3D Geometric Model Research Articles

3D multiphysics model for the simulation of electrochemical machining of stainless steel (SS316)

In electrochemical machining (ECM)—a method that uses anodic dissolution to remove metal—it is extremely difficult to predict material removal and resulting surface finish due to the complex interaction between the numerous parameters available in the machining conditions. In this paper, it is argued that a 3D coupled multiphysics finite element model is a suitable way to further develop the ability to model the ECM process. This builds on the work of previous researchers and further claims that the overpotential available at the surface of the workpiece is a crucial factor in ensuring satisfactory results. As a validation example, a real-world problem for polishing via ECM of SS316 pipes is modelled and compared to empirical tests. Various physical and chemical effects, including those due to electrodynamics, fluid dynamic, and thermal and electrochemical phenomena, were incorporated in the 3D geometric model of the proposed tool, workpiece, and electrolyte. Predictions were made for current density, conductivity, fluid velocity, temperature, and crucially, with estimates of the deviations in overpotential. Results revealed a good agreement between simulation and experiment and these were sufficient not only to solve the immediate real problem presented but also to ensure that future additions to the technique could in the longer term lead to a better means of understanding a most useful manufacturing process.

Modeling, validation and verification of three-dimensional cell-scaffold contacts from terabyte-sized images

BackgroundCell-scaffold contact measurements are derived from pairs of co-registered volumetric fluorescent confocal laser scanning microscopy (CLSM) images (z-stacks) of stained cells and three types of scaffolds (i.e., spun coat, large microfiber, and medium microfiber). Our analysis of the acquired terabyte-sized collection is motivated by the need to understand the nature of the shape dimensionality (1D vs 2D vs 3D) of cell-scaffold interactions relevant to tissue engineers that grow cells on biomaterial scaffolds.ResultsWe designed five statistical and three geometrical contact models, and then down-selected them to one from each category using a validation approach based on physically orthogonal measurements to CLSM. The two selected models were applied to 414 z-stacks with three scaffold types and all contact results were visually verified. A planar geometrical model for the spun coat scaffold type was validated from atomic force microscopy images by computing surface roughness of 52.35 nm ±31.76 nm which was 2 to 8 times smaller than the CLSM resolution. A cylindrical model for fiber scaffolds was validated from multi-view 2D scanning electron microscopy (SEM) images. The fiber scaffold segmentation error was assessed by comparing fiber diameters from SEM and CLSM to be between 0.46% to 3.8% of the SEM reference values. For contact verification, we constructed a web-based visual verification system with 414 pairs of images with cells and their segmentation results, and with 4968 movies with animated cell, scaffold, and contact overlays. Based on visual verification by three experts, we report the accuracy of cell segmentation to be 96.4% with 94.3% precision, and the accuracy of cell-scaffold contact for a statistical model to be 62.6% with 76.7% precision and for a geometrical model to be 93.5% with 87.6% precision.ConclusionsThe novelty of our approach lies in (1) representing cell-scaffold contact sites with statistical intensity and geometrical shape models, (2) designing a methodology for validating 3D geometrical contact models and (3) devising a mechanism for visual verification of hundreds of 3D measurements. The raw and processed data are publicly available from https://isg.nist.gov/deepzoomweb/data/ together with the web -based verification system.

Limit analysis of complex welds between plasma vessel and ports in W7-X cryostat system

Wendelstein 7-X (W7-X) is an experimental modular stellarator of the HELIAS type, currently in the second phase of operation in Greifswald, Germany. The stellarator is a complex 3D structure with high level safety requirements. As a result, sophisticated methods are necessary for the analysis of critical components and it is very important to evaluate structural strength of the welded connections between the plasma vessel and the ports.The structural integrity analysis of the welded connection between plasma vessel and ports has been performed for several critical and/or representative port welds. The modelling of the welded connection was performed in two steps. First the geometrical 3D models of these port welds were prepared using the SolidWorks software. The model of a welded connection of the complex shape was modelled by creating a big number of sketches around the perimeter of the port-to-PV connection. Later, the sketches were connected using a loft feature and was transferred to the ABAQUS/Standard FE software. The limit analysis by means of finite element method (ABAQUS code) was used to confirm static strength reliability of port welds. According to the results of the analysis it is possible to conclude that the proposed welding between the plasma vessel and the analysed ports fully meets the structural requirements.

Validation of the Gatortail method for accurate sizing of pulmonary vessels from 3D medical images.

Detailed characterization of changes in vessel size is crucial for the diagnosis and management of a variety of vascular diseases. Because clinical measurement of vessel size is typically dependent on the radiologist's subjective interpretation of the vessel borders, it is often prone to high inter- and intra-user variability. Automatic methods of vessel sizing have been developed for two-dimensional images but a fully three-dimensional (3D) method suitable for vessel sizing from volumetric X-ray computed tomography (CT) or magnetic resonance imaging has heretofore not been demonstrated and validated robustly. In this paper, we refined and objectively validated Gatortail, a method that creates a mathematical geometric 3D model of each branch in a vascular tree, simulates the appearance of the virtual vascular tree in a 3D CT image, and uses the similarity of the simulated image to a patient's CT scan to drive the optimization of the model parameters, including vessel size, to match that of the patient. The method was validated with a 2-dimensional virtual tree structure under deformation, and with a realistic 3D-printed vascular phantom in which the diameter of 64 branches were manually measured 3 times each. The phantom was then scanned on a conventional clinical CT imaging system and the images processed with the in-house software to automatically segment and mathematically model the vascular tree, label each branch, and perform the Gatortail optimization of branch size and trajectory. Previously proposed methods of vessel sizing using matched Gaussian filters and tubularity metrics were also tested. The Gatortail method was then demonstrated on the pulmonary arterial tree segmented from a human volunteer's CT scan. The standard deviation of the difference between the manually measured and Gatortail-based radii in the 3D physical phantom was 0.074mm (0.087 in-plane pixel units for image voxels of dimension 0.85×0.85×1.0mm) over the 64 branches, representing vessel diameters ranging from 1.2 to 7mm. The linear regression fit gave a slope of 1.056 and an R2 value of 0.989. These three metrics reflect superior agreement of the radii estimates relative to previously published results over all sizes tested. Sizing via matched Gaussian filters resulted in size underestimates of >33% over all three test vessels, while the tubularity-metric matching exhibited a sizing uncertainty of >50%. In the human chest CT data set, the vessel voxel intensity profiles with and without branch model optimization showed excellent agreement and improvement in the objective measure of image similarity. Gatortail has been demonstrated to be an automated, objective, accurate and robust method for sizing of vessels in 3D non-invasively from chest CT scans. We anticipate that Gatortail, an image-based approach to automatically compute estimates of blood vessel radii and trajectories from 3D medical images, will facilitate future quantitative evaluation of vascular response to disease and environmental insult and improve understanding of the biological mechanisms underlying vascular disease processes.

Impact of Patient-Specific Inflow Velocity Profile on Hemodynamics of the Thoracic Aorta.

Computational fluid dynamics (CFD) provides a noninvasive method to functionally assess aortic hemodynamics. The thoracic aorta has an anatomically complex inlet comprising of the aortic valve and root, which is highly prone to different morphologies and pathologies. We investigated the effect of using patient-specific (PS) inflow velocity profiles compared to idealized profiles based on the patient's flow waveform. A healthy 31 yo with a normally functioning tricuspid aortic valve (subject A), and a 52 yo with a bicuspid aortic valve (BAV), aortic valvular stenosis, and dilated ascending aorta (subject B) were studied. Subjects underwent MR angiography to image and reconstruct three-dimensional (3D) geometric models of the thoracic aorta. Flow-magnetic resonance imaging (MRI) was acquired above the aortic valve and used to extract the patient-specific velocity profiles. Subject B's eccentric asymmetrical inflow profile led to highly complex velocity patterns, which were not replicated by the idealized velocity profiles. Despite having identical flow rates, the idealized inflow profiles displayed significantly different peak and radial velocities. Subject A's results showed some similarity between PS and parabolic inflow profiles; however, other parameters such as Flowasymmetry were significantly different. Idealized inflow velocity profiles significantly alter velocity patterns and produce inaccurate hemodynamic assessments in the thoracic aorta. The complex structure of the aortic valve and its predisposition to pathological change means the inflow into the thoracic aorta can be highly variable. CFD analysis of the thoracic aorta needs to utilize fully PS inflow boundary conditions in order to produce truly meaningful results.

Coupled in silico platform: Computational fluid dynamics (CFD) and physiologically-based pharmacokinetic (PBPK) modelling

One of the critical components of the respiratory drug delivery is the manner in which the inhaled aerosol is deposited in respiratory tract compartments. Depending on formulation properties, device characteristics and breathing pattern, only a certain fraction of the dose will reach the target site in the lungs, while the rest of the drug will deposit in the inhalation device or in the mouth–throat region. The aim of this study was to link the Computational fluid dynamics (CFD) with physiologically-based pharmacokinetic (PBPK) modelling in order to predict aerolisolization of different dry powder formulations, and estimate concomitant in vivo deposition and absorption of amiloride hydrochloride. Drug physicochemical properties were experimentally determined and used as inputs for the CFD simulations of particle flow in the generated 3D geometric model of Aerolizer® dry powder inhaler (DPI). CFD simulations were used to simulate air flow through Aerolizer® inhaler and Discrete Phase Method (DPM) was used to simulate aerosol particles deposition within the fluid domain. The simulated values for the percent emitted dose were comparable to the values obtained using Andersen cascade impactor (ACI). However, CFD predictions indicated that aerosolized DPI have smaller particle size and narrower size distribution than assumed based on ACI measurements. Comparison with the literature in vivo data revealed that the constructed drug-specific PBPK model was able to capture amiloride absorption pattern following oral and inhalation administration. The PBPK simulation results, based on the CFD generated particle distribution data as input, illustrated the influence of formulation properties on the expected drug plasma concentration profiles. The model also predicted the influence of potential changes in physiological parameters on the extent of inhaled amiloride absorption. Overall, this study demonstrated the potential of the combined CFD-PBPK approach to model inhaled drug bioperformance, and suggested that CFD generated results might serve as input for the prediction of drug deposition pattern in vivo.

Analysis of non-Newtonian effects within an aorta-iliac bifurcation region

The geometry of the arteries at or near arterial bifurcation influences the blood flow field, which is an important factor affecting arteriogenesis. The blood can act sometimes as a non-Newtonian fluid. However, many studies have argued that for large and medium arteries, the blood flow can be considered to be Newtonian. In this work a comprehensive investigation of non-Newtonian effects on the blood fluid dynamic behavior in an aorta-iliac bifurcation is presented. The aorta-iliac geometry is reconstructed with references to the values reported in Shah et al. (1978); the 3D geometrical model consists of three filleted cylinders of different diameters. Governing equations with the appropriate boundary conditions are solved with a finite-element code. Different rheological models are used for the blood flow through the lumen and detailed comparisons are presented for the aorta-iliac bifurcation. Results are presented in terms of the velocity profiles in the bifurcation zone and Wall Shear Stress (WSS) for different sides of the bifurcation both for male and female geometries, showing that the Newtonian fluid assumption can be made without any particular loss in terms of accuracy with respect to the other more complex rheological models.

Modeling curve dynamics and spatial geometry characteristics of rice leaves

AbstractThe objective of this work was to develop a dynamic model for describing leaf curves and a detailed spatial geometry model of the rice leaf (including sub-models for unexpanded leaf blades, expanded leaf blades, and leaf sheaths), and to realize three-dimensional (3D) dynamic visualization of rice leaves by combining relevant models. Based on the experimental data of different cultivars and nitrogen (N) rates, the time-course spatial data of leaf curves on the main stem were collected during the rice development stage, then a dynamic model of the rice leaf curve was developed using quantitative modeling technology. Further, a detailed 3D geometric model of rice leaves was built based on the spatial geometry technique and the non-uniform rational B-spline (NURBS) method. Validating the rice leaf curve model with independent field experiment data showed that the average distances between observed and predicted curves were less than 0.89 and 1.20 cm at the tilling and jointing stages, respectively. The proposed leaf curve model and leaf spatial geometry model together with the relevant previous models were used to simulate the spatial morphology and the color dynamics of a single leaf and of leaves on the rice plant after different growing days by 3D visualization technology. The validation of the leaf curve model and the results of leaf 3D visualization indicated that our leaf curve model and leaf spatial geometry model could efficiently predict the dynamics of rice leaf spatial morphology during leaf development stages. These results provide a technical support for related research on virtual rice.

Improving building energy modelling by applying advanced 3D surveying techniques on agri-food facilities

Food industry is the production sector with the highest energy consumption. In Europe, the energy used to produce food accounts for 26% of total energy consumption. Over 28% is used in industrial processes. Recently, European food companies have increased their efforts to make their production processes more sustainable, also by giving preference to the use of renewable energy sources. In Italy, the total energy consumption in agriculture and food sectors decreased between 2013 and 2014, passing from 16.79 to 13.3 Mtep. Since energy consumption in food industry is nearly twice the one in agriculture (8.57 and 4.73 Mtep, respectively), it is very important to improve energy efficiency and use green technologies in all the phases of food processing and conservation. In Italy, a recent law (Legislative Decree 102, 04/07/2014) has made energy-use diagnosis compulsory for all industrial concerns, particularly for those showing high consumption levels. In the case of food industry buildings, energy is mainly used for indoor microclimate control, which is needed to ensure workers’ wellbeing and the most favourable conditions for food processing and conservation. To this end, it is important to have tools and methods allowing for easy, rapid and precise energy performance assessment of agri-food buildings. The accuracy of the results obtainable from the currently available computational models depends on the grade of detail and information used in constructional and geometric modelling. Moreover, this phase is probably the most critical and time-consuming in the energy diagnosis. In this context, fine surveying and advanced 3D geometric modelling procedures can facilitate building modelling and allow technicians and professionals in the agri-food sector to use highly efficient and accurate energy analysis and evaluation models. This paper proposes a dedicated model for energy performance assessment in agri-food buildings. It also shows that using advanced surveying techniques, such as a terrestrial laser scanner and an infrared camera, it is possible to create a three-dimensional parametric model, while, thanks to the heat flow meter Accepted paper measurement method, it is also possible to obtain a thermophysical model. This model allows assessing the energy performance of agri-food buildings in order to improve the indoor microclimate control and the conditions of food processing and conservation.

Doppler Shift and Capacity Analysis of MIMO Antenna Arrays in a Novel 3D Geometric Channel Model

One of the fundamental research areas in wireless communications is the development of realistic models that can efficiently and accurately describe the wireless propagation channel. In multi-path environments, the received signal frequency constantly varies as a result of the relative motion between the receiver and transmitter. In this paper, we bridged a novel 3D geometric channel model and the multiple-input and multiple-output (MIMO) antenna array, analyzed deeply the probability density functions (PDFs) of the Doppler shift (DS), its variance, and characteristic function and etc. For the particular channel model, analytical expressions for PDFs of the channel model and the DS of mobile station (MS) due to its motion, have been derived. Based on the analysis, we investigated MIMO receiving performance. Also developed a geometric channel model, and was firstly in the asymmetric geometry literature due to a directional antenna array employed at base station. For this channel model, it was assumed that each multi-path component of the propagating signal undergoes one bounce. It was also assumed that the scattering objects around MS, could be expressed as Gaussian and exponential density models, which are more suitable to simulate outdoor and indoor environments.

The process of designing a rotating platform artificial knee prosthesis with posterior stabilizers by finite element analysis

The purpose of this paper is to design a rotating platform knee prosthesis with posterior stabilizers. This design is based on reverse engineering and interactive acquisition and reconstruction of 3D models combined with the finite element method. A 3D geometric model of a healthy knee joint was created from an anatomical knee model by using an active acquisition system based on a 3D scanner. This healthy model comprises a portion of the long bones (femur, tibia and fibula), as well as the transverse ligament, medial collateral ligament, posterior cruciate ligament, anterior cruciate ligament, medial meniscus and cartilage. The digital model that was obtained was repaired and converted to an engineering drawing format by use of CATIA© software. Also, based on the foregoing format, a rotating platform knee prosthesis was designed and assembled by this software. Once the healthy and artificial models were repaired, the Mentat Marc© software was used to develop the healthy and artificial knee FE models. From the anthropometry of the human body, a combination of loads and positions were obtained by use of 3D Static Strength Prediction software. The normal stresses, Von Mises stresses and all relative displacements of the healthy and artificial knee FE model were determined. The Von Mises stresses on both the cortical and the trabecular bone of the artificial and healthy knee FE model were analyzed and compared. The prosthesis was designed for the knee of a male patient of height and body weight of 190 cm and 120 kg, respectively.

Medial Proximal Femoral Angle better than Neck-Shaft Angle? Influence of Rotation on the Anteroposterior Radiograph

AbstractNeck-shaft angle (NSA) and medial proximal femoral angle (MPFA) describe the geometry of the proximal femur, but they are influenced by rotation. The MPFA is closer to the right angle and therefore assumed to be less influenced. This hypothesis was tested with a mathematical approach to compare the effects of rotation and their clinical relevance on both angles. We developed a three-dimensional (3D) geometrical model representing projectional radiography of the femoral axes under rotation and derived a mathematical equation. For validation purposes, we experimentally simulated projectional radiography and compared the results to those of the equation (five different inclinations of the femoral neck (IFN) each in 13 different rotations). The validated equation was used to determine the influence of rotation (–60° to +60°) on normal valued NSA and MPFA. The mean absolute difference between calculated and experimentally measured values was 0.6° (standard deviation [SD] 0.5; 0.0–2.2). The mean calculated difference between true and projected NSA was 7.1° (SD 7.1; 0.0–22.0), and for the MPFA, it was –1.9° (SD 2.2; –7.4 to 0.0). Clinically relevant deviations (≥5°) occurred at ≥30° external or ≥ 40° internal rotation for the NSA, for the MPFA at 60° external rotation. Mathematical modeling of radiographic projection of the IFN is possible to a high level of accuracy. Our results indicate that the NSA is significantly more susceptible to deviations caused by rotation than the MPFA. Clinicians must be aware of rotational influences in radiographic projection and possibly should use the MPFA instead of the NSA. The rotational influence during X-ray imaging must be controlled accurately, and femoral torsion should be quantified in computed tomography/magnetic resonance imaging (CT/MRI) scans if possible. 3-D bone models reconstructed from digital image data can be a future option for measuring true angles. Level of evidence was basic research.

A novel 3D geometrical reconstruction model for porous rocks

In this paper, a novel geometrical reconstruction model is proposed for numerical simulation of pore structure in rocks. The spatial configuration and geometrical information of the microstructure are firstly gathered from Chongqing sandstone by X-ray micro-CT observations, and experimental tests on Chongqing sandstone are applied to obtain the mechanical parameters. Then, on the basis of the gathered geometrical information, the surface geometrical model is established by using the modified Marching cubes algorithm. Next, the established surface geometrical model is extended to 3D tetrahedral model by using Delaunay refinement algorithm. Finally, the 3D tetrahedral model is transformed into finite element (FE) numerical model. Moreover, the relationship between the porosity, fractal dimension of pore structure and mechanical properties of Chongqing sandstone is also investigated. The comparison of the numerical results and the experimental data shows a good consistency.

The method of 3D reconstruction of apple shape. Part 3. Geometric 3D model of an apple using the interpolation function

The method of 3D reconstruction of apple shape. Part 3. Geometric 3D model of an apple using the interpolation function

The method of 3D reconstruction of apple shape. Part 2. Geometric 3D model of an apple using Bézier curves

The method of 3D reconstruction of apple shape. Part 2. Geometric 3D model of an apple using Bézier curves

Angle and time of arrival characteristics of 3D air-to-ground radio propagation environments

A three dimensional (3D) geometric channel model is proposed for ground-to-air (G2A) and air-to-ground (A2G) communication links. A low-elevated ground station (GS) and a high-elevated air station (AS) are taken at foci points of a virtual bounding ellipsoid corresponded from known knowledge of delay of longest propagation path. The effective region of scatterers around the GS is designed on the basis of this ellipsoid truncated by the average rooftop level (or average height of sea waves) and ground plane. Closed-form expressions for joint and marginal probability density functions (PDFs) of angle of arrival (AoA) observed at AS and GS in correspondence with azimuth and elevation angles are derived. Furthermore, closed-form expressions for density of energy with respect to the delay of arriving multipath waves corresponded from both the elevation and azimuth AoA are derived independently when observed from either end of the communication link. Moreover, effect of different physical parameters of the channel on distribution of energy in angular and temporal domains is presented. The comparison of analytical results with results of a notable model is also presented. In order to verify the derived analytical expressions, a comparison of analytical results with the performed simulation results is presented, which shows a good match.

Texture and design of green chip seal using recycled crumb rubber aggregate

The depletion of natural resources forces the construction industry to explore using cleaner recycled material as replacements of virgin construction materials. A new eco-friendly chip seal pavement, in which the mineral aggregate was replaced by crumb rubber obtained from scrap tires, was investigated in this study. A total of 142 chip seal specimens were prepared and tested to investigate the impact of using recycled rubber aggregate on the chip seal's micro and macro texture and their impacts on the skid resistance. The microtexture of the new proposed recycled aggregate was examined using a high-resolution 3D digital microscope. The macrotexture of the new chip seal pavement was examined using image processing and sand patch methods. The skid resistance of the new chip seal under both ambient and elevated temperatures was then explored. Two types of emulsions, two types of asphalt cement binders, two types of mineral aggregate as well as two types of recycled crumb rubber were involved in the examined test matrix. This study concluded that the crumb rubber can be used in the chip seal as partial or full replacement of mineral aggregates. Using crumb rubber has a significant impact on improving both macrotexture and microtexture of chip seal. In addition, the low thermal conductivity of crumb rubber helped the chip seal resist elevated temperature without significant loss in skid resistance. A 3D geometrical model was then proposed to simulate the aggregate embedment so it can be used to design the required binder application rate that provides adequate embedment depth and skid resistance.

Teaching of mechanical engineering concepts through 3D geometric modeling

Teaching of mechanical engineering concepts through 3D geometric modeling

Research on a mobile manipulator for biochemical sampling tasks

PurposeThe paper aims to present a tracked robot comprised of several biochemical sampling instruments and a universal control architecture. In addition, a dynamic motion planning strategy and autonomous modules in sampling tasks are designed and illustrated at length.Design/methodology/approachSeveral sampling instruments with position tolerance and sealing property are specifically developed, and a robotic operation system (ROS)-based universal control architecture is established. Then, based on the system, two typical problems in sampling tasks, i.e. arm motion planning in unknown environment and autonomous modules, are discussed, implemented and tested. Inspired by the idea of Gaussian process classification (GPC) and Gaussian process (GP) information entropy, three-dimensional (3D) geometric modeling and arm obstacle avoidance strategy are implemented and proven successfully. Moreover, autonomous modules during sampling process are discussed and realized.FindingsSmooth implementations of the two experiments justify the validity and extensibility of the robot control scheme. Furthermore, the former experiment proves the efficiency of arm obstacle avoidance strategy, while the later one demonstrates the time reduction and accuracy improvement in sampling tasks as the autonomous actions.Practical implicationsThe proposed control architecture can be applied to more mobile and industrial robots for its feasible and extensible scheme, and the utility function in arm path planning strategy can also be utilized for other information-driven exploration tasks.Originality/valueSeveral specific biochemical sampling instruments are presented in detail, while ROS and Moveit! are integrated into the system scheme, making the robot extensible, achievable and real-time. Based on the control scheme, an information-driven path planning algorithm and automation in sampling tasks are conceived and implemented.

Ni-Fe-Cu-PGE ore deposition driven by metasomatic fluids and melt-rock reactions in the deep crust: The ultramafic pipe of Valmaggia, Ivrea-Verbano, Italy

The Valmaggia ultramafic pipe belongs to a group of Fe-Ni-Cu-PGE-rich, hydrous ultramafic intrusions emplaced within the Ivrea-Verbano Zone (Italy). According to the most recent geodynamic models these early Triassic ultramafic pipes represent a network of magma conduits derived from partial melting of continental lithospheric mantle metasomatized by fluids and melts related to the Eo-Varisican subduction. New extensive mapping and sampling of the Valmaggia pipe provides evidence of the close relationship between metasomatism and Fe-Ni-Cu-PGE mineralization. New geological data allow a 3D geometrical model of the pipe that intrudes the Main Gabbro domain. The pipe has a sub-vertical, tube-like main body with at least three lateral branches. Along its rims the pipe displays magmatic, soft contacts with an almost continuous meter-sized envelope of a peculiar marginal rock facies (“plagioclasite”) consisting of Na-bearing plagioclase, biotite and apatite and, locally, with pegmatoidal texture. The peridotite pipe consists of a primary anhydrous mineral assemblage comprising coarse-grained olivine, diopside, enstatite and Cr-rich spinel. These minerals are extensively overprinted by a metasomatic assemblage comprising Ti-rich pargasitic amphibole and phlogopite oikocrysts, enstatite, Al-rich spinel and PGE-bearing Fe-Ni-Cu sulfides, with accessory carbonates, Cl-F-rich apatite, zircon and monazite. Sulfide mineralization is preferentially located along pipe margins, and, subordinately, in the nearby plagioclasite contact rock. Sulfides are strictly associated with the metasomatic assemblage and occur as disseminated mm-sized droplets, network-like aggregates and cm-sized amoeboidal nodules rimmed by carbonates. Several features suggest that plagioclasite interacted with the ultramafic pipe, and infiltrated it, as a magma. Plagioclasite in contact with the pipe rock frequently displays a mottled texture, similar to that of gabbro, and where dark nodules, with ultramafic cores and pargasite- spinel-phlogopite-bearing symplectite coronas, are densely disseminated in white plagioclasite-rich groundmass. Metasomatic assemblages and symplectite textures, suggesting disequilibrium between pipe minerals and plagioclasite components, are widely developed also along the pipe margins and interstitial plagioclase pockets within the pipe. The metasomatic minerals provide calculated PT conditions ranging between 680° and 870°C and between 4 and 8kbar. Such conditions are compatible with the latest geodynamic model for the Ivrea Zone pipes proposing their emplacement in the lower crust. These PT constraints also likely apply to the conditions of ore deposition because of the strict relationships between the metasomatic assemblage and the sulfides. Carbonate crystals that are associated with sulfide-rich portions of the pipe are likely the product of CO2 vapor sticking to the sulfide melt surface resulting in their net buoyancy and ascent in the melt. The textural and chemical characteristics of the pipe mineral assemblage and sulfide mineralization suggest a polyphasic evolution dominated by metasomatism during interaction between magmas. At Valmaggia the alkali- and volatile-rich, metasomatizing magma may be analogous to slab-derived melts envisaged in the most recent geodynamic model for IVZ. Percolation of a metasomatic melt favours Valmaggia pipe-like geometries, including a tubular main body with lateral appendages.