Layer Geometry Research Articles

Modelling the influence of material and process parameters on Shotcrete 3D Printed strands - cross-section adjustment for automatic robotic manufacturing

Due to its high interlayer strength and application flexibility, Shotcrete 3D Printing (SC3DP) is a promising method for the additive manufacturing of structural concrete components. The printing process is based on a layer-wise material application, conducted along a pre-designed printing path. However, material batch inhomogeneities and environmental alteration lead to varying concrete properties over the production processes. These material irregularities stochastically affect the layer geometry and thus limit the achievable reproducibility and accuracy. To enhance the process stability and improve the dimensional component quality in case of environmental changes, a reliable mapping between the strand geometry and the process and material parameters is fundamental for systematic cross-section adjustment.In this paper, we present an experimental-based approach for attaining a flexible regression model of the cross-section of Shotcrete 3D Printed concrete strands. The width and height of the layer are chosen for the strand representation, which we considered as the main factors for the printing-path planning. Regarding the modelling parameters, we focus on the volume flow parameters of concrete and air, and on the accelerator dosage. These inertia afflicted parameters can provide a consistent strand geometry, while factors of lower latency such as printing speed or spray distance are conserved for online adaptation. Based on the presented proceeding, an adjustable layer height and width model has been successfully used to predict the strand properties. The production of a medium sized sample wall further proves the applicability to the production process. In addition, we demonstrated that the chosen parameters not only affect the geometry but also the mechanical performance of SC3DP-specimens. This is evaluated based on flexural strength measurements. Given the geometrical and mechanical properties, the study defines applicable limits for the investigated parameters.

Atomically engineered cobaltite layers for robust ferromagnetism.

Emergent phenomena at heterointerfaces are directly associated with the bonding geometry of adjacent layers. Effective control of accessible parameters, such as the bond length and bonding angles, offers an elegant method to tailor competing energies of the electronic and magnetic ground states. In this study, we construct unit-thick syntactic layers of cobaltites within a strongly tilted octahedral matrix via atomically precise synthesis. The octahedral tilt patterns of adjacent layers propagate into cobaltites, leading to a continuation of octahedral tilting while maintaining substantial misfit tensile strain. These effects induce severe rumpling within an atomic plane of neighboring layers, further triggering the electronic reconstruction between the splitting orbitals. First-principles calculations reveal that the cobalt ions transit to a higher spin state level upon octahedral tilting, resulting in robust ferromagnetism in ultrathin cobaltites. This work demonstrates a design methodology for fine-tuning the lattice and spin degrees of freedom in correlated quantum heterostructures by exploiting epitaxial geometric engineering.

Pressure control in material extrusion additive manufacturing

This paper discusses the effect called undesirable extrusion dynamics that occur during material extrusion printing or fused deposition modeling. This effect is revealed during high acceleration and deceleration of printing head and results in over-extrusion on corners of parts and printed layer unevenness. To minimize this effect, modern control systems use Advance algorithms for dynamics control. However, such disadvantages as inertia, reduced printing speed, need for manual calibration, as well as uncertainty of the influence of material, nozzle geometry, and printing process parameters on the algorithm performance do not allow this group of solutions to be applied on an industrial scale. The paper presents a study of the influence of printing characteristics, such as material type, extruder type, printing temperature, layer and nozzle geometry, on extrusion dynamics through a series of experiments. The experiments were carried out on a Creality Ender 3 printer. The obtained experimental data will allow us to deepen the understanding of extrusion dynamics influence in FDM printing; they are also used in the present study to modify existing dynamics control algorithms. The paper proposes a modification of Advance algorithm based on machine learning. It is proposed to implement an algorithm containing two trained neural network models. One model predicts changes in printing head motion to minimize residual defects and increase average print speed. The second model predicts the compensation parameter for specific printing conditions without the need for manual calibration. A neural network model was trained to determine the compensation parameter depending on the type of material, layer thickness, nozzle geometry and printing temperature. The model was trained based on experimental data. The developed algorithm was introduced into Linear Advance algorithm of the Marlin firmware and tested on Creality Ender 3. The experiments showed that the developed model can successfully predict the required compensation and can be applied during the printing process. The proposed algorithm helps to facilitate and automate the process of extrusion dynamics compensation which will expand the possibilities of FDM printers’ application in industrial conditions. The obtained algorithm can improve the accuracy and printing speed which will subsequently help to increase the economic independence and competitiveness of small design organizations and enterprises in Russia that use 3D printers. This research expands the possibilities of rapid prototyping and may help to ensure the rapid creation of pilot batches.

Towards Multilayered Coatings of 304L Stainless Steels Using Friction Surfacing

Abstract The objective of this work is to study friction surfacing process variability when depositing multilayered coatings. This is motivated by the need to maintain deposition quality when depositing multiple friction surfacing layers, whether for repair, remanufacturing, or new part creation using this solid-state metal additive manufacturing process. In this study, 10-mm-diameter 304L stainless steel rods were used to create up to five layers of 40-mm-long coatings on 304L substrates using a constant set of processing parameters. In-process measurement of forces (X, Y, Z), flash temperature, flash geometry, layer temperature, and post-process measurement of layer geometry, microhardness, and microstructure are used to characterize changes in the friction surfacing process as more layers are deposited. It was observed that with increasing layers: layer thickness and deposition efficiency decrease; offsetting of the deposition towards the retreating side, and temperature in the deposited layer increase; and flash temperature does not change. Metallurgical analyses of friction-surfaced cross-sections revealed fine grain refinement and transformation of base austenite to strain-induced martensite. It is concluded that the process parameters need to be adjusted even after the second or third layer is deposited, corrections to the tool path are required after a couple of layers, and the measured process forces, as well as deposited layer temperature, may be useful to monitor and control the process and its instabilities.

Quantifying Basal Roughness and Internal Layer Continuity Index of Ice Sheets by an Integrated Means with Radar Data and Deep Learning

Understanding englacial and subglacial structures is a fundamental method of inferring ice sheets’ historical evolution and surface mass balance. The internal layer continuity index and the basal roughness are key parameters and indicators for the speculation of the relationship between the ice sheet’s internal structure or bottom and ice flow. Several methods have been proposed in the past two decades to quantitatively calculate the continuity index of ice layer geometry and the roughness of the ice–bedrock interface based on radar echo signals. These methods are mainly based on the average of the absolute value of the vertical gradient of the echo signal amplitude and the standard deviation of the horizontal fluctuation of the bedrock interface. However, these methods are limited by the amount and quality of unprocessed radar datasets and have not been widely used, which also hinders further research, such as the analysis of the englacial reflectivity, the subglacial conditions, and the history of the ice sheets. In this paper, based on geophysical processing methods for radar image denoising and deep learning for ice layer and bedrock interface extraction, we propose a new method for calculating the layer continuity index and basal roughness. Using this method, we demonstrate the ice-penetrating radar data processing and compare the imaging and calculation of the radar profiles from Dome A to Zhongshan Station, East Antarctica. We removed the noise from the processed radar data, extracted ice layer continuity features, and used other techniques to verify the calculation. The potential application of this method in the future is illustrated by several examples. We believe that this method can become an effective approach for future Antarctic geophysical and glaciological research and for obtaining more information about the history and dynamics of ice sheets from their radar-extracted internal structure.

Biomechanical evaluation of femoral neck fracture osteosynthesis

Bone geometry, density, and thickness of the cortical layer of the femoral neck (FN) contribute to the mechanical strength in osteosythesis of femoral neck fractures (FNF) in young adults. The available techniques for fracture fixation of the FN are reviewed with respect to the biomechanical stability.A biomechanical study of the osteosynthesis stability of the FNF with three cannulated screws was carried out using synthetic models of the proximal part of the femoral bone (FB). The experimental models were divided into 4 groups. Each group related to the configuration of screws in the FN. The vertical and horizontal FNF stability was assessed using two series of load. In series I, models were loaded with forces in the longitudinal axis to the FB and in series II, forces acted in the perpendicular direction to the FB axis. The loading forces were evaluated when the displacement of 2 mm fragments was achieved. The highest stability strengths were obtained in group I in the both series ‒ 1898 N with a vertical load and 1046 N with a horizontal load. Further, in decreasing order, the results of stability were obtained in groups II, III and IV.In this study, it was found that the consideration of the position of screws according to architectonics of the FN is crucial for fragment stability. The triangular position of screws with three points of contact with the compact bone ensures the maximum stability of the construct in osteosynthesis of the FN fractures, which is comparable to the normal walking load conditions.We hypothesize that osteosynthesis of FN fractures with three screws in a triangular manner could provide a better stability when inserted into the dense tissues of the proximal FB with relation to bone architectonics. To ensure a maximum stability, each screw should have three points of contact with the compact bone – the lateral cortical wall of the subtrochanteric region of the FB, the inner wall of the FN, and the compact part of the FB head. New triangular configuration of screws’ placement could have a better neutralization of share forces in FN fractures.

Nano X-ray Tomography Application for Quantitative Surface Layer Geometry Analysis after Laser Beam Modification.

Analysis of the geometrical structure of the surface of materials is an issue already widely recognised and included in international standards. The authors present the possibilities of extending the analysis of the coatings’ geometrical structure through X-ray nanotomography imaging, three-dimensional image processing, and stereological methods. Analysis of the state of the art reveals that there are no scientific rapports (indexed by Scopus) on the application X-ray nanotomography for analysis of the geometry of a coating. The presented study shows that this imaging technique can be applied and provide additional information on the quality of the layer. The comparative tests were carried out on samples with a cermet coating before and after laser treatment, including standard tests of the surface geometry and the analysis of three-dimensional images obtained from nanotomography. A set of parameters describing the compactness and thickness distribution of the applied coating is proposed, which facilitates the qualitative assessment of the application process and improvements through the additional processing of technological layers. The obtained results show that although the average thickness values before and after laser treatment did not differ significantly, their distribution on the sample surface was different, as presented in the visualisation. The determined stereological parameter NV (number of objects per unit volume) allowed for the assessment of the layer compactness, and as the analyses showed, this value decreased by more than two times after laser treatment. The analysis of the degree of sample coverage by the cermet layer showed that it increased from 70% to 95% after laser treatment, which confirms the treatment’s positive effect on the layer’s quality. This research shows that three-dimensional analysis significantly enriches the information about the geometry of the surface layer, providing data which other research techniques are unable to acquire.

Nanofluidic Membranes to Address the Challenges of Salinity Gradient Energy Harvesting: Roles of Nanochannel Geometry and Bipolar Soft Layer.

Researchers are looking for new, clean, and accessible sources of energy due to rising global warming caused by the usage of fossil fuels and the irreversible harm that this does to the environment. Water salinity is one of the newest and most accessible renewable energy sources, which has sparked a lot of interest. Reverse electrodialysis (RED) has been utilized in the past to turn saline water into electricity. NRED, a reverse electrodialysis method utilizing nanofluidics, has gained popularity as nanoscale research advances. Developing and evaluating NRED systems is time-consuming and expensive due to the method's novelty; thus, modeling is required to identify the best locations for implementation and to comprehend its workings. In this work, we examined the influence of bipolar soft layer and nanochannel geometry on ion transfer and power production simultaneously. To achieve this, the two trumpet and cigarette geometries were coated with a bipolar soft layer so that both negative (type (I)) and positive (type (II)) charges could be positioned in the nanochannel's small aperture. After that, at steady state conditions, the Poisson-Nernst-Planck (PNP) and Navier-Stokes (NS) equations were solved concurrently. The findings revealed that altering the nanochannel coating from type (I) to type (II) alters the channel's selectivity from cations to anions. An approximately 22-fold improvement in energy conversion efficiency was achieved by raising the concentration ratio from 10 to 100 for the type (I) trumpet nanochannel. Type (I) cigarette geometry is advised for maximum power output at low and medium concentration ratios, whereas type (I) trumpet geometry is recommended for the maximum power production at high concentration ratios.

Galactic Winds and Bubbles from Nuclear Starburst Rings

Galactic outflows from local starburst galaxies typically exhibit a layered geometry, with cool 104 K flow sheathing a hotter 107 K, cylindrically collimated, X-ray-emitting plasma. Here we argue that winds driven by energy injection in a ring-like geometry can produce this distinctive large-scale multiphase morphology. The ring configuration is motivated by the observation that massive young star clusters are often distributed in a ring at the host galaxy’s inner Lindblad resonance, where larger-scale spiral arm structure terminates. We present parameterized three-dimensional radiative hydrodynamical simulations that follow the emergence and dynamics of energy-driven hot winds from starburst rings. In this letter, we show that the flow shocks on itself within the inner ring hole, maintaining high 107 K temperatures, while flows that emerge from the wind-driving ring unobstructed can undergo rapid bulk cooling down to 104 K, producing a fast hot biconical outflow enclosed by a sheath of cooler nearly comoving material without ram pressure acceleration. The hot flow is collimated along the ring axis, even in the absence of pressure confinement from a galactic disk or magnetic fields. In the early stages of expansion, the emerging wind forms a bubble-like shape reminiscent of the Milky Way’s eROSITA and Fermi bubbles and can reach velocities usually associated with active-galactic-nucleus-driven winds. We discuss the physics of the ring configuration, the conditions for radiative bulk cooling, and the implications for future X-ray observations.

Concentration mixing and melt pool solidification behavior during the magnetic field assisted laser cladding of Fe-Cr-based alloy on 45 steel surface

Magnetic field-assisted laser cladding is an effective method in suppressing defects and improving the physical properties of the cladding layer, widely used in mold repair, aerospace, and additive manufacturing fields alike. However, magnetic field-assisted laser cladding cannot predict the effect of magnetic fields on composition mixing and melt pool solidification behavior. To solve this problem, a 3D magnetic field-assisted laser cladding numerical model including the chemical substance transfer, magnetic field, fluid flow, fluid heat transfer and dynamic grid was established in this paper. Based on the proposed model, the cladding layer geometry and concentration distributions of both the iron (Fe) and chromium (Cr) were predicted. The influences of magnetic field on the melt pool solidification behavior and the concentration mixing process were further developed. The results have shown that the maximum chromium concentration on the cladding layer marking line decreases from 10.9 wt% to 9.8 wt% within 0–0.5 T, and gradually increases to 13 wt% within 0.5–1.2 T. During the melt pool solidification, the maximum cooling rate (Gs*Rs) increases with the magnetic field strength – from 5.58 × 103 K/s to 7.1 × 103 K/s, while the morphological parameter (Gs/Rs) simultaneously decreases from 2.88 × 109 s∙K/m2 to 7.97 × 108 s∙K/m2. Such behavior implies that the crystal size decreases as the magnetic field strength increases. Additionally, the composition distribution at the beginning and bottom of the cladding layer is uneven. The crystal size decreases gradually when moving from the bottom to the top of the melt layer. Simultaneously, the crystal structure changed from slatted crystals at the bottom to columnar, cellular, and equiaxed crystals at the top. As such, the study provides an effective way to predict elemental concentrations and solidification behavior during magnetic field-assisted laser cladding.

Penetration Behavior of the Footing of Jack-Up Vessel of OWTs in Thin Stiff over NC Clay

This study investigated the behavior of the spudcan foundation of jack-up vessels of offshore wind turbines during the undrained vertical penetration into thin stiff-over-normally consolidated clay. Large deformation finite element (LDFE) analyses were used to simulate the continuous spudcan penetration into the seabed surface. Detailed parametric analysis was performed to explore a range of normalized soil properties and layer geometry and roughness of the soil–spudcan interface. The results were validated against previously reported data. The LDFE results were consistent with those of centrifuge tests. The evolving soil-failure patterns revealed soil backflow and the trapping of stronger top-layer material beneath the spudcan. The plug shape was influenced by the top layer thickness, the strength gradient of the bottom layer, and the relative strength ratio, which also affected the penetration resistance of soils. In this study, an expression was derived to quantify the plug shape with the aim of providing a theoretical basis for the design of spudcan footings with penetration resistance suitable for thin stiff-over-soft clay.

Distinct superconducting behaviors of pressurized WB2 and ReB2 with different local B layers

The recent discovery of superconductivity up to 32 K in the pressurized MoB2 reignites the interests in exploring high-Tc superconductors in transition-metal diborides. Inspired by that work, we turn our attention to the 5d transition-metal diborides. Here we systematically investigate the responses of both structural and physical properties of WB2 and ReB2 to external pressure, which possess different types of boron layers. Similar to MoB2, the pressure-induced superconductivity was also observed in WB2 above 60 GPa with a maximum Tc of 15 K at 100 GPa, while no superconductivity was detected in ReB2 in this pressure range. Interestingly, the structures at ambient pressure for both WB2 and ReB2 persist to high pressure without structural phase transitions. Theoretical calculations suggest that the ratio of flat boron layers in this class of transition-metal diborides may be crucial for the appearance of high Tc. The combined theoretical and experimental results highlight the effect of geometry of boron layers on superconductivity and shed light on the exploration of novel high-Tc superconductors in borides.

Effect of the IMC layer geometry on a solder joint thermomechanical behavior

PurposeIn a printed circuit board assembly (PCBA), the coefficient of thermal expansion (CTE) mismatch between the solder joint materials has a detrimental impact on reliability. The mechanical stresses caused by the thermal changes of the assembly lead to fatigue and sometimes the failure of the solder joints. The purpose of this study is to propose a novel pad design to obtain an interrupted solder/substrate interface, to improve the PCBA reliability.Design/methodology/approachAn interruption in the continuous intermetallic compound (IMC) layer of a solder joint was implemented, by the deposition of a silicone film in the pad, changing its geometry. That change allows a redistribution of stresses in the most ductile zone of the solder joint, the solder. The stress concentration at the solder/substrate interface is reduced, as well as the general state of stress at the solder joint.FindingsA new way was developed to reduce the stress on the solder joints, caused by thermal variations, because of the different components CTEs mismatch. This new method consists of interrupting the IMC layers of the solder joint, strategically, redirecting the usual stresses to a more ductile area of the joint, the solder. This is an innovative method that allows increase the lifetime of PCBAs and the equipments.Originality/valueIn this study, a new pad design concept for higher solder joint reliability was developed to reduce the shear stress in the solder joints because of the CTE mismatch between all the solder joint components.

Modeling the acoustic behavior of stepwise gradient porous structures

Spatial property gradients can significantly enhance the noise reduction potential of porous structures. However, predicting the acoustic behavior of structures with gradient microstructures continues to remain a challenge. For porous structures with controlled periodic microstructures, researchers have recently demonstrated the use of a multiscale asymptotic method to extract the acoustic transport properties necessary for use in semi-empirical predictive models. Here, we propose the adaptation of this method to enable the modeling of porous absorbers with stepwise property gradients. The unit cell of the chosen microstructure is modeled in COMSOL Multiphysics and the acoustic transport properties are extracted using the multiscale method. The extracted properties are then used to formulate the transfer matrix of each unit cell. The global sound absorption and transmission loss behavior of the stepwise gradient structures are further predicted by combining the appropriate local transfer matrices. Our results show that the integration of the unit cell and transfer matrix methods provides a robust way of predicting the acoustic behavior of stepwise gradient porous structures with various combinations of layer thicknesses and geometries. The method provides a computationally efficient method to model such structures and can further the development of porous structures with application-specific acoustical properties.

Morphology and Optical Properties of Nanostructure Porous Silicon Prepared by Electrochemical Etching for Solar Cells Application

In this work, nanostructure porous silicon surface was prepared using electrochemical etching under different current densities. I have studied the surface morphology and photoluminsense of four samples prepared at current densities 5 , 10 , 15 and 20 mA/cm2at fixed etching time 10 min.photoluminsense study showed that the energy gap of the porous silicon samples are is 3.1eV,and it was higher than the energy gap of bulk silicon which was 1.08 eV. A scanning electron microscope (SEM) micrographs were used to estimate the surface area. The surface area of the porous layer is strongly dependent on the porous layer geometry and its depth. The optical reflectance measurements were obtained by using an optical reflectometer (UV) which is equipped with an integrating sphere in the (200-1100) nm wavelength range, which reveals that the textured cells with PS layer sources have lower reflectivity value compared to the textured cell without PS structure.

Height control in GMA-AM using external wire as controlling variable

ABSTRACT Gas metal arc additive manufacturing (GMA-AM) is gaining great attention to produce large-scale parts owing to its merits of low device investments and high deposition rates. Despite this fact, a robust control system for deposition height in thin-walled parts is yet to be developed due to the lack of an appropriate controlling variable. This study attempts to propose an external wire-based GMA-AM technique to solve this issue. The influences of arc current, travel speed, and external wire feed speed (EWFS) on layer geometry were studied. It is indicated that the EWFS exhibits a greater influence on the layer height of thin walls than the arc current and the travel speed. The nozzle to the top surface distance (NTSD), monitored via a vision sensor, was extracted by Median filter, Sobel algorithm, Canny algorithm, and Hough transform. The dynamics between the NTSD and the EWFS were established via a nonlinear model. A parameter self-tuning fuzzy controller was designed to control the NTSD via changing the EWFS. System simulation tests and control tests were performed to validate the robustness of the parameter self-tuning fuzzy controller.

Crystalline phase transitions and water-soluble complexes of copper(I) 2-hydroxyethanethiolate

The coordination polymer copper(I) 2-hydroxyethanethiolate, (CuSCH2CH2OH)n, though insoluble in all common solvents, dissolved readily in basic aqueous solutions of the thiolate anion (HOCH2CH2S–) of 2-mercaptoethanol to form a single species: the tetranuclear cluster [Cu4(µ-SCH2CH2OH)6]2–. From this solution were grown X-ray quality single crystals of copper(I) 2-hydroxyethanethiolate. This compound underwent a hitherto unknown crystal phase transition at ca. 6 °C, from point group P212121 to Pna21, with noticeable changes in the geometry of the Cu-S layer and in the orientation of the alkylthiolate side chains. When the bulky base tetrabutylammonium hydroxide was employed in the aqueous thiolate solution used to dissolve (CuSCH2CH2OH)n, the water-soluble polynuclear copper(I) complex bis(tetrabutylammonium) hexakis(µ-2-hydroxyethanethiolato) tetracuprate(I), [(C4H9)4N]2[Cu4(µ-SCH2CH2OH)6], could be isolated as X-ray quality crystals. Structural characterization of this complex revealed a tetrahedral arrangement of copper(I) centers with thiolates bridging the edges of the tetrahedra. On standing, this complex degraded to a larger polynuclear Cu(I) sulfide cluster.

Assessing the Accuracy of a Borehole-Controlled P-Wave Velocity Model of Yucca Flat, Nevada Using Large-N Seismic Data

ABSTRACT With geologic data from over 950 boreholes, Yucca Flat basin, residing on the Nevada National Security Site, has excellent borehole control on stratigraphy. These data were used to create a Geologic Framework Model (GFM) of the basin. Of these boreholes, 188 have corresponding downhole seismic survey data, which were used to determine average P-wave velocities of the geologic units and create a GFM seismostratigraphic model (GFM-SS). With the acquisition of six new active-source large-N datasets in Yucca Flat, we can now quantitatively assess the accuracy of the GFM-SS previously controlled only by borehole data. For each of the six datasets, we subset the GFM to the region of interest and create a forward model of P-wave travel times for the GFM-SS given the large-N source-receiver geometries. We first made trial-and-error adjustments to the unit velocities (while keeping the layer geometry intact) to improve the travel-time residuals. We then implemented a simulated annealing approach to find the optimal velocity model for each dataset. Our results indicate that the borehole-controlled model overestimates alluvium velocities across Yucca Flat. This result persists even when we make smaller GFM-SS models that are local to individual large-N experiments. We hypothesize that this result is a combination of shorter ray paths and the resulting lack of interaction with large-scale features (such as faults), as well as less attenuation of high frequencies in the borehole data. Both the current GFM-SS and the updated model based on median velocities that we present here overgeneralize local unit velocities, which can be quite heterogeneous in Yucca Flat.

Proposing a sequential iterative method based on a per-unit model for rotor shape optimization in permanent magnet assisted synchronous reluctance motors

PurposeDuring the design process of synchronous reluctance motors (SynRMs), one crucial step, after its main dimensioning, is optimizing the rotor geometry for maximum average torque and minimum torque ripple. However, because of the complexity of rotor flux-barrier layers geometry, the number of rotor geometrical parameters is high and this step could be quite complex and time-consuming. To obtain a good performance, one needs a robust algorithm to optimize the rotor geometry. The purpose of this paper is to present a sequential iterative method for rotor shape optimization in SynRMs based on the per-unit rotor model to maximize the average torque and minimize the torque ripple.Design/methodology/approachIn the presented method, at first, rotor geometrical parameters are classified into several groups based on their geometrical similarities, and then optimization is done on these individual groups iteratively. The method starts with an arbitrary feasible rotor geometry and proceeds to optimize it. Because the method’s performance depends on initial rotor geometry, different cases are studied to investigate the convergence and robustness of the method. The MATLAB software is used to implement the optimization algorithm, and the ANSYS Maxwell software is used for the finite element analysis.FindingsThe performance of the proposed method is studied on a three-phase 0.75 kW-1,500 rpm permanent magnet assisted SynRM. The results show that the method improves the average torque while reducing the torque ripple. Even if the method starts with an inappropriate initial rotor geometry, it is robust enough and converges within an acceptable number of iterations.Originality/valueThe value of this paper is in introducing a per-unit rotor model. When the authors optimize the rotor geometry for a specific motor rating, it can be scaled up or down for other ratings with little effort. In this work, the number of rotor poles is four and the number of rotor flux-barrier layers per pole is three. Other combinations could be analyzed in future studies.

Surgical scene generation and adversarial networks for physics-based iOCT synthesis.

The development and integration of intraoperative optical coherence tomography (iOCT) into modern operating rooms has motivated novel procedures directed at improving the outcome of ophthalmic surgeries. Although computer-assisted algorithms could further advance such interventions, the limited availability and accessibility of iOCT systems constrains the generation of dedicated data sets. This paper introduces a novel framework combining a virtual setup and deep learning algorithms to generate synthetic iOCT data in a simulated environment. The virtual setup reproduces the geometry of retinal layers extracted from real data and allows the integration of virtual microsurgical instrument models. Our scene rendering approach extracts information from the environment and considers iOCT typical imaging artifacts to generate cross-sectional label maps, which in turn are used to synthesize iOCT B-scans via a generative adversarial network. In our experiments we investigate the similarity between real and synthetic images, show the relevance of using the generated data for image-guided interventions and demonstrate the potential of 3D iOCT data synthesis.