the hysteresis losses of superconductors. In this paper, we examine the feasibility of FEM and eddy current vector potential formulation in the same problem.

  20. Meniscus repair and regeneration: review on current methods and research potential

    Directory of Open Access Journals (Sweden)

    C Scotti

    2013-01-01

    Full Text Available Meniscus regeneration is an unsolved clinical challenge. Despite the wide acceptance of the degenerative consequences of meniscectomy, no surgical procedure has succeeded to date in regenerating a functional and long-lasting meniscal fibrocartilage. Research proposed a number of experimental approaches encompassing all the typical strategies of regenerative medicine: cell-free scaffolds, gene therapy, intra-articular delivery of progenitor cells, biological glues for enhanced bonding of reparable tears, partial and total tissue engineered meniscus replacement. None of these approaches has been completely successful and can be considered suitable for all patients, as meniscal tears require specific and patient-related treatments depending on the size and type of lesion. Recent advances in cell biology, biomaterial science and bioengineering (e.g., bioreactors have now the potential to drive meniscus regeneration into a series of clinically relevant strategies. In this tutorial paper, the clinical need for meniscus regeneration strategies will be explained, and past and current experimental studies on meniscus regeneration will be reported.

  1. Substance use by Egyptian youth: current patterns and potential avenues for prevention.

    Science.gov (United States)

    Loffredo, Christopher A; Boulos, Dina N K; Saleh, Doa'a A; Jillson, Irene A; Garas, Magdy; Loza, Nasser; Samuel, Philip; Shaker, Yousri Edward; Ostrowski, Mar-Jan; Amr, Sania

    2015-04-01

    Substance abuse in Egypt is a serious public health threat. Recent studies have demonstrated increases in the prevalence of the use of tobacco, illegal drugs, and over-the-counter drugs, particularly among youth. We conducted focus groups with a total of 40 male and female youth participants, ages 12-14 and 15-18, recruited from two different areas (Cairo and Alexandria) in 2012. We investigated their knowledge and perceptions regarding current substance use, its sources, and promoting and protecting factors, broadly addressing the use of tobacco products, illicit and prescription drugs, inhaled substances such as glue and solvents, and alcohol. Our findings suggest that: (1) youth in Egypt had access to and were actively using substances encountered in similar research worldwide, including tobacco, alcohol, illicit drugs, glue sniffing, and pharmaceutical agents; (2) smoking cigarettes and using hashish were the most common practices, and Tramadol was the most commonly used pharmaceutical drug; (3) peer pressure from friends stood out as the most common reason to start and continue using substances, followed by adverse life events and having a parent or family member who used substances; (4) strict parenting, religiosity, and having non-user friends were among the factors perceived by youth to prevent substance use or help them quit using substances; (5) most youths were aware of the adverse health effects of substance use. These findings will inform the design of quantitative surveys aimed at estimating the prevalence of specific behaviors related to substance use among youth and potential avenues for prevention.

  2. Current and potential uses of bioactive molecules from marine processing waste.

    Science.gov (United States)

    Suleria, Hafiz Ansar Rasul; Masci, Paul; Gobe, Glenda; Osborne, Simone

    2016-03-15

    Food industries produce huge amounts of processing waste that are often disposed of incurring expenses and impacting upon the environment. For these and other reasons, food processing waste streams, in particular marine processing waste streams, are gaining popularity amongst pharmaceutical, cosmetic and nutraceutical industries as sources of bioactive molecules. In the last 30 years, there has been a gradual increase in processed marine products with a concomitant increase in waste streams that include viscera, heads, skins, fins, bones, trimmings and shellfish waste. In 2010, these waste streams equated to approximately 24 million tonnes of mostly unused resources. Marine processing waste streams not only represent an abundant resource, they are also enriched with structurally diverse molecules that possess a broad panel of bioactivities including anti-oxidant, anti-coagulant, anti-thrombotic, anti-cancer and immune-stimulatory activities. Retrieval and characterisation of bioactive molecules from marine processing waste also contributes valuable information to the vast field of marine natural product discovery. This review summarises the current use of bioactive molecules from marine processing waste in different products and industries. Moreover, this review summarises new research into processing waste streams and the potential for adoption by industries in the creation of new products containing marine processing waste bioactives. © 2015 Society of Chemical Industry.

  3. Artificial intelligence in diagnosis of obstructive lung disease: current status and future potential.

    Science.gov (United States)

    Das, Nilakash; Topalovic, Marko; Janssens, Wim

    2018-03-01

    The application of artificial intelligence in the diagnosis of obstructive lung diseases is an exciting phenomenon. Artificial intelligence algorithms work by finding patterns in data obtained from diagnostic tests, which can be used to predict clinical outcomes or to detect obstructive phenotypes. The purpose of this review is to describe the latest trends and to discuss the future potential of artificial intelligence in the diagnosis of obstructive lung diseases. Machine learning has been successfully used in automated interpretation of pulmonary function tests for differential diagnosis of obstructive lung diseases. Deep learning models such as convolutional neural network are state-of-the art for obstructive pattern recognition in computed tomography. Machine learning has also been applied in other diagnostic approaches such as forced oscillation test, breath analysis, lung sound analysis and telemedicine with promising results in small-scale studies. Overall, the application of artificial intelligence has produced encouraging results in the diagnosis of obstructive lung diseases. However, large-scale studies are still required to validate current findings and to boost its adoption by the medical community.

  4. Current situation, potentials and prospects for the development of organic farming in Šumadija

    Directory of Open Access Journals (Sweden)

    Brković Duško

    2016-01-01

    Full Text Available Šumadija is rich in natural potentials which provide a good basis for the future development of organic farming, given the fact that natural resources are limited. The composition and structure of natural resources are highly suitable for organic production. The region's relatively unpolluted land, favourable climate, abundant water resources and preserved biodiversity are some of the main organic farming requirements satisfied. Organic production is not possible without ensuring at least a minimum level of preservation of natural resources in areas where organic farming is practised; on the other hand, organic production itself has a positive effect on the preservation and improvement of environmental quality in these areas. Small plots of land can be advantageous for this production, particularly in upland areas, and used specifically for organic production as the conversion period is short. They can be used for vegetable farming because the soil is uncontaminated owing to distance from roads. Positive experience indicates that potatoes, rye, oats and root vegetables can be successfully grown in these areas. Another advantage is the wealth of indigenous cultivars of apples, pears and plums which are highly resistant to pathogenic pests and environmental conditions, and hence suitable for cultivation without the use of mineral fertilisers and chemical agents. Major issues currently facing organic farming are a small-scale organic market and low prices of organic products, a low level of consumer awareness of the advantages of organic farming, suspicion and ignorance, low purchasing power, low availability of organic products through sales channels, etc.

  5. African medicinal plants and their derivatives: Current efforts towards potential anti-cancer drugs.

    Science.gov (United States)

    Mbele, Mzwandile; Hull, Rodney; Dlamini, Zodwa

    2017-10-01

    Cancer is a leading cause of mortality and morbidity worldwide and second only to cardiovascular diseases. Cancer is a challenge in African countries because generally there is limited funding available to deal with the cancer epidemic and awareness and this should be prioritised and all possible resources should be utilized to prevent and treat cancer. The current review reports on the role of African medicinal plants in the treatment of cancer, and also outlines methodologies that can also be used to achieve better outcomes for cancer treatment. This review outlines African medicinal plants, isolated compounds and technologies that can be used to advance cancer research. Chemical structures of isolated compounds have an important role in anti-cancer treatments; new technologies and methods may assist to identify more properties of African medicinal plants and the treatment of cancer. In conclusion, African medicinal plants have shown their potential as enormous resources for novel cytotoxicity compounds. Finally it has been noted that the cytotoxicity depends on the chemical structural arrangements of African medicinal plants compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Applications of Ni3Al Based Intermetallic Alloys—Current Stage and Potential Perceptivities

    Directory of Open Access Journals (Sweden)

    Pawel Jozwik

    2015-05-01

    Full Text Available The paper presents an overview of current and prospective applications of Ni3Al based intermetallic alloys—modern engineering materials with special properties that are potentially useful for both structural and functional purposes. The bulk components manufactured from these materials are intended mainly for forging dies, furnace assembly, turbocharger components, valves, and piston head of internal combustion engines. The Ni3Al based alloys produced by a directional solidification are also considered as a material for the fabrication of jet engine turbine blades. Moreover, development of composite materials with Ni3Al based alloys as a matrix hardened by, e.g., TiC, ZrO2, WC, SiC and graphene, is also reported. Due to special physical and chemical properties; it is expected that these materials in the form of thin foils and strips should make a significant contribution to the production of high tech devices, e.g., Micro Electro-Mechanical Systems (MEMS or Microtechnology-based Energy and Chemical Systems (MECS; as well as heat exchangers; microreactors; micro-actuators; components of combustion chambers and gasket of rocket and jet engines as well components of high specific strength systems. Additionally, their catalytic properties may find an application in catalytic converters, air purification systems from chemical and biological toxic agents or in a hydrogen “production” by a decomposition of hydrocarbons.

  7. Current Status and Future Potential of Energy Derived from Chinese Agricultural Land: A Review

    Directory of Open Access Journals (Sweden)

    Ningning Zhai

    2015-01-01

    Full Text Available Energy crisis is receiving attention with regard to the global economy and environmental sustainable development. Developing new energy resources to optimize the energy supply structure has become an important measure to prevent energy shortage as well as achieving energy conservation and emission reduction in China. This study proposed the concept of energy agriculture and constructed an energy agricultural technical support system based on the analysis of energy supply and demand and China’s foreign dependence on energy resources, combined with the function of agriculture in the energy field. Manufacturing technology equipment and agricultural and forestry energy, including crop or forestry plants and animal feces, were used in the system. The current status and future potential of China’s marginal land resources, energy crop germplasm resources, and agricultural and forestry waste energy-oriented resources were analyzed. Developing the function of traditional agriculture in food production may promote China’s social, economic, and environmental sustainable development and achieve energy saving and emission reduction.

  8. Ground Motion Prediction Equations Empowered by Stress Drop Measurement

    Science.gov (United States)

    Miyake, H.; Oth, A.

    2015-12-01

    Significant variation of stress drop is a crucial issue for ground motion prediction equations and probabilistic seismic hazard assessment, since only a few ground motion prediction equations take into account stress drop. In addition to average and sigma studies of stress drop and ground motion prediction equations (e.g., Cotton et al., 2013; Baltay and Hanks, 2014), we explore 1-to-1 relationship for each earthquake between stress drop and between-event residual of a ground motion prediction equation. We used the stress drop dataset of Oth (2013) for Japanese crustal earthquakes ranging 0.1 to 100 MPa and K-NET/KiK-net ground motion dataset against for several ground motion prediction equations with volcanic front treatment. Between-event residuals for ground accelerations and velocities are generally coincident with stress drop, as investigated by seismic intensity measures of Oth et al. (2015). Moreover, we found faster attenuation of ground acceleration and velocities for large stress drop events for the similar fault distance range and focal depth. It may suggest an alternative parameterization of stress drop to control attenuation distance rate for ground motion prediction equations. We also investigate 1-to-1 relationship and sigma for regional/national-scale stress drop variation and current national-scale ground motion equations.

  9. Computer-aided diagnosis in medical imaging: historical review, current status and future potential.

    Science.gov (United States)

    Doi, Kunio

    2007-01-01

    Computer-aided diagnosis (CAD) has become one of the major research subjects in medical imaging and diagnostic radiology. In this article, the motivation and philosophy for early development of CAD schemes are presented together with the current status and future potential of CAD in a PACS environment. With CAD, radiologists use the computer output as a "second opinion" and make the final decisions. CAD is a concept established by taking into account equally the roles of physicians and computers, whereas automated computer diagnosis is a concept based on computer algorithms only. With CAD, the performance by computers does not have to be comparable to or better than that by physicians, but needs to be complementary to that by physicians. In fact, a large number of CAD systems have been employed for assisting physicians in the early detection of breast cancers on mammograms. A CAD scheme that makes use of lateral chest images has the potential to improve the overall performance in the detection of lung nodules when combined with another CAD scheme for PA chest images. Because vertebral fractures can be detected reliably by computer on lateral chest radiographs, radiologists' accuracy in the detection of vertebral fractures would be improved by the use of CAD, and thus early diagnosis of osteoporosis would become possible. In MRA, a CAD system has been developed for assisting radiologists in the detection of intracranial aneurysms. On successive bone scan images, a CAD scheme for detection of interval changes has been developed by use of temporal subtraction images. In the future, many CAD schemes could be assembled as packages and implemented as a part of PACS. For example, the package for chest CAD may include the computerized detection of lung nodules, interstitial opacities, cardiomegaly, vertebral fractures, and interval changes in chest radiographs as well as the computerized classification of benign and malignant nodules and the differential diagnosis of

  10. Sludge pipe flow pressure drop prediction using composite power ...

    African Journals Online (AJOL)

    Sludge pipe flow pressure drop prediction using composite power-law friction ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue ... When predicting pressure gradients for the flow of sludges in pipes, the ...

  11. Obtaining subjects' consent to publish identifying personal information: current practices and identifying potential issues.

    Science.gov (United States)

    Yoshida, Akiko; Dowa, Yuri; Murakami, Hiromi; Kosugi, Shinji

    2013-11-25

    In studies publishing identifying personal information, obtaining consent is regarded as necessary, as it is impossible to ensure complete anonymity. However, current journal practices around specific points to consider when obtaining consent, the contents of consent forms and how consent forms are managed have not yet been fully examined. This study was conducted to identify potential issues surrounding consent to publish identifying personal information. Content analysis was carried out on instructions for authors and consent forms developed by academic journals in four fields (as classified by Journal Citation Reports): medicine general and internal, genetics and heredity, pediatrics, and psychiatry. An online questionnaire survey of editors working for journals that require the submission of consent forms was also conducted. Instructions for authors were reviewed for 491 academic journals (132 for medicine general and internal, 147 for genetics and heredity, 100 for pediatrics, and 112 for psychiatry). Approximately 40% (203: 74 for medicine general and internal, 31 for genetics and heredity, 58 for pediatrics, and 40 for psychiatry) stated that subject consent was necessary. The submission of consent forms was required by 30% (154) of the journals studied, and 10% (50) provided their own consent forms for authors to use. Two journals mentioned that the possible effects of publication on subjects should be considered. Many journal consent forms mentioned the difficulties in ensuring complete anonymity of subjects, but few addressed the study objective, the subjects' right to refuse consent and the withdrawal of consent. The main reason for requiring the submission of consent forms was to confirm that consent had been obtained. Approximately 40% of journals required subject consent to be obtained. However, differences were observed depending on the fields. Specific considerations were not always documented. There is a need to address issues around the study

  12. Obtaining subjects’ consent to publish identifying personal information: current practices and identifying potential issues

    Science.gov (United States)

    2013-01-01

    Background In studies publishing identifying personal information, obtaining consent is regarded as necessary, as it is impossible to ensure complete anonymity. However, current journal practices around specific points to consider when obtaining consent, the contents of consent forms and how consent forms are managed have not yet been fully examined. This study was conducted to identify potential issues surrounding consent to publish identifying personal information. Methods Content analysis was carried out on instructions for authors and consent forms developed by academic journals in four fields (as classified by Journal Citation Reports): medicine general and internal, genetics and heredity, pediatrics, and psychiatry. An online questionnaire survey of editors working for journals that require the submission of consent forms was also conducted. Results Instructions for authors were reviewed for 491 academic journals (132 for medicine general and internal, 147 for genetics and heredity, 100 for pediatrics, and 112 for psychiatry). Approximately 40% (203: 74 for medicine general and internal, 31 for genetics and heredity, 58 for pediatrics, and 40 for psychiatry) stated that subject consent was necessary. The submission of consent forms was required by 30% (154) of the journals studied, and 10% (50) provided their own consent forms for authors to use. Two journals mentioned that the possible effects of publication on subjects should be considered. Many journal consent forms mentioned the difficulties in ensuring complete anonymity of subjects, but few addressed the study objective, the subjects’ right to refuse consent and the withdrawal of consent. The main reason for requiring the submission of consent forms was to confirm that consent had been obtained. Conclusion Approximately 40% of journals required subject consent to be obtained. However, differences were observed depending on the fields. Specific considerations were not always documented. There is a need

  13. Evaluating Cloud and Precipitation Processes in Numerical Models using Current and Potential Future Satellite Missions

    Science.gov (United States)

    van den Heever, S. C.; Tao, W. K.; Skofronick Jackson, G.; Tanelli, S.; L'Ecuyer, T. S.; Petersen, W. A.; Kummerow, C. D.

    2015-12-01

    Cloud, aerosol and precipitation processes play a fundamental role in the water and energy cycle. It is critical to accurately represent these microphysical processes in numerical models if we are to better predict cloud and precipitation properties on weather through climate timescales. Much has been learned about cloud properties and precipitation characteristics from NASA satellite missions such as TRMM, CloudSat, and more recently GPM. Furthermore, data from these missions have been successfully utilized in evaluating the microphysical schemes in cloud-resolving models (CRMs) and global models. However, there are still many uncertainties associated with these microphysics schemes. These uncertainties can be attributed, at least in part, to the fact that microphysical processes cannot be directly observed or measured, but instead have to be inferred from those cloud properties that can be measured. Evaluation of microphysical parameterizations are becoming increasingly important as enhanced computational capabilities are facilitating the use of more sophisticated schemes in CRMs, and as future global models are being run on what has traditionally been regarded as cloud-resolving scales using CRM microphysical schemes. In this talk we will demonstrate how TRMM, CloudSat and GPM data have been used to evaluate different aspects of current CRM microphysical schemes, providing examples of where these approaches have been successful. We will also highlight CRM microphysical processes that have not been well evaluated and suggest approaches for addressing such issues. Finally, we will introduce a potential NASA satellite mission, the Cloud and Precipitation Processes Mission (CAPPM), which would facilitate the development and evaluation of different microphysical-dynamical feedbacks in numerical models.

  14. Studying the field induced breakup of acoustically levitated drops

    Science.gov (United States)

    Warschat, C.; Riedel, J.

    2017-10-01

    Coulomb fission of charged droplets (The terms drop and droplet are often used synonymous. Throughout this manuscript, to avoid confusion, the terms drop and droplet will be used for liquid spheres with radii in the millimeter range and the micrometer range, respectively. In our experiments, the first correspond to the parent drop while the latter describes the ejected progeny droplets.) is a well-studied natural phenomenon. Controlled droplet fission is already successfully employed in several technological applications. Still, since the occurring surface rupture relies on the exact understanding and description of the liquid gas boundary, some details are still under debate. Most empirical systematic studies observe falling micrometer droplets passing through the electric field inside a plate capacitor. This approach, although easily applicable and reliable, limits the experimental degrees of freedom regarding the observable time and the maximum size of the drops and can only be performed in consecutive individual observations of different subsequent drops. Here we present a novel setup to study the field induced breakup of acoustically levitated drops. The design does not bear any restrictions towards the temporal window of observation, and allows handling of drops of a tunable radius ranging from 10 μm to several millimeters and a real-time monitoring of one single drop. Our comprehensive study includes a time resolved visual inspection, laser shadowgraphy, laser induced fluorescence imaging, and ambient mass spectrometric interrogation of the nascent Taylor cone. The results shown for a millimeter sized drop, previously inaccessible for Coulomb fission experiments, are mostly comparable with previous results for smaller drops. The major difference is the time scale and the threshold potential of the drop rupture. Both values, however, resemble theoretically extrapolations to the larger radius. The technique allows for a systematic study of breakup behavior of

  15. Semisupervised Community Detection by Voltage Drops

    Directory of Open Access Journals (Sweden)

    Min Ji

    2016-01-01

    Full Text Available Many applications show that semisupervised community detection is one of the important topics and has attracted considerable attention in the study of complex network. In this paper, based on notion of voltage drops and discrete potential theory, a simple and fast semisupervised community detection algorithm is proposed. The label propagation through discrete potential transmission is accomplished by using voltage drops. The complexity of the proposal is OV+E for the sparse network with V vertices and E edges. The obtained voltage value of a vertex can be reflected clearly in the relationship between the vertex and community. The experimental results on four real networks and three benchmarks indicate that the proposed algorithm is effective and flexible. Furthermore, this algorithm is easily applied to graph-based machine learning methods.

  16. Potentiation of intraocular absorption and drug metabolism of N-acetylcarnosine lubricant eye drops: drug interaction with sight threatening lipid peroxides in the treatment for age-related eye diseases.

    Science.gov (United States)

    Babizhayev, Mark A

    2009-01-01

    Cataract is the dominant cause of blindness worldwide. Studies of the morphological structure and biophysical changes of the lens in human senile cataracts have demonstrated the disappearance of normal fiber structure in the opaque region of the lens and the disintegration of the lens fiber plasma membrane in the lens tissue. Morphological and biochemical techniques have revealed the regions in human cataractous lenses in which the plasma membrane derangement occurs as the primary light scattering centers which cause the observed lens opacity. Human cataract formation is mostly considered to be a multifactorial disease; however, oxidative stress might be one of the leading causes for both nuclear and cortical cataract. Phospholipid molecules modified with oxygen, accumulating in the lipid bilayer, change its geometry and impair lipid-lipid and protein-lipid interactions in lenticular fiber membranes. Electron microscopy data of human lenses at various stages of age-related cataract document that these disruptions were globules, vacuoles, multilamellar membranes, and clusters of highly undulating membranes. The opaque shades of cortical cataracts represent cohorts of locally affected fibres segregated from unaffected neighbouring fibres by plasma membranes. Other potential scattering centers found throughout the mature cataract nucleus included variations in staining density between adjacent cells, enlarged extracellular spaces between undulating membrane pairs, and protein-like deposits in the extracellular space. These affected parts had membranes with a fine globular aspect and in cross-section proved to be filled with medium to large globular elements. Lipid peroxidation (LPO) is a pathogenetic and causative factor of cataract. Increased concentrations of primary molecular LPO products (diene conjugates, lipid hydroperoxides, fatty acid oxy-derivatives) and end fluorescent LPO products were detected in the lipid moieties of the aqueous humor samples and human

  17. Is transcranial direct current stimulation a potential method for improving response inhibition?

    Science.gov (United States)

    Kwon, Yong Hyun; Kwon, Jung Won

    2013-04-15

    Inhibitory control of movement in motor learning requires the ability to suppress an inappropriate action, a skill needed to stop a planned or ongoing motor response in response to changes in a variety of environments. This study used a stop-signal task to determine whether transcranial direct-current stimulation over the pre-supplementary motor area alters the reaction time in motor inhibition. Forty healthy subjects were recruited for this study and were randomly assigned to either the transcranial direct-current stimulation condition or a sham-transcranial direct-current stimulation condition. All subjects consecutively performed the stop-signal task before, during, and after the delivery of anodal transcranial direct-current stimulation over the pre-supplementary motor area (pre-transcranial direct-current stimulation phase, transcranial direct-current stimulation phase, and post-transcranial direct-current stimulation phase). Compared to the sham condition, there were significant reductions in the stop-signal processing times during and after transcranial direct-current stimulation, and change times were significantly greater in the transcranial direct-current stimulation condition. There was no significant change in go processing-times during or after transcranial direct-current stimulation in either condition. Anodal transcranial direct-current stimulation was feasibly coupled to an interactive improvement in inhibitory control. This coupling led to a decrease in the stop-signal process time required for the appropriate responses between motor execution and inhibition. However, there was no transcranial direct-current stimulation effect on the no-signal reaction time during the stop-signal task. Transcranial direct-current stimulation can adjust certain behaviors, and it could be a useful clinical intervention for patients who have difficulties with response inhibition.

  18. Urocortin2 prolongs action potential duration and modulates potassium currents in guinea pig myocytes and HEK293 cells.

    Science.gov (United States)

    Yang, Li-Zhen; Zhu, Yi-Chun

    2015-07-05

    We previously reported that activation of corticotropin releasing factor receptor type 2 by urocortin2 up-regulates both L-type Ca(2+) channels and intracellular Ca(2+) concentration in ventricular myocytes and plays an important role in cardiac contractility and arrhythmogenesis. This study goal was to further test the hypothesis that urocortin2 may modulate action potentials as well as rapidly and slowly activating delayed rectifier potassium currents. With whole cell patch-clamp techniques, action potentials and slowly activating delayed rectifier potassium currents were recorded in isolated guinea pig ventricular myocytes, respectively. And rapidly activating delayed rectifier potassium currents were tested in hERG-HEK293 cells. Urocortin2 produced a time- and concentration-dependent prolongation of action potential duration. The EC50 values of action potential duration and action potential duration at 90% of repolarization were 14.73 and 24.3nM respectively. The prolongation of action potential duration of urocortin2 was almost completely or partly abolished by H-89 (protein kinase A inhibitor) or KB-R7943 (Na(+)/Ca(2+) exchange inhibitor) pretreatment respectively. And urocortin2 caused reduction of rapidly activating delayed rectifier potassium currents in hERG-HEK293 cells. In addition, urocortin2 slowed the rate of slowly activating delayed rectifier potassium channel activation, and rightward shifted the threshold of slowly activating delayed rectifier potassium currents to more positive potentials. Urocortin2 prolonged action potential duration via activation of protein kinase A and Na(+)/ Ca(2+) exchange in isolated guinea pig ventricular myocytes in a time- and concentration- dependent manner. In hERG-HEK293 cells, urocortin2 reduced rapidly activating delayed rectifier potassium current density which may contribute to action potential duration prolongation. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. 45-FOOT HIGH DROP TOWER

    Data.gov (United States)

    Federal Laboratory Consortium — The Drop Tower is used to simulate and measure the impact shocks that are exerted on parachute loads when they hit the ground. It is also used for HSL static lift to...

  20. 24 hydrocarbon degradation in poultry droppings and cassava peels

    African Journals Online (AJOL)

    OLUWOLE AKINNAGBE

    2009-01-01

    Jan 1, 2009 ... This greenhouse study was aimed at determining the potentials of poultry droppings (PD) and cassava peels ... shift in the composition of bacterial community to ..... Oil and Gas Journal. pp. ... Prentice-Hall of India Private Ltd.

  1. Annual Occurrence of Meteorite-Dropping Fireballs

    Science.gov (United States)

    Konovalova, Natalia; Jopek, Tadeusz J.

    2016-07-01

    The event of Chelyabinsk meteorite has brought about change the earlier opinion about limits of the sizes of potentially dangerous asteroidal fragments that crossed the Earth's orbit and irrupted in the Earth's atmosphere making the brightest fireball. The observations of the fireballs by fireball networks allows to get the more precise data on atmospheric trajectories and coordinates of predicted landing place of the meteorite. For the reason to search the periods of fireball activity is built the annual distribution of the numbers of meteorites with the known fall dates and of the meteorite-dropping fireballs versus the solar longitude. The resulting profile of the annual activity of meteorites and meteorite-dropping fireballs shows several periods of increased activity in the course of the year. The analysis of the atmospheric trajectories and physical properties of sporadic meteorite-dropping fireballs observed in Tajikistan by instrumental methods in the summer‒autumn periods of increased fireballs activity has been made. As a result the structural strength, the bulk density and terminal mass of the studied fireballs that can survive in the Earth atmosphere and became meteorites was obtained. From the photographic IAU MDC_2003 meteor database and published sources based on the orbit proximity as determined by D-criterion of Southworth and Hawkins the fireballs that could be the members of group of meteorite-dropping fireballs, was found. Among the near Earth's objects (NEOs) the searching for parent bodies for meteorite-dropping fireballs was made and the evolution of orbits of these objects in the past on a long interval of time was investigated.

  2. Differential roles of two delayed rectifier potassium currents in regulation of ventricular action potential duration and arrhythmia susceptibility.

    Science.gov (United States)

    Devenyi, Ryan A; Ortega, Francis A; Groenendaal, Willemijn; Krogh-Madsen, Trine; Christini, David J; Sobie, Eric A

    2017-04-01

    Arrhythmias result from disruptions to cardiac electrical activity, although the factors that control cellular action potentials are incompletely understood. We combined mathematical modelling with experiments in heart cells from guinea pigs to determine how cellular electrical activity is regulated. A mismatch between modelling predictions and the experimental results allowed us to construct an improved, more predictive mathematical model. The balance between two particular potassium currents dictates how heart cells respond to perturbations and their susceptibility to arrhythmias. Imbalances of ionic currents can destabilize the cardiac action potential and potentially trigger lethal cardiac arrhythmias. In the present study, we combined mathematical modelling with information-rich dynamic clamp experiments to determine the regulation of action potential morphology in guinea pig ventricular myocytes. Parameter sensitivity analysis was used to predict how changes in ionic currents alter action potential duration, and these were tested experimentally using dynamic clamp, a technique that allows for multiple perturbations to be tested in each cell. Surprisingly, we found that a leading mathematical model, developed with traditional approaches, systematically underestimated experimental responses to dynamic clamp perturbations. We then re-parameterized the model using a genetic algorithm, which allowed us to estimate ionic current levels in each of the cells studied. This unbiased model adjustment consistently predicted an increase in the rapid delayed rectifier K + current and a drastic decrease in the slow delayed rectifier K + current, and this prediction was validated experimentally. Subsequent simulations with the adjusted model generated the clinically relevant prediction that the slow delayed rectifier is better able to stabilize the action potential and suppress pro-arrhythmic events than the rapid delayed rectifier. In summary, iterative coupling of

  3. Assessing current and future techno-economic potential of concentrated solar power and photovoltaic electricity generation

    NARCIS (Netherlands)

    Köberle, Alexandre C.; Gernaat, David E H J; van Vuuren, Detlef P.

    2015-01-01

    CSP and PV technologies represent energy sources with large potentials. We present cost-supply curves for both technologies using a consistent methodology for 26 regions, based on geoexplicit information on solar radiation, land cover type and slope, exploring individual potential and

  4. 2D potential structures induced by RF sheaths coupled with transverse currents in front of ICRH antenna

    International Nuclear Information System (INIS)

    Faudot, E.; Heuraux, S.; Colas, L.

    2004-01-01

    Sheaths are space charge regions at the plasma-wall. They are induced by the differential inertia between ions and electrons, and without external perturbation, they create a floating potential between the neutral plasma and the walls. In Tokamaks, these sheaths are locally enhanced by the RF (radiofrequency) electric field generated by the ICRF (ion cyclotron resonance frequency) antennas used to heat magnetic fusion plasmas at very high temperature. RF sheaths are located at the connection points of magnetic field lines to the wall, or to the bumpers which protect the antenna or to any part of the antenna structure. The asymmetric behaviour of these oscillating sheaths rectifies RF potentials in the plasma in front of antenna, to finally create nonlinearly a DC potential which can be much higher than the floating potential. We study specifically how the space-time distribution of these RF and DC rectified potentials is modified when nearby flux tubes are allowed to exchange perpendicular polarization current. To simulate that, a 2-dimensional (2D) fluid code has been implemented to compute the 2D RF potential map in a plane perpendicular to magnetic lines, and within the flute approximation the whole 3-dimensional potential map is deduced. In simulation, we consider a homogeneous transverse conductivity and use a 'test' potential map having, in absence of transverse currents, a Gaussian shape characterized by its width r 0 and its amplitude φ 0 . As a function of these 2 parameters (normalized respectively to a characteristic length for transverse transport and to the local temperature), we can estimate the peaking and the smoothing of the potential structure in the presence of polarization current. So, we are able to determine, for typical plasmas, the amplitude of DC potential peaks, particularly on antenna's corners, where hot spots appear during a shot. In Tore-supra conditions near antenna corners, potential structures that are shorter than 1 centimeter are

  5. 2D potential structures induced by RF sheaths coupled with transverse currents in front of ICRH antenna

    International Nuclear Information System (INIS)

    Faudot, E.; Heuraux, S.; Colas, L.

    2004-01-01

    Sheaths are space charge regions at the plasma-wall. They are induced by the differential inertia between ions and electrons, and without external perturbation, they create a floating potential between the neutral plasma and the walls. In tokamaks, these sheaths are locally enhanced by the RF (radiofrequency) electric field generated by the ICRF (ion cyclotron resonance frequency) antennas used to heat magnetic fusion plasmas at very high temperature. RF sheaths are located at the connection points of magnetic field lines to the wall, or to the bumpers which protect the antenna or to any part of the antenna structure. The asymmetric behaviour of these oscillating sheaths rectifies RF potentials in the plasma in front of antenna, to finally create nonlinearly a DC potential which can be much higher than the floating potential. We study specifically how the space-time distribution of these RF and DC rectified potentials is modified when nearby flux tubes are allowed to exchange perpendicular polarization current. To simulate that, a 2D (2-dimensional) fluid code has been implemented to compute the 2D RF potential map in a plane perpendicular to magnetic lines, and within the flute approximation the whole 3-dimensional potential map is deduced. In simulation, we consider a homogeneous transverse conductivity and use a 'test' potential map having, in absence of transverse currents, a Gaussian shape characterized by its width r0 and its amplitude φ 0 . As a function of these 2 parameters (normalized respectively to a characteristic length for transverse transport and to the local temperature), we can estimate the peaking and the smoothing of the potential structure in the presence of polarization current. So, we are able to determine, for typical plasmas, the amplitude of DC potential peaks, particularly on antenna's corners, where hot spots appear during a shot. In typical Tore Supra conditions near antenna corners potential structures less than centimetric are

  6. Assessement of rheumatic diseases with computational radiology: current status and future potential

    DEFF Research Database (Denmark)

    Peloschek, Philipp; Boesen, Mikael; Donner, Rene

    2009-01-01

    In recent years, several computational image analysis methods to assess disease progression in rheumatic diseases were presented. This review article explains the basics of these methods as well as their potential application in rheumatic disease monitoring, it covers radiography, sonography...

  7. Energy Yield Potential Estimation Using Marine Current Turbine Simulations for the Bosphorus

    DEFF Research Database (Denmark)

    Yazicioglu, Hasan; Tunc, K. M. Murat; Ozbek, Muammer

    2017-01-01

    . The differences in elevation and salinity ratios between these two seas cause strong underwater currents. Depending on the morphology of the canal the speed of the flow varies and at some specific locations the energy intensity reaches to sufficient levels where electricity generation by marine current turbines...... becomes economically feasible. In this study, several simulations are performed for a 10 MW marine turbine farm/ cluster whose location is selected by taking into account several factors such as the canal morphology, current speed and passage of vessels. 360 different simulations are performed for 15...... within the selected region, the analyses are performed for three different flow speeds corresponding to 10 % increase and decrease in the average value. For each simulation the annual energy yield and cluster efficiency are calculated....

  8. A horizon scanning assessment of current and potential future threats to migratory shorebirds

    Science.gov (United States)

    Sutherland, William J.; Alves, José A.; Amano, Tatsuya; Chang, Charlotte H.; Davidson, Nicholas C.; Finlayson, C. Max; Gill, Jennifer A.; Gill, Robert E.; González, Patricia M.; Gunnarsson, Tómas Grétar; Kleijn, David; Spray, Chris J.; Székely, Tamás; Thompson, Des B.A.

    2012-01-01

    We review the conservation issues facing migratory shorebird populations that breed in temperate regions and use wetlands in the non-breeding season. Shorebirds are excellent model organisms for understanding ecological, behavioural and evolutionary processes and are often used as indicators of wetland health. A global team of experienced shorebird researchers identified 45 issues facing these shorebird populations, and divided them into three categories (natural, current anthropogenic and future issues). The natural issues included megatsunamis, volcanoes and regional climate changes, while current anthropogenic threats encompassed agricultural intensification, conversion of tidal flats and coastal wetlands by human infrastructure developments and eutrophication of coastal systems. Possible future threats to shorebirds include microplastics, new means of recreation and infectious diseases. We suggest that this review process be broadened to other taxa to aid the identification and ranking of current and future conservation actions.

  9. Climate Analogues Suggest Limited Potential for Intensification of Production on Current Croplands Under Climate Change

    Science.gov (United States)

    Pugh, T. A. M.; Mueller, C.; Elliott, J.; Deryng, D.; Folberth, C.; Olin, S.; Schmid, E.; Arneth, A.

    2016-01-01

    Climate change could pose a major challenge to efforts towards strongly increase food production over the coming decades. However, model simulations of future climate-impacts on crop yields differ substantially in the magnitude and even direction of the projected change. Combining observations of current maximum-attainable yield with climate analogues, we provide a complementary method of assessing the effect of climate change on crop yields. Strong reductions in attainable yields of major cereal crops are found across a large fraction of current cropland by 2050. These areas are vulnerable to climate change and have greatly reduced opportunity for agricultural intensification. However, the total land area, including regions not currently used for crops, climatically suitable for high attainable yields of maize, wheat and rice is similar by 2050 to the present-day. Large shifts in land-use patterns and crop choice will likely be necessary to sustain production growth rates and keep pace with demand.

  10. Drop Spreading with Random Viscosity

    Science.gov (United States)

    Xu, Feng; Jensen, Oliver

    2016-11-01

    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  11. Thermocapillary reorientation of Janus drops

    Science.gov (United States)

    Rosales, Rodolfo; Saenz, Pedro

    2017-11-01

    Janus drops, named after the Ancient Roman two-faced god, are liquid drops formed from two immiscible fluids. Experimental observations indicate that a Janus drop may re-orientate in response to an applied external thermal gradient due to the Marangoni effect. Depending on the angle between the interior interface and the direction of the temperature gradient, disparities in the physical properties of the constituent liquids may lead to asymmetries in the thermocapillary flow. As a result, the drop will move along a curved path until a torque-free configuration is achieved, point after which it will continue on a straight trajectory. Here, we present the results of a theoretical investigation of this realignment phenomenon in the Stokes regime and in the limit of non-deformable interfaces. A 3D semi-analytical method in terms of polar spherical harmonics is developed to characterize and rationalize the hydrodynamic response (forces and torques), flow (velocity and temperature distribution) and trajectory of a Janus drop moving during the temperature-driven reorientation process. Furthermore, we discuss how this phenomenon may be exploited to develop dynamically reconfigurable micro-lenses. This work was partially supported by the US National Science Foundation through Grants DMS-1614043 and DMS-1719637.

  12. Negative-ion current density dependence of the surface potential of insulated electrode during negative-ion implantation

    International Nuclear Information System (INIS)

    Tsuji, Hiroshi; Okayama, Yoshio; Toyota, Yoshitaka; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki; Tanjyo, Masayasu; Matsuda, Kouji.

    1994-01-01

    Positive ion implantation has been utilized as the method of impurity injection in ultra-LSI production, but the problem of substrate charging cannot be resolved by conventional charge compensation method. It was forecast that by negative ion implantation, this charging problem can be resolved. Recently the experiment on the negative ion implantation into insulated electrodes was carried out, and the effect of negative ion implantation to this problem was proved. However, the dependence of charged potential on the increase of negative ion current at the time of negative ion implantation is a serious problem in large current negative ion implantation hereafter. The charged potential of insulated conductor substrates was measured by the negative ion implantation using the current up to several mA/cm 2 . The experimental method is explained. Medium current density and high current density negative ion implantation and charged potential are reported. Accordingly in negative ion implantation, if current density is optimized, the negative ion implantation without charging can be realized. (K.I.)

  13. Potential for small-diameter sawtimber utilization by the current sawmill industry in western North America.

    Science.gov (United States)

    Francis G. Wagner; Charles E. Keegan; Roger D. Fight; Susan. Willits

    1998-01-01

    New silvicultural prescriptions for ecosystem management on both public and private timberlands in western North America will likely result in an influx of relatively small-diameter sawtimber for processing. Since sawmills currently process a majority of sawtimber harvested in western North America (more than 80% in some regions), this study concentrated on...

  14. Atlas of current and potential future distributions of common trees of the eastern United States

    Science.gov (United States)

    Louis R. Iverson; Anantha M. Prasad; Betsy J. Hale; Elaine Kennedy Sutherland

    1999-01-01

    This atlas documents the current and possible future distribution of 80 common tree species in the Eastern United States and gives detailed information on environmental characteristics defining these distributions. Also included are outlines of life history characteristics and summary statistics for these species. Much of the data are derived from Forest Inventory and...

  15. Gasification of solid waste — potential and application of co-current moving bed gasifiers

    NARCIS (Netherlands)

    Groeneveld, M.J.; van Swaaij, Willibrordus Petrus Maria

    1979-01-01

    A review is given of gasification processes for solid fuels with special emphasis on waste gasification. Although the co-current moving bed gasifier has not been under consideration for a long time, it offers interesting possibilities for waste gasification. Some operational data are given. Two

  16. Towards Current Profile Control in ITER: Potential Approaches and Research Needs

    Science.gov (United States)

    Schuster, E.; Barton, J. E.; Wehner, W. P.

    2014-10-01

    Many challenging plasma control problems still need to be addressed in order for the ITER Plasma Control System (PCS) to be able to successfully achieve the ITER project goals. For instance, setting up a suitable toroidal current density profile is key for one possible advanced scenario characterized by noninductive sustainment of the plasma current and steady-state operation. The nonlinearity and high dimensionality exhibited by the plasma demand a model-based current-profile control synthesis procedure that can accommodate this complexity through embedding the known physics within the design. The development of a model capturing the dynamics of the plasma relevant for control design enables not only the design of feedback controllers for regulation or tracking but also the design of optimal feedforward controllers for a systematic model-based approach to scenario planning, the design of state estimators for a reliable real-time reconstruction of the plasma internal profiles based on limited and noisy diagnostics, and the development of a fast predictive simulation code for closed-loop performance evaluation before implementation. Progress towards control-oriented modeling of the current profile evolution and associated control design has been reported following both data-driven and first-principles-driven approaches. An overview of these two approaches will be provided, as well as a discussion on research needs associated with each one of the model applications described above. Supported by the US Department of Energy under DE-SC0001334 and DE-SC0010661.

  17. Modeling fire-driven deforestation potential in Amazonia under current and projected climate conditions

    NARCIS (Netherlands)

    Le Page, Y.; van der Werf, G.R.; Morton, D.C.; Pereira, J.M.C.

    2010-01-01

    Fire is a widely used tool to prepare deforested areas for agricultural use in Amazonia. Deforestation is currently concentrated in seasonal forest types along the arc of deforestation, where dry-season conditions facilitate burning of clear-felled vegetation. Interior Amazon forests, however, are

  18. A current sensor based on the giant magnetoresistance effect: design and potential smart grid applications.

    Science.gov (United States)

    Ouyang, Yong; He, Jinliang; Hu, Jun; Wang, Shan X

    2012-11-09

    Advanced sensing and measurement techniques are key technologies to realize a smart grid. The giant magnetoresistance (GMR) effect has revolutionized the fields of data storage and magnetic measurement. In this work, a design of a GMR current sensor based on a commercial analog GMR chip for applications in a smart grid is presented and discussed. Static, dynamic and thermal properties of the sensor were characterized. The characterizations showed that in the operation range from 0 to ±5 A, the sensor had a sensitivity of 28 mV·A(-1), linearity of 99.97%, maximum deviation of 2.717%, frequency response of −1.5 dB at 10 kHz current measurement, and maximum change of the amplitude response of 0.0335%·°C(-1) with thermal compensation. In the distributed real-time measurement and monitoring of a smart grid system, the GMR current sensor shows excellent performance and is cost effective, making it suitable for applications such as steady-state and transient-state monitoring. With the advantages of having a high sensitivity, high linearity, small volume, low cost, and simple structure, the GMR current sensor is promising for the measurement and monitoring of smart grids.

  19. ABCXYZ: vector potential (A) and magnetic field (B) code (C) for Cartesian (XYZ) geometry using general current elements

    International Nuclear Information System (INIS)

    Anderson, D.V.; Breazeal, J.; Finan, C.H.; Johnston, B.M.

    1976-01-01

    ABCXYZ is a computer code for obtaining the Cartesian components of the vector potential and the magnetic field on an observed grid from an arrangement of current-carrying wires. Arbitrary combinations of straight line segments, arcs, and loops are allowed in the specification of the currents. Arbitrary positions and orientations of the current-carrying elements are also allowed. Specification of the wire diameter permits the computation of well-defined fields, even in the interiors of the conductors. An optical feature generates magnetic field lines. Extensive graphical and printed output is available to the user including contour, grid-line, and field-line plots. 12 figures, 1 table

  20. The effect of ultraviolet on direct current potentials of the human skin

    Directory of Open Access Journals (Sweden)

    A. O. Lazarev

    2017-01-01

    Full Text Available Aim of the study. investigation of the suntan on the level of omnipresent electrical potential of skin in frames of development of the hypothesis about the melanocyte participation in skin electrical activity formation. Material and methods. 11 men and 11 women on summer holyday took part in investigation. The relationship between the levels of skin omnipresent electrical potential and the reflection factor were investigated. The omnipresent electrical potentials were registered as the potential differences between the two areas on skin using the Orion 261S pH meter and the liquid Ag/AgCl electrodes of the same company. The reflecting factor was estimated with the help of the spectroradiometer LI-1800 (“LI-COR” using the included intgrational sphere 1800-12 coated with barium sulfate. Hole size was 1,45 cm. The reflection factor was estimated at the wave band 375-800 nanometers with the scanning pitch 1 nm. Main results. There is a mathematical relation between the magnitudes of potential differences and the reflection factors of the areas of sunburnt skin and the areas of the skin not affected with sun at wave light 620-729 nm. The relationship could be approximated in linear equation. Spearman correlation factor between these two parameters was -0,43 (p = 0,045, between the differences in levels of skin omnipresent electrical potential and the reflection factors of the sunburnt skin was r = -0,52 (p = 0,01, between the differences of the electrical potentials of sunburnt skin and the skin not affected with sun was r = -0,28 (p = 0,2. The presented results of investigation and the data from literature allow to conclude that there is a positive correlation between the level of omnipresent electrical potential of skin and the quantity of melanosomes filled with melanin. Conclusion. It is suggested that melanocytes take part in formation of the skin electrical activity via melanosomes filled with melanin. At the same time the melanocyte

  1. Assessement of rheumatic diseases with computational radiology: Current status and future potential

    International Nuclear Information System (INIS)

    Peloschek, Philipp; Boesen, Mikael; Donner, Rene; Kubassova, Olga; Birngruber, Erich; Patsch, Janina; Mayerhoefer, Marius; Langs, Georg

    2009-01-01

    In recent years, several computational image analysis methods to assess disease progression in rheumatic diseases were presented. This review article explains the basics of these methods as well as their potential application in rheumatic disease monitoring, it covers radiography, sonography as well as magnetic resonance imaging in quantitative analysis frameworks.

  2. Acoustic Noise Alters Selective Attention Processes as Indicated by Direct Current (DC) Brain Potential Changes

    OpenAIRE

    Trimmel, Karin; Schätzer, Julia; Trimmel, Michael

    2014-01-01

    Acoustic environmental noise, even of low to moderate intensity, is known to adversely affect information processing in animals and humans via attention mechanisms. In particular, facilitation and inhibition of information processing are basic functions of selective attention. Such mechanisms can be investigated by analyzing brain potentials under conditions of externally directed attention (intake of environmental information) versus internally directed attention (rejection of environmental ...

  3. The Development of B2C E-Commerce in Greece: Current Situation and Future Potential.

    Science.gov (United States)

    Kardaras, Dimitris; Papathanassiou, Eleutherios

    2000-01-01

    Reports on the results of a survey of 120 companies in Greece that evaluated the potential of business to customer (B2C) Internet applications and investigated how the Internet and e-commerce can offer new opportunities for businesses to improve their customers' satisfaction. Discusses electronic commerce problems and future technology. (Contains…

  4. Eye-Drops for Activation of DREADDs

    Directory of Open Access Journals (Sweden)

    William T. Keenan

    2017-11-01

    Full Text Available Designer Receptors Exclusively Activated by Designer Drugs (DREADDs are an important tool for modulating and understanding neural circuits. Depending on the DREADD system used, DREADD-targeted neurons can be activated or repressed in vivo following a dose of the DREADD agonist clozapine-N-oxide (CNO. Because DREADD experiments often involve behavioral assays, the method of CNO delivery is important. Currently, the most common delivery method is intraperitoneal (IP injection. IP injection is both a fast and reliable technique, but it is painful and stressful particularly when many injections are required. We sought an alternative CNO delivery paradigm, which would retain the speed and reliability of IP injections without being as invasive. Here, we show that CNO can be effectively delivered topically via eye-drops. Eye-drops robustly activated DREADD-expressing neurons in the brain and peripheral tissues and does so at the same dosages as IP injection. Eye-drops provide an easier, less invasive and less stressful method for activating DREADDs in vivo.

  5. Tidal Stream Generators, current state and potential opportunities for condition monitoring

    DEFF Research Database (Denmark)

    Kappatos, Vassilios; Georgoulas, George; Avdelidis, Nicolas

    2016-01-01

    Tidal power industry has made significant progress towards commercialization over the past decade. Significant investments from sector leaders, strong technical progress and positive media coverage have established the credibility of this specific renewable energy source. However, its progress...... is being retarded by operation and maintenance problems, which results in very low operational availability times, as low as 25 %. This paper presents a literature review of the current state of tidal device operators as well as some commercial tidal turbine condition monitoring solutions. Furthermore......, an overview is given of the global tidal activity status (tidal energy market size and geography), the key industry activity and the regulations-standards related with tidal energy industry. Therefore, the main goal of this paper is to provide a bird’s view of the current status of the tidal power industry...

  6. Interfacial Instabilities in Evaporating Drops

    Science.gov (United States)

    Moffat, Ross; Sefiane, Khellil; Matar, Omar

    2007-11-01

    We study the effect of substrate thermal properties on the evaporation of sessile drops of various liquids. An infra-red imaging technique was used to record the interfacial temperature. This technique illustrates the non-uniformity in interfacial temperature distribution that characterises the evaporation process. Our results also demonstrate that the evaporation of methanol droplets is accompanied by the formation of wave-trains in the interfacial temperature field; similar patterns, however, were not observed in the case of water droplets. More complex patterns are observed for FC-72 refrigerant drops. The effect of substrate thermal conductivity on the structure of the complex pattern formation is also elucidated.

  7. Review of comparative LCAs of food waste management systems – Current status and potential improvements

    International Nuclear Information System (INIS)

    Bernstad, A.; Cour Jansen, J. la

    2012-01-01

    Highlights: ► GHG-emissions from different treatment alternatives vary largely in 25 reviewed comparative LCAs of bio-waste management. ► System-boundary settings often vary largely in reviewed studies. ► Existing LCA guidelines give varying recommendations in relation to several key issues. - Abstract: Twenty-five comparative cycle assessments (LCAs) addressing food waste treatment were reviewed, including the treatment alternatives landfill, thermal treatment, compost (small and large scale) and anaerobic digestion. The global warming potential related to these treatment alternatives varies largely amongst the studies. Large differences in relation to setting of system boundaries, methodological choices and variations in used input data were seen between the studies. Also, a number of internal contradictions were identified, many times resulting in biased comparisons between alternatives. Thus, noticed differences in global warming potential are not found to be a result of actual differences in the environmental impacts from studied systems, but rather to differences in the performance of the study. A number of key issues with high impact on the overall global warming potential from different treatment alternatives for food waste were identified through the use of one-way sensitivity analyses in relation to a previously performed LCA of food waste management. Assumptions related to characteristics in treated waste, losses and emissions of carbon, nutrients and other compounds during the collection, storage and pretreatment, potential energy recovery through combustion, emissions from composting, emissions from storage and land use of bio-fertilizers and chemical fertilizers and eco-profiles of substituted goods were all identified as highly relevant for the outcomes of this type of comparisons. As the use of LCA in this area is likely to increase in coming years, it is highly relevant to establish more detailed guidelines within this field in order to

  8. Review of comparative LCAs of food waste management systems - Current status and potential improvements

    Energy Technology Data Exchange (ETDEWEB)

    Bernstad, A., E-mail: anna.bernstad@chemeng.lth.se [Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, Chemical Centre, 221 00 Lund (Sweden); Cour Jansen, J. la [Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, Chemical Centre, 221 00 Lund (Sweden)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer GHG-emissions from different treatment alternatives vary largely in 25 reviewed comparative LCAs of bio-waste management. Black-Right-Pointing-Pointer System-boundary settings often vary largely in reviewed studies. Black-Right-Pointing-Pointer Existing LCA guidelines give varying recommendations in relation to several key issues. - Abstract: Twenty-five comparative cycle assessments (LCAs) addressing food waste treatment were reviewed, including the treatment alternatives landfill, thermal treatment, compost (small and large scale) and anaerobic digestion. The global warming potential related to these treatment alternatives varies largely amongst the studies. Large differences in relation to setting of system boundaries, methodological choices and variations in used input data were seen between the studies. Also, a number of internal contradictions were identified, many times resulting in biased comparisons between alternatives. Thus, noticed differences in global warming potential are not found to be a result of actual differences in the environmental impacts from studied systems, but rather to differences in the performance of the study. A number of key issues with high impact on the overall global warming potential from different treatment alternatives for food waste were identified through the use of one-way sensitivity analyses in relation to a previously performed LCA of food waste management. Assumptions related to characteristics in treated waste, losses and emissions of carbon, nutrients and other compounds during the collection, storage and pretreatment, potential energy recovery through combustion, emissions from composting, emissions from storage and land use of bio-fertilizers and chemical fertilizers and eco-profiles of substituted goods were all identified as highly relevant for the outcomes of this type of comparisons. As the use of LCA in this area is likely to increase in coming years, it is highly

  9. Is transcranial direct current stimulation a potential method for improving response inhibition?☆

    OpenAIRE

    Kwon, Yong Hyun; Kwon, Jung Won

    2013-01-01

    Inhibitory control of movement in motor learning requires the ability to suppress an inappropriate action, a skill needed to stop a planned or ongoing motor response in response to changes in a variety of environments. This study used a stop-signal task to determine whether transcranial direct-current stimulation over the pre-supplementary motor area alters the reaction time in motor inhibition. Forty healthy subjects were recruited for this study and were randomly assigned to either the tran...

  10. Prehospital Ultrasound in Trauma: A Review of Current and Potential Future Clinical Applications

    Directory of Open Access Journals (Sweden)

    Tharwat El Zahran

    2018-01-01

    Full Text Available Ultrasound (US is an essential tool for evaluating trauma patients in the hospital setting. Many previous in-hospital studies have been extrapolated to out of hospital setting to improve diagnostic accuracy in prehospital and austere environments. This review article presents the role of prehospital US in blunt and penetrating trauma management with emphasis on its current clinical applications, challenges, and future implications of such use.

  11. Potentiality of fast wave current drive in non-maxwellian plasmas

    International Nuclear Information System (INIS)

    Moreau, D.; O'Brien, M.R.; Cox, M.; Start, D.F.H.

    1987-06-01

    After a short analysis of the available experimental data on pure fast wave electron current drive we propose a theoretical scaling law for the wave absorption through combined electron Landau damping and transit time magnetic pumping. We then present the result of a fully relativistic calculation which we apply to a bi-Maxwellian electron distribution function and conclude on the requirements to be fulfilled by the energetic tail for obtaining significant damping in Tore-Supra

  12. Potential effects of current drug therapies on cognitive impairment in patients with type 2 diabetes.

    Science.gov (United States)

    Palleria, Caterina; Leporini, Christian; Maida, Francesca; Succurro, Elena; De Sarro, Giovambattista; Arturi, Franco; Russo, Emilio

    2016-07-01

    Type 2 diabetes mellitus is a complex metabolic disease that can cause serious damage to various organs. Among the best-known complications, an important role is played by cognitive impairment. Impairment of cognitive functioning has been reported both in type 1 and 2 diabetes mellitus. While this comorbidity has long been known, no major advances have been achieved in clinical research; it is clear that appropriate control of blood glucose levels represents the best current (although unsatisfactory) approach in the prevention of cognitive impairment. We have focused our attention on the possible effect on the brain of antidiabetic drugs, despite their effects on blood glucose levels, giving a brief rationale on the mechanisms (e.g. GLP-1, BDNF, ghrelin) that might be involved. Indeed, GLP-1 agonists are currently clinically studied in other neurodegenerative diseases (i.e. Parkinson's and Alzheimer's disease); furthermore, also other antidiabetic drugs have proven efficacy in preclinical studies. Overall, promising results are already available and finding new intervention strategies represents a current need in this field of research. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. The current bioenergy production potential of semi-arid and arid regions in sub-Saharan Africa

    NARCIS (Netherlands)

    Wicke, B.; Smeets, E.M.W.; Watson, H.; Faaij, A.P.C.

    2011-01-01

    This article assesses the current technical and economic potential of three bioenergy production systems (cassava ethanol, jatropha oil and fuelwood) in semi-arid and arid regions of eight sub-Saharan African countries. The results indicate that the availability of land for energy production ranges

  14. Shared Solar: Current Landscape, Market Potential, and the Impact of Federal Securities Regulation; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-05-27

    This presentation provides a high-level overview of the current U.S. shared solar landscape, the impact that a given shared solar program's structure has on requiring federal securities oversight, as well as an estimate of market potential for U.S. shared solar deployment.

  15. Will dragonblood survive the next period of climate change? Current and future potential distribution of Dracaena cinnabari (Socotra, Yemen)

    NARCIS (Netherlands)

    Attorre, F.; Francesconi, F.; Taleb, N.; Scholte, P.; Saed, A.; Alfo, M.; Bruno, F.

    2007-01-01

    The potential impact of climate change on Dracaena cinnabari, a spectacular relict of the Mio-Pliocene Laurasian subtropical forest in Socotra (Yemen), was analysed. Current distribution, abundance and vertical structure of D. cinnabari populations were assessed with 74 plots in nine remnant areas.

  16. A Study of Second-Year Engineering Students' Alternative Conceptions about Electric Potential, Current Intensity and Ohm's Law

    Science.gov (United States)

    Periago, M. Cristina; Bohigas, Xavier

    2005-01-01

    The aim of this research was to evaluate and analyse second-year industrial engineering and chemical engineering students prior knowledge of conceptual aspects of "circuit theory". Specifically, we focused on the basic concepts of electric potential and current intensity and on the fundamental relationship between them as expressed by Ohm's law.…

  17. Estimating urban forest carbon sequestration potential in the southern United States using current remote sensing imagery sources

    Science.gov (United States)

    Krista Merry; Pete Bettinger; Jacek Siry; J. Michael Bowker

    2015-01-01

    With an increased interest in reducing carbon dioxide in the atmosphere, tree planting and maintenance in urban areas has become a viable option for increasing carbon sequestration. Methods for assessing the potential for planting trees within an urban area should allow for quick, inexpensive, and accurate estimations of available land using current remote sensing...

  18. Internal flow of acoustically levitated drops undergoing sectorial oscillations

    International Nuclear Information System (INIS)

    Shen, C.L.; Xie, W.J.; Yan, Z.L.; Wei, B.

    2010-01-01

    We present the experimental observation and theoretical analysis of fluid flow in acoustically levitated water drop undergoing sectorial oscillations. The fluid always flows between the extended sections and the compressed sections. The magnitude of fluid velocity decreases from the equatorial fringe to the centre of levitated drop. The maximum fluid velocity is 60-160 mm/s and the Reynolds number of the oscillations is estimated to be 137-367. The internal flow of the drop is analyzed as potential flow, and the fluid velocity is found to be horizontal. In the equatorial plane, the calculated stream lines and velocity profiles agree well with the experimental observations.

  19. Analytical Evaluation of Preliminary Drop Tests Performed to Develop a Robust Design for the Standardized DOE Spent Nuclear Fuel Canister

    International Nuclear Information System (INIS)

    Ware, A.G.; Morton, D.K.; Smith, N.L.; Snow, S.D.; Rahl, T.E.

    1999-01-01

    The Department of Energy (DOE) has developed a design concept for a set of standard canisters for the handling, interim storage, transportation, and disposal in the national repository, of DOE spent nuclear fuel (SNF). The standardized DOE SNF canister has to be capable of handling virtually all of the DOE SNF in a variety of potential storage and transportation systems. It must also be acceptable to the repository, based on current and anticipated future requirements. This expected usage mandates a robust design. The canister design has four unique geometries, with lengths of approximately 10 feet or 15 feet, and an outside nominal diameter of 18 inches or 24 inches. The canister has been developed to withstand a drop from 30 feet onto a rigid (flat) surface, sustaining only minor damage - but no rupture - to the pressure (containment) boundary. The majority of the end drop-induced damage is confined to the skirt and lifting/stiffening ring components, which can be removed if de sired after an accidental drop. A canister, with its skirt and stiffening ring removed after an accidental drop, can continue to be used in service with appropriate operational steps being taken. Features of the design concept have been proven through drop testing and finite element analyses of smaller test specimens. Finite element analyses also validated the canister design for drops onto a rigid (flat) surface for a variety of canister orientations at impact, from vertical to 45 degrees off vertical. Actual 30-foot drop testing has also been performed to verify the final design, though limited to just two full-scale test canister drops. In each case, the analytical models accurately predicted the canister response

  20. The dependence of potential well formation on the magnetic field strength and electron injection current in a polywell device

    International Nuclear Information System (INIS)

    Cornish, S.; Gummersall, D.; Carr, M.; Khachan, J.

    2014-01-01

    A capacitive probe has been used to measure the plasma potential in a polywell device in order to observe the dependence of potential well formation on magnetic field strength, electron injection current, and polywell voltage bias. The effectiveness of the capacitive probe in a high energy electron plasma was determined by measuring the plasma potential of a planar diode with an axial magnetic field. The capacitive probe was translated along the axis of one of the field coils of the polywell, and the spatial profile of the potential well was measured. The confinement time of electrons in the polywell was estimated with a simple analytical model which used the experimentally observed potential well depths, as well as a simulation of the electron trajectories using particle orbit theory

  1. Current organic waste recycling and the potential for local recycling through urban agriculture in Metro Manila.

    Science.gov (United States)

    Hara, Yuji; Furutani, Takashi; Murakami, Akinobu; Palijon, Armando M; Yokohari, Makoto

    2011-11-01

    Using the solid waste management programmes of three barangays (the smallest unit of local government in the Philippines) in Quezon City, Metro Manila, as a case study, this research aimed to further the development of efficient organic waste recycling systems through the promotion of urban agricultural activities on green and vacant spaces. First, the quantity of organic waste and compost produced through ongoing barangay projects was measured. The amount of compost that could potentially be utilized on farmland and vacant land within the barangays was then identified to determine the possibility of a local recycling system. The results indicate that, at present, securing buyers for compost is difficult and, therefore, most compost is distributed to large neighbouring farm villages. However, the present analysis of potential compost use within the barangay demonstrates that a more local compost recycling system is indeed feasible.

  2. Factors influencing academic library users' intention to use mobile systems:A comparison of current users and potential adopters

    Institute of Scientific and Technical Information of China (English)

    Haijuan YANG; Sisi GUI

    2014-01-01

    Purpose:The study intends to examine the factors influencing the behavioral intention to use academic libraries' mobile systems from the perspective of current users and potential adopters,respectively.Design/methodology/approach:Our study investigates the mobile library system's acceptance by using a context-specific extension of the theory of reasoned action (TRA) and the technology acceptance model (TAM),which includes such factors as mobile self-efficacy,personal innovativeness and perceived playfulness.Structural equation modeling was used to test the validity of the proposed model based on the empirical data which was collected from 210 questionnaire survey participants.Findings:The result shows that 1) for both current users and potential adopters,attitude toward use and subjective norm both have a significant and positive impact on behavioral intention to use;2) perceived usefulness and perceived ease of use are significantly correlated to potential adopters' attitude toward use whereas perceived usefulness and perceived playfulness are significantly related to current users' attitude toward use;3) as for the comparison between the two groups of users,personal innovativeness not only affects perceived usefulness of both current users and potential adopters,but also affects potential adopters' perceived playfulness positively.Mobile self-efficacy has a significant effect on perceived ease of use for both types of users.Research limitations:Although the sample size met the basic statistics requirements for the social research,the participants were mainly college students,and other mobile system users like faculty members and researchers were not investigated.In addition,some influencing factors,such as information quality,system quality and service quality were not considered in the research model.Practical implications:This study reveals main factors which influence both current users and potential adopters' intention to use the mobile system

  3. Factors influencing academic library users’ intention to use mobile systems: A comparison of current users and potential adopters

    Institute of Scientific and Technical Information of China (English)

    Haijuan; YANG; Sisi; GUI

    2014-01-01

    Purpose: The study intends to examine the factors influencing the behavioral intention to use academic libraries’ mobile systems from the perspective of current users and potential adopters, respectively. Design/methodology/approach: Our study investigates the mobile library system’s acceptance by using a context-specific extension of the theory of reasoned action(TRA) and the technology acceptance model(TAM), which includes such factors as mobile self-efficacy, personal innovativeness and perceived playfulness. Structural equation modeling was used to test the validity of the proposed model based on the empirical data which was collected from 210 questionnaire survey participants.Findings: The result shows that 1) for both current users and potential adopters, attitude toward use and subjective norm both have a significant and positive impact on behavioral intention to use; 2) perceived usefulness and perceived ease of use are significantly correlated to potential adopters’ attitude toward use whereas perceived usefulness and perceived playfulness are significantly related to current users’ attitude toward use; 3) as for the comparison between the two groups of users, personal innovativeness not only affects perceived usefulness of both current users and potential adopters, but also affects potential adopters’ perceived playfulness positively. Mobile self-efficacy has a significant effect on perceived ease of use for both types of users.Research limitations: Although the sample size met the basic statistics requirements for the social research, the participants were mainly college students, and other mobile system users like faculty members and researchers were not investigated. In addition, some influencing factors, such as information quality, system quality and service quality were not considered in the research model.Practical implications: This study reveals main factors which influence both current users and potential adopters’ intention to use

  4. [Biotechnological potential of methylotrophic bacteria: a review of current status and future prospects].

    Science.gov (United States)

    Trotsenko, Iu A; Doronina, N V; Khmelenina, V N

    2005-01-01

    Major results of the authors' findings on the implementation of biotechnological potential of aerobic methylobacteria and methanotrophs for obtaining forage proteins, biopolymers (polybutyrate and polysaccharides), enzymes (oxidoreductases), and bioprotectors (ectoin), as well as for degrading toxic C1 and Cn compounds have been reviewed. Unique features of the structural and functional organization of the metabolism of extremophilic (tolerant) methylotrophs are discussed, with a view for their prospective use in various fields of modern biotechnology, including biocatalysis and nanotechnology.

  5. Survey of current Swiss pig feeding practices and potential for ammonia emission reduction

    OpenAIRE

    Spring, P.; Bracher, A.

    2017-01-01

    Controlling potentially harmful and polluting emissions from farms is important in the developed world, where legislation exists in many countries limiting emissions such as ammonia and controlling how manure is disposed of from intensive farming operations. In Switzerland, there are legal agreements concerning controls of ammonia emissions, most especially from farms. Ammonia production from pig farms can be controlled by dietary intervention, such as reducing protein levels, which in turn r...

  6. Current View on Osteogenic Differentiation Potential of Mesenchymal Stromal Cells Derived from Placental Tissues.

    Science.gov (United States)

    Kmiecik, Gabriela; Spoldi, Valentina; Silini, Antonietta; Parolini, Ornella

    2015-08-01

    Mesenchymal stromal cells (MSC) isolated from human term placental tissues possess unique characteristics, including their peculiar immunomodulatory properties and their multilineage differentiation potential. The osteogenic differentiation capacity of placental MSC has been widely disputed, and continues to be an issue of debate. This review will briefly discuss the different MSC populations which can be obtained from different regions of human term placenta, along with their unique properties, focusing specifically on their osteogenic differentiation potential. We will present the strategies used to enhance osteogenic differentiation potential in vitro, such as through the selection of subpopulations more prone to differentiate, the modification of the components of osteo-inductive medium, and even mechanical stimulation. Accordingly, the applications of three-dimensional environments in vitro and in vivo, such as non-synthetic, polymer-based, and ceramic scaffolds, will also be discussed, along with results obtained from pre-clinical studies of placental MSC for the regeneration of bone defects and treatment of bone-related diseases.

  7. Sensitivity of Rabbit Ventricular Action Potential and Ca2+ Dynamics to Small Variations in Membrane Currents and Ion Diffusion Coefficients

    Directory of Open Access Journals (Sweden)

    Yuan Hung Lo

    2013-01-01

    Full Text Available Little is known about how small variations in ionic currents and Ca2+ and Na+ diffusion coefficients impact action potential and Ca2+ dynamics in rabbit ventricular myocytes. We applied sensitivity analysis to quantify the sensitivity of Shannon et al. model (Biophys. J., 2004 to 5%–10% changes in currents conductance, channels distribution, and ion diffusion in rabbit ventricular cells. We found that action potential duration and Ca2+ peaks are highly sensitive to 10% increase in L-type Ca2+ current; moderately influenced by 10% increase in Na+-Ca2+ exchanger, Na+-K+ pump, rapid delayed and slow transient outward K+ currents, and Cl− background current; insensitive to 10% increases in all other ionic currents and sarcoplasmic reticulum Ca2+ fluxes. Cell electrical activity is strongly affected by 5% shift of L-type Ca2+ channels and Na+-Ca2+ exchanger in between junctional and submembrane spaces while Ca2+-activated Cl−-channel redistribution has the modest effect. Small changes in submembrane and cytosolic diffusion coefficients for Ca2+, but not in Na+ transfer, may alter notably myocyte contraction. Our studies highlight the need for more precise measurements and further extending and testing of the Shannon et al. model. Our results demonstrate usefulness of sensitivity analysis to identify specific knowledge gaps and controversies related to ventricular cell electrophysiology and Ca2+ signaling.

  8. How to harness the performance potential of current multi-core processors

    International Nuclear Information System (INIS)

    Jarp, Sverre; Lazzaro, Alfio; Leduc, Julien; Nowak, Andrzej

    2011-01-01

    Leakage currents have put a stop to the semiconductor industry's ability to increase processor frequency in order to enhance the performance of new microprocessors. Instead, we observe a slew of changes inside the micro-architecture with an aim of enhancing the performance. Several of these changes, however, do not translate into automatic speed improvements for the software. This paper discusses the increased complexity of modern microprocessors by separating out into dimensions each feature that impacts performance and mentions briefly ways of improving software, in particular that of the High Energy Physics community, to take full advantage.

  9. A survey of electron Bernstein wave heating and current drive potential for spherical tokamaks

    Czech Academy of Sciences Publication Activity Database

    Urban, Jakub; Decker, J.; Peysson, Y.; Preinhaelter, Josef; Shevchenko, V.; Taylor, G.; Vahala, L.; Vahala, G.

    2011-01-01

    Roč. 51, č. 8 (2011), 083050-083050 ISSN 0029-5515 R&D Projects: GA ČR GA202/08/0419; GA MŠk 7G10072 Institutional research plan: CEZ:AV0Z20430508 Keywords : spherical tokamak * electron Bernstein wave (EBW) * heating * current drive * electron cyclotron wave Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.090, year: 2011 http://iopscience.iop.org/0029-5515/51/8/083050/pdf/0029-5515_51_8_083050.pdf

  10. Transcranial Alternating Current Stimulation: A potential risk for genetic generalized epilepsy patients (Study Case

    Directory of Open Access Journals (Sweden)

    Daniel San Juan Orta

    2016-11-01

    Full Text Available Transcranial alternating current stimulation (tACS is a re-emergent neuromodulation technique that consists in the external application of oscillating electrical currents that induces changes in cortical excitability. We present the case of a 16-year-old female with pharmaco-resistant juvenile myoclonic epilepsy to three antiepileptic’s drugs characterized by four myoclonic and 20 absence seizures monthly. She received tACS at 1mA@3Hz pulse train during 60 minutes over Fp1-Fp2 (10-20 EEG international system position during 4 consecutive days using an Endeavor™ IOM Systems device® (Natus Medical Incorporated, Middleton, WI, USA. At the one-month follow-up, she reported a 75% increase in seizures frequency (only myoclonic and tonic-clonic events and developed a 24h myoclonic status epilepticus that resolved with oral clonazepam and intravenous valproate. At the two-month follow-up, the patient reported a 15-day seizure-free period.

  11. Smart grids in the colombian electric system: Current situation and potential opportunities

    Directory of Open Access Journals (Sweden)

    William Mauricio Giral Ramírez

    2017-07-01

    Full Text Available Context: This paper focuses on providing a functional analysis of smart grids, with the purpose of establishing a framework to identify the main characteristics of the current electric interconnection system in Colombia. It also names the positive incentives proposed by the Colombian government to support both research and development projects that implement non-conventional energy sources and promoting energy management based on efficiency. Method: An architecture model that describes the components interoperability of a smart grid is presented using a descriptive methodology. Results: The results include a list of the objectives established by the Colombian public and private entities related to energy development, specially focusing on the opportunities to provide some kind of artificial intelligence to the current electrical system. Conclusions: It is necessary for the Colombian energy system to supply the energy demand considering electrical safety, social equity, and the minimum environmental impact. These restrictions impose new challenges for the energy system itself: From a technical point of view, the traditional electrical grid must be outfitted with the characteristics of a smart grid, and from a legal perspective, it is essential to generate a clear regulatory framework that promotes the development of this type of technology.

  12. Transcranial Alternating Current Stimulation: A Potential Risk for Genetic Generalized Epilepsy Patients (Study Case)

    Science.gov (United States)

    San-Juan, Daniel; Sarmiento, Carlos Ignacio; Hernandez-Ruiz, Axel; Elizondo-Zepeda, Ernesto; Santos-Vázquez, Gabriel; Reyes-Acevedo, Gerardo; Zúñiga-Gazcón, Héctor; Zamora-Jarquín, Carol Marina

    2016-01-01

    Transcranial alternating current stimulation (tACS) is a re-emergent neuromodulation technique that consists in the external application of oscillating electrical currents that induces changes in cortical excitability. We present the case of a 16-year-old female with pharmaco-resistant juvenile myoclonic epilepsy to 3 antiepileptic’s drugs characterized by 4 myoclonic and 20 absence seizures monthly. She received tACS at 1 mA at 3 Hz pulse train during 60 min over Fp1–Fp2 (10–20 EEG international system position) during 4 consecutive days using an Endeavor™ IOM Systems device® (Natus Medical Incorporated, Middleton, WI, USA). At the 1-month follow-up, she reported a 75% increase in seizures frequency (only myoclonic and tonic–clonic events) and developed a 24-h myoclonic status epilepticus that resolved with oral clonazepam and intravenous valproate. At the 2-month follow-up, the patient reported a 15-day seizure-free period. PMID:27965623

  13. A survey of electron Bernstein wave heating and current drive potential for spherical tokamaks

    Science.gov (United States)

    Urban, Jakub; Decker, Joan; Peysson, Yves; Preinhaelter, Josef; Shevchenko, Vladimir; Taylor, Gary; Vahala, Linda; Vahala, George

    2011-08-01

    The electron Bernstein wave (EBW) is typically the only wave in the electron cyclotron (EC) range that can be applied in spherical tokamaks for heating and current drive (H&CD). Spherical tokamaks (STs) operate generally in high-β regimes, in which the usual EC O- and X-modes are cut off. In this case, EBWs seem to be the only option that can provide features similar to the EC waves—controllable localized H&CD that can be used for core plasma heating as well as for accurate plasma stabilization. The EBW is a quasi-electrostatic wave that can be excited by mode conversion from a suitably launched O- or X-mode; its propagation further inside the plasma is strongly influenced by the plasma parameters. These rather awkward properties make its application somewhat more difficult. In this paper we perform an extensive numerical study of EBW H&CD performance in four typical ST plasmas (NSTX L- and H-mode, MAST Upgrade, NHTX). Coupled ray-tracing (AMR) and Fokker-Planck (LUKE) codes are employed to simulate EBWs of varying frequencies and launch conditions, which are the fundamental EBW parameters that can be chosen and controlled. Our results indicate that an efficient and universal EBW H&CD system is indeed viable. In particular, power can be deposited and current reasonably efficiently driven across the whole plasma radius. Such a system could be controlled by a suitably chosen launching antenna vertical position and would also be sufficiently robust.

  14. Understanding the current status and exploring the potential for distance education in public health in India.

    Science.gov (United States)

    Sharma, Kavya; George, Sunil; Zodpey, Sanjay

    2011-01-01

    Continuing education of health care providers plays an important role in producing a health work force that is efficient and effective. In India public health education has primarily relied on conventional methods of training. However, such methods have limitations in equipping the health workforce of a vast and varied country like India. This paper analyzes the current status of distance education in public health and lists the various courses that are presently available in India through the distance education mode. Presently 25 institutions in India are offering 69 courses in various domains of public health through distance education. The providers of these programs comprised both government and private educational institutions. This paper also points out the role and importance of various stakeholders in the design and delivery of distance education programs in public health and raises key areas that need attention in the governance of such programs. It urges the use of digital technology in the delivery of distance education programs and points out how distance education that is designed and delivered using the latest technology could address the current gap in training human resources for health in India.

  15. Fluid flow in drying drops

    NARCIS (Netherlands)

    Gelderblom, Hanneke

    2013-01-01

    When a suspension drop evaporates, it leaves behind a drying stain. Examples of these drying stains encountered in daily life are coffee or tea stains on a table top, mineral rings on glassware that comes out of the dishwasher, or the salt deposits on the streets in winter. Drying stains are also

  16. Pressure drop in contraction flow

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz

    This note is a supplement to Dynamic of Polymeric Liquids (DPL) page 178. DPL gives an equation for the pressure drop in a tapered (and circular) contraction, valid only at low angles. Here the general definition of contraction flow (the Bagley correction) and a more general method to find...

  17. Solar Energy within the Central Valley, CA: Current Practices and Potential

    Science.gov (United States)

    Hoffacker, M. K.; Hernandez, R. R.; Allen, M. F.

    2015-12-01

    Utility-scale solar energy (USSE, ≥ 1 megawatt [MW]) systems are rapidly being deployed in the Central Valley of California, generating clean electricity and new job opportunities. Utility-scale solar energy systems require substantial quantities of land or space, often prompting an evaluation of environmental impacts and trade-offs when selecting their placement. Utilizing salt-contaminated agricultural land (as the sodium absorption and electrical conductivity values are unsuitably high), unsuitable for food production, and lands within the built environment (developed), can serve as a co-benefit opportunity when reclamation of these lands for USSE development is prioritized. In this study, we quantify the theoretical and generation-based solar energy potential for the Central Valley according to land-cover type, crop type, and for salt-contaminated lands. Further, we utilize the Carnegie Energy and Environmental Compatibility (CEEC) model to identify and prioritize solar energy, integrating environmental resource opportunities and constraints most relevant to the Central Valley. We use the CEEC model to generate a value-based environmental compatibility output for the Central Valley. The Central Valley extends across nearly 60,000 km2 of California with the potential of generating 21,800 - 30,300 TWh y-1 and 41,600 TWh y-1 of solar energy for photovoltaic (PV) and concentrating solar power (CSP), respectively. Pasture, hay, and cultivated crops comprise over half of the Central Valley, much of which is considered prime agriculture or of statewide or local importance for farming (28,200 km2). Together, approximately one-third of this region is salt-contaminated (16%) or developed (11%). This confers a generation-based potential of 5713 - 7891 TWh y-1 and 2770 TWh y-1 for PV and CSP, respectively. As energy, food, and land are inextricably linked, our study shows how land favorable for renewable energy systems can be used more effectively in places where land is

  18. Drop Calibration of Accelerometers for Shock Measurement

    Science.gov (United States)

    2011-08-01

    important that the screen is clear, the records displayed are crisp and values are easily read. The current DSO, used within the Division, in the...Capacitor ≤ ± 0.01% ξc Tolerance of capacitor Drop Mass Reading ≤ ± 0.083 %  dm 0.1g over 120g (typically) Reference Mass Reading ≤ ± 0.1 % rm...Therefore m has uncertainty components due to rm ,  dm and ξrme. The random component is  222 dmrmm  (6.8) and once again  dsodc

  19. A Simple Assay to Screen Antimicrobial Compounds Potentiating the Activity of Current Antibiotics

    Directory of Open Access Journals (Sweden)

    Junaid Iqbal

    2013-01-01

    Full Text Available Antibiotic resistance continues to pose a significant problem in the management of bacterial infections, despite advances in antimicrobial chemotherapy and supportive care. Here, we suggest a simple, inexpensive, and easy-to-perform assay to screen antimicrobial compounds from natural products or synthetic chemical libraries for their potential to work in tandem with the available antibiotics against multiple drug-resistant bacteria. The aqueous extract of Juglans regia tree bark was tested against representative multiple drug-resistant bacteria in the aforementioned assay to determine whether it potentiates the activity of selected antibiotics. The aqueous extract of J. regia bark was added to Mueller-Hinton agar, followed by a lawn of multiple drug-resistant bacteria, Salmonella typhi or enteropathogenic E. coli. Next, filter paper discs impregnated with different classes of antibiotics were placed on the agar surface. Bacteria incubated with extract or antibiotics alone were used as controls. The results showed a significant increase (>30% in the zone of inhibition around the aztreonam, cefuroxime, and ampicillin discs compared with bacteria incubated with the antibiotics/extract alone. In conclusion, our assay is able to detect either synergistic or additive action of J. regia extract against multiple drug-resistant bacteria when tested with a range of antibiotics.

  20. The current and potential impact of genetics and genomics on neuropsychopharmacology.

    Science.gov (United States)

    Harrison, Paul J

    2015-05-01

    One justification for the major scientific and financial investments in genetic and genomic studies in medicine is their therapeutic potential, both for revealing novel targets for drugs which treat the disease process, as well as allowing for more effective and safe use of existing medications. This review considers the extent to which this promise has yet been realised within psychopharmacology, how things are likely to develop in the foreseeable future, and the key issues involved. It draws primarily on examples from schizophrenia and its treatments. One observation is that there is evidence for a range of genetic influences on different aspects of psychopharmacology in terms of discovery science, but far less evidence that meets the standards required before such discoveries impact upon clinical practice. One reason is that results reveal complex genetic influences that are hard to replicate and usually of very small effect. Similarly, the slow progress being made in revealing the genes that underlie the major psychiatric syndromes hampers attempts to apply the findings to identify novel drug targets. Nevertheless, there are some intriguing positive findings of various kinds, and clear potential for genetics and genomics to play an increasing and major role in psychiatric drug discovery. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

  1. Marine phospholipids: The current understanding of their oxidation mechanisms and potential uses for food fortification

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Nielsen, Nina Skall; Baron, Caroline P.

    2017-01-01

    reactions, namely, Strecker aldehydes, pyrroles, oxypolymers, and other impurities that may positively or negatively affect the oxidative stability and quality of marine PL. This review was undertaken to provide the industry and academia with an overview of the current understanding of the quality changes......There is a growing interest in using marine phospholipids (PL) as ingredient for food fortification due to their numerous health benefits. However, the use of marine PL for food fortification is a challenge due to the complex nature of the degradation products that are formed during the handling...... and storage of marine PL. For example, nonenzymatic browning reactions may occur between lipid oxidation products and primary amine group from phosphatidylethanolamine or amino acid residues that are present inmarine PL. Therefore, marine PL contain products from nonenzymatic browning and lipid oxidation...

  2. Potential alternatives to edible oils for biodiesel production - A review of current work

    International Nuclear Information System (INIS)

    Balat, Mustafa

    2011-01-01

    Biodiesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. Currently, biodiesel is mainly prepared from conventionally grown edible oils such as rapeseed, soybean, sunflower and palm thus leading to alleviate food versus fuel issue. About 7% of global vegetable oil supplies were used for biodiesel production in 2007. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. The use of non-edible plant oils when compared with edible oils is very significant in developing countries because of the tremendous demand for edible oils as food, and they are far too expensive to be used as fuel at present. The production of biodiesel from different non-edible oilseed crops has been extensively investigated over the last few years. (author)

  3. In vivo confocal microscopy for the oral cavity: Current state of the field and future potential.

    Science.gov (United States)

    Maher, N G; Collgros, H; Uribe, P; Ch'ng, S; Rajadhyaksha, M; Guitera, P

    2016-03-01

    Confocal microscopy (CM) has been shown to correlate with oral mucosal histopathology in vivo. The purposes of this review are to summarize what we know so far about in vivo CM applications for oral mucosal pathologies, to highlight some current developments with CM devices relevant for oral applications, and to formulate where in vivo CM could hold further application for oral mucosal diagnosis and management. Ovid Medline® and/or Google® searches were performed using the terms 'microscopy, confocal', 'mouth neoplasms', 'mouth mucosa', 'leukoplakia, oral', 'oral lichen planus', 'gingiva', 'cheilitis', 'taste', 'inflammatory oral confocal', 'mucosal confocal' and 'confocal squamous cell oral'. In summary, inclusion criteria were in vivo use of any type of CM for the human oral mucosa and studies on normal or pathological oral mucosa. Experimental studies attempting to identify proteins of interest and microorganisms were excluded. In total 25 relevant articles were found, covering 8 main topics, including normal oral mucosal features (n=15), oral dysplasia or neoplasia (n=7), inflamed oral mucosa (n=3), taste impairment (n=3), oral autoimmune conditions (n=2), pigmented oral pathology/melanoma (n=1), delayed type hypersensitivity (n=1), and cheilitis glandularis (n=1). The evidence for using in vivo CM in these conditions is poor, as it is limited to mainly small descriptive studies. Current device developments for oral CM include improved probe design. The authors propose that future applications for in vivo oral CM may include burning mouth syndrome, intra-operative mapping for cancer surgery, and monitoring and targeted biopsies within field cancerization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Basally activated nonselective cation currents regulate the resting membrane potential in human and monkey colonic smooth muscle

    Science.gov (United States)

    Dwyer, Laura; Rhee, Poong-Lyul; Lowe, Vanessa; Zheng, Haifeng; Peri, Lauren; Ro, Seungil; Sanders, Kenton M.

    2011-01-01

    Resting membrane potential (RMP) plays an important role in determining the basal excitability of gastrointestinal smooth muscle. The RMP in colonic muscles is significantly less negative than the equilibrium potential of K+, suggesting that it is regulated not only by K+ conductances but by inward conductances such as Na+ and/or Ca2+. We investigated the contribution of nonselective cation channels (NSCC) to the RMP in human and monkey colonic smooth muscle cells (SMC) using voltage- and current-clamp techniques. Qualitative reverse transcriptase-polymerase chain reaction was performed to examine potential molecular candidates for these channels among the transient receptor potential (TRP) channel superfamily. Spontaneous transient inward currents and holding currents were recorded in human and monkey SMC. Replacement of extracellular Na+ with equimolar tetraethylammonium or Ca2+ with Mn2+ inhibited basally activated nonselective cation currents. Trivalent cations inhibited these channels. Under current clamp, replacement of extracellular Na+ with N-methyl-d-glucamine or addition of trivalent cations caused hyperpolarization. Three unitary conductances of NSCC were observed in human and monkey colonic SMC. Molecular candidates for basally active NSCC were TRPC1, C3, C4, C7, M2, M4, M6, M7, V1, and V2 in human and monkey SMC. Comparison of the biophysical properties of these TRP channels with basally active NSCC (bINSCC) suggests that TRPM4 and specific TRPC heteromultimer combinations may underlie the three single-channel conductances of bINSCC. In conclusion, these findings suggest that basally activated NSCC contribute to the RMP in human and monkey colonic SMC and therefore may play an important role in determining basal excitability of colonic smooth muscle. PMID:21566016

  5. Current and Potential Developments of Cortisol Aptasensing towards Point-of-Care Diagnostics (POTC

    Directory of Open Access Journals (Sweden)

    Azrul Syafiq Zainol Abidin

    2017-05-01

    Full Text Available Anxiety is a psychological problem that often emerges during the normal course of human life. The detection of anxiety often involves a physical exam and a self-reporting questionnaire. However, these approaches have limitations, as the data might lack reliability and consistency upon application to the same population over time. Furthermore, there might be varying understanding and interpretations of the particular question by the participant, which necessitating the approach of using biomarker-based measurement for stress diagnosis. The most prominent biomarker related to stress, hormone cortisol, plays a key role in the fight-or-flight situation, alters the immune response, and suppresses the digestive and the reproductive systems. We have taken the endeavour to review the available aptamer-based biosensor (aptasensor for cortisol detection. The potential point-of-care diagnostic strategies that could be harnessed for the aptasensing of cortisol were also envisaged.

  6. Shortcomings in the Current Amyotrophic Lateral Sclerosis Trials and Potential Solutions for Improvement

    Directory of Open Access Journals (Sweden)

    Nakul Katyal

    2017-09-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a clinically progressive neurodegenerative syndrome predominantly affecting motor neurons and their associated tracts. Riluzole and edaravone are the only FDA certified drugs for treating ALS. Over the past two decades, almost all clinical trials aiming to develop a successful therapeutic strategy for this disease have failed. Genetic complexity, inadequate animal models, poor clinical trial design, lack of sensitive biomarkers, and diagnostic delays are some of the potential reasons limiting any significant development in ALS clinical trials. In this review, we have outlined the possible reasons for failure of ALS clinical trials, addressed the factors limiting timely diagnosis, and suggested possible solutions for future considerations for each of the shortcomings.

  7. ISTANBUL’S CURRENT STATUS AND POTENTIAL FOR BECOMINGAN INTERNATIONAL FINANCIAL CENTRE

    Directory of Open Access Journals (Sweden)

    Hasmet Sarigul

    2012-07-01

    Full Text Available The Turkish government has been pursuing a goal to turn Istanbul into aregionalcentre for finance and then, an international one.However, creating aninternationalfinancial centre where international demand and supply of fundsmeet is not an easy process. In this context,we aimed toexamine the currentstatus and the potential of Istanbul to become an international financial centre. Inorder to reach the aim of the study, firstly,the characteristics of an internationalfinancial centre have been explained and a brief overview ofthe Turkishgovernment’sofficial plans of development of theinternational financial centrehavebeen given. Then,the strengths, weaknesses, opportunities and threats ofIstanbul havebeen analyzed.Finally,we have made assessments and put forwardsome suggestions.

  8. Proven and potential clinical benefits of washing red blood cells before transfusion: current perspectives

    Directory of Open Access Journals (Sweden)

    Schmidt AE

    2016-08-01

    Full Text Available Amy E Schmidt, Majed A Refaai, Scott A Kirkley, Neil Blumberg Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA Abstract: Red blood cells (RBCs are washed for a variety of reasons such as to remove excess potassium, cytokines, and other allergen proteins from the supernatant and/or to mitigate the effects of the storage lesion. The storage lesion is a product of RBC aging and include leakage of potassium and chloride from the RBCs, depletion of 2,3-diphosphoglycerate and adenosine triphosphate, loss of phospholipids and cholesterol, exposure of phosphatidylserine, elaboration of lipid mediators, loss of glutathione, autoxidation of hemoglobin to methemoglobin contributing to decreased blood flow viscosity and adherence to endothelial cells, increased microparticle formation, and disruption of NO-mediated vasodilation. A storage lesion is thought to be caused in part by oxidative stress, which is characterized by functional and structural changes to the RBCs. The effects of the RBC storage lesion on patient morbidity and mortality have been studied intensively with mixed results. Here, we will summarize the potential benefits of RBC washing. Notably, all patient-based studies on washed RBCs are single-center, small randomized studies or observational data, which await replication and tests of generalizability. Some of the most promising preliminary data suggest that washed transfusions of red cells and platelets reduce mortality in low risk, younger patients with acute myeloid leukemia, mitigate lung injury, and substantially reduce mortality in cardiac surgery. Larger randomized trials to replicate or refute these findings are urgently needed and, most importantly, have the potential to strikingly improve clinical outcomes following transfusion. Keywords: washed blood, transfusion, immunomodulation, red blood cell

  9. Risks from Past, Current, and Potential Hanford Single Shell Tank Leaks

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, Mark B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Watson, David J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wellman, Dawn M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-05-01

    Due to significant delays in constructing and operating the Waste Treatment Plant, which is needed to support retrieval of waste from Hanford’s single shell tanks (SSTs), SSTs may now be required to store tank waste for two to three more decades into the future. Many SSTs were built almost 70 years ago, and all SSTs are well beyond their design lives. Recent examination of monitoring data suggests several of the tanks, which underwent interim stabilization a decade or more ago, may be leaking small amounts (perhaps 150–300 gallons per year) to the subsurface environment. A potential leak from tank T-111 is estimated to have released approximately 2,000 gallons into the subsurface. Observations of past leak events, recently published simulation results, and new simulations all suggest that recent leaks are unlikely to affect underlying groundwater above regulatory limits. However, these recent observations remind us that much larger source terms are still contained in the tanks and are also present in the vadose zone from historical intentional and unintentional releases. Recently there have been significant improvements in methods for detecting and characterizing soil moisture and contaminant releases, understanding and controlling mass-flux, and remediating deep vadose zone and groundwater plumes. To ensure extended safe storage of tank waste in SSTs, the following actions are recommended: 1) Improve capabilities for intrusion and leak detection. 2) Develop defensible conceptual models of intrusion and leak mechanisms. 3) Apply enhanced subsurface characterization methods to improve detection and quantification of moisture changes beneath tanks. 4) Maintain a flux-based assessment of past, present, and potential tank leaks to assess risks and to maintain priorities for applying mitigation actions. 5) Implement and maintain effective mitigation and remediation actions to protect groundwater resources. These actions will enable limited resources to be applied to

  10. Clinical potential of regulatory T cell therapy in liver diseases: An overview and current perspectives

    Directory of Open Access Journals (Sweden)

    Hannah Claire Jeffery

    2016-09-01

    Full Text Available The increasing demand for liver transplantation and the decline in donor organs has highlighted the need for alternative novel therapies to prevent chronic active hepatitis, which eventually leads to liver cirrhosis and liver cancer. Liver histology of chronic hepatitis is composed of both effector and regulatory lymphocytes. The human liver contains different subsets of effector lymphocytes, that are kept in check by a subpopulation of T cells known as Regulatory T cells (Treg. The balance of effector and regulatory lymphocytes generally determines the outcome of hepatic inflammation: resolution, fulminant hepatitis or chronic active hepatitis. Thus, maintaining and adjusting this balance is crucial in immunological manipulation of liver diseases. One of the options to restore this balance is to enrich Treg in the liver disease patients.Advances in the knowledge of Treg biology and development of clinical grade isolation reagents, cell sorting equipment and Good Manufacturing Practice (GMP facilities have paved the way to apply Treg cells as a potential therapy to restore peripheral self-tolerance in autoimmune liver diseases, chronic rejection and post-transplantation. Past and on-going studies have applied Treg in type-1 diabetes mellitus, systemic lupus erythematosus, graft versus host diseases (GVHD and solid organ transplantations. There have not been any new therapies for the autoimmune liver diseases for more than three decades; thus the clinical potential for the application of autologous Treg cell therapy to treat autoimmune liver disease is an attractive and novel option. However, it is fundamental to understand the deep immunology, genetic profiles, biology, homing behavior and microenvironment of Treg before applying the cells to the patients.

  11. Electric generation and ratcheted transport of contact-charged drops

    Science.gov (United States)

    Cartier, Charles A.; Graybill, Jason R.; Bishop, Kyle J. M.

    2017-10-01

    We describe a simple microfluidic system that enables the steady generation and efficient transport of aqueous drops using only a constant voltage input. Drop generation is achieved through an electrohydrodynamic dripping mechanism by which conductive drops grow and detach from a grounded nozzle in response to an electric field. The now-charged drops are transported down a ratcheted channel by contact charge electrophoresis powered by the same voltage input used for drop generation. We investigate how the drop size, generation frequency, and transport velocity depend on system parameters such as the liquid viscosity, interfacial tension, applied voltage, and channel dimensions. The observed trends are well explained by a series of scaling analyses that provide insight into the dominant physical mechanisms underlying drop generation and ratcheted transport. We identify the conditions necessary for achieving reliable operation and discuss the various modes of failure that can arise when these conditions are violated. Our results demonstrate that simple electric inputs can power increasingly complex droplet operations with potential opportunities for inexpensive and portable microfluidic systems.

  12. A Novel Method for Measuring In-Shoe Navicular Drop during Gait

    Directory of Open Access Journals (Sweden)

    Henrik Karstoft

    2012-08-01

    Full Text Available Analysis of foot movement is essential in the treatment and prevention of foot-related disorders. Measuring the in-shoe foot movement during everyday activities, such as sports, has the potential to become an important diagnostic tool in clinical practice. The current paper describes the development of a thin, flexible and robust capacitive strain sensor for the in-shoe measurement of the navicular drop. The navicular drop is a well-recognized measure of foot movement. The position of the strain sensor on the foot was analyzed to determine the optimal points of attachment. The sensor was evaluated against a state-of-the-art video-based system that tracks reflective markers on the bare foot. Preliminary experimental results show that the developed strain sensor is able to measure navicular drop on the bare foot with an accuracy on par with the video-based system and with a high reproducibility. Temporal comparison of video-based, barefoot and in-shoe measurements indicate that the developed sensor measures the navicular drop accurately in shoes and can be used without any discomfort for the user.

  13. Asthma and obesity in children: current evidence and potential systems biology approaches.

    Science.gov (United States)

    Frey, U; Latzin, P; Usemann, J; Maccora, J; Zumsteg, U; Kriemler, S

    2015-01-01

    Both obesity and asthma are highly prevalent, complex diseases modified by multiple factors. Genetic, developmental, lung mechanical, immunological and behavioural factors have all been suggested as playing a causal role between the two entities; however, their complex mechanistic interactions are still poorly understood and evidence of causality in children remains scant. Equally lacking is evidence of effective treatment strategies, despite the fact that imbalances at vulnerable phases in childhood can impact long-term health. This review is targeted at both clinicians frequently faced with the dilemma of how to investigate and treat the obese asthmatic child and researchers interested in the topic. Highlighting the breadth of the spectrum of factors involved, this review collates evidence regarding the investigation and treatment of asthma in obese children, particularly in comparison with current approaches in 'difficult-to-treat' childhood asthma. Finally, the authors propose hypotheses for future research from a systems-based perspective. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Potential of nanotechnology as a delivery platform against tuberculosis: current research review.

    Science.gov (United States)

    Choudhary, S; Kusum Devi, V

    2015-03-28

    This review focusses on the current ongoing research in the field of tuberculosis comprising the resistant strains. It specifies a proper data analysis with results in concise form from areas gripping in: diagnostic nanotechnology, vaccine nanotechnology and the prime field of interest i.e., therapeutic nanotechnology. Primarily, therapeutic area recollects the research findings from advanced drug delivery (primary era) to the targeted drug delivery (modern era). The vaccine-based area derives the immune-specific targeting with enhanced emphasis on vaccine extraction and preparation of nanoparticles. Finally, the diagnostic area signifies the imaging techniques that may be employed in the diagnosis of TB. Not only that, there are some researches that emphasized on finding the comparable diagnostic differences between normal and resistant strains. With the advent of carbon nanotubes, metallic NPs, a newer hope has emerged out in diagnostic research, which may extend to therapeutic research applications too. Modifications of natural polymers, least or no use of organic solvents, size controlled NPs, optimized methodology, etc., are fields that need more effort to bypass toxicity. If above desired possibilities get the priority during research, it may lead to shift in the timeline towards much more oriented research. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Therapeutic Potential of Curcumin in Treatment of Pancreatic Cancer: Current Status and Future Perspectives.

    Science.gov (United States)

    Hosseini, Mina; Hassanian, Seyed Mahdi; Mohammadzadeh, Elham; ShahidSales, Soodabeh; Maftouh, Mina; Fayazbakhsh, Hasan; Khazaei, Majid; Avan, Amir

    2017-07-01

    Pancreatic cancer is among the leading cause of deaths due to cancer with extremely poor prognosis. Gemcitabine is being used in the treatment of patient with pancreatic ductal adenocarcinoma (PDAC), although, the response rate is bellow 12%. A recent phase III trial revealed that FOLFIRINOX could be an option for the treatment of metastatic PDAC patients, although it is associated with increased toxicity. Therefore, identification of novel agents that either improves gemcitabine activity, within novel combinatorial approaches, or with a better efficacy than gemcitabine is warranted. The antitumor activity of curcumin in several tumors, including prostate, breast and colorectal cancers have investigated. A recent phase II trial explored the effects of curcumin in advanced pancreatic cancer patient. They found that oral curcumin was well tolerated. Another trial showed the activity of 8,000 mg of curcumin in combination with gemcitabine in patients with advanced pancreatic cancer. This review summarizes the current knowledge about possible molecular mechanisms of curcumin in PDAC with particular emphasis on preclinical/clinical studies in pancreatic cancer treatment. J. Cell. Biochem. 118: 1634-1638, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  16. NOTES performed using multiple ports of entry: Current experience and potential implications for urologic applications.

    Science.gov (United States)

    Lima, Estevao; Rolanda, Carla; Correia-Pinto, Jorge

    2009-05-01

    An isolated transgastric port raises serious limitations in performing natural orifice translumenal endoscopic surgery (NOTES) complex procedures in the urology field. In an attempt to overcome these limitations, several solutions has been advanced, such as the hybrid approach (adding a single abdominal port access) or the pure NOTES combined approach (joining multiple natural orifice ports). To review the current state of experimental and clinical results of multiple ports in NOTES, a literature search of PubMed was performed, seeking publications from January 2002 to 2008 on NOTES. In addition, we looked at pertinent abstracts of annual meetings of the American Urological Association, the European Association of Urology, and the World Congress of Endourology from 2007. Multiple ports of entry seem to be necessary, mainly for moderately complex procedures. Thus, we could find studies using the hybrid approach (combination of transgastric or transvaginal access with a single transabdominal port), or using the pure NOTES combined approach (transgastric and transvesical, transvaginal and transcolonic, or transgastric and transvaginal). There is still limited experience in humans using these approaches, and no comparative studies exist to date. It is predictable that for moderately complex procedures, we will need multiple ports, so the transvaginal-transabdominal (hybrid) approach is the most appealing, whereas in a pure NOTES perspective, the transgastric-transvesical approach seems to be the preferred approach. We are waiting for new equipment and instruments that are more appropriate for these novel techniques.

  17. SMAD family proteins: the current knowledge on their expression and potential role in neoplastic diseases

    Directory of Open Access Journals (Sweden)

    Magdalena Witkowska

    2014-03-01

    Full Text Available Transforming growth factor beta (TGF-β plays a crucial role and takes part in many processes in the human body both in physiology and pathology. This cytokine is involved in angiogenesis, regulates apoptosis and stimulates divisions of cells, such as hepatocytes, lymphocytes or hematopoietic cells. SMAD proteins family is a unique group of particles responsible for transducting the signal induced by TGF-β into the nucleus. This molecules, after receiving a signal from activated TGF-β, act on transcription factors in the nucleus, leading directly to the expression of the corresponding genes. According to current knowledge, disturbances in the functioning of SMAD proteins are present in a number of diseases. The reduced expression was observed, for example in cardiovascular diseases such as primary pulmonary hypertension or myocardial infarction, autoimmune diseases for instance systemic lupus erythematosus and multiple sclerosis, Alzheimer’s disease or osteoporosis. The latest clinical data showed the presence of mutations in SMAD proteins in cancerogenesis. Mutation of SMAD-4 protein can be detected in half of the patients with pancreatic cancer, 20% of patients with colorectal cancer and 10% of patients with lung cancer. However, mutation in SMAD-2 protein was observed in 7% of both patients with colorectal cancer and lung cancer. On the basis of numerous works, SMAD protein expression would be valuable prognostic factor in some of neoplastic diseases.

  18. How far could the alien boatman Trichocorixa verticalis verticalis spread? Worldwide estimation of its current and future potential distribution.

    Directory of Open Access Journals (Sweden)

    Simone Guareschi

    Full Text Available Invasions of alien species are considered among the least reversible human impacts, with diversified effects on aquatic ecosystems. Since prevention is the most cost-effective way to avoid biodiversity loss and ecosystem problems, one challenge in ecological research is to understand the limits of the fundamental niche of the species in order to estimate how far invasive species could spread. Trichocorixa verticalis verticalis (Tvv is a corixid (Hemiptera originally distributed in North America, but cited as an alien species in three continents. Its impact on native communities is under study, but it is already the dominant species in several saline wetlands and represents a rare example of an aquatic alien insect. This study aims: i to estimate areas with suitable environmental conditions for Tvv at a global scale, thus identifying potential new zones of invasion; and ii to test possible changes in this global potential distribution under a climate change scenario. Potential distributions were estimated by applying a multidimensional envelope procedure based on both climatic data, obtained from observed occurrences, and thermal physiological data. Our results suggest Tvv may expand well beyond its current range and find inhabitable conditions in temperate areas along a wide range of latitudes, with an emphasis on coastal areas of Europe, Northern Africa, Argentina, Uruguay, Australia, New Zealand, Myanmar, India, the western boundary between USA and Canada, and areas of the Arabian Peninsula. When considering a future climatic scenario, the suitability area of Tvv showed only limited changes compared with the current potential distribution. These results allow detection of potential contact zones among currently colonized areas and potential areas of invasion. We also identified zones with a high level of suitability that overlap with areas recognized as global hotspots of biodiversity. Finally, we present hypotheses about possible means of

  19. How Far Could the Alien Boatman Trichocorixa verticalis verticalis Spread? Worldwide Estimation of Its Current and Future Potential Distribution

    Science.gov (United States)

    Guareschi, Simone; Coccia, Cristina; Sánchez-Fernández, David; Carbonell, José Antonio; Velasco, Josefa; Boyero, Luz; Green, Andy J.; Millán, Andrés

    2013-01-01

    Invasions of alien species are considered among the least reversible human impacts, with diversified effects on aquatic ecosystems. Since prevention is the most cost-effective way to avoid biodiversity loss and ecosystem problems, one challenge in ecological research is to understand the limits of the fundamental niche of the species in order to estimate how far invasive species could spread. Trichocorixa verticalis verticalis (Tvv) is a corixid (Hemiptera) originally distributed in North America, but cited as an alien species in three continents. Its impact on native communities is under study, but it is already the dominant species in several saline wetlands and represents a rare example of an aquatic alien insect. This study aims: i) to estimate areas with suitable environmental conditions for Tvv at a global scale, thus identifying potential new zones of invasion; and ii) to test possible changes in this global potential distribution under a climate change scenario. Potential distributions were estimated by applying a multidimensional envelope procedure based on both climatic data, obtained from observed occurrences, and thermal physiological data. Our results suggest Tvv may expand well beyond its current range and find inhabitable conditions in temperate areas along a wide range of latitudes, with an emphasis on coastal areas of Europe, Northern Africa, Argentina, Uruguay, Australia, New Zealand, Myanmar, India, the western boundary between USA and Canada, and areas of the Arabian Peninsula. When considering a future climatic scenario, the suitability area of Tvv showed only limited changes compared with the current potential distribution. These results allow detection of potential contact zones among currently colonized areas and potential areas of invasion. We also identified zones with a high level of suitability that overlap with areas recognized as global hotspots of biodiversity. Finally, we present hypotheses about possible means of spread, focusing on

  20. Pressure drop and arterial compliance - Two arterial parameters in one measurement.

    Science.gov (United States)

    Rotman, Oren M; Zaretsky, Uri; Shitzer, Avraham; Einav, Shmuel

    2017-01-04

    Coronary artery pressure-drop and distensibility (compliance) are two major, seemingly unrelated, parameters in the cardiovascular clinical setting, which are indicative of coronary arteries patency and atherosclerosis severity. While pressure drop is related to flow, and therefore serves as a functional indicator of a stenosis severity, the arterial distensibility is indicative of the arterial stiffness, and hence the arterial wall composition. In the present study, we hypothesized that local pressure drops are dependent on the arterial distensibility, and hence can provide information on both indices. The clinical significance is that a single measurement of pressure drop could potentially provide both functional and bio-mechanical metrics of lesions, and thus assist in real-time decision making prior to stenting. The goal of the current study was to set the basis for understanding this relationship, and define the accuracy and sensitivity required from the pressure measurement system. The investigation was performed using numerical fluid-structure interaction (FSI) simulations, validated experimentally using our high accuracy differential pressure measurement system. Simplified silicone mock coronary arteries with zero to intermediate size stenoses were used, and various combinations of arterial distensibility, diameter, and flow rate were simulated. Results of hyperemic flow cases were also compared to fractional flow reserve (FFR). The results indicate the potential clinical superiority of a high accuracy pressure drop-based parameter over FFR, by: (i) being more lesion-specific, (ii) the possibility to circumvent the FFR dependency on pharmacologically-induced hyperemia, and, (iii) by providing both functional and biomechanical lesion-specific information. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Content knowledge development in a chemistry teacher preparation program: A current potentials and challenges

    Science.gov (United States)

    Widhiyanti, Tuszie; Treagust, David F.; Mocerino, Mauro; Vishnumolakala, Venkat

    2017-08-01

    One of the essential facets in teacher education program is the development of the teachers' content knowledge and it has been suggested by many scholars that the study to analyse the process of content knowledge development in teacher education program is necessary. Regarding this, the aim of this research is to evaluate the existing program of developing pre-service chemistry teachers' content knowledge, especially in the topic about the particulate nature of matter. The curriculum of content knowledge development was analysed using the forms of the curriculum evaluation (Akker, 1998; Goodlad, Klein, and Tye (1979); Treagust, 1987). Within this framework, the curriculum was evaluated in several aspects including the vision and intention of the curriculum as mentioned in the curriculum documents (intended curriculum), the users' interpretation and perception about the curriculum (perceived curriculum), the actual process of curriculum implementation (implemented curriculum), and the outcomes of the curriculum (achieved curriculum). According to the framework used for this study, the research combined qualitative and quantitative methods of data collection and the interpretation including document analysis, classroom observation, interviews, and two-tier diagnostic test. Through this research we examined the coherence among those aspects. The results reveal that although the content knowledge development is explicitly intended in a curriculum, its implementation and lecturers' perceptions give influence in the results as appear in pre-service teachers' achievements. In general, this research provides basic information about the effectiveness of the program including the challenges and the potentials for a reconsideration of the program in the future.

  2. Wavelet applications for modeling in the atmospheric sciences: Current status and potential extensions. Final report

    International Nuclear Information System (INIS)

    Envair, J.H.; Ekstrom, P.

    1995-11-01

    Wavelets are elementary mathematical functions used to construct, transform, and analyze higher functions and observational data. This report describes the results of an exploratory research effort to evaluate wavelet applications for numerically integrating differential equations associated with air pollution transport and conversion models. It is intended to provide a primer on wavelets, and specifically outlines the use of wavelets in a model that addresses derivative-evaluation and boundary-condition problems. Several factors complicate the use of wavelets for integrating differential equations. First, an enormous range of different wavelet types exists, making the choice of wavelet family for a given application challenging. Moreover, in contrast to the Fourier series, the functional derivatives necessary for numerical approximation are difficult to evaluate and consolidate in terms of wavelet expansions, introducing appreciable complexity into any attempt at wavelet-based integration. On the positive side, wavelet techniques do hold promise for effectively interfacing plume and other subgrid-scale phenomena in grid models. Moreover, workable techniques for derivative evaluation and simulation of boundary features appear feasible. Wavelet use may provide a viable, advantageous option for numerically integrating model equations describing fields on all scales of time and distance, especially where inhomogeneous fields exist, and provide a computationally efficient method of focusing on high-variability regions. The potential for wavelets to conduct integrations totally in transform space contrasts with Fourier-based approaches, which essentially preclude such treatments whenever nonlinear chemical processes occur in the modeled system

  3. Regional modeling of large wildfires under current and potential future climates in Colorado and Wyoming, USA

    Science.gov (United States)

    West, Amanda; Kumar, Sunil; Jarnevich, Catherine S.

    2016-01-01

    Regional analysis of large wildfire potential given climate change scenarios is crucial to understanding areas most at risk in the future, yet wildfire models are not often developed and tested at this spatial scale. We fit three historical climate suitability models for large wildfires (i.e. ≥ 400 ha) in Colorado andWyoming using topography and decadal climate averages corresponding to wildfire occurrence at the same temporal scale. The historical models classified points of known large wildfire occurrence with high accuracies. Using a novel approach in wildfire modeling, we applied the historical models to independent climate and wildfire datasets, and the resulting sensitivities were 0.75, 0.81, and 0.83 for Maxent, Generalized Linear, and Multivariate Adaptive Regression Splines, respectively. We projected the historic models into future climate space using data from 15 global circulation models and two representative concentration pathway scenarios. Maps from these geospatial analyses can be used to evaluate the changing spatial distribution of climate suitability of large wildfires in these states. April relative humidity was the most important covariate in all models, providing insight to the climate space of large wildfires in this region. These methods incorporate monthly and seasonal climate averages at a spatial resolution relevant to land management (i.e. 1 km2) and provide a tool that can be modified for other regions of North America, or adapted for other parts of the world.

  4. Epicardial fat and atrial fibrillation: current evidence, potential mechanisms, clinical implications, and future directions.

    Science.gov (United States)

    Wong, Christopher X; Ganesan, Anand N; Selvanayagam, Joseph B

    2017-05-01

    Obesity is increasingly recognized as a major modifiable determinant of atrial fibrillation (AF). Although body mass index and other clinical measures are useful indications of general adiposity, much recent interest has focused on epicardial fat, a distinct adipose tissue depot that can be readily assessed using non-invasive imaging techniques. A growing body of data from epidemiological and clinical studies has demonstrated that epicardial fat is consistently associated with the presence, severity, and recurrence of AF across a range of clinical settings. Evidence from basic science and translational studies has also suggested that arrhythmogenic mechanisms may involve adipocyte infiltration, pro-fibrotic, and pro-inflammatory paracrine effects, oxidative stress, and other pathways. Despite these advances, however, significant uncertainty exists and many questions remain unanswered. In this article, we review our present understanding of epicardial fat, including its classification and quantification, existing evidence implicating its role in AF, potential mechanisms, implications for clinicians, and future directions for research. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  5. Current knowledge on agarolytic enzymes and the industrial potential of agar-derived sugars.

    Science.gov (United States)

    Yun, Eun Ju; Yu, Sora; Kim, Kyoung Heon

    2017-07-01

    Agar is a major cell wall carbohydrate of red macroalgae (Rhodophyta). Sugars derived from agar, such as agarooligosaccharides (AOSs), neoagarooligosaccharides (NAOSs), neoagarobiose (NAB), and 3,6-anhydro-L-galactose (L-AHG), possess various physiological activities. These agar-derived sugars can be produced by hydrolysis using chemicals or agarolytic enzymes. Despite the industrial potential of agar-derived sugars, their application has been hampered mainly due to the absence of efficient processes for the liquefaction and saccharification of agar. In this review, we have focused on strategies for producing high value-added sugars from agarose via chemical or enzymatic liquefaction and enzymatic saccharification. The liquefaction of agarose is a key step for preventing gelling and increasing the solubility of agarose in water by prehydrolyzing agarose into AOSs or NAOSs. For the industrial use of agar-derived sugars, AOS, NAOS, NAB, and L-AHG can be used as functional biomaterials owing to their physiological activities such as antiinflammation, skin whitening, and moisturizing. Recently, it was reported that AHG could be considered as a new anticariogenic sugar to replace xylitol. This review provides a comprehensive overview of processes for the hydrolysis of agar or agarose to produce high value-added sugars and the industrial application of these sugars.

  6. Current treatment of chronic hepatitis C in China: Dilemma and potential problems.

    Science.gov (United States)

    Han, Qun-Ying; Liu, Zheng-Wen

    2016-05-21

    Major advances have been made in the treatment of chronic hepatitis C virus (HCV) infection with the advent of direct-acting antiviral agents (DAAs). China has the most cases of HCV infection worldwide, but none of the DAAs has been approved in mainland China so far, and interferon (IFN)-α-based treatment remains the standard of care. HCV patients without response or with contraindications to IFN-based therapy have no alternative options. However, many patients buy DAAs, especially the generic forms of sofosbuvir, from other countries or areas. Under these circumstances, the use of these drugs may cause many predictable and unpredictable problems in ethics, law and medical practice. Given the obstacles of legal accessibility to DAAs and the potential problems of obtaining and using DAAs in China, the early launching of the DAAs in China or the legalization of buying drugs from areas outside China and using these drugs in China is an urgent issue and needs to be dealt with as soon as possible, in the interest of the patients.

  7. Carbon nanotubes (CNTs) based advanced dermal therapeutics: current trends and future potential.

    Science.gov (United States)

    Kuche, Kaushik; Maheshwari, Rahul; Tambe, Vishakha; Mak, Kit-Kay; Jogi, Hardi; Raval, Nidhi; Pichika, Mallikarjuna Rao; Kumar Tekade, Rakesh

    2018-05-17

    The search for effective and non-invasive delivery modules to transport therapeutic molecules across skin has led to the discovery of a number of nanocarriers (viz.: liposomes, ethosomes, dendrimers, etc.) in the last few decades. However, available literature suggests that these delivery modules face several issues including poor stability, low encapsulation efficiency, and scale-up hurdles. Recently, carbon nanotubes (CNTs) emerged as a versatile tool to deliver therapeutics across skin. Superior stability, high loading capacity, well-developed synthesis protocol as well as ease of scale-up are some of the reason for growing interest in CNTs. CNTs have a unique physical architecture and a large surface area with unique surface chemistry that can be tailored for vivid biomedical applications. CNTs have been thus largely engaged in the development of transdermal systems such as tuneable hydrogels, programmable nonporous membranes, electroresponsive skin modalities, protein channel mimetic platforms, reverse iontophoresis, microneedles, and dermal buckypapers. In addition, CNTs were also employed in the development of RNA interference (RNAi) based therapeutics for correcting defective dermal genes. This review expounds the state-of-art synthesis methodologies, skin penetration mechanism, drug liberation profile, loading potential, characterization techniques, and transdermal applications along with a summary on patent/regulatory status and future scope of CNT based skin therapeutics.

  8. Applying quantitative structure–activity relationship approaches to nanotoxicology: Current status and future potential

    International Nuclear Information System (INIS)

    Winkler, David A.; Mombelli, Enrico; Pietroiusti, Antonio; Tran, Lang; Worth, Andrew; Fadeel, Bengt; McCall, Maxine J.

    2013-01-01

    The potential (eco)toxicological hazard posed by engineered nanoparticles is a major scientific and societal concern since several industrial sectors (e.g. electronics, biomedicine, and cosmetics) are exploiting the innovative properties of nanostructures resulting in their large-scale production. Many consumer products contain nanomaterials and, given their complex life-cycle, it is essential to anticipate their (eco)toxicological properties in a fast and inexpensive way in order to mitigate adverse effects on human health and the environment. In this context, the application of the structure–toxicity paradigm to nanomaterials represents a promising approach. Indeed, according to this paradigm, it is possible to predict toxicological effects induced by chemicals on the basis of their structural similarity with chemicals for which toxicological endpoints have been previously measured. These structure–toxicity relationships can be quantitative or qualitative in nature and they can predict toxicological effects directly from the physicochemical properties of the entities (e.g. nanoparticles) of interest. Therefore, this approach can aid in prioritizing resources in toxicological investigations while reducing the ethical and monetary costs that are related to animal testing. The purpose of this review is to provide a summary of recent key advances in the field of QSAR modelling of nanomaterial toxicity, to identify the major gaps in research required to accelerate the use of quantitative structure–activity relationship (QSAR) methods, and to provide a roadmap for future research needed to achieve QSAR models useful for regulatory purposes

  9. Current and potential impacts of mosquitoes and the pathogens they vector in the Pacific region

    Science.gov (United States)

    LaPointe, Dennis

    2007-01-01

    Mosquitoes and the pathogens they transmit are ubiquitous throughout most of the temperate and tropical regions of the world. The natural and pre-European distribution and diversity of mosquitoes and mosquito-borne diseases throughout much of the Pacific region, however, depicts a depauperate and relatively benign fauna reinforcing the dream of “paradise regained”. In the central and South Pacific few mosquito species were able to colonize the remotest islands and atolls. Native mosquitoes are limited to a few far-ranging species and island endemics are typically restricted to the genera of Aedes and Culex. Only lymphatic filariasis appears to have been present as an endemic mosquito-borne disease before European contact. In nearby Australia, however, some 242 species of mosquitoes are known to occur and more than 70 arboviruses have been identified (Mackenzie 1999). In this regard Australia is more similar to the rest of the tropic and subtropical world than the smaller islands of Oceania. In our ever-shrinking world of global commerce, military activity and travel, the nature of mosquito-borne disease in the Pacific was bound to change. This paper is a brief summary of introduced mosquitoes in the Pacific and their potential impacts on human and wildlife health.

  10. Identifying and acting on potentially inappropriate care? Inadequacy of current hospital coding for this task.

    Science.gov (United States)

    Cooper, P David; Smart, David R

    2017-06-01

    Recent Australian attempts to facilitate disinvestment in healthcare, by identifying instances of 'inappropriate' care from large Government datasets, are subject to significant methodological flaws. Amongst other criticisms has been the fact that the Government datasets utilized for this purpose correlate poorly with datasets collected by relevant professional bodies. Government data derive from official hospital coding, collected retrospectively by clerical personnel, whilst professional body data derive from unit-specific databases, collected contemporaneously with care by clinical personnel. Assessment of accuracy of official hospital coding data for hyperbaric services in a tertiary referral hospital. All official hyperbaric-relevant coding data submitted to the relevant Australian Government agencies by the Royal Hobart Hospital, Tasmania, Australia for financial year 2010-2011 were reviewed and compared against actual hyperbaric unit activity as determined by reference to original source documents. Hospital coding data contained one or more errors in diagnoses and/or procedures in 70% of patients treated with hyperbaric oxygen that year. Multiple discrete error types were identified, including (but not limited to): missing patients; missing treatments; 'additional' treatments; 'additional' patients; incorrect procedure codes and incorrect diagnostic codes. Incidental observations of errors in surgical, anaesthetic and intensive care coding within this cohort suggest that the problems are not restricted to the specialty of hyperbaric medicine alone. Publications from other centres indicate that these problems are not unique to this institution or State. Current Government datasets are irretrievably compromised and not fit for purpose. Attempting to inform the healthcare policy debate by reference to these datasets is inappropriate. Urgent clinical engagement with hospital coding departments is warranted.

  11. Current state of Czech astronomy popularization and its potential for enhancing science career interest

    Science.gov (United States)

    Kříček, Radek

    2015-08-01

    The Czech Republic has a dense net of observatories, astronomical clubs and other activities for both adults and children. Can we use it to improve skills of our pupils and their motivation to choose their career in science? Does the situation in the Czech Republic differ from abroad? What can we improve in the future? These questions were not answered satisfactorily so far. We decided to contribute to solve this issue.We present our survey of current state based mainly on electronic sources and personal dealings. Besides of 56 observatories working with public and many interest clubs, there are other possibilities to meet astronomy. For example, Astronomical Olympiad attracts thousands of pupils across the country each year to solve both theoretical and practical tasks in astronomy. In other projects, children can visit Dark-Sky Parks, design experiments for a stratospheric balloon, observe with CCD or radio devices or build their own rockets.We outline our ongoing project to examine the link between popularization activities and pupils’ or high school students’ attitude toward science and science career. We plan to create a typology of both popularization activities and life stories of people dealing with astronomy. From the methodological point of view, the mixed method design, combining both the qualitative and quantitative approach, will be used to solve the research problems. The basic research plan will be a case study. So far the project is based on interviews with various subjects. We choose people with different life stories, all connected with astronomy or astronomy popularization in some period. We focus on important moments in their career, similarities between subjects, and various types of possible motivation to participate in astronomy-related activities or to study science at university.Future results can be used to help interested organizations such as universities, observatories or astronomical societies. They will be able to work more

  12. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Science.gov (United States)

    Boubela, Roland N.; Kalcher, Klaudius; Nasel, Christian; Moser, Ewald

    2014-02-01

    Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TRstudied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  13. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    Directory of Open Access Journals (Sweden)

    Roland N Boubela

    2014-02-01

    Full Text Available Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to true neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TR< 0.5s scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.. From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  14. A Critical Assessment of the Resource Depletion Potential of Current and Future Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jens F. Peters

    2016-12-01

    Full Text Available Resource depletion aspects are repeatedly used as an argument for a shift towards new battery technologies. However, whether serious shortages due to the increased demand for traction and stationary batteries can actually be expected is subject to an ongoing discussion. In order to identify the principal drivers of resource depletion for battery production, we assess different lithium-ion battery types and a new lithium-free battery technology (sodium-ion under this aspect, applying different assessment methodologies. The findings show that very different results are obtained with existing impact assessment methodologies, which hinders clear interpretation. While cobalt, nickel and copper can generally be considered as critical metals, the magnitude of their depletion impacts in comparison with that of other battery materials like lithium, aluminum or manganese differs substantially. A high importance is also found for indirect resource depletion effects caused by the co-extraction of metals from mixed ores. Remarkably, the resource depletion potential per kg of produced battery is driven only partially by the electrode materials and thus depends comparably little on the battery chemistry itself. One of the key drivers for resource depletion seems to be the metals (and co-products in electronic parts required for the battery management system, a component rather independent from the actual battery chemistry. However, when assessing the batteries on a capacity basis (per kWh storage capacity, a high-energy density also turns out to be relevant, since it reduces the mass of battery required for providing one kWh, and thus the associated resource depletion impacts.

  15. Tank-connected food waste disposer systems--current status and potential improvements.

    Science.gov (United States)

    Bernstad, A; Davidsson, A; Tsai, J; Persson, E; Bissmont, M; la Cour Jansen, J

    2013-01-01

    An unconventional system for separate collection of food waste was investigated through evaluation of three full-scale systems in the city of Malmö, Sweden. Ground food waste is led to a separate settling tank where food waste sludge is collected regularly with a tank-vehicle. These tank-connected systems can be seen as a promising method for separate collection of food waste from both households and restaurants. Ground food waste collected from these systems is rich in fat and has a high methane potential when compared to food waste collected in conventional bag systems. The content of heavy metals is low. The concentrations of N-tot and P-tot in sludge collected from sedimentation tanks were on average 46.2 and 3.9 g/kg TS, equalling an estimated 0.48 and 0.05 kg N-tot and P-tot respectively per year and household connected to the food waste disposer system. Detergents in low concentrations can result in increased degradation rates and biogas production, while higher concentrations can result in temporary inhibition of methane production. Concentrations of COD and fat in effluent from full-scale tanks reached an average of 1068 mg/l and 149 mg/l respectively over the five month long evaluation period. Hydrolysis of the ground material is initiated between sludge collection occasions (30 days). Older food waste sludge increases the degradation rate and the risks of fugitive emissions of methane from tanks between collection occasions. Increased particle size decreases hydrolysis rate and could thus decrease losses of carbon and nutrients in the sewerage system, but further studies in full-scale systems are needed to confirm this. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Mapping Current and Potential Distribution of Non-Native Prosopis juliflora in the Afar Region of Ethiopia

    OpenAIRE

    Wakie, Tewodros T.; Evangelista, Paul H.; Jarnevich, Catherine S.; Laituri, Melinda

    2014-01-01

    We used correlative models with species occurrence points, Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation indices, and topo-climatic predictors to map the current distribution and potential habitat of invasive Prosopis juliflora in Afar, Ethiopia. Time-series of MODIS Enhanced Vegetation Indices (EVI) and Normalized Difference Vegetation Indices (NDVI) with 250 m2 spatial resolution were selected as remote sensing predictors for mapping distributions, while WorldClim bioclim...

  17. Potential of low-temperature anaerobic digestion to address current environmental concerns on swine production.

    Science.gov (United States)

    Massé, D I; Masse, L; Xia, Y; Gilbert, Y

    2010-04-01

    Environmental issues associated with swine production are becoming a major concern among the general public and are thus an important challenge for the swine industry. There is now a renewed interest in environmental biotechnologies that can minimize the impact of swine production and add value to livestock by-products. An anaerobic biotechnology called psychrophilic anaerobic digestion (PAD) in sequencing batch reactors (SBR) has been developed at Agriculture and Agri-Food Canada. This very stable biotechnology recovers usable energy, stabilizes and deodorizes manure, and increases the availability of plant nutrients. Experimental results indicated that PAD of swine manure slurry at 15 to 25 degrees C in intermittently fed SBR reduces the pollution potential of manure by removing up to 90% of the soluble chemical oxygen demand. The process performs well under intermittent feeding, once to 3 times a week, and without external mixing. Bioreactor feeding activities can thus be easily integrated into the routine manure removal procedures in the barn, with minimal interference with other farm operations and use of existing manure-handling equipment. Process stability was not affected by the presence of antibiotics in manure. The PAD process was efficient in eliminating populations of zoonotic pathogens and parasites present in raw livestock manure slurries. Psychrophilic anaerobic digestion in SBR could also be used for swine mortality disposal. The addition of swine carcasses, at loading rates representing up to 8 times the normal mortality rates on commercial farms, did not affect the stability of SBR. No operational problems were related to the formation of foam and scum. The biotechnology was successfully operated at semi-industrial and full commercial scales. Biogas production rate exceeded 0.20 L of methane per gram of total chemical oxygen demand fed to the SBR. The biogas was of excellent quality, with a methane concentration ranging from 70 to 80%. The

  18. Action Potential Broadening in Capsaicin-Sensitive DRG Neurons from Frequency-Dependent Reduction of Kv3 Current.

    Science.gov (United States)

    Liu, Pin W; Blair, Nathaniel T; Bean, Bruce P

    2017-10-04

    Action potential (AP) shape is a key determinant of cellular electrophysiological behavior. We found that in small-diameter, capsaicin-sensitive dorsal root ganglia neurons corresponding to nociceptors (from rats of either sex), stimulation at frequencies as low as 1 Hz produced progressive broadening of the APs. Stimulation at 10 Hz for 3 s resulted in an increase in AP width by an average of 76 ± 7% at 22°C and by 38 ± 3% at 35°C. AP clamp experiments showed that spike broadening results from frequency-dependent reduction of potassium current during spike repolarization. The major current responsible for frequency-dependent reduction of overall spike-repolarizing potassium current was identified as Kv3 current by its sensitivity to low concentrations of 4-aminopyridine (IC 50 action potentials of small-diameter rat DRG neurons showed spike broadening at frequencies as low as 1 Hz and that spike broadening resulted predominantly from frequency-dependent inactivation of Kv3 channels. Spike width helps to control transmitter release, conduction velocity, and firing patterns and understanding the role of particular potassium channels can help to guide new pharmacological strategies for targeting pain-sensing neurons selectively. Copyright © 2017 the authors 0270-6474/17/379705-10$15.00/0.

  19. From nuclei to liquid drops

    Energy Technology Data Exchange (ETDEWEB)

    Menchaca-Rocha, A.; Huidobro, F.; Michaelian, K.; Perez, A.; Rodriguez, V. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Fisica; Carjan, N. [Bordeaux-1 Univ., 33 - Gradignan (France). Centre d`Etudes Nucleaires

    1995-12-31

    Collisions of symmetric mercury-drop pairs have been studied experimentally as a function of impact parameter, in a relative-velocity range going from a coalescence-dominated region to interactions yielding several residues. The experiments are compared with predictions of a dynamical model used in nuclear physics. The time evolution of the shapes is well reproduced by the simulation. (authors). 8 refs., 3 figs.

  20. The dynamics of Leidenfrost drops

    OpenAIRE

    van Limbeek, Michiel Antonius Jacobus

    2017-01-01

    Temperature control is omnipresent in today’s life: from keeping your fridge cold, maintaining a room at a pleasant temperature or preventing your computer from overheating. Efficient ways of heat transfer are often based on phase change, making use of the high latent heat of evaporation. In the context of spray cooling, liquid drops are impacting a hot plate to ensure a rapid cooling. At some temperature however, no contact occurs between the liquid and the plate, and the heat transfer rate ...

  1. Liquid drops attract or repel by the inverted Cheerios effect.

    Science.gov (United States)

    Karpitschka, Stefan; Pandey, Anupam; Lubbers, Luuk A; Weijs, Joost H; Botto, Lorenzo; Das, Siddhartha; Andreotti, Bruno; Snoeijer, Jacco H

    2016-07-05

    Solid particles floating at a liquid interface exhibit a long-ranged attraction mediated by surface tension. In the absence of bulk elasticity, this is the dominant lateral interaction of mechanical origin. Here, we show that an analogous long-range interaction occurs between adjacent droplets on solid substrates, which crucially relies on a combination of capillarity and bulk elasticity. We experimentally observe the interaction between droplets on soft gels and provide a theoretical framework that quantitatively predicts the interaction force between the droplets. Remarkably, we find that, although on thick substrates the interaction is purely attractive and leads to drop-drop coalescence, for relatively thin substrates a short-range repulsion occurs, which prevents the two drops from coming into direct contact. This versatile interaction is the liquid-on-solid analog of the "Cheerios effect." The effect will strongly influence the condensation and coarsening of drops on soft polymer films, and has potential implications for colloidal assembly and mechanobiology.

  2. Electrostatic charging and levitation of helium II drops

    International Nuclear Information System (INIS)

    Niemela, J.J.

    1997-01-01

    Liquid Helium II drops, of diameter 1 mm or less, are charged with positive helium ions and subsequently levitated by static electric fields. Stable levitation was achieved for drops of order 100-150 micrometers in diameter. The suspended drops could be translated to arbitrary positions within the levitator using additional superimposed DC electric fields, and also could be made to oscillate stably about their average positions by means of an applied time-varying electric field. A weak corona discharge was used to produce the necessary ions for levitation. A novel superfluid film flow device, developed for the controlled deployment of large charged drops, is described. Also discussed is an adjustable electric fountain that requires only a field emission tip operating at modest potentials, and works in both Helium I and Helium II

  3. Dropped fuel damage prediction techniques and the DROPFU code

    International Nuclear Information System (INIS)

    Mottershead, K.J.; Beardsmore, D.W.; Money, G.

    1995-01-01

    During refuelling, and fuel handling, at UK Advanced Gas Cooled Reactor (AGR) stations it is recognised that the accidental dropping of fuel is a possibility. This can result in dropping individual fuel elements, a complete fuel stringer, or a whole assembly. The techniques for assessing potential damage have been developed over a number of years. This paper describes how damage prediction techniques have subsequently evolved to meet changing needs. These have been due to later fuel designs and the need to consider drops in facilities outside the reactor. The paper begins by briefly describing AGR fuel and possible dropped fuel scenarios. This is followed by a brief summary of the damage mechanisms and the assessment procedure as it was first developed. The paper then describes the additional test work carried out, followed by the detailed numerical modelling. Finally, the paper describes the extensions to the practical assessment methods. (author)

  4. Estimation of the potential efficiency of a multijunction solar cell at a limit balance of photogenerated currents

    Energy Technology Data Exchange (ETDEWEB)

    Mintairov, M. A., E-mail: mamint@mail.ioffe.ru; Evstropov, V. V.; Mintairov, S. A.; Shvarts, M. Z.; Timoshina, N. Kh.; Kalyuzhnyy, N. A. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2015-05-15

    A method is proposed for estimating the potential efficiency which can be achieved in an initially unbalanced multijunction solar cell by the mutual convergence of photogenerated currents: to extract this current from a relatively narrow band-gap cell and to add it to a relatively wide-gap cell. It is already known that the properties facilitating relative convergence are inherent to such objects as bound excitons, quantum dots, donor-acceptor pairs, and others located in relatively wide-gap cells. In fact, the proposed method is reduced to the problem of obtaining such a required light current-voltage (I–V) characteristic which corresponds to the equality of all photogenerated short-circuit currents. Two methods for obtaining the required light I–V characteristic are used. The first one is selection of the spectral composition of the radiation incident on the multijunction solar cell from an illuminator. The second method is a double shift of the dark I–V characteristic: a current shift J{sub g} (common set photogenerated current) and a voltage shift (−J{sub g}R{sub s}), where R{sub s} is the series resistance. For the light and dark I–V characteristics, a general analytical expression is derived, which considers the effect of so-called luminescence coupling in multijunction solar cells. The experimental I–V characteristics are compared with the calculated ones for a three-junction InGaP/GaAs/Ge solar cell with R{sub s} = 0.019 Ω cm{sup 2} and a maximum factual efficiency of 36.9%. Its maximum potential efficiency is estimated as 41.2%.

  5. Device for making liquid drops

    International Nuclear Information System (INIS)

    Yamada, Masao; Fukuda, Fumito; Nishikawa, Masana; Ishii, Takeshi.

    1976-01-01

    Object: To provide a device for producing liquid drops in the form of liquefied gases indispensable to make deuterium and tritium ice pellets used as a fusion fuel in a tokamak type fusion reactor. Structure: First, pressure P 1 at the upper surface of liquefied gas in a container and outlet pressure P 2 of a nozzle disposed at the lower part of the container are adjusted into the state of P 1 >= P 2 , and it is preset so that even under such conditions, the liquefied gas from the nozzle is not naturally flown out. Next, a vibration plate disposed within the container is rapidly downwardly advanced toward the nozzle through a predetermined distance. As a result, pressure of the liquefied gas within a depression under the vibration plate rises instantaneously or in a pulse fashion to dissatisfy the aforesaid set condition whereby the liquefied gas may be flown out from the nozzle in the form of liquid drops. In accordance with the present device, it is possible to produce a suitable number of drops at a suitable point. (Yoshihara, H.)

  6. Electrode breakdown potentials in MHD plasmas

    International Nuclear Information System (INIS)

    Sodha, M.S.; Raju, G.V.R.; Kumar, A.S.; Gupta, Bhumesh

    1988-01-01

    Electrode breakdown potentials and current densities have been calculated for both the thermionically electron emitting and non-emitting cathodes. Calculated values have been compared with the available experimental results. It is found that the cathode potential drop for the breakdown is almost unaffected by the emission. However, both the total potential difference between the anode and the cathode and the current density at the breakdown are higher for electron-emitting cathodes than for non-emitting cathodes. (author)

  7. A computational model of the ionic currents, Ca2+ dynamics and action potentials underlying contraction of isolated uterine smooth muscle.

    Directory of Open Access Journals (Sweden)

    Wing-Chiu Tong

    2011-04-01

    Full Text Available Uterine contractions during labor are discretely regulated by rhythmic action potentials (AP of varying duration and form that serve to determine calcium-dependent force production. We have employed a computational biology approach to develop a fuller understanding of the complexity of excitation-contraction (E-C coupling of uterine smooth muscle cells (USMC. Our overall aim is to establish a mathematical platform of sufficient biophysical detail to quantitatively describe known uterine E-C coupling parameters and thereby inform future empirical investigations of physiological and pathophysiological mechanisms governing normal and dysfunctional labors. From published and unpublished data we construct mathematical models for fourteen ionic currents of USMCs: Ca2+ currents (L- and T-type, Na+ current, an hyperpolarization-activated current, three voltage-gated K+ currents, two Ca2+-activated K+ current, Ca2+-activated Cl current, non-specific cation current, Na+-Ca2+ exchanger, Na+-K+ pump and background current. The magnitudes and kinetics of each current system in a spindle shaped single cell with a specified surface area:volume ratio is described by differential equations, in terms of maximal conductances, electrochemical gradient, voltage-dependent activation/inactivation gating variables and temporal changes in intracellular Ca2+ computed from known Ca2+ fluxes. These quantifications are validated by the reconstruction of the individual experimental ionic currents obtained under voltage-clamp. Phasic contraction is modeled in relation to the time constant of changing [Ca2+]i. This integrated model is validated by its reconstruction of the different USMC AP configurations (spikes, plateau and bursts of spikes, the change from bursting to plateau type AP produced by estradiol and of simultaneous experimental recordings of spontaneous AP, [Ca2+]i and phasic force. In summary, our advanced mathematical model provides a powerful tool to

  8. Testing the price and affordability of healthy and current (unhealthy) diets and the potential impacts of policy change in Australia.

    Science.gov (United States)

    Lee, Amanda J; Kane, Sarah; Ramsey, Rebecca; Good, Elizabeth; Dick, Mathew

    2016-04-12

    Price and affordability of foods are important determinants of health. Targeted food pricing policies may help improve population diets. However, methods producing comparable data to inform relevant policy decisions are lacking in Australia and globally. The objective was to develop and pilot standardised methods to assess the price, relative price and affordability of healthy (recommended) and current (unhealthy) diets and test impacts of a potential policy change. Methods followed the optimal approach proposed by INFORMAS using recent Australian dietary intake data and guidelines. Draft healthy and current (unhealthy) diet baskets were developed for five household structures. Food prices were collected in stores in a high and low SES location in Brisbane, Australia. Diet prices were calculated and compared with household incomes, and with potential changes to the Australian Taxation System. Wilcoxen-signed rank tests were used to compare differences in price. The draft tools and protocols were deemed acceptable at household level, but methods could be refined. All households spend more on current (unhealthy) diets than required to purchase healthy (recommended) diets, with the majority (53-64 %) of the food budget being spent on 'discretionary' choices, including take-away foods and alcohol. A healthy diet presently costs between 20-31 % of disposable income of low income households, but would become unaffordable for these families under proposed changes to expand the GST to apply to all foods in Australia. Results confirmed that diet pricing methods providing meaningful, comparable data to inform potential fiscal and health policy actions can be developed, but draft tools should be refined. Results suggest that healthy diets can be more affordable than current (unhealthy) diets in Australia, but other factors may be as important as price in determining food choices.

  9. Testing the price and affordability of healthy and current (unhealthy diets and the potential impacts of policy change in Australia

    Directory of Open Access Journals (Sweden)

    Amanda J. Lee

    2016-04-01

    Full Text Available Abstract Background Price and affordability of foods are important determinants of health. Targeted food pricing policies may help improve population diets. However, methods producing comparable data to inform relevant policy decisions are lacking in Australia and globally. The objective was to develop and pilot standardised methods to assess the price, relative price and affordability of healthy (recommended and current (unhealthy diets and test impacts of a potential policy change. Methods Methods followed the optimal approach proposed by INFORMAS using recent Australian dietary intake data and guidelines. Draft healthy and current (unhealthy diet baskets were developed for five household structures. Food prices were collected in stores in a high and low SES location in Brisbane, Australia. Diet prices were calculated and compared with household incomes, and with potential changes to the Australian Taxation System. Wilcoxen-signed rank tests were used to compare differences in price. Results The draft tools and protocols were deemed acceptable at household level, but methods could be refined. All households spend more on current (unhealthy diets than required to purchase healthy (recommended diets, with the majority (53–64 % of the food budget being spent on ‘discretionary’ choices, including take-away foods and alcohol. A healthy diet presently costs between 20–31 % of disposable income of low income households, but would become unaffordable for these families under proposed changes to expand the GST to apply to all foods in Australia. Conclusions Results confirmed that diet pricing methods providing meaningful, comparable data to inform potential fiscal and health policy actions can be developed, but draft tools should be refined. Results suggest that healthy diets can be more affordable than current (unhealthy diets in Australia, but other factors may be as important as price in determining food choices.

  10. Mapping current and potential distribution of non-native Prosopis juliflora in the Afar region of Ethiopia.

    Directory of Open Access Journals (Sweden)

    Tewodros T Wakie

    Full Text Available We used correlative models with species occurrence points, Moderate Resolution Imaging Spectroradiometer (MODIS vegetation indices, and topo-climatic predictors to map the current distribution and potential habitat of invasive Prosopis juliflora in Afar, Ethiopia. Time-series of MODIS Enhanced Vegetation Indices (EVI and Normalized Difference Vegetation Indices (NDVI with 250 m2 spatial resolution were selected as remote sensing predictors for mapping distributions, while WorldClim bioclimatic products and generated topographic variables from the Shuttle Radar Topography Mission product (SRTM were used to predict potential infestations. We ran Maxent models using non-correlated variables and the 143 species- occurrence points. Maxent generated probability surfaces were converted into binary maps using the 10-percentile logistic threshold values. Performances of models were evaluated using area under the receiver-operating characteristic (ROC curve (AUC. Our results indicate that the extent of P. juliflora invasion is approximately 3,605 km2 in the Afar region (AUC  = 0.94, while the potential habitat for future infestations is 5,024 km2 (AUC  = 0.95. Our analyses demonstrate that time-series of MODIS vegetation indices and species occurrence points can be used with Maxent modeling software to map the current distribution of P. juliflora, while topo-climatic variables are good predictors of potential habitat in Ethiopia. Our results can quantify current and future infestations, and inform management and policy decisions for containing P. juliflora. Our methods can also be replicated for managing invasive species in other East African countries.

  11. Mapping current and potential distribution of non-native Prosopis juliflora in the Afar region of Ethiopia.

    Science.gov (United States)

    Wakie, Tewodros T; Evangelista, Paul H; Jarnevich, Catherine S; Laituri, Melinda

    2014-01-01

    We used correlative models with species occurrence points, Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation indices, and topo-climatic predictors to map the current distribution and potential habitat of invasive Prosopis juliflora in Afar, Ethiopia. Time-series of MODIS Enhanced Vegetation Indices (EVI) and Normalized Difference Vegetation Indices (NDVI) with 250 m2 spatial resolution were selected as remote sensing predictors for mapping distributions, while WorldClim bioclimatic products and generated topographic variables from the Shuttle Radar Topography Mission product (SRTM) were used to predict potential infestations. We ran Maxent models using non-correlated variables and the 143 species- occurrence points. Maxent generated probability surfaces were converted into binary maps using the 10-percentile logistic threshold values. Performances of models were evaluated using area under the receiver-operating characteristic (ROC) curve (AUC). Our results indicate that the extent of P. juliflora invasion is approximately 3,605 km2 in the Afar region (AUC  = 0.94), while the potential habitat for future infestations is 5,024 km2 (AUC  = 0.95). Our analyses demonstrate that time-series of MODIS vegetation indices and species occurrence points can be used with Maxent modeling software to map the current distribution of P. juliflora, while topo-climatic variables are good predictors of potential habitat in Ethiopia. Our results can quantify current and future infestations, and inform management and policy decisions for containing P. juliflora. Our methods can also be replicated for managing invasive species in other East African countries.

  12. Electrostatic interaction between Interball-2 and the ambient plasma. 1. Determination of the spacecraft potential from current calculations

    Directory of Open Access Journals (Sweden)

    M. Bouhram

    2002-03-01

    Full Text Available The Interball-2 spacecraft travels at altitudes extending up to 20 000 km, and becomes positively charged due to the low-plasma densities encountered and the photoemission on its sunlit surface. Therefore, a knowledge of the spacecraft potential Fs is required for correcting accurately thermal ion measurements on Interball-2. The determination of Fs  is based on the balance of currents between escaping photoelectrons and incoming plasma electrons. A three-dimensional model of the potential structure surrounding Interball-2, including a realistic geometry and neglecting the space-charge densities, is used to find, through particle simulations, current-voltage relations of impacting plasma electrons Ie (Fs and escaping photoelectrons Iph (Fs . The inferred relations are compared to analytic relationships in order to quantify the effects of the spacecraft geometry, the ambient magnetic field B0 and the electron temperature Te . We found that the complex geometry has a weak effect on the inferred currents, while the presence of B0 tends to decrease their values. Providing that the photoemission saturation current density Jph0 is known, a relation between Fs and the plasma density Ne can be derived by using the current balance. Since Jph0 is critical to this process, simultaneous measurements of Ne from Z-mode observations in the plasmapause, and data on the potential difference Fs  - Fp  between the spacecraft and an electric probe (p are used in order to reverse the process. A value Jph0 ~ = 32 µAm-2 is estimated, close to laboratory tests, but less than typical measurements in space. Using this value, Ne and Fs  can be derived systematically from electric field measurements without any additional calculation. These values are needed for correcting the distributions of low-energy ions measured by the Hyperboloid experiment on Interball-2. The effects of the potential structure on ion trajectories reaching Hyperboloid are discussed

  13. Toward Production From Gas Hydrates: Current Status, Assessment of Resources, and Simulation-Based Evaluationof Technology and Potential

    Energy Technology Data Exchange (ETDEWEB)

    Reagan, Matthew; Moridis, George J.; Collett, Timothy; Boswell, Ray; Kurihara, M.; Reagan, Matthew T.; Koh, Carolyn; Sloan, E. Dendy

    2008-02-12

    Gas hydrates are a vast energy resource with global distribution in the permafrost and in the oceans. Even if conservative estimates are considered and only a small fraction is recoverable, the sheer size of the resource is so large that it demands evaluation as a potential energy source. In this review paper, we discuss the distribution of natural gas hydrate accumulations, the status of the primary international R&D programs, and the remaining science and technological challenges facing commercialization of production. After a brief examination of gas hydrate accumulations that are well characterized and appear to be models for future development and gas production, we analyze the role of numerical simulation in the assessment of the hydrate production potential, identify the data needs for reliable predictions, evaluate the status of knowledge with regard to these needs, discuss knowledge gaps and their impact, and reach the conclusion that the numerical simulation capabilities are quite advanced and that the related gaps are either not significant or are being addressed. We review the current body of literature relevant to potential productivity from different types of gas hydrate deposits, and determine that there are consistent indications of a large production potential at high rates over long periods from a wide variety of hydrate deposits. Finally, we identify (a) features, conditions, geology and techniques that are desirable in potential production targets, (b) methods to maximize production, and (c) some of the conditions and characteristics that render certain gas hydrate deposits undesirable for production.

  14. Load drop evaluation for TWRS FSAR

    Energy Technology Data Exchange (ETDEWEB)

    Julyk, L.J.; Ralston, G.L.

    1996-09-30

    Operational or remediation activities associated with existing underground high-level waste storage tank structures at the Hanford Site often require the installation/removal of various equipment items. To gain tank access for installation or removal of this equipment, large concrete cover blocks must be removed and reinstalled in existing concrete pits above the tanks. An accidental drop of the equipment or cover blocks while being moved over the tanks that results in the release of contaminants to the air poses a potential risk to onsite workers or to the offsite public. To minimize this potential risk, the use of critical lift hoisting and rigging procedures and restrictions on lift height are being considered during development of the new tank farm Basis for Interim Operation and Final Safety Analysis Report. The analysis contained herein provides information for selecting the appropriate lift height restrictions for these activities.

  15. Vortex flow in acoustically levitated drops

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.L.; Xie, W.J. [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China); Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2011-08-29

    The internal flow of acoustically levitated water drops is investigated experimentally. This study reveals a kind of vortex flow which rotates in the meridional plane of the levitated drop. The magnitude of fluid velocity is nearly vanishing at the drop center, whereas it increases toward the free surface of a levitated drop until the maximum value of about 80 mm/s. A transition of streamline shapes from concentric circles to ellipses takes place at the distance of about 1.2 mm from the drop center. The fluid velocity distribution is plotted as a function of polar angle for seven characteristic streamlines. -- Highlights: → We experimentally observe the internal flow of acoustically levitated water drops. → We present a fascinating structure of vortex flow inside the levitated water drop. → This vortex flow rotates around the drop center in the meridional plane. → Velocity distribution information of this vortex flow is quantitatively analyzed.

  16. Vortex flow in acoustically levitated drops

    International Nuclear Information System (INIS)

    Yan, Z.L.; Xie, W.J.; Wei, B.

    2011-01-01

    The internal flow of acoustically levitated water drops is investigated experimentally. This study reveals a kind of vortex flow which rotates in the meridional plane of the levitated drop. The magnitude of fluid velocity is nearly vanishing at the drop center, whereas it increases toward the free surface of a levitated drop until the maximum value of about 80 mm/s. A transition of streamline shapes from concentric circles to ellipses takes place at the distance of about 1.2 mm from the drop center. The fluid velocity distribution is plotted as a function of polar angle for seven characteristic streamlines. -- Highlights: → We experimentally observe the internal flow of acoustically levitated water drops. → We present a fascinating structure of vortex flow inside the levitated water drop. → This vortex flow rotates around the drop center in the meridional plane. → Velocity distribution information of this vortex flow is quantitatively analyzed.

  17. Nectar and pollination drops: how different are they?

    Science.gov (United States)

    Nepi, Massimo; von Aderkas, Patrick; Wagner, Rebecca; Mugnaini, Serena; Coulter, Andrea; Pacini, Ettore

    2009-08-01

    Pollination drops and nectars (floral nectars) are secretions related to plant reproduction. The pollination drop is the landing site for the majority of gymnosperm pollen, whereas nectar of angiosperm flowers represents a common nutritional resource for a large variety of pollinators. Extrafloral nectars also are known from all vascular plants, although among the gymnosperms they are restricted to the Gnetales. Extrafloral nectars are not generally involved in reproduction but serve as 'reward' for ants defending plants against herbivores (indirect defence). Although very different in their task, nectars and pollination drops share some features, e.g. basic chemical composition and eventual consumption by animals. This has led some authors to call these secretions collectively nectar. Modern techniques that permit chemical analysis and protein characterization have very recently added important information about these sugary secretions that appear to be much more than a 'reward' for pollinating (floral nectar) and defending animals (extrafloral nectar) or a landing site for pollen (pollination drop). Nectar and pollination drops contain sugars as the main components, but the total concentration and the relative proportions are different. They also contain amino acids, of which proline is frequently the most abundant. Proteomic studies have revealed the presence of common functional classes of proteins such as invertases and defence-related proteins in nectar (floral and extrafloral) and pollination drops. Invertases allow for dynamic rearrangement of sugar composition following secretion. Defence-related proteins provide protection from invasion by fungi and bacteria. Currently, only few species have been studied in any depth. The chemical composition of the pollination drop must be investigated in a larger number of species if eventual phylogenetic relationships are to be revealed. Much more information can be provided from further proteomic studies of both

  18. Drag and drop display & builder

    Energy Technology Data Exchange (ETDEWEB)

    Bolshakov, Timofei B.; Petrov, Andrey D.; /Fermilab

    2007-12-01

    The Drag and Drop (DnD) Display & Builder is a component-oriented system that allows users to create visual representations of data received from data acquisition systems. It is an upgrade of a Synoptic Display mechanism used at Fermilab since 2002. Components can be graphically arranged and logically interconnected in the web-startable Project Builder. Projects can be either lightweight AJAX- and SVG-based web pages, or they can be started as Java applications. The new version was initiated as a response to discussions between the LHC Controls Group and Fermilab.

  19. The Persistence of Prior Concepts about Electric Potential, Current Intensity and Ohm’s Law in Students of Engineering

    Directory of Open Access Journals (Sweden)

    María Cristina Periago

    2005-11-01

    Full Text Available The aim of this research was to evaluate and analyze second-year industrial-engineering and chemical-engineering students’ prior knowledge of conceptual aspects of circuit theory. Specifically, we have focused on the basic concepts of electric potential and current intensity and on the fundamental relationship between these as expressed by Ohm’s Law. In order to find out what the students’ prior concepts were, we applied a survey containing nine questions dealing with the most basic concepts of circuit theory. Let us emphasize that there was little information available about the prior concepts of the population type (university students investigated in this research.

  20. CANFLEX fuel bundle junction pressure drop

    International Nuclear Information System (INIS)

    Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

    1996-11-01

    This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs

  1. CANFLEX fuel bundle junction pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

    1996-11-01

    This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs.

  2. 49 CFR 178.603 - Drop test.

    Science.gov (United States)

    2010-10-01

    ... used for the hydrostatic pressure or stacking test. Exceptions for the number of steel and aluminum..., non-resilient, flat and horizontal surface. (e) Drop height. Drop heights, measured as the vertical... than flat drops, the center of gravity of the test packaging must be vertically over the point of...

  3. Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding

    Energy Technology Data Exchange (ETDEWEB)

    Trushnikov, D. N., E-mail: trdimitr@yandex.ru [The department for Applied Physics, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation); Mladenov, G. M., E-mail: gmmladenov@abv.bg; Koleva, E. G., E-mail: eligeorg@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, 1784, Sofia (Bulgaria); Technology Centre of Electron Beam and Plasma Technologies and Techniques, 68-70 Vrania, ap.10, Banishora,1309, Sofia (Bulgaria); Belenkiy, V. Ya., E-mail: mtf@pstu.ru; Varushkin, S. V., E-mail: stepan.varushkin@mail.ru [The department for Welding Production and Technology of Constructional Materials, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation)

    2014-04-15

    Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup −3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A·m{sup −2}, i.e. 8 mA for a 3–10 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

  4. Transcranial electric stimulation for intraoperative motor evoked potential monitoring: dependence of required stimulation current on interstimulus interval value.

    Science.gov (United States)

    Joksimovic, Boban; Szelenyi, Andrea; Seifert, Volker; Damjanovic, Aleksandar; Damjanovic, Aleksandra; Rasulic, Lukas

    2015-05-01

    To evaluate the relationship between stimulus intensity by constant current transcranial electric stimulation and interstimulus interval (ISI) for eliciting muscle motor evoked potentials (MEPs) in three different hand muscles and the tibialis anterior muscles. We tested intraoperatively different monophasic constant current pulses and ISIs in 22 patients with clinically normal motor function. Motor thresholds of contralateral muscle MEPs were determined at 0.5 milliseconds (ms) pulse duration and ISIs of 1, 2, 3, 4, 5, and 10 ms using a train of 2, 3, and 5 monophasic constant current pulses of 62 to 104 mA before craniotomy and after closure of the dura mater. The lowest stimulation threshold to elicit MEPs in the examined muscles was achieved with a train of 5 pulses (ISI: 3 ms) before craniotomy, which was statistically significant compared with 2 pulses (ISI: 3 ms) as well as 3 pulses (ISIs: 3 and 10 ms). An ISI of 3 ms gave the lowest motor thresholds with statistical significance compared with the ISIs of 4 ms (2 pulses) and of 1 ms (3 pulses). All current intensity (mA) and ISI (ms) relationship graphs had a trend of the exponential function as y = a + bx + c ρ (x), where y is intensity (mA) and x is ISI (ms). The minimum of the function was determined for each patient and each muscle. The difference was statistically significant between 3 and 5 pulses before craniotomy and between 3 and 5 pulses and 2 and 5 pulses after closure of the dura mater. In adult neurosurgical patients with a normal motor status, a train of 5 pulses and an ISI of 3 ms provide the lowest motor thresholds. We provided evidence of the dependence of required stimulation current on ISI. Georg Thieme Verlag KG Stuttgart · New York.

  5. Electrohydrodynamics of a viscous drop with inertia.

    Science.gov (United States)

    Nganguia, H; Young, Y-N; Layton, A T; Lai, M-C; Hu, W-F

    2016-05-01

    Most of the existing numerical and theoretical investigations on the electrohydrodynamics of a viscous drop have focused on the creeping Stokes flow regime, where nonlinear inertia effects are neglected. In this work we study the inertia effects on the electrodeformation of a viscous drop under a DC electric field using a novel second-order immersed interface method. The inertia effects are quantified by the Ohnesorge number Oh, and the electric field is characterized by an electric capillary number Ca_{E}. Below the critical Ca_{E}, small to moderate electric field strength gives rise to steady equilibrium drop shapes. We found that, at a fixed Ca_{E}, inertia effects induce larger deformation for an oblate drop than a prolate drop, consistent with previous results in the literature. Moreover, our simulations results indicate that inertia effects on the equilibrium drop deformation are dictated by the direction of normal electric stress on the drop interface: Larger drop deformation is found when the normal electric stress points outward, and smaller drop deformation is found otherwise. To our knowledge, such inertia effects on the equilibrium drop deformation has not been reported in the literature. Above the critical Ca_{E}, no steady equilibrium drop deformation can be found, and often the drop breaks up into a number of daughter droplets. In particular, our Navier-Stokes simulations show that, for the parameters we use, (1) daughter droplets are larger in the presence of inertia, (2) the drop deformation evolves more rapidly compared to creeping flow, and (3) complex distribution of electric stresses for drops with inertia effects. Our results suggest that normal electric pressure may be a useful tool in predicting drop pinch-off in oblate deformations.

  6. An integrative view of cisplatin-induced renal and cardiac toxicities: molecular mechanisms, current treatment challenges and potential protective measures

    Science.gov (United States)

    Dugbartey, George J.; Peppone, Luke J.; de Graaf, Inge A.M.

    2017-01-01

    Cisplatin is currently one of the most widely-used chemotherapeutic agents against various malignancies. Its clinical application is limited, however, by inherent renal and cardiac toxicities and other side effects, of which the underlying mechanisms are only partly understood. Experimental studies show cisplatin generates reactive oxygen species, which impair the cell’s antioxidant defense system, causing oxidative stress and potentiating injury, thereby culminating in kidney and heart failure. Understanding the molecular mechanisms of cisplatin-induced renal and cardiac toxicities may allow clinicians to prevent or treat this problem better and may also provide a model for investigating drug-induced organ toxicity in general. This review discusses some of the major molecular mechanisms of cisplatin-induced renal and cardiac toxicities including disruption of ionic homeostasis and energy status of the cell leading to cell injury and cell death. We highlight clinical manifestations of both toxicities as well as (novel)biomarkers such as kidney injury molecule-1 (KIM-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). We also present some current treatment challenges and propose potential protective strategies with novel pharmacological compounds that might mitigate or prevent these toxicities, which include the use of hydrogen sulfide. PMID:27717837

  7. Capillary Thinning of Particle-laden Drops

    Science.gov (United States)

    Wagoner, Brayden; Thete, Sumeet; Jahns, Matt; Doshi, Pankaj; Basaran, Osman

    2015-11-01

    Drop formation is central in many applications such as ink-jet printing, microfluidic devices, and atomization. During drop formation, a thinning filament is created between the about-to-form drop and the fluid hanging from the nozzle. Therefore, the physics of capillary thinning of filaments is key to understanding drop formation and has been thoroughly studied for pure Newtonian fluids. The thinning dynamics is, however, altered completely when the fluid contains particles, the physics of which is not well understood. In this work, we explore the impact of solid particles on filament thinning and drop formation by using a combination of experiments and numerical simulations.

  8. Vibration-Induced Climbing of Drops

    Science.gov (United States)

    Brunet, P.; Eggers, J.; Deegan, R. D.

    2007-10-01

    We report an experimental study of liquid drops moving against gravity, when placed on a vertically vibrating inclined plate, which is partially wetted by the drop. The frequency of vibrations ranges from 30 to 200 Hz, and, above a threshold in vibration acceleration, drops experience an upward motion. We attribute this surprising motion to the deformations of the drop, as a consequence of an up or down symmetry breaking induced by the presence of the substrate. We relate the direction of motion to contact angle measurements. This phenomenon can be used to move a drop along an arbitrary path in a plane, without special surface treatments or localized forcing.

  9. Toward production from gas hydrates: Current status, assessment of resources, and simulation-based evaluation of technology and potential

    Science.gov (United States)

    Moridis, G.J.; Collett, T.S.; Boswell, R.; Kurihara, M.; Reagan, M.T.; Koh, C.; Sloan, E.D.

    2009-01-01

    Gas hydrates (GHs) are a vast energy resource with global distribution in the permafrost and in the oceans. Even if conservative estimates are considered and only a small fraction is recoverable, the sheer size of the resource is so large that it demands evaluation as a potential energy source. In this review paper, we discuss the distribution of natural GH accumulations, the status of the primary international research and development (R&D) programs, and the remaining science and technological challenges facing the commercialization of production. After a brief examination of GH accumulations that are well characterized and appear to be models for future development and gas production, we analyze the role of numerical simulation in the assessment of the hydrate-production potential, identify the data needs for reliable predictions, evaluate the status of knowledge with regard to these needs, discuss knowledge gaps and their impact, and reach the conclusion that the numerical-simulation capabilities are quite advanced and that the related gaps either are not significant or are being addressed. We review the current body of literature relevant to potential productivity from different types of GH deposits and determine that there are consistent indications of a large production potential at high rates across long periods from a wide variety of hydrate deposits. Finally, we identify (a) features, conditions, geology and techniques that are desirable in potential production targets; (b) methods to maximize production; and (c) some of the conditions and characteristics that render certain GH deposits undesirable for production. Copyright ?? 2009 Society of Petroleum Engineers.

  10. Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential

    Science.gov (United States)

    Capel, Rebecca A.; Herring, Neil; Kalla, Manish; Yavari, Arash; Mirams, Gary R.; Douglas, Gillian; Bub, Gil; Channon, Keith; Paterson, David J.; Terrar, Derek A.; Burton, Rebecca-Ann B.

    2015-01-01

    Background Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. Objectives The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardia. Methods We assessed the effects of HCQ on (1) cardiac beating rate in vitro (mice); (2) the “funny” current (If) in isolated guinea pig sinoatrial node (SAN) myocytes (1, 3, 10 µM); (3) heart rate and blood pressure in vivo by acute bolus injection (rat, dose range 1–30 mg/kg), (4) blood pressure and ventricular function during feeding (mouse, 100 mg/kg/d for 2 wk, tail cuff plethysmography, anesthetized echocardiography). Results In mouse atria, spontaneous beating rate was significantly (P < .05) reduced (by 9% ± 3% and 15% ± 2% at 3 and 10 µM HCQ, n = 7). In guinea pig isolated SAN cells, HCQ conferred a significant reduction in spontaneous action potential firing rate (17% ± 6%, 1 μM dose) and a dose-dependent reduction in If (13% ± 3% at 1 µM; 19% ± 2% at 3 µM). Effects were also observed on L-type calcium ion current (ICaL) (12% ± 4% reduction) and rapid delayed rectifier potassium current (IKr) (35% ± 4%) at 3 µM. Intravenous HCQ decreased heart rate in anesthetized rats (14.3% ± 1.1% at 15mg/kg; n = 6) without significantly reducing mean arterial blood pressure. In vivo feeding studies in mice showed no significant change in systolic blood pressure nor left ventricular function. Conclusions We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If. PMID:26025323

  11. Prostaglandin E2 potentiation of P2X3 receptor mediated currents in dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Huang Li-Yen

    2007-08-01

    Full Text Available Abstract Prostaglandin E2 (PGE2 is a well-known inflammatory mediator that enhances the excitability of DRG neurons. Homomeric P2X3 and heteromeric P2X2/3 receptors are abundantly expressed in dorsal root ganglia (DRG neurons and participate in the transmission of nociceptive signals. The interaction between PGE2 and P2X3 receptors has not been well delineated. We studied the actions of PGE2 on ATP-activated currents in dissociated DRG neurons under voltage-clamp conditions. PGE2 had no effects on P2X2/3 receptor-mediated responses, but significantly potentiated fast-inactivating ATP currents mediated by homomeric P2X3 receptors. PGE2 exerted its action by activating EP3 receptors. To study the mechanism underlying the action of PGE2, we found that the adenylyl cyclase activator, forskolin and the membrane-permeable cAMP analogue, 8-Br-cAMP increased ATP currents, mimicking the effect of PGE2. In addition, forskolin occluded the enhancement produced by PGE2. The protein kinase A (PKA inhibitors, H89 and PKA-I blocked the PGE2 effect. In contrast, the PKC inhibitor, bisindolymaleimide (Bis did not change the potentiating action of PGE2. We further showed that PGE2 enhanced α,β-meATP-induced allodynia and hyperalgesia and the enhancement was blocked by H89. These observations suggest that PGE2 binds to EP3 receptors, resulting in the activation of cAMP/PKA signaling pathway and leading to an enhancement of P2X3 homomeric receptor-mediated ATP responses in DRG neurons.

  12. Overview of current development in electrical energy storage technologies and the application potential in power system operation

    International Nuclear Information System (INIS)

    Luo, Xing; Wang, Jihong; Dooner, Mark; Clarke, Jonathan

    2015-01-01

    Highlights: • An overview of the state-of-the-art in Electrical Energy Storage (EES) is provided. • A comprehensive analysis of various EES technologies is carried out. • An application potential analysis of the reviewed EES technologies is presented. • The presented synthesis to EES technologies can be used to support future R and D and deployment. - Abstract: Electrical power generation is changing dramatically across the world because of the need to reduce greenhouse gas emissions and to introduce mixed energy sources. The power network faces great challenges in transmission and distribution to meet demand with unpredictable daily and seasonal variations. Electrical Energy Storage (EES) is recognized as underpinning technologies to have great potential in meeting these challenges, whereby energy is stored in a certain state, according to the technology used, and is converted to electrical energy when needed. However, the wide variety of options and complex characteristic matrices make it difficult to appraise a specific EES technology for a particular application. This paper intends to mitigate this problem by providing a comprehensive and clear picture of the state-of-the-art technologies available, and where they would be suited for integration into a power generation and distribution system. The paper starts with an overview of the operation principles, technical and economic performance features and the current research and development of important EES technologies, sorted into six main categories based on the types of energy stored. Following this, a comprehensive comparison and an application potential analysis of the reviewed technologies are presented

  13. Preferences of Current and Potential Patients and Family Members Regarding Implementation of Electronic Communication Portals in Intensive Care Units.

    Science.gov (United States)

    Brown, Samuel M; Bell, Sigall K; Roche, Stephanie D; Dente, Erica; Mueller, Ariel; Kim, Tae-Eun; O'Reilly, Kristin; Lee, Barbara Sarnoff; Sands, Ken; Talmor, Daniel

    2016-03-01

    The quality of communication with patients and family members in intensive care units (ICUs) is a focus of current interest for clinical care improvement. Electronic communication portals are commonly used in other healthcare settings to improve communication. We do not know whether patients and family members desire such portals in ICUs, and if so, what functionality they should provide. To define interest in and desired elements of an electronic communication portal among current and potential ICU patients and their family members. We surveyed, via an Internet panel, 1,050 English-speaking adults residing in the United States with a personal or family history of an ICU admission within 10 years (cohort A) and 1,050 individuals without a history of such admission (cohort B). We also administered a survey instrument in person to 105 family members of patients currently admitted to ICUs at an academic medical center in Boston (cohort C). Respondents, especially current ICU family members, supported an electronic communication portal, including access via an electronic tablet. They wanted at least daily updates, one-paragraph summaries of family meetings including a list of key decisions made, and knowledge of the role and experience of treating clinicians. Overall, they preferred detailed rather than "big picture" information. Respondents were generally comfortable sharing information with their family members. Preferences regarding a communication portal varied significantly by age, sex, ethnicity, and prior experience with ICU hospitalization. Electronic communication portals appear welcome in contemporary ICUs. Frequent updates, knowledge about the professional qualifications of clinicians, detailed medical information, and documentation of family meetings are particularly desired.

  14. Sodium Overload Due To a Persistent Current That Attenuates The Arrhythmogenic Potential of a Novel LQT3 Mutation

    Directory of Open Access Journals (Sweden)

    Adrien eMoreau

    2013-10-01

    Full Text Available Long QT syndrome (LQTS is a congenital abnormality of cardiac repolarization that manifests as a prolonged QT interval on 12-lead electrocardiograms. The syndrome may lead to syncope and sudden death from ventricular tachyarrhythmias known as torsades de pointes. An increased persistent Na+ current is known to cause a Ca2+ overload in case of ischemia for example. Such increased Na+ persistent current is also usually associated to the LQT3 syndrome. The purpose of this study was to investigate the pathological consequences of a novel mutation in a family affected by LQTS. The impact of biophysical defects on cellular homeostasis are also investigated.Genomic DNA was extracted from blood samples, and a combination of PCR and DNA sequencing of several LQTS-linked genes was used to identify mutations. The mutation was reproduced in vitro and was characterized using the patch clamp technique and in silico quantitative analysis.A novel mutation (Q1476R was identified on the SCN5A gene encoding the cardiac Na+ channel. Cells expressing the Q1476R mutation exhibited biophysical alterations, including a shift of SS inactivation and a significant increase in the persistent Na+ current. The in silico analysis confirmed the arrhythmogenic character of the Q1476R mutation. It further revealed that the increase in persistent Na+ current causes a frequency-dependent Na+ overload in cardiomyocytes co-expressing WT and mutant Nav1.5 channels, that, in turn, exerts a moderating effect on the lengthening of the action potential duration caused by the mutation.The Q1476R mutation in SCN5A results in a three-fold increase in the window current and a persistent inward Na+ current. These biophysical defects may expose the carrier of the mutation to arrhythmias that occur preferentially in the patient at rest or during tachycardia. However, the Na+ overload counterbalances the gain-of-function of the mutation and is beneficial in that it prevents severe arrhythmias at

  15. Who is dropping your course?

    Science.gov (United States)

    Storrs, Alex; Ghent, C.; Labattaglia, R.

    2011-01-01

    We present an analysis of pre and post instruction instruments in a basic astronomy course. This analysis is built on the Light and Spectroscopy Concept Inventory (LSCI, Bardar et al. 2007). In addition to assessing our student's gain in knowledge of this fundamental topic, we have added some demographic questions. While the primary purpose is to compare the gain in knowledge during a semester of instruction to changes in instruction, we also look at the demographics of students who take the pretest but not the posttest. These students are usually excluded from this type of analysis. We look for trends in the demographic information among students who drop the course, and suggest ways to make the course more palatable. References: Bardar et al., 2007: "Development and Validation of the Light and Spectroscopy Concept Inventory", Astr. Ed. Rev. 5(2), 103-113

  16. Magnetically focused liquid drop radiator

    Science.gov (United States)

    Botts, Thomas E.; Powell, James R.; Lenard, Roger

    1986-01-01

    A magnetically focused liquid drop radiator for application in rejecting rgy from a spacecraft, characterized by a magnetizable liquid or slurry disposed in operative relationship within the liquid droplet generator and its fluid delivery system, in combination with magnetic means disposed in operative relationship around a liquid droplet collector of the LDR. The magnetic means are effective to focus streams of droplets directed from the generator toward the collector, thereby to assure that essentially all of the droplets are directed into the collector, even though some of the streams may be misdirected as they leave the generator. The magnetic focusing means is also effective to suppress splashing of liquid when the droplets impinge on the collector.

  17. Surface potential, charging and local current transport of individual Ge quantum dots grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Singha, R.K. [Department of Physics, Visva-Bharati, Santiniketan 731235 (India); Manna, S.; Bar, R.; Das, S. [Department of Physics, Indian Institute of Technology-Kharagpur, Kharagpur 721302 (India); Ray, S.K., E-mail: physkr@phy.iitkgp.ernet.in [Department of Physics, Indian Institute of Technology-Kharagpur, Kharagpur 721302 (India)

    2017-06-15

    Highlights: We have elaborately explained the individual Ge QD charging phenomena and current transport, which is very important to understand the Ge/Si nano devices. This paper will give a flavor to properly understand these phenomena linked together along with the photocurrent mechanism which is related to the Ge/Si valence band offset. • Both the CAFM and KPFM techniques point out the functionality of doping nature of the underneath Si substrate on the aforementioned characteristics of Ge QDs. • Analysis of the surface potential mapping using KPFM technique yields an approximate valence band offset measurement which is required to understand the intra-valence transition of holes for the realization of long wavelength infrared photodetector. • KPFM and CAFM can be utilized to explore the charging/discharging phenomena of dots and their composition variations. • Current-voltage (I–V) characteristics of the individual Ge QD strongly depends on the individual QD size. • Energy band diagrams for diamond tip and Ge QD shows the higher barrier for electrons and lower barrier for holes allowing the easy tunneling for holes to dominate the transport. - Abstract: It is fundamentally important to understand the nanoscale electronic properties of a single quantum dot (QD) contrary to an ensemble of QDs. Kelvin probe force microscopy (KPFM) and conductive atomic force microscopy (CAFM) are two important tools, which could be employed to probe surface potential, charging phenomena, and current transport mechanism of individual QD. We demonstrate the aforementioned characteristics of self-assembled Ge QDs, which was grown on Si substrates by solid source molecular beam epitaxy driven by the Stranski-Krastanov method. Study reveals that each Ge QD acts as charge storage node even at zero applied bias. The shape, size and density of QDs could be well probed by CAFM and KPFM, whereas QD facets could be better resolved by the conductive tip. The CAFM investigation

  18. Changes in the action potential and transient outward potassium current in cardiomyocytes during acute cardiac rejection in rats.

    Science.gov (United States)

    Luo, Wenqi; Jia, Yixin; Zheng, Shuai; Li, Yan; Han, Jie; Meng, Xu

    2017-01-01

    Acute cardiac rejection contributes to the changes in the electrophysiological properties of grafted hearts. However, the electrophysiological changes of cardiomyocytes during acute cardiac rejection are still unknown. An understanding of the electrophysiological mechanisms of cardiomyocytes could improve the diagnosis and treatment of acute cardiac rejection. So it is important to characterize the changes in the action potential ( AP ) and the transient outward potassium current ( I to ) in cardiomyocytes during acute cardiac rejection. Heterotopic heart transplantation was performed in allogeneic [Brown Norway (BN)-to-Lewis] and isogeneic (BN-to-BN) rats. Twenty models were established in each group. Ten recipients were sacrificed at the 2nd day and the other ten recipients were sacrificed at the 4 th day after the operation in each group. Histopathological examinations of the grafted hearts were performed in half of the recipients in each group randomly. The other half of the grafted hearts were excised rapidly and enzymatically dissociated to obtain single cardiomyocytes. The AP and I to current were recorded using the whole cell patch-clamp technique. Forty grafted hearts were successfully harvested and used in experiments. Histologic examination showed mild rejection at the 2 nd day and moderate rejection at the 4 th day in the allogeneic group after cardiac transplantation, while no evidence of histologic lesions of rejection were observed in the isogeneic group. Compared with the isogeneic group, the action potential duration ( APD ) of cardiomyocytes in the allogeneic group was significantly prolonged ( APD 90 was 49.28±5.621 mV in the isogeneic group and 88.08±6.445 mV in the allogeneic group at the 2 nd day, P=0.0016; APD 90 was 59.34±5.183 mV in the isogeneic group and 104.0±9.523 mV in the allogeneic group at the 4 th day, P=0.0064). The current density of I to was significantly decreased at the 4 th day after cardiac transplantation. The APD of

  19. Hydrocarbon Degradation In Poultry Droppings And Cassava Peels ...

    African Journals Online (AJOL)

    This greenhouse study was aimed at determining the potentials of poultry droppings (PD) and cassava peels (CP) for nutrient-enhanced biodegradation of petroleum hydrocarbon (THC) in a well drained Typic Paleustults using the THC levels and degradation duration as remediation indices. The performance of the organic ...

  20. Tidal current energy potential of Nalón river estuary assessment using a high precision flow model

    Science.gov (United States)

    Badano, Nicolás; Valdés, Rodolfo Espina; Álvarez, Eduardo Álvarez

    2018-05-01

    Obtaining energy from tide currents in onshore locations is of great interest due to the proximity to the points of consumption. This opens the door to the feasibility of new installations based on hydrokinetic microturbines even in zones of moderate speed. In this context, the accuracy of energy predictions based on hydrodynamic models is of paramount importance. This research presents a high precision methodology based on a multidimensional hydrodynamic model that is used to study the energetic potential in estuaries. Moreover, it is able to estimate the flow variations caused by microturbine installations. The paper also shows the results obtained from the application of the methodology in a study of the Nalón river mouth (Asturias, Spain).

  1. Effects of electrical water bath stunning current frequencies on the spontaneous electroencephalogram and somatosensory evoked potentials in hens.

    Science.gov (United States)

    Raj, A B M; O'Callaghan, M

    2004-04-01

    1. The effectiveness of water bath electrical stunning of chickens with a constant root mean square (rms) current of 100 mA per bird delivered for 3 s using 100, 200, 400, 800 and 1500 Hz sine wave alternating current (AC) was investigated in layer hens. The quantitative changes occurring in the electroencephalogram (EEG) and somatosensory evoked potentials (SEPs) were used to determine the effectiveness of stunning. The changes occurring in the EEG were evaluated using Fast Fourier Transformations (FFT) and the SEPs were averaged to determine whether they were present or abolished. 2. The results of FFT indicated that stunning of chickens with a constant rms current of 100 mA per bird using 100 or 200 Hz induced epileptiform activity in all the hens, immediately followed by a reduction in the total (2 to 30 Hz) and relative (13 to 30 Hz) power contents in the EEG frequency bands indicative of unconsciousness and insensibility. The SEPs were abolished in the majority of hens stunned with 100 Hz and all the hens stunned with 200 Hz. 3. By contrast, stunning using 400, 800 or 1500 Hz failed to induce epileptiform activity in all the birds, the total and relative power contents in the EEG frequency bands showed a substantial increase, rather than reduction, and the SEPs were also retained in the majority of chickens. It is therefore suggested that stunning using these frequencies failed to stun them satisfactorily. In these birds, occurrence of a painful arousal, rather than unconsciousness, could not be ruled out. 4. It is therefore suggested that water bath electrical stunning of chickens with a minimum rms current of 100 mA per bird delivered using 100 or 200 Hz would be adequate to ensure bird welfare under commercial conditions, provided both the carotid arteries in the neck are severed at slaughter. On humanitarian and bird welfare grounds, a rms current of greater than 100 mA per bird should be applied whilst using frequencies of 400 Hz or more of sine wave AC

  2. Predicting the current and future potential distributions of lymphatic filariasis in Africa using maximum entropy ecological niche modelling.

    Directory of Open Access Journals (Sweden)

    Hannah Slater

    Full Text Available Modelling the spatial distributions of human parasite species is crucial to understanding the environmental determinants of infection as well as for guiding the planning of control programmes. Here, we use ecological niche modelling to map the current potential distribution of the macroparasitic disease, lymphatic filariasis (LF, in Africa, and to estimate how future changes in climate and population could affect its spread and burden across the continent. We used 508 community-specific infection presence data collated from the published literature in conjunction with five predictive environmental/climatic and demographic variables, and a maximum entropy niche modelling method to construct the first ecological niche maps describing potential distribution and burden of LF in Africa. We also ran the best-fit model against climate projections made by the HADCM3 and CCCMA models for 2050 under A2a and B2a scenarios to simulate the likely distribution of LF under future climate and population changes. We predict a broad geographic distribution of LF in Africa extending from the west to the east across the middle region of the continent, with high probabilities of occurrence in the Western Africa compared to large areas of medium probability interspersed with smaller areas of high probability in Central and Eastern Africa and in Madagascar. We uncovered complex relationships between predictor ecological niche variables and the probability of LF occurrence. We show for the first time that predicted climate change and population growth will expand both the range and risk of LF infection (and ultimately disease in an endemic region. We estimate that populations at risk to LF may range from 543 and 804 million currently, and that this could rise to between 1.65 to 1.86 billion in the future depending on the climate scenario used and thresholds applied to signify infection presence.

  3. Electrohydrodynamics of drops in strong electric fields: Simulations and theory

    Science.gov (United States)

    Saintillan, David; Das, Debasish

    2016-11-01

    Weakly conducting dielectric liquid drops suspended in another dielectric liquid exhibit a wide range of dynamical behaviors when subject to an applied uniform electric field contingent on field strength and material properties. These phenomena are best described by the much celebrated Maylor-Taylor leaky dielectric model that hypothesizes charge accumulation on the drop-fluid interface and prescribes a balance between charge relaxation, the jump in Ohmic currents and charge convection by the interfacial fluid flow. Most previous numerical simulations based on this model have either neglected interfacial charge convection or restricted themselves to axisymmetric drops. In this work, we develop a three-dimensional boundary element method for the complete leaky dielectric model to systematically study the deformation and dynamics of liquid drops in electric fields. The inclusion of charge convection in our simulation permits us to investigate drops in the Quincke regime, in which experiments have demonstrated symmetry-breaking bifurcations leading to steady electrorotation. Our simulation results show excellent agreement with existing experimental data and small deformation theories. ACSPRF Grant 53240-ND9.

  4. Neck extensor muscle weakness (Dropped head syndrome) following radiotherapy

    International Nuclear Information System (INIS)

    Bhatia, S.; Miller, R.C.; Lachance, D.L.

    2006-01-01

    Background. Dropped head syndrome is an unusual condition in which the head cannot be held upright in its normal anatomic position secondary to pronounced, isolated, neck extensor muscle weakness. Case report. A case of dropped head syndrome in a female with a history of radiotherapy for Hodgkin's lymphoma and a clinical history consistent with multiple sclerosis is presented, and potential etiologies are discussed. Conclusions. Muscular atrophy and lower motor neuron injury secondary to isolated anterior horn cell injury from radiotherapy emerge as the most likely etiology. (author)

  5. Medium carbon vanadium micro alloyed steels for drop forging

    International Nuclear Information System (INIS)

    Jeszensky, Gabor; Plaut, Ronald Lesley

    1992-01-01

    Growing competitiveness of alternative manufacturing routes requires cost minimization in the production of drop forged components. The authors analyse the potential of medium carbon, vanadium microalloyed steels for drop forging. Laboratory and industrial experiments have been carried out emphasizing deformation and temperature cycles, strain rates and dwell times showing a typical processing path, associated mechanical properties and corresponding microstructures. The steels the required levels of mechanical properties on cooling after forging, eliminating subsequent heat treatment. The machinability of V-microalloyed steels is also improved when compared with plain medium carbon steels. (author)

  6. GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C.; Ekechukwu, A.; Milliken, C.

    2011-05-17

    The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

  7. Single and combined metal contamination in coastal environments in China: current status and potential ecological risk evaluation.

    Science.gov (United States)

    Manzoor, Romana; Zhang, Tingwan; Zhang, Xuejiao; Wang, Min; Pan, Jin-Fen; Wang, Zhumei; Zhang, Bo

    2018-01-01

    With the development of industrialization and urbanization, metal and metalloid pollution is one of the most serious environmental problems in China. Current contamination status of metals and metalloid and their potential ecological risks along China's coasts were reviewed in the present paper by a comprehensive study on metal contents in marine waters and sediments in the past few decades. The priority metals/metalloid cadmium (Cd), mercury (Hg), chromium (Cr), lead (Pb), and arsenic (As), which were the target elements of the designated project "Comprehensive Prevention and Control of Heavy Metal Pollution" issued by the Chinese government in 2011, were selected considering their high toxicity, persistence, and prevalent existence in coastal environment. Commonly used environmental quality evaluation methods for single and combined metals were compared, and we accordingly suggest the comprehensive approach of joint utilization of the Enrichment Factor and Effect Range Median combined with Pollution Load Index and Mean Effect Range Median Quotient (EEPME); this battery of guidelines may provide consistent, internationally comparable, and accurate understanding of the environment pollution status of combined metals/metalloid and their potential ecological risk.

  8. Susceptibility of Aphelinus certus to foliar-applied insecticides currently or potentially registered for soybean aphid control.

    Science.gov (United States)

    Frewin, Andrew J; Schaafsma, Arthur W; Hallett, Rebecca H

    2012-02-01

    Soybean aphid, a serious economic pest of soybean in North America, is currently managed by applying non-selective foliar insecticides during outbreaks according to decision thresholds and crop maturity. Natural enemies, such as the parasitoid Aphelinus certus Yasnosh, potentially play an important role in suppressing soybean aphid. Using selective insecticides that preserve A. certus may enhance the biological control service they provide and thus prevent or reduce the severity of soybean aphid outbreaks. The toxicity of five insecticides (λ-cyhalothrin, dimethoate, flonicamid, mineral oil, spirotetramat) and the biopesticide Beauveria bassiana to A. certus was assessed. The LD50 values of λ-cyhalothrin and dimethoate were similar; however, the hazard quotient of dimethoate was greater than that of λ-cyhalothrin. In a screening bioassay, the descending order of toxicity for the recommended rates 48 h after application was dimethoate>λ-cyhalothrin>flonicamid>mineral oil>Beauveria bassiana>spirotetramat. Overall, λ-cyhalothrin and dimethoate were both harmful to A. certus. The other insecticides tested were harmless to A. certus and are potential candidates for inclusion in soybean aphid management programs. Copyright © 2011 Society of Chemical Industry.

  9. Mitigation potential of horizontal ground coupled heat pumps for current and future climatic conditions: UK environmental modelling and monitoring studies

    Science.gov (United States)

    García González, Raquel; Verhoef, Anne; Vidale, Pier Luigi; Gan, Guohui; Wu, Yupeng; Hughes, Andrew; Mansour, Majdi; Blyth, Eleanor; Finch, Jon; Main, Bruce

    2010-05-01

    model predictions of soil moisture content and soil temperature with measurements at different GCHP locations over the UK. The combined effect of environment dynamics and horizontal GCHP technical properties on long-term GCHP performance will be assessed using a detailed land surface model (JULES: Joint UK Land Environment Simulator, Meteorological Office, UK) with additional equations embedded describing the interaction between GCHP heat exchangers and the surrounding soil. However, a number of key soil physical processes are currently not incorporated in JULES, such as groundwater flow, which, especially in lowland areas, can have an important effect on the heat flow between soil and HE. Furthermore, the interaction between HE and soil may also cause soil vapour and moisture fluxes. These will affect soil thermal conductivity and hence heat flow between the HE and the surrounding soil, which will in turn influence system performance. The project will address these issues. We propose to drive an improved version of JULES (with equations to simulate GCHP exchange embedded), with long-term gridded (1 km) atmospheric, soil and vegetation data (reflecting current and future environmental conditions) to reliably assess the mitigation potential of GCHPs over the entire domain of the UK, where uptake of GCHPs has been low traditionally. In this way we can identify areas that are most suitable for the installation of GCHPs. Only then recommendations can be made to local and regional governments, for example, on how to improve the mitigation potential in less suitable areas by adjusting GCHP configurations or design.

  10. Ring-Sheared Drop (RSD): Microgravity Module for Containerless Flow Studies

    Science.gov (United States)

    Gulati, Shreyash; Raghunandan, Aditya; Rasheed, Fayaz; McBride, Samantha A.; Hirsa, Amir H.

    2017-02-01

    Microgravity is potentially a powerful tool for investigating processes that are sensitive to the presence of solid walls, since fluid containment can be achieved by surface tension. One such process is the transformation of protein in solution into amyloid fibrils; these are protein aggregates associated with neurodegenerative diseases such as Alzheimer's and Parkinson's. In addition to solid walls, experiments with gravity are also subject to influences from sedimentation of aggregates and buoyancy-driven convection. The ring-sheared drop (RSD) module is a flow apparatus currently under development to study formation of amyloid fibrils aboard the International Space Station (ISS). A 25 mm diameter drop of protein solution will be contained by surface tension and constrained by a pair of sharp-edged tubes, forming two contact rings. Shear can be imparted by rotating one ring with the other ring kept stationary. Here we report on parabolic flights conducted to test the growth and pinning of 10 mm diameter drops of water in under 10 s of microgravity. Finite element method (FEM) based fluid dynamics computations using a commercial package (COMSOL) assisted in the design of the parabolic flight experiments. Prior to the parabolic flights, the code was validated against experiments in the lab (1 g), on the growth of sessile and pendant droplets. The simulations show good agreement with the experiments. This modeling capability will enable the development of the RSD at the 25 mm scale for the ISS.

  11. Colony, hanging drop, and methylcellulose three dimensional hypoxic growth optimization of renal cell carcinoma cell lines.

    Science.gov (United States)

    Matak, Damian; Brodaczewska, Klaudia K; Lipiec, Monika; Szymanski, Łukasz; Szczylik, Cezary; Czarnecka, Anna M

    2017-08-01

    Renal cell carcinoma (RCC) is the most lethal of the common urologic malignancies, comprising 3% of all human neoplasms, and the incidence of kidney cancer is rising annually. We need new approaches to target tumor cells that are resistant to current therapies and that give rise to recurrence and treatment failure. In this study, we focused on low oxygen tension and three-dimensional (3D) cell culture incorporation to develop a new RCC growth model. We used the hanging drop and colony formation methods, which are common in 3D culture, as well as a unique methylcellulose (MC) method. For the experiments, we used human primary RCC cell lines, metastatic RCC cell lines, human kidney cancer stem cells, and human healthy epithelial cells. In the hanging drop assay, we verified the potential of various cell lines to create solid aggregates in hypoxic and normoxic conditions. With the semi-soft agar method, we also determined the ability of various cell lines to create colonies under different oxygen conditions. Different cell behavior observed in the MC method versus the hanging drop and colony formation assays suggests that these three assays may be useful to test various cell properties. However, MC seems to be a particularly valuable alternative for 3D cell culture, as its higher efficiency of aggregate formation and serum independency are of interest in different areas of cancer biology.

  12. Bacterial and fungal flora of seagull droppings in Jersey

    Science.gov (United States)

    Cragg, John; Clayton, Yvonne M.

    1971-01-01

    In Jersey 166 fresh and 122 dried seagull droppings were obtained and studied locally and in London for the presence of bacteria and fungi of potentially pathogenic nature. There were no salmonella or shigella bacteria isolated from the two groups but there was a high proportion of Candida albicans obtained from the fresh material (21·7%) and only 1·6% from the dry faeces. Cryptococcus neoformans and Histoplasma capsulatum were not found in either the dry or fresh droppings. The normal bacterial and fungal flora of the seagull was established and it is considered that the C. albicans in fresh gull droppings would not materially increase albicans infections in man. PMID:5104846

  13. Green chemistry and nanofabrication in a levitated Leidenfrost drop

    Science.gov (United States)

    Abdelaziz, Ramzy; Disci-Zayed, Duygu; Hedayati, Mehdi Keshavarz; Pöhls, Jan-Hendrik; Zillohu, Ahnaf Usman; Erkartal, Burak; Chakravadhanula, Venkata Sai Kiran; Duppel, Viola; Kienle, Lorenz; Elbahri, Mady

    2013-10-01

    Green nanotechnology focuses on the development of new and sustainable methods of creating nanoparticles, their localized assembly and integration into useful systems and devices in a cost-effective, simple and eco-friendly manner. Here we present our experimental findings on the use of the Leidenfrost drop as an overheated and charged green chemical reactor. Employing a droplet of aqueous solution on hot substrates, this method is capable of fabricating nanoparticles, creating nanoscale coatings on complex objects and designing porous metal in suspension and foam form, all in a levitated Leidenfrost drop. As examples of the potential applications of the Leidenfrost drop, fabrication of nanoporous black gold as a plasmonic wideband superabsorber, and synthesis of superhydrophilic and thermal resistive metal-polymer hybrid foams are demonstrated. We believe that the presented nanofabrication method may be a promising strategy towards the sustainable production of functional nanomaterials.

  14. Sepsis from dropped clips at laparoscopic cholecystectomy

    International Nuclear Information System (INIS)

    Hussain, Sarwat

    2001-01-01

    We report seven patients in whom five dropped surgical clips and two gallstones were visualized in the peritoneal cavity, on radiological studies. In two, subphrenic abscesses and empyemas developed as a result of dropped clips into the peritoneal cavity during or following laparoscopic cholecystectomy. In one of these two, a clip was removed surgically from the site of an abscess. In two other patients dropped gallstones, and in three, dropped clips led to no complications. These were seen incidentally on studies done for other indications. Abdominal abscess secondary to dropped gallstones is a well-recognized complication of laparoscopic cholecystectomy (LC). We conclude that even though dropped surgical clips usually do not cause problems, they should be considered as a risk additional to other well-known causes of post-LC abdominal sepsis

  15. Hydrothermal waves in evaporating sessile drops

    OpenAIRE

    Brutin, D.; Rigollet, F.; Niliot, C. Le

    2009-01-01

    Drop evaporation is a simple phenomena but still unclear concerning the mechanisms of evaporation. A common agreement of the scientific community based on experimental and numerical work evidences that most of the evaporation occurs at the triple line. However, the rate of evaporation is still empirically predicted due to the lack of knowledge on the convection cells which develop inside the drop under evaporation. The evaporation of sessile drop is more complicated than it appears due to the...

  16. White Paper: Interventional MRI: Current Status and Potential for Development Considering Economic Perspectives, Part 1: General Application.

    Science.gov (United States)

    Barkhausen, Jörg; Kahn, Thomas; Krombach, Gabriele A; Kuhl, Christiane K; Lotz, Joachim; Maintz, David; Ricke, Jens; Schönberg, Stefan O; Vogl, Thomas J; Wacker, Frank K

    2017-07-01

    children with congenital heart defects and for atrial ablation at individual centers. Greater application can be expected in the future.. Citation format · Barkhausen J, Kahn T, Krombach GA et al. White Paper: Interventional MRI: Current Status and Potential for Development Considering Economic Perspectives, Part 1: General Application. Fortschr Röntgenstr 2017; 189: 611 - 623. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Parametric resonance in acoustically levitated water drops

    International Nuclear Information System (INIS)

    Shen, C.L.; Xie, W.J.; Wei, B.

    2010-01-01

    Liquid drops can be suspended in air with acoustic levitation method. When the sound pressure is periodically modulated, the levitated drop is usually forced into an axisymmetric oscillation. However, a transition from axisymmetric oscillation into sectorial oscillation occurs when the modulation frequency approaches some specific values. The frequency of the sectorial oscillation is almost exactly half of the modulation frequency. It is demonstrated that this transition is induced by the parametric resonance of levitated drop. The natural frequency of sectorial oscillation is found to decrease with the increase of drop distortion extent.

  18. Parametric resonance in acoustically levitated water drops

    Energy Technology Data Exchange (ETDEWEB)

    Shen, C.L.; Xie, W.J. [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China); Wei, B., E-mail: bbwei@nwpu.edu.c [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2010-05-10

    Liquid drops can be suspended in air with acoustic levitation method. When the sound pressure is periodically modulated, the levitated drop is usually forced into an axisymmetric oscillation. However, a transition from axisymmetric oscillation into sectorial oscillation occurs when the modulation frequency approaches some specific values. The frequency of the sectorial oscillation is almost exactly half of the modulation frequency. It is demonstrated that this transition is induced by the parametric resonance of levitated drop. The natural frequency of sectorial oscillation is found to decrease with the increase of drop distortion extent.

  19. Soft drop jet mass measurement

    CERN Document Server

    Roloff, Jennifer Kathryn; The ATLAS collaboration

    2018-01-01

    Calculations of jet substructure observables that are accurate beyond leading-logarithm accuracy have recently become available. Such observables are significant not only for probing the collinear regime of QCD that is largely unexplored at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many studies at the Large Hadron Collider. This poster documents a measurement of the first jet substructure quantity at a hadron collider to be calculated at next-to-next-to-leading-logarithm accuracy. The normalized, differential cross-section is measured as a function of log( ρ^2), where ρ is the ratio of the soft-drop mass to the ungroomed jet transverse momentum. This quantity is measured in dijet events from 32.9 ifb of sqrt(s) = 13 TeV proton-proton collisions recorded by the ATLAS detector. The data are unfolded to correct for detector effects and compared to precise QCD calculations and leading-logarithm particle-level Monte Carlo simulations.

  20. Role of action potential configuration and the contribution of C²⁺a and K⁺ currents to isoprenaline-induced changes in canine ventricular cells.

    Science.gov (United States)

    Szentandrássy, N; Farkas, V; Bárándi, L; Hegyi, B; Ruzsnavszky, F; Horváth, B; Bányász, T; Magyar, J; Márton, I; Nánási, P P

    2012-10-01

    Although isoprenaline (ISO) is known to activate several ion currents in mammalian myocardium, little is known about the role of action potential morphology in the ISO-induced changes in ion currents. Therefore, the effects of ISO on action potential configuration, L-type Ca²⁺ current (I(Ca)), slow delayed rectifier K⁺ current (I(Ks)) and fast delayed rectifier K⁺ current (I(Kr)) were studied and compared in a frequency-dependent manner using canine isolated ventricular myocytes from various transmural locations. Action potentials were recorded with conventional sharp microelectrodes; ion currents were measured using conventional and action potential voltage clamp techniques. In myocytes displaying a spike-and-dome action potential configuration (epicardial and midmyocardial cells), ISO caused reversible shortening of action potentials accompanied by elevation of the plateau. ISO-induced action potential shortening was absent in endocardial cells and in myocytes pretreated with 4-aminopyridine. Application of the I(Kr) blocker E-4031 failed to modify the ISO effect, while action potentials were lengthened by ISO in the presence of the I(Ks) blocker HMR-1556. Both action potential shortening and elevation of the plateau were prevented by pretreatment with the I(Ca) blocker nisoldipine. Action potential voltage clamp experiments revealed a prominent slowly inactivating I(Ca) followed by a rise in I(Ks) , both currents increased with increasing the cycle length. The effect of ISO in canine ventricular cells depends critically on action potential configuration, and the ISO-induced activation of I(Ks) - but not I(Kr) - may be responsible for the observed shortening of action potentials. © 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.

  1. Role of action potential configuration and the contribution of Ca2+ and K+ currents to isoprenaline-induced changes in canine ventricular cells

    Science.gov (United States)

    Szentandrássy, N; Farkas, V; Bárándi, L; Hegyi, B; Ruzsnavszky, F; Horváth, B; Bányász, T; Magyar, J; Márton, I; Nánási, PP

    2012-01-01

    BACKGROUND AND PURPOSE Although isoprenaline (ISO) is known to activate several ion currents in mammalian myocardium, little is known about the role of action potential morphology in the ISO-induced changes in ion currents. Therefore, the effects of ISO on action potential configuration, L-type Ca2+ current (ICa), slow delayed rectifier K+ current (IKs) and fast delayed rectifier K+ current (IKr) were studied and compared in a frequency-dependent manner using canine isolated ventricular myocytes from various transmural locations. EXPERIMENTAL APPROACH Action potentials were recorded with conventional sharp microelectrodes; ion currents were measured using conventional and action potential voltage clamp techniques. KEY RESULTS In myocytes displaying a spike-and-dome action potential configuration (epicardial and midmyocardial cells), ISO caused reversible shortening of action potentials accompanied by elevation of the plateau. ISO-induced action potential shortening was absent in endocardial cells and in myocytes pretreated with 4-aminopyridine. Application of the IKr blocker E-4031 failed to modify the ISO effect, while action potentials were lengthened by ISO in the presence of the IKs blocker HMR-1556. Both action potential shortening and elevation of the plateau were prevented by pretreatment with the ICa blocker nisoldipine. Action potential voltage clamp experiments revealed a prominent slowly inactivating ICa followed by a rise in IKs, both currents increased with increasing the cycle length. CONCLUSIONS AND IMPLICATIONS The effect of ISO in canine ventricular cells depends critically on action potential configuration, and the ISO-induced activation of IKs– but not IKr– may be responsible for the observed shortening of action potentials. PMID:22563726

  2. Electric potential behaviour in segmented Faraday-type MHD generators

    International Nuclear Information System (INIS)

    James, M.I.; Mittal, M.L.; Gupta, G.P.; Rohatgi, V.K.

    1985-01-01

    The potential distribution in the transverse cross-section of a segmented Faraday-type MHD generator is studied. The governing elliptic equation, derived with allowance for the finite electrode segmentation effect and nonuniformity of the gas in the channel, is solved numerically using the Alternating Direction Implicit method in the finite difference scheme, instead of the successive over-relaxation method. The computed potential distribution and the potential drops are found to compare well with experimental results. The potential drops at the electrodes are found to increase with increasing current density. (author)

  3. Surface potential distribution and airflow performance of different air-exposed electrode plasma actuators at different alternating current/direct current voltages

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liang; Yan, Hui-Jie; Qi, Xiao-Hua; Hua, Yue; Ren, Chun-Sheng, E-mail: rchsh@dlut.edu.cn [School of Physics and Optoelectronic Technology, Key laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116023 (China)

    2015-04-15

    Asymmetric surface dielectric barrier discharge (SDBD) plasma actuators have been intensely studied for a number of years due to their potential applications for aerodynamic control. In this paper, four types of actuators with different configurations of exposed electrode are proposed. The SDBD actuators investigated are driven by dual-power supply, referred to as a fixed AC high voltage and an adjustable DC bias. The effects of the electrode structures on the dielectric surface potential distribution, the electric wind velocity, and the mean thrust production are studied, and the dominative factors of airflow acceleration behavior are revealed. The results have shown that the actions of the SDBD actuator are mainly dependent on the geometry of the exposed electrode. Besides, the surface potential distribution can effectively affect the airflow acceleration behavior. With the application of an appropriate additional DC bias, the surface potential will be modified. As a result, the performance of the electric wind produced by a single SDBD can be significantly improved. In addition, the work also illustrates that the actuators with more negative surface potential present better mechanical performance.

  4. Surface potential distribution and airflow performance of different air-exposed electrode plasma actuators at different alternating current/direct current voltages

    International Nuclear Information System (INIS)

    Yang, Liang; Yan, Hui-Jie; Qi, Xiao-Hua; Hua, Yue; Ren, Chun-Sheng

    2015-01-01

    Asymmetric surface dielectric barrier discharge (SDBD) plasma actuators have been intensely studied for a number of years due to their potential applications for aerodynamic control. In this paper, four types of actuators with different configurations of exposed electrode are proposed. The SDBD actuators investigated are driven by dual-power supply, referred to as a fixed AC high voltage and an adjustable DC bias. The effects of the electrode structures on the dielectric surface potential distribution, the electric wind velocity, and the mean thrust production are studied, and the dominative factors of airflow acceleration behavior are revealed. The results have shown that the actions of the SDBD actuator are mainly dependent on the geometry of the exposed electrode. Besides, the surface potential distribution can effectively affect the airflow acceleration behavior. With the application of an appropriate additional DC bias, the surface potential will be modified. As a result, the performance of the electric wind produced by a single SDBD can be significantly improved. In addition, the work also illustrates that the actuators with more negative surface potential present better mechanical performance

  5. Non-Chemical Stressors and Cumulative Risk Assessment: An Overview of Current Initiatives and Potential Air Pollutant Interactions

    Science.gov (United States)

    Lewis, Ari S.; Sax, Sonja N.; Wason, Susan C.; Campleman, Sharan L.

    2011-01-01

    Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit

  6. Drop Impact Dynamics with Sessile Drops and Geometries: Spreading, Jetting, and Fragmentation

    Science.gov (United States)

    Tilger, Christopher F.

    The tendency of surface tension to cause small parcels of fluid to form into drops allows convenient packaging, transport, dispersal of liquid phase matter. Liquid drop impacts with solids, liquids, and other drops have realized and additional future applications in biological, manufacturing, heat transfer, and combustion systems. Experiments were conducted to investigate the dynamics of multiple drop collisions, rather than the most-studied phenomenon of single drop impacts. Additional drop impacts were performed on rigid hemispheres representing sessile drops, angled substrates, and into the vertex of two tilted surfaces arranged into a vee shape. A qualitative inspection of drop-sessile drop impacts shows distinct post-impact shapes depending on the offset distance between the drops. At intermediate offset distances, distinct jets issue from the overlap region between the two drops projected areas. These jets are observed to reach their maximum extent at a critical offset distance ratio, epsilon epsilon ˜ 0.75-0.80, with substrate contact angle and W e having a lesser effect. Capillary waves that traverse the sessile drop after collision cause a lower aspect ratio liquid column to emanate from the sessile drop opposite the impact. In order to better understand the jetting phenomenon seen in the offset drop-sessile drop impacts, simpler solid geometries are investigated that elicit a similar behavior. Solid hemispheres do not show the singular jetting observed in the fluidic case, however, a simple vee formed by two intersection planar substrates do jet in a similar fashion to the fluidic case. A geometric model with partnered experiments is developed to describe the bisymmetric spread of an impacting drop on an angled substrate. This geometric model is used to guide a time of arrival based model for various features of the drop impact, which is used to predict jetting in various vee channel experiments.

  7. Assessment of Power Potential of Tidal Currents and Impacts of Power Extraction on Flow Conditions in Indonesia

    Science.gov (United States)

    Orhan, Kadir; Mayerle, Roberto

    2017-04-01

    Climate change is an urgent and potentially irreversible threat to human societies and the planet and thus requires an effective and appropriate response, with a view to accelerating the reduction of global greenhouse gas emissions. At this point, a worldwide shift to renewable energy is crucial. In this study, a methodology comprising of the estimates of power yield, evaluation of the effects of power extraction on flow conditions, and near-field investigations to deliver wake characteristics, recovery and interactions is described and applied to several straits in Indonesia. Site selection is done with high-resolution, three-dimensional flow models providing sufficient spatiotemporal coverage. Much attention has been given to the meteorological forcing, and conditions at the open sea boundaries to adequately capture the density gradients and flow fields. Model verifications using tidal records show excellent agreement. Sites with adequate depth for the energy conversion using horizontal axis tidal turbines, average kinetic power density greater than 0.5 kW/m2, and surface area larger than 0.5km2 are defined as energy hotspots. Spatial variation of the average extractable electric power is determined, and annual tidal energy resource is estimated for the straits in question. The results showed that the potential for tidal power generation in Indonesia is likely to exceed previous predictions reaching around 4,800MW. Models with higher resolutions have been developed to assess the impacts of devices on flow conditions and to resolve near-field turbine wakes in greater detail. The energy is assumed to be removed uniformly by sub-grid scale arrays of turbines. An additional drag force resulting in dissipation of the pre-existing kinetic power from 10% to 60% within a flow cross-section is introduced to capture the impacts. k-ɛ model, which is a second order turbulence closure model is selected to involve the effects of the turbulent kinetic energy and turbulent

  8. Sustained attention in skilled and novice martial arts athletes: a study of event-related potentials and current sources.

    Science.gov (United States)

    Sanchez-Lopez, Javier; Silva-Pereyra, Juan; Fernandez, Thalia

    2016-01-01

    Background. Research on sports has revealed that behavioral responses and event-related brain potentials (ERP) are better in expert than in novice athletes for sport-related tasks. Focused attention is essential for optimal athletic performance across different sports but mainly in combat disciplines. During combat, long periods of focused attention (i.e., sustained attention) are required for a good performance. Few investigations have reported effects of expertise on brain electrical activity and its neural generators during sport-unrelated attention tasks. The aim of the present study was to assess the effect of expertise (i.e., skilled and novice martial arts athletes) analyzing the ERP during a sustained attention task (Continuous Performance Task; CPT) and the cortical three-dimensional distribution of current density, using the sLORETA technique. Methods. CPT consisted in an oddball-type paradigm presentation of five stimuli (different pointing arrows) where only one of them (an arrow pointing up right) required a motor response (i.e., target). CPT was administered to skilled and novice martial arts athletes while EEG were recorded. Amplitude ERP data from target and non-target stimuli were compared between groups. Subsequently, current source analysis for each ERP component was performed on each subject. sLORETA images were compared by condition and group using Statistical Non-Parametric Mapping analysis. Results. Skilled athletes showed significant amplitude differences between target and non-target conditions in early ERP components (P100 and P200) as opposed to the novice group; however, skilled athletes showed no significant effect of condition in N200 but novices did show a significant effect. Current source analysis showed greater differences in activations in skilled compared with novice athletes between conditions in the frontal (mainly in the Superior Frontal Gyrus and Medial Frontal Gyrus) and limbic (mainly in the Anterior Cingulate Gyrus) lobes

  9. Divalent ion block of inward rectifier current in human capillary endothelial cells and effects on resting membrane potential

    Science.gov (United States)

    Jow, Flora; Numann, Randy

    1998-01-01

    Cultured human capillary endothelial cells (HCEC) contain a large inward rectifier current, IK(IR), that can be abolished by removing external K+ or by adding 50 μm Ba2+.We show that IK(IR) is responsible for maintaining the hyperpolarized potential (−60.6 ± 0.5 mV, n = 83) of HCEC. Blocking IK(IR) with 50 μm Ba2+ shifts the zero current level and depolarizes HCEC by 36.5 ± 1.3 mV (n = 4).Increasing external Ca2+ concentration ([Ca2+]o) from 0.5 to 7 mm reduces the magnitude of IK(IR) by 36.5 ± 2.3 % (n = 5) and depolarizes the cells by 10.33 ± 2.4 mV (n = 3), whereas decreasing [Ca2+]o from 1.8 to 0.5 mm increases the amplitude of IK(IR) by 6.9 ± 1.9 % (n = 4). The relationship between [Ca2+]o and the percentage block of IK(IR) gives a Kd value of 5.4 ± 0.6 mm at −120 mV.IK(IR) is also blocked by other divalent ions, with Ba2+ >> Sr2+ > Mg2+ > Mn2+= Ca2+, and the block of peak current at −120 mV being 85.3 ± 3.2 % (n = 5) for 50 μm Ba2+, 62.9 ± 2.2 % (n = 5) for 5 mm Sr2+, 40.7 ± 2.5 % (n = 9) for 5 mm Mg2+, 33.4 ± 2.1 % (n = 5) for 5 mm Mn2+ and 32.9 ± 2.1 % (n = 5) for 5 mm Ca2+.The voltage dependence of Sr2+ block of peak IK(IR) occurred with a Kd value of 1.0 ± 0.09 mm for −140 mV, 1.9 ± 0.16 mm for −130 mV, 3.1 ± 0.28 mm for −120 mV, 4.6 ± 0.34 mm for −110 mV and 6.4 ± 0.5 mm for −100 mV (n = 5), with a calculated electrical distance (δ) of 0.44 from the outside. PMID:9729622

  10. Many Drops Make a Lake

    Directory of Open Access Journals (Sweden)

    Chaitanya S. Mudgal

    2014-03-01

    greater knowledge, better skills and disseminate this knowledge through this journal to influence as many physicians and their patients as possible. They have taken the knowledge of their teachers, recognized their giants and are now poised to see further than ever before. My grandmother often used to quote to me a proverb from India, which when translated literally means “Many drops make a lake”. I cannot help but be amazed by the striking similarities between the words of Newton and this Indian saying. Therefore, while it may seem intuitive, I think it must be stated that it is vital for the betterment of all our patients that we recognize our own personal lakes to put our drops of knowledge into. More important is that we recognize that it is incumbent upon each and every one of us to contribute to our collective lakes of knowledge such as ABJS. And finally and perhaps most importantly we need to be utterly cognizant of never letting such lakes of knowledge run dry.... ever.

  11. Physical Watermarking for Securing Cyber-Physical Systems via Packet Drop Injections

    Energy Technology Data Exchange (ETDEWEB)

    Ozel, Omur [Carnegie Mellon Univ., Pittsburgh, PA (United States); Weekrakkody, Sean [Carnegie Mellon Univ., Pittsburgh, PA (United States); Sinopoli, Bruno [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2017-10-23

    Physical watermarking is a well known solution for detecting integrity attacks on Cyber-Physical Systems (CPSs) such as the smart grid. Here, a random control input is injected into the system in order to authenticate physical dynamics and sensors which may have been corrupted by adversaries. Packet drops may naturally occur in a CPS due to network imperfections. To our knowledge, previous work has not considered the role of packet drops in detecting integrity attacks. In this paper, we investigate the merit of injecting Bernoulli packet drops into the control inputs sent to actuators as a new physical watermarking scheme. With the classical linear quadratic objective function and an independent and identically distributed packet drop injection sequence, we study the effect of packet drops on meeting security and control objectives. Our results indicate that the packet drops could act as a potential physical watermark for attack detection in CPSs.

  12. Self-wrapping of an ouzo drop induced by evaporation on a superamphiphobic surface

    NARCIS (Netherlands)

    Tan, H.; Diddens, C.; Versluis, M.; Butt, H.J.; Lohse, D.; Zhang, X.

    2017-01-01

    Evaporation of multi-component drops is crucial to various technologies and has numerous potential applications because of its ubiquity in nature. Superamphiphobic surfaces, which are both superhydrophobic and superoleophobic, can give a low wettability not only for water drops but also for oil

  13. Review of the current understanding of the potential for containment failure from in-vessel steam explosions

    International Nuclear Information System (INIS)

    1985-06-01

    A group of experts was convened to review the current understanding of the potential for containment failure from in-vessel steam explosions during core meltdown accidents in LWRs. The Steam Explosion Review Group (SERG) was requested to provide assessments of: (1) the conditional probability of containment failure due to a steam explosion, (2) a Sandia National Laboratory (SNL) report entitled ''An Uncertainty Study of PWR Steam Explosions,'' NUREG/CR-3369, (3) a SNL proposed steam explosion research program. This report summarizes the results of the deliberations of the review group. It also presents the detailed response of each individual member to each of the issues. The consensus of the SERG is that the occurrence of a steam explosion of sufficient energetics which could lead to alpha-mode containment failure has a low probability. The SERG members disagreed with the methodology used in NUREG/CR-3369 for the purpose of establishing the uncertainty in the probability of containment failure by a steam explosion. A consensus was reached among SERG members on the need for a continuing steam explosion research program which would improve our understanding of certain aspects of steam explosion phenomenology

  14. Low Resting Membrane Potential and Low Inward Rectifier Potassium Currents Are Not Inherent Features of hiPSC-Derived Cardiomyocytes.

    Science.gov (United States)

    Horváth, András; Lemoine, Marc D; Löser, Alexandra; Mannhardt, Ingra; Flenner, Frederik; Uzun, Ahmet Umur; Neuber, Christiane; Breckwoldt, Kaja; Hansen, Arne; Girdauskas, Evaldas; Reichenspurner, Hermann; Willems, Stephan; Jost, Norbert; Wettwer, Erich; Eschenhagen, Thomas; Christ, Torsten

    2018-03-13

    Human induced pluripotent stem cell (hiPSC) cardiomyocytes (CMs) show less negative resting membrane potential (RMP), which is attributed to small inward rectifier currents (I K1 ). Here, I K1 was measured in hiPSC-CMs (proprietary and commercial cell line) cultured as monolayer (ML) or 3D engineered heart tissue (EHT) and, for direct comparison, in CMs from human right atrial (RA) and left ventricular (LV) tissue. RMP was measured in isolated cells and intact tissues. I K1 density in ML- and EHT-CMs from the proprietary line was similar to LV and RA, respectively. I K1 density in EHT-CMs from the commercial line was 2-fold smaller than in the proprietary line. RMP in EHT of both lines was similar to RA and LV. Repolarization fraction and I K,ACh response discriminated best between RA and LV and indicated predominantly ventricular phenotype in hiPSC-CMs/EHT. The data indicate that I K1 is not necessarily low in hiPSC-CMs, and technical issues may underlie low RMP in hiPSC-CMs. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  15. The effect of transcranial direct current stimulation on contrast sensitivity and visual evoked potential amplitude in adults with amblyopia.

    Science.gov (United States)

    Ding, Zhaofeng; Li, Jinrong; Spiegel, Daniel P; Chen, Zidong; Chan, Lily; Luo, Guangwei; Yuan, Junpeng; Deng, Daming; Yu, Minbin; Thompson, Benjamin

    2016-01-14

    Amblyopia is a neurodevelopmental disorder of vision that occurs when the visual cortex receives decorrelated inputs from the two eyes during an early critical period of development. Amblyopic eyes are subject to suppression from the fellow eye, generate weaker visual evoked potentials (VEPs) than fellow eyes and have multiple visual deficits including impairments in visual acuity and contrast sensitivity. Primate models and human psychophysics indicate that stronger suppression is associated with greater deficits in amblyopic eye contrast sensitivity and visual acuity. We tested whether transcranial direct current stimulation (tDCS) of the visual cortex would modulate VEP amplitude and contrast sensitivity in adults with amblyopia. tDCS can transiently alter cortical excitability and may influence suppressive neural interactions. Twenty-one patients with amblyopia and twenty-seven controls completed separate sessions of anodal (a-), cathodal (c-) and sham (s-) visual cortex tDCS. A-tDCS transiently and significantly increased VEP amplitudes for amblyopic, fellow and control eyes and contrast sensitivity for amblyopic and control eyes. C-tDCS decreased VEP amplitude and contrast sensitivity and s-tDCS had no effect. These results suggest that tDCS can modulate visual cortex responses to information from adult amblyopic eyes and provide a foundation for future clinical studies of tDCS in adults with amblyopia.

  16. Algorithms for Computing the Magnetic Field, Vector Potential, and Field Derivatives for a Thin Solenoid with Uniform Current Density

    Energy Technology Data Exchange (ETDEWEB)

    Walstrom, Peter Lowell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-07

    A numerical algorithm for computing the field components Br and Bz and their r and z derivatives with open boundaries in cylindrical coordinates for radially thin solenoids with uniform current density is described in this note. An algorithm for computing the vector potential Aθ is also described. For the convenience of the reader, derivations of the final expressions from their defining integrals are given in detail, since their derivations are not all easily found in textbooks. Numerical calculations are based on evaluation of complete elliptic integrals using the Bulirsch algorithm cel. The (apparently) new feature of the algorithms described in this note applies to cases where the field point is outside of the bore of the solenoid and the field-point radius approaches the solenoid radius. Since the elliptic integrals of the third kind normally used in computing Bz and Aθ become infinite in this region of parameter space, fields for points with the axial coordinate z outside of the ends of the solenoid and near the solenoid radius are treated by use of elliptic integrals of the third kind of modified argument, derived by use of an addition theorem. Also, the algorithms also avoid the numerical difficulties the textbook solutions have for points near the axis arising from explicit factors of 1/r or 1/r2 in the some of the expressions.

  17. Algorithms for Computing the Magnetic Field, Vector Potential, and Field Derivatives for Circular Current Loops in Cylindrical Coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Walstrom, Peter Lowell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-24

    A numerical algorithm for computing the field components Br and Bz and their r and z derivatives with open boundaries in cylindrical coordinates for circular current loops is described. An algorithm for computing the vector potential is also described. For the convenience of the reader, derivations of the final expressions from their defining integrals are given in detail, since their derivations (especially for the field derivatives) are not all easily found in textbooks. Numerical calculations are based on evaluation of complete elliptic integrals using the Bulirsch algorithm cel. Since cel can evaluate complete elliptic integrals of a fairly general type, in some cases the elliptic integrals can be evaluated without first reducing them to forms containing standard Legendre forms. The algorithms avoid the numerical difficulties that many of the textbook solutions have for points near the axis because of explicit factors of 1=r or 1=r2 in the some of the expressions.

  18. Potential contribution of currently operating nuclear-fueled electric-generating units to reducing US oil consumption

    International Nuclear Information System (INIS)

    Koppe, R.H.; Olson, E.A.J.; Van Howe, K.R.

    1980-01-01

    This study examines the prospect for performance improvement in the 62 light water reactors in operation in the US as of the end of last year and which are deemed to have current commercial design features. These units represent a total net capacity of 49,481 MW(e). In the last two years (1978 to 1979), total capacity factor losses for these units was 36.5%. This study finds that in the short-term, capacity factor improvement of about 16% could be achieved, for example, in response to a short-term energy crisis. In the long-term a gain of perhaps 18% could be achieved. Such gains would represent a decrease in equivalent oil consumption of approximately 350,000 barrels a day. In addition, this study evaluated potential increases in the operating power level of these units, and concluded that a short term power level increase of about 2500 MW(e) could be achieved, in addition to a long term increase of about 1700 MW(e). This total short term power level increase would be equivalent to 138,000 barrels of oil per day

  19. Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography.

    Science.gov (United States)

    Attenberger, Ulrike I; Morelli, John; Budjan, Johannes; Henzler, Thomas; Sourbron, Steven; Bock, Michael; Riffel, Philipp; Hernando, Diego; Ong, Melissa M; Schoenberg, Stefan O

    2015-09-01

    Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.

  20. [Dropped head syndrome as first manifestation of primary hyperparathyroid myopathy].

    Science.gov (United States)

    Ota, Kiyobumi; Koseki, Sayo; Ikegami, Kenji; Onishi, Iichiroh; Tomimitsu, Hiyoryuki; Shintani, Shuzo

    2018-03-28

    75 years old woman presented with 6-month history of progressive dropped head syndrome. Neurological examination revealed moderate weakness of flexor and extensor of neck and mild weakness of proximal appendicular muscles with normal deep tendon reflexes. The needle electromyography showed short duration and low amplitude motor unit potential. No fibrillation potentials or positive sharp waves were seen. Biopsy of deltoid muscle was normal. Laboratory studies showed elevated levels of serum calcium (11.8 mg/dl, upper limit of normal 10.1) and intact parathyroid hormone (104 pg/ml, upper limit of normal 65), and decreased level of serum phosphorus (2.3 mg/dl, lower limit of normal 2.7). Ultrasonography and enhanced computed tomography revealed a parathyroid tumor. The tumor was removed surgically. Pathological examination proved tumor to be parathyroid adenoma. Dropped head and weakness of muscles were dramatically improved within a week after the operation. Although hyperparathyroidism is a rare cause of dropped head syndrome, neurologists must recognize hyperparathyroidism as a treatable cause of dropped head syndrome.

  1. Drop test facility available to private industry

    International Nuclear Information System (INIS)

    Shappert, L.B.; Box, W.D.

    1983-01-01

    In 1978, a virtually unyielding drop test impact pad was constructed at Oak Ridge National Laboratory's (ORNL's) Tower Shielding Facility (TSF) for the testing of heavy shipping containers designed for transporting radioactive materials. Because of the facility's unique capability for drop-testing large, massive shipping packages, it has been identified as a facility which can be made available for non-DOE users

  2. University Drop-Out: An Italian Experience

    Science.gov (United States)

    Belloc, Filippo; Maruotti, Antonello; Petrella, Lea

    2010-01-01

    University students' drop-out is a crucial issue for the universities' efficiency evaluation and funding. In this paper, we analyze the drop-out rate of the Economics and Business faculty of Sapienza University of Rome. We use administrative data on 9,725 undergraduates students enrolled in three-years bachelor programs from 2001 to 2007 and…

  3. Total Site Heat Integration Considering Pressure Drops

    Directory of Open Access Journals (Sweden)

    Kew Hong Chew

    2015-02-01

    Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

  4. Why Do Students Drop Advanced Mathematics?

    Science.gov (United States)

    Horn, Ilana

    2004-01-01

    Students, especially black, Latino and Native American youth and students of low socio-economic status drop out of advanced mathematics. Teachers must coordinate their expectations, their knowledge of students and their teaching practices in order to stop struggling students from dropping out of advanced math classes.

  5. Wetting and evaporation of binary mixture drops.

    Science.gov (United States)

    Sefiane, Khellil; David, Samuel; Shanahan, Martin E R

    2008-09-11

    Experimental results on the wetting behavior of water, methanol, and binary mixture sessile drops on a smooth, polymer-coated substrate are reported. The wetting behavior of evaporating water/methanol drops was also studied in a water-saturated environment. Drop parameters (contact angle, shape, and volume) were monitored in time. The effects of the initial relative concentrations on subsequent evaporation and wetting dynamics were investigated. Physical mechanisms responsible for the various types of wetting behavior during different stages are proposed and discussed. Competition between evaporation and hydrodynamic flow are evoked. Using an environment saturated with water vapor allowed further exploration of the controlling mechanisms and underlying processes. Wetting stages attributed to differential evaporation of methanol were identified. Methanol, the more volatile component, evaporates predominantly in the initial stage. The data, however, suggest that a small proportion of methanol remained in the drop after the first stage of evaporation. This residual methanol within the drop seems to influence subsequent wetting behavior strongly.

  6. CPAS Preflight Drop Test Analysis Process

    Science.gov (United States)

    Englert, Megan E.; Bledsoe, Kristin J.; Romero, Leah M.

    2015-01-01

    Throughout the Capsule Parachute Assembly System (CPAS) drop test program, the CPAS Analysis Team has developed a simulation and analysis process to support drop test planning and execution. This process includes multiple phases focused on developing test simulations and communicating results to all groups involved in the drop test. CPAS Engineering Development Unit (EDU) series drop test planning begins with the development of a basic operational concept for each test. Trajectory simulation tools include the Flight Analysis and Simulation Tool (FAST) for single bodies, and the Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation for the mated vehicle. Results are communicated to the team at the Test Configuration Review (TCR) and Test Readiness Review (TRR), as well as at Analysis Integrated Product Team (IPT) meetings in earlier and intermediate phases of the pre-test planning. The ability to plan and communicate efficiently with rapidly changing objectives and tight schedule constraints is a necessity for safe and successful drop tests.

  7. Pressure drop in ET-RR-1

    International Nuclear Information System (INIS)

    Khattab, M.; Mina, A.R.

    1990-01-01

    Measurements of pressure drop through a bundle comprising 16 rods and their lower arrangement grid as well as orifices similar to those of ET-RR-1 core have been done. Experiments are carried out under adiabatic turbulent flow conditions at about 35 degree C. Bundle Reynolds number range is 4 x 10 -2 x 10. Orifices of diameters 4.5, 3.25 or 2.5 cm. are mounted underneath the bundle. The bundle and lower grid pressure drop coefficients are 3.75 and 1.8 respectively. Orifices pressure drop coefficients are 2.65, 19.67 and 53.55 respectively. The ratio of bundle pressure drop to that of 4.5 cm. Orifice diameter is 1.415. The pressure drop coefficients are utilizer to calculate flow through bundles. The flow rate per bundle is 39.1, 20.4 or 13.1 m 3 /hr. Depending on orifice diameter

  8. Basin-scale simulation of current and potential climate changed hydrologic conditions in the Lake Michigan Basin, United States

    Science.gov (United States)

    Christiansen, Daniel E.; Walker, John F.; Hunt, Randall J.

    2014-01-01

    The Great Lakes Restoration Initiative (GLRI) is the largest public investment in the Great Lakes in two decades. A task force of 11 Federal agencies developed an action plan to implement the initiative. The U.S. Department of the Interior was one of the 11 agencies that entered into an interagency agreement with the U.S. Environmental Protection Agency as part of the GLRI to complete scientific projects throughout the Great Lakes basin. The U.S. Geological Survey, a bureau within the Department of the Interior, is involved in the GLRI to provide scientific support to management decisions as well as measure progress of the Great Lakes basin restoration efforts. This report presents basin-scale simulated current and forecast climatic and hydrologic conditions in the Lake Michigan Basin. The forecasts were obtained by constructing and calibrating a Precipitation-Runoff Modeling System (PRMS) model of the Lake Michigan Basin; the PRMS model was calibrated using the parameter estimation and uncertainty analysis (PEST) software suite. The calibrated model was used to evaluate potential responses to climate change by using four simulated carbon emission scenarios from eight general circulation models released by the World Climate Research Programme’s Coupled Model Intercomparison Project phase 3. Statistically downscaled datasets of these scenarios were used to project hydrologic response for the Lake Michigan Basin. In general, most of the observation sites in the Lake Michigan Basin indicated slight increases in annual streamflow in response to future climate change scenarios. Monthly streamflows indicated a general shift from the current (2014) winter-storage/snowmelt-pulse system to a system with a more equally distributed hydrograph throughout the year. Simulated soil moisture within the basin illustrates that conditions within the basin are also expected to change on a monthly timescale. One effect of increasing air temperature as a result of the changing

  9. Water and Land Use Efficiency in Current and Potential Future US Corn and Brazilian Sugarcane Ethanol Systems

    Science.gov (United States)

    Warner, E. S.; Zhang, Y.; Newmark, R. L.

    2012-12-01

    Biofuels represent an opportunity for domestic fuel production from renewable energy sources with potential environmental and social benefits such as reducing greenhouse gas (GHG) and promoting rural development. However, as demand for biofuel continues to increase worldwide, concerns about land competition between food and fuel, excessive water usage and other unintended environmental consequences have grown. Through a comparative study between US corn ethanol and Brazilian sugarcane ethanol, we examine the energy, land, water and GHG performance of the two largest industrial fuel ethanol production systems in the world. Our comparisons include current and potential future systems with improved agronomic practices, crop yields, ethanol conversion processes, and utilization of agricultural residues. Our results suggest that the average water footprints of US corn ethanol and Brazilian sugarcane ethanol are fairly close (108 and 110 m3/GJ of ethanol, respectively) while the variations can range from 50 to 250 m3/GJ for sugarcane ethanol and 50 to380 m3/GJ for corn ethanol. Results emphasize the need to examine the water footprint within the context of local and regional climatic variability, water availability, competing uses (e.g. agricultural, industrial, and municipal water needs) and other ecosystem constraints. Research is under way (at the National Renewable Energy Laboratory and other institutions) to develop models to analyze water supply and demand at the watershed-scale for current and future biomass production, and to understand the tradeoffs among water supply, demand and quality due to more intensive agricultural practices and expansion of biofuels. Land use efficiency metrics, with regards to life cycle GHG emissions (without land use change) savings through gasoline displacement with ethanol, illustrate the progression of the biofuel industry and the importance of maximizing bioenergy production by utilizing both the crops and the residues. A recent

  10. Preventing preterm births: trends and potential reductions with current interventionsin 39 very high human development index countries

    Science.gov (United States)

    Chang, Hannah H.; Larson, Jim; Blencowe, Hannah; Spong, Catherine Y.; Howson, Christopher P.; Cairns-Smith, Sarah; Lackritz, Eve M.; Lee, Shoo K.; Mason, Elizabeth; Serazin, Andrew C.; Walani, Salimah; Simpson, Joe Leigh; Lawn, Joy E.

    2013-01-01

    Summary Background Each year,1.1 million babies die from prematurity, andmany survivors are disabled. Worldwide, 15 million babies are preterm(10,000 births, country-by-country analyses were performed based on target population, incremental coverage increase,and intervention efficacy. Cost savings were estimated based on reported costs for preterm care in the USAadjusted usingWorld Bank purchasing power parity. Findings From 2010, even if all VHHDI countries achieved annual preterm birth rate reductions of the best performers, (Sweden and Netherlands), 2000-2010 or 2005-2010(Lithuania, Estonia)), rates would experience a relative reduction of<5% by 2015 on average across the 39 countries.Our analysis of preterm birth rise 1998-2004 in USA suggests half the change is unexplained, but important drivers includeinductions/cesareandelivery and ART.For all 39 VHHDI countries, five interventionsmodeling at high coveragepredicted 5%preterm birth rate relative reduction from 9.59 to 9.07% of live births:smoking cessation (0.01 rate reduction), decreasing multiple embryo transfers during assisted reproductive technologies (0.06), cervical cerclage (0.15), progesterone supplementation (0.01), and reduction of non-medically indicated labour induction or caesarean delivery (0.29).These translate to 58,000 preterm births averted and total annual economic cost savings of ~US$ 3 billion. Interpretation Even with optimal coverage of current interventions, many being complex to implement, the estimated potential reduction in preterm birth is tiny. Hence we recommenda conservative target of 5% preterm birth rate relative reductionby 2015. Our findings highlight the urgent need for discovery research into underlying mechanisms of preterm birth, and developmentof innovative interventions. Furthermore, the highest preterm birth rates occur in low-income settings where the causes of prematurity may differand have simpler solutions, such as birth spacing and treatment of infections in

  11. Role of suppression of the inward rectifier current in terminal action potential repolarization in the failing heart.

    Science.gov (United States)

    Klein, Michael G; Shou, Matie; Stohlman, Jayna; Solhjoo, Soroosh; Haigney, Myles; Tidwell, Richard R; Goldstein, Robert E; Flagg, Thomas P; Haigney, Mark C

    2017-08-01

    The failing heart exhibits an increased arrhythmia susceptibility that is often attributed to action potential (AP) prolongation due to significant ion channel remodeling. The inwardly rectifying K + current (I K1 ) has been reported to be reduced, but its contribution to shaping the AP waveform and cell excitability in the failing heart remains unclear. The purpose of this study was to define the effect of I K1 suppression on the cardiac AP and excitability in the normal and failing hearts. We used electrophysiological and pharmacological approaches to investigate I K1 function in a swine tachy-pacing model of heart failure (HF). Terminal repolarization of the AP (TRAP; the time constant of the exponential fit to terminal repolarization) was markedly prolonged in both myocytes and arterially perfused wedges from animals with HF. TRAP was increased by 54.1% in HF myocytes (P < .001) and 26.2% in HF wedges (P = .014). The increase in TRAP was recapitulated by the potent and specific I K1 inhibitor, PA-6 (pentamidine analog 6), indicating that I K1 is the primary determinant of the final phase of repolarization. Moreover, we find that I K1 suppression reduced the ratio of effective refractory period to AP duration at 90% of repolarization, permitting re-excitation before full repolarization, reduction of AP upstroke velocity, and likely promotion of slow conduction. Using an objective measure of terminal repolarization, we conclude that I K1 is the major determinant of the terminal repolarization time course. Moreover, suppression of I K1 prolongs repolarization and reduces postrepolarization refractoriness without marked effects on the overall AP duration. Collectively, these findings demonstrate how I K1 suppression may contribute to arrhythmogenesis in the failing heart. Published by Elsevier Inc.

  12. Drop impact splashing and air entrapment

    KAUST Repository

    Thoraval, Marie-Jean

    2013-03-01

    Drop impact is a canonical problem in fluid mechanics, with numerous applications in industrial as well as natural phenomena. The extremely simple initial configuration of the experiment can produce a very large variety of fast and complex dynamics. Scientific progress was made in parallel with major improvements in imaging and computational technologies. Most recently, high-speed imaging video cameras have opened the exploration of new phenomena occurring at the micro-second scale, and parallel computing allowed realistic direct numerical simulations of drop impacts. We combine these tools to bring a new understanding of two fundamental aspects of drop impacts: splashing and air entrapment. The early dynamics of a drop impacting on a liquid pool at high velocity produces an ejecta sheet, emerging horizontally in the neck between the drop and the pool. We show how the interaction of this thin liquid sheet with the air, the drop or the pool, can produce micro-droplets and bubble rings. Then we detail how the breakup of the air film stretched between the drop and the pool for lower impact velocities can produce a myriad of micro-bubbles.

  13. Drop size measurements in Venturi scrubbers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Alonso, D.; Azzopardi, B.J. [Nottingham Univ. (United Kingdom). Dept. of Chemical Engineering; Goncalves, J.A.S.; Coury, J.R. [Universidade Federal de Sao Carlos (Brazil). Departamento de Engenharia Quimica

    2001-07-01

    Venturi scrubbers are high efficiency gas cleaners in which suspended particles are removed from gas streams by drops formed by liquid atomisation, usually in the Venturi throat. The size of the drops formed are of fundamental importance to the performance of the equipment, both in terms of pressure drop and dust removal efficiency. In this study, drop sizes in a cylindrical laboratory-scale Venturi scrubber were measured using a laser diffraction technique. Gas velocity and liquid to gas ratios varied from 50 to 90 m/s and 0.5 to 2.0 1/m{sup 3}, respectively. Water was injected using two different arrangements: either as jets in the throat or as a film just upstream of the convergence. Drop size measurements were performed at three positions in the case of jet injection: two located along the throat, and the last one at the end of the diffuser. The present data shows that the Sauter mean diameter of the spray can be well correlated by the equation of Boll et al. (J. Air Pollut. Control Assoc. 24 (1974) 932). Drop size distributions are satisfactorily represented by a Rosin-Rammler function. This paper also provides a simple method for calculating the parameters of the Rosin-Rammler function. As a result of this work, drop sizes in Venturi scrubbers can be estimated with much higher accuracy. (Author)

  14. "Self-Shaping" of Multicomponent Drops.

    Science.gov (United States)

    Cholakova, Diana; Valkova, Zhulieta; Tcholakova, Slavka; Denkov, Nikolai; Smoukov, Stoyan K

    2017-06-13

    In our recent study we showed that single-component emulsion drops, stabilized by proper surfactants, can spontaneously break symmetry and transform into various polygonal shapes during cooling [ Denkov Nature 2015 , 528 , 392 - 395 ]. This process involves the formation of a plastic rotator phase of self-assembled oil molecules beneath the drop surface. The plastic phase spontaneously forms a frame of plastic rods at the oil drop perimeter which supports the polygonal shapes. However, most of the common substances used in industry appear as mixtures of molecules rather than pure substances. Here we present a systematic study of the ability of multicomponent emulsion drops to deform upon cooling. The observed trends can be summarized as follows: (1) The general drop-shape evolution for multicomponent drops during cooling is the same as with single-component drops; however, some additional shapes are observed. (2) Preservation of the particle shape upon freezing is possible for alkane mixtures with chain length difference Δn ≤ 4; for greater Δn, phase separation within the droplet is observed. (3) Multicomponent particles prepared from alkanes with Δn ≤ 4 plastify upon cooling due to the formation of a bulk rotator phase within the particles. (4) If a compound, which cannot induce self-shaping when pure, is mixed with a certain amount of a compound which induces self-shaping, then drops prepared from this mixture can also self-shape upon cooling. (5) Self-emulsification phenomena are also observed for multicomponent drops. In addition to the three recently reported mechanisms of self-emulsification [ Tcholakova Nat. Commun. 2017 , ( 8 ), 15012 ], a new (fourth) mechanism is observed upon freezing for alkane mixtures with Δn > 4. It involves disintegration of the particles due to a phase separation of alkanes upon freezing.

  15. Thyrotoxicosis Presenting as Unilateral Drop Foot.

    Science.gov (United States)

    Hara, Kenju; Miyata, Hajime; Motegi, Takahide; Shibano, Ken; Ishiguro, Hideaki

    2017-01-01

    Neuromuscular disorders associated with hyperthyroidism have several variations in their clinical phenotype, such as ophthalmopathy, periodic paralysis, and thyrotoxic myopathy. We herein report an unusual case of thyrotoxic myopathy presenting as unilateral drop foot. Histopathological examinations of the left tibialis anterior muscle showed marked variation in the fiber size, mild inflammatory cell infiltration, and necrotic and regenerated muscle fibers with predominantly type 1 fiber atrophy. Medical treatment with propylthiouracil resulted in complete improvement of the left drop foot. This case expands the phenotype of thyrotoxicosis and suggests that thyrotoxicosis be considered as a possible cause of unilateral drop foot.

  16. Preparation and characterisation of superheated drop detectors

    International Nuclear Information System (INIS)

    Krishnamoorthy, P.

    1989-01-01

    Basic mechanism of bubble nucleation in superheated drops with respect to minimum energy of radiation and temperature is discussed. Experimental details and techniques for the preparation of Superheated Drop Detectors (SDDs) is explained. For the sample preparation, homogeneous composition of polymer (Morarfloc) and glycerine was used as the host medium and three different refrigerants Mafron-21, Mafron-12 and Mafron-11/12 (50:50) were chosen as the sensitive liquids. A pressure reactor developed at Health and Safety Laboratory is used for dispersing the sensitive liquid drops in the homogeneous composition under pressure. Some of the imporatant detector characteristics were studied. (author). 26 refs., 9 figs., 1 tab

  17. Molecular dynamics study of the vaporization of an ionic drop.

    Science.gov (United States)

    Galamba, N

    2010-09-28

    The melting of a microcrystal in vacuum and subsequent vaporization of a drop of NaCl were studied through molecular dynamics simulations with the Born-Mayer-Huggins-Tosi-Fumi rigid-ion effective potential. The vaporization was studied for a single isochor at increasing temperatures until the drop completely vaporized, and gaseous NaCl formed. Examination of the vapor composition shows that the vapor of the ionic drop and gaseous NaCl are composed of neutral species, the most abundant of which, ranging from simple NaCl monomers (ion pairs) to nonlinear polymers, (Na(n)Cl(n))(n=2-4). The enthalpies of sublimation, vaporization, and dissociation of the different vapor species are found to be in reasonable agreement with available experimental data. The decrease of the enthalpy of vaporization of the vapor species, with the radius of the drop decrease, accounts for a larger fraction of trimers and tetramers than that inferred from experiments. Further, the rhombic dimer is significantly more abundant than its linear isomer although the latter increases with the temperature. The present results suggest that both trimers and linear dimers may be important to explain the vapor pressure of molten NaCl at temperatures above 1500 K.

  18. Molecular dynamics study of the vaporization of an ionic drop

    Science.gov (United States)

    Galamba, N.

    2010-09-01

    The melting of a microcrystal in vacuum and subsequent vaporization of a drop of NaCl were studied through molecular dynamics simulations with the Born-Mayer-Huggins-Tosi-Fumi rigid-ion effective potential. The vaporization was studied for a single isochor at increasing temperatures until the drop completely vaporized, and gaseous NaCl formed. Examination of the vapor composition shows that the vapor of the ionic drop and gaseous NaCl are composed of neutral species, the most abundant of which, ranging from simple NaCl monomers (ion pairs) to nonlinear polymers, (NanCln)n=2-4. The enthalpies of sublimation, vaporization, and dissociation of the different vapor species are found to be in reasonable agreement with available experimental data. The decrease of the enthalpy of vaporization of the vapor species, with the radius of the drop decrease, accounts for a larger fraction of trimers and tetramers than that inferred from experiments. Further, the rhombic dimer is significantly more abundant than its linear isomer although the latter increases with the temperature. The present results suggest that both trimers and linear dimers may be important to explain the vapor pressure of molten NaCl at temperatures above 1500 K.

  19. Ultrasonic Substrate Vibration-Assisted Drop Casting (SVADC) for the Fabrication of Photovoltaic Solar Cell Arrays and Thin-Film Devices.

    Science.gov (United States)

    Eslamian, Morteza; Zabihi, Fatemeh

    2015-12-01

    A simple, low-cost, versatile, and potentially scalable casting method is proposed for the fabrication of micro- and nano-thin films, herein termed as ultrasonic "substrate vibration-assisted drop casting" (SVADC). The impingement of a solution drop onto a substrate in a simple process called drop casting, usually results in spreading of the liquid solution and the formation of a non-uniform thin solid film after solvent evaporation. Our previous and current supporting results, as well as few similar reports by others, confirm that imposing ultrasonic vibration on the substrate can simply convert the uncontrollable drop casting method into a controllable coating technique. Therefore, the SVADC may be used to fabricate an array of emerging thin-film solar cells, such as polymer, perovskite, and quantum-dot solar cells, as well as other small thin-film devices, in a roll-to-roll and automated fabrication process. The preliminary results demonstrate a ten-fold increase in electrical conductivity of PSS made by SVADC compared with the film made by conventional drop casting. Also, simple planar perovskite solar cells made here using SVADC show promising performance with an efficiency of over 3 % for a simple structure without performing process optimization or using expensive materials and treatments.

  20. Combining spray nozzle simulators with meshes: characterization of rainfall intensity and drop properties

    Science.gov (United States)

    Carvalho, Sílvia C. P.; de Lima, João L. M. P.; de Lima, M. Isabel P.

    2013-04-01

    Rainfall simulators can be a powerful tool to increase our understanding of hydrological and geomorphological processes. Nevertheless, rainfall simulators' design and operation might be rather demanding, for achieving specific rainfall intensity distributions and drop characteristics. The pressurized simulators have some advantages over the non-pressurized simulators: drops do not rely on gravity to reach terminal velocity, but are sprayed out under pressure; pressurized simulators also yield a broad range of drop sizes in comparison with drop-formers simulators. The main purpose of this study was to explore in the laboratory the potential of combining spray nozzle simulators with meshes in order to change rainfall characteristics (rainfall intensity and diameters and fall speed of drops). Different types of spray nozzles were tested, such as single full-cone and multiple full-cone nozzles. The impact of the meshes on the simulated rain was studied by testing different materials (i.e. plastic and steel meshes), square apertures and wire thicknesses, and different vertical distances between the nozzle and the meshes underneath. The diameter and fall speed of the rain drops were measured using a Laser Precipitation Monitor (Thies Clima). The rainfall intensity range and coefficients of uniformity of the sprays and the drop size distribution, fall speed and kinetic energy were analysed. Results show that when meshes intercept drop trajectories the spatial distribution of rainfall intensity and the drop size distribution are affected. As the spray nozzles generate typically small drop sizes and narrow drop size distributions, meshes can be used to promote the formation of bigger drops and random their landing positions.

  1. The human ether-a-go-go-related gene (hERG) current inhibition selectively prolongs action potential of midmyocardial cells to augment transmural dispersion.

    Science.gov (United States)

    Yasuda, C; Yasuda, S; Yamashita, H; Okada, J; Hisada, T; Sugiura, S

    2015-08-01

    The majority of drug induced arrhythmias are related to the prolongation of action potential duration following inhibition of rapidly activating delayed rectifier potassium current (I(Kr)) mediated by the hERG channel. However, for arrhythmias to develop and be sustained, not only the prolongation of action potential duration but also its transmural dispersion are required. Herein, we evaluated the effect of hERG inhibition on transmural dispersion of action potential duration using the action potential clamp technique that combined an in silico myocyte model with the actual I(Kr) measurement. Whole cell I(Kr) current was measured in Chinese hamster ovary cells stably expressing the hERG channel. The measured current was coupled with models of ventricular endocardial, M-, and epicardial cells to calculate the action potentials. Action potentials were evaluated under control condition and in the presence of 1, 10, or 100 μM disopyramide, an hERG inhibitor. Disopyramide dose-dependently increased the action potential durations of the three cell types. However, action potential duration of M-cells increased disproportionately at higher doses, and was significantly different from that of epicardial and endocardial cells (dispersion of repolarization). By contrast, the effects of disopyramide on peak I(Kr) and instantaneous current-voltage relation were similar in all cell types. Simulation study suggested that the reduced repolarization reserve of M-cell with smaller amount of slowly activating delayed rectifier potassium current levels off at longer action potential duration to make such differences. The action potential clamp technique is useful for studying the mechanism of arrhythmogenesis by hERG inhibition through the transmural dispersion of repolarization.

  2. An Analysis of Current Energy Policy Initiatives in New Mexico. What are the Potential Impacts to the State's Water Resources?

    Science.gov (United States)

    Klise, G. T.; Hart, W. E.; Kobos, P. H.; Malczynski, L. A.; Tidwell, V. C.

    2008-12-01

    Population in New Mexico is increasing rapidly with recent projections showing that the state will add more than 1 million people by 2035. This growth will create a demand for additional energy and water supplies that have yet to be developed. New Mexico currently exports about 50% of the energy generated within the state to neighboring states, and existing power plants predominately utilize traditional fossil fuels such as coal, oil and natural gas. Because traditional electric generation technologies utilize large quantities of water, New Mexico can also be seen as exporting water for the benefit of electricity consumed in neighboring states. As it is, both surface water and groundwater supplies are stretched thin and these internal and external stresses stemming from population growth will have a substantial impact on the state's water resources. In 2004, the Governor laid out a plan to make New Mexico a "Clean Energy State" by implementing renewable portfolio standards, developing renewable energy transmission infrastructure, creating an alternative energy innovation fund and creating state specific tax credits for renewable energy production and manufacturing. Recent work in the National Energy-Water Roadmap has pointed out that certain renewable sources of energy utilize less water than traditional power plants, and technological fixes to existing power plants will result in less water consumption. If New Mexico carries out its energy initiative, what will be the impacts to the state's water resources? Will it be possible to meet competing demands for this water? These questions and others will be analyzed in a decision-support tool that can look at the connection between both the physical and economic systems to see what the tradeoffs might be as a result of specific policy decisions. The ability to plan for future energy needs and understanding potential impacts to the state's limited water resources will be an invaluable tool for decision-makers in New

  3. Transient Receptor Potential Vanilloid 4 Activation-Induced Increase in Glycine-Activated Current in Mouse Hippocampal Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Mengwen Qi

    2018-02-01

    Full Text Available Background/Aims: Glycine plays an important role in regulating hippocampal inhibitory/ excitatory neurotransmission through activating glycine receptors (GlyRs and acting as a co-agonist of N-methyl-d-aspartate-type glutamate receptors. Activation of transient receptor potential vanilloid 4 (TRPV4 is reported to inhibit hippocampal A-type γ-aminobutyric acid receptor, a ligand-gated chloride ion channel. GlyRs are also ligand-gated chloride ion channels and this paper aimed to explore whether activation of TRPV4 could modulate GlyRs. Methods: Whole-cell patch clamp recording was employed to record glycine-activated current (IGly and Western blot was conducted to assess GlyRs subunits protein expression. Results: Application of TRPV4 agonist (GSK1016790A or 5,6-EET increased IGly in mouse hippocampal CA1 pyramidal neurons. This action was blocked by specific antagonists of TRPV4 (RN-1734 or HC-067047 and GlyR (strychnine, indicating that activation of TRPV4 increases strychnine-sensitive GlyR function in mouse hippocampal pyramidal neurons. GSK1016790A-induced increase in IGly was significantly attenuated by protein kinase C (PKC (BIM II or D-sphingosine or calcium/calmodulin-dependent protein kinase II (CaMKII (KN-62 or KN-93 antagonists but was unaffected by protein kinase A or protein tyrosine kinase antagonists. Finally, hippocampal protein levels of GlyR α1 α2, α3 and β subunits were not changed by treatment with GSK1016790A for 30 min or 1 h, but GlyR α2, α3 and β subunits protein levels increased in mice that were intracerebroventricularly (icv. injected with GSK1016790A for 5 d. Conclusion: Activation of TRPV4 increases GlyR function and expression, and PKC and CaMKII signaling pathways are involved in TRPV4 activation-induced increase in IGly. This study indicates that GlyRs may be effective targets for TRPV4-induced modulation of hippocampal inhibitory neurotransmission.

  4. What's down below? Current and potential future applications of geophysical techniques to identify subsurface permafrost conditions (Invited)

    Science.gov (United States)

    Douglas, T. A.; Bjella, K.; Campbell, S. W.

    2013-12-01

    For infrastructure design, operations, and maintenance requirements in the North the ability to accurately and efficiently detect the presence (or absence) of ground ice in permafrost terrains is a serious challenge. Ground ice features including ice wedges, thermokarst cave-ice, and segregation ice are present in a variety of spatial scales and patterns. Currently, most engineering applications use borehole logging and sampling to extrapolate conditions at the point scale. However, there is high risk of over or under estimating the presence of frozen or unfrozen features when relying on borehole information alone. In addition, boreholes are costly, especially for planning linear structures like roads or runways. Predicted climate warming will provide further challenges for infrastructure development and transportation operations where permafrost degradation occurs. Accurately identifying the subsurface character in permafrost terrains will allow engineers and planners to cost effectively create novel infrastructure designs to withstand the changing environment. There is thus a great need for a low cost rapidly deployable, spatially extensive means of 'measuring' subsurface conditions. Geophysical measurements, both terrestrial and airborne, have strong potential to revolutionize our way of mapping subsurface conditions. Many studies in continuous and discontinuous permafrost have used geophysical measurements to identify discrete features and repeatable patterns in the subsurface. The most common measurements include galvanic and capacitive coupled resistivity, ground penetrating radar, and multi frequency electromagnetic induction techniques. Each of these measurements has strengths, weaknesses, and limitations. By combining horizontal geophysical measurements, downhole geophysics, multispectral remote sensing images, LiDAR measurements, and soil and vegetation mapping we can start to assemble a holistic view of how surface conditions and standoff measurements

  5. Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

    Directory of Open Access Journals (Sweden)

    Ye Zhang

    2017-11-01

    Full Text Available BackgroundThe electrophysiological evidence supporting the therapeutic efficacy of multiple transcranial direct current stimulation (tDCS sessions on consciousness improvement in patients with prolonged disorders of consciousness (DOCs has not been firmly established.ObjectivesTo assess the effects of repeated tDCS in patients with prolonged DOCs by Coma Recovery Scale-Revised (CRS-R score and event-related potential (ERP.MethodUsing a sham-controlled randomized double-blind design, 26 patients were randomly assigned to either a real [five vegetative state (VS and eight minimally conscious state (MCS patients] or sham (six VS and seven MCS patients stimulation group. The patients in the real stimulation group underwent 20 anodal tDCS sessions of the left dorsolateral prefrontal cortex (DLPFC over 10 consecutive working days. The CRS-R score and P300 amplitude and latency in a hierarchical cognitive assessment were recorded to evaluate the consciousness level before tDCS and immediately after the 20 sessions.ResultsThe intra-group CRS-R analysis revealed a clinically significant improvement in the MCS patients in the real stimulation group. The inter-group CRS-R analysis showed a significant difference in CRS-R between VS and MCS patients at baseline in both the real and sham stimulation groups. The intra-group ERP analysis revealed a significant increase in P300 amplitude after tDCS in the MCS patients in the real stimulation group, but no significant differences in P300 latency. For the inter-group ERP analysis, we observed significant differences regarding the presence of P300 at baseline between the VS and MCS patients in both groups.ConclusionThe repeated anodal tDCS of the left DLPFC could produce clinically significant improvements in MCS patients. The observed tDCS-related consciousness improvements might be related to improvements in attention resource allocation (reflected by the P300 amplitude. The findings support the use of tDCS in

  6. Economic benefits of high value medicinal plants to Pakistani communities: an analysis of current practice and potential.

    Science.gov (United States)

    Sher, Hassan; Aldosari, Ali; Ali, Ahmad; de Boer, Hugo J

    2014-10-10

    Poverty is pervasive in the Swat Valley, Pakistan. Most of the people survive by farming small landholdings. Many earn additional income by collecting and selling plant material for use in herbal medicine. This material is collected from wild populations but the people involved have little appreciation of the potential value of the plant material they collect and the long term impact their collecting has on local plant populations. In 2012, existing practices in collecting and trading high value minor crops from Swat District, Pakistan, were analyzed. The focus of the study was on the collection pattern of medicinal plants as an economic activity within Swat District and the likely destinations of these products in national or international markets. Local collectors/farmers and dealers were surveyed about their collection efforts, quantities collected, prices received, and resulting incomes. Herbal markets in major cities of Pakistan were surveyed for current market trends, domestic sources of supply, imports and exports of herbal material, price patterns, and market product-quality requirements. It was observed that wild collection is almost the only source of medicinal plant raw material in the country, with virtually no cultivation. Gathering is mostly done by women and children of nomadic Middle Hill tribes who earn supplementary income through this activity, with the plants then brought into the market by collectors who are usually local farmers. The individuals involved in gathering and collecting are largely untrained regarding the pre-harvest and post-harvest treatment of collected material. Most of the collected material is sold to local middlemen. After that, the trade pattern is complex and heterogeneous, involving many players. Pakistan exports of high value plants generate over US$10.5 million annually in 2012, with a substantial percentage of the supply coming from Swat District, but its market share has been declining. Reasons for the decline were

  7. A novel bioenergy feedstock in Latin America? Cultivation potential of Acrocomia aculeata under current and future climate conditions

    NARCIS (Netherlands)

    Plath, Mirco; Moser, Christine; Bailis, Rob; Brandt, Patric; Hirsch, Heidi; Klein, Alexandra Maria; Walmsley, David; Wehrden, von Henrik

    2016-01-01

    Plant oil is a key commodity in the global economy, particularly for food and bioenergy markets. However, current production practices often impair smallholder livelihoods, cause land use changes, and compete for food production. The neotropical palm Acrocomia aculeata is currently being promoted

  8. Micro-splashing by drop impacts

    KAUST Repository

    Thoroddsen, Sigurdur T; Takehara, Kohsei; Etoh, Takeharugoji

    2012-01-01

    We use ultra-high-speed video imaging to observe directly the earliest onset of prompt splashing when a drop impacts onto a smooth solid surface. We capture the start of the ejecta sheet travelling along the solid substrate and show how it breaks up immediately upon emergence from the underneath the drop. The resulting micro-droplets are much smaller and faster than previously reported and may have gone unobserved owing to their very small size and rapid ejection velocities, which approach 100 m s-1, for typical impact conditions of large rain drops. We propose a phenomenological mechanism which predicts the velocity and size distribution of the resulting microdroplets. We also observe azimuthal undulations which may help promote the earliest breakup of the ejecta. This instability occurs in the cusp in the free surface where the drop surface meets the radially ejected liquid sheet. © 2012 Cambridge University Press.

  9. Micro-splashing by drop impacts

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2012-07-18

    We use ultra-high-speed video imaging to observe directly the earliest onset of prompt splashing when a drop impacts onto a smooth solid surface. We capture the start of the ejecta sheet travelling along the solid substrate and show how it breaks up immediately upon emergence from the underneath the drop. The resulting micro-droplets are much smaller and faster than previously reported and may have gone unobserved owing to their very small size and rapid ejection velocities, which approach 100 m s-1, for typical impact conditions of large rain drops. We propose a phenomenological mechanism which predicts the velocity and size distribution of the resulting microdroplets. We also observe azimuthal undulations which may help promote the earliest breakup of the ejecta. This instability occurs in the cusp in the free surface where the drop surface meets the radially ejected liquid sheet. © 2012 Cambridge University Press.

  10. A cross-sectional study of the actual use of eye drops in a Saudi ...

    African Journals Online (AJOL)

    and storage of eye drops, and the participants' understanding of the role of pharmacist in enhancing ... This is an Open Access article that uses a funding model which does not charge readers .... to minimise the risks and optimise the potential.

  11. Pressure drop in flashing flow through obstructions

    International Nuclear Information System (INIS)

    Weinle, M.E.; Johnston, B.S.

    1985-01-01

    An experiment was designed to investigate the pressure drop for flashing flow across obstructions of different geometries at various flow rates. Tests were run using two different orifices to determine if the two-phase pressure drop could be characterized by the single phase loss coefficient and the general behavior of the two-phase multiplier. For the geometries studied, it was possible to correlate the multiplier in a geometry-independent fashion

  12. Pressure drop in T's in concentric ducts

    International Nuclear Information System (INIS)

    Shock, R.A.W.

    1983-02-01

    A set of experiments has been carried out to measure the pressure drop characteristics of single-phase flow in dividing and joining right-angled T's in a concentric ducting system. These have been compared with measured pressure drops in a simple round tube system. In most tests with the concentric system the number of velocity heads lost is either similar to, or more than, the value for the round tubes. (author)

  13. Increased sensitivity of anodic stripping voltammetry at the hanging mercury drop electrode by ultracathodic deposition.

    Science.gov (United States)

    Rodrigues, José A; Rodrigues, Carlos M; Almeida, Paulo J; Valente, Inês M; Gonçalves, Luís M; Compton, Richard G; Barros, Aquiles A

    2011-09-09

    An improved approach to the anodic stripping voltammetric (ASV) determination of heavy metals, using the hanging mercury drop electrode (HMDE), is reported. It was discovered that using very cathodic accumulation potentials, at which the solvent reduction occurs (overpotential deposition), the voltammetric signals of zinc(II), cadmium(II), lead(II) and copper(II) increase. When compared with the classical methodology a 5 to 10-fold signal increase is obtained. This effect is likely due to both mercury drop oscillation at such cathodic potentials and added local convection at the mercury drop surface caused by the evolution of hydrogen bubbles. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Static aspects of the fission and fusion of liquid 3He drops

    International Nuclear Information System (INIS)

    Guilleumas, M.; Barranco, M.; Pi, M.

    1992-01-01

    Using an effective 3 He- 3 He interaction, the fission and fusion of 3 He drops have been investigated from a static point of view. The calculations show that a fission barrier develops for these neutral systems, and that their saddle configurations are rather elongate. The transition from oblate to prolate shapes as a function of the angular momentum L, as well as critical values for fission and fusion are discussed for some selected cases. A kind of proximity potential can be extracted from the drop-drop interaction potentials. (author) 33 refs.; 9 figs

  15. Hanging drop crystal growth apparatus and method

    Science.gov (United States)

    Carter, Daniel C. (Inventor); Smith, Robbie E. (Inventor)

    1989-01-01

    An apparatus (10) is constructed having a cylindrical enclosure (16) within which a disc-shaped wicking element (18) is positioned. A well or recess (22) is cut into an upper side (24) of this wicking element, and a glass cover plate or slip (28) having a protein drop disposed thereon is sealably positioned on the wicking element (18), with drop (12) being positioned over well or recess (22). A flow of control fluid is generated by a programmable gradient former (16), with this control fluid having a vapor pressure that is selectively variable. This flow of control fluid is coupled to the wicking element (18) where control fluid vapor diffusing from walls (26) of the recess (22) is exposed to the drop (12), forming a vapor pressure gradient between the drop (12) and the control fluid vapor. Initially, this gradient is adjusted to draw solvent from the drop (12) at a relatively high rate, and as the critical supersaturation point is approached (the point at which crystal nucleation occurs), the gradient is reduced to more slowly draw solvent from the drop (12). This allows discrete protein molecules more time to orient themselves into an ordered crystalline lattice, producing protein crystals which, when processed by X-ray crystallography, possess a high degree of resolution.

  16. Drop Performance Test of CRDMs for JRTR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Myoung-Hwan; Cho, Yeong-Garp; Chung, Jong-Ha [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jung-Hyun [POSCO Plandtec Co. Ltd, Ulsan (Korea, Republic of); Lee, Kwan-Hee [RIST, Pohang (Korea, Republic of)

    2015-10-15

    The drop test results of CRDMs with AC-type electromagnet show that the initial delay times are not satisfied with the requirement, 0.15 seconds. After the replacement of the electromagnet from AC-type to DCtype, the drop times of CARs and accelerations due to the impact of moving parts are satisfied with all requirements. As a result, it is found that four CRDMs to be installed at site have a good drop performance, and meet all performance requirements. A control rod drive mechanism (CRDM) is a device to control the position of a control absorber rod (CAR) in the core by using a stepping motor which is commanded by the reactor regulating system (RRS) to control the reactivity during the normal operation of the reactor. The top-mounted CRDM driven by the stepping motor for Jordan Research and Training Reactor (JRTR) has been developed in KAERI. The CRDM for JRTR has been optimized by the design improvement based on that of the HANARO. It is necessary to verify the performances such as the stepping, drop, endurance, vibration, seismic and structural integrity for active components. Especially, the CAR drop curves are important data for the safety analysis. This paper describes the test results to demonstrate the drop performances of a prototype and 4 CRDMs to be installed at site. The tests are carried out at a test rig simulating the actual reactor's conditions.

  17. Study of complex resistivity measurement using current and potential waveform data; Denryu to den`i hakei data wo riyoshita fukusohi teiko sokutei no kento

    Energy Technology Data Exchange (ETDEWEB)

    Shima, H; Sakurai, K; Yamashita, Y [OYO Corp., Tokyo (Japan)

    1997-10-22

    This paper proposes a measurement method for complex resistivity using both current and potential waveforms. This method was applied to actual data. Especially, chargeability was discussed among complex resistivities. A method was proposed for determining the complex resistivity. At first, digital measurements of both current and potential waveforms were conducted. For the potential waveform, zero-order self-potential was canceled. Then, the FFT technique was applied to both current and potential waveforms, to determine both current and potential in the frequency domain. Hereafter, complex resistivity was determined through simple division. Since the inductive coupling was observed at higher frequencies, it was difficult to apply Cole-Cole model, simply. However, the inductive coupling could be removed using proper sampling frequency. Thus, a proper Cole-Cole dispersion curve could be obtained. Using this Cole-Cole dispersion curve, new chargeability could be defined. A linear relation between this chargeability and the ordinary time domain chargeability was made clear. 4 refs., 10 figs.

  18. Development of Drop/Shock Test in Microelectronics and Impact Dynamic Analysis for Uniform Board Response

    Science.gov (United States)

    Kallolimath, Sharan Chandrashekar

    -joints. No ring test conditions was proposed and verified for the current widely used JEDEC standard. The significance of impact loading parameters such as pulse magnitude, pulse duration, pulse shapes and board dynamic parameter such as linear hysteretic damping and dynamic stiffness were discussed. Third, Kirchhoff's plate theory by principle of minimum potential energy was adopted to develop the FEA formulation to consider the effect of material hysteretic damping for the currently used JEDEC board test and proposed no-ring response test condition. Fourth, a hexagonal symmetrical board model was proposed to address the uniform stress and strain distribution throughout the test board and identify the critical failure factors. Dynamic stress and strain of the hexagonal board model were then compared with standard JEDEC board for both standard and proposed no-ring test conditions. In general, this line of research demonstrates that advanced techniques of FEA analysis can provide useful insights concerning the optimal design of drop test in microelectronics.

  19. Development of Active Learning Curriculum for CASPER's Microgravity Drop Tower

    Science.gov (United States)

    Carmona-Reyes, Jorge; Wang, Li; York, Judy; Matthews, Lorin; Laufer, Rene; Cook, Mike; Schmoke, Jimmy; Hyde, Truell

    2016-10-01

    As CASPER's new drop tower comes on line, plans for correlated educational research curricula are underway. CASPER's educational research team is working on developing curricula specific to the CASPER drop tower, modeled on a contest currently in use by (BEST) Robotics Inc. within central Texas independent school districts. The curricula integrates age specific use of computer programming software packages such as ``Scratch'' with industry standard communication protocols and augmented reality applications. Content is constructed around an earth and space science framework, covering subjects such as stars and galaxies, matter and energy, fusion and fission at a middle school level. CASPER faculty are partnering with the Region 12 Service Center; this combination provides a wide range of expertise that includes professional development, pedagogical methods, computational thinking in addition to microgravity and space science research expertise. The details of this work will be presented and samples of the manner in which it is impacting the CASPER research and educational outreach partnership will be discussed.

  20. The formation of intestinal organoids in a hanging drop culture.

    Science.gov (United States)

    Panek, Malgorzata; Grabacka, Maja; Pierzchalska, Malgorzata

    2018-01-25

    Recently organoids have become widely used in vitro models of many tissue and organs. These type of structures, originated from embryonic or adult mammalian intestines, are called "mini guts". They organize spontaneously when intestinal crypts or stem cells are embedded in the extracellular matrix proteins preparation scaffold (Matrigel). This approach has some disadvantages, as Matrigel is undefined (the concentrations of growth factors and other biologically active components in it may vary from batch to batch), difficult to handle and expensive. Here we show that the organoids derived from chicken embryo intestine are formed in a hanging drop without embedding, providing an attractive alternative for currently used protocols. Using this technique we obtained compact structures composed of contiguous organoids, which were generally similar to chicken organoids cultured in Matrigel in terms of morphology and expression of intestinal epithelial markers. Due to the simplicity, high reproducibility and throughput capacity of hanging drop technique our model may be applied in various studies concerning the gut biology.