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In the field of computational hemodynamics, sensitivity quantification of pressure and flow wave dynamics has received little attention. This work presents a novel study of the sensitivity of pressure-wave timing and amplitude in the arterial system with respect to arterial stiffness. Arterial pressure and flow waves were simulated with a one-dimensional distributed wave propagation model for compliant arterial networks. Sensitivity analysis of this model was based on a generalized polynomial chaos expansion evaluated by a stochastic collocation method. First-order statistical sensitivity indices were formulated to assess the effect of arterial stiffening on timing and amplitude of the pressure wave and backward-propagating pressure wave in the ascending aorta, at the maximum pressure and inflection point in the systolic phase. Only the stiffness of aortic arteries was found to significantly influence timing and amplitude of the backward-propagating pressure wave, whereas other large arteries in the systemic tree showed marginal impact. Furthermore, the ascending aorta, aortic arch, thoracic aorta, and infrarenal abdominal aorta had the largest influence on amplitude, whereas only the thoracic aorta influenced timing. Our results showed that the non-intrusive polynomial chaos expansion is an efficient method to compute statistical sensitivity measures for wave propagation models. These sensitivities provide new knowledge in the relative importance of arterial stiffness at various locations in the arterial network. Moreover, they will significantly influence clinical data collection and effective composition of the arterial tree for in-silico clinical studies. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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The Mjølnir impact crater in the Norwegian Barents Sea features among the 20 largest impact craters listed in the Earth Impact Database. The impact is dated to 142 ± 2.6 Ma, corresponding closely to the Jurassic/Cretaceous boundary in the Boreal stratigraphy. Multidisciplinary studies carried out over the last three decades have suggested that the up to 40 km wide crater was created by a 1–3 km diameter impactor colliding with a shallow epicontinental sea, causing regional havoc and a regional ecological crisis that followed in its wake. Only minor evidence for the consequences of the impact for the surrounding depositional basins has been documented so far. This study describes a large submarine slump penetrated by hydrocarbon exploration well 7121/9‐1, located in the southern Hammerfest Basin and approximately 350 km away from the impact site. The slump is dated by a black shale drape, which contains characteristic impact‐related biotic assemblages and potential ejecta material. This precise dating enables us to associate the slump with large‐scale fault movements and footwall collapse along the basin‐bounding Troms‐Finnmark Fault Complex, which we conclude were caused by shock waves from the Mjølnir impact and the passage of associated tsunami trains. The draping black shale is interpreted to represent significant reworking of material from the contemporary seabed by tsunamis and currents set up by the impact. [ABSTRACT FROM AUTHOR]

As sediment accumulation indicates basin subsidence, erosion often is understood as tectonic uplift, but the amplitude and timing may be difficult to determine because the sedimentary record is missing. Quantification of erosion therefore requires indirect evidence, for example thermal indicators such as temperature, vitrinite reflectance and fission tracks in apatite. However, as always, the types and quality of data and the choice of models are important to the results. For example, considering only the thermal evolution of the sedimentary section discards the thermal time constant of the lithosphere and essentially ignores the temporal continuity of the thermal structure. Furthermore, the types and density of thermal indicators determine the solution space of deposition and erosion, the quantification of which calls for the use of inverse methods, which can only be successful when all models are mutually consistent. Here, we use integrated basin modelling and Markov Chain Monte Carlo inversion of four deep boreholes to show that the erosional pattern along the Sorgenfrei–Tornquist Zone (STZ) in the eastern North Sea is consistent with a tectonic model of tectonic inversion based on compression and relaxation of an elastic plate. Three wells in close proximity SW of the STZ have different data and exhibit characteristic differences in erosion estimates but are consistent with the formation of a thick chalk sequence, followed by minor Cenozoic erosion during relaxation inversion. The well on the inversion ridge requires ca. 1.7 km Jurassic‐Early Cretaceous sedimentation followed by Late Cretaceous–Palaeocene erosion during inversion. No well demands thick Cenozoic sedimentation followed by equivalent significant Neogene exhumation. When data are of high quality and models are consistent, the thermal indicator method yields significant results with important tectonic and geodynamic implications. [ABSTRACT FROM AUTHOR]

Traits have become a crucial part of ecological and evolutionary sciences, helping researchers understand the function of an organism's morphology, physiology, growth and life history, with effects on fitness, behaviour, interactions with the environment and ecosystem processes. However, measuring, compiling and analysing trait data comes with data‐scientific challenges.We offer 10 (mostly) simple rules, with some detailed extensions, as a guide in making critical decisions that consider the entire life cycle of trait data.This article is particularly motivated by its last rule, that is, to propagate good practice. It has the intention of bringing awareness of how data on the traits of organisms can be collected and managed for reuse by the research community.Trait observations are relevant to a broad interdisciplinary community of field biologists, synthesis ecologists, evolutionary biologists, computer scientists and database managers. We hope these basic guidelines can be useful as a starter for active communication in disseminating such integrative knowledge and in how to make trait data future‐proof. We invite the scientific community to participate in this effort at http://opentraits.org/best‐practices.html. [ABSTRACT FROM AUTHOR]

A two‐dimensional nonlinear numerical model has been developed to study atmospheric coupling due to vertically propagating acoustic gravity waves (AGWs) on different planets. The model is able to simulate both acoustic and gravity waves due to inclusion of compressibility. The model also considers dissipative effects due to viscosity, conduction, and radiative damping. The hyperbolic inviscid advection equations are solved using the Lax‐Wendroff method. The parabolic diffusion terms are solved implicitly using a linear algebra‐based Direct method. The model is validated by comparing numerical solutions against analytical results for linear propagation, critical level absorption, and mountain wave generation over an isolated hill. Acoustic wave generation in Martian atmosphere due to a pressure pulse is also demonstrated. A case study of tsunami‐generated AGWs is presented for the 2004 Sumatra earthquake whereby the model is forced through tsunamigenic sea‐surface displacement. The properties of simulated AGWs closely match those derived from ionospheric sounding observations reported in literature. Another application for Martian ice cloud formation is discussed where gravity waves from topographic sources are shown to create cold pockets with temperatures below the CO2 condensation threshold. The simulated cold pockets coincide with the cloud echo observations from the Mars Orbiting Laser Altimeter aboard Mars Global Survey spacecraft. Plain Language Summary: Gravity waves (GWs) are oscillations in the atmosphere that are responsible for a variety of effects related to disturbances in wind patterns and changes in plasma in the upper atmosphere. These effects are important enough that GWs need to be properly accounted for in the climate models of planets. However, the typical wavelengths of GWs are much smaller than the typical resolutions of these climate models leaving no choice but to use coarse approximations. Several models have been developed independently to perform detailed computer simulations of GWs on different planets, differing in their capabilities and limitations. There is a lack of a general model that can be used to simulate GWs on any planetary atmosphere. Here, we present such a model that can be very useful for performing comparative studies of GWs on different planets. We validate the model by showing agreement between simulations and predictions from theory. We then apply our model to two case studies. The first case shows simulation of GWs from the 2004 Sumatra tsunami. The simulated wave speeds and frequencies match the observations published elsewhere. The second case uses the model to identify regions of orographic CO2 ice cloud formation on Mars. Over 90% of the cloud echo observations are seen to coincide with the cold air pockets simulated by the model. We demonstrate that the presented model can serve as a versatile tool to simulate acoustic gravity waves on different planets. Key Points: A two‐dimensional nonlinear compressible model is presented for simulation of acoustic and gravity waves (AGWs) in different planetary atmospheresThe model is validated, and applied to simulate AGWs generated from the 2004 Sumatra tsunami, and identify CO2 ice cloud regions on MarsThe model is well‐suited to perform comparative studies of gravity wave propagation, growth, and dissipation on different planets [ABSTRACT FROM AUTHOR]

Centrifugal sedimentation, a well‐known solid‐liquid separation process, is typically used for the separation of solids from low concentration feeds because of its high separation efficiency due to high settling velocities. The performance of the tubular bowl centrifuge (TBC) can be studied by using the sigma theory, which assumes plug flow and rigid body motion inside the rotating bowl wall. The separation efficiency of the system is evaluated by determining the effective fluid layer thickness from the experimental data. A method suitable for evaluating the separation efficiency at different parameters for a given TBC is explained along with experimental validation. By using this method, different case studies are performed which depict the influence of each parameter on the separation efficiency. Also, it is demonstrated that the same higher separation efficiency (98 %) at 20 000 rpm could be achieved at higher bowl capacities. [ABSTRACT FROM AUTHOR]

We introduce an approach for the stochastic characterization of the geometric and hydraulic parameters of a three‐dimensional (3D) discrete fracture network (DFN) and for estimating their uncertainty based on data from hydraulic tomography experiments. The inversion approach relies on a Bayesian framework and the resulting posterior distribution is characterized by generating samples by Markov chain Monte Carlo (MCMC) methods. The inversion method is evaluated for four synthetic test cases related to the Grimsel test site in Switzerland. Comparison of original and reconstructed DFN models shows that the presented approach is suitable for identifying variable fracture locations and orientations. This is especially the case for those fractures that represent the preferential flow paths in the simulated experiments. It is also revealed that the Bayesian framework is useful to discriminate fractures based on the reliability of the inversion, which is illustrated by fracture probability maps taken as sections through the studied rock mass. Moreover, it is demonstrated that the hydraulic apertures can be calibrated together with the fracture geometries. A premise for applicability in practice, however, is that the hydraulic measurements are complemented by additional information to sufficiently constrain the value ranges of the geometric and hydraulic parameters to be inverted together. The presented work expands the applicability of a previously presented promising two‐dimensional procedure based on transdimensional inversion to field‐based 3D problems. The theoretical findings here open the door for highly flexible structural characterization in practice based on hydraulic tomography, as well as alternative or complementary tomographic methods. Key Points: We infer the structural properties of a three‐dimensional discrete fracture network given data from hydraulic tomography experimentsThe method is demonstrated for synthetic test cases based on the Grimsel site in SwitzerlandThe inversion yields major geometric parameters and their uncertainties [ABSTRACT FROM AUTHOR]

Fluctuating stream stages and peak‐flow events can significantly influence the interactions between streams and aquifers and modify the hydraulic gradient, the flux exchange and the subsurface flow paths. As a result, stagnation zones and reverse flow may appear in different parts of an aquifer and at different times. These features of the flow field play a relevant role in the transport, transformation, and residence time of solutes, pollutants, and nutrients in the subsurface. However, their identification using numerical models is complex not only because of highly nonlinear dynamics, but also due to significant uncertainties in the model input data which propagate into the quantities of interest. In this work, we use an approach based on polynomial chaos expansions to map the probability of occurrence of stagnation zones and reverse flow during a flood event. We quantify the propagation of uncertainty into the groundwater flow field due to the applied river boundary conditions. Then, we evaluate the responses of the posterior probabilities in an element‐wise fashion using a set of flow classification criteria and kernel density estimations. The proposed methodology is flexible because it employs a nonintrusive pseudo‐spectral technique and, consequently, it can be applied straightforwardly in preexisting models. The regions near the confluence of two streams in the studied area are prone to present transient stagnation and reverse flow. Key Points: The probability of occurrence of stagnation zones and reverse flow is computed based on the uncertainty caused by river boundary conditionsPolynomial chaos expansions are used in an element‐wise fashion for quantifying the propagation of uncertaintyThe regions near the confluence of two streams are very dynamic and prone to the presence of stagnation points and reverse flow [ABSTRACT FROM AUTHOR]

Uncertainty quantification of groundwater (GW) aquifer parameters is critical for efficient management and sustainable extraction of GW resources. These uncertainties are introduced by the data, model, and prior information on the parameters. Here, we develop a Bayesian inversion framework that uses Interferometric Synthetic Aperture Radar (InSAR) surface deformation data to infer the laterally heterogeneous permeability of a transient linear poroelastic model of a confined GW aquifer. The Bayesian solution of this inverse problem takes the form of a posterior probability density of the permeability. Exploring this posterior using classical Markov chain Monte Carlo (MCMC) methods is computationally prohibitive due to the large dimension of the discretized permeability field and the expense of solving the poroelastic forward problem. However, in many partial differential equation (PDE)‐based Bayesian inversion problems, the data are only informative in a few directions in parameter space. For the poroelasticity problem, we prove this property theoretically for a one‐dimensional problem and demonstrate it numerically for a three‐dimensional aquifer model. We design a generalized preconditioned Crank‐Nicolson (gpCN) MCMC method that exploits this intrinsic low dimensionality by using a low‐rank‐based Laplace approximation of the posterior as a proposal, which we build scalably. The feasibility of our approach is demonstrated through a real GW aquifer test in Nevada. The inherently two‐dimensional nature of InSAR surface deformation data informs a sufficient number of modes of the permeability field to allow detection of major structures within the aquifer, significantly reducing the uncertainty in the pressure and the displacement quantities of interest. Key Points: Using Interferometric Synthetic Aperture Radar data reduces the uncertainty in selected quantities of interest compared to using prior knowledge onlyThe preconditioned Crank‐Nicolson (pCN) Markov chain Monte Carlo (MCMC) method is extended to exploit posterior curvature and allow better chain mixingWe demonstrate the intrinsic low dimensionality of the poroelastic inverse problem that is, critical for the success of the MCMC method [ABSTRACT FROM AUTHOR]

In the performance evaluation of power transformers, the occurrence of eddy currents and their effects on the transformer tank have been widely modelled and studied for the cases of power frequency in the steady state. Nonetheless, for the cases when harmonic components are present (zero‐sequence flux) or for transient conditions (inrush or geomagnetically induced current (GIC) events) there is much to do. With this aim, this work presents the proposal in using temporal modelling for evaluating eddy currents in transformer tank walls in practical cases of sinusoidal, harmonic and transient excitations. Obtained results are compared with consolidated commercially available software based on finite elements for showing how good this proposition is. [ABSTRACT FROM AUTHOR]

Characterizing the properties of groundwater aquifers is essential for predicting aquifer response and managing groundwater resources. In this work, we develop a high‐dimensional scalable Bayesian inversion framework governed by a three‐dimensional quasi‐static linear poroelastic model to characterize lateral permeability variations in groundwater aquifers. We determine the maximum a posteriori (MAP) point of the posterior permeability distribution from centimeter‐level surface deformation measurements obtained from Interferometric Synthetic Aperture Radar (InSAR). The scalability of our method to high parameter dimension is achieved through the use of adjoint‐based derivatives, inexact Newton methods to determine the MAP point, and a Matérn class sparse prior precision operator. Together, these guarantee that the MAP point is found at a cost, measured in number of forward/adjoint poroelasticity solves, that is independent of the parameter dimension. We apply our methodology to a test case for a municipal well in Mesquite, Nevada, in which InSAR and GPS surface deformation data are available. We solve problems with up to 320,824 state variable degrees of freedom (DOFs) and 16,896 parameter DOFs. A consistent treatment of noise level is employed so that the aquifer characterization result does not depend on the pixel spacing of surface deformation data. Our results show that the use of InSAR data significantly improves characterization of lateral aquifer heterogeneity, and the InSAR‐based aquifer characterization recovers complex lateral displacement trends observed by independent daily GPS measurements. Key Points: A Bayesian framework was developed for characterizing heterogeneous aquifer properties from surface deformation dataScalable algorithms allow the inference of high‐dimensional discretized parameters in a transient fully coupled 3‐D poroelastic aquifer modelInSAR data significantly improve characterization of lateral aquifer heterogeneity at a test site in Nevada [ABSTRACT FROM AUTHOR]

We present a dynamical model that links through multiple length and time scales the formation of detachment folds, degradation of topography, and deposition of sheet‐like sedimentary bodies in deepwater foldbelt environments based on a nonlinear reaction–diffusion equation. We represent the stratigraphic response predicted by our model in a two‐dimensional parametric space whose axes are given by the Peclet number (Pe), the ratio of the mass transported by tectonic uplift and the mass transferred by diffusive hillslope processes, and the sediment delivery number (Sd), the ratio of sediments transported by density currents to those produced by intrabasinal processes. Notably, we identify three well‐defined regions of sedimentary behavior in that parametric space: a central domain (Pe > 2,Sd > 2) of cyclic stratigraphy produced by self‐sustained oscillations in the sedimentary system and two regions near the graph axes of stable sedimentation in which a continuous stratigraphy is produced. In the central domain, all the mass fluxes are equally important. This creates the conditions for a series of complex interaction between hillslope sediment transport, fold growth, and sedimentation. The other two regions correspond to end‐members in which either the Pe or Sd is small. For small Pe values, topographic degradation and sediment dispersal by hillslope transport dominate over tectonic uplift. Thus, any tectonic perturbation appearing in the system dissipates readily. For small Sd values, sediment transport is dominated by creep, and the system rapidly evolves toward a steady state. Plain Language Summary: Often, the only way to quantify deformation away from plate boundaries is by using sedimentary strata. The idea is that sediments occupy any available space created by deformation, creating a record of the tectonic activity. The basic theory also assumes sedimentation proceeds at steady state. Thus, changes in both energy and materials during sedimentation are necessarily assumed to be either the product of variations in sea level or tectonic events. In this study, we have produced a physics‐based model of folding and sedimentation that incorporates realistic behavior not available in previous models. We focus on deepwater environments since feedbacks between sediment dispersal and fold growth are greatly enhanced in this environment. Our model shows the interpretation of sediments deposited synchronously with tectonism becomes tricky when steady‐state assumptions are cast aside. The model predicts a stable stratigraphy only at low folding and sediment supply rates in which hillslope sediment movement is the predominant form of mass transport. In the second regime, sedimentation becomes unstable even under constant folding rates when the sediment supply and tectonic uplift exceed hillslope transport. This produces a layering composed of a series of cyclic sedimentary deposits produced by self‐reinforced oscillations in the deepwater environment. Key Points: We use a physics‐based model of folding and sedimentation in deepwater environmentsThe model predicts two regimes of autogenic stratigraphic behavior: a stable continuous regime and a pulsatory dynamic regimeModel predictions agree with observations in the deepwater Mexican Ridges foldbelt in the Gulf of Mexico [ABSTRACT FROM AUTHOR]

The locations of wetting front and water table are key variables in an integrated surface‐groundwater modeling. In current land surface models, they are either diagnosed from pressure head profiles or predicted using certain parameterization schemes. Both approaches need to make assumptions on how pressure head changes vertically and numerical results may have large errors when these assumptions are violated. In this work, we propose a numerical framework, which can explicitly track the locations of wetting front and water table. Existing numerical solvers modeling soil water movement usually use water content, pressure head, or both of them as prognostic variables, while in this framework, two additional prognostic variables representing the locations of wetting front and water table are introduced. Besides, another two improvements are explored to make the framework stable and efficient. First, a new equivalent hydraulic conductivity formula accommodating nonlinear hydraulic curves is proposed. The formula is unconditionally stable and can yield oscillation‐free solution of Richards' equation in unsaturated homogeneous soils. Second, a mixed implicit‐explicit temporal discretization is adopted. It uses an implicit scheme initially at every time step to improve the stability and accuracy, while in case of failure in convergence it replaces the iterations with an explicit scheme to guarantee mass conservation. Based on all these improvements, the framework is potentially used to simulate variably saturated flow in stratified soils in land surface models. Seven numerical tests covering various flow situations, boundary conditions, and soil geometries are carried out and illustrate the characteristics of the proposed framework. Key Points: Locations of water table and wetting front are tracked explicitly in solving Richards' equationAn equivalent hydraulic conductivity formula, which can yield oscillation‐free solution of Richards' equation, is proposedA mixed implicit‐explicit temporal discretization is adopted to improve the stability and guarantee mass conservation of water [ABSTRACT FROM AUTHOR]

A closure relation for capillary pressure plays an important role in the formulation of both traditional and evolving models of two‐fluid‐phase flow in porous medium systems. We review the traditional approaches to define capillary pressure, to describe it mathematically, to determine parameters for this relation, and to constrain the domain of applicability of this relation. In contrast to the traditional approach, we provide a rigorous, multiscale definition of capillary pressure, define the state domain of interest in practice, summarize computational and experimental approaches to investigate the system state, and apply the methods for two‐fluid states in a model ink bottle system, the classical Finney pack of spheres, and a synthetic sphere pack system. The results of these applications show that a state equation exists that describes capillary pressure without hysteresis. This state equation parameterizes a function that describes the nonwetting phase volume fraction in terms of the capillary pressure, the interfacial area, and the specific Euler characteristic of the nonwetting phase. Furthermore, this state equation applies over the complete range of conditions encountered in practice, and it applies under both equilibrium and dynamic conditions. This state equation involving capillary pressure forms an important foundation for the development of the next generation of macroscale two‐fluid‐phase flow models in porous medium systems. Key Points: A hysteretic‐free capillary pressure state equation is developedThe state equation is validated using both analytical and numerical simulation approachesThis state equation applies under both equilibrium and dynamic conditions [ABSTRACT FROM AUTHOR]

The Baiyun slide complex contains geological evidence for some of the largest landslide ever discovered in the continental slopes of the South China Sea. High‐resolution seismic data suggest that a variety of landslides with varied scales have occurred repeatedly in this area. The largest landslide reconstructed from bathymetric and seismic data has an estimated spatial coverage of ~5,500 km2 and a conservative volume of ~1,035 km3. Here, using geomorphological and geotechnical data, we construct a series of probable landslide scenarios and assess their tsunamigenic capacity. By treating the slides as deformable mudflows, we simulate the dynamics of landslide movements. The simulated landslide motions match the geophysical observations interpreted in previous studies. Particularly, we are able to reproduce the spatial distribution of observed runout, including the distance, shape, and deposit thickness, for the most credible slide scenario. We investigate tsunami impacts generated by different slide scenarios and highlight the importance of initial water depth, sliding direction, and nearshore bathymetry. The worst‐case scenario is capable of producing basin‐wide tsunami, with maximum wave amplitudes reaching ~5 m near Hong Kong and Macau, 1–3 m in western Philippines, and at least 1 m along central Vietnam, southeast Hainan, and southern Taiwan. The most noticeable phenomenon we observed is that the southern Chinese coast is the hardest‐hit region in all the simulated scenarios regardless of the diverse slide features. We conclude that the persistence of high tsunami impact is caused by the unique bathymetric feature of the wide continental shelf in front of southern China. Plain Language Summary: The tsunami hazard assessment in the South China Sea (SCS) region has been mostly focused on the earthquakes along the Manila Trench in the past, leaving other tsunami sources barely studied. Increasing seafloor exploration has revealed a large number of submarine landslides that are widely distributed in the continental slopes of the SCS. Although less frequent compared with earthquake‐generated tsunamis, the high vulnerability of SCS coastlines demands that we investigate the potential tsunami impacts generated by these submarine landslides. In this study, we assess the tsunamigenic potential of Baiyun landslide, which is characterized by one of the most well‐studied landslides and largest landslides ever discovered in the continental shelf of the SCS. In contrast with previous studies, which use simplified landslide source parameters, we construct six probable slide events with the key slide features inferred from the most updated geophysical data. By treating the landslide movement as deformable mudflows, we find consistency between simulated and observed runout characteristics. The tsunami simulation results suggest that Baiyun landslides have the capacity to generate basin‐wide tsunamis, like its earthquake counterpart from the Manila Trench. The most severely affected coastline is the southern China, which hosts a very high density of coastal cities and major infrastructures. Key Points: Treating Baiyun landslide as translational mudflow allows reproduction of the spatial distribution of observed runoutBaiyun landslide is capable of generating basin‐wide tsunami which would severely affect the coastlines of northern South China SeaSouthern Chinese coast is the hardest‐hit region in all scenarios due to the unique bathymetric feature of the wide continental shelf in front of it [ABSTRACT FROM AUTHOR]

We present a systematic study of the influence on tsunami waves generated by the uplift of a rectangular plug, of the rise time of the deformation, and of its topographic details (e.g., the presence of a sill). We are motivated by the fact that most simulation codes use an instantaneous deformation of a flat ocean floor as an initial condition of the problem, although Hammack (1973, http://resolver.caltech.edu/CaltechAUTHORS:HAMjfm73) performed pioneering laboratory studies as well as analytical computations featuring variable rise times. Here, we consider three 2‐D source shapes, including a flat seafloor, a simple elevated piston, and additional trapezoidal sill on top of it, all with variable rise times, and simulate the resulting waves using the fully nonlinear smooth particle hydrodynamic model graphics processing unit smooth particle hydrodynamic. We validate our results against Hammack's (1973) laboratory measurements and analytical results. We find that a relatively large sill, with height and width of more than half of the local depth and width of the source, has a profound effect on the spatiotemporal structure of the generated free surface wavefield. Specifically, we show that the maximum water surface elevation over the source region is not always the same as the bottom displacement, as assumed in most tsunami propagation models. Next, we obtain simple scaling relationships to predict the maximum height of the generated tsunami over and outside the source, based on the geometry of the sill and the nondimensional bed rise time. Last, we show that inertial effects may lead to an initial free surface displacement over the generation region greater than the maximum vertical displacement of the displaced seabed. Key Points: We use a fully nonlinear and dispersive hydrodynamic model GPUSPH to examine the effects of an uplift of the ocean bottom on the near-field dynamics of earthquake-generated tsunamisWe find that the existence of a sill in the source area with the height and width of more than half of the local depth and width of the source has a profound effect on the generated tsunamiThe significance of the results in the context of realistic seismic and tectonic sources is discussed as well as the implication on tsunami modeling [ABSTRACT FROM AUTHOR]

Forward basin modeling is routinely used in many geological applications, with the critical limitation that chemical diagenetic reactions are often neglected or poorly represented. Here, a new, temperature‐dependent, kinetic diagenesis model is formulated and implemented within a hydromechanical framework. The model simulates the macroscopic effects of diagenesis on (1) porosity loss, (2) sediment strength, (3) sediment stiffness and compressibility, (4) change in elastic properties, (5) increase in tensile strength due to cementation, and (6) overpressure generation. A brief overview of the main diagenetic reactions relevant to basin modeling is presented and the model calibration procedure is demonstrated using published data for the Kimmeridge Clay Formation. The calibrated model is used to show the implications of diagenesis on prediction of overpressure development and structural deformation. The incorporation of diagenesis in a uniaxial burial model results in an increase in overpressure of up to 9 MPa due to both stress‐independent porosity loss and overpressure generated by disequilibrium compaction caused by a reduction in permeability. Finally, a compressional model is used to show that the incorporation of diagenesis within geomechanical models allows the transition from ductile to brittle behavior to be captured due to the increase in strength that results in an overconsolidated stress state. This is illustrated by comparison of the present‐day structures predicted by a geomechanical‐only model, where a ductile fold forms, and a geomechanical model accounting for diagenesis in which a brittle thrust structure is predicted. Key Points: A novel modeling framework is proposed to investigate the macroscopic effects of diagenesis on porosity loss and geomechanical propertiesThe ductile/brittle transition behavior observed in Kimmeridge clay samples is successfully captured by the new modelThe likely impact of diagenesis in overpressure and structural style is demonstrated [ABSTRACT FROM AUTHOR]

A diagnostic geophysical‐based template, supported by modelling, is suggested to be used prior to, or in combination with geological/drilling data, when proposing a marine impact crater. The latter refers to impacts occurring in a marine setting and resulting in structures that are currently partially or totally underwater. The methodology is based on the well‐documented Mjølnir crater in the Barents Sea. The template has been developed in conjunction with the recently proposed and debated impact crater on the Malvinas (Falkland) Plateau in the South Atlantic. Despite their different sizes, their comparison adds to the ambiguous nature of the Malvinas structure and shows that the integrated analysis of seismic and potential field data and modelling is crucial for any interpretation of a marine impact crater without relevant geological information. The proposed workflow template utilizes all available geophysical data and is composed of a series of iterative steps, including a range of alternative nonimpact interpretations that must be discussed and accounted for. Subsequently, further iterative geophysical modelling is required to support and decipher the impact related processes. A more complex impact crater model and additional impact crater features can be resolved by physical property modelling. In all cases, a close spatial correspondence of the defined impact structure with potential field anomalies is a necessity to establish a causal relationship. We suggest that the diagnostic workflow template provides a methodology to be applied to future studies of the Malvinas structure, as well as to proposed marine (and, with minor adaptions, to nonmarine) impact craters in general. [ABSTRACT FROM AUTHOR]

Summary: Ion beam induced heat damage in soft materials and biological samples is not yet well understood in Focused Ion Beam systems (FIBs). The work presented here discusses the physics behind the ion beam – sample interactions and the effects which lead to increases in sample temperature and potential heat damage. A model by which heat damage can be estimated and which allows parameters to be determined that reduce/prevent heat damage was derived from Fourier's law of heat transfer and compared to finite element simulations, numerical modelling results and experiments. The results suggests that ion beam induced heat damage can be prevented/minimised by reducing the ion beam current (local dose rate), decreasing the beam overlap (reduced local ion dose) and by introducing a blur (increased surface cross‐section area, reduced local dose) while sputtering, patterning or imaging soft material and nonresin‐embedded biological samples using FIBs. Lay description: FIB/SEMs, which combine a scanning electron microscope with a focused ion beam in a single device, have found increasing interest biological research. The device allows to cut samples at precisely selected areas and reveal sub surface information as well as preparing transmission electron microscope samples from bulk materials. Preparing biological samples has proven to be challenging due to the induced heat damage. This work explores the physics behind the sample cutting and proposes a model and a method, based on physical principles which allows the user to estimate the induced heat during the cutting process and to select cutting parameters which avoid heat damage in the sample. [ABSTRACT FROM AUTHOR]

Abstract: Applying probabilistic methods to infrequent but devastating natural events is intrinsically challenging. For tsunami analyses, a suite of geophysical assessments should be in principle evaluated because of the different causes generating tsunamis (earthquakes, landslides, volcanic activity, meteorological events, and asteroid impacts) with varying mean recurrence rates. Probabilistic Tsunami Hazard Analyses (PTHAs) are conducted in different areas of the world at global, regional, and local scales with the aim of understanding tsunami hazard to inform tsunami risk reduction activities. PTHAs enhance knowledge of the potential tsunamigenic threat by estimating the probability of exceeding specific levels of tsunami intensity metrics (e.g., run‐up or maximum inundation heights) within a certain period of time (exposure time) at given locations (target sites); these estimates can be summarized in hazard maps or hazard curves. This discussion presents a broad overview of PTHA, including (i) sources and mechanisms of tsunami generation, emphasizing the variety and complexity of the tsunami sources and their generation mechanisms, (ii) developments in modeling the propagation and impact of tsunami waves, and (iii) statistical procedures for tsunami hazard estimates that include the associated epistemic and aleatoric uncertainties. Key elements in understanding the potential tsunami hazard are discussed, in light of the rapid development of PTHA methods during the last decade and the globally distributed applications, including the importance of considering multiple sources, their relative intensities, probabilities of occurrence, and uncertainties in an integrated and consistent probabilistic framework. [ABSTRACT FROM AUTHOR]

Recent developments in synchrotron brilliance and X-ray optics are pushing the flux density in nanofocusing experiments to unprecedented levels, which increases the risk of different types of radiation damage. The effect of X-ray induced sample heating has been investigated using time-resolved and steady-state three-dimensional finite-element modelling of representative nanostructures. Simulations of a semiconductor nanowire indicate that the heat generated by X-ray absorption is efficiently transported within the nanowire, and that the temperature becomes homogeneous after about 5 ns. The most important channel for heat loss is conduction to the substrate, where the heat transfer coefficient and the interfacial area are limiting the heat transport. While convective heat transfer to air is significant, the thermal radiation is negligible. The steady-state average temperature in the nanowire is 8 K above room temperature at the reference parameters. In the absence of heat transfer to the substrate, the temperature increase at the same flux reaches 55 K in air and far beyond the melting temperature in vacuum. Reducing the size of the X-ray focus at constant flux only increases the maximum temperature marginally. These results suggest that the key strategy for reducing the X-ray induced heating is to improve the heat transfer to the surrounding. [ABSTRACT FROM AUTHOR]

Boulders are an important coastal hazard event deposit because they can only be moved by tsunamis and energetic storms effects of storms. Storms and tsunami are competing processes for coastal change along many shorelines. Therefore, distinguishing the boulders that were moved during a storm from those moved by a tsunami is important. In this contribution, we present the results of a parameter study based on the TRIADS model for wave shoaling on mildly sloping beaches, coupled with a boulder-dislodgement model that is based on Newton's Second Law of Motion. The results show how smaller slopes expose the waves longer to the nonlinear processes, thus increasing the energy in the infragravity wave band. More energy in the infragravity wave band means that there are more energy wave lengths that can dislodge larger boulders. At the same time, a steeper slope lowers the threshold for boulder dislodgement (critical angle of dislodgement), making it more likely for larger boulders to be dislodged on a steeper slope. The competition between these two processes govern boulder dislodgement during storms and is investigated inhere. [ABSTRACT FROM AUTHOR]

Empirical studies of agrarian production in developing countries often find that small farms possess a productivity advantage over larger farms. Eswaran and Kotwal (1986) famously derive this inverse farm-size/productivity relationship from the structure of agrarian production. The focal prediction of their model is that, in otherwise equivalent economies, a more egalitarian land distribution raises both output and producer welfare. The traditional (spot) procurement system implicit in the Eswaran and Kotwal model, however, diverges fundamentally from modern (contractual) procurement practices. We therefore develop a new model of agrarian production in order to determine whether the introduction of a modern value chain alters the welfare effects of land redistribution. The inverse farm-size/productivity relationship persists in our model, but we find that more egalitarian land distribution leads to nonmonotonic changes in producer welfare. We also find that the introduction of a modern sector can harm the laboring classes. [ABSTRACT FROM AUTHOR]

Empirical studies of agrarian production in developing countries often find that small farms possess a productivity advantage over larger farms. Eswaran and Kotwal (1986) famously derive this inverse farm-size/productivity relationship from the structure of agrarian production. The focal prediction of their model is that, in otherwise equivalent economies, a more egalitarian land distribution raises both output and producer welfare. The traditional (spot) procurement system implicit in the Eswaran and Kotwal model, however, diverges fundamentally from modern (contractual) procurement practices. We therefore develop a new model of agrarian production in order to determine whether the introduction of a modern value chain alters the welfare effects of land redistribution. The inverse farm-size/productivity relationship persists in our model, but we find that more egalitarian land distribution leads to nonmonotonic changes in producer welfare. We also find that the introduction of a modern sector can harm the laboring classes. [ABSTRACT FROM AUTHOR]

ABSTRACT A gas-solid-liquid three-phase model for the simulation of fiber-reinforced composites mold-filling with phase change is established. The influence of fluid flow on the fibers is described by Newton's law of motion, and the influence of fibers on fluid flow is described by the momentum exchange source term in the model. A revised enthalpy method that can be used for both the melt and air in the mold cavity is proposed to describe the phase change during the mold-filling. The finite-volume method on a non-staggered grid coupled with a level set method for viscoelastic-Newtonian fluid flow is used to solve the model. The 'frozen skin' layers are simulated successfully. Information regarding the fiber transformation and orientation is obtained in the mold-filling process. The results show that fibers in the cavity are divided into five layers during the mold-filling process, which is in accordance with experimental studies. Fibers have disturbance on these physical quantities, and the disturbance increases as the slenderness ratio increases. During mold-filling process with two injection inlets, fiber orientation around the weld line area is in accordance with the experimental results. At the same time, single fiber's trajectory in the cavity, and physical quantities such as velocity, pressure, temperature, and stresses distributions in the cavity at end of mold-filling process are also obtained. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42881. [ABSTRACT FROM AUTHOR]

The finite element method was used to model the moisture movement and strain in the wood supports of panel paintings, in response to changing climate conditions - temperature and relative humidity (RH). The material properties of lime wood ( Tilia sp.), determined experimentally, were used in the modelling. Critical amplitudes of cyclic sinusoidal RH fluctuations generating strain of 0.002 in the most responsive tangential direction of the unrestrained, single wood panel, which the pictorial layer was assumed to endure without damage, were derived for the mid-RH region as a function of cycle duration, panel thickness and diffusion configuration. Panels do not respond significantly to diurnal fluctuations or shorter. The panels respond more and more significantly when the duration of the fluctuations increases until the panel fully responds to each cycle. These fluctuation periods are 14 and 90 days at 20 °C for a panel thickness of 10 and 40 mm, respectively, with two faces of a panel diffusively opened. Sinusoidal RH variations bringing about wood's full response have the critical amplitude of ±6% RH, that is strain of 0.002 endangering the pictorial layer is produced at such amplitude in the tangential direction of the unrestrained panel. [ABSTRACT FROM AUTHOR]

Applications of quantum chemistry have evolved from single or a few calculations to more complicated workflows, in which a series of interrelated computational tasks is performed. In particular multiscale simulations, which combine different levels of accuracy, typically require a large number of individual calculations that depend on each other. Consequently, there is a need to automate such workflows. For this purpose we have developed P YA DF, a scripting framework for quantum chemistry. P YA DF handles all steps necessary in a typical workflow in quantum chemistry and is easily extensible due to its object-oriented implementation in the Python programming language. We give an overview of the capabilities of P YA DF and illustrate its usefulness in quantum-chemical multiscale simulations with a number of examples taken from recent applications. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 [ABSTRACT FROM AUTHOR]

- 40Ar/39Ar dating of potassium feldspar (primary spherulitic-blocky and secondary idiomorphic K-feldspar) separated from impact-metamorphosed gneiss found near Videix in the western central part of the Rochechouart impact structure (NW Massif Central, France) yielded a Rhaetian combined age of 201 ± 2 Ma (2σ), indistinguishable within uncertainty from the age of the Triassic/Jurassic boundary. Ballen quartz intergrown with the primary K-feldspar indicates post-shock temperatures exceeding approximately 1000 °C that affected the precursor gneiss. Geochemically, both feldspar types represent essentially pure potassium end-members. Apart from the approximately 15 km diameter impact deposit area, the youngest crystallization age known for basement rocks in this part of the Massif Central is approximately 300 Ma. No endogenic magmatic-thermal events are known to have occurred later in this region. The K-feldspar recrystallized from local feldspar melts and superimposed post-shock hydrothermal crystallization, probably within some thousands of years after the impact. It is, therefore, suggested that the 40Ar/39Ar age for the Videix gneiss (as a potassic 'impact metasomatite') dates the Rochechouart impact, in consistence with evidence for K-metasomatism in the Rochechouart impactites. The new age value is distinctly younger than the previously obtained Karnian-Norian age for Rochechouart and, thus, contradicts the Late Triassic multiple impact theory postulated some years ago. In agreement with the paleogeographic conditions in the western Tethys domain around the Triassic/Jurassic boundary, the near-coastal to shallow marine Rochechouart impact is compatible with the formation of seismites and tsunami deposits in the latest Triassic of the British Isles and possible related deposits in other parts of Europe. [ABSTRACT FROM AUTHOR]

Space–Time Analysis of Regional Systems (STARS) is an open-source package designed for the dynamic exploratory analysis of data measured for areal units at multiple points in time. STARS consists of four core analytical modules: Anselin (1995) exploratory spatial data analysis; Anselin (2003) inequality measures; Carlino and Mills (1993) mobility metrics; and Christakos, Bogaert, and Serre (2001) spatial Markov. Developed using the Python object-oriented scripting language, STARS lends itself to three main modes of use. Within the context of a command line interface (CLI), STARS can be treated as a package which can be called from within customized scripts for batch-oriented analyses and simulation. Alternatively, a graphical user interface (GUI) integrates most of the analytical modules with a series of dynamic graphical views containing brushing and linking functionality to support the interactive exploration of the spatial, temporal, and distributional dimensions of socioeconomic and physical processes. Finally, the GUI and CLI modes can be combined for use from the Python shell to facilitate interactive programming and access to the many libraries contained within Python. This article provides an overview of the design of STARS, its implementation, functionality, and future plans. A selection of its analytical capabilities are also illustrated that highlight the power and flexibility of the package. [ABSTRACT FROM AUTHOR]

Various variational formulations describing nonstationary compressible fluid flows are considered. In particular, for high-frequency excitations a variationally based approximation frame is deduced which may explain experimentally observed phenomena. [ABSTRACT FROM AUTHOR]

Existing analytical and semianalytical solutions for density‐driven flow (DDF) in porous media are limited to 2‐D domains. In this work, we develop a semianalytical solution using the Fourier Galerkin method to describe DDF induced by salinity gradients in a 3‐D porous enclosure. The solution is constructed by deriving the vector potential form of the governing equations and changing variables to obtain periodic boundary conditions. Solving the 3‐D spectral system of equations can be computationally challenging. To alleviate computations, we develop an efficient approach, based on reducing the number of primary unknowns and simplifying the nonlinear terms, which allows us to simplify and solve the problem using only salt concentration as primary unknown. Test cases dealing with different Rayleigh numbers are solved to analyze the solution and gain physical insight into 3‐D DDF processes. In fact, the solution displays a 3‐D convective cell (actually a vortex) that resembles the quarter of a torus, which would not be possible in 2‐D. Results also show that 3‐D effects become more important at high Rayleigh number. We compare the semianalytical solution to research (Transport of RadioACtive Elements in Subsurface) and industrial (COMSOL Multiphysics®) codes. We show cases (high Raleigh number) where the numerical solution suffers from numerical artifacts, which highlight the worthiness of our semianalytical solution for code verification and benchmarking. In this context, we propose quantitative indicators based on several metrics characterizing the fluid flow and mass transfer processes and we provide open access to the source code of the semianalytical solution and to the corresponding numerical models. Key Points: A 3‐D semianalytical solution for the density‐driven flow model is developed, for the first time, using Fourier series methodThe solution is used to gain physical insight into 3‐D density‐driven flow processes in the case of horizontal crossed density gradientsNumerical simulations, using COMSOL and advanced research code, show the worthiness of the semianalytical solution for benchmarking 3‐D codes [ABSTRACT FROM AUTHOR]