Updated Boundary Research Articles

Assessing and harnessing updated polyketide synthase modules through combinatorial engineering

The modular nature of polyketide assembly lines and the significance of their products make them prime targets for combinatorial engineering. The recently updated module boundary has been successful for engineering short synthases, yet larger synthases constructed using the updated boundary have not been investigated. Here we describe our design and implementation of a BioBricks-like platform to rapidly construct 5 triketide, 25 tetraketide, and 125 pentaketide synthases to test every module combination of the pikromycin synthase. Anticipated products are detected from 60% of the triketide synthases, 32% of the tetraketide synthases, and 6.4% of the pentaketide synthases. We determine ketosynthase gatekeeping and module-skipping are the principal impediments to obtaining functional synthases. The platform is also employed to construct active hybrid synthases by incorporating modules from the erythromycin, spinosyn, and rapamycin assembly lines. The relaxed gatekeeping of a ketosynthase in the rapamycin synthase is especially encouraging in the quest to produce designer polyketides.

Prediction of transport in the JET DTE2 discharges with TGLF and NEO models using the TGYRO transport code

The JET Deuterium-Tritium-Experiment Campaign 2 (DTE2) has demonstrated the highest-ever fusion energy production. To forecast the transport dynamics within these discharges, the TGLF and NEO models within the TGYRO transport code were employed. A critical development in this study is the new quasilinear transport model, TGLF-SAT2, specifically designed to resolve discrepancies identified in JET deuterium discharges. This model accurately describes the saturated three-dimensional (3D) fluctuation spectrum, aligning closely with a database of nonlinear CGYRO turbulence simulations, thereby enhancing the predictive accuracy of TGYRO simulations. In validating against the JET DTE2 discharges across two primary operating scenarios, TGYRO effectively predicted the temperature profiles within a broad radial window (ρ ∼ 0.2–0.85), though with minor ion temperature discrepancies near the core. However, a consistent underprediction of electron density profiles by 20% across the simulation domain was noted, indicating areas for future refinement. To achieve a self-consistent steady-state solution based on the JET DTE2 discharges, an integrated modeling workflow TGYRO-STEP within the OMFIT framework was introduced. This workflow iterates among the core transport, the pedestal pressure and the MHD equilibrium, ultimately yielding a converged solution that significantly reduces dependence on experimental boundary conditions for temperature and density profiles. The integrated simulation results show negligible differences in electron density and temperature profiles compared to standalone TGYRO modeling, while the ion temperature profile is lower due to the updated boundary condition in TGYRO-STEP. The application of the TGYRO-STEP workflow to JET DTE2 discharges serves as a crucial test to validate its robustness and highlights its limitations, providing valuable insights for its potential future application in ITER and Fusion Power Plant deuterium and tritium prediction modeling.

Flow over traveling and rotating cylinders using a hybrid Eulerian–Lagrangian solver

Hybrid Eulerian–Lagrangian solvers have gained increasing attention in the field of external aerodynamics, particularly when dealing with strong body–vortex interactions. This approach effectively combines the strengths of the Eulerian component, which accurately resolves boundary layer phenomena, and the Lagrangian component, which efficiently evolves the wake downstream. This study builds on our team’s previous work by enhancing the capabilities of a two-dimensional hybrid Eulerian–Lagrangian solver. We aim to upgrade our solver which was initially designed for static cases, to now also simulate cases involving moving objects. To ensure the reliability and applicability of a new solver, it is essential to validate its performance in complex cases. Here, the solver is validated across the case of a traveling cylinder and the case of a rotating cylinder in two different rotational speeds at low Reynolds numbers. In the realm of Eulerian solvers, such as OpenFOAM (utilized for the Eulerian component of this hybrid approach), traditional techniques include the use of morphing meshes, overset meshes, and Arbitrary Mesh Interfaces (AMI) to model body motion. The proposed methodology involves extending the Eulerian mesh up to a short distance from the solid boundary and moving it entirely as a solid entity. Then the Lagrangian solver is responsible for calculating the updated boundary conditions, thereby completing the hybrid solver’s functionality. This approach is very similar to the overset mesh technique. However, unlike the traditional method where an Eulerian mesh moves on top of a static one, our method involves the motion of an Eulerian mesh over a Lagrangian grid. We compared the results from our hybrid solver with those from a purely Eulerian solver, specifically OpenFOAM. The comparison demonstrates that our solver can replicate OpenFOAM’s results with high accuracy. Another interesting point highlighted in this study is the presence of high-frequency oscillations in the body forces in hybrid solvers that incorporate the redistribution of Lagrangian particles and do not utilize surface elements such as vortex panels, specifically when dealing with dynamic mesh simulations. When the Eulerian mesh travels on top of the Lagrangian grid of particles, the positions of the particles with respect to the Eulerian mesh continuously change. This results in a constant shift of particles near the solid body, where the highest vorticity is observed. Particles that are close to the solid boundary at one time step may find themselves inside the boundary at the next time step, leading to their removal. This pattern continuously changes during the simulation, causing fluctuations in the boundary conditions of the Eulerian solver and manifesting as oscillations in the forces acting on the body. It is shown that this issue can be alleviated either by increasing the spatial resolution of the Lagrangian solver or by synchronizing the movement of the Lagrangian grid with the motion of the Eulerian mesh. The results of the study make the solver trustworthy and pave the way for more demanding external aerodynamic simulations.

Stagnation point flow of third-order nanofluid towards a lubrication surface using hybrid homotopy analysis method

In recent times, the interaction of nanoparticles has significantly enhanced the thermal association of heat transport. This phenomenon plays a crucial role in hydraulic systems, particularly in the context of lubrication and its associated consequences on mass and heat transport. Current studies have focused on investigating the thermal effects of a third-order nanofluid on a lubricated stretched surface near an analytical stagnation point. The lubrication process involves the use of a thin, adjustable coating of lubricant fluid. To analyze this complex system, we employ the Buongiorno model and explore thermophoresis and the Brownian motion phenomenon. For deriving analytical results of updated boundary layer ordinary differential equations, we rely on the dependable and effective hybrid homotopy analysis method (HHAM). To exhibit the effectiveness of our study, we provide a numerical comparison. Based on theoretical flow assumptions, we establish a range of flow parameters. In the presence of lubrication, we physically examine how these parameters affect temperatures, velocities, concentration, and other relevant quantities of thermal interest. These new findings have practical applications in polymer production, heat transmission, and hydraulic systems.

The 2023 US National Seismic Hazard Model: Ground-motion characterization for the conterminous United States

We update the ground-motion characterization for the 2023 National Seismic Hazard Model (NSHM) for the conterminous United States. The update includes the use of new ground-motion models (GMMs) in the Cascadia subduction zone; an adjustment to the central and eastern United States (CEUS) GMMs to reduce misfits with observed data; an updated boundary for the application of GMMs for shallow, crustal earthquakes in active tectonic regions (i.e. western United States (WUS)) and stable continental regions (i.e. CEUS); and the use of improved models for the site response of deep sedimentary basins in the WUS and CEUS. Site response updates include basin models for the California Great Valley and for the Portland and Tualatin basins, Oregon, as well as long-period basin effects from three-dimensional simulations in the Greater Los Angeles region and in the Seattle basin; in the CEUS, we introduce a broadband (0.01- to 10-s period) amplification model for the effects of the passive-margin basins of the Atlantic and Gulf Coastal Plains. In addition, we summarize progress on implementing rupture directivity models into seismic hazard models, although they are not incorporated in the 2023 NSHM. We implement the ground-motion characterization for the 2023 NSHM in the US Geological Survey’s code for probabilistic seismic hazard analysis, nshmp-haz-v2, and present the sensitivity of hazard to these changes. Hazard calculations indicate widespread effects from adjustments to the CEUS GMMs, from the incorporation of Coastal Plain amplification effects, and from the treatment of shallow-basin and out-of-basin sites in the San Francisco Bay Area and Los Angeles region, as well as locally important changes from subduction-zone GMMs, and from updated and new WUS basins.

Estimating water transport in carbon nanotubes: a critical review and inclusion of scale effects.

The quasi-frictionless water flow across graphitic surfaces offers vast opportunities for a wide range of applications from biomedical science to energy. However, the conflicting experimental results impede a clear understanding of the transport mechanism and desired flow control. Existing literature proposes numerous modifications and updated boundary conditions to extend classical hydrodynamic theories for nanoflows, yet a consensus or definitive conclusion remains elusive. This study presents a critical review of the proposed modifications of the pressure driven flow or the Hagen-Poiseuille (HP) equations to estimate the flow enhancement through carbon nanotubes (CNTs). For such a case, we performed (semi-)classical molecular dynamics simulations of water flow in various sizes of CNTs, applied the different forms of boundary definitions from the literature, and derived HP equation models by implementing these modifications. By aggregating seven distinct experimental datasets, we tested various flow enhancement models against our measurements. Our findings indicate that including the interfacial layering-based dynamic slip-definition in the proposed HP equations yields accurate estimations. While considering interfacial viscosity predicts the individual CNT experiments well, using the experimental viscosity yields better estimations of measurements for the water flow enhancement through membranes of CNTs. This critical review testing existing literature demonstrates how to refine continuum fluid mechanics to predict water flow enhancement at the nanoscale providing holistic multiscale modeling.

Level-Set Mass-Conservative Front-Tracking Technique for Multistep Simulations of In-Flight Ice Accretion

This paper presents a novel level-set-based approach to model evolving boundary problems for in-flight ice accretion. No partial differential equations are solved as in the standard level-set formulation, but simple geometrical quantities are employed to provide an implicit discretization of the updated boundary. This method avoids mesh entanglements and grid intersections typical of algebraic and mesh deforming techniques, making it suitable for generating a body-fitted discretization of arbitrarily complex geometries as in-flight ice shapes, including the collision of separate ice fronts. Moreover, this paper presents a local ice thickness correction, which accounts for the body’s curvature, to conserve the prescribed iced mass locally. The verification includes ice accretion over an ellipse and a manufactured example to show the proposed strategy’s advantages and robustness compared to standard algebraic methods. Finally, the method is applied to ice accretion problems. A temporal and grid convergence study is presented for automatic multistep in-flight simulations over a NACA0012 airfoil in rime, glaze, and mixed ice conditions.

Автоматизация выделения границ медицинских участков на примере Санкт-Петербурга

The article describes an approach to the desktop geographic information system application to optimization and (partial) automation of the spatial and non-spatial medical data processing and analysis when estimating the grid of medical lots in an area of medical service, and when forming (considering current morbidity and demographic indicators) updated boundaries of medical lots. Software tools of the QGIS platform were used to process spatial data (QGIS itself and its extension modules, including the GeoMedic module designed with the participation of the authors for medical statistics data geocoding). All medical statistics data used in the study were previously depersonalized in accordance with the requirements of Russian laws. A methodology prototype is elaborated for preparation, analysis, and processing of the data on patients (potential patients) number in the medical service area, together with spatial data (geographical map) of this area. The data of the St. Petersburg city tuberculosis service were used for experimental purposes in the study. Specialists of the St. Petersburg Research Institute of Phthisiopulmonology are involved in the work. Developed methodological toolset prototype ensures partially automated processing of initial data with the formation of boundaries of the medical lots in the analyzed area of medical service. Formation of the boundaries is carried out taking into account the normative number of patients, which must be ensured for the formed lots. The study was performed on the city scale, on the example of St. Petersburg (Russia). Data analysis was performed for the Moskovsky, Petrogradsky, Primorsky and Nevsky Administrative Districts of St. Petersburg. A grid of medical lot boundaries was formed and mapped in the results of the performed analysis. The methodology prototype proposed in the result of the conducted study can be applied in the analysis of existing schemas of medical lots and their updating.

Parallelizable Global Quasi-Conformal Parameterization of Multiply Connected Surfaces via Partial Welding

Conformal and quasi-conformal mappings have widespread applications in imaging science, computer vision and computer graphics, such as surface registration, segmentation, remeshing, and texture map compression. While various conformal and quasi-conformal parameterization methods for simply connected surfaces have been proposed, efficient parameterization methods for multiply connected surfaces are less explored. In this paper, we propose a novel parallelizable algorithm for computing the global conformal and quasi-conformal parameterization of multiply connected surfaces onto a 2D circular domain using variants of the partial welding algorithm and the Koebe's iteration. The main idea is to partition a multiply connected surface into several subdomains and compute the free-boundary conformal or quasi-conformal parameterizations of them respectively, and then apply a variant of the partial welding algorithm to reconstruct the global mapping. We apply the Koebe's iteration together with the geodesic algorithm to the boundary points and welding paths before and after the global welding to transform all the boundaries to circles conformally. After getting all the updated boundary conditions, we obtain the global parameterization of the multiply connected surface by solving the Laplace equation for each subdomain. Using this divide-and-conquer approach, the parameterization of surfaces with very high resolution can be efficiently computed. Experimental results are presented to demonstrate the effectiveness of our proposed algorithms.

A Two-stage Surrogate-Assisted Evolutionary Algorithm (TS-SAEA) for Expensive Multi/Many-objective Optimization

In this paper, a two-stage surrogate-assisted evolutionary algorithm (TS-SAEA) is presented for computationally expensive multi/many-objective optimization, which consists of a convergence stage and a diversity stage. In the convergence stage, the objective space is partitioned into several sub-regions by reference vectors, where the individuals compete with each other. In the diversity stage, the converged individuals and the current non-dominated solutions are combined to form a potential sample set, on which a secondary selection is conducted to further improve the diversity. Specifically, the proposed diversity strategy firstly defines the initial boundary individuals and a candidate pool. The individuals with “max-min angles” will continuously be selected from the pool to supplement the boundary individuals until the number of the boundary individuals equals the number of the current non-dominated solutions. At last, the points with the better space-filling features are picked out from the updated boundary individuals to evaluate the true objectives. The above-mentioned process keeps running until the maximal number of function evaluations is satisfied. To evaluate the performance of TS-SAEA on both low and high-dimensional multi/many-objective problems, it is compared with four state-of-art algorithms on 52 benchmark problems and one engineering application. The experimental results show that TS-SAEA has significant advantages on computationally expensive multi/many-objective optimization problems.

Lamb wave-based damage localization and quantification algorithms for CFRP composite structures

Accurately and quantitatively monitoring the damages in complicated composite structures is very challenging, but essential for assessing their integrity. In this paper, an innovative damage monitoring method based on Lamb wave is proposed for large-scale complicated composite laminates. A combination of a resource-constraint Levenberg-Marquardt algorithm associated with a quantum-inspired gravitational search algorithm is introduced to identify the damage location. A damage contour algorithm using convex envelope of damage reflection points and maximum inscribed n-polygon is developed to determine the quantitative damage size. Meanwhile, a singular loci removal scheme based on an automatically updated boundary region constraint and bivariate normal distribution is utilized to separate the correctly positioned points on the damage periphery from those associated with noise. Experiments on two large-scale composite panels with multiple damage cases are conducted to substantiate the proposed algorithms. Sensor layers with embedded piezoelectric transducer (PZT) sensor networks mounted on the structures are employed to excite and receive Lamb wave signals because of their superiority of flexibility, electrical stability and apt for complex structures. The results demonstrate that the proposed technique is capable of pinpointing both location and size of the damage in the complicated composite structures.

A contemporary view of the ordinary chondrite boot II: Mineralogical variation of S-type asteroids

The ordinary chondrite boot (OC-Boot) is a diagnostic region generated from spectral analyses of the features caused by electron absorptions in the olivine and orthopyroxene of OCs. In our companion article to this one, McClure & Lindsay (2022a) demonstrated that the boundaries of the OC-Boot are band parameter analysis (BPA) dependent. Here, we highlight how using OC-Boot boundaries that are not derived from a self-consistent BPA analysis can lead to potential misidentification of ordinary chondrite-like asteroid analogs. We compare S-type asteroid spectral band parameters to the OC-Boot defined in McClure & Lindsay (2022a) and the OC-Boot defined in Gaffey et al. (1993). We choose the Gaffey et al. (1993) OC-Boot for this comparison since its use is frequently seen in the literature without updated boundaries. By applying the Spectral Analysis Routine for Asteroids (SARA) to spectra from the MIT-Hawaii Near-Earth Object Spectroscopic (MITHNEOS) Survey, we demonstrate an overlap between the contemporary view of the OC-Boot and OC analogs, showing that a self-consistent OC-Boot framework captures the variation of the Near-Earth asteroids (NEAs) more than the original OC-Boot. In particular, we show the OC-Boots from McClure & Lindsay (2022a) encompass relatively more NEAs. We also apply a set of calibration equations derived using SARA to determine the mineral abundances and compositions for the S-type asteroids. We find that 59.57% of NEAs exhibit LL-like mineralogies and that H-like and L-like mineralogies are exhibited 19.15% and 6.38% of cases, respectively. There are a couple of cases wherein the mineralogies could be in between subtypes and five cases where no subtype designation could be determined. The high-frequency of LL-like mineralogies is in agreement with previous studies on S-type NEAs.

The Effects of Metallicity on Convective Overshoot Behavior in Models of δ Scuti Variable Stars

Abstract δ Scuti variables are stars which exhibit periodic changes in their luminosity through radial and nonradial pulsations. Internally, these stars have relatively small convective cores, and convective overshoot can significantly affect the size. Recently, models of radial pulsation in δ Scuti stars found a strong correlation between the pulsation constant (Q) as a function of effective temperature and the amount of convective overshoot within the star. However, only models with metallicities of Z = 0.02 were examined, leaving the dependence of` this relationship on chemical composition unknown. In this work, we have extended the model grid to cover a range of metallicities using Modules for Experiments in Stellar Astrophysics (), and analyzed the models’ pulsation properties using GYRE. By varying the models’ mass, rotation speed, convective overshoot, and metallicity, we studied the behavior of Q at low temperature. We found that the updated convective boundary treatment in MESA changes the overshoot dependence found previously, and the value of the slope depends on both rotation and overshoot. We also found that there is a metallicity dependence in the Q values. The lowest metallicity models in our grid reached higher temperatures than previously studied, revealing a parabolic relation between log Q and log T eff .

Reduced El Niño variability in the mid-Pliocene according to the PlioMIP2 ensemble

Abstract. The mid-Pliocene warm period (3.264–3.025 Ma) is the most recent geological period during which atmospheric CO2 levels were similar to recent historical values (∼400 ppm). Several proxy reconstructions for the mid-Pliocene show highly reduced zonal sea surface temperature (SST) gradients in the tropical Pacific Ocean, indicating an El Niño-like mean state. However, past modelling studies do not show these highly reduced gradients. Efforts to understand mid-Pliocene climate dynamics have led to the Pliocene Model Intercomparison Project (PlioMIP). Results from the first phase (PlioMIP1) showed clear El Niño variability (albeit significantly reduced) and did not show the greatly reduced time-mean zonal SST gradient suggested by some of the proxies. In this work, we study El Niño–Southern Oscillation (ENSO) variability in the PlioMIP2 ensemble, which consists of additional global coupled climate models and updated boundary conditions compared to PlioMIP1. We quantify ENSO amplitude, period, spatial structure and “flavour”, as well as the tropical Pacific annual mean state in mid-Pliocene and pre-industrial simulations. Results show a reduced ENSO amplitude in the model-ensemble mean (−24 %) with respect to the pre-industrial, with 15 out of 17 individual models showing such a reduction. Furthermore, the spectral power of this variability considerably decreases in the 3–4-year band. The spatial structure of the dominant empirical orthogonal function shows no particular change in the patterns of tropical Pacific variability in the model-ensemble mean, compared to the pre-industrial. Although the time-mean zonal SST gradient in the equatorial Pacific decreases for 14 out of 17 models (0.2 ∘C reduction in the ensemble mean), there does not seem to be a correlation with the decrease in ENSO amplitude. The models showing the most “El Niño-like” mean state changes show a similar ENSO amplitude to that in the pre-industrial reference, while models showing more “La Niña-like” mean state changes generally show a large reduction in ENSO variability. The PlioMIP2 results show a reasonable agreement with both time-mean proxies indicating a reduced zonal SST gradient and reconstructions indicating a reduced, or similar, ENSO variability.

Finite transformation rigid motion mesh morpher; A grid deformation approach

SummaryIn any shape optimization framework and specifically in the context of computational fluid dynamics, a robust and reliable grid deformation tool is necessary to undertake the adaptation of the computational mesh to the updated boundaries at each optimization cycle. Grid deformation has its share of challenges, namely, to maintain high mesh quality (avoid distorted elements and tangles) even when dealing with extreme deformations. In this work a novel grid deformation algorithm, the finite transformation rigid motion mesh morpher (FT‐R3M) is proposed. FT‐R3M is essentially a mesh‐free grid deformation approach, since it does not require any inertial quantities and it gracefully propagates the movement of the boundaries (surface mesh) to the internal nodes of the mesh (volume mesh), by keeping the motion of its parts (referred to as stencils) as‐rigid‐as‐possible. It is an optimization‐based method, which means that the interior nodes of the computational mesh are displaced to minimize a distortion metric related to the elastic deformation energy, by favoring rigidity in critical directions, thus being able to handle mesh anisotropies very efficiently. Results are presented for three test cases; a rotated airfoil with a mesh appropriate for viscous flow; a simulation of a low Reynolds duct case; a beam.

Boundary Identification and Surface Updates Using MWD

In the banded iron formation-hosted iron ore deposits in the Hamersley Range of Western Australia, the stratigraphic boundaries are generally modelled using data from exploration drilling. Accurately identifying the locations of boundaries is important when modelling and mining ore deposits. Exploration drilling typically has a coarse horizontal spacing (~ 50 m), resulting in inaccuracies in the modelled boundaries on a bench scale. Measure-while-drilling (MWD) data from blast holes has a much denser spacing (~ 5–7 m), and can be used to locally update boundaries with a finer resolution. However, MWD measures the relative effort required to drill through the rock, and this does not directly correlate to the boundaries. Also, MWD measurements can be affected by factors such as blast damage, end-of-hole effects, different equipment, equipment wear, and settings and drill operators. Therefore, an accurate method of identifying the boundary points in the MWD was required. MWD data produces a signal that is significantly different from those in geophysical logs, without areas that can be clearly related to a single rock type, and the data is significantly noisier. Identifying boundary points in the MWD required initial preprocessing and cleaning of the data, including thresholding and applying a continuous wavelet transform. The cleaning allowed a boundary to be more clearly observed visually and reduced the number of incorrect boundary identifications. A Gaussian process (GP) model was trained to successfully identify the transition between the unmineralised West Angelas Shale and mineralised ore. The MWD-based boundary points were then used to train a surface GP to fit the boundary. When boundary points from multiple blasts were used, the GP surface produced a reasonable surface with more detail than the initial, exploration-based surface. Therefore, the GP surface can potentially be used to update geological boundaries in the deposit model to increase their accuracy within localised areas.

Heterogeneous‐decomposition‐based coordinated optimisation for integrated transmission and distribution networks considering communication conditions

An asynchronous heterogeneous decomposition (async-HGD) algorithm for integrated transmission and distribution networks coordinated optimisation considering communication conditions is proposed. Compared with traditional synchronous HGD (sync-HGD), a partial synchronisation mechanism is introduced instead of the full synchronisation to alleviate the influence of communication delays. Under this mechanism, the transmission system operator does not need to wait for the slowest distribution system operator to complete its subproblem and update boundary parameters before the next iteration can proceed. Also, a bounded delay is introduced under this mechanism to ensure sufficient freshness of all the updates. Further, the previous value strategy (PVS) and linear regression strategy (LVS) are applied to handle non-instantaneous interruptions in the communication networks as an improvement of the async-HGD. Numerical experiments show that considering communication delays in the actual operation; the async-HGD takes less time to converge compared with the sync-HGD under appropriate settings. In addition, PVS and LVS can both enhance the robustness of the overall algorithm by achieving approximate solutions, and the LVS can achieve more accurate results compared with the PVS.

Three dimensional numerical modeling using a multi-level nesting system for identifying a Water layer suitable for scallop farming in Tongyeong, Korea

Three-dimensional modeling was performed in Tongyeong, South Korea to identify a space suitable for Yesso scallop farming that may not be successful if seawater temperature remains above 22 °C. In the research area, an underwater basin was found at a depth of 70 m; the depth outside the basin was not deeper than 30 m. It was expected that the water temperature in the interior of the basin might be low enough for farming during summer. The present study was then designed to investigate the temperature distribution in this basin area to verify if a water layer with consistently low temperature existed below the surface layer, using a MOHID (MOdelo HIDrodinámico) three-dimensional numerical model. The model applied mixed vertical coordinates so that the difficulties in modeling near the basin, where water depth sharply changes, could be overcome. In addition, a multi-level nesting system was developed based on the 72 -h forecasting system of the sea status around South Korea, which increased the modeling accuracy using updated boundary conditions. The model was validated by the measured tide and temperature data. The results showed that a strong thermocline was formed at depth of 15 m and a sub-surface space existed at depths deeper than 30 m, where seawater temperature was lower than 22 °C even in summer, which indicates the possibility of successful farming in the research area. The measurements also supported this result because dissolved oxygen and chlorophyll-a were not scarce in the sub-surface space probably due to the strong tidal mixing that could bring the surface seawater properties down below the thermocline. It was also found that the model was effective in resolving the thin thermocline and the sub-surface space below it due to the mixed vertical coordinate system.

PlioMIP2 simulations with NorESM-L and NorESM1-F

Abstract. As a continuation of the Pliocene Model Intercomparison Project (PlioMIP), PlioMIP Phase 2 (PlioMIP2) coordinates a wide selection of different climate model experiments aimed at further improving our understanding of the climate and environments during the late Pliocene with updated boundary conditions. Here we report on PlioMIP2 simulations carried out by the two versions of the Norwegian Earth System Model (NorESM), NorESM-L and NorESM1-F, with updated boundary conditions derived from the Pliocene Research, Interpretation and Synoptic Mapping version 4 (PRISM4). NorESM1-M is the version of NorESM that contributed to the Coupled Model Intercomparison Project Phase 5 (CMIP5). NorESM-L is the low-resolution of NorESM1-M, whereas NorESM1-F is a computationally efficient version of NorESM1-M, with similar resolutions and updated physics. Relative to NorESM1-M, there are notable improvements in simulating the strength of the Atlantic meridional overturning circulation (AMOC) and the distribution of sea ice in NorESM1-F, partly due to the updated ocean physics. The two NorESM versions both produce warmer and wetter Pliocene climate, with a greater warming over land than over ocean. Relative to the preindustrial period, the simulated Pliocene global mean surface air temperature is 2.1 ∘C higher with NorESM-L and 1.7 ∘C higher with NorESM1-F, and the corresponding global mean sea surface temperature enhances by 1.5 and 1.2 ∘C. The simulated precipitation for the Pliocene increases by 0.14 mm d−1 globally in both model versions, with large increases in the tropics and especially in the monsoon regions and only minor changes, or even slight decreases, in subtropical regions. The intertropical convergence zone (ITCZ) shifts northward in the Atlantic and Africa in boreal summer. In the simulated warmer and wetter Pliocene world, AMOC becomes deeper and stronger, with the maximum AMOC levels increasing by ∼9 % (with NorESM-L) and ∼15 % (with NorESM1-F), while the meridional overturning circulation slightly strengthens in the Pacific and Indian oceans. Although the two models produce similar Pliocene climates, they also generate some differences, in particular for the Southern Ocean and the northern middle and high latitudes, which should be investigated through PlioMIP2 in the future. As compared to PlioMIP1, the simulated Pliocene warming with NorESM-L is weaker in PlioMIP2 but otherwise shows very similar responses.

Foundation identification using dynamic strain and acceleration measurements

This paper proposes a method to characterize bridge foundations using live load dynamic strain and acceleration measurements taken from substructure elements during operational loading. These measurements are used to assemble frequency response functions (FRFs) that describe the load-response behavior of the tested foundation element as a function of frequency. This method only requires that a limited number of measurements be performed on the exposed portion of the bridge substructure (piers, columns piles, etc.), and can be performed during daily operational bridge traffic. The direct result of this analysis is an updated boundary condition that be used for modeling of the superstructure in place of the fixed conditions typically used. Furthermore, this method can be used to identify foundation depth and type, verify design parameters, and update finite models of pile and drilled shaft behavior. A case study is presented where dynamic measurements were taken from an in-service drilled shaft.