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Sample records for relaxation processes due

  1. Relaxation processes during amorphous metal alloys heating

    International Nuclear Information System (INIS)

    Malinochka, E.Ya.; Durachenko, A.M.; Borisov, V.T.

    1982-01-01

    Behaviour of Te+15 at.%Ge and Fe+13 at.%P+7 at.%C amorphous metal alloys during heating has been studied using the method of differential scanning calorimetry (DSC) as the most convenient one for determination of the value of heat effects, activation energies, temperature ranges of relaxation processes. Thermal effects corresponding to high-temperature relaxation processes taking place during amorphous metal alloys (AMA) heating are detected. The change of ratio of relaxation peaks values on DSC curves as a result of AMA heat treatment can be explained by the presence of a number of levels of inner energy in amorphous system, separated with potential barriers, the heights of which correspond to certain activation energies of relaxation processes

  2. Deference and Due Process

    OpenAIRE

    Vermeule, Cornelius Adrian

    2015-01-01

    In the textbooks, procedural due process is a strictly judicial enterprise; although substantive entitlements are created by legislative and executive action, it is for courts to decide independently what process the Constitution requires. The notion that procedural due process might be committed primarily to the discretion of the agencies themselves is almost entirely absent from the academic literature. The facts on the ground are very different. Thanks to converging strands of caselaw ...

  3. Capturing molecular multimode relaxation processes in excitable gases based on decomposition of acoustic relaxation spectra

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Wang, Shu; Zhang, Kesheng

    2017-08-01

    Existing two-frequency reconstructive methods can only capture primary (single) molecular relaxation processes in excitable gases. In this paper, we present a reconstructive method based on the novel decomposition of frequency-dependent acoustic relaxation spectra to capture the entire molecular multimode relaxation process. This decomposition of acoustic relaxation spectra is developed from the frequency-dependent effective specific heat, indicating that a multi-relaxation process is the sum of the interior single-relaxation processes. Based on this decomposition, we can reconstruct the entire multi-relaxation process by capturing the relaxation times and relaxation strengths of N interior single-relaxation processes, using the measurements of acoustic absorption and sound speed at 2N frequencies. Experimental data for the gas mixtures CO2-N2 and CO2-O2 validate our decomposition and reconstruction approach.

  4. Quantization by stochastic relaxation processes and supersymmetry

    International Nuclear Information System (INIS)

    Kirschner, R.

    1984-01-01

    We show the supersymmetry mechanism resposible for the quantization by stochastic relaxation processes and for the effective cancellation of the additional time dimension against the two Grassmann dimensions. We give a non-perturbative proof of the validity of this quantization procedure. (author)

  5. Impulsive relaxation process in MHD driven reconnection

    International Nuclear Information System (INIS)

    Kitabata, H.; Hayashi, T.; Sato, T.

    1997-01-01

    Compressible magnetohydrodynamic (MHD) simulation is carried out in order to investigate energy relaxation process of the driven magnetic reconnection in an open finite system through a long time calculation. It is found that a very impulsive energy release occurs in an intermittent fashion through magnetic reconnection for a continuous magnetic flux injection on the boundary. We focus our attention on the detailed process in the impulsive phase, which is the reconnection rate is remarkably enhanced up. (author)

  6. Interstitial relaxations due to hydrostatic stress in niobium--oxygen alloys

    International Nuclear Information System (INIS)

    Tewari, S.N.

    1974-01-01

    Experimental investigations of the anelastic relaxation induced by hydrostatic stress in the range from ambient to 81 ksi were made for niobium--oxygen alloys. The anelastic responses, both for the pressurization and the pressure release experiments, were followed by measuring the relative length change between the oxygenated niobium sample and a pure niobium frame with a precision of about 2 A. The relaxation spectrum observed was shown to be made up of three distinct relaxations with unique relaxation times and strengths. The pressure dependence of the relaxation times gave the apparent activation volume for these relaxations of the order of 4 cm 3 /mole. The relaxations were observed to have relaxation strengths of the order of 10 -4 which were found to be independent of pressure up to 81 ksi. The relaxation times for these relaxations were found to occur in the same general temperature range as those for the Snoek relaxations of oxygen clusters in niobium. The temperature dependence of the relaxation times, however, gave activation energies of about 11 to 15 kcal/mole, as compared with roughly 27 to 29 kcal/mole for the Snoek relaxation of oxygen clusters in niobium. Several possible models for these relaxations were developed, however, none could predict the observed temperature dependence. The best interpretation of the data is that due to some anomalous competing relaxation the actual temperature dependence of these relaxations could not be observed. A completely self-consistent analysis is found which is based upon this assumption. (U.S.)

  7. gamma. -relaxation process in crystallizable polymers

    Energy Technology Data Exchange (ETDEWEB)

    Mindiyarov, Kh G; Zelenev, Yu V; Bartenev, G M [Birskij Gosudarstvennyj Pedagogicheskij Inst. (USSR)

    1975-07-01

    In the present paper, with the aid of radiothermoluminescence technique ..gamma..-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to ..gamma..-rays of Co/sup 60/ at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the ..cap alpha.. - ..gamma..-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP ..cap alpha..-maximum may be absent. Dependence has been studied of the luminescence intensity in the ..cap alpha..- and ..gamma..-maxima (Isub(..cap alpha..)/Isub(..gamma..)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(..gamma..)re of crystallinity degree.

  8. Ferromagnetic resonance relaxation processes in Zn2Yt

    International Nuclear Information System (INIS)

    Mita, M.; Shimizu, H.

    1975-01-01

    Experimentally obtained linewidth in FMR of Zn 2 Y is analyzed numerically on the basis of two-magnon, three-magnon and four-magnon relaxation processes. In the analysis procedure of three-magnon linewidth, the effective exchange constants are determined to be D = 0.15 x 10 -9 Oe cm 2 and D = 9.3 x 10 -9 Oe cm 2 within and between the crystallographic planes. The two-magnon linewidth induced by surface imperfections is discussed in consideration of scattering due to multipole demagnetizations of the imperfections. The four-magnon linewidth is observed for the first time and analyzed successfully

  9. Models for multiple relaxation processes in collagen fiber

    Indian Academy of Sciences (India)

    ... originate from stress strain induced changes in hydrogen bond network whereas the other seems to be more strongly coupled to salt like bridges and electrostatic interactions. Urea alters the activation energy for one relaxation step while pH and solvent dielectric constant alter the relaxation behavior one set of processes.

  10. Relaxation Processes and Time Scale Transformation.

    Science.gov (United States)

    1982-03-01

    the response function may be immediately recognized as being 14 of the Kubo - Green type in the classical regime. Given this general framework, it is now...b as a function of temperature is 24 equivalent to the Vogel-Beuche-Fulcher empirical law for viscosity or the Williams-Landel-Ferry empirical law...relaxation times. With the weighted sum in the form of an integral , one can write exp(-(t/T)b ] = f dT’g(r’) exp[-(t/T’)], O

  11. Teacher Dismissal and Due Process.

    Science.gov (United States)

    Leichner, Edward C.; Blackstone, Sidney

    1977-01-01

    This article addresses due process requirements in the nonrenewal and dismissal of tenured and nontenured teachers. The Georgia Fair Dismissal Law is used as a basis for discussing the grounds for teacher dismissal. Dismissal grounds discussed are 1) incompetency; 2) insubordination; 3) willful neglect of duties; 4) immorality; 5) inciting,…

  12. Due Process Hearing Case Study

    Science.gov (United States)

    Bateman, David F.

    2009-01-01

    William is 9 years of age, residing with his parent within the boundaries of an unnamed district ("the District"). As a student with autism he is eligible for special education programming and services. There was one issue presented for this due process hearing: What was the appropriate program and placement for him for the 2008-2009 school year?…

  13. Spin relaxation in quantum dots due to electron exchange with leads.

    Science.gov (United States)

    Vorontsov, A B; Vavilov, M G

    2008-11-28

    We calculate spin relaxation rates in lateral quantum dot systems due to electron exchange between dots and leads. Using rate equations, we develop a theoretical description of the experimentally observed electric current in the spin blockade regime of double quantum dots. A single expression fits the entire current profile and describes the structure of both the conduction peaks and the suppressed ("valley") region. Extrinsic rates calculated here have to be taken into account for accurate extraction of intrinsic relaxation rates due to the spin-orbit and hyperfine spin scattering mechanisms from spin blockade measurements.

  14. A Block-Asynchronous Relaxation Method for Graphics Processing Units

    OpenAIRE

    Anzt, H.; Dongarra, J.; Heuveline, Vincent; Tomov, S.

    2011-01-01

    In this paper, we analyze the potential of asynchronous relaxation methods on Graphics Processing Units (GPUs). For this purpose, we developed a set of asynchronous iteration algorithms in CUDA and compared them with a parallel implementation of synchronous relaxation methods on CPU-based systems. For a set of test matrices taken from the University of Florida Matrix Collection we monitor the convergence behavior, the average iteration time and the total time-to-solution time. Analyzing the r...

  15. Temperature effects on loss of prestress due to relaxation of steel

    International Nuclear Information System (INIS)

    Appa Rao, G.; Yamini Sreevalli, I.; Meher Prasad, A.; Reddy, G.R.; Prabhakar, G.

    2007-01-01

    Prestressed concrete is used in general civil engineering applications and in nuclear power plants for a number of structures such as containments, reactor pressure vessels, missile shield members, reactor cavity walls etc. Loss of prestress in containment structures is a serious concern for the longevity rather than serviceability. Loss of prestress higher than the initially designed values has been reported by various agencies at a number of nuclear power plants with prestressed concrete containment structures. At present the codes specify the prestress losses in Nuclear Power Plant Containment (NPPC) structures for 50 years. However there is a continuous effort to improve the life of NPPC particularly for a design life of 100 years. The long-term losses are mainly due to relaxation of prestressing cables, creep and shrinkage of concrete. The loss of prestress due to relaxation of prestressing cables is considered to be severe due to temperature effects. In this paper an effort has been made to understand the loss of prestress due to relaxation of steel at different temperatures namely 20 degC, 25 degC, 30 degC, 35 degC, 40 degC and 45 degC and the results up to 1000 hrs to estimate the losses over longer life of structures. The initial prestress was maintained at 0.70 times guaranteed ultimate tensile strength (GUTS) of cables. The prestressing loss due to relaxation of prestressing cables increases as the temperature increases. (author)

  16. Relaxation cracking in the process industry, an underestimated problem

    Energy Technology Data Exchange (ETDEWEB)

    Wortel, J.C. van [TNO Institute of Industrial Technology, Apeldoorn (Netherlands)

    1998-12-31

    Austenitic components, operating between 500 and 750 deg C, can fail within 1 year service while the ordinary mechanical properties after failure are still within the code requirements. The intergranular brittle failures are situated in the welded or cold deformed areas. This type of cracking has many names, showing the uncertainty concerning the mechanism for the (catastrophical) failures. A just finished investigation showed that it is a relaxation crack problem, introduced by manufacturing processes, especially welding and cold rolling. Cracking/failures can be expected after only 0.1- 0.2 % relaxation strain. These low strain values can already be generated during relaxation of the welding stresses. Especially coarse grained `age hardening` materials are susceptible. Stabilising and Postweld Heat Treatments are very effective to avoid relaxation crack problems during operation. After these heat treatments the components can withstand more than 2 % relaxation strain. At temperatures between 500 and 750 deg C relaxation cracking is the predominant factor for the safety and lifetime of welded austenitic components. (orig.) 12 refs.

  17. Relaxation cracking in the process industry, an underestimated problem

    Energy Technology Data Exchange (ETDEWEB)

    Wortel, J.C. van [TNO Institute of Industrial Technology, Apeldoorn (Netherlands)

    1999-12-31

    Austenitic components, operating between 500 and 750 deg C, can fail within 1 year service while the ordinary mechanical properties after failure are still within the code requirements. The intergranular brittle failures are situated in the welded or cold deformed areas. This type of cracking has many names, showing the uncertainty concerning the mechanism for the (catastrophical) failures. A just finished investigation showed that it is a relaxation crack problem, introduced by manufacturing processes, especially welding and cold rolling. Cracking/failures can be expected after only 0.1- 0.2 % relaxation strain. These low strain values can already be generated during relaxation of the welding stresses. Especially coarse grained `age hardening` materials are susceptible. Stabilising and Postweld Heat Treatments are very effective to avoid relaxation crack problems during operation. After these heat treatments the components can withstand more than 2 % relaxation strain. At temperatures between 500 and 750 deg C relaxation cracking is the predominant factor for the safety and lifetime of welded austenitic components. (orig.) 12 refs.

  18. Sawtooth oscillations as MHD relaxation process in a plasma

    International Nuclear Information System (INIS)

    Yoshida, Zensho; Inoue, Nobuyuki; Ogawa, Yuichi

    1992-01-01

    The sawtooth oscillation in a tokamak plasma is a spontaneous relaxation process accompanying global instabilities which behave to reduce the internal magnetic energy. This phenomenon has a similarity to the MHD relaxation processes in Reversed Field Pinch (RFP) and Ultra Low Q (ULQ) plasmas. The self-stabilizing effect of instabilities with m (poloidal mode number) = 1 results in an increase in the central safety factor q(0). Nonlinear dynamics of m = 1 instabilities has been discussed both for global and local modes. The latter appears when a pitch minimum exists in the plasma, and is relevant to the compound sawtooth oscillation. The MHD relaxation is a restructuring process of the plasma current profile that is competitive with the resistive diffusion. (author)

  19. The Effect of Phonon Relaxation Process on Absorption Spectra ...

    African Journals Online (AJOL)

    In this work we study the effect of phonon relaxation process on the absorption spectra using the Green's function technique. The Green's function technique which is widely used in many particle problems is used to solve the Kubo formula which describes the optical absorption process. Finally the configurational diagram is ...

  20. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    Energy Technology Data Exchange (ETDEWEB)

    Fries, Pascal H., E-mail: pascal-h.fries@cea.fr [Université Grenoble Alpes, INAC-SCIB, RICC, F-38000 Grenoble (France); CEA, INAC-SCIB, RICC, F-38000 Grenoble (France); Belorizky, Elie [Université Grenoble Alpes, LIPHY, F-38000 Grenoble (France); CEA, Leti-Clinatec, F-38000 Grenoble (France)

    2015-07-28

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R{sub 1} of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R{sub 1} vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S–I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole {sup 14}N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of {sup 27}Al (S = 5/2) nuclei is also explained.

  1. Coherence and relaxation in energy transfer processes in condensed phases

    International Nuclear Information System (INIS)

    Shelby, R.M.

    1978-03-01

    Investigations of electronic triplet and vibrational energy transfer dynamics and relaxation processes are presented. Emphasis is placed on understanding the role of coherence and interactions which tend to destroy the coherence. In the case of triplet excitons at low temperatures, the importance of coherence in energy migration can be established, and the average coherence parameters can be experimentally determined. In the case of vibrational excitations, both picosecond spectroscopic studies of vibrational relaxation and spontaneous Raman spectroscopy are used to characterize the dynamics and give increased insight into the nature of the mechanisms responsible for vibrational dephasing. The design and operation of the picosecond apparatus used in these experiments is also described

  2. An approach to the magnetic relaxation processes in lithium ferrites

    International Nuclear Information System (INIS)

    Torres, C.; Gonzalez Arias, A.; Hernandez-Gomez, P.; Francisco, C. de; Alejos, O.; Munoz, J.M.; Zazo, M.

    2007-01-01

    The relaxation of the initial magnetic permeability has been measured in polycrystalline Li x Fe 3- x O 4 samples, with x ranging from 0 to 0.5, by means of the magnetic disaccommodation (DA) technique. We have found that there is no abrupt transition for a given composition, but there is a progressive modification of the characteristic relaxation processes of magnetite. These results have been interpreted on the basis of the increasing amount of Li ions in the spinel lattice and hence, the resulting modifications on their proximities

  3. 5 CFR 732.301 - Due process.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Due process. 732.301 Section 732.301...) NATIONAL SECURITY POSITIONS Due Process and Reporting § 732.301 Due process. When an agency makes an... any determination. (b) Comply with all applicable administrative due process requirements, as provided...

  4. Microscopic dynamics and relaxation processes in liquid hydrogen fluoride

    International Nuclear Information System (INIS)

    Angelini, R.; Giura, P.; Monaco, G.; Sette, F.; Fioretto, D.; Ruocco, G.

    2004-01-01

    Inelastic x-ray scattering and Brillouin light scattering measurements of the dynamic structure factor of liquid hydrogen fluoride have been performed in the temperature range T=214-283 K. The data, analyzed using a viscoelastic model with a two time-scale memory function, show a positive dispersion of the sound velocity c(Q) between the low frequency value c 0 (Q) and the high frequency value c ∞α (Q). This finding confirms the existence of a structural (α) relaxation directly related to the dynamical organization of the hydrogen bonds network of the system. The activation energy E a of the process has been extracted by the analysis of the temperature behavior of the relaxation time τ α (T) that follows an Arrhenius law. The obtained value for E a , when compared with that observed in another hydrogen bond liquid as water, suggests that the main parameter governing the α-relaxation process is the number of hydrogen bonds per molecule

  5. Relaxation processes and physical aging in metallic glasses

    Science.gov (United States)

    Ruta, B.; Pineda, E.; Evenson, Z.

    2017-12-01

    Since their discovery in the 1960s, metallic glasses have continuously attracted much interest across the physics and materials science communities. In the forefront are their unique properties, which hold the alluring promise of broad application in fields as diverse as medicine, environmental science and engineering. However, a major obstacle to their wide-spread commercial use is their inherent temporal instability arising from underlying relaxation processes that can dramatically alter their physical properties. The result is a physical aging process which can bring about degradation of mechanical properties, namely through embrittlement and catastrophic mechanical failure. Understanding and controlling the effects of aging will play a decisive role in our on-going endeavor to advance the use of metallic glasses as structural materials, as well as in the more general comprehension of out-of-equilibrium dynamics in complex systems. This review presents an overview of the current state of the art in the experimental advances probing physical aging and relaxation processes in metallic glasses. Similarities and differences between other hard and soft matter glasses are highlighted. The topic is discussed in a multiscale approach, first presenting the key features obtained in macroscopic studies, then connecting them to recent novel microscopic investigations. Particular emphasis is put on the occurrence of distinct relaxation processes beyond the main structural process in viscous metallic melts and their fate upon entering the glassy state, trying to disentangle results and formalisms employed by the different groups of the glass-science community. A microscopic viewpoint is presented, in which physical aging manifests itself in irreversible atomic-scale processes such as avalanches and intermittent dynamics, ascribed to the existence of a plethora of metastable glassy states across a complex energy landscape. Future experimental challenges and the comparison with

  6. Proton relaxation relationships of human and animal tissues in vitro. Changes due to autolysis and fixing

    International Nuclear Information System (INIS)

    Grodd, W.; Schmitt, W.G.H.

    1983-01-01

    The results of measurements of proton relaxation times of various tissues from rats, pigs and humans are reported; these were obtained by a resonance spectroscope at 20 MHz and 40 0 C. There were specific differences in both relaxation times (T 1 and T 2 ) of the liver and spleen. There was a difference of more than 150 ms in the longitudinal relaxation time between grey and white cerebral tissue. Autolytic changes show an increase in both relaxation times. Fixation produced a reduction in T 1 only. The significance of these findings for NMR tomography is discussed. (orig.) [de

  7. On γ-relaxation process in crystallizable polymers

    International Nuclear Information System (INIS)

    Mindiyarov, Kh.G.; Zelenev, Yu.V.; Bartenev, G.M.

    1975-01-01

    In the present paper, with the aid of radiothermoluminescence technique γ-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to γ-rays of Co 60 at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the α - γ-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP α-maximum may be absent. Dependence has been studied of the luminescence intensity in the α- and γ-maxima (Isub(α)/Isub(γ)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(γ)re of crystallinity degree

  8. Nuclear spin relaxation due to chemical shift anisotropy of gas-phase 129Xe.

    Science.gov (United States)

    Hanni, Matti; Lantto, Perttu; Vaara, Juha

    2011-08-14

    Nuclear spin relaxation provides detailed dynamical information on molecular systems and materials. Here, first-principles modeling of the chemical shift anisotropy (CSA) relaxation time for the prototypic monoatomic (129)Xe gas is carried out, both complementing and predicting the results of NMR measurements. Our approach is based on molecular dynamics simulations combined with pre-parametrized ab initio binary nuclear shielding tensors, an "NMR force field". By using the Redfield relaxation formalism, the simulated CSA time correlation functions lead to spectral density functions that, for the first time, quantitatively determine the experimental spin-lattice relaxation times T(1). The quality requirements on both the Xe-Xe interaction potential and binary shielding tensor are investigated in the context of CSA T(1). Persistent dimers Xe(2) are found to be responsible for the CSA relaxation mechanism in the low-density limit of the gas, completely in line with the earlier experimental findings.

  9. Anomalous relaxation and self-organization in nonequilibrium processes

    International Nuclear Information System (INIS)

    Fatkullin, Ibrahim; Kladko, Konstantin; Mitkov, Igor; Bishop, A. R.

    2001-01-01

    We study thermal relaxation in ordered arrays of coupled nonlinear elements with external driving. We find that our model exhibits dynamic self-organization manifested in a universal stretched-exponential form of relaxation. We identify two types of self-organization, cooperative and anticooperative, which lead to fast and slow relaxation, respectively. We give a qualitative explanation for the behavior of the stretched exponent in different parameter ranges. We emphasize that this is a system exhibiting stretched-exponential relaxation without explicit disorder or frustration

  10. Constitutional Due Process and Educational Administration.

    Science.gov (United States)

    Uerling, Donald F.

    1985-01-01

    Discusses substantive and procedural due process as required by the United States Constitution and interpreted by the Supreme Court, with particular reference to situations arising in educational environments. Covers interests protected by due process requirements, the procedures required, and some special considerations that may apply. (PGD)

  11. Procedural Due Process Rights in Student Discipline.

    Science.gov (United States)

    Pressman, Robert; Weinstein, Susan

    To assist administrators in understanding procedural due process rights in student discipline, this manual draws together hundreds of citations and case summaries of federal and state court decisions and provides detailed commentary as well. Chapter 1 outlines the general principles of procedural due process rights in student discipline, such as…

  12. Dynamic stress relaxation due to cyclic variation of strain at elevated temperature

    International Nuclear Information System (INIS)

    Suzuki, F.

    1975-01-01

    The relaxation of stress which occurs when low amplitude alternating strains are superimposed on constant mean total strains is studied in this paper. Experiments were carried out on a 0.16 per cent carbon steel and an AISI 347 stainless steel at 450 0 C and 650 0 C respectively in which the decrease of axial mean stress was measured as a function of time. When even a low amplitude alternating strain was applied, the rate of stress relaxation was observed to increase. Analytical predictions based on creep and static relaxation data show fairly good agreement with experiments in the period corresponding to transient creep. (author)

  13. Quenching of exciton luminescence due to impact ionization and mechanisms of electron relaxation in cadmium sulphide

    International Nuclear Information System (INIS)

    Kagan, V.D.; Karpenko, S.L.; Katilyus, R.

    1989-01-01

    Quenching of exciton luminescence in the constant electric field in cadmium sulfide at 1.8K, caused by impact ionization of free and delocalization of bound excitons by hot electrons is observed. When the field is increase up to 1 kW/cm continuous transfer from the Taundsen-Shockley law to the Davydov-Wolf one takes place. Among the samples studied pure samples are distinguished by the exciton spectrum, where, as it is shown in the work, the high-energy electrons lose quasipulse, radiating spontaneously piezophonons; in other samples scattering on impurities prevails. Theoretical processing of data on the bound exciton radiation line quenching in the moderate field region presents about 10 -4 values in pure and about 5x10 -6 cm ones in other samples for the 4 MeV energy electron free flight length. So, the optical methods used allowed one to determine high-energy electron relaxation mechanisms, prevailing in CdS at low temperature

  14. Continuous relaxation time spectrum of α-process in glass-like B2O3

    International Nuclear Information System (INIS)

    Bartenev, G.M.; Lomovskij, V.A.

    1991-01-01

    α-process of relaxation of glass-like B 2 O 3 was investigated in a wide temperature range. Continuous spectrum of relaxation times H(τ) for this process was constructed, using data of dynamic methods of investigation. It is shown that increase of temperature of α-process investigation leads to change of glass-like BaO 3 structure in such a way, that H(τ) spectrum tends to the maxwell one with a unit relaxation time

  15. Characterization of relaxation processes in interacting vortex matter through a time-dependent correlation length

    International Nuclear Information System (INIS)

    Pleimling, Michel; Täuber, Uwe C

    2015-01-01

    Vortex lines in type-II superconductors display complicated relaxation processes due to the intricate competition between their mutual repulsive interactions and pinning to attractive point or extended defects. We perform extensive Monte Carlo simulations for an interacting elastic line model with either point-like or columnar pinning centers. From measurements of the space- and time-dependent height-height correlation function for lateral flux line fluctuations, we extract a characteristic correlation length that we use to investigate different non-equilibrium relaxation regimes. The specific time dependence of this correlation length for different disorder configurations displays characteristic features that provide a novel diagnostic tool to distinguish between point-like pinning centers and extended columnar defects. (paper)

  16. Uncertainty management by relaxation of conflicting constraints in production process scheduling

    Science.gov (United States)

    Dorn, Juergen; Slany, Wolfgang; Stary, Christian

    1992-01-01

    Mathematical-analytical methods as used in Operations Research approaches are often insufficient for scheduling problems. This is due to three reasons: the combinatorial complexity of the search space, conflicting objectives for production optimization, and the uncertainty in the production process. Knowledge-based techniques, especially approximate reasoning and constraint relaxation, are promising ways to overcome these problems. A case study from an industrial CIM environment, namely high-grade steel production, is presented to demonstrate how knowledge-based scheduling with the desired capabilities could work. By using fuzzy set theory, the applied knowledge representation technique covers the uncertainty inherent in the problem domain. Based on this knowledge representation, a classification of jobs according to their importance is defined which is then used for the straightforward generation of a schedule. A control strategy which comprises organizational, spatial, temporal, and chemical constraints is introduced. The strategy supports the dynamic relaxation of conflicting constraints in order to improve tentative schedules.

  17. Non-rigid ultrasound image registration using generalized relaxation labeling process

    Science.gov (United States)

    Lee, Jong-Ha; Seong, Yeong Kyeong; Park, MoonHo; Woo, Kyoung-Gu; Ku, Jeonghun; Park, Hee-Jun

    2013-03-01

    This research proposes a novel non-rigid registration method for ultrasound images. The most predominant anatomical features in medical images are tissue boundaries, which appear as edges. In ultrasound images, however, other features can be identified as well due to the specular reflections that appear as bright lines superimposed on the ideal edge location. In this work, an image's local phase information (via the frequency domain) is used to find the ideal edge location. The generalized relaxation labeling process is then formulated to align the feature points extracted from the ideal edge location. In this work, the original relaxation labeling method was generalized by taking n compatibility coefficient values to improve non-rigid registration performance. This contextual information combined with a relaxation labeling process is used to search for a correspondence. Then the transformation is calculated by the thin plate spline (TPS) model. These two processes are iterated until the optimal correspondence and transformation are found. We have tested our proposed method and the state-of-the-art algorithms with synthetic data and bladder ultrasound images of in vivo human subjects. Experiments show that the proposed method improves registration performance significantly, as compared to other state-of-the-art non-rigid registration algorithms.

  18. Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

    Directory of Open Access Journals (Sweden)

    J. W. Zhang

    2017-10-01

    Full Text Available As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC. In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

  19. Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

    Science.gov (United States)

    Zhang, J. W.; Zhou, T. C.; Wang, J. X.; Yang, X. F.; Zhu, F.; Tian, L. M.; Liu, R. T.

    2017-10-01

    As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC). In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

  20. Some kinetic and spectroscopic evidence on intramolecular relaxation processes in polyatomic molecules

    International Nuclear Information System (INIS)

    Quack, M.

    1983-01-01

    The description and definition of intramolecular vibrational relaxation processes is discussed within the framework of the quantum mechanical and statistical mechanical equations of motion. The evidence from quite different experimental sources is summarized under the common aspect of vibrational relaxation. Although much of the evidence remains ambiguous, there is good indication that a localized vibrational excitation relaxes typically in 0.1 to 10 picoseconds, which is long compared to many optical and reactive processes

  1. Inhomogeneous Relaxation of a Molecular Layer on an Insulator due to Compressive Stress

    Science.gov (United States)

    Bocquet, F.; Nony, L.; Mannsfeld, S. C. B.; Oison, V.; Pawlak, R.; Porte, L.; Loppacher, Ch.

    2012-05-01

    We discuss the inhomogeneous stress relaxation of a monolayer of hexahydroxytriphenylene (HHTP) which adopts the rare line-on-line (LOL) coincidence on KCl(001) and forms moiré patterns. The fact that the hexagonal HHTP layer is uniaxially compressed along the LOL makes this system an ideal candidate to discuss the influence of inhomogeneous stress relaxation. Our work is a combination of noncontact atomic force microscopy experiments, density functional theory and potential energy calculations, and a thorough interpretation by means of the Frenkel-Kontorova model. We show that the assumption of a homogeneous molecular layer is not valid for this organic-inorganic heteroepitaxial system since the best calculated energy configuration correlates with the experimental data only if inhomogeneous relaxations of the layer are taken into account.

  2. Multiple relaxation processes in high-energy ion irradiated kapton-H polyimide: Thermally stimulated depolarization current study

    International Nuclear Information System (INIS)

    Garg, Maneesha; Quamara, J.K.

    2006-01-01

    High-energy ion irradiation effects on the thermally stimulated depolarization current (Tdc) behaviour of kapton-H samples (12.5 μm) irradiated with 50 MeV Li ion (fluence 5 x 10 4 , 10 5 and 5 x 10 5 ions/cm 2 ) have been investigated. The TSDC spectra of the irradiated samples reveal that the β-peak (appearing around 80-110 deg. C) associated with dipolar relaxation has been significantly affected owing to the demerization of carbonyl groups due to irradiation. The TSDC spectra also reveal a new relaxation process (termed as γ-relaxation) around 30 deg. C, due to increased water absorptivity in irradiated samples. The peak around 200 deg. C (α-peak) associated with space charge relaxation process also shows a behavioural change with ion irradiation. The peak not only shifts towards the higher temperature with increasing fluence but also show an increase in its activation energy (0.33-0.99 eV) with increasing polarizing field. The creation of new deep energy trap centers due to the formation of conjugated bonds after irradiation is responsible for this modification. The Cole-Cole distribution curves show the formation of new sub-polar group with different characteristic relaxation time

  3. Relaxation processes and structural transformations in amorphous Co-Fe-Si-B alloys

    International Nuclear Information System (INIS)

    Dus-Sitek, M.; Olszowski, Z.

    1994-01-01

    The thermostimulated electron emission (TSEE) method was applied for determination of relaxation and crystallization processes in amorphous alloys. By using the analogy of DTA-method, the activation energy of relaxation and crystallization processes has been determined from the measurements of changes of TSEE temperature maxima depending on the heating rate

  4. Multiple-decker phthalocyaninato dinuclear lanthanoid(III) single-molecule magnets with dual-magnetic relaxation processes.

    Science.gov (United States)

    Katoh, Keiichi; Horii, Yoji; Yasuda, Nobuhiro; Wernsdorfer, Wolfgang; Toriumi, Koshiro; Breedlove, Brian K; Yamashita, Masahiro

    2012-11-28

    The SMM behaviour of dinuclear Ln(III)-Pc multiple-decker complexes (Ln = Tb(3+) and Dy(3+)) with energy barriers and slow-relaxation behaviour were explained by using X-ray crystallography and static and dynamic susceptibility measurements. In particular, interactions among the 4f electrons of several dinuclear Ln(III)-Pc type SMMs have never been discussed on the basis of the crystal structure. For dinuclear Tb(III)-Pc complexes, a dual magnetic relaxation process was observed. The relaxation processes are due to the anisotropic centres. Our results clearly show that the two Tb(3+) ion sites are equivalent and are consistent with the crystal structure. On the other hand, the mononuclear Tb(III)-Pc complex exhibited only a single magnetic relaxation process. This is clear evidence that the magnetic relaxation mechanism depends heavily on the dipole-dipole (f-f) interactions between the Tb(3+) ions in the dinuclear systems. Furthermore, the SMM behaviour of dinuclear Dy(III)-Pc type SMMs with smaller energy barriers compared with that of Tb(III)-Pc and slow-relaxation behaviour was explained. Dinuclear Dy(III)-Pc SMMs exhibited single-component magnetic relaxation behaviour. The results indicate that the magnetic relaxation properties of dinuclear Ln(III)-Pc multiple-decker complexes are affected by the local molecular symmetry and are extremely sensitive to tiny distortions in the coordination geometry. In other words, the spatial arrangement of the Ln(3+) ions (f-f interactions) in the crystal is important. Our work shows that the SMM properties can be fine-tuned by introducing weak intermolecular magnetic interactions in a controlled SMM spatial arrangement.

  5. Contract Law, Due Process, and the NCAA.

    Science.gov (United States)

    Dickerson, Jaffe D.; Chapman, Mayer

    1978-01-01

    The NCAA has enjoyed almost total freedom from judicial scrutiny of its rules, procedures, and official acts in large part because of its private nature as an unincorporated association. The function of the NCAA, California State University, Hayward v NCAA, and due process of the student-athlete are discussed. (MLW)

  6. AFT Chief Promises Due-Process Reform

    Science.gov (United States)

    Sawchuk, Stephen

    2010-01-01

    The president of the American Federation of Teachers (AFT), Randi Weingarten, is putting the sensitive issue of due process on the education reform table, with a pledge to work with districts to streamline the often-cumbersome procedures for dismissing teachers who fail to improve their performance after receiving help and support. She has also…

  7. Evaluation of biexponential relaxation processes by magnetic resonance imaging. A phantom study

    DEFF Research Database (Denmark)

    Kjaer, L; Thomsen, C; Larsson, H B

    1988-01-01

    Despite the complexity of biologic tissues, a monoexponential behaviour is usually assumed when estimating relaxation processes in vivo by magnetic resonance imaging (MRI). This study was designed to evaluate the potential of biexponential decomposition of T1 and T2 relaxation curves obtained at 1...... echoes. Applying biexponential curve analysis, a significant deviation from a monoexponential behaviour was recognized at a ratio of corresponding relaxation rates of about 3 and 2, estimating T1 and T2 relaxation, respectively (p less than 0.01, F-test). Requiring an SD less than or equal to 10 per cent...

  8. Energy and Momentum Relaxation Times of 2D Electrons Due to Near Surface Deformation Potential Scattering

    Science.gov (United States)

    Pipa, Viktor; Vasko, Fedor; Mitin, Vladimir

    1997-03-01

    The low temperature energy and momentum relaxation rates of 2D electron gas placed near the free or clamped surface of a semi-infinit sample are calculated. To describe the electron-acoustic phonon interaction with allowance of the surface effect the method of elasticity theory Green functions was used. This method allows to take into account the reflection of acoustic waves from the surface and related mutual conversion of LA and TA waves. It is shown that the strength of the deformation potential scattering at low temperatures substantially depends on the mechanical conditions at the surface: relaxation rates are suppressed for the free surface while for the rigid one the rates are enhanced. The dependence of the conductivity on the distance between the 2D layer and the surface is discussed. The effect is most pronounced in the range of temperatures 2 sl pF < T < (2 hbar s_l)/d, where pF is the Fermi momentum, sl is the velocity of LA waves, d is the width of the quantum well.

  9. Relaxation process of coherent transients in the presence of an adjacent strongly driven transition

    International Nuclear Information System (INIS)

    Feng Xiaomin; Yang Lijun; Li Xiaoli; Zhang Lianshui; Han Li; Guo Qinglin; Fu Guangsheng

    2007-01-01

    Coherent transient occurs when a two-level transition is subjected to pulsed laser excitation. The relaxation process of coherent transient depends on both the longitudinal and transverse relaxation parameters of the two-level transition, which is related to the population and coherence decay rates. In this paper we study relaxation process of a new type coherent transients observed by applying a pulsed laser excitation to a two-level transition in the presence of a second strong continuous-wave (cw) coherent field coupling one of the two levels to a third level, that is, in a three-level double-resonance configuration. The relaxation process of coherent transients is studied as a function of relaxation parameters of both the two-level transition excited by the pulsed laser field and the transition coupled by the cw laser field. It is shown that by involving a third level with coherent field the relaxation process of coherent transients of a two-level transition can be modified. Our study illustrates a new way of controlling relaxation process of coherent transients in a two-level transition by a second coherent laser and this has important implication for quantum information storage and quantum computing

  10. Nuclear spin relaxation due to hydrogen diffusion in b.c.c. metals

    International Nuclear Information System (INIS)

    Faux, D.A.; Hall, C.K.

    1989-01-01

    We present Monte Carlo simulation results for the proton-proton contribution to the T 1 -1 relaxation rate for hydrogen spins diffusing on the tetrahedral sites of a b.c.c. metal. It is assumed that each hydrogen blocks all sites to the zeroth (no multiple-occupancy), second or third neighbour and that longer-range interactions may be neglected. Comparisons are made to the BPP and Torrey models. It is found that both the BPP and Torrey models give reasonable values for the peak height but that their predictions for the peak position and the high- and low-temperature limit are in error, particularly for large blocking distances. (orig.)

  11. Hopping ladder and power relaxation due to donor-acceptor pairs

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1985-11-01

    Hopping between donor-acceptor pairs leads to peculiar temperature dependence of the conductivity and the photoconductivity under subband gap illumination in the form of non-linear activation energies ladder. The correlated and uncorrelated distributions of pairs are considered and the conditions for the ladder existence are determined. The relaxation of the carrier concentration fluctuations is studied and power type decay is found. The temperature dependence of the exponent is calculated in agreement with the non-exponential decay of the pulse excited luminescence observed by Dean et al. The temperature dependence of the luminescence intensity also shows variable activation energy as found here. The exponent value α=1.316 is also in agreement with the data for crystalline and amorphous materials. (author)

  12. Estimation of magnetic relaxation property for CVD processed YBCO-coated conductors

    International Nuclear Information System (INIS)

    Takahashi, Y.; Kiuchi, M.; Otabe, E.S.; Matsushita, T.; Shikimachi, K.; Watanabe, T.; Kashima, N.; Nagaya, S.

    2010-01-01

    Ion Beam Assist Deposition/Chemical Vapor Deposition(IBAD/CVD)-processed YBCO-coated conductors with high critical current density J c at high magnetic fields are expected to be applied to superconducting equipments such as superconducting magnetic energy storage (SMES). For application to superconducting magnet in SMES one of the most important properties for superconductors is the relaxation property of superconducting current. In this paper, the relaxation property is investigated for IBAD/CVD-processed YBCO-coated conductors of the superconducting layer in the range of 0.18-0.90 μm. This property can be quantitatively characterized by the apparent pinning potential, U 0 *. It is found that U 0 * takes a smaller value due to the two-dimensional pinning mechanism at high magnetic fields for conductor with thinner superconducting layer. Although U 0 * decreases with increasing thickness at low magnetic fields at 20 K, it increases at high magnetic fields. The results are theoretically explained by the model of the flux creep and flow based on the dimensionality of flux pinning. Scaling analysis is examined for the dependence of U 0 * on the magnetic field, temperature and the layer thickness.

  13. Anisotropy and relaxation processes of uniaxially oriented CoFe2O4 nanoparticles dispersed in PDMS

    International Nuclear Information System (INIS)

    Antonel, P.S.; Negri, R.M.; Leyva, A.G.; Jorge, G.A.

    2012-01-01

    When a uniaxial magnetic field is applied to a non-magnetic dispersive medium filled with magnetic nanoparticles, they auto-assemble into thin needles parallel to the field direction, due to the strong dipolar interaction among them. We have prepared in this way magnetically oriented nanocomposites of nanometer-size CoFe 2 O 4 particles in a polydimethylsiloxane polymer matrix, with 10% w/w of magnetic particles. We present the characteristic magnetic relaxation curves measured after the application of a magnetic field forming an angle α with respect to the needle direction. We show that the magnetic viscosity (calculated from the logarithmic relaxation curves) as a function of α presents a minimum at α=0, indicating slower relaxation processes associated with this configuration of fields. The results seems to point out that the local magnetic anisotropy of the nanoparticles is oriented along the needles, resulting in the macroscopic magnetic anisotropy observed in our measurements.

  14. Anisotropy and relaxation processes of uniaxially oriented CoFe{sub 2}O{sub 4} nanoparticles dispersed in PDMS

    Energy Technology Data Exchange (ETDEWEB)

    Antonel, P.S.; Negri, R.M. [Instituto de Quimica Fisica de Materiales, Ambiente y Energia (INQUIMAE), Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon II, Av. Cantilo s/n (1428), Buenos Aires (Argentina); Leyva, A.G. [Grupo de Materia Condensada, Gerencia de Investigacion y Aplicaciones, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499 (1650) San Martin, Pcia. de Buenos Aires, Argentina - Escuela de Ciencia y Tecnologia, UNSAM (Argentina); Jorge, G.A., E-mail: gjorge@df.uba.ar [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, Av. Cantilo s/n (1428), Buenos Aires (Argentina)

    2012-08-15

    When a uniaxial magnetic field is applied to a non-magnetic dispersive medium filled with magnetic nanoparticles, they auto-assemble into thin needles parallel to the field direction, due to the strong dipolar interaction among them. We have prepared in this way magnetically oriented nanocomposites of nanometer-size CoFe{sub 2}O{sub 4} particles in a polydimethylsiloxane polymer matrix, with 10% w/w of magnetic particles. We present the characteristic magnetic relaxation curves measured after the application of a magnetic field forming an angle {alpha} with respect to the needle direction. We show that the magnetic viscosity (calculated from the logarithmic relaxation curves) as a function of {alpha} presents a minimum at {alpha}=0, indicating slower relaxation processes associated with this configuration of fields. The results seems to point out that the local magnetic anisotropy of the nanoparticles is oriented along the needles, resulting in the macroscopic magnetic anisotropy observed in our measurements.

  15. Dual resonance approach to optical signal processing beyond the carrier relaxation rate

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Mørk, Jesper

    2014-01-01

    We propose using two optical cavities in a differential control scheme to increase the bandwidth of cavity-based semiconductor optical signal processing devices beyond the limit given by the slowest carrier relaxation rate of the medium.......We propose using two optical cavities in a differential control scheme to increase the bandwidth of cavity-based semiconductor optical signal processing devices beyond the limit given by the slowest carrier relaxation rate of the medium....

  16. Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation

    International Nuclear Information System (INIS)

    Brown, Keith A.; Vassiliou, Christophoros C.; Issadore, David; Berezovsky, Jesse; Cima, Michael J.; Westervelt, R.M.

    2010-01-01

    The aggregation of superparamagnetic iron oxide (SPIO) nanoparticles decreases the transverse nuclear magnetic resonance (NMR) relaxation time T 2 CP of adjacent water molecules measured by a Carr-Purcell-Meiboom-Gill (CPMG) pulse-echo sequence. This effect is commonly used to measure the concentrations of a variety of small molecules. We perform extensive Monte Carlo simulations of water diffusing around SPIO nanoparticle aggregates to determine the relationship between T 2 CP and details of the aggregate. We find that in the motional averaging regime T 2 CP scales as a power law with the number N of nanoparticles in an aggregate. The specific scaling is dependent on the fractal dimension d of the aggregates. We find T 2 CP ∝Ν -0.44 for aggregates with d=2.2, a value typical of diffusion limited aggregation. We also find that in two-nanoparticle systems, T 2 CP is strongly dependent on the orientation of the two nanoparticles relative to the external magnetic field, which implies that it may be possible to sense the orientation of a two-nanoparticle aggregate. To optimize the sensitivity of SPIO nanoparticle sensors, we propose that it is best to have aggregates with few nanoparticles, close together, measured with long pulse-echo times.

  17. CdZnTe quantum dots study: energy and phase relaxation process

    International Nuclear Information System (INIS)

    Viale, Yannick

    2004-01-01

    We present a study of the electron-hole pair energy and phase relaxation processes in a CdTe/ZnTe heterostructure, in which quantum dots are embedded. CdZnTe quantum wells with a high Zinc concentration, separated by ZnTe barriers, contain islands with a high cadmium concentration. In photoluminescence excitation spectroscopy experiments, we evidence two types of electron hole pair relaxation processes. After being excited in the CdZnTe quantum well, the pairs relax their energy by emitting a cascade of longitudinal optical phonons until they are trapped in the quantum dots. Before their radiative recombination follows an intra-dot relaxation, which is attributed to a lattice polarization mechanism of the quantum dots. It is related to the coupling between the electronic and the vibrational states. Both relaxation mechanisms are reinforced by the strong polar character of the chemical bond in II-VI compounds. Time resolved measurements of transmission variations in a pump-probe configuration allowed us to investigate the population dynamics of the electron-hole pairs during the relaxation process. We observe a relaxation time of about 2 ps for the longitudinal phonon emission cascade in the quantum well before a saturation of the quantum dot transition. We also measured an intra-box relaxation time of 25 ps. The comparison of various cascades allows us to estimate the emission time of a longitudinal optical phonon in the quantum well to be about 100 fs. In four waves mixing experiments, we observe oscillations that we attribute to quantum beats between excitonic and bi-excitonic transitions. The dephasing times that we measure as function of the density of photons shows that excitons are strongly localized in the quantum dots. The excitonic dephasing time is much shorter than the radiative lifetime and is thus controlled by the intra-dot relaxation time. (author) [fr

  18. Relaxation processes in a lower disorder order transition diblock copolymer

    International Nuclear Information System (INIS)

    Sanz, Alejandro; Ezquerra, Tiberio A.; Nogales, Aurora; Hernández, Rebeca; Sprung, Michael

    2015-01-01

    The dynamics of lower disorder-order temperature diblock copolymer leading to phase separation has been observed by X ray photon correlation spectroscopy. Two different modes have been characterized. A non-diffusive mode appears at temperatures below the disorder to order transition, which can be associated to compositional fluctuations, that becomes slower as the interaction parameter increases, in a similar way to the one observed for diblock copolymers exhibiting phase separation upon cooling. At temperatures above the disorder to order transition T ODT , the dynamics becomes diffusive, indicating that after phase separation in Lower Disorder-Order Transition (LDOT) diblock copolymers, the diffusion of chain segments across the interface is the governing dynamics. As the segregation is stronger, the diffusive process becomes slower. Both observed modes have been predicted by the theory describing upper order-disorder transition systems, assuming incompressibility. However, the present results indicate that the existence of these two modes is more universal as they are present also in compressible diblock copolymers exhibiting a lower disorder-order transition. No such a theory describing the dynamics in LDOT block copolymers is available, and these experimental results may offer some hints to understanding the dynamics in these systems. The dynamics has also been studied in the ordered state, and for the present system, the non-diffusive mode disappears and only a diffusive mode is observed. This mode is related to the transport of segment in the interphase, due to the weak segregation on this system

  19. Intra-well relaxation process in magnetic fluids subjected to strong polarising fields

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.N., E-mail: cmarin@physics.uvt.ro [West University of Timisoara, Faculty of Physics, B-dul V. Parvan, No. 4, Timisoara 300223 (Romania); Fannin, P.C. [Department of Electronic and Electrical Engineering, Trinity College, Dublin 2 (Ireland); Malaescu, I.; Barvinschi, P.; Ercuta, A. [West University of Timisoara, Faculty of Physics, B-dul V. Parvan, No. 4, Timisoara 300223 (Romania)

    2012-02-15

    We report on the frequency and field dependent complex magnetic susceptibility measurements of a kerosene-based magnetic fluid with iron oxide nanoparticles, stabilized with oleic acid, in the frequency range 0.1-6 GHz and over the polarising field range of 0-168.4 kA/m. By increasing polarising field, H, a subsidiary loss-peak clearly occurs in the vicinity of the ferromagnetic resonance peak, from which it remains distinct even in strong polarising fields of 168.4 kA/m. This is in contrast to other reported cases in which the intra-well relaxation process is manifested only as a shoulder of the resonance peak, which vanishes in polarising fields larger than that of 100 kA/m. The results of the XRD analysis connected to the anisotropy field results confirm that the investigated sample contains particles of magnetite and of the tetragonal phase of maghemite. Taking into account the characteristics of our sample, the theoretical analysis revealed that the intra-well relaxation process of the small particles of the tetragonal phase of maghemite may be responsible for the subsidiary loss peak of the investigated magnetic fluid. - Highlights: > Intra-well relaxation process in a magnetic fluid is studied. > Sample consists of the tetragonal phase of maghemite and magnetite particles. > A subsidiary relaxation peak is observed in the vicinity of the resonance peak. > Relaxation peak is correlated to the intra-well relaxation process. > It is assigned to the tetragonal phase of maghemite particles.

  20. Direct simulation Monte Carlo modeling of relaxation processes in polyatomic gases

    Science.gov (United States)

    Pfeiffer, M.; Nizenkov, P.; Mirza, A.; Fasoulas, S.

    2016-02-01

    Relaxation processes of polyatomic molecules are modeled and implemented in an in-house Direct Simulation Monte Carlo code in order to enable the simulation of atmospheric entry maneuvers at Mars and Saturn's Titan. The description of rotational and vibrational relaxation processes is derived from basic quantum-mechanics using a rigid rotator and a simple harmonic oscillator, respectively. Strategies regarding the vibrational relaxation process are investigated, where good agreement for the relaxation time according to the Landau-Teller expression is found for both methods, the established prohibiting double relaxation method and the new proposed multi-mode relaxation. Differences and applications areas of these two methods are discussed. Consequently, two numerical methods used for sampling of energy values from multi-dimensional distribution functions are compared. The proposed random-walk Metropolis algorithm enables the efficient treatment of multiple vibrational modes within a time step with reasonable computational effort. The implemented model is verified and validated by means of simple reservoir simulations and the comparison to experimental measurements of a hypersonic, carbon-dioxide flow around a flat-faced cylinder.

  1. Direct simulation Monte Carlo modeling of relaxation processes in polyatomic gases

    International Nuclear Information System (INIS)

    Pfeiffer, M.; Nizenkov, P.; Mirza, A.; Fasoulas, S.

    2016-01-01

    Relaxation processes of polyatomic molecules are modeled and implemented in an in-house Direct Simulation Monte Carlo code in order to enable the simulation of atmospheric entry maneuvers at Mars and Saturn’s Titan. The description of rotational and vibrational relaxation processes is derived from basic quantum-mechanics using a rigid rotator and a simple harmonic oscillator, respectively. Strategies regarding the vibrational relaxation process are investigated, where good agreement for the relaxation time according to the Landau-Teller expression is found for both methods, the established prohibiting double relaxation method and the new proposed multi-mode relaxation. Differences and applications areas of these two methods are discussed. Consequently, two numerical methods used for sampling of energy values from multi-dimensional distribution functions are compared. The proposed random-walk Metropolis algorithm enables the efficient treatment of multiple vibrational modes within a time step with reasonable computational effort. The implemented model is verified and validated by means of simple reservoir simulations and the comparison to experimental measurements of a hypersonic, carbon-dioxide flow around a flat-faced cylinder

  2. Direct simulation Monte Carlo modeling of relaxation processes in polyatomic gases

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, M., E-mail: mpfeiffer@irs.uni-stuttgart.de; Nizenkov, P., E-mail: nizenkov@irs.uni-stuttgart.de; Mirza, A., E-mail: mirza@irs.uni-stuttgart.de; Fasoulas, S., E-mail: fasoulas@irs.uni-stuttgart.de [Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29, D-70569 Stuttgart (Germany)

    2016-02-15

    Relaxation processes of polyatomic molecules are modeled and implemented in an in-house Direct Simulation Monte Carlo code in order to enable the simulation of atmospheric entry maneuvers at Mars and Saturn’s Titan. The description of rotational and vibrational relaxation processes is derived from basic quantum-mechanics using a rigid rotator and a simple harmonic oscillator, respectively. Strategies regarding the vibrational relaxation process are investigated, where good agreement for the relaxation time according to the Landau-Teller expression is found for both methods, the established prohibiting double relaxation method and the new proposed multi-mode relaxation. Differences and applications areas of these two methods are discussed. Consequently, two numerical methods used for sampling of energy values from multi-dimensional distribution functions are compared. The proposed random-walk Metropolis algorithm enables the efficient treatment of multiple vibrational modes within a time step with reasonable computational effort. The implemented model is verified and validated by means of simple reservoir simulations and the comparison to experimental measurements of a hypersonic, carbon-dioxide flow around a flat-faced cylinder.

  3. Residual stress relaxation due to fretting fatigue in shot peened surfaces of Ti-6Al-4V

    International Nuclear Information System (INIS)

    Martinez, S.A.; Blodgett, M.P.; Mall, S.; Sathish, S.; Namjoshi, S.

    2003-01-01

    Fretting fatigue occurs at locations where the materials are sliding against each other under load. In order to enhance the fatigue life under fretting conditions the surface of the component is shot peened. In general, the shot peening process produces a compressive stress on the surface of the material, thereby increasing the resistance of the material to crack initiation. This paper presents the relaxation of residual stress caused during fretting fatigue. X-ray diffraction has been utilized as the method to measure residual stress in fretting fatigued samples of Ti-6Al-4V

  4. Analysis of the kinetics of the fragile fracture process in Mo monocrystals in quasi-relaxation

    International Nuclear Information System (INIS)

    Tamayo Meza, Pedro; Bautista Godinez, Eric Gustavo; Yermishkin, Viacheslav

    2008-01-01

    The method of quasi-relaxation, generally known as the force relaxation method, has been widely applied in the study of elementary dislocational processes. It is essential for the study and analysis of thermoactivated mechanisms, for the determination of the energy of interaction between dislocations and inclusions, in the definition of the dislocational constants, to predict the development of creep, and even for the study of fracture kinetics. For the first time the use of the quasi-relaxation method for evaluating the fragile fracture tendency was presented in the work. However, as usually carried out, the use of mass specimens and the development of a considerable plastic deformation in the vertex of the crack-notch sample limits the possibilities for this method. Many studies analyze the theoretical aspects of the fracture process, and the obtention of reliable quantitative information about the behavior of the dislocation based on an analytical description of the process, and how and when it influences the conditions under which the final catastrophic fracture occurs. This work proposes a new method to analyze the effect of a tension concentrator on the surface of Mo monocrystal specimens. The relaxation of the force and the increase in the crack opening is related to the development of the plastic zone in its vertex with the help of the Irwin correction. During the relaxation, the crack-groove grows until it attains the length of the plastic zone. Specimens with and without force concentrators were tested in quasi-relaxation. The cracks appearing under these conditions are analyzed using a scanning electron microscopy (SEM). The crack appearing in the specimens under load conditions, whose development produced heavy force relaxation, allowed the force relaxation value to be defined and compared in the specimens with and without tension concentrators (au)

  5. Viscoelastic characterization of compacted pharmaceutical excipient materials by analysis of frequency-dependent mechanical relaxation processes

    Science.gov (United States)

    Welch, K.; Mousavi, S.; Lundberg, B.; Strømme, M.

    2005-09-01

    A newly developed method for determining the frequency-dependent complex Young's modulus was employed to analyze the mechanical response of compacted microcrystalline cellulose, sorbitol, ethyl cellulose and starch for frequencies up to 20 kHz. A Debye-like relaxation was observed in all the studied pharmaceutical excipient materials and a comparison with corresponding dielectric spectroscopy data was made. The location in frequency of the relaxation peak was shown to correlate to the measured tensile strength of the tablets, and the relaxation was interpreted as the vibrational response of the interparticle hydrogen and van der Waals bindings in the tablets. Further, the measured relaxation strength, holding information about the energy loss involved in the relaxation processes, showed that the weakest material in terms of tensile strength, starch, is the material among the four tested ones that is able to absorb the most energy within its structure when exposed to external perturbations inducing vibrations in the studied frequency range. The results indicate that mechanical relaxation analysis performed over relatively broad frequency ranges should be useful for predicting material properties of importance for the functionality of a material in applications such as, e.g., drug delivery, drug storage and handling, and also for clarifying the origin of hitherto unexplained molecular processes.

  6. Evaluation of creep damage due to stress relaxation in SA533 grade B class 1 and SA508 class 3 pressure vessel steels

    International Nuclear Information System (INIS)

    Hoffmann, C.L.; Urko, W.

    1993-01-01

    Creep damage can result from stress relaxation of residual stresses in components when exposed to high temperature thermal cycles. Pressure vessels, such as the reactor vessel of the modular high-temperature gas reactor (MHTGR), which normally operate at temperatures well below the creep range can develop relatively high residual stresses in high stress locations. During short term excursions to elevated-temperatures, creep damage can be produced by the loadings on the vessel. In addition, residual stresses will relax out, causing greater creep damage in the pressure vessel material than might otherwise be calculated. The evaluation described in this paper assesses the magnitude of the creep damage due to relaxation of residual stresses resulting from short term exposure of the pressure vessel material to temperatures in the creep range. Creep relaxation curves were generated for SA533 Grade B, Class 1 and SA508 Class 3 pressure vessel steels using finite element analysis of a simple uniaxial truss loaded under constant strain conditions to produce an initial axial stress equal to 1.25 times the material yield strength at temperature. The strain is held constant for 1000 hours at prescribed temperatures from 700 F to 1000 F. The material creep law is used to calculate the relaxed stress for each time increment. The calculated stress relaxation versus time curves are compared with stress relaxation test data. Creep damage fractions are calculated by integrating the stress relaxation versus time curves and performing a linear creep damage summation using the minimum stress to rupture curves at the respective relaxation temperatures. Cumulative creep damage due to stress relaxation as a function of time and temperature is derived from the linear damage summation

  7. Real-time observation of cascaded electronic relaxation processes in p-Fluorotoluene

    Science.gov (United States)

    Hao, Qiaoli; Deng, Xulan; Long, Jinyou; Wang, Yanmei; Abulimiti, Bumaliya; Zhang, Bing

    2017-08-01

    Ultrafast electronic relaxation processes following two photoexcitation of 400 nm in p-Fluorotoluene (pFT) have been investigated utilizing time-resolved photoelectron imaging coupled with time-resolved mass spectroscopy. Cascaded electronic relaxation processes started from the electronically excited S2 state are directly imaged in real time and well characterized by two distinct time constants of 85 ± 10 fs and 2.4 ± 0.3 ps. The rapid component corresponds to the lifetime of the initially excited S2 state, including the structure relaxation from the Franck-Condon region to the conical intersection of S2/S1 and the subsequent internal conversion to the highly excited S1 state. While, the slower relaxation constant is attributed to the further internal conversion to the high levels of S0 from the secondarily populated S1 locating in the channel three region. Moreover, dynamical differences with benzene and toluene of analogous structures, including, specifically, the slightly slower relaxation rate of S2 and the evidently faster decay of S1, are also presented and tentatively interpreted as the substituent effects. In addition, photoelectron kinetic energy and angular distributions reveal the feature of accidental resonances with low-lying Rydberg states (the 3p, 4s and 4p states) during the multi-photon ionization process, providing totally unexpected but very interesting information for pFT.

  8. Atomistic simulation of processes in Ni-base alloys with account for local relaxations

    International Nuclear Information System (INIS)

    Bursik, Jiri

    2007-01-01

    Ordering in Ni-base superalloys is the crucial process controlling the development of the characteristic two-phase microstructure and subsequently the mechanical properties. Systems containing up to six alloying elements typical of advanced Ni-based superalloys are modelled in this work using a Monte Carlo approach with phenomenological Lennard-Jones pair potentials and interactions up to the third coordination sphere. Three-dimensional crystal block is used with over 10 5 atoms. Molecular dynamics approach is used to relax local atomic positions in course of ordering processes under applied stress. The importance of taking into account both relaxation of modelled block dimensions and relaxation of local atomic positions is discussed

  9. Effects of distribution function nonequilibrium tails on relaxation and transfer processes in rarefied gases

    International Nuclear Information System (INIS)

    Grigoryev, Yu.N.; Mikhalitsyn, A.N.; Yanenko, N.N.

    1984-01-01

    Quantitative characteristics of the nonmonotone relaxation process are studied in a gas of pseudo-Maxwell molecules. Basic results are obtained by a direct numerical integration of the nonlinear Boltzmann equation. The evolution of initial distributions being finite or having exponential asymptotics of tails was researched. In particular, initial data obtained by selective excitation (absorption) against the Maxwell background encountered in laser physics problems have been considered. It is shown that under conditions of a developed effect of nonmonotone relaxation the overpopulation in the velocity range 4 <= upsilon <= 10 exceeds on the average 2-3 times the equilibrium value. For the given particles energy the excitation is preserved during t = 5/6 and the total relaxation time of the overpopulation wave reaches t asymptotically equals 20. The amplitudes and the relaxation time of overpopulation in the ''cupola'' region of distribution are substantially lower than in the case of a developed effect in the tail. The influence of the effect on the kinetics of threshold chemical reaction is studied. From the results it follows that in the process of nonmonotone relaxation the mean rates of binary threshold reactions can exceed more than twice the equilibrium values. This estimate is valid for all power like intermolecular repulsive potentials from the pseudo-Maxwell model up to rigid spheres. Time intervals over which the mean reaction rate exceeds considerably the equilibrium one make from 5 to 15 mean free path times increasing with the decrease in the potential ''rigidity''. (author)

  10. Decay of Metastable State with Account of Agglomeration and Relaxation Processes

    Directory of Open Access Journals (Sweden)

    Victor Kurasov

    2016-01-01

    Full Text Available Theoretical description of the metastable phase decay kinetics in the presence of specific connections between the embryos of small sizes has been given. The theory of the decay kinetics in the presence of relaxation processes is constructed in analytical manner. The m-mers nucleation is investigated and the global kinetics of decay is also constructed in this case analytically.

  11. Non-equilibrium reacting gas flows kinetic theory of transport and relaxation processes

    CERN Document Server

    Nagnibeda, Ekaterina; Nagnibeda, Ekaterina

    2009-01-01

    This volume develops the kinetic theory of transport phenomena and relaxation processes in the flows of reacting gas mixtures. The theory is applied to the modeling of non-equilibrium flows behind strong shock waves, in the boundary layer, and in nozzles.

  12. Relaxation of the electron spin in quantum dots via one- and two-phonon processes

    International Nuclear Information System (INIS)

    Calero, C.; Chudnovsky, E.M.; Garanin, D.A.

    2007-01-01

    We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid

  13. Relaxation of the electron spin in quantum dots via one- and two-phonon processes

    Energy Technology Data Exchange (ETDEWEB)

    Calero, C. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)]. E-mail: carlos.calero-borrallo@lehman.cuny.edu; Chudnovsky, E.M. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States); Garanin, D.A. [Department of Physics and Astronomy, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY 10468-1589 (United States)

    2007-09-15

    We have studied direct and Raman processes of the decay of electron spin states in a quantum dot via radiation of phonons corresponding to elastic twists. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid.

  14. Nuclear spin relaxation due to motion on inequivalent sites: H diffusion on O and T sites in the face-centred cubic structure

    International Nuclear Information System (INIS)

    Luo Xinjun; Sholl, C A

    2003-01-01

    Magnetization recoveries for nuclear spin relaxation of like spins due to magnetic dipolar coupling and diffusion on inequivalent sites involve a sum of exponentials. The theory is applied to diffusion on octahedral and tetrahedral interstitial sites in the face-centred cubic structure. Monte Carlo simulations have been used to generate relaxation data for parameters typical for H in metals. It is found that only a single exponential would be observable in the high- and low-temperature limits, but that two-exponential recoveries could be observable in the vicinity of the maximum in the relaxation rate as a function of temperature. The Monte Carlo relaxation data has been fitted using a Bloembergen-Pound-Purcell (BPP) model to assess the accuracy of the BPP model

  15. The modified relaxation time function: A novel analysis technique for relaxation processes. Application to high-temperature molybdenum internal friction peaks

    International Nuclear Information System (INIS)

    Matteo, C.L.; Lambri, O.A.; Zelada-Lambri, G.I.; Sorichetti, P.A.; Garcia, J.A.

    2008-01-01

    The modified relaxation time (MRT) function, which is based on a general linear viscoelastic formalism, has several important mathematical properties that greatly simplify the analysis of relaxation processes. In this work, the MRT is applied to the study of the relaxation damping peaks in deformed molybdenum at high temperatures. The dependence of experimental data from these relaxation processes with temperature are adequately described by a Havriliak-Negami (HN) function, and the MRT makes it possible to find a relation between the parameters of the HN function and the activation energy of the process. The analysis reveals that for the relaxation peak appearing at temperatures below 900 K, the physical mechanism is related to a vacancy-diffusion-controlled movement of dislocations. In contrast, when the peak appears at temperatures higher than 900 K, the damping is controlled by a mechanism of diffusion in the low-temperature tail of the peak, and in the high-temperature tail of the peak the creation plus diffusion of vacancies at the dislocation line occurs

  16. Experimental evidence for simultaneous relaxation processes in super spin glass γ-Fe2O3 nanoparticle system

    Science.gov (United States)

    Nikolic, V.; Perovic, M.; Kusigerski, V.; Boskovic, M.; Mrakovic, A.; Blanusa, J.; Spasojevic, V.

    2015-03-01

    Spherical γ-Fe2O3 nanoparticles with the narrow size distribution of (5 ± 1) nm were synthesized by the method of thermal decomposition from iron acetyl acetonate precursor. The existence of super spin-glass state at low temperatures and in low applied magnetic fields was confirmed by DC magnetization measurements on a SQUID magnetometer. The comprehensive investigation of magnetic relaxation dynamics in low-temperature region was conducted through the measurements of single-stop and multiple stop ZFC memory effects, ZFC magnetization relaxation, and AC susceptibility measurements. The experimental findings revealed the peculiar change of magnetic relaxation dynamics at T ≈ 10 K, which arose as a consequence of simultaneous existence of different relaxation processes in Fe2O3 nanoparticle system. Complementarity of the applied measurements was utilized in order to single out distinct relaxation processes as well as to elucidate complex relaxation mechanisms in the investigated interacting nanoparticle system.

  17. Relaxation processes in optically excites metal clusters; Relaxationsprozesse in optisch angeregten Metallclustern

    Energy Technology Data Exchange (ETDEWEB)

    Stanzel, J.

    2007-08-10

    The present work is concerned with the dynamics of optically excited metal clusters in the gas phase. Small mass-selected gold and tungsten cluster anions (Au{sup -}{sub n}, n=5-8, 14, 20 and W{sup -}{sub n}, n=3-14) are studied using femtosecond time-resolved photoelectron spectroscopy. Depending on the electronic structure in the valence region as well as on the optical excitation energy fundamentally different relaxation processes are observed. In small gold cluster anions excited with 1.56 eV an isolated electronically excited state is populated. The time-dependent measurements are strongly sizedependent and open insights into photoinduced geometry changes of the nuclear framework. Oscillatory vibrational wavepacket motion in Au{sup -}{sub 5}, an extremely longlived ({tau} >90 ns) electronically excited state in Au{sup -}{sub 6} as well as photoinduced melting in Au{sup -}{sub 7} and Au{sup -}{sub 8} is monitored in real time. By increasing the OPTICAL excitation energy to 3.12 eV a completely different scenario is observed. A multitude of electronically excited states can be reached upon optical excitation and as a consequence electronic relaxation processes that take place on a time scale of 1 ps are dominating. This is shown for Au{sup -}{sub 7}, Au{sup -}{sub 14} and Au{sup -}{sub 20}. Compared to gold clusters, tungsten clusters are characterized by a significantly higher electronic density of states in the valence region. Therefore electronic relaxation processes are much more likely and take place on a significantly faster time scale. The fast electronic relaxation processes are distinguished from pure vibrational relaxation. It is shown that already in the four atomic tungsten cluster W{sup -}{sub 4} electronic relaxation processes take place on a time scale of 30 fs. In all investigated tungsten cluster anions (W{sup -}{sub n}, n=3-14) an equilibrium between electronic and vibrational system is reached within around 1 ps after optical excitation which

  18. Influence of relaxation processes on the structure of a thermal boundary layer in partially ionized argon

    International Nuclear Information System (INIS)

    Dongen, M.E.H. van; Eck, R.B. van P. van; Hagebeuk, H.J.L.; Hirschberg, A.; Hutten-Mansfeld, A.C.B.; Jager, H.J.; Willems, J.F.H.

    1981-01-01

    A model for the unsteady thermal boundary-layer development at the end wall of a shock tube, in partially ionized atmospheric argon, is proposed. Consideration is given to ionization and thermal relaxation processes. In order to obtain some insight into the influence of the relaxation processes on the structure of the boundary layer, a study of the frozen and equilibrium limits has been carried out. The transition from a near-equilibrium situation in the outer part of the boundary layer towards a frozen situation near the wall is determined numerically. Experimental data on the electron and atom density profiles obtained from laser schlieren and absorption measurements are presented. A quantitative agreement between theory and experiment is found for a moderate degree of ionization (3%). At a higher degree of ionization the structure of the boundary layer is dominated by the influence of radiation cooling, which has been neglected in the model. (author)

  19. Glass transition and relaxation processes of polymers studied by positron annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science

    1996-10-01

    The glass transition and relaxation processes of polymers were studied by the positron annihilation technique. A positron implanted into polymers might annihilate from positronium (Ps) states in open spaces. Ps is a bound state between a positron and an electron, and its nonrelativistic quantum mechanics is practically identical to that of a hydrogen atom. The lifetime of Ps can be associated with the size of the open spaces, and the formation probability of Ps provides information of motions of molecules. Since the glass transition or relaxation processes affect behavior of open spaces, one can study these phenomena through the detection of the open spaces using the positron annihilation technique. In the present paper, we report studies of the glass transition and relaxation processes in polyethylene, polypropylene, and polystyrene by measurements of lifetime spectra of positrons and those of Doppler broadening profiles of the annihilation radiation. For these specimens, by measurements of the lifetime of Ps, {tau}{sub 3}, as a function of temperature, the glass transition temperature, T{sub g}, was determined as an onset temperature of the increase in the temperature coefficient of {tau}{sub 3}. Below T{sub g}, local motions of molecules were detected by measurements of the formation probability of Ps. The positron annihilation as a tool for the characterization of polymers was discussed. (author). 51 refs.

  20. Growth and relaxation processes in Ge nanocrystals on free-standing Si(001) nanopillars.

    Science.gov (United States)

    Kozlowski, G; Zaumseil, P; Schubert, M A; Yamamoto, Y; Bauer, J; Schülli, T U; Tillack, B; Schroeder, T

    2012-03-23

    We study the growth and relaxation processes of Ge crystals selectively grown by chemical vapour deposition on free-standing 90 nm wide Si(001) nanopillars. Epi-Ge with thickness ranging from 4 to 80 nm was characterized by synchrotron based x-ray diffraction and transmission electron microscopy. We found that the strain in Ge nanostructures is plastically released by nucleation of misfit dislocations, leading to degrees of relaxation ranging from 50 to 100%. The growth of Ge nanocrystals follows the equilibrium crystal shape terminated by low surface energy (001) and {113} facets. Although the volumes of Ge nanocrystals are homogeneous, their shape is not uniform and the crystal quality is limited by volume defects on {111} planes. This is not the case for the Ge/Si nanostructures subjected to thermal treatment. Here, improved structure quality together with high levels of uniformity of the size and shape is observed.

  1. Evaluation of multi-exponential relaxation processes: In vitro and in vivo studies

    International Nuclear Information System (INIS)

    Henriksen, O.; Thomsen, C.; Kjaer, L.; Ring, P.

    1986-01-01

    T1 and T2 relaxation values obtained at 1.5 T were measured on 12 inversion-recovery (IR) sequences and a multiple spin-echo (SE) sequence with 32 echoes. Phantom studies were carried out for different CuSO/sub 4/ solutions, using MR imaging and reference spectrometry. The correlation was excellent (r=.98, P>.01;r=1.00, P>.01). T1 and T2 values varied less than 10% in the imaging plane. Then two-compartment phantoms were examined. For T1 and T2, the ratios T1(compartment A)/T1 (compartment B)>6 ant T2(c.A)/T2(c.B) > 6 were essential for reliable estimation. Studies on the normal brain indicate a multiexponential T1 and T2 relaxation process in gray matter

  2. Relaxation and excitation electronic processes in dielectrics irradiated by ultrafast IR and VUV pulses

    International Nuclear Information System (INIS)

    Gaudin, J.

    2005-11-01

    We studied excitation and relaxation of electrons involved during interaction of visible and VUV femtosecond pulses with dielectrics. The generated population of hot electrons, having energy of few eV to few tens of eV above the bottom of the conduction band, is responsible of phenomena ranging to defect creation to optical breakdown. Owing to two techniques: photoemission and transient photoconductivity we improve the understanding of the The first photoemission experiments deal with dielectrics irradiated by 30 fs IR pulses. The photoemission spectra measured show a large population of electrons which energy rise up to 40 eV. We interpret this result in terms of a new absorption process: direct multi-photons inter-branch transitions. The 2. type of photoemission experiments are time resolved 'pump/probe' investigation. We study the relaxation of electrons excited by a VUV pulses. We used the high order harmonics (HOH) as light sources. We found surprisingly long decay time in the range of ps timescale. Last type of experiments is photoconductivity studies of diamond samples. Using HOH as light source we measure the displacement current induced by excited electrons in the conduction band. Those electrons relax mainly by impact ionisation creating secondary electrons. Hence by probing the number of electrons we were able to measure the efficiency of these relaxation processes. We observe a diminution of this efficiency when the energy of exciting photons is above 20 eV. Owing to Monte-Carlo simulation we interpret this result in terms of band structure effect. (author)

  3. Simulation study of MHD relaxation and reconnection processes in RFP plasma

    International Nuclear Information System (INIS)

    Kusano, Kanya; Kunimoto, Kaito; Suzuki, Yoshio; Tamano, Teruo; Sato, Tetsuya

    1991-01-01

    The authors have studied several nonlinear processes in RFP plasma through the use of 3D MHD simulations. In particular, they have shed light on: (1) dynamo and self-sustainment in reversed-field pinch (RFP), (2) phase locking process in MHD relaxation, and (3) the heating and acceleration in magnetic reconnection process. First, the contributions of the kink (m = 1) mode (linearly unstable) and of the m = 0 mode (driven by nonlinear coupling) to the dynamo are qualitatively evaluated using a high accuracy simulation. It is found that, if the free energy to drive kink instabilities is as small as that in the actual experimental plasma, the m = 0 modes, driven nonlinearly, play a more important role for the flux generation than the kink modes. Secondly, numerical simulations of the self-sustainment process in a RFP are performed. It is confirmed that the self-sustainment process is a coherent oscillating process composed of the MHD relaxation and the resistive diffusion processes. Toroidal phase locking process of kink modes is numerically observed in simulations of self-reversal and self-sustainment processes. It has characteristics similar to the slinky mode observed in the OHTE experiment. A detailed investigation reveals that nonlinear coupling between the most unstable two kink modes governs the entire dynamics in all kink modes and leads to the phase locking process. They find that reconnection can accelerate plasma over a local Alfven speed. This is a result of the fact that the magnetic field in the downstream area plays a similar role to de Laval nozzle. They also investigate the heating mechanisms in reconnection process. It is revealed that the viscous heating rate is as large as the joule heating rate in the reconnection process. This result implies that the viscous heating in the reconnection process is an important candidate for the mechanism to explain the RFP experiments where the ion temperatures is higher than the electron temperature

  4. The study of magnetic properties and relaxation processes in Co/Au bimetallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hrubovčák, Pavol [Department of Condensed Matter Physics, P.J. Šafárik University, Park Angelinum 9, Košice (Slovakia); Zeleňáková, Adriana, E-mail: adriana.zelenakova@upjs.sk [Department of Condensed Matter Physics, P.J. Šafárik University, Park Angelinum 9, Košice (Slovakia); Zeleňák, Vladimir [Department of Inorganic Chemistry, P.J. Šafárik University, Moyzesova 11, Košice (Slovakia); Kováč, Jozef [Institute of Experimental Physics, SAS, Watsonova 41, Košice (Slovakia)

    2015-11-15

    Co/Au bimetallic fine nanoparticles were prepared employing the method of microemulsion using reverse micelle as nanoreactor, controlling the particles size. Magnetic and structural properties of two different samples Co/Au1 and Co/Au2 with almost comparable size of Co core and different size of Au layer were studied. The investigation of magnetic relaxation processes present in the particles was carried out by means of ac and dc magnetization data obtained at different temperatures and magnitudes of magnetic field. We observed the existence of superspin glass state characterized by the strong inter-particle interactions in the nanoparticle systems. In this paper, we discuss the attributes of novel superspin glass magnetic state reflected on various features (saturated FC magnetization at low temperatures, shift of the Cole–Cole arc downwards) and calculated parameters (relaxation time, critical exponent zv ∼ 10 and frequency dependent criterion p < 0.05). Comparison of the magnetic properties of two studied samples show that the thickness of diamagnetic Au shell significantly influences the magnetic interactions and change the relaxation dynamics. - Highlights: • Co/Au fine nanoparticles prepared by reverse micelle as nanoreactor, controlling the size. • Existence of superspin glass state confirmed from ac magnetic susceptibility study. • Individual particles exhibit the collective behavior below glass temperature T{sub SSG}. • Influence of diamagnetic shell on the magnetic properties of core–shell nanoparticles.

  5. Asymptotic description of two metastable processes of solidification for the case of large relaxation time

    International Nuclear Information System (INIS)

    Omel'yanov, G.A.

    1995-07-01

    The non-isothermal Cahn-Hilliard equations in the n-dimensional case (n = 2,3) are considered. The interaction length is proportional to a small parameter, and the relaxation time is proportional to a constant. The asymptotic solutions describing two metastable processes are constructed and justified. The soliton type solution describes the first stage of separation in alloy, when a set of ''superheated liquid'' appears inside the ''solid'' part. The Van der Waals type solution describes the free interface dynamics for large time. The smoothness of temperature is established for large time and the Mullins-Sekerka problem describing the free interface is derived. (author). 46 refs

  6. One and two-phonon processes of the spin-flip relaxation in quantum dots: Spin-phonon coupling mechanism

    Science.gov (United States)

    Wang, Zi-Wu; Li, Shu-Shen

    2012-07-01

    We investigate the spin-flip relaxation in quantum dots using a non-radiation transition approach based on the descriptions for the electron-phonon deformation potential and Fröhlich interaction in the Pavlov-Firsov spin-phonon Hamiltonian. We give the comparisons of the electron relaxations with and without spin-flip assisted by one and two-phonon processes. Calculations are performed for the dependence of the relaxation time on the external magnetic field, the temperature and the energy separation between the Zeeman sublevels of the ground and first-excited state. We find that the electron relaxation time of the spin-flip process is more longer by three orders of magnitudes than that of no spin-flip process.

  7. The relaxation time of processes in a FitzHugh-Nagumo neural system with time delay

    International Nuclear Information System (INIS)

    Gong Ailing; Zeng Chunhua; Wang Hua

    2011-01-01

    In this paper, we study the relaxation time (RT) of the steady-state correlation function in a FitzHugh-Nagumo neural system under the presence of multiplicative and additive white noises and time delay. The noise correlation parameter λ can produce a critical behavior in the RT as functions of the multiplicative noise intensity D, the additive noise intensity Q and the time delay τ. That is, the RT decreases as the noise intensities D and Q increase, and increases as the time delay τ increases below the critical value of λ. However, above the critical value, the RT first increases, reaches a maximum, and then decreases as D, Q and τ increase, i.e. a noise intensity D or Q and a time delay τ exist, at which the time scales of the relaxation process are at their largest. In addition, the additive noise intensity Q can also produce a critical behavior in the RT as a function of λ. The noise correlation parameter λ first increases the RT of processes, then decreases it below the critical value of Q. Above the critical value, λ increases it.

  8. Scope and limitations of due process in administrative proceedings

    Directory of Open Access Journals (Sweden)

    Bernardo Carvajal Sánchez

    2010-12-01

    Full Text Available In order to explain in a better way the scope of Due Process in Administrative Law as a legal norm whose respect is essential to all government agencies, three points of view (formal, structural and material are proposed. Those items seem useful to understand “Administrative Due Process” in all its dimensions: as a constitutional norm developed by the enactment of laws and decrees; as a principle inspiring some conducts and new norms; and as an objective and subjective fundamental right. On the other hand, it is shown that Administrative Due Process is not an absolute rule because in some cases its full application is subject to normative relativism. Two opposite trends can be perceived at this point: in the first place, government agencies usually do not act the same way judges do, so Administrative Due Process should be distinguished from Judicial Due Process; therefore, it could actually have a more restricted scope. In the second place, some administrative authorities are nowadays playing a role more or less similar to what judges do. This means that new procedural guarantees will be claimed. In any case, admitting valid limitations to Administrative Due Process leads to the quest of the limits of these limitations. The application of the rule of Due Process cannot be totally suppressed; its scope cannot be completely reduced. This is the result of its fundamental nature as a legal norm that ensures justice and equity in all administrative procedures, and proscribes random decisions.

  9. Relaxation processes in aqueous solutions upon X-ray exposure. Entanglement of electronic and nuclear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Unger, Isaak

    2017-07-01

    About a decade ago new types of electronic non-radiative relaxation processes, involving the environment of an electronically excited or ionized monomer, have been predicted for van der Waals clusters and these were also the first systems where such processes have been detected experimentally. These new autoionization channels encompass the recombination of an electron and a hole, and the energy transfer to a neighboring atom or molecule. Two processes can be distinguished here. In the intermolecular Coulombic decay (ICD) the hole created upon ionization of a monomer is filled by a valence electron of the same species, and the energy released in this electron-hole recombination is used to ionize a neighboring species. In the electron transfer mediated decay (ETMD) the initial hole is filled by an electron from a neighboring species, and the energy released by this recombination is either used to ionize the same neighbor species, or to ionize a third monomer. In more recent experiments on liquid water it has been discovered that these non- local autoionization processes are strongly coupled with ultrafast nuclear dynamics. The core ionization initiates proton motion along a hydrogen donor-bond of the electronically excited water cation. This nuclear dynamics leads to the formation of transient cationic species where a proton is shared by two neighboring water molecules. Subsequent autoionization, either via Auger decay, ICD or ETMD, then occurs from any of such structure transients. This relaxation process is termed proton transfer mediated charge separation, PTM-CS. It has been found in a number of experiments that the probability of PTM-CS to occur depends on the hydrogen-bond strength between the core-ionized molecule and solvent molecules.

  10. Understanding charge carrier relaxation processes in terbium arsenide nanoparticles using transient absorption spectroscopy

    Science.gov (United States)

    Vanderhoef, Laura R.

    Erbium arsenide nanoparticles epitaxially grown within III-V semiconductors have been shown to improve the performance of devices for applications ranging from thermoelectrics to THz pulse generation. The small size of rare-earth nanoparticles suggests that interesting electronic properties might emerge as a result of both spatial confinement and surface states. However, ErAs nanoparticles do not exhibit any signs of quantum confinement or an emergent bandgap, and these experimental observations are understood from theory. The incorporation of other rare-earth monopnictide nanoparticles into III-V hosts is a likely path to engineering carrier excitation, relaxation and transport dynamics for optoelectronic device applications. However, the electronic structure of these other rare-earth monopnictide nanoparticles remains poorly understood. The objective of this research is to explore the electronic structure and optical properties of III-V materials containing novel rare-earth monopnictides. We use ultrafast pump-probe spectroscopy to investigate the electronic structure of TbAs nanoparticles in III-V hosts. We start with TbAs:GaAs, which was expected to be similar to ErAs:GaAs. We study the dynamics of carrier relaxation into the TbAs states using optical pump terahertz probe transient absorption spectroscopy. By analyzing how the carrier relaxation rates depend on pump fluence and sample temperature, we conclude that the TbAs states are saturable. Saturable traps suggest the existence of a bandgap for TbAs nanoparticles, in sharp contrast with previous results for ErAs. We then apply the same experimental technique to two samples of TbAs nanoparticles in InGaAs with different concentrations of TbAs. We observe similar relaxation dynamics associated with trap saturation, though the ability to resolve these processes is contingent upon a high enough TbAs concentration in the sample. We have also constructed an optical pump optical probe transient absorption

  11. Influence of relaxation processes on the evaluation of the metastable defect density in Cu(In,Ga)Se{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Maciaszek, M.; Zabierowski, P. [Faculty of Physics, Warsaw University of Technology, Koszykowa 75, Warszawa 00 662 (Poland)

    2016-06-07

    In this contribution, we investigated by means of numerical simulations the influence of relaxation processes related to metastable defects on electrical characteristics of Cu(In,Ga)Se{sub 2}. In particular, we analyzed the relaxation of a metastable state induced by illumination at a fixed temperature as well as the dependence of the hole concentration on the temperature during cooling. The knowledge of these two relaxation processes is crucial in the evaluation of the hole concentration in the relaxed state and after light soaking. We have shown that the distribution of the metastable defects can be considered frozen below 200 K. The hole capture cross section was estimated as ∼3 × 10{sup −15} cm{sup 2}. It was shown that the usually used cooling rates may lead to relevant changes of the hole concentration. We calculated the lower limit of the hole concentration after cooling, and we presented how it depends on densities of shallow acceptors and metastable defects. Moreover, we proposed a method which allows for the evaluation of shallow acceptor and metastable defect densities from two capacitance-voltage profiles measured in the relaxed and light soaking states. Finally, we indicated experimental conditions in which the influence of relaxation processes on the accuracy of this method is the smallest.

  12. Diffusion processes in the relaxed cross sections for the reaction 107109Ag+20Ne

    International Nuclear Information System (INIS)

    Babinet, R.; Moretto, L.G.; Galin, J.; Jared, R.; Moulton, J.; Thompson, S.G.

    1976-01-01

    The fragments emitted in the reaction 107 109 Ag+ 20 Ne at 175 and 252 MeV bombarding energy have been identified in charge up to Z=32. Kinetic energy distributions, cross sections and angular distributions have been measured for each Z. The kinetic energy spectra show the two usual components: the quasielastic component and the relaxed component. The Z-distribution of the latter is fairly flat, slowly decreasing up to Z approximately 15 and then rising again up to Z=30. The variations in the Z-distribution are more pronounced at the lower bombarding energy. The angular distributions associated with the relaxed component are forward peaked for Z-values close to that of the projectile and behave like 1/sintheta for larger Z-values. The forward peaking is very substantial for Z 10 the forward peaking in excess of 1/sintheta disappears around Z=15. These features are interpreted in terms of a diffusion process along the asymmetry coordinate of a short-lived intermediate complex. (Auth.)

  13. In vivo measurements of relaxation process in the human liver by MRI. The role of respiratory gating/triggering

    DEFF Research Database (Denmark)

    Thomsen, C; Henriksen, O; Ring, P

    1988-01-01

    In vivo estimation of relaxation processes in the liver by magnetic resonance imaging (MRI) may be helpful for characterization of various pathological conditions in the liver. However, such measurements may be significantly hampered by movement of the liver with the respiration. The effect...... of synchronization of data acquisition to the respiratory cycle on measured T1- and T2-relaxation curves was studied in normal subjects, patients with diffuse liver disease, and patients with focal liver pathology. Multi spin echo sequences with five different repetition times were used. The measurements were...... carried out with and without respiratory gating/triggering. In the healthy subjects as well as in the patients with diffuse liver diseases respiratory synchronization did not alter the obtained relaxation curves. However, in the patients with focal pathology the relaxation curves were significantly...

  14. The due diligence process for acquiring and building power plants

    International Nuclear Information System (INIS)

    Vallen, M.A.; Bullinger, C.D.

    1999-01-01

    The restructuring of the electric generating business is continuing at a torrid pace. New auctions of generation portfolios are initiated almost monthly, and announcements of new development projects arrive almost daily. It has become imperative, then, that participants in both acquisitions and development projects become conversant with the necessary due diligence process, a complex and critical task that can mean the difference between success and failure. A thorough due diligence process allows bidder/developers to uncover value and quantify liabilities before bidding/building, translating into the best analysis possible and resulting in a winning investment decision. This article describes the process by which buyers and developers approach and manage the due diligence process as a key step in making their investment decision

  15. Rational extended thermodynamics of a rarefied polyatomic gas with molecular relaxation processes

    Science.gov (United States)

    Arima, Takashi; Ruggeri, Tommaso; Sugiyama, Masaru

    2017-10-01

    We present a more refined version of rational extended thermodynamics of rarefied polyatomic gases in which molecular rotational and vibrational relaxation processes are treated individually. In this case, we need a triple hierarchy of the moment system and the system of balance equations is closed via the maximum entropy principle. Three different types of the production terms in the system, which are suggested by a generalized BGK-type collision term in the Boltzmann equation, are adopted. In particular, the rational extended thermodynamic theory with seven independent fields (ET7) is analyzed in detail. Finally, the dispersion relation of ultrasonic wave derived from the ET7 theory is confirmed by the experimental data for CO2, Cl2, and Br2 gases.

  16. Investigation of transitions and relaxation processes in polystyrene by using positron annihilation

    International Nuclear Information System (INIS)

    Ban, M.; Kyoto, M.

    1996-01-01

    The glass transition and relaxation processes in polystyrene resins with the number average molecular weight ranging from 7.0 x 10 2 to 9.8 x 10 4 were studied with the positron annihilation technique. The pick-off annihilation lifetime of ortho-positronium (τ 3 ) and its intensity (Ι 3 ) were measured in the temperature range from 20 to 430 K. The glass transition temperature (Τ g ) was determined as an onset temperature coefficient of τ 3 x Τ g shows the molecular weight dependence in these samples. Below Τ g , local motions were detected by measurements of Ι 3 . The local motions could be observed above 100 K in this experiment. Ι 3 show the minimum at around 250 K and it does not show molecular weight dependence. (author)

  17. Investigations of effect of phase change mass transfer rate on cavitation process with homogeneous relaxation model

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhixia; Zhang, Liang; Saha, Kaushik; Som, Sibendu; Duan, Lian; Wang, Qian

    2017-12-01

    The super high fuel injection pressure and micro size of nozzle orifice has been an important development trend for the fuel injection system. Accordingly, cavitation transient process, fuel compressibility, amount of noncondensable gas in the fuel and cavitation erosion have attracted more attention. Based on the fact of cavitation in itself is a kind of thermodynamic phase change process, this paper takes the perspective of the cavitation phase change mass transfer process to analyze above mentioned phenomenon. The two-phase cavitating turbulent flow simulations with VOF approach coupled with HRM cavitation model and U-RANS of standard k-ε turbulence model were performed for investigations of cavitation phase change mass transfer process. It is concluded the mass transfer time scale coefficient in the Homogenous Relaxation Model (HRM) representing mass transfer rate should tend to be as small as possible in a condition that ensured the solver stable. At very fast mass transfer rate, the phase change occurs at very thin interface between liquid and vapor phase and condensation occurs more focused and then will contribute predictably to a more serious cavitation erosion. Both the initial non-condensable gas in fuel and the fuel compressibility can accelerate the cavitation mass transfer process.

  18. Anomalous relaxation and self-organization in non-equilibrium processes

    OpenAIRE

    Fatkullin, Ibrahim; Kladko, Konstantin; Mitkov, Igor; Bishop, A. R.

    2000-01-01

    We study thermal relaxation in ordered arrays of coupled nonlinear elements with external driving. We find, that our model exhibits dynamic self-organization manifested in a universal stretched-exponential form of relaxation. We identify two types of self-organization, cooperative and anti-cooperative, which lead to fast and slow relaxation, respectively. We give a qualitative explanation for the behavior of the stretched exponent in different parameter ranges. We emphasize that this is a sys...

  19. Relaxation System

    Science.gov (United States)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  20. Sensitivity of Process Design due to Uncertainties in Property Estimates

    DEFF Research Database (Denmark)

    Hukkerikar, Amol; Jones, Mark Nicholas; Sarup, Bent

    2012-01-01

    The objective of this paper is to present a systematic methodology for performing analysis of sensitivity of process design due to uncertainties in property estimates. The methodology provides the following results: a) list of properties with critical importance on design; b) acceptable levels of...... in chemical processes. Among others vapour pressure accuracy for azeotropic mixtures is critical and needs to be measured or estimated with a ±0.25% accuracy to satisfy acceptable safety levels in design....

  1. 34 CFR 300.508 - Due process complaint.

    Science.gov (United States)

    2010-07-01

    ... attending; (5) A description of the nature of the problem of the child relating to the proposed or refused initiation or change, including facts relating to the problem; and (6) A proposed resolution of the problem... section, the hearing officer must make a determination on the face of the due process complaint of whether...

  2. "Ingraham v. Wright" and the Decline of Due Process.

    Science.gov (United States)

    Clark, Gerard J.

    1978-01-01

    Suggests that the constitutional questions in "Ingraham vs Wright" lend credence to a concern that the Court is seeking to eliminate all due process intervention outside of the incorporation and privacy cases and to limit even these cases to defenses of a criminal prosecution. Available from Suffolk University Law Review Office, 41…

  3. Teaching about Due Process of Law. ERIC Digest.

    Science.gov (United States)

    Vontz, Thomas S.

    Fundamental constitutional and legal principles are central to effective instruction in the K-12 social studies curriculum. To become competent citizens, students need to develop an understanding of the principles on which their society and government are based. Few principles are as important in the social studies curriculum as due process of…

  4. Basic Substantive Law for Paralegals: Contracts, Torts, and Due Process.

    Science.gov (United States)

    Marcin, Raymond B.

    Part of the paralegal, or legal assistant, training materials prepared by the National Paralegal Institution under a Federal grant, the text comprises an overview of the basic legal concepts usually found in introductory law courses concerning contracts, torts, and the due process area of constitutional law. Part 1, Contracts, covers: definition,…

  5. Measured spatial variability of beach erosion due to aeolian processes.

    NARCIS (Netherlands)

    de Vries, S.; Verheijen, A.H.; Hoonhout, B.M.; Vos, S.E.; Cohn, Nicholas; Ruggiero, P; Aagaard, T.; Deigaard, R.; Fuhrman, D.

    2017-01-01

    This paper shows the first results of measured spatial variability of beach erosion due to aeolian processes during the recently conducted SEDEX2 field experiment at Long Beach, Washington, U.S.A.. Beach erosion and sedimentation were derived using series of detailed terrestrial LIDAR measurements

  6. Relaxation of Isolated Ventricular Cardiomyocytes by a Voltage-Dependent Process

    Science.gov (United States)

    Bridge, John H. B.; Spitzer, Kenneth W.; Ershler, Philip R.

    1988-08-01

    Cell contraction and relaxation were measured in single voltage-clamped guinea pig cardiomyocytes to investigate the contribution of sarcolemmal Na+-Ca2+ exchange to mechanical relaxation. Cells clamped from -80 to 0 millivolts displayed initial phasic and subsequent tonic contractions; caffeine reduced or abolished the phasic and enlarged the tonic contraction. The rate of relaxation from tonic contractions was steeply voltage-dependent and was significantly slowed in the absence of a sarcolemmal Na+ gradient. Tonic contractions elicited in the absence of a Na+ gradient promptly relaxed when external Na+ was applied, reflecting activation of Na+-Ca2+ exchange. It appears that a voltage-dependent Na+-Ca2+ exchange can rapidly mechanically relax mammalian heart muscle.

  7. The role of non-equilibrium fluxes in the relaxation processes of the linear chemical master equation.

    Science.gov (United States)

    de Oliveira, Luciana Renata; Bazzani, Armando; Giampieri, Enrico; Castellani, Gastone C

    2014-08-14

    We propose a non-equilibrium thermodynamical description in terms of the Chemical Master Equation (CME) to characterize the dynamics of a chemical cycle chain reaction among m different species. These systems can be closed or open for energy and molecules exchange with the environment, which determines how they relax to the stationary state. Closed systems reach an equilibrium state (characterized by the detailed balance condition (D.B.)), while open systems will reach a non-equilibrium steady state (NESS). The principal difference between D.B. and NESS is due to the presence of chemical fluxes. In the D.B. condition the fluxes are absent while for the NESS case, the chemical fluxes are necessary for the state maintaining. All the biological systems are characterized by their "far from equilibrium behavior," hence the NESS is a good candidate for a realistic description of the dynamical and thermodynamical properties of living organisms. In this work we consider a CME written in terms of a discrete Kolmogorov forward equation, which lead us to write explicitly the non-equilibrium chemical fluxes. For systems in NESS, we show that there is a non-conservative "external vector field" whose is linearly proportional to the chemical fluxes. We also demonstrate that the modulation of these external fields does not change their stationary distributions, which ensure us to study the same system and outline the differences in the system's behavior when it switches from the D.B. regime to NESS. We were interested to see how the non-equilibrium fluxes influence the relaxation process during the reaching of the stationary distribution. By performing analytical and numerical analysis, our central result is that the presence of the non-equilibrium chemical fluxes reduces the characteristic relaxation time with respect to the D.B. condition. Within a biochemical and biological perspective, this result can be related to the "plasticity property" of biological systems and to their

  8. The role of non-equilibrium fluxes in the relaxation processes of the linear chemical master equation

    International Nuclear Information System (INIS)

    Oliveira, Luciana Renata de; Bazzani, Armando; Giampieri, Enrico; Castellani, Gastone C.

    2014-01-01

    We propose a non-equilibrium thermodynamical description in terms of the Chemical Master Equation (CME) to characterize the dynamics of a chemical cycle chain reaction among m different species. These systems can be closed or open for energy and molecules exchange with the environment, which determines how they relax to the stationary state. Closed systems reach an equilibrium state (characterized by the detailed balance condition (D.B.)), while open systems will reach a non-equilibrium steady state (NESS). The principal difference between D.B. and NESS is due to the presence of chemical fluxes. In the D.B. condition the fluxes are absent while for the NESS case, the chemical fluxes are necessary for the state maintaining. All the biological systems are characterized by their “far from equilibrium behavior,” hence the NESS is a good candidate for a realistic description of the dynamical and thermodynamical properties of living organisms. In this work we consider a CME written in terms of a discrete Kolmogorov forward equation, which lead us to write explicitly the non-equilibrium chemical fluxes. For systems in NESS, we show that there is a non-conservative “external vector field” whose is linearly proportional to the chemical fluxes. We also demonstrate that the modulation of these external fields does not change their stationary distributions, which ensure us to study the same system and outline the differences in the system's behavior when it switches from the D.B. regime to NESS. We were interested to see how the non-equilibrium fluxes influence the relaxation process during the reaching of the stationary distribution. By performing analytical and numerical analysis, our central result is that the presence of the non-equilibrium chemical fluxes reduces the characteristic relaxation time with respect to the D.B. condition. Within a biochemical and biological perspective, this result can be related to the “plasticity property” of biological

  9. Dynamic relaxation processes in compressible multiphase flows. Application to evaporation phenomena

    Directory of Open Access Journals (Sweden)

    Le Métayer O.

    2013-07-01

    Full Text Available Phase changes and heat exchanges are examples of physical processes appearing in many industrial applications involving multiphase compressible flows. Their knowledge is of fundamental importance to reproduce correctly the resulting effects in simulation tools. A fine description of the flow topology is thus required to obtain the interfacial area between phases. This one is responsible for the dynamics and the kinetics of heat and mass transfer when evaporation or condensation occurs. Unfortunately this exchange area cannot be obtained easily and accurately especially when complex mixtures (drops, bubbles, pockets of very different sizes appear inside the transient medium. The natural way to solve this specific trouble consists in using a thin grid to capture interfaces at all spatial scales. But this possibility needs huge computing resources and can be hardly used when considering physical systems of large dimensions. A realistic method is to consider instantaneous exchanges between phases by the way of additional source terms in a full non-equilibrium multiphase flow model [2,15,17]. In this one each phase obeys its own equation of state and has its own set of equations and variables (pressure, temperature, velocity, energy, entropy,.... When enabling the relaxation source terms the multiphase mixture instantaneously tends towards a mechanical or thermodynamic equilibrium state at each point of the flow. This strategy allows to mark the boundaries of the real flow behavior and to magnify the dominant physical effects (heat exchanges, evaporation, drag,... inside the medium. A description of the various relaxation processes is given in the paper. Les changements de phase et les transferts de chaleur sont des exemples de phénomènes physiques présents dans de nombreuses applications industrielles faisant intervenir des écoulements compressibles multiphasiques. La connaissance des mécanismes associés est primordiale afin de reproduire

  10. Dual-resonances approach to broadband cavity-assisted optical signal processing beyond the carrier relaxation rate

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Mørk, Jesper

    2014-01-01

    We propose and analyze a differential control scheme for cavity-enhanced optical signal processing devices based on carrier nonlinearities. The scheme relies on two optical cavities to increase the bandwidth beyond the limit given by the slowest carrier relaxation rate of the medium. Practical...

  11. Relaxation of the lower frit loading constraint for DWPF process control

    International Nuclear Information System (INIS)

    Brown, K.G.

    2000-01-01

    The lower limit on the frit loading parameter when measurement uncertainty is introduced has impacted DWPF performance during immobilization of Tank 42 Sludge; therefore, any defensible relaxation or omission of this constraint should correspondingly increase DWPF waste loading and efficiency. Waste loading should be increased because the addition of frit is the current remedy for exceeding the lower frit loading constraint. For example, frit was added to DWPF SME Batches 94, 97 and 98 to remedy these batches for low frit loading. Attempts were also made to add frit in addition to the optimum computed to assure the lower frit loading constraint would be satisfied; however, approximately half of the SME Batches produced after Batch 98 have violated the lower frit loading constraint. If the DWPF batches did not have to be remediated and additional frit added because of the lower frit loading limit, then both, the performance of the DWPF process and the waste loading in the glass produced would be increased. Before determining whether or not the lower frit loading limit can be relaxed or omitted, the origin of this and the other constraints related to durability prediction must be examined. The lower limit loading constraint results from the need to make highly durable glass in DWPF. It is required that DWPF demonstrate that the glass produced would have durability that is at least two standard deviations greater than that of the Environmental Assessment (EA) glass. Glass durability cannot be measured in situ, it must be predicted from composition which can be measured. Fortunately, the leaching characteristics of homogeneous waste glasses is strongly related to the total molar free energy of the constituent species. Thus the waste acceptance specification has been translated into a requirement that the total molar free energy associated with the glass composition that would be produced from a DWPF melter feed batch be less than that of the EA glass accounting for

  12. Cellular Particle Dynamics simulation of biomechanical relaxation processes of multi-cellular systems

    Science.gov (United States)

    McCune, Matthew; Kosztin, Ioan

    2013-03-01

    Cellular Particle Dynamics (CPD) is a theoretical-computational-experimental framework for describing and predicting the time evolution of biomechanical relaxation processes of multi-cellular systems, such as fusion, sorting and compression. In CPD, cells are modeled as an ensemble of cellular particles (CPs) that interact via short range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through numerical integration of their equations of motion. Here we present CPD simulation results for the fusion of both spherical and cylindrical multi-cellular aggregates. First, we calibrate the relevant CPD model parameters for a given cell type by comparing the CPD simulation results for the fusion of two spherical aggregates to the corresponding experimental results. Next, CPD simulations are used to predict the time evolution of the fusion of cylindrical aggregates. The latter is relevant for the formation of tubular multi-cellular structures (i.e., primitive blood vessels) created by the novel bioprinting technology. Work supported by NSF [PHY-0957914]. Computer time provided by the University of Missouri Bioinformatics Consortium.

  13. Relaxation of Si-SiO2 interfacial stress in bipolar screen oxides due to ionizing radiation

    International Nuclear Information System (INIS)

    Witczak, S.C.; Galloway, K.F.; Schrimpf, R.D.; Suehle, J.S.

    1995-01-01

    Current gain degradation due to ionizing radiation in complementary single-crystalline emitter bipolar transistors was found to grow progressively worse upon subjecting the transistors to repeated cycles of radiation exposure and high-temperature anneal. The increase in radiation sensitivity is independent of the emitter polarity or geometry and is most dramatic between the first and second radiation and anneal cycles. In parallel with the current gain measurements, samples from a monitor wafer simulating the screen oxide region above the extrinsic base in the npn transistors were measured for mechanical stress while undergoing similar cycles of irradiation and anneal. The oxide on the monitor wafer consisted of a 45 nm thermal layer and a 640 nm deposited layer. The results indicate that ionizing radiation helped relieve compressive stress at the Si surface. The magnitude of the stress change due to radiation is smaller than the stress induced by the emitter contact metallization followed by a post-metallization anneal. Correlation of radiation sensitivity in the bipolar transistors and mechanical stress in the monitor wafer suggests that mechanical stress may be influential in determining the radiation hardness of bipolar transistors and lends validation to previously reported observations that Si-SiO 2 interfaces are increasingly more susceptible to radiation damage with decreasing Si compressive stress. Possible mechanisms for the observed changes in stress and their effect on the radiation sensitivity of the bipolar transistors are discussed

  14. Vib--rotational energy distributions and relaxation processes in pulsed HF chemical lasers

    International Nuclear Information System (INIS)

    Ben-Shaul, A.; Kompa, K.L.; Schmailzl, U.

    1976-01-01

    The rate equations governing the temporal evolution of photon densities and level populations in pulsed F+H 2 →HF+H chemical lasers are solved for different initial conditions. The rate equations are solved simultaneously for all relevant vibrational--rotational levels and vibrational--rotational P-branch transitions. Rotational equilibrium is not assumed. Approximate expressions for the detailed state-to-state rate constants corresponding to the various energy transfer processes (V--V, V--R,T, R--R,T) coupling the vib--rotational levels are formulated on the basis of experimental data, approximate theories, and qualitative considerations. The main findings are as follows: At low pressures, R--T transfer cannot compete with the stimulated emission, and the laser output largely reflects the nonequilibrium energy distribution in the pumping reaction. The various transitions reach threshold and decay almost independently and simultaneous lasing on several lines takes place. When a buffer gas is added in excess to the reacting mixture, the enhanced rotational relaxation leads to nearly single-line operation and to the J shift in lasing. Laser efficiency is higher at high inert gas pressures owing to a better extraction of the internal energy from partially inverted populations. V--V exchange enhances lasing from upper vibrational levels but reduces the total pulse intensity. V--R,T processes reduce the efficiency but do not substantially modify the spectral output distribution. The photon yield ranges between 0.4 and 1.4 photons/HF molecule depending on the initial conditions. Comparison with experimental data, when available, is fair

  15. Synergic nature of dielectric relaxation process in the layered perovskite halide salts: The case of 1,3- diammoniumpropylenetetrabromocadmate compound

    Science.gov (United States)

    Staśkiewicz, Beata

    2018-06-01

    The negative thermal expansion (NTE) property was a prototype to discuss the origin of difference between classical Debye relaxation process and the non-Debye behavior in the layered perovskite halide salt of chemical formula NH3(CH2)3NH3CdBr4. The analysis has been taken by dielectric relaxation spectroscopy measurements in almost six decades in frequency 5 × 102 ≤ f(ω) ≤ 1.2 × 108 and in the temperature range 315 ≤ T(K) ≤ 390. It was shown that the investigated sample exhibit an antiferrodistortive nature of phase transition between two orthorhombic structural modifications i.e. Pnma (phase I) and Ima2 (phase II) at Tc1(I → II) = 326 K, leading from an antiferroelectric to a paraelectric phase. The involvement of an odd number of carbon atoms in the alkylammonium chains in dielectric properties of examined sample is proved. Higher structural modifications, i.e. Ima2 (phase II) and P21/m (phase III), have shown significant deviations from a regular circle on the Cole-Cole diagram. Presented experimental observations are essentially important for the theoretical explanation of relaxation processes in analyzed organic - inorganic compound crystallizing in a perovskite-like topology and may provide new perspective on the fundamental aspect of relaxation response in "diammonium" series.

  16. Electronic relaxation processes in polyatomic molecules. Progress report, October 1, 1975--September 30, 1976

    International Nuclear Information System (INIS)

    Lim, E.C.

    1976-09-01

    Excitation energy dependence of radiationless decay rate under collision-free conditions was utilized as a probe of intramolecular vibrational relaxation in tetracene and pentacene. The results give evidence of vibrational relaxation which competes with electronic relaxation. The substitution dependence of T 1 (nπ*) → S 0 radiationless transition in monocyclic diazines and the temperature dependence of S 1 non-radiative decay rate in alcoholic solutions of polycyclic monoazines indicate that the vibronic interaction between the lowest energy nπ* and ππ* states leads to a rapid radiationless deactivation of the lower of the two electronic states. Finally, a photon-counting spectrofluorometer of very high sensitivity was constructed, and it was used to record T 2 → T 1 fluorescence in bromoanthracenes and S 2 → S 1 fluorescence in azulene. These spectra represent the first bona-fide, or the most convincing, observation of fluorescence between excited electronic states

  17. About relaxation phenomena and transport processing in a fully ionized non-ideal plasma

    International Nuclear Information System (INIS)

    Baimbetov, F.B.; Iztleuov, N.T.

    1999-01-01

    In this report correlation effects for non-ideal plasma are accounted in the so called pseudopotentials. The accounting of high order correlation influences in the pseudopotential lead to the strongly screened potential. Kinetic equation with pseudopotential is cited. The equations which describe the relaxation of the difference of directed velocities of plasma particles, and frequency of particle collision which determines relaxation of temperature for non-ideal plasma are obtained. On basis of mentioned kinetic equation the transport equation is obtained as well

  18. Ultrafast Physics Behind the Nonradiative Relaxation Process of Chromium Ions in Forsterite Crystals.

    Science.gov (United States)

    Demos, Stavros Gregorios

    The nonradiative relaxation following photoexcitation has been studied in Cr^{4+} -doped forsterite (Mg_2SiO _4) using picosecond laser excitation and ultrasensitive photon counting detection. The experimental techniques utilized were time resolved antiStokes Raman scattering and up-converted hot and ordinary luminescence. The up-converted hot luminescence technique allowed the investigation of the upper state nonradiative relaxation of the excited state manifold of Cr^{4+ }-doped forsterite. The excitation involves the absorption of two photons per photoexcited ion in a two-step absorption. Discrete peaks are observed in the hot up-converted luminescence spectrum and are attributed to the population of nonequilibrium vibronic levels during the deexcitation of the ions by phonon emission. This work reveals that the phonon modes participating in the initial steps of the nonradiative relaxation of the photoexcited ions have energies 218 +/- 20, 325 +/- 20, 365 +/- 20 and 513 +/- 12 cm^ {-1}. The shape of the luminescence spectral envelope suggests two electronic bottlenecks at ~2.1 and ~2.45 eV associated with slower rates of vibrational relaxation at different parts of the excited state manifold. Time resolved measurements indicated that the average time for phonon emission is of the order of hundreds of fs. Information on the nonequilibrium phonon dynamics of the 225, 335 and 370 cm^{-1} modes of forsterite has been obtained using time resolved Raman scattering. Laser pulses of 450 fs in duration and 590 nm in wavelength were used to excite the Cr ions 2.1 eV above the ground state. The probe pulses (obtained from the same laser) are monitoring the nonequilibrium phonon population through the intensity of the antiStokes Raman lines at various pump-probe delay times. Experiments were performed at room and liquid nitrogen temperatures. The observed nonequilibrium phonon populations are associated with the overall complex nonradiative decay following the excitation of

  19. Study of conduction mechanisms and relaxation processes in NiCl2-PVA composites

    International Nuclear Information System (INIS)

    Basha, A.F.; Amin, M.; Abdel Samad, H.A.

    1985-07-01

    Electric conduction measurements were made at different temperatures and fields on thin films NiCl 2 -PVA composites prepared by casting. The conduction is assumed to be generally ionic in nature and polarization contribution is suggested to operate mainly at higher temperatures. Space-charge limited conduction and relaxation phenomena have been observed. The obtained results made it possible to determine a complete set of conduction parameters including carrier mobility, carrier concentration, traps density, Fermi energy, activation energy, etc. (author)

  20. Anomalous diffusion due to hindering by mobile obstacles undergoing Brownian motion or Orstein-Ulhenbeck processes.

    Science.gov (United States)

    Berry, Hugues; Chaté, Hugues

    2014-02-01

    In vivo measurements of the passive movements of biomolecules or vesicles in cells consistently report "anomalous diffusion," where mean-squared displacements scale as a power law of time with exponent αmovement hindrance by obstacles is often invoked. However, our understanding of how hindered diffusion leads to subdiffusion is based on diffusion amidst randomly located immobile obstacles. Here, we have used Monte Carlo simulations to investigate transient subdiffusion due to mobile obstacles with various modes of mobility. Our simulations confirm that the anomalous regimes rapidly disappear when the obstacles move by Brownian motion. By contrast, mobile obstacles with more confined displacements, e.g., Orstein-Ulhenbeck motion, are shown to preserve subdiffusive regimes. The mean-squared displacement of tracked protein displays convincing power laws with anomalous exponent α that varies with the density of Orstein-Ulhenbeck (OU) obstacles or the relaxation time scale of the OU process. In particular, some of the values we observed are significantly below the universal value predicted for immobile obstacles in two dimensions. Therefore, our results show that subdiffusion due to mobile obstacles with OU type of motion may account for the large variation range exhibited by experimental measurements in living cells and may explain that some experimental estimates are below the universal value predicted for immobile obstacles.

  1. Mechanical relaxation in glasses

    International Nuclear Information System (INIS)

    Hiki, Y.

    2004-01-01

    The basic properties of glasses and the characteristics of mechanical relaxation in glasses were briefly reviewed, and then our studies concerned were presented. Experimental methods adopted were viscosity, internal friction, ultrasonic attenuation, and Brillouin scattering measurements. The specimens used were several kinds of inorganic, organic, and metallic glasses. The measurements were mainly carried out from the room temperature up to the glass transition temperature, and the relaxation time was determined as a function of temperature. The 'double relaxation' composed of two Arrhenius-type relaxations was observed in many materials. In both relaxations, the 'compensation effect' showing a correlation of the pre-exponential factor and the activation energy was observed. These results were explained by considering the 'complex relaxation' due to cooperative motions of atoms or group of atoms. Values of activation energy near the glass transition determined by the various experimental methods were compared with each other

  2. Process of optical excitation and relaxation of color center in synthetic diamond and its application to optoelectronics

    International Nuclear Information System (INIS)

    Nishida, Yoshio

    1989-01-01

    Irradiation of high-pressure synthesized diamond is carried out by using a nuclear reactor or a linac. Then, the effect of annealing on the color centers is observed. A study is made to identify different color centers and to provide techniques to control their introduction. Investigations cover the relation of color center formation with annealing temperature, dependence of color center formation on radiation dose, migration of H3 center and hydrogen, and applicability of five different color centers to optoelectronics. Next, a study is made of the formation and relaxation of the nitrogen vacancy (NV) center in a metastable excited state produced by optical excitation. An optical gain is essential to provide laser. Optical amplification is measured at the vibronic emission band of the NV center. An increase in absorption is detected, indicating that the NV center will not provide laser. In the optical excitation-relaxation process, the relaxation proceeds via a metastable state. Finally, hole burning of ZPL of the NV center is observed in the temperature range from 20K to 80K, and some of its features are described. (N.K.)

  3. Quantum process tomography with informational incomplete data of two J-coupled heterogeneous spins relaxation in a time window much greater than T1

    Science.gov (United States)

    Maciel, Thiago O.; Vianna, Reinaldo O.; Sarthour, Roberto S.; Oliveira, Ivan S.

    2015-11-01

    We reconstruct the time dependent quantum map corresponding to the relaxation process of a two-spin system in liquid-state NMR at room temperature. By means of quantum tomography techniques that handle informational incomplete data, we show how to properly post-process and normalize the measurements data for the simulation of quantum information processing, overcoming the unknown number of molecules prepared in a non-equilibrium magnetization state (Nj) by an initial sequence of radiofrequency pulses. From the reconstructed quantum map, we infer both longitudinal (T1) and transversal (T2) relaxation times, and introduce the J-coupling relaxation times ({T}1J,{T}2J), which are relevant for quantum information processing simulations. We show that the map associated to the relaxation process cannot be assumed approximated unital and trace-preserving for times greater than {T}2J.

  4. Influence of Na doping on the magnetic relaxation processes of magnetite

    International Nuclear Information System (INIS)

    Torres, C.; Arias, A. Gonzalez; Hisatake, K.; Francisco, C. de; Hernandez-Gomez, P.; Kim, C.O.; Kim, D.J.

    2007-01-01

    The relaxation of the initial magnetic permeability was measured in polycrystalline Na-doped magnetite samples, with nominal composition Na x Fe 3- x O 4 (x ranging from 0 to 0.05), by means of the magnetic disaccommodation (DA) technique. We found that the increasing amount of Na ions modifies the DA spectra and a very different behaviour depending on the sintering atmosphere. These results were discussed in terms of the presence of Na ions in the magnetite lattice, giving rise to certain modifications in their neighbourhood

  5. On thermodynamics of relaxation and creep processes in the theory of viscoelastic materials with fading memory

    International Nuclear Information System (INIS)

    Paglietti, A.

    1978-01-01

    This paper is concerned with the thermodynamical theory of materials with fading memory exhibiting the creep and relaxation properties. It is shown that, once the current thermodynamical approach is followed, the second principle of thermodynamics implies for these materials further restrictions on the free-energy functional in addition to the well-known ones deduced in the general theory of materials with fading memory. The possibility of an experimental check of the current approach and the possibility of an alternative and more general approach are briefly discussed. (author)

  6. Self-similarly evolving and minimally dissipated stable states of plasmas realized after relaxation and self-organization processes

    International Nuclear Information System (INIS)

    Kondoh, Yoshiomi; Hakoiwa, Toru; Okada, Akihito; Kobayashi, Naohiro; Takahashi, Toshiki

    2006-01-01

    A novel set of simultaneous eigenvalue equations having dissipative terms are derived to find self-similarly evolving and minimally dissipated stable states of plasmas realized after relaxation and self-organization processes. By numerically solving the set of eigenvalue equations in a cylindrical model, typical spatial profiles of plasma parameters, electric and magnetic fields and diffusion factors are presented, all of which determine self-consistently with each other by physical laws and mutual relations among them, just as in experimental plasmas. (author)

  7. Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass

    International Nuclear Information System (INIS)

    Yamaguchi, M.; Saito, K.; Ikushima, A.J.

    2002-01-01

    The defect centers induced by ArF laser irradiation in Ge-doped SiO 2 have been investigated by the electron-spin resonance method. In order to observe formation and relaxation processes of the defects, step annealing has been carried out after the irradiation at 77 K. The thermally induced decay of the self-trapped hole (STH) and formation of the so-called Ge(2) centers have been observed with increasing temperature. The result suggests that the holes are transferred from the STH to the Ge(2)

  8. Study of relaxation processes and uniaxial anisotropy in the Europium Gallium Garnet epitaxial films

    International Nuclear Information System (INIS)

    Mukhopadhyay, P.

    1987-04-01

    We report here the magnetic properties of Europium-Gallium Garnet LPE films of the type Eu x Y 3-x Fe 5-y Ga y O 12 (where O< x<1.2 and 1< y<1.1). The mechanism by which the magnetic moments relax in Eu or Sm Garnets is still not fully understood. We have made studies on Eu-Ga garnet films and explain some of the results observed in these films. Pb and Pt ions are always found as impurities in our films. Pb ions contribute to the anisotropy in the film. Most of the experimental results can be explained with the three sub lattice model. The shape of the FMR line width shows strong sensitivity towards the surface impurities. (author). 18 refs, 6 figs, 1 tab

  9. Modeling and simulation of the deposition/relaxation processes of polycrystalline diatomic structures of metallic nitride films

    Science.gov (United States)

    García, M. F.; Restrepo-Parra, E.; Riaño-Rojas, J. C.

    2015-05-01

    This work develops a model that mimics the growth of diatomic, polycrystalline thin films by artificially splitting the growth into deposition and relaxation processes including two stages: (1) a grain-based stochastic method (grains orientation randomly chosen) is considered and by means of the Kinetic Monte Carlo method employing a non-standard version, known as Constant Time Stepping, the deposition is simulated. The adsorption of adatoms is accepted or rejected depending on the neighborhood conditions; furthermore, the desorption process is not included in the simulation and (2) the Monte Carlo method combined with the metropolis algorithm is used to simulate the diffusion. The model was developed by accounting for parameters that determine the morphology of the film, such as the growth temperature, the interacting atomic species, the binding energy and the material crystal structure. The modeled samples exhibited an FCC structure with grain formation with orientations in the family planes of , and . The grain size and film roughness were analyzed. By construction, the grain size decreased, and the roughness increased, as the growth temperature increased. Although, during the growth process of real materials, the deposition and relaxation occurs simultaneously, this method may perhaps be valid to build realistic polycrystalline samples.

  10. The effects of progressive muscular relaxation as a nursing procedure used for those who suffer from stress due to multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Paolla Gabrielle Nascimento Novais

    Full Text Available ABSTRACT Objective: to evaluate the effect of progressive muscle relaxation as a nursing procedure on the levels of stress for sufferers of multiple sclerosis. Method: random clinical trials conducted at the Neurology outpatients unit at a University Hospital. The sample consisted of 40 patients who were being monitored as outpatients (20 in a control group and 20 in an experimental group. The Progressive Muscle Relaxation technique was used. The control variables were collected through interviews that were recorded on forms and on the Perceived Stress Scale that we used. Five meetings were held every fortnight covering a period of eight weeks. The experimental group was advised to carry out daily progressive muscle relaxation activities. After eight weeks of these activities, they were evaluated again to measure their levels of stress. In order to analyze the data used, the software package Statistics for Social Sciences version 19.0 was used. Results: the application of the t test showed a significant reduction in the Perceived Stress Scale scores in the experimental group (p<0.001, which in turn proved that there was a reduction in the levels of stress after the application of the relaxation practic-es. Conclusion: the progressive muscle relaxation activities contributed to the reduction in stress levels for multiple sclerosis suffers and thus can be used in nursing for patients. Clinical Trials Identifier: NCT 02673827.

  11. Effects due to spectator interaction in deep inelastic processes

    International Nuclear Information System (INIS)

    Smilga, A.V.

    1979-01-01

    The simplest diagrams describing interaction with the spectator in the e - π→e - + hadrons deep inelastic process are considered. The contribution of the final state interaction diagram to the structure function considerable in the Feynman gauge is suppressed under the temporal gauge choice in accordance with the results of the naive parton model. The expressin for the cross section of the process when large quark momentum is transferred to the spectator is derived

  12. Relaxation dynamics of the conductive processes for PbNb2O6 ferroelectric ceramics in the frequency and time domain

    International Nuclear Information System (INIS)

    Gonzalez, R L; Leyet, Y; Guerrero, F; Guerra, J de Los S; Venet, M; Eiras, J A

    2007-01-01

    The relaxation dynamics of the conductive process present in PbNb 2 O 6 piezoelectric ceramics was investigated. A relaxation function in the time domain, Φ(t), was found from the frequency dependence of the dielectric modulus (imaginary component, M'') by using a relaxation function in the frequency domain, F*(ω). The best relaxation function, F*(ω), was found to be a Cole-Cole distribution function, in which relaxation characteristic parameters, such as α and τ CC , are involved. On the other hand, the relaxation function, Φ(t), obtained by the time domain method, was found to be a Kohlrausch-Williams-Watts (KWW) function type. The thermal evolution of the characteristics parameters of the KWW function (β and τ*) was analysed. The values of the activation energy (E a ), obtained in the whole investigated temperature interval, suggest the existence of a relaxation mechanism (a conductive process), which may be interpreted by an ion hopping between neighbouring sites within the crystalline lattice. The results are corroborated with the formalism of the AC conductivity

  13. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    International Nuclear Information System (INIS)

    Sandoval-Pineda, J M; Garcia-Lira, J; Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R

    2009-01-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  14. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Pineda, J M; Garcia-Lira, J [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de IngenierIa Mecanica y Electrica (ESIME), Unidad profesional, Azcapotzalco, Av. de las Granjas No. 682, Col. Sta. Catarina Azcapotzalco, C.P. 02550, Mexico D.F. Mexico (Mexico); Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R, E-mail: jsandovalp@ipn.m, E-mail: guiurri@hotmail.co [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de IngenierIa Mecanica y Electrica (ESIME). Edificio 5. 2do Piso, Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, C.P. 07738, Mexico, D.F. Mexico (Mexico)

    2009-08-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  15. Super-Penrose process due to collisions inside ergosphere

    Science.gov (United States)

    Zaslavskii, O. B.

    If two particles collide inside the ergosphere, the energy in the center of mass frame can be made unbound provided at least one of particles has a large negative angular momentum [A. A. Grib and Yu. V. Pavlov, Europhys. Lett. 101 (2013) 20004]. We show that the same condition can give rise to unbounded Killing energy of debris at infinity, i.e. super-Penrose process. Proximity of the point of collision to the black hole horizon is not required.

  16. Eyewitness Identification Reform: Data, Theory, and Due Process.

    Science.gov (United States)

    Clark, Steven E

    2012-05-01

    Some commentators view my analyses (Clark, 2012, this issue) as an important step forward in assessing the costs and benefits of eyewitness identification reform. Others suggest that the trade-off between correct identifications lost and false identifications avoided is well-known; that the expected utility model is misspecified; and that the loss of correct identifications due to the use of reformed eyewitness identification procedures is irrelevant to policy decisions, as those correct identifications are the illegitimate product of suggestion and lucky guesses. Contrary to these criticisms, the loss of correct identifications has not been adequately considered in theoretical or policy matters, criticisms regarding the various utilities do not substantively change the nature of the trade-off, and the dismissal of lost correct identifications is based not on data but on an outdated theory of recognition memory. © The Author(s) 2012.

  17. Guinea-pig interpubic joint (symphysis pubica relaxation at parturition: Underlying cellular processes that resemble an inflammatory response

    Directory of Open Access Journals (Sweden)

    Muñoz-de-Toro Mónica

    2003-11-01

    Full Text Available Abstract Background At term, cervical ripening in coordination with uterine contractions becomes a prerequisite for a normal vaginal delivery. Currently, cervical ripening is considered to occur independently from uterine contractions. Many evidences suggest that cervical ripening resembles an inflammatory process. Comparatively little attention has been paid to the increased flexibility of the pelvic symphysis that occurs in many species to enable safe delivery. The aim of this study was to investigate whether the guinea-pig interpubic joint relaxation process observed during late pregnancy and parturition resembles an inflammatory process. Methods Samples of pubic symphysis were taken from pregnant guinea-pigs sacrificed along gestation, parturition and postpartum. Serial sections of paraffin-embedded tissues were used to measure the interpubic distance on digitalized images, stained with Giemsa to quantify leukocyte infiltration and to describe the vascular area changes, or studied by the picrosirius-polarization method to evaluate collagen remodeling. P4 and E2 serum levels were measured by a sequential immunometric assay. Results Data showed that the pubic relaxation is associated with an increase in collagen remodeling. In addition, a positive correlation between E2 serum levels and the increase in the interpubic distance was found. On the other hand, a leukocyte infiltration in the interpubic tissue around parturition was described, with the presence of almost all inflammatory cells types. At the same time, histological images show an increase in vascular area (angiogenesis. Eosinophils reached their highest level immediately before parturition; whereas for the neutrophilic and mononuclear infiltration higher values were recorded one day after parturition. Correlation analysis showed that eosinophils and mononuclear cells were positively correlated with E2 levels, but only eosinophilic infiltration was associated with collagen remodeling

  18. Selective modulation of nociceptive processing due to noise distraction.

    Science.gov (United States)

    Boyle, Yvonne; El-Deredy, Wael; Martínez Montes, Eduardo; Bentley, Deborah E; Jones, Anthony K P

    2008-09-15

    This study investigates the effects of noise distraction on the different components and sources of laser-evoked potentials (LEPs) whilst attending to either the spatial component (localisation performance task) or the affective component (unpleasantness rating task) of pain. LEPs elicited by CO2 laser stimulation of the right forearm were recorded from 64 electrodes in 18 consenting healthy volunteers. Subjects reported either pain location or unpleasantness, in the presence and absence of distraction by continuous 85 dBa white noise. Distributed sources of the LEP peaks were identified using Low Resolution Electromagnetic Tomography (LORETA). Pain unpleasantness ratings and P2 (430 ms) peak amplitude were significantly reduced by distraction during the unpleasantness task, whereas the localisation ability and the corresponding N1/N2 (310 ms) peak amplitude remained unchanged. Noise distraction (at 310 ms) reduced activation in the anterior cingulate cortex (ACC) and precuneus during attention to localisation and unpleasantness, respectively. This suggests a complimentary role for these two areas in the control of attention to pain. In contrast, activation of the occipital pole and SII were enhanced by noise during the localisation and unpleasantness task, respectively, suggesting that the presence of noise was associated with increased spatial attentional load. This study has shown selective modulation of affective pain processing by noise distraction, indicated by a reduction in the unpleasantness ratings and P2 peak amplitude and associated activity within the medial pain system. These results show that processing of the affective component of pain can be differentially modulated by top-down processes, providing a potential mechanism for therapeutic intervention.

  19. Process Measurement Deviation Analysis for Flow Rate due to Miscalibration

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eunsuk; Kim, Byung Rae; Jeong, Seog Hwan; Choi, Ji Hye; Shin, Yong Chul; Yun, Jae Hee [KEPCO Engineering and Construction Co., Deajeon (Korea, Republic of)

    2016-10-15

    An analysis was initiated to identify the root cause, and the exemption of high static line pressure correction to differential pressure (DP) transmitters was one of the major deviation factors. Also the miscalibrated DP transmitter range was identified as another major deviation factor. This paper presents considerations to be incorporated in the process flow measurement instrumentation calibration and the analysis results identified that the DP flow transmitter electrical output decreased by 3%. Thereafter, flow rate indication decreased by 1.9% resulting from the high static line pressure correction exemption and measurement range miscalibration. After re-calibration, the flow rate indication increased by 1.9%, which is consistent with the analysis result. This paper presents the brief calibration procedures for Rosemount DP flow transmitter, and analyzes possible three cases of measurement deviation including error and cause. Generally, the DP transmitter is required to be calibrated with precise process input range according to the calibration procedure provided for specific DP transmitter. Especially, in case of the DP transmitter installed in high static line pressure, it is important to correct the high static line pressure effect to avoid the inherent systematic error for Rosemount DP transmitter. Otherwise, failure to notice the correction may lead to indicating deviation from actual value.

  20. The influence of secondary processing on the structural relaxation dynamics of fluticasone propionate.

    Science.gov (United States)

    Depasquale, Roberto; Lee, Sau L; Saluja, Bhawana; Shur, Jagdeep; Price, Robert

    2015-06-01

    This study investigated the structural relaxation of micronized fluticasone propionate (FP) under different lagering conditions and its influence on aerodynamic particle size distribution (APSD) of binary and tertiary carrier-based dry powder inhaler (DPI) formulations. Micronized FP was lagered under low humidity (LH 25 C, 33% RH [relative humidity]), high humidity (HH 25°C, 75% RH) for 30, 60, and 90 days, respectively, and high temperature (HT 60°C, 44% RH) for 14 days. Physicochemical, surface interfacial properties via cohesive-adhesive balance (CAB) measurements and amorphous disorder levels of the FP samples were characterized. Particle size, surface area, and rugosity suggested minimal morphological changes of the lagered FP samples, with the exception of the 90-day HH (HH90) sample. HH90 FP samples appeared to undergo surface reconstruction with a reduction in surface rugosity. LH and HH lagering reduced the levels of amorphous content over 90-day exposure, which influenced the CAB measurements with lactose monohydrate and salmeterol xinafoate (SX). CAB analysis suggested that LH and HH lagering led to different interfacial interactions with lactose monohydrate but an increasing adhesive affinity with SX. HT lagering led to no detectable levels of the amorphous disorder, resulting in an increase in the adhesive interaction with lactose monohydrate. APSD analysis suggested that the fine particle mass of FP and SX was affected by the lagering of the FP. In conclusion, environmental conditions during the lagering of FP may have a profound effect on physicochemical and interfacial properties as well as product performance of binary and tertiary carrier-based DPI formulations.

  1. Experimental evidence for simultaneous relaxation processes in super spin glass γ-Fe{sub 2}O{sub 3} nanoparticle system

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, V.; Perovic, M., E-mail: mara.perovic@vinca.rs; Kusigerski, V.; Boskovic, M.; Mrakovic, A.; Blanusa, J.; Spasojevic, V. [University of Belgrade, Condensed Matter Physics Laboratory, Institute of Nuclear Sciences Vinca (Serbia)

    2015-03-15

    Spherical γ-Fe{sub 2}O{sub 3} nanoparticles with the narrow size distribution of (5 ± 1) nm were synthesized by the method of thermal decomposition from iron acetyl acetonate precursor. The existence of super spin-glass state at low temperatures and in low applied magnetic fields was confirmed by DC magnetization measurements on a SQUID magnetometer. The comprehensive investigation of magnetic relaxation dynamics in low-temperature region was conducted through the measurements of single-stop and multiple stop ZFC memory effects, ZFC magnetization relaxation, and AC susceptibility measurements. The experimental findings revealed the peculiar change of magnetic relaxation dynamics at T ≈ 10 K, which arose as a consequence of simultaneous existence of different relaxation processes in Fe{sub 2}O{sub 3} nanoparticle system. Complementarity of the applied measurements was utilized in order to single out distinct relaxation processes as well as to elucidate complex relaxation mechanisms in the investigated interacting nanoparticle system.

  2. Influence of Nanodisperse Metal Fillers on the Viscoelastic Properties and Processes of Mechanical Relaxation of Polymer Systems

    Science.gov (United States)

    Kolupav, B. B.; Kolupaev, B. S.; Levchuk, V. V.; Maksimtsev, Yu. R.; Sidletskii, V. A.

    2017-05-01

    The results of research into the viscoelastic properties and processes of mechanical relaxation of polyvinylchloride (PVC) containing Cu nanoparticles obtained by means of electroerosion crushing and electrohydraulic destruction of agglomerates of disperse Cu in the presence of an ultrasonic field are presented. It is shown that, in the case of longitudinal shear deformation at a frequency of 0.4 × 106 s-1 over a wide range of temperatures and content of ingredients, viscoelastic phenomena depending on structural changes in the PVC system occur. An analysis of quantitative results of the elastic and viscoelastic deformation of a body is carried out taking into account the energy and entropy components of interaction of the polymer and filler at their interface.

  3. Effect of radiation and non-Maxwellian electron distribution on relaxation processes in an atmospheric cesium seeded argon plasma

    International Nuclear Information System (INIS)

    Borghi, C.A.; Veefkind, A.; Wetzer, J.M.

    1982-03-01

    A model, describing the time dependent behaviour of a noble gas MHD generator plasma, has been set up. With this model it is possible to calculate the relaxation for ionization or recombination as a response to a stepwise temperature development, once the initial and final conditions are given. In model radiative transitions and a deviation from Maxwellian electron distribution are included. Radiation causes an enhancement of both the ionization relaxation time and the recombination relaxation time. A non-Maxwellian electron distribution results in an increase of the relaxation time for an ionizing plasma because of an underpopulation of the high energy electrons. A decrease of the relaxation time for a recombining plasma is caused by an overpopulation of high energy electrons. The relaxation time is strongly dependent on the seed ratio and the temperature step. (Auth.)

  4. Elevated intrabolus pressure identifies obstructive processes when integrated relaxation pressure is normal on esophageal high-resolution manometry.

    Science.gov (United States)

    Quader, Farhan; Reddy, Chanakyaram; Patel, Amit; Gyawali, C Prakash

    2017-07-01

    Elevated integrated relaxation pressure (IRP) on esophageal high-resolution manometry (HRM) identifies obstructive processes at the esophagogastric junction (EGJ). Our aim was to determine whether intrabolus pressure (IBP) can identify structural EGJ processes when IRP is normal. In this observational cohort study, adult patients with dysphagia and undergoing HRM were evaluated for endoscopic evidence of structural EGJ processes (strictures, rings, hiatus hernia) in the setting of normal IRP. HRM metrics [IRP, distal contractile integral (DCI), distal latency (DL), IBP, and EGJ contractile integral (EGJ-CI)] were compared among 74 patients with structural EGJ findings (62.8 ± 1.6 yr, 67.6% women), 27 patients with normal EGD (52.9 ± 3.2 yr, 70.3% women), and 21 healthy controls (27.6 ± 0.6 yr, 52.4% women). Findings were validated in 85 consecutive symptomatic patients to address clinical utility. In the primary cohort, mean IBP (18.4 ± 0.9 mmHg) was higher with structural EGJ findings compared with dysphagia with normal EGD (13.5 ± 1.1 mmHg, P = 0.002) and healthy controls (10.9 ± 0.9 mmHg, P 0.05 for each comparison). During multiple rapid swallows, IBP remained higher in the structural findings group compared with controls ( P = 0.02). Similar analysis of the prospective validation cohort confirmed IBP elevation in structural EGJ processes, but correlation with dysphagia could not be demonstrated. We conclude that elevated IBP predicts the presence of structural EGJ processes even when IRP is normal, but correlation with dysphagia is suboptimal. NEW & NOTEWORTHY Integrated relaxation pressure (IRP) above the upper limit of normal defines esophageal outflow obstruction using high-resolution manometry. In patients with normal IRP, elevated intrabolus pressure (IBP) can be a surrogate marker for a structural restrictive or obstructive process at the esophagogastric junction (EGJ). This has the potential to augment the clinical value of

  5. Procedural Due Process and Fairness in Student Discipline. A Legal Memorandum.

    Science.gov (United States)

    Johnson, T. Page

    When the Supreme Court decided that the Constitution requires public school principals to follow procedural due process in suspension and expulsion cases, the Justices recognized a link between procedural due process and the fairness of effective discipline. This report reviews the constitutional due process required when public school officials…

  6. Process of advective diffusive enrichment using differential gradients and the effects of variations in relaxation times

    International Nuclear Information System (INIS)

    Suarez Antola R.; Bernasconi, G.; Bertolotti, Angel

    1995-01-01

    A multicomponent solution is considered in advective diffusion chambers between two half-permeable barriers. A mathematical model is developed to calculate the concentration fields in the chamber. A new enrichment process is proposed and assessed using a digital simulation of space-time dynamics, based on the analytical solution of the model

  7. Relaxation and excitation electronic processes in dielectrics irradiated by ultrafast IR and VUV pulses; Processus electroniques d'excitation et de relaxation dans les solides dielectriques excites par des impulsions IR et XUV ultracourtes

    Energy Technology Data Exchange (ETDEWEB)

    Gaudin, J

    2005-11-15

    We studied excitation and relaxation of electrons involved during interaction of visible and VUV femtosecond pulses with dielectrics. The generated population of hot electrons, having energy of few eV to few tens of eV above the bottom of the conduction band, is responsible of phenomena ranging to defect creation to optical breakdown. Owing to two techniques: photoemission and transient photoconductivity we improve the understanding of the The first photoemission experiments deal with dielectrics irradiated by 30 fs IR pulses. The photoemission spectra measured show a large population of electrons which energy rise up to 40 eV. We interpret this result in terms of a new absorption process: direct multi-photons inter-branch transitions. The 2. type of photoemission experiments are time resolved 'pump/probe' investigation. We study the relaxation of electrons excited by a VUV pulses. We used the high order harmonics (HOH) as light sources. We found surprisingly long decay time in the range of ps timescale. Last type of experiments is photoconductivity studies of diamond samples. Using HOH as light source we measure the displacement current induced by excited electrons in the conduction band. Those electrons relax mainly by impact ionisation creating secondary electrons. Hence by probing the number of electrons we were able to measure the efficiency of these relaxation processes. We observe a diminution of this efficiency when the energy of exciting photons is above 20 eV. Owing to Monte-Carlo simulation we interpret this result in terms of band structure effect. (author)

  8. Postseismic relaxation process and lithospheric rheology inferred from eight years of postseismic deformation after the 2008 Mw7.9 Wenchuan earthquake

    Science.gov (United States)

    Zhao, B.; Burgmann, R.; Rui, X.; Wang, D.; Yu, J.; He, K.

    2017-12-01

    Current inferences of postseismic deformation mechanisms and lithospheric rheology in the eastern Tibetan Plateau strongly depend on spatial and temporal observations of postseismic transients following the 2008 Mw=7.9 Wenchuan earthquake. We processed regional continuously operating and survey-mode GPS data from the Crustal Movement Observation Network of China and Sichuan Continuous Operation Reference System. These data cover a broad region and time intervals of up to eight years. The determined amplitude of postseismic displacements show clear contrast between the Sichuan Basin and eastern Tibet. In addition to significant amounts of deformation in the region between the Longmen Shan and Longriba fault, reliable deformation transients are also visible in the far field, such as regions to the west of the Longriba fault and along the left-lateral Xianshuihe fault. In contrast, no more than 10 mm of postseismic transients are observed in the Sichuan Basin. Guided by previous studies, we conducted multiple-mechanism models of afterslip and viscoelastic relaxation. We first explored a series of forward viscoelastic relaxation models using a heterogeneous rheological earth structure, and then inverted corresponding afterslip distributions on the shallowly dipping detachment to explain the remaining residuals. Our preliminary results indicate the viscoelastic relaxation in the lower crust and upper mantle dominantly contributed to the mid- and far-field observations, whereas afterslip below the coseismic asperities and on small patches near the surface can explain the near-field measurements. Time-dependent slip inversions illustrate that afterslip decays more rapidly on the shallow portions of the fault interface than on the shallowly dipping detachment. Relatively long-lived right-lateral afterslip is revealed in the north segment of the Beichuan fault, suggesting variations of frictional properties along strike of the fault zone. Our results also support previous

  9. Uncovering molecular relaxation processes with nonlinear spectroscopies in the deep UV

    International Nuclear Information System (INIS)

    West, Brantley A.; Molesky, Brian P.; Giokas, Paul G.; Moran, Andrew M.

    2013-01-01

    Highlights: • We discuss the outlook for multidimensional spectroscopies in the deep UV. • Photophysics are examined in small DNA components at cryogenic temperatures. • Wavepacket motions are detected in ring-opening systems with 2DUV spectroscopy. • Measurements of electronic wavepacket motions in molecules are proposed. - Abstract: Nonlinear laser spectroscopies in the deep UV spectral range are motivated by studies of biological systems and elementary processes in small molecules. This perspective article discusses recent technical advances in this area with a particular emphasis on diffractive optic based approaches to four-wave mixing spectroscopies. Applications to two classes of systems illustrate present experimental capabilities. First, experiments on DNA components at cryogenic temperatures are used to uncover features of excited state potential energy surfaces and vibrational cooling mechanisms. Second, sub-200 fs internal conversion processes and coherent wavepacket motions are investigated in cyclohexadiene and α-terpinene. Finally, we propose new experimental directions that combine methods for producing few-cycle UV laser pulses in noble gases with incoherent detection methods (e.g., photoionization) in experiments with time resolution near a singlefemtosecond. These measurements are motivated by knowledge of extremely fast non-adiabatic dynamics and the resolution of electronic wavepacket motions in molecules

  10. Influence of relaxation processes in polymers on energy transfer by triplet levels

    International Nuclear Information System (INIS)

    Ibraev, N.Kh.; Zhunusbekov, A.M.

    1996-01-01

    Temperature influence on triplet-triplet (T-T) energy transfer between molecules of eosin and 3,4-benzopyrene is studied. Polyvenylbuteryl films have been used in capacity of polymer matrix. Calculation has being carried out on spectral-kinetic unit. It is revealed, that 3,4-benzopyrene triplets have been formed in polymer matrix after end of T-T energy transfer. These triplets join in a reaction of mixed triplet-triplet annihilation with non-blow out triplets of eosin and its sensitize slowed fluorescence (SF) of donor. This explains non-exponent character of eosin's dumping kinetics. Non-linear dependence of SF output ration to eosin phosphorescence output under presence of 3,4-benzopyrene molecules in film indicates on process of mixed annihilation. Fractal character of SF donor and acceptor has been evidenced about microscopical distribution of phosphor in polymer. 13 refs., 5 figs

  11. Effects of electric paravertebral muscle relaxation processes in the athletes heart

    Directory of Open Access Journals (Sweden)

    D. V. Syshko

    2013-02-01

    Full Text Available Influence of paravertebrals miorelaxation on electric processes in a heart at sportsmen is studied. Paravertebrals miorelaxation was the complex of exercises in a water environment directed on the decline of tone of paravertebral muscles. Before and after it was used of paravertebrals miorelaxation registered the indexes of electrocardiography at the sportsmen engaged in the Greek-Roman fight (n=22 by football (n=24 and heavy athletics (n=25. It is got, that at the sportsmen of engaged in the Greek -Roman fight after paravertebrals miorelaxation QRS and QT were it was increased, and R-R and PQ went down. At the sportsmen of engaged in heavy athletics HR and PQ went down after paravertebrals miorelaxation, R-R, QRS and QT were it was increased. At the sportsmen of getting busy by football the PQ interval shortened, and QRS and QT has multiplied. Findings testify to the presence of different mechanisms of adaptation of the conducting system of heart in the conditions of influencing of paravertebrals miorelaxation. These distinctions are fated by two basic factors: by the functional being of the cardio-vessels system on the whole and functional being of sine knot and conducting system of heart in particular.

  12. Radiation effects on oxide glasses: Importance of energy deposition and relaxation processes

    International Nuclear Information System (INIS)

    Mir, Anamul-Haq

    2015-01-01

    Nuclear waste glass matrices during their disposal will be subjected to self-irradiation by beta and alpha decays. Beta emitting radionuclides due to their short half life time will be the dominant radiation source only during first few hundred years of the disposal, whereas the alpha decays constitute a long term radiation source. Due to intense beta decay and associated gamma rays, the glass matrices can attain temperatures up to 300 C during state 1. The temperature during stage 2 will mainly be defined by the repository conditions. The present work focused on studying the response of various glasses (borosilicate glasses of nuclear waste interest and amorphous silica) to electron irradiation (to understand the response of the pristine glasses to beta decays), single ion beam irradiations with light and heavy ions over a wide stopping power and fluence range (to study the response of the pristine glasses as a function of the electronic and nuclear energy loss so as to establish the necessary conditions for simulating the alpha and recoil nuclei damage), sequential electron-ion irradiations (to understand the impact of the intense beta decay damage during stage 1 on subsequent alpha decay during stage 2, and double ion beam sequential and simultaneous irradiations (to understand the interaction of the alpha particles with recoil nuclei pre-damaged glass and vice versa). The pristine and irradiated samples were characterized using Raman spectroscopy, NMR spectroscopy, micro and nano indentation, AFM, interferometry and ToF-SIMS. Apart from the experimental work, Inelastic Thermal Spike Model (iTSM) for ion track formation was extended to borosilicate glasses to study the possibility of ion track formation in nuclear waste glass matrices. The model was used to study the impact of matrix temperature and stored energy on the ion track threshold, which is otherwise difficult to study experimentally. During electron irradiation, the response of the glasses was found to

  13. Enhanced atomic mobility due to low dose neutron irradiation as measured in a 30Ag at % Zn alloy by Zener relaxation methods

    International Nuclear Information System (INIS)

    Halbwachs, M.; Hillairet, J.; Gonzalez, H.; Cost, J.

    1975-01-01

    Mean atomic jump rates were measured during and after short-time neutron irradiations of a fcc Ag-30 at. percent Zn alloy by monitoring the rate of the Zener relaxation. Measurements made at 40 0 C immediately after rapid suppression of the flux showed significant enhancement of the atomic mobility for a flux of approximately 10 11 fast n/cm 2 .sec and an irradiation time of only 30 sec. The subsequent decrease of the atomic mobility to the thermal equilibrium value was studied and found to follow simple exponential decay. The results are discussed in terms of the nature and concentration of mobile defects created by cascades, the mechanism for defect annihilation and the concentration of sinks

  14. Due Process in the Realm of Higher Education: Considerations for Dealing with Students Rights

    Science.gov (United States)

    Fishner, Jason T.

    2006-01-01

    Court decisions have laid out expectations of what due process procedures need to be followed in student disciplinary cases and academic dismissal cases due to poor academic performance. This paper will give show where due process comes from and how it found its way into higher education. It will show that there are differences in the ways public…

  15. In vivo measurements of the T1 relaxation processes in the bone marrow in patients with myelodysplastic syndrome

    International Nuclear Information System (INIS)

    Jensen, K.E.; Nielsen, H.; Thomsen, C.; Soerensen, P.G.; Karle, H.; Christoffersen, P.; Henriksen, O.; Hvidovre Hospital, Copenhagen; Hvidovre Hospital, Copenhagen

    1989-01-01

    Nine patients with myelodysplastic syndrome (MDS) were examined with magnetic resonance imaging and in vivo T1 relaxation time measurements of the vertebral bone marrow in a 1.5 tesla whole body scanner. Two patients underwent transformation to acute myeloid leukemia and were evaluated at follow-up examinations. At the time of diagnosis the T1 relaxation times of the vertebral bone marrow were significantly prolonged compared with normal values. The T1 relaxation times of the vertebral bone marrow in patients with MDS showed significantly lower values compared with patients with acute leukemia and did not differ from patients with polycythemia vera. (orig.)

  16. Statistical mechanical approach to secondary processes and structural relaxation in glasses and glass formers: a leading model to describe the onset of Johari-Goldstein processes and their relationship with fully cooperative processes.

    Science.gov (United States)

    Crisanti, A; Leuzzi, L; Paoluzzi, M

    2011-09-01

    The interrelation of dynamic processes active on separated time-scales in glasses and viscous liquids is investigated using a model displaying two time-scale bifurcations both between fast and secondary relaxation and between secondary and structural relaxation. The study of the dynamics allows for predictions on the system relaxation above the temperature of dynamic arrest in the mean-field approximation, that are compared with the outcomes of the equations of motion directly derived within the Mode Coupling Theory (MCT) for under-cooled viscous liquids. By varying the external thermodynamic parameters, a wide range of phenomenology can be represented, from a very clear separation of structural and secondary peak in the susceptibility loss to excess wing structures.

  17. Changes in T1 relaxation processes in the bone marrow following treatment in children with acute lymphoblastic leukemia

    International Nuclear Information System (INIS)

    Jensen, K.E.; Thomsen, C.; Henriksen, O.; Hertz, H.; Johansen, H.K.; Yssing, M.

    1990-01-01

    Magnetic resonance imaging (MRI) and T 1 relaxation time measurements of the vertebral bone marrow were performed in 11 children with acute lymphoblastic leukemia (ALL) at diagnosis. Nine of the children were re-examined after chemotherapeutic treatment. The results were compared with histological data from bone marrow biopsies obtained in close association to the MR examinations. Ten age matched children were examined as a control group. A 1.5 Tesla whole body scanner was used for the measurements. The pretreatment T 1 relaxation times of the bone marrow were significantly prolonged, compared to the age matched controls. After chemotherapy the T 1 relaxation times of the children with ALL decreased significantly towards or into the normal range. A significant correlation was found between the T 1 relaxation time and the content of malignant blast cells in the bone marrow. (orig.)

  18. Relationship between the catalytic activity of Pt/alumina and the relaxation process of the photoexcited electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Junji, E-mail: j-itou@mail.nissan.co.jp [Advanced Materials Laboratory, Nissan Research Center, NISSAN MOTOR CO., LTD., 1 Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523 (Japan); Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Hanaki, Yasunari [Advanced Materials Laboratory, Nissan Research Center, NISSAN MOTOR CO., LTD., 1 Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523 (Japan); Shen, Qing [Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Department of Engineering Science, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Toyoda, Taro [Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Department of Engineering Science, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We determined the decay time of photoexcited electrons of Pt/Al{sub 2}O{sub 3}. Black-Right-Pointing-Pointer Faster decay of excited electrons in Pt/Al{sub 2}O{sub 3} leads to its faster oxidation rate. Black-Right-Pointing-Pointer Decreasing excited electron lifetime in Pt/Al{sub 2}O{sub 3} may decrease Pt consumption in catalytic convertors. - Abstract: In order to decrease the consumption of precious metals used in the catalytic converters used in automobiles, we studied the relationship between the catalytic activity of Pt/alumina (Pt/Al{sub 2}O{sub 3}) and the relaxation process of photoexcited electrons. Firstly, we studied the relationship between the size of the Pt particles in Pt/Al{sub 2}O{sub 3} and catalytic performance. Secondly, the relationship between the size of the Pt particles in Pt/Al{sub 2}O{sub 3} and the decay time of the excited electrons was studied using an improved transient grating (TG) technique. The results showed that faster decay of the excited electrons leads to greater oxidation rates. The decay time obtained with the improved TG technique gives an indication of the time that the exited electrons take to return to the ground state. According to studies utilizing FT-IR, one of the processes necessary for quickly generating CO{sub 2} with Pt is that the electron in the Pt-O bond moves to the Pt side and that the Pt{sup +} becomes Pt metal. Thus, the decay time obtained with the improved TG technique corresponds to the process whereby Pt{sup +} returns to Pt metal. Thus, we found that the consumption of precious metals can be reduced by increasing the speed of the decay of the excited electrons.

  19. Relationship between the catalytic activity of Pt/alumina and the relaxation process of the photoexcited electrons

    International Nuclear Information System (INIS)

    Ito, Junji; Hanaki, Yasunari; Shen, Qing; Toyoda, Taro

    2012-01-01

    Highlights: ► We determined the decay time of photoexcited electrons of Pt/Al 2 O 3 . ► Faster decay of excited electrons in Pt/Al 2 O 3 leads to its faster oxidation rate. ► Decreasing excited electron lifetime in Pt/Al 2 O 3 may decrease Pt consumption in catalytic convertors. - Abstract: In order to decrease the consumption of precious metals used in the catalytic converters used in automobiles, we studied the relationship between the catalytic activity of Pt/alumina (Pt/Al 2 O 3 ) and the relaxation process of photoexcited electrons. Firstly, we studied the relationship between the size of the Pt particles in Pt/Al 2 O 3 and catalytic performance. Secondly, the relationship between the size of the Pt particles in Pt/Al 2 O 3 and the decay time of the excited electrons was studied using an improved transient grating (TG) technique. The results showed that faster decay of the excited electrons leads to greater oxidation rates. The decay time obtained with the improved TG technique gives an indication of the time that the exited electrons take to return to the ground state. According to studies utilizing FT-IR, one of the processes necessary for quickly generating CO 2 with Pt is that the electron in the Pt-O bond moves to the Pt side and that the Pt + becomes Pt metal. Thus, the decay time obtained with the improved TG technique corresponds to the process whereby Pt + returns to Pt metal. Thus, we found that the consumption of precious metals can be reduced by increasing the speed of the decay of the excited electrons.

  20. The effects of progressive muscular relaxation as a nursing procedure used for those who suffer from stress due to multiple sclerosis.

    Science.gov (United States)

    Novais, Paolla Gabrielle Nascimento; Batista, Karla de Melo; Grazziano, Eliane da Silva; Amorim, Maria Helena Costa

    2016-09-01

    to evaluate the effect of progressive muscle relaxation as a nursing procedure on the levels of stress for sufferers of multiple sclerosis. random clinical trials conducted at the Neurology outpatients unit at a University Hospital. The sample consisted of 40 patients who were being monitored as outpatients (20 in a control group and 20 in an experimental group). The Progressive Muscle Relaxation technique was used. The control variables were collected through interviews that were recorded on forms and on the Perceived Stress Scale that we used. Five meetings were held every fortnight covering a period of eight weeks. The experimental group was advised to carry out daily progressive muscle relaxation activities. After eight weeks of these activities, they were evaluated again to measure their levels of stress. In order to analyze the data used, the software package Statistics for Social Sciences version 19.0 was used. the application of the t test showed a significant reduction in the Perceived Stress Scale scores in the experimental group (pencontros quinzenais em um período de oito semanas. O grupo experimental foi orientado a realizar diariamente o Relaxamento Muscular Progressivo. Após oito semanas de intervenção avaliou-se novamente os níveis de estresse. Para análise dos dados foi utilizado o pacote Estatístico para Ciências Sociais-versão 19.0. a aplicação do Teste t demonstrou uma diminuição significante dos escores da Escala de Stress Percebido no grupo experimental (p<0,001), evidenciando diminuição nos níveis de estresse após a prática do relaxamento. a intervenção Relaxamento Muscular Progressivo contribui para redução dos níveis de estresse em pessoas com Esclerose Múltipla, podendo ser incluída como prática na assistência de enfermagem prestada a esses pacientes. NCT 02673827. evaluar el efecto del Relajamiento Muscular Progresivo, como intervención de Enfermería en los niveles de estrés en personas con Esclerosis

  1. Mechanism of nuclear cross-relaxation in magnetically ordered media

    Energy Technology Data Exchange (ETDEWEB)

    Buishvili, L L; Volzhan, E B; Giorgadze, N P [AN Gruzinskoj SSR, Tbilisi. Inst. Fiziki

    1975-09-01

    A mechanism of two-step nuclear relaxation in magnetic ordered dielectrics is proposed. The case is considered where the energy conservation in the cross relaxation (CR) process is ensured by the lattice itself without spin-spin interactions. Expressions have been obtained describing the temperature dependence of the CR rate. For a nonuniform broadened NMR line it has been shown that the spin-lattice relaxation time for a spin packet taken out from the equilibrium may be determined by the CR time owing to the mechanism suggested. When the quantization axes for electron and nuclear spins coincide, the spin-lattice relaxation is due to the three-magnon mechanism. The cross-relaxation stage has been shown to play a significant role in the range of low temperatures (T<10 deg K) and to become negligible with a temperature increase.

  2. Relaxation processes and glass transition of confined polymer melts: A molecular dynamics simulation of 1,4-polybutadiene between graphite walls.

    Science.gov (United States)

    Solar, M; Binder, K; Paul, W

    2017-05-28

    Molecular dynamics simulations of a chemically realistic model for 1,4-polybutadiene in a thin film geometry confined by two graphite walls are presented. Previous work on melts in the bulk has shown that the model faithfully reproduces static and dynamic properties of the real material over a wide temperature range. The present work studies how these properties change due to nano-confinement. The focus is on orientational correlations observable in nuclear magnetic resonance experiments and on the local intermediate incoherent neutron scattering function, F s (q z , z, t), for distances z from the graphite walls in the range of a few nanometers. Temperatures from about 2T g down to about 1.15T g , where T g is the glass transition temperature in the bulk, are studied. It is shown that weakly attractive forces between the wall atoms and the monomers suffice to effectively bind a polymer coil that is near the wall. For a wide regime of temperatures, the Arrhenius-like adsorption/desorption kinetics of the monomers is the slowest process, while very close to T g the Vogel-Fulcher-Tammann-like α-relaxation takes over. The α-process is modified only for z≤1.2 nm due to the density changes near the walls, less than expected from studies of coarse-grained (bead-spring-type) models. The weakness of the surface effects on the glass transition in this case is attributed to the interplay of density changes near the wall with the torsional potential. A brief discussion of pertinent experiments is given.

  3. Electron spin relaxation governed by Raman processes both for Cu2+ ions and carbonate radicals in KHCO3 crystals: EPR and electron spin echo studies

    Science.gov (United States)

    Hoffmann, Stanislaw K.; Goslar, Janina; Lijewski, Stefan

    2012-08-01

    EPR studies of Cu2+ and two free radicals formed by γ-radiation were performed for KHCO3 single crystal at room temperature. From the rotational EPR results we concluded that Cu2+ is chelated by two carbonate molecules in a square planar configuration with spin-Hamiltonian parameters g|| = 2.2349 and A|| = 18.2 mT. Free radicals were identified as neutral HOCOrad with unpaired electron localized on the carbon atom and a radical anion CO3·- with unpaired electron localized on two oxygen atoms. The hyperfine splitting of the EPR lines by an interaction with a single hydrogen atom of HOCOrad was observed with isotropic coupling constants ao = 0.31 mT. Two differently oriented radical sites were identified in the crystal unit cell. Electron spin-lattice relaxation measured by electron spin echo methods shows that both Cu2+ and free radicals relax via two-phonon Raman processes with almost the same relaxation rate. The temperature dependence of the relaxation rate 1/T1 is well described with the effective Debye temperature ΘD = 175 K obtained from a fit to the Debye-type phonon spectrum. We calculated a more realistic Debye temperature value from available elastic constant values of the crystal as ΘD = 246 K. This ΘD-value and the Debye phonon spectrum approximation give a much worse fit to the experimental results. Possible contributions from a local mode or an optical mode are considered and it is suggested that the real phonon spectrum should be used for the relaxation data interpretation. It is unusual that free radicals in KHCO3 relax similarly to the well localized Cu2+ ions, which suggests a small destruction of the host crystal lattice by the ionizing irradiation allowing well coupling between radical and lattice dynamics.

  4. Slowing hot-carrier relaxation in graphene using a magnetic field

    Science.gov (United States)

    Plochocka, P.; Kossacki, P.; Golnik, A.; Kazimierczuk, T.; Berger, C.; de Heer, W. A.; Potemski, M.

    2009-12-01

    A degenerate pump-probe technique is used to investigate the nonequilibrium carrier dynamics in multilayer graphene. Two distinctly different dynamics of the carrier relaxation are observed. A fast relaxation (˜50fs) of the carriers after the initial effect of phase-space filling followed by a slower relaxation (˜4ps) due to thermalization. Both relaxation processes are less efficient when a magnetic field is applied at low temperatures which is attributed to the suppression of the electron-electron Auger scattering due to the nonequidistant Landau-level spacing of the Dirac fermions in graphene.

  5. The Analytical Pragmatic Structure of Procedural Due Process: A Framework for Inquiry in Administrative Decision Making.

    Science.gov (United States)

    Fisher, James E.; Sealey, Ronald W.

    The study describes the analytical pragmatic structure of concepts and applies this structure to the legal concept of procedural due process. This structure consists of form, purpose, content, and function. The study conclusions indicate that the structure of the concept of procedural due process, or any legal concept, is not the same as the…

  6. 25 CFR 42.6 - When does due process require a formal disciplinary hearing?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When does due process require a formal disciplinary... RIGHTS § 42.6 When does due process require a formal disciplinary hearing? Unless local school policies and procedures provide for less, a formal disciplinary hearing is required before a suspension in...

  7. Single-machine common/slack due window assignment problems with linear decreasing processing times

    Science.gov (United States)

    Zhang, Xingong; Lin, Win-Chin; Wu, Wen-Hsiang; Wu, Chin-Chia

    2017-08-01

    This paper studies linear non-increasing processing times and the common/slack due window assignment problems on a single machine, where the actual processing time of a job is a linear non-increasing function of its starting time. The aim is to minimize the sum of the earliness cost, tardiness cost, due window location and due window size. Some optimality results are discussed for the common/slack due window assignment problems and two O(n log n) time algorithms are presented to solve the two problems. Finally, two examples are provided to illustrate the correctness of the corresponding algorithms.

  8. Standard Setting as Psychometric Due Process: Going a Little Further Down an Uncertain Road.

    Science.gov (United States)

    Cizek, Gregory J.

    The concept of due process provides an analogy for the process of standard setting that emphasizes many of the procedural and substantive elements of the process over technical and statistical concerns. Surely such concerns can and should continue to be addressed. However, a sound rationale for standard setting does not rest on this foundation.…

  9. The due-diligence process of purchasing or buying into a dental practice.

    Science.gov (United States)

    Conner, Vincent L

    2003-01-01

    A due-diligence or evaluation process is necessary when assessing a practice purchase opportunity. The standards for assessing the investment remain the same whether the buyer is purchasing a practice outright or buying a co-ownership interest.

  10. Ionization yield and absorption spectra reveal superexcited Rydberg state relaxation processes in H{sub 2}O and D{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Fillion, J-H [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Dulieu, F [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Baouche, S [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Lemaire, J-L [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Jochims, H W [Institut fuer Physikalische und Theoretische Chemie der Freien Universitaet Berlin, Takustrasse 3, D-14195 Berlin 33 (Germany); Leach, S [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France)

    2003-07-14

    The absorption cross section and the ionization quantum yield of H{sub 2}O have been measured using a synchrotron radiation source between 9 and 22 eV. Comparison between the two curves highlights competition between relaxation processes for Rydberg states converging to the first A-tilde {sup 2}A{sub 1} and to the second B-tilde {sup 2}B{sub 2} excited states of H{sub 2}O{sup +}. Comparison with D{sub 2}O absorption and ionization yields, derived from Katayama et al (1973 J. Chem. Phys. 59 4309), reveals specific energy-dependent deuteration effects on competitive predissociation and autoionization relaxation channels. Direct ionization was found to be only slightly affected by deuteration.

  11. Constituents’ formal participation in the IASB’s due process: New insights into the impact of country and due process document characteristics

    Directory of Open Access Journals (Sweden)

    Michael Dobler

    2016-09-01

    Full Text Available This paper adopts a multi-issue/multi-period approach to provide new insights into key determinants of constituents’ formal participation in the due process of the International Accounting Standards Board (IASB. Based on an analysis of 8,825 comment letters submitted during the period 2006–2012, we find imbalances in the representation of constituents. Multiple regressions reveal that among various economic and cultural variables equity market capitalization and the society’s level of individualism are the key drivers of the country-level of constituents’ participation, and each variable has explanatory power over the other. The level of constituents’ participation is positively associated with the number of input opportunities offered by a due process document but unrelated to the complexity of a standard-setting project. The results are robust across various sub-samples and to additional sensitivity tests. Our findings indicate threats to the input legitimacy of the IASB and suggest avenues to stimulate constituents’ participation.

  12. Electron spin-lattice relaxation in fractals

    International Nuclear Information System (INIS)

    Shrivastava, K.N.

    1986-08-01

    We have developed the theory of the spin-fracton interaction for paramagnetic ions in fractal structures. The interaction is exponentially damped by the self-similarity length of the fractal and by the range dimensionality d Φ . The relaxation time of the spin due to the absorption and emission of the fracton has been calculated for a general dimensionality called the Raman dimensionality d R , which for the fractons differs from the Hausdorff (fractal) dimensionality, D, as well as from the Euclidean dimensionality, d. The exponent of the energy level separation in the relaxation rate varies with d R d Φ /D. We have calculated the spin relaxation rate due to a new type of Raman process in which one fracton is absorbed to affect a spin transition from one electronic level to another and later another fracton is emitted along with a spin transition such that the difference in the energies of the two fractons is equal to the electronic energy level separation. The temperature and the dimensionality dependence of such a process has been found in several approximations. In one of the approximations where the van Vleck relaxation rate for a spin in a crystal is known to vary with temperature as T 9 , our calculated variation for fractals turns out to be T 6.6 , whereas the experimental value for Fe 3+ in frozen solutions of myoglobin azide is T 6.3 . Since we used d R =4/3 and the fracton range dimensionality d Φ =D/1.8, we expect to measure the dimensionalities of the problem by measuring the temperature dependence of the relaxation times. We have also calculated the shift of the paramagnetic resonance transition for a spin in a fractal for general dimensionalities. (author)

  13. Actuality the process of relaxation on the lessons of physical training on the current stage of higher education

    Directory of Open Access Journals (Sweden)

    Vankova A.U.

    2010-04-01

    Full Text Available Facilities are considered of making healthy for the improvement of ability to resist stress situations of students. Engaged in a physical culture in the net of educational clock must be conducted in the institute of higher before and after the special disciplines. Application of method of relaxation together with musical accompaniment promote claim of higher type of pedagogical organization of employments. A chronic mental overstrain without the sufficient physical discharging results in a nervous overstrain, negative emotions, deficit of time, violation of the mode of labour and rest, reduction of possibility of physical activity.

  14. Extended Thermodynamics of Rarefied Polyatomic Gases: 15-Field Theory Incorporating Relaxation Processes of Molecular Rotation and Vibration

    Directory of Open Access Journals (Sweden)

    Takashi Arima

    2018-04-01

    Full Text Available After summarizing the present status of Rational Extended Thermodynamics (RET of gases, which is an endeavor to generalize the Navier–Stokes and Fourier (NSF theory of viscous heat-conducting fluids, we develop the molecular RET theory of rarefied polyatomic gases with 15 independent fields. The theory is justified, at mesoscopic level, by a generalized Boltzmann equation in which the distribution function depends on two internal variables that take into account the energy exchange among the different molecular modes of a gas, that is, translational, rotational, and vibrational modes. By adopting the generalized Bhatnagar, Gross and Krook (BGK-type collision term, we derive explicitly the closed system of field equations with the use of the Maximum Entropy Principle (MEP. The NSF theory is derived from the RET theory as a limiting case of small relaxation times via the Maxwellian iteration. The relaxation times introduced in the theory are shown to be related to the shear and bulk viscosities and heat conductivity.

  15. Internal structures of self-organized relaxed states and self-similar decay phase

    International Nuclear Information System (INIS)

    Kondoh, Yoshiomi

    1992-03-01

    A thought analysis on relaxation due to nonlinear processes is presented to lead to a set of general thoughts applicable to general nonlinear dynamical systems for finding out internal structures of the self-organized relaxed state without using 'invariant'. Three applications of the set of general thoughts to energy relaxations in resistive MHD plasmas, incompressible viscous fluids, and incompressible viscous MHD fluids are shown to lead to the internal structures of the self-organized relaxed states. It is shown that all of the relaxed states in these three dynamical systems are followed by self-similar decay phase without significant change of the spatial structure. The well known relaxed state of ∇ x B = ±λ B is shown to be derived generally in the low β plasma limit. (author)

  16. Relaxed states of tokamak plasmas

    International Nuclear Information System (INIS)

    Kucinski, M.Y.; Okano, V.

    1993-01-01

    The relaxed states of tokamak plasmas are studied. It is assumed that the plasma relaxes to a quasi-steady state which is characterized by a minimum entropy production rate, compatible with a number of prescribed conditions and pressure balance. A poloidal current arises naturally due to the anisotropic resistivity. The minimum entropy production theory is applied, assuming the pressure equilibrium as fundamental constraint on the final state. (L.C.J.A.)

  17. Due Process in the Internet Jurisdiction: Landing Softly on the Other Side of the Looking Glass

    National Research Council Canada - National Science Library

    Kolb, Natalie A

    2001-01-01

    .... However, even if a U.S. state court exercises improper jurisdiction over a non-resident defendant in an Internet case, due process protection can be revived at the choice-of-law and enforcement stages of the judicial proceeding...

  18. A Longitudinal Study of Special Education Due Process Hearings in Massachusetts

    Directory of Open Access Journals (Sweden)

    William H. Blackwell

    2015-03-01

    Full Text Available Of the three formal dispute resolution procedures provided by the Individuals With Disabilities Education Act of 2004(IDEA, due process hearings are the most costly in terms of time, fiscal resources, and impact on relationships between school personnel and parents. This study examined 258 due process hearings held over the past 8 years in Massachusetts to examine the characteristics of students at the center of these disputes, the issues that were addressed in the hearings, and the representation utilized by parents and school districts. The findings from this study indicated that (a Massachusetts school districts utilized attorney representation and won due process hearings at notably higher levels than parents, and (b the most frequently addressed issues at due process hearings were Individualized Education Program (IEP development/implementation and educational program placement, which are issues that represent the core mandate of IDEA to provide a free appropriate public education in the least restrictive environment (34 C.F.R. §300.300, 300.550. The authors present recommendations for policy actions and areas for future research.

  19. Effects of surveillance on the rule of law, due process and the presumption of innocence

    NARCIS (Netherlands)

    Galetta, Antonella; de Hert, Paul; Wright, D.; Kreissl, R.

    2015-01-01

    This contribution focuses on the impact of surveillance on the rule of law, due process and the presumption of innocence, key values and principles of a democratic order. It illustrates how they are implemented and enforced in contemporary surveillance societies, while referring to European law and

  20. Due Process and Higher Education: A Systemic Approach to Fair Decision Making. ERIC Digest.

    Science.gov (United States)

    Stevens, Ed

    University officials and faculty are frequently required to make decisions based on interpretations of disputed facts. By applying the concept of due process within the context of higher education, they can meet legal challenges of contract and constitutional law and the pedagogical demand for justice. To guide their efforts, decision makers can…

  1. The Procedural Queer: Substantive Due Process, "Lawrence v. Texas," and Queer Rhetorical Futures

    Science.gov (United States)

    Campbell, Peter Odell

    2012-01-01

    This essay discusses Justice Anthony M. Kennedy's choice to foreground arguments from due process rather than equal protection in the majority opinion in Lawrence v. Texas. Kennedy's choice can realize constitutional legal doctrine that is more consistent with radical queer politics than arguments from equal protection. Unlike some recent…

  2. Formal participation in the IASB's due process of standard setting : A multi-issue/multiperiod analysis

    NARCIS (Netherlands)

    Jorissen, A.; Lybaert, N.; Orens, R.; van der Tas, L.G.

    2012-01-01

    This paper sets out to enquire about the nature of constituents' participation in the IASB's due process in terms of representation (constituents' diversity and characteristics) and drivers to participate. We choose to adopt a multi-issue/multi-period approach to investigate constituents' formal

  3. Divided-evolution-based pulse scheme for quantifying exchange processes in proteins: powerful complement to relaxation dispersion experiments.

    Science.gov (United States)

    Bouvignies, Guillaume; Hansen, D Flemming; Vallurupalli, Pramodh; Kay, Lewis E

    2011-02-16

    A method for quantifying millisecond time scale exchange in proteins is presented based on scaling the rate of chemical exchange using a 2D (15)N, (1)H(N) experiment in which (15)N dwell times are separated by short spin-echo pulse trains. Unlike the popular Carr-Purcell-Meiboom-Gill (CPMG) experiment where the effects of a radio frequency field on measured transverse relaxation rates are quantified, the new approach measures peak positions in spectra that shift as the effective exchange time regime is varied. The utility of the method is established through an analysis of data recorded on an exchanging protein-ligand system for which the exchange parameters have been accurately determined using alternative approaches. Computations establish that a combined analysis of CPMG and peak shift profiles extends the time scale that can be studied to include exchanging systems with highly skewed populations and exchange rates as slow as 20 s(-1).

  4. Study of relaxation processes in 'metal-ligand' complexes after electron capture decay using the 111In isotope as an example

    International Nuclear Information System (INIS)

    Shpinkova, L.G.; Golubeva, A.S.; Ryasny, O.K.; Nikitin, S.M.; Sorokin, A.A.; Uzbyakova, A.S.

    2003-01-01

    Full text: Complexes of metals with organic ligands are widely used in different scientific and industrial applications, such as analytical chemistry, oil production and refinery, power engineering, water treatment, agriculture, etc. Several hundred complexes are commercially available and there are still intensive works on synthesizing new complexones in order to obtain complexes with required properties. In this connection, it is important to investigate the molecular characteristics of complexes and their structures and correlate with their properties. One of the methods, which proved to provide useful information about metal-ligand complexes behaviour, is the method of time differential perturbed angular γγ-correlation (Tdpa). Numerous works have been devoted to studies of different complexes by this technique. In the Inst. of Nuclear Physics, Lomonosov Moscow State Univ., Moscow, this method was applied to studies of electron capture (EC) after-effects and their influence on the indium-ligand complexes in aqueous solutions. The present work is devoted to studies of relaxation processes in daughter 111 Cd-ligand complexes formed after 111 In EC decay. EC leaves a hole in an inner electronic shell of the daughter atom, which is followed by Auger-process. This process leads to a highly excited state of a daughter atom, which either causes disintegration of a complex into small fragments or relaxation to a stable complex with the daughter atom. TDPAC measurements were performed for a number of 111 In-complexes with acetic and phosphonic ligands. All measurements were performed for neutral aqueous solutions of complexes at room temperature. Three types of molecules containing radioactive daughter 11C d atoms were observed after 111 In decay for all studied complexes. One fraction corresponds to the intact complexes, the second one - to fully disintegrated complexes. The third fraction was characterized by a fast relaxation parameter indicating high transient

  5. Steepest-entropy-ascent quantum thermodynamic modeling of the relaxation process of isolated chemically reactive systems using density of states and the concept of hypoequilibrium state

    Science.gov (United States)

    Li, Guanchen; von Spakovsky, Michael R.

    2016-01-01

    This paper presents a study of the nonequilibrium relaxation process of chemically reactive systems using steepest-entropy-ascent quantum thermodynamics (SEAQT). The trajectory of the chemical reaction, i.e., the accessible intermediate states, is predicted and discussed. The prediction is made using a thermodynamic-ensemble approach, which does not require detailed information about the particle mechanics involved (e.g., the collision of particles). Instead, modeling the kinetics and dynamics of the relaxation process is based on the principle of steepest-entropy ascent (SEA) or maximum-entropy production, which suggests a constrained gradient dynamics in state space. The SEAQT framework is based on general definitions for energy and entropy and at least theoretically enables the prediction of the nonequilibrium relaxation of system state at all temporal and spatial scales. However, to make this not just theoretically but computationally possible, the concept of density of states is introduced to simplify the application of the relaxation model, which in effect extends the application of the SEAQT framework even to infinite energy eigenlevel systems. The energy eigenstructure of the reactive system considered here consists of an extremely large number of such levels (on the order of 10130) and yields to the quasicontinuous assumption. The principle of SEA results in a unique trajectory of system thermodynamic state evolution in Hilbert space in the nonequilibrium realm, even far from equilibrium. To describe this trajectory, the concepts of subsystem hypoequilibrium state and temperature are introduced and used to characterize each system-level, nonequilibrium state. This definition of temperature is fundamental rather than phenomenological and is a generalization of the temperature defined at stable equilibrium. In addition, to deal with the large number of energy eigenlevels, the equation of motion is formulated on the basis of the density of states and a set of

  6. Glass transition and relaxation dynamics of propylene glycol-water solutions confined in clay

    Science.gov (United States)

    Elamin, Khalid; Björklund, Jimmy; Nyhlén, Fredrik; Yttergren, Madeleine; Mârtensson, Lena; Swenson, Jan

    2014-07-01

    The molecular dynamics of aqueous solutions of propylene glycol (PG) and propylene glycol methylether (PGME) confined in a two-dimensional layer-structured Na-vermiculite clay has been studied by broadband dielectric spectroscopy and differential scanning calorimetry. As typical for liquids in confined geometries the intensity of the cooperative α-relaxation becomes considerably more suppressed than the more local β-like relaxation processes. In fact, at high water contents the calorimetric glass transition and related structural α-relaxation cannot even be observed, due to the confinement. Thus, the intensity of the viscosity related α-relaxation is dramatically reduced, but its time scale as well as the related glass transition temperature Tg are for both systems only weakly influenced by the confinement. In the case of the PGME-water solutions it is an important finding since in the corresponding bulk system a pronounced non-monotonic concentration dependence of the glass transition related dynamics has been observed due to the growth of hydrogen bonded relaxing entities of water bridging between PGME molecules [J. Sjöström, J. Mattsson, R. Bergman, and J. Swenson, Phys. Chem. B 115, 10013 (2011)]. The present results suggest that the same type of structural entities are formed in the quasi-two-dimensional space between the clay platelets. It is also observed that the main water relaxation cannot be distinguished from the β-relaxation of PG or PGME in the concentration range up to intermediate water contents. This suggests that these two processes are coupled and that the water molecules affect the time scale of the β-relaxation. However, this is most likely true also for the corresponding bulk solutions, which exhibit similar time scales of this combined relaxation process below Tg. Finally, it is found that at higher water contents the water relaxation does not merge with, or follow, the α-relaxation above Tg, but instead crosses the α-relaxation

  7. Characterization of the Ionic Liquid/Electrode Interfacial Relaxation Processes Under Potential Polarization for Ionic Liquid Amperometric Gas Sensor Method Development.

    Science.gov (United States)

    Lin, Lu; Zhao, Peng; Mason, Andrew J; Zeng, Xiangqun

    2018-06-04

    Electrochemical amperometric sensors require a constant or varying potential at the working electrode that drives redox reactions of the analyte for detection. The interfacial redox reaction(s) can result in the formation of new chemical products that could change the initial condition of the electrode/electrolyte interface. If the products are not inert and/or cannot be removed from the system such that the initial condition of the electrode/electrolyte interface cannot be restored, the sensor signal baseline would consequently drift, which is problematic for the continuous and real-time sensors. By setting the electrode potential with the periodical ON-OFF mode, electrolysis can be forestalled during the off mode which can minimize the sensor signal baseline drift and reduce the power consumption of the sensor. However, it is known that the relaxation of the structure in the electrical double layer at the ionic liquid/electrode interface to the steps of the electrode potential is slow. This work characterized the electrode/electrolyte interfacial relaxation process of an ionic liquid based electrochemical gas (IL-EG) sensor by performing multiple potential step experiments in which the potential is stepped from an open circuit potential (OCP) to the amperometric sensing potential at various frequencies with different time periods. Our results showed that by shortening the sensing period as well as extending the idle period (i.e., enlarge the ratio of idle period versus sensing period) of the potential step experiments, the electrode/electrolyte interface is prone to relax to its original state, and thus reduces the baseline drift. Additionally, the high viscosity of the ionic liquids is beneficial for electrochemical regeneration via the implementation of a conditioning step at zero volts at the electrode/electrolyte. By setting the working electrode at zero volts instead of OCP, our results showed that it could further minimize the baseline drift, enhance the

  8. Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone−ethylene glycol blends

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The dielectric dispersion behaviour of montmorillonite (MMT clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone-ethylene glycol (PVP-EG blends were investigated over the frequency range 20 Hz to 1 MHz at 30°C. The 0, 1, 2, 3, 5 and 10 wt% MMT clay concentration of the weight of total solute (MMT+PVP were prepared in PVP-EG blends using EG as solvent. The complex relative dielectric function, alternating current (ac electrical conductivity, electric modulus and impedance spectra of these materials show the relaxation processes corresponding to the micro-Brownian motion of PVP chain, ion conduction and electrode polarization phenomena. The real part of ac conductivity spectra of these materials obeys Jonscher power law σ′(ω =σdc + Aωn in upper frequency end of the measurement, whereas dispersion in lower frequency end confirms the presence of electrode polarization effect. It was observed that the increase of clay concentration in the PVP-EG blends significantly increases the ac conductivity values, and simultaneously reduces the ionic conductivity relaxation time and electric double layer relaxation time, which suggests that PVP segmental dynamics and ionic motion are strongly coupled. The intercalation of EG structures in clay galleries and exfoliation of clay sheets by adsorption of PVP-EG structures on clay surfaces are discussed by considering the hydrogen bonding interactions between the hydroxyl group (–OH of EG molecules, carbonyl group (C=O of PVP monomer units, and the hydroxylated aluminate surfaces of the MMT clay particles. Results suggest that the colloidal suspension of MMT clay nano particles in the PVP-EG blends provide a convenient way to obtain an electrolyte solution with tailored electrical conduction properties.

  9. Insights into the IASB due process: the influence of country characteristics on constituents’ formal participation

    Directory of Open Access Journals (Sweden)

    Karsten Eisenschmidt

    2017-12-01

    Full Text Available The paper explores the impact of country characteristics on constituents’ formal participation in the IASB’s due process. We hypothesize that there is an association between the level of constituents’ partic- ipation and (1 the level of economic development, and (2 the cultural characteristics of the country of origin. We use a number of comment letters (CLs and their length as proxies for constituents’ formal participation in the IASB’s due process. The results indicate that economic development (equity market capitalization is the most important explanatory factor for the different levels of participation. In con- trast, the cultural characteristics measured by Hofstede’s cultural framework can only partially explain that differences. Only individualism is a significant positive influence factor for the level of constituents’ participation. The results of our descriptive analysis for the CLs and the information input provided show that there is still a lack of participation in the IASB’s due process. Despite the huge impact of accounting norms on societies, only a limited number of constituents participate, and some constituent groups, like users or academics, participate less.

  10. Sandpile model for relaxation in complex systems

    International Nuclear Information System (INIS)

    Vazquez, A.; Sotolongo-Costa, O.; Brouers, F.

    1997-10-01

    The relaxation in complex systems is, in general, nonexponential. After an initial rapid decay the system relaxes slowly following a long time tail. In the present paper a sandpile moderation of the relaxation in complex systems is analysed. Complexity is introduced by a process of avalanches in the Bethe lattice and a feedback mechanism which leads to slower decay with increasing time. In this way, some features of relaxation in complex systems: long time tails relaxation, aging, and fractal distribution of characteristic times, are obtained by simple computer simulations. (author)

  11. Defective motion processing in children with cerebral visual impairment due to periventricular white matter damage.

    Science.gov (United States)

    Weinstein, Joel M; Gilmore, Rick O; Shaikh, Sumera M; Kunselman, Allen R; Trescher, William V; Tashima, Lauren M; Boltz, Marianne E; McAuliffe, Matthew B; Cheung, Albert; Fesi, Jeremy D

    2012-07-01

    We sought to characterize visual motion processing in children with cerebral visual impairment (CVI) due to periventricular white matter damage caused by either hydrocephalus (eight individuals) or periventricular leukomalacia (PVL) associated with prematurity (11 individuals). Using steady-state visually evoked potentials (ssVEP), we measured cortical activity related to motion processing for two distinct types of visual stimuli: 'local' motion patterns thought to activate mainly primary visual cortex (V1), and 'global' or coherent patterns thought to activate higher cortical visual association areas (V3, V5, etc.). We studied three groups of children: (1) 19 children with CVI (mean age 9y 6mo [SD 3y 8mo]; 9 male; 10 female); (2) 40 neurologically and visually normal comparison children (mean age 9y 6mo [SD 3y 1mo]; 18 male; 22 female); and (3) because strabismus and amblyopia are common in children with CVI, a group of 41 children without neurological problems who had visual deficits due to amblyopia and/or strabismus (mean age 7y 8mo [SD 2y 8mo]; 28 male; 13 female). We found that the processing of global as opposed to local motion was preferentially impaired in individuals with CVI, especially for slower target velocities (p=0.028). Motion processing is impaired in children with CVI. ssVEP may provide useful and objective information about the development of higher visual function in children at risk for CVI. © The Authors. Journal compilation © Mac Keith Press 2011.

  12. Induced Current Characteristics Due to Laser Induced Plasma and Its Application to Laser Processing Monitoring

    International Nuclear Information System (INIS)

    Madjid, Syahrun Nur; Idris, Nasrullah; Kurniawan, Koo Hendrik; Kagawa, Kiichiro

    2011-01-01

    In laser processing, suitable conditions for laser and gas play important role in ensuring a high quality of processing. To determine suitable conditions, we employed the electromagnetic phenomena associated with laser plasma generation. An electrode circuit was utilised to detect induced current due to the fast electrons propelled from the material during laser material processing. The characteristics of induced current were examined by changing parameters such as supplied voltage, laser pulse energy, number of laser shots, and type of ambient gas. These characteristics were compared with the optical emission characteristics. It was shown that the induced current technique proposed in this study is much more sensitive than the optical method in monitoring laser processing, that is to determine the precise focusing condition, and to accurately determine the moment of completion of laser beam penetration. In this study it was also shown that the induced current technique induced by CW CO 2 laser can be applied in industrial material processing for monitoring the penetration completion in a stainless steel plate drilling process.

  13. Tube failures due to cooling process problem and foreign materials in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, J. [Kapar Energy Ventures Sdn Bhd, Jalan Tok Muda, Kapar 42200 (Malaysia); Purbolaksono, J., E-mail: judha@uniten.edu.m [Department of Mechanical Engineering, Universiti Tenaga Nasional, Km 7 Jalan Kajang-Puchong, Kajang 43009, Selangor (Malaysia); Beng, L.C. [Kapar Energy Ventures Sdn Bhd, Jalan Tok Muda, Kapar 42200 (Malaysia)

    2010-07-15

    Cooling process which uses water for heat transfer is an essential factor in coal-fired and nuclear plants. Loss of cooling upset can force the plants to shut down. In particular, this paper reports visual inspections and metallurgical examinations on the failed SA210-A1 right-hand side (RHS) water wall tube of a coal-fired plant. The water wall tube showed the abnormal outer surface colour and has failed with wide-open ductile rupture and thin edges indicating typical signs of short-term overheating. Metallurgical examinations confirmed the failed tube experiencing higher temperature operation. Water flow starvation due to restriction inside the upstream tube is identified as the main root cause of failure. The findings are important to take failure mitigation actions in the future operation. Discussion on the typical problems related to the cooling process in nuclear power plants is also presented.

  14. Tube failures due to cooling process problem and foreign materials in power plants

    International Nuclear Information System (INIS)

    Ahmad, J.; Purbolaksono, J.; Beng, L.C.

    2010-01-01

    Cooling process which uses water for heat transfer is an essential factor in coal-fired and nuclear plants. Loss of cooling upset can force the plants to shut down. In particular, this paper reports visual inspections and metallurgical examinations on the failed SA210-A1 right-hand side (RHS) water wall tube of a coal-fired plant. The water wall tube showed the abnormal outer surface colour and has failed with wide-open ductile rupture and thin edges indicating typical signs of short-term overheating. Metallurgical examinations confirmed the failed tube experiencing higher temperature operation. Water flow starvation due to restriction inside the upstream tube is identified as the main root cause of failure. The findings are important to take failure mitigation actions in the future operation. Discussion on the typical problems related to the cooling process in nuclear power plants is also presented.

  15. Average thermal stress in the Al+SiC composite due to its manufacturing process

    International Nuclear Information System (INIS)

    Miranda, Carlos A.J.; Libardi, Rosani M.P.; Marcelino, Sergio; Boari, Zoroastro M.

    2013-01-01

    The numerical analyses framework to obtain the average thermal stress in the Al+SiC Composite due to its manufacturing process is presented along with the obtained results. The mixing of Aluminum and SiC powders is done at elevated temperature and the usage is at room temperature. A thermal stress state arises in the composite due to the different thermal expansion coefficients of the materials. Due to the particles size and randomness in the SiC distribution, some sets of models were analyzed and a statistical procedure used to evaluate the average stress state in the composite. In each model the particles position, form and size are randomly generated considering a volumetric ratio (VR) between 20% and 25%, close to an actual composite. The obtained stress field is represented by a certain number of iso stress curves, each one weighted by the area it represents. Systematically it was investigated the influence of: (a) the material behavior: linear x non-linear; (b) the carbide particles form: circular x quadrilateral; (c) the number of iso stress curves considered in each analysis; and (e) the model size (the number of particles). Each of above analyzed condition produced conclusions to guide the next step. Considering a confidence level of 95%, the average thermal stress value in the studied composite (20% ≤ VR ≤ 25%) is 175 MPa with a standard deviation of 10 MPa. Depending on its usage, this value should be taken into account when evaluating the material strength. (author)

  16. Due Diligence Processes for Public Acquisition of Mining-Impacted Landscapes

    Science.gov (United States)

    Martin, E.; Monohan, C.; Keeble-Toll, A. K.

    2016-12-01

    The acquisition of public land is critical for achieving conservation and habitat goals in rural regions projected to experience continuously high rates of population growth. To ensure that public funds are utilized responsibly in the purchase of conservation easements appropriate due diligence processes must be established that limit landowner liability post-acquisition. Traditional methods of characterizing contamination in regions where legacy mining activities were prevalent may not utilize current scientific knowledge and understanding of contaminant fate, transport and bioavailability, and therefore are likely to have type two error. Agency prescribed assessment methods utilized under CERLA in many cases fail to detect contamination that presents liability issues by failing to require water quality sampling that would reveal offsite transport potential of contaminants posing human health risks, including mercury. Historical analysis can be used to inform judgmental sampling to identify hotspots and contaminants of concern. Land acquisition projects at two historic mine sites in Nevada County, California, the Champion Mine Complex and the Black Swan Preserve have established the necessity of re-thinking due diligence processes for mining-impacted landscapes. These pilot projects demonstrate that pre-acquisition assessment in the Gold Country must include judgmental sampling and evaluation of contaminant transport. Best practices using the current scientific knowledge must be codified by agencies, consultants, and NGOs in order to ensure responsible use of public funds and to safeguard public health.

  17. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V.; Khandelwal, R.C.

    2010-01-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to 60 Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm 2 observed before decontamination

  18. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V., E-mail: svn@igcar.gov.in [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamilnadu (India); Khandelwal, R.C. [Kakrapara Atomic Power Station, KAPS, Surat, Gujarat (India)

    2010-07-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to {sup 60}Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm{sup 2} observed

  19. Breathing and Relaxation

    Science.gov (United States)

    ... Find a Doctor Relaxation is the absence of tension in muscle groups and a minimum or absence ... Drill Meditation Progressive Muscle Relaxation Minimizing Shortness of Breath Visualization This information has been approved by Shelby ...

  20. Relaxation property of the fractional Brownian particle

    International Nuclear Information System (INIS)

    Wang Litan; Lung, C.W.

    1988-08-01

    Dynamic susceptibility of a diffusion system associated with the fractional Brownian motion (fBm) was examined for the fractal property of the Non-Debye relaxation process. The comparisons between fBm and other approaches were made. Anomalous diffusion and the Non-Debye relaxation processes were discussed with this approach. (author). 8 refs, 1 fig

  1. 20 CFR 670.545 - How does Job Corps ensure that students receive due process in disciplinary actions?

    Science.gov (United States)

    2010-04-01

    ... receive due process in disciplinary actions? 670.545 Section 670.545 Employees' Benefits EMPLOYMENT AND... process in disciplinary actions? The center operator must ensure that all students receive due process in disciplinary proceedings according to procedures developed by the Secretary. These procedures must include, at...

  2. Mediation and Due Process Procedures in Special Education: An Analysis of State Policies. Final Report. Project FORUM.

    Science.gov (United States)

    Ahearn, Eileen M.

    This survey of 50 states and 3 of 10 non-state U.S. jurisdictions concerning state due process procedures focuses mainly on the use of mediation as a form of dispute resolution that offers an alternative to due process hearings in special education. A background section discusses the definition of mediation and the mediation process. Survey…

  3. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V.

    2011-01-01

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to 60 Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to Stellite particles with the radiation field ranging from 3 R . h -1 to 20 R . h -1 . They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000 decays per min and cm 2 observed

  4. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V. [BARC Facilities, Kalpakkam, Tamil Nadu (India). Water and Steam Chemistry Div.

    2011-06-15

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to {sup 60}Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to Stellite particles with the radiation field ranging from 3 R . h{sup -1} to 20 R . h{sup -1}. They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000

  5. Temperature resolution enhancing of commercially available THz passive cameras due to computer processing of images

    Science.gov (United States)

    Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Kuchik, Igor E.

    2014-06-01

    As it is well-known, application of the passive THz camera for the security problems is very promising way. It allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. Efficiency of using the passive THz camera depends on its temperature resolution. This characteristic specifies possibilities of the detection of concealed object: minimal size of the object, maximal distance of the detection, image detail. One of probable ways for a quality image enhancing consists in computer processing of image. Using computer processing of the THz image of objects concealed on the human body, one may improve it many times. Consequently, the instrumental resolution of such device may be increased without any additional engineering efforts. We demonstrate new possibilities for seeing the clothes details, which raw images, produced by the THz cameras, do not allow to see. We achieve good quality of the image due to applying various spatial filters with the aim to demonstrate independence of processed images on math operations. This result demonstrates a feasibility of objects seeing. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp., and Capital Normal University (Beijing, China).

  6. Adaptive memory: the survival-processing memory advantage is not due to negativity or mortality salience.

    Science.gov (United States)

    Bell, Raoul; Röer, Jan P; Buchner, Axel

    2013-05-01

    Recent research has highlighted the adaptive function of memory by showing that imagining being stranded in the grasslands without any survival material and rating words according to their survival value in this situation leads to exceptionally good memory for these words. Studies examining the role of emotions in causing the survival-processing memory advantage have been inconclusive, but some studies have suggested that the effect might be due to negativity or mortality salience. In Experiments 1 and 2, we compared the survival scenario to a control scenario that implied imagining a hopeless situation (floating in outer space with dwindling oxygen supplies) in which only suicide can avoid the agony of choking to death. Although this scenario was perceived as being more negative than the survival scenario, the survival-processing memory advantage persisted. In Experiment 3, thinking about the relevance of words for survival led to better memory for these words than did thinking about the relevance of words for death. This survival advantage was found for concrete, but not for abstract, words. The latter finding is consistent with the assumption that the survival instructions encourage participants to think about many different potential uses of items to aid survival, which may be a particularly efficient form of elaborate encoding. Together, the results suggest that thinking about death is much less effective in promoting recall than is thinking about survival. Therefore, the survival-processing memory advantage cannot be satisfactorily explained by negativity or mortality salience.

  7. Dielectric relaxations above room temperature in DMPU derived polyaniline film

    International Nuclear Information System (INIS)

    Mallya, Ashwini N.; Yashavanth Kumar, G.S.; Ranjan, Rajeev; Ramamurthy, Praveen C.

    2012-01-01

    Dielectric measurements carried out on drop casted from solution of emeraldine base form of polyaniline films in the temperature range 30-300 °C revealed occurrence of two maxima in the loss tangent as a function of temperature. The activation energies corresponding to these two relaxation processes were found to be ∼0.5 eV and ∼1.5 eV. The occurrence of one relaxation peak in the dispersion curve of the imaginary part of the electric modulus suggests the absence of microphase separation in the film. Thermogravimetric analysis and infrared spectroscopic measurements showed that the films retained its integrity up to 300 °C. The dielectric relaxation at higher temperatures with large activation energy of 1.5 eV is attributed to increase in the barrier potential due to decrease in the polymer conjugation as a result of wide amplitude motion of the chain segments well above the glass transition temperature.

  8. Accommodaton of constitutional due process rights within the new patients' rights legislation in Slovenia.

    Science.gov (United States)

    Ivanc, Blaz

    2011-09-01

    The Constitutional Court of the Republic of Slovenia issued several decisions concerning the protection of patients' rights (e.g. decisions on involuntary commitment, on access to health care, on rights related to obligatory and voluntary health insurance). Consequently, the Parliament renewed Health Legislation by the enactment of the Patients' Rights Act (February 2008) and of the Mental Health Act (July 2008). Both bills enshrine a charter of patients' rights that may be considered as concretization of several human rights that are protected by the Constitution. The discussion is focused on the due process rights (e.g. equal protection of rights, right to judicial protection, right to legal remedies, legal guarantees in proceedings related to deprivation of personal liberty) that were in particular addressed by the Court. The results demonstrate that their effective implementation was one of the most important demands that the Legislature had to accommodate when enacting new bills.

  9. South African, Rural ICT Implementation: a critical retrospective application of Latour's due process model

    Directory of Open Access Journals (Sweden)

    Jo Rhodes

    2004-05-01

    Full Text Available The potential developmental role of ICTs can pressurise governments to engage in ‘catch up’ and ‘leapfrog’. Consequently, analysis of the accompanying socio-political dimensions and risks can be, disastrously, neglected. This paper examines a specific technology implementation – a South African government sponsored telecentre using Latour’s Due Process model, an analytical tool grounded in Actor-Network Theory, where technology implementation is viewed as a symmetrical treatment of technology and society within a single collective. It is used here, retrospectively, to make sense of why the telecentre both failed to institutionalise within a successful actor-network, and, contributed to the destabilization and partial destruction of a successfully established women’s development organisation.

  10. Research Amplitudo Vibration On Holder Due To The Process Of Lathe Nozzle Rocket RX 450

    Science.gov (United States)

    Ediwan; Budi Djatmiko, Agus; Dody Arisandi, EfFendy; Purnomo, Heri; Ibadi, Mahfud

    2018-04-01

    The main function of the rocket nozzle is to convert the enthalpy efficiency from combustion gas to kinetic energy and also to make high velocity out of the gas. The rocket nozzle usually consists of a converging and diverging part. With a smaller area on the neck and enlarged at the exit area. The velocity flow through the nozzle enlarges into the speed of sound through the neck and then becomes super sonic in the divergent part. Nozzle making or machining using conventional lathes, first performed is drilling on a massive metal that is bonded to the veneer, then after a sufficient gap is done deep-boring. At the time of the process of lathe in the nozzle RX 450 there is an obstacle that is vibrating tool holder chisel or holder so it is worried about not precision of the process of lathe. This should not happen because it can cause failure in the latter for it needs to be studied and studied further so that the lathe process goes accordingly. The holder material of ST 60 with a modulus of elasticity 200 GPa and a nozzle material of AISI 4340 alloy steel with σyield = 470 MPa, Shear Modulus G = 80 GPa. The purpose of this research is to observe the amplitude of vibration on the holder due to RX- 450 nozzle lathe processing for the purpose of amplitude that occurs in accordance with the desired so that the nozzle structure is no damage process. The result of the research was obtained holder with length (L) 80cm, profile width (B) 5 cm, height of profile (H) 10 cm, turning machine ω = 8.98 rad / sec and natural holder frequency ωn = 89.8 rad / second, Amplitude of vibration of δ = 1.21 mm, while the amplitude of the design X = 1.22 mm From the results of this study it can be said that the holder of a chisel or holder can be used as a tool at the time of RX nozzle retrieval process and is quite safe because it works under the condition ω/ω n Rocket Payload "AKPV Engineering University of Wyoming 2009 )

  11. Parameterization of NMR relaxation curves in terms of logarithmic moments of the relaxation time distribution.

    Science.gov (United States)

    Petrov, Oleg V; Stapf, Siegfried

    2017-06-01

    This work addresses the problem of a compact and easily comparable representation of multi-exponential relaxation data. It is often convenient to describe such data in a few parameters, all being of physical significance and easy to interpret, and in such a way that enables a model-free comparison between different groups of samples. Logarithmic moments (LMs) of the relaxation time constitute a set of parameters which are related to the characteristic relaxation time on the log-scale, the width and the asymmetry of an underlying distribution of exponentials. On the other hand, the calculation of LMs does not require knowing the actual distribution function and is reduced to a numerical integration of original data. The performance of this method has been tested on both synthetic and experimental NMR relaxation data which differ in a signal-to-noise ratio, the sampling range and the sampling rate. The calculation of two lower-order LMs, the log-mean time and the log-variance, has proved robust against deficiencies of the experiment such as scattered data point and incomplete sampling. One may consider using them as such to monitor formation of a heterogeneous structure, e.g., in phase separation, vitrification, polymerization, hydration, aging, contrast agent propagation processes. It may also assist in interpreting frequency and temperature dependences of relaxation, revealing a crossover from slow to fast exchange between populations. The third LM was found to be a less reliable quantity due to its susceptibility to the noise and must be used with caution. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Parameterization of NMR relaxation curves in terms of logarithmic moments of the relaxation time distribution

    Science.gov (United States)

    Petrov, Oleg V.; Stapf, Siegfried

    2017-06-01

    This work addresses the problem of a compact and easily comparable representation of multi-exponential relaxation data. It is often convenient to describe such data in a few parameters, all being of physical significance and easy to interpret, and in such a way that enables a model-free comparison between different groups of samples. Logarithmic moments (LMs) of the relaxation time constitute a set of parameters which are related to the characteristic relaxation time on the log-scale, the width and the asymmetry of an underlying distribution of exponentials. On the other hand, the calculation of LMs does not require knowing the actual distribution function and is reduced to a numerical integration of original data. The performance of this method has been tested on both synthetic and experimental NMR relaxation data which differ in a signal-to-noise ratio, the sampling range and the sampling rate. The calculation of two lower-order LMs, the log-mean time and the log-variance, has proved robust against deficiencies of the experiment such as scattered data point and incomplete sampling. One may consider using them as such to monitor formation of a heterogeneous structure, e.g., in phase separation, vitrification, polymerization, hydration, aging, contrast agent propagation processes. It may also assist in interpreting frequency and temperature dependences of relaxation, revealing a crossover from slow to fast exchange between populations. The third LM was found to be a less reliable quantity due to its susceptibility to the noise and must be used with caution.

  13. Interaction of iron with boron in metal-rich metallaboranes resulting in large deshielding and rapid relaxation processes of the boron-11 nucleus

    International Nuclear Information System (INIS)

    Rath, N.P.; Fehlner, T.P.

    1988-01-01

    A first-order, parameterized model for calculating 11 B chemical shifts in metal-rich ferraboranes and a correlation of chemical shift with boron Mulliken populations from Fenske-Hall calculations are presented. These correlations are qualitatively different from those reported earlier for boranes and suggest that direct iron-boron interactions lead to large deshielding due to substantial increases in multiple-bond contributions to the shielding tensor. Relaxation rates have been measured for [Fe 4 (CO) 12 BH/sub 3-n/]/sup n-/ (n = 0-2) and correlated with electric field gradients at the boron nucleus estimated from Fenske-Hall calculations. These results demonstrate that formation of the boride, [Fe 4 (CO) 12 B] 3- , by deprotonation is accompanied by the development of large asymmetries in the electronic charge distribution around the boron nucleus. Finally, 7 Li NMR is used to probe the nature of the anions [Fe 4 (CO) 12 BH/sub 3-n/]/sup n-/ (n = 1-3), and observed line shapes suggest close association of Li + with the trianion. 28 references, 3 figures, 4 tables

  14. Investigation of structural relaxation, crystallization process and magnetic properties of the Fe-Ni-Si-B-C amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kalezic-Glisovic, A. [Joint Laboratory for Advanced Materials of SASA, Section for Amorphous Systems, Technical Faculty Cacak, Svetog Save 65, 32000 Cacak (Serbia and Montenegro)]. E-mail: aleksandrakalezic@eunet.yu; Novakovic, L. [Faculty of Physics, Studentski trg 16, 11000 Belgrade (Serbia and Montenegro); Maricic, A. [Joint Laboratory for Advanced Materials of SASA, Section for Amorphous Systems, Technical Faculty Cacak, Svetog Save 65, 32000 Cacak (Serbia and Montenegro); Minic, D. [Faculty of Physical Chemistry, Studentski trg 16, 11000 Belgrade (Serbia and Montenegro); Mitrovic, N. [Joint Laboratory for Advanced Materials of SASA, Section for Amorphous Systems, Technical Faculty Cacak, Svetog Save 65, 32000 Cacak (Serbia and Montenegro)]. E-mail: nmitrov@tfc.kg.ac.yu

    2006-07-15

    The differential scanning calorimetry method was used for investigating the crystallization process of the Fe{sub 89.8}Ni{sub 1.5}Si{sub 5.2}B{sub 3}C{sub 0.5} amorphous alloy. It was shown that the examined alloy crystallizes in three stages. The first crystallization stage occurs at 799 K, the second at 820 K and the third at 888 K. Temperature dependence of the magnetic susceptibility relative change was investigated by the modified Faraday method in the temperature region from room temperature up to 900 K. It has been established that the Curie temperature is about 700 K for amorphous state. The magnetic susceptibility increases by 30% after the first heating up to 710 K. During the second heating up to 840 K the alloy loses its ferromagnetic features in the temperature region from 710 to 750 K, upon which it again regains the same. After the second heating magnetic susceptibility decreases by 23% as compared to the amorphous starting value and by 53% as compared to the value before the second heating. The crystallized alloy maintains ferromagnetic features in the whole temperature region during the heating up to 900 K.

  15. Investigation of structural relaxation, crystallization process and magnetic properties of the Fe-Ni-Si-B-C amorphous alloy

    International Nuclear Information System (INIS)

    Kalezic-Glisovic, A.; Novakovic, L.; Maricic, A.; Minic, D.; Mitrovic, N.

    2006-01-01

    The differential scanning calorimetry method was used for investigating the crystallization process of the Fe 89.8 Ni 1.5 Si 5.2 B 3 C 0.5 amorphous alloy. It was shown that the examined alloy crystallizes in three stages. The first crystallization stage occurs at 799 K, the second at 820 K and the third at 888 K. Temperature dependence of the magnetic susceptibility relative change was investigated by the modified Faraday method in the temperature region from room temperature up to 900 K. It has been established that the Curie temperature is about 700 K for amorphous state. The magnetic susceptibility increases by 30% after the first heating up to 710 K. During the second heating up to 840 K the alloy loses its ferromagnetic features in the temperature region from 710 to 750 K, upon which it again regains the same. After the second heating magnetic susceptibility decreases by 23% as compared to the amorphous starting value and by 53% as compared to the value before the second heating. The crystallized alloy maintains ferromagnetic features in the whole temperature region during the heating up to 900 K

  16. Evidences of landslide earthquake triggering due to self-excitation process

    Science.gov (United States)

    Bozzano, F.; Lenti, L.; Martino, Salvatore; Paciello, A.; Scarascia Mugnozza, G.

    2011-06-01

    The basin-like setting of stiff bedrock combined with pre-existing landslide masses can contribute to seismic amplifications in a wide frequency range (0-10 Hz) and induce a self-excitation process responsible for earthquake-triggered landsliding. Here, the self-excitation process is proposed to justify the far-field seismic trigger of the Cerda landslide (Sicily, Italy) which was reactivated by the 6th September 2002 Palermo earthquake ( M s = 5.4), about 50 km far from the epicentre. The landslide caused damage to farm houses, roads and aqueducts, close to the village of Cerda, and involved about 40 × 106 m3 of clay shales; the first ground cracks due to the landslide movement formed about 30 min after the main shock. A stress-strain dynamic numerical modelling, performed by FDM code FLAC 5.0, supports the notion that the combination of local geological setting and earthquake frequency content played a fundamental role in the landslide reactivation. Since accelerometric records of the triggering event are not available, dynamic equivalent inputs have been used for the numerical modelling. These inputs can be regarded as representative for the local ground shaking, having a PGA value up to 0.2 m/s2, which is the maximum expected in 475 years, according to the Italian seismic hazard maps. A 2D numerical modelling of the seismic wave propagation in the Cerda landslide area was also performed; it pointed out amplification effects due to both the structural setting of the stiff bedrock (at about 1 Hz) and the pre-existing landslide mass (in the range 3-6 Hz). The frequency peaks of the resulting amplification functions ( A( f)) fit well the H/ V spectral ratios from ambient noise and the H/ H spectral ratios to a reference station from earthquake records, obtained by in situ velocimetric measurements. Moreover, the Fourier spectra of earthquake accelerometric records, whose source and magnitude are consistent with the triggering event, show a main peak at about 1 Hz

  17. Impact of pH on hydrogen oxidizing redox processes in aquifers due to gas intrusions

    Science.gov (United States)

    Metzgen, Adrian; Berta, Marton; Dethlefsen, Frank; Ebert, Markus; Dahmke, Andreas

    2017-04-01

    Hydrogen production from excess energy and its storage can help increasing the efficiency of solar and wind in the energy mix. Therefore, hydrogen needs large-scale intermediate storage independent of the intended later use as hydrogen gas or as reactant to produce methane in the Sabatier process. A possible storage solution is using the geological subsurface such as caverns built in salt deposits or aquifers that are not used for drinking water production. However, underground storage of hydrogen gas potentially leads to accidental gas leakages into near-surface potable aquifers triggering subsequent geochemical processes. These leakages pose potential risks that are currently not sufficiently understood. To close this gap in knowledge, a high-pressure laboratory column system was used to simulate a hydrogen gas intrusion into a shallow aquifer. Water and sediment were gained from a sandy Pleistocene aquifer near Neumünster, Germany. In the first stage of the experiment, 100% hydrogen gas was used to simulate dissolved hydrogen concentrations between 800 and 4000 µM by varying pH2 between 2 and 15 bars. pH values rose to between 7.9 and 10.4, partly due to stripping CO2 from the groundwater used during H2 gas addition. In a second stage, the pH was regulated in a range of 6.7 to 7.9 by using a gas mixture of 99% H2 and 1% CO2 at 5 bars of total gas pressure. Observed processes included hydrogen oxidation, sulfate reduction, acetogenesis, formate production, and methanogenesis, which were independent of the hydrogen concentration. Hydrogen oxidation and sulfate reduction showed zeroth order reaction rates and rate constants (106 to 412 µM/h and 12 to 33 µM/h, respectively) in the pH range between 8 and 10. At pH levels between 7 and 8, both reactions started out faster near the column's inflow but then seemed limited towards the columns outflow, suggesting the dependence of sulfate reduction on the pH-value. Acetogenesis dominated the pH range between 8 and 10

  18. SILTATION AND EROSION PROCESSES ON A TRIBUTARY OF LAKE ITAIPU DUE A DAM RESERVOIR

    Directory of Open Access Journals (Sweden)

    Cristiano Poleto

    2012-12-01

    creating an imbalance between the small amount of sediment transported after the hydroelectric and flow transport capacity. There are two cases occurring in a dam: 1 the dam upstream has a reduction of velocity and it start a process of sedimentation that will accelerate its siltation and reducing its useful life, 2 dam downstream has water velocity again and then initiate erosion process due the lack of sediments in the liquid mass. It can be concluded that changes of use and occupation of land in the watershed generate increased occurrence of peak flow and sediment transport, but the inadequate management of the area (with removal of riparian vegetation and lack of energy sinks in outputs of drainage systems potentiates the increasing the instability of water bodies morphology. In case of presence of reservoirs, the alterations are worst because they create siltation and erosion process at the same river.

  19. In vivo measurements of the T1 relaxation processes in the bone marrow in patients with myelodysplastic syndrome. A magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, K.E.; Nielsen, H.; Thomsen, C.; Soerensen, P.G.; Karle, H.; Christoffersen, P.; Henriksen, O. (Hvidovre Hospital, Copenhagen (Denmark). Dept. of Magnetic Resonance; Hvidovre Hospital, Copenhagen (Denmark). Dept. of Hematology; Hvidovre Hospital, Copenhagen (Denmark). Dept. of Pathology)

    Nine patients with myelodysplastic syndrome (MDS) were examined with magnetic resonance imaging and in vivo T1 relaxation time measurements of the vertebral bone marrow in a 1.5 tesla whole body scanner. Two patients underwent transformation to acute myeloid leukemia and were evaluated at follow-up examinations. At the time of diagnosis the T1 relaxation times of the vertebral bone marrow were significantly prolonged compared with normal values. The T1 relaxation times of the vertebral bone marrow in patients with MDS showed significantly lower values compared with patients with acute leukemia and did not differ from patients with polycythemia vera. (orig.).

  20. Multi-Objective Flexible Flow Shop Scheduling Problem Considering Variable Processing Time due to Renewable Energy

    Directory of Open Access Journals (Sweden)

    Xiuli Wu

    2018-03-01

    Full Text Available Renewable energy is an alternative to non-renewable energy to reduce the carbon footprint of manufacturing systems. Finding out how to make an alternative energy-efficient scheduling solution when renewable and non-renewable energy drives production is of great importance. In this paper, a multi-objective flexible flow shop scheduling problem that considers variable processing time due to renewable energy (MFFSP-VPTRE is studied. First, the optimization model of the MFFSP-VPTRE is formulated considering the periodicity of renewable energy and the limitations of energy storage capacity. Then, a hybrid non-dominated sorting genetic algorithm with variable local search (HNSGA-II is proposed to solve the MFFSP-VPTRE. An operation and machine-based encoding method is employed. A low-carbon scheduling algorithm is presented. Besides the crossover and mutation, a variable local search is used to improve the offspring’s Pareto set. The offspring and the parents are combined and those that dominate more are selected to continue evolving. Finally, two groups of experiments are carried out. The results show that the low-carbon scheduling algorithm can effectively reduce the carbon footprint under the premise of makespan optimization and the HNSGA-II outperforms the traditional NSGA-II and can solve the MFFSP-VPTRE effectively and efficiently.

  1. F-center mechanism of long-term relaxation in lead zirconate-titanate-based piezoelectric ceramics. 1. After-heating relaxation

    Directory of Open Access Journals (Sweden)

    V. M. Ishchuk

    2015-12-01

    The oxygen vacancies-based model for description of the long-time relaxation processes is suggested. The model takes into account oxygen vacancies on the sample’s surface ends, their conversion into F+- and F0-centers under external effects (due to the liberation of the pyroelectric charge and subsequent relaxation of these centers into the simple oxygen vacancies after the actions termination. The initial sample’s state is electroneutrality one. F-center formation leads to the violation of the original sample’s electroneutrality, and generates DC electric field into the sample. Relaxation of F-centers is accompanied by decreasing of electric field, induced by them, and dielectric constant relaxation as consequent effect.

  2. Fundamentals of ionic conductivity relaxation gained from study of procaine hydrochloride and procainamide hydrochloride at ambient and elevated pressure.

    Science.gov (United States)

    Wojnarowska, Z; Swiety-Pospiech, A; Grzybowska, K; Hawelek, L; Paluch, M; Ngai, K L

    2012-04-28

    The pharmaceuticals, procaine hydrochloride and procainamide hydrochloride, are glass-forming as well as ionically conducting materials. We have made dielectric measurements at ambient and elevated pressures to characterize the dynamics of the ion conductivity relaxation in these pharmaceuticals, and calorimetric measurements for the structural relaxation. Perhaps due to their special chemical and physical structures, novel features are found in the ionic conductivity relaxation of these pharmaceuticals. Data of conductivity relaxation in most ionic conductors when represented by the electric loss modulus usually show a single resolved peak in the electric modulus loss M(")(f) spectra. However, in procaine hydrochloride and procainamide hydrochloride we find in addition another resolved loss peak at higher frequencies over a temperature range spanning across T(g). The situation is analogous to many non-ionic glass-formers showing the presence of the structural α-relaxation together with the Johari-Goldstein (JG) β-relaxation. Naturally the analogy leads us to name the slower and faster processes resolved in procaine hydrochloride and procainamide hydrochloride as the primary α-conductivity relaxation and the secondary β-conductivity relaxation, respectively. The analogy of the β-conductivity relaxation in procaine HCl and procainamide HCl with JG β-relaxation in non-ionic glass-formers goes further by the finding that the β-conductivity is strongly related to the α-conductivity relaxation at temperatures above and below T(g). At elevated pressure but compensated by raising temperature to maintain α-conductivity relaxation time constant, the data show invariance of the ratio between the β- and the α-conductivity relaxation times to changes of thermodynamic condition. This property indicates that the β-conductivity relaxation has fundamental importance and is indispensable as the precursor of the α-conductivity relaxation, analogous to the relation found

  3. On the Internal Structure of Mobile Barchan Sand Dunes due to Granular Processes

    Science.gov (United States)

    Vriend, N. M.; Arran, M.; Louge, M. Y.; Hay, A. G.; Valance, A.

    2017-12-01

    In this work, we visualize the internal structure of mobile barchan desert dunes at the avalanche scale. We reveal an intriguing history of dune building using a novel combination of local sand sampling and advanced geophysical techniques resulting in high resolution measurements of individual avalanche events. Due to progressive rebuilding, granular avalanching, erosional and depositional processes, these marching barchan dunes are reworked every few years and a characteristic zebra-pattern (figure 1a), orientated parallel to the slipface at the angle of repose, appears at regular intervals. We present scientific data on the structure obtained from several mobile barchan dunes of different sizes during recent desert field campaigns (2014, 2015, 2017) in a mobile barchan dune field in Qatar (25.01°N, 51.34°E in the AlWakrah municipality). The site has been equipped with a weather station and has been regularly visited by a multidisciplinary research team in recent years (e.g. [1]). By applying high-frequency (1200 MHz) ground penetrating radar (GPR) transects across the midline (figure 1b) we map the continuous evolution of this cross-bedding at high resolution deep within the dune. The GPR reveals a slope reduction of the slipface near the base of the dune; evidence of irregular wind reversals; and the presence of a harder aeolian cap around the crest and extending to the brink. The data is supplemented with granulometry from layers stabilized by dyed water injection and uncovered by excavating vertical walls perpendicular to old buried avalanches. We attribute visible differences in water penetration between adjacent layers to fine particle segregation processes in granular avalanches. This work was made possible by the support of NPRP grant 6-059-2-023 from the Qatar National Research Fund to MYL and AGH, and a Royal Society Dorothy Hodgkin Research Fellowship to NMV. We thank Jean-Luc Métayer for performing detailed particle size distribution measurements

  4. Relaxation processes in rotational motion

    International Nuclear Information System (INIS)

    Broglia, R.A.

    1986-01-01

    At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

  5. Relaxation creep model of impending earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Morgounov, V. A. [Russian Academy of Sciences, Institute of Physics of the Earth, Moscow (Russian Federation)

    2001-04-01

    The alternative view of the current status and perspective of seismic prediction studies is discussed. In the problem of the ascertainment of the uncertainty relation Cognoscibility-Unpredictability of Earthquakes, priorities of works on short-term earthquake prediction are defined due to the advantage that the final stage of nucleation of earthquake is characterized by a substantial activation of the process while its strain rate increases by the orders of magnitude and considerably increased signal-to-noise ratio. Based on the creep phenomenon under stress relaxation conditions, a model is proposed to explain different images of precursors of impending tectonic earthquakes. The onset of tertiary creep appears to correspond to the onset of instability and inevitably fails unless it unloaded. At this stage, the process acquires the self-regulating character to the greatest extent the property of irreversibility, one of the important components of prediction reliability. Data in situ suggest a principal possibility to diagnose the process of preparation by ground measurements of acoustic and electromagnetic emission in the rocks under constant strain in the condition of self-relaxed stress until the moment of fracture are discussed in context. It was obtained that electromagnetic emission precedes but does not accompany the phase of macrocrak development.

  6. Relaxation characteristics of hastelloy X

    International Nuclear Information System (INIS)

    Suzuki, Kazuhiko

    1980-02-01

    Relaxation diagrams of Hastelloy X (relaxation curves, relaxation design diagrams, etc.) were generated from the creep constitutive equation of Hastelloy X, using inelastic stress analysis code TEPICC-J. These data are in good agreement with experimental relaxation data of ORNL-5479. Three typical inelastic stress analyses were performed for various relaxation behaviors of the high-temperature structures. An attempt was also made to predict these relaxation behaviors by the relaxation curves. (author)

  7. TEACHING NEUROMUSCULAR RELAXATION.

    Science.gov (United States)

    NORRIS, JEANNE E.; STEINHAUS, ARTHUR H.

    THIS STUDY ATTEMPTED TO FIND OUT WHETHER (1) THE METHODS FOR ATTAINING NEUROMUSCULAR RELAXATION THAT HAVE PROVED FRUITFUL IN THE ONE-TO-ONE RELATIONSHIP OF THE CLINIC CAN BE SUCCESSFULLY ADAPTED TO THE TEACHER-CLASS RELATIONSHIP OF THE CLASSROOM AND GYMNASIUM, AND (2) NEUROMUSCULAR RELAXATION CAN BE TAUGHT SUCCESSFULLY BY AN APPROPRIATELY TRAINED…

  8. Relaxation of Anisotropic Glasses

    DEFF Research Database (Denmark)

    Deubener, Joachim; Martin, Birgit; Wondraczek, Lothar

    2004-01-01

    . When the load was removed at room temperature a permanent optical anisotropy (birefringence) was observed only perpendicular to cylinder axis and the pressure direction indicating complete elimination of thermal stresses. Relaxation of structural anisotropy was studied from reheating experiments using...... the energy release, thermo-mechanical and optical relaxation behaviour are drawn....

  9. Relaxation techniques for stress

    Science.gov (United States)

    ... raise your heart rate. This is called the stress response. Relaxation techniques can help your body relax and lower your blood pressure ... also many other types of breathing techniques you can learn. In many cases, you do not need much ... including those that cause stress. Meditation has been practiced for thousands of years, ...

  10. Relationship between Structural and Stress Relaxation in a Block-Copolymer Melt

    International Nuclear Information System (INIS)

    Patel, Amish J.; Narayanan, Suresh; Sandy, Alec; Mochrie, Simon G. J.; Garetz, Bruce A.; Watanabe, Hiroshi; Balsara, Nitash P.

    2006-01-01

    The relationship between structural relaxation on molecular length scales and macroscopic stress relaxation was explored in a disordered block-copolymer melt. Experiments show that the structural relaxation time, measured by x-ray photon correlation spectroscopy is larger than the terminal stress relaxation time, measured by rheology, by factors as large as 100. We demonstrate that the structural relaxation data are dominated by the diffusion of intact micelles while the stress relaxation data are dominated by contributions due to disordered concentration fluctuations

  11. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    Energy Technology Data Exchange (ETDEWEB)

    Wiesenfeld, J.M.

    1977-12-01

    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 ..mu..s, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N/sub 2/ and O/sub 2/ matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data.

  12. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    International Nuclear Information System (INIS)

    Wiesenfeld, J.M.

    1977-12-01

    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 μs, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N 2 and O 2 matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data

  13. Magnon interaction and relaxation in yttrium iron garnet

    International Nuclear Information System (INIS)

    Mukimov, K.M.; Jumaev, M.R.; Kenjaev, Z.M.

    2007-01-01

    Full text: Magnon interaction and relaxation are the fundamental characteristics describing the response of any system to an external AC field. Almost all experiments aimed at magnon excitation have been carried out in the microwave frequency range where only magnons with energies 0.1 - 5 K can be excited. Nevertheless, all magnons with energy lower or order of the temperature are involved in the processes of low energy magnon relaxation. The present study deals with the interactions of magnons in YIG in thermodynamic equilibrium at temperatures up to 300 K. We consider the exchange and magnetic - dipole terms in the YIG Hamiltonian and a term due to the local uniaxial crystallographic anisotropy, find the corresponding amplitudes of three - and four - magnon process, and calculate the relaxation rate and the correction to the ferromagnon frequency to the first order in the interaction. This correction is positive, in contrast to the case of ferromagnets, and it is proportional to at temperatures up to, in agreement with experiment. The exchange - relaxation rate of the magnons is found as a function of the wave vector and temperature. In the region this rate agrees with the familiar expression for ferromagnets. At higher temperatures, at which the main contribution to the exchange damping is from the magnons of the linear part of the spectrum, the temperature dependence of the damping becomes stronger. (authors)

  14. High signal to noise ratio THz spectroscopy with ASOPS and signal processing schemes for mapping and controlling molecular and bulk relaxation processes

    International Nuclear Information System (INIS)

    Hadjiloucas, S; Walker, G C; Bowen, J W; Becerra, V M; Zafiropoulos, A; Galvao, R K H

    2009-01-01

    Asynchronous Optical Sampling has the potential to improve signal to noise ratio in THz transient sperctrometry. The design of an inexpensive control scheme for synchronising two femtosecond pulse frequency comb generators at an offset frequency of 20 kHz is discussed. The suitability of a range of signal processing schemes adopted from the Systems Identification and Control Theory community for further processing recorded THz transients in the time and frequency domain are outlined. Finally, possibilities for femtosecond pulse shaping using genetic algorithms are mentioned.

  15. High signal to noise ratio THz spectroscopy with ASOPS and signal processing schemes for mapping and controlling molecular and bulk relaxation processes

    Energy Technology Data Exchange (ETDEWEB)

    Hadjiloucas, S; Walker, G C; Bowen, J W; Becerra, V M [Cybernetics, School of Systems Engineering, University of Reading, RG6 6AY (United Kingdom); Zafiropoulos, A [Biosystems Engineering Department, School of Agricultural Technology, Technological Educational Institute of Larissa, 411 10, Larissa (Greece); Galvao, R K H, E-mail: s.hadjiloucas@reading.ac.u [Divisao de Engenharia Eletronica, Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, SP, 12228-900 Brazil (Brazil)

    2009-08-01

    Asynchronous Optical Sampling has the potential to improve signal to noise ratio in THz transient sperctrometry. The design of an inexpensive control scheme for synchronising two femtosecond pulse frequency comb generators at an offset frequency of 20 kHz is discussed. The suitability of a range of signal processing schemes adopted from the Systems Identification and Control Theory community for further processing recorded THz transients in the time and frequency domain are outlined. Finally, possibilities for femtosecond pulse shaping using genetic algorithms are mentioned.

  16. Kramers degeneracy and relaxation in vanadium, niobium and tantalum clusters

    Science.gov (United States)

    Diaz-Bachs, A.; Katsnelson, M. I.; Kirilyuk, A.

    2018-04-01

    In this work we use magnetic deflection of V, Nb, and Ta atomic clusters to measure their magnetic moments. While only a few of the clusters show weak magnetism, all odd-numbered clusters deflect due to the presence of a single unpaired electron. Surprisingly, for the majority of V and Nb clusters an atomic-like behavior is found, which is a direct indication of the absence of spin–lattice interaction. This is in agreement with Kramers degeneracy theorem for systems with a half-integer spin. This purely quantum phenomenon is surprisingly observed for large systems of more than 20 atoms, and also indicates various quantum relaxation processes, via Raman two-phonon and Orbach high-spin mechanisms. In heavier, Ta clusters, the relaxation is always present, probably due to larger masses and thus lower phonon energies, as well as increased spin–orbit coupling.

  17. Spin relaxation in nanowires by hyperfine coupling

    International Nuclear Information System (INIS)

    Echeverria-Arrondo, C.; Sherman, E.Ya.

    2012-01-01

    Hyperfine interactions establish limits on spin dynamics and relaxation rates in ensembles of semiconductor quantum dots. It is the confinement of electrons which determines nonzero hyperfine coupling and leads to the spin relaxation. As a result, in nanowires one would expect the vanishing of this effect due to extended electron states. However, even for relatively clean wires, disorder plays a crucial role and makes electron localization sufficient to cause spin relaxation on the time scale of the order of 10 ns. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Collisional relaxation of electron tail distribution

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru; Okamoto, Masao.

    1985-05-01

    Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

  19. Slow relaxation in weakly open rational polygons.

    Science.gov (United States)

    Kokshenev, Valery B; Vicentini, Eduardo

    2003-07-01

    The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.

  20. Stress relaxation under cyclic electron irradiation

    International Nuclear Information System (INIS)

    Bystrov, L.N.; Reznitskij, M.E.

    1990-01-01

    The kinetics of deformation process in a relaxating sample under 2 MeV electron cyclic irradiation was studied experimentally. The Al-Mg alloys with controllable and different (in dislocation density precipitate presence and their character) structure were used in experiments. It was established that after the beam was switched on the deformation rate increased sharply and then, during prolonged irradiation, in a gradual manner. After the switching-off the relaxation rate decreases by jumps up to values close to extrapolated rates of pre-radiation relaxation. The exhibition of these effects with radiation switching-off and switchin-on is dependent on the initial rate of thermal relaxation, the test temperature, the preliminary cold deformation and the dominating deformation dislocation mechanism. The preliminary cold deformation and test temperature elevation slightly decrease the effect of instantaneous relaxation acceleration with the irradiation switch-on. 17 refs., 5 figs

  1. Vibrational relaxation in liquids: Comparisons between gas phase and liquid phase theories

    International Nuclear Information System (INIS)

    Russell, D.J.

    1990-12-01

    The vibrational relaxation of iodine in liquid xenon was studied to understand what processes are important in determining the density dependence of the vibrational relaxation. This examination will be accomplished by taking simple models and comparing the results to both experimental outcomes and the predictions of molecular dynamics simulations. The vibration relaxation of iodine is extremely sensitive to the iodine potential. The anharmonicity of iodine causes vibrational relaxation to be much faster at the top of the iodine well compared to the vibrational relaxation at the bottom. A number of models are used in order to test the ability of the Isolated Binary Collision theory's ability to predict the density dependence of the vibrational relaxation of iodine in liquid xenon. The models tested vary from the simplest incorporating only the fact that the solvent occupies volume to models that incorporate the short range structure of the liquid in the radial distribution function. None of the models tested do a good job of predicting the actual relaxation rate for a given density. This may be due to a possible error in the choice of potentials to model the system

  2. Heterogeneity of glucagonomas due to differential processing of proglucagon-derived peptides

    DEFF Research Database (Denmark)

    Challis, Benjamin G; Albrechtsen, Nicolai J Wewer; Bansiya, Vishakha

    2015-01-01

    activities including critical roles in glucose and amino acid metabolism, energy homeostasis and gastrointestinal physiology.The clinical manifestations of proglucagon-expressing tumours may exhibit marked phenotypic variation due to the biochemical heterogeneity of their secreted peptide repertoire...... the rash. Case 2, a 48-year-old male presented with diabetes mellitus, diarrhoea, weight loss, nausea, vomiting and perineal rash due to a grade 1 metastatic pNET and hyperglucagonaemia. In both cases, plasma levels of all measured PGDPs were elevated and attenuated following SSA therapy. In case 1...

  3. Spin relaxation rates in quantum dots: Role of the phonon modulated spin orbit interaction

    Science.gov (United States)

    Alcalde, A. M.; Romano, C. L.; Marques, G. E.

    2008-11-01

    We calculate the spin relaxation rates in InAs and GaAs parabolic quantum dots due to the interaction of spin carriers with acoustical phonons. We consider a spin relaxation mechanism completely intrinsic to the system, since it is based on the modulation of the spin-orbit interaction by the acoustic phonon potential, which is independent of any structural properties of the confinement potential. The electron-phonon deformation potential and the piezoelectric interaction are described by the Pavlov-Firsov spin-phonon Hamiltonian. Our results demonstrate that, for narrow-gap semiconductors, the deformation potential interaction becomes dominant. This behavior is not observed for wide or intermediate gap semiconductors, where the piezoelectric coupling, in general, governs the relaxation processes. We also demonstrate that the spin relaxation rates are particularly sensitive to values of the Landé g-factor, which depend strongly on the spatial shape of the confinement.

  4. Dielectric relaxation in Li2SO4 in the intermedia-temperature regime

    Science.gov (United States)

    Diosa, J. E.; Vargas, R. A.; Fernández, M. E.; Albinsson, I.; Mellander, B.-E.

    2005-08-01

    The dielectric permittivity of polycrystalline Li2SO4 was measured from 5 Hz to 13 MHz and over the temperature range 235-460 °C. The corrected imaginary part of permittivity, , and its real part vs. frequency clearly show a new dielectric relaxation around fmax = 2 × 104 Hz at T = 256 °C, which shifts to higher frequencies (1 MHz) as the temperatures increases. The relaxation frequency (calculated from the peak position of ) vs. reciprocal T shows an activated relaxation process with activation energy Ea= 0.9 eV, which is very close to that derived from the dc conductivity, E (0.87 eV). We suggest that this dielectric relaxation could be due to the Li+ jump and SO4- reorientation that cause distortion and change of the local lattice polarizability inducing dipoles like LiSO4-.

  5. Nuclear spin phonon relaxation by Raman process in Na{sub 3}H(SO{sub 4}){sub 2} single crystals with the electric-quadrupole-type interaction using {sup 1}H and {sup 23}Na NMR

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ae Ran [Department of Science Education, Jeonju University, Jeonju 560-759, Chonbuk (Korea, Republic of)], E-mail: aeranlim@hanmail.net; Shin, Chang Woo [Solid State Analysis Team, Korea Basic Science Institute, Daegu 702-701 (Korea, Republic of)

    2008-11-30

    Successive phase transitions in a Na{sub 3}H(SO{sub 4}){sub 2} single crystal were found at 296, 513, and 533 K. To investigate the mechanism of the phase transition at 296 K, the {sup 1}H and {sup 23}Na spin-lattice relaxation time and the spin-spin relaxation time of Na{sub 3}H(SO{sub 4}){sub 2} were measured near the phase transition temperature using a FT NMR spectrometer. The spin-lattice relaxation time, T{sub 1}, for {sup 1}H in Na{sub 3}H(SO{sub 4}){sub 2} crystals exhibits a minimum below T{sub C1} (=296 K) indicating the presence of distinct molecular motion governed by the Bloembergen-Purcell-Pound (BPP) theory. Although the results for the {sup 1}H and {sup 23}Na relaxation times provide no evidence of the phase transition at T{sub C1}, the separation of the {sup 23}Na resonance lines changes abruptly at T{sub C1}. The phase transition at 296 K produces a change in the separation of the Na resonance line that is associated with a change in the atomic positions in the vicinity of the Na ions. Also, the nuclear spin-lattice relaxation process in Na{sub 3}H(SO{sub 4}){sub 2} crystals with the electric-quadrupole-type interaction proceed via Raman process. These results are compared with those obtained for other M{sub 3}H(SO{sub 4}){sub 2} (M=K, Rb, and Cs) crystals, which have similar hydrogen-bonded structures.

  6. Equilibrium positions due to different cooling processes in superconducting levitation systems

    International Nuclear Information System (INIS)

    Navau, C; Sanchez, A; Pardo, E; Chen, D-X

    2004-01-01

    The equilibrium position of a superconducting levitation device is determined not only by the geometry and electromagnetic properties of its components, but also by the cooling process of the superconductor. In this work we study the dependence of the equilibrium positions upon the cooling process by introducing diagrams of a new kind which display the different possibilities for a given levitation system. Using the critical state model and the principle of magnetic energy, we calculate different diagrams of this type for the case of a cylindrically symmetric permanent magnet-superconductor system. The results allow us to find out, for a given levitation system, which cooling process improves the capabilities of the system

  7. The relaxation time approximation

    International Nuclear Information System (INIS)

    Gairola, R.P.; Indu, B.D.

    1991-01-01

    A plausible approximation has been made to estimate the relaxation time from a knowledge of the transition probability of phonons from one state (r vector, q vector) to other state (r' vector, q' vector), as a result of collision. The relaxation time, thus obtained, shows a strong dependence on temperature and weak dependence on the wave vector. In view of this dependence, relaxation time has been expressed in terms of a temperature Taylor's series in the first Brillouin zone. Consequently, a simple model for estimating the thermal conductivity is suggested. the calculations become much easier than the Callaway model. (author). 14 refs

  8. In vivo measurements of the T1 relaxation processes in the bone marrow in patients with myelodysplastic syndrome. A magnetic resonance imaging study

    DEFF Research Database (Denmark)

    Jensen, K E; Nielsen, H; Thomsen, C

    1989-01-01

    Nine patients with myelodysplastic syndrome (MDS) were examined with magnetic resonance imaging and in vivo T1 relaxation time measurements of the vertebral bone marrow in a 1.5 tesla whole body scanner. Two patients underwent transformation to acute myeloid leukemia and were evaluated at follow-...... not differ from patients with polycythemia vera....

  9. Changes in T1 relaxation processes in the bone marrow following treatment in children with acute lymphoblastic leukemia. A magnetic resonance imaging study

    DEFF Research Database (Denmark)

    Jensen, K E; Thomsen, C; Henriksen, O

    1990-01-01

    data from bone marrow biopsies obtained in close association to the MR examinations. Ten age matched children were examined as a control group. A 1.5 Tesla whole body scanner was used for the measurements. The pretreatment T1 relaxation times of the bone marrow were significantly prolonged, compared...

  10. Evaluation of consequence due to higher hydrazine content in partitioning stream of PUREX process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, K. Suresh [Bhabha Atomic Research Centre, Mumbai (India). Special Nuclear Recycle Facility

    2016-07-01

    Hydrazine nitrate is being used as a stabilizer for U(IV) as well as Pu(III) during partitioning of Pu in PUREX process by scavenging the nitrous acid present along with nitric acid. As hydrazine hydrate as well as its salts have been successfully used for scrubbing of degradation products of TBP to aqueous phase, experiments were conducted to evaluate the consequence of hydrazine content during Pu partitioning. It was observed that higher amount of hydrazine nitrate along with uranous nitrate in the partitioning stream of PUREX process leads to build up of DBP in aqueous phase and resulted in precipitation of Pu.

  11. Relaxation model of radiation-induced conductivity in polymers

    Science.gov (United States)

    Zhutayeva, Yu. R.; Khatipov, S. A.

    1999-05-01

    The paper suggests a relaxation model of radiation-induced conductivity (RIC) in polymers. According to the model, the transfer of charges generated in the polymer volume by ionizing radiation takes place with the participation of molecular relaxation processes. The mechanism of electron transport consists in the transfer of the charge directly between traps when they draw close to one another due to the rotation of macromolecule segments. The numerical solutions of the corresponding kinetic equations for different distribution functions Q( τ) of the times of molecular relaxation and for different functions of the probability P( τ, τ') of charge transfer in the `overlapping' regions of the diffusion spheres of the segments are analyzed. The relaxation model provides an explanation of the non-Arrhenius behavior of the RIC temperature dependence, the power dependence of RIC on the dose rate with a power index in the interval 0.5-1.0, the appearance of maxima in the curves of the RIC temporal dependence and their irreversible character in the region of large dose rates (more than 1 Gy/s). The model can be used for interpreting polymer RIC in conditions of kinetic mobility of macromolecules.

  12. Estimation of the Past and Future Infrastructure Damage Due the Permafrost Evolution Processes

    Science.gov (United States)

    Sergeev, D. O.; Chesnokova, I. V.; Morozova, A. V.

    2015-12-01

    The geocryological processes such as thermokarst, frost heaving and fracturing, icing, thermal erosion are the source of immediate danger for the structures. The economic losses during the construction procedures in the permafrost area are linked also with the other geological processes that have the specific character in cold regions. These processes are swamping, desertification, deflation, flooding, mudflows and landslides. Linear transport structures are most vulnerable component of regional and national economy. Because the high length the transport structures have to cross the landscapes with different permafrost conditions that have the different reaction to climate change. The climate warming is favorable for thermokarst and the frost heaving is linked with climate cooling. In result the structure falls in the circumstances that are not predicted in the construction project. Local engineering problems of structure exploitation lead to global risks of sustainable development of regions. Authors developed the database of geocryological damage cases for the last twelve years at the Russian territory. Spatial data have the attributive table that was filled by the published information from various permafrost conference proceedings. The preliminary GIS-analysis of gathered data showed the widespread territorial distribution of the cases of negative consequences of geocryological processes activity. The information about maximum effect from geocryological processes was validated by detailed field investigation along the railways in Yamal and Transbaicalia Regions. Authors expect the expanding of database by similar data from other sectors of Arctic. It is important for analyzing the regional, time and industrial tendencies of geocryological risk evolution. Obtained information could be used in insurance procedures and in information systems of decisions support in different management levels. The investigation was completed with financial support by Russian

  13. Due Process in Dual Process: Model-Recovery Simulations of Decision-Bound Strategy Analysis in Category Learning

    Science.gov (United States)

    Edmunds, Charlotte E. R.; Milton, Fraser; Wills, Andy J.

    2018-01-01

    Behavioral evidence for the COVIS dual-process model of category learning has been widely reported in over a hundred publications (Ashby & Valentin, 2016). It is generally accepted that the validity of such evidence depends on the accurate identification of individual participants' categorization strategies, a task that usually falls to…

  14. Nuclear magnetic resonance relaxation in multiple sclerosis

    DEFF Research Database (Denmark)

    Larsson, H B; Barker, G J; MacKay, A

    1998-01-01

    OBJECTIVES: The theory of relaxation processes and their measurements are described. An overview is presented of the literature on relaxation time measurements in the normal and the developing brain, in experimental diseases in animals, and in patients with multiple sclerosis. RESULTS...... AND CONCLUSION: Relaxation time measurements provide insight into development of multiple sclerosis plaques, especially the occurrence of oedema, demyelination, and gliosis. There is also evidence that normal appearing white matter in patients with multiple sclerosis is affected. What is now needed are fast...

  15. Anomalous scaling due to correlations: limit theorems and self-similar processes

    International Nuclear Information System (INIS)

    Stella, Attilio L; Baldovin, Fulvio

    2010-01-01

    We derive theorems which outline explicit mechanisms by which anomalous scaling for the probability density function of the sum of many correlated random variables asymptotically prevails. The results characterize general anomalous scaling forms, explain their universal character, and specify universality domains in the spaces of joint probability density functions of the summand variables. These density functions are assumed to be invariant under arbitrary permutations of their arguments. Examples from the theory of critical phenomena are discussed. The novel notion of stability implied by the limit theorems also allows us to define sequences of random variables whose sum satisfies anomalous scaling for any finite number of summands. If regarded as developing in time, the stochastic processes described by these variables are non-Markovian generalizations of Gaussian processes with uncorrelated increments, and provide, e.g., explicit realizations of a recently proposed model of index evolution in finance

  16. Maximum Lateness Scheduling on Two-Person Cooperative Games with Variable Processing Times and Common Due Date

    OpenAIRE

    Liu, Peng; Wang, Xiaoli

    2017-01-01

    A new maximum lateness scheduling model in which both cooperative games and variable processing times exist simultaneously is considered in this paper. The job variable processing time is described by an increasing or a decreasing function dependent on the position of a job in the sequence. Two persons have to cooperate in order to process a set of jobs. Each of them has a single machine and their processing cost is defined as the minimum value of maximum lateness. All jobs have a common due ...

  17. Vibrational relaxation dynamics of SD molecules in As2S3: Observation of an anomalous isotope effect

    International Nuclear Information System (INIS)

    Engholm, J.R.; Happek, U.; Rella, C.W.

    1995-01-01

    It is generally assumed that the vibrational relaxation of molecular impurities in crystals and glasses mainly depends on the order of the decay process, with lower order processes leading to more rapid relaxation (a behavior that is known under the term open-quotes gap-lawclose quotes). Here we present measurements that contradict this assumption. Using high intensity psec pulses of the Stanford FEL we measured the relaxation rate of the SD vibrational stretch mode (at a frequency of 1800 cm) by applying a pump-probe technique. We find relaxation rates on the order of 2x10 9 sec -1 , which are a factor of 2 lower than those found for the isotope molecule SH (at a frequency of about 2500 cm - 1 ) in the same host 1 . We recall that the relaxation of the SD vibrational stretch mode is controlled by a lower order process as compared to the SH molecule, which is due to the smaller number of host vibrational quanta to match the energy of the stretch mode; a fact we have confirmed experimentally by temperature dependent relaxation measurements. Thus our remits are in marked contrast to the so-called open-quotes Gap-Lawclose quotes and emphasize the importance of the molecule - host coupling in the relaxation dynamics

  18. Impact of residual by-products from tungsten film deposition on process integration due to nonuniformity of the tungsten film

    CERN Document Server

    Sidhwa, A; Gandy, T; Melosky, S; Brown, W; Ang, S; Naseem, H; Ulrich, R

    2002-01-01

    The effects of residual by products from a tungsten film deposition process and their impact on process integration due to the nonuniformity of the tungsten film were investigated in this work. The tungsten film deposition process involves three steps: nucleation, stabilization, and tungsten bulk fill. Six experiments were conducted in search for a solution to the problem. The resulting data suggest that excess nitrogen left in the chamber following the tungsten nucleation step, along with residual by products, causes a shift in the tungsten film uniformity during the tungsten bulk fill process. Data reveal that, due to the residual by products, an abnormal grain growth occurs causing a variation in the tungsten thickness across the wafer during the bulk fill step. Although several possible solutions were revealed by the experiments, potential integration problems limited the acceptable solutions to one. The solution chosen was the introduction of a 10 s pumpdown immediately following the nucleation step. Thi...

  19. Torque strength of an endplate welding due to process parameters using a fuel assembling welder

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae-Seo; Kim, Soo-Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    As fuel bundles in a PHWR core irradiated, inner pressure in the claddings of the fuel rods increases owing to the outer pressure and fission products of the nuclear fissions. Because of a leak possibility from a welding between a cladding and end plug, this welding part is connected with the safety of nuclear fuel rods. Endplug-cladding welding of nuclear fuel rods in a PHWR takes advantage of a resistance upset butt welding. The weldment between a cladding and endplug is to be sound to prevent a leakage of fission products from a cladding as a UO{sub 2} pellet is irradiated. Weld flash was made from a deformation due to a welding heat and increasing the pressure of the resistivity and resistance from a cladding and endplug. Weld line of a welding interface, microstructure of a weldment and a crystallographic structure change were sources of an iodine induced SCC in a reactor. The soundness of a weldment is important because a weld line connects the leakage of fission products from an operational reactor. In this study, welding specimens were fabricated by a resistance welding method using a bundle fuel welder to measure and analyze the torque of an endplug-endplate welding. The torque of a weldment between an endplug and endplate was measured and analyzed with the welding time. The weldability of a weldment between an endplug and endplate was investigated by a metallographic examination.

  20. Relaxation and hypnosis in pediatric dental patients.

    Science.gov (United States)

    Peretz, B

    1996-01-01

    Relaxation and hypnosis are methods which, may solve the problem of extreme dental anxiety, when all other methods, behavioral or pharmacological may not be used. A simple definition of hypnosis is suggestion and repetition. Suggestion is the process whereby an individual accepts a proposition put to him by another, without having the slightest logical reason for doing so. Relaxation is one method of inducing hypnosis. A case of using hypnosis on an 11-year-old boy is described.

  1. Regularities of intermediate adsorption complex relaxation

    International Nuclear Information System (INIS)

    Manukova, L.A.

    1982-01-01

    The experimental data, characterizing the regularities of intermediate adsorption complex relaxation in the polycrystalline Mo-N 2 system at 77 K are given. The method of molecular beam has been used in the investigation. The analytical expressions of change regularity in the relaxation process of full and specific rates - of transition from intermediate state into ''non-reversible'', of desorption into the gas phase and accumUlation of the particles in the intermediate state are obtained

  2. Limitations Of The Current State Space Modelling Approach In Multistage Machining Processes Due To Operation Variations

    Science.gov (United States)

    Abellán-Nebot, J. V.; Liu, J.; Romero, F.

    2009-11-01

    The State Space modelling approach has been recently proposed as an engineering-driven technique for part quality prediction in Multistage Machining Processes (MMP). Current State Space models incorporate fixture and datum variations in the multi-stage variation propagation, without explicitly considering common operation variations such as machine-tool thermal distortions, cutting-tool wear, cutting-tool deflections, etc. This paper shows the limitations of the current State Space model through an experimental case study where the effect of the spindle thermal expansion, cutting-tool flank wear and locator errors are introduced. The paper also discusses the extension of the current State Space model to include operation variations and its potential benefits.

  3. Clarifying Cutting and Sewing Processes with Due Windows Using an Effective Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Rong-Hwa Huang

    2013-01-01

    Full Text Available The cutting and sewing process is a traditional flow shop scheduling problem in the real world. This two-stage flexible flow shop is often commonly associated with manufacturing in the fashion and textiles industry. Many investigations have demonstrated that the ant colony optimization (ACO algorithm is effective and efficient for solving scheduling problems. This work applies a novel effective ant colony optimization (EACO algorithm to solve two-stage flexible flow shop scheduling problems and thereby minimize earliness, tardiness, and makespan. Computational results reveal that for both small and large problems, EACO is more effective and robust than both the particle swarm optimization (PSO algorithm and the ACO algorithm. Importantly, this work demonstrates that EACO can solve complex scheduling problems in an acceptable period of time.

  4. Physical quality characteristics of the microwave-dried breadfruit powders due to different processing conditions

    Science.gov (United States)

    Taruna, I.; Hakim, A. L.; Sutarsi

    2018-03-01

    Production of breadfruit powder has been an option to make easy its uses in various food processing. Accordingly, there is a need recently to apply advanced drying method, i.e. microwave drying, for improving quality since conventional methods produced highly variable product quality and required longer process. The present work was aimed to study the effect of microwave power and grinding time on physical quality of breadfruit powders. The experiment was done initially by drying breadfruit slices in a microwave dryer at power level of 420, 540, and 720 W and then grinding for 3, 5, and 7 min to get powdery product of less than 80 mesh. The physical quality of breadfruit powders were measured in terms of fineness modulus (FM), average particle size (D), whiteness (WI), total color difference (ΔE), water absorption (Wa), oil absorption (La), bulk density (ρb) and consistency gel (Gc). The results showed that physical quality of powders and its ranged-values included the FM (2.08-2.62), D (0.44-0.68 mm), WI (75.2-77.9), ΔE (7.4-10.5), Wa (5.5-6.2 ml/g), La (0.7-0.9 ml/g), ρb (0.62-0.70 g/cm3) and Gc (41.3-46.8 mm). The experiment revealed that variation of microwave power and grinding time affected significantly the quality of the breadfruit powders. However, microwave power was more dominant factor to affect quality of breadfruit powder in comparison to the grinding time.

  5. Enhancing Title Ix Due Process Standards in Campus Sexual Assault Adjudication: Considering the Roles of Distributive, Procedural, and Restorative Justice

    Science.gov (United States)

    Harper, Shannon; Maskaly, Jon; Kirkner, Anne; Lorenz, Katherine

    2017-01-01

    Title IX prohibits sex discrimination--including sexual assault--in higher education. The Department of Education Office for Civil Rights' 2011 "Dear Colleague Letter" outlines recommendations for campus sexual assault adjudication allowing a variety of procedures that fail to protect accused students' due process rights and victims'…

  6. Home-Schools and Interscholastic Sports: Denying Participation Violates United States Constitutional Due Process and Equal Protection Rights. Chalk Talk.

    Science.gov (United States)

    Webb, Derwin L.

    1997-01-01

    Participation in sports, in some instances, is considered a right which grants students the opportunity to be involved in extracurricular activities. Discusses the potential violation of home-schooled students' constitutional due process and equal protection rights and the pertinent laws regarding students and their ability to participate in…

  7. Single Machine Scheduling and Due Date Assignment with Past-Sequence-Dependent Setup Time and Position-Dependent Processing Time

    Directory of Open Access Journals (Sweden)

    Chuan-Li Zhao

    2014-01-01

    Full Text Available This paper considers single machine scheduling and due date assignment with setup time. The setup time is proportional to the length of the already processed jobs; that is, the setup time is past-sequence-dependent (p-s-d. It is assumed that a job's processing time depends on its position in a sequence. The objective functions include total earliness, the weighted number of tardy jobs, and the cost of due date assignment. We analyze these problems with two different due date assignment methods. We first consider the model with job-dependent position effects. For each case, by converting the problem to a series of assignment problems, we proved that the problems can be solved in On4 time. For the model with job-independent position effects, we proved that the problems can be solved in On3 time by providing a dynamic programming algorithm.

  8. Modeling deformation processes of salt caverns for gas storage due to fluctuating operation pressures

    Science.gov (United States)

    Böttcher, N.; Nagel, T.; Goerke, U.; Khaledi, K.; Lins, Y.; König, D.; Schanz, T.; Köhn, D.; Attia, S.; Rabbel, W.; Bauer, S.; Kolditz, O.

    2013-12-01

    In the course of the Energy Transition in Germany, the focus of the country's energy sources is shifting from fossil to renewable and sustainable energy carriers. Since renewable energy sources, such as wind and solar power, are subjected to annual, seasonal, and diurnal fluctuations, the development and extension of energy storage capacities is a priority in German R&D programs. Common methods of energy storage are the utilization of subsurface caverns as a reservoir for natural or artificial fuel gases, such as hydrogen, methane, or the storage of compressed air. The construction of caverns in salt rock is inexpensive in comparison to solid rock formations due to the possibility of solution mining. Another advantage of evaporite as a host material is the self-healing capacity of salt rock. Gas caverns are capable of short-term energy storage (hours to days), so the operating pressures inside the caverns are fluctuating periodically with a high number of cycles. This work investigates the influence of fluctuating operation pressures on the stability of the host rock of gas storage caverns utilizing numerical models. Therefore, we developed a coupled Thermo-Hydro-Mechanical (THM) model based on the finite element method utilizing the open-source software platform OpenGeoSys. Our simulations include the thermodynamic behaviour of the gas during the loading/ unloading of the cavern. This provides information on the transient pressure and temperature distribution on the cavern boundary to calculate the deformation of its geometry. Non-linear material models are used for the mechanical analysis, which describe the creep and self-healing behavior of the salt rock under fluctuating loading pressures. In order to identify the necessary material parameters, we perform experimental studies on the mechanical behaviour of salt rock under varying pressure and temperature conditions. Based on the numerical results, we further derive concepts for monitoring THM quantities in the

  9. Stress relaxation of bi-disperse polystyrene melts

    DEFF Research Database (Denmark)

    Hengeller, Ludovica; Huang, Qian; Dorokhin, Andriy

    2016-01-01

    We present start-up of uniaxial extension followed by stress relaxation experiments of a bi-disperse 50 % by weight blend of 95k and 545k molecular weight polystyrene. We also show, for comparison, stress relaxation measurements of the polystyrene melts with molecular weight 95k and 545k, which...... are the components of the bi-disperse melt. The measurements show three separated relaxation regimes: a fast regime, a transition regime, and a slow regime. In the fast regime, the orientation of the long chains is frozen and the stress relaxation is due to stretch relaxation of the short chains primarily....... Conversely in the slow regime, the long chains have retracted and undergo relaxation of orientation in fully relaxed short chains....

  10. Simulation of the charging process of the LISA test masses due to solar flares

    International Nuclear Information System (INIS)

    Vocca, H; Grimani, C; Amico, P; Bosi, L; Marchesoni, F; Punturo, M; Travasso, F; Barone, M; Stanga, R; Vetrano, F; Vicere, A

    2004-01-01

    Cosmic-ray and solar high energy particles penetrate the LISA experiment test masses. Consequently, an electric charge accumulates in the bodies of the masses, generating spurious Coulomb forces between the masses and the surrounding electrodes. This process increases the noise level of the experiment. We have estimated the amount of charge deposited per second on the LISA test masses by solar flares and primary cosmic-ray protons at solar minimum. The simulation has been carried out with the Fluka Monte Carlo program. A simplified geometry for the experiment has been considered. We have found a net charging rate of 37 ± 1 e + /s for primary protons at solar minimum between 0.1 and 1000 GeV/n. The amount of charge released by a medium-strong solar flare, like that of 16 February 1984, is 10 732 ± 30 e + /s in the energy range 0.1-10 GeV/n. This value increases or decreases by approximately one order of magnitude for strong (weak) solar flares

  11. Interfacial reaction between SiC and aluminium due to extrusion and heat treatment process

    International Nuclear Information System (INIS)

    Junaidah Jai; Fauzi Ismail; Samsiah Sulaiman; Patthi Hussain, Azmi Idris; Yoichi Murakoshi

    1999-01-01

    Chemical interaction between aluminium (Al) and silicon carbide (SiC) produces aluminium carbide (Al 4 C 3 ) which presents potential problems in the production and application of Al/SiC Metal Matrix Composit (MMC). The Al 4 C 3 formed can reduce material properties such as strength in the MMC. This research work investigates the interface reaction in Al 7075/SiC MMC made through hot extrusion process. Mixed Al 7075/SiC MMC powders were pressed at 300 degree C and extruded at 500 degree C, with a reduction ratio of 20:1. The extruded MMC was then heat-treated in air at various temperatures from 560 degree C, 600 degree C, 640 degree C, 700 degree C to 800 degree C in order to observe the interface reaction of the MMC materials. The heat-treated MMCs were then analyzed under the optical microscope, X-ray Diffraction (XRD) Spectroscope and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray (EDAZ) attachment to observe the interface reaction within the MMCs. This investigation confirms there was interface reaction between SiC and aluminium

  12. Characterization of ultrathin insulators in CMOS technology: Wearout and failure mechanisms due to processing and operation

    Science.gov (United States)

    Okandan, Murat

    In the CMOS technology the gate dielectric is the most critical layer, as its condition directly dictates the ultimate performance of the devices. In this thesis, the wear-out and failure mechanisms in ultra-thin (around 50A and lower) oxides are investigated. A new degradation phenomenon, quasi-breakdown (or soft-breakdown), and the annealing and stressing behavior of devices after quasi-breakdown are considered in detail. Devices that are in quasi-breakdown continue to operate as switches, but the gate leakage current is two orders of magnitude higher than the leakage in healthy devices and the stressing/annealing behavior of the devices are completely altered. This phenomenon is of utmost interest, since the reduction in SiO2 dielectric thickness has reached its physical limits, and the quasi-breakdown behavior is seen to dominate as a failure mode in this regime. The quasi-breakdown condition can be brought on by stresses during operation or processing. To further study this evolution through stresses and anneals, cyclic current-voltage (I-V) measurement has been further developed and utilized in this thesis. Cyclic IV is a simple and fast, two terminal measurement technique that looks at the transient current flowing in an MOS system during voltage sweeps from accumulation to inversion and back. During these sweeps, carrier trapping/detrapping, generation and recombination are observed. An experimental setup using a fast electrometer and analog to digital conversion (A/D) card and the software for control of the setup and data analysis were also developed to gain further insight into the detailed physics involved. Overall, the crucial aspects of wear-out and quasi-breakdown of ultrathin dielectrics, along with the methods for analyzing this evolution are presented in this thesis.

  13. Arresting relaxation in Pickering Emulsions

    Science.gov (United States)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  14. Progressive softening of brittle-ductile transition due to interplay between chemical and deformation processes

    Science.gov (United States)

    Jeřábek, Petr; Bukovská, Zita; Morales, Luiz F. G.

    2017-04-01

    The micro-scale shear zones (shear bands) in granitoids from the South Armorican Shear Zone reflect localization of deformation and progressive weakening in the conditions of brittle-ductile transition. We studied microstructures in the shear bands with the aim to establish their P-T conditions and to derive stress and strain rates for specific deformation mechanisms. The evolving microstructure within shear bands documents switches in deformation mechanisms related to positive feedbacks between deformation and chemical processes and imposes mechanical constraints on the evolution of the brittle-ductile transition in the continental transform fault domains. The metamorphic mineral assemblage present in the shear bands indicate their formation at 300-350 ˚ C and 100-400 MPa. Focusing on the early development of shear bands, we identified three stages of shear band evolution. The early stage I associated with initiation of shear bands occurs via formation of microcracks with possible yielding differential stress of up to 250 MPa (Diamond and Tarantola, 2015). Stage II is associated with subgrain rotation recrystallization and dislocation creep in quartz and coeval dissolution-precipitation creep of microcline. Recrystallized quartz grains in shear bands show continual increase in size, and decrease in stress and strain rates from 94 MPa to 17-26 MPa (Stipp and Tullis, 2003) and 3.8*10-12 s-1- 1.8*10-14 s-1 (Patterson and Luan, 1990) associated with deformation partitioning into weaker microcline layer and shear band widening. The quartz mechanical data allowed us to set some constrains for coeval dissolution-precipitation of microcline which at our estimated P-T conditions suggests creep at 17-26 MPa differential stress and 3.8*10-13 s-1 strain rate. Stage III is characterized by localized slip along interconnected white mica bands accommodated by dislocation creep at strain rate 3.8*10-12 s-1 and stress 9.36 MPa (Mares and Kronenberg, 1993). The studied example

  15. Nonmaxwell relaxation in disordered media: Physical mechanisms and fractional relaxation equations

    International Nuclear Information System (INIS)

    Arkhincheev, V.E.

    2004-12-01

    The problem of charge relaxation in disordered systems has been solved. It is shown, that due to the inhomogeneity of the medium the charge relaxation has a non-Maxwell character. The two physical mechanisms of a such behavior have been founded. The first one is connected with the 'fractality' of conducting ways. The second mechanism of nonexponential non-Maxwell behavior is connected with the frequency dispersion of effective conductivity of heterogeneous medium, initially consisting of conducting phases without dispersion. The new generalized relaxation equations in the form of fractional temporal integro-differential equations are deduced. (author)

  16. Relaxation strain measurements in cellular dislocation structures

    International Nuclear Information System (INIS)

    Tsai, C.Y.; Quesnel, D.J.

    1984-01-01

    The conventional picture of what happens during a stress relaxation usually involves imagining the response of a single dislocation to a steadily decreasing stress. The velocity of this dislocation decreases with decreasing stress in such a way that we can measure the stress dependence of the dislocation velocity. Analysis of the data from a different viewpoint enables us to calculate the apparent activation volume for the motion of the dislocation under the assumption of thermally activated glie. Conventional thinking about stress relaxation, however, does not consider the eventual fate of this dislocation. If the stress relaxes to a low enough level, it is clear that the dislocation must stop. This is consistent with the idea that we can determine the stress dependence of the dislocation velocity from relaxation data only for those cases where the dislocation's velocity is allowed to approach zero asymptotically, in short, for those cases where the dislocation never stops. This conflict poses a dilemma for the experimentalist. In real crystals, however, obstacles impede the dislocation's progress so that those dislocations which are stopped at a given stress will probably never resume motion under the influence of the steadily declining stress present during relaxation. Thus one could envision stress relaxation as a process of exhaustion of mobile dislocations, rather than a process of decreasing dislocation velocity. Clearly both points of view have merit and in reality both mechanisms contribute to the phenomena

  17. Relaxation of quadrupole orientation in an optically pumped alkali vapour

    Energy Technology Data Exchange (ETDEWEB)

    Bernabeu, E; Tornos, J

    1985-04-01

    The relaxation of quadrupole orientation (alignment) in an optically pumped alkali vapour is theoretically studied by taking into account the relaxation processes by alkali-buffer gas, alkali-alkali with spin exchange and alkali-cell wall (diffusion process) collisions. The relaxation transients of the quadrupole orientation are obtained by introducing a first-order weak-pumping approximation (intermediate pumping) less restrictive than the usually considered (zeroth order) one.

  18. Maximum Lateness Scheduling on Two-Person Cooperative Games with Variable Processing Times and Common Due Date

    Directory of Open Access Journals (Sweden)

    Peng Liu

    2017-01-01

    Full Text Available A new maximum lateness scheduling model in which both cooperative games and variable processing times exist simultaneously is considered in this paper. The job variable processing time is described by an increasing or a decreasing function dependent on the position of a job in the sequence. Two persons have to cooperate in order to process a set of jobs. Each of them has a single machine and their processing cost is defined as the minimum value of maximum lateness. All jobs have a common due date. The objective is to maximize the multiplication of their rational positive cooperative profits. A division of those jobs should be negotiated to yield a reasonable cooperative profit allocation scheme acceptable to them. We propose the sufficient and necessary conditions for the problems to have positive integer solution.

  19. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang; Liu, Taixiang; Liao, G J; Lubineau, Gilles

    2017-01-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  20. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang

    2017-09-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  1. Discipline and Due Process.

    Science.gov (United States)

    Collins, Mildred; Dowell, Mary L.

    1998-01-01

    Increasing numbers of parents do not accept a school's discipline policy and are refusing to permit their children to comply with disciplinary sanctions. According to the California Education Code, educators have the right to expect parents to accept disciplinary decisions made in compliance with required procedures. Parental defiance might worsen…

  2. Role of step stiffness and kinks in the relaxation of vicinal (001) with zigzag [110] steps

    Science.gov (United States)

    Mahjoub, B.; Hamouda, Ajmi BH.; Einstein, TL.

    2017-08-01

    We present a kinetic Monte Carlo study of the relaxation dynamics and steady state configurations of 〈110〉 steps on a vicinal (001) simple cubic surface. This system is interesting because 〈110〉 (fully kinked) steps have different elementary excitation energetics and favor step diffusion more than 〈100〉 (nominally straight) steps. In this study we show how this leads to different relaxation dynamics as well as to different steady state configurations, including that 2-bond breaking processes are rate determining for 〈110〉 steps in contrast to 3-bond breaking processes for 〈100〉-steps found in previous work [Surface Sci. 602, 3569 (2008)]. The analysis of the terrace-width distribution (TWD) shows a significant role of kink-generation-annihilation processes during the relaxation of steps: the kinetic of relaxation, toward the steady state, is much faster in the case of 〈110〉-zigzag steps, with a higher standard deviation of the TWD, in agreement with a decrease of step stiffness due to orientation. We conclude that smaller step stiffness leads inexorably to faster step dynamics towards the steady state. The step-edge anisotropy slows the relaxation of steps and increases the strength of step-step effective interactions.

  3. Hydrogen bond network relaxation in aqueous polyelectrolyte solutions: the effect of temperature

    International Nuclear Information System (INIS)

    Sarti, S; Bordi, F; Truzzolillo, D

    2012-01-01

    Dielectric spectroscopy data over the range 100 MHz-40 GHz allow for a reliable analysis of two of the major relaxation phenomena for polyelectrolytes (PE) in water. Within this range, the dielectric relaxation of pure water is dominated by a near-Debye process at ν = 18.5 GHz corresponding to a relaxation time of τ = 8.4 ps at 25 °C. This mode is commonly attributed to the cooperative relaxation specific to liquids forming a hydrogen bond network (HBN) and arising from long range H-bond-mediated dipole-dipole interactions. The presence of charged polymers in water partially modifies the dielectric characteristics of the orientational water molecule relaxation due to a change of the dielectric constant of water surrounding the charges on the polyion chain. We report experimental results on the effect of the presence of a standard flexible polyelectrolyte (sodium polyacrylate) on the HBN relaxation in water for different temperatures, showing that the HBN relaxation time does not change by increasing the polyelectrolyte density in water, even if relatively high concentrations are reached (0.02 monomol l -1 ≤ C ≤ 0.4 monomol l -1 ). We also find that the effect of PE addition on the HBN relaxation is not even a broadening of its distribution, rather a decrease of the spectral weight that goes beyond the pure volume fraction effect. This extra decrease is larger at low T and less evident at high T, supporting the idea that the correlation length of the water is less affected by the presence of charged flexible chains at high temperatures. (paper)

  4. Relaxed Binaural LCMV Beamforming

    NARCIS (Netherlands)

    Koutrouvelis, A.; Hendriks, R.C.; Heusdens, R.; Jensen, Jesper Rindom

    2017-01-01

    In this paper, we propose a new binaural beamforming technique, which can be seen as a relaxation of the linearly constrained minimum variance (LCMV) framework. The proposed method can achieve simultaneous noise reduction and exact binaural cue preservation of the target source, similar to the

  5. Sub-Shot-Noise Magnetometry with a Correlated Spin-Relaxation Dominated Alkali-Metal Vapor

    International Nuclear Information System (INIS)

    Kominis, I. K.

    2008-01-01

    Spin noise sets fundamental limits to the precision of measurements using spin-polarized atomic vapors, such as performed with sensitive atomic magnetometers. Spin squeezing offers the possibility to extend the measurement precision beyond the standard quantum limit of uncorrelated atoms. Contrary to current understanding, we show that, even in the presence of spin relaxation, spin squeezing can lead to a significant reduction of spin noise, and hence an increase in magnetometric sensitivity, for a long measurement time. This is the case when correlated spin relaxation due to binary alkali-atom collisions dominates independently acting decoherence processes, a situation realized in thermal high atom-density magnetometers and clocks

  6. Influence of predictive contamination to agricultural products due to dry and wet processes during an accidental release of radionuclides

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Jeong, Hyo Joon; Han, Moon Hee; Lee, Chang Woo

    2003-01-01

    The influence of predictive contamination to agricultural products due to the wet processes as well as dry processes from radioactive air concentration during a nuclear emergency is comprehensively analyzed. The previous dynamic food chain model DYNACON considering Korean agricultural and environmental conditions, in which the initial input parameter was radionuclide concentrations on the ground, is improved so as to evaluate radioactive contamination to agricultural products from either radioactive air concentrations or radionuclide concentrations on the ground. As for the results, wet deposition is a more dominant mechanism than dry deposition in contamination on the ground. While, the contamination levels of agricultural products are strongly dependent on radionuclide and precipitation when the deposition of radionuclides occurs. It means that the contamination levels of agricultural products are determined from which is the more dominant process between deposition on the ground and interception to agricultural plants

  7. Communication: Vibrational relaxation of CO(1Σ) in collision with Ar(1S) at temperatures relevant to the hypersonic flight regime.

    Science.gov (United States)

    Denis-Alpizar, Otoniel; Bemish, Raymond J; Meuwly, Markus

    2017-03-21

    Vibrational energy relaxation (VER) of diatomics following collisions with the surrounding medium is an important elementary process for modeling high-temperature gas flow. VER is characterized by two parameters: the vibrational relaxation time τ vib and the state relaxation rates. Here the vibrational relaxation of CO(ν=0←ν=1) in Ar is considered for validating a computational approach to determine the vibrational relaxation time parameter (pτ vib ) using an accurate, fully dimensional potential energy surface. For lower temperatures, comparison with experimental data shows very good agreement whereas at higher temperatures (up to 25 000 K), comparisons with an empirically modified model due to Park confirm its validity for CO in Ar. Additionally, the calculations provide insight into the importance of Δν>1 transitions that are ignored in typical applications of the Landau-Teller framework.

  8. Geometrical relaxation of excitations in one-dimensional conjugated polymers; Giichijigen kyoeki kobunshi reiki jotai no shusa kozo kanwa

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, M. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1995-12-15

    Large ultrafast optical nonlinearities in conjugated polymers have attracted much attention because of possible applications to nonlinear optical devices. One-dimensional systems such as conjugated polymers have localized excited states with geometrical relaxation. In this study, photoexcited states in polydiacetylene has been investigated by femtosecond Raman gain spectroscopy with 300-fs resolution. A new photoinduced Raman peak with lifetime of 1.5 ps has been observed at 1200cm{sup -1} for the first time. This peak indicates acetylene-like structure of the main chain relaxes to butatriene-like structure due to the formation of self-trapped exciting with the geometrical relaxation. The formation and decay kinetics of the Raman signals is consistent with the relaxation processes of exciting observed by femtosecond absorption spectroscopy. 8 refs., 5 figs.

  9. Influence of silver nanoparticles on relaxation processes and efficiency of dipole – dipole energy transfer between dye molecules in polymethylmethacrylate films

    Energy Technology Data Exchange (ETDEWEB)

    Bryukhanov, V V; Borkunov, R Yu; Tsarkov, M V [Immanuel Kant Baltic Federal University, Kaliningrad (Russian Federation); Konstantinova, E I; Slezhkin, V A [Kaliningrad State Technical University, Kaliningrad (Russian Federation)

    2015-10-31

    The fluorescence and phosphorescence of dyes in thin polymethylmethacrylate (PMMA) films in the presence of ablated silver nanoparticles has been investigated in a wide temperature range by methods of femtosecond and picosecond laser photoexcitation. The fluorescence and phosphorescence times, as well as spectral and kinetic characteristics of rhodamine 6G (R6G) molecules in PMMA films are measured in a temperature range of 80 – 330 K. The temperature quenching activation energy of the fluorescence of R6G molecules in the presence of ablated silver nanoparticles is found. The vibrational relaxation rate of R6G in PMMA films is estimated, the efficiency of the dipole – dipole electron energy transfer between R6G and brilliant green molecules (enhanced by plasmonic interaction with ablated silver nanoparticles) is analysed, and the constants of this energy transfer are determined. (nanophotonics)

  10. Influence of silver nanoparticles on relaxation processes and efficiency of dipole – dipole energy transfer between dye molecules in polymethylmethacrylate films

    International Nuclear Information System (INIS)

    Bryukhanov, V V; Borkunov, R Yu; Tsarkov, M V; Konstantinova, E I; Slezhkin, V A

    2015-01-01

    The fluorescence and phosphorescence of dyes in thin polymethylmethacrylate (PMMA) films in the presence of ablated silver nanoparticles has been investigated in a wide temperature range by methods of femtosecond and picosecond laser photoexcitation. The fluorescence and phosphorescence times, as well as spectral and kinetic characteristics of rhodamine 6G (R6G) molecules in PMMA films are measured in a temperature range of 80 – 330 K. The temperature quenching activation energy of the fluorescence of R6G molecules in the presence of ablated silver nanoparticles is found. The vibrational relaxation rate of R6G in PMMA films is estimated, the efficiency of the dipole – dipole electron energy transfer between R6G and brilliant green molecules (enhanced by plasmonic interaction with ablated silver nanoparticles) is analysed, and the constants of this energy transfer are determined. (nanophotonics)

  11. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  12. Relaxation Time of High-Density Amorphous Ice

    Science.gov (United States)

    Handle, Philip H.; Seidl, Markus; Loerting, Thomas

    2012-06-01

    Amorphous water plays a fundamental role in astrophysics, cryoelectron microscopy, hydration of matter, and our understanding of anomalous liquid water properties. Yet, the characteristics of the relaxation processes taking place in high-density amorphous ice (HDA) are unknown. We here reveal that the relaxation processes in HDA at 110-135 K at 0.1-0.2 GPa are of collective and global nature, resembling the alpha relaxation in glassy material. Measured relaxation times suggest liquid-like relaxation characteristics in the vicinity of the crystallization temperature at 145 K. By carefully relaxing pressurized HDA for several hours at 135 K, we produce a state that is closer to the ideal glass state than all HDA states discussed so far in literature.

  13. Cross-relaxation in multiple pulse NQR spin-locking

    Energy Technology Data Exchange (ETDEWEB)

    Beltjukov, P. A.; Kibrik, G. E. [Perm State University, Physics Department (Russian Federation); Furman, G. B., E-mail: gregoryf@bgu.ac.il; Goren, S. D. [Ben Gurion University, Physics Department (Israel)

    2008-01-15

    The experimental and theoretical NQR multiple-pulse spin locking study of cross-relaxation process in solids containing nuclei of two different sorts I > 1/2 and S = 1/2 coupled by the dipole-dipole interactions and influenced by an external magnetic field. Two coupled equations for the inverse spin temperatures of the both spin systems describing the mutual spin lattice relaxation and the cross-relaxation were obtained using the method of the nonequilibrium state operator. It is shown that the relaxation process is realized with non-exponential time dependence describing by a sum of two exponents. The cross relaxation time is calculated as a function of the multiple-pulse field parameters which agree with the experimental data. The calculated magnetization cross relaxation time vs the strength of the applied magnetic field agrees well with the obtained experimental data.

  14. Experiments in paramagnetic relaxation

    International Nuclear Information System (INIS)

    Lijphart, E.E.

    1976-01-01

    This thesis presents two attempts to improve the resolving power of the relaxation measurement technique. The first attempt reconsiders the old technique of steady state saturation. When used in conjunction with the pulse technique, it offers the possibility of obtaining additional information about the system in which all-time derivatives are zero; in addition, non-linear effects may be distinguished from each other. The second attempt involved a systematic study of only one system: Cu in the Tutton salts (K and Rb). The systematic approach, the high accuracy of the measurement and the sheer amount of experimental data for varying temperature, magnetic field and concentration made it possible in this case to separate the prevailing relaxation mechanisms reliably

  15. Relaxation from particle production

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Marques-Tavares, Gustavo [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States)

    2016-12-20

    We consider using particle production as a friction force by which to implement a “Relaxion” solution to the electroweak hierarchy problem. Using this approach, we are able to avoid superplanckian field excursions and avoid any conflict with the strong CP problem. The relaxation mechanism can work before, during or after inflation allowing for inflationary dynamics to play an important role or to be completely decoupled.

  16. Frequency of deflagration in the in-tank precipitation process tanks due to loss of nitrogen purge system

    International Nuclear Information System (INIS)

    Jansen, J.M.; Mason, C.L.; Olsen, L.M.; Shapiro, B.J.; Gupta, M.K.; Britt, T.E.

    1994-01-01

    High-level liquid wastes (HLLW) from the processing of nuclear material at the Savannah River Site (SRS) are stored in large tanks in the F- and H-Area tank farms. The In-Tank Precipitation (ITP) process is one step in the processing and disposal of HLLW. The process hazards review for the ITP identified the need to implement provisions that minimize deflagration/explosion hazards associated with the process. The objective of this analysis is to determine the frequency of a deflagration in Tank 48 and/or 49 due to nitrogen purge system failures (including external events) and coincident ignition source. A fault tree of the nitrogen purge system coupled with ignition source probability is used to identify dominant system failures that contribute to the frequency of deflagration. These system failures are then used in the recovery analysis. Several human actions, recovery actions, and repair activities are identified that reduce total frequency. The actions are analyzed and quantified as part of a Human Reliability Analysis (HRA). The probabilities of failure of these actions are applied to the fault tree cutsets and the event trees

  17. Magnetic relaxation in anisotropic magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1971-01-01

    The line shape and the kinematic and thermodynamic slowing down of the critical and paramagnetic relaxation in axially anisotropic materials are discussed. Kinematic slowing down occurs only in the longitudinal relaxation function. The thermodynamic slowing down occurs in either the transverse...... or longitudinal relaxation function depending on the sign of the axial anisotropy....

  18. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro

    2006-01-01

    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  19. Excited-state relaxation of some aminoquinolines

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants ( k f of 2-amino-3-( 2 ′ -benzoxazolylquinoline (I, 2-amino-3-( 2 ′ -benzothiazolylquinoline (II, 2-amino-3-( 2 ′ -methoxybenzothiazolyl-quinoline (III, 2-amino-3-( 2 ′ -benzothiazolylbenzoquinoline (IV at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol as the temperature decreases (the solvent viscosity increases points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant k f (up to about 7 times as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.

  20. Dielectric relaxations above room temperature in DMPU derived polyaniline film

    Energy Technology Data Exchange (ETDEWEB)

    Mallya, Ashwini N.; Yashavanth Kumar, G.S.; Ranjan, Rajeev [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Ramamurthy, Praveen C., E-mail: onegroupb203@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2012-09-15

    Dielectric measurements carried out on drop casted from solution of emeraldine base form of polyaniline films in the temperature range 30-300 Degree-Sign C revealed occurrence of two maxima in the loss tangent as a function of temperature. The activation energies corresponding to these two relaxation processes were found to be {approx}0.5 eV and {approx}1.5 eV. The occurrence of one relaxation peak in the dispersion curve of the imaginary part of the electric modulus suggests the absence of microphase separation in the film. Thermogravimetric analysis and infrared spectroscopic measurements showed that the films retained its integrity up to 300 Degree-Sign C. The dielectric relaxation at higher temperatures with large activation energy of 1.5 eV is attributed to increase in the barrier potential due to decrease in the polymer conjugation as a result of wide amplitude motion of the chain segments well above the glass transition temperature.

  1. Momentum and mass relaxation in heavy-ion collisions

    International Nuclear Information System (INIS)

    Gregoire, C.; Scheuter, F.; Remaud, B.; Sebille, F.

    1984-01-01

    The momentum and mass relaxation are shown to be described by transport equations. The momentum relaxation, which can be studied in the intermediate energy regime by the particle emissions, refers to a microscopic slowing down and diffusion process in the momentum space. The mass relaxation refers to the coupling of the collective mass asymmetry degree of freedom and the intrinsic system. It can be illustrated by the fast fission of light and very heavy systems

  2. Relaxation and Diffusion in Complex Systems

    CERN Document Server

    Ngai, K L

    2011-01-01

    Relaxation and Diffusion in Complex Systems comprehensively presents a variety of experimental evidences of universal relaxation and diffusion properties in complex materials and systems. The materials discussed include liquids, glasses, colloids, polymers, rubbers, plastic crystals and aqueous mixtures, as well as carbohydrates, biomolecules, bioprotectants and pharmaceuticals. Due to the abundance of experimental data, emphasis is placed on glass-formers and the glass transition problem, a still unsolved problem in condensed matter physics and chemistry. The evidence for universal properties of relaxation and diffusion dynamics suggests that a fundamental physical law is at work. The origin of the universal properties is traced to the many-body effects of the interaction, rigorous theory of which does not exist at the present time. However, using solutions of simplified models as guides, key quantities have been identified and predictions of the universal properties generated. These predictions from Ngai’...

  3. Influence of radioactive contamination to agricultural products due to dry and wet deposition processes during a nuclear emergency

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Han, Moon Hee; Choi, Yong Ho; Lee, Chang Woo

    2002-01-01

    Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than dry deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants

  4. Vogel-Fulcher dependence of relaxation rates in a nematic monomer and elastomer

    Science.gov (United States)

    Shenoy, D.; Filippov, S.; Aliev, F.; Keller, P.; Thomsen, D.; Ratna, B.

    2000-12-01

    Dielectric relaxation spectroscopy is used to study the relaxation processes in a nematic monomer and the corresponding cross-linked polymer nematic liquid crystal (elastomer). In the frequency window 10 mHz to 2 GHz the monomer liquid crystal shows a single relaxation whereas the polymer exhibits three relaxation processes, two of which are quantitatively analyzed. The temperature dependence of relaxation times in both the monomer and polymer follows a Vogel-Fulcher behavior. The relaxation processes are identified with specific molecular motions and activation energies are calculated in a linear approximation for comparison with literature data.

  5. Analysis of the Processes in Spent Fuel Pools in Case of Loss of Heat Removal due to Water Leakage

    Directory of Open Access Journals (Sweden)

    Algirdas Kaliatka

    2013-01-01

    Full Text Available The safe storage of spent fuel assemblies in the spent fuel pools is very important. These facilities are not covered by leaktight containment; thus, the consequences of overheating and melting of fuel in the spent fuel pools can be very severe. On the other hand, due to low decay heat of fuel assemblies, the processes in pools are slow in comparison with processes in reactor core during LOCA accident. Thus, the accident management measures play a very important role in case of some accidents in spent fuel pools. This paper presents the analysis of possible consequences of fuel overheating due to leakage of water from spent fuel pool. Also, the accident mitigation measure, the late injection of water was evaluated. The analysis was performed for the Ignalina NPP Unit 2 spent fuel pool, using system thermal hydraulic code for severe accident analysis ATHLET-CD. The phenomena, taking place during such accident, are discussed. Also, benchmarking of results of the same accident calculation using ASTEC and RELAP/SCDAPSIM codes is presented here.

  6. U.S. Case Law and Legal Precedent Affirming the Due Process Rights of Immigrants Fleeing Persecution.

    Science.gov (United States)

    Sidhu, Shawn S; Boodoo, Ramnarine

    2017-09-01

    The political discourse on domestic immigration policy has shifted rapidly in recent years, mirrored by similar shifts in the geopolitical climate worldwide. However, a nuanced assessment of the legal basis backing such rhetoric is sorely lacking. This article examines the historical, legal, and case law precedent as it pertains specifically to immigrants who are fleeing persecution and residing within the United States. Due process rights emerged from the Fifth, Sixth, and Fourteenth Constitutional Amendments and have been expanded to include this population through several sequential United States Supreme Court Cases. We review the 1951 Convention Related to the Status of Refugees and 1967 Protocol Relating to the Status of Refugees and examine subsequent case law and legal precedent. We then present evidence documenting widespread violations of due process rights for immigrants fleeing persecution. Specifically, we address the right to a fair hearing for individuals fearing for their lives upon return to their home country, the right against wrongful detainment, and the right to apply for asylum regardless of religion or country of origin. We conclude by addressing potential counterarguments to our thesis, future directions, and the role of forensic psychiatrists. © 2017 American Academy of Psychiatry and the Law.

  7. Spin relaxation of iron in mixed state hemoproteins

    International Nuclear Information System (INIS)

    Wajnberg, E.; Kalinowski, H.J.; Bemski, G.; Helman, J.S.

    1984-01-01

    In pure states hemoproteins the relaxation of iron depends on its spin state. It is found that in both mixed state met-hemoglobin and met-myoglobin, the low and high spin states relax through an Orbach-like process. Also, very short (approx. 1 ns) and temperature independent transverse relaxation times T 2 were estimated. This peculiar behaviour of the relaxation may result from the unusual electronic structure of mixed state hemoproteins that allows thermal equilibrium and interconversion of the spin states. (Author) [pt

  8. Green--Kubo formula for collisional relaxation

    International Nuclear Information System (INIS)

    Visscher, P.B.

    1988-01-01

    In this paper we generalize the Green--Kubo method (usually used for obtaining formulas for transport coefficients involving conserved densities) to relaxation processes occurring during collisions, such as the transfer of energy from vibrational to translational modes in a molecular fluid. We show that the relaxation rate can be calculated without evaluating time correlation functions over long times, and can in fact be written as a sum over collisions which makes the relation between the Green--Kubo method and approximate independent-collision models much clearer

  9. Simulation study of stepwise relaxation in a spheromak plasma

    International Nuclear Information System (INIS)

    Horiuchi, Ritoku; Uchida, Masaya; Sato, Tetsuya.

    1991-10-01

    The energy relaxation process of a spheromak plasma in a flux conserver is investigated by means of a three-dimensional magnetohydrodynamic simulation. The resistive decay of an initial force-free profile brings the spheromak plasma to an m = 1/n = 2 ideal kink unstable region. It is found that the energy relaxation takes place in two steps; namely, the relaxation consists of two physically distinguished phases, and there exists an intermediate phase in between, during which the relaxation becomes inactive temporarily. The first relaxation corresponds to the transition from an axially symmetric force-free state to a helically symmetric one with an n = 2 crescent magnetic island structure via the helical kink instability. The n = 2 helical structure is nonlinearly sustained in the intermediate phase. The helical twisting of the flux tube creates a reconnection current in the vicinity of the geometrical axis. The second relaxation is triggered by the rapid growth of the n = 1 mode when the reconnection current exceeds a critical value. The helical twisting relaxes through magnetic reconnection toward an axially symmetric force-free state. It is also found that the poloidal flux reduces during the helical twisting in the first relaxation and the generation of the toroidal flux occurs through the magnetic reconnection process in the second relaxation. (author)

  10. Waveform relaxation methods for implicit differential equations

    NARCIS (Netherlands)

    P.J. van der Houwen; W.A. van der Veen

    1996-01-01

    textabstractWe apply a Runge-Kutta-based waveform relaxation method to initial-value problems for implicit differential equations. In the implementation of such methods, a sequence of nonlinear systems has to be solved iteratively in each step of the integration process. The size of these systems

  11. Transformation-Induced Relaxation and Stress Recovery of TiNi Shape Memory Alloy

    Directory of Open Access Journals (Sweden)

    Kohei Takeda

    2014-03-01

    Full Text Available The transformation-induced stress relaxation and stress recovery of TiNi shape memory alloy (SMA in stress-controlled subloop loading were investigated based on the local variation in temperature and transformation band on the surface of the tape in the tension test. The results obtained are summarized as follows. (1 In the loading process, temperature increases due to the exothermic martensitic transformation (MT until the holding strain and thereafter temperature decreases while holding the strain constant, resulting in stress relaxation due to the MT; (2 In the unloading process, temperature decreases due to the endothermic reverse transformation until the holding strain and thereafter temperature increases while holding the strain constant, resulting in stress recovery due to the reverse transformation; (3 Stress varies markedly in the initial stage followed by gradual change while holding the strain constant; (4 If the stress rate is high until the holding strain in the loading and unloading processes, both stress relaxation and stress recovery are large; (5 It is important to take into account this behavior in the design of SMA elements, since the force of SMA elements varies even if the atmospheric temperature is kept constant.

  12. Muon spin relaxation in ferromagnets. Pt. 1

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Karlsson, E.B.

    1991-04-01

    Expressions for the dipolar and hyperfine contributions to the relaxation rate of muons implanted in a ferromagnet are presented and analysed using the Heisenberg model of spin-waves including dipolar and Zeeman energies. Calculations for EuO indicate that relaxation is likely to be dominated by the hyperfine mechanism, even if the ratio of the hyperfine and dipolar coupling constants is small. The hyperfine mechanism is sensitive to the dipolar energy of the atomic spins, whereas the dipolar mechanisms depend essentially on the exchange energy. For both mechanisms there is an almost quadratic dependence on temperature, throughout much of the ordered magnetic phase, which reflects two-spin-wave difference events from the Raman-type relaxation processes. (author)

  13. Variational formulation of relaxed and multi-region relaxed magnetohydrodynamics

    Science.gov (United States)

    Dewar, R. L.; Yoshida, Z.; Bhattacharjee, A.; Hudson, S. R.

    2015-12-01

    > Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic reconnection. By contrast, in the Taylor relaxation model for formation of macroscopically self-organized plasma equilibrium states, all these constraints are relaxed save for the global magnetic fluxes and helicity. A Lagrangian variational principle is presented that leads to a new, fully dynamical, relaxed magnetohydrodynamics (RxMHD), such that all static solutions are Taylor states but also allows state with flow. By postulating that some long-lived macroscopic current sheets can act as barriers to relaxation, separating the plasma into multiple relaxation regions, a further generalization, multi-region relaxed magnetohydrodynamics (MRxMHD) is developed.

  14. Retardation of the dewetting process due to the addition of functional copolymers at polymer-polymer interfaces

    CERN Document Server

    Wunnicke, O; Lorenz-Haas, C; Leiner, V

    2002-01-01

    We studied the retardation of the dewetting process due to the addition of a functional copolymer in a polymer bilayer film. The model system consists of fully deuterated polystyrene (PS-d) on top of an amorphous polyamide (PA) sublayer on silicon substrates. Bilayer films were prepared with different content (0, 5, 10 and 30 vol. %) of a statistical copolymer (protonated styrene maleic anhydride acid (SMA2) containing 2% MA groups along the chain) being capable of forming hydrogen bonds with PA. The as-prepared as well as the annealed samples were investigated by neutron-reflectivity (NR) experiments, scanning force microscopy and optical microscopy. A significant retardation of dewetting is observed with the addition of SMA2. From model fits of NR curves the scattering length density profiles perpendicular to the sample surface were determined and an enrichment layer of SMA2 is detected. Retardation is explained by the intermixing of SMA2 and PS-d at the interface. (orig.)

  15. Study of test-mass charging process in the LISA missions due to diffuse γ-rays

    International Nuclear Information System (INIS)

    Finetti, N; Scrimaglio, R; Grimani, C; Fabi, M

    2009-01-01

    Gravitational inertial sensors will be placed on board the Laser Interferometer Space Antenna (LISA) and aboard its precursor mission LISA Pathfinder (LISA-PF) in order to detect low frequency gravitational waves in space. Free-floating test-masses (Au 7 Pt 3 cubes) will be housed in inertial sensors for detecting possible laser signal variations induced by gravitational waves. Charging of the LISA test-masses due to exposure of the spacecraft to cosmic radiation and energetic solar particles will affect operation of gravitational inertial sensors. In this paper we report on the role of diffuse γ-rays in charging the LISA and LISA-PF test-masses with respect to protons and helium nuclei. The diffuse γ-ray flux in the Galaxy has been interpolated taking into account the outcomes of recent calculations. A comparison with γ-ray observations gathered by different experiments (COMPTEL and EGRET, Milagro, Whipple, HEGRA, TIBET) has been carried out. Simulations of the test-mass charging process have been performed by means of the FLUKA2006.3b package. Monte Carlo simulations of the interaction of cosmic particles with the LISA spacecraft indicate that the diffuse γ-ray contribution to the average steady-state test-mass charging rate and to the single-sided power spectrum of the charge rate noise is marginal with respect to that due to galactic cosmic-rays.

  16. Plasma relaxation of cold electrons and hot ions

    International Nuclear Information System (INIS)

    Potapenko, I.F.; Sakanaka, P.H.

    1996-01-01

    The relaxation process of a space uniform plasma composed of cold electrons and one species of hot ions studied numerically. Special attention has been paid to the deviation of relaxation from the classical picture which is characterized by a weakly non-isothermic situation. (author). 6 refs., 2 figs

  17. Dynamics of relaxed inflation

    Science.gov (United States)

    Tangarife, Walter; Tobioka, Kohsaku; Ubaldi, Lorenzo; Volansky, Tomer

    2018-02-01

    The cosmological relaxation of the electroweak scale has been proposed as a mechanism to address the hierarchy problem of the Standard Model. A field, the relaxion, rolls down its potential and, in doing so, scans the squared mass parameter of the Higgs, relaxing it to a parametrically small value. In this work, we promote the relaxion to an inflaton. We couple it to Abelian gauge bosons, thereby introducing the necessary dissipation mechanism which slows down the field in the last stages. We describe a novel reheating mechanism, which relies on the gauge-boson production leading to strong electro-magnetic fields, and proceeds via the vacuum production of electron-positron pairs through the Schwinger effect. We refer to this mechanism as Schwinger reheating. We discuss the cosmological dynamics of the model and the phenomenological constraints from CMB and other experiments. We find that a cutoff close to the Planck scale may be achieved. In its minimal form, the model does not generate sufficient curvature perturbations and additional ingredients, such as a curvaton field, are needed.

  18. Length of proceedings as standard of due process of law in the practise of the Constitutional Court of Albania

    Directory of Open Access Journals (Sweden)

    Elsa Toska Dobjani

    2016-01-01

    Full Text Available ECHR, as an international treaty is part of the Albanian legal system. Among international law instruments, the ECHR enjoys a privileged status in the Albanian legal system by virtue of Article 17 paragraph 2 of the Constitution according to which restrictions to human rights and freedoms cannot infringe the substance of those rights and freedoms and in no case can exceed the restrictions provided for in the ECHR. Article 1 of the Convention requires States to secure the substance of the rights to those in their jurisdiction. The effect of Article 13 is thus to require the provision of a domestic remedy to deal with the substance of an arguable complaint under the Convention and to grant appropriate relief. The scope of this paper is to analyse the effectiveness of the complaint to the Constitutional Court with regard to length of proceedings as part of due process of law in terms of proceedings during the court trial and after the process has been finalized and the final decision should be executed.

  19. Vibrational relaxation of a triatomic molecular impurity: D2O in vitreous As2S3

    International Nuclear Information System (INIS)

    Rella, C.W.; Schwettman, H.A.; Engholm, J.R.

    1995-01-01

    Measurements of the relaxation of the D 2 O stretch mode in vitreous As 2 S 3 are presented. Because the bending mode of the molecule offers an intra-molecular decay channel for the stretch mode, the decay scheme of the D 2 O molecule is more complex than that of diatomic molecules. The asymmetric stretch mode of D 2 O has a frequency of 2680 cm -1 . To study the relaxation of this mode we applied a pump-probe technique, using intense psec; pulses of the Stanford Free Electron Laser. Due to the small cross-section of the vibrational mode, successful efforts were made to improve the signal to noise ratio by using a laser stabilization system and a tightly focused beam to increase the intensity, by averaging the signal with a kHz repetition rate and by using samples with an optimized D 2 O concentration. A rapid relaxation rate on the order of 5 x 10 9 sec -1 at low temperature is found that increases with temperature. Recalling that the bending mode of the D 2 O molecule has a frequency of 1170 cm -1 , one would expect a decay in a third order process, involving two quanta of the bending mode plus a vibrational host quanta with a frequency of 340 cm -1 , which coincides with a fundamental frequency of the pyramidal building blocks of the glassy As 2 S 3 host. Instead, we find from the temperature dependence of the relaxation rate that the D 2 O stretching mode relaxes in a higher order process. This indicates that the relaxation dynamics of small molecules is more complex than generally assumed

  20. Process-oriented dose assessment model for 14C due to releases during normal operation of a nuclear power plant

    International Nuclear Information System (INIS)

    Aquilonius, Karin; Hallberg, Bengt

    2005-01-01

    Swedish nuclear utility companies are required to assess doses due to releases of radionuclides during normal operation. In 2001, calculation methods used earlier were updated due to new authority regulations. The isotope 14 C is of special interest in dose assessments due to the role of carbon in the metabolism of all life forms. Earlier, factors expressing the ratio between concentration of 14 C in air and in various plants were used. In order to extend the possibility to take local conditions into account, a process-oriented assessment model for uptake of carbon and doses from releases of 14 C to air was developed (POM 14 C). The model uses part of Daisy which has been developed to model the turnover of carbon in crops. [Hansen, S., Jensen, H.E., Nielsen, N.E., Svendsen, H., 1993. Description of the Soil Plant System Model DAISY, Basic Principles and Modelling Approach. Simulation Model for Transformation and Transport of Energy and Matter in the Soil Plant Atmosphere System. Jordbruksfoerlaget, The Royal Veterianary and Agricultural University, Copenhagen, Denmark]. The main objectives were to test model performance of the former method, and to investigate if taking site specific parameters into account to a greater degree would lead to major differences in the results. Several exposure pathways were considered: direct consumption of locally grown cereals, vegetables, and root vegetables, as well as consumption of milk and meat from cows having eaten fodder cereals and green fodder from the area around the nuclear plant. The total dose of the earlier model was compared with that of POM 14 C. The result of the former was shown to be slightly higher than the latter, but POM 14 C confirmed that the earlier results were of a reasonable magnitude. When full account of local conditions was taken, e.g. as regards solar radiation, temperature, and concentration of 14 C in air at various places in the surroundings of each nuclear plant, a difference in dose between

  1. The ultrasonic relaxation spectra for furfural molecules undergoing conformational changes

    International Nuclear Information System (INIS)

    Mirzaev, S. Z.; Telyaev, S. Q.; Egamberdiev, K.

    2011-01-01

    The acoustic spectra of liquid furfural have been investigated in the frequency range from 0.1MHz to 150 MHz and at the temperatures from 303.15 K to 333.15 K. The ultrasonic spectra of pure furfural show two relaxation processes. One relaxation process is located in the frequency range ∼0.2 MHz, and the second in the frequency range ∼2 MHz. The process with the lower relaxation frequency has been assigned to the 'X0-cis and X0-trans' internal rotation of furfural molecules. (authors)

  2. Milrinone relaxes pulmonary veins in guinea pigs and humans.

    Directory of Open Access Journals (Sweden)

    Annette D Rieg

    Full Text Available INTRODUCTION: The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH. However, its action on pulmonary veins (PVs is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs and humans. MATERIAL AND METHODS: Precision-cut lung slices (PCLS were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL. RESULTS: In the IPL (GP, milrinone (10 µM lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP, milrinone relaxed naïve and pre-constricted PVs (120% and this relaxation was attenuated by inhibition of protein kinase G (KT 5823, adenyl cyclase (SQ 22536 and protein kinase A (KT 5720, but not by inhibition of NO-synthesis (L-NAME. In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+- and Kv-channels. Human PVs also relaxed to milrinone (121%, however only if pre-constricted. DISCUSSION: Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

  3. Milrinone relaxes pulmonary veins in guinea pigs and humans.

    Science.gov (United States)

    Rieg, Annette D; Suleiman, Said; Perez-Bouza, Alberto; Braunschweig, Till; Spillner, Jan W; Schröder, Thomas; Verjans, Eva; Schälte, Gereon; Rossaint, Rolf; Uhlig, Stefan; Martin, Christian

    2014-01-01

    The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans. Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL). In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of K ATP-, BK Ca (2+)- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted. Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on K ATP-, BK Ca (2+)- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.

  4. Spiritual Occlusion and Systemic Integrity: Legal Evaluations of Due Process Protections and Freedom of Religious Expression and Practices Safeguards

    Directory of Open Access Journals (Sweden)

    Jason R. Jolicoeur

    2018-05-01

    Full Text Available As is the case with other constitutionally protected rights, the freedom of religion is not unlimited nor without restriction or constraint. Rather, the courts have long held that the state may have legitimate reasons for placing reasonable restrictions on the otherwise free exercise of religious practice. The courts have also held that the state cannot restrict religious practice in a capricious or gratuitous manner. However, the courts have also held that individuals have a constitutional right to due process legal protections. In many instances, these two freedoms exist independently of each other. In instances when they intersect, conflict may result from one right seeking hegemony over the other. In instances such as these, the courts may have to resolve conflicts by establishing legal principles and precedents regarding which of these constitutional protections will be granted contextual prominence over the other. Thus far, the legal evaluation of this important question has been confused at best and contradictory at worst. This has resulted in a number of substantive outcomes that pose significant challenges to the practice and application of both rights and an underlying avoidance of broader constitutional questions.

  5. Changes to processes in estuaries and coastal waters due to intense multiple pressures - An introduction and synthesis

    Science.gov (United States)

    Mitchell, Steven B.; Jennerjahn, Tim C.; Vizzini, Salvatrice; Zhang, Weiguo

    2015-04-01

    From the 2013 ECSA conference 'Estuaries and Coastal Areas in Times of Intense Change' a theme emerged that has ended up being the focus of this Special Issue of Estuarine Coastal and Shelf Science, namely 'Changes to processes in estuaries and coastal waters due to intense multiple pressures'. Many parts of the world are continuing to experience unprecedented rates of economic growth, and those responsible for managing coastal and estuarine areas must respond accordingly. At the same time, global climate change and sea level rise are also continuing, placing new or more intense pressures on coastal areas that must be dealt with in ways that are as far as possible managed as a result of good scientific understanding. There are other pressures too, which depend on the system concerned. This article provides an overview of the papers contained within the Special Issue and provides a discussion of how these fit within the main theme of intense multiple stressors, considering how a balance can be achieved between the needs of various different stakeholders and interest groups, and the sustainability of the system concerned. We categorise the papers in four main groupings: (1) stressors related to sea level rise; (2) stressors related to changes in fresh water inputs; (3) stressors related to anthropogenic pollution; and (4) the use of indicators as a means of assessing the effects of stressors, and reflect on the fact that despite the diversity of different challenges and geographical regions involved many of the approaches and discussions contained within the Special Issue have strong similarities, leading to a set of overarching principles that should be considered when making recommendations on management strategies.

  6. Dynamical relaxation in 2HDM models

    Science.gov (United States)

    Lalak, Zygmunt; Markiewicz, Adam

    2018-03-01

    Dynamical relaxation provides an interesting solution to the hierarchy problem in face of the missing signatures of any new physics in recent experiments. Through a dynamical process taking place in the inflationary phase of the Universe it manages to achieve a small electroweak scale without introducing new states observable in current experiments. Appropriate approximation makes it possible to derive an explicit formula for the final vevs in the double-scanning scenario extended to a model with two Higgs doublets (2HDM). Analysis of the relaxation in the 2HDM confirms that in a general case it is impossible to keep vevs of both scalars small, unless fine-tuning is present or additional symmetries are cast upon the Lagrangian. Within the slightly constrained variant of the 2HDM, where odd powers of the fields’ expectation values are not present (which can be easily enforced by requiring that the doublets have different gauge transformations or by imposing a global symmetry) it is shown that the difference between the vevs of two scalars tends to be proportional to the cutoff. The analysis of the relaxation in 2HDM indicates that in a general case the relaxation would be stopped by the first doublet that gains a vev, with the other one remaining vevless with a mass of the order of the cutoff. This happens to conform with the inert doublet model.

  7. Constraints on relaxation rates for N-level quantum systems

    International Nuclear Information System (INIS)

    Schirmer, S.G.; Solomon, A.I.

    2004-01-01

    We study the constraints imposed on the population and phase relaxation rates by the physical requirement of completely positive evolution for open N-level systems. The Lindblad operators that govern the evolution of the system are expressed in terms of observable relaxation rates, explicit formulas for the decoherence rates due to population relaxation are derived, and it is shown that there are additional, nontrivial constraints on the pure dephasing rates for N>2. Explicit, experimentally testable inequality constraints for the decoherence rates are derived for three- and four-level systems, and the implications of the results are discussed for generic ladder, Λ, and V systems and transitions between degenerate energy levels

  8. Stress relaxation and hillock growth in thin films

    International Nuclear Information System (INIS)

    Jackson, M.S.; Li, C.Y.

    1978-01-01

    The relaxation of thermal stress in a thin film adhering to a substrate of differing expansion coefficient is discussed. Good agreement is found between literature data on relaxation during isothermal anneals of Pb films at up to 350 0 K and model calculations based on a state variable description of plastic flow. The stress system during relaxation is explored, and the absence of diffusional creep is explained. The plasticity-dominated relaxation process suggested by this analysis is shown to be in good qualitative agreement with data on rapid relaxation over the course of a cycle between room and cryogenic temperatures. The implications of this for long-range material transport in the film are discussed. It is shown that hillock volume should increase over the course of a temperature cycle. Finally, a mechanism for hillock nucleation based on grain boundary sliding is suggested

  9. Mechanical properties of plant cell walls probed by relaxation spectra

    DEFF Research Database (Denmark)

    Hansen, Steen Laugesen; Ray, Peter Martin; Karlsson, Anders Ola

    2011-01-01

    Relax, that deduces relaxation spectra from appropriate rheological measurements is presented and made accessible through a Web interface. BayesRelax models the cell wall as a continuum of relaxing elements, and the ability of the method to resolve small differences in cell wall mechanical properties is demonstrated......Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild...... type. This may be due to the plant’s ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply...

  10. Axisymmetric force-free states and relaxation of a spheroidal spheromak

    International Nuclear Information System (INIS)

    Throumoulopoulos, G.N.; Pantis, G.

    1990-01-01

    Axisymmetric force-free equilibrium eigenstates for a prolate as well as an oblate spheroidal Spheromak with arbitrary elongation are obtained. In the framework of the Woltjer-Taylor relaxation theory the relaxed states are also identified. A simple hypothesis for the relaxation process is introduced, which implies that the plasma relaxes from multitoroidal formations to a singly toroidal configuration, in qualitative agreement with experimental results. (author)

  11. Axisymmetric force-free states and relaxation of a spheroidal spheromak

    International Nuclear Information System (INIS)

    Throumoulopoulos, G.N.; Pantis, G.

    1990-01-01

    Axisymmetric force-free equilibrium eigenstates for a prolate as well as an oblate spheroidal spheromak with arbitrary elongation are obtained. In the framework of the Woltjer-Taylor relaxation theory the relaxed states are also identified. A simple hypothesis for the relaxation process is introduced which implies that the plasma relaxes from multitoroidal formations to a singly toroidal configuration in qualitative agreement with experimental results. (Author)

  12. Modern problems of relaxation gas dynamics

    International Nuclear Information System (INIS)

    Losev, S.A.; Osipov, A.I.

    1985-01-01

    Some of the dynamical characteristics of relaxation processes are studied. Unfortunately, many dynamical characteristics of relaxation processes, necessary for the solution of important scientific and applied problems, are not known. These problems require further development of experimental methods of the study of nonequilibrium gas. It is known, that gas systems are shifted from the equilibrium by different methods: by acoustic and shock wav es, by means of gas expansion in nozzles and jets, by powerful radiations (laser, first of all), by electric discharges, in burning and combustion devices, etc. Non-equilibrium gas is produced in installations of continuum, impulse and periodic regime. Molecular beams, shock tubes (especially with nozzles), flow and jet installations, aerodynamical tubes, plasmatrons, vessels with a gas, influenced by the strong radiation, burners and combustion devices, where the study of non-euilibrium gas is helpful to solve the problems of the determination of kinetic equations and constants of physico-chemical kinetics

  13. Microplastic relaxations of single and polycrystalline molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Pichl, W.; Weiss, B. [Wien Univ. (Austria). Inst. fuer Materialphysik; Chen, D.L.

    1998-05-01

    The microplasticity of high-purity molybdenum single crystals and of Mo polycrystals of technical purity has been investigated by relaxation step tests in uniaxial compression. A new model for the evaluation of relaxation tests in the microplastic range of b.c.c metals is presented which takes into account the decrease of the mobile dislocation density due to exhaustion of non-screw dislocations. The model allows an independent determination of the activation volume and of the microstructure parameters controlling dislocation exhaustion. The results indicate that in the high-purity single crystals the deformation rate is controlled by interactions of non-screw dislocations with the grown-in network. In the polycrystals additional interactions with impurity atoms seem to occur. In the single crystals the activity and subsequent exhaustion of two different glide systems was observed, followed by a gradual onset of screw dislocation motion. (orig.) 26 refs.

  14. Are the different gully morphologies due to different formation processes on the Kaiser dune field on Mars?

    Science.gov (United States)

    Pasquon, K.; Gargani, J.; Nachon, M.; Conway, S. J.; Massé, M.; Jouannic, G.; Balme, M. R.; Costard, F.; Vincendon, M.

    2017-12-01

    Diverse gully morphologies are seen on Mars and differences are often neglected for simplification. Here we describe in detail the morphology and present-day activity of two gully-systems on the Kaiser dune field in the southern hemisphere of Mars. We then compare their activity with that of the morphologically distinct linear dune gullies present on the same dunes. The studied gully-systems have large depositional aprons (named "large apron gullies") and occur on dune faces oriented westward. They are active from mid-autumn to late winter (i.e. from Ls 50° to Ls 180°) coinciding with CO2 ice condensation/sublimation cycles. Sandy material collapses from the alcove flanks onto the alcove floor sporadically throughout this period. This accumulated sand is remobilized by punctuated mass flows which we estimate to be up to 7100 m3 in volume. These flows run out on to the apron and occur between Ls 120° and Ls 160°. These mass flow events occur when the number of "digitate flows" is at its seasonal maximum. Digitate flows are characterized by long-narrow zig-zagging low-albedo tracks and do not seem to transport appreciable sediment, and they can number in the hundreds. Small pits appear at their termini or midway along and sometimes these pits are re-deepened by subsequent flows. These events repeat every year and using volume balance calculations we find that the whole system could be built on a timescale of hundreds of martian ears. These large apron gullies differ in morphology and timing from the linear dune gullies. The linear dune gullies are active in late winter, or beginning of spring when the CO2 frost finally sublimates, which occurs after the activity of the large apron gullies. Due to the difference of orientation between large apron gullies and linear dune as well as timing, we infer that insolation, which may influence (i) the depth to ground ice, (ii) the amount of volatiles deposits, is the main cause their differences. Sediment transport by CO2

  15. Relaxed states with plasma flow

    International Nuclear Information System (INIS)

    Avinash, K.; Taylor, J.B.

    1991-01-01

    In the theory of relaxation, a turbulent plasma reaches a state of minimum energy subject to constant magnetic helicity. In this state the plasma velocity is zero. Attempts have been made by introducing a number of different constraints, to obtain relaxed states with plasma flow. It is shown that these alternative constraints depend on two self-helicities, one for ions, and one for electrons. However, whereas there are strong arguments for the effective invariance of the original magnetic-helicity, these arguments do not apply to the self-helicities. Consequently the existence of relaxed states with flow remains in doubt. (author)

  16. High temperature dielectric relaxation anomaly of Y3+ and Mn2+ doped barium strontium titanate ceramics

    International Nuclear Information System (INIS)

    Yan, Shiguang; Mao, Chaoliang; Wang, Genshui; Yao, Chunhua; Cao, Fei; Dong, Xianlin

    2014-01-01

    Relaxation like dielectric anomaly is observed in Y 3+ and Mn 2+ doped barium strontium titanate ceramics when the temperature is over 450 K. Apart from the conventional dielectric relaxation analysis method with Debye or modified Debye equations, which is hard to give exact temperature dependence of the relaxation process, dielectric response in the form of complex impedance, assisted with Cole-Cole impedance model corrected equivalent circuits, is adopted to solve this problem and chase the polarization mechanism in this paper. Through this method, an excellent description to temperature dependence of the dielectric relaxation anomaly and its dominated factors are achieved. Further analysis reveals that the exponential decay of the Cole distribution parameter n with temperature is confirmed to be induced by the microscopic lattice distortion due to ions doping and the interaction between the defects. At last, a clear sight to polarization mechanism containing both the intrinsic dipolar polarization and extrinsic distributed oxygen vacancies hopping response under different temperature is obtained.

  17. State resolved vibrational relaxation modeling for strongly nonequilibrium flows

    Science.gov (United States)

    Boyd, Iain D.; Josyula, Eswar

    2011-05-01

    Vibrational relaxation is an important physical process in hypersonic flows. Activation of the vibrational mode affects the fundamental thermodynamic properties and finite rate relaxation can reduce the degree of dissociation of a gas. Low fidelity models of vibrational activation employ a relaxation time to capture the process at a macroscopic level. High fidelity, state-resolved models have been developed for use in continuum gas dynamics simulations based on computational fluid dynamics (CFD). By comparison, such models are not as common for use with the direct simulation Monte Carlo (DSMC) method. In this study, a high fidelity, state-resolved vibrational relaxation model is developed for the DSMC technique. The model is based on the forced harmonic oscillator approach in which multi-quantum transitions may become dominant at high temperature. Results obtained for integrated rate coefficients from the DSMC model are consistent with the corresponding CFD model. Comparison of relaxation results obtained with the high-fidelity DSMC model shows significantly less excitation of upper vibrational levels in comparison to the standard, lower fidelity DSMC vibrational relaxation model. Application of the new DSMC model to a Mach 7 normal shock wave in carbon monoxide provides better agreement with experimental measurements than the standard DSMC relaxation model.

  18. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  19. Relaxation effects in ferrous complexes

    International Nuclear Information System (INIS)

    Nicolini, C.; Mathieu, J.P.; Chappert, J.

    1976-01-01

    The slow relaxation mechanism of the Fe 2+ ion in the tri-fluorinated TF(acac) and hexafluorinated HF(acac) complexes of Fe(II) acetylacetonate was investigated. The 300K and 77K Moessbauer spectra for TF(acac) consist in a slightly asymmetric quadrupole doublet. On the contrary, at 4.2K the higher energy line is strongly widened; that is typical of a slowing down in the electron relaxation frequency [fr

  20. Non-monotonic behaviour in relaxation dynamics of image restoration

    International Nuclear Information System (INIS)

    Ozeki, Tomoko; Okada, Masato

    2003-01-01

    We have investigated the relaxation dynamics of image restoration through a Bayesian approach. The relaxation dynamics is much faster at zero temperature than at the Nishimori temperature where the pixel-wise error rate is minimized in equilibrium. At low temperature, we observed non-monotonic development of the overlap. We suggest that the optimal performance is realized through premature termination in the relaxation processes in the case of the infinite-range model. We also performed Markov chain Monte Carlo simulations to clarify the underlying mechanism of non-trivial behaviour at low temperature by checking the local field distributions of each pixel

  1. Calorimetric and relaxation properties of xylitol-water mixtures

    Science.gov (United States)

    Elamin, Khalid; Sjöström, Johan; Jansson, Helén; Swenson, Jan

    2012-03-01

    We present the first broadband dielectric spectroscopy (BDS) and differential scanning calorimetry study of supercooled xylitol-water mixtures in the whole concentration range and in wide frequency (10-2-106 Hz) and temperature (120-365 K) ranges. The calorimetric glass transition, Tg, decreases from 247 K for pure xylitol to about 181 K at a water concentration of approximately 37 wt. %. At water concentrations in the range 29-35 wt. % a plentiful calorimetric behaviour is observed. In addition to the glass transition, almost simultaneous crystallization and melting events occurring around 230-240 K. At higher water concentrations ice is formed during cooling and the glass transition temperature increases to a steady value of about 200 K for all higher water concentrations. This Tg corresponds to an unfrozen xylitol-water solution containing 20 wt. % water. In addition to the true glass transition we also observed a glass transition-like feature at 220 K for all the ice containing samples. However, this feature is more likely due to ice dissolution [A. Inaba and O. Andersson, Thermochim. Acta, 461, 44 (2007)]. In the case of the BDS measurements the presence of water clearly has an effect on both the cooperative α-relaxation and the secondary β-relaxation. The α-relaxation shows a non-Arrhenius temperature dependence and becomes faster with increasing concentration of water. The fragility of the solutions, determined by the temperature dependence of the α-relaxation close to the dynamic glass transition, decreases with increasing water content up to about 26 wt. % water, where ice starts to form. This decrease in fragility with increasing water content is most likely caused by the increasing density of hydrogen bonds, forming a network-like structure in the deeply supercooled regime. The intensity of the secondary β-relaxation of xylitol decreases noticeably already at a water content of 2 wt. %, and at a water content above 5 wt. % it has been replaced by a

  2. Dissipation and the relaxation to equilibrium

    International Nuclear Information System (INIS)

    Evans, Denis J; Williams, Stephen R; Searles, Debra J

    2009-01-01

    Using the recently derived dissipation theorem and a corollary of the transient fluctuation theorem (TFT), namely the second-law inequality, we derive the unique time independent, equilibrium phase space distribution function for an ergodic Hamiltonian system in contact with a remote heat bath. We prove under very general conditions that any deviation from this equilibrium distribution breaks the time independence of the distribution. Provided temporal correlations decay, we show that any nonequilibrium distribution that is an even function of the momenta eventually relaxes (not necessarily monotonically) to the equilibrium distribution. Finally we prove that the negative logarithm of the microscopic partition function is equal to the thermodynamic Helmholtz free energy divided by the thermodynamic temperature and Boltzmann's constant. Our results complement and extend the findings of modern ergodic theory and show the importance of dissipation in the process of relaxation towards equilibrium

  3. Effective temperature in relaxation of Coulomb glasses.

    Science.gov (United States)

    Somoza, A M; Ortuño, M; Caravaca, M; Pollak, M

    2008-08-01

    We study relaxation in two-dimensional Coulomb glasses up to macroscopic times. We use a kinetic Monte Carlo algorithm especially designed to escape efficiently from deep valleys around metastable states. We find that, during the relaxation process, the site occupancy follows a Fermi-Dirac distribution with an effective temperature much higher than the real temperature T. Long electron-hole excitations are characterized by T(eff), while short ones are thermalized at T. We argue that the density of states at the Fermi level is proportional to T(eff) and is a good thermometer to measure it. T(eff) decreases extremely slowly, roughly as the inverse of the logarithm of time, and it should affect hopping conductance in many experimental circumstances.

  4. Local processing enhancements associated with superior observational drawing are due to enhanced perceptual functioning, not weak central coherence.

    Science.gov (United States)

    Chamberlain, Rebecca; McManus, I C; Riley, Howard; Rankin, Qona; Brunswick, Nicola

    2013-01-01

    Individuals with drawing talent have previously been shown to exhibit enhanced local visual processing ability. The aim of the current study was to assess whether local processing biases associated with drawing ability result from a reduced ability to cohere local stimuli into global forms, or an increased ability to disregard global aspects of an image. Local and global visual processing ability was assessed in art students and controls using the Group Embedded Figures Task, Navon shape stimuli, the Block Design Task and the Autism Spectrum Quotient, whilst controlling for nonverbal IQ and artistic ability. Local processing biases associated with drawing appear to arise from an enhancement of local processing alongside successful filtering of global information, rather than a reduction in global processing. The relationship between local processing and drawing ability is independent of individual differences in nonverbal IQ and artistic ability. These findings have implications for bottom-up and attentional theories of observational drawing, as well as explanations of special skills in autism.

  5. On the relaxation of cold electrons and hot ions

    International Nuclear Information System (INIS)

    Potapenko, I.F.; Bobylev, A.V.; Azevedo, C.A. de; Sakanaka, P.H.; Assis, A.S. de

    1998-01-01

    The relaxation process of a space uniform plasma composed of cold electrons and one species of hot ions is studied numerically using one- and two-dimensional Landau - Fokker - Planck codes. Relaxation of a monoenergetic ion beam is considered in possibly extreme temperature regimes. Special attention is paid to the deviation of the relaxation process from the classical picture, which is characterized by the close initial temperatures T e >(m e /m i ) 1/3 T i . The present results give quite a clear idea of the relaxation picture for any initial temperatures also in extreme temperature regimes. A difference scheme, preserving the number of particles and the energy, gives the possibility of solving the problem numerically without error accumulation, except for machine errors. copyright 1998 American Institute of Physics

  6. Theoretical model of intravascular paramagnetic tracers effect on tissue relaxation

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    2006-01-01

    The concentration of MRI tracers cannot be measured directly by MRI and is commonly evaluated indirectly using their relaxation effect. This study develops a comprehensive theoretical model to describe the transverse relaxation in perfused tissue caused by intravascular tracers. The model takes...... into account a number of individual compartments. The signal dephasing is simulated in a semianalytical way by embedding Monte Carlo simulations in the framework of analytical theory. This approach yields a tool for fast, realistic simulation of the change in the transverse relaxation. The results indicate...... with bulk blood. The enhancement of relaxation in tissue is due to the contrast in magnetic susceptibility between blood vessels and parenchyma induced by the presence of paramagnetic tracer. Beyond the perfusion measurements, the results can be applied to quantitation of functional MRI and to vessel size...

  7. Electron-Phonon Coupling and Resonant Relaxation from 1D and 1P States in PbS Quantum Dots.

    Science.gov (United States)

    Kennehan, Eric R; Doucette, Grayson S; Marshall, Ashley R; Grieco, Christopher; Munson, Kyle T; Beard, Matthew C; Asbury, John B

    2018-05-31

    Observations of the hot-phonon bottleneck, which is predicted to slow the rate of hot carrier cooling in quantum confined nanocrystals, have been limited to date for reasons that are not fully understood. We used time-resolved infrared spectroscopy to directly measure higher energy intraband transitions in PbS colloidal quantum dots. Direct measurements of these intraband transitions permitted detailed analysis of the electronic overlap of the quantum confined states that may influence their relaxation processes. In smaller PbS nanocrystals, where the hot-phonon bottleneck is expected to be most pronounced, we found that relaxation of parity selection rules combined with stronger electron-phonon coupling led to greater spectral overlap of transitions among the quantum confined states. This created pathways for fast energy transfer and relaxation that may bypass the predicted hot-phonon bottleneck. In contrast, larger, but still quantum confined nanocrystals did not exhibit such relaxation of the parity selection rules and possessed narrower intraband states. These observations were consistent with slower relaxation dynamics that have been measured in larger quantum confined systems. These findings indicated that, at small radii, electron-phonon interactions overcome the advantageous increase in energetic separation of the electronic states for PbS quantum dots. Selection of appropriately sized quantum dots, which minimize spectral broadening due to electron-phonon interactions while maximizing electronic state separation, is necessary to observe the hot-phonon bottleneck. Such optimization may provide a framework for achieving efficient hot carrier collection and multiple exciton generation.

  8. Flows of a Vapor due to Phase Change Processes at the Condensed Phases with Temperature Fields as their Internal Structures

    National Research Council Canada - National Science Library

    Onishi, Yoshimoto; Ooshida, Takeshi

    2005-01-01

    Transient to steady motions of a vapor caused by the evaporation and condensation processes occurring at the condensed phases placed in parallel have been studied based on the Boltzmann equation of BGK type...

  9. Batch Covariance Relaxation (BCR) Adaptive Processing.

    Science.gov (United States)

    1981-08-01

    leads to the equivalent bandpass transfer function K Pk-8) Bpp (s) =17 - 22 where C2I is the radian IF frequency normalized by wc. Assuming, tacitly...transfer function in (2-3) is given by H +(f + fE) = H+ Bpp (I + 6 ) (2-13) provided that f and f, are understood to be normalized by fc = wc/2r. In...4..J - tj, 45I2 a I a N 1A CZ~ IJ~oa 1,1 2.0 X : Z 1-3 1 a * N -- e - -o 0 (A -1- 1U z 0 8 Or I W *IA O! IU fau a :at oc- -MZ a Iaaa a a m :wU I..- 1

  10. Pulse Detonation Physiochemical and Exhaust Relaxation Processes

    Science.gov (United States)

    2006-05-01

    based on total time to detonation and detonation percentage. Nomenclature A = Arrehenius Constant Ea = Activation Energy Ecrit = Critical...the precision uncertainties vary for each data point. Therefore, the total experimental uncertainty will vary by data point. A comprehensive bias

  11. Attorney General forces Infectious Diseases Society of America to redo Lyme guidelines due to flawed development process.

    Science.gov (United States)

    Johnson, L; Stricker, R B

    2009-05-01

    Lyme disease is one of the most controversial illnesses in the history of medicine. In 2006 the Connecticut Attorney General launched an antitrust investigation into the Lyme guidelines development process of the Infectious Diseases Society of America (IDSA). In a recent settlement with IDSA, the Attorney General noted important commercial conflicts of interest and suppression of scientific evidence that had tainted the guidelines process. This paper explores two broad ethical themes that influenced the IDSA investigation. The first is the growing problem of conflicts of interest among guidelines developers, and the second is the increasing centralisation of medical decisions by insurance companies, which use treatment guidelines as a means of controlling the practices of individual doctors and denying treatment for patients. The implications of the first-ever antitrust investigation of medical guidelines and the proposed model to remediate the tainted IDSA guidelines process are also discussed.

  12. Biexciton relaxation associated with dissociation into a surface polariton pair in semiconductor films

    Science.gov (United States)

    Mitsumori, Yasuyoshi; Matsuura, Shimpei; Uchiyama, Shoichi; Saito, Kentarao; Edamatsu, Keiichi; Nakayama, Masaaki; Ajiki, Hiroshi

    2018-04-01

    We study the biexciton relaxation process in CuCl films ranging from 6 to 200 nm. The relaxation time is measured as the dephasing time and the lifetime. We observe a unique thickness dependence of the biexciton relaxation time and also obtain an ultrafast relaxation time with a timescale as short as 100 fs, while the exciton lifetime monotonically decreases with increasing thickness. By analyzing the exciton-photon coupling energy for a surface polariton, we theoretically calculate the biexciton relaxation time as a function of the thickness. The calculated dependence qualitatively reproduces the observed relaxation time, indicating that the biexciton dissociation into a surface polariton pair is one of the major biexciton relaxation processes.

  13. Phase-matched light amplification by three-wave mixing process in a birefringent fiber due to externally applied stress

    International Nuclear Information System (INIS)

    Ohashi, M.; Kitayama, K.; Ishida, Y.; Uchida, N.

    1982-01-01

    A novel method to achieve phase-matched light amplification in a birefringent fiber via the three-wave mixing is proposed by using frequency shift change due to the stress applied to the fiber. It is confirmed that the signal power from a cw laser diode at lambda = 1.292 μm is amplified by 6.1 x 10 3 times in the birefringent fiber pumped with a Q-switched Nd: yttrium aluminum garnet laser at lambda = 1.064 μm. This will provide a new fiber-optic light signal amplifier having a good tolerance for variation of signal wavelengths

  14. Probabilistic analysis and fatigue damage assessment of offshore mooring system due to non-Gaussian bimodal tension processes

    Science.gov (United States)

    Chang, Anteng; Li, Huajun; Wang, Shuqing; Du, Junfeng

    2017-08-01

    Both wave-frequency (WF) and low-frequency (LF) components of mooring tension are in principle non-Gaussian due to nonlinearities in the dynamic system. This paper conducts a comprehensive investigation of applicable probability density functions (PDFs) of mooring tension amplitudes used to assess mooring-line fatigue damage via the spectral method. Short-term statistical characteristics of mooring-line tension responses are firstly investigated, in which the discrepancy arising from Gaussian approximation is revealed by comparing kurtosis and skewness coefficients. Several distribution functions based on present analytical spectral methods are selected to express the statistical distribution of the mooring-line tension amplitudes. Results indicate that the Gamma-type distribution and a linear combination of Dirlik and Tovo-Benasciutti formulas are suitable for separate WF and LF mooring tension components. A novel parametric method based on nonlinear transformations and stochastic optimization is then proposed to increase the effectiveness of mooring-line fatigue assessment due to non-Gaussian bimodal tension responses. Using time domain simulation as a benchmark, its accuracy is further validated using a numerical case study of a moored semi-submersible platform.

  15. Relaxation and kinetics in scalar field theories

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Lawrie, I.D.; Lee, D.

    1996-01-01

    A new approach to the dynamics of relaxation and kinetics of thermalization in a scalar field theory is presented that incorporates the relevant time scales through the resummation of hard thermal loops. An alternative derivation of the kinetic equations for the open-quote open-quote quasiparticle close-quote close-quote distribution functions is obtained that allows a clear understanding of the different open-quote open-quote coarse-graining close-quote close-quote approximations usually involved in a kinetic description. This method leads to a systematic perturbative expansion to obtain the kinetic equations including hard thermal loop resummation and to an improvement including renormalization, off-shell effects, and contributions that change chemical equilibrium on short time scales. As a by-product of these methods we establish the equivalence between the relaxation time scale in the linearized equation of motion of the quasiparticles and the thermalization time scale of the quasiparticle distribution function in the open-quote open-quote relaxation time approximation close-quote close-quote including hard thermal loop effects. Hard thermal loop resummation dramatically modifies the scattering rate for long wavelength modes as compared to the usual (semi)classical estimate. Relaxation and kinetics are studied both in the unbroken and broken symmetry phases of the theory. The broken symmetry phase also provides the setting to obtain the contribution to the kinetic equations from processes that involve decay of a heavy scalar into light scalar particles in the medium. copyright 1996 The American Physical Society

  16. Altered joint tribology in osteoarthritis: Reduced lubricin synthesis due to the inflammatory process. New horizons for therapeutic approaches.

    Science.gov (United States)

    Szychlinska, M A; Leonardi, R; Al-Qahtani, M; Mobasheri, A; Musumeci, G

    2016-06-01

    Osteoarthritis (OA) is the most common form of joint disease. This review aimed to consolidate the current evidence that implicates the inflammatory process in the attenuation of synovial lubrication and joint tissue homeostasis in OA. Moreover, with these findings, we propose some evidence for novel therapeutic strategies for preventing and/or treating this complex disorder. The studies reviewed support that inflammatory mediators participate in the onset and progression of OA after joint injury. The flow of pro-inflammatory cytokines following an acute injury seems to be directly associated with altered lubricating ability in the joint tissue. The latter is associated with reduced level of lubricin, one of the major joint lubricants. Future research should focus on the development of new therapies that attenuate the inflammatory process and restore lubricin synthesis and function. This approach could support joint tribology and synovial lubrication leading to improved joint function and pain relief. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. A case of mental nerve paresthesia due to dynamic compression of alveolar inferior nerve along an elongated styloid process.

    Science.gov (United States)

    Gooris, Peter J J; Zijlmans, Jan C M; Bergsma, J Eelco; Mensink, Gertjan

    2014-07-01

    Spontaneous paresthesia of the mental nerve is considered an ominous clinical sign. Mental nerve paresthesia has also been referred to as numb chin syndrome. Several potentially different factors have been investigated for their role in interfering with the inferior alveolar nerve (IAN) and causing mental nerve neuropathy. In the present case, the patient had an elongated calcified styloid process that we hypothesized had caused IAN irritation during mandibular movement. This eventually resulted in progressive loss of sensation in the mental nerve region. To our knowledge, this dynamic irritation, with complete recovery after resection of the styloid process, has not been previously reported. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  18. The changes of astaxanthin content and chemical characteristics of tiger prawn (Penaeus monodon) due to processing: boiling, smoking and frying

    Science.gov (United States)

    Swastawati, F.

    2018-03-01

    Food processing using high temperatures can cause changes in pigment color and chemical characteristics in food stuffs, including prawn. The aim of this research was to evaluate the changes in pigment and chemical characteristics of tiger prawn caused by boiling, smoking and frying. Ten kg of tiger prawn was boiled, smoked and fried at the temperature of ± 100 °C for ± 10 min. The results showed that boiling, smoking and frying gave a significant effect (P < 0.05) on the astaxanthin pigment, pH, moisture, protein, salt content, Aw and color. The content of astaxanthin pigments in fresh prawn, boiled prawn, smoked prawn and fried prawn was: 132.79 ± 1.5 μg·g-1 82.89 ± 0.92 μg·g-1 78.28 ± 0.1 μg·g-1 and 91.35 ± 2.59 μg·g-1, respectively. The value of °Hue on fresh prawn, boiled prawn, smoked prawn and fried prawn was: 87.85° 52.5° 55.94° and 53.98°. The tiger prawn processed by the smoking method has preferable by panelist rather than processed by boiling and frying.

  19. Peeling mode relaxation ELM model

    International Nuclear Information System (INIS)

    Gimblett, C. G.

    2006-01-01

    This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made

  20. Relaxation-phenomena in LiAl/FeS-cells

    Science.gov (United States)

    Borger, W.; Kappus, W.; Panesar, H. S.

    A theoretical model of the capacity of strongly relaxing electrochemical systems is applied to the LiAl/FeS system. Relaxation phenomena in LiAl and FeS electrodes can be described by this model. Experimental relaxation data indicate that lithium transport through the alpha-LiAl layer to the particle surface is the capacity limiting process at high discharge current density in the LiAl electrode in LiCl-KCl and LiF-LiCl-LiBr mixtures. Strong relaxation is observed in the FeS electrode with LiCl-KCl electrolyte caused by lithium concentration gradients and precipitation of KCl in the pores.

  1. Dielectric relaxation studies of dilute solutions of amides

    Energy Technology Data Exchange (ETDEWEB)

    Malathi, M.; Sabesan, R.; Krishnan, S

    2003-11-15

    The dielectric constants and dielectric losses of formamide, acetamide, N-methyl acetamide, acetanilide and N,N-dimethyl acetamide in dilute solutions of 1,4-dioxan/benzene have been measured at 308 K using 9.37 GHz, dielectric relaxation set up. The relaxation time for the over all rotation {tau}{sub (1)} and that for the group rotation {tau}{sub (2)} of (the molecules were determined using Higasi's method. The activation energies for the processes of dielectric relaxation and viscous flow were determined by using Eyring's rate theory. From relaxation time behaviour of amides in non-polar solvent, solute-solvent and solute-solute type of molecular association is proposed.

  2. Thermomechanical Modeling of Laser-Induced Structural Relaxation and Deformation of Glass: Volume Changes in Fused Silica at High Temperatures [Thermo-mechanical modeling of laser-induced structural relaxation and deformation of SiO2 glass

    Energy Technology Data Exchange (ETDEWEB)

    Vignes, Ryan M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Ignition Facility and Photon Sciences; Soules, Thomas F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Ignition Facility and Photon Sciences; Stolken, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Ignition Facility and Photon Sciences; Settgast, Randolph R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Ignition Facility and Photon Sciences; Elhadj, Selim [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Ignition Facility and Photon Sciences; Matthews, Manyalibo J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Ignition Facility and Photon Sciences; Mauro, J.

    2012-12-17

    In a fully coupled thermomechanical model of the nanoscale deformation in amorphous SiO2 due to laser heating is presented. Direct measurement of the transient, nonuniform temperature profiles was used to first validate a nonlinear thermal transport model. Densification due to structural relaxation above the glass transition point was modeled using the Tool-Narayanaswamy (TN) formulation for the evolution of structural relaxation times and fictive temperature. TN relaxation parameters were derived from spatially resolved confocal Raman scattering measurements of Si–O–Si stretching mode frequencies. These thermal and microstructural data were used to simulate fictive temperatures which are shown to scale nearly linearly with density, consistent with previous measurements from Shelby et al. Volumetric relaxation coupled with thermal expansion occurring in the liquid-like and solid-like glassy states lead to residual stresses and permanent deformation which could be quantified. But, experimental surface deformation profiles between 1700 and 2000 K could only be reconciled with our simulation by assuming a roughly 2 × larger liquid thermal expansion for a-SiO2 with a temperature of maximum density ~150 K higher than previously estimated by Bruckner et al. Calculated stress fields agreed well with recent laser-induced critical fracture measurements, demonstrating accurate material response prediction under processing conditions of practical interest.

  3. Enhancement of the neutral-beam stopping cross section in fusion plasmas due to multistep collision processes

    International Nuclear Information System (INIS)

    Boley, C.D.; Janev, R.K.; Post, D.E.

    1983-10-01

    Multistep processes involving excited atomic states are found to produce a substantial increase in the stopping cross section for a neutral hydrogen beam injected into a plasma, and thus to reduce the beam penetration. For typical plasma and beam parameters of current large tokamak experiments, the stopping cross-sectional enhancement is found to vary from 25% to 50% depending on the beam energy, plasma density, and impurity level. For neutral hydrogen beams with energies greater than or equal to 500 keV, envisioned in tokamak amd mirror reactor designs, the enhancement can be as large as 80 to 90%

  4. Modelling of nitric acid production in the Advanced Cold Process Canister due to irradiation of moist air

    International Nuclear Information System (INIS)

    Henshaw, J.

    1994-01-01

    This report summarises the work performed for SKB of Sweden on the modelling of nitric acid production in the gaseous environment of the Advanced Cold Process Canister (ACPC). The model solves the simultaneous chemical rate equations describing the radiation chemistry of He/Ar/N 2 /O 2 /H 2 O gas mixture, involving over 200 chemical reactions. The amount of nitric acid produced as a function of time for typical ACPC conditions has been calculated using the model and the results reported. 11 refs, 11 figs, 1 tab

  5. Topology Synthesis of Structures Using Parameter Relaxation and Geometric Refinement

    Science.gov (United States)

    Hull, P. V.; Tinker, M. L.

    2007-01-01

    Typically, structural topology optimization problems undergo relaxation of certain design parameters to allow the existence of intermediate variable optimum topologies. Relaxation permits the use of a variety of gradient-based search techniques and has been shown to guarantee the existence of optimal solutions and eliminate mesh dependencies. This Technical Publication (TP) will demonstrate the application of relaxation to a control point discretization of the design workspace for the structural topology optimization process. The control point parameterization with subdivision has been offered as an alternative to the traditional method of discretized finite element design domain. The principle of relaxation demonstrates the increased utility of the control point parameterization. One of the significant results of the relaxation process offered in this TP is that direct manufacturability of the optimized design will be maintained without the need for designer intervention or translation. In addition, it will be shown that relaxation of certain parameters may extend the range of problems that can be addressed; e.g., in permitting limited out-of-plane motion to be included in a path generation problem.

  6. Thermal relaxation of molecular oxygen in collisions with nitrogen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Andrienko, Daniil A., E-mail: daniila@umich.edu; Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, 1320 Beal Ave., Ann Arbor, Michigan 48108 (United States)

    2016-07-07

    Investigation of O{sub 2}–N collisions is performed by means of the quasi-classical trajectory method on the two lowest ab initio potential energy surfaces at temperatures relevant to hypersonic flows. A complete set of bound–bound and bound–free transition rates is obtained for each precollisional rovibrational state. Special attention is paid to the vibrational and rotational relaxations of oxygen as a result of chemically non-reactive interaction with nitrogen atoms. The vibrational relaxation of oxygen partially occurs via the formation of an intermediate NO{sub 2} complex. The efficient energy randomization results in rapid vibrational relaxation at low temperatures, compared to other molecular systems with a purely repulsive potential. The vibrational relaxation time, computed by means of master equation studies, is nearly an order of magnitude lower than the relaxation time in N{sub 2}–O collisions. The rotational nonequilibrium starts to play a significant effect at translational temperatures above 8000 K. The present work provides convenient relations for the vibrational and rotational relaxation times as well as for the quasi-steady dissociation rate coefficient and thus fills a gap in data due to a lack of experimental measurements for this system.

  7. Numerical simulation of the bubble growth due to hydrogen isotopes inventory processes in plasma-irradiated tungsten

    International Nuclear Information System (INIS)

    Sang, Chaofeng; Sun, Jizhong; Bonnin, Xavier; Liu, Shengguang; Wang, Dezhen

    2013-01-01

    Hydrogen isotopes (HI) inventory is a key issue for fusion devices like ITER. It is especially urgent to understand how HI are retained in tungsten since it currently is the most important candidate material for the plasma-facing wall. Bubble growth is an important experimental complication that yet prevents a full understanding of HI retention processes in tungsten walls and most critically the divertor elements. In this work, we develop a model based on rate equations, which includes the bubble growth in tungsten being exposed to a HI plasma. In the model, HI molecules can be produced through recombination processes on the inner surface of a bubble, and HI molecules can also dissociate themselves to solute atoms, and the latter diffuse into the bulk wall because of very high pressures inside the bubble. The present model is applied to simulate how HI are retained in plasma-irradiated tungsten in the form of molecules to explain the wall temperature, trap concentration, incident HI flux and fluence dependencies of bubble growth

  8. Calcification in the staghorn coral Acropora acuminata: variations in apparent skeletal incorporation of radioisotopes due to different methods of processing

    International Nuclear Information System (INIS)

    Crossland, C.J.; Barnes, D.J.

    1977-01-01

    Pieces of branch from the staghorn coral Acropora acuminata were incubated with 45 CaCl 2 and NaH 14 CO 3 under identical conditions in the light or in the dark. Specimens were then processed in different ways. All specimens were placed in N KOH to digest tissues. Some were placed in KOH immediately after incubation; others were placed in KOH after 2 h washing, or after 2 h extraction with methanol-chloroform-water. Specimens were washed in running fresh water or running seawater; some were killed in liquid N 2 before washing. Radioactivity associated with skeleton and tissues was determined. The method of processing profoundly affected the results. In dark incubations, there was up to a four-fold difference in apparent skeletal incorporation of 45 Ca ++ between average values obtained for the different treatments. For 14 C incorporation, there was a difference of up to 2.5 times. In light incubations, skeletal incorporation of both radioisotopes showed a two-fold difference between high and low average values obtained for the different treatments. (orig.) [de

  9. Can a new behaviorally oriented training process to improve lifting technique prevent occupationally related back injuries due to lifting?

    Science.gov (United States)

    Lavender, Steven A; Lorenz, Eric P; Andersson, Gunnar B J

    2007-02-15

    A prospective randomized control trial. To determine the degree to which a new behavior-based lift training program (LiftTrainer; Ascension Technology, Burlington, VT) could reduce the incidence of low back disorder in distribution center jobs that require repetitive lifting. Most studies show programs aimed at training lifting techniques to be ineffective in preventing low back disorders, which may be due to their conceptual rather than behavioral learning approach. A total of 2144 employees in 19 distribution centers were randomized into either the LiftTrainer program or a video control group. In the LiftTrainer program, participants were individually trained in up to 5, 30-minute sessions while instrumented with motion capture sensors to quantify the L5/S1 moments. Twelve months following the initial training, injury data were obtained from company records. Survival analyses (Kaplan-Meier) indicated that there was no difference in injury rates between the 2 training groups. Likewise, there was no difference in the turnover rates. However, those with a low (<30 Nm) average twisting moment at the end of the first session experienced a significantly (P < 0.005) lower rate of low back disorder than controls. While overall the LiftTrainer program was not effective, those with twisting moments below 30 Nm reported fewer injuries, suggesting a shift in focus for "safe" lifting programs.

  10. A simple measurement method of molecular relaxation in a gas by reconstructing acoustic velocity dispersion

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Zhang, Xiangqun; Li, Caiyun

    2018-01-01

    Recently, a decomposition method of acoustic relaxation absorption spectra was used to capture the entire molecular multimode relaxation process of gas. In this method, the acoustic attenuation and phase velocity were measured jointly based on the relaxation absorption spectra. However, fast and accurate measurements of the acoustic attenuation remain challenging. In this paper, we present a method of capturing the molecular relaxation process by only measuring acoustic velocity, without the necessity of obtaining acoustic absorption. The method is based on the fact that the frequency-dependent velocity dispersion of a multi-relaxation process in a gas is the serial connection of the dispersions of interior single-relaxation processes. Thus, one can capture the relaxation times and relaxation strengths of N decomposed single-relaxation dispersions to reconstruct the entire multi-relaxation dispersion using the measurements of acoustic velocity at 2N  +  1 frequencies. The reconstructed dispersion spectra are in good agreement with experimental data for various gases and mixtures. The simulations also demonstrate the robustness of our reconstructive method.

  11. Supervisors’ experiences with the return-to-work process of hospital workers absent from work due to a health problem

    DEFF Research Database (Denmark)

    Stochkendahl, Mette Jensen; Myburgh, Corrie; Hartvigsen, Jan

    context. Aim: In order to gain knowledge about the potential role of supervisors in supporting RTW of a sick listed worker in Denmark, an exploratory qualitative pilot study will be conducted. We seek to open a window of understanding into the experience of managers who have been involved in RTW...... procedures, including the managers’ roles and contributions to the process. Methods: Using purposive sampling, approximately 20 hospital supervisors in charge of conducting sick leave interviews will participate in a face‐to‐face or focus group interviews in order to identify barriers and facilitators...... comparison analysis approach and computer assisted qualitative data analysis. Results: The study is in progress. Results will be available at the time of the conference. Conclusion: We will address questions regarding which factors supervisors feel are important to them in supporting returning workers...

  12. Analysis of residual stresses due to roll-expansion process: Finite element computation and validation by experimental tests

    International Nuclear Information System (INIS)

    Aufaure, M.; Boudot, R.; Zacharie, G.; Proix, J.M.

    1987-01-01

    The steam generator heat exchangers of pressurized water reactors are made of U-shaped tubes, both ends of them being fixed to a plate by roll-expansion. This process consists in increasing the tube section by means of a rotating tool in order to apply its outer side to the surface of the hole through the plate. As reported by de Keroulas (1986), in service cracks appeared on these tubes in the transition from expanded to nonexpanded portions. So we developed a program to compute residual stresses at the surface of the tubes, which caused their cracking, and to endeavour to lower their level by acting on some parameters. This program was validated by experimental tests. (orig.)

  13. Effectiveness of manual therapy versus surgery in pain processing due to carpal tunnel syndrome: A randomized clinical trial.

    Science.gov (United States)

    Fernández-de-Las-Peñas, C; Cleland, J; Palacios-Ceña, M; Fuensalida-Novo, S; Alonso-Blanco, C; Pareja, J A; Alburquerque-Sendín, F

    2017-08-01

    People with carpal tunnel syndrome (CTS) exhibit widespread pressure pain and thermal pain hypersensitivity as a manifestation of central sensitization. The aim of our study was to compare the effectiveness of manual therapy versus surgery for improving pain and nociceptive gain processing in people with CTS. The trial was conducted at a local regional Hospital in Madrid, Spain from August 2014 to February 2015. In this randomized parallel-group, blinded, clinical trial, 100 women with CTS were randomly allocated to either manual therapy (n = 50), who received three sessions (once/week) of manual therapies including desensitization manoeuvres of the central nervous system, or surgical intervention (n = 50) group. Outcomes including pressure pain thresholds (PPT), thermal pain thresholds (HPT or CPT), and pain intensity which were assessed at baseline, and 3, 6, 9 and 12 months after the intervention by an assessor unaware of group assignment. Analysis was by intention to treat with mixed ANCOVAs adjusted for baseline scores. At 12 months, 95 women completed the follow-up. Patients receiving manual therapy exhibited higher increases in PPT over the carpal tunnel at 3, 6 and 9 months (all, p < 0.01) and higher decrease of pain intensity at 3 month follow-up (p < 0.001) than those receiving surgery. No significant differences were observed between groups for the remaining outcomes. Manual therapy and surgery have similar effects on decreasing widespread pressure pain sensitivity and pain intensity in women with CTS. Neither manual therapy nor surgery resulted in changes in thermal pain sensitivity. The current study found that manual therapy and surgery exhibited similar effects on decreasing widespread pressure pain sensitivity and pain intensity in women with carpal tunnel syndrome at medium- and long-term follow-ups investigating changes in nociceptive gain processing after treatment in carpal tunnel syndrome. © 2017 European Pain Federation - EFIC®.

  14. Composition effect of potassium-borate glasses on their relaxation properties

    International Nuclear Information System (INIS)

    Lomovskoj, V.A.; Bartenev, G.M.

    1995-01-01

    Relaxation processes in potassium-borate glasses have been investigated in detail for the first time. It is shown that low-temperature β-process of relaxation relating to rotational mobility of the B-O bond is the same for all potassium-borate glasses and B 2 O 3 . The process of β k -relaxation related to diffusion mobility of potassium ions depends on the composition of the glasses in the same way as α-relaxation (glass formation).12 refs., 10 figs., 2 tabs

  15. Relaxation oscillations and transport barrier dynamics in tokamak edge plasmas

    International Nuclear Information System (INIS)

    Benkadda, Sadruddin; Beyer, Peter; Fuhr-Chaudier, Guillaume; Garbet, Xavier; Ghendrih, Philippe; Sarazin, Yanick

    2004-01-01

    Oscillations of turbulent transport of particles and energy in magnetically confined plasmas can be easily observed in simulations of a variety of turbulence models. These oscillations typically involve a mechanism of energy exchange between fluctuations and a poloidal shear flow. This kind of ''predator-prey'' mechanism is found to be not relevant for transport barrier relaxations. In RBM simulations of resistive ballooning turbulence with transport barrier, relaxation oscillations of the latter are observed even in the case of frozen poloidal shear flow. These relaxations are due to a transitory growth of a mode localized at the barrier center. A one-dimensional model for the evolution of such a mode in the presence of a shear flow describes a transitory growth of an initial perturbation. Oscillations in the case of a finite steady-state shear flow are possible due to the coupling of the mode to the dynamics of the pressure profile. (author)

  16. Constitutional Law--Procedural Due Process--Student Has Right to Have Attorney Present at University Disciplinary Hearing When Criminal Charges Are Pending.

    Science.gov (United States)

    Vessels, Rodney Jay

    1978-01-01

    In the case of Gabrilowitz v Newman the court used the due process balancing test to conclude that a student has a right to have counsel present at a university disciplinary hearing where the conduct in question is the object of a pending criminal proceeding. Available from J. Reuben Clark Law School, Brigham Young U., Provo, UT 84602. (MSE)

  17. The Substantive and Procedural Due Process Rights of Students Accused of Criminal Behavior in School and the Educational Rights of Adjudicated Youths.

    Science.gov (United States)

    Brown, Frank

    This paper--part of a collection of 54 papers from the 48th annual conference of the Education Law Association held in November 2002-- addresses juvenile justice. Its central issue is how to protect children of color in elementary and secondary schools with constitutional due process where attendance is compulsory and, at the same time, maintain a…

  18. On the propagation of linear transverse acoustic waves in isotropic media with mechanical relaxation phenomena due to viscosity and a tensorial internal variable. II. Some cases of special interest (Poynting-Thomson, Jeffreys, Maxwell, Kelvin-Voigt, Hooke and Newton media)

    NARCIS (Netherlands)

    Turrisi, E.; Ciancio, V.; Kluitenberg, G.A.

    1982-01-01

    The propagation of linear transverse acoustic waves in isotropic media in which mechanical relaxation phenomena occur was considered in a previous paper. In particular expressions for the velocity and attenuation of the waves were obtained and the limiting cases of waves with high and low

  19. Dependence of Brownian and Néel relaxation times on magnetic field strength

    International Nuclear Information System (INIS)

    Deissler, Robert J.; Wu, Yong; Martens, Michael A.

    2014-01-01

    Purpose: In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS) the relaxation time of the magnetization in response to externally applied magnetic fields is determined by the Brownian and Néel relaxation mechanisms. Here the authors investigate the dependence of the relaxation times on the magnetic field strength and the implications for MPI and MPS. Methods: The Fokker–Planck equation with Brownian relaxation and the Fokker–Planck equation with Néel relaxation are solved numerically for a time-varying externally applied magnetic field, including a step-function, a sinusoidally varying, and a linearly ramped magnetic field. For magnetic fields that are applied as a step function, an eigenvalue approach is used to directly calculate both the Brownian and Néel relaxation times for a range of magnetic field strengths. For Néel relaxation, the eigenvalue calculations are compared to Brown's high-barrier approximation formula. Results: The relaxation times due to the Brownian or Néel mechanisms depend on the magnitude of the applied magnetic field. In particular, the Néel relaxation time is sensitive to the magnetic field strength, and varies by many orders of magnitude for nanoparticle properties and magnetic field strengths relevant for MPI and MPS. Therefore, the well-known zero-field relaxation times underestimate the actual relaxation times and, in particular, can underestimate the Néel relaxation time by many orders of magnitude. When only Néel relaxation is present—if the particles are embedded in a solid for instance—the authors found that there can be a strong magnetization response to a sinusoidal driving field, even if the period is much less than the zero-field relaxation time. For a ferrofluid in which both Brownian and Néel relaxation are present, only one relaxation mechanism may dominate depending on the magnetic field strength, the driving frequency (or ramp time), and the phase of the magnetization relative to the

  20. Crater relaxation on Titan aided by low thermal conductivity sand infill

    Science.gov (United States)

    Schurmeier, Lauren R.; Dombard, Andrew J.

    2018-05-01

    Titan's few impact craters are currently many hundreds of meters shallower than the depths expected. Assuming these craters initially had depths equal to that of similar-size fresh craters on Ganymede and Callisto (moons of similar size, composition, and target lithology), then some process has shallowed them over time. Since nearly all of Titan's recognized craters are located within the arid equatorial sand seas of organic-rich dunes, where rain is infrequent, and atmospheric sedimentation is expected to be low, it has been suggested that aeolian infill plays a major role in shallowing the craters. Topographic relaxation at Titan's current heat flow was previously assumed to be an unimportant process on Titan due to its low surface temperature (94 K). However, our estimate of the thermal conductivity of Titan's organic-rich sand is remarkably low (0.025 W m-1 K-1), and when in thick deposits, will result in a thermal blanketing effect that can aid relaxation. Here, we simulate the relaxation of Titan's craters Afekan, Soi, and Sinlap including thermal effects of various amounts of sand inside and around Titan's craters. We find that the combination of aeolian infill and subsequent relaxation can produce the current crater depths in a geologically reasonable period of time using Titan's current heat flow. Instead of needing to fill completely the missing volume with 100% sand, only ∼62%, ∼71%, and ∼97%, of the volume need be sand at the current basal heat flux for Afekan, Soi, and Sinlap, respectively. We conclude that both processes are likely at work shallowing these craters, and this finding contributes to why Titan overall lacks impact craters in the arid equatorial regions.

  1. Changes in guava (Psidium guajava L. var. Paluma nectar volatile compounds concentration due to thermal processing and storage

    Directory of Open Access Journals (Sweden)

    Maria Ivaneide Coutinho Correa

    2010-12-01

    Full Text Available Guava nectars were formulated for approximately 10, 12, or 14 ºBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 ºC/42 seconds in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 ºC or refrigerated (5 ± 2 ºC under fluorescent light exposure and analyzed on the day after processing (time zero and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC -Mass Spectrometry (MS: hexanal, (E-hex-2-enal, 1-hexenol, (Z-hex-3-enol, (Z-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001 in hexanal and (Z-hex-3-enyl acetate (p = 0.0029. As for the storage time, there was a much greater decrease in the esters contents, such as (Z-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

  2. Losses of neutral injected fast ions due to adiabaticity breaking processes in a field-reversed configuration

    International Nuclear Information System (INIS)

    Takahashi, Toshiki; Inoue, Koji; Ishizuka, Takashi; Kondoh, Yoshiomi; Iwasawa, Naotaka

    2004-02-01

    Losses of neutral beam (NB) injected fast ions from the confinement region of a Field-Reversed Configuration (FRC) with a strong magnetic mirror are numerically analyzed for parameters relevant to NB injection experiments on the FIX (FRC injection experiment) device [T. Asai et al., Phys. Plasmas 7, 2294 (2000)]. Ionization processes of beam particles are calculated by the Monte Carlo method. The confinement of beam ions is discussed with the concept of accessible regions that restrict the ion excursion and are determined from two constants of motion, the kinetic energy and canonical angular momentum, in the case of an axisymmetric and a steady state FRC without an electrostatic field. From the calculation of the accessible regions, it is found that all the fast ions suffer from the orbit loss on the wall surface and/or the end loss. Single particle orbits are also calculated to find a difference of confinement properties from the results by employing the accessible regions. The magnetic moment is observed to show non-adiabatic motions of the beam ions, which cause a gradual orbit loss on the wall even in a case that a strong magnetic mirror is applied. The results show that the correlation of the magnetic moment disappears as the fast ions experience the density gradient around the separatrix surface and the field-null points. (author)

  3. Alterations in soil microbial activity and N-transformation processes due to sulfadiazine loads in pig-manure

    International Nuclear Information System (INIS)

    Kotzerke, Anja; Sharma, Shilpi; Schauss, Kristina; Heuer, Holger; Thiele-Bruhn, Soeren; Smalla, Kornelia; Wilke, Berndt-Michael; Schloter, Michael

    2008-01-01

    Most veterinary drugs enter the environment via manure application. However, it is unclear how these substances interact with soil biota. Therefore, it was the aim of the present study to investigate the effects of manure containing different concentrations of the antibiotic sulfadiazine (SDZ) on the soil microbial communities. It was shown that manure alone has a stimulating effect on microbial activity. Only potential nitrification was negatively influenced by manure application. The addition of SDZ to the manure reduced microbial activity. Depending on the SDZ concentration, levels of activity were in the range of the control soil without manure application. Also, selected processes in nitrogen turnover were negatively influenced by the addition of SDZ to the manure, with nitrification being the only exception. The effects were visible for up to 4 days after application of the manure with or without SDZ and were correlated with the bioavailability of the antibiotic. - This study gives first insights into the effects of manure containing the antibiotic sulfadiazine on microbial activity and nitrogen transformation potentials in soil

  4. Medial temporal lobe-dependent repetition suppression and enhancement due to implicit versus explicit processing of individual repeated search displays

    Directory of Open Access Journals (Sweden)

    Thomas eGeyer

    2012-10-01

    Full Text Available Using visual search, functional magnetic resonance imaging (fMRI and patient studies have demonstrated that medial temporal lobe (MTL structures differentiate repeated from novel displays – even when observers are unaware of display repetitions. This suggests a role for MTL in both explicit and, importantly, implicit learning of repeated sensory information (Greene et al., 2007. However, recent behavioral studies suggest, by examining visual search and recognition performance concurrently, that observers have explicit knowledge of at least some of the repeated displays (Geyer et al., 2010. The aim of the present fMRI study was thus to contribute new evidence regarding the contribution of MTL structures to explicit versus implicit learning in visual search. It was found that MTL activation was increased for explicit and, respectively, decreased for implicit relative to baseline displays. These activation differences were most pronounced in left anterior parahippocampal cortex, especially when observers were highly trained on the repeated displays. The data are taken to suggest that explicit and implicit memory processes are linked within MTL structures, but expressed via functionally separable mechanisms (repetition enhancement vs. -suppression. They further show that repetition effects in visual search would have to be investigated at the display level.

  5. Relaxation properties in classical diamagnetism

    Science.gov (United States)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  6. Onsager relaxation of toroidal plasmas

    International Nuclear Information System (INIS)

    Samain, A.; Nguyen, F.

    1997-01-01

    The slow relaxation of isolated toroidal plasmas towards their thermodynamical equilibrium is studied in an Onsager framework based on the entropy metric. The basic tool is a variational principle, equivalent to the kinetic equation, involving the profiles of density, temperature, electric potential, electric current. New minimization procedures are proposed to obtain entropy and entropy production rate functionals. (author)

  7. Anisotropic spin relaxation in graphene

    NARCIS (Netherlands)

    Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.

    2008-01-01

    Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular

  8. Stochastic and Chaotic Relaxation Oscillations

    NARCIS (Netherlands)

    Grasman, J.; Roerdink, J.B.T.M.

    1988-01-01

    For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

  9. Tensions relaxation in Zircaloy-4

    International Nuclear Information System (INIS)

    Cuniberti, A.M.; Picasso, A.C.

    1990-01-01

    Traction and stress relaxation studies were performed on polycrystalline Zry-4 at room temperature. The effect of loading velocity on the plastic behaviour of the material is discussed, analysing log σ vs. log dε/dt at different deformation levels. The contribution introduced by the testing machine was taken into account in data evaluation. (Author). 7 refs., 3 figs., 3 tabs

  10. Stress relaxation in 'aged high-purity aluminium at room temperature

    International Nuclear Information System (INIS)

    Butt, M.Z.; Haq, I.U.

    1993-01-01

    Stress relaxation in 99.996% Al polycrystals of average grain diameter 0.30, 0.42 and 0.51 mm, annealed at 500 deg. C and 'aged' for six months at room temperature, have been studied as a function of initial stress level from which relaxation at constant strain was allowed to start. The results obtained were compared with those for 'un-aged' Al specimens of the same purity and grain size. The intrinsic height of the thermally activable energy barrier (1.6 eV) evaluated for 'aged' Al is comparable with that (1.9 eV) for 'un-aged' Al, and is of the order of magnitude for recovery processes. In 'aged' specimens, the relaxation rate at a given stress level is larger and associated activation volume is smaller than that in 'un-aged' specimens. This is probably due to the diffusion of vacancies and/or residual impurity atoms to the cores to edge dislocations in 'aged' specimens; the length of dislocation segment involved in unit activation process therefore gets shortened compared with that in 'un-aged' specimens. (author)

  11. Ultra-fast relaxation kinetics in semiconductors

    International Nuclear Information System (INIS)

    Luzzi, R.

    1983-01-01

    It is presented a brief description of relaxation processes in highly excited semiconductor plasmas (HESP). Comparison with experimental data obtained by means of ultra-fast laser light spectroscopy (UFLS) is made. Some aspects of response funtion theory in systems far-from-equilibrium are reviewed in Section II. In Section III we present some comments on the question of nonequilibrium thermodynamics relevant to the problem to be considered. In last section we present a brief summary of the different aspects of the subject. (author) [pt

  12. Charge imbalance: its relaxation, diffusion and oscillation

    International Nuclear Information System (INIS)

    Pethick, C.J.

    1981-01-01

    In this article, the authors use a model for charge density based on two charge components: the normal quasiparticle component and the superfluid/condensate component. Based on the quasiparticle Boltzmann equation, this two-component model, when used in nonequilibrium contexts, is fruitful in describing a variety of charge-imbalance phenomena in superconductors. The authors discuss various methods of generating charge-imbalances, charge-imbalance relaxation processes (such as phonons, impurity scattering and magnetic impurities) and applications of the two-component model of charge imbalance to spatially inhomogeneous conditions

  13. Ultra-fast relaxation kinetics in semiconductors

    International Nuclear Information System (INIS)

    Luzzi, R.

    1983-01-01

    It is presented a brief description of relaxation processes in highly excited semiconductor plasmas (HESP). Comparison with experimental data obtained by means of ultra-fast laser light spectroscopy (UFLS) is made. Some aspects of response function theory in systems far-from-equilibrium are reviewed in Section II. In Section III some comments on the question of nonequilibrium thermodynamics relevant to the problem to be considered are presented. In last Section a brief summary of the different aspects of the subject is also presented. (Author) [pt

  14. Pollution Status of Trace Metals in Groundwater Due to Industrail Activities in and Around Dhaka Export Processing Zone, Bangladesh

    Directory of Open Access Journals (Sweden)

    GOLAM AHMED

    2012-06-01

    Full Text Available Effluents from multiindustrail activities influence inland water system directly, which subsiquently affect groundwater quality and human health. Some previous reports indicated that inadequate treatment process of discharged effluent of Dhaka Export Processing Zone (DEPZ increased the concentrations of pollutants in surface water system and deteriorated total fishing and agricultural system around DEPZ and its connected area. Therefore, the present study was conducted to investigate wether the concentration of selective metals viz. Li, V, Cr, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and U in two types of groundwater sources were either with in the permissible guidlines or influenced by DEPZ multi industrail on their levels of contamination. The concentrations of metals were determined using inductively Couples Plasma Mass Spectrometry (ICP-MS. The mean concentrations of the elements in both types of groundwater were in the levels of their permissible guidlines, except for Ni (12.91 µg/L, Ga (0.48µg/L, Sr (90.26 µg/L and Cs (0.07µg//Lin groundwater inside DEPZ, which were 1.30, 5.00, 1.50 and 1.40 times higher than the maximum permissible limit (MPL of 10 µg/L, 0.09 µg/L, 60 µg/L, and 0.05µg/L, respectively. The mean concentrations of Li (6.85 µg/L, Zn(268 µg/L, Ga (0.12 µg/L, Sr (131 µg/L and Cs (0.07 µg/L were 3.43, 1.34, 1.33, 2.18, 1.40 times higher then the MPL of 2 µg/L, 200 µg/L, 0.09 µg/L, 60 µg/L and 0.05 µg/L, respectively, in groundwater around DEPZ. Comparatively Zn and Sr possessed higher concentrations, and Cs and U possessed lower concentration in both types of groundwater sources. The elements were distributed in homogeneous and hetrogeneous manner among the source points for deep-tubewell (DTWS and shallow tubewell (STWs, respectively. The significant positive correlations were found between the elements viz., Co-V (0.85, Ni-Sr ((0.70, Co-Cd (0.86, As-Se (0.99, Cs-Zn (0.95, Li-U (0.,71, Zn-U (0

  15. Low-level laser therapy (LLLT) accelerates the sternomastoid muscle regeneration process after myonecrosis due to bupivacaine.

    Science.gov (United States)

    Alessi Pissulin, Cristiane Neves; Henrique Fernandes, Ana Angélica; Sanchez Orellana, Alejandro Manuel; Rossi E Silva, Renata Calciolari; Michelin Matheus, Selma Maria

    2017-03-01

    Because of its long-lasting analgesic action, bupivacaine is an anesthetic used for peripheral nerve block and relief of postoperative pain. Muscle degeneration and neurotoxicity are its main limitations. There is strong evidence that low-level laser therapy (LLLT) assists in muscle and nerve repair. The authors evaluated the effects of a Gallium Arsenide laser (GaAs), on the regeneration of muscle fibers of the sternomastoid muscle and accessory nerve after injection of bupivacaine. In total, 30 Wistar adult rats were divided into 2 groups: control group (C: n=15) and laser group (L: n=15). The groups were subdivided by antimere, with 0.5% bupivacaine injected on the right and 0.9% sodium chloride on the left. LLLT (GaAs 904nm, 0,05W, 2.8J per point) was administered for 5 consecutive days, starting 24h after injection of the solutions. Seven days after the trial period, blood samples were collected for determination of creatine kinase (CK). The sternomastoid nerve was removed for morphological and morphometric analyses; the surface portion of the sternomastoid muscle was used for histopathological and ultrastructural analyses. Muscle CK and TNFα protein levels were measured. The anesthetic promoted myonecrosis and increased muscle CK without neurotoxic effects. The LLLT reduced myonecrosis, characterized by a decrease in muscle CK levels, inflammation, necrosis, and atrophy, as well as the number of central nuclei in the muscle fibers and the percentage of collagen. TNFα values remained constant. LLLT, at the dose used, reduced fibrosis and myonecrosis in the sternomastoid muscle triggered by bupivacaine, accelerating the muscle regeneration process. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. F19 relaxation in non-magnetic hexafluorides

    International Nuclear Information System (INIS)

    Rigny, P.

    1969-01-01

    The interesting properties of the fluorine magnetic resonance in the hexafluorides of molybdenum, tungsten and uranium, are very much due to large anisotropies of the chemical shift tensors. In the solid phases these anisotropies, the values of which are deduced from line shape studies, allow one to show that the molecules undergo hindered rotations about the metal atom. The temperature and frequency dependence of the fluorine longitudinal relaxation times shows that the relaxation is due to the molecular motion. The dynamical parameters of this motion are then deduced from the complete study of the fluorine relaxation in the rotating frame. In the liquid phases, the existence of anisotropies allows an estimation of the different contributions to the relaxation. In particular, the frequency and temperature dependence of the relaxation shows it to be dominated by the spin-rotation interaction. We have shown that the strength of this interaction can be deduced from the chemical shifts, and the angle through which the molecule rotates quasi-freely can be determined. In the hexafluorides, this angle is roughly one radian at 70 C, and with the help of this value, the friction coefficients which describe the intermolecular interactions are discussed. (author) [fr

  17. Sleep, Stress & Relaxation: Rejuvenate Body & Mind

    Science.gov (United States)

    Sleep, Stress & Relaxation: Rejuvenate Body & Mind; Relieve Stress; best ways to relieve stress; best way to relieve stress; different ways to relieve stress; does smoking relieve stress; does tobacco relieve stress; how can I relieve stress; how can you relieve stress; how do I relieve stress; reduce stress; does smoking reduce stress; how can I reduce stress; how to reduce stress; reduce stress; reduce stress levels; reducing stress; smoking reduce stress; smoking reduces stress; stress reducing techniques; techniques to reduce stress; stress relief; best stress relief; natural stress relief; need stress relief; relief for stress; relief from stress; relief of stress; smoking and stress relief; smoking for stress relief; smoking stress relief; deal with stress; dealing with stress; dealing with anger; dealing with stress; different ways of dealing with stress; help dealing with stress; how to deal with anger; how to deal with stress; how to deal with stress when quitting smoking; stress management; free stress management; how can you manage stress; how do you manage stress; how to manage stress; manage stress; management of stress; management stress; managing stress; strategies for managing stress; coping with stress; cope with stress; copeing with stress; coping and stress; coping skills for stress; coping strategies for stress; coping strategies with stress; coping strategy for stress; coping with stress; coping with stress and anxiety; emotional health; emotional health; emotional health article; emotional health articles; deep relaxation; deep breathing relaxation techniques; deep muscle relaxation; deep relaxation; deep relaxation meditation; deep relaxation technique; deep relaxation techniques; meditation exercises; mindful exercises; mindful meditation exercises; online relaxation exercises; relaxation breathing exercises; relaxation exercise; relaxation exercises; stress relaxation; methods of relaxation for stress; relax stress; relax techniques stress

  18. Relaxation of energetic S(1D) atoms in Xe gas: comparison of ab initio calculations with experimental data.

    Science.gov (United States)

    Bovino, S; Zhang, P; Kharchenko, V; Dalgarno, A

    2011-07-14

    In this paper, we report our investigation of the translational energy relaxation of fast S((1)D) atoms in a Xe thermal bath. The interaction potential of Xe-S was constructed using ab initio methods. Total and differential cross sections were then calculated. The latter have been incorporated into the construction of the kernel of the Boltzmann equation describing the energy relaxation process. The solution of the Boltzmann equation was obtained and results were compared with those reported in experiments [G. Nan, and P. L. Houston, J. Chem. Phys. 97, 7865 (1992)]. Good agreement with the measured time-dependent relative velocity of fast S((1)D) atoms was obtained except at long relaxation times. The discrepancy may be due to the error accumulation caused by the use of hard sphere approximation and the Monte Carlo analysis of the experimental data. Our accurate description of the energy relaxation process led to an increase in the number of collisions required to achieve equilibrium by an order of magnitude compared to the number given by the hard-sphere approximation.

  19. Nonequilibrium thermodynamics and information theory: basic concepts and relaxing dynamics

    International Nuclear Information System (INIS)

    Altaner, Bernhard

    2017-01-01

    Thermodynamics is based on the notions of energy and entropy. While energy is the elementary quantity governing physical dynamics, entropy is the fundamental concept in information theory. In this work, starting from first principles, we give a detailed didactic account on the relations between energy and entropy and thus physics and information theory. We show that thermodynamic process inequalities, like the second law, are equivalent to the requirement that an effective description for physical dynamics is strongly relaxing. From the perspective of information theory, strongly relaxing dynamics govern the irreversible convergence of a statistical ensemble towards the maximally non-commital probability distribution that is compatible with thermodynamic equilibrium parameters. In particular, Markov processes that converge to a thermodynamic equilibrium state are strongly relaxing. Our framework generalizes previous results to arbitrary open and driven systems, yielding novel thermodynamic bounds for idealized and real processes. (paper)

  20. Real-Time Observation of Ultrafast Intraband Relaxation and Exciton Multiplication in PbS Quantum Dots

    KAUST Repository

    El-Ballouli, Ala’a O.

    2014-03-19

    We examine ultrafast intraconduction band relaxation and multiple-exciton generation (MEG) in PbS quantum dots (QDs) using transient absorption spectroscopy with 120 fs temporal resolution. The intraconduction band relaxation can be directly and excellently resolved spectrally and temporally by applying broadband pump-probe spectroscopy to excite and detect the wavelengths around the exciton absorption peak, which is located in the near-infrared region. The time-resolved data unambiguously demonstrate that the intraband relaxation time progressively increases as the pump-photon energy increases. Moreover, the relaxation time becomes much shorter as the size of the QDs decreases, indicating the crucial role of spatial confinement in the intraband relaxation process. Additionally, our results reveal the systematic scaling of the intraband relaxation time with both excess energy above the effective energy band gap and QD size. We also assess MEG in different sizes of the QDs. Under the condition of high-energy photon excitation, which is well above the MEG energy threshold, ultrafast bleach recovery due to the nonradiative Auger recombination of the multiple electron-hole pairs provides conclusive experimental evidence for the presence of MEG. For instance, we achieved quantum efficiencies of 159, 129 and 106% per single-absorbed photon at pump photoexcition of three times the band gap for QDs with band gaps of 880 nm (1.41 eV), 1000 nm (1.24 eV) and 1210 nm (1.0 eV), respectively. These findings demonstrate clearly that the efficiency of transferring excess photon energy to carrier multiplication is significantly increased in smaller QDs compared with larger ones. Finally, we discuss the Auger recombination dynamics of the multiple electron-hole pairs as a function of QD size.

  1. Comparing the influence of relaxation training and consumption of ...

    African Journals Online (AJOL)

    Background: Sleep disturbance is one of the symptoms of menopause, which occurs due to a decrease in sex hormones and dramatically affects the quality of life. This study was designed to compare the effects of relaxation and Valerian on insomnia of menopause women. Methods: The study was a randomized clinical ...

  2. Giant dipole resonances in hot nuclear matter in the model of self-relaxing mean field

    International Nuclear Information System (INIS)

    Okolowicz, J.; Ploszajczak, M.; Drozdz, S.; Caurier, E.

    1989-01-01

    The extended time-dependent Hartree-Fock approach is applied for the description of the isovector giant dipole resonance in 40 Ca at finite temperatures. The thermalization process is described using the relaxation-time ansatz for the collision integral. Strong inhibition of the giant-dipole-resonance γ-decay is found due to the fast vaporization of the nuclear surface for thermal excitation energies above E * /A ≅ 4.5 MeV. This pre-equilibrium emission of particles in the vapor phase is associated with the radial expansion of nucleus and with the vanishing particle binding energies mainly for protons. (orig.)

  3. Effect of carrier relaxation lifetime on the performance of InAs/InP quantum-dash lasers

    KAUST Repository

    Khan, Mohammed Zahed Mustafa

    2011-12-01

    The effect of carrier relaxation process into the quantum dash (Qdash) ground state (GS) is examined theoretically by carrier-photon rate equation model incorporating the inhomogeneous broadening. Increase in the relaxation time and the inhomogeneous broadening degrades the threshold current density. Moreover, our results show that a relaxation time of less than 2 ps gives optimum laser performance. © 2011 IEEE.

  4. Differential multiple quantum relaxation caused by chemical exchange outside the fast exchange limit

    International Nuclear Information System (INIS)

    Wang Chunyu; Palmer, Arthur G.

    2002-01-01

    Differential relaxation of multiple quantum coherences is a signature for chemical exchange processes in proteins. Previous analyses of experimental data have used theoretical descriptions applicable only in the limit of fast exchange. Theoretical expressions for differential relaxation rate constants that are accurate outside fast exchange are presented for two-spin-system subject to two-site chemical exchange. The theoretical expressions are validated using experimental results for 15 N- 1 H relaxation in basic pancreatic trypsin inhibitor. The new theoretical expression is valuable for identification and characterization of exchange processes in proteins using differential relaxation of multiple quantum coherences

  5. Vibrational-rotational relaxation of the simplest hydrogen-containing molecules (review)

    International Nuclear Information System (INIS)

    Molevich, N.E.; Oraevskii, A.N.

    1987-01-01

    In connection with the development of chemical lasers much attention is now devoted to the study of kinetic processes is gaseous mixtures containing the hydrogen halides. Vibrational relaxation of molecules if primarily studied without specifying its relation to the rational levels. Rotational relaxation is regarded a priori as faster than vibrational relaxation, so that the population of the rotational levels is assumed to be in equilibrium. This approach to the relaxation of hydrogen halide molecules (and other diatomic hydrogen-containing molecules), however, is unable to explain satisfactorily the results of the papers discussed below. An analysis of the data obtained in these papers leads to the conclusion that the general picture of relaxation in diatomic hydrogen-containing molecules must be viewed as a unified process of vibrational and rotational relaxation. It is shown that those effects observed during vibrational relaxation of such molecules which are unusual from the standpoint of the theory of vibrational-translational relaxation are well explained in terms of intermolecular vibrational-rotational relaxation together with pure rotational relaxation

  6. Dynamic and structural characterisation of micellar solutions of surfactants by spin relaxation and translational diffusion

    International Nuclear Information System (INIS)

    Mahieu, Nathalie

    1992-01-01

    The work reported in this research thesis aimed at characterizing micellar phases formed by some surfactants (sodium carboxylates) in aqueous solution. After some recalls on nuclear magnetic resonance dealing with spin relaxation (longitudinal relaxation, transverse relaxation, relaxation in the rotating coordinate system, and crossed relaxation), and comments on the dipolar mechanism responsible of relaxation phenomena, the author presents the methods used for relaxation parameter measurement and the data processing software issued from experiments. He presents experiments which allowed the self-diffusion coefficient to be measured, reports data processing, and addresses problems of special diffusion and of coherence transfers during diffusion measurements. Results of proton relaxation measurements are then presented and discussed. They are used to determine the micellar state of the studied carboxylates. The case of the oleate is also addressed. Measurements of carbon-13 relaxation times are reported, and exploited in terms of structural parameters by using the Relaxator software. An original method of the hetero-nuclear Overhauser method is presented, and used to assess the average distance between water molecules and micelle surface [fr

  7. Relaxation Techniques to Manage IBS Symptoms

    Science.gov (United States)

    ... for 15–20 seconds and then begin again. Progressive Muscle Relaxation This method of relaxation focuses on ... helpful, please consider supporting IFFGD with a small tax- deductible donation. Make Donation Adapted from IFFGD Publication # ...

  8. Relaxation and Distraction in Experimental Desensitization.

    Science.gov (United States)

    Weir, R. O.; Marshall, W. L.

    1980-01-01

    Compared experimental desensitization with a procedure that replaced relaxation with a distraction task and with an approach that combined both relaxation and distraction. Desensitization generally was more effective than the other two procedures. (Author)

  9. Relaxation as a Factor in Semantic Desensitization

    Science.gov (United States)

    Bechtel, James E.; McNamara, J. Regis

    1975-01-01

    Relaxation and semantic desensitization were used to alleviate the fear of phobic females. Results showed that semantic desensitization, alone or in combination with relaxation, failed to modify the evaluative meanings evoked by the feared object. (SE)

  10. Effect of reorientation of anisotropic point defects on relaxation of crystal elastic coefficients of high order

    International Nuclear Information System (INIS)

    Topchyan, I.I.; Dokhner, R.D.

    1977-01-01

    The effect of reorientation of anisotropic point defects in uniform fields of elastic stresses on the relaxation of the elastic coefficients of a crystal was investigated in the nonlinear elasticity theory approximation. In calculating the interaction of point defects with elastic-stress fields was taken into consideration. The expression for the relaxations of the elasticity coefficients are obtained in an analytical form. The relaxation of the second-order elasticity coefficients is due to the dimentional interaction of a point defect with an applied-stress field, whereas the relaxation of the higher-order elasticity coefficients is determined both by dimentional and module effects

  11. Due diligence

    International Nuclear Information System (INIS)

    Sanghera, G.S.

    1999-01-01

    The Occupational Health and Safety (OHS) Act requires that every employer shall ensure the health and safety of workers in the workplace. Issues regarding the practices at workplaces and how they should reflect the standards of due diligence were discussed. Due diligence was described as being the need for employers to identify hazards in the workplace and to take active steps to prevent workers from potentially dangerous incidents. The paper discussed various aspects of due diligence including policy, training, procedures, measurement and enforcement. The consequences of contravening the OHS Act were also described

  12. Effect of magnetic field on charge imbalance relaxation of non-equilibrium superconductivity

    International Nuclear Information System (INIS)

    Tsuboi, Kazuki; Yagi, Ryuta

    2010-01-01

    We have studied relaxation of charge imbalance of non-equilibrium superconductivity in magnetic field. We found that excess current due to charge imbalance showed striking dependence on magnitude of magnetic field and its orientation. We discussed origin of the relaxation.

  13. Relaxation of Shot-Peened Residual Stresses Under Creep Loading (Preprint)

    Science.gov (United States)

    2008-10-01

    Residual Stresses,” SAE Technical Paper No. 710285, SAE , 1971. [8] Hoffman, J., Scholtes, B., Vöhringer, O., and Macherauch, E., “Thermal relaxation of...relaxation in an AISI 4140 steel due to quasistatic and cyclic loading at higher temperatures,” Material Science and Engineering A248, 1998, pp. 9

  14. Vibronic relaxation in molecular mixed crystals : Pentacene in naphthalene and p-terphenyl

    NARCIS (Netherlands)

    Hesselink, Wim H.; Wiersma, Douwe A.

    1981-01-01

    Picosecond photon echo techniques are used to measure directly vibronic relaxation times in the first excited singlet state of pentacene in naphthalene and p-terphenyl. In regions of low (< 300 cm–1) and high (> 1000 cm–1) vibrational energy, relaxation is fast (τ <2 ps) due to direct phonon

  15. Novel spin dynamics in ferrimagnetic molecular chains from 1H NMR and μSR spin-lattice relaxation measurements

    International Nuclear Information System (INIS)

    Micotti, E.; Lascialfari, A.; Rigamonti, A.; Aldrovandi, S.; Caneschi, A.; Gatteschi, D.; Bogani, L.

    2004-01-01

    The spin dynamics in the helical chain Co(hfac) 2 NITPhOMe has been investigated by 1 H NMR and μSR relaxation. In the temperature range 15< T<60 K, the results are consistent with the relaxation of the homogeneous magnetization. For T≤15 K, NMR and μSR evidence a second spin relaxation mechanism, undetected by the magnetization measurements. From the analysis of these data, insights on this novel relaxation process are derived

  16. Novel spin dynamics in ferrimagnetic molecular chains from 1H NMR and μSR spin-lattice relaxation measurements

    Science.gov (United States)

    Micotti, E.; Lascialfari, A.; Rigamonti, A.; Aldrovandi, S.; Caneschi, A.; Gatteschi, D.; Bogani, L.

    2004-05-01

    The spin dynamics in the helical chain Co(hfac) 2NITPhOMe has been investigated by 1H NMR and μSR relaxation. In the temperature range 15relaxation of the homogeneous magnetization. For T⩽15 K, NMR and μSR evidence a second spin relaxation mechanism, undetected by the magnetization measurements. From the analysis of these data, insights on this novel relaxation process are derived.

  17. Nuclear quadrupole relaxation and viscosity in liquid metals

    International Nuclear Information System (INIS)

    Schirmacher, W.

    1976-01-01

    It is shown that the nuclear quadrupole relaxation rate due to the molecular motions in liquid metals is related to the shear and bulk viscosity and hence to the absorption coefficient of ultrasound. Application of the 'extended liquid phonon' model of Ortoleva and Nelkin - which is the third of a series of continued-fraction-approximations for the van Hove neutron scattering function - gives a relation to the self diffusion constant. The predictions of the theory concerning the temperature dependence are compared with quadrupole relaxation measurements of Riegel et al. and Kerlin et al. in liquid gallium. Agreement is found only with the data of Riegel et al. (orig.) [de

  18. Fast relaxation transients in a kicked damped oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Urquizu, Merce [Laboratori d' Estudis Geofisics ' Eduard Fontsere' , IEC, Barcelona (Spain); Correig, Antoni M. [Departament d' Astronomical i Meteorologia, Laboratori d' Estudis Geofisics Eduard Fontsere, UB Marti Franques 1, E-08028 Barcelona (Spain) and Laboratori d' Estudis Geofisics ' Eduard Fontsere' , IEC, Barcelona (Spain)]. E-mail: ton.correig@am.ub.es

    2007-08-15

    Although nonlinear relaxation transients are very common in nature, very few studies are devoted to its characterization, mainly due to its short time duration. In this paper, we present a study about the nature of relaxation transients in a kicked damped oscillator, in which transients are generated in terms of continuous fast changes in the parameters of the system. We have found that transient dynamics can be described, rather than in terms of bifurcation dynamics, in terms of instantaneous stretching factors, which are related to the stability of fixed points of the corresponding stroboscopic maps.

  19. Dispersion of Sound in Dilute Suspensions with Nonlinear Particle Relaxation

    Science.gov (United States)

    Kandula, Max

    2010-01-01

    The theory accounting for nonlinear particle relaxation (viscous and thermal) has been applied to the prediction of dispersion of sound in dilute suspensions. The results suggest that significant deviations exist for sound dispersion between the linear and nonlinear theories at large values of Omega(Tau)(sub d), where Omega is the circular frequency, and Tau(sub d) is the Stokesian particle relaxation time. It is revealed that the nonlinear effect on the dispersion coefficient due to viscous contribution is larger relative to that of thermal conduction

  20. Field dependence of the electron spin relaxation in quantum dots.

    Science.gov (United States)

    Calero, Carlos; Chudnovsky, E M; Garanin, D A

    2005-10-14

    The interaction of the electron spin with local elastic twists due to transverse phonons is studied. The universal dependence of the spin-relaxation rate on the strength and direction of the magnetic field is obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid. The theory contains no unknown parameters and it can be easily tested in experiment. At high magnetic field it provides a parameter-free lower bound on the electron spin relaxation in quantum dots.

  1. Relaxation of nuclear spin on holes in semiconductors

    International Nuclear Information System (INIS)

    Gr'ncharova, E.I.; Perel', V.I.

    1977-01-01

    The longitudienal relaxation time T 1 of nuclear spins due to dipole-dipole interaction with holes in semiconductors is calculated. Expressions for T 1 in cubic and uniaxial semiconductors are obtained for non-degenerate and degenerate cases. On the basis of comparison with available experimental data for silicon the agreement with the theoretical results is obtained. It is demonstrated that in uniaxial semiconductors the time of relaxation on holes for a nuclear spin directed along the c axis is considerably greater than that for a spin in the normal direction

  2. Plasmon-mediated energy relaxation in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, D. K. [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Somphonsane, R. [Department of Physics, King Mongkut' s Institute of Technology, Ladkrabang, Bangkok 10520 (Thailand); Ramamoorthy, H.; Bird, J. P. [Department of Electrical Engineering, University at Buffalo, the State University of New York, Buffalo, New York 14260-1500 (United States)

    2015-12-28

    Energy relaxation of hot carriers in graphene is studied at low temperatures, where the loss rate may differ significantly from that predicted for electron-phonon interactions. We show here that plasmons, important in the relaxation of energetic carriers in bulk semiconductors, can also provide a pathway for energy relaxation in transport experiments in graphene. We obtain a total loss rate to plasmons that results in energy relaxation times whose dependence on temperature and density closely matches that found experimentally.

  3. Nonlinear Relaxation in Population Dynamics

    Science.gov (United States)

    Cirone, Markus A.; de Pasquale, Ferdinando; Spagnolo, Bernardo

    We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the ith population and on the distribution of the population and of the local field.

  4. Structural relaxation: low temperature properties

    International Nuclear Information System (INIS)

    Cruz, F. de la

    1984-01-01

    We discuss the changes in transport and superconducting properties of amorphous Zr 70 Cu 30 , induced by thermal relaxation. The experimental results are used to investigate the relation between the microscopic parameters and the observed physical properties. It is shown that the density of eletronic states determines the shift Tc as well as the variation of the electrical resistivity. It is necessary to assume strong hybridization between s and d bands to understand the eletrodynamic response of the superconductor. (Author) [pt

  5. The Effects of Suggestibility on Relaxation.

    Science.gov (United States)

    Rickard, Henry C.; And Others

    1985-01-01

    Selected undergraduates (N=32) on the basis of Creative Imagination Scale scores and randomly assigned high and low suggestibility subjects to progressive relaxation (PR) and suggestions of relaxation (SR) training modes. Results revealed a significant pre-post relaxation effect, and main efffects for both suggestibility and training mode. (NRB)

  6. Relaxed Poisson cure rate models.

    Science.gov (United States)

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Vibrational relaxation in OCS mixtures

    International Nuclear Information System (INIS)

    Simpson, C.J.S.M.; Gait, P.D.; Simmie, J.M.

    1976-01-01

    Experimental measurements are reported of vibrational relaxation times which may be used to show whether there is near resonant vibration-rotation energy transfer between OCS and H 2 , D 2 or HD. Vibrational relaxation times have been measured in OCS and OCS mixtures over the temperature range 360 to 1000 K using a shock tube and a laser schlieren system. The effectiveness of the additives in reducing the relaxation time of OCS is in the order 4 He 3 He 2 2 and HD. Along this series the effect of an increase in temperature changes from the case of speeding up the rate with 4 He to retarding it with D 2 , HD and H 2 . There is no measurable difference in the effectiveness of n-D 2 and o-D 2 and little, or no, difference between n-H 2 and p-H 2 . Thus the experimental results do not give clear evidence for rotational-vibration energy transfer between hydrogen and OCS. This contrasts with the situation for CO 2 + H 2 mixtures. (author)

  8. Relaxed plasma-vacuum systems

    International Nuclear Information System (INIS)

    Spies, G.O.; Lortz, D.; Kaiser, R.

    2001-01-01

    Taylor's theory of relaxed toroidal plasmas (states of lowest energy with fixed total magnetic helicity) is extended to include a vacuum between the plasma and the wall. In the extended variational problem, one prescribes, in addition to the helicity and the magnetic fluxes whose conservation follows from the perfect conductivity of the wall, the fluxes whose conservation follows from the assumption that the plasma-vacuum interface is also perfectly conducting (if the wall is a magnetic surface, then one has the toroidal and the poloidal flux in the vacuum). Vanishing of the first energy variation implies a pressureless free-boundary magnetohydrostatic equilibrium with a Beltrami magnetic field in the plasma, and in general with a surface current in the interface. Positivity of the second variation implies that the equilibrium is stable according to ideal magnetohydrodynamics, that it is a relaxed state according to Taylor's theory if the interface is replaced by a wall, and that the surface current is nonzero (at least if there are no closed magnetic field lines in the interface). The plane slab, with suitable boundary conditions to simulate a genuine torus, is investigated in detail. The relaxed state has the same double symmetry as the vessel if, and only if, the prescribed helicity is in an interval that depends on the prescribed fluxes. This interval is determined in the limit of a thin slab

  9. Regularized Label Relaxation Linear Regression.

    Science.gov (United States)

    Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

    2018-04-01

    Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

  10. High-field transport of electrons and radiative effects using coupled force-balance and Fokker-Planck equations beyond the relaxation-time approximation

    International Nuclear Information System (INIS)

    Huang, Danhong; Apostolova, T.; Alsing, P.M.; Cardimona, D.A.

    2004-01-01

    The dynamics of a many-electron system under both dc and infrared fields is separated into a center-of-mass and a relative motion. The first-order force-balance equation is employed for the slow center-of-mass motion of electrons, and the Fokker-Planck equation is used for the ultrafast relative scattering motion of degenerate electrons. This approach allows us to include the anisotropic energy-relaxation process which has been neglected in the energy-balance equation in the past. It also leads us to include the anisotropic coupling to the incident infrared field with different polarizations. Based on this model, the transport of electrons is explored under strong dc and infrared fields by going beyond the relaxation-time approximation. The anisotropic dependence of the electron distribution function on the parallel and perpendicular kinetic energies of electrons is displayed with respect to the dc field direction, and the effect of anisotropic coupling to an incident infrared field with polarizations parallel and perpendicular to the applied dc electric field is shown. The heating of electrons is more accurately described beyond the energy-balance equation with the inclusion of an anisotropic coupling to the infrared field. The drift velocity of electrons is found to increase with the amplitude of the infrared field due to a suppressed momentum-relaxation process (or frictional force) under parallel polarization but decreases with the amplitude due to an enhanced momentum-relaxation process under perpendicular polarization

  11. From plastic to elastic stress relaxation in highly mismatched SiGe/Si heterostructures

    International Nuclear Information System (INIS)

    Isa, Fabio; Salvalaglio, Marco; Dasilva, Yadira Arroyo Rojas; Jung, Arik; Isella, Giovanni; Erni, Rolf; Niedermann, Philippe; Gröning, Pierangelo; Montalenti, Francesco; Känel, Hans von

    2016-01-01

    We present a detailed experimental and theoretical analysis of the epitaxial stress relaxation process in micro-structured compositionally graded alloys. We focus on the pivotal SiGe/Si(001) system employing patterned Si substrates at the micrometre-size scale to address the distribution of threading and misfit dislocations within the heterostructures. SiGe alloys with linearly increasing Ge content were deposited by low energy plasma enhanced chemical vapour deposition resulting in isolated, tens of micrometre tall 3D crystals. We demonstrate that complete elastic relaxation is achieved by appropriate choice of the Ge compositional grading rate and Si pillar width. We investigate the nature and distribution of dislocations along the [001] growth direction in SiGe crystals by transmission electron microscopy, chemical defect etching and etch pit counting. We show that for 3 μm wide Si pillars and a Ge grading rate of 1.5% μm −1 , only misfit dislocations are present while their fraction is reduced for higher Ge grading rates and larger structures due to dislocation interactions. The experimental results are interpreted with the help of theoretical calculations based on linear elasticity theory describing the competition between purely elastic and plastic stress relaxation with increasing crystal width and Ge compositional grading rate.

  12. Mechanical relaxation in chalcogenide glasses of the Ge-As-S system

    International Nuclear Information System (INIS)

    Bilanych, V.S.; Melnychenko, T.D.; Rizak, V.M.; Makauz, I.I.

    2006-01-01

    The temperature and frequency-related dependences of the internal friction and the shear modulus in Ge x As 40-x S 60 glasses have been studied. The maxima of internal friction of both the relaxation and non relaxation types have been found in the low-temperature range. A relaxation maximum has been revealed in the vitrification region, and its parameters have been determined. Possible mechanisms of these processes have been discussed

  13. Effects of thermal relaxation on an amorphous superconducting Zr--Rh alloy

    International Nuclear Information System (INIS)

    Drehman, A.J.; Johnson, W.L.

    1978-05-01

    The electronic and superconducting properties of an amorphous transition metal alloy are used to evaluate the effects of low temperature annealing. It is observed that the superconducting transition temperature and the electrical resistivity relax exponentially in time from their initial value to a final relaxed value. From this an activation energy for the relaxation process is derived and an explanation is suggested which involves internal stress

  14. Effect of iodine impurity on relaxation of photoexcited silver chloride

    International Nuclear Information System (INIS)

    Vostrikova, Yu. V.; Klyuev, V. G.

    2008-01-01

    The time and temperature dependences of relaxation of excited AgCl and AgCl:I crystals is studied by the method of photostimulated flash of luminescence. The presence of iodine impurity in silver chloride gives rise to hole recombination (luminescence) centers and hole traps in the band gap. It is shown that the main contribution to the decrease in the concentration of electrons localized at deep traps is made by the recombination of electrons with holes released thermally from shallow localization levels (iodine-related centers). Estimation of activation energy for the relaxation process showed that these energies for the AgCl and AgCl:I samples under study are the same within the experimental error and are equal to E rel1 = 0.01 ± 0.0005 eV for the initial stage of relaxation and E rel2 = 0.09 ± 0.005 eV for the final state. This fact indicates that the majority of hole traps involved in the relaxation process in AgCl are related to iodine impurity. In the course of thermal relaxation in AgCl, relocalization of nonequilibrium charge carriers from shallow levels to deep levels is observed. The depth of the corresponding trap is E arl = 0.174 ± 0.03 eV.

  15. Transverse magnetic field effects on the relaxation time of the magnetization in Mn12 measured by 55Mn-NMR

    International Nuclear Information System (INIS)

    Furukawa, Y.; Watanabe, K.; Kumagai, K.; Borsa, F.; Gatteschi, D.

    2003-01-01

    The longitudinal (H Z ) and transverse (H T ) magnetic field dependence of the relaxation time of the magnetization in Mn12 in its S=10 ground state was measured by NMR. The minima in the relaxation time at the fields for level crossing are due to the quantum tunneling of the magnetization. The shortening of the relaxation time under the application of H T is shown to be due mainly to the reduction of the energy barrier

  16. Relaxation oscillations in stimulated Raman scattering

    International Nuclear Information System (INIS)

    Kachen, G.I.; Lowdermilk, W.H.

    1977-01-01

    Light pulses created by stimulated Raman scattering having been found to exhibit a complex time dependence which resembles relaxation oscillations. A focused laser pulse generated both forward and backward Raman emissions which appeared as a series of pulses with durations much shorter than the incident laser pulse. Time dependence of the Raman emission was observed directly by use of a streak camera. The number of observed pulses increased with the intensity of the incident pulse, while separation of the pulses in time depended on the length of the focal region. Beam focusing was incorporated in the coupled wave equations for stimulated Raman scattering. These rate equations were then solved numerically, and the results are in good qualitative agreement with the experimental observations. The short Raman pulses are created by a process associated with depletion of the incident laser pulse. This process occurs under a broad range of conditions

  17. Dynamics and relaxation in confined medium. Application to 129Xe magnetic relaxation in Vycor

    International Nuclear Information System (INIS)

    Pasquier, Virginie

    1995-01-01

    Porous media morphology and topology drive the exploration of pore space by fluid. So, analysis of transport process, associated with relaxation mechanism, allows indirect study of pore geometry. The purpose of this work is to understand better the relation between geometry and transport. This study involves two parts: a modelization and prediction step is followed by an experimental application of magnetic relaxation. Numerical simulations and analytical models allow to quantify the influence on the solid interface of the dynamical behavior of confined gas in disordered porous media (granular structure and porous network) or in common geometry (cylindrical and lamellar interfaces). The formalism of diffusion propagator is a powerful tool to quantify the influence of the pore geometry on the diffusion of confined gas. The propagator holds all dynamical information on the system; it also predicts the temporal evolution of the autocorrelation functions of the Hamiltonian describing local coupling. In an intermediate time scale, magnetic relaxation shows complex diffusional regime: the autocorrelation functions decrease in a power law with a exponent smaller than d/2 (where d is the Euclidian dimension of the system). This behavior is analogous to dynamic in low-dimensional space, but here arises from surface correlations of the porous media. The long-time behavior of the autocorrelation functions retrieves the asymptotic decrease t -d/2 . Moreover, atypical behavior is observed for the Knudsen diffusion between infinite planes. It turns out that 129 Xe NMR is a appropriate technique to characterize organization and diffusion of gas confined in Vycor. Systematic studies of temperature and pressure effect on the 129 Xe chemical shift allow to specify the Xe/solid interaction. The analysis of the relaxation measurements, thanks to the numerical development, confirms conclusions arising from the study of diffusion propagator. (author) [fr

  18. The relationships between suggestibility, influenceability, and relaxability.

    Science.gov (United States)

    Polczyk, Romuald; Frey, Olga; Szpitalak, Malwina

    2013-01-01

    This research explores the relationships between relaxability and various aspects of suggestibility and influenceability. The Jacobson Progressive Muscle Relaxation procedure was used to induce relaxation. Tests of direct suggestibility, relating to the susceptibility of overt suggestions, and indirect suggestibility, referring to indirect hidden influence, as well as self-description questionnaires on suggestibility and the tendency to comply were used. Thayer's Activation-Deactivation Adjective Check List, measuring various kinds of activation and used as a pre- and posttest, determined the efficacy of the relaxation procedure. Indirect, direct, and self-measured suggestibility proved to be positively related to the ability to relax, measured by Thayer's subscales relating to emotions. Compliance was not related to relaxability. The results are discussed in terms of the aspects of relaxation training connected with suggestibility.

  19. Hydrodynamic relaxations in dissipative particle dynamics

    Science.gov (United States)

    Hansen, J. S.; Greenfield, Michael L.; Dyre, Jeppe C.

    2018-01-01

    This paper studies the dynamics of relaxation phenomena in the standard dissipative particle dynamics (DPD) model [R. D. Groot and P. B. Warren, J. Chem. Phys. 107, 4423 (1997)]. Using fluctuating hydrodynamics as the framework of the investigation, we focus on the collective transverse and longitudinal dynamics. It is shown that classical hydrodynamic theory predicts the transverse dynamics at relatively low temperatures very well when compared to simulation data; however, the theory predictions are, on the same length scale, less accurate for higher temperatures. The agreement with hydrodynamics depends on the definition of the viscosity, and here we find that the transverse dynamics are independent of the dissipative and random shear force contributions to the stress. For high temperatures, the spectrum for the longitudinal dynamics is dominated by the Brillouin peak for large length scales and the relaxation is therefore governed by sound wave propagation and is athermal. This contrasts the results at lower temperatures and small length scale, where the thermal process is clearly present in the spectra. The DPD model, at least qualitatively, re-captures the underlying hydrodynamical mechanisms, and quantitative agreement is excellent at intermediate temperatures for the transverse dynamics.

  20. Low temperature dielectric relaxation and charged defects in ferroelectric thin films

    Directory of Open Access Journals (Sweden)

    A. Artemenko

    2013-04-01

    Full Text Available We report a dielectric relaxation in BaTiO3-based ferroelectric thin films of different composition and with several growth modes: sputtering (with and without magnetron and sol-gel. The relaxation was observed at cryogenic temperatures (T < 100 K for frequencies from 100 Hz up to 10 MHz. This relaxation activation energy is always lower than 200 meV and is very similar to the relaxation that we reported in the parent bulk perovskites. Based on our Electron Paramagnetic Resonance (EPR investigation, we ascribe this dielectric relaxation to the hopping of electrons among Ti3+-V(O charged defects. Being dependent on the growth process and on the amount of oxygen vacancies, this relaxation can be a useful probe of defects in actual integrated capacitors with no need for specific shaping.

  1. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  2. Anomalous behavior of secondary dielectric relaxation in polypropylene glycols

    Energy Technology Data Exchange (ETDEWEB)

    Grzybowska, K; Grzybowski, A; Ziolo, J; Rzoska, S J; Paluch, M [Institute of Physics, Silesian University, Uniwersytecka 4, 40-007 Katowice (Poland)

    2007-09-19

    A surprising slow down in the dielectric secondary {gamma}-relaxation with temperature increasing near the glass transition is confirmed for several polypropylene glycols. The peculiar behavior diminishes as the molecular weight grows. The minimal model (Dyre and Olsen 2003 Phys. Rev. Lett. 91 155703) is applied successfully to describe the temperature dependences of the {gamma}-relaxation times. The minimal model parameters are analyzed for different molecular weights. A molecular explanation of the {gamma}-process anomaly for polypropylene glycols is proposed on the basis of the minimal model prediction.

  3. Non-exponential dynamic relaxation in strongly nonequilibrium nonideal plasmas

    International Nuclear Information System (INIS)

    Morozov, I V; Norman, G E

    2003-01-01

    Relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics method for nonideal two-component non-degenerate plasmas. Three limiting examples of initial states of strongly nonequilibrium plasma are considered: zero electron velocities, zero ion velocities and zero velocities of both electrons and ions. The initial non-exponential stage, its duration τ nB and subsequent exponential stages of the relaxation process are studied for a wide range of the nonideality parameter and the ion mass

  4. Characterization of structural relaxation in inorganic glasses using length dilatometry

    Science.gov (United States)

    Koontz, Erick

    The processes that govern how a glass relaxes towards its thermodynamic quasi-equilibrium state are major factors in understanding glass behavior near the glass transition region, as characterized by the glass transition temperature (Tg). Intrinsic glass properties such as specific volume, enthalpy, entropy, density, etc. are used to map the behavior of the glass network below in and near the transition region. The question of whether a true thermodynamic second order phase transition takes place in the glass transition region is another pending question. Linking viscosity behavior to entropy, or viewing the glass configuration as an energy landscape are just a couple of the most prevalent methods used for attempting to understand the glass transition. The structural relaxation behavior of inorganic glasses is important for more than scientific reasons, many commercial glass processing operations including glass melting and certain forms of optical fabrication include significant time spent in the glass transition region. For this reason knowledge of structural relaxation processes can, at a minimum, provide information for annealing duration of melt-quenched glasses. The development of a predictive model for annealing time prescription has the potential to save glass manufacturers significant time and money as well as increasing volume throughput. In optical hot forming processes such as precision glass molding, molded optical components can significantly change in shape upon cooling through the glass transition. This change in shape is not scientifically predictable as of yet though manufacturers typically use empirical rules developed in house. The classification of glass behavior in the glass transition region would allow molds to be accurately designed and save money for the producers. The work discussed in this dissertation is comprised of the development of a dilatometric measurement and characterization method of structural relaxation. The measurement and

  5. Thermally induced magnetic relaxation in square artificial spin ice

    Science.gov (United States)

    Andersson, M. S.; Pappas, S. D.; Stopfel, H.; Östman, E.; Stein, A.; Nordblad, P.; Mathieu, R.; Hjörvarsson, B.; Kapaklis, V.

    2016-11-01

    The properties of natural and artificial assemblies of interacting elements, ranging from Quarks to Galaxies, are at the heart of Physics. The collective response and dynamics of such assemblies are dictated by the intrinsic dynamical properties of the building blocks, the nature of their interactions and topological constraints. Here we report on the relaxation dynamics of the magnetization of artificial assemblies of mesoscopic spins. In our model nano-magnetic system - square artificial spin ice - we are able to control the geometrical arrangement and interaction strength between the magnetically interacting building blocks by means of nano-lithography. Using time resolved magnetometry we show that the relaxation process can be described using the Kohlrausch law and that the extracted temperature dependent relaxation times of the assemblies follow the Vogel-Fulcher law. The results provide insight into the relaxation dynamics of mesoscopic nano-magnetic model systems, with adjustable energy and time scales, and demonstrates that these can serve as an ideal playground for the studies of collective dynamics and relaxations.

  6. Nuclear magnetic relaxation of methyl group in liquids

    International Nuclear Information System (INIS)

    Blicharska, B.

    1986-01-01

    The theoretical description of the relaxation process of methyl group in liquids and some results of the measurements of relaxation function and relaxation times for cryoprotective solutions are presented. Starting from the application of the operator formalism the general equation for spin operators e.g. components of the nuclear spin and magnetization is founded. Next, the spin Hamiltonian is presented as contraction of the symmetry adapted spherical tensors as well as the correlation functions and spectral densities. On the basis of extended and modified Woessner model of motion the correlation functions and spectral densities are calculated for methyl group in liquids. Using these functions the relaxation matrix elements, the spin-spin and spin-lattice relaxation times can be expressed. The prediction of the theory agrees with author's previous experiments on cryoprotective solutions. The observed dependence on temperature, frequency and isotopic dilution in methanol-water, methanol-dimethyl sulfoxide (DMSO) and DMSO-water solutions is in a satisfactory agreement with theoretical equations. 34 refs. (author)

  7. Energy equation for the analysis of magnetization relaxation to equilibrium

    Energy Technology Data Exchange (ETDEWEB)

    Bertotti, G. [IEN Galileo Ferraris, Materials Department, Strada delle Cacce, 91, I-10135 Torino (Italy)]. E-mail: bertotti@ien.it; Bonin, R. [Dipartimento di Fisica, Politecnico di Torino, I-10129 Torino (Italy); Magni, A. [IEN Galileo Ferraris, Materials Department, Strada delle Cacce, 91, I-10135 Torino (Italy); Mayergoyz, I.D. [Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland, 20742 (United States); Serpico, C. [Dipartimento di Ingegneria Elettrica, Universita di Napoli ' Federico II' , I-80125 Naples (Italy)

    2005-02-01

    Magnetization relaxation starting from a generic non-equilibrium state is analytically described. An equation for the energy decay is obtained. On this basis, an approximate expression for the magnetization motion during the ringing process is obtained in terms of Jacobi elliptic functions with time-dependent parameters.

  8. Energy equation for the analysis of magnetization relaxation to equilibrium

    International Nuclear Information System (INIS)

    Bertotti, G.; Bonin, R.; Magni, A.; Mayergoyz, I.D.; Serpico, C.

    2005-01-01

    Magnetization relaxation starting from a generic non-equilibrium state is analytically described. An equation for the energy decay is obtained. On this basis, an approximate expression for the magnetization motion during the ringing process is obtained in terms of Jacobi elliptic functions with time-dependent parameters

  9. A model for the generic alpha relaxation in viscous liquids

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2005-01-01

    Dielectric measurements on molecular liquids just above the glass transition indicate that alpha relaxation is characterized by a generic high-frequency loss varying as one over square root of frequency, whereas deviations from this come from one or more low-lying beta processes [Olsen et al., Phys...

  10. Detection of quadrupole relaxation in an optically pumped cesium vapour

    Energy Technology Data Exchange (ETDEWEB)

    Bernabeu, E; Tornos, J

    1985-10-01

    The relaxation of quadrupole orientation induced by means of optical pumping in a cesium vapour is experimentally studied, and the results are compared to the theoretical predictions. The optical detection process of this type of orientation is also discussed as a function of the polarization and spectral profile of the detection light.

  11. Stability and suppression of turbulence in relaxing molecular gas flows

    CERN Document Server

    Grigoryev, Yurii N

    2017-01-01

    This book presents an in-depth systematic investigation of a dissipative effect which manifests itself as the growth of hydrodynamic stability and suppression of turbulence in relaxing molecular gas flows. The work describes the theoretical foundations of a new way to control stability and laminar turbulent transitions in aerodynamic flows. It develops hydrodynamic models for describing thermal nonequilibrium gas flows which allow the consideration of suppression of inviscid acoustic waves in 2D shear flows. Then, nonlinear evolution of large-scale vortices and Kelvin-Helmholtz waves in relaxing shear flows are studied. Critical Reynolds numbers in supersonic Couette flows are calculated analytically and numerically within the framework of both linear and nonlinear classical energy hydrodynamic stability theories. The calculations clearly show that the relaxation process can appreciably delay the laminar-turbulent transition. The aim of the book is to show the new dissipative effect, which can be used for flo...

  12. Wall relaxation and the driving forces for cell expansive growth

    Science.gov (United States)

    Cosgrove, D. J.

    1987-01-01

    When water uptake by growing cells is prevented, the turgor pressure and the tensile stress in the cell wall are reduced by continued wall loosening. This process, termed in vivo stress relaxation, provides a new way to study the dynamics of wall loosening and to measure the wall yield threshold and the physiological wall extensibility. Stress relaxation experiments indicate that wall stress supplies the mechanical driving force for wall yielding. Cell expansion also requires water absorption. The driving force for water uptake during growth is created by wall relaxation, which lowers the water potential of the expanding cells. New techniques for measuring this driving force show that it is smaller than believed previously; in elongating stems it is only 0.3 to 0.5 bar. This means that the hydraulic resistance of the water transport pathway is small and that rate of cell expansion is controlled primarily by wall loosening and yielding.

  13. Stability investigations of relaxing molecular gas flows. Results and perspectives

    Science.gov (United States)

    Grigor'ev, Yurii N.; Ershov, Igor V.

    2017-10-01

    This article presents results of systematic investigations of a dissipative effect which manifests itself as the growth of hydrodynamic stability and suppression of turbulence in relaxing molecular gas flows. The effect can be a new way for control stability and laminar turbulent transition in aerodynamic flows. The consideration of suppression of inviscid acoustic waves in 2D shear flows is presented. Nonlinear evolution of large-scale vortices and Kelvin — Helmholtz waves in relaxing shear flows are studied. Critical Reynolds numbers in supersonic Couette flows are calculated analytically and numerically within the framework of both classical linear and nonlinear energy hydrodynamic stability theories. The calculations clearly show that the relaxation process can appreciably delay the laminar-turbulent transition. The aim of this article is to show the new dissipative effect, which can be used for flow control and laminarization.

  14. Arginase strongly impairs neuronal nitric oxide-mediated airway smooth muscle relaxation in allergic asthma

    NARCIS (Netherlands)

    Maarsingh, H; Leusink, J; Bos, I Sophie T; Zaagsma, J; Meurs, H

    2006-01-01

    Background: Using guinea pig tracheal preparations, we have recently shown that endogenous arginase activity attenuates inhibitory nonadrenergic noncholinergic (iNANC) nerve-mediated airway smooth muscle relaxation by reducing nitric oxide (NO) production - due to competition with neuronal

  15. Escape time, relaxation, and sticky states of a softened Henon-Heiles model: Low-frequency vibrational mode effects and glass relaxation

    Science.gov (United States)

    Toledo-Marín, J. Quetzalcóatl; Naumis, Gerardo G.

    2018-04-01

    Here we study the relaxation of a chain consisting of three masses joined by nonlinear springs and periodic conditions when the stiffness is weakened. This system, when expressed in their normal coordinates, yields a softened Henon-Heiles system. By reducing the stiffness of one low-frequency vibrational mode, a faster relaxation is enabled. This is due to a reduction of the energy barrier heights along the softened normal mode as well as for a widening of the opening channels of the energy landscape in configurational space. The relaxation is for the most part exponential, and can be explained by a simple flux equation. Yet, for some initial conditions the relaxation follows as a power law, and in many cases there is a regime change from exponential to power-law decay. We pinpoint the initial conditions for the power-law decay, finding two regions of sticky states. For such states, quasiperiodic orbits are found since almost for all components of the initial momentum orientation, the system is trapped inside two pockets of configurational space. The softened Henon-Heiles model presented here is intended as the simplest model in order to understand the interplay of rigidity, nonlinear interactions and relaxation for nonequilibrium systems such as glass-forming melts or soft matter. Our softened system can be applied to model β relaxation in glasses and suggest that local reorientational jumps can have an exponential and a nonexponential contribution for relaxation, the latter due to asymmetric molecules sticking in cages for certain orientations.

  16. Law n. 13.015/2014: Amendment of Labor Magazine Feature and Possible offenses to Constitutional Principles of Due Process Legal Access to Jurisdiction and Effectiveness

    Directory of Open Access Journals (Sweden)

    Sérgio Henriques Zandona Freitas

    2015-12-01

    Full Text Available This scientific article aims to study the reforms undertaken by the Law 13.015/2014 under the proposed amendments to the labor resources of magazines, and a growing demand in the edition of overviews by the Regionals Labors Court. At first, the theoretical basis, we analyze the prospects of the constitutional process model within the framework leveraged as a democratic state. After, it enters to the principle concept of due process of law, the access Jurisdiction and Effectiveness, doing, in a third moment, a brief survey and survey as the main proposals of changes made by Law n. 13.015/2014, demonstrating the likelihood that some provisions of this standard or not contradict principles and constitutional guarantees. Trough the deductive method and the bibliographic research this article has been written from a large conception to a small one. And as technical proceeding were used the theme analysis as a way of looking for a solution for the problem.

  17. Online interferometric study of viscoelastic rupture and necking deformation of as-spun (iPP) fibres due to creep process.

    Science.gov (United States)

    Sokkar, Taha; El-Farahaty, Kermal; Azzam, Amira

    2015-01-01

    Creep deformation under constant load leads to rupture when the polymer chains can no longer separate and accommodate the load. This fracture phenomenon is investigated interferometrically. The creep behaviour of as-spun isotactic Polypropylene (iPP) fibres is studied at different stresses, different initial lengths and different radii. The creep rate, which defines the velocity of the creep deformation and the dimensional stability of the material, is studied. The failure time and stress of iPP due to creep process is determined. The necking deformation was in situ detected during creep process. The mean refractive indices (n(P) andn⊥) profiles of iPP fibres were determined at different positions along the fibre axis before and after necking. The relation between the creep behaviour and different optical and structural parameters is investigated. Microinterferograms are given for illustration. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  18. Rotation and scale change invariant point pattern relaxation matching by the Hopfield neural network

    Science.gov (United States)

    Sang, Nong; Zhang, Tianxu

    1997-12-01

    Relaxation matching is one of the most relevant methods for image matching. The original relaxation matching technique using point patterns is sensitive to rotations and scale changes. We improve the original point pattern relaxation matching technique to be invariant to rotations and scale changes. A method that makes the Hopfield neural network perform this matching process is discussed. An advantage of this is that the relaxation matching process can be performed in real time with the neural network's massively parallel capability to process information. Experimental results with large simulated images demonstrate the effectiveness and feasibility of the method to perform point patten relaxation matching invariant to rotations and scale changes and the method to perform this matching by the Hopfield neural network. In addition, we show that the method presented can be tolerant to small random error.

  19. Stress relaxation experiments on a lamellar polystyrene-polyisoprene diblock copolymer melt

    DEFF Research Database (Denmark)

    Holmqvist, P.; Castelletto, V.; Hamley, I.W.

    2001-01-01

    The non-linear rheology of the lamellar phase of a polystyrene-polyisoprene diblock copolymer is studied by oscillatory shear experiments. The relaxation of the shear modulus, G(t, gamma) is studied as a function of strain amplitude, gamma, up to large amplitude strains, gamma = 100%. The decay...... of G(t, gamma) is analysed using the model-independent CONTIN inverse Laplace transform algorithm to obtain a series of relaxation times, which reveals multiple relaxation processes. The timescale for the fastest relaxation processes is compared to those previously observed for diblock copolymer melts...... via dynamic light scattering experiments. The slowest relaxation process may be related to the shear-induced orientation of the lamellae. It is shown that time-strain separability G(t, gamma)= G(t)h(gamma) can be applied, and the damping function h(gamma) is consistent with a strongly strain...

  20. Post-seismic relaxation from geodetic and seismic data

    Directory of Open Access Journals (Sweden)

    Mikhail V. Rodkin

    2017-01-01

    Full Text Available We have examined the aftershock sequence and the post-seismic deformation process of the Parkfield earthquake (2004, M = 6, California, USA source area using GPS data. This event was chosen because of the possibility of joint analysis of data from the rather dense local GPS network (from SOPAC Internet archive and of the availability of the rather detailed aftershock sequence data (http://www.ncedc.org/ncedc/catalog-search.html. The relaxation process of post-seismic deformation prolongs about the same 400 days as the seismic aftershock process does. Thus, the aftershock process and the relaxation process in deformation could be the different sides of the same process. It should be noted that the ratio of the released seismic energy and of the GPS obtained deformation is quite different for the main shock and for the aftershock stage. The ratio of the released seismic energy to the deformation value decreases essentially for the post-shock process. The similar change in the seismic energy/deformation value ratio is valid in a few other strong earthquakes. Thus, this decrease seems typical of aftershock sequences testifying for decrease of ratio of elastic to inelastic deformation in the process of post-shock relaxation when the source area appears to be mostly fractured after the main shock occurs, but the healing process had no yet sufficient time to develop.

  1. Cherenkov and anomalous Doppler effects in the relaxation of an electron beam

    International Nuclear Information System (INIS)

    Muschietti, L.; Appert, K.; Vaclavik, J.

    1981-01-01

    The interplay between the Cherenkov and anomalous Doppler interactions in the relaxation of a warm electron beam is investigated by numerical means. The most important feature in the interplay is found to be a nonelastic isotropization. A simple semianalytical model which allows one to estimate various quantities relevant to the relaxation process is also presented

  2. Ultrasonic relaxations in borate glasses

    International Nuclear Information System (INIS)

    D'Angelo, G.; Tripodo, G.; Carini, G.; Cosio, E.; Bartolotta, A.; Di Marco, G.

    2004-01-01

    The attenuation and velocity of ultrasonic waves of frequencies in the range from 10 to 70 MHz have been measured in M 2 O-B 2 O 3 borate glasses (M: Li or Ag) as a function of temperature between 15 and 350 K. The velocity of sound waves decreases with increasing temperature in all the glasses, the decrease as the temperature is increased is larger in glasses containing silver than in those with lithium. A broad relaxation peak characterises the attenuation behaviour of the lithium and silver borate glasses at temperatures below 100 K and is paralleled by a corresponding dispersive behaviour of the sound velocity. Above 100 K, the ultrasonic velocity shows a nearly linear behaviour regulated by the vibrational anharmonicity, which decreases with increasing content of modifier oxide and is smaller in lithium than in silver borates. These results suggest that the relaxation of structural defects and the anharmonicity of borate glasses are strongly affected by two parameters: the number of bridging bonds per network forming ion and the polarising power of network modifier ions which occupy sites in the existing interstices

  3. Statistical mechanics of violent relaxation

    International Nuclear Information System (INIS)

    Shu, F.H.

    1978-01-01

    We reexamine the foundations of Lynden-Bell's statistical mechanical discussion of violent relaxation in collisionless stellar systems. We argue that Lynden-Bell's formulation in terms of a continuum description introduces unnecessary complications, and we consider a more conventional formulation in terms of particles. We then find the exclusion principle discovered by Lynden-Bell to be quantitatively important only at phase densities where two-body encounters are no longer negligible. Since the edynamical basis for the exclusion principle vanishes in such cases anyway, Lynden-Bell statistics always reduces in practice to Maxwell-Boltzmann statistics when applied to stellar systems. Lynden-Bell also found the equilibrium distribution function generally to be a sum of Maxwellians with velocity dispersions dependent on the phase density at star formation. We show that this difficulty vanishes in the particulate description for an encounterless stellar system as long as stars of different masses are initially well mixed in phase space. Our methods also demonstrate the equivalence between Gibbs's formalism which uses the microcanonical ensemble and Boltzmann's formalism which uses a coarse-grained continuum description. In addition, we clarify the concept of irreversible behavior on a macroscopic scale for an encounterless stellar system. Finally, we comment on the use of unusual macroscopic constraints to simulate the effects of incomplete relaxation

  4. Grid Cell Relaxation Effects on the High Frequency Vibration Characteristics

    International Nuclear Information System (INIS)

    Ryu, Joo-Young; Eom, Kyong-Bo; Jeon, Sang-Youn; Kim, Jae-Ik

    2015-01-01

    The plate structure of the grid of fuel assembly is always exposed to serious vortex induced vibration. Also, High Frequency flow induced Vibration (HFV) is primarily generated by vortex-shedding effect. When it comes to grid design as a fuel assembly component, HFV should be considered in advance since it is one of the critical factors. Excessive HFV has a possibility of making degradation of the fuel reliability that is directly related to the fuel robustness and operating performance. KEPCO NF (KNF) has performed HFV tests with various grid designs. While studying the HFV characteristics through the HFV tests, it has been observed that HFV amplitudes show different levels according to grid cell relaxation. It means that the testing could give different interpretations due to the condition of grid cell. Since the amount of relaxation is different under operating conditions and environments in a reactor, test specimens should be modified as much as possible to the real state of the fuel. Therefore, in order to consider the grid cell relaxation effects on the HFV tests, it is important to use cell sized or non-cell sized grids. The main focus of this study is to find out how the HFV characteristics such as amplitude and frequency are affected by grid cell relaxation. Three cases of the grid cell sized specimen which is nickel alloy were prepared and tested. Through the comparison of the test results, it could be concluded that HFV amplitudes show decreasing trend according to the grid cell relaxation in the case of nickel alloy grid. It is also possible to expect the tendency of grid cell relaxation of a zirconium alloy grid based on test results

  5. Spin relaxation in quantum dots: Role of the phonon modulated spin-orbit interaction

    Science.gov (United States)

    Alcalde, A. M.; Romano, C. L.; Sanz, L.; Marques, G. E.

    2010-01-01

    We calculate the spin relaxation rates in a parabolic InSb quantum dots due to the spin interaction with acoustical phonons. We considered the deformation potential mechanism as the dominant electron-phonon coupling in the Pavlov-Firsov spin-phonon Hamiltonian. We analyze the behavior of the spin relaxation rates as a function of an external magnetic field and mean quantum dot radius. Effects of the spin admixture due to Dresselhaus contribution to spin-orbit interaction are also discussed.

  6. Brand-name drug, generic drug, orphan drug. Pharmacological therapy with biosimilar drugs – provision of due diligence in the treatment process

    Science.gov (United States)

    Zajdel, Justyna

    2013-01-01

    Due diligence in the process of provision of healthcare services refers, among other elements, to the application of pharmacological therapy at a time which offers the greatest chance for a successful outcome of treatment, i.e. for achieving the optimum expected effect understood as an improvement in the patient's health, reduction of health risks or elimination of the disease. However, due diligence may also refer to actions aimed at ensuring that neither the patient nor the healthcare payer is required to incur unreasonable costs in the process of treatment. The validity of that statement stems not only from normative acts but also from ethical standards laid down in the Medical Code of Ethics (Article 57 section 2). It often happens that the provision of optimal treatment calls for deviations from the formal provisions included in Summary Product Characteristics (SPCs), and the application of drugs that are bioequivalent to reference drugs, which translates into a significant reduction of costs. The present study addresses the problem of acceptability of a specific form of drug substitution consisting in the replacement of a reference drug with a generic drug. Also explored are legal aspects associated with the possibility of therapy based on “off-label use”. The study reviews normative acts existing in the Polish and EU legislation. It also provides a clear definition of orphan drug, which has made it possible to make a distinction and investigate mutual relations between the concepts of brand-name (reference) drug, orphan drug and generic drug. PMID:24592133

  7. Brand-name drug, generic drug, orphan drug. Pharmacological therapy with biosimilar drugs - provision of due diligence in the treatment process.

    Science.gov (United States)

    Zajdel, Justyna; Zajdel, Radosław

    2013-01-01

    Due diligence in the process of provision of healthcare services refers, among other elements, to the application of pharmacological therapy at a time which offers the greatest chance for a successful outcome of treatment, i.e. for achieving the optimum expected effect understood as an improvement in the patient's health, reduction of health risks or elimination of the disease. However, due diligence may also refer to actions aimed at ensuring that neither the patient nor the healthcare payer is required to incur unreasonable costs in the process of treatment. The validity of that statement stems not only from normative acts but also from ethical standards laid down in the Medical Code of Ethics (Article 57 section 2). It often happens that the provision of optimal treatment calls for deviations from the formal provisions included in Summary Product Characteristics (SPCs), and the application of drugs that are bioequivalent to reference drugs, which translates into a significant reduction of costs. The present study addresses the problem of acceptability of a specific form of drug substitution consisting in the replacement of a reference drug with a generic drug. Also explored are legal aspects associated with the possibility of therapy based on "off-label use". The study reviews normative acts existing in the Polish and EU legislation. It also provides a clear definition of orphan drug, which has made it possible to make a distinction and investigate mutual relations between the concepts of brand-name (reference) drug, orphan drug and generic drug.

  8. Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials.

    Science.gov (United States)

    Hansen, Barbara C; Gografe, Sylvia; Pritt, Stacy; Jen, Kai-Lin Catherine; McWhirter, Camille A; Barman, Susan M; Comuzzie, Anthony; Greene, Molly; McNulty, Justin A; Michele, Daniel Eugene; Moaddab, Naz; Nelson, Randall J; Norris, Karen; Uray, Karen D; Banks, Ron; Westlund, Karin N; Yates, Bill J; Silverman, Jerald; Hansen, Kenneth D; Redman, Barbara

    2017-10-01

    Every institution that is involved in research with animals is expected to have in place policies and procedures for the management of allegations of noncompliance with the Animal Welfare Act and the U.S. Public Health Service Policy on the Humane Care and Use of Laboratory Animals. We present here a model set of recommendations for institutional animal care and use committees and institutional officials to ensure appropriate consideration of allegations of noncompliance with federal Animal Welfare Act regulations that carry a significant risk or specific threat to animal welfare. This guidance has 3 overarching aims: 1 ) protecting the welfare of research animals; 2 ) according fair treatment and due process to an individual accused of noncompliance; and 3 ) ensuring compliance with federal regulations. Through this guidance, the present work seeks to advance the cause of scientific integrity, animal welfare, and the public trust while recognizing and supporting the critical importance of animal research for the betterment of the health of both humans and animals.-Hansen, B. C., Gografe, S., Pritt, S., Jen, K.-L. C., McWhirter, C. A., Barman, S. M., Comuzzie, A., Greene, M., McNulty, J. A., Michele, D. E., Moaddab, N., Nelson, R. J., Norris, K., Uray, K. D., Banks, R., Westlund, K. N., Yates, B. J., Silverman, J., Hansen, K. D., Redman, B. Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials. © FASEB.

  9. Comparison between the results of stress relaxation - and creep tests in a stainless steel 316 at 8000C

    International Nuclear Information System (INIS)

    Miranda, P.E.V. de.

    1978-07-01

    A sequence of stress relaxation tests from the same initial stress showed an estabilization of the relaxed fraction of stress of a 316 stainless steel at 800 0 C. This represents the exhaustion of the deformation process of the material at this temperature. Results from the relaxation tests were obtained by utilizing a recently proposed model. The slope in from the log epsilon sup(.) x logσ/E curve obtained by relaxation (n = 6,80) closely matched that determined by creep tests (n = 6,50). This presents a possibility of determined by stress relaxation of the parameters usually calculated by creep. (Author) [pt

  10. Meghan Rene, et al., v. Dr. Suellen Reed, et al. "Due Process." Lesson Plans for Secondary School Teachers on the Constitutional Requirement of "Due Process of Law." Courts in the Classroom: Curriculum Concepts and Other Information on Indiana's Courts for the K-12 Educator.

    Science.gov (United States)

    Osborn, Elizabeth

    In the Rene v. Reed case, Meghan Rene and other disabled students argued that their due process rights were violated in regard to the Indiana Statewide Testing for Educational Progress (ISTEP) graduation examination. This set of four lesson plans uses the case of Rene v. Reed, which was first argued before the Indiana Supreme Court, to study the…

  11. Paramagnetic relaxation effects in perturbed angular correlations for arbitrary electronic relaxation time

    International Nuclear Information System (INIS)

    Chopin, C.; Spanjaard, D.; Hartmann-Boutron, F.

    1975-01-01

    Previous perturbation treatments of paramagnetic relaxation effects in γγ PAC were limited to the case of very short electronic relaxation times. This limitation is circumvented by invoking a new perturbation theory recently elaborated by Hirst and others for handling relaxation effects in Moessbauer spectra. Under the assumption of spherical electronic relaxation the perturbation factors are computed as functions of certain relaxation parameters which are directly related to the microscopic relaxation Hamiltonian. The results are compared to those of the stochastic theory of Scherer and Blume [fr

  12. Suppression of Raman electron spin relaxation of radicals in crystals. Comparison of Cu2+ and free radical relaxation in triglycine sulfate and Tutton salt single crystals.

    Science.gov (United States)

    Hoffmann, S K; Goslar, J; Lijewski, S

    2011-08-31

    Electron spin-lattice relaxation was measured by the electron spin echo method in a broad temperature range above 4.2 K for Cu(2+) ions and free radicals produced by ionizing radiation in triglycine sulfate (TGS) and Tutton salt (NH4)(2)Zn(SO4)2 ⋅ 6H2O crystals. Localization of the paramagnetic centres in the crystal unit cells was determined from continuous wave electron paramagnetic resonance spectra. Various spin relaxation processes and mechanisms are outlined. Cu(2+) ions relax fast via two-phonon Raman processes in both crystals involving the whole phonon spectrum of the host lattice. This relaxation is slightly slower for TGS where Cu(2+) ions are in the interstitial position. The ordinary Raman processes do not contribute to the radical relaxation which relaxes via the local phonon mode. The local mode lies within the acoustic phonon band for radicals in TGS but within the optical phonon range in (NH4)(2)Zn(SO4)2 ⋅ 6H2O. In the latter the cross-relaxation was considered. A lack of phonons around the radical molecules suggested a local crystal amorphisation produced by x- or γ-rays.

  13. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin......-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...... the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent....

  14. Variation Process of Radiation Belt Electron Fluxes due to Interaction With Chorus and EMIC Rising-tone Emissions Localized in Longitude

    Science.gov (United States)

    Kubota, Y.; Omura, Y.

    2017-12-01

    Using results of test particle simulations of a large number of electrons interacting with a pair of chorus emissions, we create Green's functions to model the electron distribution function after all of the possible interactions with the waves [Omura et al., 2015]. Assuming that the waves are generated in a localized range of longitudes in the dawn side, we repeat taking the convolution integral of the Green's function with the distribution function of the electrons injected into the generation region of the localized waves. From numerical and theoretical analyses, we find that electron acceleration process only takes place efficiently below 4 MeV. Because extremely relativistic electrons go through the wave generation region rapidly due to grad-B0 and curvature drift, they don't have enough interaction time to be accelerated. In setting up the electrons after all interaction with chorus emissions as initial electron distribution function, we also compute the loss process of radiation belt electron fluxes due to interaction with EMIC rising-tone emissions generated in a localized range of longitudes in the dusk side [Kubota and Omura,2017]. References: (1) Omura, Y., Y. Miyashita, M. Yoshikawa, D. Summers, M. Hikishima, Y. Ebihara, and Y. Kubota (2015), Formation process of relativistic electron flux through interaction with chorus emissions in the Earth's inner magnetosphere, J. Geophys. Res. Space Physics, 120, 9545-9562, doi:10.1002/2015JA021563. (2) Kubota, Y., and Y. Omura (2017), Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause, J. Geophys. Res. Space Physics, 122, 293-309, doi:10.1002/2016JA023267.

  15. Due diligence

    OpenAIRE

    Rohanová, Tereza

    2015-01-01

    One of the main strategic goals of an owner is the growth of their company. To seek company growth in todays ever changing world, company owners and their management frequently turn to the discipline of mergers and acquisitions (hereinafter M&A). This M&A focus is evidenced by the sustained long term growth of the M&A markets, which for example in the Czech Republic alone amounted to a 38% increase between the years 2015 and 2016. The transaction decision making process takes place with an in...

  16. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  17. Resonant tunneling measurements of size-induced strain relaxation

    Science.gov (United States)

    Akyuz, Can Deniz

    Lattice mismatch strain available in such semiconductor heterostructures as Si/SiGe or GaAs/AlGaAs can be employed to alter the electronic and optoelectronic properties of semiconductor structures and devices. When deep submicron structures are fabricated from strained material, strained layers relax by sidewall expansion giving rise to size- and geometry-dependent strain gradients throughout the structure. This thesis describes a novel experimental technique to probe the size-induced strain relaxation by studying the tunneling current characteristics of strained p-type Si/SiGe resonant tunneling diodes. Our current-voltage measurements on submicron strained p-Si/SiGe double- and triple-barrier resonant tunneling structures as a function of device diameter, D, provide experimental access to both the average strain relaxation (which leads to relative shifts in the tunneling current peak positions) and strain gradients (which give rise to a fine structure in the current peaks due to inhomogeneous strain-induced lateral quantization). We find that strain relaxation is significant, with a large fraction of the strain energy relaxed on average in D ≤ 0.25 m m devices. Further, the in-plane potentials that arise from inhomogeneous strain gradients are large. In the D ˜ 0.2 m m devices, the corresponding lateral potentials are approximately parabolic exceeding ˜ 25 meV near the perimeter. These potentials create discrete hole states in double-barrier structures (single well), and coupled hole states in triple-barrier structures (two wells). Our results are in excellent agreement with finite-element strain calculations in which the strained layers are permitted to relax to a state of minimum energy by sidewall expansion. Size-induced strain relaxation will undoubtedly become a serious technological issue once strained devices are scaled down to the deep submicron regime. Interestingly, our calculations predict and our measurements are consistent with the appearance of

  18. Dielectric Relaxation of Water: Theory and Experiment

    International Nuclear Information System (INIS)

    Adhikari, Narayan Prasad; Paudyal, Harihar; Johri, Manoj

    2010-06-01

    We have studied the hydrogen bond dynamics and methods for evaluation of probability and relaxation time for hydrogen bond network. Further, dielectric relaxation time has been calculated by using a diagonalization procedure by obtaining eigen values (inverse of relaxation time) of a master equation framed on the basis of Fokker-Planck equations. Microwave cavity spectrometer has been described to make measurements of relaxation time. Slater's perturbation equations are given for the analysis of the data. A comparison of theoretical and experimental data shows that there is a need for improvements in the theoretical model and experimental techniques to provide exact information about structural properties of water. (author)

  19. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  20. Relaxing Chosen-Ciphertext Security

    DEFF Research Database (Denmark)

    Canetti, Ran; Krawczyk, Hugo; Nielsen, Jesper Buus

    2003-01-01

    Security against adaptive chosen ciphertext attacks (or, CCA security) has been accepted as the standard requirement from encryption schemes that need to withstand active attacks. In particular, it is regarded as the appropriate security notion for encryption schemes used as components within...... general protocols and applications. Indeed, CCA security was shown to suffice in a large variety of contexts. However, CCA security often appears to be somewhat too strong: there exist encryption schemes (some of which come up naturally in practice) that are not CCA secure, but seem sufficiently secure...... “for most practical purposes.” We propose a relaxed variant of CCA security, called Replayable CCA (RCCA) security. RCCA security accepts as secure the non-CCA (yet arguably secure) schemes mentioned above; furthermore, it suffices for most existing applications of CCA security. We provide three...

  1. Diffusion in confinement as a microscopic relaxation mechanism in glass-forming liquids

    International Nuclear Information System (INIS)

    Mamontov, Eugene

    2012-01-01

    Using quasielastic neutron scattering, we compare dynamics in single-element liquids, glass-forming selenium and non glass-forming gallium. There is a single jump-diffusion process in gallium, whereas in selenium there is also a faster, spatially localized process. The fast and slow processes describe β- and α-relaxation, respectively. We then analyze an archetypical glass-former, glycerol, to show that the two-component fit, with β- and α-relaxations explicitly separated, yields the correct value for the translational diffusion coefficient and provides information on the spatial localization of the β-relaxation that is not experimentally accessible otherwise.

  2. A model of anelastic relaxation associated with polygonization boundary

    International Nuclear Information System (INIS)

    Yan, S.C.

    1990-01-01

    A model of anelastic relaxation associated with polygonization boundary is proposed in order to explain internal friction peaks and other experimental phenomena observed recently. The model, which is referred to as vacancy-thermal jog model, shows that under conditions of high temperature and low applied stress with lower frequencies of vibration, thermal jog pairs are generated on dislocation segments of the boundaries. These jogs are in saturation with vacancies in the vicinity of them, and the vacancy current due to the concentration gradient of vacancy drifts among the boundaries. As a result, a diffusional creep is produced and a part of energy is dissipated. For vacancy drift, it is required that the thermal jogs emit (absorb) vacancies, which brings climbing bow of segments into operation, and another part of energy is dissipated so that there are two parts of energy dissipated in the strain process connected with polygonization boundary. Based on this point of view, the mathematical expressions of internal friction and modulus defect associated with polygonization boundary were subsequently derived and found to be in satisfactory agreement with experiments. (author). 13 refs, 6 figs

  3. Relaxation rates of low-field gas-phase ^129Xe storage cells

    Science.gov (United States)

    Limes, Mark; Saam, Brian

    2010-10-01

    A study of longitudinal nuclear relaxation rates T1 of ^129Xe and Xe-N2 mixtures in a magnetic field of 3.8 mT is presented. In this regime, intrinsic spin relaxation is dominated by the intramolecular spin-rotation interaction due to persistent xenon dimers, a mechanism that can be quelled by introducing large amounts of N2 into the storage cell. Extrinsic spin relaxation is dominated by the wall-relaxation rate, which is the primary quantity of interest for the various low-field storage cells and coatings that we have tested. Previous group work has shown that extremely long gas-phase relaxation times T1 can be obtained, but only at large magnetic fields and low xenon densities. The current work is motivated by the practical benefits of retaining hyperpolarized ^129Xe for extended periods of time in a small magnetic field.

  4. Spin-lattice relaxation of individual solid-state spins

    Science.gov (United States)

    Norambuena, A.; Muñoz, E.; Dinani, H. T.; Jarmola, A.; Maletinsky, P.; Budker, D.; Maze, J. R.

    2018-03-01

    Understanding the effect of vibrations on the relaxation process of individual spins is crucial for implementing nanosystems for quantum information and quantum metrology applications. In this work, we present a theoretical microscopic model to describe the spin-lattice relaxation of individual electronic spins associated to negatively charged nitrogen-vacancy centers in diamond, although our results can be extended to other spin-boson systems. Starting from a general spin-lattice interaction Hamiltonian, we provide a detailed description and solution of the quantum master equation of an electronic spin-one system coupled to a phononic bath in thermal equilibrium. Special attention is given to the dynamics of one-phonon processes below 1 K where our results agree with recent experimental findings and analytically describe the temperature and magnetic-field scaling. At higher temperatures, linear and second-order terms in the interaction Hamiltonian are considered and the temperature scaling is discussed for acoustic and quasilocalized phonons when appropriate. Our results, in addition to confirming a T5 temperature dependence of the longitudinal relaxation rate at higher temperatures, in agreement with experimental observations, provide a theoretical background for modeling the spin-lattice relaxation at a wide range of temperatures where different temperature scalings might be expected.

  5. The relaxational behaviour of poly-(vinylidene fluoride) before and after gamma-irradiation

    International Nuclear Information System (INIS)

    Callens, A.

    The main purpose of this work was to investigate how molecular chain reorganization may affect the physical property of polymers. This may be done by the analysis of the as received and post-irradiation relaxation spectra of the semi-crystalline linear chain polymer polyvinylidene fluoride (PVDF), which has been gamma-irradiated up to doses of 1 grad. The effects of the irradiation on the material are primarly main chain cross-linking production of unsaturated bonds and crystallite degradation. To reach a complete interpretation of the relaxation spectra, it is necessary to incorporate a third phase into the analysis besides the amorphous viscoelastic region (AVR) and the crystalline viscoelastic region (CVR), the intermediate phase. The amorphous phase (AVR) is at the origin of the relaxation effects occurring in the temperature region below room temperature. The saturation like behaviour of the cross-linking in the amorphous phase is at the origin of the intensity decrease, temperature shift and peak broadening of the beta relaxation. There is a large amount of evidence that in the neighbourhood of the beta relaxation, relaxation effects are created through irradiation, as mainly revealed by TSD-spectra (thermalloy stimulated depolarisation). The intensity of the gamma relaxation, gradually increases with dose, which has been attributed to the production of disordered chain from the debris of radiation enhanced crystallite destruction. The relaxation effect, occuring at the temperatures between AVR and CVR, is assigned to the long amorphous chain segments attached partly to the crystallites, mainly from the consideration of the similarity of the dose enhanced decrease in intensity of both beta and βsub(μ)-effects. The increase with dose of the intensity of the α1 relaxation, which has been classified within CVR, confirms the grainboundary hypothesis. The second component of CVR (α2 relaxation) is due to relaxation effects of molecular chains belonging to the

  6. Resonance and nuclear relaxation in GdCo2

    International Nuclear Information System (INIS)

    Barata, A.C.

    1988-04-01

    A study of the 59 Co nuclear magnetic resonance and relaxation was made on the intermetallic compound GdCo 2 from 4,2 k to 330 k using the spin echo technique. An oscillatory behaviour of the primary echo was observed in the whole range of temperatures studied. This is due to the electronic quadrupole interaction of the 59 Co nuclei. (A.C.A.S.) [pt

  7. Integrated batch production and maintenance scheduling for multiple items processed on a deteriorating machine to minimize total production and maintenance costs with due date constraint

    Directory of Open Access Journals (Sweden)

    Zahedi Zahedi

    2016-04-01

    Full Text Available This paper discusses an integrated model of batch production and maintenance scheduling on a deteriorating machine producing multiple items to be delivered at a common due date. The model describes the trade-off between total inventory cost and maintenance cost as the increase of production run length. The production run length is a time bucket between two consecutive preventive maintenance activities. The objective function of the model is to minimize total cost consisting of in process and completed part inventory costs, setup cost, preventive and corrective maintenance costs and rework cost. The problem is to determine the optimal production run length and to schedule the batches obtained from determining the production run length in order to minimize total cost.

  8. Broadband generation by multiple four-wave mixing process due to ASE Q-switching in high-power double-clad ytterbium-doped fiber amplifier

    Science.gov (United States)

    Chowdhury, Sourav D.; Shekhar, Nishant; Saha, Maitreyee; Sen, Ranjan; Pal, Mrinmay

    2014-11-01

    Broadband output from 1060nm to 1700nm and cascaded four-wave mixing generated red light pulsing is observed in a fiber amplifier set up consisting of a 5.5m double clad, double D shaped Ytterbium doped fiber, a single clad passive fiber for excess pump absorption and a splitter, both with and without a CW seed. Self-pulsing occurs from ASE due to passive Q-switching by saturable absorption effect of the active fiber and also depends on splice loss. The pulses generate broadband output by multiple four-wave mixing process with maximum broadening efficiency near 1300nm which is the zero dispersion wavelength for silica fiber. Pulses traveling both in forward and backward direction have enough peak power and energy to damage splice points and fiber components. When seeded the self-pulsing and broadband generation is often suppressed but again generate at increased pump powers.

  9. β-distribution for Reynolds stress and turbulent heat flux in relaxation turbulent boundary layer of compression ramp

    Science.gov (United States)

    Hu, YanChao; Bi, WeiTao; Li, ShiYao; She, ZhenSu

    2017-12-01

    A challenge in the study of turbulent boundary layers (TBLs) is to understand the non-equilibrium relaxation process after sep-aration and reattachment due to shock-wave/boundary-layer interaction. The classical boundary layer theory cannot deal with the strong adverse pressure gradient, and hence, the computational modeling of this process remains inaccurate. Here, we report the direct numerical simulation results of the relaxation TBL behind a compression ramp, which reveal the presence of intense large-scale eddies, with significantly enhanced Reynolds stress and turbulent heat flux. A crucial finding is that the wall-normal profiles of the excess Reynolds stress and turbulent heat flux obey a β-distribution, which is a product of two power laws with respect to the wall-normal distances from the wall and from the boundary layer edge. In addition, the streamwise decays of the excess Reynolds stress and turbulent heat flux also exhibit power laws with respect to the streamwise distance from the corner of the compression ramp. These results suggest that the relaxation TBL obeys the dilation symmetry, which is a specific form of self-organization in this complex non-equilibrium flow. The β-distribution yields important hints for the development of a turbulence model.

  10. The Effects of Progressive Relaxation and Music on Attention, Relaxation, and Stress Responses: An Investigation of the Cognitive-Behavioral Model of Relaxation

    National Research Council Canada - National Science Library

    Scheufele, Peter

    1999-01-01

    ...) suggested that stress management techniques have specific effects A compromise position suggests that the specific effects of relaxation techniques are superimposed upon a general relaxation response...

  11. Assessment of structural integrity of Monju steel liner against sodium leakage and combustion. Modeling of thinning process of liner due to corrosion in structural analysis

    International Nuclear Information System (INIS)

    Tsukimori, K.; Kato, T.; Furuhashi, I.; Iwata, K.; Akatsu, M.

    2001-01-01

    The lining structure of LMFBR (Liquid Metal cooled Fast Breeder Reactor) has an important role to prohibit leaking sodium from touching a concrete floor in a sodium leakage incident. JNC (Japan Nuclear Cycle Development Institute) experienced a sodium leakage incident in 1995 in the secondary heat transport system room of the prototype LMFBR MONJU. In this incident, a part of the liner was covered with a certain amount of high temperature leaked sodium and its compounds. Visible but small distortion and thinning of the liner were detected, which were due to heating by sodium fire and chemical corrosion, respectively. To simulate the MONJU incident, JNC conducted a series of sodium leakage tests, in one of which severer corrosion (molten salt type corrosion) than that in the MONJU incident was observed. In order to secure the conservativeness in the integrity assessment of the liner, consideration of a severest corrosion process was demanded. This means that the loss of parts of the structure with time should be considered in the structural analyses. In this study a modeling of thinning process of the liner was developed in order to realize reasonable analysis from the point of view of actual phenomena. The concept of the method is to release the stress of the lost region by using artificial creep and reducing Young's modulus. The necessity of this kind of model and the validity was verified through an application analysis of the liner in the secondary heat transport system room of MONJU. (authors)

  12. Lifshitz quasinormal modes and relaxation from holography

    NARCIS (Netherlands)

    Sybesma, Watse|info:eu-repo/dai/nl/369283074; Vandoren, Stefan|info:eu-repo/dai/nl/304830739

    2015-01-01

    We obtain relaxation times for field theories with Lifshitz scaling and with holographic duals Einstein-Maxwell-Dilaton gravity theories. This is done by computing quasinormal modes of a bulk scalar field in the presence of Lifshitz black branes. We determine the relation between relaxation time and

  13. Superparamagnetic relaxation of weakly interacting particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Tronc, Elisabeth

    1994-01-01

    The influence of particle interactions on the superparamagnetic relaxation time has been studied by Mossbauer spectroscopy in samples of maghemite (gamma-Fe2O3) particles with different particle sizes and particle separations. It is found that the relaxation time decreases with decreasing particl...

  14. Models of Flux Tubes from Constrained Relaxation

    Indian Academy of Sciences (India)

    tribpo

    J. Astrophys. Astr. (2000) 21, 299 302. Models of Flux Tubes from Constrained Relaxation. Α. Mangalam* & V. Krishan†, Indian Institute of Astrophysics, Koramangala,. Bangalore 560 034, India. *e mail: mangalam @ iiap. ernet. in. † e mail: vinod@iiap.ernet.in. Abstract. We study the relaxation of a compressible plasma to ...

  15. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies...

  16. Baryogenesis via Elementary Goldstone Higgs Relaxation

    DEFF Research Database (Denmark)

    Gertov, Helene; Pearce, Lauren; Sannino, Francesco

    2016-01-01

    We extend the relaxation mechanism to the Elementary Goldstone Higgs framework. Besides studying the allowed parameter space of the theory we add the minimal ingredients needed for the framework to be phenomenologically viable. The very nature of the extended Higgs sector allows to consider very ...... but radiatively generated, it is possible to generate the observed matter-antimatter asymmetry via the relaxation mechanism....

  17. Relaxation dynamics following transition of solvated electrons

    International Nuclear Information System (INIS)

    Barnett, R.B.; Landman, U.; Nitzan, A.

    1989-01-01

    Relaxation dynamics following an electronic transition of an excess solvated electron in clusters and in bulk water is studied using an adiabatic simulation method. In this method the solvent evolves classically and the electron is constrained to a specified state. The coupling between the solvent and the excess electron is evaluated via the quantum expectation value of the electron--water molecule interaction potential. The relaxation following excitation (or deexcitation) is characterized by two time scales: (i) a very fast (/similar to/20--30 fs) one associated with molecular rotations in the first solvation shell about the electron, and (ii) a slower stage (/similar to/200 fs), which is of the order of the longitudinal dielectric relaxation time. The fast relaxation stage exhibits an isotope effect. The spectroscopical consequences of the relaxation dynamics are discussed

  18. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

  19. Vibrational and Rotational Energy Relaxation in Liquids

    DEFF Research Database (Denmark)

    Petersen, Jakob

    Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...

  20. Cross-relaxation solid state lasers

    International Nuclear Information System (INIS)

    Antipenko, B.M.

    1989-01-01

    Cross-relaxation functional diagrams provide a high quantum efficiency for pumping bands of solid state laser media and a low waste heat. A large number of the cross-relaxation mechanisms for decay rare earth excited states in crystals have been investigated. These investigations have been a starting-point for development of the cross-relaxation solid state lasers. For example, the cross-relaxation interactions, have been used for the laser action development of LiYF 4 :Gd-Tb. These interactions are important elements of the functional diagrams of the 2 μm Ho-doped media sensitized with Er and Tm and the 3 μm Er-doped media. Recently, new efficient 2 μm laser media with cross-relaxation pumping diagrams have been developed. Physical aspects of these media are the subject of this paper. A new concept of the Er-doped medium, sensitized with Yb, is illustrated