A Comparison Between Recent Advances in Cylindrical Nodal Diffusion Methods

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
David V. Colameco ◽  
Kostadin N. Ivanov ◽  
Rian H. Prinsloo ◽  
Djordje I. Tomasevic ◽  
Suzanne Theron
Keyword(s):  
Finite Difference ◽  
Expansion Method ◽  
State University ◽  
Nodal Method ◽  
Industry Standard ◽  
Significant Performance ◽  
And Performance ◽  
Nodal Diffusion ◽  
Comparative Results ◽  
Nodal Methods

The resurgence of high temperature reactor (HTR) technology has prompted the development and application of modern calculation methodologies, many of which are already utilized in the existing power reactor industry, to HTR designs. To this end, the use of nodal diffusion methods for full core neutronic analysis is once again considered for both their performance and accuracy advantages. Recently a number of different approaches to two-dimensional and 3D multigroup cylindrical nodal diffusion methods were proposed by various institutions for use in HTR and, specifically, pebble-bed modular reactor (PBMR) calculations. In this regard, we may mention the NEM code from the Pennsylvania State University based on the nodal expansion method and the OSCAR-4 code from NECSA, utilizing a conformal mapping approach to the analytic nodal method. In this work we will compare these two approaches in terms of accuracy and performance. Representative problems, selected to test the methods thoroughly, were devised and based on both a modified version of the PBMR 400 MW benchmark problem and a “cylindrisized” version of the IAEA two-group problem. The comparative results between OSCAR-4 and NEM are given, focusing on global reactivity estimation, as well as power and flux errors as compared with reference finite-difference solutions. These results indicate that both OSCAR-4 and NEM recover the global reference solution for the IAEA problem and show power errors, which are generally acceptable for nodal methods. For the PBMR problem the accuracy is similar, but some convergence difficulties are experienced at the outer boundaries of the system due to the very large dimensions of the reflector (when compared with typical water-moderated reactors). For both codes a significant performance increase was found, as compared with finite-difference calculations, which is the method currently employed by the PBMR (Pty) Ltd. In conclusion it seems that nodal methods have potential for use in the HTR analysis and, specifically, the PBMR calculational arena, although cylindrical geometry based nodal methods will have to develop toward maturity before becoming the industry standard.

A Comparison Between Recent Advances in Cylindrical Nodal Diffusion Methods

2008 ◽  
Author(s):  
David V. Colameco ◽  
Kostadin N. Ivanov ◽  
Rian H. Prinsloo ◽  
Djordje I. Tomasevic ◽  
Suzanne Theron
Keyword(s):  
Finite Difference ◽  
Expansion Method ◽  
State University ◽  
Nodal Method ◽  
Industry Standard ◽  
Significant Performance ◽  
And Performance ◽  
Nodal Diffusion ◽  
Comparative Results ◽  
Nodal Methods

The resurgence of High Temperature Reactor (HTR) technology has prompted the development and application of modern calculation methodologies, many of which are already utilized in the existing power reactor industry, to HTR designs. To this end, the use of nodal diffusion methods for full core neutronic analysis is once again considered for both their performance and accuracy advantages. Recently a number of different approaches to Two-Dimensional (2D) and 3D multigroup cylindrical nodal diffusion methods were proposed by various institutions for use in HTR, and specifically Pebble Bed Modular Reactor (PBMR), reactor calculations. In this regard we may mention the NEM code from the Pennsylvania State University (PSU), based on the Nodal Expansion Method; and the OSCAR code from NECSA, utilizing a conformal mapping approach to the Analytic Nodal Method. In this work we will compare these two approaches in terms of accuracy and performance. Representative problems, selected to test the methods thoroughly, were devised and based on both a modified version of the PBMR 400 MW benchmark problem and a “cylindrisized” version of the IAEA two-group problem. The comparative results between OSCAR and NEM are given, focusing on global reactivity estimation, as well as power and flux errors as compared to reference finite-difference solutions. These results indicate that both OSCAR and NEM recover the global reference solution for the IAEA problem, and show power errors which are generally acceptable for nodal methods. For the PBMR problem the accuracy is similar, but some convergence difficulties are experienced at the outer boundaries of the system due to the very large dimensions of the reflector (when compared to typical water-moderated reactors). For both codes a significant performance increase was found as compared to finite-difference calculations, which is the method currently employed by the PBMR (Pty) Ltd company. In conclusion it seems that nodal methods have potential for use in the HTR analysis, and specifically PBMR calculational arena, although cylindrical geometry based nodal methods will have to develop toward maturity before becoming the industry standard.

scholarly journals Good practices for the translation, cultural adaptation, and linguistic validation of clinician-reported outcome, observer-reported outcome, and performance outcome measures

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Shawn McKown ◽  
Catherine Acquadro ◽  
Caroline Anfray ◽  
Benjamin Arnold ◽  
Sonya Eremenco ◽  
...  
Keyword(s):  
Cultural Adaptation ◽  
Patient Reported Outcome ◽  
Validation Process ◽  
Linguistic Validation ◽  
Performance Outcome ◽  
Industry Standard ◽  
Patient Reported ◽  
And Performance ◽  
Clinical Outcome Assessments ◽  
Translation And Cultural Adaptation

Abstract Within current literature and practice, the category of patient-reported outcome (PRO) measures has been expanded into the broader category of clinical outcome assessments (COAs), which includes the subcategory of PRO, as well as clinician-reported outcome (ClinRO), observer-reported outcome (ObsRO), and performance outcome (PerfO) measure subcategories. However, despite this conceptual expansion, recommendations associated with translation, cultural adaptation, and linguistic validation of COAs remain focused on PRO measures, which has created a gap in specific process recommendations for the remaining types. This lack of recommendations has led to inconsistent approaches being implemented, leading to uncertainty in the scientific community regarding suitable methods. To address this gap, the ISOQOL Translation and Cultural Adaptation Special Interest Group (TCA-SIG) has developed recommendations specific to each of the three COA types currently lacking such documentation to support a standardized approach to their translation, cultural adaptation, and linguistic validation. The recommended process utilized to translate ObsRO, ClinRO and PerfO measures from one language to another aligns closely with the industry standard process for PRO measures. The substantial differences between respondent categories across COA types require targeted approaches to the cognitive interviewing procedures utilized within the linguistic validation process, including the use of patients for patient-facing text in ClinRO measures, and the need to interview the targeted observers for ObsROs measures.

Fuzzy System for DOA Estimation of Coherent Signals

2013 ◽  
Vol 427-429 ◽  
pp. 575-581
Author(s):  
Ya Ling Chen ◽  
Chien Chou Lin
Keyword(s):  
Fuzzy System ◽  
High Performance ◽  
Expert Knowledge ◽  
Doa Estimation ◽  
Coherent Signals ◽  
Fuzzy Logic Systems ◽  
Significant Performance ◽  
And Performance ◽  
Low Sensitivity ◽  
Resolution Estimation

This paper presents an efficient direction-of-arrival (DOA) Estimator for dealing with coherent signals. The empirical results show that significant performance degradation occurs when coherent signals coexist. Therefore, an utilizes the low sensitivity of Bartlett algorithm in estimation of DOAs for coherent signals to yield a low-resolution estimation of DOAs as initial search angle and uses fuzzy logic systems with incorporating expert knowledge to improve the resolution and performance of estimation of DOAs in coherent signals environment. Finally, numerical example was analyzed to illustrate high performance of the proposed method and to confirm the designed procedure.

scholarly journals Cross-Mode Comparability of Computer-Based Testing (CBT) Versus Paper-Pencil Based Testing (PPT): An Investigation of Testing Administration Mode among Iranian Intermediate EFL Learners

2017 ◽  
Vol 10 (2) ◽  
pp. 23 ◽  
Author(s):  
Hooshang Khoshsima ◽  
Monirosadat Hosseini ◽  
Seyyed Morteza Hashemi Toroujeni
Keyword(s):  
Undergraduate Students ◽  
Pearson Correlation ◽  
Language Assessment ◽  
State University ◽  
Pearson Correlation Test ◽  
Computer Based ◽  
Computer Based Testing ◽  
Testing Mode ◽  
And Performance ◽  
And Gender

Advent of technology has caused growing interest in using computers to convert conventional paper and pencil-based testing (Henceforth PPT) into Computer-based testing (Henceforth CBT) in the field of education during last decades. This constant promulgation of computers to reshape the conventional tests into computerized format permeated the language assessment field in recent years. But, enjoying advantages of computers in language assessment raise the concerns of the effects that computerized mode of testing may have on CBT performance. Thus, this study investigated the score comparability of Vocabulary in Use test taken by 30 Iranian undergraduate students studying at a state university located in Chabahar region of Iran (CMU) to see whether scores from two administrations of testing mode were different. Therefore, two similar tests were administered to the male and female participants on two testing mode occasions with four weeks interval. Employing One-Way ANOVA statistical test to compare the mean scores and Pearson Correlation test to find the relationship between mode preference and performance revealed that two sets of scores were not different and gender difference was not also considered a variable that might affect performance on CBT. Based on the results, computerized version of the test can be considered a favorable alternative for the state undergraduate students in Iran.

scholarly journals Design of meteorological intelligent sensor based on POE Technology

2021 ◽  
Vol 2121 (1) ◽  
pp. 012016
Author(s):  
Qiangjun Liu ◽  
Yun Liang ◽  
Junlin Zhang ◽  
Liangbo Qi
Keyword(s):  
Power Supply ◽  
Power Supply System ◽  
Supply System ◽  
Actual System ◽  
Intelligent Sensor ◽  
Industry Standard ◽  
Working Principle ◽  
Supply Industry ◽  
And Performance ◽  
System Power

Abstract An application scheme of Poe based Ethernet technology in meteorological intelligent sensor system is designed. The working principle and implementation method of Ethernet power supply system (POE) based on IEEE802.3af Ethernet power supply industry standard are experimentally analyzed. The power supply part of the meteorological intelligent sensor makes full use of Poe technology to provide current on the network cable transmitting data, which greatly reduces the complexity of the power supply system and improves the reliability of the system power supply design. Through the test of the actual system, the function and performance of the meteorological intelligent transmission system have achieved the expected results.

scholarly journals The Determinant Factors Affecting the Employee Performance Improvement of Educational Institution, State Institution and State-owned Enterprise

2018 ◽  
Vol 1 (2) ◽  
pp. 116
Author(s):  
Ana Sriekaningsih ◽  
Mariman Darto ◽  
Agus Subekti
Keyword(s):  
Organizational Citizenship ◽  
Work Motivation ◽  
Employee Performance ◽  
Educational Institution ◽  
State Institution ◽  
The State ◽  
State University ◽  
Factors Affecting ◽  
East Kalimantan ◽  
And Performance

<p><em>This study focuses on the factors that affect the employee performance in terms of institutions where they work. </em><em>There are three objects or locations that become the research focus, namely educational institutions represented by the state university in East Kalimantan, government institutions represented by the State AdministrationInstitution (LAN) and state-owned institutions represented by PT. Pupuk Kaltim Tbk. The research results show that employee performance is influenced by three factors, namely competence, work motivation, and organizational culture.The performance of government employees is influenced by three factors, namely religiosity, organizational culture, and organizational citizenship behaviors (OCB).</em><em> </em><em>And performance of state-owned employees is influenced only by work motivation.</em><em></em></p>

Depletion Calculation for a Nodal Reactor Physics Code

2010 ◽  
Author(s):  
Antonio Carlos Marques Alvim ◽  
Fernando Carvalho da Silva ◽  
Aquilino Senra Martinez
Keyword(s):  
Diffusion Equation ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Expansion Method ◽  
Design System ◽  
Pressurized Water Reactor ◽  
Reactor Physics ◽  
Pressurized Water ◽  
Nodal Method ◽  
Orthogonal Polynomial Expansion

This paper deals with an alternative numerical method for calculating depletion and production chains of the main isotopes found in a pressurized water reactor. It is based on the use of the exponentiation procedure coupled to orthogonal polynomial expansion to compute the transition matrix associated with the solution of the differential equations describing isotope concentrations in the nuclear reactor. Actually, the method was implemented in an automated nuclear reactor core design system that uses a quick and accurate 3D nodal method, the Nodal Expansion Method (NEM), aiming at solving the diffusion equation describing the spatial neutron distribution in the reactor. This computational system, besides solving the diffusion equation, also solves the depletion equations governing the gradual changes in material compositions of the core due to fuel depletion. The depletion calculation is the most time-consuming aspect of the nuclear reactor design code, and has to be done in a very precise way in order to obtain a correct evaluation of the economic performance of the nuclear reactor. In this sense, the proposed method was applied to estimate the critical boron concentration at the end of the cycle. Results were compared to measured values and confirm the effectiveness of the method for practical purposes.

Significant Performance Improvement with MPD in HPHT Narrow Drilling Window Campaign in the North Sea

2021 ◽  
Author(s):  
Babar Kamal ◽  
Abdul Saboor ◽  
Graeme MacFarlane ◽  
Frank Kernche
Keyword(s):  
Precise Determination ◽  
Lessons Learned ◽  
Overburden Pressure ◽  
The North ◽  
Fracture Pressure ◽  
Open Hole ◽  
Infill Drilling ◽  
Significant Performance ◽  
And Performance ◽  
Formation Pore Pressure

Abstract Significant depletion in reservoir pressure, huge uncertainties in pore and fracture pressure, high overburden pressure on top of reservoir, Narrow Mud Weight Window (NMWW) and Partial/Total losses whilst entering the reservoir made these HPHT (High Pressure High Temperature) wells conventionally un-drillable. Due to these substantial challenges these wells were considered not only costly but also carry a high probability of failure to reach well TD (Total Depth). MPD (Managed Pressure Drilling) is a safer and more effective drilling technique as compared to conventional drilling, especially in wells with NMWW and downhole hazards. The precise determination and dynamic downhole pressure management was imperative to complete these wells without well control incidents. The Constant Bottom Hole Pressure (CBHP) variant in combination of automated MPD system was deployed with a mud weight statically underbalanced while dynamically managed above formation pore pressure to minimize the overbalance across the open hole. MPD enabled the operator to efficiently navigate Equivalent Circulation Density (ECD) through the pore and fracture pressure window, allowed significant improvements throughout the entire campaign. This paper discusses the challenges faced during the last three wells drilled in the campaign which includes equipment issues, commissioning delays, losses whilst drilling, Managed Pressure Cementing (MPC), 7" drill-in-liner and plugged/blocked lines due to weather and mud conditions. The paper describes HPHT infill drilling experience, specific techniques, practices as well as lessons learned from each well during the campaign were implemented to address challenges and to improve performance. The MPD system commissioning was optimized by repositioning the lines which saved significant critical rig time. The blowdown points were added on the lines that were not operational continuously therefore a procedure was developed for flushing to avoid plugging. Optimized drilling strategy was also developed where MW was further reduced to avoid losses as observed in previous wells and CBHP was maintained by manipulating Surface Back Pressure (SBP) from surface. This paper also discusses continuous improvements /upgrades in MPD operating software which assisted the operator in accurate monitoring of flow, SBP and BH-ECD to save significant rig cost in terms of invisible Non-Productive Time (NPT). MPD is a drilling enabler and performance enhancer which saved 80 days of Authorization for Expenditure (AFE) on this challenging HPHT campaign.

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