3D Physical Model Research Articles

3D Geophysical Post-Inversion Feature Extraction for Mineral Exploration through Fast-ICA

A major problem in the post-inversion geophysical interpretation is the extraction of geological information from inverted physical property models, which do not necessarily represent all underlying geological features. No matter how accurate the inversions are, each inverted physical property model is sensitive to limited aspects of subsurface geology and is insensitive to other geological features that are otherwise detectable with complementary physical property models. Therefore, specific parts of the geological model can be reconstructed from different physical property models. To show how this reconstruction works, we simulated a complex geological system that comprised an original layered Earth model that has passed several geological deformations and alteration overprints. Linear combination of complex geological features comprised three physical property distributions: electrical resistivity, induced polarization chargeability, and magnetic susceptibility models. This study proposes a multivariate feature extraction approach to extract information about the underlying geological features comprising the bulk physical properties. We evaluated our method in numerical simulations and compared three feature extraction algorithms to see the tolerance of each method to the geological artifacts and noises. We show that the fast-independent component analysis (Fast-ICA) algorithm by negentropy maximization is a robust method in the geological feature extraction that can handle the added unknown geological noises. The post-inversion physical properties were also used to reconstruct the underlying geological sources. We show that the sharpness of the inverted images is an important constraint on the feature extraction process. Our method successfully separates geological features in multiple 3D physical property models. This methodology is reproducible for any number of lithologies and physical property combinations and can recover the latent geological features, including the background geological patterns from overprints of chemical alteration.

Aiming for the Bullseye: Targeted activities decrease misconceptions related to enzyme function for undergraduate biochemistry students.

Biochemistry curricula present a particular challenge to undergraduate students with abstract concepts which can lead to misconceptions that impede learning. In particular, these students have difficulty understanding enzyme structure and function concepts. Targeted learning activities and three-dimensional (3D) physical models are proposed to help students challenge these misconceptions and increase conceptual understanding. Here we assessed such pedagogical tools using the Enzyme-Substrate Interactions Concept Inventory (ESICI) to measure (mis)conceptual changes from Pre- to Post- time points in a single semester undergraduate biochemistry course. A Control group of students engaged with the active learning activities without the 3D physical models and students in the Intervention group utilized these activities with the 3D physical models. At the Post- time point both groups had higher, yet similar ESICI scores of the same magnitude as the highest scoring group from the national sample. Concomitantly, many misconception markers decreased compared to the national sample, although some of these differed between the Control and Intervention groups. Based on this assessment, both pedagogical approaches successfully increased conceptual understanding and targeted many of the misconceptions measured by the ESICI, however, several misconceptions persisted. Surprisingly, the students who used the 3D physical models did not demonstrate a further decrease in the misconception markers. Additionally, psychometric evaluation of the ESICI with our sample recommends the revision of several questions to improve the validity of this assessment. We also offer suggestions to improve instruction and pedagogical tools with further avenues for research on learning.

ARPEC: A novel staggered perforated permeable caisson breakwater for wave absorption and harbour flushing

Perforated multichamber caisson breakwaters are widely used for deep water harbour protection from waves, causing a partial dissipation of wave energy, hence reducing wave reflection. The innovative patented geometry presented in this paper, the ARPEC, is an Anti Reflection PErmeable Caisson breakwater that allows a significant wave energy dissipation and a hydraulic connection between the sea side and the port side by means of a labyrinthine pattern of offset openings in all external and internal walls. The hydraulic response of this innovative structure is evaluated by means of both 2D physical and numerical models. It is shown that, when compared with traditional impermeable perforated caissons, the marginal increase of wave transmission (CT=HT/HI in the approximate range of 0.1–0.2, varying with wave period) is compensated by a slight reduction of wave reflection (CR=HR/HI in the approximate range of 0.3–0.6, varying with wave period) and by an enhanced water circulation in the sheltered basin, which is beneficial for flushing of microtidal harbours.

Numerical and Physical Modelling of Wave Overtopping on a Smooth Impermeable Dike with Promenade under Strong Incident Waves

This paper presents a study of run-up/overtopping over a smooth impermeable dike with promenade using 2D and 3D mesh-based and mesh-free numerical models and results from 2D physical modelling for strong energetic incident waves. These waves induce plunging wave breaking and a complex water/air mixture turbulent flow before overtopped the dike, a challenging configuration for numerical models. The analysis is structured in two phases: (i) evaluates the results of 2D numerical and physical models for run-up and overtopping; (ii) compares qualitatively the results of 3D numerical models for overtopping over a dike with promenade between groins located in front of a slope beach. The results indicate that the main differences obtained in run-up and overtopping are due to differences in wave generation and active absorption systems used in physical and numerical models and in turbulent models used by the numerical models. These differences lead to changes on incident wave height and on wave breaking and, consequently, on reflection, run-up and overtopping over the structure. For 3D simulation, even if larger discrepancies were found on overtopping along the dike, mean wave overtopping discharge and water flow height at the crest of the groin head show a similar order of magnitude.

Delta.AR: An augmented reality-based visualization platform for 3D genome

Delta.AR: An augmented reality-based visualization platform for 3D genome

Three-dimensional Simulation of Forced Convective Flow and Heat Transfer in Air-Cooled Motor Stator

The reliable prediction of cooling medium velocity and stator temperature distribution is very important for a running motor to ensure the temperature rise of stator below the limit. In this paper, taking the stator ventilation duct of an air-cooled motor as the research object, a 3D physical model including the iron core, the windings, the stator ventilation duct and the main insulation was established. In order to fully reveal the characteristics of forced convective flow and heat transfer in air-cooled motor stator, the fluid field and temperature field were calculated by using finite volume method. The radial and axial distribution characteristics of the fluid field were analyzed deeply. It’s shown that the velocity decreases in the axial direction on the half of the axial plane and varies greatly in the radial direction. The temperature distribution in the main insulation layer of the stator was elaborated emphatically. The temperature of the insulation material along the length of the slot and the temperature difference between inner and outer insulation were discussed in detail. Based on the experimental results, the reliability of the calculation method was evaluated and the relative error is within 15%.

Digital Form Finding Using Voronoi Pattern

Starting from funicular models, chain models and hanging membranes, the role of 3D physical models in optimized shape research is the basis of form-finding strategies. Advances in structural optimized shape design derive from the wide spread of special digital form-finding tools. The goal of this paper is to test and evaluate interdisciplinary approaches based on computational tools useful in the form finding of efficient structural systems. This work is aimed at designing an inverse hanging shape subdivided into polygonal voussoirs (Voronoi patterns) by relaxing a planar discrete and elastic system, loaded at each point and anchored along its boundary. The workflow involves shaping, discretization (from pre-shaped paneling to digital stereotomy) and structural analysis carried out using two modeling approaches, finite element and rigid block modeling, using an in-house software tool, LiABlock_3D (MATLAB®), to check the stress state and to evaluate the equilibrium stability of the final shell.

Laboratory Physical Modeling of Rakuna IV Armor Block Stability and Overtopping Discharge of Patimban Port’s Rubble Mound Breakwater

A series of 2D physical model experiment was carried out to examine the potential advantage of Rakuna IV armor block over Tetrapod blocks in term of stability, number of blocks for the same cross-section and overtopping discharge under predetermined experiment conditions. For the sea side slope armor, Rakuna IV – 2ton armor blocks perform advantageous stability in comparison to Tetrapod-2ton blocks for the case of Hmo= 1.2×Hs. For the harbor side slope armor and toe armor, rocks of 300-1000kg/pc performs high stability with very less damage, with S << 2 and S=0.11 respectively (S=2 is initial damage condition). For the crest elevation +2.5mCD, overtopping discharge over either Rakuna IV or Tetrapod armored slopes are more or less at the same amount and both are still within allowed criteria limit. For the crest elevation +2.1mCD, overtopping discharge over Rakuna IV is still within allowed criteria limit. Reduction of breakwater crest from +2.5mCD to +2.1mCD (Rakuna IV) has relatively increased overtopping discharge four times higher, but it is still within allowed criteria limit. For the present experimental design, Rakuna IV armor layer is requiring less number of fabricated blocks for the same cross-section compared to Tetrapod block.

Study on Start-Up Process of SAGD by Solvent: Experiment Research and Process Design

Steam-assisted gravity drainage (SAGD) has been used to develop the “super heavy” oil reservoirs in Canada. The viscosity can reach more than 30,000 cp at 50°C. Moreover, owing to their continental deposit origin, the reservoirs have a low porosity and permeability. Because of these challenges, the conventional steam circulation start-up process takes 6 to 12 months before the well pair can be switched to production. Solvent has been used to start-up SAGD with success. But now, low price of oil and high cost of solvent make solvent-assisted start-up process limited. This paper applies experimental schemes, such as viscosity reduction rate evaluation, core flooding, and 3D physical simulation, tests solvent performance, optimizes process parameters, and designs process solutions. Apply numerical simulation to test solvent-assisted SAGD start-up effect and calculate the cost. This paper researches a unique low-cost solvent compare with xylene. The basic properties and core flood experiment show that the two solvents are similar with viscosity reduction rate, asphalt dissolution rate, and injection pressure, and the price of solvent is 18% lower. The 3D model experiment shows that the average start-up time is reduced by 15%, and steam injection volume is reduced by 21.4%. The numerical simulation results show that without solvent, it will take 180 d for start-up process, and with solvent, the time has reduced by 50% and takes 90 days. Cost calculation results show that the cost will reduce 18% by solvent compared to xylene. Moreover, the production rate has been improved in production stage. This paper applies a 3D physical model to simulate the solvent-assisted SAGD start-up process. Research conclusions show the start-up mechanism of solvent and the process of temperature change of steam chamber.

3D Physical Modeling of an Artificial Beach Nourishment: Laboratory Procedures and Nourishment Performance

Beach nourishment represents a type of coastal defense intervention, keeping the beach as a natural coastal defense system. Altering the cross-shore profile geometry, due to the introduction of new sediments, induces a non-equilibrium situation regarding the local wave dynamics. This work aims to increase our knowledge concerning 3D movable bed physical modeling and beach nourishment impacts on the hydrodynamics, sediment transport, and morphodynamics. A set of experiments with an artificial beach nourishment movable bed model was prepared. Hydrodynamic, sediment transport, and morphological variations and impacts due to the presence of the nourishment were monitored with specific equipment. Special attention was given to the number and positioning of the monitoring equipment and the inherent constraints of 3D movable beds laboratory tests. The nourishment induced changes in the beach dynamics, leading to an increase in the flow velocities range and suspended sediment concentration, and effectively increasing the emerged beach width. Predicting and anticipating the morphological evolution of the modeled beach has a major impact on data accuracy, since it might influence the monitoring equipment’s correct position. Laboratory results and constraints were characterized to help better define future laboratory procedures and strategies for increasing movable bed models’ accuracy and performance.

Experimental and numerical investigation on extra-heavy oil recovery by steam injection using vertical injector -horizontal producer

Steam injection is the most popular used method in recovering heavy oil reservoirs. Many researchers were engaged in enhancing oil recovery (EOR) methods by using various well configurations. Laboratory experiments and field applications have verified the feasibility of extra-heavy oil recovery by steam injection using vertical injector -horizontal producer. It was also referred to as a steam assisted gravity drainage (SAGD) process. However, the characteristic of steam chamber growth and production performance during the vertical injector-horizontal producer steam injection process have not been fully understood. In this study, a 3D physical model was constructed to investigate the mechanisms of the steam injection process using vertical injector-horizonal producer. Numerical simulations were also conducted to verify the laboratory experiment and field application. In the aspect of steam chamber growth, the results revealed that three stages were included during the steam injection process. In the aspect of developing mechanisms, it can be divided into steam flooding and gravity drainage stages. Moreover, the results show that about 43.9% of original oil in place (OOIP) was produced in the gravity drainage stage. In addition, subcool showed significant difference in steam flooding and gravity drainage stages. The temperature distribution mode of the horizontal producer was analyzed and proved to be a significant factor that influences the production performance. Sensitivity analysis by using numerical simulation demonstrated that oil viscosity is the dominant factor that impact the production performance. The results guided the development of pilot test area in Xinjiang Oilfield, China. The study can provide a clearer understanding of the vertical injector-horizontal producer steam injection process in recovering heavy oil reservoirs.

855 Patient Specific Digital Modelling And 3D Printing of Abdominal Anatomy- The Next Frontier in Surgical Simulation?

Abstract Introduction Innovations in digital technologies afford new opportunities in surgical education. We describe a novel method of combining medical imaging data with virtual 3D modelling and printing techniques that could facilitate patient specific pre-operative planning and rehearsal. Method A series of silicone castings was produced to simulate upper abdominal viscera using a novel polyvinyl alcohol (PVA) injection moulding method. Digital models were generated by segmenting CT dual phase imaging in ITK-SNAP. A 3D polygon mesh was exported and optimised in the computer graphics software: Blender. Two 3D printers were used to manufacture a dissolvable mould of the digital models. Moulds were injected with coloured silicones and dissolved in water to reveal the multicolour/multi-material models. Results The silicone models retained the anatomical detail of the digitally segmented CT data sets. The multi-colour models were achieved with a single print and at very low cost (approx. £248/ model) and possessed varying shore hardness between viscera recreating lifelike fidelity. Conclusions The hybrid 3D printing/injection moulding method offers an avenue to realistic surgical and anatomical simulation. A combination of both virtual models and 3D physical models may provide an enhanced surgical experience for preoperative and intraoperative planning allowing patient specific rehearsal.

Virtual Anatomist: A Deep Learning‐based Smartphone Application to Identify Complex Anatomical Features in Augmented Reality

This study pertains to the development of a smartphone mixed-reality (MR) educational app intended to improve the experience of using physical 3D models in classrooms by identifying and labeling various anatomical features on models, built on a deep-learning based computer vision framework. Research at the intersection of MR applications and anatomy education has routinely demonstrated a role for new MR-based modalities in improving anatomy education, but most MR apps rely on custom illustrated projections of 3D-models into user and screen space. These virtual assets are subject to device-intrinsic or developer-based differences in display fidelity and specimen art quality. An intrinsic barrier is present in the development of digital 3D models, which are not trivial to create. Existing evidence also suggests that virtual models may produce inferior results for learning in some use-cases compared to existing physical models. Such evidence forms a case to instead place emphasis on improving the experience of using existing physical models. The described application is hence intended to improve the experience of using real models by labeling anatomical features of interest for the user. The current implementation of the application is trained solely on skull-base anatomy (with class labels including selected bones of the calvarium, paranasal sinuses, and skull processes), but may be extended to other anatomical areas of interest. This labeling is made possible by a hybrid depth-estimation and semantic segmentation-focused machine learning (ML) architecture, which is deployed on consumer-grade smartphones to promote student uptake. When creating ML-based tools, the primary barrier is often the generation of quality ground truth data. Image collections of anatomical specimens must ideally be taken under different conditions, with different augmentations applied to images to improve the ability of the application to robustly recognize and label different parts of a specimen. Manual collection and annotation of the hundreds or thousands of such images required for training is infeasible. However, using procedurally generated images from a 3D-modelled skull (here, in the open-source computer graphics software Blender), developers can produce arbitrarily large, photorealistic ground-truth training datasets with pixel-perfect semantic segmentation of anatomical features. The generalizability of the ML classifier to different models was improved through augmentation of individual renders in Blender by randomizing the model textures; lighting; background environments; skull topology via displacement mapping; the use of “distractor” objects in renders; and camera angles. This work demonstrates the feasibility of developing an anatomical landmark classifier from RGB-image data, trained on fully synthetic data. Future steps include optimization of data augmentations to emphasize shape recognition over texture recognition, formal characterization of segmentation accuracy on cadaveric specimens, and to train alternative models to incorporate depth data, to leverage depth-sensing capabilities that are available on select higher-end mobile devices.

Thermally-induced changes in tropical soils properties and potential implications to sequential nature-based solutions

Some remediation techniques, such as thermal remediation, can significantly change the soil properties. These changes can be beneficial or detrimental to the sequential application of Nature-based Solutions. This work evaluated the effects of thermal remediation on the properties of two tropical soils (Technosol and Oxisol), and discuss how these changes might impact both biotic and abiotic degradation processes. Bench tests using disturbed samples were performed under oxic and anoxic conditions, whereas 3D physical models were used to simulate the heat distribution along undisturbed samples. The changes in soils texture, density, hydraulic conductivity, iron concentration, mineralogy and microbiota were evaluated. The properties of Oxisol were more affected than those of Technosol due to the higher levels in Fe(III), organic carbon and finer texture. When heated in the range of 120 to 300 °C under oxic and anoxic conditions, the Fe(II) content and the magnetism intensity increased in Oxisol, probably due to the formation of magnetite. Under oxic conditions, the burning of Oxisol organic matter promoted an anoxic atmosphere, favoring the formation of Fe(II). However, the continuous increase of the temperature (>300 °C) lead to the decrease of Fe(II) due to the transformation of magnetite to maghemite, and then to hematite. The heating process also promoted some minerals decomposition and cementation of the clay fraction, increasing the soil texture. Bacterial populations were impacted, but showed ability to recover at 60 °C. However, above 100 °C no culturable cells were recovered and at temperatures above 270 °C soil sterilization occurred. The changes observed, especially in Oxisol samples, indicated that mild heating (between 120 and 240 °C), in turn, can increase the potential for abiotic degradation of some contaminants, such as chlorinated solvents. Therefore, heating conditions up to 240 °C during thermal remediation can be defined as to promote beneficial changes in soil properties, increasing its potential for natural attenuation by abiotic processes even when the microbiota is affected, and improving its sustainability.

Improving displacement efficiency by optimizing pad fluid injection sequence during primary cementing of eccentric annulus in shale gas horizontal wells

Displacement efficiency of horizontal wells is mainly affected by casing eccentricity and slurry column structure in the wellbore, and it is an essential precondition for ensuring primary cementing quality. Most current studies use annulus two-phase flow to study the effect of eccentricity on displacement efficiency. In actual cementing conditions, there is multi-phase fluid displacement in the wellbore, including mud, spacer, flusher, and cement. In this study, the computational fluid dynamics (CFD) method is used to analyze three-phase displacement in different eccentric annuli of horizontal wells. An annulus with an eccentricity of 0.4 was selected to simulate different pad fluid injection sequences in the displacement process. The results show that the eccentricity of horizontal wells results in uneven flow velocity on the wide and narrow sides, and higher casing eccentricity results correspondingly in more mud retention volume. While the coupling effect of eccentricity and buoyancy reaches the critical equilibrium state, the displacement interface tends to be short and stable. With an eccentricity of 0.4, the efficiency of three-phase displacement is 85.88%, while the efficiency of four-phase displacement (mud-spacer-flusher-cement) reaches 89.67%. After increasing the volume of cement usage to one and a half annular volumes, the displacement efficiency increases to 95.16%. The results of this study allow better understanding of the casing eccentricity effect, the complex flow physics involved in the combination of spacer and flusher displacement, and optimization of the pad fluid injection sequence to obtain maximum cement displacement efficiency during primary cementing in horizontal wells. • A 3D physical model of the eccentric annulus of horizontal wells is developed. • The displacement process for three-phase fluid in the different eccentric annuli is analyzed. • Different pad fluid injection sequences in the four-phase fluid displacement process are studied. • Displacement efficiency reaches over 95% after pumping one and a half annular volumes of cement.

Multidirectional eigenvalue-based coherence attribute for discontinuity detection

The conventional coherence attribute is typically applied to migrated full-stack seismic data volumes to detect geologic discontinuities. Recently, multispectral, multiazimuth, and multioffset coherence attributes have been proposed and implemented with different seismic data volumes of specific frequencies, azimuths, and offsets to enhance discontinuities. Generally, geologic anomalies, such as faults and channels, will be better illuminated by a perpendicular rather than a parallel direction for computation. Therefore, we have developed a multidirectional eigenvalue-based coherence attribute by establishing multiple covariance matrices along certain different directions on a single poststack volume. We adopt two methods to compute a multidirectional coherence attribute. One is to compute multiple coherence volumes in different directions and to define the minimum as the final multidirectional coherence. This method is time-consuming, but it could provide partial and overall discontinuity simultaneously. The other method obtains one coherence volume by summing covariance matrices in different directions, which is computationally efficient, but only provides overall discontinuity. The performance of our 3D physical model and field data volumes demonstrates that multidirectional coherence can highlight subtle geologic structures with a higher resolution than conventional coherence. This suggests that a multidirectional coherence attribute may serve as an effective tool for detecting the distribution of geologic discontinuities in seismic interpretation.

3D Physical Modelling Study of Shield-Strata Interaction under Roof Dynamic Loading Condition

The dynamic hazards in the open face area caused by the impact load of the massive strong roof become increasingly severe with the increase in the cutting height of the longwall face and its depth of cover. Understanding the strata-shield interaction under the dynamic impact loading condition may relieve the dynamic hazards. In this paper, a 3D physical modelling platform is developed to study the interaction between the roof strata and the longwall shield under the dynamic impact load conditions. A steel plate is dropped to the coal face wall at a certain height above the immediate roof to simulate the free fall of the main roof and the dynamic impact loading environment. The occurrence of major roof falls is modelled at different height above the model and at different positions relative to the longwall faceline. The large-cutting-height and top-coal-caving mining methods are modelled in the study to include the nature of the immediate roof. The results show that the level of face and roof failures depends on the magnitude of the dynamic impact load. The position and height of the roof fall have an important influence to the stability of the roof and face. The pressures on the shield and the solid coal face are relieved for the top-coal-caving face as compared to the large-cutting-height face.

IBEM Simulation of Seismic Wave Scattering by a 3D Tunnel Mountain

The seismic wave scattering by a 3D tunnel mountain is investigated by the indirect boundary element method (IBEM). Without loss of generality, the 3D physical model of hemispherical tunnel mountain in an elastic half-space is established, and the influence of the incidence frequency and angle of P or SV wave on the mountain surface displacements is mainly examined. It is shown that there exists quite a difference between the spatial distribution of displacement amplitude under the incident P wave and the one under SV wave and that the incidence frequency and angle of wave, especially the existence of tunnel excavated in the mountain, have a great effect on the surface displacements of mountain; the presence of the tunnel in the mountain may cause the greater amplification of surface displacement, which is unfavorable to the mountain projects. In addition, it should be noted that the tunnel may suffer the more severe damage under the incident SV wave.

Direct 3D Printing of a hand splint using Reverse Engineering

The present work is focused on the direct manufacturing of a hand splint using free-open access software and a low-cost three-dimensional printer (3DP). The hand digital model was created using panoramic photos by a common mobile phone camera. The photos were used as input to the “3DF-Zephyr” free software for creating the hand surface model. Then, the hand surface model was transferred into the “Autodesk fusion 360” free software and the surface model of the hand splint was generated and modified according to the design requirements. Sequentially, both hand and hand splint were translated to Stereolithography (STL) files and transferred to open access “MakerBot” 3D printing software in order to prepare the G-codes for 3D printing. A low cost 3D printer was used for building the models while Polylactic acid (PLA) was the material of the customized 3D physical models.

Re-interpreting mesenteric vascular anatomy on 3D virtual and/or physical models: positioning the middle colic artery bifurcation and its relevance to surgeons operating colon cancer

BackgroundThe impact of the position of the middle colic artery (MCA) bifurcationand the trajectory of the accessory MCA (aMCA) on adequate lymphadenectomy whenoperating colon cancer have as of yet not been described and/or analysed in theliterature. The aim of this study was to determine the MCA bifurcation position toanatomical landmarks and to assess the trajectory of aMCA.MethodsThe colonic vascular anatomy was manually reconstructed in 3D fromhigh-resolution CT datasets using Osirix MD and 3-matic Medical and analysed. CTdatasets were exported as STL files and supplemented with 3D printed models whenrequired.ResultsThirty-two datasets were analysed. The MCA bifurcation was left to thesuperior mesenteric vein (SMV) in 4 (12.1%), in front of SMV in 17 (53.1%) and rightto SMV in 11 (34.4%) models. Median distances from the MCA origin to bifurcation were3.21 (1.18–15.60) cm. A longer MCA bifurcated over or right to SMV, while a shorterbifurcated left to SMV (r = 0.457, p = 0.009). The main MCA direction was towards right in19 (59.4%) models. When initial directions included left, the bifurcation occurredleft to or anterior to SMV in all models. When the initial directions included right,the bifurcation occurred anterior or right to SMV in all models. The aMCA was foundin 10 (31.3%) models, following the inferior mesenteric vein (IMV) in 5 near thelower pancreatic border. The IMV confluence was into SMV in 18 (56.3%), splenic veinin 11 (34.4%) and jejunal vein in 3 (9.4%) models.ConclusionAwareness of the wide range of MCA bifurcation positions reported iscrucial for the quality of lymphadenectomy performed. The aMCA occurs in 31.3% modelsand its trajectory is in proximity to the lower pancreatic border in one half ofmodels, indicating that it needs to be considered when operating splenic flexurecancer.