Relevant bibliographies by topics / LWR models

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'LWR models'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'LWR models.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "LWR models"

1

Oriolo, Francesco, and Sandro Paci. "Heat and mass transfer models in LWR containment systems." Nuclear Engineering and Design 204, no. 1-3 (February 2001): 233–50. http://dx.doi.org/10.1016/s0029-5493(00)00314-9.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Chopra, O. K., and W. J. Shack. "Overview of Fatigue Crack Initiation in Carbon and Low-Alloy Steels in Light Water Reactor Environments." Journal of Pressure Vessel Technology 121, no. 1 (February 1, 1999): 49–60. http://dx.doi.org/10.1115/1.2883667.

Full text
Abstract:
Recent test data illustrate potentially significant effects of light water reactor (LWR) coolant environments on the fatigue resistance of carbon and low-alloy steels. The crack initiation and crack growth characteristics of carbon and low-alloy steels in LWR environments are presented. Decreases in fatigue lives of these steels in high-dissolved-oxygen water are caused primarily by the effect of environment on growth of short cracks <100 μm in depth. The material and loading parameters that influence fatigue life in LWR environments are defined. Statistical models have been developed to estimate the fatigue lives of these steels in LWR environments, and design fatigue curves have been developed for carbon and low-alloy steel components in LWR environments. The significance of environmental effect on the current Code design curve is evaluated.
APA, Harvard, Vancouver, ISO, and other styles
3

Zhang, H. M., and T. Kim. "Effects of Relaxation and Anticipation on Riemann Solutions of Payne-Whitham Model." Transportation Research Record: Journal of the Transportation Research Board 1710, no. 1 (January 2000): 131–35. http://dx.doi.org/10.3141/1710-15.

Full text
Abstract:
The solutions of Riemann problems of a particular higher-order model—the Payne-Whitham (PW) model—are studied using Roe’s flux splitting scheme as presented by Leo and Pretty. Despite numerous works on higher-order models, little is known about Riemann solutions of these models and how relaxation and anticipation affect these solutions. Riemann solutions of the PW model are computed and compared with those of the Lighthill-Whitham-Richards (LWR) model having the same initial (density) data. It was found that faster relaxation forces the PW model to behave much like the LWR model, that strong anticipation has a stabilizing effect on traffic, and that shock waves travel at different speeds in the PW model than they do in the LWR model. These findings provide a basic checklist for experimental validation of PW-like higher models.
APA, Harvard, Vancouver, ISO, and other styles
4

Raza, Asif, and Ming Zhong. "Lane-based short-term urban traffic parameters forecasting using multivariate artificial neural network and locally weighted regression models: A genetic approach." Canadian Journal of Civil Engineering 46, no. 5 (May 2019): 371–80. http://dx.doi.org/10.1139/cjce-2017-0644.

Full text
Abstract:
Short-term prediction of traffic conditions on urban arterials has recently become increasingly important because of its vital role in the basic traffic management functions and trip decision-making processes. Such information is useful for optimal infrastructure operation, routing, and trip scheduling. However, forecasting models offering a high accuracy at a fine temporal resolution (e.g., 1 or 5 min) and, especially, lane-based are still rare and need special attention. Given the dynamic and stochastic nature of traffic, this study proposes a genetically optimized artificial neural network (GA-ANN) and locally weighted regression (GA-LWR) multivariate models, for short-term traffic prediction using a combination of multiple traffic variables such as volume, occupancy, and speed, during peak and off-peak periods. The proposed 5-min GA-ANN and GA-LWR disaggregate multivariate models show lower average and 95th percentile (P95) errors, when compared to those reported in the literature. In particular, for peak and off-peak time prediction, the GA-ANN disaggregate multivariate models result in most of the average errors being from 2% to 5% and the 95th percentile errors being from 9% to 10%. On the other hand, for peak and off-peak time traffic prediction, the GA-LWR disaggregate multivariate models show that most of the average errors are lower than 5% and the 95th percentile errors are lower than 10%. Meanwhile, for peak and off-peak time prediction, both GA-ANN and GA-LWR disaggregates models show lower MSE of 0.11–1.84. Hence, such techniques are believed useful for developing a robust urban traffic forecasting system.
APA, Harvard, Vancouver, ISO, and other styles
5

Qin, Yanyan, Hao Wang, and Daiheng Ni. "Lighthill-Whitham-Richards Model for Traffic Flow Mixed with Cooperative Adaptive Cruise Control Vehicles." Transportation Science 55, no. 4 (July 2021): 883–907. http://dx.doi.org/10.1287/trsc.2021.1057.

Full text
Abstract:
In the future, road traffic will incorporate a random mix of manual vehicles and cooperative adaptive cruise control (CACC) vehicles, where a CACC vehicle will degrade to an adaptive cruise control (ACC) vehicle when vehicle-to-vehicle communications are not available. This paper proposes a generalized framework of the Lighthill-Whitham-Richards (LWR) model for such mixed vehicular flow under different CACC penetration rates. In this approach, the kinematic wave speed propagating through the mixed platoon was theoretically proven to be the slope of mixed fundamental diagram. In addition, the random degradation from CACC to ACC was captured in mathematical expectation for traffic scenarios where the CACC only monitors one vehicle ahead. Three concrete car-following models, the intelligent driver model (IDM) and CACC/ACC models validated by Partners for Advanced Transit and Highways (PATH) program, were selected as examples to investigate the propagation of small perturbations and shock waves. Numerical simulations were also performed based on the selected car-following models. Moreover, the derived mixed LWR model was applied to solve some traffic flow problems. It indicates that the proposed LWR model is able to describe the propagation properties of both small perturbations and shock waves. The mixed LWR model can also be used to solve some practical problems, such as the queue caused by a traffic accident and the impact of a moving bottleneck. More importantly, the proposed generalized framework admits other CACC/ACC/regular car-following models, including those developed from further experiments.
APA, Harvard, Vancouver, ISO, and other styles
6

Iftikhar, Amir, Zawar H. Khan, T. Aaron Gulliver, Khurram S. Khattak, Mushtaq A. Khan, Murtaza Ali, and Nasru Minallahe. "Macroscopic Traffic Flow Characterization at Bottlenecks." Civil Engineering Journal 6, no. 7 (July 1, 2020): 1227–42. http://dx.doi.org/10.28991/cej-2020-03091543.

Full text
Abstract:
Traffic congestion is a significant issue in urban areas. Realistic traffic flow models are crucial for understanding and mitigating congestion. Congestion occurs at bottlenecks where large changes in density occur. In this paper, a traffic flow model is proposed which characterizes traffic at the egress and ingress to bottlenecks. This model is based on driver response which includes driver reaction and traffic stimuli. Driver reaction is based on time headway and driver behavior which can be classified as sluggish, typical or aggressive. Traffic stimuli are affected by the transition width and changes in the equilibrium velocity distribution. The explicit upwind difference scheme is used to evaluate the Lighthill, Whitham, and Richards (LWR) and proposed models with a continuous injection of traffic into the system. A stability analysis of these models is given and both are evaluated over a road of length 10 km which has a bottleneck. The results obtained show that the behavior with the proposed model is more realistic than with the LWR model. This is because the LWR model cannot adequately characterize driver behavior during changes in traffic flow.
APA, Harvard, Vancouver, ISO, and other styles
7

Imran, Waheed, Zawar H. Khan, T. A. Gulliver, Khurram S. Khattak, Salman Saeed, and M. Sagheer Aslam. "Macroscopic Traffic Flow Characterization for Stimuli Based on Driver Reaction." Civil Engineering Journal 7, no. 1 (January 1, 2021): 1–13. http://dx.doi.org/10.28991/cej-2021-03091632.

Full text
Abstract:
The design and management of infrastructure is a significant challenge for traffic engineers and planners. Accurate traffic characterization is necessary for effective infrastructure utilization. Thus, models are required that can characterize a variety of conditions and can be employed for homogeneous, heterogeneous, equilibrium and non-equilibrium traffic. The Lighthill-Whitham-Richards (LWR) model is widely used because of its simplicity. This model characterizes traffic behavior with small changes over a long idealized road and so is inadequate for typical traffic conditions. The extended LWR model considers driver types based on velocity to characterize traffic behavior in non lane discipline traffic but it ignores the stimuli for changes in velocity. In this paper, an improved model is presented which is based on driver reaction to forward traffic stimuli. This reaction occurs over the forward distance headway during which traffic aligns to the current conditions. The performance of the proposed, LWR and extended LWR models is evaluated using the first order upwind scheme (FOUS). The numerical stability of this scheme is guaranteed by employing the Courant, Friedrich and Lewy (CFL) condition. Results are presented which show that the proposed model can characterize both small and large changes in traffic more realistically. Doi: 10.28991/cej-2021-03091632 Full Text: PDF
APA, Harvard, Vancouver, ISO, and other styles
8

Toptan, Aysenur, Nathan W. Porter, Robert K. Salko, and Maria N. Avramova. "Implementation and assessment of wall friction models for LWR core analysis." Annals of Nuclear Energy 115 (May 2018): 565–72. http://dx.doi.org/10.1016/j.anucene.2018.02.022.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Hou, Jason, Maria Avramova, and Kostadin Ivanov. "Best-Estimate Plus Uncertainty Framework for Multiscale, Multiphysics Light Water Reactor Core Analysis." Science and Technology of Nuclear Installations 2020 (July 31, 2020): 1–18. http://dx.doi.org/10.1155/2020/7526864.

Full text
Abstract:
Tremendous work has been done in the Light Water Reactor (LWR) Modelling and Simulation (M&S) uncertainty quantification (UQ) within the framework of the Organization for Economic Cooperation and Development (OECD)/Nuclear Energy Agency (NEA) LWR Uncertainty Analysis in Modelling (UAM) benchmark, which aims to investigate the uncertainty propagation in all M&S stages of the LWRs and to guide uncertainty and sensitivity analysis methodology development. The Best-Estimate Plus Uncertainty (BEPU) methodologies have been developed and implemented within the framework of the LWR UAM benchmark to provide a realistic predictive simulation capability without compromising the safety margins. This paper describes the current status of the methodological development, assessment, and integration of the BEPU methodology to facilitate the multiscale, multiphysics LWR core analysis. The comparative analysis of the results in the stand-alone multiscale neutronics phase (Phase I) is first reported for understanding the general trend of the uncertainty of core parameters due to the nuclear data uncertainty. It was found that the predicted uncertainty of the system eigenvalue is highly dependent on the choice of the covariance libraries used in the UQ process and is less sensitive to the solution method, nuclear data library, and UQ method. High-to-Low (Hi2Lo) model information approaches for multiscale M&S are introduced for the core single physics phase (Phase II). In this phase, the other physics (fuel and moderator), providing feedback to neutronics M&S in a LWR core, and time-dependent phenomena are considered. Phase II is focused on uncertainty propagation in single physics models which are components of the LWR core coupled multiphysics calculations. The paper discusses the link and interactions between Phase II to the multiphysics core and system phase (Phase III), that is, the link between uncertainty propagation in single physics on local scale and multiphysics uncertainty propagation on the core scale. Particularly, the consistency in uncertainty assessment between higher-fidelity models implemented in fuel performance codes and the rather simplified models implemented in thermal-hydraulics codes, to be used for coupling with neutronics in Phase III is presented. Similarly, the uncertainty quantification on thermal-hydraulic models is established on a relatively small scale, while these results will be used in Phase III at the core scale, sometimes with different codes or models. Lastly, the up-to-date UQ method for the coupled multiphysics core calculation in Phase III is presented, focusing on the core equilibrium cycle depletion calculation with associated uncertainties.
APA, Harvard, Vancouver, ISO, and other styles
10

Briani, Maya, Emiliano Cristiani, and Paolo Ranut. "Macroscopic and Multi-Scale Models for Multi-Class Vehicular Dynamics with Uneven Space Occupancy: A Case Study." Axioms 10, no. 2 (May 24, 2021): 102. http://dx.doi.org/10.3390/axioms10020102.

Full text
Abstract:
In this paper, we propose two models describing the dynamics of heavy and light vehicles on a road network, taking into account the interactions between the two classes. The models are tailored for two-lane highways where heavy vehicles cannot overtake. This means that heavy vehicles cannot saturate the whole road space, while light vehicles can. In these conditions, the creeping phenomenon can appear, i.e., one class of vehicles can proceed even if the other class has reached the maximal density. The first model we propose couples two first-order macroscopic LWR models, while the second model couples a second-order microscopic follow-the-leader model with a first-order macroscopic LWR model. Numerical results show that both models are able to catch some second-order (inertial) phenomena such as stop and go waves. Models are calibrated by means of real data measured by fixed sensors placed along the A4 Italian highway Trieste–Venice and its branches, provided by Autovie Venete S.p.A.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "LWR models"

1

Ježková, Jitka. "Modelování dopravního toku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232180.

Full text
Abstract:
Tato diplomová práce prezentuje problematiku dopravního toku a jeho modelování. Zabývá se především několika LWR modely, které následně rozebírá a hledá řešení pro počáteční úlohy. Ukazuje se, že ne pro všechny počáteční úlohy lze řešení definovat na celém prostoru, ale jen v určitém okolí počáteční křivky. Proto je dále odvozena metoda výpočtu velikosti tohoto okolí a to nejen zcela obecně, ale i pro dané modely. Teoretický rozbor LWR modelů a řešení počátečních úloh jsou demonstrovány několika příklady, které zřetelně ukazují, jak se dopravní tok simulovaný danými modely chová.
APA, Harvard, Vancouver, ISO, and other styles
2

Grundmann, Ulrich, Ulrich Rohde, Siegfried Mittag, and Sören Kliem. "DYN3D version 3.2 - code for calculation of transients in light water reactors (LWR) with hexagonal or quadratic fuel elements - description of models and methods -." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-28604.

Full text
Abstract:
DYN3D is an best estimate advanced code for the three-dimensional simulation of steady-states and transients in light water reactor cores with quadratic and hexagonal fuel assemblies. Burnup and poison-dynamic calculations can be performed. For the investigation of wide range transients, DYN3D is coupled with system codes as ATHLET and RELAP5. The neutron kinetic model is based on the solution of the three-dimensional two-group neutron diffusion equation by nodal expansion methods. The thermal-hydraulics comprises a one- or two-phase coolant flow model on the basis of four differential balance equations for mass, energy and momentum of the two-phase mixture and the mass balance for the vapour phase. Various cross section libraries are linked with DYN3D. Systematic code validation is performed by FZR and independent organizations.
APA, Harvard, Vancouver, ISO, and other styles
3

Grundmann, Ulrich, Ulrich Rohde, Siegfried Mittag, and Sören Kliem. "DYN3D version 3.2 - code for calculation of transients in light water reactors (LWR) with hexagonal or quadratic fuel elements - description of models and methods -." Forschungszentrum Rossendorf, 2005. https://hzdr.qucosa.de/id/qucosa%3A21687.

Full text
Abstract:
DYN3D is an best estimate advanced code for the three-dimensional simulation of steady-states and transients in light water reactor cores with quadratic and hexagonal fuel assemblies. Burnup and poison-dynamic calculations can be performed. For the investigation of wide range transients, DYN3D is coupled with system codes as ATHLET and RELAP5. The neutron kinetic model is based on the solution of the three-dimensional two-group neutron diffusion equation by nodal expansion methods. The thermal-hydraulics comprises a one- or two-phase coolant flow model on the basis of four differential balance equations for mass, energy and momentum of the two-phase mixture and the mass balance for the vapour phase. Various cross section libraries are linked with DYN3D. Systematic code validation is performed by FZR and independent organizations.
APA, Harvard, Vancouver, ISO, and other styles
4

Formánek, Martin. "Výukový model pro mechatroniku: vývoj modelu a rychlé komunikace pomocí USB." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417789.

Full text
Abstract:
Táto diplomová práca sa zaoberá návrhom a realizáciou výukového modelu pre študentov mechatroniky na vysokej škole. Úvod práce sa zaoberá krátkym uvedením do problematiky používania univerzálnej sériovej zbernice a jej implementáciou pre komunikáciu s mikrokontrolérom. Druhá časť je venovaná hardwaru zariadenia, medzi čo patrí voľba vhodného motoru, návrh vhodných elektronických komponentov, návrh dosiek plošných spojov a taktiež mechanickej konštrukcie celého zariadenia. Nasleduje softwarová časť, popisujúca praktickú realizáciu komunikácie, program v mikrokontroléry, a Toolbox, ktorý umožňuje užívateľovi jednoduchú interakciu s hardwarom a to jak z Matlabu. tak zo Simulinku. Kombinácia navrhnutých hardwarových a softwarových prvkov umožňuje jednoduchú cestu k zlepšeniu vedomostí študentov v oblastiach programovania, riadenia a modelovaní sústav. Pre tieto účely je práca rozšírená o pracovný list, ktorý dopĺňa navrhnuté zariadenie o sadu experimentálnych úloh, zameraných na vybrané mechatronické problémy.
APA, Harvard, Vancouver, ISO, and other styles
5

Gasik, Kevin Richard. "COMPARISON OF LQR AND LQR-MRAC FOR LINEAR TRACTOR-TRAILER MODEL." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2117.

Full text
Abstract:
The United States trucking industry is immense. Employing over three million drivers and traveling to every city in the country. Semi-Trucks travel millions of miles each week and encompass roads that civilians travel on. These vehicles should be safe and allow efficient travel for all. Autonomous vehicles have been discussed in controls for many decades. Now fleets of autonomous vehicles are beginning their integration into society. The ability to create an autonomous system requires domain and system specific knowledge. Approaches to implement a fully autonomous vehicle have been developed using different techniques in control systems such as Kalman Filters, Neural Networks, Model Predictive Control, and Adaptive Control. However some of these control techniques require superb models, immense computing power, and terabytes of storage. One way to circumvent these issues is by the use of an adaptive control scheme. Adaptive control systems allow for an existing control system to self-tune its performance for unknown variables i.e. when an environment changes. In this thesis a LQR error state control system is derived and shown to maintain a magnitude of 15 cm of steady state error from the center-line of the road. In addition a proposed LQR-MRAC controller is used to test the robustness of a lane-keeping control system. The LQR-MRAC controller was able to improve its transient response peak error from the center-line of the road of the tractor and the trailer by 9.47 [cm] and 7.27 [cm]. The LQR-MRAC controller increased tractor steady state error by 0.4 [cm] and decreased trailer steady state error by 1 [cm]. The LQR-MRAC controller was able to outperform modern control techniques and can be used to improve the response of the tractor-trailer system to handle mass changes in its environment.
APA, Harvard, Vancouver, ISO, and other styles
6

Bergersen, Bjørnar Dolva. "Numerical Solutions of Traffic Flow on Networks : Using the LWR-Model and the Godunov Scheme." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25103.

Full text
Abstract:
This paper shows how to create a simulationtool for traffic flow in a network using the Lighthill--Witham--Richards model and the Godunov scheme. First some basic rules about conservation laws are described and how to solve them using the method characteristics. This leads to the notion of weak solutions which can be solved by shock- and rarefractions-solutions. This is then used to describe how traffic behaves on a single road by using the LWR-model. The behavior of traffic at junctions is discussed, more specifically how to find the maximum flux through a junction when we deal with different amount of incoming and outgoing roads. The paper gives different examples of numerical solution methods to conservation laws, which gives motivation for the Godunov scheme. A numerical scheme using the LWR-model and the Godunov scheme is tested on different traffic models. The main test is a simplified model of Trondheim, Norway. The results are presented in videos, as well as graphs and tables that show the duration of the driving time through different routes of the model.
APA, Harvard, Vancouver, ISO, and other styles
7

Viswanathan, Vishnu. "Improving the dynamical model of the Moon using lunar laser ranging (LLR) and spacecraft data." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEO005/document.

Full text
Abstract:
L'objectif principal de ce travail était d'améliorer le modèle dynamique de la Lune dans les éphémérides numériques INPOP et d’exploiter cette amélioration en vu d’une meilleure caractérisation de la structure interne de la Lune et d’effectuer des tests de la relativité générale. Dans un premier temps, un travail d’analyse des algorithmes nécessaires aux calculs des points normaux utilisés pour la construction des éphémérides lunaire a été effectué. Une analyse approfondie des procédures utilisées par l’équipe de Grasse montre l'impact du choix de l’algorithme sur le calcul de l'incertitude. L'importance de l'incertitude du point normal se reflète dans la méthode du moindre carré pondéré utilisée pour la construction des éphémérides. En particulier, l'absence d'un algorithme standardisé entre les différentes stations LLR introduit des biais dans l’estimation des incertitudes qu’il est important de prendre en compte. La thèse a également bénéficié d'un ensemble de données plus dense en raison des améliorations techniques et du passage de la longueur d'onde à l'infrarouge à la station de Grasse (Courde et al., 2017). Dans un second temps, afin de permettre des analyses multi-techniques combinant mesures SLR et LLR, la réduction des observations LLR a été introduite dans le logiciel de détermination d'orbites GINS du CNES. La modélisation suit les recommandations de IERS et été validée par une comparaison étape par étape avec les groupes d'analyse LLR de l’Observatoire de Paris et à Hanovre avec une précision de l’ordre de 1 mm. En outre, la correction des effets due au chargement hydrologique observé à la station Grasse a été mise en œuvre et a fait l’objet d’une première communication poster en 2016 (Mémin et al. 2016). Une version améliorée du modèle de réduction LLR a été intégrée à la dernière version distribuée du logiciel GINS par l’équipe de géodésie spatiale (GRGS) du CNES.Le modèle dynamique lunaire d’INPOP a d'abord été développé par Manche (2011). Cependant, en raison de l'absence du noyau fluide dans la version précédente (INPOP13c), les résidus obtenus après ajustement étaient au niveau de 5 cm pour la période moderne (2006). Une comparaison détaillée des équations dynamiques avec les éphémérides JPL DE430 a permis d'identifier les changements requis dans INPOP pour l'activation du noyau liquide lunaire. D'autres modifications ont permis l'utilisation d'un champ de gravité lunaire déterminé par la mission spatiale GRAIL. L'utilisation d'un algorithme de moindres carrés sous contraintes a aussi été utilisé afin de maintenir les paramètres connus dans des bornes compatibles avec leurs incertitudes. La nouvelle éphéméride (INPOP17a) produit un résidu de 1,4 à 1,8 cm, compatible avec (Folkner et al. 2014) et (Pavlov et al. 2016). INPOP17a est distribuée sur le site de l’imcce (www.imcce.fr/inpop) et une documentation a été publiée (Viswanathan et al. 2017) dans les notes scientifiques de l’imcce.En outre, en fournissant des contraintes plus sévères dans le modèle dynamique sur le champ de gravité lunaire à partir de l'analyse des données GRAIL, une signature caractéristique de libration lunaire avec une période de 6 ans a été révélée avec une amplitude de +/- 5 mm. Plusieurs pistes ont été étudiées pour l'identification de cet effet, impliquant des termes de marée et des composants de couple à plus haut degré. Cela reste encore un travail en cours, qui se poursuivra grâce à un contrat postdoctoral à Paris. Une publication est en cours de révision à ce sujet.Les résidus au niveau d'un centimètre permettent des tests précis du principe d'équivalence dans le système solaire. La valeur ajustée du paramètre caractérisant l'accélération différentielle de la Terre et de la Lune vers le Soleil a été obtenue et les résultats sont conformes aux travaux antérieurs (Williams et al 2012, Hofmann et al. 2016). Une interprétation en terme de théorie du dilaton est proposée. Une publication est en cours de finalisation
The main goal of the Ph.D. thesis of Vishnu Viswanathan was to improve the dynamical model of the Moon within the numerically integrated ephemeris (INPOP) and to derive results of scientific value from this improvement through the characterization of the lunar internal structure and tests of general relativity.At first, raw binaries of LLR echoes obtained from the Grasse ILRS station was used to analyze the algorithm used by the facility, for the computation of a normal point from the full-rate data. Further analysis shows the dependence of the algorithm on the reported uncertainty contained within the distributed LLR normal points from Grasse. The importance of the normal point uncertainty is reflected in the weighted least square procedure used for parameter estimation, especially in the absence of a standardized algorithm between different LLR ground stations. The thesis also benefitted in terms of a more dense dataset due to technical improvements and the switch of operational wavelength to infrared at the Grasse LLR facility (Courde et al. 2017).The reduction of the LLR observations was carried out on GINS orbit determination software from CNES. The modeling follows the IERS 2010 recommendations for the correction of all known effects on the light-time computation. The subroutines were verified through a step by step comparison study using simulated data, with LLR analysis groups in Paris and Hannover, maintaining any discrepancies in the Earth-Moon distance below 1mm. Additionally, correction of effects due to hydrological loading observed at the Grasse station has been implemented. An improved version of the LLR reduction model was submitted to the space geodesy team of CNES (GRGS).The lunar dynamical model of INPOP was first developed by Manche (2011). However, due to the absence of the fluid core within the previous version of INPOP (13c), the residuals obtained after a least-square fit were in the level of 5cm for the modern day period (2006 onwards). A detailed comparison of the dynamical equations with DE430 JPL ephemeris helped to identify required changes within INPOP for the activation of the lunar fluid core. Other modifications allowed the use of a spacecraft determined lunar gravity field within the dynamical model. The use of a bounded value least square algorithm during the regression procedure accounted for variability to well-known parameters from their reported uncertainties. The resulting iteratively fit solution of INPOP ephemeris then produces a residual of 1.4-1.8 cm, on par with that reported by Folkner et al. 2014 and Pavlov et al. 2016. The new INPOP ephemeris (INPOP17a) is distributed through the IMCCE website (www.imcce.fr/inpop) with a published documentation (Viswanathan et al. 2017) in the scientific notes of IMCCE.Furthermore, on providing tighter constraints on the lunar gravity field from GRAIL-data analysis within the dynamical model, a characteristic lunar libration signature with a period of 6 years was revealed with an amplitude of +/- 5mm. Several tracks were investigated for the identification of the unmodelled effect, involving higher degree tidal terms and torque components. This remains as a work in progress, which will be continued through a postdoctoral contract in Paris. A publication is under revision on this subject.Residuals at the level of a centimeter allow precision tests of the principle of equivalence in the solar system. The fitted value of the parameter characterizing the differential acceleration of the Earth and the Moon towards the Sun was obtained with numerically integrated partial derivatives. The results are consistent with the previous work by Williams et al (2009, 2012), and Hofmann et al. (2010, 2016). An article on this work is in preparation
APA, Harvard, Vancouver, ISO, and other styles
8

Krampoťák, Štefan. "Model dopravních situací." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219706.

Full text
Abstract:
This master thesis deals with analyze of camera system in real traffic, using these system and realization of traffic situation model. Result of this work is fully functional model of traffic situation, which shows the capability of these camera systems in real traffic. It consists of two basic parts, the first is physical model of traffic with semaphore and second part is control program with algorithm for detection of traffic offences. The system contains speed measurement and red light violation. Model has capable of control the speed of cars, control semaphores and configure cameras.
APA, Harvard, Vancouver, ISO, and other styles
9

Sardinha, Anna Luiza Barszczak. "Contribuição para um modelo de circulação do LCR na cabeça." Master's thesis, FCT - UNL, 2008. http://hdl.handle.net/10362/2292.

Full text
Abstract:
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Biomédica
A circulação do líquido cefaloraquidiano (LCR) é de extrema importância para a compreensão de patologias importantes como a Hidrocefalia de Pressão Normal(HPN), que é causada por um desequilíbrio entre a produção e a absorção do LCR. É portanto fundamental o desenvolvimento de um modelo que abranja todo o sistema do LCR de maneira a melhorar o conhecimento do sistema e permitir tratamentos mais eficazes. A quantificação de parâmetros de fluxo de LCR medidos no aqueduto de Sylvius tem sido utilizada para indicar se o paciente sofre de HPN. Há quem defenda que valores de fluxo total (FT) superiores a 18 ml/min indicam HPN, há quem defenda que valores de volume bidireccional médio (VBM) superiores a 42 μl justificam a terapia por derivação ventricular, levando a potenciais diagnósticos contraditórios. Neste estudo pretendemos contribuir para um modelo de circulação do LCR acrescentando dados obtidos na charneira da base do crânio, para estudarmos a dinâmica de circulação no interior da caixa craniana. Como se assume que o LCR seja produzido principalmente no plexo coroideu dos ventrículos laterais e absorvido nas granulações aracnoideias, podemos verificar a quantidade de LCR que flui dentro do cérebro entre o terceiro e quarto ventrículos, no aqueduto de Sylvius, e a quantidade de LCR que flui para o espaço subaracnoideu craniano e raquidiano na charneira da base do crânio, verificando o comportamento dinâmico dos parâmetros de circulação e da onda de propagação de fluxo, controlada pelo fluxo sanguíneo que entra no crânio. Estes exames quantitativos foram obtidos com a técnica de contraste de fase, PC-MRI por Ressonância Magnética que permite uma quantificação do fluxo durante um ciclo cardíaco in vivo e sem perturbação do sistema. Verificamos que tanto o VBM como o FT diminuem com o aumento do ritmo cardíaco, diminuindo mais drasticamente o VBM do que o FT e que o pico da sistole e da diástole se aproximam com esse aumento cardíaco. Foram feitas duas medições em regiões de interesse diferentes para a charneira da base do crânio devido à dificuldade de rodear o espaço subaracnoideu exteriormente e interiormente. O resultado para a medição em redor do espaço subaracnoideu mostrou-se mais concordante com os valores adquiridos no aqueduto de Sylvius. Verificamos também que os parâmetros de circulação estão correlacionados com a área do aqueduto de Sylvius, necessitando esta relação de ser mais aprofundada em estudos futuros.
APA, Harvard, Vancouver, ISO, and other styles
10

Bathelt, Regina Ehlers. "Ensaios para um modo de ler modelos didático-teóricos em educação matemática : um estudo sobre a ótica do modelo dos campos semânticos /." Rio Claro, 2018. http://hdl.handle.net/11449/157380.

Full text
Abstract:
Orientador: Romulo Campos Lins
Orientador: Heloisa da Silva
Banca: João Ricardo Viola dos Santos
Banca: Jorge Tarcísio da Rocha Falcão
Banca: Marcus Vinicius Maltempi
Banca: Regina Luzia Corio de Buriasco
Resumo: Este estudo encontra sua justificação no cenário mais amplo de uma pesquisa bibliográfica sobre teorias de educação matemática como as postuladas em Lins, Freudenthal, Davidov, Brosseau, etc., no qual procuramos por desenvolvimento teórico na perspectiva do Modelo dos Campos Semânticos (LINS, 1999, 2004, 2008, 2012), a propósito de gerar meios a caracterizar "ação didática" quando fundamentada em diferentes teorias de educação matemática. A intenção é alcançar dizer de modelo didático a partir do ponto de vista teórico de diferentes constructos de educação matemática. Neste largo cenário, a ideia de caracterizar "ação didática" em diferentes teorias para então oferecer delas uma leitura em paralelo, nos trouxe diante de uma questão central que a precede: a de buscar uma forma de abordar diferença para tecer um contexto em que "ação didática" no escopo de uma teoria não fosse lida por falta no escopo de outra, nem em discursos sobre "melhoria" do ensino de matemática. Este foi o objetivo central desta tese que se caracteriza, então, na produção de um conjunto de ensaios em cuja forma buscamos abordar diferença como experiência necessária e anterior para um modo de ler modelos didático-teóricos e dizer de "ação didática" em educação matemática. Neste intento, a teoria epistemológica do conhecimento elaborada por Romulo Campos Lins, o Modelo dos Campos Semânticos (MCS), comparece tanto como metodologia de pesquisa à produção da forma dos ensaios, quanto como uma das teorias de e... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This study finds its justification in the broader scenario of one bibliographical research on mathematical education theories such as those postulated by Lins, Freudenthal, Davidov, Brosseau, etc. In it, we seek theoretical development from the perspective of the Model of Semantic Fields (LINS, 1999, 2004, 2008, 2012) in order to generate means to characterize "didactical action" when based on different theories of mathematical education. The intention is to talk about a didactical model from theoretical points of view of mathematical education constructs. In this scenario, the idea of characterizing "didactical action" in different theories, to offer from them a parallel reading, brought us to a central question that precedes it. The question is to seek a way of approaching difference to produce a context in which "didactical action", in the scope of one theory, would not be read in the scope of another one through a deficit reading and nor in discourses on "improvement" of mathematics teaching. This was the central aim of this dissertation. It is characterized as a cluster essays production, in which form we search a way of approaching difference as a necessary and previous experience to a mean of reading "didactical action" and saying of didactical models in mathematical education. In this attempt, the epistemological theory of knowledge elaborated by Romulo Campos Lins, the Model of Semantic Fields, appears on one side, as a research methodology to the production of the e... (Complete abstract click electronic access below)
Resumen: Este estudio encuentra su justificación en el escenario más amplio de una investigación bibliográfica sobre teorías de educación matemática como las postuladas en Lins, Freudenthal, Davidov, Brosseau, etc., en el cual buscamos por desarrollo teórico en la perspectiva del Modelo de los Campos Semánticos (LINS, 1999, 2004, 2008, 2012), a propósito de generar medios para caracterizar "acción didáctica" cuando está fundamentada en diferentes teorías de educación matemática. La intención es llegar a decir de modelo didáctico desde el punto de vista teórico de diferentes constructos de educación matemática. En este escenario, la idea de caracterizar "acción didáctica" en diferentes teorías para entonces ofrecer de ellas una lectura en paralelo, nos trajo ante una cuestión central que la precede: la de buscar una forma de abordar diferencia para tejer un contexto en que "acción "didáctica" en el alcance de una teoría no fuera leída por falta en el ámbito de otra, ni en discursos sobre "mejora" de la enseñanza de matemáticas. Este fue el objetivo central de esta tesis que se caracteriza entonces, en la producción de un conjunto de ensayos en cuya forma busco abordar diferencia como experiencia necesaria y anterior para un modo de leer "acción didáctica" y decir de modelos didácticos en educación matemática. En este intento, la teoría epistemológica del conocimiento elaborada por Romulo Campos Lins, el Modelo de los Campos Semánticos (MCS), aparece tanto como metodología de investigac... (Resumen completo clicar acceso eletrônico abajo)
Doutor
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "LWR models"

1

Banks, H. Thomas. Approximation methods for control of acoustic/structure models with piezoceramic actuators. Hampton, Va: Institute for Computer Applications in Science and Engineering, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Die Deliktsfähigkeit juristischer Personen: Eine rechtsvergleichende Untersuchung zur Übertragbarkeit des englischen Modells. Frankfurt: P. Lang, 2001.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Martins, Marta. Ler Sophia: Os valores, os modelos e as estratégias discursivas nos contos de Sophia de Mello Breyner Andresen. Portugal: Porto Editora, 1995.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Lucile, Bas, Hilbring Meike, Rey Francine, Öğdül Rahmi, and Özgüner Işıl, eds. Gettyimages 1910'lar: Fotoğraflarla 20. yüzyılın sosyal tarihi = Decades of the 20th century = Decennies du XX siecle. İstanbul: Literatür Yayıncılık, 2005.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Nascimento, Aires Augusto. Ler contra o tempo: Condições dos textos na cultura portuguesa (recolha de estudos em Hora de Vésperas). Lisboa: Centro de Estudos Clássicos, 2012.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

France. Commissariat à l'énergie atomique., ed. Proceedings of the seminar on thermal performance of high burn-up LWR fuel: 3-6 March 1998, Commissariat à lÉnergie Atomique (CEA) Cadarache, France. Paris: Nuclear Energy Agency, Organisation for Economic Co-operation and Development, 1998.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Effective Classroom Management: Models and Strategies for Today's Classrooms. Prentice Hall, 2003.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Hardin, Carlette J. Effective Classroom Management: Models and Strategies for Today's Classrooms. Prentice Hall, 2003.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Manning, M. Lee, and Katherine T. Bucher. Classroom Management: Models, Applications, and Cases. Prentice Hall, 2002.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Manning, M. Lee, and Katherine T. Bucher. Classroom Management: Models, Applications, and Cases. Prentice Hall, 2002.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "LWR models"

1

Garavello, Mauro, and Benedetto Piccoli. "A Multibuffer Model for LWR Road Networks." In Complex Networks and Dynamic Systems, 143–61. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-6243-9_6.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Ludovic, L., C. Estelle, and L. Jorge. "The Lagrangian Coordinates Applied to the LWR Model." In Hyperbolic Problems: Theory, Numerics, Applications, 671–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-75712-2_67.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Jingbo, Wang, Qian Li, and Wang Jingtao. "Study of Dynamic Traffic Flow Network Model Based on LWR Model." In Communications in Computer and Information Science, 562–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-34038-3_77.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Leclercq, Ludovic, and Jorge A. Laval. "A Multiclass Car-Following Rule Based on the LWR Model." In Traffic and Granular Flow ’07, 151–60. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-77074-9_13.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Kita, Kenji, Takeshi Kawabata, and Hiroaki Saito. "GLR Parsing in Hidden Markov Model." In Generalized LR Parsing, 153–64. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-4034-2_11.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Forcadel, Nicolas, and Mamdouh Zaydan. "Derivation of a Macroscopic LWR Model from a Microscopic follow-the-leader Model by Homogenization." In IFIP Advances in Information and Communication Technology, 272–81. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-55795-3_25.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Flynn, Robin J. "CD95 and the MRL-lpr Mouse Model." In Methods in Molecular Biology, 219–28. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-6780-3_21.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Guthier, C. V., K. P. Aschenbrenner, F. Wenz, and J. W. Hesser. "Compressed Sensing-Based LDR Brachytherapy Inverse Treatment Planning with Biological Models." In IFMBE Proceedings, 421–24. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19387-8_102.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Chen, Jianzhong, Zhongke Shi, and Yanmei Hu. "Numerical Solution of a Two-Class LWR Traffic Flow Model by High-Resolution Central-Upwind Scheme." In Computational Science – ICCS 2007, 17–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-72584-8_3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Agrawal, Shweta, Daniel Wichs, and Shota Yamada. "Optimal Broadcast Encryption from LWE and Pairings in the Standard Model." In Theory of Cryptography, 149–78. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-64375-1_6.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "LWR models"

1

Humphries, Larry, Brad Beeny, David Louie, Hossein Esmaili, and Michael Salay. "Non-LWR Model Development for the MELCOR Code." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-82415.

Full text
Abstract:
MELCOR is a fully-integrated, system-level computer code developed by Sandia National Laboratories (SNL) for the Nuclear Regulatory Commission (NRC) with the primary objective of modeling the progression of severe accidents in light water nuclear power plants [1,2,3]. Since the project began in 1982, MELCOR has undergone continuous development to address emerging issues, process new experimental information, and create a repository of knowledge on severe accident phenomena. This paper summarizes model development specifically developed for non-LWR applications such as high temperature gas reactors (HTGR), sodium fast reactors (SFR) and molten salt reactors (MSR). Beginning in 2008, active development work began on HTGR modeling in MELCOR. Models were developed for helium gas thermodynamics, oxidation of graphite, thermal hydraulics and heat transfer for both prismatic and pebble bed designs, cavity cooling systems, fuel failure and fission product release, graphite dust generation, and aerosol transport, deposition, and resuspension. In 2013, work commenced on the development of modeling capabilities for sodium fast reactors. This development included the addition of sodium as a working fluid as well as the addition of models for simulating containment fires (both spray and pool) as well as sodium atmospheric chemistry. Validation of these new models has been completed and code-to-code comparisons with the CONTAIN/LMR code has been performed. Work continues as development of sodium concrete interaction models is now underway. In 2017, work began on adding capabilities for molten salt reactors. A new equation of state for FLIBE coolant has been successfully tested in MELCOR and is now undergoing validation against experiments. The alternate working fluid model has also been extended to permit both water and one alternate condensable working fluid in the same input model.
APA, Harvard, Vancouver, ISO, and other styles
2

Eason, Ernest, and Raj Pathania. "Crack Tip Strain Rate Models for Environmentally-Assisted Fatigue Crack Growth in Light Water Reactor Environments." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63640.

Full text
Abstract:
This paper demonstrates the feasibility of using theoretically-motivated crack tip strain rate (CTSR) models to estimate environmentally-assisted fatigue (EAF) crack growth rate (CGR) in light water reactor (LWR) environments. Four models, each combining one of two CTSR expressions with one of two theoretical derivations from Faraday’s Law, were fitted to measured CGR data under dynamic loadings. The four models were compared with each other and with experimental crack growth data from examples where various austenitic stainless steel base metals and nickel-alloy welds were tested in LWR environments under EAF, periodic partial unloading (PPU) with various hold times, loading gradients with increasing and decreasing stress intensity factor K (±dK/da), and constant K loading. All four models produced good fits to the data on some examples, and the models using the newer derivation performed well on all examples. Default model parameters and an equation for the distance from the crack tip at which strain rate is estimated were successful in simplifying the application of the models. Both variable effects and measured CGR were well modeled. Advantages and issues of theoretically-based CTSR models are presented.
APA, Harvard, Vancouver, ISO, and other styles
3

Higuchi, Makoto, Kazuya Tsutsumi, and Katsumi Sakaguchi. "Evaluation of Fatigue Damage in LWR Water With and Without Threshold and Moderation Factor." In ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-1774.

Full text
Abstract:
During the past twenty years, the fatigue initiation life of LWR structural materials, carbon, low alloy and stainless steels has been shown to decrease remarkably in the simulated LWR (light water reactor) coolant environments. Several models for evaluating the effects of environment on fatigue life reduction have been developed based on published environmental fatigue data. Initially, based on Japanese fatigue data, Higuchi and Iida proposed a model for evaluating such effects quantitatively for carbon and low alloy steels in 1991. Thereafter, Chopra et al. proposed other models for carbon, low alloy and stainless steels by adding American fatigue data in 1993. Mehta developed a new model which features the threshold concept and moderation factor in Chopra’s model in 1995. All these models have undergone various revisions. In Japan, the MITI (Ministry of International Trade and Industry) guideline on environmental fatigue life reduction for carbon, low alloy and stainless steels was issued in September 2000, for evaluating of aged light water reactor power plants. The MITI guideline provide equations for calculations applicable only to stainless steel in PWR water and consequently Higuchi et al. proposed in 2002 a revised model for stainless steel which incorporates new equations for evaluation of environmental fatigue reduction in BWR water. The paper compares the latest versions of these models and discusses the conservativeness of the models by comparison of the models with available test data.
APA, Harvard, Vancouver, ISO, and other styles
4

Chopra, Omesh K., and William J. Shack. "The Effect of LWR Coolant Environments on the Fatigue Life of Reactor Materials." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93889.

Full text
Abstract:
The existing fatigue strain–vs.–life (ε–N) data illustrate potentially significant effects of light water reactor (LWR) coolant environments on the fatigue resistance of pressure vessel and piping steels. This paper reviews the existing fatigue ε–N data for carbon and low–alloy steels and austenitic stainless steels in LWR coolant environments. The effects of key material, loading, and environmental parameters, such as steel type, strain amplitude, strain rate, temperature, dissolved oxygen level in water, flow rate, surface finish, and heat-to-heat variation, on the fatigue lives of these steels are summarized. An updated version of the ANL statistical models is presented for estimating the fatigue ε–N curves for these steels as a function of the material, loading, and environmental parameters. The Fen (environmental fatigue correction factor) approach for incorporating the effects of LWR coolant environments into the fatigue evaluations of the American Society of Mechanical Engineers Code is presented.
APA, Harvard, Vancouver, ISO, and other styles
5

Chopra, Omesh K. "Development of a Fatigue Design Curve for Austenitic Stainless Steels in LWR Environments: A Review." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1229.

Full text
Abstract:
The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components and specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain–vs.–life (ε–N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This paper reviews the existing fatigue ε–N data for austenitic stainless steels in LWR coolant environments. The effects of key material, loading, and environmental parameters, such as steel type, strain amplitude, strain rate, temperature, dissolved oxygen level in water, and flow rate, on the fatigue lives of these steels are summarized. Statistical models are presented for estimating the fatigue ε–N curves for austenitic stainless steels as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are presented. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue design curves.
APA, Harvard, Vancouver, ISO, and other styles
6

Humphries, Larry L., Brad J. Merrill, and David L. Louie. "Integration of CONTAIN Liquid Metal Models Into the MELCOR Code." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30288.

Full text
Abstract:
A sodium coolant accident analysis code is necessary to provide regulators with a means of performing confirmatory analyses for future sodium reactor licensing submissions. MELCOR and CONTAIN, which are currently employed by the U.S. Nuclear Regulatory Commission (NRC) for light water reactor (LWR) licensing, have been traditionally used for level 2 and level 3 probabilistic analyses as well as containment design basis accident analysis. To meet future regulatory needs, new models will be added to the MELCOR code for simulation of Liquid Metal Reactor (LMR) designs. Existing models developed for separate effects codes will be integrated into the MELCOR architecture. This work integrates those CONTAIN code capabilities that feasibly fit within the MELCOR code architecture. Implementation of such models for sodium reactor simulation into an actively maintained, full-featured, integrated severe accident code fills a significant gap in capability for providing the necessary analysis tools for regulatory licensing. Current work scope will focus on the following implementation goals: • Phase 1: Implement sodium Equations of State (EOS) as a working fluid for a MELCOR calculation from: ○ The fusion safety database ○ The SIMMER-III Code ○ The SAS4a Code • Phase 2: Examine and test changes to the CONTAIN-LMR Implemented by Japan Atomic Energy Agency, specifically: ○ Aerosol Condensation ○ Implementation of the capability for simultaneous sodium and water condensation modeling • Phase 3: Implementation and Validation of CONTAIN physics models: ○ Sodium Spray Fires (including new test data) ○ Sodium Pool Modeling ○ Sodium Pool Fires • Phase 4: Implementation and Validation of CONTAIN chemistry models: ○ Debris Bed/Concrete Cavity Interactions ○ Sodium Pool Chemistry ○ Atmospheric Chemistry An option for changing the EOS for the MELCOR working fluid from water to liquid metal and the heat transfer from water/steam to liquid metal has been implemented into MELCOR. The property models implemented include an analytic EOS model developed for the SIMMER-III code and the fusion safety works done at Idaho National Laboratory (INL). This paper provides a summary of the status of the code development work. A description of the current models implemented together with user requirements and test calculations will be presented.
APA, Harvard, Vancouver, ISO, and other styles
7

Chopra, O. K., and W. J. Shack. "Margins for ASME Code Fatigue Design Curve: Effects of Surface Finish and Material Variability." In ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-1772.

Full text
Abstract:
The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. This Code specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life (ε-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of the existing fatigue ε-N data for carbon and low-alloy steels and wrought and cast austenitic SSs to define the effects of key material, loading, and environmental parameters on the fatigue lives of the steels. Experimental data are presented on the effects of surface roughness on the fatigue life of these steels in air and LWR environments. Statistical models are presented for estimating the fatigue ε-N curves as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are discussed. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue evaluations. A critical review of the margins for the ASME Code fatigue design curve is presented.
APA, Harvard, Vancouver, ISO, and other styles
8

Higuchi, Makoto, and Katsumi Sakaguchi. "Review and Consideration of Unsettled Problems on Evaluation of Fatigue Damage in LWR Water." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71306.

Full text
Abstract:
Reduction in the fatigue life reduction of structural materials of nuclear components in LWR water was initially detected and examined by the authors in the 1980s, who subsequently directed considerable effort to the development of a method for evaluating this reduction quantitatively. Following the establishment of equations to calculate environmental fatigue life reduction for carbon and low alloy steels in 1985 by Higuchi and Sakamoto [1], appeared based on numerous new fatigue data obtained under various environmental and mechanical test conditions. The latest models for evaluation using Fen of the environmental fatigue life correction factor were proposed for carbon and low alloy steels in the year 2000 and for austenitic stainless steel, in 2002. Fen depends on some essential variables such as material, strain rate, temperature, dissolved oxygen and sulfur concentration in steel. The equation for determining Fen is given by each parameter for each material. These models, having been developed three to five years ago, should be properly revised based on new test results. This paper reviews and discusses five major topics pertinent to such revision.
APA, Harvard, Vancouver, ISO, and other styles
9

Langsfeld, Joshua D., Ariyan M. Kabir, Krishnanand N. Kaipa, and Satyandra K. Gupta. "Online Learning of Part Deformation Models in Robotic Cleaning of Compliant Objects." In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8663.

Full text
Abstract:
We present an approach to automatically learn a bimanual robotic cleaning task on compliant objects. One robot grasps the object, while the other robot cleans it. Given a part with unknown deformation characteristics, the system visually detects the regions to be cleaned, and generates plans for both the grasping and cleaning arms. As the system performs cleaning attempts and gains experience with multiple new parts, it learns models of the part deformation depending on the cleaning force and grasping parameters. A planner iteratively generates tool paths for both robots using the available knowledge to optimize the cleaning time, including (1) delays from regrasping a part to minimize deflection and (2) time taken for repeated cleaning attempts over regions that remained dirty. A nonparametric deflection model is learned separately for each part, with minimal assumptions of the material behavior. We demonstrate the approach on a system of two KUKA LWR iiwa robots and a set of thin planar parts. Results indicate that the system is effective at rapidly learning part deformation models to enable effective iterative cleaning performance.
APA, Harvard, Vancouver, ISO, and other styles
10

Tentner, Adrian, Prasad Vegendla, Ananias Tomboulides, Aleks Obabko, Elia Merzari, and Dillon Shaver. "Advances in Modeling Critical Heat Flux in LWR Boiling Flows With the NEK-2P CFD Code." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81910.

Full text
Abstract:
The paper focuses on the extension of the NEK-2P Wall Heat Transfer model, which was initially developed for the analysis of Critical Heat Flux (CHF) under Dryout (DO) conditions to the simulation of CHF under Departure from Nucleate Boiling (DNB) conditions. The paper presents results of recent NEK-2P analyses of several CHF experiments including both DO and DNB conditions. The CHF experiments analyzed have measured the axial distribution of wall temperatures in two-phase boiling flow in a vertical channel with a heated wall. The axial distribution of the calculated wall temperatures is compared with the corresponding experimental data. Reasonably good agreement with measured data is obtained in predicting the CHF location and post CHF wall temperature magnitudes illustrating the ability of the NEK-2P code and Extended Boiling Framework (EBF) models to simulate the CHF phenomena for a wide range of thermal-hydraulic conditions.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "LWR models"

1

Spencer, B. W., and R. J. Gardener. Improved LWR Fuel Rod Mechanics Models. Office of Scientific and Technical Information (OSTI), February 2018. http://dx.doi.org/10.2172/1467423.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Odette, G. Robert, and Takuya Yamamoto. Advanced Models of LWR Pressure Vessel Embrittlement for Low Flux-HighFluence Conditions. Office of Scientific and Technical Information (OSTI), June 2013. http://dx.doi.org/10.2172/1084639.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Odette, G. Robert. High Fluency Low Flux Embrittlement Models of LWR Reactor Pressure Vessel Embrittlement and a Supporting Database from the UCSB ATR-2 Irradiation Experiment. Office of Scientific and Technical Information (OSTI), January 2017. http://dx.doi.org/10.2172/1346148.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Becker, Peter J. Using the Light Weight Deflectometer for Performance-Based Quality Assurance Testing of Cement Modified Subgrades. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317304.

Full text
Abstract:
This report documents the findings from SPR-4230 (Alternative Quality Assurance Methods for Compacted Subgrade). The main objective of SPR-4230 involved establishing performance-related quality assurance (QA) test methods for pavement subgrade construction. Because INDOT generally prefers specifying subgrade treatment type IBC (i.e., 14-in. cement modified subgrade), this study focused on performance-based QA test methods for constructing cement modified subgrade. Moreover, INDOT prefers using light weight deflectometer (LWD) for chemically modified subgrade construction acceptance, so this study aimed to use LWD deflection measurements as performance-related construction acceptance criteria. A laboratory study was performed to relate LWD deflections with resilient modulus that is the key subgrade performance-related parameter in pavement design. In addition, LWD deflections were related with unconfined compressive strength increase that is the key parameter in chemical soil modification mix design. A rigorous field study consisting of LWD testing and falling weight deflectometer (FWD) testing at INDOT new pavement construction sites was conducted to verify the laboratory developed relationship. Recommendations for implementing results of this study into cement modified subgrade construction acceptance is provided, as are recommendations for future research.
APA, Harvard, Vancouver, ISO, and other styles
5

Simunovic, Srdjan, Theodore M. Besmann, and Stewart L. Voit. Benchmark Problem for Calculating Oxygen Potential in High Burnup LWR Fuel using the THERMOCHIMICA Module in Moose/Bison. Office of Scientific and Technical Information (OSTI), September 2014. http://dx.doi.org/10.2172/1163165.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Wadman, Heidi, and Jesse McNinch. Elevation of underlying basement rock, Ogdensburg Harbor, NY. Engineer Research and Development Center (U.S.), June 2021. http://dx.doi.org/10.21079/11681/40843.

Full text
Abstract:
Over six linear miles of shallow acoustic reflection geophysical data were collected in an 800 ft by 300 ft survey region at Ogdensburg Harbor, Ogdensburg, NY. To better accommodate modern commercial vessels and expand the harbor’s capacity, the current navigable depth of -19 ft Low Water Depth (LWD) needs to be increased to -28 ft LWD, and an accurate map of the nature of the riverbed material (e.g., unconsolidated sediment, partially indurated glacial till, or bedrock) is required to effectively plan for removal. A total of 28 boreholes were previously collected to map the stratigraphy, and the effort revealed significant spatial variability in unit thickness and elevation between adjacent boreholes. To accurately map this variable stratigraphy, chirp sub-bottom profiles were collected throughout the region, with an average line spacing of 13 ft. These sub-bottom data, validated and augmented by the borehole data, resulted in high-resolution spatial maps of stratigraphic elevation and thickness for the study area. The data will allow for more accurate assessment of the type and extent of different dredging efforts required to achieve a future uniform depth of -28 ft LWD for the navigable region.
APA, Harvard, Vancouver, ISO, and other styles
7

Heasler, Patrick G. Development of a Random Field Model for Gas Plume Detection in Multiple LWIR Images. Office of Scientific and Technical Information (OSTI), September 2008. http://dx.doi.org/10.2172/1133250.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Weber, M., G. Tartakovsky, C. Farrow, J. Fullerton, J. McDonald, and William Nichols. Vadose Zone Model for LW Crib Area for Composite Analysis. Office of Scientific and Technical Information (OSTI), September 2020. http://dx.doi.org/10.2172/1668816.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Garavaglia, T., and K. Kauffmann. A model for local current decay in a superconducting LR chain. Office of Scientific and Technical Information (OSTI), April 1991. http://dx.doi.org/10.2172/79106.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Park, Sung Soo, Antonio Bobet, and Tommy E. Nantung. Correlation between Resilient Modulus (MR) of Soil, Light Weight Deflectometer (LWD), and Falling Weight Deflectometer (FWD). Purdue University, December 2018. http://dx.doi.org/10.5703/1288284316651.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'LWR models' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography