Root Geometry Research Articles

New web based event data and geometry visualization for LHCb

The LHCb detector is undergoing a comprehensive upgrade for data taking in the LHC’s Run 3, which is scheduled to begin in 2022. The new Run 3 detector has a different, upgraded geometry and uses new tools for its description, namely DD4hep [2] and ROOT [12]. Besides, the visualization technologies have evolved quite a lot since Run 1, with the introduction of ubiquitous web based solutions or Augmented Reality (AR) for example. The LHCb collaboration has thus started the development of a new visualization solution, based on the Phoenix [6] framework, developed jointly by several experiments in the context of the HEP Software Foundation (HSF) [10]. We present here the architecture and implementation of this new solution, as well as the different contributions made to the Phoenix ecosystem. In particular we discuss a generic tool for exporting ROOT geometries to the visualization application, which can be used to display in a browser either the whole detector or subparts of it. Extensions to the Phoenix visualization primitives regarding calorimeters and performance improvements are also presented.

Planning of graft size and 3D reconstruction using virtual reality technique in aortic valve reimplantation.

To evaluate applicability and feasibility of the virtual imaging technology for diagnosis and planning of the aortic valve sparing procedure. Pre-operative electrocardiography-gated computed tomography images of 12 adult patients with aortic root pathology were used for 3D reconstruction of the aortic root geometry. The structural analysis was conducted with focusing on spatial architecture of key aortic root structures such as the three commissures, intervalvular triangles (IVT), as well as on morphology of the aortic root base (AoB) and of the sinotubular junction (STJ). In all included patients, the 3D mapping of aortic root (AoR) morphology was successfully performed. The pre-operative diameter of the AoB was 30.6 ± 2.6 mm and of the STJ 46.5 ± 7.5 mm (p < 0.001). Based on measured AoB diameter, the mean size of prosthesis used was 28.3 ± 1.37 mm. The planar arrangement of the three commissures was similar to an equilateral triangle where the three commissures were at similar distance for each individual sinus with 39.8 ± 6.64 mm for right, 37.5 ± 7.10 mm for left, and 39.2 ± 7.52 mm for non-coronary sinus (p = 0.72) subsequently. The similar height of the three IVT's with 32.6 ± 5.87 mm for right, 33.6 ± 6.14 mm for anterior, and 31.7 ± 5.83 mm for left IVT (p = 0.73) was suggestive for all three commissures being positioned in the same plane. Consequently at reimplantation, the orientation of the three commissures followed the pattern of an equilateral triangle. The reconstructed images revealed a detailed 3D anatomy of the aortic root, with the spatial arrangement of the intervalvular triangles, planimetric orientation of the commissures, as well as determination of the AoB and STJ diameters. Obtained information was successfully applied to pre-operative surgical planning. The reimplantation technique, the height of the reimplanted intervalvular triangles, as well as their orientation are crucial for achieving adequate aortic valve function.

Modelling of Flow Characteristics of Main Rotor with Elliptical Root Section in Hover Mode

The modelling of a helicopter main rotor flow field in hover regime is being considered. The aerodynamic and aeroacoustics characteristics of two rotor models with different blade root geometries are compared. The first rotor has the shape of NACA0012 air foil in the root section of the blades. The second rotor model has an elliptic air foil in the root of the rotor blade. The amplitude and temporal characteristics of the aeroacoustics emission in near-field are investigated using Computational Fluid Dynamics (CFD).

Research on root appearance and fatigue life of steel catenary riser (SCR) using GMAW/GTAW-P double-sided root welding process

A steel catenary riser (SCR) is a flexible stand-up pipe that connects a subsea wellhead in the seabed (normally at a depth of more than 1500 m) to a floating platform. Waves, ocean currents, and winds apply substantial loads to SCRs that produce fatigue damage. Hence, the requirements for the appearance of SCR weld joints, particularly the weld root, are extremely strict. This paper proposes a new gas metal arc welding/pulse gas tungsten arc welding (GMAW/GTAW-P) double-sided root welding process for SCRs to obtain a nearly smooth root geometry. Test results show that the average values of root reinforcement, root transition angle, and transition radius achieved with this root welding process are only 169 μm, 6.4°, and 4055 μm, respectively. These values are dramatically lower than those achievable with the best technologies available, such as the surface tension transfer (STT) root welding process and cold metal transfer (CMT) root welding process. The fatigue strength of the double-sided welding joints is improved by at least 45.8% because the root stress concentration is significantly reduced. However, incomplete penetration defects were found when the molten pool position was not appropriate. Solutions for this problem are discussed. The proposed process is believed to be a potential strategy for welding high fatigue life SCRs.

Fatigue Strength Assessment of Single-Sided Girth Welds in Offshore Pipelines Subjected to Start-Up and Shut-Down Cycles

During the service life of offshore pipelines, many start-up and shut-down cycles take place, possibly leading to significant cyclic loads. Fatigue failure may occur, resulting in serious environmental pollution and loss of property. The study aims to assess the fatigue strength of single-sided girth welds in offshore pipelines under these specific fatigue loads. The longitudinal stress range caused by the variation of the pipeline’s internal pressure and temperature is calculated. The effective notch strain approach is used to assess the fatigue strength of welds. The plastic behaviour of the weld root is investigated for a study case to justify the use of low-cycle fatigue assessment approaches. The effect of weld root geometry on the notch stress factor is studied to identify the dominant geometrical parameters. The fatigue strength of the study case is assessed, and some limitations of the assessment are discussed. The results show that the plastic behaviour of the weld root is only significant for severe local stress concentrations, which is mainly governed by the axial misalignment, weld root angle and the weld root bead width. If the fatigue damage at failure is 0.1, a limited number of start-up and shut-down cycles are allowed during the service life of the pipeline for the study case, indicating the necessity of fatigue strength assessment.

Tree Information Modeling: A Data Exchange Platform for Tree Design and Management

Trees integrated into buildings and dense urban settings have become a trend in recent years worldwide. Without a thoughtful design, conflicts between green and gray infrastructures can take place in two aspects: (1) tree crown compete with living space above ground; (2) built underground environment, the other way round, affect tree’s health and security. Although various data about urban trees are collected by different professions for multiple purposes, the communication between them is still limited by unmatched scales and formats. To address this, tree information modeling (TIM) is proposed in this study, aiming at a standardized tree description system in a high level of detail (LoD). It serves as a platform to exchange data and share knowledge about tree growth models. From the perspective of architects and landscape designers, urban trees provide ecosystem services (ESS) not only through their overall biomass, shading, and cooling. They are also related to various branching forms and crown density, forming new layers of urban living space. So, detailed stem, branch and even root geometry is the key to interacting with humans, building structures and other facilities. It is illustrated in this paper how these detailed data are collected to initialize a TIM model with the help of multiple tools, how the topological geometry of stem and branches in TIM is interpreted into an L-system (a common syntax to describe tree geometries), allowing implementation of widely established tree simulations from other professions. In a vision, a TIM-assisted design workflow is framed, where trees are regularly monitored and simulated under boundary conditions to approach target parameters by design proposals.

A new proof on the root geometry of Hurwitz-symmetric polynomials

A new proof on the root geometry of Hurwitz-symmetric polynomials

Convex subspaces of Lie incidence geometries

We classify the convex subspaces of all hexagonic Lie incidence geometries (among which all long root geometries of spherical Tits-buildings). We perform a similar classification for most other Lie incidence geometries of spherical Tits-buildings, in particular for all projective and polar Grassmannians, and for exceptional Grassmannians of diameter at most 3.Mathematics Subject Classifications: 51E24Keywords: Buildings, parapolar spaces, long root geometries, hexagonal Lie incidence geometries

Biomechanical Comparison of Six Different Root-Analog Implants and the Conventional Morse Taper Implant by Finite Element Analysis.

Taper implants differ greatly from anatomical teeth in shape. In this study, seven three-dimensional finite element models were established, including a conventional taper implant and six root-analog implants with different root numbers and shapes. Vertical, horizontal, and oblique instantaneous loads of 100 N were applied to the models to obtain stress distribution in the implant, mucosa, cortical bone, and cancellous bone. ANSYS was used to perform the analysis under hypothetical experimental conditions. We find the stresses in all the implants and surrounding tissues varied by loading direction, the sequence of stress magnitude is vertical load, oblique load, and then horizontal load. The maximum stress values in root-analog implants were significantly less than in the taper implant. Moreover, stress distribution in the former was equalized contrary to the concentrated stress in the latter. Root-analog implants with different root geometry also revealed a pattern: stresses in multiple-root implant models were lower than those in single-root implants under the same load. The implant with a long and rounded root distributed the stress more uniformly, and it was mainly concentrated on the implant itself and cancellous bone. However, the opposite effect was observed in the short implant on mucosa and cortical bone. The root geometry of anatomical teeth can modify their functions. A uniform-shaped implant can hardly meet their functional requirements. Thus, the root-analog implant could be a possible solution.

Optimisation of wheelset maintenance by using a reduced flange wear wheel profile

This paper investigates whether it is possible to develop a wheel profile design that will extend wheelset life compared to an existing commonly used Great Britain passenger wheel profile, the P8. The P8 wheel profile was originally developed in the late 1960s as an alternative to a 1:20 coned wheel profile (the P1). The P1 often required frequent turning as the conicity could increase quickly over time as the wheel wore in service. The P8 was designed based on an average worn shape of a P1 wheel. The P8 was found to stay closer to its original shape as it wore in service. However, new P8 wheels or newly profiled P8 wheels tend to experience a high initial flange wear rate in the first 20,000–30,000 miles, until the worn wheel shape reaches ‘dimensional stability’; after this, the flange width typically remains relatively constant. A ‘Reduced Flange Wear’ (RFW) wheel profile has been developed, based on the P8 profile but with a modified flange root geometry. The Wheel Profile Damage Model has been used to calculate how the proposed RFW wheel profile could reduce wear rates and therefore increase wheelset life. This paper presents results for a typical electric multiple unit train (EMU1) running on rural and suburban routes and a higher speed variant (EMU2) running on an inter-city route. The effect of the proposed RFW profile on rail rolling contact fatigue (RCF) has also been evaluated using the Whole Life Rail Model, for the same routes. The results suggest that the proposed RFW profile does reduce flange wear compared to a P8, with larger reductions achieved on routes that are more curvaceous. For wheel turning based purely on restoring wheel profile geometry, the RFW profile could half the amount of material removed at each turning (based on turning wheels at 250,000 miles). Furthermore, the results show that the RFW profile experiences slightly less wheel RCF damage than the P8. When new, the RFW profile appears to cause slightly higher rail RCF than a new P8 (For radii 700 m &lt; R &lt; 1300 m); however, the results suggest that worn RFW profiles cause very similar rail RCF to that caused by worn P8 wheels.

Patient-specific multi-scale design optimization of transcatheter aortic valve stents

Background and ObjectiveTranscatheter aortic valve implantation (TAVI) has become the standard treatment for a wide range of patients with aortic stenosis. Although some of the TAVI post-operative complications are addressed in newer designs, other complications and lack of long-term and durability data on the performance of these prostheses are limiting this procedure from becoming the standard for heart valve replacements. The design optimization of these devices with the finite element and optimization techniques can help increase their performance quality and reduce the risk of malfunctioning. Most performance metrics of these prostheses are morphology-dependent, and the design and the selection of the device before implantation should be planned for each individual patient. MethodsIn this study, a patient-specific aortic root geometry was utilized for the crimping and implantation simulation of 50 stent samples. The results of simulations were then evaluated and used for developing regression models. The strut width and thickness, the number of cells and patterns, the size of stent cells, and the diameter profile of the stent were optimized with two sets of optimization processes. The objective functions included the maximum crimping strain, radial strength, anchorage area, and the eccentricity of the stent. ResultsThe optimization process was successful in finding optimal models with up to 40% decrease in the maximum crimping strain, 261% increase in the radial strength, 67% reduction in the eccentricity, and about an eightfold increase in the anchorage area compared to the reference device. ConclusionsThe stents with larger distal diameters perform better in the selected objective functions. They provide better anchorage in the aortic root resulting in a smaller gap between the device and the surrounding tissue and smaller contact pressure. This framework can be used in designing patient-specific stents and improving the performance of these devices and the outcome of the implantation process.

Rapid hob tip corner optimization of spur gears for increasing bending strength

Spur gears are widely applied in transmissions of heavy load cases, such as turbines, ships, mining devices, and other industrial applications. Increasing the tooth root bending strength offers great potential to increase the power density of gearboxes. To obtain a higher bending strength without increasing manufacturing costs, this study intends to find an optimal tooth root contour by optimizing the hob tip corner geometry. A rapid optimization method is thus proposed, consisting of a quick hobbing simulation to generate the tooth root fillet for arbitrary hob tip corners, a fast meshing adaptation mapping rule to guarantee the high mesh quality of different gear tooth geometries, and an analytical equation for calculating the maximum principal stress of the tooth root margin. The results show that the computing time only takes 5–8 min for each optimization, and an average potential of 15% is obtained for various gear parameters. Furthermore, a unified optimal hob tip contour, suitable for a wide range of gears, is also found with an average optimization potential of 13%. This study contributes greatly to the rapid optimization of the tooth root geometry and the corresponding hob tip geometry for high bending strength.

Long-term Surgical Outcomes of Supravalvar Aortic Stenosis: Modified Simple Sliding Aortoplasty

This study investigated long-term outcomes and factors associated with reoperations in patients who underwent surgical repair of congenital supravalvar aortic stenosis (SVAS). A total of 39 consecutive patients who underwent congenital SVAS repair from 1999 through 2018 were included. Aortic root geometry was evaluated by measuring the ratio of the sinotubular junction diameter to the aortic annulus diameter (STJ/AVA) on echocardiography and proportion of intercommissural distance (ICD) of each sinus on computed tomography. The median age and weight at the time of operation were 4.3 years and 16.9 kg, respectively. Williams syndrome was associated in 25 patients (64.1%). Modified simple sliding aortoplasty (MSSA) was mostly used (n = 35, 89.7%). The median follow-up duration was 9.5 years. There were no early deaths and 1 late death. Overall survival rate was 97.0% at 15 years. There were 7 reoperations during follow-up. Freedom from reoperation for left ventricular outflow tract obstruction and all-cause reoperation were 91.9% and 80.4%, respectively. Age younger than 2 years at initial repair were associated with all-cause reoperation in the univariable analysis. In 35 patients who underwent MSSA, the degree of aortic regurgitation was equal to or less than mild in all patients during follow-up. Their median STJ/AVA on postoperative echocardiography was 0.95 (0.84-1.02). SVAS repair with MSSA provided excellent long-term survival with well-preserved aortic valve competence. Age younger than 2 years at initial repair might be associated with reoperation.

Buildings of exceptional type in buildings of type $\mathsf{E_7}$

We investigate the possible ways in which a thick metasymplectic space $\Gamma$, that is, a Lie incidence geometry of type $\mathsf{F_{4,1}}$ (or $\mathsf{F_{4,4}}$), is embedded into the long root geometry $\Delta$ related to any building of type $\maths

Reverse Engineering in Modeling Agricultural Products

Abstract The purpose of the study was to use reverse engineering to model biological products, especially sugar beet root. In the process of creating the solid model, the appropriate tools available in the 3D design environment were applied. The 3D scan of the beet, in the form of a spatial point cloud, was used to project the root geometry. This was, in turn, used to construct a triangulation grid that includes nodal points of triangles. The subsequent steps presented the process of creating a solid model using the Interpolation Spline tool. Attention has been paid to the possibility of modifying the geometry by inserting additional points into the existing interpolation spline and changing angular position as well as the distance of the structural planes. Geometry mapping error values were determined with regard to the reference model depending on the spread value of the Structural Planes. Error courses are non-linear with a logarithmic line trend (surface field error) and a linear line trend (volume error). The effects demonstrated the usefulness of geometry projection and its applicability to support the strength testing of biological materials, with particular emphasis on dynamic tests using whole roots.

Overview on the fatigue strength of single-sided transverse and longitudinal fillet weld joints

In the present study, an overview on the fatigue performance of single-sided fillet welds is carried out. Both longitudinal load-carrying joints, for instance existing in beam structures and welded hollow sections, and transverse joints are considered in this work. Experimental data of such joints made of mild and ultra-high-strength steel (UHSS) is extracted from existing studies to evaluate the fatigue strength properties. The main characteristics affecting fatigue strength properties of these joints are discussed. Furthermore, the paper evaluates the fatigue strength of single-sided fillet weld joints in comparison with the joints with double-sided welds. The experimental results indicate that in the transverse welds, an increase in material’s yield strength shows a slight decrease in fatigue strength compared to mild steels, while in the longitudinal load-carrying seams, in the case of continuous weld root geometry, high fatigue strength can be achieved with UHSS materials. The double-sided welds provide one FAT class higher fatigue strength for transverse non-load-carrying joints, obtained in terms of mean fatigue strengths. In addition, in transverse joint configurations, intermediate welding was found to have no detrimental effect on the fatigue performance compared to the joints with continuous welds. In longitudinal load-carrying joints, double-sided welds do not provide any additional benefit unless full penetration and, thus, continuous longitudinal weld root shape is achieved with such weld preparation.

TopoRoot: a method for computing hierarchy and fine-grained traits of maize roots from 3D imaging

Background3D imaging, such as X-ray CT and MRI, has been widely deployed to study plant root structures. Many computational tools exist to extract coarse-grained features from 3D root images, such as total volume, root number and total root length. However, methods that can accurately and efficiently compute fine-grained root traits, such as root number and geometry at each hierarchy level, are still lacking. These traits would allow biologists to gain deeper insights into the root system architecture.ResultsWe present TopoRoot, a high-throughput computational method that computes fine-grained architectural traits from 3D images of maize root crowns or root systems. These traits include the number, length, thickness, angle, tortuosity, and number of children for the roots at each level of the hierarchy. TopoRoot combines state-of-the-art algorithms in computer graphics, such as topological simplification and geometric skeletonization, with customized heuristics for robustly obtaining the branching structure and hierarchical information. TopoRoot is validated on both CT scans of excavated field-grown root crowns and simulated images of root systems, and in both cases, it was shown to improve the accuracy of traits over existing methods. TopoRoot runs within a few minutes on a desktop workstation for images at the resolution range of 400^3, with minimal need for human intervention in the form of setting three intensity thresholds per image.ConclusionsTopoRoot improves the state-of-the-art methods in obtaining more accurate and comprehensive fine-grained traits of maize roots from 3D imaging. The automation and efficiency make TopoRoot suitable for batch processing on large numbers of root images. Our method is thus useful for phenomic studies aimed at finding the genetic basis behind root system architecture and the subsequent development of more productive crops.

The Virtual Root : Mathematical Modeling of Auxin Transport in the Arabidopsis Root Tip Using the Open-Source Software SimuPlant.

Hormone signals like auxin play a critical role controlling plant growth and development. Determining the mechanisms that regulate auxin distribution in cells and tissues is a vital step in understanding this hormone's role during plant development. Recent mathematical models have enabled us to understand the essential role that auxin influx and efflux carriers play in auxin transport in the Arabidopsis root tip (Band et al., Plant Cell 26(3):862-875, 2014; Grieneisen et al., Nature 449(7165):1008-1013, 2007; van den Berg et al., Development 143(18):3350-3362, 2016). In this chapter, we describe SimuPlant: The Virtual Root (SimuPlant, University of Nottingham. https://www.simuplant.org/ . Accessed 20 Sept 2019); an open source software suite, built using the OpenAlea (Pradal et al., Funct Plant Biol 35(10):751-760, 2008) framework, that is designed to simulate vertex-based models in real plant tissue geometries. We provide guidance on how to install SimuPlant, run 2D auxin transport models in the Arabidopsis root tip, manipulate parameters, and visualize model outputs.SimuPlant features a graphical user interface (GUI) designed to allow users with no programming experience to simulate auxin dynamics within the Arabidopsis root tip. Within the user interface, users of SimuPlant can select from a range of model assumptions and can choose to manipulate model and simulation parameter values. Users can then investigate how their choices affect the predicted distribution of auxin in the Arabidopsis root tip. The results of the model simulations are shown visually within the root geometry and can be exported and saved as PNG image files.

On the weld root fatigue strength and improvement techniques for non-load-carrying transverse attachment joints with single-sided fillet welds and made of mild and ultra-high-strength steels

The present study experimentally and numerically investigates the fatigue strength of non-load-carrying transverse attachment joints prepared with single-sided fillet weld. Constant amplitude fatigue tests are carried out on specimens made of S355 and S1100 steel grades to obtain the fatigue strength of these joints. In addition, the study evaluates fatigue life improvement technique for these joints comprising the use of a curved plate edge shape in the attachment, which results in varying weld penetration and weaved weld root shape. Numerical analyses are carried out to determine the applicability of the effective notch stress concept in assessing the fatigue strength of the studied joints. The experimental results show that the weld root to the base plate is the critical fatigue failure mechanism, and characteristic design fatigue strengths of FAT97.7% = 109 MPa and FAT97.7% = 97 MPa (with a slope parameter of m = 3) in the nominal stress system for the S355 and S1100 grades with a straight root geometry are obtained, respectively. Using a curved plate edge shape and varying weld penetration, the fatigue strength could be improved by up to 25% for the S1100 grade. The numerical analyses reveal that the effective notch stress modeling technique of the fictitious notch radius significantly affects the stress concentration factors, while the fillet-type modeling technique at the weld root showed more accurate results than the keyhole shape.

Contributions towards Data driven Deep Learning methods to predict Steady State Fluid Flow in mechanical Heart Valves

Abstract It is commonly accepted that hemodynamic situation is related with cardiovascular diseases as well as clinical post-procedural outcome. In particular, aortic valve stenosis and insufficiency are associated with high shear flow and increased pressure loss. Furthermore, regurgitation, high shear stress and regions of stagnant blood flow are presumed to have an impact on clinical result. Therefore, flow field assessment to characterize the hemodynamic situation is necessary for device evaluation and further design optimization. In-vitro as well as in-silico fluid mechanics methods can be used to investigate the flow through prostheses. In-silico solutions are based on mathematical equitation’s which need to be solved numerically (Computational Fluid Dynamics - CFD). Fundamentally, the flow is physically described by Navier-Stokes. CFD often requires high computational cost resulting in long computation time. Techniques based on deep-learning are under research to overcome this problem. In this study, we applied a deep-learning strategy to estimate fluid flows during peak systolic steady-state blood flows through mechanical aortic valves with varying opening angles in randomly generated aortic root geometries. We used a data driven approach by running 3,500 two dimensional simulations (CFD). The simulation data serves as training data in a supervised deep learning framework based on convolutional neural networks analogous to the U-net architecture. We were able to successfully train the neural network using the supervised data driven approach. The results showing that it is feasible to use a neural network to estimate physiological flow fields in the vicinity of prosthetic heart valves (Validation error below 0.06), by only giving geometry data (Image) into the Network. The neural network generates flow field prediction in real time, which is more than 2500 times faster compared to CFD simulation. Accordingly, there is tremendous potential in the use of AIbased approaches predicting blood flows through heart valves on the basis of geometry data, especially in applications where fast fluid mechanic predictions are desired.