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For today’s demands in underground infrastructure, geotechnical considerations are gaining prominence, emphasizing the resolution of complex problems through numerical modeling and soil-structure interaction analysis. There is a clear trend shifting away from two-dimensional (2-D) plane strain or axisymmetric idealizations to the comprehensive analysis of full three-dimensional (3-D) models. However, despite the inclination towards 3-D modeling of tunnels, establishing a realistic 3-D model for this purpose remains a timeconsuming process. This typically involves multiple iterative and incremental phases, essential for gaining deeper insights into the three-dimensional nature of the problem. Beyond selecting an appropriate constitutive soil model, realistically finite element modeling and accurate simulation of the tunneling process are of paramount importance. This study focuses on the development of a practical full 3-D model and simulation of the Earth Pressure Balance (EPB) shield tunneling process using the finite element code PLAXIS 3D. The numerical model incorporates tunnel boring machine driving data recorded during tunnel construction and is validated through back-analysis of field measurements of tunneling-induced ground surface settlements. The findings demonstrate that numerical simulation can realistically reproduce the main characteristics of EPB shield tunneling. The study recommends adopting non-linear face pressures with depth based on the analysis of tunneling data. Regarding grouting pressure, an effectively linear distributed pressure may be considered, accounting for the grout weight and the increase of soil stresses with depth. This validated numerical framework provides valuable guidance for researchers and practitioners to construct more efficient, reliable, and accurate 3-D models. [ABSTRACT FROM AUTHOR]

Development of chimeric enzymes by protein engineering can more efficiently contribute toward biomass conversion for bioenergy generation. Therefore, prior to experimental validation, a computational approach by modeling and molecular dynamic simulation can assess the structural and functional behavior of chimeric enzymes. In this study, a bifunctional chimera, CtXyn11A-BoGH43A comprising an efficient endoxylanase (CtXyn11A) from Clostridium thermocellum and xylosidase (BoGH43A) from Bacteroides ovatus was computationally designed and its binding and stability analysis with xylooligosaccharides were performed. The modeled chimera showed β-jellyroll fold for CtXyn11A and 5-bladed β-propeller fold for BoGH43A module. Stereo-chemical properties analyzed by Ramachandran plot showed 98.8% residues in allowed region, validating the modeled chimera. The catalytic residues identified by multiple sequence alignment were Glu94 and Glu184 for CtXyn11A and Asp229 and Glu384 for BoGH43A modules. CtXyn11A followed retaining-type, whereas BoGH43A enforced inverting-type of reaction mechanism during xylan hydrolysis as revealed by superposition and GH11 and GH43 familial analyses. Molecular docking studies showed binding energy, (ΔG) − 4.54 and − 4.18 kcal/mol for CtXyn11A and BoGH43A modules of chimera, respectively, with xylobiose, while − 3.94 and − 3.82 kcal/mol for CtXyn11A and BoGH43A modules of chimera, respectively, with xylotriose. MD simulation of CtXyn11A-BoGH43A complexed with xylobiose and xylotriose till 100 ns displayed stability by RMSD, compactness by Rg and conformational stability by SASA analyses. The lowered values of RMSF in active-site residues, Glu94, Glu184, Asp229, Asp335 and Glu384 confirmed the efficient binding of chimera with xylobiose and xylotriose. These results were in agreement with the earlier experimental studies on CtXyn11A releasing xylooligosaccharides from xylan and BoGH43A releasing d-xylose from xylooligosaccharides and xylobiose. The chimera showed stronger affinity in terms of total short-range interaction energy; − 190 and − 121 kJ/mol for with xylobiose and xylotriose, respectively. The bifunctional chimera, CtXyn11A-BoGH43A showed stability and integrity with xylobiose and xylotriose. The designed chimera can be constructed and applied for efficient biomass conversion. [ABSTRACT FROM AUTHOR]

Featured Application: Resource and environmental effects of the Tibetan Plateau. Himalayan orogenesis remains enigmatic in terms of Tibetan Plateau geodynamics originating from the Cenozoic India–Eurasian continental collision. India underthrusts below Tibet to the Yarlung–Tsangpo suture, which has been identified as the northernmost boundary for underplating. However, the way in which the historical evolution of continental subduction induces plateau uplift and the way it controls the variation in uplift between outboard and inboard areas is still unclear. To interpret the evolutionary mechanisms involved in the Himalayan growth history, we constructed different 3-D dynamic models at important stages to address these questions related to the formation of the Himalayas on the basis of paleoenthalpy evidence encoded in fossil leaves from recently documented assemblages in southern Tibet. The results show that (1) the effect of crustal thickening was the predominant factor in the early evolution from the Paleocene to the early Eocene, which resulted in a moderate growth rate. (2) The consecutive slab break-off eastward from the western syntaxis and the associated slab rebound significantly accelerated orogenesis from the late Eocene to the Oligocene. The upwelling asthenospheric flow was a key control of increasing crustal buoyancy, which resulted in the fastest growth of the Himalayas during the early Miocene. (3) Thereafter, the gradually enhanced monsoon and surface erosion during accompanying the increasing mountain height resulted in a slowdown of the orogenic rate, which counterbalanced the buoyant force produced by asthenospheric flow driving continuous Himalayan growth. [ABSTRACT FROM AUTHOR]

Analyzing free-bending pipelines in cluttered 3-D scenarios is a vital and challenging task in industrial manufacture and maintenance. It is beneficial in understanding the structure of pipelines and monitoring pipeline spacing for accurate assembly. Most existing pipeline analysis algorithms focus on regular straight pipelines and only depend on 3-D spatial cues. In this article, we propose a novel pipeline analysis framework based on 4-D spatiotemporal pipeline representation. The framework allows multiple pipeline analysis tasks ranging from detecting free-bending pipelines in point clouds and extracting 3-D skeletons to modeling complete 3-D pipelines. The 4-D pipeline representation formulates a free-bending pipeline as a 3-D cylinder sequence and incorporates 3-D spatial geometrization of each cylinder frame into temporal continuity of the frames. The multitask pipeline analysis starts from a cylinder patch and is performed on sequential pipeline frames using spatiotemporal cues. Finally, surface registration-based optimization refines pipeline skeletons, detected point cloud, and generated complete models simultaneously. The proposed algorithm is verified on real pipeline scenarios. It can deal with challenging free-bending pipeline shapes, clutter, and occlusions. Compared with existing algorithms, our algorithm achieves more comprehensive tasks and higher detection performance. The modeling of complete pipelines reaches an overall accuracy of 0.33 mm. Finally, we present a thorough analysis concerning the applicability of our algorithm from multiple aspects. [ABSTRACT FROM AUTHOR]

The blue carbon ecosystem, including the salt marsh ecosystem, possesses a significant carbon sequestration potential. Therefore, accurately quantifying the carbon storage within such ecosystems is crucial for the adequate accounting of carbon sequestration. The present work chose a Spartina alterniflora ecosystem in the Xiaogan Island (China) as the study area (approximately 11 ha), and employed the Bayesian maximum entropy (BME) approach to assimilate both hard organic carbon (OC) data and soft OC data measured from 2 cm and 10 cm stratified samples. A 3-dimensional model was developed for space-time OC estimation purposes based on the sediment chronology results. The 10-fold BME cross validation results demonstrated a high estimation accuracy, with the R2, RMSE and MAE values equal to 0.8564, 0.1026 % and 0.0748 %, respectively. A noteworthy outcome was the BME-generated carbon storage density maps with 1 m spatial resolution. These maps revealed that the carbon storage density at the top 30 cm sediment depth in the stable zone (with elder stand age of S. alterniflora) was higher than that in the rapid expansion zone, i.e., 71.79 t/ha vs. 69.82 t/ha, respectively. Additionally, the study found that the averaged carbon burial rate and the total carbon storage at the top 30 cm sediment depth across the study area were 266 g C/m2/yr and 781.50 t, respectively. Lastly, the proposed BME-based framework of carbon storage estimation was found to be versatile and applicable to other blue carbon ecosystems. This approach can foster the development of a standardized carbon sink metrological methodology for diverse blue carbon ecosystems. • Carbon storage in salt marsh ecosystem was estimated at a spatial resolution of 1 m. • BME exhibited versatile ability for carbon storage estimation in a space-time domain. • Stand age of Spartina Alterniflora positively related to the carbon storage in sediment. [ABSTRACT FROM AUTHOR]

Abstract Determining the width of an induced hydraulic fracture is the first step for applying wellbore strengthening and hydraulic fracturing techniques. However, current 2-D analytical solutions obtained from the plane strain assumption may have large uncertainties when the fracture height is small. To solve this problem, a 3-D finite element method (FEM) is used to model wellbore strengthening and calculate the fracture width. Comparisons show that the 2-D plane strain solution is the asymptote of the 3-D FEM solution. Therefore, the 2-D solution may overestimate the fracture width. This indicates that the 2-D solution may not be applicable in 3-D conditions. Based on the FEM modeling, a new 3-D semi-analytical solution for determining the fracture width is proposed, which accounts for the effects of 3-D fracture dimensions, stress anisotropy and borehole inclination. Compared to the 2-D solution, this new 3-D semi-analytical solution predicts a smaller fracture width. This implies that the 2-D-based old design for wellbore strengthening may overestimate the fracture width, which can be reduced using the proposed 3-D solution. It also allows an easy way to calculate the fracture width in complex geometrical and geological conditions. This solution has been verified against 3-D finite element calculations for field applications.

Himalayan orogenesis remains enigmatic in terms of Tibetan Plateau geodynamics originating from the Cenozoic India–Eurasian continental collision. India underthrusts below Tibet to the Yarlung–Tsangpo suture, which has been identified as the northernmost boundary for underplating. However, the way in which the historical evolution of continental subduction induces plateau uplift and the way it controls the variation in uplift between outboard and inboard areas is still unclear. To interpret the evolutionary mechanisms involved in the Himalayan growth history, we constructed different 3-D dynamic models at important stages to address these questions related to the formation of the Himalayas on the basis of paleoenthalpy evidence encoded in fossil leaves from recently documented assemblages in southern Tibet. The results show that (1) the effect of crustal thickening was the predominant factor in the early evolution from the Paleocene to the early Eocene, which resulted in a moderate growth rate. (2) The consecutive slab break-off eastward from the western syntaxis and the associated slab rebound significantly accelerated orogenesis from the late Eocene to the Oligocene. The upwelling asthenospheric flow was a key control of increasing crustal buoyancy, which resulted in the fastest growth of the Himalayas during the early Miocene. (3) Thereafter, the gradually enhanced monsoon and surface erosion during accompanying the increasing mountain height resulted in a slowdown of the orogenic rate, which counterbalanced the buoyant force produced by asthenospheric flow driving continuous Himalayan growth.

Delineating the boundary between troposphere and stratosphere in a chemistry transport model requires a state variable for each air mass that maps out the ever shifting, overlapping three-dimensional (3-D) boundary at each time step. Using an artificial tracer, e90, with surface sources and 90 day decay time, the model e90 tropopause matches the 1-D temperature lapse rate definition of the tropopause as well as the seasonal variation of ozone at this boundary. This approach works from equator to pole, over all seasons, unlike methods based on potential vorticity or ozone. By focusing on the time scales that separate stratosphere from troposphere, we examine the cause of ozone seasonality at the midlatitude tropopause, the oldest air in the troposphere (winter descent in the subtropics), and a north-south bias in the age of air of the lowermost stratosphere as evaluated using a northern tracer. The tracer e90 is invaluable in 3-D modeling, readily separating stratosphere from troposphere and a giving quantitative measure of the effective distance from the tropopause.

We show that high‐resolution aeromagnetic surveys, although rarely employed in the research of salt structures, may be an effective and low‐cost tool for mapping diapirism. A multiscale analysis of a high‐resolution magnetic data set at Nordkapp Basin in the Barents Sea, allows a clear reconstruction of the main salt diapirs of the basin using Multiridge and Compact Depth from Extreme Points methods. We provide a 3‐D model of the diapirs extended from 500 to 4,000 m below sea level, characterized by a general low magnetization contrast no larger than −0.08 A/m. The 3‐D model is consistent with the salt top depth estimated by 2‐D seismics, with borehole data and with the 2‐D gravity model of the Uranus diapir. Our imaging shows the capability of the magnetic method that gives new and comprehensive pictures of salt diapirism. Key Points: We interpret the magnetic field of the Nordkapp Basin by a multiscale approachImaging methods applied to magnetic data can well identify the top, bottom, and shape of saline structuresHigh‐resolution aeromagnetic surveys are a valid and low‐cost tool for mapping diapirism where other methods are not entirely effective [ABSTRACT FROM AUTHOR]

Contribution: The NEWTON fabrication laboratory (Fab Lab) Education Initiative assesses the effectiveness of Fab Lab-based learning on K–12 students’ attitude toward learning science, technology, engineering, art, and mathematics (STEAM). It considers two aspects: 1) students’ motivation and affective state and 2) students’ observations and perception of Fab Lab-based learning. Background: Fab Labs are described as small workshops equipped with a set of computer-controlled tools (e.g., 3-D printers) that offer personalized digital fabrication. They have been shown to have a positive impact on learners’ academic and personal growth when used in extracurricular activities, but little research examines whether integrating Fab Labs into school curricula can help raise student interest in STEAM education. Research Question: Can Fab Lab-based learning foster students’ interest in STEM in primary and secondary schools? Would students be keen to use Fab Labs in their science classes? Methodology: Two case studies were carried out in two different schools as part of the European Horizon 2020 NEWTON project. The study had 39 participants; three different surveys were used to assess different constructs. Findings: Results show that after using the Fab Lab-based learning: 1) students felt more interested in science classes as well as more engaged and less bored and 2) while some students struggled at first when manipulating Fab Lab tools, they adapted quickly and reported that they would like to use Fab Labs as part of their science classes. [ABSTRACT FROM AUTHOR]

In this study, thermal performance and flow characteristics of a shell and tube heat exchanger equipped with various baffle angles were studied. The heat exchanger was operated with distilled water, and a hybrid nanofluid at three concentrations of 0.04% and 0.10% of GNP-Ag/water within Reynolds numbers ranged between 10,000 and 20,000. The thermophysical properties of nanofluid varied with temperature and nanoparticles’ concentration. The baffle angles were set at 45°, 90°, 135°, and 180°. Results showed that the calculated Nusselt number (Nu) could be improved by adding nanoparticles to the distilled water or increasing the fluid’s Reynolds number. At a low Re number, the Nu corresponding to baffle angle of 135° was very close to that recorded for the angle of 180°. At Re = 20,000, the Nu number was the highest (by 35% compared to the reference case), belonging to a baffle angle of 135°. Additionally, results related to friction factor and pressure drop showed that more locations with fluid blocking were observed by increasing the baffle angle, resulting in increased pressure drop value and friction. Finally, the temperature streamlines counter showed that the best baffle angle could be 135° in which maximum heat removal and the best thermal performance can be observed.

Wideband electromagnetic induction sensors have been shown to be more effective than traditional metal detectors at identifying metallic targets of interest when buried near abundant metallic clutter. A promising strategy for performing target identification using wideband data relies on characterizing the target response using a magnetic polarizability tensor (MPT) that is a function of frequency. In this paper, a surface integral method is presented for deriving the MPT in singularity expansion form using a modal decomposition. The method is verified by comparing the singularity expansion for a spherical shell to a derived analytical solution. The expansion coefficients for cylindrical tubes, of various aspect ratios, are compared to experimental results, showing good agreement. Finally, expansion coefficients are given for a disk and are compared to other numerical results. [ABSTRACT FROM AUTHOR]

Determining the width of an induced hydraulic fracture is the first step for applying wellbore strengthening and hydraulic fracturing techniques. However, current 2-D analytical solutions obtained from the plane strain assumption may have large uncertainties when the fracture height is small. To solve this problem, a 3-D finite element method (FEM) is used to model wellbore strengthening and calculate the fracture width. Comparisons show that the 2-D plane strain solution is the asymptote of the 3-D FEM solution. Therefore, the 2-D solution may overestimate the fracture width. This indicates that the 2-D solution may not be applicable in 3-D conditions. Based on the FEM modeling, a new 3-D semi-analytical solution for determining the fracture width is proposed, which accounts for the effects of 3-D fracture dimensions, stress anisotropy and borehole inclination. Compared to the 2-D solution, this new 3-D semi-analytical solution predicts a smaller fracture width. This implies that the 2-D-based old design for wellbore strengthening may overestimate the fracture width, which can be reduced using the proposed 3-D solution. It also allows an easy way to calculate the fracture width in complex geometrical and geological conditions. This solution has been verified against 3-D finite element calculations for field applications. [ABSTRACT FROM AUTHOR]

High-strength steel suffers from an increasing susceptibility to solidification cracking in welding due to increasing carbon equivalents. However, the cracking mechanism is not fully clear for a confidently completely crack-free welding process. To present a full, direct knowledge of fracture behavior in high-strength steel welding, a three-dimensional (3-D) modeling method is developed using the extended finite element method (XFEM). The XFEM model and fracture loads are linked with the full model and the output of the thermo-mechanical finite element method (TM-FEM), respectively. Solidification cracks in welds are predicted to initiate at the upper tip at the current cross-section, propagate upward to and then through the upper weld surface, thereby propagating the lower crack tip down to the bottom until the final failure. This behavior indicates that solidification cracking is preferred on the upper weld surface, which has higher weld stress introduced by thermal contraction and solidification shrinkage. The modeling results show good agreement with the solidification crack fractography and in situ observations. Further XFEM results show that the initial defects that exhibit higher susceptibility to solidification cracking are those that are vertical to the weld plate plane, open to the current cross-section and concentratedly distributed compared to tilted, closed and dispersedly distributed ones, respectively.

Surface nuclear magnetic resonance (SNMR) technique has been widely applied to noninvasive groundwater exploration and aquifer quantitative characterization. Furthermore, it has the potential for studying and detecting hydrocarbon contaminants and for water resource management. To increase the tomography resolution of groundwater and expand the application range of SNMR, we first implemented its 3-D forward modeling using a vector finite-element (FE) method based on the total electric field. The key of SNMR forward modeling is the calculation of excitation magnetic field, and the total-field algorithm is an alternative scheme to numerically simulate the electromagnetic field. In this paper, we viewed the circular loop source as the combination of a certain number of horizontal electric dipoles. The unstructured tetrahedral mesh and local refinement technology were combined to precisely delineate the distribution of circular loop source, which effectively reduces the adverse effects of field source singularity. Then, the vector FE solver based on the total electric field was used to calculate the magnetic field distribution. The accuracy of the calculated results was validated by the analytical solutions for a circular loop laid on the surface of a homogeneous half-space. After calculating the excitation field, SNMR responses of three typical synthetic 3-D groundwater models were obtained with the basic signal response formula. Finally, we studied the effects of some important factors which have significant influences on SNMR signal responses and have practical importance in groundwater issues. [ABSTRACT FROM AUTHOR]

In the context of a 10-day summer camp makerspace experience that employed design-based learning (DBL) strategies, the purpose of this descriptive case study was to better understand the ways in which children use visualization skills to negotiate design as they move back and forth between the world of nondigital design techniques (i.e., drawing, 3-D drawing with hot glue, sculpture, discussion, writing) and digital technologies (i.e., 3-D scanning, 3-D modeling, 3-D printing). Participants included 20 children aged 6-12. This research was guided by Vossoughi, Hooper, and Escudé's (2016) call for explicit attention to pedagogical practices during the integration of "making" activities. Content analysis was used to analyze qualitative data, including observation, researcher/facilitator field notes, think aloud protocols, daily reflective exit tickets, and participant artifacts. Findings highlight the ways in which participants negotiated visualization skills through (a) imagining, drawing, and seeing through creating 2-D sketches, (b) reasoning and relating through writing stories, (c) transforming through 3-D extrusion, (d) observing and noticing through 3-D sculpting and 3-D scanning, and (e) manipulating through digital 3-D modeling, mental rotation, and mental transformation. Implications for formal K-12 educational contexts and teacher preparation programs are discussed. [ABSTRACT FROM AUTHOR]

Functionality of an infrastructure is its ability to provide its intended services. Maintaining an acceptable level of infrastructure functionality, particularly for critical infrastructure, following an extreme event is vital for effective community recovery. Estimating functionality depends on proper quantification of losses, which requires accurate assessment of infrastructure damage. The damage is presented in the form of fragility functions that are generally developed using nonlinear finite element analysis. To date, no study has been conducted to assess the effect of modeling approach on seismic fragilities of an infrastructure, the associated losses, and functionality reduction. In addition, existing frameworks for estimating functionality of critical infrastructure, such as a hospital, following an extreme event have not considered the interdependent relationship between a hospital and other lifelines. In this study, a new framework for evaluating immediate functionality of a hospital following an earthquake is presented. The functionality is estimated based on hospital losses that result from its sustained damage as well as damage to other lifelines on which the hospital relies. In addition, the effects of modeling resolution on the calculated fragilities, the estimated direct losses, and the associated functionality are evaluated. The hospital models vary from simplified 2-D with idealized boundary conditions to more comprehensive 3-D models that account for soil-structure interaction. The analysis show that using simplified 2-D models that ignore soil-structure interaction could lead to non-conservative results. On the contrary, using more refined 3-D models could provide accurate estimation of the behavior, and subsequently better assessment of losses and functionality. [ABSTRACT FROM AUTHOR]

X-ray tomography is used to produce three-dimensional images of an aluminium alloy foam with a high porosity ( > 93 % ). These data allow describing the foam structure from which a finite element model is derived to predict the thermal conductivity of the foam. The results are compared with experimental values measured by a new guarded hot plate apparatus adapted for the range of thermal conductivity values of interest. Good agreement is observed which validated the finite element model used to evaluate the thermal properties of any porous metallic foam with stochastic cell size and configuration. Furthermore, the thermal conductivity of the foam has also been predicted using previous analytical models. The differences with previous values show that it is important to account for the real geometry of the foam to get an accurate value of the thermal conductivity. [ABSTRACT FROM AUTHOR]

Numerical finite element analysis is considered a reliable tool for response assessment of structures under extreme loadings. When developing finite element models, various geometrical and behavioral assumptions are typically made to simplify the modeling approach and to save on computational cost. The effect of these assumptions on analysis results, however, could be substantial and might significantly alter the decisions pertaining to design, assessment, or retrofit of the structure considered. The importance of accurate modeling, particularly of critical infrastructures, can be vital for post-disaster recovery management following an extreme event. In this study, the seismic response of a six-story hospital building with buckling-restrained braces, located in Memphis, Tennessee, is evaluated for different modeling resolution levels. Different pushover and non-linear time-history analyses are conducted to understand, compare, and evaluate the seismic performance of the structure using both 2-D and 3-D numerical models with and without soil. Various nonlinear features are considered in the simulations including realistic hysteretic behavior of the connections, buckling-restrained braces, and soil-foundation-structure interaction. The results highlight the importance of including representative member and connection models as well as realistic boundary conditions, while employing 3-D simulations, for accurate predictions of system response. [ABSTRACT FROM AUTHOR]

Rare and precious window elements from the Paleochristian Basilica of Saint Sabina in Rome, made of plaster gypsum with translucent selenite used as glass for light transmission, were discovered by Antonio Muñoz during the restoration of the building at the beginning of the 20th c. Originally standing within the stone window frame, were then mounted on wood planks with screws for holding together the scattered fragments. The surfaces were covered with grime and the selenite elements were blinded by the wooden supports. During the recent conservation treatment at ISCR, traces of Egyptian blue on the internal surfaces were detected. Cleaning with laser allowed their conservation and the removal of gypsum deposits from the fragile selenite. 3-D scanning was performed for milling, out of polystyrene blocks, the counterforms that were needed for turning the artifacts upside down. After cleaning and re-assembling of the fragments, a new 3-D scan was performed to obtain a complete model of the artifacts that was used to define the best orientation of the windows, both for exhibition purposes and for the distribution of the weight-related stresses. Following a project based on 3-D modeling, exhibition stands were produced with a core material milled out of PET foam, reinforced with outer skins made with carbon fiber adhered under vacuum to the core material with epoxy resin. The new exhibition stands, very light and rigid, permit all-round appreciation of the artifacts and allow the light to shine through the selenite elements. [ABSTRACT FROM AUTHOR]

This paper presents performance improvements of a double excitation synchronous motor by using a reluctance network (RN). The distinguishing feature of the double excitation principle is to use permanent magnets with high energy, while air-gap flux is flexibly controlled by field windings. Therefore, the first contribution of this paper focuses on maximizing air-gap flux range control. Second, an approach for torque ripple reduction is proposed by directly modifying air-gap flux according to the instantaneous torque profile. The achieved resultant torque stays almost constant for a case study. The validity of the RN method is examined by comparisons with 3-D finite element and experimental results for several machines. [ABSTRACT FROM AUTHOR]

Along many Mediterranean coasts, the detached seagrass material of Posidonia oceanica creates seagrass berms that control the structure and morphodynamics of sandy beaches. Here, we show how Terrestrial Laser Scanner remote sensing data allows analyzing the 3-D morphologic change of beaches where this characteristic geomorphic structure is present. We propose a methodology for estimating accretion/erosion (almost −200 m3 in our study) by considering the sand dominated and seagrass berms as two independent elements. For this purpose, two different sampling dates (named scenarios A and B, before and after an erosive heavy storms period, respectively) recorded in a microtidal pocket-beach (300 m2) with these characteristic geomorphic structures have been modeled in 3-D. The present approach constitutes a cost-efficient, accurate, and quick tool to survey the sand volume in natural and artificial replenished beaches. The innovative approach, which can be considered as a conceptual and methodological starting point, can be useful to examine long-term and high-precision data sets in future studies of the morphodynamic evolution of these characteristic Mediterranean beaches.

• A 3-D simulation for in-depth analysis of a desiccant-coated heat exchanger. • Mass and energy balances are coupled with species transports and reaction kinetics. • Time-dependent and spatial distributions of reaction, temperature, and water. • Parametric analysis of dehumidification performance in tropical weather conditions. High-performance desiccant-coated heat exchangers (DCHEs) can be employed in air-conditioning systems to improve energy efficiency. While there are significant developments in experimental studies, theoretical approaches for analyzing the DCHE are impeded by the complex and coupled heat and mass transport mechanisms. Therefore, a 3D mathematical model has been developed in this work to study the dehumidification performance of a DCHE. Unlike other works reported in the literature, the developed model is able to simulate the complex coupling between heat and mass transfers in the entire volume of the heat exchanger. The model is calibrated and validated with experimental data, and a maximum discrepancy of ±8 % is recorded. A time-dependent study on the performance of the DCHE is carried out to understand the distribution of temperature, reaction rates, and water uptake in the heat exchanger. Effects of key influencing operational factors are investigated and discussed. It is indicated that the DCHE enters a stable performance state regardless of its initial adsorption state. The regeneration time should be equal to the dehumidification time to optimize the performance. A higher thermal COP is achieved under lower cooling/regeneration temperature, lower air flowrate, and shorter half-cycle time, while higher inlet air humidity ratio. Higher coated desiccant mass also provides a higher thermal COP , but this enhancement levels off once the coating grows. For DCHEs with less coating, reducing cycle time is recommended over increasing the coating amount. [ABSTRACT FROM AUTHOR]

In this work we have investigated 2-D images in order to create 3-D visualization and animation of movement of dog forelimb. The aim of study was to present the possibilities and advantages on softer design for displaying 2-D images in animated 3-D motion picture. For that purpose we have prepared animation with refer to modern 3-D modeling by using high developed software - Avid Softimage XSI. For precise reconstruction of forelimb bones we used 3-D scan witch was performed with color laser for scanning a different objects. Based of data obtained from CT and MR images there are a possibility that computer modeling can be used as a toll for recognition of special anatomical features on images prepared with Computer Tomography (CT) or Magnet Resonance (MR)

An industrial size vertical Direct Chill (DC) caster fitted with a porous filter above the mold is simulated by developing control volume finite difference based computational fluid dynamics code. Specifically, the 3-D laminar/turbulent melt flow in the sump and mushy zone solidification characteristics in the DC caster are modeled for aluminium alloy AA-1050. To account for the turbulence in the sump a popular version of the low Reynolds number κ − ɛ model is employed. A single domain enthalpy-porosity approach is used to account for the solidification heat transfer of the above short solidification range alloy. The melt flows through the stainless steel porous filter placed near the top of the caster is modeled using the Brinkman–Forchheimer extended Darcy equation and by invoking the local thermal equilibrium condition between the melt and the porous structure. The verified code is used to study the effects of casting speed and heat transfer coefficient in the metal-mold contact region on various aspects of this casting problem. Sensitivity analysis is also carried out by varying the latent heat of solidification of the said alloy. The predicted results are presented and discussed for the solid-shell thickness, the sump depth, the mushy layer thickness as well as for the temperature and velocity fields. [ABSTRACT FROM AUTHOR]

Modern satellites tag their images with geolocation information using GPS and star tracking systems. Depending on the quality of the geopositioning equipment, errors may range from a few meters to tens of meters on the ground. At the current state of art, there is no established method to automatically correct these errors limiting the large-scale joint utilization of cross-platform satellite images. In this paper, an automatic geolocation correction framework that corrects images from multiple satellites simultaneously is presented. As a result of the proposed correction process, all the images are effectively registered to the same absolute geodetic coordinate frame. The usability and the quality of the correction framework are demonstrated through a 3-D surface reconstruction application. The 3-D surface models given by original satellite geopositioning metadata, and the corrected metadata, are compared. The quality difference is measured through an entropy-based metric applied to the orthographic height maps given by the 3-D surface models. Measuring the absolute accuracy of the framework is harder due to lack of publicly available high-precision ground surveys. However, the geolocation of images of exemplar satellites from different parts of the globe are corrected, and the road networks given by OpenStreetMap are projected onto the images using original and corrected metadata to demonstrate the improved quality of alignment. [ABSTRACT FROM AUTHOR]

To find the real risk points of internal dielectric charging (IDC), 3-D IDC simulation is performed to a typical dielectric structure considering GEO severe radiation environment (FLUMIC3). Charge transportation simulation is carried out by Geant4 and electric field is numerically computed according to the current conservation law. The aluminum shielding thickness is varied to investigate the shielding dependence. By adjusting the lower energy limit of the incident electron spectrum according to the shielding thickness, a technique is proposed to improve the simulation efficiency. The statistic condition in Geant4 is checked and attention is paid to the influence of mesh on the peak electric field. The simulation data show that the peak electric field occurs on the grounding edge and local mesh refinement on the critical charging point is of significance to make sure the real charging level. Increasing the shielding thickness could mitigate IDC. However, this mitigation effect is weak in the case where radiation-induced conductivity dominates the total conductivity (at low temperature). In this case, even using a 3-mm aluminum shielding, the peak electric field can reach the level of 10^7 V/m. [ABSTRACT FROM AUTHOR]

Three-dimensional synthetic modeling of magnetotelluric sounding data of the Yucatán peninsula suggests that the coast effect on the magnetotelluric measurements carried out over the Chicxulub impact region is negligible. The marine platform surrounding the Yucatán peninsula yields a moderate coast effect in a period range T= 10 to 1000 s, outside of the period range associated wih the conductivity anomaly of the crater (T= 1 to 10 s). These results provide a framework for the interpretation of MT soundings previously obtained in the Chicxulub crater and define other areas for future MT surveys in the Yucatán peninsula.

In recent years, electrical field distribution is the area of major concern in the service life of Polymeric Insulators. Several methodologies are proposed to analyze the electrical field along the insulators both experimentally and numerically of which the former might be very time consuming requiring a number of trial-error tests to determine the optimum dimensions. The advent of super computers makes numerical analyses feasible on any complex geometry modeled in 3-D and the overall optimization techniques to control the electrical field become quite easier. However, the main drawbacks in 3-D analyses are the more computation time and memory, making it desirable to simplify the structure. Hence a methodology based on relationship between electrical field profiles of 2-D (axi-symmetry model of insulator with corona ring) and 3-D model (insulator with corona ring, tower, 3 phase hardware fittings and conductors) for a dimension and location of corona/grading rings is proposed. Based on the relationship, electrical field profiles of 3-D models are predicted for different dimension and location of rings using its equivalent 2-D model electrical field profile. Commercially available 2-D and 3-D finite element based electrostatic field computation program is used. A 220 kV suspension type I string assembly is used for this study. Later, the approach is validated for 132 kV and 400 kV insulators. The type of tower, string configuration is kept constant throughout the analyses. [ABSTRACT FROM AUTHOR]

The field reconstruction method (FRM) is a recent technique for modeling electrical machines. This method offers the same accuracy as the finite element analysis at a lower computational cost by using a few prestored results, which are known as the basis functions. This paper describes an enhanced three-dimensional (3-D) FRM for modeling an axial flux permanent magnet machine. This machine has a special structure, which warrants the use of 3-D modeling for completely describing its behavior. The proposed method can be an efficient solution for the 3-D modeling of electrical machinery, especially from the viewpoint of time-varying and iterative optimization problems. Experimental and simulation results are provided to validate the proposed method's precision. [ABSTRACT FROM AUTHOR]

3-D modeling, object detection, and pose estimation are three of the most challenging tasks in the area of 3-D computer vision. This paper presents a novel algorithm to perform these tasks simultaneously from unordered point-clouds. Given a set of input point-clouds in the presence of clutter and occlusion, an initial model is first constructed by performing pair-wise registration between any two point-clouds. The resulting model is then updated from the remaining point-clouds using a novel model growing technique. Once the final model is reconstructed, the instances of the object are detected and the poses of its instances in the scenes are estimated. This algorithm is automatic, model free, and does not rely on any prior information about the objects in the scene. The algorithm was comprehensively tested on the University of Western Australia data set. Experimental results show that our algorithm achieved accurate modeling, detection, and pose estimation performance. [ABSTRACT FROM PUBLISHER]

3-D object modeling from single images has many applications in computer graphics and multimedia. Most previous 3-D modeling methods which directly recover 3-D geometry from single images require user interactions during the whole modeling process. In this paper, we propose a semi-automatic 3-D modeling approach to recover accurate 3-D geometry from a single image of a piecewise planar object with less user interaction. Our approach concentrates on these three aspects: (1) requiring rough sketch input only, (2) accurate modeling for a large class of objects, and (3) automatically recovering the invisible part of an object and providing a complete 3-D model. Experimental results on various objects show that the proposed approach provides a good solution to these three problems. [ABSTRACT FROM AUTHOR]

What began as a life partnership has evolved into an early learning STEAM team. Artist, David Thompson, uses science, technology, engineering and math, on a daily basis, to create robots and much more. Teresa Day Walker is an assistant professor of early childhood education. Through necessity they discovered their combined talents could be used to promote STEAM in early childhood. David and Teri teamed up to provide a nearly impromptu robot making demonstration for 100 kindergarten students. After reading their coauthored book, Robot Hide and Seek, both, clay based and 3-D modeled images were used to generate interest and discussion. Ultimately, Boom, a resin robot, took center stage during the engaging hands-on casting demonstration as he evolved from two separate chemicals, into his combined liquid state, and finally his solid self. [ABSTRACT FROM AUTHOR]

The problem of desiccation cracks in soils has received increasing attention in the last few years, in both experimental investigations and modeling. Experimental research has been mainly focused on the behavior of slurries subjected to drying in plates of different shapes, sizes and thickness. The main objectives of these studies were to learn about the process of crack formation under controlled environmental conditions, and also to understand better the impact of different factors (e.g. soil type, boundary conditions, soil thickness) on the morphology of the crack network. As for the numerical modeling, different approaches have been proposed to describe the behavior of drying cracks in soils. One aspect that it is still difficult to simulate properly is the 3-D crack pattern typically observed in desiccated soils. In this work we present a numerical technique to model the behavior of drying soils. The proposed approach inserts high aspect ratio elements in-between standard elements of a finite element mesh. This mesh fragmentation technique can be easily adapted to standard finite element programs. We used this technique to analyze multiple case studies related to soil desiccation cracks developed under laboratory and field conditions. We focused our attention in some key factors that control the 3-D morphology of the drying cracks network in soils. We show that the proposed technique is able to simulate very satisfactorily the main patterns typically observed in cracked soils. [ABSTRACT FROM AUTHOR]

Abstract: A 3-D CFD model coupled with turbulent melt flow and heat transfer with solidification is developed to simulate an industrial-sized vertical direct chill (DC) slab caster for aluminum AA-1050 alloy. In a DC casting process, a melt distributor is used to feed melt to the mold to minimize the temperature gradient between the hottest and coldest areas. This study considered a new melt distributor which consisted of a submerged nozzle underneath of which there was a porous filter occupying the entire transverse cross-section of the caster. The whole assembly was placed inside the hot-top above the mold. Simulations were carried out by varying three different important parameters of the problem, namely, the casting speed from 40 to 100mm/min, the effective heat transfer coefficient at the mold-metal contact region from 0.75 to 3.0kW/(m2 K), and the Darcy number of the porous filter from 10−6 to 10−3. For all parametric cases, the inlet melt superheat was 32°C and the porosity of the filter was taken as 0.4. Detail results in the form of velocity and temperature profiles, solid shell thickness, sump depth and local surface heat flux are predicted and compared. [Copyright &y& Elsevier]

The use of three-dimensional computer models in archaeological projects is a relatively new but rapidly growing area, both as a means of presenting research to the public and also as an aid to interpretation. This work uses the House of the Surgeon in Pompeii as a case study and seeks to illustrate the most effective ways to display information to a range of audiences. In using the flexibility of computer modelling techniques it seeks to show that the levels of detail in a 3-D computer model can be tailored to individual circumstances to produce the most effective result.

This paper describes a printed circuit board (PCB) design course based on electromechanical workflow. The course relies on the premise that a PCB is an integral component of any electronic apparatus, along with its other electromechanical and mechanical components. To emphasize this to students, electrical and mechanical computer-aided design tools are used in synergy. The course content is described in detail, and the design workflow is illustrated, using a project to design a data acquisition instrument as an example. [ABSTRACT FROM AUTHOR]

Total ankle replacement (TAR) is a relatively new concept and is becoming more popular for treatment of ankle arthritis and fractures. Because of the high costs and difficulties of experimental studies, the developments of TAR prostheses are progressing very slowly. For this reason, the medical imaging techniques such as CT, and MR have become more and more useful. The finite element method (FEM) is a widely used technique to estimate the mechanical behaviors of materials and structures in engineering applications. FEM has also been increasingly applied to biomechanical analyses of human bones, tissues and organs, thanks to the development of both the computing capabilities and the medical imaging techniques. 3-D finite element models of the human foot and ankle from reconstruction of MR and CT images have been investigated by some authors. In this study, data of geometries (used in modeling) of a normal and a prosthetic foot and ankle were obtained from a 3D reconstruction of CT images. The segmentation software, MIMICS was used to generate the 3D images of the bony structures, soft tissues and components of prosthesis of normal and prosthetic ankle-foot complex. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and calcaneus bones, soft tissues and components of prosthesis were independently developed to form foot and ankle complex. SOLIDWORKS program was used to form the boundary surfaces of all model components and then the solid models were obtained from these boundary surfaces. Finite element analyses software, ABAQUS was used to perform the numerical stress analyses of these models for balanced standing position. Plantar pressure and von Mises stress distributions of the normal and prosthetic ankles were compared with each other. There was a peak pressure increase at the 4th metatarsal, first metatarsal and talus bones and a decrease at the intermediate cuneiform and calcaneus bones, in prosthetic ankle-foot complex compared to normal one. The predicted plantar pressures and von Misses stress distributions for a normal foot were consistent with other FE models given in the literature. The present study is aimed to open new approaches for the development of ankle prosthesis. [ABSTRACT FROM AUTHOR]

Multitemporal hyperspectral images are gaining an ever-increasing importance revealed by the ambition of the remote sensing community to develop new generation of sensors. Therefore, multitemporal images classification and change detection issues are greatly relevant in several research topics. In this paper, we propose a novel approach for modeling the temporal variation of the reflectance response as a function of time period and wavelength; summarizing the spectral signature of hyperspectral pixels as a 3-D mesh. This approach is adopted for hyperspectral time series analysis leading to the main following contribution: an advanced form of the temporal spectral signature defining the reflectance at each pixel as a congregation of the spatial/spectral/temporal dimensions. Afterward, by formulating the temporal data set in an adequate multidimensional feature space of contextual data, an innovative processing scheme exploiting the theoretical backgrounds of 3-D surface reconstruction and matching is adopted for data interpretation. Finally, an improved method for multitemporal endmember extraction and spectral unmixing based on multilinear algebra methods is introduced. A case study, in a region located in southern Tunisia, is conducted on a multitemporal subset of Hyperion images. Up to 89.86% of sampling sites have been correctly predicted by the proposed approach, outperforming conventional classifiers. The good performances obtained, on simulated multitemporal images and over various real experimental scenarios, illustrate the effectiveness and the generalization capacities of the proposed approach. [ABSTRACT FROM AUTHOR]

Most of the simulation models about arc plasma are based on the hypothesis of local thermal equilibrium (LTE). The nonequilibrium model is very complicated due to the calculation of electron temperature. In this paper, an improved LTE model is developed and applied to the 3-D simulation of the flow patterns inside a nontransferred dc arc plasma torch. Numerical calculations on the distributions of gas temperature and velocity in the plasma torch were carried out using argon as the plasma gas. The electric current density and potential are also discussed. The results indicate that the temperature and velocity distributions of the arc are almost axisymmetrical. The results of voltage drop agree well with the experimental observations. It seems that anode erosion is located on the internal surface of the anode, where the largest number of electrons is injected. [ABSTRACT FROM AUTHOR]

This paper considers analytical and numerical techniques to model the magnetic field distribution in a tubular actuator with skewed permanent magnets (PMs). A fast 3-D analytical model based on Fourier analysis is developed for calculation of the various field components resulting from the skewed PMs for various skewing topologies. This techniques provides means for validating the assumptions of 2.5-D multilayer methods. Furthermore, a 2.5-D analytical multilayer model is derived for calculation of the cogging force due to the slot openings including skewed PMs. The analytical methods are validated by means of 3-D finite element analysis. [ABSTRACT FROM PUBLISHER]

Abstract: In this work, a series of numerical simulations has been devised to study the performance of granular superhydrophobic surfaces under elevated hydrostatic pressures. Using balance of forces, an analytical expression has also been developed to predict the critical pressure at which a submersed idealized granular superhydrophobic surface comprised of spherical particles, orderly packed next to one another, departs from the Cassie state. Predictions of our analytical expression have been compared with those of a series of 3-D full-morphology numerical simulations, and reasonable agreement has been observed between the two methods. Full-morphology simulations were then used, for the first time, to compute the critical pressure of superhydrophobic surfaces comprised of randomly distributed spherical particles (e.g., superhydrophobic coatings developed by depositing of hydrophobic aerogel particles), where no analytical method is applicable due to the complexity of the coatings’ morphology. Results of our numerical simulations indicate that for coatings made up of mono-disperse hydrophobic particles, critical pressure increases with increasing the solid volume fraction. However, increasing particle diameter results in lower critical pressures when the coating''s solid volume fraction is held constant. [Copyright &y& Elsevier]

In this paper, a 3-D model based on the Green's function for analyzing wave propagation in 2-D guided-wave photonic crystals (PhCs) is proposed. The model allows analysis all the physical effects occurring when a source field propagates in a multilayered structure with a periodic arrangement of scatterers, by taking into account both physical and geometrical parameters. Numerical results for PhC waveguides are compared with those obtained using the well-known finite-difference time-domain algorithm and the 3-D multiple-scattering technique already proposed in the literature, showing a very good agreement and some remarkable advantages, in terms of faster determination of electromagnetic field distributions and band diagrams and capability to analyze both in-plane and out-of-plane scattering losses. [ABSTRACT FROM PUBLISHER]

Abstract: This work is conducted to better our understanding of the influence of fibers’ in-plane and through-plane orientations on pressure drop and collection efficiency of fibrous media. The Stokes flow equations are numerically solved in virtual, 3-D, fibrous geometries with varying in-plane and/or through-plane orientations. Pressure drop and aerosol collection efficiency characteristics of such media are calculated and compared with available studies from the literature. Our results indicate that pressure drop and submicron particle capture efficiency of common fibrous filters with a fiber diameter of about 10μm are independent of the in-plane orientation of the fibers, but decrease with increasing the fibers’ through-plane orientation. More interestingly, it was found that filters with higher through-plane fiber orientations have a higher figure of merit if challenged with nanoparticles. The figure of merit of these media, however, decreases as the particle size increases, reversing the effect of fibers’ through-plane orientation. It was also shown that when the diameter of the particles is comparable to that of the fibers, collection efficiency increases with decreasing the fibers’ in-plane orientation, while the pressure drop remains almost unchanged. This indicates that decreasing the fibers’ in-plane orientation increased the figure of merit of media made of nanofibers. [ABSTRACT FROM AUTHOR]

Bite force is a measure of whole-organism performance that is often used to investigate the relationships between performance, morphology and fitness. When in vivo measurements of bite force are unavailable, researchers often turn to lever models to predict bite forces. This study demonstrates that bite force predictions based on two-dimensional (2-D) lever models can be improved by including three-dimensional (3-D) geometry and realistic physiological cross-sectional areas derived from dissections. Widely used, the 2-D method does a reasonable job of predicting bite force. However, it does so by over predicting physiological cross-sectional areas for the masseter and pterygoid muscles and under predicting physiological cross-sectional areas for the temporalis muscle. We found that lever models that include the three dimensional structure of the skull and mandible and physiological cross-sectional areas calculated from dissected muscles provide the best predictions of bite force. Models that accurately represent the biting mechanics strengthen our understanding of which variables are functionally relevant and how they are relevant to feeding performance. [ABSTRACT FROM AUTHOR]

Abstract: Very-Long-Chain Acyl-CoA Dehydrogenase deficiency (VLCADD) is an autosomal recessive disorder considered as one of the more common ß-oxidation defects, possibly associated with neonatal cardiomyopathy, infantile hepatic coma, or adult-onset myopathy. Numerous gene missense mutations have been described in these VLCADD phenotypes, but only few of them have been structurally and functionally analyzed, and the molecular basis of disease variability is still poorly understood. To address this question, we first analyzed fourteen disease-causing amino acid changes using the recently described crystal structure of VLCAD. The predicted effects varied from the replacement of amino acid residues lining the substrate binding cavity, involved in holoenzyme–FAD interactions or in enzyme dimerisation, predicted to have severe functional consequences, up to amino acid substitutions outside key enzyme domains or lying on near enzyme surface, with predicted milder consequences. These data were combined with functional analysis of residual fatty acid oxidation (FAO) and VLCAD protein levels in patient cells harboring these mutations, before and after pharmacological stimulation by bezafibrate. Mutations identified as detrimental to the protein structure in the 3-D model were generally associated to profound FAO and VLCAD protein deficiencies in the patient cells, however, some mutations affecting FAD binding or monomer–monomer interactions allowed a partial response to bezafibrate. On the other hand, bezafibrate restored near-normal FAO rates in some mutations predicted to have milder consequences on enzyme structure. Overall, combination of structural, biochemical, and pharmacological analysis allowed assessment of the relative severity of individual mutations, with possible applications for disease management and therapeutic approach. [Copyright &y& Elsevier]