Correlation Of Material Properties Research Articles

Dual‐Cation Activation of N‐Enriched Porous Carbons Improves Control of CO2 and N2 Adsorption Thermodynamics for Selective CO2 Capture

AbstractPorous carbons have potential to facilitate energy‐efficient separation of CO2 from post‐combustion flue gas. However, the complicated interplay between chemical and textural properties has prevented a comprehensive understanding of selective CO2 adsorption. This study demonstrates how dual cation activation of carbons serves as a synthetic platform to help modulate porosity independent of nitrogen content. For samples derived from nitrogen‐poor precursors, surface areas deviated significantly (2200–4500 m2 g−1) at a constant total nitrogen content (2.3 ± 0.3 at %). Surface area changed less for samples derived from nitrogen‐rich precursors (400–675 m2 g−1 at 23.1 ± 0.1 at % N). Rigorous structure‐function and thermodynamic analysis of these carbons not only helped to uncover the nature of the different adsorption sites, but also established a fundamental linear free energy exchange relationship. This coupled with material property correlations informed the properties that facilitated selective capture of CO2. Critically, for these physisorptive carbons, selectivity is almost entirely a function of relative porosity and chemical adsorbent‐adsorbate interactions play a negligible role.

Enhancing cladding mechanical modelling during DBA/LOCA accidents with FRAPTRAN: The TUmech one-dimensional model

The analysis of the cladding mechanical performance is essential for predicting rod failure during the heat-up phase of a loss-of-coolant accident (LOCA). Previous modelling and simulation exercises have shown that there is room for improvement in the accuracy of fuel performance simulations under such conditions. In this work, TUmech, a simplified standalone version of the mechanical model in TRANSURANUS, has been developed and coupled with FRAPTRAN-2.0. After highlighting the most significant differences between both approaches, particularly in their mechanical treatment and material property correlations, simulations have been performed for IFA-650.2 (fresh fuel) and IFA-650.10 (high burnup fuel) of the Halden LOCA test series. The results obtained from both FRAPTRAN versions have been compared with experimental data and benchmarked against TRANSURANUS estimates, focusing on rod inner gas pressure, post-test cladding outer diameter, and burst time. In both scenarios, FRAPTRAN-TUmech has proven to enhance the accuracy in predicting these three variables compared to the FRAPTRAN default version. However, further validation is required before drawing definitive conclusions based on the encouraging results.

The impact of assumptions on deterministic and probabilistic analyses of earth fill embankments

This paper considers the impact of assumptions made when formulating analytic approaches to deterministic and probabilistic analyses of slope stability. The assumptions reviewed were presented in a paper, Waddell (2023) that presented semi-quantitative stability assessment using survey data, deterministic and probabilistic slope stability analyses of fill embankments constructed from residual soil and weathered bedrock in Western Sydney. A single variable fill strength was adopted, that was obtained from an Infinite Slope analysis assuming fully saturated fill. Rainfall records were used to predict risk of saturation to calculate annual probability of slope failure. The impacts of assumptions used to calculate the strength parameter, factor of safety and predicted failure probability are addressed in this paper. Saturation assumptions, the choice of limit equilibrium model, shape of the probability distribution functions, and spatial correlation of material properties are considered.

A hybrid proper orthogonal decomposition-heteroscedastic sparse Gaussian process regression model for evaluating structural reliability with correlated stochastic material properties

Data-driven material models have shown advantages in recent studies since they can directly use the existing data and improve the model performances further when additional data is available. However, few data-driven material models in the previous studies considered the uncertainty and stochastic correlations of the material properties. In this work, the hybrid Proper Orthogonal Decomposition-Heteroscedastic Sparse Gaussian Process Regression (POD-HSGPR) framework is proposed for predicting stochastic material behaviors and their correlation. The two material behaviors case studies on the metal strength and the rock joint behavior have demonstrated that the proposed POD-HSGPR-based stochastic material model can effectively capture the material properties, material uncertainty, and stochastic correlation between the material behaviors directly from the experimental dataset. The proposed POD-HSGPR model is then applied to a rock slope structure problem to investigate the influence of the correlation of material properties on structural behavior. The results indicate that the proposed POD-HSGPR model could effectively quantify the correlation effect in a non-parametric format and avoid the overestimation of structural reliability.

Cortical bone relationships are maintained regardless of sex and diet in a large population of LGXSM advanced intercross mice

IntroductionKnowledge of bone structure-function relationships in mice has been based on relatively small sample sets that limit generalizability. We sought to investigate structure-function relationships of long bones from a large population of genetically diverse mice. Therefore, we analyzed previously published data from the femur and radius of male and female mice from the F34 generation of the Large-by-Small advanced intercross line (LGXSM AI), which have over a two-fold continuous spread of bone and body sizes (Silva et al. 2019 JBMR). MethodsMorphological traits, mechanical properties, and estimated material properties were collected from the femur and radius from 1113 LGXSM AI adult mice (avg. age 25 wks). Males and females fed a low-fat or high-fat diet were evaluated to increase population variation. The data were analyzed using principal component analysis (PCA), Pearson's correlation, and multivariate linear regression. ResultsUsing PCA groupings and hierarchical clustering, we identified a reduced set of traits that span the population variation and are relatively independent of each other. These include three morphometry parameters (cortical area, medullary area, and length), two mechanical properties (ultimate force and post-yield displacement), and one material property (ultimate stress). When comparing traits of the femur to the radius, morphological traits are moderately well correlated (r2: 0.18–0.44) and independent of sex and diet. However, mechanical and material properties are weakly correlated or uncorrelated between the long bones. Ultimate force can be predicted from morphology with moderate accuracy for both long bones independent of variations due to genetics, sex, or diet; however, predictions miss up to 50 % of the variation in the population. Estimated material properties in the femur are moderately to strongly correlated with bone size parameters, while these correlations are very weak in the radius. DiscussionOur results indicate that variation in cortical bone phenotype in the F34 LGXSM AI mouse population can be adequately described by a reduced set of bone traits. These traits include cortical area, medullary area, bone length, ultimate force, post-yield displacement, and ultimate stress. The weak correlation of mechanical and material properties between the femur and radius indicates that the results from routine three-point bending tests of one long bone (e.g., femur) may not be generalizable to another long bone (e.g., radius). Additionally, these properties could not be fully predicted from bone morphology alone, confirming the importance of mechanical testing. Finally, material properties of the femur estimated based on beam theory equations showed a strong dependence on geometry that was not seen in the radius, suggesting that differences in femur size within a study may confound interpretation of estimated material properties.

Effect of uncertainties in geometry, inter-layer boundary and shear strength properties on the probabilistic stability of a 3D embankment slope

ABSTRACT This paper investigates the influence of three forms of uncertainty on the probabilistic stability of an idealised 3D embankment slope. These are: 1D spatial variability in the external geometry of the slope along its length, 2D spatial variability in the depth of the boundary between the embankment material and the foundation layer, and 3D spatial variability in the shear strength properties of the slope and foundation materials. The relative influence of each uncertainty has been investigated using the random finite element method, based on statistics consistent with a Dutch regional dyke. The results indicate that, for such a structure, the soil spatial variability has a much greater influence than uncertainties relating to embankment geometry and inter-layer boundary. In particular, it is demonstrated that the spatial correlation of material properties along the length of the embankment has a greater influence on the probabilistic characteristics of the embankment slope stability and failure consequence than the spatial correlation of properties perpendicular to it. A worst case scale of fluctuation for the material properties is identified.

Experimental and Numerical Studies of the Effect of Microstructure of Ionic Conductors on Generation of Hydrogen in Solid Oxide Electrochemical Cells (SOC)

Ceramic ionic conductors are applied in innovative systems for highly efficient and clean power generation. The oxygen separation membranes and solid oxide fuel cells (SOFC) and solid oxide electrolyzers (SOE) can be the examples.Influence of various structural properties of ceramic ionic conductors which are used for solid oxide fuel cells was well-defined and described using several mathematical models. Such parameters as ionic and electronic conductivity, porosity, tortuosity, shape and distribution of pores were included. In case of solid oxide electrolysis cells, effects of these parameters on the electrolysis reaction remain unclear and obscure. There is no clearly defined correlation, neither there is an optimization tool for modification of the parameters to maximize the performance of solid oxide cell operating in regenerative mode. For that reason it is necessary to perform a complete comprehensive analysis combining both the experimental and numerical techniques to identify the key microstructural parameters and their correlation with the performance of electrochemical reaction. The work was aimed at verification of data presented in earlier studies which advised that porosity of electrodes of SOEs needs to be different than in the case of SOFCs, however different values were claimed. Mingyi et al. [1] indicated that optimum porosity for SOEC is about 45%, however several other studies advised on different values.This paper presents results of numerical simulations and correlation of material properties with operational characteristic of a solid oxide electrochemical cell which were followed by initial experimental investigations towards validation of the numerical model, including the analysis of selected operational states. Model was established on the basis of theoretical correlations between microstructural parameters and macro-level performance. It was used for performing variant analysis of different modes of operation under varied conditions. The outcomes of the numerical investigations made it possible to define the requirements for fabrication of modified cells for high temperature electrolysis which were studied.The work presents preliminary results of electrochemical characterization of modified cells and an attempt to generalize the model of SOC customized to highly efficient electrolysis.The general concept of optimizing the performance of SOE by fine-tuning of the microstructure which was proposed earlier [2] is assessed throughout experiments using in-house 50 mm x 50 mm cells fabricated in the Institute of Power Engineering. The proposed path for tailoring the microstructural properties is presented and discussed.

Creating functionally graded concrete materials with varying 3D printing parameters

ABSTRACT The varying physical property in a functionally graded material can be tailored to its specific requirements while using material resources effectively. 3D concrete printing can produce robust and lightweight functionally graded material for the construction industry. In this study, an approach was developed to create an objective tailored functionally graded concrete material by examining the filament material property correlations with the printing parameters. It was found that the physical property of the printed material is closely correlated to the flow rate and travel speed of the printer. Results obtained from the experiment show that the optimised structure achieved an approximately 50% improvement in the strength-to-weight ratio. This preliminary examination of the 2D optimised concrete structure opens the realm of possibility for future work in 3D optimised functionally graded concrete.

(Invited) Recent Progress in Large Area MOCVD Growth of 2D Materials

Metal-organic chemical vapor deposition (MOCVD) has developed to a mature production technology for state-of-the-art (opto)electronic devices such as LEDs, lasers, solar cells and transistors. Current multi-wafer MOCVD systems allow for scalable processes with precise control of growth parameters ensuring excellent uniformity of deposition rates, dopant concentrations and layer thicknesses. All of these properties are of crucial importance for reproducibly obtaining high-quality ultra-thin films required for next-generation nano-electronic devices. One of the most promising materials for the fabrication of such devices are layered transition-metal dichalcogenides (TMDCs), e.g. molybdenum disulfide (MoS2) or tungsten disulfide (WS2), graphene (Gr) or hBN. Due to their 2D structure, these materials possess unique optical, electrical and magnetic characteristics, and monolayers are considered as material system for several future applications. Moreover, the properties and functionality of a single monolayer can be even further improved by forming heterostructures of several two-dimensional materials. Such complex structures which require control on the atomic level strongly limit the number of available fabrication options, especially for volume production, leaving MOCVD as the most reliable industrial deposition method.In this work, we present wafer-scale MOCVD of high-quality monolayers of MoS2, WS2, hBN and graphene (Gr) on single-crystalline C-plane (0001) sapphire deposited in commercial AIXTRON reactors. Our upscaling effort from 2 inch wafer up to growth on 200 mm wafer supports the industrial demand. Molybdenum hexacarbonyl, tungsten hexacarbonyl and di-tert-butyl sulfide are employed as precursors. By optimizing growth conditions, fully-coalesced MoS2 and WS2 samples without parasitic carbon-related Raman peaks were obtained. XPS analysis indicates only Mo-S and W-S bonds for MoS2 and WS2 samples, respectively, with no indications of any side reactions with either the substrate, impurities or oxygen and demonstrates a high layer quality suitable for research on all kind of devices including advanced transistors and memresistive devices. Samples were characterized using Raman/photoluminescence spectroscopy, SEM and AFM to understand the correlation of growth parameter and material properties. As an example a WS2 growth duration series at 700°C temperature was performed. The intensity ratio of about 2 for the Raman E2g/A1g peaks for the optimized WS2 samples suggests deposition of monolayer WS2 with some admixture of bilayer, as confirmed by AFM. The WS2 monolayer film growth has been successfully upscaled from 2” to 200mm sapphire wafers. hBN thin films have been also grown from borazine precursor both on 2” and 200 mm sapphire substrates. Thickness uniformity of 9 nm hBN films was 3% on 200 mm wafers, as determined by XRR. High-quality monolayer graphene layers grown from CH4/H2 on 2” and 200mm sapphire wafers demonstrated good performance by Raman (2D/G peak ratio >1.5 and low D/G peak ratio (<0.25), as well as low sheet resistance (~1300-1500 Ohm/sq). The grown films had smooth surface morphology with the expected graphene wrinkles visible by AFM). These results demonstrate the applicability of AIXTRON systems for the growth of TMDC, hBN and graphene films on large size substrates. The growth could be easily upscaled from 2” to 200 mm wafer growth with only minor adjustment of the growth parameters. More details on the growth process and material properties as well as results on hBN/Gr, TMDC/Gr and TMDC/hBN heterostructures will be discussed in detail. Figure 1

Water jet guided laser microdrilling of aerospace alloys: Correlation of material properties to process time and quality

The hot section parts in a gas turbine are subject to high working temperatures and mechanical forces. In order to endure the harsh conditions, these parts are generally made of nickel-based superalloys. Furthermore, microholes are drilled on them to help with cooling by allowing the air to pass through. These holes increase the allowable working temperature and service life of the parts as well. Water Jet Guided Laser is a technology that can be conveniently used for microdrilling operations on aerospace jet engine parts. It is a hybrid process, in which a laser beam is coupled with and guided through a thin cylindrical water jet. Pressurized water provides focusing, cooling, and cleaning on the cut region, eliminating undesired side effects of the laser. The technology has many advantages over traditional laser machining, such as consistent focusing, burr-free cutting, minimized tapering, reduced heat affected zone, and recast layer. In this paper, using the Water Jet Guided Laser, variation in process time and quality are studied on different aerospace nickel-based superalloys. The results depend mainly on the thermophysical properties of the processed materials. The experimental results are compared with calculations and correlated to the material properties.

Structural Dynamics in UV Curable Resins Resolved by In Situ 3D Printing X-ray Photon Correlation Spectroscopy

Additive manufacturing (AM) is a promising technique to rapidly produce polymeric materials into complex 3-dimensional (3D) geometries. While AM is widespread and relevant for a range of applications, implementation in industry has outpaced our fundamental understanding of polymer dynamics and structure development during the printing process. Characterization and quantification of such dynamics is necessary to optimize final material properties and design future materials and processes for 3D printing. Here, we utilize X-ray photon correlation spectroscopy (XPCS) to measure spatial and time-resolved, out-of-equilibrium dynamics during direct ink write (DIW) 3D printing. Specifically, we investigate the progression of structural dynamics in a dual cure (UV/thermal) nanocomposite during and directly after printing. As the filament is printed and cured in situ, the relaxation processes of the cross-linking network are measured through the dynamics of inorganic filler particles. The characteristic relaxation time of the dynamics is calculated through the intensity–intensity autocorrelation function g2 and directly correlated to the printing process parameters, such as printhead velocity and UV light intensity. The time-resolved evolution of nanoscale dynamics follows a power-law dependence as the filament is cured. Bulk rheological characterizations reveal the macroscopic solidification of the resin, providing correlation of material properties across a wide range of length and time scales. The measurement of multiscale, out-of-equilibrium dynamics provides insight into the development of structure in polymer nanocomposite filaments during 3D printing and is used to further understand the influence of such parameters on the AM process.

Discrete element modeling for continuous powder feeding operation: Calibration and system analysis.

Research emphases on extensive experimental studies and modeling efforts have been on the rise for the development of accurate predictive models of pharmaceutical unit operations and 'digital-twin' framework for continuous manufacturing lines. These exhaustive studies have been conducted at different process conditions to acquire comprehensive knowledge of effects of process parameters on the overall process dynamics. However, there still lacks a detailed understanding of material property effects of pharmaceutical powders on process operation. To address this issue, a discrete element modeling (DEM) approach combined with material calibration is applied for simulation of feeder unit to obtain particle-level insight into effects of material properties on feeder performance with focus on particle flow and powder mixing within the feeder unit. Bulk calibration is implemented to accurately represent powder material properties within the DEM framework. Different refill situations are simulated using DEM to observe powder mixing, measured at the outlet. Feeder DEM simulations are further applied to understand correlations of material properties on feeder operation. These studies provide a detailed physical insight and particle-scale information into the powder mechanics during powder feeding operation.

Formability Analyses of a Novel Alloy Cold-rolled Batch Annealed Dual Phase Steel

Modelling of batch annealing process parameters of dual phase steels is crucial to obtain targeted steel microstructure, hence desired mechanical properties and enhanced formability. By developing unique annealing profile parameters -including but not limited to critical annealing temperature, isoholding duration and cooling rate- in consideration with chemical composition; high strength steel products possessing better cold formability, strain hardenability and higher anisotropy values are attained. In this study, the correlations of material properties with micro-scale features and processing parameters are investigated. Nakazima tests along with microstructural investigations are performed. Cold-rolled and batch annealed materials of this study are compared with conventionally produced dual phase steels and superior formability is validated through mechanical and microstructural characterization.

The Correlation and Balance of Material Properties for DC Cable Insulation at Design Field

The innovation of materials with disruptive properties can be efficiently guided by improved physical understanding of material design principles. The design of a polymeric insulation depends on the desired requirements of the specific application, which, in the case of DC cable insulation, can be stated in terms of the following properties: controlled electrical conductivity, low space charge accumulation and high breakdown strength. Full characterization and detailed understanding of these properties as well as their correlation and balance may bring the ability to engineer needed dielectric properties for using as DC cable insulation. The aim of this paper is to identify the optimal DC insulation design space and to develop a formalism of the correlation between the conductivity and space charge, guided by a relatively simple model based on two physical parameters, activation energy ($\xi$ ) and mean trap separation ($\lambda$ ). With respect to implications for practical material design, the study demonstrates that a polymer material with activation energies in the range of 0.4 to 0.5 eV with relatively high trap density ($N$ ) ($N= \lambda ^{-3}$ , $\lambda =1$ nm, $N=1\text {E}+27\,\,\text {m}^{-3}$ ) can be suitable for HVDC cable insulation.

Fractional Operators Applied to Geophysical Electromagnetics

SUMMARY A growing body of applied mathematics literature in recent years has focused on the application of fractional calculus to problems of anomalous transport. In these analyses, the anomalous transport (of charge, tracers, fluid, etc.) is presumed attributable to long–range correlations of material properties within an inherently complex, and in some cases self-similar, conducting medium. Rather than considering an exquisitely discretized (and computationally intractable) representation of the medium, the complex and spatially correlated heterogeneity is represented through reformulation of the governing equation for the relevant transport physics such that its coefficients are, instead, smooth but paired with fractional–order space derivatives. Here we apply these concepts to the scalar Helmholtz equation and its use in electromagnetic interrogation of Earth’s interior through the magnetotelluric method. We outline a practical algorithm for solving the Helmholtz equation using spectral methods coupled with finite element discretizations. Execution of this algorithm for the magnetotelluric problem reveals several interesting features observable in field data: long–range correlation of the predicted electromagnetic fields; a power–law relationship between the squared impedance amplitude and squared wavenumber whose slope is a function of the fractional exponent within the governing Helmholtz equation; and, a non–constant apparent resistivity spectrum whose variability arises solely from the fractional exponent. In geologic settings characterized by self–similarity (e.g. fracture systems; thick and richly–textured sedimentary sequences, etc.) we posit that these diagnostics are useful for geologic characterization of features far below the typical resolution limit of electromagnetic methods in geophysics.

Optimisation of laser assisted forming conditions for improved formability of aerospace materials

ISF technology was gradually considered as a manufacturing technology for fabricating sheet metal parts for both commercial and military aircraft. However, many challenges remain with respect to improving the consistency of the process, such as part thinning and springback. This is especially critical for two phase titanium alloy Ti-6AL-4V which has limited formability at room temperature. Therefore, understanding the correlation of laser system parameters and material properties is a key aspect for successful ISF of non-fractured Ti-6AL-4V. The laser heating is modelled to find the relationships between laser power, beam radius, scan speed, and the resultant temperature. The analysis shows that the temperature from laser heating increases with an increase in power, decreases significantly with an increase in beam radius, and decreases slightly with an increase in scan speed.

Mechanical properties of stingray tesserae: High-resolution correlative analysis of mineral density and indentation moduli in tessellated cartilage

Skeletal tissues are built and shaped through complex, interacting active and passive processes. These spatial and temporal variabilities make interpreting growth mechanisms from morphology difficult, particularly in bone, where the remodeling process erases and rewrites local structural records of growth throughout life. In contrast to the majority of bony vertebrates, the elasmobranch fishes (sharks, rays, and their relatives) have skeletons made of cartilage, reinforced by an outer layer of mineralized tiles (tesserae), which are believed to grow only by deposition, without remodeling. We exploit this structural permanence, performing the first fine-scale correlation of structure and material properties in an elasmobranch skeleton. Our characterization across an age series of stingray tesserae allows unique insight into the growth processes and mechanical influences shaping the skeleton. Correlated quantitative backscattered electron imaging (qBEI) and nanoindentation measurements show a positive relationship between mineral density and tissue stiffness/hardness. Although tessellated cartilage as a whole (tesserae plus unmineralized cartilage) is considerably less dense than bone, we demonstrate that tesserae have exceptional local material properties, exceeding those of (mammal) bone and calcified cartilage. We show that the finescale ultrastructures recently described in tesserae have characteristic material properties suggesting distinct mechanical roles and that regions of high mineral density/stiffness in tesserae are confined predominantly to regions expected to bear high loads. In particular, tesseral spokes (laminated structures flanking joints) exhibit particularly high mineral densities and tissue material properties, more akin to teeth than bone or calcified cartilage. We conclude that these spokes toughen tesserae and reinforce points of contact between them. These toughening and reinforcing functions are supported by finite element simulations incorporating our material data. The high stresses predicted for spokes, and evidence we provide that new spoke laminae are deposited according to their local mechanical environment, suggest tessellated cartilage is both mutable and responsive, despite lacking remodeling capability. Statement of SignificanceThe study of vertebrate skeletal materials is heavily biased toward mammal bone, despite evidence that bone and cartilage are extremely diverse. We broaden the perspective on vertebrate skeleton materials and evolution in an investigation of stingray tessellated cartilage, a curious type of unmineralized cartilage with a shell of mineralized tiles (tesserae). Combining high-resolution imaging and material testing, we demonstrate that tesserae have impressive local material properties for a vertebrate skeletal tissue, arguing for unique tissue organization relative to mammalian calcified cartilage and bone. Incorporating our materials data into mechanical models, we show that finescale material arrangements allow this cartilage to act as a functional and responsive alternative to bone, despite lacking bone’s ability to remodel. These results are relevant to a diversity of researchers, from skeletal, developmental, and evolutionary biologists, to materials scientists interested in high-performance, low-density composites.

Correlated Materials Characterization via Multimodal Chemical and Functional Imaging.

Multimodal chemical imaging simultaneously offers high-resolution chemical and physical information with nanoscale and, in select cases, atomic resolution. By coupling modalities that collect physical and chemical information, we can address scientific problems in biological systems, battery and fuel cell research, catalysis, pharmaceuticals, photovoltaics, medicine, and many others. The combined systems enable the local correlation of material properties with chemical makeup, making fundamental questions of how chemistry and structure drive functionality approachable. In this Review, we present recent progress and offer a perspective for chemical imaging used to characterize a variety of samples by a number of platforms. Specifically, we present cases of infrared and Raman spectroscopies combined with scanning probe microscopy; optical microscopy and mass spectrometry; nonlinear optical microscopy; and, finally, ion, electron, and probe microscopies with mass spectrometry. We also discuss the challenges associated with the use of data originated by the combinatorial hardware, analysis, and machine learning as well as processing tools necessary for the interpretation of multidimensional data acquired from multimodal studies.

Exploring indicators for fatigue cracking in hot mix asphalt pavements using simplified-viscoelastic continuum damage theory

Fatigue cracking in asphalt pavements results in decreased ride quality, decreased fuel economy, and provides an avenue for intrusion of water. Since the current asphalt mixture design relies primarily on proportioning of component materials, performance is not considered directly. An advancement in technology is to design through direct material property assessment and correlations to field performance, a performance-based mixture design. The objectives of this paper are to: (1) relate mixture stiffness, fatigue, and pavement system characteristics together for use in the performance-based mixture design; (2) identify a Simplified-Viscoelastic Continuum Damage (S-VECD) model output parameter which produces the most separation between poorly and satisfactorily performing structures when combined with dynamic modulus and phase angle information; and (3) evaluate the impact of reclaimed asphalt pavement on the performance of the indicator. A pavement response model was coupled with the S-VECD analysis to determine the fatigue life using a representative pavement structure. Results show a relationship exists between the fatigue life of the pavement system, the dynamic modulus and phase angle, as well as an energy-based index. This approach holds promise because of its reliance on material attributes that can be derived on one testing machine. The model parameters from dynamic modulus and direct tension cyclic fatigue testing can also be incorporated into performance prediction software, further enhancing the appeal of a performance specification using the approach described in this study.

Extending the reactivity initiated accident (RIA) fuel performance code SCANAIR for boiling water reactor (BWR) applications

In this paper, capabilities of the SCANAIR transient fuel performance code are evaluated and extended for boiling water reactor (BWR) fuel low temperature cladding failure predictions and high temperature thermal hydraulics modelling. The SCANAIR code, developed by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN), is designed for modelling the behaviour of a single fuel rod during reactivity initiated accident (RIA) in a pressurized water reactor (PWR). In a previous study (Arffman et al., 2012), new BWR cladding material property correlations were developed and implemented into SCANAIR. Here, SCANAIR’s ability to predict BWR cladding failures due to pellet-cladding-mechanical interaction (PCMI) is evaluated by modelling the NSRR FK test series. SCANAIR is found to give correct predictions with reasonably good accuracy when applied to a larger dataset of several tests. As the standard thermal hydraulics model in SCANAIR is one-dimensional and able to model single phase coolant only, the simulation of a BWR RIA, the control rod drop accident, is not possible when the bulk boiling regime is reached. In this study, the code’s application field is broadened to consider bulk boiling in BWRs. In the chosen approach, SCANAIR is coupled with an external thermal hydraulics code. For that, VTT’s in-house general thermal hydraulics code GENFLO has been used. The first demonstration simulations show promising results.