WorldWideScience

Sample records for medium frequency

  1. Generation of medium frequency electrotherapeutic signals

    Science.gov (United States)

    Płaza, Mirosław; Szcześniak, Zbigniew; Dudek, Jolanta

    2017-08-01

    In this paper, generation methods of sinusoidal medium frequency electrotherapeutic signals have been studied. Signals of this type are increasingly used in electrotherapy owing to the development of both physical medicine and engineering sciences. The article presents analysis and comparison of analogue and digital methods of generation therapeutic signals. Analysis presented in the paper attempts to answer the question which technique of medium frequency signal generation can be most broadly applied in electrotherapy methods.

  2. The frequency characteristics of medium voltage distribution system impedances

    Directory of Open Access Journals (Sweden)

    Liviu Emil Petrean

    2009-10-01

    Full Text Available In this paper we present the frequency characteristics of impedances involved in the electrical equivalent circuit of a large medium voltage distribution system. These impedances influence harmonics distortions propagation occurring due to the nonsinusoidal loads. We analyse the case of a 10 kV large urban distribution system which supplies industrial, commercial and residential customers. The influence of various parameters of the distribution network on the frequency characteristics are presented, in order to assess the interaction of harmonic distortion and distribution system network.

  3. Frequency selective bistable switching in metamaterial based photonic bandgap medium

    Science.gov (United States)

    Jose, Jolly

    2014-10-01

    We present frequency selective bistable response at the defect mode of the zero-nbar bandgap of a photonic bandgap (PBG) material made of negative and positive index media. The nonlinear (Kerr) layer acts as the defect layer in the periodic PBG material. Incorporating metamaterial based electromagnetically induced transparency (EIT) like resonance in the positive layer leads to unprecedented line narrowing of the defect mode which in turn facilitates narrow frequency selective bistable operation, wherein all the bistable characteristics can be effectively engineered. Thresholding the output intensity selects the narrow band of frequencies that exhibit bistability.

  4. Muscle force production with low and medium frequency burst modulated biphasic pulsed currents.

    Science.gov (United States)

    Bellew, James W; Sanders, Kyle; Schuman, Kristen; Barton, Matt

    2014-02-01

    Russian current, a medium frequency burst modulated alternating current (BMAC), is widely used for NMES, but has not been shown to elicit forces near voluntary maximum. In contrast, low frequency BMAC has been shown to produce greater force production than Russian and most recently, medium frequency burst modulated biphasic pulsed current (BMBPC) elicited greater force than Russian. Whether low frequency BMBPC yields greater force than medium frequency BMBPC is unknown. This study examined elicited forces using BMBPC with low and medium frequency carrier currents. A cross-over design where percent maximal isometric knee extensor forces (%MVIF) elicited using BMBPC with low or medium kilohertz carrier frequencies were compared in 23 subjects. Perceived discomfort was also assessed. Data were compared using paired samples t-tests. 98.4% of the MVIF was elicited with the low frequency BMBPC which was significantly greater (p current. Cohen's d effect size of 2.146 indicated a "huge effect". Perceived discomfort of the low frequency current was 5.7/10 and was significantly greater (p current (3.6/10). BMBPC with low frequency carrier current elicits forces approximating maximal volitional force. These findings offer new evidence with strong clinical implications when using NMES.

  5. Application of Low Frequency and Medium Frequency Currents in the Management of Acute and Chronic Pain-A Narrative Review

    OpenAIRE

    Samuel, Stephen Rajan; Maiya, G Arun

    2015-01-01

    Trancutaneous electrical nerve stimulation (TENS) and interferential therapy (IFT) have been a regular line of treatment for various types of acute and chronic pain. This review aims to compile the latest literature in pain management using these modalities which use low-frequency and medium-frequency currents. The Cochrane Library, Scopus, PubMed, MEDLINE, and CINAHL were searched and studies were examined from their inception till October 2013. After title and abstract screening the relevan...

  6. State of art survey for design of medium frequency high power transformer

    DEFF Research Database (Denmark)

    Vaisambhayana, Sriram; Dincan, Catalin; Shuyu, Cao

    2016-01-01

    Medium and high frequency, high power transformers play an important role in footprint reduction along with their functions of galvanic isolation, and voltage transformation in all high power converters typically used in traction power systems, offshore wind plant power converters, and solid state...... transformer based distribution system grids. This state of art report analysis the various materials and design tradeoffs that govern the electromagnetic behavior and loss mechanisms of the medium frequency transformer applications. Typical winding and core geometries that have been reported extensively...

  7. Populations of striatal medium spiny neurons encode vibrotactile frequency in rats: modulation by slow wave oscillations.

    Science.gov (United States)

    Hawking, Thomas G; Gerdjikov, Todor V

    2013-01-01

    Dorsolateral striatum (DLS) is implicated in tactile perception and receives strong projections from somatosensory cortex. However, the sensory representations encoded by striatal projection neurons are not well understood. Here we characterized the contribution of DLS to the encoding of vibrotactile information in rats by assessing striatal responses to precise frequency stimuli delivered to a single vibrissa. We applied stimuli in a frequency range (45-90 Hz) that evokes discriminable percepts and carries most of the power of vibrissa vibration elicited by a range of complex fine textures. Both medium spiny neurons and evoked potentials showed tactile responses that were modulated by slow wave oscillations. Furthermore, medium spiny neuron population responses represented stimulus frequency on par with previously reported behavioral benchmarks. Our results suggest that striatum encodes frequency information of vibrotactile stimuli which is dynamically modulated by ongoing brain state.

  8. Time-domain electromagnetic energy in a frequency-dispersive left-handed medium

    International Nuclear Information System (INIS)

    Cui Tiejun; Kong Jinau

    2004-01-01

    From Maxwell's equations and the Poynting theorem, the time-domain electric and magnetic energy densities are generally defined in the frequency-dispersive media based on the conservation of energy. As a consequence, a general definition of electric and magnetic energy is proposed. Comparing with existing formulations of electric and magnetic energy in frequency-dispersive media, the new definition is more reasonable and is valid in any case. Using the new definition and staring from the equation of motion, we have shown rigorously that the total energy density and the individual electric and magnetic energy densities are always positive in a realistic artificial left-handed medium (LHM) [R. A. Shelby, D. R. Smith, and S. Schultz, Science 292, 77 (2001)], which obeys actually the Lorentz medium model, although such a LHM has negative permittivity and negative permeability simultaneously in a certain frequency range. We have also shown that the conservation of energy is not violated in LHM. The earlier conclusions can be easily extended to the Drude medium model and the cold plasma medium model. Through an exact analysis of a one-dimensional transient current source radiating in LHM, numerical results are given to demonstrate that the work done by source, the power flowing outwards a surface, and the electric and magnetic energy stored in a volume are all positive in the time domain

  9. Effects of the interstellar medium on detection of low-frequency gravitational waves

    International Nuclear Information System (INIS)

    Stinebring, Dan

    2013-01-01

    Time variable delays due to radio wave propagation in the ionized interstellar medium are a substantial source of error in pulsar timing array efforts. We describe the physical origin of these effects, discussing dispersive and scattering effects separately. Where possible, we give estimates of the magnitude of timing errors produced by these effects and their scaling with radio frequency. Although there is general understanding of the interstellar medium propagation errors to be expected with pulsar timing array observations, detailed comparison between theory and practice is still in its infancy, particularly with regard to scattering effects. (paper)

  10. Frequency-domain modelling of gain in pump-probe experiment by an inhomogeneous medium

    Science.gov (United States)

    Kim, Minkyung; Oh, Sang Soon; Hess, Ortwin; Rho, Junsuk

    2018-02-01

    Introduction of a gain medium in lossy plasmonic metamaterials reduces and compensates losses or even amplifies an incident light often with nonlinear optical effect. Here, optical gain in a pump-probe experimental setup is effectively calculated in the frequency-domain by approximating a gain material as an inhomogeneous medium. Spatially varying local field amplitudes of the pump and probe beams are included in the model to reproduce the inhomogeneous gain effect, in which population inversion occurs most strongly near the surface and decays along the propagation direction. We demonstrate that transmission spectra calculated by this method agree well with finite-difference time-domain simulation results. This simplified approach of gain modelling offers an easy and reliable way to analyze wave propagation in a gain medium without nonlinear time-domain calculation.

  11. Frequency stabilization of multiple lasers on a single medium-finesse cavity

    Science.gov (United States)

    Han, Chengyin; Zhou, Min; Gao, Qi; Li, Shangyan; Zhang, Shuang; Qiao, Hao; Ai, Di; Zhang, Mengya; Lou, Ge; Luo, Limeng; Xu, Xinye

    2018-04-01

    We present a simple, compact, and robust frequency stabilization system of three lasers operating at 649, 759, and 770 nm, respectively. These lasers are applied in experiments on ytterbium optical lattice clocks, for which each laser needs to have a linewidth of a few hundred or tens of kilohertz while maintaining a favorable long-term stability. Here, a single medium-finesse cavity is adopted as the frequency reference and the standard Pound-Drever-Hall technique is used to stabilize the laser frequencies. Based on the independent phase modulation, multiple-laser locking is demonstrated without mutual intervention. The locked lasers are measured to have a linewidth of 100 kHz and the residual frequency drift is about 78.5 Hz s-1. This kind of setup provides a construction that is much simpler than that in previous work.

  12. Low-frequency asymptotic analysis of seismic reflection from afluid-saturated medium

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.B.; Korneev, V.A.; Goloshubin, G.M.; Patzek, T.W.

    2004-04-14

    Reflection of a seismic wave from a plane interface betweentwo elastic media does not depend on the frequency. If one of the mediais poroelastic and fluid-saturated, then the reflection becomesfrequency-dependent. This paper presents a low-frequency asymptoticformula for the reflection of seismic plane p-wave from a fluid-saturatedporous medium. The obtained asymptotic scaling of the frequency-dependentcomponent of the reflection coefficient shows that it is asymptoticallyproportional to the square root of the product of the reservoir fluidmobility and the frequency of the signal. The dependence of this scalingon the dynamic Darcy's law relaxation time is investigated as well.Derivation of the main equations of the theory of poroelasticity from thedynamic filtration theory reveals that this relaxation time isproportional to Biot's tortuosity parameter.

  13. Application of low frequency and medium frequency currents in the management of acute and chronic pain-a narrative review.

    Science.gov (United States)

    Samuel, Stephen Rajan; Maiya, G Arun

    2015-01-01

    Trancutaneous electrical nerve stimulation (TENS) and interferential therapy (IFT) have been a regular line of treatment for various types of acute and chronic pain. This review aims to compile the latest literature in pain management using these modalities which use low-frequency and medium-frequency currents. The Cochrane Library, Scopus, PubMed, MEDLINE, and CINAHL were searched and studies were examined from their inception till October 2013. After title and abstract screening the relevant studies were included for this review. We found through this review that even though TENS and IFT are used in management of pain, there is limited amount of high quality research available in this area. Most of the studies lack methodological quality and have a low sample size.

  14. Application of low frequency and medium frequency currents in the management of acute and chronic pain-A narrative review

    Directory of Open Access Journals (Sweden)

    Stephen Rajan Samuel

    2015-01-01

    Full Text Available Trancutaneous electrical nerve stimulation (TENS and interferential therapy (IFT have been a regular line of treatment for various types of acute and chronic pain. This review aims to compile the latest literature in pain management using these modalities which use low-frequency and medium-frequency currents. The Cochrane Library, Scopus, PubMed, MEDLINE, and CINAHL were searched and studies were examined from their inception till October 2013. After title and abstract screening the relevant studies were included for this review. We found through this review that even though TENS and IFT are used in management of pain, there is limited amount of high quality research available in this area. Most of the studies lack methodological quality and have a low sample size.

  15. Application of Low Frequency and Medium Frequency Currents in the Management of Acute and Chronic Pain-A Narrative Review

    Science.gov (United States)

    Samuel, Stephen Rajan; Maiya, G Arun

    2015-01-01

    Trancutaneous electrical nerve stimulation (TENS) and interferential therapy (IFT) have been a regular line of treatment for various types of acute and chronic pain. This review aims to compile the latest literature in pain management using these modalities which use low-frequency and medium-frequency currents. The Cochrane Library, Scopus, PubMed, MEDLINE, and CINAHL were searched and studies were examined from their inception till October 2013. After title and abstract screening the relevant studies were included for this review. We found through this review that even though TENS and IFT are used in management of pain, there is limited amount of high quality research available in this area. Most of the studies lack methodological quality and have a low sample size. PMID:25709199

  16. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations.

    Science.gov (United States)

    Gao, Wang; Gao, Chengfa; Pan, Shuguo; Wang, Denghui; Deng, Jiadong

    2015-10-30

    The regional constellation of the BeiDou navigation satellite system (BDS) has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK) positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR). We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL) ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2) ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF) strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  17. Frequency pulling in a low-voltage medium-power gyrotron

    Science.gov (United States)

    Luo, Li; Du, Chao-Hai; Huang, Ming-Guang; Liu, Pu-Kun

    2018-04-01

    Many recent biomedical applications use medium-power frequency-tunable terahertz (THz) sources, such as sensitivity-enhanced nuclear magnetic resonance, THz imaging, and biomedical treatment. As a promising candidate, a low-voltage gyrotron can generate watt-level, continuous THz-wave radiation. In particular, the frequency-pulling effect in a gyrotron, namely, the effect of the electron beam parameters on the oscillation frequency, can be used to tune the operating frequency. Most previous investigations used complicated and time-consuming gyrotron nonlinear theory to study the influence of many beam parameters on the interaction performance. While gyrotron linear theory investigation demonstrates the advantages of rapidly and clearly revealing the physical influence of individual key beam parameters on the overall system performance, this paper demonstrates systematically the use of gyrotron linear theory to study the frequency-pulling effect in a low-voltage gyrotron with either a Gaussian or a sinusoidal axial-field profile. Furthermore, simulations of a gyrotron operating in the first axial mode are carried out in the framework of nonlinear theory as a contrast. Close agreement is achieved between the two theories. Besides, some interesting results are obtained. In a low-current sinusoidal-profile cavity, the ranges of frequency variation for different axial modes are isolated from each other, and the frequency tuning bandwidth for each axial mode increases by increasing either the beam voltage or pitch factor. Lowering the voltage, the total tuning ranges are squeezed and become concentrated. However, the isolated frequency regions of each axial mode cannot be linked up unless the beam current is increased, meaning that higher current operation is the key to achieving a wider and continuous tuning frequency range. The results presented in this paper can provide a reference for designing a broadband low-voltage gyrotron.

  18. Computational Vibroacoustics in Low- and Medium- Frequency Bands: Damping, ROM, and UQ Modeling

    Directory of Open Access Journals (Sweden)

    Roger Ohayon

    2017-06-01

    Full Text Available Within the framework of the state-of-the-art, this paper presents a summary of some common research works carried out by the authors concerning computational methods for the prediction of the responses in the frequency domain of general linear dissipative vibroacoustics (structural-acoustic systems for liquid and gas in the low-frequency (LF and medium-frequency (MF domains, including uncertainty quantification (UQ that plays an important role in the MF domain. The system under consideration consists of a deformable dissipative structure, coupled with an internal dissipative acoustic fluid including a wall acoustic impedance, and surrounded by an infinite acoustic fluid. The system is submitted to given internal and external acoustic sources and to prescribed mechanical forces. An efficient reduced-order computational model (ROM is constructed using a finite element discretization (FEM for the structure and the internal acoustic fluid. The external acoustic fluid is treated using a symmetric boundary element method (BEM in the frequency domain. All the required modeling aspects required for the analysis in the MF domain have been introduced, in particular the frequency-dependent damping phenomena and model uncertainties. An industrial application to a complex computational vibroacoustic model of an automobile is presented.

  19. Medium Band Least Squares Estimation of Fractional Cointegration in the Presence of Low-Frequency Contamination

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Varneskov, Rasmus T.

    This paper introduces a new estimator of the fractional cointegrating vector between stationary long memory processes that is robust to low-frequency contamination such as level shifts, i.e., structural changes in the means of the series, and deterministic trends. In particular, the proposed medium...... the cointegration strength and testing MBLS against the existing narrow band least squares estimator are developed. Finally, the asymptotic framework for the MBLS estimator is used to provide new perspectives on volatility factors in an empirical application to long-span realized variance series for S&P 500...

  20. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations

    Directory of Open Access Journals (Sweden)

    Wang Gao

    2015-10-01

    Full Text Available The regional constellation of the BeiDou navigation satellite system (BDS has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR. We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2 ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  1. Breathing as a low frequency wave propagation in nonlinear elastic permeable medium

    International Nuclear Information System (INIS)

    Kyriakou, Elizabeth; McKenzie, David R.; Suchowerska, Natalka; Fulton, Roger R.

    2007-01-01

    Breathing can be regarded as a type of low frequency wave propagation. Unlike sound propagation in open air, in breathing, the air compressibility is not as important as the flow of air, and to a first approximation the air can be regarded as incompressible. We have developed a one-dimensional analytical description of wave motion in a metamaterial consisting of a porous elastic medium contained within chambers, separated by plates with orifices representing the minor airways. The metamaterial is placed within a cylinder with impermeable sides representing the thorax, driven at one end by a piston representing the diaphragm. The incompressible air is able to escape from the top of the cylinder. The solutions to the wave equation have characteristics that depend on the values of permeability (defined by the size of the orifice in the plates), the Young's modulus of the elastic medium and the density of lung tissue. A 'normal' regime is identified in which the strain of the medium near the diaphragm is large and the strain at the top of the cylinder near the outlet is small. An 'abnormal' regime is also identified in which the opposite applies. A rapid transition between the two regimes can be caused by changing the parameters representing the lung tissue. This transition may represent the onset of a disease state such as asthma

  2. Electromagnetic Low-Frequency Dipolar Excitation of Two Metal Spheres in a Conductive Medium

    Directory of Open Access Journals (Sweden)

    Panayiotis Vafeas

    2012-01-01

    Full Text Available This work concerns the low-frequency interaction of a time-harmonic magnetic dipole, arbitrarily orientated in the three-dimensional space, with two perfectly conducting spheres embedded within a homogeneous conductive medium. In such physical applications, where two bodies are placed near one another, the 3D bispherical geometry fits perfectly. Considering two solid impenetrable (metallic obstacles, excited by a magnetic dipole, the scattering boundary value problem is attacked via rigorous low-frequency expansions in terms of integral powers (ikn, where n≥0, k being the complex wave number of the exterior medium, for the incident, scattered, and total non-axisymmetric electric and magnetic fields. We deal with the static (n=0 and the dynamic (n=1,2,3 terms of the fields, while for n≥4 the contribution has minor significance. The calculation of the exact solutions, satisfying Laplace’s and Poisson’s differential equations, leads to infinite linear systems, solved approximately within any order of accuracy through a cut-off procedure and via numerical implementation. Thus, we obtain the electromagnetic fields in an analytically compact fashion as infinite series expansions of bispherical eigenfunctions. A simulation is developed in order to investigate the effect of the radii ratio, the relative position of the spheres, and the position of the dipole on the real and imaginary parts of the calculated scattered magnetic field.

  3. Theoretical study of the infrared frequencies of crystalline methyl acetate under interstellar medium conditions.

    Science.gov (United States)

    Narayanan, Radhika; Inomata, Kensuke; Gopakumar, Geetha; Sivaraman, Bhalamurugan; Zempo, Yasunari; Hada, Masahiko

    2016-01-15

    Identification of methyl acetate in the interstellar medium (ISM) and its spectroscopic studies have prompted us to investigate the structure of crystalline methyl acetate using numerical calculations. Here, we present a theoretical study of the structure of crystalline methyl acetate and its isotopologues and compare the calculated infrared (IR) spectra with the available experimental data. The optimized structure and vibrational properties were calculated using SIESTA software at 0 K. In the optimization process, the Perdew-Burke-Ernzerhof functional and conjugate gradient methods were used with double zeta polarization basis functions. After optimization of the periodic structure, the vibrational frequencies and normal modes were calculated within the harmonic approximation. Using the calculated results, we refine the mode assignments of experimental work on crystalline methyl acetate and determine the low frequency modes (below 650 cm(-1)). To investigate the accuracy of the pseudopotential and confirm the IR frequencies, we performed molecular calculations using a periodic model of methyl acetate and its isotopologues using SIESTA and compared them with results obtained from Gaussian 09 (all electron method) calculations. Finally, we assigned the vibrational modes of crystalline CD3-COO-CH3 and CH3-COO-CD3, for which experimental data are not available in the crystalline phase under ISM conditions. For all of the calculation methods, the IR vibrational modes of molecular and crystalline methyl acetate and its isotopologues were in good agreement with the available experimental data and predict the unavailable values. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Multiple-Time-Scales Hierarchical Frequency Stability Control Strategy of Medium-Voltage Isolated Microgrid

    DEFF Research Database (Denmark)

    Zhao, Zhuoli; Yang, Ping; Guerrero, Josep M.

    2016-01-01

    In this paper, an islanded medium-voltage (MV) microgrid placed in Dongao Island is presented, which integrates renewable-energy-based distributed generations (DGs), energy storage system (ESS), and local loads. In an isolated microgrid without connection to the main grid to support the frequency....... In this way, dynamic stability control that cope with disturbances in short-time scale is implemented by microgrid central controller (MGCC) within Zone B and Zone C. Meanwhile, steady-state stability control to solve the peaks and valleys problem of loads and DGs in long-time scale is executed by microgrid...... energy management system (MEMS) within Zone A. Furthermore, based on the developed complete small-signal state-space model, sensitivity analysis of the eigenvalues is conducted in order to reveal the dynamic stability margin of the MV microgrid, and to identify the proper range of the control parameters...

  5. Evaluation of frequency-dependent ultrasound attenuation in transparent medium using focused shadowgraph technique

    Science.gov (United States)

    Iijima, Yukina; Kudo, Nobuki

    2017-07-01

    Acoustic fields of a short-pulsed ultrasound propagating through a transparent medium with ultrasound attenuation were visualized by the focused shadowgraph technique. A brightness waveform and its spatial integrations were derived from a visualized field image and compared with a pressure waveform measured by a membrane hydrophone. The experimental results showed that first-order integration of the brightness wave has good agreement with the pressure waveforms. Frequency-dependent attenuation of the pulse propagating through castor oil was derived from brightness and pressure waveforms, and attenuation coefficients determined from focused shadowgraphy and hydrophone techniques showed good agreement. The results suggest the usefulness of the shadowgraph technique not only for the visualization of ultrasound fields but also for noncontact estimation of rough pressure waveforms and correct ultrasound attenuation.

  6. Electric Field Simulations and Analysis for High Voltage High Power Medium Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Pei Huang

    2017-03-01

    Full Text Available The electronic power transformer (EPT raises concerns for its notable size and volume reduction compared with traditional line frequency transformers. Medium frequency transformers (MFTs are important components in high voltage and high power energy conversion systems such as EPTs. High voltage and high power make the reliable insulation design of MFT more difficult. In this paper, the influence of wire type and interleaved winding structure on the electric field distribution of MFT is discussed in detail. The electric field distributions for six kinds of typical non-interleaved windings with different wire types are researched using a 2-D finite element method (FEM. The electric field distributions for one non-interleaved winding and two interleaved windings are also studied using 2-D FEM. Furthermore, the maximum electric field intensities are obtained and compared. The results show that, in this case study, compared with foil conductor, smaller maximum electric field intensity can be achieved using litz wire in secondary winding. Besides, interleaving can increase the maximum electric field intensity when insulation distance is constant. The proposed method of studying the electric field distribution and analysis results are expected to make a contribution to the improvement of electric field distribution in transformers.

  7. A comparison of the analgesic efficacy of medium-frequency alternating current and TENS.

    Science.gov (United States)

    Ward, Alex R; Lucas-Toumbourou, Stacey; McCarthy, Brigid

    2009-12-01

    To compare the analgesic efficacy of burst-modulated medium-frequency alternating current (BMAC) and transcutaneous electrical nerve stimulation (TENS) using an experimental cold pain model. Within-group crossover study. A university research laboratory. Twenty healthy subjects. BMAC (4-kHz AC applied in 4-millisecond bursts at 50Hz) and TENS (125-microsecond phase duration applied at a frequency of 50Hz) administered to each participant on separate occasions. Time to cold pain threshold. The mean time to cold pain threshold with the BMAC intervention was no different than with TENS. Statistical analysis showed that both interventions elevated the cold pain threshold significantly [BMAC: increase=15.2seconds, 97.5% confidence interval (CI) 3.1 to 27.2, P=0.01; TENS: increase=15.4seconds, 97.5%CI 2.5 to 28.4, P=0.02], and the difference between interventions was not simply insignificant but the intervention effects were 'significantly the same' (mean difference=0.3seconds, 95%CI -15.3 to 15.9, P=0.97). BMAC is as effective as TENS in increasing cold pain thresholds in healthy subjects. Since BMAC has been shown to be more comfortable than TENS in previous studies and is likely to be better accepted and tolerated by patients, clinical investigation is warranted.

  8. Propagation of frequency-chirped laser pulses in a medium of atoms with a Λ-level scheme

    International Nuclear Information System (INIS)

    Demeter, G.; Dzsotjan, D.; Djotyan, G. P.

    2007-01-01

    We study the propagation of frequency-chirped laser pulses in optically thick media. We consider a medium of atoms with a Λ level-scheme (Lambda atoms) and also, for comparison, a medium of two-level atoms. Frequency-chirped laser pulses that induce adiabatic population transfer between the atomic levels are considered. They induce transitions between the two lower (metastable) levels of the Λ-atoms and between the ground and excited states of the two-level atoms. We show that associated with this adiabatic population transfer in Λ-atoms, there is a regime of enhanced transparency of the medium--the pulses are distorted much less than in the medium of two-level atoms and retain their ability to transfer the atomic population much longer during propagation

  9. Isolated lower mesospheric echoes seen by medium frequency radar at 70° N, 19° E

    Directory of Open Access Journals (Sweden)

    C. M. Hall

    2006-01-01

    Full Text Available We have noted sporadic instances of strong isolated reflections of medium frequency (MF radar waves from the mesosphere from as low as 50 km altitude and have devised a set of criteria for isolating these apparently anomalous echoes from those normally occurring from progressive partial reflections in the D-region. The object of this study is to map the occurrences of such echoes facilitating comparisons with other observations. For example, the similarity and simultaneity of the echo structure for the 20 January 2005 with VHF radar results presented by Lübken et al. (2006 are particularly striking. In presenting a number of such echo events since 2001 selected from the MF radar dataset (which spans 1997 to present, we find that virtually all echo occurrences coincide with enhanced solar proton fluxes suggesting that substantial ionisation of the mesosphere is a necessary condition. Strong partial reflections of the radio wave in the lower mesosphere combined with seasonally varying total absorption higher up, thus giving false impressions of lower mesospheric layers preferentially in winter, constitute a scenario consistent with our observations.

  10. Instantaneous Real-Time Kinematic Decimeter-Level Positioning with BeiDou Triple-Frequency Signals over Medium Baselines

    Directory of Open Access Journals (Sweden)

    Xiyang He

    2015-12-01

    Full Text Available Many applications, such as marine navigation, land vehicles location, etc., require real time precise positioning under medium or long baseline conditions. In this contribution, we develop a model of real-time kinematic decimeter-level positioning with BeiDou Navigation Satellite System (BDS triple-frequency signals over medium distances. The ambiguities of two extra-wide-lane (EWL combinations are fixed first, and then a wide lane (WL combination is reformed based on the two EWL combinations for positioning. Theoretical analysis and empirical analysis is given of the ambiguity fixing rate and the positioning accuracy of the presented method. The results indicate that the ambiguity fixing rate can be up to more than 98% when using BDS medium baseline observations, which is much higher than that of dual-frequency Hatch-Melbourne-Wübbena (HMW method. As for positioning accuracy, decimeter level accuracy can be achieved with this method, which is comparable to that of carrier-smoothed code differential positioning method. Signal interruption simulation experiment indicates that the proposed method can realize fast high-precision positioning whereas the carrier-smoothed code differential positioning method needs several hundreds of seconds for obtaining high precision results. We can conclude that a relatively high accuracy and high fixing rate can be achieved for triple-frequency WL method with single-epoch observations, displaying significant advantage comparing to traditional carrier-smoothed code differential positioning method.

  11. Electromagnetic Field and Lumped Circuit Analysis of Planar Transformer at Medium Frequency for Converter Application

    Directory of Open Access Journals (Sweden)

    Chengjian Lian

    2017-06-01

    Full Text Available High frequency planar transformer is a new type of transformer that operates at high frequency. Its significance is proved through its miniaturised features, high power density and other performances. The design of planar transformer needs to consider several fundamental factors, including core material, dimension of layers and winding pattern. As the volume decreases, extra attentions need to be paid in power losses and safety requirements. Different converter topologies, with planar transformer integrated, are also investigated and simulated for maximising the overall efficiency of conversion. Overall, the use of planar transformer in converters can bring several benefits, and, hence, there is a strong interest of comprehending its structure and high frequency behaviours.

  12. Electromyogram median power frequency in dynamic exercise at medium exercise intensities

    NARCIS (Netherlands)

    Ament, W; Bonga, GJJ; Hof, AL; Verkerke, GJ

    The electromyogram (EMG) median power Frequency of the calf muscles was investigated during an exhausting treadmill exercise and a 20-min recovery period. The exercise was an uphill run at a speed of 5 km . h(-1) and a gradient of 20%. During exercise there was no decrease of EMG median power

  13. Low-frequency pulse profile variation in PSR B2217+47: evidence for echoes from the interstellar medium

    Science.gov (United States)

    Michilli, D.; Hessels, J. W. T.; Donner, J. Y.; Grießmeier, J.-M.; Serylak, M.; Shaw, B.; Stappers, B. W.; Verbiest, J. P. W.; Deller, A. T.; Driessen, L. N.; Stinebring, D. R.; Bondonneau, L.; Geyer, M.; Hoeft, M.; Karastergiou, A.; Kramer, M.; Osłowski, S.; Pilia, M.; Sanidas, S.; Weltevrede, P.

    2018-02-01

    We have observed a complex and continuous change in the integrated pulse profile of PSR B2217+47, manifested as additional components trailing the main peak. These transient components are detected over 6 years at 150 MHz using the LOw Frequency ARray (LOFAR), but they are not seen in contemporaneous Lovell observations at 1.5 GHz. We argue that propagation effects in the ionized interstellar medium (IISM) are the most likely cause. The putative structures in the IISM causing the profile variation are roughly half-way between the pulsar and the Earth and have transverse radii R ˜ 30 AU. We consider different models for the structures. Under the assumption of spherical symmetry, their implied average electron density is \\overline{n}_e ˜ 100 cm-3. Since PSR B2217+47 is more than an order of magnitude brighter than the average pulsar population visible to LOFAR, similar profile variations would not have been identified in most pulsars, suggesting that subtle profile variations in low-frequency profiles might be more common than we have observed to date. Systematic studies of these variations at low frequencies can provide a new tool to investigate the proprieties of the IISM and the limits to the precision of pulsar timing.

  14. Performance Analysis of a Medium Frequency Offshore Grid for Identification Of Vessels Sailing on High Density Maritime European Routes

    Directory of Open Access Journals (Sweden)

    López Alfonso

    2017-12-01

    Full Text Available The paper analyses the performance of an Automatic Vessel Identification System on Medium Frequency (AVISOMEF, which works with the Grid Method (GM on high density maritime European routes using real data and uniformly distributed data. Compared to other systems, AVISOMEF is a novelty, as it is not a satellite system, nor is it limited by a given coverage distance, in contrast to the Automatic Identification System (AIS, though in exceptional circumstances it leans towards it. To perform the analysis, special simulation software was developed. Moreover, a number of maritime routes along with their traffic density data were selected for the study. For each route, two simulations were performed, the first of which based on the uniform traffic distribution along the route, while the second one made use of real AIS data positioning of vessels sailing on the selected routes. The obtained results for both simulations made the basis for formulating conclusions regarding the capacity of selected routes to support AVISOMEF.

  15. A Randomized Clinical Trial Comparing the Effectiveness of Electroacupuncture versus Medium-Frequency Electrotherapy for Discogenic Sciatica

    Directory of Open Access Journals (Sweden)

    Xue Zhang

    2017-01-01

    Full Text Available Objective. To investigate the short- and long-term effects of electroacupuncture (EA compared with medium-frequency electrotherapy (MFE on chronic discogenic sciatica. Methods. One hundred participants were randomized into two groups to receive EA (n=50 or MFE (n=50 for 4 weeks. A 28-week follow-up of the two groups was performed. The primary outcome measure was the average leg pain intensity. The secondary outcome measures were the low back pain intensity, Oswestry Disability Index (ODI, patient global impression (PGI, drug use frequency, and EA acceptance. Results. The mean changes in the average leg pain numerical rating scale (NRS scores were 2.30 (1.86–2.57 and 1.06 (0.62–1.51 in the EA and MFE groups at week 4, respectively. The difference was significant (P<0.001. The long-term follow-up resulted in significant differences. The average leg pain NRS scores decreased by 2.12 (1.70–2.53 and 0.36 (−0.05–0.78 from baseline in the EA and MFE groups, respectively, at week 28. However, low back pain intensity and PGI did not differ significantly at week 4. No serious adverse events occurred. Conclusions. EA showed greater short-term and long-term benefits for chronic discogenic sciatica than MFE, and the effect of EA was superior to that of MFE. The study findings warrant verification. This trial was registered under identifier ChiCTR-IPR-15006370.

  16. submitter Development of a 100 kW, 12.5 kV, 22 kHz and 30 kV insulated medium frequency transformer for compact and reliable medium voltage power conversion

    CERN Document Server

    Isler, Stephane; Aguglia, Davide; Bonnin, Xavier Abel

    2017-01-01

    This paper presents the critical design aspects addressed during the development of a 100 kW, 12.5 kV, 22 kHz, and 30 kV insulated medium frequency transformer used in a power converter. The transformers are used in a resonant multilevel converter topology producing HV DC voltage from a three phase 400 V AC industrial grid. The power converter is used to supply radio frequency systems in particle accelerators. Considerations about material selection, dielectric, magnetic and thermal design are discussed and experimental results on the full scale transformer and power converter are presented.

  17. Modulational instability of ultra-low-frequency shear dust Alfvén waves in a plasma medium of positive and negatively charged dust fluids

    International Nuclear Information System (INIS)

    Mamun, A. A.

    2014-01-01

    The propagation of finite amplitude ultra-low-frequency shear dust Alfvén (SDA) waves, and their modulational instability in a magnetized plasma medium of positive and negatively charged dust fluids have been theoretically investigated by using the reductive perturbation method. The derivative nonlinear Schrödinger equation is derived to examine the stability analysis of such SDA waves. It is found that the SDA waves propagating in such an opposite polarity dust plasma medium are modulationally unstable, and that the instability criterion and the growth rate of these unstable SDA waves in such a novel opposite polarity dust plasma medium are found to be significantly different from those in electron–ion or electron–positron plasma media. The implications of the present investigation in different space environments and laboratory devices are briefly discussed.

  18. An Approximate Treatment of Reflection Coefficient in the Phased Beam Tracing Method for the Simulation of Enclosed Sound Fields at Medium Frequencies

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Ih, Jeong-Guon; Rindel, Jens Holger

    2008-01-01

    The phased beam tracing method (PBTM) was suggested as a medium-frequency simulation technique for the calculation of impulse response, although main assumptions of geometric acoustics still hold. The phased method needs the reflection coefficient for characterizing the acoustic property of a sur......The phased beam tracing method (PBTM) was suggested as a medium-frequency simulation technique for the calculation of impulse response, although main assumptions of geometric acoustics still hold. The phased method needs the reflection coefficient for characterizing the acoustic property...... of a surface and the complex wave number for describing the propagation characteristics. In this study, two types of approximate real reflection coefficients derived from the measured absorption coefficient were tested for a practical applicability. As a test example, pressure impulse responses and energy...

  19. MULTI-FLUID APPROACH TO HIGH-FREQUENCY WAVES IN PLASMAS. I. SMALL-AMPLITUDE REGIME IN FULLY IONIZED MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Gómez, David; Soler, Roberto; Terradas, Jaume, E-mail: david.martinez@uib.es [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain)

    2016-12-01

    Ideal magnetohydrodynamics (MHD) provides an accurate description of low-frequency Alfvén waves in fully ionized plasmas. However, higher-frequency waves in many plasmas of the solar atmosphere cannot be correctly described by ideal MHD and a more accurate model is required. Here, we study the properties of small-amplitude incompressible perturbations in both the low- and the high-frequency ranges in plasmas composed of several ionized species. We use a multi-fluid approach and take into account the effects of collisions between ions and the inclusion of Hall’s term in the induction equation. Through the analysis of the corresponding dispersion relations and numerical simulations, we check that at high frequencies ions of different species are not as strongly coupled as in the low-frequency limit. Hence, they cannot be treated as a single fluid. In addition, elastic collisions between the distinct ionized species are not negligible for high-frequency waves, since an appreciable damping is obtained. Furthermore, Coulomb collisions between ions remove the cyclotron resonances and the strict cutoff regions, which are present when collisions are not taken into account. The implications of these results for the modeling of high-frequency waves in solar plasmas are discussed.

  20. Wave activity (planetary, tidal) throughout the middle atmosphere (20-100km) over the CUJO network: Satellite (TOMS) and Medium Frequency (MF) radar observations

    OpenAIRE

    A. H. Manson; C. E. Meek; T. Chshyolkova; S. K. Avery; D. Thorsen; J. W. MacDougall; W. Hocking; Y. Murayama; K. Igarashi

    2005-01-01

    Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT) is studied using combinations of ground-based (GB) and satellite instruments (2000-2002). The relatively new MFR (medium frequency radar) at Platteville (40° N, 105° W) has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opp...

  1. The frequency of a disease-causing point mutation in the gene coding for medium-chain acyl-CoA dehydrogenase in sudden infant death syndrome

    DEFF Research Database (Denmark)

    Banner, Jytte; Gregersen, N; Kølvraa, S

    1993-01-01

    syndrome is still a matter of controversy. The present study investigated 120 well-defined cases of sudden infant death syndrome in order to detect the frequency of the most common disease-causing point mutation in the gene coding for medium-chain acyl-CoA dehydrogenase (G985) compared with the frequency...... in the general population. A highly specific polymerase chain reaction assay was applied on dried blood spots. No over-representation of homo- or heterozygosity for G985 appears to exist in such a strictly defined population, for which reason it may be more relevant to look at a broader spectrum of clinical...... presentations of inherited metabolic disorders and examine a wider range of sudden death in infancy....

  2. Using radio frequency and ultrasonic antennas for inspecting pin-type insulators on medium-voltage overhead distribution lines

    Directory of Open Access Journals (Sweden)

    Cícero Lefort Borges

    2013-05-01

    Full Text Available This paper summarises the activities undertaken when using antennas (ultrasound and radiofrequency for identifying insulators in pre-failure state by detecting the noise emitted by the distribution line and correlating this with these insulators (porcelain pin type dielectric breakdown. This has led to developing low-cost maintenance procedures and providing support and criteria for engineer-ing decisions regarding replacing these insulators. The technique used two detectors; a radio frequency detector was used in a first investigation of a particular distribution line, set to 40 MHz and installed on the roof of a moving vehicle. The ultrasound detector was used for inspecting (phases A, B, C each structure (pole selected. Atmospheric conditions had no influence on defining pre-failure insulators (pin type based on the noise detection technique. Pin type insulators emitting noise should be replaced since measurement was made from the ground and near the base of the post.

  3. Planck intermediate results: XVII. Emission of dust in the diffuse interstellar medium from the far-infrared to microwave frequencies

    DEFF Research Database (Denmark)

    Bartlett, J.G.; Cardoso, J.-F.; Delabrouille, J.

    2014-01-01

    of 7500 deg2 centred on the southern Galactic pole. We present a general methodology to study the dust-H i correlation over the sky, including simulations to quantify uncertainties. Our analysis yields four specific results. (1) We map the temperature, submillimetre emissivity, and opacity of the dust per...... it with the far infrared spectral index βFIR derived from greybody fits at higher frequencies, and find a systematic difference, βmm -βFIR = -0.15, which suggests that the dust spectral energy distribution (SED) flattens at v ≤ 353 GHz. (3) We present spectral fits of the microwave emission correlated with Hi...... represent magnetic dipole emission. Alternatively, it could account for an increasing contribution of carbon dust, or a flattening of the emissivity of amorphous silicates, at millimetre wavelengths. These interpretations make different predictions for the dust polarization SED. (4) We analyse the residuals...

  4. Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

    Directory of Open Access Journals (Sweden)

    Jana Vlachová

    2015-03-01

    Full Text Available The stiffness of micron-sized sphere–plate contacts was studied by employing high frequency, tangential excitation of variable amplitude (0–20 nm. The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM, where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate (PMMA. The results from experiments undertaken in the dry state and in water are compared. Building on the shifts in the resonance frequency and resonance bandwidth, the instrument determines the real and the imaginary part of the contact stiffness, where the imaginary part quantifies dissipative processes. The method is closely analogous to related procedures in AFM-based metrology. The real part of the contact stiffness as a function of normal load can be fitted with the Johnson–Kendall–Roberts (JKR model. The contact stiffness was found to increase in the presence of liquid water. This finding is tentatively explained by the rocking motion of the spheres, which couples to a squeeze flow of the water close to the contact. The loss tangent of the contact stiffness is on the order of 0.1, where the energy losses are associated with interfacial processes. At high amplitudes partial slip was found to occur. The apparent contact stiffness at large amplitude depends linearly on the amplitude, as predicted by the Cattaneo–Mindlin model. This finding is remarkable insofar, as the Cattaneo–Mindlin model assumes Coulomb friction inside the sliding region. Coulomb friction is typically viewed as a macroscopic concept, related to surface roughness. An alternative model (formulated by Savkoor, which assumes a constant frictional stress in the sliding zone independent of the normal pressure, is inconsistent with the experimental data. The apparent friction coefficients slightly increase with normal force, which can be explained by nanoroughness. In other words, contact splitting

  5. Structural and Mechanical Properties of CrNx Coatings Deposited by Medium-Frequency Magnetron Sputtering with and without Ion Source Assistance

    International Nuclear Information System (INIS)

    Tian, C.X.; He, J.; Wang, H.J.; Fu, D.J.; Yang, B.

    2011-01-01

    CrNx coatings were deposited on Si (100) and WC-Co substrates by a home-made medium-frequency magnetron sputtering system with and without thermal filament ion source assistance. The structure and composition of the coatings were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and tribological properties were assessed by microhardness and pin-on-disc testing. The ion source-assisted system showed a deposition rate of 3.88 μm/h, much higher than the value 2.2 μm/h without ion source assistance. The CrNx coatings prepared with ion source assistance exhibited an increase in microhardness (up to 16.3 GPa) and a decrease in friction coefficient (down to 0.48) at the optimized cathode source-to-substrate distance.

  6. Frequency filter of seed x-ray by use of x-ray laser medium. Toward the generation of the temporally coherent x-ray laser

    International Nuclear Information System (INIS)

    Hasegawa, Noboru; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kouta; Tanaka, Momoko; Ochi, Yoshihiro; Nishikino, Masaharu; Nagashima, Keisuke; Kato, Yoshiaki; Renzhong, Tai

    2009-01-01

    We evaluate the characteristics of a higher-order harmonics light as a seed X-ray amplified through a laser-produced X-ray amplifier. The narrow spectral bandwidth of the X-ray amplifier works as the frequency filter of the seed X-ray, resulting in that only the temporally coherent X-ray is amplified. Experimental investigation using the 29th-order harmonic light of the Ti:sapphire laser at a wavelength of 26.9 nm together with a neon-like manganese X-ray laser medium shows evident spectral narrowing of the seed X-ray and amplification without serious diffraction effects on the propagation of the amplified X-ray beam. This implies that the present combination is potential to realize temporally coherent X-ray lasers, with an expected duration of approximately 400 fs. (author)

  7. Influence of vegetation physiognomy, elevation and fire frequency on medium and large mammals in two protected areas of the Espinhaço Range

    Directory of Open Access Journals (Sweden)

    Fernando Ferreira de Pinho

    2017-05-01

    Full Text Available ABSTRACT The objectives of this study were to determine the richness of medium and large mammal species in two protected areas of the Espinhaço Mountain Range, state of Minas Gerais, Brazil; and to investigate the factors affecting the occurrence of those species. To accomplish that we placed 49 camera traps activated by heat and motion at Rio Preto State Park (RPSP and 48 at Sempre Vivas National Park (SVNP. We also collected data on three environmental variables: vegetation physiognomy, elevation and wildfire frequency, to evaluate the influence of these factors on species richness and use intensity (inferred from camera trap detection rate by large mammals. We recorded 23 large mammal species in the two parks combined. The lowest species richness was found at the rupestrian habitat of RPSP, and in the open grasslands of SVNP. The forest and savannah physiognomies were used more intensively by large mammals. Species richness was higher and use was greater at lower elevations of RPSP. In SVNP, fire frequency did not affect species richness or use intensity. The savannah habitat had very similar richness compared to the forests of the two protected areas. The high species richness and use intensity observed in these forest habitats highlights the importance of riparian environments in the Cerrado biome. The highest species richness and use intensity observed at low elevation follows patterns found in the literature, probably due to variation in the vegetation, which results in greater resource availability. Although rupestrian habitats at high elevations of the Espinhaço Range are known to have a high degree of endemism for some taxa, large mammal richness and use were not high in this habitat. These results indicate that the protection of native vegetation at lower elevations is crucial for the long-term conservation of large mammals in the Espinhaço Range.

  8. Effect of thickness on structural, corrosion and mechanical properties of a thin ZrN film deposited by medium frequency (MF) reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Kavitha, Ayyalu; Kannan, Raman [Anna Univ., Dindigul (India). Dept. of Physics; Loganathan, Subramani [Titan Industries, Hosur, Tamilnadu (India). Ion Plating Dept.

    2016-07-01

    Zirconium nitride (ZrN) thin films were prepared on stainless steel (SS) substrates by medium frequency (MF) reactive sputtering with gas ion source (GIS) by varying the deposition time and obtained thickness (t{sub ZrN}) in the range of 1.25 to 3.24 μm. The effect of thickness on the structural and microstructural properties was studied using XRD and AFM. XRD characterization revealed that the texture of the ZrN thin films changes as a function of thickness. Both, the (111) and (200) peak, appear initially and (111) becomes more intense with increasing t{sub ZrN}. AFM imaging revealed that the ZrN thin film coated with t{sub ZrN} ∼ 3.24 μm shows larger grains that are uniformly distributed over the surface. An average hardness value of 19.79 GPa was observed for ZrN thin films having t{sub ZrN} ∼ 3.24 μm. The ZrN thin films having t{sub ZrN} ∼ 3.24 μm exhibits better adhesion strength up to 20 N. The electrochemical polarization studies indicated that the ZrN thin film having larger thickness shows improved corrosion resistance compared to SS in 3.5 % NaCl solution.

  9. Wave activity (planetary, tidal) throughout the middle atmosphere (20-100km) over the CUJO network: Satellite (TOMS) and Medium Frequency (MF) radar observations

    Science.gov (United States)

    Manson, A. H.; Meek, C. E.; Chshyolkova, T.; Avery, S. K.; Thorsen, D.; MacDougall, J. W.; Hocking, W.; Murayama, Y.; Igarashi, K.

    2005-02-01

    Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT) is studied using combinations of ground-based (GB) and satellite instruments (2000-2002). The relatively new MFR (medium frequency radar) at Platteville (40° N, 105° W) has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opportunity) comprises systems at London (43° N, 81° W), Platteville (40° N, 105° W), Saskatoon (52° N, 107° W), Wakkanai (45° N, 142° E) and Yamagawa (31° N, 131° E). It offers a significant 7000-km longitudinal sector in the North American-Pacific region, and a useful range of latitudes (12-14°) at two longitudes. Satellite data mainly involve the daily values of the total ozone column measured by the Earth Probe (EP) TOMS (Total Ozone Mapping Spectrometer) and provide a measure of tropopause-lower stratospheric planetary wave activity, as well as ozone variability. Climatologies of ozone and winds/tides involving frequency versus time (wavelet) contour plots for periods from 2-d to 30-d and the interval from mid 2000 to 2002, show that the changes with altitude, longitude and latitude are very significant and distinctive. Geometric-mean wavelets for the region of the 40° N MFRs demonstrate occasions during the autumn, winter and spring months when there are similarities in the spectral features of the lower atmosphere and at mesopause (85km) heights. Both direct planetary wave (PW) propagation into the MLT, nonlinear PW-tide interactions, and disturbances in MLT tides associated with fluctuations in the ozone forcing are considered to be possible coupling processes. The complex horizontal wave numbers of the longer period oscillations are provided in frequency contour plots for the TOMS satellite data to demonstrate the differences between lower atmospheric and MLT wave motions and their

  10. Wave activity (planetary, tidal throughout the middle atmosphere (20-100km over the CUJO network: Satellite (TOMS and Medium Frequency (MF radar observations

    Directory of Open Access Journals (Sweden)

    A. H. Manson

    2005-02-01

    Full Text Available Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT is studied using combinations of ground-based (GB and satellite instruments (2000-2002. The relatively new MFR (medium frequency radar at Platteville (40° N, 105° W has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opportunity comprises systems at London (43° N, 81° W, Platteville (40° N, 105° W, Saskatoon (52° N, 107° W, Wakkanai (45° N, 142° E and Yamagawa (31° N, 131° E. It offers a significant 7000-km longitudinal sector in the North American-Pacific region, and a useful range of latitudes (12-14° at two longitudes. Satellite data mainly involve the daily values of the total ozone column measured by the Earth Probe (EP TOMS (Total Ozone Mapping Spectrometer and provide a measure of tropopause-lower stratospheric planetary wave activity, as well as ozone variability. Climatologies of ozone and winds/tides involving frequency versus time (wavelet contour plots for periods from 2-d to 30-d and the interval from mid 2000 to 2002, show that the changes with altitude, longitude and latitude are very significant and distinctive. Geometric-mean wavelets for the region of the 40° N MFRs demonstrate occasions during the autumn, winter and spring months when there are similarities in the spectral features of the lower atmosphere and at mesopause (85km heights. Both direct planetary wave (PW propagation into the MLT, nonlinear PW-tide interactions, and disturbances in MLT tides associated with fluctuations in the ozone forcing are considered to be possible coupling processes. The complex horizontal wave numbers of the longer period oscillations are provided in frequency contour plots for the TOMS satellite data to demonstrate the differences between lower atmospheric and MLT wave motions and their

  11. Wave activity (planetary, tidal throughout the middle atmosphere (20-100km over the CUJO network: Satellite (TOMS and Medium Frequency (MF radar observations

    Directory of Open Access Journals (Sweden)

    A. H. Manson

    2005-02-01

    Full Text Available Planetary and tidal wave activity in the tropopause-lower stratosphere and mesosphere-lower thermosphere (MLT is studied using combinations of ground-based (GB and satellite instruments (2000-2002. The relatively new MFR (medium frequency radar at Platteville (40° N, 105° W has provided the opportunity to create an operational network of middle-latitude MFRs, stretching from 81° W-142° E, which provides winds and tides 70-100km. CUJO (Canada U.S. Japan Opportunity comprises systems at London (43° N, 81° W, Platteville (40° N, 105° W, Saskatoon (52° N, 107° W, Wakkanai (45° N, 142° E and Yamagawa (31° N, 131° E. It offers a significant 7000-km longitudinal sector in the North American-Pacific region, and a useful range of latitudes (12-14° at two longitudes. Satellite data mainly involve the daily values of the total ozone column measured by the Earth Probe (EP TOMS (Total Ozone Mapping Spectrometer and provide a measure of tropopause-lower stratospheric planetary wave activity, as well as ozone variability.

    Climatologies of ozone and winds/tides involving frequency versus time (wavelet contour plots for periods from 2-d to 30-d and the interval from mid 2000 to 2002, show that the changes with altitude, longitude and latitude are very significant and distinctive. Geometric-mean wavelets for the region of the 40° N MFRs demonstrate occasions during the autumn, winter and spring months when there are similarities in the spectral features of the lower atmosphere and at mesopause (85km heights. Both direct planetary wave (PW propagation into the MLT, nonlinear PW-tide interactions, and disturbances in MLT tides associated with fluctuations in the ozone forcing are considered to be possible coupling processes. The complex horizontal wave numbers of the longer period oscillations are provided in frequency contour plots for the TOMS satellite data to demonstrate the differences between lower atmospheric

  12. The effect of burst-duty-cycle parameters of medium-frequency alternating current on maximum electrically induced torque of the quadriceps femoris, discomfort, and tolerated current amplitude in professional soccer players.

    Science.gov (United States)

    Liebano, Richard Eloin; Waszczuk, Silas; Corrêa, Juliana Barbosa

    2013-12-01

    Repeated-measures, within-subject crossover trial. The primary objective was to assess the effect of the burst-duty-cycle parameters of medium-frequency alternating current on the maximum electrically induced torque of the quadriceps femoris. The secondary objectives were to evaluate the amount of discomfort tolerated and the maximum current amplitude delivered for each electrical-stimulation condition. Neuromuscular electrical stimulation used for muscle strengthening can improve functional performance. However, the electrical-stimulation parameters to achieve optimal outcomes are still unknown. Previous studies have demonstrated that the characteristics of the burst duty cycle of medium-frequency alternating current influence torque-generation levels and perception of sensory discomfort. The maximum electrically induced torque was assessed with a medium-frequency alternating current, with a carrier frequency of 2500 Hz and a modulated frequency of 50 Hz. The current amplitude was gradually increased to the point of the participant's maximum tolerance level. The testing sequence for the 3 burst duty cycles (20%, 35%, and 50%) was performed in a randomized order. Electrical stimulation using a 20% burst duty cycle produced an electrically induced torque greater than the 35% (P = .01) and 50% (P<.01) burst duty cycles, with no difference between the 35% and 50% burst duty cycles (P = .46). There was no difference in the amount of sensory discomfort produced by the 3 durations of burst duty cycles (P = .34). There was also no difference between the 3 conditions for the maximum current amplitude tolerated (P = .62). The burst duty cycle of 20% of medium-frequency alternating current, compared to burst duty cycles of 35% and 50%, produced higher peak torque of the quadriceps femoris in professional soccer players. There was no difference in discomfort produced and current amplitude tolerated between the different burst-duty-cycle conditions.

  13. Medium-Sized Mammals around a Radioactive Liquid Waste Lagoon at Los Alamos National Laboratory: Uptake of Contaminants and Evaluation of Radio-Frequency Identification Technology

    Energy Technology Data Exchange (ETDEWEB)

    Leslie A. Hansen; Phil R. Fresquez; Rhonda J. Robinson; John D. Huchton; Teralene S. Foxx

    1999-11-01

    Use of a radioactive liquid waste lagoon by medium-sized mammals and levels of tritium, other selected radionuclides, and metals in biological tissues of the animals were documented at Technical Area 53 (TA-53) of Los Alamos National Laboratory during 1997 and 1998. Rock squirrel (Spermophilus variegates), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), and bobcat (Lynx rufus) were captured at TA-53 and at a control site on the Santa Fe National Forest. Captured animals were anesthetized and marked with radio-frequency identification (RFD) tags and/or ear tags. We collected urine and hair samples for tritium and metals (aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and thallium) analyses, respectively. In addition, muscle and bone samples from two rock squirrels collected from each of TA-53, perimeter, and regional background sites were tested for tritium, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, and total uranium. Animals at TA-53 were monitored entering and leaving the lagoon area using a RFID monitor to read identification numbers from the RFID tags of marked animals and a separate camera system to photograph all animals passing through the monitor. Cottontail rabbit (Sylvilagus spp.), rock squirrel, and raccoon were the species most frequently photographed going through the RFID monitor. Less than half of all marked animals in the lagoon area were detected using the lagoon. Male and female rock squirrels from the lagoon area had significantly higher tritium concentrations compared to rock squirrels from the control area. Metals tested were not significantly higher in rock squirrels from TA-53, although there was a trend toward increased levels of lead in some individuals at TA-53. Muscle and bone samples from squirrels in the lagoon area appeared to have higher levels of tritium, total uranium, and {sup 137}Cs than samples collected from perimeter and

  14. Statistical characterization of high-to-medium frequency mesoscale gravity waves by lidar-measured vertical winds and temperatures in the MLT

    Science.gov (United States)

    Lu, Xian; Chu, Xinzhao; Li, Haoyu; Chen, Cao; Smith, John A.; Vadas, Sharon L.

    2017-09-01

    We present the first statistical study of gravity waves with periods of 0.3-2.5 h that are persistent and dominant in the vertical winds measured with the University of Colorado STAR Na Doppler lidar in Boulder, CO (40.1°N, 105.2°W). The probability density functions of the wave amplitudes in temperature and vertical wind, ratios of these two amplitudes, phase differences between them, and vertical wavelengths are derived directly from the observations. The intrinsic period and horizontal wavelength of each wave are inferred from its vertical wavelength, amplitude ratio, and a designated eddy viscosity by applying the gravity wave polarization and dispersion relations. The amplitude ratios are positively correlated with the ground-based periods with a coefficient of 0.76. The phase differences between the vertical winds and temperatures (φW -φT) follow a Gaussian distribution with 84.2±26.7°, which has a much larger standard deviation than that predicted for non-dissipative waves ( 3.3°). The deviations of the observed phase differences from their predicted values for non-dissipative waves may indicate wave dissipation. The shorter-vertical-wavelength waves tend to have larger phase difference deviations, implying that the dissipative effects are more significant for shorter waves. The majority of these waves have the vertical wavelengths ranging from 5 to 40 km with a mean and standard deviation of 18.6 and 7.2 km, respectively. For waves with similar periods, multiple peaks in the vertical wavelengths are identified frequently and the ones peaking in the vertical wind are statistically longer than those peaking in the temperature. The horizontal wavelengths range mostly from 50 to 500 km with a mean and median of 180 and 125 km, respectively. Therefore, these waves are mesoscale waves with high-to-medium frequencies. Since they have recently become resolvable in high-resolution general circulation models (GCMs), this statistical study provides an important

  15. Plasma chemistry of the sealed-off slab CO laser active medium pumped by radio-frequency discharge with liquid-nitrogen-cooled electrodes

    Science.gov (United States)

    Ionin, A. A.; Kozlov, A. Yu.; Seleznev, L. V.; Sinitsyn, D. V.

    2017-09-01

    The long-term time behavior of the output power of a sealed-off cryogenic slab CO laser pumped by a repetitively pulsed RF discharge and operating on the overtone (λ = 2.6-3.5 μm) vibrational-rotational transitions of the CO molecule was studied experimentally. It is shown that adding of an anomalously large amount of oxygen (up to 50% with respect to the CO concentration) to the initial gas mixture CO : He = 1 : 10 leads to a manyfold (by several tens of times) increase in the duration of the laser operating cycle (until lasing failure due to the degradation of the active medium). In this case, the laser life-time without replacement of the active medium reaches 105-106 pulses. Using various diagnostics (including luminescence spectroscopy and IR and UV absorption spectroscopy), regularities in the time-behavior of the concentrations of the main component of the active medium (CO molecules) and the products of plasmachemical reactions (O3, CO2) generated in the discharge gap during the laser operating cycle are revealed. Time correlation between the characteristics of the active medium and the laser output power are analyzed. A phenomenological approach to describing the entirety of plasmachemical, purely chemical, gas-dynamic, and diffusion processes determining the behavior of the laser output characteristics throughout the laser operating cycle is offered.

  16. Low-Frequency Observations of Galactic Supernova Remnants and the Distribution of Low-Density Ionized Gas in the Interstellar Medium

    National Research Council Canada - National Science Library

    Kassim, Namir E

    1989-01-01

    .... These observations are combined with other low-frequency data to derive free-free optical depths toward 47 SNRs and to constrain the physical properties of the ionized gas responsible for the absorption...

  17. Design considerations for a high power, medium frequency transformer for a DC-DC converter stage of a solid state transformer

    OpenAIRE

    Mumuluh, Roland Nshieteh

    2016-01-01

    ii. ABSTRACTIn recent years, the solid state transformer concept has challenged the conventional low frequency transformer. The conventional transformer cannot store energy and its output is easily distorted as a result of perturbations at its input. In same manner, disturbances from the output unit such as harmonics along with reactive power, as well as load transients are reflected back to the input of the conventional transformer. The size of the low frequency transformer is significantly ...

  18. Attenuation of low-frequency underwater sound using an array of air-filled balloons and comparison to effective medium theory.

    Science.gov (United States)

    Lee, Kevin M; Wilson, Preston S; Wochner, Mark S

    2017-12-01

    The ultimate goal of this work is to accurately predict the attenuation through a collection of large (on the order of 10-cm-radius) tethered encapsulated bubbles used in underwater noise abatement systems. Measurements of underwater sound attenuation were performed during a set of lake experiments, where a low-frequency compact electromechanical sound source was surrounded by different arrays of encapsulated bubbles with various individual bubbles sizes and void fractions. The measurements were compared with an existing predictive model [Church, J. Acoust. Soc. Am. 97, 1510-1521 (1995)] of the dispersion relation for linear propagation in liquid containing encapsulated bubbles. Although the model was originally intended to describe ultrasound contrast agents, it is evaluated here for large bubbles, and hence low frequencies, as a design tool for future underwater noise abatement systems, and there is good quantitative agreement between the observations and the model.

  19. Low and then high frequency oscillations of distinct right cortical networks are progressively enhanced by medium and long term Satyananda Yoga meditation practice

    Directory of Open Access Journals (Sweden)

    John eThomas

    2014-06-01

    Full Text Available Meditation proficiency is related to trait-like (learned effects on brain function, developed over time. Previous studies show increases in EEG power in lower frequency bands (theta, alpha in experienced meditators in both meditation states and baseline conditions. Higher gamma band power has been found in advanced Buddhist meditators, yet it is not known if this occurs in Yoga meditation practices. This study used eLORETA to compare differences in cortical source activity underlying scalp EEG from intermediate (mean experience 4 years and advanced (mean experience 30 years Australian meditators from the Satyananda Yoga tradition during a body-steadiness meditation, mantra meditation and non-meditation mental calculation condition. Intermediate Yoga meditators showed greater source activity in low frequencies (particularly theta and alpha1 during mental calculation, body-steadiness and mantra meditation. A similar spatial pattern of significant differences was found in all conditions but the number of significant voxels was double during body-steadiness and mantra meditation than in the non-meditation (calculation condition. These differences were greatest in right (R superior frontal and R precentral gyri and extended back to include the R parietal and occipital lobes. Advanced Yoga meditators showed greater activity in high frequencies (beta and especially gamma in all conditions but greatly expanded during meditation practice. Across all conditions (meditation and non-meditation differences were greatest in the same regions; R insula, R inferior frontal gyrus and R anterior temporal lobe. Distinct R core networks were identified in alpha1 (8-10 Hz and gamma (25-42 Hz bands respectively. The voxels recruited to these networks greatly expanded during meditation practice to include homologous regions of the left hemisphere. Functional interpretation parallels traditionally described stages of development in Yoga proficiency.

  20. Wave Activity (Planetary, Tidal) throughout the Middle Atmoshere (25-100 km) over the CUJO Network: Satellite and Medium Frequency (MF) Radar Observations

    Science.gov (United States)

    Manson, A.; Meek, C.; Chshyolkova, T.; Avery, S.; Thorsen, D.; MacDougall, J.; Hocking, W.; Murayama, Y.; Igarashi, K.

    Planetary and tidal wave activity in the mesosphere-lower thermosphere (MLT), and assessment of wave activity sources in the lower atmosphere, are studied using combinations of ground based (GB) and satellite instruments (2000-2002). CUJO (Canada U.S. Japan Opportunity) comprises MF radar (MFR) systems at London (43°N, 81°W), Platteville (40°N, 105°W), Saskatoon (52°N, 107°W), Wakkanai (45°N, 142°E) and Yamagawa (31°N, 131°E). It offers a significant mid-latitude 7,000 km longitudinal sector in the North American-Pacific region, and a useful range of latitudes (12-14°) at two longitudes. CUJO provides winds and tides 70-100km. Satellite data include the daily values of the total ozone column measured by the Earth Probe (EP) TOMS (Total Ozone Mapping Spectrometer) and provides a measure of tropopause-lower stratospheric planetary wave activity as well as ozone variability. The so-called UKMO data (an assimilation system) are used for correlative purposes with the TOMS data. Climatologies of ozone and winds/tides involving frequency versus time (wavelet) contour plots for periods from 2-d to 30-d and the interval from mid 2000 to 2002, show that the changes with altitude, longitude and latitude are very significant and distinctive. Geometric-mean wavelets for the region of the 40°N MFRs demonstrate occasions during the autumn, winter and spring months when there are similarities in the spectral features of the lower atmosphere and at mesopause (85km) heights. Both direct planetary wave (PW) propagation into the MLT, non-linear PW-tide interactions, and disturbances in MLT tides associated with fluctuations in the ozone forcing are considered to be possible coupling processes. The complex horizontal wave numbers of the longer period oscillations are provided in frequency contour plots for the TOMS and UKMO data to demonstrate the differences between lower atmospheric and MLT wave motions and their directions of propagation.

  1. Diferentes tempos de eletroestimulação neuromuscular (eenm de média frequência (kotz em cães Different times of neuromuscular electrical stimulation medium frequency (kotz in dogs

    Directory of Open Access Journals (Sweden)

    Charles Pelizzari

    2011-09-01

    Full Text Available O objetivo desta pesquisa foi empregar a estimulação elétrica neuromuscular (EENM de média frequência no músculo quadríceps femoral de cães com atrofia muscular induzida, avaliar o ganho de massa muscular e comparar a EENM sob diferentes tempos de tratamento. Foram utilizados oito cães, pesando entre 15 e 25kg e distribuídos aleatoriamente em dois grupos denominados de GI (30minutos e GII (60minutos. Para a indução da atrofia muscular, a articulação do joelho direito foi imobilizada por 30 dias por transfixação percutânea tipo II. Após a retirada do aparelho de imobilização, foi realizada a EENM nos cães dos grupos GI e GII três vezes por semana, com intervalo mínimo de 48 horas entre cada sessão, pelo período de 60 dias. Foram mensuradas a perimetria da coxa, goniometria dos joelhos, atividade da enzima creatina-quinase (CK e morfometria das fibras musculares do vasto lateral em cortes transversais colhido mediante a biópsia muscular. Não houve diferença quanto aos valores da perimetria da coxa e atividade da enzima CK. A goniometria revelou significância (PThe aim of this study was to use medium frequency Neuromuscular Electrical Stimulation (NMES in femoral quadriceps muscle of dogs with induced muscular atrophy to evaluate the occurrence of mass gain in these muscles and to compare NMES in different periods of treatment. Eight dogs, weighing between 15 and 25kg, were randomly placed in two groups: GI (NMES for 30min, GII, (NMES for 60min. For the muscular atrophy induction, the right knee was immobilized for 30 days by the percutaneous transfixation type II method. NMES was carried out in the dogs of which groups, three times a week, in between 48h each session, in a period of 60 days. The parameters measured were: thigh perimetry, knee goniometry, creatine kinase (CK enzyme activity and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle, collected through a muscular biopsy

  2. [Workplace Health Promotion in Small, Medium-Sized and Large Enterprises of the Health-Care Sector - Frequency, Reasons for the Company Management to Take Action and Barriers to Implementation].

    Science.gov (United States)

    Schaefer, E; Drexler, H; Kiesel, J

    2016-03-01

    The aim of this study was to gain insight into worksite health promotion in small and medium-sized companies compared to large concerns in Middle Franconia. Action in worksite health promotion, obstacles and demand for networks for workplace health promotion were determined. A standardised telephone interview served for collecting data for this cross-sectional study. The interviewee was always the manager or their proxy. 106 companies were contacted. The results of this study were analysed via qualitative and quantitative methods in SPSS(®) 20. It was possible to reach and interview 80 companies, a return rate of 75.5%. More than half the companies (68.8%) implemented at least one activity for worksite health promotion, especially ergonomic measures and measures to promote physical activity. Taking the size of the company into consideration when analysing the results, previous study results are confirmed. With an increasing size of the company, the relative frequency of measures for workplace health promotion rises. The motivation for worksite health promotion ranges from keeping the employees healthy (38.2%) to worksite health promotion as part of the business culture (9.1%). 81.1% of the companies consider their activity in worksite health promotion to be successful. Furthermore, 80.0% of the firms that implemented worksite health promotion were supported by a partner like a health insurance (43.2%). Those companies that did not implement any activities for worksite health promotion, state as a prime reason that they did not think about it as yet (44.0%). Besides, 44.0% of the companies without any worksite health promotion would like to implement measures. 65.5% of the companies that already took action in worksite health promotion and 56.0% of the companies that did not would like to cooperate with other firms in a network for workplace health promotion. Mutual exchange is the most important factor for them. The results of this study show that almost half of

  3. The frequency of clinical pregnancy and implantation rate after cultivation of embryos in a medium with granulocyte macrophage colony-stimulating factor (GM-CSF) in patients with preceding failed attempts of ART.

    Science.gov (United States)

    Tevkin, S; Lokshin, V; Shishimorova, M; Polumiskov, V

    2014-10-01

    The application in IVF practice of modern techniques can improve positive outcome of each cycle in the assisted reproductive technology (ART) programs and the effectiveness of treatment as a whole. There are embryos in the female reproductive tract in physiological medium which contain various cytokines and growth factors. It plays an important role in the regulation of normal embryonic development, improve implantation and subsequently optimizing the development of the fetus and the placenta. Granulocyte macrophage colony-stimulating factor (GM-CSF is one of the cytokines playing an important role in reproductive function. Addition of recombinant GM-CSF to the culture medium can makes closer human embryos culture to in vivo conditions and improve the efficacy ART cycles. The analysis of culture embryos in EmbryoGen medium has shown that fertilization rate embryo culture and transfer to patients with previous unsuccessful attempts increases clinical pregnancy rate compared to the control group 39.1 versus 27.8%, respectively. It is noted that the implantation rate (on 7 weeks' gestation) and progressive clinical pregnancy rate (on 12 weeks' gestation) were significantly higher in group embryos culture in EmbryoGen medium compared to standard combination of medium (ISM1+VA), and were 20.4 and 17.4% versus 11.6 and 9.1%, respectively.

  4. Comparison of the Effect of Dual-Axis Rotational Coronary Angiography Versus Conventional Coronary Angiography on Frequency of Acute Kidney Injury, X-Ray Exposure Time, and Quantity of Contrast Medium Injected.

    Science.gov (United States)

    Di Serafino, Luigi; Turturo, Maurizio; Lanzone, Saverio; Marano, Melissa; Scognamiglio, Gabriella; Trimarco, Bruno; Cirillo, Plinio; Esposito, Giovanni; D'Agostino, Carlo

    2018-02-07

    Dual-axis rotational coronary angiography (DARCA) has already been shown to reduce both the amount of contrast medium and radiation exposure compared with conventional coronary angiography (CCA). However, a clinical benefit of such imaging modality has never been demonstrated. The aim of this study was to evaluate the efficacy of DARCA to prevent acute kidney injury (AKI) compared with CCA. Consecutive patients who underwent coronary angiography were enrolled to DARCA (n = 80) or CCA (n = 80). Patients presenting with ST-segment elevation myocardial infarction or previously underwent coronary artery bypass graft were excluded. The 2 groups were homogeneous in terms of both clinical and procedural characteristics. Total x-ray time and total amount of contrast medium were significantly lower in the DARCA group compared with the CCA group (x-ray time 3.2 minutes [1.8 to 7.0] vs 5.1 minutes [2.6 to 9.9], p = 0.002; contrast medium amount 40 ml [31 to 116] vs 80 ml [50 to 150], p <0.001). AKI more often occurred in the CCA group compared with the DARCA group (16 [20%] vs 4 [5%], p = 0.007). Moreover, in patients presenting with acute coronary syndrome (ACS) or who underwent percutaneous coronary intervention (PCI), AKI more often occurred in the CCA group compared with the DARCA group (ACS patients, 6 [29%] vs 2 [6%], p = 0.04, and PCI patients, 11 [33%] vs 0 [0%], p <0.001). In addition, in patients with high pretest probability of coronary artery disease, AKI more often occurred in the CCA group compared with the DARCA group (11 [55%] vs 2 [6%], p <0.001). In conclusion, DARCA significantly reduces both x-ray exposure and amount of contrast medium usage, thereby reducing the occurrence of AKI compared with CCA. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. A High-Speed High-Frequency Broadband Acoustic Modem for Short-to-Medium Range Data Transmission in Ports, Very Shallow Waters and Deep Waters Using Spread-Spectrum Modulation and Decision Feedback Equalizing

    National Research Council Canada - National Science Library

    Beaujean, Pierre-Philippe; Spruance, John; Kriel, Dion

    2006-01-01

    ...: The long-term objective is the commercialization of a high-speed high-frequency acoustic modem transmitting data at true rates of up to 105,000 bps, at a maximum range of 500 m and operate between 240 kHz and 380 kHz...

  6. Comparação do índice de desconforto sensorial durante a estimulação elétrica neuromuscular com correntes excitomotoras de baixa e média frequência em mulheres saudáveis Comparison of the sensory discomfort index during neuromuscular electrical stimulation with low and medium excitomotor frequencies in healthy women

    Directory of Open Access Journals (Sweden)

    Richard Eloin Liebano

    2009-02-01

    Full Text Available INTRODUÇÃO: A estimulação elétrica neuromuscular é uma estratégia clínica para aumento da performance muscular. Sabe-se que um dos principais fatores limitantes da estimulação elétrica para aumento de força é o desconforto causado pelas correntes utilizadas. OBJETIVO: O objetivo deste estudo foi comparar o nível de desconforto sensorial causado por correntes de baixa e média freqüência na estimulação elétrica neuromuscular do músculo quadríceps femoral. MÉTODOS: Participaram do estudo 45 voluntárias saudáveis com idade entre 18 e 30 anos. Todas as voluntárias foram submetidas à estimulação elétrica com correntes de baixa e média freqüência. A análise do desconforto sensorial foi feita por meio de uma escala visual analógica (EVA. RESULTADOS: Os resultados revelaram um valor médio de 6,1 para o desconforto sensorial na estimulação de baixa freqüência (BF e de 6,4 para a estimulação de média freqüência (MF, não havendo diferença estatisticamente significante entre elas (p = 0,61. Em relação às intensidades utilizadas, a média foi de 45,64mA para a estimulação de BF e 121,67mA na estimulação com a MF, sendo essa diferença estatisticamente significante (p INTRODUCTION: Neuromuscular electrical stimulation is a clinical strategy for increasing of muscular performance. It is known that one of the main limiting factors of the electrical stimulation for strength increase is the discomfort caused by the currents used in the process. OBJECTIVE: The objective of this study was to compare the level of sensory discomfort caused by low and medium frequency currents in the neuromuscular electrical stimulation of the quadriceps femoris muscle. METHODS: Forty-five female healthy volunteers with age between 18 and 30 years participated in the study. All the volunteers were submitted to electrical stimulation with low and medium frequency. Sensory discomfort was measured using the Visual Analogue Scale (VAS

  7. Hadrons in medium

    Indian Academy of Sciences (India)

    medium properties of hadrons. I discuss the relevant symmetries of QCD and how they might affect the observed hadron properties. I then discuss at length the observable consequences of in-medium changes of hadronic properties in reactions with ...

  8. Medium is the message

    NARCIS (Netherlands)

    Kuipers, G.; Ritzer, G.

    2012-01-01

    "The medium is the message" is a phrase coined by Canadian media theorist Marshall McLuhan (1911-1980), in his book Understanding Media: The Extensions of Man (1964). In this book, McLuhan examines the impact of media on societies and human relations, arguing for the primacy of the medium -

  9. Local interstellar medium

    International Nuclear Information System (INIS)

    Crutcher, R.M.; and Radio Astronomy Laboratory, University of California, Berkeley)

    1982-01-01

    Analysis of the velocities of optical interstellar lines shows that the Sun is immersed in a coherently moving local interstellar medium whose velocity vector agrees with that of the interstellar wind observed through backscatter of solar H Lyα and He lambda584 photons. The local interstellar medium consists of both cool clouds and warm intercloud medium gas, has a mass of perhaps approx.30 M/sub sun/, does not have severe depletion of trace elements from the gas phase, and appears to be material which has been shocked and accelerated by stellar winds and supernovae associated with the Sco-Oph OB association

  10. HIRENASD medium unstructured

    Data.gov (United States)

    National Aeronautics and Space Administration — Unstructured HIRENASD mesh: - medium size (16 million nodes, 39 million elements) - for node centered solvers - 31.05.2011 - caution: dimensions in mm

  11. Concept medium programme

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2005-01-01

    The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program...

  12. Concept medium programme

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2005-01-01

    The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program......The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program...

  13. Defined medium for Moraxella bovis.

    OpenAIRE

    Juni, E; Heym, G A

    1986-01-01

    A defined medium (medium MB) for Moraxella bovis was formulated. Nineteen strains grew well on medium MB. One strain was auxotrophic for asparagine, and another was auxotrophic for methionine. Strains of M. equi and M. lacunata also grew on medium MB. All strains had an absolute requirement for thiamine and were stimulated by or actually required the other growth factors in the medium.

  14. Spiegel. Medium. Kunst

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    and cultural perspective. From 1800 on, the great incentive was to push forward the material-physical and optical-mechanical and especially the media ‘exploitation’ of the mirror. The significance of the mirror as a central meta-medium of the visual emerged in a particularly striking way in the late 1830s....... That ricochets through media theory, theories of art and culture and through cultural historiography. A repository is one thing, a transmitter another: the distinction will act crucially on the quest for appropriate perspectives and classifications of what in terms of disciplines would rather appear...... or as synaesthesia gone mute. It stands in contrast with the mirror, which assumes the status of a medium facility or meta-medium of visual transference, encountering its only medial and operative limitation within the analogue or digital repository media. The present proposal for an artistic and cultural history...

  15. DYNAMIC DEFORMATION THE VISCOELASTIC TWOCOMPONENT MEDIUM

    Directory of Open Access Journals (Sweden)

    V. S. Polenov

    2015-01-01

    Full Text Available Summary. In the article are scope harmonious warping of the two-component medium, one component which are represent viscoelastic medium, hereditary properties which are described by the kernel aftereffect Abel integral-differential ratio BoltzmannVolterr, while second – compressible liquid. Do a study one-dimensional case. Use motion equation of two-component medium at movement. Look determination system these equalization in the form of damped wave. Introduce dimensionless coefficient. Combined equations happen to homogeneous system with complex factor relatively waves amplitude in viscoelastic component and in fluid. As a result opening system determinant receive biquadratic equation. Elastic operator express through kernel aftereffect Abel for space Fourier. With the help transformation and symbol series biquadratic equation reduce to quadratic equation. Come to the conclusion that in two-component viscoelastic medium exist two mode sonic waves. As a result solution of quadratic equation be found description advance of waves sonic in viscoelastic two-component medium, which physical-mechanical properties represent complex parameter. Velocity determination advance of sonic waves, attenuation coefficient, mechanical loss tangent, depending on characteristic porous medium and circular frequency formulas receive. Graph dependences of description advance of waves sonic from the temperature logarithm and with the fractional parameter γ are constructed.

  16. Concept medium program

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2003-01-01

    The present essays is an attempt to dertermine the architecural project of the 21st century in realation to a modern conception of space as the medium of architecture, and of society as its program. This attempt adopts the internal point of view of an architect in describing a modern architectura...

  17. Radon in geological medium

    International Nuclear Information System (INIS)

    Hricko, J.

    1995-01-01

    The paper presented deals with behavior of the radon in geological medium and with some results of the radon survey in Bratislava and Kosice regions. 1) The a v has been detected in the holes 0.80 m deep. The density of observations - 3 reference areas (one represents 20 stations) per 1 km 2 . The radon risk maps in 1:25000 and 1:50000 scales have been compiled. The 56.8% of the project area lies in low radon risk, 37.6% in medium radon risk and 5.6% in high radon risk. Follow-up monitoring of the equivalent volume radon activity (EVRA) at the flats, located in the areas with high radon risk of the surface layer, has showed values several times higher than Slovak limits (Marianka, Raca, Vajnory). The evidence that neotectonic is excellent medium for rising up emanation to the subsurface layer, is shown on the map. The tectonic zone of Liscie udolie in Bratislava-Karlova Ves area has been clearly detected by profile radon survey (a v > 50 kBq/m 3 ). 2) At present, northern half of the area of Kosice in question was covered by radon survey. The low and medium radon risks have been observed here, while localities with high radon risk are small in extent. The part of radon risk and soil permeability map from northern Kosice area is shown. (J.K.) 3 figs., 2 refs

  18. Estimulação elétrica neuromuscular de média freqüência (russa em cães com atrofia muscular induzida Medium frequency neuromuscular electrical stimulation (russian in dogs with induced muscle atrophy

    Directory of Open Access Journals (Sweden)

    Charles Pelizzari

    2008-06-01

    Full Text Available A estimulação elétrica neuromuscular (EENM de média freqüência (Russa ou de Kotz pode ser empregada para a recuperação de massa muscular em animais apresentando atrofia muscular por desuso. Assim, o objetivo deste trabalho foi empregar a EENM de média freqüência no quadríceps femoral de cães com atrofia muscular induzida, avaliando-se a ocorrência de ganho de massa. Foram utilizados oito cães em dois grupos denominados de GI ou controle e de GII ou tratado. Para a indução da atrofia muscular, a articulação fêmoro-tíbio-patelar esquerda foi imobilizada por 30 dias. Após 48 horas da remoção, foi realizada a EENM nos cães do grupo II, três vezes por semana, com intervalo de 48 horas cada sessão, pelo período de 60 dias. Foram avaliadas a mensuração da perimetria da coxa, da goniometria do joelho, as enzimas creatina-quinase (CK e morfometria das fibras musculares em cortes transversais do músculo vasto lateral, colhido mediante a biópsia muscular. A EENM foi empregada no músculo quadríceps femoral numa freqüência de 2.500Hz, largura de pulso de 50% e relação de tempo on/off de 1:2. Não houve diferença significativa quanto aos valores de perimetria da coxa e a atividade da enzima CK entre os grupos I e II. Na goniometria, houve diminuição significativa (PThe medium frequency neuromuscular electrical stimulation (NMES (Russa or Kotz is designed for recuperation of muscle mass in dogs with muscular atrophy in disuse. This study aims to utilize medium frequency NMES on the femoral quadriceps of dogs with induced muscular atrophy and evaluate the occurrence of gain in mass. Eight dogs in two groups denominated GI, or control, and GII, or treated were used. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days. NMES treatment began 48 hours after the removal of the immobilization device on dogs from group II and was carried out three times per week, with an

  19. Effect of switching-off of a plasma medium on a traveling wave

    International Nuclear Information System (INIS)

    Kalluri, D.K.

    1989-01-01

    It is known that a sudden creation of a plasma medium of plasma frequency ω ρ splits a traveling wave of frequency ω o into two new waves of frequencies. The negative value for the frequency here indicates a reflected wave. The effect of a sudden collapse of the plasma medium, on a travelling wave of frequency ω o is shown to be the creation of two new waves of frequencies. A numerical solution is obtained for the case of a gradual collapse of the plasma medium. For the case of a slow decay of the particle density an approximate WKB type solution is obtained. Several results are presented

  20. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    of the rectangles and sums all contributions to arrive at the spatial impulse response for the aperture and field point. This approach makes it possible to model all transducer apertures, and the program can readily calculate the emitted, pulse-echo and continuous wave field. Attenuation is included by splitting...... it into a frequency dependent part and frequency independent part. The latter results in an attenuation factor that is multiplied onto the responses from the individual elements, and the frequency dependent part is handled by attenuating the basic one-dimensional pulse. The influence on ultrasound fields from......Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...

  1. Medium-energy physics

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    One of the basic challenges of medium-energy physics is the development of a clear picure of the manner in which pions propagate in nuclear matter. Since the pion is a basic quantum of the nuclear force, understanding its propagation in nuclei contributes to our understanding of the basic nature of nuclear forces. Key to such understanding is a comprehensive and precise experimental description of pion interactions both with complex nuclei and few nucleon systems. This is a major objective of the ANL effort in medium-energy physics. Experiments are carried out as a part of a comprehensive nuclear program, and, because of this perspective, the pion studies are expected to give new insights into the nature of nuclear forces. At the present time, almost all experimental activity is concentrated on measurements using various pion beams of the Los Alamos Meson Physics Facility

  2. Liquid chromatographic extraction medium

    Science.gov (United States)

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  3. Hadrons in the medium

    International Nuclear Information System (INIS)

    Leupold, Stefan

    2005-01-01

    QCD, the theory of the strong interaction, has a non-trivial vacuum structure. One way to characterize this structure is by means of non-vanishing matrix elements of quark or gluon operators, the condensates. In hot and/or dense enough strongly interacting media, QCD is subject to phase transitions or rapid crossovers. Consequently, the condensates typically change with density and temperature. An exciting aspect of hadron physics is the question how these changes affect the properties of hadrons which are put in a strongly interacting environment. Here vector mesons deserve special attention as they couple directly to (virtual) photons. The latter can decay into dileptons which leave the strongly interacting system untouched. Via that process information about possible in-medium modifications of the vector mesons can be carried to the detectors. With the ω-meson as an example I will review our current understanding of the connections between in-medium changes of condensates and the in-medium changes of the properties of hadrons. (author)

  4. Radiculography with reduced amounts of contrast medium

    International Nuclear Information System (INIS)

    Signorini, E.; Caputo, N.; Chiurulla, C.; Ciorba, E.; Pelliccioli, G.P.; Cianciulli, E.

    1984-01-01

    Because of the frequency and seriousness of side effects observed after radiculography, due to, among the other things, the amount of contrast medium, the authors describe a method that gives diagnostically satisfactory results using a low dose of contrast and a tangent-beam technique. Among 106 patients undergoing radiculography with a tangent-beam technique and Iopamidol, only 4 developed mild side effects, namely headache in three cases and headache with nausea in one. (Author)

  5. Spiegel. Medium. Kunst

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    to human talent, came the millennia of untiring labours and the play of art and science and thought. The human love-affair with reflection (to cite Mark Pendergast’s subtitle - Mirror/Mirror: A History of the Human Love Affair with Reflection [New York 2003]) has always been a platonic one and I hold...... and cultural perspective. From 1800 on, the great incentive was to push forward the material-physical and optical-mechanical and especially the media ‘exploitation’ of the mirror. The significance of the mirror as a central meta-medium of the visual emerged in a particularly striking way in the late 1830s...

  6. DENSE MEDIUM CYCLONE OPTIMIZATON

    Energy Technology Data Exchange (ETDEWEB)

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  7. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  8. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  9. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  10. Propagation of monochromatic light in a hot and dense medium

    Science.gov (United States)

    Masood, Samina S.

    2017-12-01

    Photons, as quanta of electromagnetic fields, determine the electromagnetic properties of an extremely hot and dense medium. Considering the properties of the photons in the interacting medium of charged particles, we explicitly calculate the electromagnetic properties such as the electric permittivity, magnetic permeability, refractive index and the propagation speed of electromagnetic signals in an extremely hot and dense background. Photons acquire a dynamically generated mass in such a medium. The screening mass of the photon, the Debye shielding length and the plasma frequency are calculated as functions of the statistical parameters of the medium. We study the properties of the propagating particles in astrophysical systems of distinct statistical conditions. The modifications in the properties of the medium lead to the equation of state of the system. We mainly calculate all these parameters for extremely high temperatures of the early universe.

  11. Propagation of monochromatic light in a hot and dense medium

    Energy Technology Data Exchange (ETDEWEB)

    Masood, Samina S. [University of Houston Clear Lake, Department of Physical and Applied Sciences, Houston, TX (United States)

    2017-12-15

    Photons, as quanta of electromagnetic fields, determine the electromagnetic properties of an extremely hot and dense medium. Considering the properties of the photons in the interacting medium of charged particles, we explicitly calculate the electromagnetic properties such as the electric permittivity, magnetic permeability, refractive index and the propagation speed of electromagnetic signals in an extremely hot and dense background. Photons acquire a dynamically generated mass in such a medium. The screening mass of the photon, the Debye shielding length and the plasma frequency are calculated as functions of the statistical parameters of the medium. We study the properties of the propagating particles in astrophysical systems of distinct statistical conditions. The modifications in the properties of the medium lead to the equation of state of the system. We mainly calculate all these parameters for extremely high temperatures of the early universe. (orig.)

  12. Birefringence in a chiral medium, via temporal cloaking

    Science.gov (United States)

    Khan, Humayun; Haneef, Muhammad

    2017-05-01

    This paper reports theoretical investigation of birefringence in a chiral medium for the creation of temporal cloaking. The chiral medium splits the input probe beam into left/right circular polarized beams. These left/right circular polarized beams are then controlled and modified within the chiral medium. The left circular polarized beam delays by 24 ns whereas the right circular polarized beam advances by  -23 ns at a control field of rabbi frequency 6γ . This opens a 47 ns time gap for temporal cloaking to hide information without noise corruption and energy loss. The results have potential applications in communication devices for secure propagation of light pulse.

  13. Open waveguide cavity using a negative index medium.

    Science.gov (United States)

    Yan, Wei; Shen, Linfang

    2008-12-01

    An open waveguide cavity formed by a pair of planar waveguides, in which one guiding layer is a negative index medium and the other is a positive index medium, is theoretically demonstrated. For such a waveguide cavity the resonant frequency is independent of the total length of the waveguide system. With the coupled mode theory it is shown that energy flow circulation can be established through the special coupling between the waveguides at the resonant frequency, and thus the wave fields are localized. This phenomenon is further verified numerically with the finite-difference time-domain method. The quality factor of the open waveguide cavity is also discussed.

  14. Pions in the nuclear medium

    International Nuclear Information System (INIS)

    Chanfray, G.

    1996-07-01

    We discuss various aspects of pion physics in the nuclear medium. We first study s-wave pion-nucleus interaction in connection with chiral symmetry restoration and quark condensate in the nuclear medium. We then address the question of p-wave pion-nucleus interaction and collective pionic modes in nuclei and draw the consequences for in medium ππ correlations especially in the scalar-isoscalar channel. We finally discuss the modification of the rho meson mass spectrum at finite density and/or temperature in connection with relativistic heavy ion collisions

  15. Extravasation of contrast medium during CT examination: An ...

    African Journals Online (AJOL)

    Introduction: extravasation is an adverse reaction to intravenous injection of contrast medium (CM) during CT examination. The objectives of this study are to determine the frequency, management and outcomes of extravasations and to assess risk factors for extravasation. Methods: every incident of extravasation which ...

  16. Measurement of Ground Electrical Conductivity for Planning Medium ...

    African Journals Online (AJOL)

    Results of propagation measurements are often required to improve the coverage of Medium Frequency (MF) broadcast transmitters. To achieve this, ground electrical conductivity measurement is one of the parameters often determined. In this study, ground conductivity has been measured around MF radio transmitters in ...

  17. Differential Medium for Vibrio cholerae

    Science.gov (United States)

    Schrank, Gordon D.; Stager, Charles E.; Verwey, W. F.

    1973-01-01

    A differential medium designed for rapid presumptive identification of Vibrio cholerae was described and shown to be useful for enumeration of viable cholera vibrios in the presence of other intestinal bacteria. Images PMID:4764406

  18. Medium effects in direct reactions

    International Nuclear Information System (INIS)

    Karakoc, M; Bertulani, C

    2013-01-01

    We discuss medium corrections of the nucleon-nucleon (NN) cross sections and their influence on direct reactions at intermediate energies ≳50 MeV/nucleon. The results obtained with free NN cross sections are compared with those obtained with a geometrical treatment of Pauli-blocking and Dirac-Bruecker methods. We show that medium corrections may lead to sizable modifications for collisions at intermediate energies and that they are more pronounced in reactions involving weakly bound nuclei.

  19. Conversion frequence

    International Nuclear Information System (INIS)

    Sauteret, C.

    1987-03-01

    The experimental evidence of short wavelength for laser inertial confinement has strongly increased the interest in high efficiency harmonic conversion of powerful Nd: glass lasers. This work describes our high power harmonic conversion experiments performed using the same laser apparatus for doubling, tripling the three high power 1064 nm P102, OCTAL and PHEBUS lasers. In addition to the understanding the physics of harmonic conversion, this work includes the basic concepts allows us to improve the technique such as non colinear schemes, to extend this method to other frequencies (fourth generation) and to predict some physical limits [fr

  20. Linear analysis of active-medium two-beam accelerator

    Directory of Open Access Journals (Sweden)

    Miron Voin

    2015-07-01

    Full Text Available We present detailed development of the linear theory of wakefield amplification by active medium and its possible application to a two-beam accelerator (TBA is discussed. A relativistic train of triggering microbunches traveling along a vacuum channel in an active medium confined by a cylindrical waveguide excites Cherenkov wake in the medium. The wake is a superposition of azimuthally symmetric transverse magnetic modes propagating along a confining waveguide, with a phase velocity equal to the velocity of the triggering bunches. The structure may be designed in such a way that the frequency of one of the modes is close to active-medium resonant frequency, resulting in amplification of the former and domination of a single mode far behind the trigger bunches. Another electron bunch placed in proper phase with the amplified wakefield may be accelerated by the latter. Importantly, the energy for acceleration is provided by the active medium and not the drive bunch as in a traditional TBA. Based on a simplified model, we analyze extensively the impact of various parameters on the wakefield amplification process.

  1. Chemistry of the interstellar medium

    International Nuclear Information System (INIS)

    Umanskij, S.Ya.

    1979-01-01

    Some aspects of chemistry of interstellar gas-dust clouds are considered. The specific attention is paid to the molecule formation in the interstellar medium. Discussed are the process of hydrogen atom recombination on interstellar specks of dust as well as the formation of double-atom molecules. An ion-molecular mechanism plays the main role in the origination of multiatom molecules. It is noted, that the real progress in chemistry of the interstellar medium will be determined by the development of laboratory investigations at ultralow temperatures and study of the processes proceeding on solid surfaces

  2. Medium-term fluctuations and the "Great Ratios" of economic growth

    DEFF Research Database (Denmark)

    Groth, Christian; Madsen, Jakob B.

    2016-01-01

    Evidence for the OECD countries show that the “great ratios”, such as the unemployment rate, factor shares, Tobin’s q and the investment-capital ratio, fluctuate significantly on medium-term frequencies of 10-40 years duration. To explain these medium-term fluctuations, we establish a macro-dynam...

  3. Medium-term Fluctuations and the 'Great Ratios' of Economic Growth

    DEFF Research Database (Denmark)

    Groth, Christian; Madsen, Jakob Brøchner

    Evidence for the OECD countries show that the “great ratios”, such as the unemployment rate, factor shares, Tobin’s q and the investment-capital ratio, fluctuate significantly on medium-term frequencies of 10-40 years duration. To explain these medium-term fluctuations, we establish a macro-dynam...

  4. Micropropagation of dahlia in static liquid medium using slow-release tools of medium ingredients

    NARCIS (Netherlands)

    Klerk, de G.J.M.; Brugge, ter J.

    2011-01-01

    Growth of dahlia shoots in vitro was ca. 4 times faster in liquid medium than on solidified medium. In liquid standard medium (3% sucrose, macroelements according to Driver–Kuniyuki Walnut medium, microelements according to Murashige–Skoog medium, 0.44 µM benzylaminopurine), the major medium

  5. Animal Locomotion in Different Mediums

    Indian Academy of Sciences (India)

    Wetlands are repositories of unique biodiversity. Wetlandorganisms are well adapted to their habitat, lying at theinterface of aquatic and terrestrial environments. In order tounderstand their adaptations in a better way, it is essential tograsp the basic properties of the medium in which variousorganisms live. This is attempted ...

  6. Animal Locomotion in Different Mediums

    Indian Academy of Sciences (India)

    IAS Admin

    Fishes, moving in water encounter drag forces, which can be of considerable magnitude. If sudden movement is required to catch prey or escape predators in a viscous medium, it is only possible by the contraction of fast, white muscle fibres, which rely on anaerobic glycolysis pathways. Therefore, it is not surprising that.

  7. Molecular spectroscopy of interstellar medium

    International Nuclear Information System (INIS)

    Varshalovich, D.A.; Khersonskij, V.K.

    1980-01-01

    Experimental data obtained in the investigation into molecules of interstellar medium by molecular-spectroscopic methods are discussed generally. Ion-molecule reactions play a significant part in the formation of multiatom molecules in the interstellar medium as well as reactions proceeding on the surface of interstellar dust. More than 50 types of molecules have been detected in the interstellar medium at present. In a wide range of wave lengths over 500 spectral lines belonging to various molecules and molecular fragments have been recorded. Interstellar molecules permit to investigate interstellar gas from all the sides. They are a suitable indicator of the isotope composition of interstellar gas. Radio observations of interstellar molecules make it possible to effectively investigate kinematics and space structure both separate gas-dust complexes and total gas distribution in Galaxy. It is noted that achievements of molecular spectroscopy of the interstellar medium radically change representations of the chemical composition of interstellar gas, of isotope abundance and organic substance in the Universe

  8. Hadron photoproduction at medium energy

    International Nuclear Information System (INIS)

    Dainton, J.B.

    1985-04-01

    Results from measurements of multibody photoproduction at medium incident photon energy (2.8 to 4.8 GeV) are presented and discussed. Particular emphasis is placed on topics which are not well understood and which therefore motivate experiments with the upgraded electron accelerator and storage ring ELSA at the University of Bonn, FR Germany. (author)

  9. Configural face encoding and spatial frequency information.

    Science.gov (United States)

    Boutet, Isabelle; Collin, Charles; Faubert, Jocelyn

    2003-10-01

    Configural relations and a critical band of spatial frequencies (SFs) in the middle range are particularly important for face recognition. We report the results of four experiments in which the relationship between these two types of information was examined. In Experiments 1, 2A, and 2B, the face inversion effect (FIE) was used to probe configural face encoding. Recognition of upright and inverted faces and nonface objects was measured in four conditions: a no-filter condition and three SF conditions (low, medium, and high frequency). We found significant FIEs of comparable magnitudes for all frequency conditions. In Experiment 3, discrimination of faces on the basis of either configural or featural modifications was measured under the same four conditions. Although the ability to discriminate configural modifications was superior in the medium-frequency condition, so was the ability to discriminate featural modifications. We conclude that the band of SF that is critical for face recognition does not contribute preferentially to configural encoding.

  10. On wave propagation in a random micropolar generalized thermoelastic medium

    Directory of Open Access Journals (Sweden)

    Mitra Manindra

    2017-06-01

    Full Text Available This paper endeavours to study aspects of wave propagation in a random generalized-thermal micropolar elastic medium. The smooth perturbation technique conformable to stochastic differential equations has been employed. Six different types of waves propagate in the random medium. The dispersion equations have been derived. The effects due to random variations of micropolar elastic and generalized thermal parameters have been computed. Randomness causes change of phase speed and attenuation of waves. Attenuation coefficients for high frequency waves have been computed. Second moment properties have been briefly discussed with application to wave propagation in the random micropolar elastic medium. Integrals involving correlation functions have been transformed to radial forms. A special type of generalized thermo-mechanical auto-correlation functions has been used to approximately compute effects of random variations of parameters. Uncoupled problem has been briefly outlined.

  11. Medium modifications with recoil polarization

    Energy Technology Data Exchange (ETDEWEB)

    Brand, J.F.J. van den [Nationaal Instituut voor Kernfysica en Hoge Energiefysica, Amsterdam (Netherlands); Ent, R. [CEBAF, Newport News, VA (United States)

    1994-04-01

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He({rvec e},e{prime},{rvec p}){sup 3}H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium.

  12. Medium modifications with recoil polarization

    International Nuclear Information System (INIS)

    Brand, J.F.J. van den; Ent, R.

    1994-01-01

    The authors show that the virtual Compton scattering process allows for a precise study of the off-shell electron-nucleon vertex. In a separable model, they show the sensitivity to new unconstrained structure functions of the nucleon, beyond the usual Dirac and Pauli form factors. In addition, they show the sensitivity to bound nucleon form factors using the reaction 4He(rvec e,e',rvec p) 3 H. A nucleon embedded in a nucleus represents a complex system. Firstly, the bound nucleon is necessarily off-shell and in principle a complete understanding of the dynamical structure of the nucleon is required in order to calculate its off-shell electromagnetic interaction. Secondly, one faces the possibility of genuine medium effects, such as for example quark-exchange contributions. Furthermore, the electromagnetic coupling to the bound nucleon is dependent on the nuclear dynamics through the self-energy of the nucleon in the nuclear medium

  13. The Spread of a Noise Field in a Dispersive Medium

    Directory of Open Access Journals (Sweden)

    Cohen Leon

    2010-01-01

    Full Text Available We discuss the production of induced noise by a pulse and the propagation of the noise in a dispersive medium. We present a simple model where the noise is the sum of pulses and where the mean of each pulse is random. We obtain explicit expressions for the standard deviation of the spatial noise as a function of time. We also formulate the problem in terms of a time-frequency phase space approach and in particular we use the Wigner distribution to define the spatial/spatial-frequency distribution.

  14. Probing the local interstellar medium

    International Nuclear Information System (INIS)

    Suess, S.T.; Dessler, A.J.

    1985-01-01

    The paper concerns the location of the heliospheric shock, in view of the discrepancy between the theoretical and experimental values. To determine whether the discrepancy may be attributed to parameters used to describe the local interstellar medium [LISM], the authors applied a sophisticated model of solar-wind expansion to deduce a range of parameters for the LISM. Both the interstellar magnetic field and the pressure due to galactic cosmic rays are considered. (U.K.)

  15. Explaining the gender difference in nightmare frequency.

    Science.gov (United States)

    Schredl, Michael

    2014-01-01

    A recent meta-analysis showed a robust gender difference in nightmare frequency of medium effect size in adolescents and young adults: Women tend to report nightmares more frequently than men. The present study, carried out in an unselected student sample, indicates that 2 factors mediate the gender difference in nightmare frequency: neuroticism and overall dream recall frequency. The effect of neuroticism on the gender difference and the finding that the gender difference in nightmare frequency emerges at an age of about 10 years suggest that gender-specific socialization processes may play an important role in explaining the gender differences in nightmare frequency in adolescents and young to middle-aged adults. This idea is supported by the previous finding that nightmare frequency is related to sex role orientation. However, longitudinal studies are necessary to validate these hypotheses.

  16. Medium Theory and Social Systems

    DEFF Research Database (Denmark)

    Tække, Jesper

    The  paper  first  gives  a  tentative  theoretical  explanation  of  the  concept  of media,  based  on  the  dichotomies  of  actual/potential  (meaning),  form/medium  (appearance),  and  substratum/material  content  (extension  in  time  and  space).  This  theoretical  explanation  presents......  seen as medium  for  formation. Finally  the  paper  takes  the micro  level  perspective  by  applying  the  theory  to  newsgroups,  interpreting  them as self-organizing interactive systems giving a differentiated and diversified scope for social  inclusion.  ......The  paper  first  gives  a  tentative  theoretical  explanation  of  the  concept  of media,  based  on  the  dichotomies  of  actual/potential  (meaning),  form/medium  (appearance),  and  substratum/material  content  (extension  in  time  and  space).  This  theoretical  explanation  presents......  the  possibility  for  observation both of a social micro and a social macro level from a medium perspective. In the next  section  the paper  frames  the macro  level by  a  tentative  synthesis of  the medium  theory  and  the  sociological systems theory briefly describing a socio...

  17. Room temperature microwave-assisted recording on 500-Gbpsi-class perpendicular medium

    Science.gov (United States)

    Nozaki, Y.; Ishida, N.; Soeno, Y.; Sekiguchi, K.

    2012-10-01

    Microwave-assisted recording on a 500-Gbpsi-class perpendicular medium was experimentally demonstrated at room temperature. Magnetization reversal under a radio-frequency magnetic field was measured by an electrically shorted coplanar waveguide, which enabled us to evaluate the change in the medium's ferromagnetic resonance spectrum. A frequency-dependent reduction in the switching field was clearly observed in response to a microwave impulse 50 ns in duration. A significant reduction of up to 30% in the coercive field was achieved by applying a microwave impulse with an amplitude of 25 dBm and a frequency of 15 GHz.

  18. Development of brachytherapy medium doserate

    International Nuclear Information System (INIS)

    Atang Susila; Ari Satmoko; Ahmad Rifai; Kristiyanti

    2010-01-01

    Brachytherapy has proven to be an effective treatment for different types of cancers and it become a common treatment modality in most radiotherapy clinics. PRPN has had experience in development of Low Dose Rate Brachytherapy for cervix cancer treatment. However the treatment process using LDR device needs 5 hours in time that the patient feel uncomfort. Therefore PRPN develops Medium Dose Rate Brachytherapy with radiation activity not more than 5 Currie. The project is divided into two stages. Purchasing of TPS software and TDS design are held in 2010, and the construction will be in 2011. (author)

  19. A Heterogeneous Medium Analytical Benchmark

    International Nuclear Information System (INIS)

    Ganapol, B.D.

    1999-01-01

    A benchmark, called benchmark BLUE, has been developed for one-group neutral particle (neutron or photon) transport in a one-dimensional sub-critical heterogeneous plane parallel medium with surface illumination. General anisotropic scattering is accommodated through the Green's Function Method (GFM). Numerical Fourier transform inversion is used to generate the required Green's functions which are kernels to coupled integral equations that give the exiting angular fluxes. The interior scalar flux is then obtained through quadrature. A compound iterative procedure for quadrature order and slab surface source convergence provides highly accurate benchmark qualities (4- to 5- places of accuracy) results

  20. Charmed hadrons in nuclear medium

    International Nuclear Information System (INIS)

    Tolos, L.; Gamermann, D.; Molina, R.; Nieves, J.; Oset, E.; Garcia-Recio, C.; Ramos, A.

    2010-01-01

    We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the D s0 (2317) and the predicted X(3700) scalar resonances. (authors)

  1. Effective Medium Theory for Anisotropic Metamaterials

    KAUST Repository

    Zhang, Xiujuan

    2017-11-12

    This dissertation includes the study of effective medium theories (EMTs) and their applications in describing wave propagation in anisotropic metamaterials, which can guide the design of metamaterials. An EMT based on field averaging is proposed to describe a peculiar anisotropic dispersion relation that is linear along the symmetry line but quadratic in the perpendicular direction. This dispersion relation is associated with the topological transition of the iso-frequency contours (IFCs), suggesting interesting wave propagation behaviors from beam shaping to beam splitting. In the framework of coherent potential approximation, an analytical EMT is further developed, with the ability to build a direct connection between the microscopic structure and the macroscopic material properties, which overcomes the requirement of prior knowledge of the field distributions. The derived EMT is valid beyond the long-wavelength limit. Using the EMT, an anisotropic zero-index metamaterial is designed. Moreover, the derived EMT imposes a condition that no scattered wave is generated in the ambient medium, which suggests the input signal cannot detect any object that might exist, making it invisible. Such correspondence between the EMT and the invisibilityinspires us to explore the wave cloaking in the same framework of coherent potential approximation. To further broaden the application realm of EMT, an EMT using the parameter retrieval method is studied in the regimes where the previously-developed EMTs are no longer accurate. Based on this study, in conjunction with the EMT mentioned above, a general scheme to realize coherent perfect absorption (CPA) in anisotropic metamaterials is proposed. As an exciting area in metamaterials, the field of metasurfaces has drawn great attention recently. As an easily attainable device, a grating may be the simplest version of metasurfaces. Here, an analytical EMT for gratings made of cylinders is developed by using the multiple scattering

  2. Electromagnetic wave propagation in a medium with a progressive sinusoidal fluctuation

    International Nuclear Information System (INIS)

    Ito, Hiroshi; Ito, Akinari

    1984-01-01

    Study was made on the rigorous solutions for electromagnetic waves transmitted and reflected by a medium of finite length with time-space periodic fluctuation, loaded in a rectangular waveguide. When an electromagnetic wave is incident upon the medium modulated in a travelling wave fashion by a pump wave, the reflected and transmitted waves are shifted in frequency by +nω 1 (where n is an integer, ω 1 is the angular frequency of fluctuation). The harmonic level of the reflected waves is much increased as the frequency of the incident wave approaches the cutoff-frequency of TE 10 mode of the rectangular waveguide. Measurement of the spectrum of the reflected waves can be utilized as a diagnosis of even a very slightly fluctuating medium. The theoretical results have been verified on examining experimentally the harmonic level of the microwave reflected by a plasma, weakly modulated (about 10 -4 ) by RF signal and loaded in the WRJ-10 waveguide. (author)

  3. Saliva as a diagnostic medium.

    Science.gov (United States)

    Pink, Richard; Simek, Jiri; Vondrakova, Jana; Faber, Edgar; Michl, Petr; Pazdera, Jindrich; Indrak, Karel

    2009-06-01

    This is a review of current knowledge on the use of saliva, gingival cervical fluid and mucosal transudate in the detection of some oral and systemic diseases as well as drugs. Oral fluid is a diagnostic medium that can be easily collected and with minimal invasion but it has been neglected in the past. Today, saliva is being used more often to diagnose: HIV virus, oro-facial and systemic tumors, cardiovascular disease and in detecting addictive substances. Neutropil levels in saliva may also indicate successful bone marrow transplant. Oral fluid is now systematically being researched and oral fluid analysis is being compared with the analysis of other diagnostic media such as blood and urine. A number of recent studies have focused on oncogenic marker detection and its monitoring in saliva. The latest clinical and laboratory findings on diagnostic markers of oropharyngeal carcinoma in oral fluid could be the beginning of their wider use as a diagnostic medium. Oral fluid can also be also used to diagnose other malignancies such as breast cancer which was one of the first malignant tumors to be detected using genetic protein biomarkers. Raised levels of CA15-3 and the epidermal growth factor (EGF) receptor have been found in patients with breast cancer and elevated levels of CA 125 and the glycoprotein complex in the saliva of ovarian cancer patients. Doubtless, the diagnostic value of saliva, aided by current technological development will increase rapidly in the near future.

  4. Unsaturated medium hydrocarbons pollution evaluation

    International Nuclear Information System (INIS)

    Di Luise, G.

    1991-01-01

    When the so called porous unsaturated medium, that's the vertical subsoil section between both the ground and water-table level, is interested by a hydrocarbons spill, the problem to evaluate the pollution becomes difficult: considering, essentially, the natural coexistence in it of two fluids, air and water, and the interactions between them. This paper reports that the problems tend to increase when a third fluid, the pollutant, immiscible with water, is introduced into the medium: a three-phases flow, which presents several analogies with the flow conditions present in an oil-reservoir, will be established. In such a situation, it would be very useful to handle the matter by the commonly used parameters in the oil reservoirs studies such as: residual saturation, relative permeability, phases mobility, to derive a first semiquantitative estimation of the pollution. The subsoil pollution form hydrocarbons agents is one of the worldwide more diffused causes of contamination: such events are generally referable to two main effects: accidental (oil pipeline breakdowns, e.g.), and continuous (underground tanks breaks, industrial plants leakages, e.g.)

  5. NEW RSW & Wall Medium Fully Tetrahedral Grid

    Data.gov (United States)

    National Aeronautics and Space Administration — New Medium Fully Tetrahedral RSW Grid with viscous wind tunnel wall at the root. This grid is for a node-based unstructured solver. Medium Tet: Quad Surface Faces= 0...

  6. Frequency noise in frequency swept fiber laser

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-01-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto...

  7. Mapping of moveout in a TTI medium

    KAUST Repository

    Stovas, A.

    2012-01-01

    To compute moveout in a transversely isotropic medium with tilted symmetry axis is a very complicated problem. We propose to split this problem into two parts. First, to compute the moveout in a corresponding VTI medium. Second, to map the computed moveout to a TTI medium.

  8. 27 CFR 19.914 - Medium plants.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Medium plants. 19.914... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Distilled Spirits For Fuel Use Permits § 19.914 Medium plants. Any person wishing to establish a medium plant shall make application for and obtain in...

  9. Optimization of medium composition for apple rootstocks

    African Journals Online (AJOL)

    User

    2011-05-02

    May 2, 2011 ... work of MS medium was also empirical and was deve- loped to optimise the mineral composition of the medium for growth of tobacco callus. A subsequent development such as Woody Plant Medium (WPM) (Lloyd and. McCown, 1981) was based on this previous process. 6-Benzylaminopurine (BA) and ...

  10. Coal char oxidation kinetics in air medium

    Directory of Open Access Journals (Sweden)

    Korotkikh Alexander G.

    2017-01-01

    Full Text Available Study of oxidation kinetics for three types of coal char with different carbon content in air is presented. The coal char powders of anthracite, bituminous T-grade coal and 2B-grade lignite with particle size less than 80 μm were tested. The coal char oxidation was researched by isothermal method via simultaneous TG-DSC analyzer Netzsch STA 449 Jupiter F3 in the temperature range of 1000–1200 °C. Measurements were carried out at ambient pressure. Volumetric flow rate of oxidizing medium into analyser chamber was 250 ml/min. Flow consisted of air and argon with volumetric ratio 24/1. Carbon average rate of oxidation reaction at each temperature were defined based on experimental results. Kinetic constants (the frequency factor and activation energy were defined for Arrhenius equation modified with three submodels: volumetric model, shrinking core model and random pore model. The activation energy values for anthracite are 1,6-1,7 times higher than for chars of bituminous coal and lignite.

  11. Medium-size nuclear plants

    International Nuclear Information System (INIS)

    Vogelweith, L.; Lavergne, J.C.; Martinot, G.; Weiss, A.

    1977-01-01

    CEA (TECHNICATOME) has developed a range of pressurized water reactors of the type ''CAS compact'' which are adapted to civil ship propulsion, or to electric power production, combined possibly with heat production, up to outputs equivalent to 125 MWe. Nuclear plants equipped with these reactors are suitable to medium-size electric networks. Among the possible realizations, two types of plants are mentioned as examples: 1) Floating electron-nuclear plants; and 2) Combined electric power and desalting plants. The report describes the design characteristics of the different parts of a 125 MWe unit floating electro-nuclear plant: nuclear steam system CAS 3 G, power generating plant, floating platform for the whole plant. The report gives attention to the different possibilities according to site conditions (the plant can be kept floating, in a natural or artificial basin, it can be put aground, ...) and to safety and environment factors. Such unit can be used in places where there is a growing demand in electric power and fresh water. The report describes how the reactor, the power generating plant and multiflash distillation units of an electric power-desalting plant can be combined: choice of the ratio water output/electric power output, thermal cycle combination, choice of the gain ratio, according to economic considerations, and to desired goal of water output. The report analyses also some technical options, such as: choice of the extraction point of steam used as heat supply of the desalting station (bleeding a condensation turbine, or recovering steam at the exhaust of a backpressure turbine), design making the system safe. Lastly, economic considerations are dealt with: combining the production of fresh water and electric power provides usually a much better energy balance and a lower cost for both products. Examples are given of some types of installations which combine medium-size reactors with fresh water stations yielding from 10000 to 120000 m 3 per day

  12. Traceable measurement of soft magnetic materials at high frequencies

    CERN Document Server

    Hall, M J; Henderson, L C A

    2000-01-01

    Whilst written EN standards already exist for traceable magnetic measurements at low and medium frequencies, extending these to frequencies up to 100 kHz and higher requires rigorous investigation of various additional factors. These are considered in this paper and results showing the importance of the winding configuration and the difficulty in defining the temperature of measurement presented.

  13. Tattoo: a multifaceted medium of communication

    Directory of Open Access Journals (Sweden)

    Christian Wymann

    2010-11-01

    Full Text Available This article suggests the systems theoretical distinction of form/medium as a useful tool for distinguishing social phenomena that might look as if they stem from the same process. This is shown to be the case for the tattoo and tattooing. The tattoo is conceived as a medium of communication through which different forms of communication emerge. Tattooing is one of these forms of communication that shapes the medium in a particular way. The current article sheds a special light on its intricate, communicational constellation, for which the concept of parallax is suggested. Law, medicine and cosmetics as other forms of communication use the medium of tattoo in their own way as well. The form/medium distinction allows us to grasp these different forms of communication, while it shows that they share the tattoo as medium. The article’s ultimate goal is to illustrate that the tattoo figures as a multifaceted medium of communication.

  14. High-frequency homogenization of zero frequency stop band photonic and phononic crystals

    CERN Document Server

    Antonakakis, Tryfon; Guenneau, Sebastien

    2013-01-01

    We present an accurate methodology for representing the physics of waves, for periodic structures, through effective properties for a replacement bulk medium: This is valid even for media with zero frequency stop-bands and where high frequency phenomena dominate. Since the work of Lord Rayleigh in 1892, low frequency (or quasi-static) behaviour has been neatly encapsulated in effective anisotropic media. However such classical homogenization theories break down in the high-frequency or stop band regime. Higher frequency phenomena are of significant importance in photonics (transverse magnetic waves propagating in infinite conducting parallel fibers), phononics (anti-plane shear waves propagating in isotropic elastic materials with inclusions), and platonics (flexural waves propagating in thin-elastic plates with holes). Fortunately, the recently proposed high-frequency homogenization (HFH) theory is only constrained by the knowledge of standing waves in order to asymptotically reconstruct dispersion curves an...

  15. Medium-Based Design: Extending a Medium to Create an Exploratory Learning Environment

    Science.gov (United States)

    Rick, Jochen; Lamberty, K. K.

    2005-01-01

    This article introduces "medium-based" design -- an approach to creating "exploratory learning environments" using the method of "extending a medium". First, the characteristics of exploratory learning environments and medium-based design are described and grounded in related work. Particular attention is given to "extending a medium" --…

  16. Dreams of a New Medium

    Directory of Open Access Journals (Sweden)

    Aden Evens

    2009-01-01

    Full Text Available Problematic at best, the desire for a transparent interface nevertheless drives much of digital culture and technology. But not the Web; or at least, not Web 1.0. Thoroughly commercialized, comfortably parsed into genres, serving billions of pages of predigested content to passive consumers, the World Wide Web as developed in the '90s unabashedly embraces its role as medium. While so many digital technologies work to hide their mediacy--drawing in the user with a total simulated sensorium, dematerializing the resistances of size and weight, untangling the knots of cables tying user to machine and machine to cubicle, minimizing the interface--Web 1.0 proudly clings to the browser as a glaring reminder of its medial character. While Web 2.0 has not forsaken the browser altogether, it nevertheless seems to offer a different sort of mediation. Arising alongside the atomization of browser functions, the ubiquitization of connectivity, and the coincidence of producer and user, Web 2.0 retains the form of a medium while reaching for the experiential logic of immediacy. This is not the immediacy of the transparent interface; rather, Web 2.0 effects an immediate relationship between the individual and culture. The interface does not disappear, but its mediacy is subsumed under the general form of cultural participation. Focusing on the "version upgrade" from Web 1.0 to 2.0, this essay will explore the implications for mediacy of this transition, noting that the fantasy of immediacy which drives Web 2.0 is layered and complex. The typical account of immediacy proposes to eliminate the interface and so construct a virtual reality (VR. But Web 2.0 mostly sidesteps the virtual, propelled instead by a fantasy of intuition in which the Web already knows what you want because it is you. Crucially, fantasies about the digital are effective: the computer's futurity inhabits our world, finding its expression in politics, advertising, budgeting, strategic planning

  17. Dust in the interplanetary medium

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Ingrid; Lamy, Herve [Belgian Institute for Space Aeronomy, Brussels (Belgium); Czechowski, Andrzej [Space Research Center, Polish Academy of Sciences, Warsaw (Poland); Meyer-Vernet, Nicole; Zaslavsky, Arnaud, E-mail: ingrid.mann@aeronomie.b [LESIA, Observatoire de Paris, Meudon (France)

    2010-12-15

    The mass density of dust particles that form from asteroids and comets in the interplanetary medium of the solar system is, near 1 AU, comparable to the mass density of the solar wind. It is mainly contained in particles of micrometer size and larger. Dust and larger objects are destroyed by collisions and sublimation and hence feed heavy ions into the solar wind and the solar corona. Small dust particles are present in large number and as a result of their large charge to mass ratio deflected by electromagnetic forces in the solar wind. For nanodust particles of sizes {approx_equal}1-10 nm, recent calculations show trapping near the Sun and outside from about 0.15 AU ejection with velocities close to solar wind velocity. The fluxes of ejected nanodust are detected near 1 AU with the plasma wave instrument onboard the STEREO spacecraft. Although such electric signals have been observed during dust impacts before, the interpretation depends on several different parameters and data analysis is still in progress.

  18. Studies in medium energy physics

    International Nuclear Information System (INIS)

    Green, A.; Hoffmann, G.W.; McDonough, J.; Purcell, M.J.; Ray, R.L.; Read, D.E.; Worn, S.D.

    1991-12-01

    This document constitutes the (1991--1992) technical progress report and continuation proposal for the ongoing medium energy nuclear physics research program supported by the US Department of Energy through special Research Grant DE-FG05-88ER40444. The experiments discussed are conducted at the Los Alamos National Laboratory's (LANL) Clinton P. Anderson Meson Physics Facility (LAMPF) and the Alternating Gradient Synchrotron (AGS) facility of the Brookhaven National Laboratory (BNL). The overall motivation for the work discussed in this document is driven by three main objectives: (1) provide hadron-nucleon and hadron-nucleus scattering data which serve to facilitate the study of effective two-body interactions, test (and possibly determine) nuclear structure, and help study reaction mechanisms and dynamics; (2) provide unique, first-of-a-kind ''exploratory'' hadron-nucleus scattering data in the hope that such data will lead to discovery of new phenomena and new physics; and (3) perform precision tests of fundamental interactions, such as rare decay searches, whose observation would imply fundamental new physics

  19. The interstellar medium in galaxies

    CERN Document Server

    1997-01-01

    It has been more than five decades ago that Henk van de Hulst predicted the observability of the 21-cm line of neutral hydrogen (HI ). Since then use of the 21-cm line has greatly improved our knowledge in many fields and has been used for galactic structure studies, studies of the interstellar medium (ISM) in the Milky Way and other galaxies, studies of the mass distribution of the Milky Way and other galaxies, studies of spiral struc­ ture, studies of high velocity gas in the Milky Way and other galaxies, for measuring distances using the Tully-Fisher relation etc. Regarding studies of the ISM, there have been a number of instrumen­ tal developments over the past decade: large CCD's became available on optical telescopes, radio synthesis offered sensitive imaging capabilities, not only in the classical 21-cm HI line but also in the mm-transitions of CO and other molecules, and X-ray imaging capabilities became available to measure the hot component of the ISM. These developments meant that Milky Way was n...

  20. LIGHT ABERRATION IN OPTICAL ANISOTROPIC SINGLE-AXIS MEDIUM

    Directory of Open Access Journals (Sweden)

    V. M. Svishch

    2017-10-01

    Full Text Available The entrainment of the light flux by a uniaxial anisotropic medium and its influence on the measurement of stellar aberration are analyzed. The influence of the entrainment of the light flux by an isotropic medium on the measurement of stellar aberration was considered by Fresnel early. The absence of such influence was confirmed by Erie's experience when filling the telescope tube with water. The formula itself was perfectly confirmed by Fizeau's experiments with moving water and the repetition of this experiment with an increase in the accuracy of measurements by Michelson, Zeeman, and others. G.A. Lorentz already on the basis of the electromagnetic theory specified the formula with allowance for the frequency dispersion of the light flux. A. Einstein made an analysis of the schemes of experiments for determining the drag coefficient, covering all possible variants of similar experiments. As a result, he obtained Fresnel and Lorentz formulas, taking into account the frequency dispersion of light, starting from the theory of relativity. The entrainment of light and its influence on the measurement of stellar aberration by a uniaxial anisotropic medium have not been considered anywhere. An analysis of such influence is carried out. The results of the analysis indicate the possibility of measuring the current value of stellar aberration using a uniaxial anisotropic medium. The concept of active light aberration is introduced. The proposed schemes of experiments of using the entrainment of a light flux by an anisotropic substance for measuring the current value of stellar aberration are investigated. It is concluded that it is possible to study the determination of the current velocity of an inertial system relative to the light flux.

  1. Multiple Frequency Parametric Sonar

    Science.gov (United States)

    2015-09-28

    300003 1 MULTIPLE FREQUENCY PARAMETRIC SONAR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...a method for increasing the bandwidth of a parametric sonar system by using multiple primary frequencies rather than only two primary frequencies...2) Description of Prior Art [0004] Parametric sonar generates narrow beams at low frequencies by projecting sound at two distinct primary

  2. Medium of Instruction in Thai Science Learning

    Science.gov (United States)

    Chanjavanakul, Natpat

    The goal of this study is to compare classroom discourse in Thai 9th grade science lessons with English or Thai as a medium of instruction. This is a cross-sectional study of video recordings from five lessons in an English-medium instruction class and five lessons in a Thai- medium instruction class from a Thai secondary school. The study involved two teachers and two groups of students. The findings show the use of both English and Thai in English-medium lessons. Students tend to be more responsive to teacher questions in Thai than in English. The findings suggest the use of students' native language during English-medium lessons to help facilitate learning in certain situations. Additionally, the study provides implications for research, practice and policy for using English as a medium of instruction.

  3. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  4. Optical illusions induced by rotating medium

    Science.gov (United States)

    Zang, XiaoFei; Huang, PengCheng; Zhu, YiMing

    2018-03-01

    Different from the traditional single-function electromagnetic wave rotators (rotate the electromagnetic wavefronts), we propose that rotating medium can be extended to optical illusions such as breaking the diffraction limit and overlapping illusion. Furthermore, the homogeneous but anisotropic rotating medium is simplified by homogeneous and isotropic positive-index materials according to the effective medium theory, which is helpful for future device fabrication. Finite element simulations for the two-dimensional case are performed to demonstrate these properties.

  5. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences...

  6. Surface modes of two spheres embedded into a third medium

    International Nuclear Information System (INIS)

    Nkoma, J.S.

    1990-07-01

    Surface modes of two spheres embedded into a third medium are studied. We obtain a result which relates the dependence of frequency on the distance between the two spheres. The derived expression reproduces previous results in the limit where the separation between the spheres is very large. Two surface mode branches are shown to exist for each order n. We apply the theory to three cases of practical interest: first, two similar metallic spheres in vacuum; secondly, two similar metallic spheres embedded into a different metal; thirdly, two spherical voids embedded into a metal. (author). 19 refs, 6 figs

  7. Chemically defined medium and Caenorhabditis elegans

    Science.gov (United States)

    Szewczyk, Nathaniel J.; Kozak, Elena; Conley, Catharine A.

    2003-01-01

    BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  8. High Frequency Guided Wave Virtual Array SAFT

    Science.gov (United States)

    Roberts, R.; Pardini, A.; Diaz, A.

    2003-03-01

    The principles of the synthetic aperture focusing technique (SAFT) are generalized for application to high frequency plate wave signals. It is shown that a flaw signal received in long-range plate wave propagation can be analyzed as if the signals were measured by an infinite array of transducers in an unbounded medium. It is shown that SAFT-based flaw sizing can be performed with as few as three or less actual measurement positions.

  9. Thermo-mechanical vibration analysis of annular and circular graphene sheet embedded in an elastic medium

    Directory of Open Access Journals (Sweden)

    M. Mohammadi

    Full Text Available In this study, the vibration behavior of annular and circular graphene sheet coupled with temperature change and under in-plane pre-stressed is studied. Influence of the surrounding elastic medium 011 the fundamental frequencies of the single-layered graphene sheets (SLGSs is investigated. Both Winkler-type and Pasternak- type models are employed to simulate the interaction of the graphene sheets with a surrounding elastic medium. By using the nonlocal elasticity theory the governing equation is derived for SLGSs. The closed-form solution for frequency vibration of circular graphene sheets lias been obtained and nonlocal parameter, inplane pre-stressed, the parameters of elastic medium and temperature change appears into arguments of Bessel functions. The results are subsequently compared with valid result reported in the literature and the molecular dynamics (MD results. The effects of the small scale, pre-stressed, mode number, temperature change, elastic medium and boundary conditions on natural frequencies are investigated. The non-dimensional frequency decreases at high temperature case with increasing the temperature change for all boundary conditions. The effect of temperature change 011 the frequency vibration becomes the opposite at high temperature case in compression with the low temperature case. The present research work thus reveals that the nonlocal parameter, boundary conditions and temperature change have significant effects on vibration response of the circular nanoplates. The present results can be used for the design of the next generation of nanodevices that make use of the thermal vibration properties of the graphene.

  10. 49 CFR 236.811 - Speed, medium.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Speed, medium. 236.811 Section 236.811 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Speed, medium. A speed not exceeding 40 miles per hour. ...

  11. English Medium of Instruction: A Situation Analysis

    Science.gov (United States)

    Uys, Mandie; van der Walt, Johann; van den Berg, Ria; Botha, Sue

    2007-01-01

    The majority of learners in southern Africa receive their education through the medium of a second language, English. Although teachers of English play a crucial role in helping learners to acquire language skills in the medium of instruction, we argue that subject content teachers' lack of attention to the teaching of the four language skills may…

  12. Electromagnetic Sources in a Moving Conducting Medium

    DEFF Research Database (Denmark)

    Johannsen, Günther

    1971-01-01

    The problem of an arbitrary source distribution in a uniformly moving, homogeneous, isotropic, nondispersive, conducting medium is solved. The technique used is to solve the problem in the rest system of the medium and then write the result in an appropriate four-dimensional, covariant form which...

  13. Effective medium theory for anisotropic metamaterials

    KAUST Repository

    Zhang, Xiujuan

    2015-01-20

    Materials with anisotropic material parameters can be utilized to fabricate many fascinating devices, such as hyperlenses, metasolids, and one-way waveguides. In this study, we analyze the effects of geometric anisotropy on a two-dimensional metamaterial composed of a rectangular array of elliptic cylinders and derive an effective medium theory for such a metamaterial. We find that it is possible to obtain a closed-form analytical solution for the anisotropic effective medium parameters, provided the aspect ratio of the lattice and the eccentricity of the elliptic cylinder satisfy certain conditions. The derived effective medium theory not only recovers the well-known Maxwell-Garnett results in the quasi-static regime, but is also valid beyond the long-wavelength limit, where the wavelength in the host medium is comparable to the size of the lattice so that previous anisotropic effective medium theories fail. Such an advance greatly broadens the applicable realm of the effective medium theory and introduces many possibilities in the design of structures with desired anisotropic material characteristics. A real sample of a recently theoretically proposed anisotropic medium, with a near-zero index to control the flux, is achieved using the derived effective medium theory, and control of the electromagnetic waves in the sample is clearly demonstrated.

  14. Optimization of medium composition for thermostable protease ...

    African Journals Online (AJOL)

    SERVER

    2008-04-17

    Apr 17, 2008 ... Optimization of the fermentation medium for maximization of thermostable neutral protease production by Bacillus sp. ... at 3.6 g/l and yeast extract at 3.9 g/l gived maximum protease activity of 6804 U/ml. Key words: Medium ... face method, which is used to study the effects of several factors influencing the ...

  15. Frequency dependence of sonophoresis.

    Science.gov (United States)

    Tezel, A; Sens, A; Tuchscherer, J; Mitragotri, S

    2001-12-01

    Application of low-frequency ultrasound has been shown to increase skin permeability, thereby facilitating delivery of macromolecules (low-frequency sonophoresis). In this study, we sought to determine the dependence of low-frequency sonophoresis on ultrasound frequency, intensity and energy density. Pig skin was exposed to low-frequency ultrasound over a range of ultrasound frequency and intensity conditions. The degree of skin permeabilization was measured using its conductivity. Imaging experiments were also carried out to visualize the transport pathways created by ultrasound. The data showed that for each frequency (in the range of 19.6-93.4 kHz), there exists a threshold intensity below which no detectable conductivity enhancement was observed. The threshold intensity increased with frequency. It is feasible to achieve the desired conductivity (permeability) enhancement regardless of the choice of frequency, although the necessary energy density is higher at higher frequencies. Low frequencies (approximately 20 kHz) induced localized transport compared to a more dispersed effect seen with higher frequencies (approximately 58.9 kHz). This study provides a quantitative understanding of the effects of low-frequency ultrasound on skin permeability.

  16. Optical bistability induced by quantum coherence in a negative index atomic medium

    International Nuclear Information System (INIS)

    Zhang Hong-Jun; Sun Hui; Li Jin-Ping; Yin Bao-Yin; Guo Hong-Ju

    2013-01-01

    Bistability behaviors in an optical ring cavity filled with a dense V-type four-level atomic medium are theoretically investigated. It is found that the optical bistability can appear in the negative refraction frequency band, while both the bistability and multi-stability can occur in the positive refraction frequency bands. Therefore, optical bistability can be realized from conventional material to negative index material due to quantum coherence in our scheme. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. Stoneley waves in a non-homogeneous orthotropic granular medium under the influence of gravity

    Directory of Open Access Journals (Sweden)

    S. M. Ahmed

    2005-01-01

    Full Text Available The aim of this paper is to investigate the Stoneley waves in a non-homogeneous orthotropic granular medium under the influence of a gravity field. The frequency equation obtained, in the form of a sixth-order determinantal expression, is in agreement with the corresponding result when both media are elastic. The frequency equation when the gravity field is neglected has been deduced as a particular case.

  18. Lunch frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Krølner, Rikke

    2016-01-01

    OBJECTIVE: To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch...

  19. Micropropagation of Alstroemeria in liquid medium using slow release of medium components

    NARCIS (Netherlands)

    Klerk, de G.J.M.; Brugge, ter J.

    2010-01-01

    Alstroemeria rhizomes were micropropagated on semi-solid medium (AM) and in liquid medium (LM). In LM, growth was much enhanced (ca. 70%). Adequate gas exchange was crucial. This was obtained by agitation and in static medium by a sufficient large contact area of the explant and the gaseous

  20. Modeling Frequency Comb Sources

    Directory of Open Access Journals (Sweden)

    Li Feng

    2016-06-01

    Full Text Available Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  1. Frequency reference in VSAT

    Science.gov (United States)

    Cheah, Jonathon Y. C.

    1994-02-01

    A low cost technique of frequency reference distribution within a VSAT network is discussed. This technique allows the use of a modestly frequency stable oscillator as the master frequency reference in the hub of a star-connected VSAT network. The need for extremely frequency stable OCXOs in VSATs is completely avoided. This technique was successfully incorporated in the early commercial VSAT networks. It contributes partially to the low cost nature of some of the VSAT networks available today.

  2. Static electromagnetic frequency changers

    CERN Document Server

    Rozhanskii, L L

    1963-01-01

    Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

  3. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  4. Making Sense of Frequency.

    Science.gov (United States)

    Larsen-Freeman, Diane

    2002-01-01

    Responds to Ellis (2002), which focuses on frequency in language processing, language use, and language acquisition. Contextualizes the frequency factor in terms of the evolution of second language acquisition (SLA) research. Suggests that although relevant and important, the frequency factor requires greater definition and qualification.…

  5. Nonlocal vibration and biaxial buckling of double-viscoelastic-FGM-nanoplate system with viscoelastic Pasternak medium in between

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.C. [College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); Zhang, Y.Q., E-mail: cyqzhang@zju.edu.cn [College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058 (China); State Key Laboratory of Mechanical Structural Strength and Vibration, Xi' an Jiaotong University, Xi' an 710049 (China); Fan, L.F. [College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100084 (China)

    2017-04-11

    The general equation for transverse vibration of double-viscoelastic-FGM-nanoplate system with viscoelastic Pasternak medium in between and each nanoplate subjected to in-plane edge loads is formulated on the basis of the Eringen's nonlocal elastic theory and the Kelvin model. The factors of the structural damping, medium damping, small size effect, loading ratio, and Winkler modulus and shear modulus of the medium are incorporated in the formulation. Based on the Navier's method, the analytical solutions for vibrational frequency and buckling load of the system with simply supported boundary conditions are obtained. The influences of these factors on vibrational frequency and buckling load of the system are discussed. It is demonstrated that the vibrational frequency of the system for the out-of-phase vibration is dependent upon the structural damping, small size effect and viscoelastic Pasternak medium, whereas the vibrational frequency for the in-phase vibration is independent of the viscoelastic Pasternak medium. While the buckling load of the system for the in-phase buckling case has nothing to do with the viscoelastic Pasternak medium, the buckling load for the out-of-phase case is related to the small size effect, loading ratio and Pasternak medium. - Highlights: • Vibration of double-viscoelastic-FGM-nanoplate system under in-plane edge loads is investigated. • Biaxial buckling of the system with simply supported boundary conditions is analyzed. • Explicit expression for the vibrational frequency and buckling load is obtained. • Impacts of viscoelastic Pasternak medium on vibrational frequency and buckling load are discussed. • Influences of structural damping, small size effect and loading ratio are also considered.

  6. Collaborative Manufacturing for Small-Medium Enterprises

    Science.gov (United States)

    Irianto, D.

    2016-02-01

    Manufacturing systems involve decisions concerning production processes, capacity, planning, and control. In a MTO manufacturing systems, strategic decisions concerning fulfilment of customer requirement, manufacturing cost, and due date of delivery are the most important. In order to accelerate the decision making process, research on decision making structure when receiving order and sequencing activities under limited capacity is required. An effective decision making process is typically required by small-medium components and tools maker as supporting industries to large industries. On one side, metal small-medium enterprises are expected to produce parts, components or tools (i.e. jigs, fixture, mold, and dies) with high precision, low cost, and exact delivery time. On the other side, a metal small- medium enterprise may have weak bargaining position due to aspects such as low production capacity, limited budget for material procurement, and limited high precision machine and equipment. Instead of receiving order exclusively, a small-medium enterprise can collaborate with other small-medium enterprise in order to fulfill requirements high quality, low manufacturing cost, and just in time delivery. Small-medium enterprises can share their best capabilities to form effective supporting industries. Independent body such as community service at university can take a role as a collaboration manager. The Laboratory of Production Systems at Bandung Institute of Technology has implemented shared manufacturing systems for small-medium enterprise collaboration.

  7. Physical processes in the interstellar medium

    CERN Document Server

    Spitzer, Lyman

    2008-01-01

    Physical Processes in the Interstellar Medium discusses the nature of interstellar matter, with a strong emphasis on basic physical principles, and summarizes the present state of knowledge about the interstellar medium by providing the latest observational data. Physics and chemistry of the interstellar medium are treated, with frequent references to observational results. The overall equilibrium and dynamical state of the interstellar gas are described, with discussions of explosions produced by star birth and star death and the initial phases of cloud collapse leading to star formation.

  8. Study of stratified dielectric slab medium structures using pseudo-spectral time domain (PSTD) algorithm

    DEFF Research Database (Denmark)

    Tong, M.S.; Lu, Y.; Chen, Y.

    2005-01-01

    A planar stratified dielectric slab medium, which is an interesting problem in optics and geophysics, is studied using a pseudo-spectral time-domain (PSTD) algorithm. Time domain electric fields and frequency domain propagation characteristics of both single and periodic dielectric slab...

  9. Study of stratified dielectric slab medium structures using pseudo-spectral time domain (PSTD) algorithm

    DEFF Research Database (Denmark)

    Tong, M.S.; Lu, Y.; Chen, Y.

    2005-01-01

    A planar stratified dielectric slab medium, which is an interesting problem in optics and geophysics, is studied using a pseudo-spectral time-domain (PSTD) algorithm. Time domain electric fields and frequency domain propagation characteristics of both single and periodic dielectric slab-layer str...

  10. A linear postaccelerator with superconducting helix resonators for medium mass ions

    International Nuclear Information System (INIS)

    Ingwersen, H.; Jaeschke, E.; Repnow, R.; Walcher, T.; Hochschild, G.; Lehmann, W.; Piosczyk, B.; Spath, F.; Vetter, J.E.

    1978-05-01

    The concept is presented of a linear accelerator equiped with short superconducting resonators as accelerating elements. Saving high-frequency power remarkably reduces the operating costs as compared with normal conducting resonators. Booster systems of this type can be used to further accelerate medium heavy ions having passed on MP tandem after their charge state has been increased. (orig.) 891 WL [de

  11. Lexical Bundles in Chinese Undergraduate Academic Writing at an English Medium University

    Science.gov (United States)

    Ruan, Zhoulin

    2017-01-01

    This paper investigates the use of lexical bundles in Chinese students' academic writing across different levels of studies at an English medium university. Frequency-based bundles were retrieved from a corpus of student academic texts written at four points of time between Year 1 and Year 4, and the structures and functions of the bundles were…

  12. RF Channel Characteristics of the Medium-voltage Power Line for PLC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.H. [Keochang Polytechnic College, Keochang (Korea); Kim, K.H. [Korea Electrotechnology Research Institute, Changwon (Korea); Rhee, Y.C. [Kyungnam University, Masan (Korea); Shin, C.C. [Ajou University, Suwon (Korea)

    2002-07-01

    In this paper, the channel characteristics of the medium voltage(22.9kV) power line to analysis the broadband power line communication in the frequency range up to 30MHz was measured. With the wideband electrical coupler in the operating frequency range from DC to 30MHz, we measured characteristic impedance, noise and attenuation of the medium voltage power line, and then characteristic impedance was measured at the state of unloaded medium voltage power line by Scattering parameter method of Vector Network Analyzer. As a measurement result, Channel impedance shows 100{approx}380{omega} at the less than 15MHz and 70{approx}230{omega} at the more than 15 MHz. Noise characteristics of power line shows -75dBm at 20MHz and Narrowband interference noise was from 3 MHz to 7 MHz. (author). 8 refs., 8 figs., 1 tab.

  13. Free vibration characteristics of double-walled carbon nanotubes embedded in an elastic medium

    International Nuclear Information System (INIS)

    Natsuki, Toshiaki; Lei, Xiao-Wen; Ni, Qing-Qing; Endo, Morinobu

    2010-01-01

    In this Letter, a theoretical analysis of the resonant vibration of double-walled carbon nanotubes (DWCNTs) and the DWCNTs embedded in an elastic medium is presented based on Euler-Bernoulli beam model and Winkler spring model. The vibration modes of DWCNTs are quite different from those of single-walled carbon nanotubes (SWCNTs). The resonant vibrations of DWCNTs are found to have in-phase and anti-phase modes, in which the deflections of the inner and outer nanotubes occur in the same and opposite directions, respectively. For the vibration of DWCNTs with the same harmonic numbers, the resonant frequencies of anti-phase mode are larger than the ones of in-phase mode. Moreover, influence of the surrounding medium on the resonant vibrations is investigated using the Winkler spring model. The results show that surrounding medium makes a strong impact on the vibration frequencies of in-phase mode, but little on those of anti-phase mode.

  14. Nucleon form factors in the nuclear medium

    Science.gov (United States)

    Park, Chanyong; Lee, Jung Hun

    2018-01-01

    By using the AdS/CFT correspondence, we investigate various form factors between nucleons and mesons in a nuclear medium. In order to describe a nuclear medium holographically, we take into account the thermal charged AdS geometry with an appropriate IR cutoff. After introducing an anomalous dimension as a free parameter, we investigate how the nucleon’s mass is affected by the change of the anomalous dimension. Moreover, we study how the form factors of nucleons rely on the properties of the nuclear medium. We show that in a nuclear medium with different numbers of proton and neutron, the degenerated nucleon form factor in the vacuum is split into four different values depending on the isospin charges of nucleon and meson.

  15. Study of niobium corrosion in alkaline medium

    International Nuclear Information System (INIS)

    Almeida, S.H. de.

    1987-01-01

    A comparative study of niobium electrochemical behaviour in NaOH and KOH solution, with concentrations between 0,5 and 6,1M is presented. The studies were done through electrochemicals assays, consisting in the corrosion potential and anodic and cathodic polarization curves, complemented by loss of mass experiments. The niobium anodic behaviour in alkaline medium is characterized by passivation occurrence, with a stable film formation. The Na oH solution in alkaline medium are more corrosible to niobium than the KOH solution. The loss of mass assays showed that the corrosion velocit is more dependente of hydroxide concentration in KOH medium than the NaOH medium. (C.G.C.) [pt

  16. Fractional diffusion equation for heterogeneous medium

    Energy Technology Data Exchange (ETDEWEB)

    Polo L, M. A.; Espinosa M, E. G.; Espinosa P, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Area de Ingenieria en Recursos Energeticos, Av, San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Del Valle G, E., E-mail: plabarrios@hotmail.com [Instituto Politecnico Nacional, Escuela Superior de Fisica y Matematicas, Av. IPN s/n, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico)

    2011-11-15

    The asymptotic diffusion approximation for the Boltzmann (transport) equation was developed in 1950 decade in order to describe the diffusion of a particle in an isotropic medium, considers that the particles have a diffusion infinite velocity. In this work is developed a new approximation where is considered that the particles have a finite velocity, with this model is possible to describe the behavior in an anomalous medium. According with these ideas the model was obtained from the Fick law, where is considered that the temporal term of the current vector is not negligible. As a result the diffusion equation of fractional order which describes the dispersion of particles in a highly heterogeneous or disturbed medium is obtained, i.e., in a general medium. (Author)

  17. (New molecular ions in the interstellar medium

    Directory of Open Access Journals (Sweden)

    Roueff Evelyne

    2015-01-01

    Full Text Available We summarize the present knowledge on the molecular ionic content in the interstellar medium and in circumstellar envelopes. Emphasis is given on the most recent detections and the related chemical issues.

  18. Small and medium power reactors 1987

    International Nuclear Information System (INIS)

    1987-12-01

    This TECDOC follows the publication of TECDOC-347 Small and Medium Power Reactors Project Initiation Study - Phase I published in 1985 and TECDOC-376 Small and Medium Power Reactors 1985 published in 1986. It is mainly intended for decision makers in Developing Member States interested in embarking on a nuclear power programme. It consists of two parts: 1) Guidelines for the Introduction of Small and Medium Power Reactors in Developing Countries. These Guidelines were established during the Advisory Group Meeting held in Vienna from 11 to 15 May 1987. Their purpose is to review key aspects relating to the introduction of Small and Medium Power Reactors in developing countries; 2) Up-dated Information on SMPR Concepts Contributed by Supplier Industries. According to the recommendations of the Second Technical Committee Meeting on SMPRs held in Vienna in March 1985, this part contains the up-dated information formerly published in Annex I of the above mentioned TECDOC-347. Figs

  19. Sharing perspectives on English-medium instruction

    CERN Document Server

    Ackerley, Katherine; Helm, Francesca

    2017-01-01

    This volume gives voice to the views and experiences of researchers, lecturers, administrative staff, teacher trainers and students with regard to the implementation of English-medium instruction in a public university based in the north-east of Italy.

  20. Effective medium theory principles and applications

    CERN Document Server

    Choy, Tuck C

    2015-01-01

    Effective medium theory dates back to the early days of the theory of electricity. Faraday in 1837 proposed one of the earliest models for a composite metal-insulator dielectric and around 1870 Maxwell and later Garnett (1904) developed models to describe a composite or mixed material medium. The subject has been developed considerably since and while the results are useful for predicting materials performance, the theory can also be used in a wide range of problems in physics and materials engineering. This book develops the topic of effective medium theory by bringing together the essentials of both the static and the dynamical theory. Electromagnetic systems are thoroughly dealt with, as well as related areas such as the CPA theory of alloys, liquids, the density functional theory etc., with applications to ultrasonics, hydrodynamics, superconductors, porous media and others, where the unifying aspects of the effective medium concept are emphasized. In this new second edition two further chapters have been...

  1. Medium Effects in Reactions with Rare Isotopes

    International Nuclear Information System (INIS)

    Bertulani, C A; Karakoç, M

    2012-01-01

    We discuss medium effects in knockout reactions with rare isotopes of weakly-bound nuclei at intermediate energies. We show that the poorly known corrections may lead to sizable modifications of knockout cross sections and momentum dsitributions.

  2. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  3. Graphene wire medium: Homogenization and application

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Chigrin, Dmitry N.; Lavrinenko, Andrei

    2012-01-01

    In this contribution we analyze numerically the optical properties of the graphene wire medium, which unit cell consists of a stripe of graphene embedded into dielectric. We propose a simple method for retrieval of the isofrequency contour and effective permittivity tensor. As an example...... of the graphene wire medium application we demonstrate a reconfigurable hyperlens for the terahertz subwavelength imaging capable of resolving two sources with separation λ0/5 in the far-field....

  4. Selective medium for culture of Mycoplasma hyopneumoniae.

    Science.gov (United States)

    Cook, Beth S; Beddow, Jessica G; Manso-Silván, Lucía; Maglennon, Gareth A; Rycroft, Andrew N

    2016-11-15

    The fastidious porcine respiratory pathogen Mycoplasma hyopneumoniae has proven difficult to culture since it was first isolated in 1965. A reliable solid medium has been particularly challenging. Moreover, clinical and pathological samples often contain the fast-growing M. hyorhinis which contaminates and overgrows M. hyopneumoniae in primary culture. The aim of this study was to optimise the culture medium for recovery of M. hyopneumoniae and to devise a medium for selection of M. hyopneumoniae from clinical samples also containing M. hyorhinis. The solid medium devised by Niels Friis was improved by use of Purified agar and incorporation of DEAE-dextran. Addition of glucose or neutralization of acidity in liquid medium with NaOH did not improve the final yield of viable organisms or alter the timing of peak viability. Analysis of the relative susceptibility of M. hyopneumoniae and M. hyorhinis strains to four antimicrobials showed that M. hyopneumoniae is less susceptible than M. hyorhinis to kanamycin. This was consistent in all UK and Danish strains tested. A concentration of 2μg/ml of kanamycin selectively inhibited the growth of all M. hyorhinis tested, while M. hyopneumoniae was able to grow. This forms the basis of an effective selective culture medium for M. hyopneumoniae. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Frequency mixing in boron carbide laser ablation plasmas

    Science.gov (United States)

    Oujja, M.; Benítez-Cañete, A.; Sanz, M.; Lopez-Quintas, I.; Martín, M.; de Nalda, R.; Castillejo, M.

    2015-05-01

    Nonlinear frequency mixing induced by a bichromatic field (1064 nm + 532 nm obtained from a Q-switched Nd:YAG laser) in a boron carbide (B4C) plasma generated through laser ablation under vacuum is explored. A UV beam at the frequency of the fourth harmonic of the fundamental frequency (266 nm) was generated. The dependence of the efficiency of the process as function of the intensities of the driving lasers differs from the expected behavior for four-wave mixing, and point toward a six-wave mixing process. The frequency mixing process was strongly favored for parallel polarizations of the two driving beams. Through spatiotemporal mapping, the conditions for maximum efficiency were found for a significant delay from the ablation event (200 ns), when the medium is expected to be a low-ionized plasma. No late components of the harmonic signal were detected, indicating a largely atomized medium.

  6. Radio frequency detection assembly and method for detecting radio frequencies

    Science.gov (United States)

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  7. Waveform frequency notching

    Science.gov (United States)

    Doerry, Armin W.; Andrews, John

    2017-05-09

    The various technologies presented herein relate to incorporating one or more notches into a radar spectrum, whereby the notches relate to one or more frequencies for which no radar transmission is to occur. An instantaneous frequency is monitored and if the frequency is determined to be of a restricted frequency, then a radar signal can be modified. Modification can include replacing the signal with a signal having a different instantaneous amplitude, a different instantaneous phase, etc. The modification can occur in a WFS prior to a DAC, as well as prior to a sin ROM component and/or a cos ROM component. Further, the notch can be dithered to enable formation of a deep notch. The notch can also undergo signal transitioning to enable formation of a deep notch. The restricted frequencies can be stored in a LUT against which an instantaneous frequency can be compared.

  8. LOW FREQUENCY DAMPER

    Directory of Open Access Journals (Sweden)

    Radu BOGATEANU

    2009-09-01

    Full Text Available The low frequency damper is an autonomous equipment for damping vibrations with the 1-20Hz range.Its autonomy enables the equipment to be located in various mechanical systems, without requiring special hydraulic installations.The low frequency damper was designed for damping the low frequency oscillations occurring in the circuit controls of the upgraded IAR-99 Aircraft.The low frequency damper is a novelty in the aerospace field ,with applicability in several areas as it can be built up in an appropriate range of dimensions meeting the requirements of different beneficiaries. On this line an equipment able to damp an extended frequency range was performed for damping oscillations in the pipes of the nuclear power plants.This damper, tested in INCAS laboratories matched the requirements of the beneficiary.The low frequency damper is patented – the patent no. 114583C1/2000 is held by INCAS.

  9. Frequency Response Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    Etingov, Pavel V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kosterev, Dmitry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dai, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

  10. Nonlinear Frequency Compression

    Science.gov (United States)

    Scollie, Susan; Glista, Danielle; Seelisch, Andreas

    2013-01-01

    Frequency lowering technologies offer an alternative amplification solution for severe to profound high frequency hearing losses. While frequency lowering technologies may improve audibility of high frequency sounds, the very nature of this processing can affect the perceived sound quality. This article reports the results from two studies that investigated the impact of a nonlinear frequency compression (NFC) algorithm on perceived sound quality. In the first study, the cutoff frequency and compression ratio parameters of the NFC algorithm were varied, and their effect on the speech quality was measured subjectively with 12 normal hearing adults, 12 normal hearing children, 13 hearing impaired adults, and 9 hearing impaired children. In the second study, 12 normal hearing and 8 hearing impaired adult listeners rated the quality of speech in quiet, speech in noise, and music after processing with a different set of NFC parameters. Results showed that the cutoff frequency parameter had more impact on sound quality ratings than the compression ratio, and that the hearing impaired adults were more tolerant to increased frequency compression than normal hearing adults. No statistically significant differences were found in the sound quality ratings of speech-in-noise and music stimuli processed through various NFC settings by hearing impaired listeners. These findings suggest that there may be an acceptable range of NFC settings for hearing impaired individuals where sound quality is not adversely affected. These results may assist an Audiologist in clinical NFC hearing aid fittings for achieving a balance between high frequency audibility and sound quality. PMID:23539261

  11. Frequency Selective Reflector Antenna

    Data.gov (United States)

    National Aeronautics and Space Administration — Frequency Selective Surfaces (FSS) are an electromagnetic structure where a relatively thin, periodic, conductive material is designed as a spatial filter of...

  12. Grid Filter Design for a Multi-Megawatt Medium-Voltage Voltage Source Inverter

    DEFF Research Database (Denmark)

    Rockhill, A.A.; Liserre, Marco; Teodorescu, Remus

    2011-01-01

    constraints. To achieve this goal, new concepts such as virtual harmonic content and virtual filter losses are introduced. Moreover, a new passive damping technique that provides the necessary damping with low losses and very little degradation of the high-frequency attenuation is proposed.......This paper describes the design procedure and performance of an LCL grid filter for a medium-voltage neutral point clamped (NPC) converter to be adopted for a multimegawatt wind turbine. The unique filter design challenges in this application are driven by a combination of the medium voltage...... converter, a limited allowable switching frequency, component physical size and weight concerns, and the stringent limits for allowable injected current harmonics. Traditional design procedures of grid filters for lower power and higher switching frequency converters are not valid for a multi...

  13. Evaluation of Insulin Medium or Chondrogenic Medium on Proliferation and Chondrogenesis of ATDC5 Cells

    OpenAIRE

    Yao, Yongchang; Zhai, Zhichen; Wang, Yingjun

    2014-01-01

    Background. The ATDC5 cell line is regarded as an excellent cell model for chondrogenesis. In most studies with ATDC5 cells, insulin medium (IM) was used to induce chondrogenesis while chondrogenic medium (CM), which was usually applied in chondrogenesis of mesenchymal stem cells (MSCs), was rarely used for ATDC5 cells. This study was mainly designed to investigate the effect of IM, CM, and growth medium (GM) on chondrogenesis of ATDC5 cells. Methods. ATDC5 cells were, respectively, cultured ...

  14. Frequency Mapping for the Operational Frequency Manager

    Science.gov (United States)

    2008-03-01

    and stationary computers. 1990s Late in the decade, Virtual Private Networks ( VPNs ) based on the Layer 2 Tunneling Protocol (L2TP) and IPSEC ...L2TP – Layer Two Tunnel Protocol LBNL – Lawrence Berkeley National Lab MHZ – Megahertz MIO – Maritime Interdiction Operations NOC – Network...Vehicle UHF – Ultra-High Frequency VPN – Virtual Private Network xvii ACKNOWLEDGMENTS First and foremost, we would like to thank our spouses Fatima

  15. Functionalization of polymer surfaces by medium frequency non-thermal plasma

    Science.gov (United States)

    Felix, T.; Trigueiro, J. S.; Bundaleski, N.; Teodoro, O. M. N. D.; Sério, S.; Debacher, N. A.

    2018-01-01

    This work addresses the surface modification of different polymers by argon dielectric barrier discharge, using bromoform vapours. Atomic Force Microscopy and Scanning Electron Microscopy showed that plasma etching occurs in stages and may be related to the reach of the species generated and obviously the gap between the electrodes. In addition, the stages of flatten surface or homogeneity may be the result of the transient crosslinking promoted by the intense UV radiation generated by the non- thermal plasma. X-ray Photoelectron Spectroscopy analysis showed that bromine was inserted on the polymer surface as Csbnd Br bonds and as adsorbed HBr. The obtained results demonstrate that the highest degree of bromofunctionalization was achieved on polypropylene surface, which contains about 8,5% of Br. After its derivatization in ammonia, Br disappeared and about 6% of nitrogen in the form of amine group was incorporated at the surface. This result can be considered as a clear fingerprint of the Br substitution by the amine group, thus illustrating the efficiency of the proposed method for functionalization of polymer surfaces.

  16. Medium, Long and Very Long Wave Propagation (at Frequencies Less than 3000 kHz)

    Science.gov (United States)

    1982-02-01

    for the scat ier, ng body is the Geo- Corona . i.e. The local hydrogen gas cloud around the earth. PAPER: 3. )LF/LF PULSE REFIELTIC4I MEASL’REMENTS UF...P, Hamaide, W. Scholiers, 1-P. Lechien Universati Libre de Bruxelles Campus Plamne, C.P. 222, Boulevard do Triomphe, 1030 Bruxelles (Belgium) SUMMARY... metal wire several hundred kilo- meters long, kept aligned along the vertical by gravity gradient forces, have shown that there is a large source of

  17. Assessment of Lubricity Properties of Dimethyl Ether Using the Medium Frequency Reciprocating Rig

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Sorenson, Spencer C

    2001-01-01

    Adequate lubricity of a fuel is an important issue when the wear in diesel engine injection equipment is to be minimised. For conventional diesel oils, there exist methods capable of measuring the lubricity of the fuels. These methods cannot handle Dimethyl Ether (DME), as it has to be pressurised...... exceptionally low. By mixing the DME with very small quantities of additives the lubricity can be redressed. Only one additive was capable of giving DME a lubricity higher than the one of diesel oil. Even at such high lubricities it cannot be concluded that wear in the diesel injection pumps....... The calibration was achieved by using both the standard method for diesel oil and the MFPRR, to test three liquid fuels of varying lubricities. The result was that the MFPRR discriminated just as well between the fuel lubricities as did the standard method. The lubricity of DME was measured and was found...

  18. Nitrogen Chemistry in the Interstellar Medium

    Science.gov (United States)

    McGonagle, D.

    1995-01-01

    We have carried out radio observations for the interstellar molecules NO, NS, and HCCN in order to investigate the role of nitrogen in the chemistry of the interstellar medium (ISM). Abundances of these species and implications for chemistry models are discussed. In addition, we have conducted a spectral line survey towards the star forming region Orion(KL) over the frequency range 160-170 GHz, which revealed a large number of spectral features arising from such nitrogen-bearing molecules as NS, HNCO, HCCCN, CHCN, CHCHCN, and CHCHCN. The first detection of interstellar nitric oxide (NO) in the cold dark cloud L134N is reported, and we also confirm the subsequent detection towards TMC-1. The inferred NO fractional abundance relative to molecular hydrogen for L134N is f ~ 5 W 10 towards the position of peak SO emission in that cloud. The inferred fractional abundance for TMC-1 is f ~ 2 W 10 towards the position of peak NH emission. These fractional abundances are in good agreement with predictions of quiescent cloud ion-molecule chemistry. We estimate f(N)/f(NO) ~ 140, which suggests that the bulk of the gas-phase nitrogen in quiescent clouds is in the form of N , as the ion-molecule chemistry models suggest. The first detection of interstellar nitrogen sulfide (NS) in cold dark clouds is reported. Several components of the , J = 3/2 --> 1/2 and J = 5/2 --> 3/2 rotational transitions were observed towards TMC-1 and L134N. The inferred column density for TMC-1 is f ~ 8 W 10 towards the NH peak in that cloud, and in L134N is f ~ 6 W 10 towards the position of peak NH emission. We have found that NS emission is extended in both clouds. The inferred NS fractional abundances are significantly higher than those predicted by some recent gas-phase ion-molecule models. Our astronomical observations of NS have led to new laboratory spectroscopy which has resulted in more accurate NS transition frequencies, and a corresponding determination of the NS molecular constants to a

  19. Fast fundamental frequency estimation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

    2017-01-01

    Modelling signals as being periodic is common in many applications. Such periodic signals can be represented by a weighted sum of sinusoids with frequencies being an integer multiple of the fundamental frequency. Due to its widespread use, numerous methods have been proposed to estimate the funda...

  20. Electrothermal frequency reference

    NARCIS (Netherlands)

    Makinwa, K.A.A.; Kashmiri, S.M.

    2011-01-01

    An electrothermal frequency-locked loop (EFLL) circuit is described. This EFLL circuit includes an oscillator in a feedback loop. A drive circuit in the EFLL circuit generates a first signal having a fundamental frequency, and an electrothermal filter (ETF) in the EFLL circuit provides a second

  1. Single frequency intracavity SRO

    DEFF Research Database (Denmark)

    Abitan, Haim; Buchhave, Preben

    2000-01-01

    Summary form only given. A single resonance optical parametric oscillator (SRO) is inserted intracavity to a CW high power, single frequency, and ring Nd:YVO4 laser. We obtain a stable single frequency CW SRO with output at 1.7-1.9 μm (idler) and a resonating signal at 2.3-2.6 μm. The behavior...

  2. Acoustic performance of gratings of cylindrical voids in a soft elastic medium with a steel backing.

    Science.gov (United States)

    Sharma, Gyani Shankar; Skvortsov, Alex; MacGillivray, Ian; Kessissoglou, Nicole

    2017-06-01

    An approximate analytical model is presented to investigate sound transmission, reflection and absorption of a rubber-like medium comprising a single layer of periodic cylindrical voids attached to a steel backing. The layer of voids is modelled as a homogeneous medium with effective material and geometric properties. A numerical model based on the finite element method is developed to validate results from the homogenization model, as well as to show further insights into the physical mechanisms associated with the system acoustic performance. Monopole resonance of the voids is shown to reduce sound transmission through the voided medium due to increased reflection, resulting in poor sound absorption around this frequency. Peaks of high sound absorption are attributed to Fabry-Pérot resonance with the frequency of the first peak derivable by a lumped spring-mass analogy. Sound absorption for a single layer of voids in a soft elastic medium with a steel backing is shown to be similar to the sound absorption in the same elastic medium but without the steel backing, for a single layer of voids and its mirror image in the direction of sound propagation.

  3. Microfabricated ion frequency standard

    Science.gov (United States)

    Schwindt, Peter; Biedermann, Grant; Blain, Matthew G.; Stick, Daniel L.; Serkland, Darwin K.; Olsson, III, Roy H.

    2010-12-28

    A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

  4. Aperiodic space-time modulation for pure frequency mixing

    Science.gov (United States)

    Taravati, Sajjad

    2018-03-01

    This paper experimentally demonstrates the effects of inharmonic photonic transition in tailored aperiodic space-time refractive index modulated media. Such effects introduce a pure frequency mixing based on the simultaneous and distinct shifts in the spatial and temporal frequencies. The medium is characterized with a periodic temporal modulation and a tailored aperiodic spatially modulated permittivity and permeability, yielding aperiodic, large and tunable photonic band gaps. Since the medium is time periodic, an infinite number of space-time mixing products are generated with a distance equal to the temporal frequency of the pump wave. However, thanks to the tailored spatial aperiodicity of the medium and associated photonic band gaps, transition to unwanted space-time mixing products is prohibited. Interesting features include tunability of the operation frequencies of the mixer via space-time modulation parameters, high isolation, linear response, and possibility of conversion gain due to the transfer of energy and momentum of the space-time modulation to the input wave. We derive the analytical solution for such mixer with aperiodic space-modulated permittivity and permeability and periodic time modulation, and then provide the synthesis procedure which takes into account the effects of space-time modulation inhomogeneity. Finally, to see the effect of the tailoring of space modulation, we compare the experimental results of the aperiodic space-time modulated pure mixer with those of the conventional periodic uniform space-time modulated medium.

  5. Surface modification of lignocellulosic fibers using high-frequency ultrasound

    Science.gov (United States)

    Jayant B. Gadhe; Ram B. Gupta; Thomas Elder

    2005-01-01

    Enzymatic and chemical oxidation of fiber surfaces has been reported in the literature as a method for producing medium density fiberboards without using synthetic adhesives. This work focuses on modifying the surface properties of wood fibers by the generation of free radicals using high-frequency ultrasound. A sonochemical reactor operating at 610 kHz is used to...

  6. Collision frequency shift of a short electromagnetic pulse

    International Nuclear Information System (INIS)

    Chegotov, M V

    2004-01-01

    The frequency shift of a short electromagnetic pulse interaction with a plasma-like medium is discovered and studied. The shift is caused by elastic collisions of free electrons with ions or neutral particles. (interaction of laser radiation with matter. laser plasma)

  7. Meson's correlation functions in a nuclear medium

    Directory of Open Access Journals (Sweden)

    Chanyong Park

    2016-09-01

    Full Text Available We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the ρ-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.

  8. Ioversol contrast medium in canine neuroradiology

    International Nuclear Information System (INIS)

    Tudury, E.A.; Arias, M.V.B.; Camargo, P.L. de; Faria, M. de L.E.; Machado, C.E.G.

    1997-01-01

    Ioversol, a non-ionic, hydrosoluble iodine contrast medium at a concentration of 320mg I/ml was used to perform 26 contrast neuroradiographic studies (myelography, epidurography and cerebral ventriculography) in 22 dogs. Since this contrast medium is rapidly absorbed, proper radiographs were obtained within 30 minutes of injection. The product showed adequate radio-opacity, retention time, diffusion and liquor miscibility. Minimal side effects both during and after the radiographic procedures were observed. Not one patient developed seizures, in spite of the use of anesthetic protocols that included either zolarepan-tiletamine or levomepromazin- zilazine- or diazepam-sodium thiopental. The presentation of the contrast medium in a multiple dose vial was considered an advantage, since it decreases losses and allows repeated sterilization in autoclave [pt

  9. Coherent neutrino interactions in a dense medium

    International Nuclear Information System (INIS)

    Kiers, K.; Weiss, N.

    1997-01-01

    Motivated by the effect of matter on neutrino oscillations (the MSW effect) we study in more detail the propagation of neutrinos in a dense medium. The dispersion relation for massive neutrinos in a medium is known to have a minimum at nonzero momentum p∼G F ρ/√(2). We study in detail the origin and consequences of this dispersion relation for both Dirac and Majorana neutrinos both in a toy model with only neutral currents and a single neutrino flavor and in a realistic open-quotes standard modelclose quotes with two neutrino flavors. We find that for a range of neutrino momenta near the minimum of the dispersion relation, Dirac neutrinos are trapped by their coherent interactions with the medium. This effect does not lead to the trapping of Majorana neutrinos. copyright 1997 The American Physical Society

  10. Positron annihilation in the interstellar medium

    Science.gov (United States)

    Guessoum, Nidhal; Ramaty, Reuven; Lingenfelter, Richard E.

    1991-01-01

    Positronium formation and annihilation are studied in a model for the interstellar medium consisting of cold cloud cores, warm partially ionized cloud envelopes, and hot intercloud gas. The gamma-ray spectra resulting from positron annihilation in these components of the interstellar medium are calculated. The spectra from the individual components are then combined, using two limiting assumptions for the propagation of the positrons, namely, that the positrons propagate freely throughout the interstellar medium, and that the positrons are excluded from the cold cloud cores. In the first case, the bulk of the positrons annihilate in the cloud cores and the annihilation line exhibits broad wings resulting from the annihilation of positronium formed by charge exchange in flight. In the second case, the positrons annihilate mainly in the warm envelopes, and the line wings are suppressed.

  11. Charmonium propagation through a dense medium

    Directory of Open Access Journals (Sweden)

    Kopeliovich B.Z.

    2015-01-01

    Full Text Available Attenuation of a colourless c̄c dipole propagating with a large momentum through a hot medium originates from two sources, Debye screening (melting, and inelastic collisions with surrounding scattering centres (absorption. The former never terminates completely production of a bound charmonium in heavy ion collisions, even at very high temperatures. The latter, is controlled my the magnitude of the dipole cross section, related to the transport coefficient, which is the rate of transverse momentum broadening in the medium. A novel procedure of Lorentz boosting of the Schrödinger equation is developed, which allows to calculate the charmonium survival probability employing the path-integral technique, incorporating both melting and absorption. A novel mechanism of charmonium regeneration in a dense medium is proposed.

  12. Cutaneous Manifestations of Medium- and Large-Vessel Vasculitis.

    Science.gov (United States)

    Chasset, Francois; Francès, Camille

    2017-12-01

    Dermatologic manifestations are observed in almost all systemic vasculitides, even in large-and medium-vessel vasculitides, although such vessels are not found in the skin. Cutaneous manifestations may be related to a direct skin localization of the systemic vasculitis or a non-specific process associated with the vasculitis. According to the 2012 International Chapel Hill consensus, the two major variants of large-vessel vasculitides are Takayasu arteritis and giant-cell arteritis. In Europe and North America, acute inflammatory nodules or erythema nodosum-like lesions are the most commonly observed skin lesions with Takayasu arteritis. Medium-sized arteriole vasculitis of the dermis or subcutis but also septal or lobular panniculitis may be found during pathological examination. In Japan, widespread pyoderma gangrenosum-like lesions are more frequent. Cutaneous manifestations of giant-cell arteritis are rare; they are ischemic, linked to arterial occlusions, or non-ischemic, with various mechanisms. The two major medium-vessel vasculitides are Kawasaki disease and polyarteritis nodosa. Kawasaki disease is characterized by a mucocutaneous lymph node syndrome without skin vasculitis. Two subsets of polyarteritis nodosa with different skin manifestations are described, without transition from one to the other. In the systemic subset, the most frequent skin lesions are in the order of frequency purpura, livedo, and nodules. Cutaneous polyarteritis nodosa mainly features nodules, livedo racemosa, and ulcerations. Genetic screening and measurement of plasma levels of adenosine deaminase 2 should be considered for patients with uncommon systemic polyarteritis nodosa or early-onset cutaneous polyarteritis nodosa.

  13. [A modified MacConkey medium].

    Science.gov (United States)

    Wang, J; Tong, M

    1999-01-01

    We used MacConkey Agar(MCA) medium powder as a basis and added 6-benzoy-2-naphthyl phosphate disodium salt to modify MCA medium. This method was identified by examining several kinds of enteric pathogenic bacteria. Thus it allows us to observe lactose fermentative and phosphatase reaction simultaneously and to recognize Enterobacteriaceae from non-fermentable bacteria on primary culture plates according to the color of colony. This improved method simplifies the recognition procedure and shortens the time so that it is helpful to correctly choosing identification kit.

  14. Power converters for medium voltage networks

    CERN Document Server

    Islam, Md Rabiul; Zhu, Jianguo

    2014-01-01

    This book examines a number of topics, mainly in connection with advances in semiconductor devices and magnetic materials and developments in medium and large-scale renewable power plant technologies, grid integration techniques and new converter topologies, including advanced digital control systems for medium-voltage networks. The book's individual chapters provide an extensive compilation of fundamental theories and in-depth information on current research and development trends, while also exploring new approaches to overcoming some critical limitations of conventional grid integration te

  15. Breakfast frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Damsgaard, Mogens Trab

    2016-01-01

    OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary by sociodemo......OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary...... by sociodemographic factors. DESIGN: School-based cross-sectional study. Students completed a web-based questionnaire. Associations were estimated by multilevel multivariate logistic regression. SETTING: Danish arm of the Health Behaviour in School-aged Children study, 2014. SUBJECTS: Adolescents aged 13 and 15 years...... (n 3054) from a random sample of forty-one schools. RESULTS: Nearly one-quarter of the adolescents had low breakfast frequency. Low breakfast frequency was associated with low family functioning measured by three dimensions. The OR (95 % CI) of low breakfast frequency was 1·81 (1·40, 2...

  16. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  17. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  18. Neutrino propagation in a weakly magnetized medium

    Indian Academy of Sciences (India)

    The organization of the paper is as follows: In §2 we discuss the basics of neutrino–photon effective action and the fermion propagators in a magnetized medium. Section 3 contains the details of the calculation of the one-loop diagram and in §4 we consider the weak-field limit. Finally, we conclude with a discussion.

  19. Gravitational Instability of Cylindrical Viscoelastic Medium ...

    Indian Academy of Sciences (India)

    symmetric cylinder of viscoelastic medium permeated with non uniform ... plasma (SCP) and weakly coupled plasma (WCP). The non uniform mag- netic field and rotation are considered to act along the axial direction of the cylinder. ... disperse, cold gas to collapse was given by Sir James Jeans (1902) and now known.

  20. Reflection of light from an anisotropic medium

    OpenAIRE

    Ignatovich, Filipp V.; Ignatovich, Vladimir

    2010-01-01

    We present here a general approach to treat reflection and refraction of light of arbitrary polarization from single axis anisotropic plates. We show that reflection from interface inside the anisotropic medium is accompanied by beam splitting and can create surface waves.

  1. Medium-range fire weather forecasts

    Science.gov (United States)

    J.O. Roads; K. Ueyoshi; S.C. Chen; J. Alpert; F. Fujioka

    1991-01-01

    The forecast skill of theNational Meteorological Center's medium range forecast (MRF) numerical forecasts of fire weather variables is assessed for the period June 1,1988 to May 31,1990. Near-surface virtual temperature, relative humidity, wind speed and a derived fire weather index (FWI) are forecast well by the MRF model. However, forecast relative humidity has...

  2. Influence of small and medium building engineering ...

    African Journals Online (AJOL)

    This study investigated the influence of small and medium building engineering entrepreneurship for the actualization of vision 20:2020 in Kebbi State, Nigeria. The study was conducted in Birnin Kebbi, Zuru and Argungu Local Government Areas of Kebbi State. The data were obtained from both primary and secondary ...

  3. Medium density fiberboard from mixed southern hardwoods

    Science.gov (United States)

    George E. Woodson

    1977-01-01

    Medium-density fiberboards of acceptable quality were made from a mixture of barky chips from 14 southern hardwoods. Boards made from fiber refined at three different plate clearances did not vary significantly in bending, internal bond (IB), or linear expansion. but, lack of replications and the fact that the refiner was not loaded to capacity caused these results to...

  4. Medium for Children’s Creativity

    DEFF Research Database (Denmark)

    Borum, Nanna; Kristensen, Kasper; Petersson, Eva

    2014-01-01

    This paper reports on an exploratory study that investigates 16 elementary school children’s interaction with two different mediums for creativity, LEGO® bricks and paper collages, drawing on the previous creativity assessment test carried out by Amabile [1]. The study is based in a playful...

  5. Theatrical Complicity as a Medium of Emancipation

    DEFF Research Database (Denmark)

    Nielsen, Thomas Rosendal

    2015-01-01

    of theatricality are re-described in a systems theoretical perspective in order to show how the theatrical attribution of guilt to the spectator can work as a medium of emancipation. The explication of the different dramaturgies makes it possible to distinguish between how self-righteous, self...

  6. Intergalactic medium heating by dark matter

    NARCIS (Netherlands)

    Ripamonti, E.; Mapelli, M.; Ferrara, A.

    2006-01-01

    Abstract: We derive the evolution of the energy deposition in the intergalactic medium (IGM) by dark matter (DM) decays/annihilations for both sterile neutrinos and light dark matter (LDM) particles. At z > 200 sterile neutrinos transfer a fraction f_abs~0.5 of their rest mass energy into the IGM;

  7. Borromean structures in medium-heavy nuclei

    DEFF Research Database (Denmark)

    Hove, Dennis; Fedorov, Dmitri Vladimir; Fynbo, Hans Otto Uldall

    2014-01-01

    Borromean nuclear cluster structures are expected at the corresponding driplines. We locate the regions in the nuclear chart with the most promising constituents, it being protons and alpha-particles and investigate in details the properties of the possible borromean two-alpha systems in medium h...

  8. The MIRI Medium Resolution Spectrometer calibration pipeline

    NARCIS (Netherlands)

    Labiano, A.; Azzollini, R.; Bailey, J.; Beard, S.; Dicken, D.; García-Marín, M.; Geers, V.; Glasse, A.; Glauser, A.; Gordon, K.; Justtanont, K.; Klaassen, P.; Lahuis, F.; Law, D.; Morrison, J.; Müller, M.; Rieke, G.; Vandenbussche, B.; Wright, G.

    2016-01-01

    The Mid-Infrared Instrument (MIRI) Medium Resolution Spectrometer (MRS) is the only mid-IR Integral Field Spectrometer on board James Webb Space Telescope. The complexity of the MRS requires a very specialized pipeline, with some specific steps not present in other pipelines of JWST instruments,

  9. Innovation in Small and Medium Firms.

    Science.gov (United States)

    Organisation for Economic Cooperation and Development, Paris (France). Committee for Scientific and Technical Personnel.

    A study analyzed the policies of 20 Organisation for Economic Cooperation and Development (OECD) member countries pertaining to small and medium enterprises (SMEs). Aims of the study were to assess the current role of SMEs as generators and users of innovations, to analyze the components of a favorable climate for innovation in SMEs, and to…

  10. Absorption line spectroscopy of the interstellar medium

    International Nuclear Information System (INIS)

    Jura, M.

    1983-01-01

    Absorption line studies of the interstellar medium are described. The discussion is in three parts. The first describes current views of diffuse interstellar clouds, while the second reports the results of recent extensive surveys of interstellar regions. The final part is an outline of possible future observations. (orig.)

  11. Nuclear matter as a nonlinear optical medium

    International Nuclear Information System (INIS)

    Hefter, E.F.; Papini, G.

    1986-01-01

    This paper is concerned with the question whether nuclear matter should be considered as a nonlinear optical medium. Taking, in a pragmatic way, quality and quantity of the results of well-established linear and nonlinear approaches as the main criterion, an affirmative answer is seen to be consistent with long-standing practices adhered to in nuclear physics

  12. Radiculography with water-soluble contraste medium

    International Nuclear Information System (INIS)

    Araujo Pinheiro, R.S. de

    1987-01-01

    The etiologic diagnosis of the lumbar pain is discussed. The radiculography with water-soluble contrast medium is used and 250 cases are studied. Some practical criteria of indication executation and interpretation of the examination are reported. (M.A.C.) [pt

  13. Medium optimization for endochitinase production by recombinant ...

    African Journals Online (AJOL)

    The optimal concentrations of three factors were investigated by the response surface methodology using Box- Behnken design. The optimal medium components obtained for achieving the maximum activity of the endochitinase were as follows: Yeast extract 24.36 g/l, tryptone 20 g/l, YNB 5.0 g/l, potassium phosphate 100 ...

  14. Intergalactic medium heating by dark matter

    NARCIS (Netherlands)

    Ripamonti, E.; Mapelli, M.; Ferrara, A.

    2007-01-01

    We derive the evolution of the energy deposition in the intergalactic medium (IGM) by dark matter (DM) decays/annihilations for both sterile neutrinos and light dark matter (LDM) particles. At z > 200 sterile neutrinos transfer a fraction f(abs) similar to 0.5 of their rest mass energy into the IGM;

  15. The Digital Medium Meets the Advertising Message.

    Science.gov (United States)

    Nisenholtz, Martin

    1994-01-01

    Discusses the likelihood that companies will use online services as an advertising medium. Topics addressed include the art of interactive marketing; advertising in the digital age; early experiments with interactive marketing, including the use of videotex and videodisc; and recent trends that set the stage for interactive marketing to personal…

  16. Nonlinear real index of refraction variations of a gas medium due to a monochromatic radiation near resonance

    International Nuclear Information System (INIS)

    Vasconcellos, J.I.C.

    1982-01-01

    The nonlinear real index of refraction variations of a gas medium due to a strong monochromatic radiation causing saturation effects is calculated. The gas is supposed to be composed of two-level molecules with which the external field is nearly resonant. It is assumed homogeneous (hard collisions, spontaneous decay) and inhomogeneous (Doppler effect) broadening mechanisms acting on the real index of refraction of the medium. The nonlinear dispersion of the medium is studied as a function of the detuning frequencies, saturation conditions and for various ratios between the homogeneous and inhomogeneous linewidths. In particular, the modification of the index of refraction due to saturation effects are emphasized. (Author) [pt

  17. Asynchronous BCI control using high-frequency SSVEP

    Directory of Open Access Journals (Sweden)

    Laciar Leber Eric

    2011-07-01

    Full Text Available Abstract Background Steady-State Visual Evoked Potential (SSVEP is a visual cortical response evoked by repetitive stimuli with a light source flickering at frequencies above 4 Hz and could be classified into three ranges: low (up to 12 Hz, medium (12-30 and high frequency (> 30 Hz. SSVEP-based Brain-Computer Interfaces (BCI are principally focused on the low and medium range of frequencies whereas there are only a few projects in the high-frequency range. However, they only evaluate the performance of different methods to extract SSVEP. Methods This research proposed a high-frequency SSVEP-based asynchronous BCI in order to control the navigation of a mobile object on the screen through a scenario and to reach its final destination. This could help impaired people to navigate a robotic wheelchair. There were three different scenarios with different difficulty levels (easy, medium and difficult. The signal processing method is based on Fourier transform and three EEG measurement channels. Results The research obtained accuracies ranging in classification from 65% to 100% with Information Transfer Rate varying from 9.4 to 45 bits/min. Conclusions Our proposed method allows all subjects participating in the study to control the mobile object and to reach a final target without prior training.

  18. Frequency mixing in boron carbide laser ablation plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Oujja, M.; Benítez-Cañete, A.; Sanz, M.; Lopez-Quintas, I.; Martín, M.; Nalda, R. de, E-mail: r.nalda@iqfr.csic.es; Castillejo, M.

    2015-05-01

    Graphical abstract: - Highlights: • Two-color frequency mixing has been studied in a laser ablation boron carbide plasma. • A space- and time-resolved study mapped the nonlinear optical species in the plasma. • The nonlinear process maximizes when charge recombination is expected to be completed. • Neutral atoms and small molecules are the main nonlinear species in this medium. • Evidence points to six-wave mixing as the most likely process. - Abstract: Nonlinear frequency mixing induced by a bichromatic field (1064 nm + 532 nm obtained from a Q-switched Nd:YAG laser) in a boron carbide (B{sub 4}C) plasma generated through laser ablation under vacuum is explored. A UV beam at the frequency of the fourth harmonic of the fundamental frequency (266 nm) was generated. The dependence of the efficiency of the process as function of the intensities of the driving lasers differs from the expected behavior for four-wave mixing, and point toward a six-wave mixing process. The frequency mixing process was strongly favored for parallel polarizations of the two driving beams. Through spatiotemporal mapping, the conditions for maximum efficiency were found for a significant delay from the ablation event (200 ns), when the medium is expected to be a low-ionized plasma. No late components of the harmonic signal were detected, indicating a largely atomized medium.

  19. High-frequency strontium vapor laser for biomedical applications

    Science.gov (United States)

    Hvorostovsky, A.; Kolmakov, E.; Kudashev, I.; Redka, D.; Kancer, A.; Kustikova, M.; Bykovskaya, E.; Mayurova, A.; Stupnikov, A.; Ruzankina, J.; Tsvetkov, K.; Lukyanov, N.; Paklinov, N.

    2018-02-01

    Sr-laser with high pulse repetition rate and high peak radiation power is a unique tool for studying rapidly occurring processes in time (plasma diagnostics, photoablation, etc.). In addition, the study of the frequency characteristics of the active medium of the laser helps to reveal the physics of the formation of an inverse medium in metal vapor lasers. In this paper, an experimental study of an Sr-laser with an active volume of 5.8 cm3 in the pulse repetition frequency range from 25 to 200 kHz is carried out, and a comparison with the frequency characteristics of media with large active volumes is given. We considered the frequency characteristics of the active medium in two modes: at a constant energy in the excitation pulse CU2 / 2 and at a constant average power consumed by the rectifier. In the presented work with a small-volume GRT using the TASITR-5/12 TASITRON switch, a laser was generated for Pairs of strontium at a CSF of 200 kHz. The behavior of the characteristics of the generation lines of 6.456 μm, 1 μm, and 3 μm at increased repetition frequencies is considered. Using the example of large-volume GRT, it is shown that tubes with a large active volume increase their energy characteristics with the growth of the CSF. The possibility of laser operation at pulse repetition rates above 200 kHz is shown.

  20. Medium energy heavy ion operations at RHIC

    International Nuclear Information System (INIS)

    Drees, K.A.; Ahrens, L.; Bai, M.; Beebe-Wang, J.; Blackler, I.M.C.; Blaskiewicz, M.; Brown, K.A.; Brennan, M.; Bruno, D.; Butler, J.; Carlson, C.; Connolly, R.; D'Ottavio, T.; Fischer, W.; Fu, W.; Gassner, D.; Harvey, M.; Hayes, T.; Huang, H.; Hulsart, R.; Ingrassia, P.; Kling, N.; Lafky, M.; Laster, J.; Lee, R.C.; Litvinenko, V.; Luo, Y.; MacKay, W.W.; Marr, G.; Mapes, M.; Marusic, A.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Morris, J.; Naylor, C.; Nemesure, S.; Pilat, F.; Ptitsyn, V.; Robert-Demolaize, G.; Roser, T.; Sampson, P.; Satogata, T.; Schoefer, V.; Schultheiss, C.; Severino, F.; Shrey, T.; Smith, K.S.; Tepikian, S.; Thieberger, P.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.; van Kuik, B.; Wilinski, M.; Zaltsman, A.; Zeno, K.; Zhang, S.Y.

    2011-01-01

    As part of the search for a phase transition or critical point on the QCD phase diagram, an energy scan including 5 different energy settings was performed during the 2010 RHIC heavy ion run. While the top beam energy for heavy ions is at 100 GeV/n and the lowest achieved energy setpoint was significantly below RHICs injection energy of approximately 10 GeV/n, we also provided beams for data taking in a medium energy range above injection energy and below top beam energy. This paper reviews RHIC experience and challenges for RHIC medium energy operations that produced full experimental data sets at beam energies of 31.2 GeV/n and 19.5 GeV/n. The medium energy AuAu run covered two beam energies, both above the RHIC injection energy of 9.8 GeV but well below the standard store energy of 100 GeV (see table 1). The low energy and full energy runs with heavy ions in FY10 are summarized in (1) and (2). Stochastic Cooling ((3)) was only used for 100 GeV beams and not used in the medium energy run. The efficiency of the transition from 100 GeV operation to 31.2 GeV and then to 19.5 GeV was remarkable. Setup took 32 h and 19 h respectively for the two energy settings. The time in store, defined to be the percentage of time RHIC provides beams in physics conditions versus calendar time, was approximately 52% for the entire FY10 heavy ion run. In both medium energy runs it was well above this average, 68% for 31.5 GeV and 82% for 19.5 GeV. For both energies RHIC was filled with 111 bunches with 1.2 10 9 and 1.3 10 9 ions per bunch respectively.

  1. Medium energy heavy ion operations at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Drees, K.A.; Ahrens, L.; Bai, M.; Beebe-Wang, J.; Blackler, I.M.C.; Blaskiewicz, M.; Brown, K.A.; Brennan, M.; Bruno, D.; Butler, J.; Carlson, C.; Connolly, R.; D' Ottavio, T.; Fischer, W.; Fu, W.; Gassner, D.; Harvey, M.; Hayes, T.; Huang, H.; Hulsart, R.; Ingrassia, P.; Kling, N.; Lafky, M.; Laster, J.; Lee, R.C.; Litvinenko, V.; Luo, Y.; MacKay, W.W.; Marr, G.; Mapes. M.; Marusic, A.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Morris, J.; Naylor, C.; Nemesure, S.; Pilat, F.; Ptitsyn, V.; Robert-Demolaize, G.; Roser, T.; Sampson, P.; Satogata, T.; Schoefer, V.; Schultheiss, C.; Severino, F.; Shrey, T.; Smith, K.S.; Tepikian, S.; Thieberger, P.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.; van Kuik, B.; Wilinski, M.; Zaltsman, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    As part of the search for a phase transition or critical point on the QCD phase diagram, an energy scan including 5 different energy settings was performed during the 2010 RHIC heavy ion run. While the top beam energy for heavy ions is at 100 GeV/n and the lowest achieved energy setpoint was significantly below RHICs injection energy of approximately 10 GeV/n, we also provided beams for data taking in a medium energy range above injection energy and below top beam energy. This paper reviews RHIC experience and challenges for RHIC medium energy operations that produced full experimental data sets at beam energies of 31.2 GeV/n and 19.5 GeV/n. The medium energy AuAu run covered two beam energies, both above the RHIC injection energy of 9.8 GeV but well below the standard store energy of 100 GeV (see table 1). The low energy and full energy runs with heavy ions in FY10 are summarized in [1] and [2]. Stochastic Cooling ([3]) was only used for 100 GeV beams and not used in the medium energy run. The efficiency of the transition from 100 GeV operation to 31.2 GeV and then to 19.5 GeV was remarkable. Setup took 32 h and 19 h respectively for the two energy settings. The time in store, defined to be the percentage of time RHIC provides beams in physics conditions versus calendar time, was approximately 52% for the entire FY10 heavy ion run. In both medium energy runs it was well above this average, 68% for 31.5 GeV and 82% for 19.5 GeV. For both energies RHIC was filled with 111 bunches with 1.2 10{sup 9} and 1.3 10{sup 9} ions per bunch respectively.

  2. Shape instability of a bubble in a viscoelastic medium

    Science.gov (United States)

    Murakami, Kazuya; Gaudron, Renaud; Johnsen, Eric

    2017-11-01

    Bubble dynamics play an important role in therapeutic ultrasound and other medical applications. For this reason, we investigate the shape instability of a single gas bubble in a viscoelastic, tissue-mimicking medium. The non-spherical bubble surface is expressed by superposition of spherical harmonics. Cauchy's equation of motion is reduced to two ordinary differential equations: the Rayleigh-Plesset type equation for the mean bubble radius and the equation for the mode amplitude, which are solved simultaneously. For a given bubble radius and frequency, the parametric instability is determined by the n-th order natural frequency. In addition, the amplitude threshold of the mean radius is analytically found by the stability theory for Mathieu equation. Our analysis is validated against experimental results, in which non-spherical bubble oscillations are observed under ultrasound irradiation. Finally, the pressure threshold for the shape instability is numerically examined. This work was supported in part by ONR Grant N00014-17-1-2058 (under Dr. T. Bentley) and NSF Grant CBET 1253157.

  3. The structure of plasma density irregularities in the interplanetary medium

    International Nuclear Information System (INIS)

    Singleton, D.G.

    1975-01-01

    Observations of the scintillation of sources 3C273 and 3C279 at 2292 MHz are described. The interpretation of the scintillation in terms of the structure of the plasma-density irregularities in the interplanetary medium is discussed. Scintillation index measurements obtained during these observations are combined with similar measurements at other frequencies reported in the literature. The resulting variation of the scintillation-index and observing-frequency product with source elongation is interpreted in terms of irregularities with a spatial spectrum of electron density which is of power law form. This result is reinforced by an analysis of the spectra of the observed scintillations. Several tests are applied to both the Fourier and Bessel spectra which illustrate conclusively that the irregularity spatial spectrum is of power law form, rather than the Gaussian form suggested by some workers. The spectra also show that the irregularities are isotopic within 0.2 AU of the sun, while there is some evidence that a degree of elongation normal to the direction of the motion of the irregularities may develop at slightly greater solar distances. The irregularity velocities determined are consistent with solar wind velocities. (author)

  4. Robust Unit Commitment Including Frequency Stability Constraints

    Directory of Open Access Journals (Sweden)

    Felipe Pérez-Illanes

    2016-11-01

    Full Text Available An increased use of variable generation technologies such as wind power and photovoltaic generation can have important effects on system frequency performance during normal operation as well as contingencies. The main reasons are the operational principles and inherent characteristics of these power plants like operation at maximum power point and no inertial response during power system imbalances. This has led to new challenges for Transmission System Operators in terms of ensuring system security during contingencies. In this context, this paper proposes a Robust Unit Commitment including a set of additional frequency stability constraints. To do this, a simplified dynamic model of the initial system frequency response is used in combination with historical frequency nadir data during contingencies. The proposed approach is especially suitable for power systems with cost-based economic dispatch like those in most Latin American countries. The study is done considering the Northern Interconnected System of Chile, a 50-Hz medium size isolated power system. The results obtained were validated by means of dynamic simulations of different system contingencies.

  5. Quenching of natural cyclotron instability by large amplitude monochromatic waves propagating in an inhomogeneous medium

    International Nuclear Information System (INIS)

    Cornilleau-Wehrlin, N.; Gendrin, R.

    1979-01-01

    Recent experiments have shown that a long duration monochromatic wave generated by a high power VLF transmitter may quench natural magnetospheric hiss emissions over a frequency range Δf of the order of 50-150 Hz below the transmitter frequency. The authors show that this effect can be interpreted by trapping, inside the monochromatic wave, of a certain amount of particles which were contributing to the generation of hiss in the equatorial region before the transmitter was switched on. The competition between the trapping and detrapping forces (the last one being due to the inhomogeneity of the medium) is studied. They show that the frequency range Δf which is concerned by this effect is proportional to b 2 , where b is the field intensity of the monochromatic wave. Δf is also an increasing function of the transmitter frequency. (Auth.)

  6. Time-domain Helmholtz-Kirchhoff integral for surface scattering in a refractive medium.

    Science.gov (United States)

    Choo, Youngmin; Song, H C; Seong, Woojae

    2017-03-01

    The time-domain Helmholtz-Kirchhoff (H-K) integral for surface scattering is derived for a refractive medium, which can handle shadowing effects. The starting point is the H-K integral in the frequency domain. In the high-frequency limit, the Green's function can be calculated by ray theory, while the normal derivative of the incident pressure from a point source is formulated using the ray geometry and ray-based Green's function. For a corrugated pressure-release surface, a stationary phase approximation can be applied to the H-K integral, reducing the surface integral to a line integral. Finally, a computationally-efficient, time-domain H-K integral is derived using an inverse Fourier transform. A broadband signal scattered from a sinusoidal surface in an upwardly refracting medium is evaluated with and without geometric shadow corrections, and compared to the result from a conventional ray model.

  7. Noise Budget and Interstellar Medium Mitigation Advances in the NANOGrav Pulsar Timing Array

    Science.gov (United States)

    Dolch, T.; NANOGrav Collaboration; Chatterjee, S.; Cordes, J. M.; Demorest, P. B.; Ellis, J. A.; Jones, M. L.; Lam, M. T.; Lazio, T. J. W.; Levin, L.; McLaughlin, M. A.; Palliyaguru, N. T.; Stinebring, D. R.

    2018-02-01

    Gravitational wave (GW) detection with pulsar timing arrays (PTAs) requires accurate noise characterization. The noise of our Galactic-scale GW detector has been systematically evaluated by the Noise Budget and Interstellar Medium Mitigation working groups within the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration. Intrinsically, individual radio millisecond pulsars (MSPs) used by NANOGrav can have some degree of achromatic red spin noise, as well as white noise due to pulse phase jitter. Along any given line-of-sight, the ionized interstellar medium contributes chromatic noise through dispersion measure (DM) variations, interstellar scintillation, and scattering. These effects contain both red and white components. In the future, with wideband receivers, the effects of frequency-dependent DM will become important. Having anticipated and measured these diverse sources of detector noise, the NANOGrav PTA remains well-poised to detect low-frequency GWs.

  8. Medium Modifications of Hadrons in Photon Induced Reactions

    International Nuclear Information System (INIS)

    Schadmand, S.

    2004-01-01

    Indications for in-medium modifications of hadron properties are reported from photoabsorption and meson production experiments. Strong medium modifications are observed in inclusive photoabsorption experiments and theoretical models investigate the in-medium dynamics of baryon resonances and their coupling to mesons. Recent experiments study the in-medium behavior of scalar and vector mesons where theoretical models expect in-medium modifications of the meson spectral functions that might be connected to partial restoration of chiral symmetry

  9. Sliding through a superlight granular medium.

    Science.gov (United States)

    Pacheco-Vázquez, F; Ruiz-Suárez, J C

    2009-12-01

    We explore the penetration dynamics of an intruder in a granular medium composed of expanded polystyrene spherical particles. Three features distinguish our experiment from others studied so far in granular physics: (a) the impact is horizontal, decoupling the effects of gravity and the drag force; (b) the density of the intruder rho(i) is up to 350 times larger than the density of the granular medium rho(m); and (c) the way the intruder moves through the material, sliding at the bottom of the column with small friction. Under these conditions we find that the final penetration D scales with (rho(i)/rho(m)) and the drag force Fd and D saturate with the height of the granular bed.

  10. Teaching in English-medium programmes

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.; Cozart, Stacey Marie

    This contribution describes and discusses the module Teaching in English-medium programmes, an elective module offered as part of the teacher training programme for assistant professors (“adjunktpædagogikum”) at Aarhus University. In order to complete the whole programme, assistant professors must...... have at least one such elective module (http://upnet.au.dk/adjunktkursus/). Aarhus University offers the teacher training programme in Danish and in English for international faculty. Teaching in English-medium programmes is part of the Danish track, but taught through English. Building...... on the foundation module in the whole course, this particular module has been established especially for those Danish assistant professors who are to teach in the EMI programmes. The intended learning outcomes are that, at the end of the course, participants should be able to plan and deliver their teaching...

  11. On accretion from an inhomogeneous medium

    International Nuclear Information System (INIS)

    Davies, R.E.; Pringle, J.E.

    1980-01-01

    Hypersonic accretion flow in two dimensions from an infinite medium which contains a small density and/or velocity gradient is considered. To first order in rsub(a)/h, where rsub(a) is the accretion radius and h the scale of the gradient, the accretion rate is unaffected and the accreted angular momentum is zero. Thus previous estimates of the amount of angular momentum accreted may severely overestimate the actual value. (author)

  12. Exploring medium effects on the nuclear force

    International Nuclear Information System (INIS)

    Sammarruca, F.

    2004-01-01

    This STI product contains a description of results from theoretical studies in nuclear physics. The goal is a systematic investigation of the nuclear force in the nuclear medium. The problems addressed are: density-dependent effective interactions as seen through proton-nucleus reactions, nuclear matter with unequal densities of protons and neutrons, applications to asymmetric nuclei through predictions of neutron radii and neutron skins

  13. El Naschie's coherence on the subquantum medium

    International Nuclear Information System (INIS)

    Agop, M.; Ioannou, P.D.; Nica, P.; Galusca, G.; Stefan, M.

    2005-01-01

    In the hydrodynamic formulation of the Scale Relativity theory one shows that a stable vortices distribution of bipolaron type induces superconducting pairs by means of the quantum potential. One builds the superconducting fractal by an iterated map and demonstrates that the superconducting pairs results as projections of this fractal. Thus, usual mechanisms (as example the exchange interaction used in the bipolaron theory) are reduced to the coherence on the subquantum medium in a ε (∞) space (El Naschie's coherence)

  14. Medium-energy ion reflection from solids

    CERN Document Server

    Mashkova, ES

    1985-01-01

    ``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

  15. Optimization of medium composition for thermostable protease ...

    African Journals Online (AJOL)

    A 24 fullfactorial central composite design (CCD) was chosen to explain the combined effects of the four medium constituents; corn starch, soybean meal, glucose and yeast extract. The optimized values obtained by the statistical analysis showed that corn starch at 19.8 g/l, soybean meal at 9.7 g/l, glucose at 3.6 g/l and ...

  16. Contrast medium extravasation in intravenous urography

    Energy Technology Data Exchange (ETDEWEB)

    Tosch, U.; Becker-Gaab, C.; Hahn, D.

    1984-09-01

    Aetiology and diagnostic procedure of calyceal fornix rupture during intravenous urography are discussed. In the literature the fornix rupture is discribed as a spontaneous event - not so in the four cases presented. In two cases a sudden increase in intrapelvic pressure was due to an ureteric calculus, in the other cases an obstruction of the ureter was secondary to neoplasm. It is recommended to perform a CT as soon as a contrast medium extravasation in intravenous urography is diagnosed.

  17. Hg(+) Frequency Standards

    Science.gov (United States)

    Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2000-01-01

    In this paper we review the development of Hg(+) microwave frequency standards for use in high reliability and continuous operation applications. In recent work we have demonstrated short-term frequency stability of 3 x 10(exp -14)/nu(sub tau) when a cryogenic oscillator of stability 2-3 x 10(exp 15) was used a the local oscillator. The trapped ion frequency standard employs a Hg-202 discharge lamp to optically pump the trapped Hg(+)-199 clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg(+) ion trap based frequency standard with an extended linear ion trap (LITE) architecture which separates the optical state selection region from the clock resonance region. This separation allows the use of novel trap configurations in the resonance region since no optical pumping is carried out there. A method for measuring the size of an ion cloud inside a linear trap with a 12-rod trap is currently being investigated. At approx. 10(exp -12), the 2nd order Doppler shift for trapped mercury ion frequency standards is one of the largest frequency offsets and its measurement to the 1% level would represent an advance in insuring the very long-term stability of these standards to the 10(exp -14) or better level. Finally, we describe atomic clock comparison experiments that can probe for a time variation of the fine structure constant, alpha = e(exp 2)/2(pi)hc, at the level of 10(exp -20)/year as predicted in some Grand Unified String Theories.

  18. Medium-Term Oil Market Report 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    How much oil will the world consume in 2011? What role will OPEC play in global oil production? Will biofuels become an important part of the oil market? The International Energy Agencys (IEA) Medium-Term Oil Market Report tackles these questions, adopting a perspective that goes beyond the traditional short-term market analysis provided in the IEAs monthly Oil Market Report. Drawing on current futures curves and the investment threshold for upstream projects, the Medium-Term Oil Market Report analyses how global demand and supply balances may develop in the next five years. The forecasts look in detail at product demand and the supply potential from all the firmly planned individual upstream and downstream projects around the world. The results provide invaluable insights on vital issues such as surplus production capacity and product supply. The rapid pace of change in the oil market means that forecasts can become outdated very quickly. This interim update provides the opportunity to rebase the data and forecasts in the annual Medium-Term Oil Market Report and to discuss and analyse new issues affecting the oil industry. Policymakers, market analysts, energy experts and anyone interested in understanding and following trends in the oil market should find this report extremely useful.

  19. Dynamical Model about Rumor Spreading with Medium

    Directory of Open Access Journals (Sweden)

    Xiaxia Zhao

    2013-01-01

    Full Text Available Rumor is a kind of social remark, that is untrue, and not be confirmed, and spreads on a large scale in a short time. Usually, it can induce a cloud of pressure, anxiety, and panic. Traditionally, it is propagated by word of mouth. Nowadays, with the emergence of the internet, rumors can be spread by instant messengers, emails, or publishing. With this new pattern of spreading, an ISRW dynamical model considering the medium as a subclass is established. Beside the dynamical analysis of the model, we mainly explore the mechanism of spreading of individuals-to-individuals and medium-to-individual. By numerical simulation, we find that if we want to control the rumor spreading, it will not only need to control the rate of change of the spreader subclass, but also need to control the change of the information about rumor in medium which has larger influence. Moreover, to control the effusion of rumor is more important than deleting existing information about rumor. On the one hand, government should enhance the management of internet. On the other hand, relevant legal institutions for punishing the rumor creator and spreader on internet who can be tracked should be established. Using this way, involved authorities can propose efficient measures to control the rumor spreading to keep the stabilization of society and development of economy.

  20. Medium-Term Oil Market Report 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    How much oil will the world consume in 2012? What role will OPEC play in global oil production? Will biofuels become an important part of the oil market? How will the refinery sector cope? The International Energy Agency (IEA) Medium-Term Oil Market Report tackles these questions, adopting a perspective that goes beyond the traditional short-term market analysis provided in the IEA Oil Market Report. Drawing on current futures curves and the investment threshold for upstream projects, the Medium-Term Oil Market Report analyses how global demand and supply balances may develop. By assessing all firmly planned upstream and downstream projects worldwide, this report forecasts supply and demand potential for crude and petroleum products over the next five years. The results provide an invaluable insight into vital issues such as surplus production capacity and product supply. An essential report for all policymakers, market analysts, energy experts and anyone interested in understanding and following oil market trends, the Medium-Term Oil Market Report is a further element of the strong commitment of the IEA to improving and expanding the quality, timeliness and accuracy of energy data and analysis.

  1. Heating of the local interstellar medium

    International Nuclear Information System (INIS)

    Arnaud, M.; Rothenflug, R.

    1986-07-01

    From soft X ray measurements evidence emerges that a large volume of the local interstellar medium is filled with hot gas. The sky has now been almost entirely scanned in the soft X ray bands. Although the very contribution of a halo or/and large scale galactic components is still debated, it appears that an important part of this soft X ray emission has a local origin. Its thermal nature was strongly supported after X ray lines of some highly stripped ions were observed. This local interstellar medium is likely to have been heated by the energy released in Supernova(e) explosion(s). We review such models and discuss whether they may account for both the observed fluxes in soft X ray bands and the X ray spectral data. Special emphasis is put on the intricacy of the data, which presently makes hopeless a detailed understanding of the hot local interstellar medium. Consistency of such models with key parameters (such as OVI column density) is also studied

  2. Frequency control modelling - basics

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Sørensen, Poul Ejnar; Zeni, Lorenzo

    2016-01-01

    The purpose of this report is to provide an introduction on how the system balance in an island system can be maintained by controlling the frequency. The power balance differential equation, which is fundamental in understanding the effect on the system frequency of the unbalance between...... generation and consumption, is addressed. Basic topics on the main components of a generating unit, such generators, prime movers and governors are presented. A simple dynamic model for an island power system, containing realistic dynamic representations of generators, loads, prime movers, governors...

  3. Waves with negative group velocity. Conditions of their existence in a isotropic medium

    International Nuclear Information System (INIS)

    Makarov, V.P.; Rukhadze, A.A.; Samokhin, A.A.

    2005-01-01

    The analysis of the frequency and spatial dispersions of the dielectric permittivity and magnetic permeability of an isotropic medium are carried out in the (E-vector, B-vector, D-vector) and (E-vector, B-vector, D-vector, H-vector) approaches of electrodynamics. The conditions under which the phase and group velocities of transverse electromagnetic waves have opposite directions are clarified, and the consequences arised are discussed

  4. DC Voltage Balance Control Strategy for Medium Voltage Cascaded STATCOM Based on Distributed Control

    OpenAIRE

    Xuehua Zhao; Liping Shi

    2014-01-01

    DC bus capacitors of Medium Voltage Cascaded STATCOM are independent. DC side voltage balance control method is the key influencing factor of current control. The imbalance of DC bus voltage increases harmonic current and affects the safety of device. In this paper, the unbalance mechanism of DC side capacitor voltage is analyzed. Based on the unipolar dual frequency and carrier phase-shifted SPWM (CPS-SPWM) modulation algorithms, the distributed control algorithms, which need multi- FPGA str...

  5. Tracer transfer in consolidated porous medium and fractured porous medium: experimentations and modelling

    International Nuclear Information System (INIS)

    Dalla Costa, C.

    2007-07-01

    We try to identify and model physical and chemical mechanisms governing the water flow and the solute transport in fractured consolidated porous medium. An original experimental device was built. The 'cube' consists of an idealized fractured medium reproduced by piling up consolidated porous cubes of 5 cm edge. Meanwhile, columns of the homogeneous consolidated porous medium are studied. The same anionic tracing technique is used in both cases. Using a system analysis approach, we inject concentration pulses in the device to obtain breakthrough curves. After identifying the mass balance and the residence time, we fit the CD and the MIM models to the experimental data. The MIM model is able to reproduce experimental curves of the homogeneous consolidated porous medium better than the CD model. The mobile water fraction is in accordance with the porous medium geometry. The study of the flow rate influence highlights an interference dispersion regime. It was not possible to highlight the observation length influence in this case. On the contrary, we highlight the effect of the observation scale on the fractured and porous medium, comparing the results obtained on a small 'cube' and a big 'cube'. The CD model is not satisfactory in this case. Even if the MIM model can fit the experimental breakthrough curves, it was not possible to obtain unique parameters for the set of experiments. (author)

  6. ACOUSTIC WAVES EMISSION IN THE TWO-COMPONENT HEREDITARY-ELASTIC MEDIUM

    Directory of Open Access Journals (Sweden)

    V. S. Polenov

    2014-01-01

    Full Text Available Summary. On the dynamics of two-component media a number of papers, which address the elastic waves in a homogeneous, unbounded fluid-saturated porous medium. In other studies address issues of dissipative processes in harmonic deformation hereditary elastic medium. In the article the dissipative processes of the viscoelastic porous medium, which hereditary properties are described by the core relaxation fractional exponential function U.N. Rabotnova integro-differential Boltzmann-Volterr ratio, harmonic deformation by the straining saturated incompressible liquid are investigated. Speed of wave propagation, absorption coefficient, mechanical loss tangent, logarithmic decrement, depending on fractional parameter γ, determining formulas received. The frequency logarithm and temperature graph dependences with the goal fractional parameter are constructed. Shows the dependences velocity and attenuation coefficient of the tangent of the phase angle of the logarithm of the temperature, and the dependence of the attenuation coefficient of the logarithm of the frequency. Dependencies the speed and the tangent of the phase angle of the frequency identical function of the logarithm of temperature.

  7. Tunable dual-band subwavelength imaging with a wire medium slab loaded with nanostructured graphene metasurfaces

    Directory of Open Access Journals (Sweden)

    Ali Forouzmand

    2015-07-01

    Full Text Available In this paper, we demonstrate that a wire medium slab loaded with graphene-nanopatch metasurfaces (GNMs enables the enhancement of evanescent waves for the subwavelength imaging at terahertz (THz frequencies. The analysis is based on the nonlocal homogenization model for wire medium with the additional boundary condition at the connection of wires to graphene. The physical mechanism behind this lens can be described as the surface plasmons excitement at the lower and upper GNMs which are coupled by an array of metallic wires. The dual nature (capacitive/inductive of the GNM is utilized in order to design a dual-band lens in which the unique controllable properties of graphene and the structural parameters of wire medium (WM slab provide more degrees of freedom in controlling two operating frequency bands. The lens can support the subwavelength imaging simultaneously at two tunable distinct frequencies with the resolution better than λ/6 even if the distance between GNMs is a significant fraction of wavelength (>λ/5.5. The major future challenges in the fabrication of the lens have been demonstrated and a promising approach for the practical configuration of the lens has been proposed.

  8. Low frequency radioastronomy

    International Nuclear Information System (INIS)

    Zarka, Philippe; Cecconi, Baptiste; Tagger, Michel; Torchinsky, Steve; Picard, Philippe; Pezzani, Jacques; Cognard, Ismael; Boone, Frederic; Woan, Graham; Weber, Rodolphe; Gousset, Thierry; Lautridou, Pascal; Dallier, Richard

    2011-07-01

    Low frequency radioastronomy deals with the direct detection (below 100 MHz) and heterodyne detection (up to few GHz) of electromagnetic waves (phase and amplitude) followed by a time or spectral analysis. The 30. Goutelas school covered several aspects of radioastronomy involving various aspects of physics: non-thermal phenomena in plasmas and physics of magnetized plasmas, atomic and molecular physics, and particle physics. These proceedings comprise 17 lectures dealing with: 1 - Low-Frequency Radioastronomy Basics (P. Zarka); 2 - Radioastronomy Historical Highlights (S. A. Torchinsky); 3 - Antennas (P. Picard, J. Pezzani); 4 - Receptors (P. Picard, J. Pezzani); 5 - Pulsars chronometry: metrology in radioastronomy (I. Cognard); 6 - Interferometry as imaging technique (F. Boone); 7 - Radio propagation and scintillation (G. Woan); 8 - Square Kilometer Array (S. A. Torchinsky); 9 - Techniques against radio-electrical interferences in low-frequency radioastronomy (R. Weber); 10 - Introduction to poly-phase filtering (R. Weber); 11 - Three decades of Jupiter's radio-emission studies: from the Nancay deca-meter network to LOFAR (P. Zarka); 12 - Atmospheric showers and their radio counterpart (T. Gousset); 13 - From cosmic rays radio-detection to pulse radioastronomy (P. Lautridou, R. Dallier); 14 - The CODALEMA project (R. Dallier, P. Lautridou); 15 - Space-based radio measurements: Gonio-polarimetry (B. Cecconi); 16 - Radio astronomy from space (G. Woan); 17 - LOFAR: the Low Frequency Array and the French FLOW consortium (M. Tagger, P. Zarka)

  9. Frequency and turmoil

    African Journals Online (AJOL)

    level of popular unrest focused on 'service delivery protests', but in recent years the broader conception of ... Drawing on the Centre for Social Change's archive of media reports, the largest database of its kind, and by comparing its data with .... impact on frequencies. The variation evident in the table is not accidental but is ...

  10. Radio Frequency Identification

    Indian Academy of Sciences (India)

    Radio Frequency Identification (RFID) has been around sinceearly 2000. Its use has currently become commonplace as thecost of RFID tags has rapidly decreased. RFID tags have alsobecome more 'intelligent' with the incorporation of processorsand sensors in them. They are widely used now in manyinnovative ways.

  11. Radio Frequency Identification

    Indian Academy of Sciences (India)

    collection and accounting daily, London commuter system uses the data gathered by the central computer to optimize scheduling of trains and buses. With millions of cards in use, the cost of an oyster card with an RFID tag is amortized by the fare collected. The system is a near-field system using low-frequency tags. 3.

  12. High frequency electromagnetic dosimetry

    CERN Document Server

    Sánchez-Hernández, David A

    2009-01-01

    Along with the growth of RF and microwave technology applications, there is a mounting concern about the possible adverse effects over human health from electromagnetic radiation. Addressing this issue and putting it into perspective, this groundbreaking resource provides critical details on the latest advances in high frequency electromagnetic dosimetry.

  13. Metamaterial for Radar Frequencies

    Science.gov (United States)

    2012-09-01

    capacitive coupling with adjacent patches, as shown in Figure 3. The via provides inductance to ground. Figure 3. (a) Planar LH distributed periodic...After [20]). The capacitance in the structure balances out the inductance present when the cylinder is placed in a square array. The metallic... RADAR FREQUENCIES by Szu Hau Tan September 2012 Thesis Advisor: David C. Jenn Second Reader: James Calusdian

  14. Embryo quality and implantation rate in two different culture media: ISM1 versus Universal IVF Medium.

    Science.gov (United States)

    Xella, Susanna; Marsella, Tiziana; Tagliasacchi, Daniela; Giulini, Simone; La Marca, Antonio; Tirelli, Alessandra; Volpe, Annibale

    2010-04-01

    To compare the outcome of two different culture media marketed by the MediCult AS Company (Jyllinge, Denmark)-Universal IVF Medium and ISM1 Medium culture-which, in addition to glucose, pyruvate, and energy-providing components, also contain amino acids, nucleotides, vitamins, and cholesterol. Laboratory and retrospective clinical study. University teaching hospital. A total of 726 patients, undergoing IVF-intracytoplasmic sperm injection procedure, comparable in mean age range, oocyte retrieval, and infertility indication, were included in the study. Laboratory quality and standard procedures were maintained unaffected. Oocyte retrieval, different embryo culture media. Embryo quality, ongoing pregnancy, and implantation rate. The frequency of good-quality embryos (79% vs. 74%) and the percentages of ongoing pregnancy (27.5% vs. 18%) and implantation rate (15% vs. 10%) were significantly higher in the group treated with ISM1 Medium rather than Universal IVF Medium. ISM1 Medium culture seems to improve the performance of embryonic growth and development, as well as increasing the percentage of pregnancy. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  15. System and method for monitoring water content or other dielectric influences in a medium

    Science.gov (United States)

    Cherry, Robert S.; Anderson, Allen A.

    2001-01-01

    A sensor system is provided that measures water content or other detectable properties in a medium along the entire length of the sensor at any point in time. The sensor system includes an electromagnetic signal generator and a transmission line disposed in a medium to be monitored. Alternatively, the transmission line can be configured for movement across a medium to be monitored, or the transmission line can be fixed relative to a moving medium being monitored. A signal is transmitted along the transmission line at predetermined frequencies, and the signal is returned back along the transmission line and/or into an optional receive line in proximity to the transmission line. The returned signal is processed to generate a one-dimensional data output profile that is a function of a detectable property of the medium. The data output profile can be mapped onto a physical system to generate a two-dimensional or three-dimensional profile if desired. The sensor system is useful in a variety of different applications such as agriculture, horticulture, biofiltration systems for industrial offgases, leak detection in landfills or drum storage facilities at buried waste sites, and in many other applications.

  16. Localization of a small change in a multiple scattering environment without modeling of the actual medium.

    Science.gov (United States)

    Rakotonarivo, S T; Walker, S C; Kuperman, W A; Roux, P

    2011-12-01

    A method to actively localize a small perturbation in a multiple scattering medium using a collection of remote acoustic sensors is presented. The approach requires only minimal modeling and no knowledge of the scatterer distribution and properties of the scattering medium and the perturbation. The medium is ensonified before and after a perturbation is introduced. The coherent difference between the measured signals then reveals all field components that have interacted with the perturbation. A simple single scatter filter (that ignores the presence of the medium scatterers) is matched to the earliest change of the coherent difference to localize the perturbation. Using a multi-source/receiver laboratory setup in air, the technique has been successfully tested with experimental data at frequencies varying from 30 to 60 kHz (wavelength ranging from 0.5 to 1 cm) for cm-scale scatterers in a scattering medium with a size two to five times bigger than its transport mean free path. © 2011 Acoustical Society of America

  17. Food frequency questionnaires.

    Science.gov (United States)

    Pérez Rodrigo, Carmen; Aranceta, Javier; Salvador, Gemma; Varela-Moreiras, Gregorio

    2015-02-26

    Food Frequency Questionnaires are dietary assessment tools widely used in epidemiological studies investigating the relationship between dietary intake and disease or risk factors since the early '90s. The three main components of these questionnaires are the list of foods, frequency of consumption and the portion size consumed. The food list should reflect the food habits of the study population at the time the data is collected. The frequency of consumption may be asked by open ended questions or by presenting frequency categories. Qualitative Food Frequency Questionnaires do not ask about the consumed portions; semi-quantitative include standard portions and quantitative questionnaires ask respondents to estimate the portion size consumed either in household measures or grams. The latter implies a greater participant burden. Some versions include only close-ended questions in a standardized format, while others add an open section with questions about some specific food habits and practices and admit additions to the food list for foods and beverages consumed which are not included. The method can be self-administered, on paper or web-based, or interview administered either face-to-face or by telephone. Due to the standard format, especially closed-ended versions, and method of administration, FFQs are highly cost-effective thus encouraging its widespread use in large scale epidemiological cohort studies and also in other study designs. Coding and processing data collected is also less costly and requires less nutrition expertise compared to other dietary intake assessment methods. However, the main limitations are systematic errors and biases in estimates. Important efforts are being developed to improve the quality of the information. It has been recommended the use of FFQs with other methods thus enabling the adjustments required. Copyright AULA MEDICA EDICIONES 2015. Published by AULA MEDICA. All rights reserved.

  18. Financial management practices in successful Small and Medium Enterprises (SMEs

    Directory of Open Access Journals (Sweden)

    Hendrik Petrus Wolmarans

    2015-07-01

    Full Text Available Although the success of small, medium and micro enterprises (SMEs is extremely important for the South African economy, their failure rate is amongst the highest in the world; some researchers estimate as high as 90 percent. Research has shown that the lack of financial management skills and application of financial management practices are some of the biggest factors contributing to SME failure. However, it is not clear from the literature which of these skills and practices are more important than others. This study aims to fill this gap by determining which financial management skills are relevant for successful SMEs. A survey was done on a sample of owner-managers of successful SMEs who had been asked, firstly, whether they performed different financial management practices and, secondly, how frequently they performed these in their companies. The study concludes that practices regarding working capital as well as profitability are much more relevant than those regarding a balance sheet or strategic finance. Similarly, financial practices related to cash flow and decision making are more relevant than those related to planning or analysing. It may be true, due to the high risk and volatile environment of SMEs, as well as the challenges that are often underestimated, that financial practices which academics regard as important are not always implemented by these companies.  This study contributes to the existing body of knowledge as it determines the relative relevance and frequency of use of financial management practices by successful SMEs. KEY WORDS Small and medium enterprises, Financial management practices, Successful SMEs, Entrepreneurship education

  19. Importance of Including the Acoustic Medium in Rooms on the Transmission Path between Source and Receiver Rooms within a Building

    DEFF Research Database (Denmark)

    Andersen, Lars; Kirkegaard, Poul Henning; Dickow, Kristoffer Ahrens

    2011-01-01

    Low-frequency noise is a potential nuisance to inhabitants in lightweight building structures. Hence, development of efficient and accurat methods for prediction of noice in such buildings is important. The aim of this paper is to assess the necessity of including the acoustic medium in rooms along...

  20. Medium energy hadron scattering from nuclei

    International Nuclear Information System (INIS)

    Ginocchio, J.N.; Wenes, G.

    1986-01-01

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154 Sm and 154 Gd. 27 refs., 5 figs., 1 tab

  1. Superluminous laser pulse in an active medium

    International Nuclear Information System (INIS)

    Fisher, D.L.; Tajima, T.

    1993-12-01

    Physical conditions are obtained to make the propagation velocity of a laser pulse and thus the phase velocity of the excited wake be at any desired value, including that equal to or greater than the speed of light. The provision of an active-plasma laser medium with an appropriately shaped pulse allows not only replenishment of laser energy loss to the wakefield but also acceleration of the group velocity of photons. A stationary solitary solution in the accelerated frame is obtained from the model equations and simulations thereof for the laser, plasma and atoms. This approach has applications in photonics and telecommunications as well as wakefield accelerators

  2. Cooperative networking in a heterogeneous wireless medium

    CERN Document Server

    Ismail, Muhammad

    2013-01-01

    This brief focuses on radio resource allocation in a heterogeneous wireless medium. It presents radio resource allocation algorithms with decentralized implementation, which support both single-network and multi-homing services. The brief provides a set of cooperative networking algorithms, which rely on the concepts of short-term call traffic load prediction, network cooperation, convex optimization, and decomposition theory. In the proposed solutions, mobile terminals play an active role in the resource allocation operation, instead of their traditional role as passive service recipients in the networking environment.

  3. A medium energy neutron deep penetration experiment

    International Nuclear Information System (INIS)

    Amian, W.; Cloth, P.; Druecke, V.; Filges, D.; Paul, N.; Schaal, H.

    1986-11-01

    A deep penetration experiment conducted at the Los Alamos WNR facility's Spallation Neutron Target is compared with calculations using intra-nuclear-cascade and S N -transport codes installed at KFA-IRE. In the experiment medium energy reactions induced by neutrons between 15 MeV and about 150 MeV inside a quasi infinite slab of iron have been measured using copper foil monitors. Details of the experimental procedure and the theoretical methods are described. A comparison of absolute reaction rates for both experimentally and theoretically derived reactions is given. The present knowledge of the corresponding monitor reaction cross sections is discussed. (orig.)

  4. Electromagnetically Induced Transparency In Rydberg Atomic Medium

    Science.gov (United States)

    Deng, Li; Cong, Lu; Chen, Ai-Xi

    2018-03-01

    Due to possessing big principal quantum number, Rydberg atom has some unique properties, for example: its radiative lifetime is long, dipole moment is large, and interaction between atoms is strong and so on. These properties make one pay attention to Rydberg atoms. In this paper we investigate the effects of Rydberg dipole-dipole interactions on electromagnetically induced transparency (EIT) schemes and group velocity in three-level systems of ladder type, which provides theoretical foundation for exploring the linear and nonlinear characteristics of light in a Rydberg electromagnetically-induced-transparency medium.

  5. Adiabatic supernova expansion into the circumstellar medium

    International Nuclear Information System (INIS)

    Band, D.L.; Liang, E.P.

    1987-01-01

    We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs

  6. Photodegradation of organophosphorus pesticides in honey medium.

    Science.gov (United States)

    Yuan, Zhimin; Yao, Jun; Liu, Haijun; Han, Jun; Trebše, Polonca

    2014-10-01

    Honey can be polluted due to environmental pollution and misuse of beekeeping practices. In the present study, photodegradation experiments of organophosphorus pesticides (coumaphos, methyl parathion and fenitrothion) in honey medium were conducted using Atlas Suntest simulator CPS+ as a sunlight producer. Photodegradation experiments were conducted under three different intensities as 250W/m(2), 500W/m(2) and 750W/m(2) to evaluate the impact of sunlight intensity on removal of OPs in honey medium. Significant decreases of three OPs' concentrations were observed. Coumaphos showed the highest degradability, reaching a degradation percentage of 90 percent within 15min. After 1h irradiation, residual percentages of coumaphos were 6.62 percent for 250W/m(2), 3.48 percent for 500W/m(2) and 2.98 percent for 750W/m(2), respectively. Methyl parathion and fenitrothion also could be removed through photodegradation efficiently. After 1h irradiation, the residual percentages of methyl parathion and fenitrothion under 750W/m(2) sunlight irradiation were 26.89 percent and 16.70 percent, respectively. Intensity of sunlight showed a positive impact on removal of OPs in honey medium. The higher intensity, the lower residual percentage. Photodegradation of three OPs fitted well with pseudo-first order kinetics. Half-lives calculated from pseudo-first order kinetics were 17.61min (250W/m(2)), 16.67min (500W/m(2)) and 17.58min (750W/m(2)) for coumaphos, 57.62min (250W/m(2)), 34.13min (500W/m(2)) and 31.69min (750W/m(2)) for methyl parathion and 144.70min (250W/m(2)), 95.47min (500W/m(2)) and 22.57min (750W/m(2)) for fenitrothion, respectively. Most of the three OPs could dissipate in a short time under sunlight irradiation. Photodegradation could be accepted as an appropriate method for the removal of OPs in honey medium. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Electromagnetic properties of neutrinos in a medium

    International Nuclear Information System (INIS)

    Nieves, J.F.; Pal, P.B.

    1989-01-01

    We show that, contrary to the situation in the vacuum, a Majorana neutrino can have electric and magnetic dipole moments in a medium. This is because of new contributions, equal for a particle and its antiparticle, that can arise only in a material background. For Dirac neutrinos, these contributions make the magnitudes of the dipole moments of the particle and the antiparticle unequal. We discuss the conditions which give rise to such effects, with particular attention to the role played by the discrete symmetries C, P, and T

  8. Polyelectrolyte as solvent and reaction medium.

    Science.gov (United States)

    Prescher, Simon; Polzer, Frank; Yang, Yan; Siebenbürger, Miriam; Ballauff, Matthias; Yuan, Jiayin

    2014-01-08

    A poly(ionic liquid) with a rather low glass transition temperature of -57°C was synthesized via free radical polymerization of an acrylate-type ionic liquid monomer. It exhibits fluidic behavior in a wide temperature range from room temperature to the threshold of the thermal decomposition. We demonstrate that it could act as a unique type of macromolecular solvent to dissolve various compounds and polymers and separate substances. In addition, this polyelectrolyte could serve successfully as reaction medium for catalysis and colloid particle synthesis. The synergy in the solvation and stabilization properties is a striking character of this polymer to downsize the in situ generated particles.

  9. Relativistic energy loss in a dispersive medium

    DEFF Research Database (Denmark)

    Houlrik, Jens Madsen

    2002-01-01

    The electron energy loss in a dispersive medium is obtained using macroscopic electrodynamics taking advantage of a static frame of reference. Relativistic corrections are described in terms of a dispersive Lorentz factor obtained by replacing the vacuum velocity c by the characteristic phase...... velocity c/n, where n is the complex index of refraction. The angle-resolved energy-loss spectrum of a Drude conductor is analyzed in detail and it is shown that the low-energy peak due to Ohmic losses is enhanced compared to the classical approximation....

  10. Bildung in the Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael Eric

    We are living in a period where new social structures arise in the communicative space and wake of digital media. This means that we must try to adapt to a changing social world within all social arenas like economy, work-life, love relations and last but not least education. The question...... of this paper is what Bildung should be or could be within this new medium environment. It draws on Luhmann (2006), Biesta (2006), Klafki (2014) and Kant (1784) describing what Bildung is seen from the view of the enlightenment tradition and try to discuss and analyze how ideas of Bildung could be used...

  11. Distributed medium access control in wireless networks

    CERN Document Server

    Wang, Ping

    2013-01-01

    This brief investigates distributed medium access control (MAC) with QoS provisioning for both single- and multi-hop wireless networks including wireless local area networks (WLANs), wireless ad hoc networks, and wireless mesh networks. For WLANs, an efficient MAC scheme and a call admission control algorithm are presented to provide guaranteed QoS for voice traffic and, at the same time, increase the voice capacity significantly compared with the current WLAN standard. In addition, a novel token-based scheduling scheme is proposed to provide great flexibility and facility to the network servi

  12. The question of caution in professional medium

    International Nuclear Information System (INIS)

    Godard, O.

    2006-01-01

    Contrived in Europe to tackle the environment protection policies and management of natural resources, the principle of caution has seen since 1990 its interest developed towards the fields of food safety and public health. The importance and the relevance of questions have lead the national institute of research and safety to constitute a working group to explore the problems and the potentialities that could be linked to the explicit introduction of this principle and this in the field of the prevention of professional risks. This work tackles several aspects of the question of caution in professional medium such history, concepts, evolution...as well as cases judged exemplary ones. (N.C.)

  13. The Casimir effect: medium and geometry

    International Nuclear Information System (INIS)

    Marachevsky, Valery N

    2012-01-01

    Theory of the Casimir effect is presented in several examples. Casimir–Polder-type formulas, Lifshitz theory and theory of the Casimir effect for two gratings separated by a vacuum slit are derived. Equations for the electromagnetic field in the presence of a medium and dispersion are discussed. The Casimir effect for systems with a layer of 2 + 1 fermions is studied. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (paper)

  14. Heat Transfer in a Semitransparent Medium

    Science.gov (United States)

    Shamparov, E. Yu.

    2018-01-01

    The problem of 1D radiative-conductive heat transfer in a homogeneous isotropic gray medium near a planar diffuse nontransparent surface and in between parallel plates with different temperatures has been solved analytically. Nonconvective measurements of the thermal resistance of parallel-plane polyethylene foam specimens versus the number of layers (i.e., thickness) have been taken, both without and with thin screens made of aluminum foil. The applicability of the suggested theoretical approach and experimental technique for the measurement of radiative heat transfer and heat transfer by conduction in light heat-protective materials has been demonstrated.

  15. Interactions between intergalactic medium and galaxies

    International Nuclear Information System (INIS)

    Einasto, J.; Saar, E.

    1977-01-01

    The interaction of galaxies with the environmental gas both in clusters and in small groups of galaxies is investigated. Interaction between galaxies and the ambient medium can be considered simply as final touches in the process of galaxy formation. Large relative velocities of galaxies in their clusters and of the intercluster gas result in a loss of the intergalactic gas, that in its turn affects the morphology of cluster galaxies. Interaction between the coronal clouds and the gas in the disk of spiral galaxies may result in regular patterns of star formation and in the bending of planes of galaxies

  16. Radio frequency ion source

    CERN Document Server

    Shen Guan Ren; Gao Fu; LiuNaiYi

    2001-01-01

    The study on Radio Frequency Ion Source is mainly introduced, which is used for CIAE 600kV ns Pulse Neutron Generator; and obtained result is also presented. The RF ion source consists of a diameter phi 25 mm, length 200 mm, coefficient of expansion =3.5 mA, beam current on target >=1.5 mA, beam spot =100 h.

  17. Low-frequency dilatational wave propagation through unsaturated porous media containing two immiscible fluids

    Energy Technology Data Exchange (ETDEWEB)

    Lo, W.-C.; Sposito, G.; Majer, E.

    2007-02-01

    An analytical theory is presented for the low-frequency behavior of dilatational waves propagating through a homogeneous elastic porous medium containing two immiscible fluids. The theory is based on the Berryman-Thigpen-Chin (BTC) model, in which capillary pressure effects are neglected. We show that the BTC model equations in the frequency domain can be transformed, at sufficiently low frequencies, into a dissipative wave equation (telegraph equation) and a propagating wave equation in the time domain. These partial differential equations describe two independent modes of dilatational wave motion that are analogous to the Biot fast and slow compressional waves in a single-fluid system. The equations can be solved analytically under a variety of initial and boundary conditions. The stipulation of 'low frequency' underlying the derivation of our equations in the time domain is shown to require that the excitation frequency of wave motions be much smaller than a critical frequency. This frequency is shown to be the inverse of an intrinsic time scale that depends on an effective kinematic shear viscosity of the interstitial fluids and the intrinsic permeability of the porous medium. Numerical calculations indicate that the critical frequency in both unconsolidated and consolidated materials containing water and a nonaqueous phase liquid ranges typically from kHz to MHz. Thus engineering problems involving the dynamic response of an unsaturated porous medium to low excitation frequencies (e.g. seismic wave stimulation) should be accurately modeled by our equations after suitable initial and boundary conditions are imposed.

  18. Heating systems with PLC and frequency control

    Energy Technology Data Exchange (ETDEWEB)

    Abdallah, S.; Abu-Malouh, R. [Applied Science Univ., Amman (Jordan). Dept. of Mechanical and Industrial Engineering

    2007-07-01

    Heat treatment involves the controlled heating and cooling of metals to alter their physical and mechanical properties without changing the product shape. Heat treatment is frequently associated with increasing the strength of material, but it can also be utilized to alter certain manufacturability objectives such as improve machining, improve formability, and restoring ductility after a cold working operation. Heat treatment is an enabling process that can help other manufacturing processes, as well as improve product performance by increasing strength or other desirable characteristics. This paper discussed the design and construction of a medium capacity controlled heating system. The programming method of control of the heating process was achieved using an integrated programmable logic controller (PLC) and frequency inverter. An experimental study was performed to investigate the effect of temperature and tempering time on hardness and fatigue resistance of 0.4 per cent carbon steel. The paper discussed the heating system design and control and provided a mathematical description of the frequency controlled heating system. The modeling of the frequency converter and of the furnace was explained. It was concluded that increasing the tempering temperature above 550 degrees Celsius or tempering time decreased the hardness of the material. 26 refs., 16 figs.

  19. Filamentary fragmentation in a turbulent medium

    Science.gov (United States)

    Clarke, S. D.; Whitworth, A. P.; Duarte-Cabral, A.; Hubber, D. A.

    2017-06-01

    We present the results of smoothed particle hydrodynamic simulations investigating the evolution and fragmentation of filaments that are accreting from a turbulent medium. We show that the presence of turbulence and the resulting inhomogeneities in the accretion flow play a significant role in the fragmentation process. Filaments that experience a weakly turbulent accretion flow fragment in a two-tier hierarchical fashion, similar to the fragmentation pattern seen in the Orion Integral Shaped Filament. Increasing the energy in the turbulent velocity field results in more sub-structure within the filaments, and one sees a shift from gravity-dominated fragmentation to turbulence-dominated fragmentation. The sub-structure formed in the filaments is elongated and roughly parallel to the longitudinal axis of the filament, similar to the fibres seen in observations of Taurus, and suggests that the fray and fragment scenario is a possible mechanism for the production of fibres. We show that the formation of these fibre-like structures is linked to the vorticity of the velocity field inside the filament and the filament's accretion from an inhomogeneous medium. Moreover, we find that accretion is able to drive and sustain roughly sonic levels of turbulence inside the filaments, but is not able to prevent radial collapse once the filaments become supercritical. However, the supercritical filaments that contain fibre-like structures do not collapse radially, suggesting that fibrous filaments may not necessarily become radially unstable once they reach the critical line-density.

  20. Dielectrophoresis of spermatozoa in viscoelastic medium.

    Science.gov (United States)

    Koh, James Boon Yong; Marcos

    2015-07-01

    Knowledge of spermatozoa motility is important in selecting suitable spermatozoa for assisted reproduction procedures. By considering the internal sliding force within an active filament, its shape in a viscoelastic Oldroyd-B fluid subjected to nonuniform electric field is presented. The resulting velocity is a function of the beating pattern and DEP force, which is dependent on the spermatozoon's morphology as well as the gradient of the mean square electric field. Finally, the velocities of the X- and Y-spermatozoa are compared under various conditions of nonuniform electric field and viscoelasticity of the medium. The presence of DEP force alters their velocities to different extents, giving an 84% level of confidence for selecting spermatozoon that contains the chromosome leading to a female. Therefore, a nonuniform electric field can be used not only to sort and select spermatozoa of desired morphology, but also for gender selection. Moreover, we found that sorting in a viscoelastic fluid medium is more effective as the effect of DEP on the spermatozoa velocity is enhanced by an order of magnitude. © 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. INNOVATIVE CULTURE IN SMALL AND MEDIUM ENTERPRISES

    Directory of Open Access Journals (Sweden)

    Aluisio Broering Mambrini

    2011-10-01

    Full Text Available In the last two decades, innovation has been a key driver of economic growth. Innovation is closely related to creating value and generating wealth through successful service to consumer needs. Thus, it is not necessarily restricted to the use of new knowledge generated from research, but on the development of new products or services that are obtained with creative use of knowledge, new or already known. This study aimed to identify management practices that promote a culture of innovation in small and medium enterprises and analyze how they contribute to the innovative capacity of these companies. The research method was the multiple case study with six small and medium businesses that have at least one case of significant innovation in its history. The main results showed that amongst the practices are: a performance in highly specialized niches and deep focus on customer needs; b strong investment and incorporation of new knowledge outside the company (open innovation; c speed and agility in the absorption and deployment of new knowledge and technologies; d retention of employees; e acting as an integrator combining diverse knowledge and technologies; f the information management of the knowledge acquired by the company; g little concern to patent the technology; h flexibility and informal, fluid and open communication between employees of the company that promotes agility in management and i the management of partnerships across the value chain, including the functional areas.

  2. Medium-size power plants. Economic options

    International Nuclear Information System (INIS)

    Vogelweith, L.; Baujat, J.; Goutail, J.

    1978-01-01

    In this paper the authors describe a method for economic evaluation of a nuclear power plant project such as advocated by the IAEA but modified through the introduction of various parameters that may affect the evaluation, i.e. the weighted evaluation rate, the annual increase in the cost of fuel, and the discount rate. The method is applied to barge-based medium-size reactors (125 MW(e)). The authors calculate the investment cost, together with the costs of administration, operation and maintenance; use is made of current assumptions regarding the price of fuel for the case of a reference nuclear plant and an oil-fired plant of the same power and in the same programme. In this way the authors derive the discounted cost of the nuclear programme and concurrent conventional programme on the basis of the following assumptions: a weighted inflation rate varying between 0 and 6% per year; an annual increase in real fuel prices ranging from 0 to 3%; and a real discount rate, equal to the real interest rate, varying between 4 and 7% per year and corresponding to nominal discount rates of up to 13.4%. The conclusion reached is that, given the real interest rates actually prevailing on the financial market, a weighted inflation rate foreseen by the majority of experts, and a rise in real fuel prices of the order of 1% per year, the medium-size nuclear power plant is more economical than a conventional plant of the same output. (author)

  3. Shock propagation in a heterogeneous medium

    International Nuclear Information System (INIS)

    Elbaz, D.

    2011-01-01

    In the frame of the inertial confinement fusion in direct drive, the use of foams as ablator allows the reduction of hydrodynamic instabilities created on the target by the direct laser irradiation. The foam is made up of carbon (CH) fibers impregnated of cryogenic deuterium-tritium (DT). In the past, studies have been carried out considering this foam to be a homogeneous medium. Yet, the foam presents heterogeneous features. We study the effects of this heterogeneity on the shock velocity when the laser irradiates the target. Thanks to experimental and numerical studies, we show that the shock propagates faster in the heterogeneous medium than in the homogeneous one with the same averaged density. This velocity gap depends on the presence rate of the CH fibers in the foam, the density ratio, the adiabatic coefficient and the foam geometry. We model the foam by different ways, more and more complex. The shock velocity modification is due to the baroclinicity which, during the interaction between the shock front and the interface, creates a vorticity deposition, responsible for the shock acceleration. Accordingly, an interface, which is plane and perpendicular to the front shock, maximizes the vorticity deposition and increases the velocity gaps between heterogeneous and homogeneous media. We found a correlation between the kinetic energy behind the shock front and the velocities relative difference. We compared our results with two analytical models. However, the system is not closed, so we can't for the moment develop a predictive model. (author) [fr

  4. Formation of Benzene in the Interstellar Medium

    Science.gov (United States)

    Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.; Crim, F. Fleming (Editor)

    2010-01-01

    Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block-the aromatic benzene molecule-has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3- butadiene, C2H + H2CCHCHCH2 --> C6H6, + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadlene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium.

  5. Characterisation of Ferrosilicon Dense Medium Separation Material

    International Nuclear Information System (INIS)

    Waanders, F. B.; Mans, A.

    2003-01-01

    Ferrosilicon is used in the dense medium separation of iron ore at Kumba resources, Sishen, South Africa. Due to high cost and losses that occur during use, maximum recovery by means of magnetic separation is aimed for. The purpose of this project was to determine the characteristics of the unused Fe-Si and then to characterise the changes that occur during storage and use thereof. Scanning electron microscopy was used to determine the composition of each sample, whilst Moessbauer spectroscopy yielded a two-sextet spectrum with hyperfine magnetic field strengths of 20 and 31 T, respectively, for the fresh samples. Additional hematite oxide peaks appeared in the Moessbauer spectra after use of the Fe-Si over a length of time, but this did not result in a dramatic degradation of the medium. No definite changes occurred during correct storage methods. It was, however, found that the biggest loss of Fe-Si was due to the abrasion of the particles, which resulted in the formation of an oxihydroxide froth, during the process.

  6. Formation of benzene in the interstellar medium

    Science.gov (United States)

    Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.

    2011-01-01

    Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block—the aromatic benzene molecule—has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3-butadiene, C2H + H2CCHCHCH2 → C6H6 + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadiene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium. PMID:21187430

  7. GABA interaction with lipids in organic medium

    International Nuclear Information System (INIS)

    Beltramo, D.; Kivatinitz, S.; Lassaga, E.; Arce, A.

    1987-01-01

    The interaction of 3 H-GABA and 14 C-glutamate with lipids in an aqueous organic partition system was studied. With this partition system 3 H-GABA and 14 C-glutamate were able to interact with sphingomyelin, sulfatide, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine and phosphatidic acid but not with cholesterol or ceramide. In an homogeneous aqueous medium the authors could not demonstrate any interaction between 3 H-GABA-lipids. The apparent dissociation constants (K/sub d/) for 3 H-GABA-lipids or 14 C-glutamate-lipids interactions inorganic medium were in the millimolar range and maximal charge between 3 and 7 moles of GABA or glutamate by mole of lipid. Amino acids such as glutamic acid, β-alanine and glycine displaced 3 H-GABA with the same potency as GABA itself; thus these results show that the interaction lacks pharmacological specificity. To detect this interaction lipid concentrations higher than 2 μM were required and in the partition system 3 H-GABA and lipid phosphorus were both concentrated at the interface. Therefore, lipids tested with a biphasic partition system do not fulfill the classical criteria for a neurotransmitter receptor at least not for GABA and glutamate. 15 references, 1 figure, 3 tables

  8. Using the printed medium to disseminate information about ...

    African Journals Online (AJOL)

    Using the printed medium to disseminate information about psychiatric disorders: original article. ... Key Words: Health information, Information material, Communication / dissemination of health information, Text-focused research, Usability testing, Message design, Printed medium, Mental health, Schizophrenia

  9. Electromagnetic radiation in a medium with a velocity gradient

    Science.gov (United States)

    Gladyshev, V. O.; Tereshin, A. A.; Bazleva, D. D.

    2016-04-01

    A relativistic expression has been obtained for the curvature of trajectory of the wave vector of an electromagnetic wave in a moving optically transparent medium. It has been shown that the curvature of the trajectory and angular deviation of rays appear in a homogeneous isotropic medium if the gradient of the velocity field in the medium is nonzero. The bending of the trajectory in the medium with the velocity gradient is a firstorder effect in the ratio u/ c.

  10. Effect of potassium simplex optimization medium (KSOM) and ...

    African Journals Online (AJOL)

    In this study, we produced cloned transgenic dairy goat based on dairy goat ear skin fibroblast as donor cells for nuclear transfer (NT), which were modified by ... culture medium, potassium simplex optimization medium (KSOM) and tissue culture medium (TCM 199), or different classification of NT embryos (48 h after fusion).

  11. Lime-amended growing medium causes seedling growth distortions

    Science.gov (United States)

    R. Kasten Dumroese; Gale Thompson; David L. Wenny

    1990-01-01

    Although a commercial growing medium with incorporated agricultural lime had been successfully used for years, it caused growth distortion of coniferous and deciduous seedlings during 1988. Seedlings grown in the amended medium were stunted and chlorotic, often with disfigured needles and multiple tops. Seedlings grown in the same medium without incorporated lime grew...

  12. Medium optimization for protopectinase production by batch culture of

    African Journals Online (AJOL)

    Medium optimization for protopectinase production by batch culture of. C Fan, Z Liu, L Yao. Abstract. Optimization of medium compositions for protopectinase production by Aspergillus terreus in submerged culture was carried out. The medium components having significant effect on protopectinase production were reported ...

  13. 7 CFR 51.2751 - U.S. Medium Virginia.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. Medium Virginia. 51.2751 Section 51.2751... STANDARDS) United States Standards for Shelled Virginia Type Peanuts Grades § 51.2751 U.S. Medium Virginia. “U.S. Medium Virginia” consists of shelled Virginia type peanut kernels of similar varietal...

  14. Economic Efficiency of small and Medium Scale Cassava ...

    African Journals Online (AJOL)

    ... medium scale enterprises. Small and medium scale cassava processor should therefore focus more on ways of accessing credit while government should ensure more extension visits to the processors. Key words; Economic Efficiency, Small and Medium Enterprise, Cassava Processing Enterprise, Nigeria, Agribusiness ...

  15. 21 CFR 133.103 - Asiago medium cheese.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Asiago medium cheese. 133.103 Section 133.103 Food... HUMAN CONSUMPTION CHEESES AND RELATED CHEESE PRODUCTS Requirements for Specific Standardized Cheese and Related Products § 133.103 Asiago medium cheese. Asiago medium cheese conforms to the definition and...

  16. 30 CFR 75.703-2 - Approved grounding mediums.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved grounding mediums. 75.703-2 Section 75... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Grounding § 75.703-2 Approved grounding mediums. For purposes of grounding offtrack direct-current machines, the following grounding mediums are...

  17. High frequency plant regeneration from mature seedderived callus ...

    African Journals Online (AJOL)

    In the present study, we have developed a high-frequency plant regeneration system for Italian ryegrass via callus culture using mature seeds as explants. Optimal embryogenic callus induction was found to occur in MS medium containing 5 mg l-1 2,4-D, 0.5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein hydrolysate, 30 g ...

  18. Resonance frequency analysis

    Directory of Open Access Journals (Sweden)

    Rajiv K Gupta

    2011-01-01

    Full Text Available Initial stability at the placement and development of osseointegration are two major issues for implant survival. Implant stability is a mechanical phenomenon which is related to the local bone quality and quantity, type of implant, and placement technique used. The application of a simple, clinically applicable, non-invasive test to assess implant stability and osseointegration is considered highly desirable. Resonance frequency analysis (RFA is one of such techniques which is most frequently used now days. The aim of this paper was to review and analyze critically the current available literature in the field of RFA, and to also discuss based on scientific evidence, the prognostic value of RFA to detect implants at risk of failure. A search was made using the PubMed database to find all the literature published on "Resonance frequency analysis for implant stability" till date. Articles discussed in vivo or in vitro studies comparing RFA with other methods of implant stability measurement and articles discussing its reliability were thoroughly reviewed and discussed. A limited number of clinical reports were found. Various studies have demonstrated the feasibility and predictability of the technique. However, most of these articles are based on retrospective data or uncontrolled cases. Randomized, prospective, parallel-armed longitudinal human trials are based on short-term results and long-term follow up are still scarce in this field. Nonetheless, from available literature, it may be concluded that RFA technique evaluates implant stability as a function of stiffness of the implant bone interface and is influenced by factors such as bone type, exposed implant height above the alveolar crest. Resonance frequency analysis could serve as a non-invasive diagnostic tool for detecting the implant stability of dental implants during the healing stages and in subsequent routine follow up care after treatment. Future studies, preferably randomized

  19. Effective medium theory for elastic matrix composites containing dispersed particulates

    International Nuclear Information System (INIS)

    Jhon, M.S.; Metz, R.J.; Freed, K.F.

    1988-01-01

    We describe a new, effective medium theory to study the wave propagation and mechanical properties of a composite system with dispersed particulates. One main emphasis here is in formulating the theory and in analyzing the structure of the contribution of the fillers to the elastic response. By constructing the elastic propagator (whose fluid mechanical counterpart is known as the Oseen tensor), we show that an analogy between the theoretical description of the particulate system and of suspension rheology exists when the former corresponds to a high-rigidity solid matrix (or, analogously, when the Poisson ratio is close to 1/2) in steady state. The effective Lame constants for this case are derived by combining this analogy with the theory developed by Freed and Muthukumar for the rheology of a suspension of spheres. The analogy is also useful in our new prediction of the phenomenon of elastic screening, the possible existence of a cutoff frequency below which elastic waves cannot propagate in the filler system

  20. A Transformerless Medium Voltage Multiphase Motor Drive System

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2016-04-01

    Full Text Available A multiphase motor has several major advantages, such as high reliability, fault tolerance, and high power density. It is a critical issue to develop a reliable and efficient multiphase motor drive system. In this paper, a transformerless voltage source converter-based drive system for a medium-voltage (MV multiphase motor is proposed. This drive converter employs cascaded H-bridge rectifiers loaded by H-bridge inverters as the interface between the grid and multiphase motor. The cascaded H-bridge rectifier technique makes the drive system able to be directly connected to the MV grid without the phase-shifting transformer because it can offset the voltage level gap between the MV grid and the semiconductor devices, provide near-sinusoidal AC terminal voltages without filters, and draw sinusoidal line current from the grid. Based on a digital signal processor (DSP, a complete improved Phase Disposition Pulse Width Modulation (PD-PWM method is developed to ensure the individual DC-link capacitor voltage balancing for enhancing the controllability and limiting the voltage and power stress on the H-bridge cells. A downscaled prototype is designed and developed based on a nine-phase motor. The experimental results verify the excellent performances of the proposed drive system and control strategy in steady-state and variant-frequency startup operations.

  1. Radio frequency pulse compression

    International Nuclear Information System (INIS)

    Farkas, Z.D.

    1988-12-01

    High gradients require peak powers. One possible way to generate high peak powers is to generate a relatively long pulse at a relatively low power and compress it into a shorter pulse with higher peak power. It is possible to compress before dc to rf conversion as is done for the relativistic klystron or after dc to rf conversion as is done with SLED. In this note only radio frequency pulse compression (RFPC) is considered. Three methods of RFPC will be discussed: SLED, BEC, and REC. 3 refs., 8 figs., 1 tab

  2. Low-frequency ac electroporation shows strong frequency dependence and yields comparable transfection results to dc electroporation.

    Science.gov (United States)

    Zhan, Yihong; Cao, Zhenning; Bao, Ning; Li, Jianbo; Wang, Jun; Geng, Tao; Lin, Hao; Lu, Chang

    2012-06-28

    Conventional electroporation has been conducted by employing short direct current (dc) pulses for delivery of macromolecules such as DNA into cells. The use of alternating current (ac) field for electroporation has mostly been explored in the frequency range of 10kHz-1MHz. Based on Schwan equation, it was thought that with low ac frequencies (10Hz-10kHz), the transmembrane potential does not vary with the frequency. In this report, we utilized a flow-through electroporation technique that employed continuous 10Hz-10kHz ac field (based on either sine waves or square waves) for electroporation of cells with defined duration and intensity. Our results reveal that electropermeabilization becomes weaker with increased frequency in this range. In contrast, transfection efficiency with DNA reaches its maximum at medium frequencies (100-1000Hz) in the range. We postulate that the relationship between the transfection efficiency and the ac frequency is determined by combined effects from electrophoretic movement of DNA in the ac field, dependence of the DNA/membrane interaction on the ac frequency, and variation of transfection under different electropermeabilization intensities. The fact that ac electroporation in this frequency range yields high efficiency for transfection (up to ~71% for Chinese hamster ovary cells) and permeabilization suggests its potential for gene delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Transitioning from Maori-Medium to English-Medium Education: Emerging Findings of a Pilot Study

    Science.gov (United States)

    Hill, Richard

    2016-01-01

    Maori-bilingual education in New Zealand has come a long way towards injecting life into the Maori language. However, only a small number of families commit to bilingual education for the long term. This paper discusses why Maori parents either turn away from Maori-bilingual education or prematurely transition to English-medium schools. It then…

  4. [Spin dependent phenomena in medium energy physics

    International Nuclear Information System (INIS)

    Souder, P.A.

    1992-11-01

    The Syracuse University Medium Energy Physics Group was actively engaged in several research projects. A laser was used to polarize muonic atoms with the goal of measuring fundamental spin-dependent parameters in the reaction μ - + 3 He → 3 H + ν. Time-averaged polarizations of 26.8±2.3% were achieved for the muon in muonic 3 He. The new approach uses atomic spin-dependent reactions between laser polarized Rb vapor and muonic helium. To exploit these high polarizations in a muon capture experiment an ion chamber which will detect the recoil tritons and also serve as a polarizing cell. Final data-taking will begin for an experiment to measure the spin-dependent structure functions of the neutron. A 288-element hodoscope system which features good timing and precise mechanical tolerances was constructed and evaluated

  5. Light Vector Mesons in the Nuclear Medium

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen

    2008-07-01

    The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff

  6. Cosmic rays and the interstellar medium

    International Nuclear Information System (INIS)

    Wolfendale, A.W.

    1986-01-01

    It is inevitable that there is a close connection between cosmic rays and the ISM insofar as the propagation of cosmic rays is conditioned by the magnetic field in the ISM and the cosmic rays interact with the gas (and photon fluxes) in this medium. This paper deals with both topics. Propagation effects manifest themselves as an anisotropy in arrival directions and a review is given of anisotropy measurements and their interpretation. The status of studies of cosmic ray interactions is examined whit particular reference to the information about the ISM itself which comes from observations of the flux of secondary γ-rays produced by cosmic ray interactions with gas, the situation regarding molecular as in the Inner Galaxy being of particular concern

  7. Fluid flow through anisotropic porous medium

    International Nuclear Information System (INIS)

    Telles, A.S.; Massarani, G.

    1975-01-01

    Darcy's equation represents a simplified form of the equation of motion for the fluid flowing through a porous medium. The simplifications concern the elimination of the acceleration, the divergence of the extra stress terms, and the assumption of existence of a linear form in the velocity for the resistive force the fluid exerts upon the solid. This hypothesis may not be valid for all anisotropic media. In some instances, measurements of directional resistivity suggest existence of the resistivity tensor, leaving entirely open the question of symmetry. In connection with this important question, an experimental scheme for the determination of the antisymmetric part of this tensor is suggested. The conclusion is that material symmetries is the only macroscopic concept that imposes restrictions on the form of the resistivity and extra stress tensors [pt

  8. "Resolving" the Problems of the Circumgalactic Medium

    Science.gov (United States)

    Hummels, Cameron

    2018-01-01

    Galactic gas accretion drives the formation and evolution of every galaxy. The circumgalactic medium, the tenuous gas surrounding a galaxy, acts as a direct probe of star formation, stellar feedback, and gas accretion, all responsible for a galaxy's fate. To date, attempts to model the multiphase CGM have failed to adequately match observations, leaving many unanswered questions regarding its origin, distribution, and kinematics. In this talk I will present synthetic observations of the CGM from the FIRE simulations and the TempestCGM simulations, two sets of state-of-the-art cosmological hydrodynamic zoom-in simulations with extremely high spatial resolution. For the first time, these models are able to reproduce many of the CGM observational samples (e.g. COS-Halos), and they indicate that the size of the physical structures of the CGM are smaller than previously simulated (< 1 kpc).

  9. Polarization of submillimetre lines from interstellar medium

    Science.gov (United States)

    Zhang, Heshou; Yan, Huirong

    2018-04-01

    Magnetic fields play important roles in many astrophysical processes. However, there is no universal diagnostic for the magnetic fields in the interstellar medium (ISM) and each magnetic tracer has its limitation. Any new detection method is thus valuable. Theoretical studies have shown that submillimetre fine-structure lines are polarized due to atomic alignment by ultraviolet photon-excitation, which opens up a new avenue to probe interstellar magnetic fields. We will, for the first time, perform synthetic observations on the simulated three-dimensional ISM to demonstrate the measurability of the polarization of submillimetre atomic lines. The maximum polarization for different absorption and emission lines expected from various sources, including star-forming regions are provided. Our results demonstrate that the polarization of submillimetre atomic lines is a powerful magnetic tracer and add great value to the observational studies of the submilimetre astronomy.

  10. Abundances in the diffuse interstellar medium

    International Nuclear Information System (INIS)

    Harris, A.W.

    1988-04-01

    The wealth of interstellar absorption line data obtained with the Copernicus and IUE satellites has opened up a new era in studies of the interstellar gas. It is now well established that certain elements, generally those with high condensation temperatures, are substantially under-abundant in the gas-phase relative to total solar or cosmic abundances. This depletion of elements is due to the existence of solid material in the form of dust grains in the interstellar medium. Surprisingly, however, recent surveys indicate that even volatile elements such as Zn and S are significantly depleted in many sight lines. Developments in this field which have been made possible by the large base of UV interstellar absorption line data built up over recent years are reviewed and the implications of the results for our understanding of the physical processes governing depletion are discussed. (author)

  11. Thermal instability in the interstellar medium

    Directory of Open Access Journals (Sweden)

    J. Ghanbari

    2000-06-01

    Full Text Available   This study demonstrates how thermal structures in the interstellar medium can emerge as a result of thermal instability. For a two-dimensional case, the steady state thermal structures was investigeted and it was shown that a large class of solutions exist. For a one –dimensional case the conductivity was found to be negligible. The effects of to cal cooling on the thermal instability were explored in some depth. In this case analytical results for time-dependent cooling function were presented, too. We studied nonlinear wave phenomena in thermal fluid systems, with a particular emphasis on presenting analytical results. When conductivity is proportional to temperature, the beliavior of thermal waves is soliton like. For slow thermal waves, approximate analytical results were presented. Extensions of this work are discussed briefly, together with possible astrophysical applications.

  12. Medium Duty Electric Vehicle Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, Robin J. D. [Smith Electric Vehicles Corporation, Kansas City, MO (United States)

    2015-05-31

    The Smith Electric Vehicle Demonstration Project (SDP) was integral to the Smith business plan to establish a manufacturing base in the United States (US) and produce a portfolio of All Electric Vehicles (AEV’s) for the medium duty commercial truck market. Smith focused on the commercial depot based logistics market, as it represented the market that was most ready for the early adoption of AEV technology. The SDP enabled Smith to accelerate its introduction of vehicles and increase the size of its US supply chain to support early market adoption of AEV’s that were cost competitive, fully met the needs of a diverse set of end users and were compliant with Federal safety and emissions requirements. The SDP accelerated the development and production of various electric drive vehicle systems to substantially reduce petroleum consumption, reduce vehicular emissions of greenhouse gases (GHG), and increase US jobs.

  13. Managing Safety in Small and Medium Enterprises

    DEFF Research Database (Denmark)

    Stephen, legg; Olsen, Kirsten Bendix; Ian S., laird

    2015-01-01

    This paper presents a conceptual model for increasing acceptable working environments for SMEs. It also acts as an editorial for the special issue of Safety Science on ‘Managing safety in small and medium enterprises (SMEs)’. It describes how seven of the ten papers in the special issue originate...... on safety in SMEs, showing how most current policy and legislation on occupational health and safety (OSH) and the work environment is based on large enterprises and that there is a relative paucity of research on OSH in SMEs. In a summary of current knowledge, it is argued that modern OHS legislation...... and interventions to help improve Work environments need to increasingly take account of the specific characteristics of SMEs. The conceptual model for increasing acceptable working environments for SMEs takes its onset in a legislative standard that is built into intervention programmes and includes three...

  14. A medium resolution fingerprint matching system

    Directory of Open Access Journals (Sweden)

    Ayman Mohammad Bahaa-Eldin

    2013-09-01

    Full Text Available In this paper, a novel minutiae based fingerprint matching system is proposed. The system is suitable for medium resolution fingerprint images obtained by low cost commercial sensors. The paper presents a new thinning algorithm, a new features extraction and representation, and a novel feature distance matching algorithm. The proposed system is rotation and translation invariant and is suitable for complete or partial fingerprint matching. The proposed algorithms are optimized to be executed on low resource environments both in CPU power and memory space. The system was evaluated using a standard fingerprint dataset and good performance and accuracy were achieved under certain image quality requirements. In addition, the proposed system was compared favorably to that of the state of the art systems.

  15. Water based fluidic radio frequency metamaterials

    Science.gov (United States)

    Cai, Xiaobing; Zhao, Shaolin; Hu, Mingjun; Xiao, Junfeng; Zhang, Naibo; Yang, Jun

    2017-11-01

    Electromagnetic metamaterials offer great flexibility for wave manipulation and enable exceptional functionality design, ranging from negative refraction, anomalous reflection, super-resolution imaging, transformation optics to cloaking, etc. However, demonstration of metamaterials with unprecedented functionalities is still challenging and costly due to the structural complexity or special material properties. Here, we demonstrate for the first time the versatile fluidic radio frequency metamaterials with negative refraction using a water-embedded and metal-coated 3D architecture. Effective medium analysis confirms that metallic frames create an evanescent environment while simultaneously water cylinders produce negative permeability under Mie resonance. The water-metal coupled 3D architectures and the accessory devices for measurement are fabricated by 3D printing with post electroless deposition. Our study also reveals the great potential of fluidic metamaterials and versatility of the 3D printing process in rapid prototyping of customized metamaterials.

  16. Coupleurs fibres - metasurfaces aux frequences THz

    Science.gov (United States)

    Girard, Martin

    Metamaterials are a class of arficial materials where the electromagnetic properties can be tailored during the design process. Currently demonstrated properties are varied, ranging from frequency filters to enhancement of quentum effects such as photon spin Hall effect. While these materials are mastered from a theoretical point of view, their fabrication is much more complicated. It is generally accepted that metamaterial elements must be under the effective medium limit (Lambda 3D periodical system becomes much more complicated for small elements. For this reason, metamaterials are usually printed in 2D, on a surface, which are called metasurfaces. Generally, these are produced for the THz frequencies (˜ 1012 Hz) or lower to have a large wavelength and thus easy fabrication. Working at THz frequencies also carries additional problems. Absorption in traditional optical mediums is typically large (for exemple, BK7 glass has losses of 20 dB / cm) and powers supplied by THz sources are generally weak ( 100 muW for a THz-TDS standard source). Metasurfaces can thus play an important role by replacing traditional mediums. Moreover, we can use the resonant properties of metamaterials to produce sensors and other devices. Currently, the metasurfaces are used in conjuction with a free-space beam instead of a typical waveguide, which may be problematic when implementing devices. A simple solution to this problem is to use the metamaterial as a standard coupler by placing a waveguide above the metasurface. As stated before, we generally consider metasurfaces as effective mediums, where the permittivity is insensitive to the angle of the incident beam. However, a large amount of publications on this subject shows that this is not respected. This can have a huge impact on properties of a coupler based on such a material. First, modelisation is not a simple 2D mode calculation with a simple expression for permittivity. Second, contra-directional coupling becomes permitted due

  17. Magnetic Fields in the Interstellar Medium

    Science.gov (United States)

    Clark, Susan

    2017-01-01

    The Milky Way is magnetized. Invisible magnetic fields thread the Galaxy on all scales and play a vital but still poorly understood role in regulating flows of gas in the interstellar medium and the formation of stars. I will present highlights from my thesis work on magnetic fields in the diffuse interstellar gas and in accretion disks. At high Galactic latitudes, diffuse neutral hydrogen is organized into an intricate network of slender linear features. I will show that these neutral hydrogen “fibers” are extremely well aligned with the ambient magnetic field as traced by both starlight polarization (Clark et al. 2014) and Planck 353 GHz polarized dust emission (Clark et al. 2015). The structure of the neutral interstellar medium is more tightly coupled to the magnetic field than previously known. Because the orientation of neutral hydrogen is an independent predictor of the local dust polarization angle, our work provides a new tool in the search for inflationary gravitational wave B-mode polarization in the cosmic microwave background, which is currently limited by dust foreground contamination. Magnetic fields also drive accretion in astrophysical disks via the magnetorotational instability (MRI). I analytically derive the behavior of this instability in the weakly nonlinear regime and show that the saturated state of the instability depends on the geometry of the background magnetic field. The analytical model describes the behavior of the MRI in a Taylor-Couette flow, a set-up used by experimentalists in the ongoing quest to observe MRI in the laboratory (Clark & Oishi 2016a, 2016b).

  18. Barometric Pumping of a Fractured Porous Medium

    Science.gov (United States)

    Adler, P. M.; Mourzenko, V.; Thovert, J. F.; Pili, E.; Guillon, S.

    2014-12-01

    Fluctuations in the ambient atmospheric pressure result in motion of air in porous fractured media. This mechanism, known as barometric pumping, efficiently transports gaseous species through the vadose zone to the atmosphere. This is of interest in fields, such as transport of trace gases from soil to atmosphere, remediation of contaminated sites, radon in buildings, leakage from carbon sequestration sites and detection of nuclear explosions. The fractures are modeled as polygonal plane surfaces with a given transmissivity embedded in a permeable matrix. The slightly compressible fluid obeys Darcy's law in these two media with exchanges between them. The solute obeys convection-diffusion equations in both media again with exchanges. The fractures and the porous medium are meshed by triangles and tetrahedra, respectively. The equations are discretized by the finite volume method. A Flux Limiting Scheme diminishes numerical dispersion ; the solute transfer between the fractures and the porous medium is precisely evaluated. The resulting equations are solved by conjugate gradient algorithms. This model is applied to the Roselend Natural Laboratory. At a 55 m depth, a sealed cavity allows for gas release experiments across fractured porous rocks in the unsaturated zone. The fractures are hexagons with a radius of 5m; their density is larger than 2.4 10-3 m-3; the aperture is about 0.5 mm. The pressure fluctuations are sinusoidal, of amplitude 0.01 bar and period 1 week. The solute concentration is equal to 1 at the bottom. Systematic results will be presented. First, the precision of the calculations is assessed. Second, the pressure and solute concentration fields are displayed and discussed. Third, the influence of the major parameters (fracture density, aperture, porosity, diffusion coefficient,…) is illustrated and discussed. These results are discussed in terms of the amplification of solute transfer to the ground surface by the pressure fluctuations.

  19. STUDIES REGARDING CULTURE MEDIUM INFLUENCE ON IN VITRO REGENERATION FROM WHEAT IMATURE EMBRYOS

    Directory of Open Access Journals (Sweden)

    M. DANCI

    2008-05-01

    Full Text Available Surnamed „embryos’ saving method”, embryos culture is an in vitro technique used for over half of the century for saving the distant hybridization products, that would have degenerate in other conditions. Immature embryos culture is used for initiation of in vitro cultures imposed by the impossibility of using other explants for some of the plant species. Wheat is one of the crops that immature embryos culture technique is suitable for. This methods principle is based on aseptic embryos excision and their inoculation to an adequate culture medium. In vitro culture results depend in a greater manner of the basic culture medium and the hormonal balance used. Immature embryos isolated from two Romanian wheat cultivars – Dropia and Lovrin 41 – were inoculated for callus production on two types of basic media added with 2,4 D. The selected calluses were transferred on MS basic medium and several parameters were registered. Both cultivars emphasized a good callusing capacity, in a different percentage depending on the culture media used, such as 71,09 – 94,45%.. big differences between the cultivars regarding embriogenic callus frequency, shooting callus frequency and regenerated plants percentage were registered.

  20. Behavioral estimates of human frequency selectivity at low frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado

    on physical sound measurements. In this PhD thesis a detailed description of frequency selectivity at low frequencies is given. Different experiments have been performed to determine the properties of human auditory filters. Besides, loudness perception of low-frequency sinusoidal signals has been evaluated...

  1. Scattering of elastic waves on fractures randomly distributed in a three-dimensional medium

    Science.gov (United States)

    Strizhkov, S. A.; Ponyatovskaya, V. I.

    1985-02-01

    The purpose of this work is to determine the variation in basic characteristics of the wave field formed in a jointed medium, such as the intensity of fluctuations of amplitude, correlation radius, scattering coefficient and frequency composition of waves, as functions of jointing parameters. Fractures are simulated by flat plates randomly distributed and chaotically oriented in a three-dimensional medium. Experiments were performed using an alabaster model, a rectangular block measuring 50 x 50 x 120 mm. The plates were introduced into liquid alabaster which was then agitated. Models made in this way contain randomly distributed and chaotically oriented fractures. The influence of these fractures appears as fluctuations in the wave field formed in the medium. The data obtained in experimental studies showed that the dimensions of heterogeneities determined by waves in the jointed medium and the dimensions of the fractures themselves coincide only if the distance between fractures is rather great. If the distance between fractures is less than the wavelength, the dimensions of the heterogeneities located by the wave depend on wavelength.

  2. Spiral waves in driven dusty plasma medium: Generalized hydrodynamic fluid description

    Science.gov (United States)

    Kumar, Sandeep; Patel, Bhavesh; Das, Amita

    2018-04-01

    Spiral waves are observed in many natural phenomena. They have been extensively represented by the mathematical FitzHugh-Nagumo model [Barkley et al., Phys. Rev. A 42, 2489 (1990)] of excitable media. Also, in incompressible fluid simulations, the excitation of thermal spiral waves has been reported by Li et al. [Phys. of Fluids 22, 011701 (2010)]. In the present paper, the spatiotemporal development of spiral waves in the context of weak and strong coupling limits has been shown. While the weakly coupled medium has been represented by a simple fluid description, for strong coupling, a generalized visco-elastic fluid description has been employed. The medium has been driven by an external force in the form of a rotating electric field. It is shown that when the amplitude of force is small, the density perturbations in the medium are also small. In this case, the excitations do not develop as a spiral wave. Only when the amplitude of force is high so as to drive the density perturbations to nonlinear amplitudes does the spiral density wave formation occurs. The role of the forcing frequency and the effect of strong coupling and the sound velocity of medium in the formation and evolution of spiral waves have been investigated in detail.

  3. Exact solution for thermo-mechanical vibration of orthotropic mono-layer graphene sheet embedded in an elastic medium

    Directory of Open Access Journals (Sweden)

    M. Mohammadi

    Full Text Available In this paper, the effect of the temperature change on the vibration frequency of mono-layer graphene sheet embedded in an elastic medium are studied. Using the nonlocal elasticity theory, the governing equations are derived for single-layered graphene sheets. Using Levy and Navier solutions, analytical frequency equations for single-layered graphene sheets are obtained. Using Levy solution, the frequency equation and mode shapes of orthotropic rectangular nanoplate are considered for three cases of boundary conditions. The obtained results are subsequently compared with valid result reported in the literature. The effects of the small scale, temperature change, different boundary conditions, Winkler and Pasternak foundations, material properties and aspect ratios on natural frequencies are investigated. It has been shown that the non-dimensional frequency decreases with increasing temperature change. The present analysis results can be used for the design of the next generation of nanodevices that make use of the thermal vibration properties of the nanoplates.

  4. Masked priming by misspellings: Word frequency moderates the effects of SOA and prime-target similarity.

    Science.gov (United States)

    Burt, Jennifer S

    2016-02-01

    University students made lexical decisions to eight- or nine-letter words preceded by masked primes that were the target, an unrelated word, or a typical misspelling of the target. At a stimulus onset asynchrony (SOA) of 47 ms, primes that were misspellings of the target produced a priming benefit for low-, medium-, and high-frequency words, even when the misspelled primes were changed to differ phonologically from their targets. At a longer SOA of 80 ms, misspelled primes facilitated lexical decisions only to medium- and low-frequency targets, and a phonological change attenuated the benefit for medium-frequency targets. The results indicate that orthographic similarity can be preserved over changes in letter position and word length, and that the priming effect of misspelled words at the shorter SOA is orthographically based. Orthographic-priming effects depend on the quality of the orthographic learning of the target word.

  5. Frequency agile solar radiotelescope

    Science.gov (United States)

    Bastian, Tim S.

    2003-02-01

    The Frequency Agile Solar Radiotelescope (FASR) is a solar-dedicated, ground based, interferometric array optimized to perform broadband imaging spectroscopy from ~ 0.1-30+ GHz. It will do so with the angular, spectral, and temporal resolution required to exploit radio emission from the Sun as a diagnostic of the wide variety of astrophysical processes that occur there. FASR represents a major advance over existing radioheliographs, and is expected to remain the world's premier solar radio instrument for two decades or more after completion. FASR will be a versatile and powerful instrument, providing unique data to a broad users community. Solar, solar-terrestrial, and space physicists will exploit FASR to attack a broad science program, including problems of fundamental interest: coronal magnetography, solar flares and particle acceleration, drivers of space weather, and the thermal structure and dynamics of the solar atmosphere. A design study and implementation planning are underway. Recent progress is reviewed here.

  6. Frequency scanning microstrip antennas

    DEFF Research Database (Denmark)

    Danielsen, Magnus; Jørgensen, Rolf

    1979-01-01

    The principles of using radiating microstrip resonators as elements in a frequency scanning antenna array are described. The resonators are cascade-coupled. This gives a scan of the main lobe due to the phase-shift in the resonator in addition to that created by the transmission line phase......-shift. Experimental results inX-band, in good agreement with the theory, show that it is possible to scan the main lobe an angle ofpm30degby a variation of the frequencypm300MHz, and where the 3 dB beamwidth is less than10deg. The directivity was 14.7 dB, while the gain was 8.1 dB. The efficiency might be improved...

  7. High frequency nanotube oscillator

    Science.gov (United States)

    Peng, Haibing [Houston, TX; Zettl, Alexander K [Kensington, TX

    2012-02-21

    A tunable nanostructure such as a nanotube is used to make an electromechanical oscillator. The mechanically oscillating nanotube can be provided with inertial clamps in the form of metal beads. The metal beads serve to clamp the nanotube so that the fundamental resonance frequency is in the microwave range, i.e., greater than at least 1 GHz, and up to 4 GHz and beyond. An electric current can be run through the nanotube to cause the metal beads to move along the nanotube and changing the length of the intervening nanotube segments. The oscillator can operate at ambient temperature and in air without significant loss of resonance quality. The nanotube is can be fabricated in a semiconductor style process and the device can be provided with source, drain, and gate electrodes, which may be connected to appropriate circuitry for driving and measuring the oscillation. Novel driving and measuring circuits are also disclosed.

  8. High Frequency Oscillatory Ventilation

    Directory of Open Access Journals (Sweden)

    AC Bryan

    1996-01-01

    Full Text Available High frequency oscillatory (HFO ventilation using low tidal volume and peak airway pressures is extremely efficient at eliminating carbon dioxide and raising pH in the newborn infant with acute respiratory failure. Improvement in oxygenation requires a strategy of sustained or repetitive inflations to 25 to 30 cm H2O in order to place the lung on the deflation limb of the pressure-volume curve. This strategy has also been shown to decrease the amount of secondary lung injury in animal models. Experience of the use of HFO ventilation as a rescue therapy as well as several published controlled trials have shown improved outcomes and a decrease in the use of extracorporeal membrane oxygenation when it has been used in newborns.

  9. Frequency doubling crystals

    Science.gov (United States)

    Wang, Francis; Velsko, Stephan P.

    1989-01-01

    A systematic approach to the production of frequency conversion crystals is described in which a chiral molecule has attached to it a "harmonic generating unit" which contributes to the noncentrosymmetry of the molecule. Certain preferred embodiments of such harmonic generating units include carboxylate, guanadyly and imidazolyl units. Certain preferred crystals include L-arginine fluoride, deuterated L-arginine fluoride, L-arginine chloride monohydrate, L-arginine acetate, dithallium tartrate, ammonium N-acetyl valine, N-acetyl tyrosine and N-acetyl hydroxyproline. Chemical modifications of the chiral molecule, such as deuteration, halogenation and controlled counterion substitution are available to adapt the dispersive properties of a crystal in a particular wavelength region.

  10. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  11. Robust power system frequency control

    CERN Document Server

    Bevrani, Hassan

    2014-01-01

    This updated edition of the industry standard reference on power system frequency control provides practical, systematic and flexible algorithms for regulating load frequency, offering new solutions to the technical challenges introduced by the escalating role of distributed generation and renewable energy sources in smart electric grids. The author emphasizes the physical constraints and practical engineering issues related to frequency in a deregulated environment, while fostering a conceptual understanding of frequency regulation and robust control techniques. The resulting control strategi

  12. iBook – a New Medium?

    Directory of Open Access Journals (Sweden)

    Benjamin Štular

    2013-09-01

    Full Text Available EXTENDED ABSTRACT:On January 19th 2012 Apple launched iBooks®2 for iPad® - a new application for downloading digital content to the iPad - and the new software (iBooks Author® which allows creating and publishing digital content using the .iba digital format and all-new iTunes® application offering access to a variety of digitised educational content. Our aim was to test the attractiveness of the new Apple releases and the effect of a relatively easy access to the world market of digital content on the promotion of Slovenian cultural heritage. We added three books to the iTunes digital collection which might be of interest to the general public: a re-edition of a scientific monograph by Andrej Pleterski: Mythical Reality of the Carintian Dukes' Stones (Mitska stvarnost knežjega kamna in Slovenian and German version and a non-fiction iBook by Benjamin Štular: Ljubljana in the Middle Ages. Archaeological Research (Srednjeveška Ljubljana. Arheološke raziskave. The digital version of the Andrej Pleterski's book was chosen for the actuality of the topic in Slovenia and Austria. People and politicians in Carinthia were annoyed by the book contents as it was published by the Regional Museum in Klagenfurt in December 2011. While the science in this book is sound it has been abused to meet the current needs of some of the Carinthian politicians. The incident was polemically reflected in the main Slovenian newspapers, too. The non-fiction iBook was selected because of the attractiveness of the theme, besides a lot of multimedia content had already been created and could be easily published to Apple's iBookstore. All three iBooks were posted to iTunes® less than three weeks after the release of the iBooks Author application to create digital content. We wish to present our experience with the applicability of the new medium, users' feedback and access statistics. Guidelines for Apple licenses are presented. The applicability of the new medium and

  13. Hard QCD processes in the nuclear medium

    Science.gov (United States)

    Freese, Adam

    The environment inside the atomic nucleus is one of the most fascinating arenas for the study of quantum chromodynamics (QCD). The strongly-interacting nature of the nuclear medium a?ects the nature of both QCD processes and the quark-gluon structure of hadrons, allowing several unique aspects of the strong nuclear force to be investigated in reactions involving nuclear targets. The research presented in this dissertation explores two aspects of nuclear QCD: firstly, the partonic structure of the nucleus itself; and secondly, the use of the nucleus as a micro-laboratory in which QCD processes can be studied. The partonic structure of the nucleus is calculated in this work by deriving and utilizing a convolution formula. The hadronic structure of the nucleus and the quark-gluon structure of its constituent nucleons are taken together to determine the nuclear partonic structure. Light cone descriptions of short range correlations, in terms of both hadronic and partonic structure, are derived and taken into account. Medium modifications of the bound nucleons are accounted for using the color screening model, and QCD evolution is used to connect nuclear partonic structure at vastly di?erent energy scales. The formalism developed for calculating nuclear partonic structure is applied to inclusive dijet production from proton-nucleus collisions at LHC kinematics, and novel predictions are calculated and presented for the dijet cross section. The nucleus is investigated as a micro-laboratory in vector meson photoproduction reactions. In particular, the deuteron is studied in the break-up reaction gammad → Vpn, for both the φ(1020) and J/v vector mesons. The generalized eikonal approximation is utilized, allowing unambiguous separation of the impulse approximation and final state interactions (FSIs). Two peaks or valleys are seen in the angular distribution of the reaction cross section, each of which is due to an FSI between either the proton and neutron, or the

  14. Frequency effects in compound production

    NARCIS (Netherlands)

    Bien, H.; Levelt, W.J.M.; Baayen, R.H.

    2005-01-01

    Four experiments investigated the role of frequency information in compound production by independently varying the frequencies of the first and second constituent as well as the frequency of the compound itself. Pairs of Dutch noun-noun compounds were selected such that there was a maximal contrast

  15. Quantum optical effective-medium theory for loss-compensated metamaterials

    DEFF Research Database (Denmark)

    Amooghorban, Ehsan; Mortensen, N. Asger; Wubs, Martijn

    2013-01-01

    A central aim in metamaterial research is to engineer subwavelength unit cells that give rise to desired effective-medium properties and parameters, such as a negative refractive index. Ideally one can disregard the details of the unit cell and employ the effective description instead. A popular...... strategy to compensate for the inevitable losses in metallic components of metamaterials is to add optical gain material. Here we study the quantum optics of such loss-compensated metamaterials at frequencies for which effective parameters can be unambiguously determined. We demonstrate that the usual...... effective parameters are insufficient to describe the propagation of quantum states of light. Furthermore, we propose a quantum optical effective-medium theory instead and show that it correctly predicts the properties of the light emerging from loss-compensated metamaterials. © 2013 American Physical...

  16. An Analysis of Medium Loss of Coolant Sequence for the Severe Accident Analysis DB

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Yong; Song, Yong Mann

    2007-12-15

    This report contains analysis methodologies and calculation results of medium loss of Coolant sequences for the severe accident analysis database system. The Korean standard nuclear power plant has been selected as a reference plant. Based on the probabilistic safety analysis of the corresponding plant, 10 accident scenarios, which was predicted to have more than 10{sup -10} /ry occurrence frequency, have been analyzed as base cases for the medium loss of Coolant sequence database. The functions of the severe accident analysis database system will be to make a diagnosis of the accident by some input information from the plant symptoms, to search a corresponding scenario, and finally to provide the user phenomenological information based on the pre-analyzed results. The MAAP 4.06 calculation results in this report will be utilized as input data of the severe accident analysis database system.

  17. IMPLEMENTING SMALL AND MEDIUM IT PROJECTS IN SMALL AND MEDIUM ENERPRISES

    Directory of Open Access Journals (Sweden)

    Felix DUMITRESCU

    2014-06-01

    Full Text Available Information technology is essential nowadays for all companies. Small enterprises are an important part of the economy and this article aims at providing some useful insight in implementing modern IT projects to their benefit. Due to the limited funding available for the IT infrastructure in most start-ups and small businesses, the projects should be adapted to fulfill the needs of the company for the lowest cost. The paper will start by defining small and medium project management theory and outlining the target of the study, small and medium sized companies. Next it will show a number of case studies of IT projects implemented in different types of small companies in Romania. Based on these implementations the article will draw some conclusions relevant to most small companies which need to design or improve their IT infrastructure.

  18. SURF imaging beams in an aberrative medium: Generation and postprocessing enhancement.

    Science.gov (United States)

    Näsholm, Sven Peter; Angelsen, Bjørn A J

    2012-11-01

    This paper presents numerical simulations of dual-frequency second-order ultrasound field (SURF) reverberation suppression transmit-pulse complexes. Such propagation was previously studied in a homogeneous medium. In this work, the propagation path includes a strongly aberrating body wall modeled by a sequence of delay screens. Each of the applied SURF transmit pulse complexes consists of a high-frequency 3.5-MHz imaging pulse combined with a low-frequency 0.5-MHz sound speed manipulation pulse. Furthermore, the feasibility of two signal postprocessing methods are investigated using the aberrated transmit SURF beams. These methods have previously been shown to adjust the depth of maximum SURF reverberation suppression within a homogeneous medium. The need for this study arises because imaging situations in which reverberation suppression is useful are also likely to produce pulse wave front distortion (aberration). Such distortions could potentially produce time delays that cancel the accumulated propagation time delay needed for the SURF reverberation suppression technique. Results show that both the generation of synthetic SURF reverberation suppression imaging transmit beams and the following postprocessing adjustments are attainable even when a body wall introduces time delays which are larger than previously reported delays measured on human body wall specimens.

  19. Incorporation of the university practice medium and its transformation into the community medium

    OpenAIRE

    Šula, Tomáš; Čada, Jan; Jurásek, Martin

    2015-01-01

    The contribution comprehensively describes an eight-year research process of incorporation of the university television broadcasting into the educational university process. The result is the implementation of a practice and community medium into the university structure. The sample process is verified on the basis of triangulation in a theoretical and empirical research with the analysis of a three-year operation of a university television broadcasting called the NEON TV on the ground of Tom...

  20. ATMEA and medium power reactors. The ATMEA joint venture and the ATMEA1 medium power reactor

    International Nuclear Information System (INIS)

    Mathet, Eric; Castello, Gerard

    2012-01-01

    This Power Point presentation presents the ATMEA company (a joint venture of Areva and Mitsubishi), the main features of its medium power reactor (ATMEA1) and its building arrangement, indicates the general safety objectives. It outlines the features of its robust design which aim at protecting, cooling down and containing. It indicates the regulatory and safety frameworks, comments the review of the safety options by the ASN and the results of this assessment

  1. A note on the effective medium theory of random resistive-reactive medium

    International Nuclear Information System (INIS)

    Kumar, N.; Jayannavar, A.M.

    1981-06-01

    The effective medium theory for a system with randomly distributed point conductivity and polarizability is re-formulated, with attention to cross-terms involving the two disorder parameters. The treatment reveals a certain inconsistency of the conventional theory owing to the neglect of the Maxwell-Wagner effect. The results are significant for the critical resistivity and dielectric anomalies of a binary liquid mixture at the phase-separation point. (author)

  2. Signal transmission in a human body medium-based body sensor network using a Mach-Zehnder electro-optical sensor.

    Science.gov (United States)

    Song, Yong; Hao, Qun; Zhang, Kai; Wang, Jingwen; Jin, Xuefeng; Sun, He

    2012-11-30

    The signal transmission technology based on the human body medium offers significant advantages in Body Sensor Networks (BSNs) used for healthcare and the other related fields. In previous works we have proposed a novel signal transmission method based on the human body medium using a Mach-Zehnder electro-optical (EO) sensor. In this paper, we present a signal transmission system based on the proposed method, which consists of a transmitter, a Mach-Zehnder EO sensor and a corresponding receiving circuit. Meanwhile, in order to verify the frequency response properties and determine the suitable parameters of the developed system, in-vivo measurements have been implemented under conditions of different carrier frequencies, baseband frequencies and signal transmission paths. Results indicate that the proposed system will help to achieve reliable and high speed signal transmission of BSN based on the human body medium.

  3. Gamma rays from the interstellar medium

    International Nuclear Information System (INIS)

    Bloemen, J.B.G.M.

    1985-01-01

    This thesis describes new gamma-ray views on cosmic rays and the interstellar medium. The author describes the COS-B data base and the pre-launch and in-flight calibration data used for all analyses. Diffuse galactic gamma radiation (> 50 MeV) may be either a result of cosmic-ray-matter interactions, or of the cosmic-ray electrons with the interstellar radiation field (mainly at optical and infrared wavelengths), through the inverse-Compton process. A detailed comparison between the gamma-ray observations of the large complex of interstellar clouds in Orion and Monoceros and the CO and HI surveys of this region is given. It gives insight into the cloud penetration of cosmic rays and in the relation between CO detections and molecular hydrogen column densities. Next, the radial distribution of gamma rays in the Galaxy is studied, as well as the galactic centre (more precisely, the central 400 pc), which contains a large concentration of CO molecules. The H 2 /CO abundance and the cosmic-ray density in the galactic centre are discussed and compared to the findings for the galactic disk. In various analyses in this thesis a likelihood-ratio method is applied for parameter estimation and hypothesis testing. A general description of this method is added as an appendix. (Auth.)

  4. Microscopic optical potential at medium energies

    International Nuclear Information System (INIS)

    Malecki, A.

    1979-01-01

    The problems concerning a microscopic optical model for the elastic nuclear collisions at medium energies are discussed. We describe the method for constructing the optical potential which makes use of the particular properties of quantum scattering in the eikonal limit. The resulting potential is expressed in terms of the nuclear wave functions and the nucleon-nucleon scattering amplitudes. This potential has a dynamic character since by including the effects of multiple scattering it allows for the possibility of intermediate excitations of the projectile and target nuclei. The use of the potential in the exact wave equation accounts for the most important mechanisms present in the collisions between composite particles. The microscopic optical model was successfully applied in the analysis of elastic scattering of protons and α-particles on atomic nuclei in the energy range of 300-1000 MeV/nucleon. The dynamic optical potential in this case represents a considerable improvement over the eikonal Glauber model and the static optical potential of Watson. The possibilities to extend the microscopic description of the proton-nucleus interaction by considering the spin dependence of the elementary amplitude and the Majorana exchange effects were investigated. (author)

  5. Magneto Binary Nanofluid Convection in Porous Medium

    Directory of Open Access Journals (Sweden)

    Jyoti Sharma

    2016-01-01

    Full Text Available The effect of an externally impressed magnetic field on the stability of a binary nanofluid layer in porous medium is considered in this work. The conservation equations related to the system are solved using normal mode technique and Galerkin method to analyze the problem. The complex expressions are approximated to get useful results. Mode of heat transfer is stationary for top heavy distribution of nanoparticles in the fluid layer and top heavy nanofluids are very less stable than regular fluids. Oscillatory motions are possible for bottom heavy distribution of nanoparticles and they are not much influenced by properties of different nanoparticles. A comparative analysis of the instability of water based nanofluids with metallic (Cu, Ag and semiconducting (TiO2, SiO2 nanoparticles under the influence of magnetic field is examined. Semiconducting nanofluids are found to be more stable than metallic nanofluids. Porosity destabilizes the layer while solute difference (at the boundaries of the layer stabilizes it. Magnetic field stabilizes the fluid layer system significantly.

  6. SILICATE COMPOSITION OF THE INTERSTELLAR MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Fogerty, S.; Forrest, W.; Watson, D. M.; Koch, I. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Sargent, B. A., E-mail: sfogerty@pas.rochester.edu [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2016-10-20

    The composition of silicate dust in the diffuse interstellar medium and in protoplanetary disks around young stars informs our understanding of the processing and evolution of the dust grains leading up to planet formation. An analysis of the well-known 9.7 μ m feature indicates that small amorphous silicate grains represent a significant fraction of interstellar dust and are also major components of protoplanetary disks. However, this feature is typically modeled assuming amorphous silicate dust of olivine and pyroxene stoichiometries. Here, we analyze interstellar dust with models of silicate dust that include non-stoichiometric amorphous silicate grains. Modeling the optical depth along lines of sight toward the extinguished objects Cyg OB2 No. 12 and ζ Ophiuchi, we find evidence for interstellar amorphous silicate dust with stoichiometry intermediate between olivine and pyroxene, which we simply refer to as “polivene.” Finally, we compare these results to models of silicate emission from the Trapezium and protoplanetary disks in Taurus.

  7. The physical state of the intergalactic medium

    International Nuclear Information System (INIS)

    Barcons, X.; Fabian, A.C.; Rees, M.J.

    1991-01-01

    Because the process of galaxy formation is most unlikely to be perfectly efficient, there is a strong possibility that some baryonic gas remains outside collapsed structures such as galaxies and clusters of galaxies. What fraction of the baryonic content of the Universe resides in this intergalactic medium (IGM) and what physical state it is in are open questions. Here we use observational limits on the density of neutral hydrogen in the IGM, on the lack of deviations from a black-body spectrum of the cosmic microwave background (MBR), and on the extragalactic component of the soft X-ray background (XRB) to constrain the state of the IGM. From the lack of MBR fluctuations, any energetic IGM (containing as much energy as the binding energy in galaxies) is inferred to be smoothly distributed on scales greater than galactic. This rules out hot IGM models for the origin of the hard X-ray background, as well as the hypothesis that cosmic explosions may have given rise to cosmological structure on scales larger than galaxies. (author)

  8. SILICATE COMPOSITION OF THE INTERSTELLAR MEDIUM

    International Nuclear Information System (INIS)

    Fogerty, S.; Forrest, W.; Watson, D. M.; Koch, I.; Sargent, B. A.

    2016-01-01

    The composition of silicate dust in the diffuse interstellar medium and in protoplanetary disks around young stars informs our understanding of the processing and evolution of the dust grains leading up to planet formation. An analysis of the well-known 9.7 μ m feature indicates that small amorphous silicate grains represent a significant fraction of interstellar dust and are also major components of protoplanetary disks. However, this feature is typically modeled assuming amorphous silicate dust of olivine and pyroxene stoichiometries. Here, we analyze interstellar dust with models of silicate dust that include non-stoichiometric amorphous silicate grains. Modeling the optical depth along lines of sight toward the extinguished objects Cyg OB2 No. 12 and ζ Ophiuchi, we find evidence for interstellar amorphous silicate dust with stoichiometry intermediate between olivine and pyroxene, which we simply refer to as “polivene.” Finally, we compare these results to models of silicate emission from the Trapezium and protoplanetary disks in Taurus.

  9. From medium-sized to megawatt turbines...

    Energy Technology Data Exchange (ETDEWEB)

    Dongen, W. van [NedWind bv, Rhenen (Netherlands)

    1996-12-31

    One of the world`s first 500 kW turbines was installed in 1989 in the Netherlands. This forerunner of the current NedWind 500 kW range also represents the earliest predesign of the NedWind megawatt turbine. After the first 500 kW turbines with steel rotor blades and rotor diameter of 34 m, several design modifications followed, e.g. the rotor diameter was increased to 35 m and a tip brake was added. Later polyester blades were introduced and the rotor diameter was increased with 5 in. The drive train was also redesigned. Improvements on the 500 kW turbine concept has resulted in decreased cost, whereas annual energy output has increased to approx. 1.3 million kWh. Wind energy can substantially contribute to electricity supply. Maximum output in kiloWatthours is the target. Further improvement of the existing technology and implementation of flexible components may well prove to be a way to increase energy output, not only in medium or large sized wind turbines. 7 figs.

  10. UV observations of local interstellar medium.

    Science.gov (United States)

    Kurt, V.; Mironova, E.; Fadeev, E.

    2008-12-01

    The methods of the interstellar matter study are described. The brief information of space missions aimed at observations in the unreachable for ground based telescopes UV spectral range (IUE, As- tron, HST and GALEX.) is presented. The history of discovery of H and He atoms entering the Solar System from the local interstellar medium (LISM) is given in brief. The results of observations performed by the group from Stern- berg Astronomical Institute (SAI MSU) and Space Research Institute (IKI RAS) performed with the help of the missions Prognoz-5, Prognoz-6 and the stations Zond-1, Venera and Mars and aimed at estimation of all basic LISM parameters (the velocity of the Sun in relation to LISM, directions of movement, densities of H and He atoms, LISM temperature) are presented. We also describe the present-day investigations of LISM performed with SOHO and ULYSSES mis- sions including the direct registration of He atoms entering the Solar System. The problem of interaction between the incoming flow of the ISM atoms ("in- terstellar wind") and the area of two shocks at the heliopause border (100-200 AU) is discussed. The LISM parameters obtained using the available data are presented in two tables.

  11. Learning intrinsic excitability in medium spiny neurons.

    Science.gov (United States)

    Scheler, Gabriele

    2013-01-01

    We present an unsupervised, local activation-dependent learning rule for intrinsic plasticity (IP) which affects the composition of ion channel conductances for single neurons in a use-dependent way. We use a single-compartment conductance-based model for medium spiny striatal neurons in order to show the effects of parameterization of individual ion channels on the neuronal membrane potential-curent relationship (activation function). We show that parameter changes within the physiological ranges are sufficient to create an ensemble of neurons with significantly different activation functions. We emphasize that the effects of intrinsic neuronal modulation on spiking behavior require a distributed mode of synaptic input and can be eliminated by strongly correlated input. We show how modulation and adaptivity in ion channel conductances can be utilized to store patterns without an additional contribution by synaptic plasticity (SP). The adaptation of the spike response may result in either "positive" or "negative" pattern learning. However, read-out of stored information depends on a distributed pattern of synaptic activity to let intrinsic modulation determine spike response. We briefly discuss the implications of this conditional memory on learning and addiction.

  12. Business Model Innovation for Small Medium Enterprises

    Directory of Open Access Journals (Sweden)

    Wirania Swasty

    2015-09-01

    Full Text Available Indonesian economy through Small Medium Enterprises (SMEs is expected to absorb labor and contribute to the growth of Gross Domestic Product. However, SMEs lack both managerial and technical skills. This research is about business model innovation for SMEs especially in fashion and garment industry. Study used qualitative approach by mentoring four selected SMEs in Babakan Penghulu Village– Cinambo Sub-District, Eastern Bandung. The tools used to analyze them including PEST analysis, Porter’s Five Forces,Resource Based View, Value Chain Analysis and Business Model Canvas. Finding suggests SMEs to have business model innovation derived from value proposition. SMEs should build their own brand awareness. Moreover, as garment and fashion industry, design can be a particularly important part of the Value Proposition. SMEs could communicate its value propositions and inform their service through its official websites and other social media. Since the intangible resources include brand and design, thus SMEs should build brand image and innovate year by year. SMEs must hire designers and launch a series of new products offers under the signature of their own brands. Ideation to strengthen strategies derives from value proposition building block as a starting point. Moreover, Business Model Canvas makes strategy more focused and measurable. Business model innovation is expected to increase overall performance of SMEs.

  13. Evaluation of insulin medium or chondrogenic medium on proliferation and chondrogenesis of ATDC5 cells.

    Science.gov (United States)

    Yao, Yongchang; Zhai, Zhichen; Wang, Yingjun

    2014-01-01

    The ATDC5 cell line is regarded as an excellent cell model for chondrogenesis. In most studies with ATDC5 cells, insulin medium (IM) was used to induce chondrogenesis while chondrogenic medium (CM), which was usually applied in chondrogenesis of mesenchymal stem cells (MSCs), was rarely used for ATDC5 cells. This study was mainly designed to investigate the effect of IM, CM, and growth medium (GM) on chondrogenesis of ATDC5 cells. ATDC5 cells were, respectively, cultured in IM, CM, and GM for a certain time. Then the proliferation and the chondrogenesis progress of cells in these groups were analyzed. Compared with CM and GM, IM promoted the proliferation of cells significantly. CM was effective for enhancement of cartilage specific markers, while IM induced the cells to express endochondral ossification related genes. Although GAG deposition per cell in CM group was significantly higher than that in IM and GM groups, the total GAG contents in IM group were the most. This study demonstrated that CM focused on induction of chondrogenic differentiation while IM was in favor of promoting proliferation and expression of endochondral ossification related genes. Combinational use of these two media would be more beneficial to bone/cartilage repair.

  14. Evaluation of Insulin Medium or Chondrogenic Medium on Proliferation and Chondrogenesis of ATDC5 Cells

    Directory of Open Access Journals (Sweden)

    Yongchang Yao

    2014-01-01

    Full Text Available Background. The ATDC5 cell line is regarded as an excellent cell model for chondrogenesis. In most studies with ATDC5 cells, insulin medium (IM was used to induce chondrogenesis while chondrogenic medium (CM, which was usually applied in chondrogenesis of mesenchymal stem cells (MSCs, was rarely used for ATDC5 cells. This study was mainly designed to investigate the effect of IM, CM, and growth medium (GM on chondrogenesis of ATDC5 cells. Methods. ATDC5 cells were, respectively, cultured in IM, CM, and GM for a certain time. Then the proliferation and the chondrogenesis progress of cells in these groups were analyzed. Results. Compared with CM and GM, IM promoted the proliferation of cells significantly. CM was effective for enhancement of cartilage specific markers, while IM induced the cells to express endochondral ossification related genes. Although GAG deposition per cell in CM group was significantly higher than that in IM and GM groups, the total GAG contents in IM group were the most. Conclusion. This study demonstrated that CM focused on induction of chondrogenic differentiation while IM was in favor of promoting proliferation and expression of endochondral ossification related genes. Combinational use of these two media would be more beneficial to bone/cartilage repair.

  15. Propagation and attenuation of Rayleigh waves in a semi-infinite unsaturated poroelastic medium

    Science.gov (United States)

    Lo, Wei-Cheng

    2008-10-01

    An analytical model for describing the propagation and attenuation of Rayleigh waves along the free surface of an elastic porous medium containing two immiscible, viscous, compressible fluids is developed in the present study based on the poroelastic equations formulated by Lo et al. [Lo WC, Sposito G, Majer E. Wave propagation through elastic porous media containing two immiscible fluids. Water Resour Res 2005;41:W02025]. The dispersion equation obtained is complex-valued due to viscous dissipation resulting from the relative motion of the solid to the pore fluids. As an excitation frequency is stipulated, the dispersion equation that is a cubic polynomial is numerically solved to determine the phase speed and attenuation coefficient of Rayleigh waves in Columbia fine sandy loam permeated by an air-water mixture. Our numerical results show that, corresponding to three dilatational waves, there is also the existence of three different modes of Rayleigh wave in an unsaturated porous medium, which are designated as the R1, R2, and R3 waves in descending order of phase speed, respectively. The phase speed of the R1 wave is non-dispersive (frequency-independent) in the frequency range we examined (10 Hz-10 kHz) and decreases as water saturation increases, whose magnitude ranges from 20% to 49% of that of the first dilatational wave with respect to water content. However, it is revealed numerically that the R2 and R3 waves are functions of excitation frequency. Given the same water saturation and excitation frequency, the phase speeds of the R2 and R3 waves are found to be approximately 90% of those of the second and third dilatational waves, respectively. The R1 wave has the lowest attenuation coefficient whereas the R3 wave attenuates highest.

  16. Design and evaluation of a flow-to-frequency converter circuit with thermal feedback

    Science.gov (United States)

    Pawlowski, Eligiusz

    2017-05-01

    A novel thermal flow sensor with a frequency output is presented. The sensor provides a pulse-train output whose frequency is related to the fluid flow rate around a self-heating thermistor. The integrating properties of the temperature sensor have been used, which allowed for realization of the pulse frequency modulator with a thermal feedback loop, stabilizing the temperature of the sensor placed in the flowing medium. The system assures a balance of the amount of heat supplied in the impulses to the sensor and the heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output pulse-train is proportional to the medium flow velocity around the sensor. The special feature of the presented solution is the total integration of the thermal sensor with the measurement signal conditioning system. i.e. the sensor and conditioning system are not separate elements of the measurement circuit, but constitute a whole in the form of a thermal heat-balance mode flow-to-frequency converter. The frequency signal from the converter may be directly connected to the microprocessor digital input, which with use of the standard built-in counters may convert the frequency into a numerical value of high precision. The sensor has been experimentally characterized as a function of the average flow velocity of air at room temperature.

  17. The effects of protoype medium on usability testing.

    Science.gov (United States)

    Boothe, Chase; Strawderman, Lesley; Hosea, Ethan

    2013-11-01

    Inconsistencies among testing methods and results in previous research prompted this study that builds upon a systematic usability testing research framework to better understand how interface medium influences users' abilities to detect usability flaws in applications. Interface medium was tested to identify its effects on users' perceptions of usability and abilities to detect usability problems and severe usability problems. Results indicated that medium has no effect on users' abilities to detect usability problems or perceptions of usability. However, results did indicate an interaction between the medium and the tested application in which users were able to identify significantly more usability problems on a higher fidelity medium using a particular application. Results also indicated that as users' perceptions of an application's usability increases, the users are less able to detect usability problems in that application. Usability testing should begin early in the design process, even if low fidelity mediums will be used. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  18. Nonlinear multi-frequency electromagnetic wave propagation phenomena

    Science.gov (United States)

    Valovik, Dmitry V.

    2017-11-01

    A generalisation of the concept of monochromatic electromagnetic waves guided by layered waveguide structures filled with non-linear medium is introduced. This generalisation leads to guided waves of a novel type: a non-linear multi-frequency guided wave. The existence of such waves, in particular guide structures, is proven using the perturbation method. Numerical experiments are presented for non-linear 1- and 2-frequency guided waves in plane and cylindrical (with a circular cross-section) waveguides. Numerically, a novel non-linear effect is found for particular cases of non-linear multi-frequency guided waves. The suggested generalisation gives not only a unified approach to treat various electromagnetic wave propagation problems but also paves the way to study non-linear interactions of guided waves.

  19. Effect of Acidity of a Medium on Riboflavin Photodestruction

    Science.gov (United States)

    Astanov, S. Kh.; Turdiev, M.; Sharipov, M. Z.; Kurtaliev, É. N.; Nizomov, N. N.

    2016-03-01

    Effect of acidity of a medium on the spectroscopic characteristics of riboflavin aqueous solutions is investigated by the method of fluorescent and absorption spectroscopy. Significant deformation of the electronic spectra of riboflavin aqueous solutions irradiated with unfiltered light of a PRK-2 lamp is observed. It is established that riboflavin photostability in an acid medium is about twice as much as the photostability in a neutral medium, which is caused by the formation of a protonated species.

  20. Small and medium size companies competiveness in Croatian regional framework

    OpenAIRE

    Zlatan Fröhlich

    2013-01-01

    Small and medium enterprises (SMEs) represent an important part of the Croatian economy. In 2011 SMEs achieved a share of 50.2% of gross domestic product (GDP), 65.5% of employment and 42% of Croatian exports. In the paper will be elaborated importance of the small and medium enterprise sector in Croatia as well as presented institutional and legislative framework for the small and medium enterprise sector in Croatia and describe distribution of competences for making policy decisions related...

  1. Effect of genotypes and culture medium on shoot regeneration and ...

    African Journals Online (AJOL)

    For proliferation, regenerated shoots in TDZ were subcultured in medium supplemented with 0.2, 0.4 and 0.6 mg/l TDZ, 2 mg/l BA or 2 mg/l Kin and regenerated shoots in BA were subcultured on the induction medium. In the second phase, mediums of MS, 1/2 MS, MS with 1/2 NH4NO3 and KNO3 concentration (MS-1/2N), ...

  2. Does Embryo Culture Medium Influence the Health and Development of Children Born after In Vitro Fertilization?

    Science.gov (United States)

    Bouillon, Céline; Léandri, Roger; Desch, Laurent; Ernst, Alexandra; Bruno, Céline; Cerf, Charline; Chiron, Alexandra; Souchay, Céline; Burguet, Antoine; Jimenez, Clément; Sagot, Paul; Fauque, Patricia

    2016-01-01

    In animal studies, extensive data revealed the influence of culture medium on embryonic development, foetal growth and the behaviour of offspring. However, this impact has never been investigated in humans. For the first time, we investigated in depth the effects of embryo culture media on health, growth and development of infants conceived by In Vitro Fertilization until the age of 5 years old. This single-centre cohort study was based on an earlier randomized study. During six months, in vitro fertilization attempts (No. 371) were randomized according to two media (Single Step Medium—SSM group) or Global medium (Global group). This randomized study was stopped prematurely as significantly lower pregnancy and implantation rates were observed in the SSM group. Singletons (No. 73) conceived in the randomized study were included (42 for Global and 31 for SSM). The medical data for gestational, neonatal and early childhood periods were extracted from medical records and parental interviews (256 variables recorded). The developmental profiles of the children in eight domains (social, self-help, gross motor, fine motor, expressive language, language comprehension, letter knowledge and number knowledge – 270 items) were compared in relation to the culture medium. The delivery rate was significantly lower in the SSM group than in the Global group (p<0.05). The culture medium had no significant effect on birthweight, risk of malformation (minor and major), growth and the frequency of medical concerns. However, the children of the Global group were less likely than those of the SSM group to show developmental problems (p = 0.002), irrespective of the different domains. In conclusion, our findings showed that the embryo culture medium may have an impact on further development. PMID:27008092

  3. Dust in the Diffuse Neutral Interstellar Medium

    Science.gov (United States)

    Sofia, Ulysses J.

    2008-05-01

    Studies of interstellar dust have always relied heavily upon Laboratory Astrophysics for interpretation. Laboratory values, in the broad sense that includes theory, are needed for the most basic act of measuring interstellar abundances, to the more complex determination of what grains are responsible for particular extinction. The symbiotic relationship between astronomical observations and Laboratory Astrophysics has prompted both fields to move forward, especially in the era of high-resolution ultraviolet spectroscopy when new elemental species could be interpreted and observations were able to show the limits of laboratory determinations. Thanks to this synergy, we currently have a good idea of the quantity of the most abundant elements incorporated into dust in diffuse neutral interstellar clouds: carbon, oxygen, iron, silicon and magnesium. Now the task is to figure out how, chemically and physically, those elements are integrated into interstellar grains. We can do this by comparing extinction curves to grain populations in radiative transfer models. The limitation at the present time is the availability of optical constants in the infrared through ultraviolet for species that are likely to exist in dust, i.e., those that are easy to form in the physical environments around stars and in molecular clouds. Extinction in some lines of sight can be fit within current abundance limits and with the optical constants that are available. However the inability to reproduce other extinction curves suggests that optical constants can be improved, either in quality for compounds that have been measured, or quantity in the sense of providing data for more materials. This talk will address the current state and the future of dust studies in the diffuse neutral interstellar medium. This work is supported by the grant HST-AR-10979.01-A from the Space Telescope Science Institute to Whitman College.

  4. Exploring the Interstellar Medium with SOFIA

    Science.gov (United States)

    Erickson, Edwin F.

    2004-01-01

    SOFIA, the Stratospheric Observatory for Infrared Astronomy, is being developed to operate at wavelengths from 0.3 microns to 1.6 mm over a 20 year lifetime. Its 2.5 m effective diameter telescope will be diffraction limited (approximately 8.5 arc seconds FWHM at 100 microns) at wavelengths beyond about 5 microns. Its B747SP aircraft platform will allow coverage of the entire sky and enable observation of ephemeral events. Nine first-generation focal plane instruments are being built, and more will be added later. These attributes assure SOFIA a vital role in future studies of the interstellar medium (ISM), in addition to topics such as the solar system. SOFIA observers will explore the gamut of ISM topics: star formation; the Galactic Center; debris disks; recycling of materials through the stellar life cycle; the origin and evolution of biogenic materials; shock, photodissociation, and photoexcitation physics; gas and grain chemistry. Imaging, spectroscopy, and eventually polarimetry covering much of the infrared spectrum will all be part of SOFIA's arsenal in the attack on these and other important problems. The talk will describe the observatory, its status, its science instruments and anticipated program. SOFIA is a joint program of NASA in the U.S. and DLR in Germany. Broad participation by the international science community in SOFIA observations will be encouraged via annual proposal opportunities and user-friendly tools. Roughly 80% of the observing time will be granted by the U.S. and 20% by Germany. For further information, see http://sofia.arc.nasa.gov.

  5. Hydrocarbons biodegradation in unsaturated porous medium

    International Nuclear Information System (INIS)

    Gautier, C.

    2007-12-01

    Biological processes are expected to play an important role in the degradation of petroleum hydrocarbons in contaminated soils. However, factors influencing the kinetics of biodegradation are still not well known, especially in the unsaturated zone. To address these biodegradation questions in the unsaturated zone an innovative experimental set up based on a physical column model was developed. This experimental set up appeared to be an excellent tool for elaboration of a structured porous medium, with well defined porous network and adjusted water/oil saturations. Homogeneous repartition of both liquid phases (i.e., aqueous and non aqueous) in the soil pores, which also contain air, was achieved using ceramic membranes placed at the bottom of the soil column. Reproducible interfaces (and connectivity) are developed between gas, and both non mobile water and NAPL phases, depending on the above-defined characteristics of the porous media and on the partial saturations of these three phases (NAPL, water and gas). A respirometric apparatus was coupled to the column. Such experimental set up have been validated with hexadecane in dilution in an HMN phase. This approach allowed detailed information concerning n-hexadecane biodegradation, in aerobic condition, through the profile of the oxygen consumption rate. We have taken benefit of this technique, varying experimental conditions, to determine the main parameters influencing the biodegradation kinetics and compositional evolution of hydrocarbons, under steady state unsaturated conditions and with respect to aerobic metabolism. Impacts of the nitrogen quantity and of three different grain sizes have been examined. Biodegradation of petroleum cut, as diesel cut and middle distillate without aromatic fraction, were, also studied. (author)

  6. On correctness of the two-level model for description of active medium in quantum plasmonics

    Science.gov (United States)

    Chubchev, E. D.; Andrianov, E. S.; Pukhov, A. A.; Vinogradov, A. P.; Lisyansky, A. A.

    2017-09-01

    In order to simplify the theoretical description of spasers, a gain medium is commonly represented by a two-level system (TLS). A realistic model, however, should have four levels. By using the Lindblad equations we develop a description of such a system and show that depending on ratios of the Rabi frequency and the rate of relaxation of the polarization, a four-level system (FLS) may be reduced to one of two effective TLSs that reproduce the key properties of a FLS.

  7. Eigenvalue approach to two dimensional coupled magneto-thermoelasticity in a rotating isotropic medium

    Science.gov (United States)

    Bayones, F. S.; Abd-Alla, A. M.

    This paper is devoted to two-dimensional problem of thermoelasticity dealing with thermoelastic wave propagation in a rotating medium with magnetic field effects and a time-dependent heat source effect due to thermomechanical source. The normal mode analysis and eigenvalue approach techniques are applied to solve the problem. The expressions of displacement, mean value of normal stress, dilatation and temperature are obtained in the domain. Numerical simulated results are depicted graphically to show the effect of magnetic field and rotation on resulting quantities. The results indicate that the effect of magnetic field, rotation, frequency, wave number and time are very pronounced.

  8. Chemically Defined Medium and Caenorhabditis elegans: A Powerful Approach

    Science.gov (United States)

    Szewczyk, N. J.; Kozak, E.; Conley, C. A.

    2003-01-01

    C. elegans has been established as a powerful genetic system. Growth in a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of me in large-scale growth and screening of animals. Here we present our initial results from developing culture systems with CeMM. We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats of using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change defined medium composition. As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  9. The Study of Birefringent Homogenous Medium with Geometric Phase

    International Nuclear Information System (INIS)

    Banerjee, Dipti

    2010-12-01

    The property of linear and circular birefringence at each point of the optical medium has been evaluated here from differential matrix N using the Jones calculus. This matrix lies on the OAM sphere for l = 1 orbital angular momentum. The geometric phase is developed by twisting the medium uniformly about the direction of propagation of the light ray. The circular birefringence of the medium, is visualized through the solid angle and the angular twist per unit thickness of the medium, k, that is equivalent to the topological charge of the optical element. (author)

  10. The influence of the interstellar medium on climate and life

    International Nuclear Information System (INIS)

    Talbot, R.J. Jr.

    1980-01-01

    Recent studies of the gas and dust between the stars, the interstellar medium, reveal a complex chemistry which indicates that prebiotic organic chemistry is ubiquitous. The relationship between this interstellar chemistry and the organic chemistry of the early solar system and the Earth is explored. The interstellar medium is also considered as likely to have a continuing influence upon the climate of the Earth and other planets. Life forms as known are not only descendants of the organic evolution begun in the interstellar medium, but their continuing evolution is also molded through occasional interactions between the interstellar medium, the Sun and the climate on Earth. (author)

  11. Medium component improvement for β-galactosidase production by ...

    African Journals Online (AJOL)

    Medium component improvement for β-galactosidase production by a probiotic strain Lactobacillus fermentum CM33. Wattana Sriphannam, Kridsada Unban, Hisashi Ashida, Kenji Yamamoto, Chartchai Khanongnuch ...

  12. Cultivation of tea fungus on malt extract medium

    Directory of Open Access Journals (Sweden)

    Cvetković Dragoljub D.

    2002-01-01

    Full Text Available The possibility of application of malt extract as a source of carbohydrate in a medium for tea fungus was investigated. The beverage obtained on such medium was compared with that prepared in a traditional way with sucrose medium. The presence of easily adoptable sugars, glucose and fructose, as dominant in malt medium results in a very effective fermentation, which gives much more sour beverage for the same time and makes it possible to reduce the fermentation period. The obtained beverage has satisfactory sensorial characteristics.

  13. Enclosed Small and Medium Caliber Firing Experimental Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility conducts completely instrumented terminal ballistics experimental tests with small and medium-caliber tungsten alloy penetrators against advanced armor...

  14. Sorbitol-MacConkey medium for detection of Escherichia coli O157:H7 associated with hemorrhagic colitis.

    Science.gov (United States)

    March, S B; Ratnam, S

    1986-05-01

    Escherichia coli serotype O157:H7 is a recently recognized human pathogen associated with hemorrhagic colitis. Unlike most E. coli strains, E. coli O157:H7 does not ferment sorbitol. Therefore, the efficacy of MacConkey agar containing sorbitol (SMAC medium) instead of lactose as a differential medium for the detection of E. coli O157:H7 in stool cultures was determined in comparison with MacConkey agar. The relative frequency of non-sorbitol-fermenting (NSF) organisms other than E. coli O157:H7 in feces was low at 10 to 20% (95% confidence limits), and NSF organisms also occurred mostly in small numbers. In a field trial involving over 1,000 diarrheal stools, E. coli O157:H7 was isolated from 18 stools, all of which were from patients with bloody diarrhea. In every instance, the growth of E. coli O157:H7 on SMAC medium was heavy and occurred in almost pure culture as colorless NSF colonies in contrast to fecal flora, which are mostly sorbitol fermenting and hence appear pink on this medium, whereas on MacConkey agar cultures, the growth of E. coli O157:H7 was indistinguishable from fecal flora. SMAC medium permitted ready recognition of E. coli O157:H7 in stool cultures. Detection of E. coli O157:H7 on SMAC medium had a sensitivity of 100%, a specificity of 85%, and an accuracy of 86%. SMAC medium stool culture is a simple, inexpensive, rapid, and reliable means of detecting E. coli O157:H7, and we recommend routine use of SMAC medium especially for culturing bloody stools.

  15. Solution pH change in non-uniform alternating current electric fields at frequencies above the electrode charging frequency.

    Science.gov (United States)

    An, Ran; Massa, Katherine; Wipf, David O; Minerick, Adrienne R

    2014-11-01

    AC Faradaic reactions have been reported as a mechanism inducing non-ideal phenomena such as flow reversal and cell deformation in electrokinetic microfluidic systems. Prior published work described experiments in parallel electrode arrays below the electrode charging frequency (fc ), the frequency for electrical double layer charging at the electrode. However, 2D spatially non-uniform AC electric fields are required for applications such as in plane AC electroosmosis, AC electrothermal pumps, and dielectrophoresis. Many microscale experimental applications utilize AC frequencies around or above fc . In this work, a pH sensitive fluorescein sodium salt dye was used to detect [H(+)] as an indicator of Faradaic reactions in aqueous solutions within non-uniform AC electric fields. Comparison experiments with (a) parallel (2D uniform fields) electrodes and (b) organic media were employed to deduce the electrode charging mechanism at 5 kHz (1.5fc ). Time dependency analysis illustrated that Faradaic reactions exist above the theoretically predicted electrode charging frequency. Spatial analysis showed [H(+)] varied spatially due to electric field non-uniformities and local pH changed at length scales greater than 50 μm away from the electrode surface. Thus, non-uniform AC fields yielded spatially varied pH gradients as a direct consequence of ion path length differences while uniform fields did not yield pH gradients; the latter is consistent with prior published data. Frequency dependence was examined from 5 kHz to 12 kHz at 5.5 Vpp potential, and voltage dependency was explored from 3.5 to 7.5 Vpp at 5 kHz. Results suggest that Faradaic reactions can still proceed within electrochemical systems in the absence of well-established electrical double layers. This work also illustrates that in microfluidic systems, spatial medium variations must be considered as a function of experiment time, initial medium conditions, electric signal potential, frequency, and

  16. Formation of ultrashort pulses from monochromatic XUV radiation via interaction with a medium of IR-dressed He atoms

    Science.gov (United States)

    Akhmedzhanov, Timur; Antonov, Vladimir; Kocharovskaya, Olga

    Trains of high intensity ultrashort XUV pulses could find a lot of applications. Recently, a mechanism of high efficiency formation of a train of XUV pulses from quasi-monochromatic XUV field was suggested. XUV field propagates through the medium of atoms, which are space-time modulated by IR field. The field scattered by modulated atoms contains sidebands of incident XUV field frequency and, for properly chosen parameters, train of ultrashort pulses is formed at the output of the medium. In this contribution, we study formation of ultrashort pulses in the medium of He atoms. Contrary to our recent work, IR field is chosen to be weak enough, so that pulses are formed due to modulation of excited atomic levels, rather than tunnel ionization. The suggested method allows to form train of pulses with high efficiency and can be scaled to He-like ions in order to get even shorter pulses.

  17. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  18. Two prototypes for medium rotation forestry harvesting

    Directory of Open Access Journals (Sweden)

    L. Pari

    2013-09-01

    Full Text Available Five years old poplar (Populus spp. plantation represents an interesting model of productivity. The most attractive characteristics of this energy crop are the handling flexibility, the high yield of biomass per area unit and the good quality of the chips obtainable. The mechanical harvesting of five-years old poplar plantations requires the use of specialized forest machineries such as harvester, feller, forwarder and chipper. Usually, after felling, the working phases consist of extraction, stacking and chipping. Generally, the last one is carried out in a “static phase”, where the product is taken from staked logs by using a hydraulic arm having a gripper that feed the chipping machine. In order to introduce technological innovations for the medium rotation forestry harvesting, the Consiglio per la Ricerca e la sperimentazione in Agricoltura, Unità di ricerca per l’Ingegneria agraria (CRAING of Monterotondo (Rome, Italy has developed a five years poplar cutwindrower and a self-propelled chipper equipped with a pick up system. The prototype of cut-windrower is a semi-trailed machine powered by a 95 kW tractor (at least. It mounts a cutting system and a double pincer with variable positioning. During the cutting phase the plant is grasped by the double pincer which conveys and unloads the stem along the inter-row. The trees are placed parallel to the progress of the tractor, but oriented in the opposite direction. The biomass windrowed is then chipped in a dynamic phase directly from the inter row using the self-propelled chipper equipped with the pick-up head. In the first tests, the cut-windrower has reached an operative working capacity of 0.22 ha h-1, with an operative production of 44 t h-1. On the other hand, the self-propelled chipper has showed an operative working capacity equal to 0.18 ha h-1, and an operative production of 35 t h-1 about. Both machines have shown good quality of the work performed and the results obtained

  19. Toward the detection of pure carbon clusters in the Interstellar Medium (ISM)

    Science.gov (United States)

    Heath, J. R.; Van Orden, A.; Hwang, H. J.; Kuo, E. W.; Tanaka, K.; Saykally, R. J.

    1995-01-01

    Determination of the form and distribution of carbon in the universe is critical to understanding the origin of life on Earth and elsewhere. Two potentially large reservoirs of carbon in the interstellar medium (ISM) remain unexplored. These are polycyclic aromatic hydrocarbons (PAH) and pure carbon clusters. Little information exists on the structures, properties, and transition frequencies of pure carbon clusters. The work described is designed to provide a specific inventory of laboratory frequencies and physical properties of this carbon clusters so that efforts can be made to detect them in cold interstellar sources by far-infrared astronomy. Data is given from infrared laser spectroscopy determination of the structure of C3, C4, C5, C6, C7, and C9.

  20. Thermal investigation of nanostructured bulk thermoelectric materials with hierarchical structures: An effective medium approach

    Science.gov (United States)

    Hao, Qing; Zhao, Hongbo; Xiao, Yue; Xu, Dongchao

    2018-01-01

    In recent years, hierarchical structures have been intensively studied as an effective approach to tailor the electron and phonon transport inside a bulk material for thermoelectric applications. With atomic defects and nano- to micro-scale structures in a bulk material, the lattice thermal conductivity can be effectively suppressed across the whole phonon spectrum, while maintaining or somewhat enhancing the electrical properties. For general materials with superior electrical properties, high thermoelectric performance can be achieved using hierarchical structures to minimize the lattice thermal conductivity. Despite many encouraging experimental results, accurate lattice thermal conductivity predictions are still challenging for a bulk material with hierarchical structures. In this work, an effective medium formulation is developed for nanograined bulk materials with embedded nanostructures for frequency-dependent phonon transport analysis. This new formulation is validated with frequency-dependent phonon Monte Carlo simulations. For high-temperature thermoelectric applications, nanograined bulk ZnO with embedded GaN nanoparticles is studied with the formulation.

  1. Corrosion resistant Ti alloy for sulphuric acid medium: Suitability of Ti-Mo alloys

    Energy Technology Data Exchange (ETDEWEB)

    Balusamy, T.; Jamesh, M.; Kumar, Satendra; Narayanan, T.S.N. Sankara [National Metallurgical Laboratory, Madras Centre, CSIR Complex, Taramani, Chennai 600 113 (India)

    2012-09-15

    The corrosion resistance of Ti-Mo (5, 10, 15 and 25 wt% molybdenum) alloys in 5-25% sulphuric acid was evaluated. The Ti-Mo alloys offered a better corrosion resistance than commercially pure titanium (CP-Ti). The higher impedance values, higher phase angle maximum, ability to reach the phase angle maximum at relatively lower frequencies, ability to exhibit a constant phase angle maximum over a wider range of frequencies, higher phase angle values at 0.01 Hz, have confirmed the formation of a stable passive oxide film on Ti-Mo alloys. The study recommends the use of Ti-Mo alloys, particularly Ti-25Mo alloy, as a suitable material of construction for sulphuric acid medium. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Human body and head characteristics as a communication medium for Body Area Network.

    Science.gov (United States)

    Kifle, Yonatan; Hun-Seok Kim; Yoo, Jerald

    2015-01-01

    An in-depth investigation of the Body Channel Communication (BCC) under the environment set according to the IEEE 802.15.6 Body Area Network (BAN) standard is conducted to observe and characterize the human body as a communication medium. A thorough measurement of the human head as part of the human channel is also carried out. Human forehead, head to limb, and ear to ear channel is characterized. The channel gain of the human head follows the same bandpass profile of the human torso and limbs with the maximum channel gain occurring at 35MHz. The human body channel gain distribution histogram at given frequencies, while all the other parameters are held constant, exhibits a maximum variation of 2.2dB in the channel gain at the center frequency of the bandpass channel gain profile.

  3. A multiple scattering theory for EM wave propagation in a dense random medium

    Science.gov (United States)

    Karam, M. A.; Fung, A. K.; Wong, K. W.

    1985-01-01

    For a dense medium of randomly distributed scatterers an integral formulation for the total coherent field has been developed. This formulation accounts for the multiple scattering of electromagnetic waves including both the twoand three-particle terms. It is shown that under the Markovian assumption the total coherent field and the effective field have the same effective wave number. As an illustration of this theory, the effective wave number and the extinction coefficient are derived in terms of the polarizability tensor and the pair distribution function for randomly distributed small spherical scatterers. It is found that the contribution of the three-particle term increases with the particle size, the volume fraction, the frequency and the permittivity of the particle. This increase is more significant with frequency and particle size than with other parameters.

  4. Criteria for Selection of Frequency of Electromagnetic Radiation for Underwater proximity Fuzes

    OpenAIRE

    Sanagapallea Koteswara Rao

    1991-01-01

    Electromagnetic proximity fuzes play important role in underwater weapons. The characteristics of the electromagnetic field, i.e., the wavelength, penetration, propagation constant, velocity, etc in sea water are different from those in air. The conducting properties of the medium are strongly dependent on the frequency of the electromagnetic waves. This paper highlights the basis for selection of frequency of electromagnetic propagation for such applications as proximity fuze for unde...

  5. Fast simulation approaches for power fluctuation model of wind farm based on frequency domain

    DEFF Research Database (Denmark)

    Lin, Jin; Gao, Wen-zhong; Sun, Yuan-zhang

    2012-01-01

    This paper discusses one model developed by Riso, DTU, which is capable of simulating the power fluctuation of large wind farms in frequency domain. In the original design, the “frequency-time” transformations are time-consuming and might limit the computation speed for a wind farm of large size....... is more than 300 times if all these approaches are adopted, in any low, medium and high wind speed test scenarios....

  6. Binaural beats at high frequencies.

    Science.gov (United States)

    McFadden, D; Pasanen, E G

    1975-10-24

    Binaural beats have long been believed to be audible only at low frequencies, but an interaction reminiscent of a binaural beat can sometimes be heard when different two-tone complexes of high frequency are presented to the two ears. The primary requirement is that the frequency separation in the complex at one ear be slightly different from that in the other--that is, that there be a small interaural difference in the envelope periodicities. This finding is in accord with other recent demonstrations that the auditory system is not deaf to interaural time differences at high frequencies.

  7. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  8. A graphene based frequency quadrupler

    Science.gov (United States)

    Cheng, Chuantong; Huang, Beiju; Mao, Xurui; Zhang, Zanyun; Zhang, Zan; Geng, Zhaoxin; Xue, Ping; Chen, Hongda

    2017-04-01

    Benefit from exceptional electrical transport properties, graphene receives worldwide attentions, especially in the domain of high frequency electronics. Due to absence of effective bandgap causing off-state the device, graphene material is extraordinarily suitable for analog circuits rather than digital applications. With this unique ambipolar behavior, graphene can be exploited and utilized to achieve high performance for frequency multipliers. Here, dual-gated graphene field-effect transistors have been firstly used to achieve frequency quadrupling. Two Dirac points in the transfer curves of the designed GFETs can be observed by tuning top-gate voltages, which is essential to generate the fourth harmonic. By applying 200 kHz sinusoid input, arround 50% of the output signal radio frequency power is concentrated at the desired frequency of 800 kHz. Additionally, in suitable operation areas, our devices can work as high performance frequency doublers and frequency triplers. Considered both simple device structure and potential superhigh carrier mobility of graphene material, graphene-based frequency quadruplers may have lots of superiorities in regards to ultrahigh frequency electronic applications in near future. Moreover, versatility of carbon material system is far-reaching for realization of complementary metal-oxide-semiconductor compatible electrically active devices.

  9. Two-dimensional static deformation of an anisotropic medium

    Indian Academy of Sciences (India)

    The problem of two-dimensional static deformation of a monoclinic elastic medium has been studied using the eigenvalue method, following a Fourier transform. We have obtained expressions for displacements and stresses for the medium in the transformed domain. As an application of the above theory, the particular ...

  10. Development of a minimal growth medium for Lactobacillus plantarum

    NARCIS (Netherlands)

    Wegkamp, H.B.A.; Teusink, B.; Vos, de W.M.; Smid, E.J.

    2010-01-01

    Aim: A medium with minimal requirements for the growth of Lactobacillus plantarum WCFS was developed. The composition of the minimal medium was compared to a genome-scale metabolic model of L. plantarum. Methods and Results: By repetitive single omission experiments, two minimal media were

  11. Novel culture medium for the axenic growth of Balamuthia mandrillaris.

    Science.gov (United States)

    Lares-Jiménez, Luis Fernando; Gámez-Gutiérrez, Ricardo Alfredo; Lares-Villa, Fernando

    2015-08-01

    Until now, for axenic cultivation of Balamuthia mandrillaris, the BM-3 culture medium and the Modified Chang's special medium have been the only ones recommended, but they have some disadvantages, as both require many components and their preparations are laborious. Therefore, we developed a novel culture medium for B. mandrillaris axenic cultivation. Each one of the 11 components of BM-3 was combined with Cerva's medium as basal culture medium. Ten strains of B. mandrillaris including the reference strain CDC:V039 and 9 environmental isolates were used during trials. After testing all combinations, the basal medium complemented with 10× Hank's balanced salt solution was the only one that supported confluent growth of B. mandrillaris. Cell shape and motility of trophozoites were normal. This developed medium is as useful as BM-3 for axenization. The development of a cheaper and easy-to-prepare medium for B. mandrillaris opens the possibility of increasing its study. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Horizontal and vertical projectile motion in a resistant medium ...

    African Journals Online (AJOL)

    A study of projectile motion in a resistant medium subject to varying path angles and speed was carried out. Solutions to the governing equations of motion is developed employing double integration. Analysis of the results shows that the path of the particle in a resistant medium is affected by both increase in path angle and ...

  13. Optical activity via Kerr nonlinearity in a spinning chiral medium

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Anwar Ali, E-mail: anwarali@uom.edu.pk [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Bacha, Bakht Amin, E-mail: aminoptics@gmail.com [Department of Physics, University of Malakand at Chakdara Dir(L) (Pakistan); Khan, Rahmat Ali, E-mail: rahmat_alipk@yahoo.com [Department of Mathematics, University of Malakand (Pakistan)

    2016-11-11

    Optical activity is investigated in a chiral medium by employing the four level cascade atomic model, in which the optical responses of the atomic medium are studied with Kerr nonlinearity. Light entering into a chiral medium splits into circular birefringent beams. The angle of divergence between the circular birefringent beams and the polarization states of the two light beams is manipulated with Kerr nonlinearity. In the stationary chiral medium the angle of divergence between the circular birefringent beams is calculated to be 1.3 radian. Furthermore, circular birefringence is optically controlled in a spinning chiral medium, where the maximum rotary photon drag angle for left (right) circularly polarized beam is ±1.1 (±1.5) microradian. The change in the angle of divergence between circular birefringent beams by rotary photon drag is calculated to be 0.4 microradian. The numerical results may help to understand image designing, image coding, discovery of photonic crystals and optical sensing technology. - Highlights: • Coherent control of a circular birefringence in a chiral medium is studied. • Angle of divergence between birefringent beams is modified with Kerr nonlinearity. • Rotary photon drag is controlled for birefringent beams and enhanced with Kerr nonlinearity in a spinning medium. • Rotation of the angle of divergence is observed with mechanical rotation of the medium about an axis and modified with Kerr effect. • A change in the angle of divergence is calculated by about a microradian with rotary photon drag.

  14. Palm kernel agar: An alternative culture medium for rapid detection ...

    African Journals Online (AJOL)

    The feasibility of using palm kernel agar (PKA) as an alternative culture medium to desiccated coconut agar (DCA), the conventional medium for the recovery of aflatoxigenic fungi from mixed cultures and the detection of aflatoxigenic fungi and direct visual determination of aflatoxins in agricultural commodities was ...

  15. Wave velocities in a pre-stressed anisotropic elastic medium

    Indian Academy of Sciences (India)

    Wave velocities in a pre-stressed anisotropic elastic medium. M D Sharma ... Modified Christoffel equations are derived for three-dimensional wave propagation in a general anisotropic medium under initial stress.The three roots of a ... Department of Mathematics, Kurukshetra University, Kurukshetra 136 119, India. UIET ...

  16. An improvised medium for axenic cultivation of Acanthamoeba spp.

    OpenAIRE

    Kirti Megha; Amit Gupta; Rakesh Sehgal; Sumeeta Khurana

    2017-01-01

    Acanthamoebae can be easily grown in bacterised cultures, but their growth in axenic media is tedious and many times unsuccessful. We thus experimented with some additives in the conventional axenic medium for growth of various isolates of Acanthamoeba. Addition of Torula yeast RNA was found to significantly enhance the growth of Acanthamoebae in the axenic culture medium.

  17. Medium response to jets in heavy ion collisions

    Science.gov (United States)

    Tachibana, Yasuki

    2018-01-01

    A short overview on recent progress in studies of medium response to jet quenching in heavy ion collisions is presented. We show the typical features of medium response and give comment on their connection to jet observables by introducing the work done by the author and collaborators as an example.

  18. Can small, medium and micro enterprises contribute to tourism ...

    African Journals Online (AJOL)

    However, tourism in Butha-Buthe is under-developed, and it is very important to identify tourism's potential in this area, and explore how small, medium and micro enterprises (SMMEs) could contribute to the development of the industry. The study examines the economic role of small, medium and micro enterprises towards ...

  19. Radiation sensitive medium for recording an absorbed dose distribution

    DEFF Research Database (Denmark)

    2017-01-01

    The invention relates to a radiation sensitive medium for recording an absorbed dose distribution from an external radiation source such as e.g. a linear particle accelerator used for e.g. cancer treatment or radiation processing. The invention further relates to a method for measuring the absorbed...... doses distribution in a radiation sensitive medium....

  20. Gender Variance and the Performance of Small and Medium Scale ...

    African Journals Online (AJOL)

    Small and medium scale industries usually tend to develop and grow into medium and large scale industries. This form of growth yields to the development of the economy. However, thesuccess of SMEs depends on the effort of the entrepreneurs through concerted effort of financing and effective managerial skills.

  1. Medium-term carbohydrate tolerance improves and then ...

    African Journals Online (AJOL)

    Background: It has been reported that carbohydrate metabolism does not deteriorate in pregnancy in the African, an observation at variance with general teaching. Objective: To determine the effect of pregnancy on medium term carbohydrate metabolism. Methods: Medium term carbohydrate metabolism was evaluated in ...

  2. English medium of instruction: A situation analysis | Uys | South ...

    African Journals Online (AJOL)

    The majority of learners in southern Africa receive their education through the medium of a second language, English. Although teachers of English play a crucial role in helping learners to acquire language skills in the medium of instruction, we argue that subject content teachers' lack of attention to the teaching of the four ...

  3. Diamonds are not forever : Botswana medium-term fiscal sustainability

    OpenAIRE

    Kojo, Naoko C.

    2010-01-01

    This paper analyzes Botswana's medium-term fiscal sustainability in view of the expected depletion of diamonds in the future. The analysis shows that in the absence of policy adjustments, Botswana's current fiscal policy strategy is unsustainable over the longer term, which could endanger macroeconomic stability and Botswana's reputation as Africa's success story. Ensuring medium-term sust...

  4. Coupling of Elastic Isotropic Medium Parameters in Iterative Linearized Inversion

    NARCIS (Netherlands)

    Anikiev, D.V.; Kashtan, B.M.; Mulder, W.A.; Troyan, V.N.

    2014-01-01

    An elastic isotropic medium is described with three parameters. In seismic migration the perturbation of one elastic parameter affects the images of all the three, which means that these parameters are coupled. For an effective quantitative reconstruction of the true elastic medium reflectivity one

  5. Tap Water Hydraulic Systems for Medium Power Applications

    DEFF Research Database (Denmark)

    Conrad, Finn; Adelstorp, Anders

    1998-01-01

    Presentation of new range of developed tap water hydraulic componets and applications for medium power up to 4 kW and 50 bar.......Presentation of new range of developed tap water hydraulic componets and applications for medium power up to 4 kW and 50 bar....

  6. The ribose and glycine Maillard reaction in the interstellar medium ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 120; Issue 3. The ribose and glycine Maillard reaction in the interstellar medium (ISM): A theoretical study. Abraham F Jalbout Md Abul Haider ... Keywords. Density functional computational study; ribose; glycine; Maillard reaction; gaseous phase interstellar medium.

  7. Wave velocities in a pre-stressed anisotropic elastic medium

    Indian Academy of Sciences (India)

    Modified Christoffel equations are derived for three-dimensional wave propagation in a general anisotropic medium under initial stress.The three roots of a cubic equation define the phase velocities of three quasi-waves in the medium.Analytical expressions are used to calculate the directional derivatives of phase ...

  8. An improvised medium for axenic cultivation ofAcanthamoebaspp.

    Science.gov (United States)

    Megha, Kirti; Gupta, Amit; Sehgal, Rakesh; Khurana, Sumeeta

    2017-01-01

    Acanthamoebae can be easily grown in bacterised cultures, but their growth in axenic media is tedious and many times unsuccessful. We thus experimented with some additives in the conventional axenic medium for growth of various isolates of Acanthamoeba. Addition of Torula yeast RNA was found to significantly enhance the growth of Acanthamoebae in the axenic culture medium.

  9. Optimization of growth medium and fermentation conditions for ...

    African Journals Online (AJOL)

    A sequential optimization approach based on statistical experimental designs was employed to optimize growth medium and fermentation conditions, in order to improve the antibiotic activity of Xenorhabdus nematophila TB. Tryptone soyptone broth (TSB) was chosen as the original medium for optimization. Glucose and ...

  10. An improvised medium for axenic cultivation of Acanthamoeba spp.

    Directory of Open Access Journals (Sweden)

    Kirti Megha

    2017-01-01

    Full Text Available Acanthamoebae can be easily grown in bacterised cultures, but their growth in axenic media is tedious and many times unsuccessful. We thus experimented with some additives in the conventional axenic medium for growth of various isolates of Acanthamoeba. Addition of Torula yeast RNA was found to significantly enhance the growth of Acanthamoebae in the axenic culture medium.

  11. Effect of Basal Medium, Explants Size and Density on the In Vitro Proliferation and Growth of Date Palm (Phoenix dactylifera L. Cultivar ‘16-bis’

    Directory of Open Access Journals (Sweden)

    Mouaad Amine MAZRI

    2013-08-01

    Full Text Available The effect of basal medium, explant size and density on shoot multiplication, growth, rooting and acclimatization of date palm cv. ‘16-bis’ was evaluated. Bud clusters of different sizes (2, 3, 4 and 5 buds per cluster were cultured at density of 1, 2, 3 and 4 clusters on Murashige and Skoog medium (MS, woody plant medium (WPM and Nitsch medium (NM supplemented with 0.5 mg/L 2-naphthoxyacetic acid and 0.5 mg/L kinetin for three months (multiplication phase. Separated shoots of different sizes (<3 cm; 3 to 4.5 cm and 4.5 to 6 cm were cultured at density of 1, 2, 3 and 4 shoots on hormone free MS medium, WPM or NM for three months (Elongation-rooting phase. The proliferation and development of shoots were affected by the basal medium, explant size and density. The optimal shoot proliferation (18.1 was observed when 4 buds clusters were cultured at the density of 2 clusters per jar in MS medium. Separated shoots of 4.5 to 6 cm length exhibited the optimal in vitro development in terms of leaf length and greening, and root number and length when cultured on MS medium. In addition, these shoots reached the highest acclimation frequency with 80%. Our results would be utilized for an efficient propagation of plantlets of cv. ‘16-bis’, a selected date palm cultivar resistant to the bayoud disease.

  12. High frequency magnetic field technique: mathematical modelling and development of a full scale water fraction meter

    Energy Technology Data Exchange (ETDEWEB)

    Cimpan, Emil

    2004-09-15

    This work is concerned with the development of a new on-line measuring technique to be used in measurements of the water concentration in a two component oil/water or three component (i.e. multiphase) oil/water/gas flow. The technique is based on using non-intrusive coil detectors and experiments were performed both statically (medium at rest) and dynamically (medium flowing through a flow rig). The various coil detectors were constructed with either one or two coils and specially designed electronics were used. The medium was composed by air, machine oil, and water having different conductivity values, i.e. seawater and salt water with various conductivities (salt concentrations) such as 1 S/m, 4.9 S/m and 9.3 S/m. The experimental measurements done with the different mixtures were further used to mathematically model the physical principle used in the technique. This new technique is based on measuring the coil impedance and signal frequency at the self-resonance frequency of the coil to determine the water concentration in the mix. By using numerous coils it was found, experimentally, that generally both the coil impedance and the self-resonance frequency of the coil decreased as the medium conductivity increased. Both the impedance and the self-resonance frequency of the coil depended on the medium loss due to the induced eddy currents within the conductive media in the mixture, i.e. water. In order to detect relatively low values of the medium loss, the self-resonance frequency of the coil and also of the magnetic field penetrating the media should be relatively high (within the MHz range and higher). Therefore, the technique was called and referred to throughout the entire work as the high frequency magnetic field technique (HFMFT). To practically use the HFMFT, it was necessary to circumscribe an analytical frame to this technique. This was done by working out a mathematical model that relates the impedance and the self-resonance frequency of the coil to the

  13. Hydrogenic systems for calculable frequency standards. Status and options

    International Nuclear Information System (INIS)

    Flowers, J.; Klein, H.; Knight, D.

    2001-01-01

    The study of hydrogen and hydrogenic (one-electron) ions is an area of rapid progress and one of great potential for future frequency standards. In 1997, the two-photon 1S-2S transition in the hydrogen atom was included in the list of approved radiations for the practical realisation of the metre, and since then revolutions in optical frequency metrology have reduced the uncertainty in its frequency by more than an order of magnitude, to 1.8 parts in 10 14 . Hydrogenic systems are simple enough that the frequencies of their transitions can be calculated in terms of the Rydberg constant with an accuracy that can approach or exceed the measurement uncertainty. Transitions in such systems can be thought of as forming a natural frequency scale, and offer the prospect of a set of quantum frequency standards which are directly related to the fundamental constants. The Rydberg constant is currently best determined from optical frequency measurements in hydrogen. However, to take full advantage of the recent high accuracy 1S-2S frequency measurement requires: Improved measurements of other transition frequencies in the hydrogen atom; Reduced uncertainty in the quantum electrodynamic (QED) contributions to the energy levels, in particular the two-loop binding corrections; An improved value for the proton charge radius. In He + and one-electron systems of higher atomic number Z, the two-loop binding corrections are a fractionally larger part of the Lamb shift due to their rapid scaling with Z. Measurements of the Lamb shift in medium-Z hydrogenic ions can therefore provide tests of these corrections, and feed in to the theoretical understanding of hydrogen itself Although both theory and experiment are less accurate at higher Z, there is the potential for a new range of X-ray standards, providing that the QED corrections are well understood and new absolute measurement techniques can be developed. A number of areas are suggested for future investigation: Improving the

  14. Small and medium business in the contractual relationship system

    Directory of Open Access Journals (Sweden)

    Obalyaeva Julia, I.

    2015-01-01

    Full Text Available The paper reveals the role of small and medium business in the national economy. The comparative analysis of the indicators characterizing the development of small business in Russia, South Korea and France is given are compared. Two laws that support small and medium businesses in public purchasing. The author’s vision of the problems of development of small and medium-sized businesses in the Russian Federation and specification of the path of the national economy development is presented. Two schemes, revealing the organization of interaction of large corporate sector and the sector of small and medium-sized enterprises in the system of contractual relations and analysis of internal and external factors in the development of small and medium-sized enterprises are presented. The experience of conducting digital auctions with participation of small businesses on an digital platform CJSC "Sberbank AST" is considered.

  15. Isogeometric frictionless contact analysis with the third medium method

    Science.gov (United States)

    Kruse, R.; Nguyen-Thanh, N.; Wriggers, P.; De Lorenzis, L.

    2018-01-01

    This paper presents an isogeometric formulation for frictionless contact between deformable bodies, based on the recently proposed concept of the third medium. This concept relies on continuum formulations not only for the contacting bodies but also for a fictitious intermediate medium in which the bodies can move and interact. Key to the formulation is a suitable definition of the constitutive behavior of the third medium. In this work, based on a number of numerical tests, the role of the material parameters of the third medium is systematically assessed. We also assess the rate of spatial convergence for higher-order discretizations, stemming from the regularization of the non-smooth contact problem inherent to the third medium approach. Finally, problems with self contact are considered and turn out to be an attractive application of the method.

  16. System and method for treatment of a medium

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Surinder Prabhjot; Acharya, Harish Radhakrishna; Perry, Robert James; McDermott, John Brian

    2017-05-23

    A system and method for treatment of a medium is disclosed. The system includes a plurality of separator zones and a plurality of heat transfer zones. Each of the separator zone and the heat transfer zone among the plurality of separator zones and heat transfer zones respectively, are disposed alternatively in a flow duct. Further, each separator zone includes an injector device for injecting a sorbent into the corresponding separator zone. Within the corresponding separator zone, the injected sorbent is reacted with a gaseous medium flowing in the flow duct, so as to generate a reacted gaseous medium and a reacted sorbent. Further, each heat transfer zone exchanges heat between the reacted gaseous medium fed from the corresponding separator zone and a heat transfer medium.

  17. Bacterial growth on Mueller Hinton medium sterilized by. gamma. -radiation

    Energy Technology Data Exchange (ETDEWEB)

    Eisenberg, E. (Israel Atomic Energy Commission, Yavne. Soreq Nuclear Research Center); Bogokowsky, B.; Altmann, G. (Sheba Medical Center, Tel Hashomer (Israel); Tel Aviv Univ. (Israel). Medical School)

    1981-12-01

    The possibility of radiosterilization of culture media for the cultivation of bacteria was investigated. Mueller Hinton agar, a medium widely used for the propagation of some fastidious pathogenic bacteria, was sterilized with 1.0 and 1.5 Mrad doses of ..gamma..-radiation. Bacteria belonging to seven different species grew as well on the radiosterilized medium as on medium sterilized by heat in a conventional way. Reduction in colony size was observed on the radiosterilized medium with Staphylococcus aureus and Shigella boydii. Neisseria meningitidis, the most fastidious bacterium tested, did not grow at all. The addition of small amounts of catalase corrected the deleterious radiation effect and all bacteria tested could be successfully grown on irradiated Mueller Hinton agar supplemented with up to 11 Keil units catalase per liter medium.

  18. van der Waals interactions in a magnetodielectric medium

    International Nuclear Information System (INIS)

    Spagnolo, S.; Dalvit, D. A. R.; Milonni, P. W.

    2007-01-01

    The van der Waals interaction between two ground-state atoms is calculated for two electrically or magnetically polarizable particles embedded in a dispersive magnetodielectric medium. Unlike previous calculations which infer the atom-atom interaction from the dilute-medium limit of the macroscopic, many-body van der Waals interaction, the interaction is calculated directly for the system of two atoms in a magnetodielectric medium. Two approaches are presented, the first based on the quantized electromagnetic field in a dispersive medium without absorption and the second on Green functions that allow for absorption. We show that the correct van der Waals interactions are obtained regardless of whether absorption in the host medium is explicitly taken into account

  19. Method for imaging with low frequency electromagnetic fields

    Science.gov (United States)

    Lee, Ki H.; Xie, Gan Q.

    1994-01-01

    A method for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The traveltimes corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter .alpha. for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography.

  20. Low-Frequency Radio Bursts and Space Weather

    Science.gov (United States)

    Gopalswamy, N.

    2016-01-01

    Low-frequency radio phenomena are due to the presence of nonthermal electrons in the interplanetary (IP) medium. Understanding these phenomena is important in characterizing the space environment near Earth and other destinations in the solar system. Substantial progress has been made in the past two decades, because of the continuous and uniform data sets available from space-based radio and white-light instrumentation. This paper highlights some recent results obtained on IP radio phenomena. In particular, the source of type IV radio bursts, the behavior of type III storms, shock propagation in the IP medium, and the solar-cycle variation of type II radio bursts are considered. All these phenomena are closely related to solar eruptions and active region evolution. The results presented were obtained by combining data from the Wind and SOHO missions.

  1. High-frequency asymptotics of the emission spectrum of moving charged particles in classical electrodynamics

    International Nuclear Information System (INIS)

    Abbasov, I.I.; Bolotovskij, B.M.; Davydov, V.A.

    1986-01-01

    Electromagnetic radiation appears as a result of a charged particle movement in free space and also in heterogeneous and non-stationary medium. The radiation spectrum depends on the charged particle motion law, as well as on the law of the medium property chage in space and time. The asymptotics of radiation spectrum, i.e. behaviour of spectral intensity at high frequencies, is studied. It is shown that if a charged particle moves along smooth trajectory or if the change in the medium properties takes place accordng to the law described by a smooth function, the radiation spectrum at high frequencies decreases according to exponential law. Thus, radiation spectrum of a charged particle moving along a smooth trajectory in the medium with gradual heterogeneity and (or) instability is rapidly cut, starting from a certain frequency value. The smooth trajectory means that the charge moves according to the law r = r(t), where vector-function r(t) is continuous with all its derivatives. In much the same way the medium with gradual heterogeneities (or with gradual instability) is described by the functions which are continuous with all their derivatives of any order. The method permitting to determine the upper boundary of radiation spectra is presented

  2. Growth inhibition of Staphylococcus aureus induced by low-frequency electric and electromagnetic fields.

    Science.gov (United States)

    Obermeier, Andreas; Matl, Florian Dominik; Friess, Wolfgang; Stemberger, Axel

    2009-05-01

    Magnetic field therapy is an established technique in the treatment of pseudarthrosis. In cases of osteomylitis, palliation is also observed. This study focuses on the impact of different electric and electromagnetic fields on the growth of Staphylococcus aureus by in vitro technologies. Cultures of Staphylococcus aureus in fluid and gel-like medium were exposed to a low-frequency electromagnetic field, an electromagnetic field combined with an additional electric field, a sinusoidal electric field and a static electric field. In gel-like medium no significant difference between colony-forming units of exposed samples and non-exposed references was detected. In contrast, Staphylococcus aureus concentrations in fluid medium could clearly be reduced under the influence of the four different applied fields within 24 h of experiment. The strongest effects were observed for the direct current electric field which could decrease CFU/ml of 37%, and the low-frequency electromagnetic field with additional induced electric alternating field with a decrease of Staphylococci concentration by 36%. The effects of the electromagnetic treatment on Staphylococci within fluid medium are significantly higher than in gel-like medium. The application of low-frequency electromagnetic fields corroborates clinical situations of bone infections during magnetic field therapy. Copyright 2009 Wiley-Liss, Inc.

  3. Switchable and tunable microwave frequency multiplication based on a dual-passband microwave photonic filter.

    Science.gov (United States)

    Chen, Hao; Xu, Zuowei; Fu, Hongyan; Zhang, Shiwei; Wu, Congxian; Wu, Hao; Xu, Huiying; Cai, Zhiping

    2015-04-20

    In this paper, a novel approach to implement switchable and tunable microwave frequency multiplication has been proposed and experimentally demonstrated. High order harmonics of microwave signal with external modulation technique can be selected by using a novel switchable dual-passband microwave photonic filter (MPF) based on a modified fiber Mach-Zehnder interferometer (FMZI) and a dispersive medium. By adjusting the polarization controllers in the modified FMZI, the passbands of the MPF can switch between lower frequency, higher frequency or dual-passband states, and by changing the length of the variable optical delay line (VODL) in the modified FMZI, the central frequencies of these passbands can also be tuned. Therefore, tunable and switchable microwave signal frequency multiplication can be achieved. The experimental results show that by modulating a driving signal with frequency of 2.5 GHz, a signal with frequency of 7.5 GHz, which is three times of the driving frequency, the other one with the frequency of 15 GHz, which is six times of the driving frequency can be generated and freely switchable between two frequencies and dual frequency states by simply adjusting the polarization controllers in the modified FMZI.

  4. Effect of explant density and medium culture volumes on cassava micropropagation in Temporal Immersion System

    Directory of Open Access Journals (Sweden)

    Milagros Basail

    2003-04-01

    Full Text Available Due to the need of producing high quality planting material available to cassava growers, it has been necessary to look for alternatives in order to increase the efficiancy of in vitro propagation methods and their automation, such as the use of the Temporal Immersion Systems (RITA®. This work was carried out to increase the multiplication coefficient for cassava mass propagation through out Temporal Immersion Systems. The clone ‘CMC-40’ was used. Different medium volumes per explant, and material density per unit at a given Immersion frequency were tested. The highest results were obtained in the 2.8 multiplication coefficient with 20 ml culture medium volume and 3.2 using a density of 40 explants/flask. When the Temporal Immersion System is used with these results, a more efficient method for cassava micropropagation is established and also higher quality vitroplants for the rooting stage and further acclimatization in field conditions are produced. Key Words: Tissue Culture, liquid culture medium, Manihot esculenta Crantz

  5. Energy density and velocity of electromagnetic waves in lossy chiral medium

    International Nuclear Information System (INIS)

    Vorobyev, O B

    2014-01-01

    The average energy density of the macroscopic quasimonochromatic electromagnetic field U ts (t,r) in a linear passive chiral lossy medium described by the constitutive E–H relations is determined using a microscopic model. According to the model, U ts (t,r) is equal to the sum of the average energy densities of the electromagnetic field in free space U t0 (t,r) and electromagnetic oscillations in structural elements U s (t,r) induced by the electromagnetic wave. Making use of the Poynting theorem, the energy density U ts (t,r)≥U t0 (t,r) and power density of losses are derived as functions of the Poynting vector, polarization of the electromagnetic waves, phase shift between the field vectors and refractive index of a chiral medium. The exact energy velocity of the quasimonochromatic electromagnetic waves satisfying relativistic causality is determined using U ts (t,r). The approximate energy velocities of the quasimonochromatic electromagnetic wave are determined using energy density components approximating U ts (t,r) (e.g., the sum of the positive energy densities of the macroscopic electric and magnetic fields as well as the energy density of magnetoelectric cross-coupling). Comparison of the exact and approximate energy velocities with the group velocity in the case of a chiral lossy medium with a single-resonant frequency clarifies the concept of the electromagnetic energy and demonstrates the fundamental significance of the exact energy velocity. (paper)

  6. Individual demands of human embryos on IVF culture medium: influence on blastocyst development and pregnancy outcome.

    Science.gov (United States)

    Wirleitner, B; Vanderzwalmen, P; Stecher, A; Zech, M H; Zintz, M; Zech, N H

    2010-12-01

    The elucidation of the metabolic requirements of human embryos in vivo or in vitro remains, despite being intensively investigated, a work in progress. The adoption of extended embryo culture to the blastocyst stage during the last decade has entailed new challenges. With the increased attention to culture media formulations, more evidence on the sensitivity of embryos to their early environmental conditions is accumulating which might affect phenotype and developmental potential. A retrospective study was conducted that comprised 286 IVF cycles to evaluate the effect of two different culture media on blastocyst development and pregnancy outcome. Embryos were either cultured in a one step or a sequential medium. Higher fertilization rates and augmented blastocyst rates as well as higher implantation rates were observed when embryos were cultured in one step medium (Pcultured in either medium resulted in a significantly higher rate of twin pregnancies. Although multiple pregnancies should be avoided in assisted reproduction treatment to reduce risks for offspring and mother, this higher frequency of twin pregnancies resulting from the transfer of embryos derived from different culture media suggests that each embryo makes individual demands on its early environment. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  7. Discrete frequency slice wavelet transform

    Science.gov (United States)

    Yan, Zhonghong; Tao, Ting; Jiang, Zhongwei; Wang, Haibin

    2017-11-01

    This paper introduces a new kind of Time-Frequency Representation (TFR) method called Discrete Frequency Slice Wavelet Transform (DFSWT). It is an improved version of Frequency Slice Wavelet Transform (FSWT). The previous researches on FSWT show that it is a new efficient TFR in an easy way without strict limitation as traditional wavelet theory. DFSWT as well as FSWT are defined directly in frequency domain, and still keep its properties in time-frequency domain as FSWT decomposition, reconstruction and filter design, etc. However, the original signal is decomposed and reconstructed on a Chosen Frequency Domains (CFD) as need of application. CFD means that the decomposition and reconstruction are not completed on all frequency components. At first, it is important to discuss the necessary condition of CFD to reconstruct the original signal. And then based on norm l2, an optimization algorithm is introduced to reconstruct the original signal even accurately. Finally, for a test example, the TFR analysis of a real life signal is shown. Some conclusions are drawn that the concept of CFD is very useful to application, and the DFSWT can become a simple and easy tool of TFR method, and also provide a new idea of low speed sampling of high frequency signal in applications.

  8. Low-frequency-noise complaints

    DEFF Research Database (Denmark)

    Pedersen, Christian Sejer; Møller, Henrik; Persson-Waye, Kerstin

    2008-01-01

    From 203 cases of low-frequency complaints a random selection of twenty-one cases were investigated. The main aim of the investigation was to answer the question whether the annoyance is caused by an external physical sound or by a physically non-existing sound, i.e. low-frequency tinnitus. Noise...... of the complainants are annoyed by a physical sound (20-180 Hz), while others suffer from low-frequency tinnitus (perceived frequency 40-100 Hz). Physical sound at frequencies below 20 Hz (infrasound) is not responsible for the annoyance - or at all audible - in any of the investigated cases, and none...... of the complainants has extraordinary hearing sensitivity at low frequencies. For comparable cases of low-frequency noise complaints in general, it is anticipated that physical sound is responsible in a substantial part of the cases, while low-frequency tinnitus is responsible in another substantial part of the cases....

  9. Low frequency electromagnetic field sensor

    International Nuclear Information System (INIS)

    Zhu Min; Zhou Yan; He Yicheng; Zheng Zhenxing; Liu Sunkun

    2000-01-01

    The measurement technique of low frequency electromagnetic field is reported. According to this principle, the authors have designed a sensor, which is used to measure the natural electromagnetic field, SLEMP and electromagnetic signals generated by some explosions. The frequency band of this sensor is from 0.08 Hz to 2 MHz

  10. Lexical Frequency in Sign Languages

    Science.gov (United States)

    Johnston, Trevor

    2012-01-01

    Measures of lexical frequency presuppose the existence of corpora, but true machine-readable corpora of sign languages (SLs) are only now being created. Lexical frequency ratings for SLs are needed because there has been a heavy reliance on the interpretation of results of psycholinguistic and neurolinguistic experiments in the SL research…

  11. Gaming Frequency and Academic Performance

    Science.gov (United States)

    Ip, Barry; Jacobs, Gabriel; Watkins, Alan

    2008-01-01

    There are numerous claims that playing computer and video games may be educationally beneficial, but there has been little formal investigation into whether or not the frequency of exposure to such games actually affects academic performance. This paper explores the issue by analysing the relationships between gaming frequency--measured as the…

  12. Micronuclei Frequency in Radiation Worker

    International Nuclear Information System (INIS)

    Sudprasert, Wanwisa; Jungtanasombut, Amornrat; Pakkong, Pannee

    2009-07-01

    Full text: The purpose of this study is to determine the micronuclei (MN) frequency in peripheral blood lymphocytes of 31 individuals occupationally exposed to radiation compared to 24 controls. The effect of donor gender, age, alcoholic consumption, tea/coffee consumption and radiation burden on MN frequency was studied. The results showed that MN frequencies observed for exposed employees were significantly higher than in controls (p = 0.000). The average MN frequency in control was 39.1 ± 3.7 MN/1000 BN while those of exposed group were 60.9 ± 12.3, 61.6 ± 13.0 and 62.6 ± 11.8 MN/1000 BN for the range of accumulative doses at 0.01-3.00, 3.01-6.00 and 6.01-9.00 mSv, respectively. Moreover, MN frequency showed a positive trend with increased accumulative doses as a linear-quadratic relation (R 2 = 0.4754). No correlation of MN frequency with gender, age and alcoholic consumption could be observed in both exposed and control groups. However, the effect of tea/coffee consumption on MN frequency was clearly observed in the exposed individuals (t-test = -2.018, sig. (2-tailed) = 0.030). These results indicate that the increased MN frequency, an indicator of chromosomal aberration, is associated with occupational exposure to low doses of ionizing radiation

  13. Effectiveness of Medium Chain Triglyceride Ketogenic Diet in Thai Children with Intractable Epilepsy.

    Science.gov (United States)

    Chomtho, Krisnachai; Suteerojntrakool, Orapa; Chomtho, Sirinuch

    2016-02-01

    To determine the efficacy, side effects and feasibility of Medium chain triglyceride (MCT) ketogenic diet (KD) in Thai children with intractable epilepsy. Children with intractable epilepsy were recruited. Baseline seizure frequency was recorded over 4 weeks before starting MCT KD. Average seizure frequency was assessed at 1 month and 3 months, compared to the baseline using Wilcoxon Signed Rank Test. Side effects and feasibility were also assessed by blood tests and an interview. Sixteen subjects were recruited with mean seizure frequency of 0.35-52.5 per day. After treatment, there was a significant reduction in seizure frequency, ranging from 12% to 100% (p = 0.002 at 1 month, and 0.001 at 3 months). 64.3% of the subjects achieved more than 50% seizure reduction at 3 months and 28.6% of the patients were seizure-free. Common adverse effects were initial weight loss (37.5%) and nausea (25%). 87.5% of subjects and parents were satisfied with the MCT KD with 2 cases dropping-out due to diarrhea and non-compliance. MCT ketogenic diet is effective and feasible in Thai children with intractable epilepsy. Despite modification against Asian culinary culture, the tolerability and maintenance rate was still satisfactory. A larger study is required.

  14. Initial-value problem for the 1-D wave equation in an inhomogeneous medium

    International Nuclear Information System (INIS)

    Sedlacek, Z.; Roberts, B.; Adam, J.A.

    1986-03-01

    A complete mathematical analysis of oscillations of an inhomogeneous medium described by a wave equation with a space-dependent coefficient is given. The initial-value problem is solved both by the Laplace transform and by normal-mode analysis and the equivalency of both approaches is demonstrated. The Green function of the problem is a double-valued function of the complex frequency, analytic in the upper and lower halves of the complex frequency plane (the ''physical'' sheet of its Riemann surface) with discontinuity on the whole real axis, corresponding to the continuous frequency spectrum of the physical system in question. The Green function has complex poles on analytic continuation onto the ''unphysical'' sheet of its Riemann surface. This makes it possible, by inverting the Laplace transform, to interpret the solution of the initial-value problem in terms of ''damped'' eigenmodes. The continuum eigenmodes can be constructed directly and are also recovered by integrating the Green function in the complex frequency plane along a closed contour enclosing the spectrum. Their orthogonality and completeness is proved. The solution of the initial-value problem synthesized from the continuum eigenmodes can be interpreted in terms of travelling disturbances scattered by inhomogeneity. (author)

  15. Deep-subwavelength Decoupling for MIMO Antennas in Mobile Handsets with Singular Medium.

    Science.gov (United States)

    Xu, Su; Zhang, Ming; Wen, Huailin; Wang, Jun

    2017-09-22

    Decreasing the mutual coupling between Multi-input Multi-output (MIMO) antenna elements in a mobile handset and achieving a high data rate is a challenging topic as the 5 th -generation (5G) communication age is coming. Conventional decoupling components for MIMO antennas have to be re-designed when the geometries or frequencies of antennas have any adjustment. In this paper, we report a novel metamaterial-based decoupling strategy for MIMO antennas in mobile handsets with wide applicability. The decoupling component is made of subwavelength metal/air layers, which can be treated as singular medium over a broad frequency band. The flexible applicable property of the decoupling strategy is verified with different antennas over different frequency bands with the same metamaterial decoupling element. Finally, 1/100-wavelength 10-dB isolation is demonstrated for a 24-element MIMO antenna in mobile handsets over the frequency band from 4.55 to 4.75 GHz.

  16. Improvement of Laser Frequency Stabilization for the Optical Pumping Cesium Beam Standard

    International Nuclear Information System (INIS)

    Wang Qing; Duan Jun; Qi Xiang-Hui; Zhang Yin; Chen Xu-Zong

    2015-01-01

    A method is presented to improve the laser frequency stabilization for the optical pumping cesium clock. By comparing the laser frequency stabilization of different schemes, we verify that the light angle is an important factor that limits the long-term frequency stability. We minimize the drift of the light angle by using a fiber-coupled output, and lock the frequency of a distributed-feedback diode laser to the fluorescence spectrum of the atomic beam. The measured frequency stability is about 3.5 × 10 −11 at 1 s and reaches 1.5 × 10 −12 at 2000 s. The Allan variance keeps going down for up to thousands of seconds, indicating that the medium- and long-term stability of the laser frequency is significantly improved and perfectly fulfills the requirement for the optical pumping cesium clock. (paper)

  17. Impact of luminescence quenching on relaxation-oscillation frequency in solid-state lasers

    NARCIS (Netherlands)

    Agazzi, L.; Bernhardi, Edward; Worhoff, Kerstin; Pollnau, Markus

    Measurement of the laser relaxation-oscillation frequency as a function of pump rate allows one to determine parameters of the laser medium or cavity. We show that luminescence quenching of a fraction of the rare-earth ions in a solid-state laser affects the relaxation oscillations, resulting in

  18. New rules governing synaptic plasticity in core nucleus accumbens medium spiny neurons.

    Science.gov (United States)

    Ji, Xincai; Martin, Gilles E

    2012-12-01

    The nucleus accumbens is a forebrain region responsible for drug reward and goal-directed behaviors. It has long been believed that drugs of abuse exert their addictive properties on behavior by altering the strength of synaptic communication over long periods of time. To date, attempts at understanding the relationship between drugs of abuse and synaptic plasticity have relied on the high-frequency long-term potentiation model of T.V. Bliss & T. Lømo [(1973) Journal of Physiology, 232, 331-356]. We examined synaptic plasticity using spike-timing-dependent plasticity, a stimulation paradigm that reflects more closely the in vivo firing patterns of mouse core nucleus accumbens medium spiny neurons and their afferents. In contrast to other brain regions, the same stimulation paradigm evoked bidirectional long-term plasticity. The magnitude of spike-timing-dependent long-term potentiation (tLTP) changed with the delay between action potentials and excitatory post-synaptic potentials, and frequency, whereas that of spike-timing-dependent long-term depression (tLTD) remained unchanged. We showed that tLTP depended on N-methyl-d-aspartate receptors, whereas tLTD relied on action potentials. Importantly, the intracellular calcium signaling pathways mobilised during tLTP and tLTD were different. Thus, calcium-induced calcium release underlies tLTD but not tLTP. Finally, we found that the firing pattern of a subset of medium spiny neurons was strongly inhibited by dopamine receptor agonists. Surprisingly, these neurons were exclusively associated with tLTP but not with tLTD. Taken together, these data point to the existence of two subgroups of medium spiny neurons with distinct properties, each displaying unique abilities to undergo synaptic plasticity. © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  19. Optimal Frequency Ranges for Sub-Microsecond Precision Pulsar Timing

    Science.gov (United States)

    Lam, Michael Timothy; McLaughlin, Maura; Cordes, James; Chatterjee, Shami; Lazio, Joseph

    2018-01-01

    Precision pulsar timing requires optimization against measurement errors and astrophysical variance from the neutron stars themselves and the interstellar medium. We investigate optimization of arrival time precision as a function of radio frequency and bandwidth. We find that increases in bandwidth that reduce the contribution from receiver noise are countered by the strong chromatic dependence of interstellar effects and intrinsic pulse-profile evolution. The resulting optimal frequency range is therefore telescope and pulsar dependent. We demonstrate the results for five pulsars included in current pulsar timing arrays and determine that they are not optimally observed at current center frequencies. We also find that arrival-time precision can be improved by increases in total bandwidth. Wideband receivers centered at high frequencies can reduce required overall integration times and provide significant improvements in arrival time uncertainty by a factor of $\\sim$$\\sqrt{2}$ in most cases, assuming a fixed integration time. We also discuss how timing programs can be extended to pulsars with larger dispersion measures through the use of higher-frequency observations.

  20. A frequency tracking synthesizer for beam diagnostic systems

    International Nuclear Information System (INIS)

    Peterson, D.; Marriner, J.

    1991-01-01

    In low and medium energy synchrotrons the beam revolution frequency changes by a large factor during the acceleration process. High production rates require that these machines cycle rapidly. In attempting to diagnose instabilities which develop during the acceleration process it is useful to be able to select some frequency segment between revolution harmonics for viewing. Most types of test equipment operating in the frequency domain, such as spectrum analyzers and network analyzers, are not suited to making direct measurements on such rapidly sweeping signals. Ideally, one would want to set the frequency frame of reference to the spot in the accelerating revolution harmonic domain where the measurements are to be made. A scheme using a direct digital synthesizer (DDS) was developed to provide this moving reference frame. This paper describes a synthesizer scheme combining digital and analog synthesizer techniques to allow tracking of signals during acceleration. Virtually any ratio of synthesizer to beam revolution frequency may be generated by this scheme. Details of hardware and measurement results are presented

  1. The Quiet Rise of Medium-Scale Farms in Malawi

    Directory of Open Access Journals (Sweden)

    Ward Anseeuw

    2016-06-01

    Full Text Available Medium-scale farms have become a major force in Malawi’s agricultural sector. Malawi’s most recent official agricultural survey indicates that these account for over a quarter of all land under cultivation in Malawi. This study explores the causes and multifaceted consequences of the rising importance of medium-scale farms in Malawi. We identify the characteristics and pathways of entry into farming based on surveys of 300 medium-scale farmers undertaken in 2014 in the districts of Mchinji, Kasungu and Lilongwe. The area of land acquired by medium-scale farmers in these three districts is found to have almost doubled between 2000 and 2015. Just over half of the medium-scale farmers represent cases of successful expansion out of small-scale farming status; the other significant proportion of medium-scale farmers are found to be urban-based professionals, entrepreneurs and/or civil servants who acquired land, some very recently, and started farming in mid-life. We also find that a significant portion of the land acquired by medium-scale farmers was utilized by others prior to acquisition, that most of the acquired land was under customary tenure, and that the current owners were often successful in transferring the ownership structure of the acquired land to a long-term leaseholding with a title deed. The study finds that, instead of just strong endogenous growth of small-scale famers as a route for the emergence of medium-scale farms, significant farm consolidation is occurring through land acquisitions, often by urban-based people. The effects of farmland acquisitions by domestic investors on the country’s primary development goals, such as food security, poverty reduction and employment, are not yet clear, though some trends appear to be emerging. We consider future research questions that may more fully shed light on the implications of policies that would continue to promote land acquisitions by medium-scale farms.

  2. Boolean Differentiation Equations Applicable in Reconfigurable Computational Medium

    Directory of Open Access Journals (Sweden)

    Shidlovskiy Stanislav

    2016-01-01

    Full Text Available High performance computing environment synthesis with parallel architecture reconstructing throughout the process itself is described. Synthesized computational medium involving Boolean differential equation calculations so as to function in real-time image processing. Automaton imaging was illustrated involving the rearrangement of every processing medium element to calculate the partial differentials of n-th order in respect to Boolean function variables. The method of obtaining setting codes for each element was also described. An example in calculating 2nd -order Boolean derivative to two differentials in respect to Boolean functions, depending on three arguments within the reconstructible computational medium of 8×8 processing elements was given.

  3. Organic chemistry and biology of the interstellar medium

    Science.gov (United States)

    Sagan, C.

    1973-01-01

    Interstellar organic chemistry is discussed as the field of study emerging from the discovery of microwave lines of formaldehyde and of hydrogen cyanide in the interstellar medium. The reliability of molecular identifications and comparisons of interstellar and cometary compounds are considered, along with the degradational origin of simple organics. It is pointed out that the contribution of interstellar organic chemistry to problems in biology is not substantive but analogical. The interstellar medium reveals the operation of chemical processes which, on earth and perhaps on vast numbers of planets throughout the universe, led to the origin of life, but the actual molecules of the interstellar medium are unlikely to play any significant biological role.

  4. Acoustic characteristics of the medium with gradient change of impedance

    Science.gov (United States)

    Hu, Bo; Yang, Desen; Sun, Yu; Shi, Jie; Shi, Shengguo; Zhang, Haoyang

    2015-10-01

    The medium with gradient change of acoustic impedance is a new acoustic structure which developed from multiple layer structures. In this paper, the inclusion is introduced and a new set of equations is developed. It can obtain better acoustic properties based on the medium with gradient change of acoustic impedance. Theoretical formulation has been systematically addressed which demonstrates how the idea of utilizing this method. The sound reflection and absorption coefficients were obtained. At last, the validity and the correctness of this method are assessed by simulations. The results show that appropriate design of parameters of the medium can improve underwater acoustic properties.

  5. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    2015-01-01

    by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME......This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...

  6. Prevalence of carriers of the most common medium-chain acyl-CoA dehydrogenase (MCAD) deficiency mutation (G985A) in the Netherlands

    NARCIS (Netherlands)

    de Vries, H G; Niezen-Koning, K; Kliphuis, J W; Smit, G P; Scheffer, H; ten Kate, L P

    The G985A mutation represents about 90% of all medium-chain acyl-CoA dehydrogenase (MCAD) allele mutations that cause the clinical symptoms of MCAD deficiency. The prevalence of carriers varies between different European populations, with high frequencies in the northwestern part of Europe. To

  7. Alteration of interferential current and transcutaneous electrical nerve stimulation frequency: effects on nerve excitation.

    Science.gov (United States)

    Palmer, S T; Martin, D J; Steedman, W M; Ravey, J

    1999-09-01

    To investigate the effects of different interferential current (IC) and transcutaneous electrical nerve stimulation (TENS) frequencies on sensory, motor, and pain thresholds. Single blind, repeated measures design. Laboratory. Women students 18 to 30 years old (n = 24). Premodulated IC and square-wave TENS pulses (125micros phase duration) were applied over the median nerve at a range of frequencies in all subjects. The peak current (in milliamperes) was recorded twice at each threshold for each frequency, and averaged. Both IC and TENS displayed a statistically significant effect of frequency for each threshold. However, frequency effects with IC were not well defined and were of small magnitude. Pure 4kHz current (0Hz amplitude modulated frequency) with IC did not produce effects different from those produced when an amplitude modulated frequency was included. With TENS, frequency effects were very clearly observed, with a distinct increase in the current intensity at each threshold as frequency decreased. It is postulated that the medium frequency component of IC is the main parameter in stimulation, contrary to traditional claims of the amplitude modulated frequency being important. TENS was shown to be a more adaptable method of stimulating these nerve pathways than IC.

  8. Engineering the Frequency Spectrum of Bright Squeezed Vacuum via Group Velocity Dispersion in an SU(1,1) Interferometer.

    Science.gov (United States)

    Lemieux, Samuel; Manceau, Mathieu; Sharapova, Polina R; Tikhonova, Olga V; Boyd, Robert W; Leuchs, Gerd; Chekhova, Maria V

    2016-10-28

    Bright squeezed vacuum, a promising tool for quantum information, can be generated by high-gain parametric down-conversion. However, its frequency and angular spectra are typically quite broad, which is undesirable for applications requiring single-mode radiation. We tailor the frequency spectrum of high-gain parametric down-conversion using an SU(1,1) interferometer consisting of two nonlinear crystals with a dispersive medium separating them. The dispersive medium allows us to select a narrow band of the frequency spectrum to be exponentially amplified by high-gain parametric amplification. The frequency spectrum is thereby narrowed from (56.5±0.1) to (1.22±0.02)  THz and, in doing so, the number of frequency modes is reduced from approximately 50 to 1.82±0.02. Moreover, this method provides control and flexibility over the spectrum of the generated light through the timing of the pump.

  9. Heating systems with PLC and frequency control

    Energy Technology Data Exchange (ETDEWEB)

    Abdallah, Salah; Abu-Mallouh, Riyad [Department of Mechanical and Industrial Engineering, Applied Science University, Amman 11931 (Jordan)

    2008-11-15

    In this work, medium capacity controlled heating system is designed and constructed. The programming method of control of heating process is achieved by means of integrated programmable logic controller (PLC) and frequency inverter (FI). The PLC main function is to determine the required temperatures levels and the related time intervals of the heating hold time in the furnace. FI is used to control the dynamic change of temperature between various operating points. The designed system shows the capability for full control of temperature from zero to maximum for any required range of time in case of increasing or decreasing the temperature. All variables of the system will be changed gradually until reaching their needed working points. An experimental study was performed to investigate the effect of tempering temperature and tempering time on hardness and fatigue resistance of 0.4% carbon steel. It was found that increasing tempering temperature above 550 C or tempering time decreases the hardness of the material. It was also found that there is a maximum number of cycles to which the specimen can survive what ever the applied load was. (author)

  10. Heating systems with PLC and frequency control

    International Nuclear Information System (INIS)

    Abdallah, Salah; Abu-Mallouh, Riyad

    2008-01-01

    In this work, medium capacity controlled heating system is designed and constructed. The programming method of control of heating process is achieved by means of integrated programmable logic controller (PLC) and frequency inverter (FI). The PLC main function is to determine the required temperatures levels and the related time intervals of the heating hold time in the furnace. FI is used to control the dynamic change of temperature between various operating points. The designed system shows the capability for full control of temperature from zero to maximum for any required range of time in case of increasing or decreasing the temperature. All variables of the system will be changed gradually until reaching their needed working points. An experimental study was performed to investigate the effect of tempering temperature and tempering time on hardness and fatigue resistance of 0.4% carbon steel. It was found that increasing tempering temperature above 550 deg. C or tempering time decreases the hardness of the material. It was also found that there is a maximum number of cycles to which the specimen can survive what ever the applied load was

  11. High Frequency Electronic Packaging Technology

    Science.gov (United States)

    Herman, M.; Lowry, L.; Lee, K.; Kolawa, E.; Tulintseff, A.; Shalkhauser, K.; Whitaker, J.; Piket-May, M.

    1994-01-01

    Commercial and government communication, radar, and information systems face the challenge of cost and mass reduction via the application of advanced packaging technology. A majority of both government and industry support has been focused on low frequency digital electronics.

  12. Global Multihazard Frequency and Distribution

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Multihazard Frequency and Distribution is a 2.5 minute grid presenting a simple multihazard index based solely on summated single-hazard decile values. The...

  13. Geographies of High Frequency Trading

    DEFF Research Database (Denmark)

    Grindsted, Thomas Skou

    2016-01-01

    This paper investigates the geographies of high frequency trading. Today shares shift hands within micro seconds, giving rise to a form of financial geographies termed algorithmic capitalism. This notion refers to the different spatio-temporalities produced by high frequency trading, under...... the valuation of time. As high frequency trading accelerates financial markets, the paper examines the spatio-temporalities of automated trading by the ways in which the speed of knowledge exploitation in financial markets is not only of interest, but also the expansion between different temporalities....... The paper demonstrates how the intensification of time-space compression produces radical new dynamics in the financial market and develops information rent in HFT as convertible to a time rent and a spatio-temporal rent. The final section discusses whether high frequency trading only responds to crises...

  14. Medium Range Forecast (MRF) and Nested Grid Model (NGM)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Nested Grid Model (NGM) and Medium Range Forecast (MRF) Archive is historical digital data set DSI-6140, archived at the NOAA National Centers for Environmental...

  15. Fem Formulation of Heat Transfer in Cylindrical Porous Medium

    Science.gov (United States)

    Azeem; Khaleed, H. M. T.; Soudagar, Manzoor Elahi M.

    2017-08-01

    Heat transfer in porous medium can be derived from the fundamental laws of flow in porous region ass given by Henry Darcy. The fluid flow and energy transport inside the porous medium can be described with the help of momentum and energy equations. The heat transfer in cylindrical porous medium differs from its counterpart in radial and axial coordinates. The present work is focused to discuss the finite element formulation of heat transfer in cylindrical porous medium. The basic partial differential equations are derived using Darcy law which is the converted into a set of algebraic equations with the help of finite element method. The resulting equations are solved by matrix method for two solution variables involved in the coupled equations.

  16. Electromagnetic radiation of ultrarelativistic particles at scattering in excited medium

    International Nuclear Information System (INIS)

    Malyshevskij, V.S.

    1990-01-01

    The interaction between relativistic particles and a gaseous or condensed medium with a high density of nondegenerate excited quantum states involves the coherent conversion of atomic or molecular excitations into electromagnetic radiation

  17. Solitons in a Dielectric Medium under an External Magnetic Field

    OpenAIRE

    Isamu, NAKATA; Hiroaki, ONO; Mitito, YOSIDA; College of Integrated Arts and Sciences, University of Osaka Prefecture; Department of Mathematics and Physics, Faculty of Engineering, Setunan University; Nippondenso Co., Ltd.

    1993-01-01

    Solitons in a dielectric medium propagating along an external magnetic field is investigated. By means of a nonlinear perturbation method, the derivative nonlinear Schrodinger equation is derived and the possibility of propagation of the spiky and algebraic solitons is shown.

  18. RSW Fully Tet Medium Cell-Centered Mesh

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the RSW Fully tetrahedral medium cell-centered unstructured grid with a viscous wall. UG3 : Grid File Name = rsw_med_tetcc.b8.ugrid UG3 : Quad Surface Faces=...

  19. RSW Mixed Element Cell-Centered Medium Mesh

    Data.gov (United States)

    National Aeronautics and Space Administration — This RSW gridset is designed as the medium size mixed element grid for use with cell-centered unstructured meshes. UG3 : Grid File Name = rsw_med_mixedcc.b8.ugrid...

  20. On Emulation of Flueric Devices in Excitable Chemical Medium.

    Directory of Open Access Journals (Sweden)

    Andrew Adamatzky

    Full Text Available Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.

  1. Effect of Instructional Medium on Students' Performance: A ...

    African Journals Online (AJOL)

    Effect of Instructional Medium on Students' Performance: A Comparison of Reading and Oral Instruction in Nigeria. Katrina A. Korb, Binfa Kelvin Gono, Samuel Adekunle Jinadu, Abangom Ruth John, Gabriel N. Mwoltu, Rimdan Nanle Oona ...

  2. Space Power Theory: Controlling the Medium Without Weapons in Space

    National Research Council Canada - National Science Library

    Wilkerson, Don L

    2008-01-01

    ...) Modern theorists suggest today's military is poised to develop a space power theory, similar to Gorbett's sea power theory, that is relevant in the exploitation of the space medium The challenges...

  3. Modification of Einstein A Coefficient in Dissipative Gas Medium

    Science.gov (United States)

    Cao, Chang-Qi; Cao, Hui; Qin, Ke-Cheng

    1996-01-01

    Spontaneous radiation in dissipative gas medium such as plasmas is investigated by Langevin equations and the modified Weisskopf-Wigner approximation. Since the refractive index of gas medium is expected to be nearly unity, we shall first neglect the medium polarization effect. We show that absorption in plasmas may in certain case modify the Einstein A coefficient significantly and cause a pit in the A coefficient-density curves for relatively low temperature plasmas and also a pit in the A coefficient-temperature curves. In the next, the effect of medium polarization is taken into account in addition. To our surprise, its effect in certain case is quite significant. The dispersive curves show different behaviors in different region of parameters.

  4. Theoretical Investigation of Trust in Small and Medium Sized Enterprises

    Directory of Open Access Journals (Sweden)

    Valentinas Navickas

    2014-06-01

    Full Text Available The hectic pace of competition pushes the sector of small and medium enterprise to adopt sophisticated marketing ideas. In this context, customers are becoming more and more selective. However, expansion possibilities are burdened by the great variety of limitations. The current study paper aims to investigate the academic perception of trust which is treated as competitive advantage for small and medium enterprises. The object of the article is trust in small and medium enterprises. It has three objectives: to analyse small and medium enterprise characteristics through the academic perspective; to consider trust from the theoretical point of view; and to present the models that centre their attention on the trust as a construct that enhances customer satisfaction. Regarding the novelty of the current study, it brings a novel approach on a great variety of collected understandings of trust and puts an important foundation for future theory and practice investigations.

  5. Medium resolution image fusion, does it enhance forest structure assessment

    CSIR Research Space (South Africa)

    Roberts, JW

    2008-07-01

    Full Text Available This research explored the potential benefits of fusing optical and Synthetic Aperture Radar (SAR) medium resolution satellite-borne sensor data for forest structural assessment. Image fusion was applied as a means of retaining disparate data...

  6. Fine coal processing with dense-medium cyclones

    CSIR Research Space (South Africa)

    De Korte, GJ

    2012-10-01

    Full Text Available . The paper provides a brief overview of past and current application of dense medium cyclones in the processing of fine coal and reviews some of the important considerations for the successful application of the technique....

  7. Two-dimensional static deformation of an anisotropic medium

    Indian Academy of Sciences (India)

    1989). Chou (1976) and Ting (1995) discussed antiplane strain deformation of an anisotropic medium. Garg et al (1996) obtained representations of seismic sources causing antiplane strain deformations of orthotropic media. The corresponding ...

  8. Correlation of Two Coupled Particles in Viscoelastic Medium

    International Nuclear Information System (INIS)

    Xie Baisong; Wu Haicheng; Yan Shiwei; Zhang Fengshou; Dulat, Sayipjamal

    2006-01-01

    Considering the viscoelastic memory effect, we study the correlated motion of two hydrodynamically coupled colloidal particles, each of which confined in a harmonic potential well, in a Kelvin-type and Maxwell-type viscoelastic medium. We find that viscoelastic relaxation plays a significant role in modifying the correlation, particularly the cross correlation. We also find that both the real and imaginary parts of the response function are significantly different from the viscous medium case. In particular there is a phase shift between the vanishing imaginary part and the maximal real part of the response function in a viscoelastic medium. In addition imaginary part of the cross correlation response function exhibits a net energy loss (gain) behavior when the elasticity parameter of the medium is larger (smaller) than the critical value for Kelvin (Maxwell) viscoelastic fluid. Some implication of our results and their connection with previous works are discussed.

  9. Defining Small and Medium Enterprises: a critical review

    Directory of Open Access Journals (Sweden)

    Gentrit Berisha

    2015-03-01

    Full Text Available The OECD estimates that small and medium enterprises account for 90% of firms and employ 63% of the workforce in the world (Munro: 2013. Small and medium enterprises account for that amount of businesses thatit is senseless the arbitrariness with which they are defined. Language mainly used for definition is numbers, but it is difficult to find two institutions, statistical agencies or countries who speak the same language in terms of small and medium enterprises. Academics, authors, policy makers apply SMEdefinitions in terms of dichotomy between universality and standardization of a unique definition and relativity and sectored specialization. Although qualitative criteria-characteristics of SMEs easily distinguish them from large businesses, quantitative criteria are mainlyused for their dimensional classification. This paper deals with a critical approachto the definition of small and medium enterprises, inconsistencies in criteria and various proposed approaches to the definition towards universal acceptance.

  10. Bound values for Hall conductivity of heterogeneous medium under ...

    Indian Academy of Sciences (India)

    - ditions in inhomogeneous medium has been studied. It is shown that bound values for. Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect ...

  11. Compact Low Frequency Radio Antenna

    Science.gov (United States)

    Punnoose, Ratish J.

    2008-11-11

    An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

  12. Radio Frequency Signal Propagation Study

    Science.gov (United States)

    2014-02-01

    and software solutions UNCLASSIFIED 5 UNCLASSIFIED DSTO-TR-2868 number of variables to select including the waveform used and whether the platform...the road. Transmission licences for the following five frequencies were obtained, 1216, 1270, 1399, 1525 and 1650 MHz. These frequencies were...Institution of Electrical Engineers, 2000 7. Matlab Software Package QPEM, Written by Richard Hawkes, APNT Group, CEWD, DSTO 8. Parsons, JD

  13. Lossless equalization of frequency combs

    OpenAIRE

    Torres Company, Víctor; Lancis Sáez, Jesús; Andrés, Pedro

    2008-01-01

    Frequency combs obtained by sinusoidal phase modulation of narrow-band continuous-wave lasers are widely used in the field of optical communications. However, the resulting spectral envelope of the comb is not at. In this Letter, we propose a general and eficient approach to achieve at frequency combs with tunable bandwidth. The idea is based on a two-step process. First, eficient generation of a train with temporal at-top-pulse profile is required. Second, we use larg...

  14. Gaming frequency and academic performance

    OpenAIRE

    Ip, Barry; Jacobs, Gabriel; Watkins, Alan

    2008-01-01

    There are numerous claims that playing computer and video games may be educationally beneficial, but there has been little formal investigation into whether or not the frequency of exposure to such games actually affects academic performance. This paper explores the issue by analysing the relationships between gaming frequency –measured as the amount of time undergraduate students spend playing games in their free time – and their academic performance as measured by their examination marks. U...

  15. Chromosomal aberration frequency in lymphocytes predicts the risk of cancer

    DEFF Research Database (Denmark)

    Bonassi, Stefano; Norppa, Hannu; Ceppi, Marcello

    2008-01-01

    for stomach cancer [RR(medium) = 1.17 (95% CI = 0.37-3.70), RR(high) = 3.13 (95% CI = 1.17-8.39)]. Exposure to carcinogens did not modify the effect of CA levels on overall cancer risk. These results reinforce the evidence of a link between CA frequency and cancer risk and provide novel information......Mechanistic evidence linking chromosomal aberration (CA) to early stages of cancer has been recently supported by the results of epidemiological studies that associated CA frequency in peripheral lymphocytes of healthy individuals to future cancer incidence. To overcome the limitations of single...... studies and to evaluate the strength of this association, a pooled analysis was carried out. The pooled database included 11 national cohorts and a total of 22 358 cancer-free individuals who underwent genetic screening with CA for biomonitoring purposes during 1965-2002 and were followed up for cancer...

  16. Scattering by closely spaced infinite cylinders in an absorbing medium

    Directory of Open Access Journals (Sweden)

    S.-C. Lee

    2011-09-01

    Full Text Available Scattering by closely spaced parallel infinite cylinders in an absorbing medium is considered in this paper. The source wave is arbitrarily polarized and propagates in a general direction at the cylinders. The formulation utilizes the Hertz potential approach, and the scattering cross section and intensity distribution in the far-field are developed. Numerical results are presented to illustrate the influence of the absorbing medium on the scattering properties of two configurations of closely-spaced cylinders.

  17. The growth of paracoccus halodenitrificans in a defined medium

    Science.gov (United States)

    Hochstein, L. I.; Tomlinson, G. A.

    1983-01-01

    A synthetic medium, consisting of inorganic salts and any of a number of carbon sources, supported the aerobic growth of Paracoccus halodenitrificans when supplemented with thiamine. The same medium plus a nitrogenous oxide supported anaerobic growth when additionally supplemented with methionine. The observation that vitamin B12 or betaine replaced methionine suggested that P. halodenitrificans had a defect in the cobalamin dependent pathway for methionine biosynthesis, as well as the inability to synthesize betaine when growing anaerobically.

  18. Quenching of g/sub A/ in the nuclear medium

    Energy Technology Data Exchange (ETDEWEB)

    Parthasarathy, R.; Pasupathy, J.

    1988-05-01

    The numerical values of g/sub A/ are evaluated using quantum-chromodynamic sum rules. The nuclear medium effects are taken into account by modifying the chiral symmetry breaking correlation, . Our results indicate a quenching of g/sub A/ in a nuclear medium. The physical reasons for this fundamental quenching are noted to be the same for the effective mass of the nucleon bound in a nucleus being less than its free space value.

  19. Hydrodynamic instability of compressible fluid in porous medium

    International Nuclear Information System (INIS)

    Argal, Shraddha; Tiwari, Anita; Sharma, P K; Prajapati, R P

    2014-01-01

    The hydrodynamic Rayleigh -Taylor instability of two superposed compressible fluids in porous medium has been studied. The dispersion relation is derived for such a medium by using normal mode analysis. The RT instability is discussed for various simplified configuration. The effect of porosity and dynamic viscosity has been analyzed and it is observed that porosity and dynamic viscosity have stabilizing effect on the Rayleigh- Taylor instability of compressible fluids.

  20. Risk analysis methodology designed for small and medium enterprises

    OpenAIRE

    Ladislav Beránek; Radim Remeš

    2009-01-01

    The aim of this paper is to present risk analysis procedures successfully applied by several Czech small and medium enterprises. The paper presents in detail the individual steps we use in risk analysis of small and medium enterprises in the Czech Republic. Suggested method to risk analysis is based on the modification of the FRAP methodology and the BITS recommendation. Modifications of both methodologies are described in detail. We propose modified risk analysis methodology which is quick a...