Citations with the tag: CRITICALITY (Nuclear engineering)

Results 1 - 34

• Self-organized criticality, long-time correlations, and the standard transport paradigm.
  Krommes, John A. // Physics of Plasmas; May2000, Vol. 7 Issue 5, p1752 

  Examines the physical and mathematical descriptions of self-organized criticality. Use of a stochastic model with long-time correlations; Formula for the frequency spectrum of uncorrelated and overlapping avalanches; Argument on the Eulerian correlation functions and local transport coefficients.

• Scaling near the upper critical dimensionality in the localization theory.
  Suslov, I. M. // Journal of Experimental & Theoretical Physics; Apr98, Vol. 86 Issue 4, p798 

  The phenomenon of upper critical dimensionality d[sub c2] has been studied from the viewpoint of the scaling concepts. The Thouless number g(L) is not the only essential variable in scale transformations, because there is the second essential parameter connected with the off-diagonal disorder....

• Criticality and isostaticity in fibre networks.
  Broedersz, Chase P.; Mao, Xiaoming; Lubensky, Tom C.; MacKintosh, Frederick C. // Nature Physics; Dec2011, Vol. 7 Issue 12, p983 

  Disordered fibre networks are the basis of many man-made and natural materials, including structural components of living cells and tissue. The mechanical stability of such networks relies on the bending resistance of the fibres, in contrast to rubbers, which are governed by entropic stretching...

• Magnetic Properties of Two-Dimensional Josephson Networks: Self-Organized Criticality in Magnetic Flux Dynamics.
  Ishikaev, S. M.; Matizen, �. V.; Ryazanov, V. V.; Oboznov, V. A.; Veretennikov, A. V. // JETP Letters; 7/10/2000, Vol. 72 Issue 1, p26 

  The field dependence of the magnetic moment of square (100�100) Josephson networks was examined with the use of a SQUID magnetometer. The field dependence of the magnetic moment was found to be regular with features corresponding to integer and half-integer numbers of flux quanta per cell. At...

• Minding the Store.
  Schroder, R. M. // Power Engineering; Oct2004, Vol. 108 Issue 10, p61 

  Focuses on the management of rarely used inventories in power plants. Factors that contribute to excess inventory; Importance of criticality in inventory management system; Results of an inventory analysis of plants.

• Universality in the fast orientational relaxation near isotropic-nematic transition.
  Ravichandran, S.; Perera, A. // Journal of Chemical Physics; 11/1/1998, Vol. 109 Issue 17, p7349 

  Analyzes the emergence of criticality in the single-particle orientational relaxation near the isotropic-nematic (IN) phase transition by molecular dynamics simulations. Details of the simulation; Molecular dynamics simulation of Lennard-Jones ellipsoids; Implication for isotropic-nematic...

• Neutron spectrum at the center of a cylindrical caisson in the KVANT criticality test stand.
  Sevast'yanov, V. D.; Bykov, A. A.; Volkov, A. E.; Merkushov, N. A. // Measurement Techniques; Feb2010, Vol. 53 Issue 2, p123 

  An activation method is used to measure and calculate the neutron spectrum inside a cylindrical caisson in the KVANT criticality test stand. This is compared with the neutron spectrum near the inner surface of the core housing of the test stand.

• Quantum and classical criticalities in the frustrated two-leg Heisenberg ladder.
  Azzouz, Mohamed; Ramakko, Brandon // Canadian Journal of Physics; Apr2008, Vol. 86 Issue 4, p509 

  This paper is about the frustration-induced criticality in the antiferromagnetic Heisenberg model on the two-leg ladder with exchange interactions along the chains, rungs, and diagonals, and also about the effect of thermal fluctuations on this criticality. The method used is the bond-mean-field...

• Nuclear movers and shakers.
  Azzouz, Mohamed; Ramakko, Brandon // Professional Engineering; 4/27/2005, Vol. 18 Issue 8, p27 

  The article reports that British Nuclear Fuels reached a major landmark in mid-March, making significant steps towards cleaning up one of its oldest problem sites at its Sellafield reprocessing plant on the Cumbrian coast and using world-leading technology in the process. The task was to empty...

• Statistical properties of SGR 1900+14 bursts.
  Go�g?u�s�, Ersin; Woods, Peter M.; Kouveliotou, Chryssa; van Paradijs, Jan; Briggs, Michael S.; Duncan, Robert C.; Thompson, Christopher // AIP Conference Proceedings; 2000, Vol. 526 Issue 1, p796 

  BATSE detected 200 bursts from SGR 1900+14 between May 1998 and January 1999. The reactivation of the bursts initiated a series of RXTE observations within which more than 800 bursts were observed. Here we study statistical characteristics of SGR 1900+14 bursts using BATSE and RXTE observations....

• Self-Organized Criticality and 1/f Fluctuation under Conditions of Nonequilibrium Phase Transitions.
  Skokov, V. N.; Koverda, V. P.; Reshetnikov, A. V. // Journal of Experimental & Theoretical Physics; Mar2001, Vol. 92 Issue 3, p535 

  The results are given of an experimental investigation of fluctuation phenomena under conditions of electric arc discharge. Fluctuations are observed whose spectral density is inversely proportional to frequency (1/f noise). Power dependences are revealed of the fluctuation distribution...

• Heat capacity of the restricted primitive model near criticality.
  Valleau, John; Torrie, Glenn // Journal of Chemical Physics; 4/1/1998, Vol. 108 Issue 13, p5169 

  Investigates the heat capacity of the restricted primitive model near criticality. Use of the Monte Carlo technique in studying the phase transition of the model; Absence of indication of Isong-type divergence of the heat capacity; Occurrence of Ising behavior close to critical point in some...

• Crossover component in non critical dissipative sandpile models.
  Benyoussef, A.; Khfifi, M.; Loulidi, M. // European Physical Journal B -- Condensed Matter; Jan2005, Vol. 43 Issue 2, p213 

  The effect of bulk dissipation on non critical sandpile models is studied using both multifractal and finite size scaling analyses. We show numerically that the local limited (LL) model exhibits a crossover from multifractal to self-similar behavior as the control parameters hext and epsilon...

• Scale-free avalanches in the multifractal random walk.
  Bartolozzi, M. // European Physical Journal B -- Condensed Matter; Jun2007, Vol. 57 Issue 3, p337 

  Avalanches, or Avalanche-like, events are often observed in the dynamical behaviour of many complex systems which span from solar flaring to the Earth's crust dynamics and from traffic flows to financial markets. Self-organized criticality (SOC) is one of the most popular theories able to...

• Short-time dynamics in the 1D long-range Potts model.
  Uzelac, K.; Glumac, Z.; Bari�ic, O. S. // European Physical Journal B -- Condensed Matter; May2008, Vol. 63 Issue 1, p101 

  We present numerical investigations of the short-time dynamics at criticality in the 1D Potts model with power-law decaying interactions of the form 1/r1+s. The scaling properties of the magnetization, autocorrelation function and time correlations of the magnetization are studied. The dynamical...

• Sellafield plans mox fuel handling plant.
  Uzelac, K.; Glumac, Z.; Bari�ic, O. S. // Professional Engineering; 6/15/2005, Vol. 18 Issue 11, p11 

  This article informs that British Nuclear Fuels (BNFL) is to build a handling facility at Sellafield in response to its growing mixed-oxide (mox) fuel business. The first mox shipment since 1999's data falsification scandal was delivered to Swiss generator NOK earlier this month, 12 years after...

• Olami-Feder-Christensen model on different networks.
  Caruso, F.; Latora, V.; Pluchino, A.; Rapisarda, A.; Tadic, B. // European Physical Journal B -- Condensed Matter; Mar2006, Vol. 50 Issue 1/2, p243 

  We investigate numerically the Self Organized Criticality (SOC) properties of the dissipative Olami-Feder-Christensen model on small-world and scale-free networks. We find that the small-world OFC model exhibits self-organized criticality. Indeed, in this case we observe power law behavior of...

• Jerarquizaci�n del Reemplazo de Equipos Productivos de Acuerdo a su Nivel de Cumplimiento de los Objetivos de la Empresa.
  Espinosa, Fernando F.; Salinas, Gonzalo E.; Leiva, Pedro P. // Informaci�n Tecnol�gica; 2011, Vol. 22 Issue 4, p97 

  In this paper the computational implementation of a model for the administrator of industrial maintenance, the person who must decide about the priority in which the productive equipments in a company should be replaced. The system takes into account the level of importance in the evolution of...

• Sensitivity to Initial Conditions in Self-Organized Critical Systems.
  Stapleton, Matthew; Dingler, Martin; Christensen, Kim // Journal of Statistical Physics; Dec2004, Vol. 117 Issue 5/6, p891 

  We discuss sensitivity to initial conditions in a model for avalanches in granular media displaying self-organized criticality. We show that damage, due to a small perturbation in initial conditions, does not spread. The damage persists in a statistically time-invariant and scale-free form. We...

• IMPDOS (IMPROVED DOSIMETRY AND RISK ASSESSMENT FOR PLUTONIUM-INDUCED DISEASES): INTERNAL DOSIMETRY SOFTWARE TOOLS DEVELOPED FOR THE MAYAK WORKER STUDY.
  MiIIer, G.; Bertelli, L.; Guilmette, R. // Radiation Protection Dosimetry; 2008, Vol. 131 Issue 3, p308 

  A collection of software tools developed for the Mayak worker study is described. IMPDOS is software for modelling, data analysis, and activity and dose calculations using the bioassay and postmortem data from Mayak workers provided by Southern Urals Biophysics Institute. The capabilities...

• Simulating critical dynamics in liquid mixtures: Short-range and long-range contributions.
  Das, Subir K.; Sengers, Jan V.; Fisher, Michael E. // Journal of Chemical Physics; 10/14/2007, Vol. 127 Issue 14, p144506 

  Recently, Das et al. [J. Chem. Phys. 125, 024506 (2006)] established that computer simulations of critical dynamics in a binary Lennard-Jones mixture are consistent with the predicted Stokes-Einstein behavior of the asymptotic decay rate of the order-parameter fluctuations near criticality....

• Monte Carlo Simulation of BN-600 LMFR Hybrid Core.
  HassaN, Mohga I.; Aziz, Moustafa // Journal of Materials Science & Engineering B; 2011, Vol. 1 Issue 6B, p838 

  MCNPX code is used to design a three dimensional model to simulate and study the whole hybrid core of the BN-600 prototype LMFR. In the model, the core is composed of eight radial zones and eight axial zones. The spectrum of neutron flux is divided into 23 energy groups. Results from this model...

• Study of the Doppler reactivity effect for samples of reactor materials in critical assemblies.
  Tambovtsev, S.; Doulin, V.; Raskach, K. // Atomic Energy; Jan2013, Vol. 113 Issue 3, p201 

  The need to check the accuracy of evaluations of the constant component of the Doppler reactivity effect, which depends on cross sections, self-screening factors, and the neutron spectrum, is addressed. The problem of studying the Doppler effect of samples of reactor materials by perturbation of...

• Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4.
  Nakatsuji, S.; Kuga, K.; Machida, Y.; Tayama, T.; Sakakibara, T.; Karaki, Y.; Ishimoto, H.; Yonezawa, S.; Maeno, Y.; Pearson, E.; Lonzarich, G. G.; Balicas, L.; Lee, H.; Fisk, Z. // Nature Physics; Aug2008, Vol. 4 Issue 8, p603 

  A long-standing question in the field of superconductivity is whether pairing of electrons can arise in some cases as a result of magnetic interactions instead of electron–phonon-induced interactions as in the conventional Bardeen–Cooper–Schrieffer theory. A major challenge to the idea of...

• Criticality Calculations for Step-2 GPHS Modules.
  Lipinski, Ronald J.; Hensen, Danielle L. // AIP Conference Proceedings; 1/21/2008, Vol. 969 Issue 1, p452 

  The Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) will use an improved version of the General Purpose Heat Source (GPHS) module as its source of thermal power. This new version, referred to as the Step-2 GPHS Module, has additional and thicker layers of carbon fiber material (Fine...

• NEUTRON CROSS SECTION MEASUREMENTS AT ORELA FOR IMPROVED NUCLEAR DATA AND THEIR APPLICATION.
  Guber, K. H.; Leal, L. C.; Sayer, R. O.; Koehler, P. E.; Valentine, T. E.; Derrien, H.; Harvey, J. A. // Radiation Protection Dosimetry; 2005, Vol. 116 Issue 1-4, p579 

  To support the Nuclear Criticality Safety Program, the Oak Ridge Electron Linear Accelerator (ORELA) has been used to measure the total and capture neutron cross sections of several nuclides in the energy range from 100 eV to ∼600 keV. Concerns about the use of existing cross section data in...

• Speculative Data and the Creative Imaginary: Shared Visions between Art and Technology.
  Guber, K. H.; Leal, L. C.; Sayer, R. O.; Koehler, P. E.; Valentine, T. E.; Derrien, H.; Harvey, J. A. // Issues in Science & Technology; Spring2007, Vol. 23 Issue 3, p6 

  The article offers information on the Speculative Data and the Creative Imaginary exhibition that will be held at the National Academy of Sciences Rotunda Gallery in Washington, D.C., from June 3 to August 24, 2007. Works in the Speculative Data and the Creative Imaginary exhibition represent a...

• Fuel Breeding and Core Behavior Analyses on In Core Fuel Management of Water Cooled Thorium Reactors.
  Permana, Sidik; Sekimoto, Hiroshi; Waris, Abdul; Subhki, Muhamad Nurul; Ismail // AIP Conference Proceedings; 12/27/2010, Vol. 1325 Issue 1, p229 

  Thorium fuel cycle with recycled U-233 has been widely recognized having some contributions to improve the water-cooled breeder reactor program which has been shown by a feasible area of breeding and negative void reactivity which confirms that fissile of 233U contributes to better fuel breeding...

• Flagging Critical Components to Prevent Transient Faults in Real-Time Systems.
  Sadi, Muhammad Sheikh; Myers, D. G.; Sanchez, Cesar Ortega // Proceedings of World Academy of Science: Engineering & Technolog; Apr2008, Vol. 40, p223 

  This paper proposes the use of metrics in design space exploration that highlight where in the structure of the model and at what point in the behaviour, prevention is needed against transient faults. Previous approaches to tackle transient faults focused on recovery after detection. Almost no...

• Criticality analysis of activity networks under interval uncertainty.
  Fortin, J�r�me; Zielinski, Pawel; Dubois, Didier; Fargier, H�l�ne // Journal of Scheduling; Dec2010, Vol. 13 Issue 6, p609 

  This paper reconsiders the Project Evaluation and Review Technique (PERT) scheduling problem when information about task duration is incomplete. We model uncertainty on task durations by intervals. With this problem formulation, our goal is to assert possible and necessary criticality of the...

• Nuclear Society to Revise Emergency Planning & Response Standard.
  Fortin, J�r�me; Zielinski, Pawel; Dubois, Didier; Fargier, H�l�ne // Professional Safety; Feb2007, Vol. 52 Issue 2, p51 

  The article reports on the revision of Nuclear Critically Accident Emergency Planning and Response by the American Nuclear Society (ANS) in the U.S. ANS has been revising the Nuclear Critically Accident Emergency Planning and Response standard (Business for Social Responsibility/ ANS 8.23-200x)....

• DNFSB Sees Criticality, Explosion Risks At Hanford Waste Plant.
  Lobsenz, George // Energy Daily; 1/8/2010, p3 

  The article focuses on safety issues raised by the U.S. Defense Nuclear Facilities Safety Board (DNFSB) regarding the pulse jet mixing technology being installed in the Hanford nuclear waste treatment plant in Washington. The DNFSB notes the insufficiency of the technology to prevent the...

• Nuclear Fuel: Prospects and Production.
  Johnson, Jesse C. // Bulletin of the Atomic Scientists; Jun1959, Vol. 15 Issue 6, p245 

  The article offers a critical look on the prospects and production of nuclear fuel. According to the author, most of the significant uranium-producing nations have slew virtually all security restrictions on information relating to nuclear raw materials since 1955. For him, it is important that...

• Undergraduate Measurements For Fission Reactor Applications.
  Hicks, S. F.; Kersting, L. J.; Lueck, C. J.; McDonough, P.; Crider, B. P.; McEllistrem, M. T.; Peters, E. E.; Vanhoy, J. R. // AIP Conference Proceedings; 6/1/2011, Vol. 1336 Issue 1, p738 

  Undergraduate students at the University of Dallas (UD) have investigated elastic and inelastic neutron scattering cross sections on structural materials important for criticality considerations in nuclear fission processes. Neutrons scattered off of 23Na and NatFe were detected using neutron...