Science.gov

Sample records for bound nuclear system

  1. Optical Potential Parameters of Weakly Bound Nuclear System 17F+13C

    NASA Astrophysics Data System (ADS)

    An, Guang-Peng; Lin, Cheng-Jian; Zhang, Huan-Qiao; Liu, Zu-Hua; Yang, Feng; Zhang, Gao-Long; Zhang, Chun-Lei; Wu, Zhen-Dong; Jia, Fei; Jia, Hui-Ming; Xu, Xin-Xing; Bai, Chun-Lin; Yu, Ning

    2008-12-01

    Elastic scattering angular distributions of the 14N+16O system and the angular distributions of transfer reaction 16O(14N,13 C)17 F at ELab = 76.2 MeV and 57MeV have been measured and calculated by means of the exact finite-range distorted-wave Born approximation with the PTOLEMY code. The optical potential parameters for the weakly bound nuclear system 17F+13 C have been deduced and applied to analyse the elastic scattering angular distributions of the similar systems 17F+12C and 17F+14N which are taken from literature. The result shows that the transfer reaction with stable projectile and target combination can be used as an alternative method to extract the optical potential parameters for the weakly bound nuclear system.

  2. The Quest for Pionic and Kaonic Nuclear Bound Systems Following Yukawa and Tomonaga

    NASA Astrophysics Data System (ADS)

    Yamazaki, T.

    After sketching some historical events related to Yukawa and Tomonagaconcerning the birth of mesons, the author describes recent developments in the spectroscopy of pion-nucleus bound states via ``pion-transfer" reactions. The role of pions as Nambu-Goldstone bosons in nuclear media is emphasized by recently obtained experimental evidence for the partial restoration of chiral symmetry breaking. New light is shed on bar{K} mesons, which play a unique role in forming dense nuclear systems. The basic unit, K^-pp, is predicted to possess a molecular structure with quasi-Λ(1405) as an ``atomic constituent". We find here super strong nuclear force produced by a migrating real bar{K} meson in the Heitler-London-Heisenberg scheme in place of the normal nuclear force mediated by Yukawa's virtual mesons.

  3. Bound and unbound nuclear systems at the drip lines: a one-dimensional model

    NASA Astrophysics Data System (ADS)

    Moschini, L.; Pérez-Bernal, F.; Vitturi, A.

    2016-08-01

    We construct a one-dimensional toy model to describe the main features of Borromean nuclei at the continuum threshold. The model consists of a core and two valence neutrons, unbound in the mean potential, that are bound by a residual point contact density-dependent interaction. Different discretization procedures are used (harmonic oscillator and transformed harmonic oscillator bases, or use of large rigid wall box). Resulting energies and wave functions, as well as inelastic transition intensities, are compared within the different discretization techniques, as well as with the exact results in the case of one particle and with the results of the di-neutron cluster model in the two particles case. Despite its simplicity, this model includes the main physical features of the structure of Borromean nuclei in an intuitive and computationally affordable framework, and will be extended to direct reaction calculations.

  4. Treatment of continuum in nuclear reactions involving weakly bound systems. A simple model to test different prescriptions describing the coupling to continuum states

    SciTech Connect

    Dasso, C. H.; Vitturi, A.

    2009-03-04

    We exploit a model describing the break-up of weakly-bound nuclei that can be used as a laboratory for testing different prescriptions that have been advanced in the literature to take into account the near-by presence of continuum states. In the model we follow the evolution of a single particle wave function in one dimension, initially bound by a Woods-Saxon type potential and then perturbed by a time- and position-dependent external field. Proper choices of this potential can simulate the effect of the interaction between reaction partners in a nuclear collision. These processes generate inelastic excitation probabilities that--distributed over the bound and continuum states of the system--lead to either a partial or a total fragmentation of the final wave function. The comparison with the exact calculations shows that standard coupled channel descriptions based on discretization of the continuum can be accurate only when a proper choice is made of the number of discrete states, of the energy mesh and of the energy cutoff. This may imply, even in simplified cases, the use of a rather large (and unpracticable) number of channels. The use of a more restricted number of channels may lead to misleading results.

  5. Endurance bounds of aerial systems

    NASA Astrophysics Data System (ADS)

    Harrington, Aaron M.; Kroninger, Christopher M.

    2014-06-01

    Within the past few years micro aerial vehicles (MAVs) have received much more attention and are starting to proliferate into military as well as civilian roles. However, one of the major drawbacks for this technology currently, has been their poor endurance, usually below 10 minutes. This is a direct result of the inefficiencies inherent in their design. Often times, designers do not consider the various components in the vehicle design and match their performance to the desired mission for the vehicle. These vehicles lack a prescribed set of design guidelines or empirically derived design equations which often limits their design to selection of commercial off-the-shelf components without proper consideration of their affect on vehicle performance. In the current study, the design space for different vehicle configurations has been examined including insect flapping, avian flapping, rotary wing, and fixed wing, and their performance bounds are established. The propulsion system typical of a rotary wing vehicle is analyzed to establish current baselines for efficiency of vehicles at this scale. The power draw from communications is analyzed to determine its impact on vehicle performance. Finally, a representative fixed wing MAV is examined and the effects of adaptive structures as a means for increasing vehicle endurance and range are examined. This paper seeks to establish the performance bounds for micro air vehicles and establish a path forward for future designs so that efficiency may be maximized.

  6. Lower bound of concurrence for qubit systems

    NASA Astrophysics Data System (ADS)

    Zhu, Xue-Na; Fei, Shao-Ming

    2013-11-01

    We study the concurrence of four-qubit quantum states and provide analytical lower bounds of concurrence in terms of the monogamy inequality of concurrence for qubit systems. It is shown that these lower bounds are able to improve the existing bounds and detect entanglement better. The approach is generalized to arbitrary qubit systems.

  7. Match-bounded String Rewriting Systems

    NASA Technical Reports Server (NTRS)

    Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2003-01-01

    We introduce a new class of automated proof methods for the termination of rewriting systems on strings. The basis of all these methods is to show that rewriting preserves regular languages. To this end, letters are annotated with natural numbers, called match heights. If the minimal height of all positions in a redex is h+1 then every position in the reduct will get height h+1. In a match-bounded system, match heights are globally bounded. Using recent results on deleting systems, we prove that rewriting by a match-bounded system preserves regular languages. Hence it is decidable whether a given rewriting system has a given match bound. We also provide a sufficient criterion for the abence of a match-bound. The problem of existence of a match-bound is still open. Match-boundedness for all strings can be used as an automated criterion for termination, for match-bounded systems are terminating. This criterion can be strengthened by requiring match-boundedness only for a restricted set of strings, for instance the set of right hand sides of forward closures.

  8. TFIIIC Bound DNA Elements in Nuclear Organization and Insulation

    PubMed Central

    Kirkland, Jacob G.; Raab, Jesse R.

    2012-01-01

    tRNA genes (tDNAs) have been known to have barrier insulator function in budding yeast, Saccharomyces cerevisiae, for over a decade. tDNAs also play a role in genome organization by clustering at sites in the nucleus and both of these functions are dependent on the transcription factor TFIIIC. More recently TFIIIC bound sites devoid of pol III, termed Extra-TFIIIC sites (ETC) have been identified in budding yeast and these sites also function as insulators and affect genome organization. Subsequent studies in Schizosaccharomyces pombe showed that TFIIIC bound sites were insulators and also functioned as Chromosome Organization Clamps (COC); tethering the sites to the nuclear periphery. Very recently studies have moved to mammalian systems where pol III genes and their associated factors have been investigated in both mouse and human cells. Short Interspersed Nuclear Elements (SINEs) that bind TFIIIC, function as insulator elements and tDNAs can also function as both enhancer -blocking and barrier insulators in these organisms. It was also recently shown that tDNAs cluster with other tDNAs and with ETCs but not with pol II transcribed genes. Intriguingly, TFIIIC is often found near pol II transcription start sites and it remains unclear what the consequences of TFIIIC based genomic organization are and what influence pol III factors have on pol II transcribed genes and vise versa. In this review we provide a comprehensive overview of the known data on pol III factors in insulation and genome organization and identify the many open questions that require further investigation. \\ PMID:23000638

  9. Identifying and bounding uncertainties in nuclear reactor thermal power calculations

    SciTech Connect

    Phillips, J.; Hauser, E.; Estrada, H.

    2012-07-01

    Determination of the thermal power generated in the reactor core of a nuclear power plant is a critical element in the safe and economic operation of the plant. Direct measurement of the reactor core thermal power is made using neutron flux instrumentation; however, this instrumentation requires frequent calibration due to changes in the measured flux caused by fuel burn-up, flux pattern changes, and instrumentation drift. To calibrate the nuclear instruments, steam plant calorimetry, a process of performing a heat balance around the nuclear steam supply system, is used. There are four basic elements involved in the calculation of thermal power based on steam plant calorimetry: The mass flow of the feedwater from the power conversion system, the specific enthalpy of that feedwater, the specific enthalpy of the steam delivered to the power conversion system, and other cycle gains and losses. Of these elements, the accuracy of the feedwater mass flow and the feedwater enthalpy, as determined from its temperature and pressure, are typically the largest contributors to the calorimetric calculation uncertainty. Historically, plants have been required to include a margin of 2% in the calculation of the reactor thermal power for the licensed maximum plant output to account for instrumentation uncertainty. The margin is intended to ensure a cushion between operating power and the power for which safety analyses are performed. Use of approved chordal ultrasonic transit-time technology to make the feedwater flow and temperature measurements (in place of traditional differential-pressure- based instruments and resistance temperature detectors [RTDs]) allows for nuclear plant thermal power calculations accurate to 0.3%-0.4% of plant rated power. This improvement in measurement accuracy has allowed many plant operators in the U.S. and around the world to increase plant power output through Measurement Uncertainty Recapture (MUR) up-rates of up to 1.7% of rated power, while also

  10. Calculations of K- nuclear quasi-bound states based on chiral meson-baryon amplitudes

    NASA Astrophysics Data System (ADS)

    Gazda, Daniel; Mareš, Jiří

    2012-05-01

    In-medium K¯N scattering amplitudes developed within a new chirally motivated coupled-channel model due to Cieplý and Smejkal that fits the recent SIDDHARTA kaonic hydrogen 1s level shift and width are used to construct K- nuclear potentials for calculations of K- nuclear quasi-bound states. The strong energy and density dependence of scattering amplitudes at and near threshold leads to K- potential depths -Re VK≈80-120 MeV. Self-consistent calculations of all K- nuclear quasi-bound states, including excited states, are reported. Model dependence, polarization effects, the role of p-wave interactions, and two-nucleon K-NN→YN absorption modes are discussed. The K- absorption widths ΓK are comparable or even larger than the corresponding binding energies BK for allK- nuclear quasi-bound states, exceeding considerably the level spacing. This discourages search for K- nuclear quasi-bound states in any but the lightest nuclear systems.

  11. Pair condensation and bound states in fermionic systems

    SciTech Connect

    Sedrakian, Armen; Clark, John W.

    2006-03-15

    We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T{sub c2} for the superfluid phase transition and the limiting temperature T{sub c3} for the extinction of trimers. The phase diagram features a Cooper-pair condensate in the high-density, low-temperature domain which, with decreasing density, crosses over to a Bose condensate of strongly bound dimers. The high-temperature, low-density domain is populated by trimers whose binding energy decreases toward the density-temperature domain occupied by the superfluid and vanishes at a critical temperature T{sub c3}>T{sub c2}.

  12. Landauer bound for analog computing systems.

    PubMed

    Diamantini, M Cristina; Gammaitoni, Luca; Trugenberger, Carlo A

    2016-07-01

    By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy. PMID:27575108

  13. Computer simulation of bounded plasma systems

    SciTech Connect

    Lawson, W.S.

    1987-03-05

    The physical and numerical problems of kinetic simulation of a bounded electrostatic plasma system in one planar dimension are examined, and solutions to them are presented. These problems include particle absorption, reflection and emission at boundaries, the solution of Poisson's equation under non-periodic boundary conditions, and the treatment of an external circuit connecting the boundaries. Some comments are also made regarding the problems of higher dimensions. The methods which are described here are implemented in a code named PDW1, which is available from Professor C.K. Birdsall, Plasma Theory and Simulation Group, Cory Hall, University of California, Berkeley, CA 94720.

  14. Wave model for conservative bound systems.

    PubMed

    Popa, Alexandru

    2005-06-22

    In the hidden variable theory, Bohm proved a connection between the Schrodinger and Hamilton-Jacobi equations and showed the existence of classical paths, for which the generalized Bohr quantization condition is valid. In this paper we prove similar properties, starting from the equivalence between the Schrodinger and wave equations in the case of the conservative bound systems. Our approach is based on the equations and postulates of quantum mechanics without using any additional postulate. Like in the hidden variable theory, the above properties are proven without using the approximation of geometrical optics or the semiclassical approximation. Since the classical paths have only a mathematical significance in our analysis, our approach is consistent with the postulates of quantum mechanics. PMID:16035787

  15. BOUNDED MINIMUM INHERENT AVAILABILITY REQUIREMENTS FOR THE SYSTEM DESCRIPTION DOCUMENTS

    SciTech Connect

    L. Booth

    1998-03-13

    The purpose of this analysis is to establish bounded minimum inherent availability requirements for the Mined Geologic Disposal System (MGDS) System Description Documents (SDDs). The purpose of the bounded minimum inherent availability is to provide a lower bound on availability which will allow design to meet throughput requirements while not affecting the ability of the items to perform their intended safety function.

  16. Role of nuclear couplings in the inelastic excitation of weakly-bound neutron-rich nuclei

    SciTech Connect

    Dasso, C.H.; Lenzi, S.M.; Vitturi, A.

    1996-12-31

    Much effort is presently devoted to the study of nuclear systems far from the stability line. Particular emphasis has been placed in light systems such as {sup 11}Li, {sup 8}B and others, where the very small binding energy of the last particles causes their density distribution to extend considerably outside of the remaining nuclear core. Some of the properties associated with this feature are expected to characterize also heavier systems in the vicinity of the proton or neutron drip lines. It is by now well established that low-lying concentrations of multipole strength arise from pure configurations in which a peculiar matching between the wavelength of the continuum wavefunction of the particles and the range of the weakly-bound hole states occurs. To this end the authors consider the break-up of a weakly-bound system in a heavy-ion collision and focus attention in the inelastic excitation of the low-lying part of the continuum. They make use of the fact that previous investigations have shown that the multipole response in this region is not of a collective nature and describe their excited states as pure particle-hole configurations. Since the relevant parameter determining the strength distributions is the binding energy of the last bound orbital they find it most convenient to use single-particle wavefunctions generated by a sperical square-well potential with characteristic nuclear dimensions and whose depth has been adjusted to give rise to a situation in which the last occupied neutron orbital is loosely-bound. Spin-orbit couplings are, for the present purpose, ignored. The results of this investigation clearly indicate that nuclear couplings have the predominant role in causing projectile dissociation in many circumstances, even at bombarding energies remarkably below the Coulomb barrier.

  17. Dynamic nuclear polarization of nucleic acid with endogenously bound manganese.

    PubMed

    Wenk, Patricia; Kaushik, Monu; Richter, Diane; Vogel, Marc; Suess, Beatrix; Corzilius, Björn

    2015-09-01

    We report the direct dynamic nuclear polarization (DNP) of (13)C nuclei of a uniformly [(13)C,(15)N]-labeled, paramagnetic full-length hammerhead ribozyme (HHRz) complex with Mn(2+) where the enhanced polarization is fully provided by the endogenously bound metal ion and no exogenous polarizing agent is added. A (13)C enhancement factor of ε = 8 was observed by intra-complex DNP at 9.4 T. In contrast, "conventional" indirect and direct DNP experiments were performed using AMUPol as polarizing agent where we obtained a (1)H enhancement factor of ε ≈ 250. Comparison with the diamagnetic (Mg(2+)) HHRz complex shows that the presence of Mn(2+) only marginally influences the (DNP-enhanced) NMR properties of the RNA. Furthermore two-dimensional correlation spectra ((15)N-(13)C and (13)C-(13)C) reveal structural inhomogeneity in the frozen, amorphous state indicating the coexistence of several conformational states. These demonstrations of intra-complex DNP using an endogenous metal ion as well as DNP-enhanced MAS NMR of RNA in general yield important information for the development of new methods in structural biology. PMID:26219517

  18. Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

    PubMed

    Nefiodov, A V; Plunien, G; Soff, G

    2002-08-19

    The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions. PMID:12190457

  19. Breakup of loosely bound nuclei at intermediate energies for nuclear astrophysics and the development of a position sensitive microstrip detector system and its readout electronics using ASICs technologies

    SciTech Connect

    Tribble, Robert E.; Sobotka, Lee G.; Blackmon, Jeff C.; Bertulani, Carlos A.

    2015-12-29

    The work performed under this grant has led to the development of a detection system that will be used to measure reaction rates for proton or neutron capture reactions at stellar energies on radioactive ions far from stability. The reaction rates are needed to better understand the physics of nucleosynthesis in explosive stellar processes such as supernovae and x-ray burst events. The radioactive ions will be produced at the Radioactive Ion Beam Facility (RIBF) at RIKEN near Tokyo, Japan. During the course of this work, the group involved in this project has expanded by several institutions in Europe and Japan and now involves collaborators from the U.S., Japan, Hungary, Romania, Germany, Spain, Italy, China, and South Korea. As part of the project, a novel design based on large-area silicon detectors has been built and tested and the performance characterized in a series of tests using particle beams with a variety of atomic numbers at the Cyclotron Institute of Texas A&M University and the Heavy Ion Medical Accelerator in Chiba facility (HIMAC) in Chiba, Japan. The work has involved mechanical construction of a special purpose vacuum chamber, with a precision mounting system for the silicon detectors, development of a new ASICs readout system that has applications with a wide variety of silicon detector systems, and the development of a data acquisition system that is integrated into the computer system being used at RIBF. The parts noted above that are needed to carry out the research program are completed and ready for installation. Several approved experiments that will use this system will be carried out in the near future. The experimental work has been delayed due to a large increase in the cost and availability of electrical power for RIBF that occurred following the massive earthquake and tsunami that hit Japan in the spring of 2011. Another component of the research carried out with this grant involved developing the theoretical tools that are required

  20. A Lower Bound of Quantum Discord for 2-Qutrit Systems

    NASA Astrophysics Data System (ADS)

    Zhang, Qianhui; Wang, Jing; Shen, Shuqian; Li, Ming

    2016-04-01

    We study the lower bound of quantum discord for 2-qutrit systems. By computing the mutual information and the classical correlations of a class of states for 2-qutrit system, an analytical and computable lower bound of discord has been derived. By selecting different coefficients as examples, we can compute the lower bound of discord for 2-qutrit systems directly. The result can be generalized to the case of high-dimensional quantum state and will help us understand and explore the discord of the high-dimensional state.

  1. Symmetry and boundness of four-particle coulomb systems

    SciTech Connect

    Rebane, T. K.

    2012-04-15

    The problem of boundness of a{sup +}b{sup +}c{sup -}d{sup -} four-particle Coulomb systems (quadrions) is studied versus the masses of the particles involved. Inequalities that make it possible to deduce that, if some reference quadrions form a bound state, the same is true for a large number of quadrions formed by particles having various masses were derived. A compendium of calculations for energies of reference systems that possess various symmetries [positronium molecules (e{sup +}e{sup +}e{sup -}e{sup -}) and quadrions of the a{sup +}b{sup +}b{sup -}b{sup -}, a{sup +}b{sup +}a{sup --}, and a{sup +}a{sup +}b{sup -}c{sup -} types] is given, and groups of bound asymmetric quadrions corresponding to them are determined. An inequality for kinetic energies of particles that makes it possible to find out, by using asymmetric reference systems, whether specific quadrions are bound is obtained. It is shown that the boundness of many quadrions is ensured by the boundness of respective three-particle systems. The entire body of the present results permits proving that, of the total number of 406 quadrions containing electrons, muons, pions, kaons, protons, deuterons, and tritons and their antiparticles, 227 quadrions are bound.

  2. Quantum Bound States in a C-C60 System

    NASA Astrophysics Data System (ADS)

    Adam, R. M.; Sofianos, S. A.

    2015-03-01

    We investigate the quantum mechanical system of a carbon "test atom" in the proximity of a C60 molecule, both inside and outside the fullerene "cage". Two sets of bound states are found to exist, a deeply bound set inside the cage and another weakly bound set outside it. Tunnelling between these regions is highly unlikely to happen because of the extreme height and width of the potential barrier. However, we predict that a layer of atoms could be adsorbed onto C60 by forming a quantum mechanical bound state, with the adsorbed atoms being concentrated above the "panels" of the buckyball, consistent with "bucky onions" observed experimentally. Until now analysis of such fullerene systems has been via classical mechanics, but a quantum approach reveals new insights.

  3. Deuterium nuclear magnetic resonance unambiguously quantifies pore and collagen-bound water in cortical bone

    PubMed Central

    Ong, Henry H.; Wright, Alexander C.; Wehrli, Felix W.

    2012-01-01

    Bone water (BW) plays a pivotal role in nutrient transport and conferring bone with its viscoelastic mechanical properties. BW is partitioned between the pore spaces of the Haversian and lacuno-canalicular system, and water predominantly bound to the matrix proteins (essentially collagen). The general model of BW is that the former predominantly experiences fast isotropic molecular reorientation, whereas water in the bone matrix undergoes slower anisotropic rotational diffusion. Here, we provide direct evidence for the correctness of this model and show that unambiguous quantification in situ of these two functionally and dynamically different BW fractions is possible. The approach chosen relies on nuclear magnetic resonance (NMR) of deuterium (2H) that unambiguously separates and quantifies the two fractions on the basis of their distinguishing microdynamic properties. Twenty-four specimens of the human tibial cortex from six donors (3 male, 3 female, ages 27-83 years) were cored and 2H spectra recorded at 62 MHz (9.4 Tesla) on a Bruker Instruments DMX 400 spectrometer after exchange of native BW with 2H2O. Spectra consisted of a doublet signal resulting from quadrupole interaction of water bound to collagen. Doublet splittings were found to depend on the orientation of the osteonal axis with respect to the magnetic field direction (8.2 and 4.3 kHz for parallel and perpendicular orientation, respectively). In contrast, the isotropically reorienting pore-resident water yielded a single resonance line superimposed on the doublet. Nulling of the singlet resonance allowed separation of the two fractions. The results indicate that in human cortical bone 60-80% of detectable BW is collagen-bound. Porosity determined as the difference between total BW and collagen bound water fraction was found to strongly parallel μCT based measurements (R2 = 0.91). Our method provides means for direct validation of emerging relaxation-based measurements of cortical bone porosity by

  4. Computation in Dynamically Bounded Asymmetric Systems

    PubMed Central

    Rutishauser, Ueli; Slotine, Jean-Jacques; Douglas, Rodney

    2015-01-01

    Previous explanations of computations performed by recurrent networks have focused on symmetrically connected saturating neurons and their convergence toward attractors. Here we analyze the behavior of asymmetrical connected networks of linear threshold neurons, whose positive response is unbounded. We show that, for a wide range of parameters, this asymmetry brings interesting and computationally useful dynamical properties. When driven by input, the network explores potential solutions through highly unstable ‘expansion’ dynamics. This expansion is steered and constrained by negative divergence of the dynamics, which ensures that the dimensionality of the solution space continues to reduce until an acceptable solution manifold is reached. Then the system contracts stably on this manifold towards its final solution trajectory. The unstable positive feedback and cross inhibition that underlie expansion and divergence are common motifs in molecular and neuronal networks. Therefore we propose that very simple organizational constraints that combine these motifs can lead to spontaneous computation and so to the spontaneous modification of entropy that is characteristic of living systems. PMID:25617645

  5. Bound Nucleon Form Factors, Quark-Hadron Duality, and the Nuclear EMC Effect

    SciTech Connect

    K. Tsushima; D.H. Lu; W. Melnitchouk; K. Saito; A.W. Thomas

    2002-09-13

    We discuss the electromagnetic form factors, axial form factors, and structure functions of a nucleon bound in the quark-meson coupling (QMC) model. Free space nucleon form factors are calculated using the improved cloudy bag model (ICBM). After describing finite nuclei and nuclear matter in the quark-based (EMC) model, the in-medium modification of the bound nucleon form factors is calculated in the same model. Finally, the bound nucleon structure function, F2, is extracted using the calculated in-medium electromagnetic form factors and Bloom-Gilman (quark-hadron) duality.

  6. Modulatory Effect of Taurine on 7,12-Dimethylbenz(a)Anthracene-Induced Alterations in Detoxification Enzyme System, Membrane Bound Enzymes, Glycoprotein Profile and Proliferative Cell Nuclear Antigen in Rat Breast Tissue.

    PubMed

    Vanitha, Manickam Kalappan; Baskaran, Kuppusamy; Periyasamy, Kuppusamy; Selvaraj, Sundaramoorthy; Ilakkia, Aruldoss; Saravanan, Dhiravidamani; Venkateswari, Ramachandran; Revathi Mani, Balasundaram; Anandakumar, Pandi; Sakthisekaran, Dhanapal

    2016-08-01

    The modulatory effect of taurine on 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast cancer in rats was studied. DMBA (25 mg/kg body weight) was administered to induce breast cancer in rats. Protein carbonyl levels, activities of membrane bound enzymes (Na(+) /K(+) ATPase, Ca(2+) ATPase, and Mg(2+) ATPase), phase I drug metabolizing enzymes (cytochrome P450, cytochrome b5, NADPH cytochrome c reductase), phase II drug metabolizing enzymes (glutathione-S-transferase and UDP-glucuronyl transferase), glycoprotein levels, and proliferative cell nuclear antigen (PCNA) were studied. DMBA-induced breast tumor bearing rats showed abnormal alterations in the levels of protein carbonyls, activities of membrane bound enzymes, drug metabolizing enzymes, glycoprotein levels, and PCNA protein expression levels. Taurine treatment (100 mg/kg body weight) appreciably counteracted all the above changes induced by DMBA. Histological examination of breast tissue further supported our biochemical findings. The results of the present study clearly demonstrated the chemotherapeutic effect of taurine in DMBA-induced breast cancer. PMID:27091720

  7. Space nuclear power systems

    NASA Technical Reports Server (NTRS)

    Carpenter, R. T.

    1972-01-01

    Space nuclear power systems are considered for use in those particular spacecraft applications for which nuclear power systems offer unique advantages over solar and/or chemical space power systems. Both isotopic and reactor heated space electrical power units are described in an attempt to illustrate their operating characteristics, spacecraft integration aspects, and factory-to-end of mission operational considerations. The status of technology developments in nuclear power systems is presented. Some projections of those technologies are made to form a basis for the applications of space nuclear power systems to be expected over the next 10-15 years.

  8. NUCLEAR REACTOR CONTROL SYSTEM

    DOEpatents

    Epler, E.P.; Hanauer, S.H.; Oakes, L.C.

    1959-11-01

    A control system is described for a nuclear reactor using enriched uranium fuel of the type of the swimming pool and other heterogeneous nuclear reactors. Circuits are included for automatically removing and inserting the control rods during the course of normal operation. Appropriate safety circuits close down the nuclear reactor in the event of emergency.

  9. Structure of classical trajectories in multidimensional bound molecular systems

    SciTech Connect

    Ashton, C.J.; Muckerman, J.T.

    1983-07-21

    A computational method is described which enables visualization of the coordinate space envelopes of classical trajectories in multidimensional bound molecular systems. The method is exemplified by application to a realistic three-dimensional model of the vibrating water molecule, and its utility in the application of semiclassical quantization techniques is emphasized. 8 figures.

  10. MPC for LPV systems with bounded parameter variations

    NASA Astrophysics Data System (ADS)

    Jungers, Marc; Oliveira, Ricardo C. L. F.; Peres, Pedro L. D.

    2011-01-01

    This article deals with the model predictive control (MPC) design problem for systems which are linearly dependent on a time-varying parameter. The main novelty is that, motivated by practical issues, the bounds on the rate of variation of the parameters are taken into account in the control design. Moreover, a Lyapunov function depending multiaffinely on the parameters computed at a set of instants of time and a parameter-dependent control gain are used to provide an upper bound to a quadratic performance index. The solution is obtained by means of a semidefinite programming algorithm. Examples illustrate the efficiency of the proposed approach.

  11. 21 CFR 862.1640 - Protein-bound iodine test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Protein-bound iodine test system. 862.1640 Section... Systems § 862.1640 Protein-bound iodine test system. (a) Identification. A protein-bound iodine test system is a device intended to measure protein-bound iodine in serum. Measurements of...

  12. 21 CFR 862.1640 - Protein-bound iodine test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Protein-bound iodine test system. 862.1640 Section... Systems § 862.1640 Protein-bound iodine test system. (a) Identification. A protein-bound iodine test system is a device intended to measure protein-bound iodine in serum. Measurements of...

  13. 21 CFR 862.1640 - Protein-bound iodine test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Protein-bound iodine test system. 862.1640 Section... Systems § 862.1640 Protein-bound iodine test system. (a) Identification. A protein-bound iodine test system is a device intended to measure protein-bound iodine in serum. Measurements of...

  14. 21 CFR 862.1640 - Protein-bound iodine test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Protein-bound iodine test system. 862.1640 Section... Systems § 862.1640 Protein-bound iodine test system. (a) Identification. A protein-bound iodine test system is a device intended to measure protein-bound iodine in serum. Measurements of...

  15. 21 CFR 862.1640 - Protein-bound iodine test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Protein-bound iodine test system. 862.1640 Section... Systems § 862.1640 Protein-bound iodine test system. (a) Identification. A protein-bound iodine test system is a device intended to measure protein-bound iodine in serum. Measurements of...

  16. Adiabatic hyperspherical study of weakly bound He(2)H(-), He(2)H, and HeH(2) systems.

    PubMed

    Suno, Hiroya

    2010-06-14

    The He(2)H(-), He(2)H, and HeH(2) triatomic systems are studied using the adiabatic hyperspherical representation. By adopting the best empirical interaction potentials, we search for weakly bound states of (4)He(2) H(-), (4)He(2) H, and (4)HeH(2). We consider not only zero total nuclear orbital angular momentum, J=0, states but also J>0 states. We find no bound state for the (4)He(2) H systems, while the (4)He(2) H(-) and (4)HeH(2) systems are shown to possess three and one bound states, respectively, for J(Pi)=0(+). Interestingly, one bound state has been found each for the J(Pi)=1(-) and 2(+) symmetries of the (4)He(2) H(-) anion. We shall calculate the bound state energies and analyze the molecular structure of these species in detail. PMID:20550401

  17. Muonic bound systems, virtual particles, and proton radius

    NASA Astrophysics Data System (ADS)

    Jentschura, U. D.

    2015-07-01

    The proton radius puzzle questions the self-consistency of theory and experiment in light muonic and electronic bound systems. Here we summarize the current status of virtual particle models as well as Lorentz-violating models that have been proposed in order to explain the discrepancy. Highly charged one-electron ions and muonic bound systems have been used as probes of the strongest electromagnetic fields achievable in the laboratory. The average electric field seen by a muon orbiting a proton is comparable to hydrogenlike uranium and, notably, larger than the electric field in the most advanced strong-laser facilities. Effective interactions due to virtual annihilation inside the proton (lepton pairs) and process-dependent corrections (nonresonant effects) are discussed as possible explanations of the proton size puzzle. The need for more experimental data on related transitions is emphasized.

  18. Time optimal feedback control of discrete systems with bounded inputs

    NASA Technical Reports Server (NTRS)

    Chen, Xin; Longman, Richard W.; Klein, George

    1990-01-01

    Deadbeat control theory gives a feedback solution to the time optimal control of discrete time systems. Experience has shown the results to be impractical because they ignore bounds on the actuator strength. This paper develops two algorithms for generating time optimal control in feedback form for discrete systems with bounded controls. The results are also applicable for generating recovery regions and the set of reachable states. For multiple control problems a method of generating sublayers is developed which decreases off-line and on-line computational effort. Two algorithms are presented with somewhat different computational and storage requirements. The algorithms are practical within certain dimension constraints, and are natural for implementation with parallel processing.

  19. Multiply Strange Nuclear Systems

    NASA Astrophysics Data System (ADS)

    Schaffner, J.; Dover, C. B.; Gal, A.; Greiner, C.; Millener, D. J.; Stocker, H.

    1994-10-01

    We investigate the stability of multiply strange baryonic systems, in the context of a mean field approach obtained from an underlying set of phenomenological meson-baryon interactions. The coupling parameters which determine the conventional σ + ω mean fields (Hartree potentials) seen by various baryon species (N, Λ, Ξ) in the many-body system are constrained by reproducing the trend of observed binding energies of single particle (N, Λ, Ξ) states, as well as the energy per particle and density of non-strange nuclear matter. We also consider additional scalar (σ*) and vector (φ) fields which couple strongly to strange baryons. The couplings of these fields are adjusted to produce strong hyperon-hyperon interactions, as suggested by the data on ΛΛ hypernuclei. Extrapolating this approach to systems of large strangeness S, we find a broad class of objects composed of neutrons, protons, Λ‧s and Ξ‧s, which are stable against strong decay. In these systems, the presence of filled Λ orbitals blocks the strong decay ΞN → ΛΛ, leading to a strangeness fraction fs = |S|/A ≍1, density ρ ≍ (2 - 3) ρ0, and charge fraction fq in the range - 0.1 bound multi-strange objects can be stable for very large A, unlike ordinary nuclei, since the Coulomb repulsion generated by the protons is largely cancelled by the presence of a comparable number of Ξ‧s, leading to a small net charge (positive or negative) of order A1/3. We comment on the weak decays of such subjects and the possibility of their production in relativistic heavy ion collisions.

  20. Bounded-time fault-tolerant rule-based systems

    NASA Technical Reports Server (NTRS)

    Browne, James C.; Emerson, Allen; Gouda, Mohamed; Miranker, Daniel; Mok, Aloysius; Rosier, Louis

    1990-01-01

    Two systems concepts are introduced: bounded response-time and self-stabilization in the context of rule-based programs. These concepts are essential for the design of rule-based programs which must be highly fault tolerant and perform in a real time environment. The mechanical analysis of programs for these two properties is discussed. The techniques are used to analyze a NASA application.

  1. Lower bounds on the computational efficiency of optical computing systems

    NASA Astrophysics Data System (ADS)

    Barakat, Richard; Reif, John

    1987-03-01

    A general model for determining the computational efficiency of optical computing systems, termed the VLSIO model, is described. It is a 3-dimensional generalization of the wire model of a 2-dimensional VLSI with optical beams (via Gabor's theorem) replacing the wires as communication channels. Lower bounds (in terms of simultaneous volume and time) on the computational resources of the VLSIO are obtained for computing various problems such as matrix multiplication.

  2. Control of Rate-Bounded Hybrid Systems with Liveness Specifications

    NASA Technical Reports Server (NTRS)

    Heymann, Michael; Lin, Feng; Meyer, George

    1998-01-01

    In the present paper we examine the control problem for a class of composite hybrid machines (CHMs) that consist of concurrent operation (employing synchronous composition) of elementary hybrid machines (EHMs), that allows both signal sharing and event synchronization. A controller can then be coupled with the plant by means of synchronous composition. We confine our attention to controllers that interact with the system only through event synchronization. We present an initial investigation of synthesis of liveness controllers for hybrid machines. To this end we define open hybrid machines as systems that can interact with the environment through event synchronization and can be therefor be "driven" to their marked configuration by user (controller). Liveness specifications must be associated with timing constraints. We may require that for a specified time limit, every run reach a marked configuration within that time limit. Alternatively, a more relaxed specification may be that, for some (unspecified) global time bound, every run of the system reach a marked configuration within that time bound. Finally, the least restrictive liveness requirement is that every run reach a marked configuration within a finite time limit (but we do not insist on the existence of a global time bound for all runs).

  3. Examination of quantized multiskyrmions as possible nuclear bound states of antikaons

    SciTech Connect

    Kopeliovich, Vladimir; Potashnikova, Irina

    2011-06-15

    The spectrum of strange multibaryons (baryon number B=2 and 3) is considered within the chiral soliton model using one of several possible SU(3) quantization models (the bound state rigid oscillator version). The states with energy below that of an antikaon and its corresponding nucleus can be interpreted as antikaon-nucleus bound states. In the formal limit of small kaon mass the number of such states becomes large, and for a real value of this mass there are at least several states with positive and negative parity in the energy gap of one kaon mass. For large values of binding energies the interpretation of such states as just antikaon-nuclear bound states becomes more ambiguous.

  4. Probing infinity in bounded two-dimensional electrostatic systems.

    PubMed

    Abutalib, M; Batle, J; Ooi, C H Raymond

    2016-07-01

    The total electrostatic energy of systems of identical particles of equal charge is studied in configurations bounded in space, but divergent in the number of charges. This approach shall guide us to unveil a non-linear, functional form specifying the divergent nature of system energy. We consider fractals to be physical entities, with charges located in their vertices or nodes. This description is interesting since features, such as the corresponding fractal dimension, can characterize the total energy EN. Finally, at local length scales, we describe how energy diverges at charge accumulation points in the fractal, that is, almost everywhere by definition. PMID:27475073

  5. Probing infinity in bounded two-dimensional electrostatic systems

    NASA Astrophysics Data System (ADS)

    Abutalib, M.; Batle, J.; Ooi, C. H. Raymond

    2016-07-01

    The total electrostatic energy of systems of identical particles of equal charge is studied in configurations bounded in space, but divergent in the number of charges. This approach shall guide us to unveil a non-linear, functional form specifying the divergent nature of system energy. We consider fractals to be physical entities, with charges located in their vertices or nodes. This description is interesting since features, such as the corresponding fractal dimension, can characterize the total energy EN. Finally, at local length scales, we describe how energy diverges at charge accumulation points in the fractal, that is, almost everywhere by definition.

  6. Mission Availability for Bounded-Cumulative-Downtime System

    PubMed Central

    Zhou, Yu; Kou, Gang; Ergu, Daji; Peng, Yi

    2013-01-01

    In this research, a mathematics model is proposed to describe the mission availability for bounded-cumulative-downtime system. In the proposed model, the cumulative downtime and cumulative uptime are considered as constraints simultaneously. The mission availability can be defined as the probability that all repairs do not exceed the bounded cumulative downtime constraint of such system before the cumulative uptime has accrued. There are two mutually exclusive cases associated with the probability. One case is the system has not failed, where the probability can be described by system reliability. The other case is the system has failed and the cumulative downtime does not exceed the constraint before the cumulative uptime has accrued. The mathematic description of the probability under the second case is very complex. And the cumulative downtime in a mission can be set as a random variable, whose cumulative distribution means the probability that the failure system can be restored to the operating state. Giving the dependence in the scheduled mission, a mission availability model with closed form expression under this assumption is proposed. Numerical simulations are presented to illustrate the effectiveness of the proposed model. The results indicate that the relative errors are acceptable and the proposed model is effective. Furthermore, three important applications of the proposed mission availability model are discussed. PMID:23843940

  7. Nuclear propulsion systems engineering

    SciTech Connect

    Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

    1992-12-31

    The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960`s and early 1970`s was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts.

  8. Nuclear propulsion systems engineering

    SciTech Connect

    Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

    1992-01-01

    The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960's and early 1970's was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts.

  9. A search for deeply-bound kaonic nuclear states at J-PARC

    NASA Astrophysics Data System (ADS)

    Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Fukuda, Y.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreanu, D.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Sekimoto, M.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2010-04-01

    The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K- pp, by the in-flight 3He(K-,n) reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron and the invariant mass via the expected decay, K- pp → Λp → pπ- p. In this report, an overview of the experiment and the preparation status are presented.

  10. J/{Psi} Mass Shift and J/{Psi}-Nuclear Bound State

    SciTech Connect

    Tsushima, Kazuo; Thomas, Anthony W.; Lu, D. H.; Krein, Gastao

    2011-05-24

    We calculate mass shift of the J/{Psi} meson in nuclear matter arising from the modification of DD, DD* and D*D* meson loop contributions to the J/{Psi} self-energy. The estimate includes the in-medium D and D* meson masses consistently. The J/{Psi} mass shift (scalar potential) calculated is negative (attractive), and is complementary to the attractive potential obtained from the QCD color van der Waals forces. Some results for the J/{Psi}-nuclear bound state energies are also presented.

  11. J/Ψ Mass Shift and J/Ψ-Nuclear Bound State

    NASA Astrophysics Data System (ADS)

    Tsushima, Kazuo; Lu, D. H.; Krein, Gastao; Thomas, Anthony W.

    2011-05-01

    We calculate mass shift of the J/Ψ meson in nuclear matter arising from the modification of DD, DD* and D*D* meson loop contributions to the J/Ψ self-energy. The estimate includes the in-medium D and D* meson masses consistently. The J/Ψ mass shift (scalar potential) calculated is negative (attractive), and is complementary to the attractive potential obtained from the QCD color van der Waals forces. Some results for the J/Ψ-nuclear bound state energies are also presented.

  12. Particle simulation of bounded 1D plasma systems

    SciTech Connect

    Lawson, W.S.

    1989-02-01

    The physical and numerical problems of kinetic simulation of a bounded electrostatic plasma system in one planar dimension are examined, and solutions to them are presented. These problems include particle absorption, reflection and emission at boundaries, the solution of Poisson's equation under non-periodic boundary conditions, and the treatment of an external circuit connecting the boundaries. The methods which are described here are implemented in a code named PDW1, which is available from Professor C. K. Birdsall, Plasma Theory and Simulation Group, Cory Hall, University of California, Berkeley, CA 94720. copyright 1989 Academic Press, Inc.

  13. Partical Simulation of Bounded 1D Plasma Systems

    NASA Astrophysics Data System (ADS)

    Lawson, William S.

    1989-02-01

    The physical and numerical problems of kinetic simulation of a bounded electrostatic plasma system in one planar dimension are examined, and solutions to them are presented. These problems include particle absorption, reflection and emission at boundaries, the solution of Poisson's equation under non-periodic boundary conditions, and the treatment of an external circuit connecting the boundaries. The methods which are described here are immlemented in a code named PDW1, which is available from Professor C. K. Birdsall, Plasma Theory and Simulation Group, Cory Hall, University of California, Berkeley, CA 94720.

  14. Nuclear medicine imaging system

    DOEpatents

    Bennett, G.W.; Brill, A.B.; Bizais, Y.J.C.; Rowe, R.W.; Zubal, I.G.

    1983-03-11

    It is an object of this invention to provide a nuclear imaging system having the versatility to do positron annihilation studies, rotating single or opposed camera gamma emission studies, and orthogonal gamma emission studies. It is a further object of this invention to provide an imaging system having the capability for orthogonal dual multipinhole tomography. It is another object of this invention to provide a nuclear imaging system in which all available energy data, as well as patient physiological data, are acquired simultaneously in list mode.

  15. Finite Energy and Bounded Attacks on Control System Sensor Signals

    SciTech Connect

    Djouadi, Seddik M; Melin, Alexander M; Ferragut, Erik M; Laska, Jason A

    2014-01-01

    Control system networks are increasingly being connected to enterprise level networks. These connections leave critical industrial controls systems vulnerable to cyber-attacks. Most of the effort in protecting these cyber-physical systems (CPS) has been in securing the networks using information security techniques and protection and reliability concerns at the control system level against random hardware and software failures. However, besides these failures the inability of information security techniques to protect against all intrusions means that the control system must be resilient to various signal attacks for which new analysis and detection methods need to be developed. In this paper, sensor signal attacks are analyzed for observer-based controlled systems. The threat surface for sensor signal attacks is subdivided into denial of service, finite energy, and bounded attacks. In particular, the error signals between states of attack free systems and systems subject to these attacks are quantified. Optimal sensor and actuator signal attacks for the finite and infinite horizon linear quadratic (LQ) control in terms of maximizing the corresponding cost functions are computed. The closed-loop system under optimal signal attacks are provided. Illustrative numerical examples are provided together with an application to a power network with distributed LQ controllers.

  16. The wave function and minimum uncertainty function of the bound quadratic Hamiltonian system

    NASA Technical Reports Server (NTRS)

    Yeon, Kyu Hwang; Um, Chung IN; George, T. F.

    1994-01-01

    The bound quadratic Hamiltonian system is analyzed explicitly on the basis of quantum mechanics. We have derived the invariant quantity with an auxiliary equation as the classical equation of motion. With the use of this invariant it can be determined whether or not the system is bound. In bound system we have evaluated the exact eigenfunction and minimum uncertainty function through unitary transformation.

  17. Deciding Termination for Ancestor Match- Bounded String Rewriting Systems

    NASA Technical Reports Server (NTRS)

    Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2005-01-01

    Termination of a string rewriting system can be characterized by termination on suitable recursively defined languages. This kind of termination criteria has been criticized for its lack of automation. In an earlier paper we have shown how to construct an automated termination criterion if the recursion is aligned with the rewrite relation. We have demonstrated the technique with Dershowitz's forward closure criterion. In this paper we show that a different approach is suitable when the recursion is aligned with the inverse of the rewrite relation. We apply this idea to Kurth's ancestor graphs and obtain ancestor match-bounded string rewriting systems. Termination is shown to be decidable for this class. The resulting method improves upon those based on match-boundedness or inverse match-boundedness.

  18. Search for deeply bound Kaonic nuclear states via 3He(K-, n) reaction at J-PARC

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kato, Y.; Kawasaki, S.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Lener, M. Poli; Vidal, A. Romero; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Wuenschek, B. K.; Yamaga, T.; Yamazaki, T.; Yim, H.; Zhang, Q.; Zmeskal, J.

    2015-10-01

    As the latest effort to search for deeply-bound overline K-nuclear states, E15 experiment has been carried out at K1.8 branch beam line (K1.8BR) at J-PARC. 3He(K-, N) reaction was employed to search for the simplest overline K-nuclear bound state, K--pp. In this proceeding, preliminary results of 3He(K-, n) spectra obtained in the first physics-run will be presented.

  19. A Search for Deeply Bound Kaonic Nuclear States at J-PARC

    NASA Astrophysics Data System (ADS)

    Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Lener, M. Poli; Vidal, A. Romero; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2013-08-01

    The J-PARC E15 experiment has the aims to search for the simplest kaonic nuclear bound state, K - pp, by the in-flight 3He( K -, n) reaction. The exclusive measurement is performed by a simultaneous measurement of the missing mass using the knocked out neutron and the invariant mass via the expected decay, K - pp → Λ p → pπ- p. In this paper, an overview of the experiment and current data analysis of the engineering runs performed in February and June 2012 are presented.

  20. Dynamic nuclear polarization of membrane proteins: covalently bound spin-labels at protein-protein interfaces.

    PubMed

    Wylie, Benjamin J; Dzikovski, Boris G; Pawsey, Shane; Caporini, Marc; Rosay, Melanie; Freed, Jack H; McDermott, Ann E

    2015-04-01

    We demonstrate that dynamic nuclear polarization of membrane proteins in lipid bilayers may be achieved using a novel polarizing agent: pairs of spin labels covalently bound to a protein of interest interacting at an intermolecular interaction surface. For gramicidin A, nitroxide tags attached to the N-terminal intermolecular interface region become proximal only when bimolecular channels forms in the membrane. We obtained signal enhancements of sixfold for the dimeric protein. The enhancement effect was comparable to that of a doubly tagged sample of gramicidin C, with intramolecular spin pairs. This approach could be a powerful and selective means for signal enhancement in membrane proteins, and for recognizing intermolecular interfaces. PMID:25828256

  1. Nuclear core positioning system

    DOEpatents

    Garkisch, Hans D.; Yant, Howard W.; Patterson, John F.

    1979-01-01

    A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

  2. Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.

    2012-01-01

    Fission power and propulsion systems can enable exciting space exploration missions. These include bases on the moon and Mars; and the exploration, development, and utilization of the solar system. In the near-term, fission surface power systems could provide abundant, constant, cost-effective power anywhere on the surface of the Moon or Mars, independent of available sunlight. Affordable access to Mars, the asteroid belt, or other destinations could be provided by nuclear thermal rockets. In the further term, high performance fission power supplies could enable both extremely high power levels on planetary surfaces and fission electric propulsion vehicles for rapid, efficient cargo and crew transfer. Advanced fission propulsion systems could eventually allow routine access to the entire solar system. Fission systems could also enable the utilization of resources within the solar system.

  3. Nuclear Bound States of Molecular Hydrogen Physisorbed on Graphene: An Effective Two-Dimensional Model.

    PubMed

    de Lara-Castells, María Pilar; Mitrushchenkov, Alexander O

    2015-11-01

    The interaction potential of molecular hydrogen physisorbed on a graphene sheet is evaluated using the ab initio-based periodic dlDF+Das scheme and its accuracy is assessed by comparing the nuclear bound-state energies supported by the H2(D2/HD)/graphite potentials with the experimental energies. The periodic dlDF+Das treatment uses DFT-based symmetry-adapted perturbation theory on surface cluster models to extract the dispersion contribution to the interaction whereas periodic dispersionless density functional (dlDF) calculations are performed to determine the dispersion-free counterpart. It is shown that the H2/graphene interaction is effectively two-dimensional (2D), with the distance from the molecule center-of-mass to the surface plane and the angle between the diatomic axis and the surface normal as the relevant degrees of freedom. The global potential minimum is found at the orthogonal orientation of the molecule with respect to the surface plane, with an equilibrium distance of 3.17 Å and a binding energy of -51.9 meV. The comparison of the binding energies shows an important improvement of our approach over the vdW-corrected DFT schemes when we are dealing with the very weak H2/surface interaction. Next, the 2D nuclear bound-state energies are calculated numerically. As a cross-validation of the interaction potential, the bound states are also determined for molecular hydrogen on the graphite surface (represented as an assembly of graphene sheets). With the largest absolute deviation being 1.7 meV, the theoretical and experimental energy levels compare very favorably. PMID:26479965

  4. Design procedure for satisfying time domain bounds for nonminimum-phase systems. [feedback control systems

    NASA Technical Reports Server (NTRS)

    Ostheimer, W. D.

    1972-01-01

    Design techniques are presented applicable to nonminimum-phase systems. They are designed to handle plants with one right-half-plane zero which may vary, and any other variation of the plant parameters within known limits. The specifications that must be designed are given as a set of step response bounds in the time domain. A completed design will yield responses that stay within the time domain bounds at all times and utilize the entire region of allowed variation.

  5. Nuclear and QED corrections to the bound-electron g factor

    NASA Astrophysics Data System (ADS)

    Zatorski, Jacek; Oreshkina, Natalia S.; Keitel, Christoph H.; Harman, Zoltán

    2012-06-01

    We calculate nuclear shape and quantum electrodynamic corrections to the g factor of a bound electron [1,2]. These theoretical studies are motivated by the current improvement of experimental possibilities: on the one hand, in a recent Penning trap measurement [2], the g factor of ^28Si^13+ has been determined with an unprecedented 5 .10-10 relative uncertainty. A novel experimental technique will further improve accuracy to the 10-11 level. On the other hand, experiments with ions as heavy as ^238U^91+ will be performed soon at the HITRAP-FAIR facility. For such heavy ions, nuclear effects play an important role. The leading relativistic nuclear deformation correction has been derived analytically and also its influence on one-loop quantum electrodynamic terms has been evaluated. We present results for medium- and high-Z hydrogenlike ions, which become significant already for mid-Z ions, and for very heavy elements it even reaches the 10-6 level, as we show in [1].[4pt] [1] J. Zatorski, N. S. Oreshkina, C. H. Keitel, and Z. Harman, Phys. Rev. Lett., in press; arXiv:1110.3330 [2] S. Sturm, A. Wagner, B. Schabinger, J. Zatorski, et al., Phys. Rev. Lett. 107, 023002 (2011).

  6. Nuclear power system

    SciTech Connect

    Yampolsky, J.S.; Cavallaro, L.; Paulovich, K.F.; Schleicher, R.W.

    1989-09-05

    This patent describes an inherently safe modular nuclear power system for producing electrical power at acceptable efficiency levels using working fluids at relatively low temperatures and pressures. The system comprising: a reactor module for heating a first fluid; a heat exchanger module for transferring heat from the first fluid to a second fluid; a first piping system effecting flow of the first fluid in a first fluid circuit successively through the reactor module and the heat exchanger module; a power conversion module comprising a turbogenerator driven by the second fluid, and means for cooling the second fluid upon emergence thereof from the turbogenerator; a second piping system comprising means for effecting flow of the second fluid in a second fluid circuit successively through the heat exchanger module and the power conversion module; and a plurality of pits for receiving the modules.

  7. Nuclear criticality information system

    SciTech Connect

    Koponen, B.L.; Hampel, V.E.

    1981-11-30

    The nuclear criticality safety program at LLNL began in the 1950's with a critical measurements program which produced benchmark data until the late 1960's. This same time period saw the rapid development of computer technology useful for both computer modeling of fissile systems and for computer-aided management and display of the computational benchmark data. Database management grew in importance as the amount of information increased and as experimental programs were terminated. Within the criticality safety program at LLNL we began at that time to develop a computer library of benchmark data for validation of computer codes and cross sections. As part of this effort, we prepared a computer-based bibliography of criticality measurements on relatively simple systems. However, it is only now that some of these computer-based resources can be made available to the nuclear criticality safety community at large. This technology transfer is being accomplished by the DOE Technology Information System (TIS), a dedicated, advanced information system. The NCIS database is described.

  8. Coupled Segmentation of Nuclear and Membrane-bound Macromolecules through Voting and Multiphase Level Set

    PubMed Central

    Wen, Quan

    2014-01-01

    Membrane-bound macromolecules play an important role in tissue architecture and cell-cell communication, and is regulated by almost one-third of the genome. At the optical scale, one group of membrane proteins expresses themselves as linear structures along the cell surface boundaries, while others are sequestered; and this paper targets the former group. Segmentation of these membrane proteins on a cell-by-cell basis enables the quantitative assessment of localization for comparative analysis. However, such membrane proteins typically lack continuity, and their intensity distributions are often very heterogeneous; moreover, nuclei can form large clump, which further impedes the quantification of membrane signals on a cell-by-cell basis. To tackle these problems, we introduce a three-step process to (i) regularize the membrane signal through iterative tangential voting, (ii) constrain the location of surface proteins by nuclear features, where clumps of nuclei are segmented through a delaunay triangulation approach, and (iii) assign membrane-bound macromolecules to individual cells through an application of multi-phase geodesic level-set. We have validated our method using both synthetic data and a dataset of 200 images, and are able to demonstrate the efficacy of our approach with superior performance. PMID:25530633

  9. Studies of K-absorption on light nuclei and the search for bound nuclear kaonic states

    NASA Astrophysics Data System (ADS)

    Filippi, Alessandra; Piano, Stefano

    2011-09-01

    The available experimental data on K-absorption on nuclei are rather old and scarce: they are not enough to understand the possible formation of aggregates of nucleons bound together by a kaon, known as "Bound Kaonic Nuclear States". The existence of such structures, suggested by a few theoretical models, has not been experimentally ascertained yet. To be observed, their width should be less than their binding energy. A possible decay channel for such states is the non mesonic one, leading to hyperon-nucleon (or light nuclei) final states. Therefore, experimental investigations of possible signatures are mainly based on the analysis of hyperon-nucleon(s) correlations (for instance, of Λp(d,t) pairs) and of invariant mass spectra. Complementary information may also be gathered from missing mass distributions. Recent experiments revived, with much larger statistics, the study of K-A absorption in light nuclei: namely, KEK-E549 studied the K-interactions on 4He, while FINUDA at DAΦNE collected a large statistics on K-6,7Li, K-9Be and K-12C. The experimental results obtained so far by the various experiments studying the K-absorption in nuclei are here summarized.

  10. Dynamic Nuclear Polarization of membrane proteins: covalently bound spin-labels at protein-protein interfaces

    PubMed Central

    Wylie, Benjamin J; Dzikovski, Boris G.; Pawsey, Shane; Caporini, Marc; Rosay, Melanie; Freed, Jack H.; McDermott, Ann E.

    2016-01-01

    We demonstrate that dynamic nuclear polarization (DNP) of membrane proteins in lipid bilayers may be achieved using a novel polarizing agent: pairs of spin labels covalently bound to a protein of interest interacting at an intermolecular interaction surface. For gramicidin A, nitroxide tags attached to the N-terminal intermolecular interface region become proximal only when bimolecular channels forms in the membrane. We obtained signal enhancements of 6-fold for the dimeric protein. The enhancement affect was comparable to that of a doubly tagged sample of gramicidin C, with intramolecular spin pairs. This approach could be a powerful and selective means for signal enhancement in membrane proteins, and for recognizing intermolecular interfaces. PMID:25828256

  11. Nuclear reactor sealing system

    DOEpatents

    McEdwards, James A.

    1983-01-01

    A liquid metal-cooled nuclear reactor sealing system. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel.

  12. Bounds on the performance of a class of digital communication systems

    NASA Technical Reports Server (NTRS)

    Polk, D. R.; Gupta, S. C.; Cohn, D. L.

    1973-01-01

    Bounds on the capacity of a class of digital communication channels are derived. Equating the bounds on capacity to rate-distortion functions of (typical) sources in turn produces bounds on the performance of a class of digital communication systems. For ratios of squared quantization level to noise variance much less than one, the power requirements for this class of digital communication systems are shown to be within approximately 3 dB of the theoretical optimum.

  13. Nuclear reactor shutdown system

    DOEpatents

    Bhate, Suresh K.; Cooper, Martin H.; Riffe, Delmar R.; Kinney, Calvin L.

    1981-01-01

    An inherent shutdown system for a nuclear reactor having neutron absorbing rods affixed to an armature which is held in an upper position by a magnetic flux flowing through a Curie temperature material. The Curie temperature material is fixedly positioned about the exterior of an inner duct in an annular region through which reactor coolant flows. Elongated fuel rods extending from within the core upwardly toward the Curie temperature material are preferably disposed within the annular region. Upon abnormal conditions which result in high neutron flux and coolant temperature, the Curie material loses its magnetic permeability, breaking the magnetic flux path and allowing the armature and absorber rods to drop into the core, thus shutting down the fissioning reaction. The armature and absorber rods are retrieved by lowering the housing for the electromagnet forming coils which create a magnetic flux path which includes the inner duct wall. The coil housing then is raised, resetting the armature.

  14. Replica bounds for diluted non-Poissonian spin systems

    NASA Astrophysics Data System (ADS)

    Franz, Silvio; Leone, Michele; Lucio Toninelli, Fabio

    2003-10-01

    In this paper we extend replica bounds and free energy subadditivity arguments to diluted spin-glass models on graphs with arbitrary, non-Poissonian degree distribution. The new difficulties specific of this case are overcome introducing an interpolation procedure that stresses the relation between interpolation methods and the cavity method. As a byproduct we obtain self-averaging identities that generalize the Ghirlanda-Guerra ones to the multi-overlap case.

  15. Nuclear medicine imaging system

    DOEpatents

    Bennett, Gerald W.; Brill, A. Bertrand; Bizais, Yves J. C.; Rowe, R. Wanda; Zubal, I. George

    1986-01-01

    A nuclear medicine imaging system having two large field of view scintillation cameras mounted on a rotatable gantry and being movable diametrically toward or away from each other is disclosed. In addition, each camera may be rotated about an axis perpendicular to the diameter of the gantry. The movement of the cameras allows the system to be used for a variety of studies, including positron annihilation, and conventional single photon emission, as well as static orthogonal dual multi-pinhole tomography. In orthogonal dual multi-pinhole tomography, each camera is fitted with a seven pinhole collimator to provide seven views from slightly different perspectives. By using two cameras at an angle to each other, improved sensitivity and depth resolution is achieved. The computer system and interface acquires and stores a broad range of information in list mode, including patient physiological data, energy data over the full range detected by the cameras, and the camera position. The list mode acquisition permits the study of attenuation as a result of Compton scatter, as well as studies involving the isolation and correlation of energy with a range of physiological conditions.

  16. Nuclear medicine imaging system

    DOEpatents

    Bennett, Gerald W.; Brill, A. Bertrand; Bizais, Yves J.; Rowe, R. Wanda; Zubal, I. George

    1986-01-07

    A nuclear medicine imaging system having two large field of view scintillation cameras mounted on a rotatable gantry and being movable diametrically toward or away from each other is disclosed. In addition, each camera may be rotated about an axis perpendicular to the diameter of the gantry. The movement of the cameras allows the system to be used for a variety of studies, including positron annihilation, and conventional single photon emission, as well as static orthogonal dual multi-pinhole tomography. In orthogonal dual multi-pinhole tomography, each camera is fitted with a seven pinhole collimator to provide seven views from slightly different perspectives. By using two cameras at an angle to each other, improved sensitivity and depth resolution is achieved. The computer system and interface acquires and stores a broad range of information in list mode, including patient physiological data, energy data over the full range detected by the cameras, and the camera position. The list mode acquisition permits the study of attenuation as a result of Compton scatter, as well as studies involving the isolation and correlation of energy with a range of physiological conditions.

  17. Termination Proofs for String Rewriting Systems via Inverse Match-Bounds

    NASA Technical Reports Server (NTRS)

    Butler, Ricky (Technical Monitor); Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2004-01-01

    Annotating a letter by a number, one can record information about its history during a reduction. A string rewriting system is called match-bounded if there is a global upper bound to these numbers. In earlier papers we established match-boundedness as a strong sufficient criterion for both termination and preservation of regular languages. We show now that the string rewriting system whose inverse (left and right hand sides exchanged) is match-bounded, also have exceptional properties, but slightly different ones. Inverse match-bounded systems effectively preserve context-free languages; their sets of normalized strings and their sets of immortal strings are effectively regular. These sets of strings can be used to decide the normalization, the termination and the uniform termination problems of inverse match-bounded systems. We also show that the termination problem is decidable in linear time, and that a certain strong reachability problem is deciable, thus solving two open problems of McNaughton's.

  18. Upper and Lower Bounds to Two and Three-Electron Systems

    NASA Astrophysics Data System (ADS)

    Freund, David Eric

    Upper and lower bounds for Li('+) in non-relativistic approximation with Coulomb interaction only are calculated. We use the familiar Rayleigh-Ritz method to calculate upper bounds, and the method of intermediate problems to calculate lower bounds. Emphasis is given to the calculation of lower bounds. In particular, we have constructed our lower bounding operators using a complete set of basis functions, and we have included a positive semi-definite term that recovers some of what was lost due to truncation of the base operator. This allows us to raise the essential spectrum of the base operator for the lithium atom, which in turn paves the way for the calculation of good lower bounds for three electron atomic systems. We also present, and discuss at some length, the numerically stable algorithm we developed for the computation of two particle matrix elements.

  19. Nuclear electric propulsion systems overview

    NASA Technical Reports Server (NTRS)

    Doherty, Michael P.

    1993-01-01

    The topics are presented in viewgraph form and include the following: nuclear propulsion background; schedule for the nuclear electric propulsion (NEP) project; NEP for the Space Exploration Initiative; NEP on-going systems tasks; 20KWe mission/system study; and agenda.

  20. Nuclear weapon system risk assessment

    SciTech Connect

    Carlson, D.D.

    1993-11-01

    Probabilistic risk assessment (PRA) is a process for evaluating hazardous operations by considering what can go wrong, the likelihood of these undesired events, and the resultant consequences. Techniques used in PRA originated in the 1960s. Although there were early exploratory applications to nuclear weapons and other technologies, the first major application of these techniques was in the Reactor Safety Study, WASH-1400, {sup 1} in which the risks of nuclear power accidents were thoroughly investigated for the first time. Recently, these techniques have begun to be adapted to nuclear weapon system applications. This report discusses this application to nuclear weapon systems.

  1. The Conformation of NAD+ Bound to Lactate Dehydrogenase Determined by Nuclear Magnetic Resonance with Suppression of Spin Diffusion

    NASA Astrophysics Data System (ADS)

    Vincent, Sebastien J. F.; Zwahlen, Catherine; Post, Carol Beth; Burgner, John W.; Bodenhausen, Geoffrey

    1997-04-01

    We have reinvestigated the conformation of NAD+ bound to dogfish lactate dehydrogenase (LDH) by using an NMR experiment that allows one to exploit nuclear Overhauser effects to determine internuclear distances between pairs of protons, without perturbation of spin-diffusion effects from other protons belonging either to the cofactor or to the binding pocket of the enzyme. The analysis indicates that the structure of bound NAD+ is in accord with the conformation determined in the solid state by x-ray diffraction for the adenosine moiety, but deviates significantly from that of the nicotinamide. The NMR data indicate conformational averaging about the glycosidic bond of the nicotinamide nucleotide. In view of the strict stereospecificity of catalysis by LDH and the conformational averaging of bound NAD+ that we infer from solution-state NMR, we suggest that LDH binds the cofactor in both syn and anti conformations, but that binding interactions in the syn conformation are not catalytically productive.

  2. Global Existence for the Vlasov-Poisson System in Bounded Domains

    NASA Astrophysics Data System (ADS)

    Hwang, Hyung Ju; Velázquez, Juan J. L.

    2010-03-01

    In this paper we prove global existence for solutions of the Vlasov-Poisson system in convex bounded domains with specular boundary conditions and with a prescribed outward electrical field at the boundary.

  3. Estimation variance bounds of importance sampling simulations in digital communication systems

    NASA Technical Reports Server (NTRS)

    Lu, D.; Yao, K.

    1991-01-01

    In practical applications of importance sampling (IS) simulation, two basic problems are encountered, that of determining the estimation variance and that of evaluating the proper IS parameters needed in the simulations. The authors derive new upper and lower bounds on the estimation variance which are applicable to IS techniques. The upper bound is simple to evaluate and may be minimized by the proper selection of the IS parameter. Thus, lower and upper bounds on the improvement ratio of various IS techniques relative to the direct Monte Carlo simulation are also available. These bounds are shown to be useful and computationally simple to obtain. Based on the proposed technique, one can readily find practical suboptimum IS parameters. Numerical results indicate that these bounding techniques are useful for IS simulations of linear and nonlinear communication systems with intersymbol interference in which bit error rate and IS estimation variances cannot be obtained readily using prior techniques.

  4. Lipopolysaccharide-bound structure of the antimicrobial peptide cecropin P1 determined by nuclear magnetic resonance spectroscopy.

    PubMed

    Baek, Mi-Hwa; Kamiya, Masakatsu; Kushibiki, Takahiro; Nakazumi, Taichi; Tomisawa, Satoshi; Abe, Chiharu; Kumaki, Yasuhiro; Kikukawa, Takashi; Demura, Makoto; Kawano, Keiichi; Aizawa, Tomoyasu

    2016-04-01

    Antimicrobial peptides (AMPs) are components of the innate immune system and may be potential alternatives to conventional antibiotics because they exhibit broad-spectrum antimicrobial activity. The AMP cecropin P1 (CP1), isolated from nematodes found in the stomachs of pigs, is known to exhibit antimicrobial activity against Gram-negative bacteria. In this study, we investigated the interaction between CP1 and lipopolysaccharide (LPS), which is the main component of the outer membrane of Gram-negative bacteria, using circular dichroism (CD) and nuclear magnetic resonance (NMR). CD results showed that CP1 formed an α-helical structure in a solution containing LPS. For NMR experiments, we expressed (15) N-labeled and (13) C-labeled CP1 in bacterial cells and successfully assigned almost all backbone and side-chain proton resonance peaks of CP1 in water for transferred nuclear Overhauser effect (Tr-NOE) experiments in LPS. We performed (15) N-edited and (13) C-edited Tr-NOE spectroscopy for CP1 bound to LPS. Tr-NOE peaks were observed at the only C-terminal region of CP1 in LPS. The results of structure calculation indicated that the C-terminal region (Lys15-Gly29) formed the well-defined α-helical structure in LPS. Finally, the docking study revealed that Lys15/Lys16 interacted with phosphate at glucosamine I via an electrostatic interaction and that Ile22/Ile26 was in close proximity with the acyl chain of lipid A. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:26939541

  5. Feedback-bounded stabilisation of certain discrete Volterra systems

    NASA Astrophysics Data System (ADS)

    Kotsios, Stelios

    2016-06-01

    Throughout this paper, we present a method for designing feedback-laws which stabilise nonlinear discrete Volterra systems. Our method is based on a factorisation algorithm which decomposes the original system as a composition of a δ-polynomial and a linear series.

  6. Control of Future Air Traffic Systems via Complexity Bound Management

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia

    2013-01-01

    The complexity of the present system for managing air traffic has led to "discreteness" in approaches to creating new concepts: new concepts are created as point designs, based on experience, expertise, and creativity of the proposer. Discrete point designs may be highly successful but they are difficult to substantiate in the face of equally strong substantiation of competing concepts, as well as the state of the art in concept evaluation via simulations. Hybrid concepts may present a compromise - the golden middle. Yet a hybrid of sometimes in principle incompatible concepts forms another point design that faces the challenge of substantiation and validation. We are faced with the need to re-design the air transportation system ab initio. This is a daunting task, especially considering the problem of transitioning from the present system to any fundamentally new system. However, design from scratch is also an opportunity to reconsider approaches to new concept development. In this position paper we propose an approach, Optimized Parametric Functional Design, for systematic development of concepts for management and control of airspace systems, based on optimization formulations in terms of required system functions and states. This reasoning framework, realizable in the context of ab initio system design, offers an approach to deriving substantiated airspace management and control concepts. With growing computational power, we hope that the approach will also yield a methodology for actual dynamic control of airspace

  7. Robust levitation control for maglev systems with guaranteed bounded airgap.

    PubMed

    Xu, Jinquan; Chen, Ye-Hwa; Guo, Hong

    2015-11-01

    The robust control design problem for the levitation control of a nonlinear uncertain maglev system is considered. The uncertainty is (possibly) fast time-varying. The system has magnitude limitation on the airgap between the suspended chassis and the guideway in order to prevent undesirable contact. Furthermore, the (global) matching condition is not satisfied. After a three-step state transformation, a robust control scheme for the maglev vehicle is proposed, which is able to guarantee the uniform boundedness and uniform ultimate boundedness of the system, regardless of the uncertainty. The magnitude limitation of the airgap is guaranteed, regardless of the uncertainty. PMID:26524957

  8. Study of Double-strangeness Nuclear Systems with Nuclear Emulsion

    NASA Astrophysics Data System (ADS)

    Nakazawa, Kazuma; Endo, Yoko; Hoshino, Kaoru; Ito, Hiroki; Kinbara, Shinji; Kobayashi, Hidetaka; Mishina, Akihiro; Soe, Myint Kyaw; Theint, Aye Moh Moh; Xu, Rong; Tint, Khin Than; Yoshida, Jun'ya; Zhang, Dong Hai

    Double strangeness nuclei such as double-Λ and Ξ hypernuclei have been studied with nuclear emulsion due to its fine position resolution. Recently, we have started an experiment to study Λ-Λ interaction more accurately than that information given by the NAGARA event with ∼102 double-Λ hypernuclei which may provide us understanding free from nuclear medium effect. It is necessary to develop treatment method for huge amount, 2.1 tons of the emulsion gel, even if very pure K- beams are available at J-PARC. We have developed the base film to support the emulsion, emulsion surface coating method with a special layer of 0.5 μm thick, method for making large-size plate (35.0 x 34.5 cm2) and scanning method, called "overall scanning". The first evidence of a deeply bound state of Ξ--14N system, named KISO, was successfully detected in the test operation of the overall scanning.

  9. Homeward Bound: Ecological Design of Domestic Information Systems

    NASA Astrophysics Data System (ADS)

    Wastell, David G.; Sauer, Juergen S.; Schmeink, Claudia

    Information technology artefacts are steadily permeating everyday life, just as they have colonized the business domain. Although research in our field has largely addressed the workplace, researchers are beginning to take an interest in the home environment too. Here, we address the domestic realm, focusing on the design of complex, interactive information systems. As such, our work sits in the design science version rather than behavioral science paradigm of IS research. We argue that the home is in many ways a more challenging environment for the designer than the workplace, making good design of critical importance. Regrettably, the opposite would appear to be the norm. Two experiments are reported, both concerned with the design of the user interface for domestic heating systems. Of note is our use of a medium-fidelity laboratory simulation or "microworld" in this work. Two main substantive findings resulted. First, that ecologically designed feedback, embodying a strong mapping between task goals and system status, produced superior task performance. Second, that predictive decision aids provided clear benefits over other forms of user support, such as advisory systems. General implications for the design of domestic information systems are discussed, followed by reflections on the nature of design work in IS, and on the design science project itself. It is concluded that the microworld approach has considerable potential for developing IS design theory. The methodological challenges of design research are highlighted, especially the presence of additional validity threats posed by the need to construct artefacts in order to evaluate theory. It is argued that design theory is necessarily complex, modal, and uncertain, and that design science (like design itself) should be prosecuted in an open, heuristic spirit, drawing more on the proven methods of "good design" (e.g.,prototyping, user participation) in terms of its own praxis.

  10. Spin–orbit coupling rule in bound fermion systems

    NASA Astrophysics Data System (ADS)

    Ebran, J.-P.; Khan, E.; Mutschler, A.; Vretenar, D.

    2016-08-01

    Spin–orbit coupling characterizes quantum systems such as atoms, nuclei, hypernuclei, quarkonia, etc, and is essential for understanding their spectroscopic properties. Depending on the system, the effect of spin–orbit coupling on shell structure is large in nuclei, small in quarkonia and perturbative in atoms. In the standard non-relativistic reduction of the single-particle Dirac equation, we derive a universal rule for the relative magnitude of the spin–orbit effect that applies to very different quantum systems, regardless of whether the spin–orbit coupling originates from the strong or electromagnetic interaction. It is shown that in nuclei the near equality of the mass of the nucleon and the difference between the large repulsive and attractive potentials explain the fact that spin–orbit splittings are comparable to the energy spacing between major shells. For a specific ratio between the particle mass and the effective potential whose gradient determines the spin–orbit force, we predict the occurrence of giant spin–orbit energy splittings that dominate the single-particle excitation spectrum.

  11. NUCLEAR REACTOR CONTROL SYSTEM

    DOEpatents

    Howard, D.F.; Motta, E.E.

    1961-06-27

    A method for controlling the excess reactivity in a nuclear reactor throughout the core life while maintaining the neutron flux distribution at the desired level is described. The control unit embodies a container having two electrodes of different surface area immersed in an electrolytic solution of a good neutron sbsorbing metal ion such as boron, gadolinium, or cadmium. Initially, the neutron absorber is plated on the larger electrode to control the greater neutron flux of a freshly refueled core. As the fuel burns up, the excess reactivity decreases and the neutron absorber is then plated onto the smaller electrode so that the number of neutrons absorbed also decreases. The excess reactivity in the core may thus be maintained without the introduction of serious perturbations in the neutron flux distributibn.

  12. Biological systems drug infusion controller using FREN with sliding bounds.

    PubMed

    Chidentree, Treesatayapun; Sermsak, Uatrongjit

    2006-11-01

    In this paper, a direct adaptive control for drug infusion of biological systems is presented. The proposed controller is accomplished using our adaptive network called Fuzzy Rules Emulated Network (FREN). The structure of FREN resembles the human knowledge in the form of fuzzy IF-THEN rules. After selecting the initial value of network's parameters, an on-line adaptive process based on Lyapunov's criteria is performed to improve the controller performance. The control signal from FREN is designed to keep in the region which is calculated by the modified Sliding Mode Control (SMC). The simulation results indicate that the proposed algorithm can satisfy the setting point and the robust performance. PMID:17073348

  13. Optimal feedback control of strongly non-linear systems excited by bounded noise

    NASA Astrophysics Data System (ADS)

    Zhu, W. Q.; Huang, Z. L.; Ko, J. M.; Ni, Y. Q.

    2004-07-01

    A strategy for non-linear stochastic optimal control of strongly non-linear systems subject to external and/or parametric excitations of bounded noise is proposed. A stochastic averaging procedure for strongly non-linear systems under external and/or parametric excitations of bounded noise is first developed. Then, the dynamical programming equation for non-linear stochastic optimal control of the system is derived from the averaged Itô equations by using the stochastic dynamical programming principle and solved to yield the optimal control law. The Fokker-Planck-Kolmogorov equation associated with the fully completed averaged Itô equations is solved to give the response of optimally controlled system. The application and effectiveness of the proposed control strategy are illustrated with the control of cable vibration in cable-stayed bridges and the feedback stabilization of the cable under parametric excitation of bounded noise.

  14. D*Ξ N bound state in strange three-body systems

    NASA Astrophysics Data System (ADS)

    Garcilazo, H.; Valcarce, A.

    2016-06-01

    The recent update of the strangeness -2 ESC08c Nijmegen potential incorporating the NAGARA and KISO events predicts a Ξ N bound state, D*, in the S31(I =1 ) channel. We study if the existence of this two-body bound state could give rise to stable three-body systems. For this purpose we solve the bound state problem of three-body systems where the Ξ N state is merged with N 's , Λ 's , Σ 's , or Ξ 's , making use of the most recent updates of the two-body ESC08c Nijmegen potentials. We found that there appear stable states in the Ξ N N and Ξ Ξ N systems, the Ξ Λ N and Ξ Σ N systems being unbound.

  15. Materials challenges for nuclear systems

    SciTech Connect

    Allen, Todd; Busby, Jeremy; Meyer, Mitch; Petti, David

    2010-11-26

    The safe and economical operation of any nuclear power system relies to a great extent, on the success of the fuel and the materials of construction. During the lifetime of a nuclear power system which currently can be as long as 60 years, the materials are subject to high temperature, a corrosive environment, and damage from high-energy particles released during fission. The fuel which provides the power for the reactor has a much shorter life but is subject to the same types of harsh environments. This article reviews the environments in which fuels and materials from current and proposed nuclear systems operate and then describes how the creation of the Advanced Test Reactor National Scientific User Facility is allowing researchers from across the U.S. to test their ideas for improved fuels and materials.

  16. Space Weather Prediction Error Bounding for Real-Time Ionospheric Threat Adaptation of GNSS Augmentation Systems

    NASA Astrophysics Data System (ADS)

    Lee, J.; Yoon, M.; Lee, J.

    2014-12-01

    Current Global Navigation Satellite Systems (GNSS) augmentation systems attempt to consider all possible ionospheric events in their correction computations of worst-case errors. This conservatism can be mitigated by subdividing anomalous conditions and using different values of ionospheric threat-model bounds for each class. A new concept of 'real-time ionospheric threat adaptation' that adjusts the threat model in real time instead of always using the same 'worst-case' model was introduced in my previous research. The concept utilizes predicted values of space weather indices for determining the corresponding threat model based on the pre-defined worst-case threat as a function of space weather indices. Since space weather prediction is not reliable due to prediction errors, prediction errors are needed to be bounded to the required level of integrity of the system being supported. The previous research performed prediction error bounding using disturbance, storm time (Dst) index. The distribution of Dst prediction error over the 15-year data was bounded by applying 'inflated-probability density function (pdf) Gaussian bounding'. Since the error distribution has thick and non-Gaussian tails, investigation on statistical distributions which properly describe heavy tails with less conservatism is required for the system performance. This paper suggests two potential approaches for improving space weather prediction error bounding. First, we suggest using different statistical models when fit the error distribution, such as the Laplacian distribution which has fat tails, and the folded Gaussian cumulative distribution function (cdf) distribution. Second approach is to bound the error distribution by segregating data based on the overall level of solar activity. Bounding errors using only solar minimum period data will have less uncertainty and it may allow the use of 'solar cycle prediction' provided by NASA when implementing to real-time threat adaptation. Lastly

  17. Lower bounds for sums of eigenvalues of elliptic operators and systems

    SciTech Connect

    Ilyin, Aleksei A

    2013-04-30

    Two-term lower bounds of Berzin-Li-Yau type are obtained for the sums of eigenvalues of elliptic operators and systems with constant coefficients and Dirichlet boundary conditions. The polyharmonic operator, the Stokes system and its generalizations, the two-dimensional buckling problem, and also the Klein-Gordon operator are considered. Bibliography: 32 titles.

  18. Adiabatic hyperspherical study of weakly bound helium-helium-alkali-metal triatomic systems

    SciTech Connect

    Suno, Hiroya; Esry, B. D.

    2010-12-15

    {sup 4}He{sub 2}-alkali-metal triatomic molecular systems are studied using the adiabatic hyperspherical representation. By adopting the best pairwise He-He and He-X interaction potentials, we search for weakly bound states of {sup 4}He{sub 2}X systems with X={sup 6}Li, {sup 7}Li, {sup 23}Na, {sup 39}K, {sup 40}K, {sup 41}K, {sup 85}Rb, {sup 87}Rb, and {sup 133}Cs. We consider not only zero total angular momentum J=0 states, but also J>0 states. We find that the {sup 4}He{sub 2}{sup 6}Li and {sup 4}He{sub 2}{sup 7}Li systems each possess two bound states with J{sup {Pi}=}0{sup +} symmetry and none with J>0, while the other {sup 4}He{sub 2}-alkali-metal species are found to support one 0{sup +} and one 1{sup -} bound state. We calculate the bound-state energies of these molecular species and discuss the essential features of the wave functions associated with these bound states.

  19. A Search for deeply-bound Kaonic nuclear state at the J-PARC E15 experiment

    SciTech Connect

    Sada, Y.

    2011-10-21

    The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K-barNN, by the in-flight {sup 3}He(K{sup -},N) reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron or proton, and the invariant mass via the expected decay, e.g. K{sup -}pp{yields}{Lambda}p{yields}p{pi}{sup -}p. an overview of the experiment and the preparation status are reported.

  20. A search for deeply-bound kaonic nuclear state at the J-PARC E15 experiment

    NASA Astrophysics Data System (ADS)

    Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Poli Lener, M.; Romero Vidal, A.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2013-09-01

    The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, KbarNN, by the in-flight He3(K-,N) reaction. The exclusive measurement will be performed by a simultaneous measurement of the missing mass using the forward neutron or proton, and the invariant mass via the expected decay, e.g. K-pp→Λp→pπ-p. In this report, an overview of the experiment and an analysis of engineering runs performed in February and June are presented.

  1. Dynamic Analysis of Nuclear Energy System Strategies

    SciTech Connect

    Den Durpel, Luc Van

    2004-06-17

    DANESS is an integrated process model for nuclear energy systems allowing the simulation of multiple reactors and fuel cycles in a continuously changing nuclear reactor park configuration. The model is energy demand driven and simulates all nuclear fuel cycle facilites, up to 10 reactors and fuels. Reactor and fuel cycle facility history are traced and the cost of generating energy is calculated per reactor and for total nuclear energy system. The DANESS model aims at performing dynamic systems analysis of nuclear energy development used for integrated analysis of development paths for nuclear energy, parameter scoping for new nuclear energy systems, economic analysis of nuclear energy, government role analysis, and education.

  2. Improved rigorous upper bounds for transport due to passive advection described by simple models of bounded systems

    SciTech Connect

    Kim, Chang-Bae; Krommes, J.A.

    1988-08-01

    The work of Krommes and Smith on rigorous upper bounds for the turbulent transport of a passively advected scalar (/ital Ann. Phys./ 177:246 (1987)) is extended in two directions: (1) For their ''reference model,'' improved upper bounds are obtained by utilizing more sophisticated two-time constraints which include the effects of cross-correlations up to fourth order. Numerical solutions of the model stochastic differential equation are also obtained; they show that the new bounds compare quite favorably with the exact results, even at large Reynolds and Kubo numbers. (2) The theory is extended to take account of a finite spatial autocorrelation length L/sub c/. As a reasonably generic example, the problem of particle transport due to statistically specified stochastic magnetic fields in a collisionless turbulent plasma is revisited. A bound is obtained which reduces for small L/sub c/ to the quasilinear limit and for large L/sub c/ to the strong turbulence limit, and which provides a reasonable and rigorous interpolation for intermediate values of L/sub c/. 18 refs., 6 figs.

  3. A search for deeply bound kaonic nuclear states at J-PARC

    NASA Astrophysics Data System (ADS)

    Hiraiwa, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadirenn, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Fukuda, Y.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Iio, M.; Iliescu, M.; Inoue, K.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreau, D.; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Sekimoto, M.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    2010-08-01

    J-PARC E15 experiment aims to search for the lightest kaonic nuclei, namely K-pp bound states, using in-flight (K-, n) reactions. The advantage of this experiment is to perform exclusive measurement by missing mass study using the primary neutrons and invariant mass spectroscopy via such decay as K-pp→Λp→pπ-p, simultaneously. In this report, an overview of this experiment and the current status are presented.

  4. Space-Bounded Church-Turing Thesis and Computational Tractability of Closed Systems

    NASA Astrophysics Data System (ADS)

    Braverman, Mark; Schneider, Jonathan; Rojas, Cristóbal

    2015-08-01

    We report a new limitation on the ability of physical systems to perform computation—one that is based on generalizing the notion of memory, or storage space, available to the system to perform the computation. Roughly, we define memory as the maximal amount of information that the evolving system can carry from one instant to the next. We show that memory is a limiting factor in computation even in lieu of any time limitations on the evolving system—such as when considering its equilibrium regime. We call this limitation the space-bounded Church-Turing thesis (SBCT). The SBCT is supported by a simulation assertion (SA), which states that predicting the long-term behavior of bounded-memory systems is computationally tractable. In particular, one corollary of SA is an explicit bound on the computational hardness of the long-term behavior of a discrete-time finite-dimensional dynamical system that is affected by noise. We prove such a bound explicitly.

  5. Probable systemic lupus erythematosus with cell-bound complement activation products (CB-CAPS).

    PubMed

    Lamichhane, D; Weinstein, A

    2016-08-01

    Complement activation is a key feature of systemic lupus erythematosus (SLE). Detection of cell-bound complement activation products (CB-CAPS) occurs more frequently than serum hypocomplementemia in definite lupus. We describe a patient with normocomplementemic probable SLE who did not fulfill ACR classification criteria for lupus, but the diagnosis was supported by the presence of CB-CAPS. PMID:26911153

  6. Symbol error rate bound of DPSK modulation system in directional wave propagation

    NASA Astrophysics Data System (ADS)

    Hua, Jingyu; Zhuang, Changfei; Zhao, Xiaomin; Li, Gang; Meng, Qingmin

    This paper presents a new approach to determine the symbol error rate (SER) bound of differential phase shift keying (DPSK) systems in a directional fading channel, where the von Mises distribution is used to illustrate the non-isotropic angle of arrival (AOA). Our approach relies on the closed-form expression of the phase difference probability density function (pdf) in coherent fading channels and leads to expressions of the DPSK SER bound involving a single finite-range integral which can be readily evaluated numerically. Moreover, the simulation yields results consistent with numerical computation.

  7. Radioprotection of Human Cell Nuclear DNA by Polyamines: Radiosensitivity of Chromatin is Influenced by Tightly Bound Spermine

    NASA Technical Reports Server (NTRS)

    Warters, Raymond L.; Newton, Gerald L.; Olive, Peggy L.; Fahey, Robert C.

    1999-01-01

    The polyamines putrescine (PUT) and spermine (SPM) were examined for their ability to protect human cell Deoxyribonucleic Acid (DNA) against the formation of radiation-induced double-strand breaks (DSBs). As observed previously, under conditions where polyamines were shown to be almost completely absent, association with nuclear matrix protein into a nucleoid, and organization into chromatin structure, protected DNA from induction of DSBs by factors of 4.5 and 95, respectively. At concentrations below 1 mM, PUT or SPM provided equivalent levels of protection to deproteinized nuclear DNA, consistent with their capacity to scavenge radiation-induced radicals. At constant ionic strength, 5 mM SPM protected deproteinized DNA and nucleoid DNA and DNA in nuclear chromatin by factors of 100 and 26, respectively. At 5 mM, SPM provided 15 times greater protection of deproteinized DNA than did PUT. Under physiologically relevant conditions, 5 mM SPM protected DNA in the intact nucleus from the induction of DSBs by a factor of 2 relative to DNA in the absence of SPM. Studies of SPM binding during cellular fractionation revealed that a significant fraction of the cellular SPM is tightly bound in the nucleus but can be removed by extended washing. Thus the association of SPM with nuclear chromatin appears to be a significant contributor to the resistance of the cell's DNA to the induction of DSBs.

  8. Bounding the Failure Probability Range of Polynomial Systems Subject to P-box Uncertainties

    NASA Technical Reports Server (NTRS)

    Crespo, Luis G.; Kenny, Sean P.; Giesy, Daniel P.

    2012-01-01

    This paper proposes a reliability analysis framework for systems subject to multiple design requirements that depend polynomially on the uncertainty. Uncertainty is prescribed by probability boxes, also known as p-boxes, whose distribution functions have free or fixed functional forms. An approach based on the Bernstein expansion of polynomials and optimization is proposed. In particular, we search for the elements of a multi-dimensional p-box that minimize (i.e., the best-case) and maximize (i.e., the worst-case) the probability of inner and outer bounding sets of the failure domain. This technique yields intervals that bound the range of failure probabilities. The offset between this bounding interval and the actual failure probability range can be made arbitrarily tight with additional computational effort.

  9. Materials challenges for nuclear systems

    DOE PAGESBeta

    Allen, Todd; Busby, Jeremy; Meyer, Mitch; Petti, David

    2010-11-26

    The safe and economical operation of any nuclear power system relies to a great extent, on the success of the fuel and the materials of construction. During the lifetime of a nuclear power system which currently can be as long as 60 years, the materials are subject to high temperature, a corrosive environment, and damage from high-energy particles released during fission. The fuel which provides the power for the reactor has a much shorter life but is subject to the same types of harsh environments. This article reviews the environments in which fuels and materials from current and proposed nuclearmore » systems operate and then describes how the creation of the Advanced Test Reactor National Scientific User Facility is allowing researchers from across the U.S. to test their ideas for improved fuels and materials.« less

  10. Consideration of critically when directly disposing highly enriched spent nuclear fuel in unsaturated tuff: Bounding estimates

    SciTech Connect

    Rechard, R.P.; Tierney, M.S.; Sanchez, L.C.; Martell, M.-A.

    1996-05-01

    This report presents one of 2 approaches (bounding calculations) which were used in a 1994 study to examine the possibility of a criticality in a repository. Bounding probabilities, although rough, point to the difficulty of creating conditions under which a critical mass could be assembled (container corrosion, separation of neutron absorbers from fissile material, collapse or precipitation of fissile material) and how significant the geochemical and hydrologic phenomena are. The study could not conceive of a mechanism consistent with conditions under which an atomic explosion could occur. Should a criticality occur in or near a container in the future, boundary consequence calculations showed that fissions from one critical event (<10{sup 20} fissions, if similar to aqueous and metal accidents and experiments) are quite small compared to the amount of fissions represented by the spent fuel itself. If it is assumed that the containers necessary to hold the highly enriched spent fuel went critical once per day for 1 million years, creating an energy release of about 10{sup 20} fissions, the number of fissions equals about 10{sup 28}, which corresponds to only 1% of the fission inventory in a repository containing 70,000 metric tons of heavy metal, the expected size for the proposed repository at Yucca Mountain, Nevada.

  11. Capturing asteroids into bound orbits around the earth: Massive early return on an asteroid terminal defense system

    SciTech Connect

    Hills, J.G.

    1992-02-06

    Nuclear explosives may be used to capture small asteroids (e.g., 20--50 meters in diameter) into bound orbits around the earth. The captured objects could be used for construction material for manned and unmanned activity in Earth orbit. Asteroids with small approach velocities, which are the ones most likely to have close approaches to the Earth, require the least energy for capture. They are particularly easy to capture if they pass within one Earth radius of the surface of the Earth. They could be intercepted with intercontinental missiles if the latter were retrofit with a more flexible guiding and homing capability. This asteroid capture-defense system could be implemented in a few years at low cost by using decommissioned ICMs. The economic value of even one captured asteroid is many times the initial investment. The asteroid capture system would be an essential part of the learning curve for dealing with larger asteroids that can hit the earth.

  12. Molecular Andreev bound states and Majorana modes in a double dot system

    NASA Astrophysics Data System (ADS)

    Vernek, Edson; Silva, Joelson F.

    Nanostructured systems such as quantum dots (QD) connected to superconductors has attracted a lot of attention in the recent years. One of the well known phenomena in such a system is the formation of a pair of bound called Andreev bound states (ABS). Recently, it have been shown that when a QD is coupled to a topological superconductor wire, a Majorana bound state (MBS) leaks from the end of the wire into the dot. The character of these bound states is much reacher in structures like molecules and is far from being completely understood. In this work we study a system composed by a two inter-connected QDs in which one of then is coupled to a normal superconductor and to a normal lead while the other is coupled to a topological superconductor and to a distinct normal metallic lead. We show that in the atomic limit (for small interdot coupling), one of the dot has a pair of ABS whereas the other has a single a MBS. More interestingly, in the molecular regime (large inter-dot coupling) we observe a localized Majorana mode coexisting with a delocalized molecular ABS. We would like to thank financial support from the Brazilian agencies CNPq, CAPES and FAPEMIG.

  13. Upgraded NERVA systems: Enabler nuclear system

    NASA Technical Reports Server (NTRS)

    Farbman, Gerry

    1991-01-01

    The NERVA/Rover Enabler technology enables to go on a low risk, short-term program to meet the requirements of the Mars mission and maybe some lunar missions. The following subject areas are covered: NERVA technology - the foundation for tomorrow's space missions; NERVA/Rover reactor system test sequence; NERVA engine development program; nuclear thermal reactor capability based on many related Westinghouse technology programs; investment in Rover/Nerva technology; synergistic applications of NERVA technology; flow schematic of the NDR engine; the NERVA nuclear subsystem; and technology evolution.

  14. Bounds for a new chaotic system and its application in chaos synchronization

    NASA Astrophysics Data System (ADS)

    Zhang, Fuchen; Shu, Yonglu; Yang, Hongliang

    2011-03-01

    This paper has investigated the localization problem of compact invariant sets of a new chaotic system with the help of the iteration theorem and the first order extremum theorem. If there are more iterations, then the estimation for the bound of the system will be more accurate, because the shape of the chaotic attractor is irregular. We establish that all compact invariant sets of this system are located in the intersection of a ball with two frusta and we also compute its parameters. It is a great advantage that we can attain a smaller bound of the chaotic attractor compared with the classical method. One numerical example illustrating a localization of a chaotic attractor is presented as well.

  15. The Search for Deeply Bound Kaonic Nuclear States at J-Parc

    NASA Astrophysics Data System (ADS)

    Hiraiwa, T.; Ajimura, S.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Iio, M.; Iliescu, M.; Inoue, K.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kienle, P.; Kou, H.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Pietreanu, D.; Lener, M. Poli; Vidal, A. Romero; Sada, Y.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Doce, O. Vazquez; Widmann, E.; Yamazaki, T.; Yim, H.; Zmeskal, J.

    The J-PARC E15 experiment aims to search for the lightest kaonic nuclear states, namely K-pp, using in-flight (K-, n) reaction on 3He. In this experiment, the missing mass in the (K-, n) reaction and the invariant mass of the decay such as K-pp → Λp → pπ-p will be measured simultaneously. In this article, the experimental feature and the present status are presented.

  16. Nuclear criticality safety bounding analysis for the in-tank-precipitation (ITP) process, impacted by fissile isotopic weight fractions

    SciTech Connect

    Bess, C.E.

    1994-04-22

    The In-Tank Precipitation process (ITP) receives High Level Waste (HLW) supernatant liquid containing radionuclides in waste processing tank 48H. Sodium tetraphenylborate, NaTPB, and monosodium titanate (MST), NaTi{sub 2}O{sub 5}H, are added for removal of radioactive Cs and Sr, respectively. In addition to removal of radio-strontium, MST will also remove plutonium and uranium. The majority of the feed solutions to ITP will come from the dissolution of supernate that had been concentrated by evaporation to a crystallized salt form, commonly referred to as saltcake. The concern for criticality safety arises from the adsorption of U and Pt onto MST. If sufficient mass and optimum conditions are achieved then criticality is credible. The concentration of u and Pt from solution into the smaller volume of precipitate represents a concern for criticality. This report supplements WSRC-TR-93-171, Nuclear Criticality Safety Bounding Analysis For The In-Tank-Precipitation (ITP) Process. Criticality safety in ITP can be analyzed by two bounding conditions: (1) the minimum safe ratio of MST to fissionable material and (2) the maximum fissionable material adsorption capacity of the MST. Calculations have provided the first bounding condition and experimental analysis has established the second. This report combines these conditions with canyon facility data to evaluate the potential for criticality in the ITP process due to the adsorption of the fissionable material from solution. In addition, this report analyzes the potential impact of increased U loading onto MST. Results of this analysis demonstrate a greater safety margin for ITP operations than the previous analysis. This report further demonstrates that the potential for criticality in the ITP process due to adsorption of fissionable material by MST is not credible.

  17. Equation of state of dense nuclear matter and an upper bound on neutron star masses

    NASA Astrophysics Data System (ADS)

    Negi, P. S.; Durgapal, M. C.

    2001-02-01

    We have discussed, in general, the important physical parameters, like maximum mass, radius, and the minimum rotation period of self-bound, causally consistent, and pulsationally stable neutron stars (Q-star models) by using a realistic stiff EOS (such that, the speed of sound, v~ P, or nP=K(E-E), where K<= 1 and n =1/(1-2N) where P and E represent respectively, the pressure and the energy-density, and E is the value of E at the surface (r = a) of the configuration) within the two constraints imposed by: (i) The minimum rotation period, P, for the pulsar known to date corresponds to 1.558 ms, and (ii) The maximum number density anywhere inside the structure for the models described as Q-stars cannot exceed ~ 1 nucleon/fm^3. By using the empirical formula given by Koranda, Stergioulas and Friedman (1997) (KSF-formula), and imposing constraint (i), we have obtained an upper bound of M ≅ 7.76 M radius a≅ 32.5 km, and the central energy-density around 2.17 × 10^14 g cm^-3 (for n =1.01). Constraint (ii) provides the minimum rotation period, P ~ 0.489 ms for the maximum mass M ~ 2.4 M_solar, and the central energy-density around 2.20 × 10^15 g cm^-3 (for n =1.01). The speed of sound at the centre of these models approaches ~ 99% of the speed of light `c' (in the vacuum) and vanishes at the surface of the configuration together with pressure. If we relax the maximum Kepler frequency imposed by the fastest rotating pulsar known to date (constraint (i)), in view of certain observational effects and theoretical evidences, and allow the present EOS to produce larger rotation rates than the 1.558 ms pulsar, the maximum mass of the non-rotating model drops down to a value ~ 7.2 M_solar. The higher values of masses (>= 7 M_solar) and radii (~ 31-32 km) obtained in this study imply that these models may represent the massive compact objects like Cyg X-1, Cyg XR-1, LMC X-3, and others which are known as black hole candidates (BHCs). This study also suggest that the strongest

  18. NCIS - a Nuclear Criticality Information System (overview)

    SciTech Connect

    Koponen, B.L.; Hampel, V.E.

    1983-07-01

    A Nuclear Criticality Information System (NCIS) is being established at the Lawrence Livermore National Laboratory (LLNL) in order to serve personnel responsible for safe storage, transport, and handling of fissile materials and those concerned with the evaluation and analysis of nuclear, critical experiments. Public concern for nuclear safety provides the incentive for improved access to nuclear safety information.

  19. Emergence of scale-free characteristics in socio-ecological systems with bounded rationality

    PubMed Central

    Kasthurirathna, Dharshana; Piraveenan, Mahendra

    2015-01-01

    Socio–ecological systems are increasingly modelled by games played on complex networks. While the concept of Nash equilibrium assumes perfect rationality, in reality players display heterogeneous bounded rationality. Here we present a topological model of bounded rationality in socio-ecological systems, using the rationality parameter of the Quantal Response Equilibrium. We argue that system rationality could be measured by the average Kullback–-Leibler divergence between Nash and Quantal Response Equilibria, and that the convergence towards Nash equilibria on average corresponds to increased system rationality. Using this model, we show that when a randomly connected socio-ecological system is topologically optimised to converge towards Nash equilibria, scale-free and small world features emerge. Therefore, optimising system rationality is an evolutionary reason for the emergence of scale-free and small-world features in socio-ecological systems. Further, we show that in games where multiple equilibria are possible, the correlation between the scale-freeness of the system and the fraction of links with multiple equilibria goes through a rapid transition when the average system rationality increases. Our results explain the influence of the topological structure of socio–ecological systems in shaping their collective cognitive behaviour, and provide an explanation for the prevalence of scale-free and small-world characteristics in such systems. PMID:26065713

  20. Quantum transport through the system of parallel quantum dots with Majorana bound states

    SciTech Connect

    Wang, Ning; Li, Yuxian; Lv, Shuhui

    2014-02-28

    We study the tunneling transport properties through a system of parallel quantum dots which are coupled to Majorana bound states (MBSs). The conductance and spectral function are computed using the retarded Green's function method based on the equation of motion. The conductance of the system is 2e{sup 2}/h at zero Fermi energy and is robust against the coupling between the MBSs and the quantum dots. The dependence of the Fermi energy on the spectral function is different for the first dot (dot1) than for the second dot (dot2) with fixed dot2-MBSs coupling. The influence of the Majorana bound states on the spectral function was studied for the series and parallel configurations of the system. It was found that when the configuration is in series, the Majorana bound states play an important role, resulting in a spectral function with three peaks. However, the spectral function shows two peaks when the system is in a parallel configuration. The zero Fermi energy spectral function is always 1/2 not only in series but also in the parallel configuration and robust against the coupling between the MBSs and the quantum dots. The phase diagram of the Fermi energy versus the quantum dot energy levels was also investigated.

  1. A methodology for computing uncertainty bounds of multivariable systems based on sector stability theory concepts

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R.

    1992-01-01

    The application of a sector-based stability theory approach to the formulation of useful uncertainty descriptions for linear, time-invariant, multivariable systems is explored. A review of basic sector properties and sector-based approach are presented first. The sector-based approach is then applied to several general forms of parameter uncertainty to investigate its advantages and limitations. The results indicate that the sector uncertainty bound can be used effectively to evaluate the impact of parameter uncertainties on the frequency response of the design model. Inherent conservatism is a potential limitation of the sector-based approach, especially for highly dependent uncertain parameters. In addition, the representation of the system dynamics can affect the amount of conservatism reflected in the sector bound. Careful application of the model can help to reduce this conservatism, however, and the solution approach has some degrees of freedom that may be further exploited to reduce the conservatism.

  2. Finding the exact delay bound for consensus of linear multi-agent systems

    NASA Astrophysics Data System (ADS)

    Cepeda-Gomez, Rudy

    2016-08-01

    This paper focuses on consensus problems for high-order, linear multi-agent systems. Undirected communication topologies along with a fixed and uniform communication time delay are taken into account. This class of problems has been widely studied in the literature, but there are still gaps concerning the exact stability bounds in the domain of the delays. The novelty of this paper lies in the determination of an exact and explicit delay bound for consensus. This is done in a very efficient manner by using the cluster treatment of characteristic roots (CTCR) paradigm. Before the stability analysis, a state transformation is performed to decouple the system and simplify the problem. CTCR is then deployed to the individual subsystems to obtain the stability margin in the domain of the delays without the conservatism introduced by other approaches more frequently found in the literature. Simulation results are presented to support the analytical claims.

  3. Recent Advances in Nuclear Reaction Theories for Weakly Bound Nuclei: Reexamining the Problem of Inclusive Breakup

    NASA Astrophysics Data System (ADS)

    Moro, Antonio M.; Lei, Jin

    2016-05-01

    The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the theory proposed by Ichimura et al. (Phys Rev C 32:431, 1985) is revisited, both in its prior and post representations. We briefly outline the connection of this theory with that proposed by Udagawa and Tamura (Phys Rev C 24:1348, 1981) and apply both theories to the inclusive breakup of ^6Li on ^{209}Bi at near-barrier energies, comparing also with available data. The relative importance of elastic versus non-elastic breakup, as a function of the incident energy and of the projectile separation energy, is also investigated.

  4. Estimating the ultimate bound and positively invariant set for the Lorenz system and a unified chaotic system

    NASA Astrophysics Data System (ADS)

    Li, Damei; Lu, Jun-An; Wu, Xiaoqun; Chen, Guanrong

    2006-11-01

    To estimate the ultimate bound and positively invariant set for a dynamic system is an important but quite challenging task in general. In this paper, we attempt to investigate the ultimate bound and positively invariant set for two specific systems, the Lorenz system and a unified chaotic system. We derive an ellipsoidal estimate of the ultimate bound and positively invariant set for the Lorenz system, for all the positive values of its parameters a, b and c, and obtain the minimum value of volume for the ellipsoid. Comparing with the best results in the current literature [D. Li, J. Lu, X. Wu, G. Chen, Estimating the bounds for the Lorenz family of chaotic systems, Chaos Solitons Fractals 23 (2005) 529-534; X. Liao, On the global basin of attraction and positively invariant set for the Lorenz chaotic system and its application in chaos control and synchronization, Sci. China Ser. E 34 (2004) 1404-1419], our new results fill up the gap of the estimate for the cases of 0system and its application in chaos control and synchronization, Sci. China Ser. E 34 (2004) 1404-1419]. Furthermore, the estimation derived here contains the results given in [D. Li, J. Lu, X. Wu, G. Chen, Estimating the bounds for the Lorenz family of chaotic systems, Chaos Solitons Fractals 23 (2005) 529-534] and [X. Liao, On the global basin of attraction and positively invariant set for the Lorenz chaotic system and its application in chaos control and synchronization, Sci. China Ser. E 34 (2004) 1404-1419] as special cases. Along the same line, we also provide estimates of cylindrical and ellipsoidal bounds for a unified chaotic system, for its parameter range , and obtain the minimum value of volume for the ellipsoid. The estimate is more accurate than and also extends the result of [D. Li, J. Lu, X. Wu, G. Chen, Estimating the bounds for the Lorenz family of chaotic systems, Chaos

  5. Simple motion systems and Banach spaces associated to uniformly bounded representations

    NASA Astrophysics Data System (ADS)

    Mayer, Matthias; Saller, Christian

    1999-07-01

    Given a uniformly bounded representation of a locally compact group, we consider the closed circled convex hull K of the orbit of a vector. We call K a simple motion system (SMS) and endow its linear hull with the Minkowski functional of K. The representation theory on these ‘SMS-spaces’ is discussed, in particular for C0-representations, for irreducible representations of connected groups and for integrable representations. As an application we give a criterion for the decomposibility of representations.

  6. Some Properties and Stability Results for Sector-Bounded LTI Systems

    NASA Technical Reports Server (NTRS)

    Gupta, Sandeep; Joshi, Suresh M.

    1994-01-01

    This paper presents necessary and sufficient conditions for a linear, time-invariant (LTI) system to be inside sector (n, b) in terms of linear matrix inequalities in its state-space realization matrices, which represents a generalization of similar conditions for bounded H(sub infinity)-norm systems. Further, a weaker definition of LTI systems strictly inside closed sector (a, b) is proposed, and state-space characterization of such systems is presented. Sector conditions for stability of the negative feedback interconnection of two LTI systems and for stability of LTI systems with feedback nonlinearities are investigated using the Lyapunov function approach. It is shown that the proposed weaker conditions for an LTI system to be strictly inside a sector are sufficient to establish closed-loop stability of these systems.

  7. Chromatin-bound nuclear pore components regulate gene expression in higher eukaryotes

    PubMed Central

    Capelson, Maya; Liang, Yun; Schulte, Roberta; Mair, William; Wagner, Ulrich; Hetzer, Martin W.

    2010-01-01

    Nuclear pore complexes have recently been shown to play roles in gene activation, however their potential involvement in metazoan transcription remains unclear. Here we show that the nucleoporins Sec13, Nup98 and Nup88, as well as a group of FG-repeat nucleoporins, bind to the Drosophila genome at functionally distinct loci that often do not represent NE contact sites. While Nup88 localizes to silent loci, Sec13, Nup98 and a subset of FG-repeat nucleoporins bind to developmentally regulated genes undergoing transcription induction. Strikingly, RNAi-mediated knockdown of intranuclear Sec13 and Nup98 specifically inhibits transcription of their target genes and prevents efficient reactivation of transcription after heat shock, suggesting an essential role of NPC components in regulating complex gene expression programs of multicellular organisms. PMID:20144761

  8. Finite Energy and Bounded Actuator Attacks on Cyber-Physical Systems

    SciTech Connect

    Djouadi, Seddik M; Melin, Alexander M; Ferragut, Erik M; Laska, Jason A; Dong, Jin; Drira, Anis

    2015-01-01

    As control system networks are being connected to enterprise level networks for remote monitoring, operation, and system-wide performance optimization, these same connections are providing vulnerabilities that can be exploited by malicious actors for attack, financial gain, and theft of intellectual property. Much effort in cyber-physical system (CPS) protection has focused on protecting the borders of the system through traditional information security techniques. Less effort has been applied to the protection of cyber-physical systems from intelligent attacks launched after an attacker has defeated the information security protections to gain access to the control system. In this paper, attacks on actuator signals are analyzed from a system theoretic context. The threat surface is classified into finite energy and bounded attacks. These two broad classes encompass a large range of potential attacks. The effect of theses attacks on a linear quadratic (LQ) control are analyzed, and the optimal actuator attacks for both finite and infinite horizon LQ control are derived, therefore the worst case attack signals are obtained. The closed-loop system under the optimal attack signals is given and a numerical example illustrating the effect of an optimal bounded attack is provided.

  9. Selection of intrusion detection system threshold bounds for effective sensor fusion

    NASA Astrophysics Data System (ADS)

    Thomas, Ciza; Balakrishnan, Narayanaswamy

    2007-04-01

    The motivation behind the fusion of Intrusion Detection Systems was the realization that with the increasing traffic and increasing complexity of attacks, none of the present day stand-alone Intrusion Detection Systems can meet the high demand for a very high detection rate and an extremely low false positive rate. Multi-sensor fusion can be used to meet these requirements by a refinement of the combined response of different Intrusion Detection Systems. In this paper, we show the design technique of sensor fusion to best utilize the useful response from multiple sensors by an appropriate adjustment of the fusion threshold. The threshold is generally chosen according to the past experiences or by an expert system. In this paper, we show that the choice of threshold bounds according to the Chebyshev inequality priciple performs better. This approach also helps to solve the problem of scalability and has the advantage of failsafe capability. This paper theoretically models the fusion of Intrusion Detection Systems for the purpose of proving the improvement in performance, supplemented with the empirical evaluation. The combination of complementary sensors is shown to detect more attacks than the individual components. Since the individual sensors chosen detect sufficiently different attacks, their result can be merged for improved performance. The combination is done in different ways like (i) taking all the alarms from each system and avoiding duplications, (ii) taking alarms from each system by fixing threshold bounds, and (iii) rule-based fusion with a priori knowledge of the individual sensor performance. A number of evaluation metrics are used, and the results indicate that there is an overall enhancement in the performance of the combined detector using sensor fusion incorporating the threshold bounds and significantly better performance using simple rule-based fusion.

  10. Hydrogen Bound Complexes with Tropolone: Binding Motifs, Barrier Heights, and the Search for Bifurcating Systems

    NASA Astrophysics Data System (ADS)

    Nemchick, Deacon; Chew, Kathryn; Vaccaro, Patrick

    2014-06-01

    The potentially frustrated transfer of a proton between the hydroxylic (proton-donating) and ketonic (proton-accepting) oxygen atom centers in tropolone (TrOH) long has served as a model system for the study of coherent (symmetrical) proton-transfer events. A litany of hydrogen-bound complexes [TrOH \\cdot Xn] can be formed in situ by docking amphoteric ligands onto the TrOH substrate under supersonic free-jet expansion conditions. Binary (n = 1) and higher order (n = 2, 3, ldots) complexes formed with formic acid, hydrogen fluoride, acetic acid and propiolic acid (X = FA, HF, AA, and PA) have been synthesized and interrogated using a variety of spectroscopic probes built upon the intense ˜{A1}B2-˜{X1}{A}1 (π *←π) near-ultraviolet absorption system of bare tropolone, thereby providing vibronically resolved information through combined use of laser-induced fluorescence (LIF), dispersed fluorescence (DF), fluorescence hole-burning (FHB), and stimulated emission pumping (SEP) methods. Experimental results reveal the propensity for binary complexes to adopt a higher-energy external binding motif (ligand attached to the seven membered aromatic ring) over the energetically preferred internal form (ligand bound to the O-H\\cdotsO reaction center), where the latter cleft-bound species can undergo unique symmetric (coherent) double proton-transfer reactions. These findings will be discussed in light of supporting quantum-chemical calculations.

  11. Dynamic Analysis of Nuclear Energy System Strategies

    Energy Science and Technology Software Center (ESTSC)

    2004-06-17

    DANESS is an integrated process model for nuclear energy systems allowing the simulation of multiple reactors and fuel cycles in a continuously changing nuclear reactor park configuration. The model is energy demand driven and simulates all nuclear fuel cycle facilites, up to 10 reactors and fuels. Reactor and fuel cycle facility history are traced and the cost of generating energy is calculated per reactor and for total nuclear energy system. The DANESS model aims atmore » performing dynamic systems analysis of nuclear energy development used for integrated analysis of development paths for nuclear energy, parameter scoping for new nuclear energy systems, economic analysis of nuclear energy, government role analysis, and education.« less

  12. Optical model parallel description of elastic, fusion and breakup cross sections for systems with weakly bound projectiles

    NASA Astrophysics Data System (ADS)

    Gómez Camacho, A.; Gomes, P. R. S.; Lubian, J.; Aguilera, E. F.

    2014-03-01

    A brief description is presented of the results obtained in recent years for the simultaneous analysis of elastic and fusion cross section data of nuclear reactions for several nuclear systems with weakly bound and halo projectiles. The method used in this description, consists of simultaneously determine the parameters of fusion UF and direct reaction UDR polarization potentials of Woods-Saxon geometric shapes, that fit the elastic and fusion data. As a matter of fact, UFis an energy dependent potential, with real VF and imaginary WFcomponents, that is responsible for fusion reactions. Similarly, UDR is also energy dependent with real VDR and imaginary WDR parts, that accounts for direct reactions. A general finding for all the systems presented is that, the real and imaginary parts of the fusion potential and direct reaction potentials, are related by a dispersion relation and their energy dependence around and below the Coulomb barrier, show the so-called Breakup Threshold Anomaly. The effect of breakup reactions on fusion cross sections is studied by analyzing the separate effect of the absorption potential WDR and the fusion barrier rising produced by VDR.

  13. Bound-state eigenenergy outside and inside the continuum for unstable multilevel systems

    NASA Astrophysics Data System (ADS)

    Miyamoto, Manabu

    2005-12-01

    The eigenvalue problem for the dressed bound state of unstable multilevel systems is examined both outside and inside the continuum, based on the N -level Friedrichs model, which describes the couplings between the discrete levels and the continuous spectrum. It is shown that a bound-state eigenenergy always exists below each of the discrete levels that lie outside the continuum. Furthermore, by strengthening the couplings gradually, the eigenenergy corresponding to each of the discrete levels inside the continuum finally emerges. On the other hand, the absence of the eigenenergy inside the continuum is proved in weak but finite coupling regimes, provided that each of the form factors that determine the transition between some definite level and the continuum does not vanish at that energy level. An application to the spontaneous emission process for the hydrogen atom interacting with the electromagnetic field is demonstrated.

  14. Free nuclear precession gradiometer system

    SciTech Connect

    Hinton, G. F.

    1985-10-08

    A free nuclear precession gradiometer uses a fluid sample surrounded by a coil the fluid sample containing one or more nuclear species which display a magnetic moment. Current in the coil polarizes the nucleii, which when the current is abruptly terminated precess coherently about the earth's magnetic field. The exact frequency generated is a precise measure of the absolute value of the earth's magnetic field. The signal is in the form of a damped sinusoid with the rate of decay being a function of gradients in the ambient magnetic field. Two vector magnetometers are mounted rigidly on the sensor at the right angles to each other and to the earth's magnetic field. A servo system continuously orients the sensor in a two-axis gimbal system to reduce the output of the vector magnetometers to zero. The instrument is polarized, a counter is triggered to make the frequency measurement, and the signal is analyzed by determining the average amplitude of the signal over a precise interval of time. The result is simultaneous measurement of total intensity and total gradient.

  15. Bounding criticality safety analyses for shipments of unconfigured spent nuclear fuel

    SciTech Connect

    Lichtenwalter, J.J.; Parks, C.V.

    1998-06-01

    In November 1996, a request was made to the US Department of Energy for a waiver for three shipments of spent nuclear fuel (SNF) from Oak Ridge National Laboratory (ORNL) to the Savannah River Site (SRS) in the US NRC certified BMI-1 cask (CoC 5957). Although the post-irradiation fissile mass (based on chemical assays) in each shipment was less than 800 g, a criticality safety analysis was needed because the pre-irradiation mass exceeded 800 g, the fissile material limit in the CoC. The analyses were performed on SNF consisting of aluminum-clad U{sub 3}O{sub 8}, UAl{sub x}, and U{sub 3}Si{sub 2} plates, fragments and pieces that had been irradiated at ORNL during the Reduced Enrichment Research and Test Reactor Program of the 1980s. The highlights of the approach used to analyze this unique SNF and the benefits of the waiver are presented in this paper.

  16. Indirect M-MRAC for Systems with Time Varying Parameters and Bounded Disturbances

    NASA Technical Reports Server (NTRS)

    Stepanyan, Vahram; Krishnakumar, Kalmanje

    2012-01-01

    The paper presents a prediction-identification model based adaptive control method for uncertain systems with time varying parameters in the presence of bounded external disturbances. The method guarantees desired tracking performance for the system s state and input signals. This is achieved by feeding back the state prediction error to the identification model. It is shown that the desired closed-loop properties are obtained with fast adaptation when the error feedback gain is selected proportional to the square root of the adaptation rate. The theoretical findings are confirmed via a simulation example.

  17. Launch approval considerations for space nuclear power systems

    NASA Astrophysics Data System (ADS)

    Skinner, Dawn; Phillips, J. Mark

    1998-01-01

    Nuclear Safety Launch Approval is the US process by which approval is granted from the Executive Branch for the use of nuclear materials in space. It involves analyses utilizing a combination of theoretical calculation and empirical test data, by which the launch of a space nuclear system is demonstrated to have acceptable consequences in terms of radiological risk. Many factors influence the launch approval process and it's complexity. Historical launch approval examples are discussed as well as considerations for mission design, power source design, launch vehicle selection and spacecraft design which may simplify the analyses for launch approval. Factors which influence the complexity of the analyses as well as factors which can bound the analyses are discussed.

  18. Two-dimensional nuclear magnetic resonance analysis of a labeled peptide bound to a class II major histocompatibility complex molecule.

    PubMed

    Driscoll, P C; Altman, J D; Boniface, J J; Sakaguchi, K; Reay, P A; Omichinski, J G; Appella, E; Davis, M M

    1993-07-20

    The formation of peptide/major histocompatibility complex (MHC) complexes and their subsequent recognition by T cells is a pivotal event in the initiation of an immune response. While X-ray crystal structures are now available for class I MHC/peptide complexes, little detailed structural information is known about the class II MHC equivalent, and there are no solution structure data for either. A 16 amino acid residue moth cytochrome c peptide (residues 88 to 103) was 13C-labeled for two-dimensional isotope-edited NMR analysis. The peptide was labeled either selectively in the methyl groups of alanine residues or uniformly at every carbon position, and bound to unlabeled soluble mouse I-Ek class II MHC molecules. Although alpha-helical in the native cytochrome c protein and with no uniform structure in solution, the peptide is bound to the I-Ek molecule with the alpha-carbon atoms of the 11 C-terminal residues held in the binding groove. This indicates that the class II MHC peptide binding site is somewhat larger than that of class I MHC molecules (> or = 11 amino acid residues versus 8 to 10 amino acid residues), consistent with recent data on eluted peptides. Despite the large size of the complex (approximately 70 kDa), nuclear Overhauser effects are clearly detectable between peptide side-chains and the MHC molecule. Indications of the buried or exposed nature of particular side-chains within the bound peptide are derived from the NMR data and these are used together with information from previous biological studies to propose a crude model of the interaction of the peptide with the groove of the MHC molecule. We find no evidence for a conformational change in the peptide/MHC complex in the spectra at pH 5.0 versus pH 7.0, despite a 40-fold faster on-rate for the peptide at the lower pH value. PMID:8393933

  19. Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe

    NASA Astrophysics Data System (ADS)

    Heisterkamp, F.; Greilich, A.; Zhukov, E. A.; Kirstein, E.; Kazimierczuk, T.; Korenev, V. L.; Yugova, I. A.; Yakovlev, D. R.; Pawlis, A.; Bayer, M.

    2015-12-01

    Optically induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a transverse nuclear spin polarization, which is detected as a change of the Larmor precession frequency of the donor-bound electron spins. The frequency shift in dependence on the transverse magnetic field exhibits a pronounced dispersion-like shape with resonances at the fields of nuclear magnetic resonance of the constituent zinc and selenium isotopes. It is studied as a function of external parameters, particularly of constant and radio frequency external magnetic fields. The width of the resonance and its shape indicate a strong spatial inhomogeneity of the nuclear spin polarization in the vicinity of a fluorine donor. A mechanism of optically induced nuclear spin polarization is suggested based on the concept of resonant nuclear spin cooling driven by the inhomogeneous Knight field of the donor-bound electron.

  20. Fieldable Nuclear Material Identification System

    SciTech Connect

    Radle, James E; Archer, Daniel E; Carter, Robert J; Mullens, James Allen; Mihalczo, John T; Britton Jr, Charles L; Lind, Randall F; Wright, Michael C

    2010-01-01

    The Fieldable Nuclear Material Identification System (FNMIS), funded by the NA-241 Office of Dismantlement and Transparency, provides information to determine the material attributes and identity of heavily shielded nuclear objects. This information will provide future treaty participants with verifiable information required by the treaty regime. The neutron interrogation technology uses a combination of information from induced fission neutron radiation and transmitted neutron imaging information to provide high confidence that the shielded item is consistent with the host's declaration. The combination of material identification information and the shape and configuration of the item are very difficult to spoof. When used at various points in the warhead dismantlement sequence, the information complimented by tags and seals can be used to track subassembly and piece part information as the disassembly occurs. The neutron transmission imaging has been developed during the last seven years and the signature analysis over the last several decades. The FNMIS is the culmination of the effort to put the technology in a usable configuration for potential treaty verification purposes.

  1. Materials in space nuclear power systems

    SciTech Connect

    Cooper, R.H.; Moore, J.P.

    1991-01-01

    Man's presence in space has been limited by the availability of reliable lightweight sources of power. Over the course of the last 30 years, a variety of space nuclear power systems have been designed and, in some cases, built and flown. Although a number of technology issues effect the overall performance of these systems, technical issues associated with the materials of construction have most often been a major limitation in obtaining the desired system performance goals. This paper will review selected materials limitations associated with the three major nuclear power systems being considered at this time: radioisotope power, nuclear power, and nuclear propulsion systems.

  2. Hyperspherical three-body model calculation for the bound 3,1S-states of Coulombic systems

    NASA Astrophysics Data System (ADS)

    Khan, Md. Abdul

    2015-11-01

    In this paper, hyperspherical three-body model formalism has been applied for the calculation of energies of the low-lying bound 3S-states of neutral helium and helium like Coulombic three-body systems having nuclear charge (z) in the range 2 ≤ Z ≤ 92. Energies of 1S-states are also calculated for those having nuclear charge in the range 14 ≤ Z ≤ 92. The calculation of the coupling potential matrix elements of the two-body potentials has been simplified by the use of Raynal-Revai Coefficients (RRC). The three-body wave function in the Schrödinger equation when expanded in terms of hyperspherical harmonics (HH), leads to an infinite set of coupled differential equation (CDE) which for practical purposes is truncated to a finite set and the truncated set of CDE’s are solved by renormalized Numerov method (RNM) to get the energy (E). The calculated energy is compared with the ones of the literature.

  3. Capture zone of a multi-well system in bounded peninsula-shaped aquifers.

    PubMed

    Zarei-Doudeji, Somayeh; Samani, Nozar

    2014-08-01

    In this paper we present the equation of capture zone for multi-well system in peninsula-shaped confined and unconfined aquifers. The aquifer is rectangular in plan view, bounded along three sides, and extends to infinity at the fourth side. The bounding boundaries are either no-flow (impervious) or in-flow (constant head) so that aquifers with six possible boundary configurations are formed. The well system is consisted of any number of extraction or injection wells or combination of both with any flow rates. The complex velocity potential equations for such a well-aquifer system are derived to delineate the capture envelop. Solutions are provided for the aquifers with and without a uniform regional flow of any directions. The presented equations are of general character and have no limitations in terms of well numbers, positions and types, extraction/injection rate, and regional flow rate and direction. These solutions are presented in form of capture type curves which are useful tools in hands of practitioners to design in-situ groundwater remediation systems, to contain contaminant plumes, to evaluate the surface-subsurface water interaction and to verify numerical models. PMID:24973506

  4. NASA Missions Enabled by Space Nuclear Systems

    NASA Technical Reports Server (NTRS)

    Scott, John H.; Schmidt, George R.

    2009-01-01

    This viewgraph presentation reviews NASA Space Missions that are enabled by Space Nuclear Systems. The topics include: 1) Space Nuclear System Applications; 2) Trade Space for Electric Power Systems; 3) Power Generation Specific Energy Trade Space; 4) Radioisotope Power Generation; 5) Radioisotope Missions; 6) Fission Power Generation; 7) Solar Powered Lunar Outpost; 8) Fission Powered Lunar Outpost; 9) Fission Electric Power Generation; and 10) Fission Nuclear Thermal Propulsion.

  5. Revealing the flux: Using processed Husimi maps to visualize dynamics of bound systems and mesoscopic transport

    NASA Astrophysics Data System (ADS)

    Mason, Douglas J.; Borunda, Mario F.; Heller, Eric J.

    2015-04-01

    We elaborate upon the "processed Husimi map" representation for visualizing quantum wave functions using coherent states as a measurement of the local phase space to produce a vector field related to the probability flux. Adapted from the Husimi projection, the processed Husimi map is mathematically related to the flux operator under certain limits but offers a robust and flexible alternative since it can operate away from these limits and in systems that exhibit zero flux. The processed Husimi map is further capable of revealing the full classical dynamics underlying a quantum wave function since it reverse engineers the wave function to yield the underlying classical ray structure. We demonstrate the capabilities of processed Husimi maps on bound systems with and without electromagnetic fields, as well as on open systems on and off resonance, to examine the relationship between closed system eigenstates and mesoscopic transport.

  6. a Search for a Bound Sigma Hypernuclei in the a = 3 System

    NASA Astrophysics Data System (ADS)

    Barakat, Mohamad Basem

    The search for a bound Sigma hypernuclei state in the A = 3, 4 systems was undertaken at the AGS using the Hypernuclear Spectrometer, "MOBY DICK" and the secondary Kaon beam line, LESBII at an incident momentum of 600 Mev/c. Both liquid ^3He and ^4He targets were used. An analysis of the ^{3}He(K ^{-}/,pi^{+ })X data tagged by two charged particles decay mode of the recoil system unveiled some strength in the EE (Excitation Energy) spectrum just below the Sigma^-D threshold. On the other hand, Monte Carlo simulation of the various decay modes of the formed recoil system revealed that the above strength is consistent with the formation of a Sigma ^circ nn system. A theoretical background and experimental arrangements are given in Chapters one and two; while a detailed analysis and discussion of the ^3He(K^-,pi^+)X reaction data are presented in Chapters three and four respectively.

  7. Nuclear electric propulsion reactor control systems status

    NASA Technical Reports Server (NTRS)

    Ferg, D. A.

    1973-01-01

    The thermionic reactor control system design studies conducted over the past several years for a nuclear electric propulsion system are described and summarized. The relevant reactor control system studies are discussed in qualitative terms, pointing out the significant advantages and disadvantages including the impact that the various control systems would have on the nuclear electric propulsion system design. A recommendation for the reference control system is made, and a program for future work leading to an engineering model is described.

  8. On bound state computations in three- and four-electron atomic systems

    SciTech Connect

    Frolov, A. M. Wardlaw, D. M.

    2010-07-15

    A variational approach is developed for bound state calculations in three- and four-electron atomic systems. This approach can be applied to determine, in principle, an arbitrary bound state in three- and four-electron ions and atoms. Our variational wave functions are constructed from four- and five-body Gaussoids that respectively depend on six (r{sub 12}, r{sub 13}, r{sub 14}, r{sub 23}, r{sub 24}, r{sub 34}) and ten (r{sub 12}, r{sub 13}, r{sub 14}, r{sub 15}, r{sub 23}, r{sub 24}, r{sub 25}, r{sub 34}, r{sub 35} and r{sub 45}) relative coordinates. The approach allows operating with the more than one electron spin functions. In particular, the trial wave functions for the {sup 1}S states in four-electron atomic systems include the two independent spin functions {chi}{sub 1} = {alpha}{beta}{alpha}{beta} + {beta}{alpha}{beta}{alpha} - {beta}{alpha}{alpha}{beta} - {alpha}{beta}{beta}{alpha} and {chi}{sub 2} = 2{alpha}{alpha}{beta}{beta} + 2{beta}{beta}{alpha}{alpha} - {beta}{alpha}{alpha}{beta} - {alpha}{beta}{beta}{alpha} - {beta}{alpha}{beta}{alpha} - {alpha}{beta}{alpha}{beta}. We also discuss the construction of variational wave functions for the excited 2{sup 3}S states in four- electron atomic systems.

  9. Formation of Peptide Bound Pyrraline in the Maillard Model Systems with Different Lys-Containing Dipeptides and Tripeptides.

    PubMed

    Liang, Zhili; Li, Lin; Qi, Haiping; Wan, Liting; Cai, Panfu; Xu, Zhenbo; Li, Bing

    2016-01-01

    Peptide-bound advanced glycation end-products (peptide-bound AGEs) can be formed when peptides are heated with reducing saccharides. Pyrraline is the one of most commonly studied AGEs in foods, but the relative importance of the precursor peptide structure is uncertain. In the present study, model systems were prepared by heating peptides with glucose from 60 °C to 220 °C for up to 65 min, and the amounts of peptide-bound pyrraline formed were monitored to evaluate the effect of the neighboring amino acids on the peptide-bound pyrraline formation. The physico-chemical properties were introduced to explore the quantitative structure-reactivity relationships between physicochemical properties and peptide bound formation. 3-DG content in dipeptide-glucose model system was higher than that in the corresponding tripeptide-glucose model systems. Dipeptides produced higher amounts of peptide-bound pyrraline than the corresponding tripeptides. The peptide-bound pyrraline and 3-DG production were influenced by the physico-chemical properties of the side chain of amino acids adjacent to Lys in the following order: Lys-Leu/glucose > Lys-Ile/glucose > Lys-Val/ glucose > Lys-Thr/glucose > Lys-Ser/glucose > Lys-Ala/ glucose > Lys-Gly/glucose; Lys-Leu-Gly/glucose > Lys-Ile-Gly/glucose > Lys-Val-Gly/glucose > Lys-Thr-Gly/glucose > Lys-Ser-Gly/glucose > Lys-Ala-Gly/glucose > Lys-Gly-Gly/glucose. For the side chain of amino acids adjacent to Lys in dipeptides, residue volume, polarizability, molecular volume and localized electrical effect were positively related to the yield of peptide bound pyrraline, while hydrophobicity and pKb were negatively related to the yield of peptide bound pyrraline. In terms of side chain of amino acid adjacent to Lys in tripeptides, a similar result was observed, except hydrophobicity was positively related to the yield of peptide bound pyrraline. PMID:27070556

  10. Strichartz Estimates and Moment Bounds for the Relativistic Vlasov-Maxwell System

    NASA Astrophysics Data System (ADS)

    Luk, Jonathan; Strain, Robert M.

    2016-01-01

    We consider the relativistic Vlasov-Maxwell system with data of unrestricted size and without compact support in momentum space. In the two-dimensional and the two-and-a-half-dimensional cases, Glassey-Schaeffer proved (Commun Math Phys 185:257-284, 1997; Arch Ration Mech Anal 141:331-354, 1998; Arch Ration Mech Anal. 141:355-374, 1998) that for regular initial data with compact momentum support this system has unique global in time classical solutions. In this work we do not assume compact momentum support for the initial data and instead require only that the data have polynomial decay in momentum space. In the two-dimensional and the two-and-a-half-dimensional cases, we prove the global existence, uniqueness and regularity for solutions arising from this class of initial data. To this end we use Strichartz estimates and prove that suitable moments of the solution remain bounded. Moreover, we obtain a slight improvement of the temporal growth of the {L^∞_x} norms of the electromagnetic fields compared to Glassey and Schaeffer (Commun Math Phys 185:257-284, 1997; Arch Ration Mech Anal 141:355-374, 1998). In the three-dimensional case, we apply Strichartz estimates and moment bounds to show that a regular solution can be extended as long as {{|p_0^{θ} f |_{LqxL^1p}}} remains bounded for {θ > 2/q}, {2 < q ≤q ∞}. This improves previous results of Pallard (Indiana Univ Math J 54(5):1395-1409, 2005; Commun Math Sci 13(2):347-354, 2015).

  11. Computation Results from a Parametric Study to Determine Bounding Critical Systems of Homogeneously Water-Moderated Mixed Plutonium--Uranium Oxides

    SciTech Connect

    Shimizu, Y.

    2001-01-11

    This report provides computational results of an extensive study to examine the following: (1) infinite media neutron-multiplication factors; (2) material bucklings; (3) bounding infinite media critical concentrations; (4) bounding finite critical dimensions of water-reflected and homogeneously water-moderated one-dimensional systems (i.e., spheres, cylinders of infinite length, and slabs that are infinite in two dimensions) that were comprised of various proportions and densities of plutonium oxides and uranium oxides, each having various isotopic compositions; and (5) sensitivity coefficients of delta k-eff with respect to critical geometry delta dimensions were determined for each of the three geometries that were studied. The study was undertaken to support the development of a standard that is sponsored by the International Standards Organization (ISO) under Technical Committee 85, Nuclear Energy (TC 85)--Subcommittee 5, Nuclear Fuel Technology (SC 5)--Working Group 8, Standardization of Calculations, Procedures and Practices Related to Criticality Safety (WG 8). The designation and title of the ISO TC 85/SC 5/WG 8 standard working draft is WD 14941, ''Nuclear energy--Fissile materials--Nuclear criticality control and safety of plutonium-uranium oxide fuel mixtures outside of reactors.'' Various ISO member participants performed similar computational studies using their indigenous computational codes to provide comparative results for analysis in the development of the standard.

  12. Nuclear Data Needs for Generation IV Nuclear Energy Systems

    NASA Astrophysics Data System (ADS)

    Rullhusen, Peter

    2006-04-01

    Nuclear data needs for generation IV systems. Future of nuclear energy and the role of nuclear data / P. Finck. Nuclear data needs for generation IV nuclear energy systems-summary of U.S. workshop / T. A. Taiwo, H. S. Khalil. Nuclear data needs for the assessment of gen. IV systems / G. Rimpault. Nuclear data needs for generation IV-lessons from benchmarks / S. C. van der Marck, A. Hogenbirk, M. C. Duijvestijn. Core design issues of the supercritical water fast reactor / M. Mori ... [et al.]. GFR core neutronics studies at CEA / J. C. Bosq ... [et al]. Comparative study on different phonon frequency spectra of graphite in GCR / Young-Sik Cho ... [et al.]. Innovative fuel types for minor actinides transmutation / D. Haas, A. Fernandez, J. Somers. The importance of nuclear data in modeling and designing generation IV fast reactors / K. D. Weaver. The GIF and Mexico-"everything is possible" / C. Arrenondo Sánchez -- Benmarks, sensitivity calculations, uncertainties. Sensitivity of advanced reactor and fuel cycle performance parameters to nuclear data uncertainties / G. Aliberti ... [et al.]. Sensitivity and uncertainty study for thermal molten salt reactors / A. Biduad ... [et al.]. Integral reactor physics benchmarks- The International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPHEP) / J. B. Briggs, D. W. Nigg, E. Sartori. Computer model of an error propagation through micro-campaign of fast neutron gas cooled nuclear reactor / E. Ivanov. Combining differential and integral experiments on [symbol] for reducing uncertainties in nuclear data applications / T. Kawano ... [et al.]. Sensitivity of activation cross sections of the Hafnium, Tanatalum and Tungsten stable isotopes to nuclear reaction mechanisms / V. Avrigeanu ... [et al.]. Generating covariance data with nuclear models / A. J. Koning. Sensitivity of Candu-SCWR reactors physics calculations to nuclear data files / K. S

  13. Non-Nuclear NEP System Testing

    NASA Astrophysics Data System (ADS)

    Hrbud, Ivana; Goodfellow, Keith; van Dyke, Melissa; Houts, Mike

    2003-01-01

    The Safe Affordable Fission Engine (SAFE) test series addresses Phase 1 Space Fission Systems issues in particular non-nuclear testing and system integration issues leading to the testing and non-nuclear demonstration of a 400-kW fully integrated flight unit. The first part of the SAFE 30 test series demonstrated operation of the simulated nuclear core and heat pipe system. Experimental data acquired in a number of different test scenarios will validate existing computational models, demonstrated system flexibility (fast start-ups, multiple start-ups/shut downs), simulate predictable failure modes and operating environments. The objective of the second part is to demonstrate an integrated propulsion system consisting of a core, conversion system and a thruster where the system converts thermal heat into jet power. This end-to-end system demonstration sets a precedent for ground testing of nuclear electric propulsion systems. The paper describes the SAFE 30 end-to-end system demonstration and its subsystems.

  14. Shot noise in a quantum dot system coupled with Majorana bound states

    NASA Astrophysics Data System (ADS)

    Chen, Qiao; Chen, Ke-Qiu; Zhao, Hong-Kang

    2014-08-01

    We investigate the spectral density of shot noise and current for the system of a quantum dot coupled to Majorana bound states (MBS) employing the nonequilibrium Green’s function. The Majorana bound states at the end of the wire strongly affect the shot noise. There are two types of coupling in the system: dot-MBS and MBS-MBS coupling. The curves of shot noise and current versus coupling strength have novel steps owing to the energy-level splitting caused by dot-MBS coupling. The magnitude of these steps increases with the strength of dot-MBS coupling λ but decreases with the strength of MBS-MBS coupling. The steps shift toward the large ∣eV∣ region as λ or ɛM increases. In addition, dot-MBS coupling enhances the shot noise while MBS-MBS coupling suppresses the shot noise. In the absence of MBS-MBS coupling, a sharp jump emerges in the curve of the Fano factor at zero bias owing to the differential conductance being reduced by a factor of 1/2. This provides a novel technique for the detection of Majorana fermions.

  15. Shot noise in a quantum dot system coupled with Majorana bound states.

    PubMed

    Chen, Qiao; Chen, Ke-Qiu; Zhao, Hong-Kang

    2014-08-01

    We investigate the spectral density of shot noise and current for the system of a quantum dot coupled to Majorana bound states (MBS) employing the nonequilibrium Green's function. The Majorana bound states at the end of the wire strongly affect the shot noise. There are two types of coupling in the system: dot-MBS and MBS-MBS coupling. The curves of shot noise and current versus coupling strength have novel steps owing to the energy-level splitting caused by dot-MBS coupling. The magnitude of these steps increases with the strength of dot-MBS coupling λ but decreases with the strength of MBS-MBS coupling. The steps shift toward the large ∣eV∣ region as λ or ϵ(M) increases. In addition, dot-MBS coupling enhances the shot noise while MBS-MBS coupling suppresses the shot noise. In the absence of MBS-MBS coupling, a sharp jump emerges in the curve of the Fano factor at zero bias owing to the differential conductance being reduced by a factor of 1/2. This provides a novel technique for the detection of Majorana fermions. PMID:25016999

  16. Nuclear Space Power Systems Materials Requirements

    SciTech Connect

    Buckman, R.W. Jr.

    2004-02-04

    High specific energy is required for space nuclear power systems. This generally means high operating temperatures and the only alloy class of materials available for construction of such systems are the refractory metals niobium, tantalum, molybdenum and tungsten. The refractory metals in the past have been the construction materials selected for nuclear space power systems. The objective of this paper will be to review the past history and requirements for space nuclear power systems from the early 1960's through the SP-100 program. Also presented will be the past and present status of refractory metal alloy technology and what will be needed to support the next advanced nuclear space power system. The next generation of advanced nuclear space power systems can benefit from the review of this past experience. Because of a decline in the refractory metal industry in the United States, ready availability of specific refractory metal alloys is limited.

  17. Nuclear Space Power Systems Materials Requirements

    NASA Astrophysics Data System (ADS)

    Buckman, R. W.

    2004-02-01

    High specific energy is required for space nuclear power systems. This generally means high operating temperatures and the only alloy class of materials available for construction of such systems are the refractory metals niobium, tantalum, molybdenum and tungsten. The refractory metals in the past have been the construction materials selected for nuclear space power systems. The objective of this paper will be to review the past history and requirements for space nuclear power systems from the early 1960's through the SP-100 program. Also presented will be the past and present status of refractory metal alloy technology and what will be needed to support the next advanced nuclear space power system. The next generation of advanced nuclear space power systems can benefit from the review of this past experience. Because of a decline in the refractory metal industry in the United States, ready availability of specific refractory metal alloys is limited.

  18. NUCLEAR ENERGY SYSTEM COST MODELING

    SciTech Connect

    Francesco Ganda; Brent Dixon

    2012-09-01

    The U.S. Department of Energy’s Fuel Cycle Technologies (FCT) Program is preparing to perform an evaluation of the full range of possible Nuclear Energy Systems (NES) in 2013. These include all practical combinations of fuels and transmuters (reactors and sub-critical systems) in single and multi-tier combinations of burners and breeders with no, partial, and full recycle. As part of this evaluation, Levelized Cost of Electricity at Equilibrium (LCAE) ranges for each representative system will be calculated. To facilitate the cost analyses, the 2009 Advanced Fuel Cycle Cost Basis Report is being amended to provide up-to-date cost data for each step in the fuel cycle, and a new analysis tool, NE-COST, has been developed. This paper explains the innovative “Island” approach used by NE-COST to streamline and simplify the economic analysis effort and provides examples of LCAE costs generated. The Island approach treats each transmuter (or target burner) and the associated fuel cycle facilities as a separate analysis module, allowing reuse of modules that appear frequently in the NES options list. For example, a number of options to be screened will include a once-through uranium oxide (UOX) fueled light water reactor (LWR). The UOX LWR may be standalone, or may be the first stage in a multi-stage system. Using the Island approach, the UOX LWR only needs to be modeled once and the module can then be reused on subsequent fuel cycles. NE-COST models the unit operations and life cycle costs associated with each step of the fuel cycle on each island. This includes three front-end options for supplying feedstock to fuel fabrication (mining/enrichment, reprocessing of used fuel from another island, and/or reprocessing of this island’s used fuel), along with the transmuter and back-end storage/disposal. Results of each island are combined based on the fractional energy generated by each islands in an equilibrium system. The cost analyses use the probability

  19. Friedel phase discontinuity and bound states in the continuum in quantum dot systems

    NASA Astrophysics Data System (ADS)

    Solís, B.; Ladrón de Guevara, M. L.; Orellana, P. A.

    2008-06-01

    In this Letter we study the Friedel phase of the electron transport in two different systems of quantum dots which exhibit bound states in the continuum (BIC). The Friedel phase jumps abruptly in the energies of the BICs, which is associated to the vanishing width of these states, as shown by Friedrich and Wintgen in [H. Friedrich, D. Wintgen, Phys. Rev. A 31 (1985) 3964]. This odd behavior of the Friedel phase has consequences in the charge through the Friedel sum rule. Namely, if the energy of the BIC drops under the Fermi energy the charge changes abruptly in a unity. We show that this behavior closely relates to discontinuities in the conductance predicted for interacting quantum dot systems.

  20. Leader-following consensus of high-order multi-agent linear systems with bounded transmission channels

    NASA Astrophysics Data System (ADS)

    Ni, Wei; Xiong, Chun; Yang, Jie

    2013-09-01

    The leader-following consensus of high-order multi-agent linear systems with bounded transmission channels is considered. Agents modelled as LTI dynamics exchange information according to a network which can be described as a graph with agents as its vertices and information transmission channels as its edges. The transmission channels are bounded. The objective is leader-following in the sense that the state of all agents should converge to that of the leader vehicle. Detailed analysis of the leader-following consensus under bounded transmission channels is investigated for both fixed and switching network topologies.

  1. Analysis and control of uncertain/nonlinear systems in the presence of bounded disturbance inputs

    NASA Astrophysics Data System (ADS)

    Pancake, Trent Alan

    2000-10-01

    Real world dynamic systems are frequently subjected to unknown disturbance inputs or perturbations. These inputs are difficult to model but must be taken into account in system analysis and control design, otherwise the integrity of the system could be compromised. When analyzing or controlling a system subjected to these types of disturbances, one is quite often concerned with the peak magnitude of some performance output. Clearly the peak magnitude of important variables is of concern in many engineering systems. This thesis begins by introducing the concept of Linfinity stability with a level of performance gamma. For zero initial state, gamma is an upper bound on the Linfinity gain of the system, that is, the gain of the system when viewed as an operator acting on Linfinity inputs and producing L infinity outputs. Using a Lyapunov based approach, a result which yields a sufficient condition for our notion of Linfinity stability is introduced. This condition is applied to a variety of classes uncertain/nonlinear systems. These classes are characterized as polytopic uncertain/nonlinear systems, a general class of uncertain/nonlinear systems and general polytopic uncertain/nonlinear systems. For each of these classes this thesis states a bunch of linear matrix inequalities which, if satisfied, guarantee Linfinity stability with a level of performance. This thesis also considers systems in which one cannot guarantee Linfinity stability for the entire state-space. To this end, the notion of local Linfinity stable with level of performance gamma is introduced. These analysis results are then used to develop state-feedback controllers. The results in this thesis can be used to design disturbance attenuation controllers for the aforementioned classes of systems. Numerous examples are used to illustrate the results of the thesis.

  2. Stochastic resonance in a tumor-immune system subject to bounded noises and time delay

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Mei, Dong-Cheng

    2014-12-01

    Immunotherapy is one of the most recent approaches in cancer therapy. A mathematical model of tumor-immune interaction, subject to a periodic immunotherapy treatment (imitated by a periodic signal), correlative and bounded stochastic fluctuations and time delays, is investigated by numerical simulations for its signal power amplification (SPA). Within the tailored parameter regime, the synchronous response of tumor growth to the immunotherapy, stochastic resonance (SR), versus both the noises and delays is obtained. The details are as follows (i) the peak values of SPA versus the noise intensity (A) in the proliferation term of tumor cells decrease as the frequency of periodic signal increases, i.e. an increase of the frequency restrains the SR; (ii) an increase of the amplitude of periodic signal restrains the SR versus A, but boosts up the SR versus the noise intensity B in the immune term; (iii) there is an optimum cross-correlated degree between the two bounded noises, at which the system exhibits the strongest SR versus the delay time τα(the reaction time of tumor cell population to their surrounding environment constraints); (iv) upon increasing the delay time τα, double SR versus the delay time τβ (the time taken by both the tumor antigen identification and tumor-stimulated proliferation of effectors) emerges. These results may be helpful for an immunotherapy treatment for the sufferer.

  3. Statistical density model for composite system scattering: Modified ensemble densities and bounded amplitudes

    NASA Astrophysics Data System (ADS)

    Hahn, Y. K.

    2016-09-01

    A statistical density model for composite system scattering is formulated, by incorporating the ensemble density functional approach in describing the correlation dynamics during the collision. The principal difficulty of non-integrable propagating waves is first resolved by treating the open and closed channels separately; only the closed channel part does allow a density description. The unique open/closed channel separation adopted here allows not only the closed channel Hamiltonian MQ to support integrable densities, but also to establish the important bounds on the scattering amplitude. A modified ensemble energy functional for the MQ is constructed, and the statistical densities ρmtQ for the closed channels are generated. The scattering amplitude is then formulated in terms of the ρmtQ and the coefficients of variation that connect the closed channels to the asymptotic source. Evaluation of the amplitude integrals requires the determinantal functions deduced from the ρmtQ, which also leads to a coupled channel approach. The bound property of the amplitude allows variational optimization of the coefficients. Approximate procedures for securing the orthogonality of the MQ and for evaluation of the source term itself are discussed, including a judicious choice of configurations with zero and one inner-shell holes. Validity of the several critical modifications introduced is assessed.

  4. Multimegawatt nuclear power systems for nuclear electric propulsion

    NASA Technical Reports Server (NTRS)

    George, Jeffrey A.

    1991-01-01

    Results from systems analysis studies of multimegawatt nuclear power systems are presented for application to nuclear electric propulsion. Specific mass estimates are presented for nearer term SP-100 reactor-based potassium Rankine and Brayton power systems for piloted and cargo missions. Growth SP-100/Rankine systems were found to range from roughly 7 to 10 kg/kWe specific mass depending on full power life requirements. The SP-100/Rankine systems were also found to result in a 4-kg/kWe savings in specific mass over SP-100/Brayton systems. The potential of advanced, higher temperature reactor and power conversion technologies for achieving reduced mass Rankine and Brayton systems was also investigated. A target goal of 5 kg/kWe specific mass was deemed reasonable given either 1400 K potassium Rankine with 1500 K lithium-cooled reactors or 2000 K gas cooled reactors with Brayton conversion.

  5. A philosophy for space nuclear systems safety

    NASA Astrophysics Data System (ADS)

    Marshall, A. C.

    The unique requirements and contraints of space nuclear systems require careful consideration in the development of a safety policy. The Nuclear Safety Policy Working Group (NSPWG) for the Space Exploration Initiative has proposed a hierarchical approach with safety policy at the top of the hierarchy. This policy allows safety requirements to be tailored to specific applications while still providing reassurance to regulators and the general public that the necessary measures have been taken to assure safe application of space nuclear systems. The safety policy used by the NSPWG is recommended for all space nuclear programs and missions.

  6. A philosophy for space nuclear systems safety

    SciTech Connect

    Marshall, A.C.

    1992-08-01

    The unique requirements and contraints of space nuclear systems require careful consideration in the development of a safety policy. The Nuclear Safety Policy Working Group (NSPWG) for the Space Exploration Initiative has proposed a hierarchical approach with safety policy at the top of the hierarchy. This policy allows safety requirements to be tailored to specific applications while still providing reassurance to regulators and the general public that the necessary measures have been taken to assure safe application of space nuclear systems. The safety policy used by the NSPWG is recommended for all space nuclear programs and missions.

  7. LRP130, a pentatricopeptide motif protein with a noncanonical RNA-binding domain, is bound in vivo to mitochondrial and nuclear RNAs.

    PubMed

    Mili, Stavroula; Piñol-Roma, Serafín

    2003-07-01

    LRP130 (also known as LRPPRC) is an RNA-binding protein that is a constituent of postsplicing nuclear RNP complexes associated with mature mRNA. It belongs to a growing family of pentatricopeptide repeat (PPR) motif-containing proteins, several of which have been implicated in organellar RNA metabolism. We show here that only a fraction of LRP130 proteins are in nuclei and are directly bound in vivo to at least some of the same RNA molecules as the nucleocytoplasmic shuttle protein hnRNP A1. The majority of LRP130 proteins are located within mitochondria, where they are directly bound to polyadenylated RNAs in vivo. In vitro, LRP130 binds preferentially to polypyrimidines. This RNA-binding activity maps to a domain in its C-terminal region that does not contain any previously described RNA-binding motifs and that contains only 2 of the 11 predicted PPR motifs. Therefore, LRP130 is a novel type of RNA-binding protein that associates with both nuclear and mitochondrial mRNAs and as such is a potential candidate for coordinating nuclear and mitochondrial gene expression. These findings provide the first identification of a mammalian protein directly bound to mitochondrial RNA in vivo and provide a possible molecular explanation for the recently described association of mutations in LRP130 with cytochrome c oxidase deficiency in humans. PMID:12832482

  8. Flight control application of new stability robustness bounds for linear uncertain systems

    NASA Technical Reports Server (NTRS)

    Yedavalli, Rama K.

    1993-01-01

    This paper addresses the issue of obtaining bounds on the real parameter perturbations of a linear state-space model for robust stability. Based on Kronecker algebra, new, easily computable sufficient bounds are derived that are much less conservative than the existing bounds since the technique is meant for only real parameter perturbations (in contrast to specializing complex variation case to real parameter case). The proposed theory is illustrated with application to several flight control examples.

  9. A search for a bound {Sigma} hypernuclei in the A = 3 system

    SciTech Connect

    Barakat, M.B.

    1992-12-31

    The search for a bound {Sigma} hypernuclei state in the A = 3, 4 systems was undertaken at the AGS using the Hypernuclear Spectrometer, `Moby Dick` and the secondary Kaon beam line, LESBII at an incident momentum of 600 MeV/c. Both liquid {sup 3}He and {sup 4}He targets were used. An analysis of the {sup 3}He(K{sup {minus}}, {pi}{sup +}) data tagged by two charged particles decay mode of the recoil system unveiled some strength in the EE (Excitation Energy) spectrum just below the {Sigma}{sup {minus}}D threshold. On the other hand, Monte Carlo simulation of the various decay modes of the formed recoil system revealed that the above strength is consistent with the formation of a {Sigma}{sup 0} nn system. A theoretical background and experimental arrangements are given in Chapters one and two; while a detailed analysis and discussion of the {sup 3}He(K{sup {minus}}, {pi}{sup +})X reaction data are presented in Chapters three and four respectively.

  10. Nuclear propulsion system options for Mars missions

    SciTech Connect

    Emrich, W.J. Jr.; Young, A.C. )

    1992-03-01

    This paper focuses on the use of a nuclear thermal rocket to accomplish a variety of space missions with emphasis on the manned Mars mission. The particle-bed-reactor type nuclear engine was chosen as the baseline engine because of its perceived versatility over other nuclear propulsion systems in conducting a wide variety of tasks. This study indicates that the particle-bed-reactor engine with its high engine thrust-to-weight ratio (about 20) and high specific impulse (about 950 to 1050 sec) offers distinct advantages over the larger and heavier NERVA-type nuclear engines.

  11. Nuclear propulsion system options for Mars missions

    NASA Technical Reports Server (NTRS)

    Emrich, William J., Jr.; Young, Archie C.

    1992-01-01

    This paper focuses on the use of a nuclear thermal rocket to accomplish a variety of space missions with emphasis on the manned Mars mission. The particle-bed-reactor type nuclear engine was chosen as the baseline engine because of its perceived versatility over other nuclear propulsion systems in conducting a wide variety of tasks. This study indicates that the particle-bed-reactor engine with its high engine thrust-to-weight ratio (about 20) and high specific impulse (about 950 to 1050 sec) offers distinct advantages over the larger and heavier NERVA-type nuclear engines.

  12. Dual mode nuclear rocket system applications.

    NASA Technical Reports Server (NTRS)

    Boretz, J. E.; Bell, J. M.; Plebuch, R. K.; Priest, C. C.

    1972-01-01

    Mission areas where the dual-mode nuclear rocket system is superior to nondual-mode systems are demonstrated. It is shown that the dual-mode system is competitive with the nondual-mode system even for those specific missions and particular payload configurations where it does not have a clear-cut advantage.

  13. Transactions of the fourth symposium on space nuclear power systems

    SciTech Connect

    El-Genk, M.S.; Hoover, M.D.

    1987-01-01

    This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these papers include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, refractory alloys and high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

  14. Transactions of the fifth symposium on space nuclear power systems

    SciTech Connect

    El-Genk, M.S.; Hoover, M.D.

    1988-01-01

    This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these paper include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

  15. Software Quality Assurance for Nuclear Safety Systems

    SciTech Connect

    Sparkman, D R; Lagdon, R

    2004-05-16

    The US Department of Energy has undertaken an initiative to improve the quality of software used to design and operate their nuclear facilities across the United States. One aspect of this initiative is to revise or create new directives and guides associated with quality practices for the safety software in its nuclear facilities. Safety software includes the safety structures, systems, and components software and firmware, support software and design and analysis software used to ensure the safety of the facility. DOE nuclear facilities are unique when compared to commercial nuclear or other industrial activities in terms of the types and quantities of hazards that must be controlled to protect workers, public and the environment. Because of these differences, DOE must develop an approach to software quality assurance that ensures appropriate risk mitigation by developing a framework of requirements that accomplishes the following goals: {sm_bullet} Ensures the software processes developed to address nuclear safety in design, operation, construction and maintenance of its facilities are safe {sm_bullet} Considers the larger system that uses the software and its impacts {sm_bullet} Ensures that the software failures do not create unsafe conditions Software designers for nuclear systems and processes must reduce risks in software applications by incorporating processes that recognize, detect, and mitigate software failure in safety related systems. It must also ensure that fail safe modes and component testing are incorporated into software design. For nuclear facilities, the consideration of risk is not necessarily sufficient to ensure safety. Systematic evaluation, independent verification and system safety analysis must be considered for software design, implementation, and operation. The software industry primarily uses risk analysis to determine the appropriate level of rigor applied to software practices. This risk-based approach distinguishes safety

  16. Nuclear power propulsion system for spacecraft

    NASA Astrophysics Data System (ADS)

    Koroteev, A. S.; Oshev, Yu. A.; Popov, S. A.; Karevsky, A. V.; Solodukhin, A. Ye.; Zakharenkov, L. E.; Semenkin, A. V.

    2015-12-01

    The proposed designs of high-power space tugs that utilize solar or nuclear energy to power an electric jet engine are reviewed. The conceptual design of a nuclear power propulsion system (NPPS) is described; its structural diagram, gas circuit, and electric diagram are discussed. The NPPS incorporates a nuclear reactor, a thermal-to-electric energy conversion system, a system for the conversion and distribution of electric energy, and an electric propulsion system. Two criterion parameters were chosen in the considered NPPS design: the temperature of gaseous working medium at the nuclear reactor outlet and the rotor speed of turboalternators. The maintenance of these parameters at a given level guarantees that the needed electric voltage is generated and allows for power mode control. The processes of startup/shutdown and increasing/reducing the power, the principles of distribution of electric energy over loads, and the probable emergencies for the proposed NPPS design are discussed.

  17. Conserved correlation in PT-symmetric systems: Scattering and bound states

    NASA Astrophysics Data System (ADS)

    Abhinav, Kumar; Jayannavar, Arun; Panigrahi, Prasanta K.

    2013-04-01

    For one-dimensional PT-symmetric systems, it is observed that the non-local product ψ∗(-x,t)ψ(x,t), obtained from the continuity equation can be interpreted as a conserved correlation function. This leads to physical conclusions regarding both discrete and continuum states of such systems. Asymptotic states are shown to have necessarily broken PT-symmetry, leading to modified scattering and transfer matrices. This yields restricted boundary conditions, e.g., incidence from both sides, analogous to that of the proposed PT CPA laser (Longhi, 2010) [4]. The interpretation of 'left' and 'right' states leads to a HermitianS-matrix, resulting in the non-conservation of the 'flux'. This further satisfies a 'duality' condition, identical to the optical analogues (Paasschens et al., 1996) [17]. However, the non-local conserved scalar implements alternate boundary conditions in terms of 'in' and 'out' states, leading to the pseudo-Hermiticity condition in terms of the scattering matrix. Interestingly, when PT-symmetry is preserved, it leads to stationary states with real energy, naturally interpretable as bound states. The broken PT-symmetric phase is also captured by this correlation, with complex-conjugate pair of energies, interpreted as resonances.

  18. Nuclear Materials Identification System Operational Manual

    SciTech Connect

    Chiang, L.G.

    2001-04-10

    This report describes the operation and setup of the Nuclear Materials Identification System (NMIS) with a {sup 252}Cf neutron source at the Oak Ridge Y-12 Plant. The components of the system are described with a description of the setup of the system along with an overview of the NMIS measurements for scanning, calibration, and confirmation of inventory items.

  19. Safe, Affordable, Nuclear Thermal Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Houts, M. G.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Doughty, G. E.

    2014-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

  20. The Nuclear Criticality Information System: An update

    SciTech Connect

    Koponen, B.L.

    1991-07-01

    The US Department of Energy`s Nuclear Criticality Information System (NCIS) has served the criticality community for the past ten years with publications and with an online information system. NCIS provides a mean for widely distributed nuclear criticality specialists to communicate and work together instantly. Users of the system may receive assistance from all members of the NCIS community, which provides a much broader base of support than is available at any single site. When unified by NCIS, these diverse specialists provide a resource that has proven to be very useful in the safe handling of fissile material. NCIS also is a source of current nuclear criticality safety information; the rapid access of such up-to-date information on the handling of fissile materials outside of nuclear reactors is international in scope, extending beyond political and geographical boundaries.

  1. The Nuclear Criticality Information System: An update

    SciTech Connect

    Koponen, B.L.

    1991-07-01

    The US Department of Energy's Nuclear Criticality Information System (NCIS) has served the criticality community for the past ten years with publications and with an online information system. NCIS provides a mean for widely distributed nuclear criticality specialists to communicate and work together instantly. Users of the system may receive assistance from all members of the NCIS community, which provides a much broader base of support than is available at any single site. When unified by NCIS, these diverse specialists provide a resource that has proven to be very useful in the safe handling of fissile material. NCIS also is a source of current nuclear criticality safety information; the rapid access of such up-to-date information on the handling of fissile materials outside of nuclear reactors is international in scope, extending beyond political and geographical boundaries.

  2. Non-Nuclear Testing of Space Nuclear Systems at NASA MSFC

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Pearson, Boise J.; Aschenbrenner, Kenneth C.; Bradley, David E.; Dickens, Ricky; Emrich, William J.; Garber, Anne; Godfroy, Thomas J.; Harper, Roger T.; Martin, Jim J.; Polzin, Kurt; Schoenfeld, Michael P.; Webster, Kenneth L.

    2010-01-01

    Highly realistic non-nuclear testing can be used to investigate and resolve potential issues with space nuclear power and propulsion systems. Non-nuclear testing is particularly useful for systems designed with fuels and materials operating within their demonstrated nuclear performance envelope. Non-nuclear testing allows thermal hydraulic, heat transfer, structural, integration, safety, operational, performance, and other potential issues to be investigated and resolved with a greater degree of flexibility and at reduced cost and schedule compared to nuclear testing. The primary limit of non-nuclear testing is that nuclear characteristics and potential nuclear issues cannot be directly investigated. However, non-nuclear testing can be used to augment the potential benefit from any nuclear testing that may be required for space nuclear system design and development. This paper describes previous and ongoing non-nuclear testing related to space nuclear systems at NASA's Marshall Space Flight Center (MSFC).

  3. Estimates of mean consequences and confidence bounds on the mean associated with low-probability seismic events in total system performance assessments

    SciTech Connect

    Pensado, Osvaldo; Mancillas, James

    2007-07-01

    An approach is described to estimate mean consequences and confidence bounds on the mean of seismic events with low probability of breaching components of the engineered barrier system. The approach is aimed at complementing total system performance assessment models used to understand consequences of scenarios leading to radionuclide releases in geologic nuclear waste repository systems. The objective is to develop an efficient approach to estimate mean consequences associated with seismic events of low probability, employing data from a performance assessment model with a modest number of Monte Carlo realizations. The derived equations and formulas were tested with results from a specific performance assessment model. The derived equations appear to be one method to estimate mean consequences without having to use a large number of realizations. (authors)

  4. A matrix lower bound

    SciTech Connect

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  5. Towards an integrated forecasting system for fisheries on habitat-bound stocks

    NASA Astrophysics Data System (ADS)

    Christensen, A.; Butenschön, M.; Gürkan, Z.; Allen, I. J.

    2013-03-01

    First results of a coupled modelling and forecasting system for fisheries on habitat-bound stocks are being presented. The system consists currently of three mathematically, fundamentally different model subsystems coupled offline: POLCOMS providing the physical environment implemented in the domain of the north-west European shelf, the SPAM model which describes sandeel stocks in the North Sea, and the third component, the SLAM model, which connects POLCOMS and SPAM by computing the physical-biological interaction. Our major experience by the coupling model subsystems is that well-defined and generic model interfaces are very important for a successful and extendable coupled model framework. The integrated approach, simulating ecosystem dynamics from physics to fish, allows for analysis of the pathways in the ecosystem to investigate the propagation of changes in the ocean climate and to quantify the impacts on the higher trophic level, in this case the sandeel population, demonstrated here on the basis of hindcast data. The coupled forecasting system is tested for some typical scientific questions appearing in spatial fish stock management and marine spatial planning, including determination of local and basin-scale maximum sustainable yield, stock connectivity and source/sink structure. Our presented simulations indicate that sandeel stocks are currently exploited close to the maximum sustainable yield, even though periodic overfishing seems to have occurred, but large uncertainty is associated with determining stock maximum sustainable yield due to stock inherent dynamics and climatic variability. Our statistical ensemble simulations indicates that the predictive horizon set by climate interannual variability is 2-6 yr, after which only an asymptotic probability distribution of stock properties, like biomass, are predictable.

  6. Physical Uncertainty Bounds (PUB)

    SciTech Connect

    Vaughan, Diane Elizabeth; Preston, Dean L.

    2015-03-19

    This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.

  7. Robust Consensus of Nonlinear Multiagent Systems With Switching Topology and Bounded Noises.

    PubMed

    Chen, Yao; Dong, Hairong; Lu, Jinhu; Sun, Xubin; Liu, Kexin

    2016-06-01

    Consensus of multiagent systems (MASs) is an intriguing topic in recent years due to its widely used application in robotics, biology, computer, and social science. In the real world, the evolution of MAS is inevitably involved in dynamical environments and the recent development of MAS calls for novel tools for the analysis of MAS with dynamic topology. In addition, the interactions between agents are generally nonlinear and environmental noises are ubiquitous in the communication channels between agents. However, the existing investigation on MAS places little attention on nonlinear models and the inner relationship between external disturbance and consensus is still unclear. Facing these problems, this paper considers an MAS in which the interactions between agents are nonlinear and the communication between agents are infected by environmental noises. By using a novel method of nonsmooth Lyapunov candidate, it has been demonstrated that such an MAS can realize robust consensus under the conditions of jointly (sequentially) connected topology and bounded noises. Finally, simulation results validate the effectiveness of these criteria. PMID:26241983

  8. Molecular Dynamics Simulations on Various Weakly Bound Water-Parahydrogen Systems at Ultracold Temperature

    NASA Astrophysics Data System (ADS)

    Schmidt, Matthew; Ing, Christopher; Constable, Stephen; Zeng, Tao; Yang, Jing; Nyman, Michael; Roy, Pierre-Nicholas

    2012-06-01

    We report path integral molecular dynamics (PIMD) studies on the low temperature properties of weakly bound clusters. We use a new version of the molecular modeling toolkit (MMTK) with an implementation of the Path Integral Langevin Equation (PILE) thermostat. We focus on the low temperature dynamics of parahydrogen clusters with a non-rotating water dopant molecule. We also extend our study to the reverse case where hydrogen is doped in a water cluster. The low temperature properties of parahydrogen clusters within water clathrates are explored. These systems are of great interest in the context of hydrogen storage. We compare our PIMD results to those of more traditional path integral Monte Carlo (PIMC) methods. We also report on an extension of the PIMD approach to zero temperature using the so-called Path Integral Ground State (PIGS) approach. The technique is analogous to diffusion Monte Carlo (DMC) but with important differences that will be presented. We discuss the merits of various trial functions and the PIGS results are benchmarked using exact calculations for small clusters.

  9. Verifying the error bound of numerical computation implemented in computer systems

    SciTech Connect

    Sawada, Jun

    2013-03-12

    A verification tool receives a finite precision definition for an approximation of an infinite precision numerical function implemented in a processor in the form of a polynomial of bounded functions. The verification tool receives a domain for verifying outputs of segments associated with the infinite precision numerical function. The verification tool splits the domain into at least two segments, wherein each segment is non-overlapping with any other segment and converts, for each segment, a polynomial of bounded functions for the segment to a simplified formula comprising a polynomial, an inequality, and a constant for a selected segment. The verification tool calculates upper bounds of the polynomial for the at least two segments, beginning with the selected segment and reports the segments that violate a bounding condition.

  10. The longevity of nuclear power systems

    SciTech Connect

    Speiwak, I.; Livingston, R.S.

    1985-08-01

    It appears likely that nuclear power plants can be operated safely in excess of the licensed 40 years. This conclusion is based on a systematic review of the plant systems and favorable experience in refurbishing old fossil plants, the Savannah River production reactors and the early British Magnox reactors. The technical areas that may present the greatest difficulty are the reactor pressure vessel, the electrical cable, and reinforced concrete structures. Utilities are also concerned about the difficulty of the Nuclear Regulatory Commission's relicensing process, which has not as yet been defined. If license extensions can be obtained, utilities can afford to spend many hundreds of millions of dollars to achieve an additional ten or more years of operation. Nuclear plant life extension has favorable implications for the long-term price of electricity in systems containing nuclear power plants.

  11. Nuclear magnetic resonance in Kondo lattice systems

    NASA Astrophysics Data System (ADS)

    Curro, Nicholas J.

    2016-06-01

    Nuclear magnetic resonance has emerged as a vital tool to explore the fundamental physics of Kondo lattice systems. Because nuclear spins experience two different hyperfine couplings to the itinerant conduction electrons and to the local f moments, the Knight shift can probe multiple types of spin correlations that are not accessible via other techniques. The Knight shift provides direct information about the onset of heavy electron coherence and the emergence of the heavy electron fluid.

  12. Decontamination of nuclear systems at the Grand Gulf Nuclear Station

    SciTech Connect

    Weed, R.D.; Baker, K.R.

    1996-12-31

    Early in 1994 Management at the Grand Gulf Nuclear Station realized that a potential decontamination of several reactor systems was needed to maintain the commitments to the {open_quotes}As Low As Reasonably Achievable{close_quotes} (ALARA) program. There was a substantial amount of planned outage work required to repair and replace some internals in loop isolation valves and there were inspections and other outage work that needed to be accomplished as it had been postponed from previous outages because of the radiation exposure levels in and around the system equipment. Management scheduled for the procurement specification to be revised to incorporate additional boundary areas which had not been previously considered. The schedule included the period for gathering bids, awarding a contract, and reviewing the contractor`s procedures and reports and granting approval for the decontamination to proceed during the upcoming outage. In addition to the reviews required by the engineering group for overall control of the process, the plant system engineers had to prepare procedures at the system level to provide for a smooth operation to be made during the decontamination of the systems. The system engineers were required to make certain that the decontamination fluids would be contained within the systems being decontaminated and that they would not cross contaminate any other system not being decontaminated. Since these nuclear stations do not have the provisions for decontaminating these systems with using additional equipment, the equipment required is furnished by the contractor as skid mounted packaged units which can be moved into the area, set up near the system being decontaminated, and after the decontamination is completed, the skid mounted packages are removed as part of the contract. Figure 1 shows a typical setup in block diagram required to perform a reactor system decontamination. 1 fig.

  13. Characteristic Features of Strangeness Nuclear Systems

    NASA Astrophysics Data System (ADS)

    Akaishi, Yoshinori

    2001-10-01

    The Λ-Σ coupling is one of the most characteristic dynamics in hypernuclear physics, since the Σ-Λ mass difference is muc h smaller than Δ-N one. The coupling can be divided into coherent and incoheren t parts. The suppression of the incoherent part solves a long-standing problem of Λ-overbinding in ^5_ΛHe but it, in turn, causes an un derbinding problem in ^4_ΛHe. This shortage is overcome by the coherent cou pling which is equivalently expressed by a ΛNN three-body force. The three-body force has a large effect exclusively on the 0^+ state of ^4_ΛHe among s-shell hypernuclei according to coherently added enhancement. The coherent coupling explains also the ^4_ΣHe spectrum recently observed at BNL. In dense neutron matter the coherent Λ-Σ coupling causes strong Σ^0 admixture of 5 ~25 % at ρ=ρ0 ~ 3ρ0 where Λ and Σ^0 components are mixed up as one particle Λ_coh. This coherent mixing drastically affects the hyperon composition of neutron-star matter. One of the most important but yet unsolved problems is how the hadron property changes in nuclear medium. In strangeness sector, this problem is connected to an exciting issue of kao n condensation. Recently Akaishi and Yamazaki predicted that nuclear barK bound sta tes possibly exist in ^3He and ^4He with large binding energies of 108 MeV and of 86 MeV and narrow widths of 20 MeV and of 34 MeV, respectively. The formation of deeply-bound barK nuclear states in He and Be gives a new means to investigate hadron properties in cold high-density nucl ear medium because barK strongly contracts the core nuclei. Observation of such barK nuclear states would provide information of fundamental importance in relation to strangeness condensation.

  14. Generation-IV Nuclear Energy Systems

    NASA Astrophysics Data System (ADS)

    McFarlane, Harold

    2008-05-01

    Nuclear power technology has evolved through roughly three generations of system designs: a first generation of prototypes and first-of-a-kind units implemented during the period 1950 to 1970; a second generation of industrial power plants built from 1970 to the turn of the century, most of which are still in operation today; and a third generation of evolutionary advanced reactors which began being built by the turn of the 20^th century, usually called Generation III or III+, which incorporate technical lessons learned through more than 12,000 reactor-years of operation. The Generation IV International Forum (GIF) is a cooperative international endeavor to develop advanced nuclear energy systems in response to the social, environmental and economic requirements of the 21^st century. Six Generation IV systems under development by GIF promise to enhance the future contribution and benefits of nuclear energy. All Generation IV systems aim at performance improvement, new applications of nuclear energy, and/or more sustainable approaches to the management of nuclear materials. High-temperature systems offer the possibility of efficient process heat applications and eventually hydrogen production. Enhanced sustainability is achieved primarily through adoption of a closed fuel cycle with reprocessing and recycling of plutonium, uranium and minor actinides using fast reactors. This approach provides significant reduction in waste generation and uranium resource requirements.

  15. Nuclear electric propulsion operational reliability and crew safety study: NEP systems/modeling report

    NASA Technical Reports Server (NTRS)

    Karns, James

    1993-01-01

    The objective of this study was to establish the initial quantitative reliability bounds for nuclear electric propulsion systems in a manned Mars mission required to ensure crew safety and mission success. Finding the reliability bounds involves balancing top-down (mission driven) requirements and bottom-up (technology driven) capabilities. In seeking this balance we hope to accomplish the following: (1) provide design insights into the achievability of the baseline design in terms of reliability requirements, given the existing technology base; (2) suggest alternative design approaches which might enhance reliability and crew safety; and (3) indicate what technology areas require significant research and development to achieve the reliability objectives.

  16. Search for φ-Meson Nuclear Bound States in the overline{p} + ^{A}Z → φ + ^{A-1}_{φ}(Z-1) Reaction

    NASA Astrophysics Data System (ADS)

    Bühler, P.; Curceanu, C.; Guaraldo, C.; Hartmann, O.; Hicks, K.; Iwasaki, M.; Ishiwatari, T.; Kienle, P.; Marton, J.; Muto, R.; Niiyama, M.; Noumi, H.; Ohnishi, H.; Okada, S.; Vidal, A.; Sakaguchi, A.; Sakuma, F.; Sawada, S.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Tsukada, K.; Tedeschi, D. J.; Doce, O.; Widmann, E.; Yokkaichi, S.; Zmeskal, J.; J-Parc P29 Collaboration

    We propose to study in-medium mass modification of the φ mesonusing the formation of φ meson bound state. We demonstrate that a clear missing-mass spectrum can be obtained efficiently by (overline{p}, φ) spectroscopy together with the Λ tagging, using the primary reaction channel overline{p} p → φ φ. A systematic study over several nuclear targets will yield a unique, definitive and precise determination of the in-medium mass modification of the vector meson φ (s overline{s}).

  17. Intelligent Automated Nuclear Fuel Pellet Inspection System

    SciTech Connect

    S. Keyvan

    1999-11-01

    At the present time, nuclear pellet inspection is performed manually using naked eyes for judgment and decisionmaking on accepting or rejecting pellets. This current practice of pellet inspection is tedious and subject to inconsistencies and error. Furthermore, unnecessary re-fabrication of pellets is costly and the presence of low quality pellets in a fuel assembly is unacceptable. To improve the quality control in nuclear fuel fabrication plants, an automated pellet inspection system based on advanced techniques is needed. Such a system addresses the following concerns of the current manual inspection method: (1) the reliability of inspection due to typical human errors, (2) radiation exposure to the workers, and (3) speed of inspection and its economical impact. The goal of this research is to develop an automated nuclear fuel pellet inspection system which is based on pellet video (photographic) images and uses artificial intelligence techniques.

  18. Review of Nuclear Thermal Propulsion Systems

    NASA Astrophysics Data System (ADS)

    Gabrielli, Roland Antonius; Herdrich, Georg

    2015-11-01

    This article offers a summary of past efforts in the development of Nuclear Thermal Propulsion systems for space transportation. First, the generic principle of thermal propulsion is outlined: a propellant is directly heated by a power source prior to being expanded which creates a thrusting force on the rocket. This enables deriving a motivation for the use of Nuclear Thermal Propulsion (NTP) relying on nuclear power sources. Then, a summary of major families of NTP systems is established on the basis of a literature survey. These families are distinguished by the nature of their power source, the most important being systems with radioisotope, fission, and fusion cores. Concepts proposing to harness the annihilation of matter and anti-matter are only touched briefly due to their limited maturity. For each family, an overview of physical fundamentals, technical concepts, and - if available - tested engines' propulsion parameters is given.

  19. Quantum Transport through a Triple Quantum Dot System in the Presence of Majorana Bound States

    NASA Astrophysics Data System (ADS)

    Jiang, Zhao-Tan; Cao, Zhi-Yuan; Zhong, Cheng-Cheng

    2016-05-01

    We study the electron transport through a special quantum-dot (QD) structure composed of three QDs and two Majorana bound states (MBSs) using the nonequilibrium Green's function technique. This QD-MBS ring structure includes two channels with the two coupled MBSs being Channel 1 and one QD being Channel 2, and three types of transport processes such as the electron transmission (ET), the Andreev reflection (AR), and the crossed Andreev reflection (CAR). By comparing the ET, AR, and CAR processes through Channels 1 and 2, we make a systematic study on the transport properties of the QD-MBS ring. It is shown that there appear two kinds of characteristic transport patterns for Channels 1 and 2, as well as the interplay between the two patterns. Of particular interest is that there exists an AR-assisted ET process in Channel 2, which is different from that in Channel 1. Thus a clear “X” pattern due to the ET and AR processes appears in the ET, AR, and CAR transmission coefficients. Moreover, we study how Channel 2 affects the three transport processes when Channel 1 is tuned in the ET and CAR regimes. It is shown that the transport properties of the ET, AR and CAR processes can be adjusted by tuning the energy level of the QD embedded in Channel 2. We believe this research should be a helpful reference for understanding the transport properties in the QD-MBS coupled systems. Supported by National Natural Science Foundation of China under Grant No. 11274040, and by the Program for New Century Excellent Talents in University under Grant No. NCET-08-0044

  20. Review of Current Nuclear Vacuum System Technologies

    SciTech Connect

    Carroll, M.; McCracken, J.; Shope, T.

    2003-02-25

    Nearly all industrial operations generate unwanted dust, particulate matter, and/or liquid wastes. Waste dust and particulates can be readily tracked to other work locations, and airborne particulates can be spread through ventilation systems to all locations within a building, and even vented outside the building - a serious concern for processes involving hazardous, radioactive, or nuclear materials. Several varieties of vacuum systems have been proposed and/or are commercially available for clean up of both solid and liquid hazardous and nuclear materials. A review of current technologies highlights both the advantages and disadvantages of the various systems, and demonstrates the need for a system designed to address issues specific to hazardous and nuclear material cleanup. A review of previous and current hazardous/nuclear material cleanup technologies is presented. From simple conventional vacuums modified for use in industrial operations, to systems specifically engineered for such purposes, the advantages and disadvantages are examined in light of the following criteria: minimal worker exposure; minimal secondary waste generation;reduced equipment maintenance and consumable parts; simplicity of design, yet fully compatible with all waste types; and ease of use. The work effort reviews past, existing and proposed technologies in light of such considerations. Accomplishments of selected systems are presented, including identified areas where technological improvements could be suggested.

  1. Decentralised robust stabilisation of uncertain large-scale interconnected time-delay systems with unknown upper bounds of uncertainties

    NASA Astrophysics Data System (ADS)

    Wu, Hansheng

    2016-09-01

    The problem of decentralised robust stabilisation is considered for a class of uncertain large-scale time-delay interconnected dynamical systems. In the paper, the upper bounds of delayed state perturbations, uncertainties, interconnection terms, and external disturbances are assumed to be completely unknown, and the delays are assumed to be any non-negative constants. For such a class of uncertain large-scale time-delay interconnected systems, a new method is presented whereby a class of adaptation-free decentralised local robust state feedback controllers can be constructed. In addition, it is also shown that the solutions of uncertain large-scale time-delay interconnected systems can be guaranteed to be uniformly ultimately bounded. Finally, as an application to the practical mechanical systems, some simulations of a numerical example are provided to demonstrate the validity of the theoretical results.

  2. 21 CFR 892.1310 - Nuclear tomography system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear tomography system. 892.1310 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1310 Nuclear tomography system. (a) Identification. A nuclear tomography system is a device intended to detect nuclear radiation in the body...

  3. 21 CFR 892.1310 - Nuclear tomography system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear tomography system. 892.1310 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1310 Nuclear tomography system. (a) Identification. A nuclear tomography system is a device intended to detect nuclear radiation in the body...

  4. Performance Criteria of Nuclear Space Propulsion Systems

    NASA Astrophysics Data System (ADS)

    Shepherd, L. R.

    Future exploration of the solar system on a major scale will require propulsion systems capable of performance far greater than is achievable with the present generation of rocket engines using chemical propellants. Viable missions going deeper into interstellar space will be even more demanding. Propulsion systems based on nuclear energy sources, fission or (eventually) fusion offer the best prospect for meeting the requirements. The most obvious gain coming from the application of nuclear reactions is the possibility, at least in principle, of obtaining specific impulses a thousandfold greater than can be achieved in chemically energised rockets. However, practical considerations preclude the possibility of exploiting the full potential of nuclear energy sources in any engines conceivable in terms of presently known technology. Achievable propulsive power is a particularly limiting factor, since this determines the acceleration that may be obtained. Conventional chemical rocket engines have specific propulsive powers (power per unit engine mass) in the order of gigawatts per tonne. One cannot envisage the possibility of approaching such a level of performance by orders of magnitude in presently conceivable nuclear propulsive systems. The time taken, under power, to reach a given terminal velocity is proportional to the square of the engine's exhaust velocity and the inverse of its specific power. An assessment of various nuclear propulsion concepts suggests that, even with the most optimistic assumptions, it could take many hundreds of years to attain the velocities necessary to reach the nearest stars. Exploration within a range of the order of a thousand AU, however, would appear to offer viable prospects, even with the low levels of specific power of presently conceivable nuclear engines.

  5. Uniform Regularity and Vanishing Dissipation Limit for the Full Compressible Navier-Stokes System in Three Dimensional Bounded Domain

    NASA Astrophysics Data System (ADS)

    Wang, Yong

    2016-09-01

    In the present paper, we study the uniform regularity and vanishing dissipation limit for the full compressible Navier-Stokes system whose viscosity and heat conductivity are allowed to vanish at different orders. The problem is studied in a three dimensional bounded domain with Navier-slip type boundary conditions. It is shown that there exists a unique strong solution to the full compressible Navier-Stokes system with the boundary conditions in a finite time interval which is independent of the viscosity and heat conductivity. The solution is uniformly bounded in {W^{1,infty}} and is a conormal Sobolev space. Based on such uniform estimates, we prove the convergence of the solutions of the full compressible Navier-Stokes to the corresponding solutions of the full compressible Euler system in {L^infty(0,T; L^2)}, {L^infty(0,T; H1)} and {L^infty([0,T]×Ω)} with a rate of convergence.

  6. Role of the continuum in reactions with weakly bound systems: A comparative study between the time evolution of a break-up wave function and its coupled-channel approximation

    SciTech Connect

    Dasso, C. H.; Vitturi, A.

    2009-06-15

    We exploit a model describing the breakup of weakly bound nuclei that can be used as a laboratory for testing different prescriptions that have been advanced in the literature to take into account the nearby presence of continuum states. In the model, we follow the evolution of a single-particle wave function in one dimension, initially bound by a Woods-Saxon type potential and then perturbed by a time- and position-dependent external field. Proper choices of this potential can simulate the effect of the interaction between reaction partners in a nuclear collision. These processes generate inelastic excitation probabilities that--distributed over the bound and continuum states of the system--lead to either a partial or a total fragmentation of the final wave function.

  7. Bounding the Role of Black Carbon in the Climate System: A Scientific Assessment

    SciTech Connect

    Bond, Tami C.; Doherty, Sarah J.; Fahey, D. W.; Forster, Piers; Berntsen, T.; DeAngelo, B. J.; Flanner, M. G.; Ghan, Steven J.; Karcher, B.; Koch, Dorothy; Kinne, Stefan; Kondo, Yutaka; Quinn, P. K.; Sarofim, Marcus; Schultz, Martin; Schulz, M.; Venkataraman, C.; Zhang, Hua; Zhang, Shiqiu; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, Joshua P.; Shindell, Drew; Storelvmo, Trude; Warren, Stephen G.; Zender, C. S.

    2013-06-06

    Black carbon aerosol plays a unique and important role in Earth’s climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. Predominant sources are combustion related; namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr-1 in the year 2000 with an uncertainty range of 2000 to 29000. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption, influence on liquid, mixed-phase, and ice clouds, and deposition on snow and ice. These effects are calculated with models, but when possible, they are evaluated with both microphysical measurements and field observations. Global atmospheric absorption attributable to black carbon is too low in many models, and should be increased by about about 60%. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of black carbon is +0.43 W m-2 with 90% uncertainty bounds of (+0.17, +0.68) W m-2. Total direct forcing by all black carbon sources in the present day is estimated as +0.49 (+0.20, +0.76) W m-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings and their rapid responses and feedbacks. The best estimate of industrial-era (1750 to 2005) climate forcing of black carbon through all forcing mechanisms is +0.77 W m-2 with 90% uncertainty bounds of +-0.06 to +1.53 W m-2. Thus, there is a 96% probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. With a value of +0.77 W m-2, black carbon is likely the second

  8. Bounding the role of black carbon in the climate system: A scientific assessment

    NASA Astrophysics Data System (ADS)

    Bond, T. C.; Doherty, S. J.; Fahey, D. W.; Forster, P. M.; Berntsen, T.; Deangelo, B. J.; Flanner, M. G.; Ghan, S.; KäRcher, B.; Koch, D.; Kinne, S.; Kondo, Y.; Quinn, P. K.; Sarofim, M. C.; Schultz, M. G.; Schulz, M.; Venkataraman, C.; Zhang, H.; Zhang, S.; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, J. P.; Shindell, D.; Storelvmo, T.; Warren, S. G.; Zender, C. S.

    2013-06-01

    carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr-1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m-2 with 90% uncertainty bounds of (+0.08, +1.27) W m-2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m-2 with 90% uncertainty bounds of +0.17 to +2.1 W m-2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm

  9. Bounding the Role of Black Carbon in the Climate System: a Scientific Assessment

    NASA Technical Reports Server (NTRS)

    Bond, T. C.; Doherty, S. J.; Fahey, D. W.; Forster, P. M.; Bernsten, T.; DeAngelo, B. J.; Flanner, M. G.; Ghan, S.; Karcher, B.; Koch, D.; Kinne, S.; Kondo, Y.; Quinn, P. K.; Sarofim, M. C.; Schultz, M. G.; Schulz, M.; Venkataraman, C.; Zhang, H.; Zhang, S.; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, J. P.; Shindell, D.; Storelvmo, T.; Warren, S. G.; Zender, C. S.

    2013-01-01

    Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg/yr in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W/sq m with 90% uncertainty bounds of (+0.08, +1.27)W/sq m. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W/sq m. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W/sq m with 90% uncertainty bounds of +0.17 to +2.1 W/sq m. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing

  10. Orphan nuclear receptor Errγ induces C-reactive protein gene expression through induction of ER-bound Bzip transmembrane transcription factor CREBH.

    PubMed

    Misra, Jagannath; Chanda, Dipanjan; Kim, Don-Kyu; Cho, Seung-Rye; Koo, Seung-Hoi; Lee, Chul-Ho; Back, Sung Hoon; Choi, Hueng-Sik

    2014-01-01

    The orphan nuclear receptor estrogen-related receptor-γ (ERRγ) is a constitutively active transcription factor regulating genes involved in several important cellular processes, including hepatic glucose metabolism, alcohol metabolism, and the endoplasmic reticulum (ER) stress response. cAMP responsive element-binding protein H (CREBH) is an ER-bound bZIP family transcription factor that is activated upon ER stress and regulates genes encoding acute-phase proteins whose expression is increased in response to inflammation. Here, we report that ERRγ directly regulates CREBH gene expression in response to ER stress. ERRγ bound to the ERRγ response element (ERRE) in the CREBH promoter. Overexpression of ERRγ by adenovirus significantly increased expression of CREBH as well as C-reactive protein (CRP), whereas either knockdown of ERRγ or inhibition of ERRγ by ERRγ specific inverse agonist, GSK5182, substantially inhibited ER stress-mediated induction of CREBH and CRP. The transcriptional coactivator PGC1α was required for ERRγ mediated induction of the CREBH gene as demonstrated by the chromatin immunoprecipitation (ChIP) assay showing binding of both ERRγ and PGC1α on the CREBH promoter. The ChIP assay also revealed that histone H3 and H4 acetylation occurred at the ERRγ and PGC1α binding site. Moreover, chronic alcoholic hepatosteatosis, as well as the diabetic obese condition significantly increased CRP gene expression, and this increase was significantly attenuated by GSK5182 treatment. We suggest that orphan nuclear receptor ERRγ directly regulates the ER-bound transcription factor CREBH in response to ER stress and other metabolic conditions. PMID:24466039

  11. Orphan Nuclear Receptor Errγ Induces C-Reactive Protein Gene Expression through Induction of ER-Bound Bzip Transmembrane Transcription Factor CREBH

    PubMed Central

    Misra, Jagannath; Chanda, Dipanjan; Kim, Don-Kyu; Cho, Seung-Rye; Koo, Seung-Hoi; Lee, Chul-Ho; Back, Sung Hoon; Choi, Hueng-Sik

    2014-01-01

    The orphan nuclear receptor estrogen-related receptor-γ (ERRγ) is a constitutively active transcription factor regulating genes involved in several important cellular processes, including hepatic glucose metabolism, alcohol metabolism, and the endoplasmic reticulum (ER) stress response. cAMP responsive element-binding protein H (CREBH) is an ER-bound bZIP family transcription factor that is activated upon ER stress and regulates genes encoding acute-phase proteins whose expression is increased in response to inflammation. Here, we report that ERRγ directly regulates CREBH gene expression in response to ER stress. ERRγ bound to the ERRγ response element (ERRE) in the CREBH promoter. Overexpression of ERRγ by adenovirus significantly increased expression of CREBH as well as C-reactive protein (CRP), whereas either knockdown of ERRγ or inhibition of ERRγ by ERRγ specific inverse agonist, GSK5182, substantially inhibited ER stress-mediated induction of CREBH and CRP. The transcriptional coactivator PGC1α was required for ERRγ mediated induction of the CREBH gene as demonstrated by the chromatin immunoprecipitation (ChIP) assay showing binding of both ERRγ and PGC1α on the CREBH promoter. The ChIP assay also revealed that histone H3 and H4 acetylation occurred at the ERRγ and PGC1α binding site. Moreover, chronic alcoholic hepatosteatosis, as well as the diabetic obese condition significantly increased CRP gene expression, and this increase was significantly attenuated by GSK5182 treatment. We suggest that orphan nuclear receptor ERRγ directly regulates the ER-bound transcription factor CREBH in response to ER stress and other metabolic conditions. PMID:24466039

  12. Space nuclear system expansion joints

    NASA Technical Reports Server (NTRS)

    Whitaker, W. D.; Shimazki, T. T.

    1973-01-01

    The engineering, design, and fabrication status of the expansion joint unit (EJU) to be employed in the NaK primary coolant piping loop of the 5-kwe Reactor thermoelectric system are described. Four EJU's are needed in the NaK primary coolant piping loop. The four EJU's which will be identical, utilize bellows as the flexing member, are hermetically sealed, and provide double containment. The bellows are of a nested-formed design, and are to be constructed of 1-ply thickness of 0.010-in. Inconel 718. The EJU's provide a minimum piping load margin of safety of +0.22.

  13. Nuclear Technology Series. Course 5: Introduction to Nuclear Systems.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  14. Nuclear Technology Series. Course 24: Nuclear Systems and Safety.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  15. Decentralized nuclear materials management system at SNLA

    SciTech Connect

    James, R.M.

    1981-01-01

    This paper discusses the approach that Sandia took in deciding to implement a nuclear material control and accountability system on a stand-alone minicomputer despite the existence of a Univac 1108 and Univac 1100/82 centralized facility. The benefits which have been obtained by the decentralization and future applications are discussed.

  16. TOPAZ-2 Nuclear Power System safety assurance

    SciTech Connect

    Nikitin, V.P.; Ogloblin, B.G.; Lutov, Y.I.; Luppov, A.N.; Shalaev, A.I. ); Ponomarev-Stepnoi, N.N.; Usov, V.A.; Nechaev, Y.A. )

    1993-01-15

    TOPAZ-2 Nuclear Power System (NPS) safety philosophy is based on the requirement that the reactor shall not be critical during all kinds of operations prior to its start-up on the safe orbit (except for physical start-up). Potentially dangerous operation were analyzed and both computational and experimental studies were carried out.

  17. Bound states and the Bekenstein bound

    SciTech Connect

    Bousso, Raphael

    2003-10-16

    We explore the validity of the generalized Bekenstein bound, S<= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width alpha. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, however, finite-size effects contribute additional energy. We study two different models for estimating such contributions. Our analysis suggests that the bound is both valid and nontrivial if interactions are properly included, so that the entropy S counts the bound states of interacting fields.

  18. Analysis of fusion dynamics of colliding systems involving stable, loosely bound and halo nuclei

    NASA Astrophysics Data System (ADS)

    Singh Gautam, Manjeet

    2015-12-01

    This article analyzed the fusion dynamics of stable nuclei, loosely bound nuclei and halo nuclei within the view of coupled channel approach and the energy dependent Woods-Saxon potential model (EDWSP model). The different projectiles ({}3{}{6,7}{{L}}{{i}} and {}8{}{16,17}{{O}}) are bombarded onto common spherical target isotope ({}62{}144{{S}}{{m}}) wherein target isotope exhibits inelastic surface excitations as dominant mode of coupling. The fusion dynamics of {}8{}{16,17}{{O}}+{}62{}144{{S}}{{m}} reactions, wherein there is no signature of fusion suppression at above barrier energies, are adequately explained by both theoretical approaches in domain of Coulomb barrier. In case of {}3{}{6,7}{{L}}{{i}}+{}62{}144{{S}}{{m}} reactions, the couplings of inelastic surface excitations of colliding systems remove the discrepancies between below barrier fusion data and expectations of one-dimensional barrier penetration model. However, at above barrier energies, the fusion excitation function data are suppressed in comparison to the theoretical predictions of both approaches. Interestingly, this suppression of above barrier fusion data is minimized by the present model calculation by a factor of 7% with respect to a value reported in literature. Within the view of the EDWSP model calculations, the above barrier fusion data of {}3{}6{{L}}{{i}}+{}62{}144{{S}}{{m}} reaction are hindered by a factor of 25% and by a factor of 17% for {}3{}7{{L}}{{i}}+{}62{}144{{S}}{{m}} reaction which is smaller than a value as pointed out in literature. The observed sub-barrier fusion dynamics of {}3{}{6,7}{{L}}{{i}}+{}62{}144{{S}}{{m}} and {}8{}{16,17}{{O}}+{}62{}144{{S}}{{m}} reactions are reasonably described by the coupled channel model and the EDWSP model. Furthermore, the applicability of the EDWSP model has been tested for exploration of the fusion of {}2{}6{{H}}{{e}}-{{induced}} reaction and hence due to barrier modification effects, the EDWSP model successfully explains the observed

  19. Integrated nuclear data utilisation system for innovative reactors.

    PubMed

    Yamano, N; Hasegawa, A; Kato, K; Igashira, M

    2005-01-01

    A five-year research and development project on an integrated nuclear data utilisation system was initiated in 2002, for developing innovative nuclear energy systems such as accelerator-driven systems. The integrated nuclear data utilisation system will be constructed as a modular code system, which consists of two sub-systems: the nuclear data search and plotting sub-system, and the nuclear data processing and utilisation sub-system. The system will be operated with a graphical user interface in order to enable easy utilisation through the Internet by both nuclear design engineers and nuclear data evaluators. This paper presents an overview of the integrated nuclear data utilisation system, describes the development of a prototype system to examine the operability of the user interface and discusses specifications of the two sub-systems. PMID:16381697

  20. Liquid metal cooled nuclear reactor plant system

    DOEpatents

    Hunsbedt, Anstein; Boardman, Charles E.

    1993-01-01

    A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting for fuel decay during reactor shutdown, or heat produced during a mishap. The reactor system is enhanced with sealing means for excluding external air from contact with the liquid metal coolant leaking from the reactor vessel during an accident. The invention also includes a silo structure which resists attack by leaking liquid metal coolant, and an added unique cooling means.

  1. The international nuclear non-proliferation system

    SciTech Connect

    Simpson, J.; McGrew, T.

    1985-01-01

    This volume focuses upon the issues raised at this Conference, and attempts to address the international diplomatic, political and trading, rather than technical, questions which surround nuclear non-proliferation policies. It does so by bringing together chapters contributed by participants in non-proliferation diplomacy, those with experience in shaping International Atomic Energy Agency and national policies and academic observers of non-proliferation activities and the international nuclear industry. An analysis is provided of past non-proliferation policies and activities and current issues, and an attempt is made to offer ideas for new initiatives which may sustain the non-proliferation system in the future.

  2. Adaptive dynamic programming for finite-horizon optimal control of discrete-time nonlinear systems with ε-error bound.

    PubMed

    Wang, Fei-Yue; Jin, Ning; Liu, Derong; Wei, Qinglai

    2011-01-01

    In this paper, we study the finite-horizon optimal control problem for discrete-time nonlinear systems using the adaptive dynamic programming (ADP) approach. The idea is to use an iterative ADP algorithm to obtain the optimal control law which makes the performance index function close to the greatest lower bound of all performance indices within an ε-error bound. The optimal number of control steps can also be obtained by the proposed ADP algorithms. A convergence analysis of the proposed ADP algorithms in terms of performance index function and control policy is made. In order to facilitate the implementation of the iterative ADP algorithms, neural networks are used for approximating the performance index function, computing the optimal control policy, and modeling the nonlinear system. Finally, two simulation examples are employed to illustrate the applicability of the proposed method. PMID:20876014

  3. NADS — Nuclear and Atomic Data System

    NASA Astrophysics Data System (ADS)

    McKinley, Michael S.; Beck, Bret; McNabb, Dennis

    2005-05-01

    We have developed NADS (Nuclear and Atomic Data System), a web-based graphical interface for viewing pointwise and grouped cross sections and distributions. Our implementation is a client / server model. The client is a Java applet that displays the graphical interface, which has interactive 2-D, 3-D, and 4-D plots and tables. The server, which can serve and perform computations of the data, has been implemented in Python using the FUDGE package developed by Bret Beck at LLNL. Computational capabilities include algebraic manipulation of nuclear evaluated data in databases such as LLNL's ENDL-99, ENDF/B-V, and ENDF/B-VI, as well as user data. Processed data used in LLNL's transport codes are accessible as well. NADS is available from http://nuclear.llnl.gov/.

  4. NADS - Nuclear And Atomic Data System

    SciTech Connect

    McKinley, M S; Beck, B; McNabb, D

    2004-09-17

    We have developed NADS (Nuclear and Atomic Data System), a web-based graphical interface for viewing pointwise and grouped cross-sections and distributions. Our implementation is a client / server model. The client is a Java applet that displays the graphical interface, which has interactive 2-D, 3-D, and 4-D plots and tables. The server, which can serve and perform computations the data, has been implemented in Python using the FUDGE package developed by Bret Beck at LLNL. Computational capabilities include algebraic manipulation of nuclear evaluated data in databases such as LLNL's ENDL-99, ENDF/B-V and ENDF/B-VI as well as user data. Processed data used in LLNL's transport codes are accessible as well. NADS is available from http://nuclear.llnl.gov/

  5. Non-denaturing gel electrophoresis system for the purification of membrane bound proteins

    SciTech Connect

    Cavinato, A.G.; Macleod, R.M.; Ahmed, M.S.

    1988-01-01

    A new method is described for the purification of a membrane bound glycoprotein, the kappa opioid receptor from human placental tissue. The method uses preparative slab-gel electrophoresis in the presence of the non-denaturing detergent CHAPS. A linear relationship between log molecular weight and SDS PAGE electrophoretic mobility of known molecular weight markers, in the presence of CHAPS, is observed. Using this method, we were able partially to purify an /sup 3/H-etorphine binding glycoprotein, from placental villus tissue, with an apparent molecular weight range of 60-70,000. The iodinated glycoprotein migrates in SDS PAGE with an apparent molecular weight of 63,000. This method may be useful for the isolation of membrane bound proteins, especially when an affinity ligand is not available.

  6. The identification and nature of bound exciton I-line PL systems in ZnO

    SciTech Connect

    Johnston, K.; Cullen, J.; Henry, M. O.; McGlynn, Enda; Khawaga, Rehab I.

    2013-12-04

    The chemical identification of donor bound excitons in ZnO has been studied using radioactive ions. Implantations of {sup 117}Ag - which decays to radioactive Cd and In - have enabled the identification of the I{sub 2} optical feature as being the ionized donor counterpart of I{sub 9}, one of the most prominent optical features in the photoluminescence spectrum of ZnO. Both of these lines are consistent with In occupying a Zn site.

  7. The identification and nature of bound exciton I-line PL systems in ZnO

    NASA Astrophysics Data System (ADS)

    Johnston, K.; Cullen, J.; Henry, M. O.; McGlynn, Enda; Khawaga, Rehab I.

    2013-12-01

    The chemical identification of donor bound excitons in ZnO has been studied using radioactive ions. Implantations of 117Ag - which decays to radioactive Cd and In - have enabled the identification of the I2 optical feature as being the ionized donor counterpart of I9, one of the most prominent optical features in the photoluminescence spectrum of ZnO. Both of these lines are consistent with In occupying a Zn site.

  8. Nuclear Hybrid Energy Systems: Challenges and Opportunities

    SciTech Connect

    P. Sabharwall; S.B. Sitton; S.J. Yoon; C. Stoots

    2014-07-01

    With growing demand of energy and costs of the fossil fuels, coupled with the environmental concerns have resulted in an increased interest in alternative energy sources. Nuclear hybrid energy systems (NHES) are being considered which incorporates renewable energy sources such as solar and wind energy combined with nuclear reactor and energy storage to meet the peak hours demand imposed on the grid, along with providing process heat for other potential industrial applications. This concept could potentially satisfy various energy demands and improve reliability, robustness and resilience for the entire system as a whole, along with economic and net efficiency gains. This paper provides a brief understanding of potential NHES system and architecture along with the challenges

  9. Preparation of a squaraine-bounded cellulose derivative for photocurrent generation system.

    PubMed

    Saito, Yasuko; Kamitakahara, Hiroshi; Takano, Toshiyuki

    2016-02-01

    A regio-selectively squaraine (SQ)-bounded cellulose derivative (4) with a degree of substitution of SQ (DSSQ) of 0.55 was prepared from 6-O-(4-methoxytrityl) cellulose (1) by three reaction steps in 77% total yield. Lauryl SQ carboxylate (8) was also prepared as a reference sample. The photostability of SQ moieties of compound 4 in CHCl3 was not improved when compared with SQ-COOH (7), but that of SQ moiety of compound 8 was improved unexpectedly. The Langmuir-Blodgett monolayer films 4B and 8B on an indium tin oxide (ITO) electrode were successfully prepared from compounds 4 and 8 by a vertical dipping method, respectively. The films 4B and 8B showed photocurrent generation performances in the region of 550-680 nm. The quantum yield at 650 nm of film 4B was higher than that of film 8B. These results showed that the cellulose backbone of compound 4 acts as an effective scaffold for the good photocurrent generation performances and that compound 4 was a promising complementary material of the porphyrin-bounded cellulose derivatives (for photocurrent generation at 400-420 nm) for effective utilization of solar light, as well as the phthalocyanine-bounded cellulose derivatives (for photocurrent generation at 650-720 nm). PMID:26774877

  10. Alarm system for a nuclear control complex

    DOEpatents

    Scarola, Kenneth; Jamison, David S.; Manazir, Richard M.; Rescorl, Robert L.; Harmon, Daryl L.

    1994-01-01

    An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually. The integrated process status board (24) is at the apex of an information hierarchy that extends through four levels and provides access at each panel to the full display hierarchy. The control room panels are preferably of a modular construction, permitting the definition of inputs and outputs, the man machine interface, and the plant specific algorithms, to proceed in parallel with the fabrication of the panels, the installation of the equipment and the generic testing thereof.

  11. H∞ control for discrete-time singular Markovian jump systems based on the novel bounded real lemma

    NASA Astrophysics Data System (ADS)

    Wang, Jianhua; Zhang, Qingling; Liu, Xiaoxu

    2015-01-01

    This paper considers the H∞ control problem for the discrete-time singular Markovian jump systems with partially unknown transition probabilities. First, a new formulation of the bounded real lemma (BRL) for discrete-time singular Markovian jump systems is given by referencing slack variables technique, which ensures the considered systems to be regular, causal and stochastically stable with given H∞ performance index γ. Then, based on this new BRL, the desired controller gains are also presented by solving a set of strict linear matrix inequalities. A numerical example is provided to show the effectiveness and less conservativeness of the proposed methods.

  12. SP-100 space nuclear power system

    NASA Technical Reports Server (NTRS)

    Given, R. W.; Morgan, R. E.; Chi, J. W. H.

    1984-01-01

    A baseline design concept for a 100 kWe nuclear reactor space power system is described. The concept was developed under contract from JPL as part of a joint program of the DOE, DOD, and NASA. The major technical and safety constraints influencing the selection of reactor operating parameters are discussed. A lithium-cooled compact fast reactor was selected as the best candidate system. The material selected for the thermoelectric conversion system was silicon germanium (SiGe) with gallium phosphide doping. Attention is given to the improved safety of the seven in-core control rod configuration.

  13. Dry Transfer Systems for Used Nuclear Fuel

    SciTech Connect

    Brett W. Carlsen; Michaele BradyRaap

    2012-05-01

    The potential need for a dry transfer system (DTS) to enable retrieval of used nuclear fuel (UNF) for inspection or repackaging will increase as the duration and quantity of fuel in dry storage increases. This report explores the uses for a DTS, identifies associated general functional requirements, and reviews existing and proposed systems that currently perform dry fuel transfers. The focus of this paper is on the need for a DTS to enable transfer of bare fuel assemblies. Dry transfer systems for UNF canisters are currently available and in use for transferring loaded canisters between the drying station and storage and transportation casks.

  14. Fully nonlinear interfacial waves in a bounded two-fluid system

    NASA Astrophysics Data System (ADS)

    Barannyk, Lyudmyla Leonidivna

    We study the nonlinear flow which results when two immiscible inviscid incompressible fluids of different densities and separated by an interface which is free to move and which supports surface tension, are caused to flow in a straight infinite channel. Gravity is taken into consideration and the velocities of each phase can be different, thus giving rise to the Kelvin-Helmholtz instability. Our objective is to study the competing effects of the Kelvin-Helmholtz instability coupled with a stably or unstably stratified fluid system (Rayleigh-Taylor instability) when surface tension is present to regularize the dynamics. Our approach involves the derivation of two- and three-dimensional model evolution equations using long-wave asymptotics and the ensuing analysis and computation of these models. In addition, we derive the appropriate Birkhoff-Rott integro-differential equation for two-phase inviscid flows in channels of arbitrary aspect ratios. A long wave asymptotic analysis is undertaken to develop a theory for fully nonlinear interfacial waves allowing amplitudes as large as the channel thickness. The result is a set of evolution equations for the interfacial shape and the velocity jump across the interface. Linear stability analysis reveals that capillary forces stabilize short-wave disturbances in a dispersive manner and we study their effect on the fully nonlinear dynamics described by our models. In the case of two-dimensional interfacial deflections, traveling waves of permanent form are constructed and it is shown that solitary waves are possible for a range of physical parameters. All solitary waves are expressed implicitly in terms of incomplete elliptic integrals of the third kind. When the upper layer has zero density, two explicit solitary-wave solutions have been found whose amplitudes are equal to h/4 or h/9 where 2h is the channel thickness. In the absence of gravity, solitary waves are not possible but periodic ones are. Numerically constructed

  15. Photoproduction of Structure in the dπ System Near the NΔ mass: Sign of a Quasi-Bound State?

    NASA Astrophysics Data System (ADS)

    Schumacher, Reinhard

    2015-04-01

    Results from nucleon-nucleon and pion-deuteron scattering analysis show attractive resonance-like behavior in certain partial waves. But evidence for clear-cut baryon-baryon (quasi-) bound states other than the deuteron remains lacking, despite theoretical expectations that they can exist. In recent years some measurements using pd scattering have interpreted a broad bump in the dππ invariant mass distribution in terms of a ΔΔ dibaryonic resonance. If such a quasi-bound state exists, then one supposes that an NΔ quasi-bound state exists also, as supported by recent Fadeev-model calculations of the πNN system. Here we discuss ongoing work looking at the γd --> dπ+π- reaction using the CLAS detector at Jefferson Lab. A Dalitz-plot analysis shows structure in the invariant mass distributions in (dπ) + + and (dπ) 0 systems. Both are near the center of the NΔ mass distribution. Possible interpretations of this observation will be discussed. (for the CLAS Collaboration).

  16. Stochastic bounded consensus tracking of leader—follower multi-agent systems with measurement noises and sampled-data

    NASA Astrophysics Data System (ADS)

    Wu, Zhi-Hai; Peng, Li; Xie, Lin-Bo; Wen, Ji-Wei

    2012-12-01

    This paper is concerned with the stochastic bounded consensus tracking problems of leader—follower multi-agent systems, where the control input of an agent can only use the information measured at the sampling instants from its neighbours or the virtual leader with a time-varying reference state, and the measurements are corrupted by random noises. The probability limit theory and the algebra graph theory are employed to derive the necessary and sufficient conditions guaranteeing the mean square bounded consensus tracking. It is shown that the maximum allowable upper boundary of the sampling period simultaneously depends on the constant feedback gains and the network topology. Furthermore, the effects of the sampling period on the tracking performance are analysed. It turns out that from the view point of the sampling period, there is a trade-off between the tracking speed and the static tracking error. Simulations are provided to demonstrate the effectiveness of the theoretical results.

  17. Robust model predictive control of nonlinear systems with unmodeled dynamics and bounded uncertainties based on neural networks.

    PubMed

    Yan, Zheng; Wang, Jun

    2014-03-01

    This paper presents a neural network approach to robust model predictive control (MPC) for constrained discrete-time nonlinear systems with unmodeled dynamics affected by bounded uncertainties. The exact nonlinear model of underlying process is not precisely known, but a partially known nominal model is available. This partially known nonlinear model is first decomposed to an affine term plus an unknown high-order term via Jacobian linearization. The linearization residue combined with unmodeled dynamics is then modeled using an extreme learning machine via supervised learning. The minimax methodology is exploited to deal with bounded uncertainties. The minimax optimization problem is reformulated as a convex minimization problem and is iteratively solved by a two-layer recurrent neural network. The proposed neurodynamic approach to nonlinear MPC improves the computational efficiency and sheds a light for real-time implementability of MPC technology. Simulation results are provided to substantiate the effectiveness and characteristics of the proposed approach. PMID:24807443

  18. New Nuclear Emergency Prognosis system in Korea

    NASA Astrophysics Data System (ADS)

    Lee, Hyun-Ha; Jeong, Seung-Young; Park, Sang-Hyun; Lee, Kwan-Hee

    2016-04-01

    This paper reviews the status of assessment and prognosis system for nuclear emergency response in Korea, especially atmospheric dispersion model. The Korea Institute of Nuclear Safety (KINS) performs the regulation and radiological emergency preparedness of the nuclear facilities and radiation utilizations. Also, KINS has set up the "Radiological Emergency Technical Advisory Plan" and the associated procedures such as an emergency response manual in consideration of the IAEA Safety Standards GS-R-2, GS-G-2.0, and GS-G-2.1. The Radiological Emergency Technical Advisory Center (RETAC) organized in an emergency situation provides the technical advice on radiological emergency response. The "Atomic Computerized Technical Advisory System for nuclear emergency" (AtomCARE) has been developed to implement assessment and prognosis by RETAC. KINS developed Accident Dose Assessment and Monitoring (ADAMO) system in 2015 to reflect the lessons learned from Fukushima accident. It incorporates (1) the dose assessment on the entire Korean peninsula, Asia region, and global region, (2) multi-units accident assessment (3) applying new methodology of dose rate assessment and the source term estimation with inverse modeling, (4) dose assessment and monitoring with the environmental measurements result. The ADAMO is the renovated version of current FADAS of AtomCARE. The ADAMO increases the accuracy of the radioactive material dispersion with applying the LDAPS(Local Data Assimilation Prediction System, Spatial resolution: 1.5 km) and RDAPS(Regional Data Assimilation Prediction System, Spatial resolution: 12km) of weather prediction data, and performing the data assimilation of automatic weather system (AWS) data from Korea Meteorological Administration (KMA) and data from the weather observation tower at NPP site. The prediction model of the radiological material dispersion is based on the set of the Lagrangian Particle model and Lagrangian Puff model. The dose estimation methodology

  19. Bounding Species Distribution Models

    NASA Technical Reports Server (NTRS)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  20. Bounding species distribution models

    USGS Publications Warehouse

    Stohlgren, T.J.; Jarnevich, C.S.; Esaias, W.E.; Morisette, J.T.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used. ?? 2011 Current Zoology.

  1. Power conditioning for space nuclear reactor systems

    NASA Technical Reports Server (NTRS)

    Berman, Baruch

    1987-01-01

    This paper addresses the power conditioning subsystem for both Stirling and Brayton conversion of space nuclear reactor systems. Included are the requirements summary, trade results related to subsystem implementation, subsystem description, voltage level versus weight, efficiency and operational integrity, components selection, and shielding considerations. The discussion is supported by pertinent circuit and block diagrams. Summary conclusions and recommendations derived from the above studies are included.

  2. Fission control system for nuclear reactor

    DOEpatents

    Conley, G.H.; Estes, G.P.

    Control system for nuclear reactor comprises a first set of reactivity modifying rods fixed in a reactor core with their upper ends stepped in height across the core, and a second set of reactivity modifying rods movable vertically within the reactor core and having their lower ends stepped to correspond with the stepped arrangement of the first set of rods, pairs of the rods of the first and second sets being in coaxial alignment.

  3. Propagation of surface waves in two-plasma systems bounded by a metallic enclosure

    NASA Astrophysics Data System (ADS)

    Margot, Joëlle; Stafford, Luc; Johnston, Tudor W.

    1999-10-01

    The excitation of surface waves (SW) has been the object of intensive research over the last twenty to thirty years because of their interest in sustaining plasmas under various experimental conditions and configurations. Since the pioneering work having reported the theoretical existence of surface waves in 1959 (Trivelpiece and Gould), it is commonly believed that such waves only exist in plasmas bounded by a dielectric layer. However, some recent numerical and experimental investigations by the groups of Birdsall and Sugai, respectively, indicate that surface waves can be excited in plasmas bounded by a metallic enclosure, the plasma sheath then acting as a dielectric layer. In this presentation, we generalize the theory of surface waves to plasma-plasma-metal configurations in cylindrical geometry. Using a full electromagnetic approach in the cold plasma approximation, we search for SW or pseudo-SW solutions (i.e. solutions that tend toward pure surface waves when the permittivity of the outer plasma approaches unity). We thus determine the dispersion and attenuation characteristics of the waves. We explore situations in which the inner plasma column is either overdense or underdense and we investigate the influence of a magnetic field axial to the plasma columns.

  4. 17O nuclear quadrupole coupling constants of water bound to a metal ion: A gadolinium(III) case study

    NASA Astrophysics Data System (ADS)

    Yazyev, Oleg V.; Helm, Lothar

    2006-08-01

    Rotational correlation times of metal ion aqua complexes can be determined from O17 NMR relaxation rates if the quadrupole coupling constant of the bound water oxygen-17 nucleus is known. The rotational correlation time is an important parameter for the efficiency of Gd3+ complexes as magnetic resonance imaging contrast agents. Using a combination of density functional theory with classical and Car-Parrinello molecular dynamics simulations we performed a computational study of the O17 quadrupole coupling constants in model aqua ions and the [Gd(DOTA)(H2O)]- complex used in clinical diagnostics. For the inner sphere water molecule in the [Gd(DOTA)(H2O)]- complex the determined quadrupole coupling parameter χ√1+η2/3 of 8.7MHz is very similar to that of the liquid water (9.0MHz ). Very close values were also predicted for the the homoleptic aqua ions of Gd3+ and Ca2+. We conclude that the O17 quadrupole coupling parameters of water molecules coordinated to closed shell and lanthanide metal ions are similar to water molecules in the liquid state.

  5. System model development for nuclear thermal propulsion

    SciTech Connect

    Walton, J.T.; Hannan, N.A.; Perkins, K.R.; Buksa, J.J.; Worley, B.A.; Dobranich, D.

    1992-10-01

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented.

  6. An approach to a self-consistent nuclear energy system

    SciTech Connect

    Fujii-e, Yoichi ); Arie, Kazuo; Endo, Hiroshi )

    1992-01-01

    A nuclear energy system should provide a stable supply of energy without endangering the environment or humans. If there is fear about exhausting world energy resources, accumulating radionuclides, and nuclear reactor safety, tension is created in human society. Nuclear energy systems of the future should be able to eliminate fear from people's minds. In other words, the whole system, including the nuclear fuel cycle, should be self-consistent. This is the ultimate goal of nuclear energy. If it can be realized, public acceptance of nuclear energy will increase significantly. In a self-consistent nuclear energy system, misunderstandings between experts on nuclear energy and the public should be minimized. The way to achieve this goal is to explain using simple logic. This paper proposes specific targets for self-consistent nuclear energy systems and shows that the fast breeder reactor (FBR) lies on the route to attaining the final goal.

  7. Shutdown system for a nuclear reactor

    DOEpatents

    Groh, E.F.; Olson, A.P.; Wade, D.C.; Robinson, B.W.

    1984-06-05

    An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion. 8 figs.

  8. Shutdown system for a nuclear reactor

    DOEpatents

    Groh, Edward F.; Olson, Arne P.; Wade, David C.; Robinson, Bryan W.

    1984-01-01

    An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion.

  9. Systems aspects of a space nuclear reactor power system

    NASA Technical Reports Server (NTRS)

    Jaffe, L.; Fujita, T.; Beatty, R.; Bhandari, P.; Chow, E.; Deininger, W.; Ewell, R.; Grossman, M.; Bloomfield, H.; Heller, J.

    1988-01-01

    Various system aspects of a 300-kW nuclear reactor power system for spacecraft have been investigated. Special attention is given to the cases of a reusable OTV and a space-based radar. It is demonstrated that the stowed length of the power system is important to mission design, and that orbital storage for months to years may be needed for missions involving orbital assembly.

  10. Outward Bound.

    ERIC Educational Resources Information Center

    Outward Bound, Inc., Andover, MA.

    The Outward Bound concept was developed in Germany and Great Britain with the saving of human life as the ultimate goal. Courses are designed to help students discover their true physical and mental limits through development of skills including emergency medical aid, firefighting, search and rescue, mountaineering, and sailing. Five Outward Bound…