scholarly journals Sensitivity analysis of critical parameters in board test

1996 ◽  
Vol 13 (1) ◽  
pp. 58-63 ◽  
Author(s):  
M.M.V. Tegethoff ◽  
T.W. Chen
Keyword(s):  
Sensitivity Analysis ◽  
Critical Parameters ◽  
Board Test

Awarding Health: Contracts at the National Institutes of a Sensitivity Analysis of the Critical Parameters

1994 ◽  
Vol 1 (2) ◽  
pp. 117-124
Author(s):  
R. Craig Stotts ◽  
Larry G. Kessler ◽  
John C. Hershey ◽  
Nicholas G. Hall ◽  
Jessie G. Gruman
Keyword(s):  
Sensitivity Analysis ◽  
Critical Parameters

Systematic Parameter Estimation and Sensitivity Analysis Using a Multidimensional PEMFC Model Coupled With DAKOTA

2010 ◽  
Author(s):  
Brian Carnes ◽  
Ken S. Chen ◽  
Fangming Jiang ◽  
Gang Luo ◽  
Chao-Yang Wang
Keyword(s):  
Sensitivity Analysis ◽  
Parameter Estimation ◽  
Proton Exchange Membrane ◽  
Computational Models ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Critical Parameters ◽  
Model Parameters ◽  
Two Phase ◽  
Manual Adjustment

Current computational models for proton exchange membrane fuel cells (PEMFCs) include a large number of parameters such as boundary conditions, material properties, and numerous parameters used in sub-models for membrane transport, two-phase flow and electrochemistry. In order to successfully use a computational PEMFC model in design and optimization, it is important to identify critical parameters under a wide variety of operating conditions, such as relative humidity, current load, temperature, etc. Moreover, when experimental data is available in the form of polarization curves or local distribution of current and reactant/product species (e.g., O2, H2O concentrations), critical parameters can be estimated in order to enable the model to better fit the data. Sensitivity analysis and parameter estimation are typically performed using manual adjustment of parameters, which is also common in parameter studies. We present work to demonstrate a systematic approach based on using a widely available toolkit developed at Sandia called DAKOTA that supports many kinds of design studies, such as sensitivity analysis as well as optimization and uncertainty quantification. In the present work, we couple a multidimensional PEMFC model (which is being developed, tested and later validated in a joint effort by a team from Penn State Univ. and Sandia National Laboratories) with DAKOTA through the mapping of model parameters to system responses. Using this interface, we demonstrate the efficiency of performing simple parameter studies as well as identifying critical parameters using sensitivity analysis. Finally, we show examples of optimization and parameter estimation using the automated capability in DAKOTA.

scholarly journals An EOQ model for deteriorating items under supplier credits when demand is stock dependent

2010 ◽  
Vol 20 (1) ◽  
pp. 145-156
Author(s):  
Nita Shah ◽  
Poonam Mishra
Keyword(s):  
Sensitivity Analysis ◽  
Optimal Solution ◽  
Deteriorating Items ◽  
Critical Parameters ◽  
Eoq Model ◽  
Constant Rate ◽  
Cash Discount

In many circumstances retailer is not able to settle the account as soon as items are received. In that scenario supplier can offer two promotional schemes namely cash discount and /or a permissible delay to the customer. In this study, an EOQ model is developed when units in inventory deteriorate at a constant rate and demand is stock dependent. The salvage value is associated to deteriorated units. An algorithm is given to find the optimal solution. The sensitivity analysis is carried out to analyze the effect of critical parameters on optimal solution.

The Benefits of Accurate ILI Performance on Pipeline Integrity Programs for Axial Crack and Metal Loss Corrosion Threats

2016 ◽  
Author(s):  
Riski H. Adianto ◽  
Jason B. Skow ◽  
Jeffrey Sutherland
Keyword(s):  
Sensitivity Analysis ◽  
Axial Stress ◽  
Assessment Method ◽  
Critical Parameters ◽  
Metal Loss ◽  
Feature Location ◽  
Depth Measurement ◽  
Axial Crack ◽  
The Impact ◽  
Inspection Performance

An analysis describing the benefits of an accurate in-line inspection (ILI) system performance is presented in this paper. A good ILI performance is characterized as an accurate description of the condition of an inspected pipeline. Information from a better ILI performance, as compared to a poorer one, can be used to reduce the number of required digs and/or extend the re-inspection interval without compromising the pipeline’s integrity. As a result, these parameters can be used to assess the benefits of the improved inspection performance. For this analysis, the ILI performance was represented by the depth sizing accuracy as the depth of a feature is one of the most critical parameters in assessing the pressure containment capacity at the feature location. This work utilized a sensitivity analysis in which the impact of various levels of ILI performance on a pipeline integrity program in terms of the number of required repairs for a given reliability threshold was examined. The number of required repairs associated with each inspection performance was calculated using a reliability based assessment method. This method was selected because it fully accounts for the statistical characteristic of the ILI performance. The sensitivity analysis considered two pipeline condition scenarios for two pipeline systems. The first pipeline condition scenario was characterized as having a high number of features, many of which were severe in size, while the second condition scenario consisted of fewer features that were less significant in size. The analysis was carried out for both axial stress corrosion cracking and metal loss corrosion features. The results of the analysis show that a more accurate ILI depth measurement leads to a more accurate pipeline reliability estimate, and therefore, a reduction in the number of required repairs. However, the benefit associated with continued ILI measurement accuracy improvement exhibits a diminishing trend.

scholarly journals Evaluation of Critical Parameters in Tensile Strength Measurement of Single Fibres

2019 ◽  
Vol 3 (3) ◽  
pp. 69 ◽  
Author(s):  
Faisal Islam ◽  
Sébastien Joannès ◽  
Lucien Laiarinandrasana
Keyword(s):  
Sensitivity Analysis ◽  
Tensile Strength ◽  
Composite Materials ◽  
Measurement Errors ◽  
Single Fibre ◽  
Critical Parameters ◽  
Fibre Strength ◽  
Relative Significance ◽  
Fibre Properties ◽  
Small Gauge

Mechanical properties of fibre reinforced composites are primarily dependent on those of fibres. Fibre properties are used for estimating the damage and strength behaviour of composite materials and structures. Tensile strength of fibres is commonly determined by single fibre tensile tests, which is challenging and is prone to measurement errors. In this study, different possible sources of errors due to experimental limitations in the fibre testing process were identified. Their effect on fibre tensile strength was analytically modelled. This model was used to evaluate the uncertainty in experimentally determined fibre strength. A sensitivity analysis was conducted to rank the relative significance of input quantities on the calculated fibre strength. Since composite models require fibre properties determined at very small gauge lengths, the results of the sensitivity analysis were extrapolated to determine critical parameters for tests done at those small gauge lengths of a few millimetres. It was shown that, for sufficiently long fibres, their strength depends mainly on the diameter and failure force; however, for shorter gauge lengths, the effects of misalignment become very significant. The knowledge of uncertainty would be useful in estimating the reliability of the predictions made by composite strength models on the damage and failure behaviour of composite materials and structures. Minimising the influence of critical parameters on fibre strength would help in designing improved single fibre testing systems capable of determining fibre strength more accurately.

scholarly journals 3D Numerical Modelling and Sensitivity Analysis of the Processes Controlling Organic Matter Distribution and Heterogeneity. A Case Study from the Toarcian of the Paris Basin

2018 ◽  
Author(s):  
Benjamin Bruneau ◽  
Marc Villié ◽  
Mathieu Ducros ◽  
Benoit Chauveau ◽  
François Baudin ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Organic Matter ◽  
Primary Productivity ◽  
Critical Parameters ◽  
Strong Impact ◽  
Paris Basin ◽  
Matter Distribution ◽  
Organic Matter Accumulation ◽  
Organic Matter Distribution

The active debate about the processes governing the organic-rich sediment deposition generally involves the relative roles of elevated primary productivity and enhanced preservation related to anoxia. However, other less spotlighted factors could have a strong impact on such deposits: e.g. residence time into the water column (bathymetry), sedimentation rate, transport behavior of organo-mineral floccules on the sea floor. They are all strongly interrelated and may be obscured in the current conceptual models inspired from most representative modern analogues (i.e. upwelling zones and stratified basins). To improve our comprehension of organic matter distribution and heterogeneities, we conducted a sensitivity analysis on the processes involved in organic matter production and preservation which have been simulated within a 3D stratigraphic forward model. The Lower-Middle Toarcian of the Paris Basin was chosen as a case study as it represents one of the best documented example of marine organic matter accumulation. The relative influence of the critical parameters (bathymetry, diffusive transport, oxygen mixing rate and primary production) on the output parameters (Total Organic Carbon, and oxygen level), determined performing a Global Sensitivity Analysis, shows that, in the context of a shallow epicontinental basin, a moderate primary productivity (> 175 gC.m-².yr-1) can led to local anoxia and organic matter accumulation. We argue that, regarding all the processes involved, the presence and distribution of organic-rich intervals is linked as a first-order parameter to the morphology of the basin (e.g. ramp slope, bottom topography). These interpretations are supported by very specific ranges of critical parameters which allowed to obtain output parameter values in accordance with the data. This quantitative approach and its conclusions open new perspectives about the understanding of global distribution and preservation of organic-rich sediments.

scholarly journals Robustness of the Multi-Attribute Utility Model for Bridge Maintenance Planning

2018 ◽  
Vol 13 (4) ◽  
pp. 404-415 ◽  
Author(s):  
Zaharah Allah Bukhsh ◽  
Irina Stipanovic ◽  
Sandra Skaric Palic ◽  
Giel Klanker
Keyword(s):  
Sensitivity Analysis ◽  
Optimal Solution ◽  
Risk Tolerance ◽  
Critical Parameters ◽  
Maintenance Planning ◽  
Bridge Management ◽  
Utility Model ◽  
Attribute Weights ◽  
Multi Attribute Utility Theory ◽  
Decision Making Model

Optimisation of maintenance planning is an essential part of bridge management. With the purpose to support maintenance planning, a multi- objective decision-making model is introduced in this paper. The model is based on multi-attribute utility theory, which is used for the optimisation process when multiple performance goals have to be taken into account. In the model, there are several parameters, which are freely chosen by the decision maker. The model is applied to the inventory of 22 bridges, where four Key Performance Indicators were determined for four performance aspects:  reliability, availability, costs and environment. A sensitivity analysis is performed by changing risk tolerance parameter and attribute weights to determine the robustness of the model. The Multi-Attribute Utility model and sensitivity analysis presented in this paper will help decision-makers to examine the robustness of the optimal solution by dynamically changing the critical parameters.

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