Outer Shape Research Articles

Text2shape: Intelligent computational design of car outer contour shapes based on improved conditional Wasserstein generative adversarial network

To provide technical support for the initial design of products, we propose an innovative text2shape-based technology for intelligent computational design, which can map engineering semantics to functional/structural/Kansei feature spaces to generate product shapes. New energy vehicles were selected as the application object of this technology, as there are many creative ideas for the outer contour design of new energy vehicles. Firstly, a dataset with 2900 + samples was built based on feature engineering (FE) and Kansei engineering (KE). Each sample contains the car’s outer contour shape’s functional, structural, and Kansei features. Secondly, we proposed an improved conditional Wasserstein generative adversarial network (CWGAN) model suitable to the dataset. The generator’s loss in the model is designed to evaluate the authenticity of the generated results, while the discriminator’s loss assesses the conditional matching of these results. Finally, in case studies, the trained CWGAN was compared with the conditional variational auto-encoder (C-VAE), diffusion, Wasserstein generative adversarial network with gradient penalty (WGAN-GP) and style generative adversarial network (StyleGAN) models, demonstrating superior performance.

Classification of Kinalabasa Tomato Using Convolutional Neural Network

Determining the freshness of tomatoes is essential for evaluating their quality, impacting both consumer satisfaction and the economic benefits for farmers. Freshness is typically assessed by outer appearance, including color, size, and shape, with skin color indicating ripeness and influencing selling price. Properly assessing freshness also helps determine the shelf life of stored tomatoes. This study introduced an affordable and straightforward technique for classifying agricultural commodities using image processing, focusing on Kinalabasa tomatoes and classifying them based on color features into three categories. The study employed the MobileNetv2 architecture for training and testing the dataset, aiming to improve the classification of Kinalabasa tomatoes through deep learning techniques. The study evaluated the model's performance using metrics like accuracy, precision, sensitivity, and specificity. The optimal configuration for classifying Kinalabasa tomatoes was determined to be 10 epochs and a learning rate of 0.001. MobileNetv2 achieved a high accuracy rate of 94%, demonstrating its effectiveness in classifying tomatoes, though the specificity rate of 64% indicated some room for improvement in identifying negative instances. Comparing MobileNetv2 with ShuffleNet architectures will provide further insights into their respective effectiveness and performance in this classification task.

Overview of results from the 2023 DIII-D negative triangularity campaign

Abstract Negative triangularity (NT) is a potentially transformative configuration for tokamak-based fusion energy with its high-performance core, edge localized mode (ELM)-free edge, and low-field-side divertors that could readily scale to an integrated reactor solution. Previous NT work on the TCV and DIII-D tokamaks motivated the installation of graphite-tile armor on the low-field-side lower outer wall of DIII-D. A dedicated multiple-week experimental campaign was conducted to qualify the NT scenario for future reactors. During the DIII-D NT campaign, high confinement ( H 98 y , 2 ≳ 1), high current ( q 95 < 3), and high normalized pressure plasmas ( β N > 2.5) were simultaneously attained in strongly NT-shaped discharges with average triangularity δ avg = −0.5 that were stably controlled. Experiments covered a wide range of DIII-D operational space (plasma current, toroidal field, electron density and pressure) and did not trigger an ELM in a single discharge as long as sufficiently strong NT was maintained; in contrast, to other high-performance ELM-suppression scenarios that have narrower operating windows. These strong NT plasmas had a lower outer divertor X-point shape and maintained a non-ELMing edge with an electron temperature pedestal, exceeding that of typical L-mode plasmas. Also, the following was achieved during the campaign: high normalized density ( n e / n GW of at least 1.7), particle confinement comparable to energy confinement with Z eff ∼ 2 , a detached divertor without impurity seeding, and a mantle radiation scenario using extrinsic impurities. These results are promising for a NT fusion pilot plant but further questions on confinement extrapolation and core-edge integration remain, which motivate future NT studies on DIII-D and beyond.

Machine learning with analysis-of-variance-based method for identifying rice varieties

Rice, which has the highest production and consumption rates worldwide, is one of the main nutrients in our country because it is economical and nutritious. Rice undergoes various stages of production from the field to the dinner tables, with the cleaning phase involving separation of rice from unwanted materials. There are different varieties of rice such as arborio, basmati, aracadaga, ipsala, and jasmine. Therefore, it is necessary to identify rice varieties based on customer demands. Rice variety identification is primarily based on its outer appearance, including color, size, and shape. In this study, 75,000 rice grain images, including 15,000 images for each variety, were considered. Using a combination of 12 morphological features, four shape features, and 90 color features obtained from five different color spaces, 106 features were extracted from the images. An analysis of variance (ANOVA) was employed to select high-rank features, which were then fed to a support vector machine (SVM) for classification. The experimental results demonstrated that the utilization of 40 high-rank features yielded impressive outcomes, with a validation accuracy of 99.89 %, cost value of 16, test accuracy of 99.81 %, and cost value of 28. These high accuracy rates are particularly noteworthy, as they indicate the robustness and reliability of the proposed methodology in distinguishing between different rice varieties with minimal error. This high level of precision is critical for practical applications, such as quality control in rice production, to ensure that customers receive the specific rice variety they demand. Implementing this methodology in real-world scenarios could significantly enhance the efficiency and accuracy of the rice variety identification processes, benefiting both producers and consumers.

Self-growing bionic leaf-vein fins for high-power-density and high-efficiency latent heat thermal energy storage

Latent heat storage (LHS) has found extensive applications across various fields. However, large-scale deployment is still restricted due to the worse thermal charging performance of traditional LHS systems. In this research, the self-growing fins of the tube-shell LHS system are designed via the bionic topology optimized method to improve thermal storage performances, inspired by the structures and functions of leaf veins. Notably, the system installed with topology-optimized self-growing fins (T-FIN) demonstrates the shortest melting time, largest specific power density (SPD), and highest efficiency simultaneously. At the inlet conditions of 0.5 L min−1 and 358.15 K, the thermal charging time decreases by 46.4 % and 57.1 % compared with the systems equipped with traditional long-fins (L-FIN) and short-fins (S-FIN), while increasing the SPD by 80.6 % and 125.7 %, respectively. Moreover, the efficiency of exergy and entransy storage is 2.49 and 2.42 times, respectively, as large as those of the S-FIN. The intrinsic mechanism is attributed to enhanced synergy between the liquid-PCM temperature field and the flow field. Furthermore, outer tube shapes are optimized by the Genetic Algorithm for the first time, leading to a further decrease in charging time by 21.57 % compared with its original counterpart. These findings provide a valuable idea for designing efficient bionic LHS systems.

Development of nonlinear flat shell element with nonlinear thickness variation for highly flexible wind turbine blade

Large deformation from continuously varied thicknesses on existing and wind turbine blade shell structures is investigated. Various structure models having complicated outer shapes and thickness variations are considered and validated in this paper. A co-rotational method is developed to analyze geometric nonlinearity with a triangular shell structure. The updated stiffness matrix from interpolated thickness function and integral formulation is suggested to consider complicated geometry and thickness variation. Moreover, the co-rotational flat shell element based on the updated stiffness matrix is developed to analyze various nonlinear shell structures, which are the main feature of this research. The numerical analysis for structure deformations show well matched trends in static load analysis. Furthermore, the deformation of a simplified flexible wind turbine blade having tapered geometry and various thickness cases is adopted as a practical case. Moreover, modal analysis for composite beam structure is performed to verify the dynamic problems. The structural behaviors of the nonlinear thickness shell are validated against the solid and the shell models in commercial software, ABAQUS.

Spin-It Faster: Quadrics Solve All Topology Optimization Problems That Depend Only On Mass Moments

The behavior of a rigid body primarily depends on its mass moments, which consist of the mass, center of mass, and moments of inertia. It is possible to manipulate these quantities without altering the geometric appearance of an object by introducing cavities in its interior. Algorithms that find cavities of suitable shapes and sizes have enabled the computational design of spinning tops, yo-yos, wheels, buoys, and statically balanced objects. Previous work is based, for example, on topology optimization on voxel grids, which introduces a large number of optimization variables and box constraints, or offset surface computation, which cannot guarantee that solutions to a feasible problem will always be found. In this work, we provide a mathematical analysis of constrained topology optimization problems that depend only on mass moments. This class of problems covers, among others, all applications mentioned above. Our main result is to show that no matter the outer shape of the rigid body to be optimized or the optimization objective and constraints considered, the optimal solution always features a quadric-shaped interface between material and cavities. This proves that optimal interfaces are always ellipsoids, hyperboloids, paraboloids, or one of a few degenerate cases, such as planes. This insight lets us replace a difficult topology optimization problem with a provably equivalent non-linear equation system in a small number (<10) of variables, which represent the coefficients of the quadric. This system can be solved in a few seconds for most examples, provides insights into the geometric structure of many specific applications, and lets us describe their solution properties. Finally, our method integrates seamlessly into modern fabrication workflows because our solutions are analytical surfaces that are native to the CAD domain.

Research progress of three-dimensional bioprinting technology in auricle repair and reconstruction

To review the research progress on the application of three-dimensional (3D) bioprinting technology in auricle repair and reconstruction. The recent domestic and international research literature on 3D printing and auricle repair and reconstruction was extensively reviewed, and the concept of 3D bioprinting technology and research progress in auricle repair and reconstruction were summarized. The auricle possesses intricate anatomical structure and functionality, necessitating precise tissue reconstruction and morphological replication. Hence, 3D printing technology holds immense potential in auricle reconstruction. In contrast to conventional 3D printing technology, 3D bioprinting technology not only enables the simulation of auricular outer shape but also facilitates the precise distribution of cells within the scaffold during fabrication by incorporating cells into bioink. This approach mimics the composition and structure of natural tissues, thereby favoring the construction of biologically active auricular tissues and enhancing tissue repair outcomes. 3D bioprinting technology enables the reconstruction of auricular tissues, avoiding potential complications associated with traditional autologous cartilage grafting. The primary challenge in current research lies in identifying bioinks that meet both the mechanical requirements of complex tissues and biological criteria.

Towards an objective assessment of tree vitality: a case study based on 3D laser scanning

Key messageAnalyzing fine branch length characteristics in beech trees using single-tree QSMs derived from laser scanning reveals insights into drought-induced changes in vitality, which include branch shedding and reduced shoot growth.Climate change causes increasing temperatures and precipitation anomalies, which result in deteriorations of tree health and declines in ecosystem services of forests. It is therefore crucial to monitor tree vitality to preserve forests and their functions. However, methods describing tree vitality in situ are lacking reproducibility or are too laborious. Thus, we tested a laser-scanning based approach, assuming that an objective measurement of a tree’s outer shape should reveal changes according to tree vitality. QSMs of similarly sized beech trees from stands with varying degrees of drought damage were used. Absolute and relative fine branch lengths, their ratio to lower order branches’ lengths and their progressions over relative height were targeted to identify fine branch dieback and reduced growth. The absolute fine branch length was significantly lower for less vital beech trees, especially within the upper crown, leading to a less top-heavy vertical distribution of fine branches and a reduced fine-to-base order branch length ratio. Hence, height-dependent characteristics of fine branch lengths differed between vitalities. We conclude that using fine branch length characteristics derived from QSMs can be helpful in vitality assessments of beech trees. Still, uncertainties with regard to the plotwise assessment and problems with QSM quality are present.

Centimeter-scale sedimentary structures in a lacustrine delta front, northern China: Ripples or Froude supercritical-flow bedforms?

Sedimentary strata are a significant record of the Earth and planetary history, and accurate recognition of sedimentary structures and their link to environmental conditions is a key component in deciphering past surface processes. Centimeter-scale sedimentary structures are commonly acknowledged as ripple cross-laminations, but here we document ambiguous centimeter-scale structures from a lacustrine delta front in northern China, that at careful look do not seem to fit with the known ripple cross-lamination criteria. The here documented sedimentary structures range from scour-and-fill, irregular lenses with structureless or low- and high-angle, up- and downstream dipping, concave and convex laminations. These centimeter-scale sedimentary structures thus considerably differ from ripple cross-laminations in their outer shape, internal organization, and morphometric parameters. Detailed comparison of these centimeter-scale structures with Froude supercritical-flow structures suggests that they were likely produced by Froude supercritical flows. Such centimeter-scale supercritical structures are not unique in the Bantanzi delta, as they have been also documented in a variety of settings ranging from rivers to deepwater turbidites. In light of this finding, we expand the Froude supercritical-flow sedimentary structures to centimeter scale, and advocate caution in interpreting centimeter-scale sedimentary structures axiomatically as ripple laminations.

Seed morphology in the genus Matthiola R. Br. (Brassicaceae): Identification of species and systematic implications

AbstractSeed coat morphology of 34 species of Matthiola R.Br. has been studied using light and scanning electron microscopy to assess their investigative value for systematic studies. Macro‐ and micromorphological characters, including seed shape, color, size, wing, and radicle position relative to cotyledons, epidermal cell shape, anticlinal boundaries, and periclinal cell wall are presented. Seed shape, color, and radicle position relative to cotyledons have limited taxonomic significance, as their variation is unhelpful. There against, seed size, wing, and seed coat ornamentation present informative characteristics that can be used professionally in distinguishing the studied taxa. Six different types of seed anticlinal cell wall boundaries are recognized and five different outer periclinal cell wall shapes are described. The sculpture of the secondary cell wall varies from striate, micropapillate to microreticulate, and smooth to fine folds. The taxonomic and phylogenetic implications of seed coat micromorphology were compared with those of the existing gross morphological and molecular data. Seed character analysis offered useful data for evaluating the taxonomy of Matthiola both on subgeneric and sectional levels. Seed micromorphological characters provide evidence that M. odoratissima and M. ovatifolia should be preserved as separate species. In addition, M. ghorana is not conspecific with M. graminea. Furthermore, M. tricuspidata was unique in the seed characters. A key to the identification of the examined taxa based on seed characters is provided.

Aerodynamic design optimization of locally built FSR Isuzu bus through numerical simulation

Reducing the fuel consumption of commercial vehicles—especially those used for public transportation—has become increasingly important due to advancements in the automotive industry. On the other hand, the main disadvantages of buses and other commercial vehicles are their fuel consumption, exhaust pollutants, and crosswind stability. Most buses built in Ethiopia have aerodynamic rectangular shapes and strong drag resistance forces, which lead to higher fuel consumption. One of the most accessible buses in Ethiopia is the FSR Isuzu Bus; its external body is locally constructed and has a poor aerodynamic shape. The primary goal of this study is to reduce aerodynamic drag force by improving the outer body shape of the current FSR Isuzu Bus. It also aims to examine the impact of roughness (strip) on the overall aerodynamic characteristics of the bus when it encounters crosswinds, thereby reducing fuel consumption, roll moment, and side force. For computational fluid dynamics (CFD) analysis, ANSYS Fluent is used, and Solidwork is used to model the bus body. A comparison is made between the current CFD analysis of the bus body and the modified design at varying speeds. Three separate models are used in the analysis. At an average speed of 100 kmph, 29.58% (4 to 5 liters) of fuel can be saved, and the drag force is reduced by roughly 49.7% when comparing the new concept to the current bus. By utilizing a strip on the bus’s roof, the side force coefficient and the roll moment coefficient are subsequently reduced from model two to model three by 8.76% and 9.01%, respectively. The study’s conclusions indicate that the external body shape changes have reduced drag; and, adding roof strips has decreased drag to acceptable level and enhanced crosswind stability.

Processing temperature-dependent nucleation and growth behaviors of polypropylene nucleated by a bisamide nucleating agent

It has been widely reported that the processing temperature significantly influenced the effectiveness of a β-nucleating agent (β-NA) in polypropylene (PP) and thus leads to variations in the final relative content of β-phase (kβ). To comprehensively understand the changing kβ with processing temperature, PP nucleated by a bisamide β-NA, N,N′-dicyclohexylterephthalamide (DCHT), was heating-treated at different temperatures (Tf) in the range of 200–250 °C, and the impact of Tf on the nucleation and subsequent growth behaviors of the α- and β-phases were separately investigated. Under low Tf, DCHT induced a high relative density of β-nuclei to α-nuclei (Nβ/Nα) with high total nucleation density (N), and both the α- and β-phases grew competitively until the crystallization ended. Under middle Tf, the Nβ/Nα became low with middle N induced by DCHT, and the faster-growing phase dominated the subsequent growth process. Under high Tf, there was a middle Nβ/Nα with low N, and the faster-growing phase became more dominant during the growth process. Based on the observed morphology of DCHT, the decreasing N with Tf could be associated with the specific surface area, the varying Nβ/Nα could be attributed to the variations in both the energy barrier and the surface area of β-nucleation under diverse DCHT morphologies, and the varying growth behavior was probably associated with the outer surface shape of diverse DCHT morphologies. Combining the thorough analysis of the changing nucleation and growth behaviors with Tf, a possible mechanism was proposed to explain the effect of processing temperature on the final polymorphic composition.

How can research on modern and fossil bones help us build more resistant columns?

Bone is an economical material. Indeed, as moving a heavy skeleton is energetically costly, the vertebrate skeleton is adapted to maximise resistance to the stresses imposed with a minimum amount of material, so that bone tissue is deposited where it is needed. Using bone as a source of inspiration should therefore reduce the manufacturing cost (both financial and ecological) and increase the strength (and lifespan) of bioinspired (BI) structures. This study proposes to investigate which adaptive features of the outer shape and inner structure of bone, related to compressive strength, could be used to build BI support structures. To do so, we explain the choice of the bones to be analysed and present the results of the biomechanical analyses (finite element analysis) carried out on virtual models built from the structures of the different bone models and of the mechanical tests carried out on 3D-printed versions of these models. The compressive strength of these direct bone BI columns was compared with each other, and with those of a conventional filled cylindrical column, and of a cylindrical column whose internal structure is BI from the radius of the white rhinoceros. The results of our comparative analyses highlight that the shape of long bones is less effective than a cylinder in resisting compression but underline the relevance in designing BI cylindrical columns with heterogeneous structures inspired by the radius of the white rhinoceros and the tibia of the Asian elephant, and raise the interest in studying the fossil record using the radius of the giant rhinocerotoid Paraceratherium.

How to make a bridal bouquet: sensory knowing in action

This study explored the planning and making of a bridal bouquet in classroom interaction between a teacher and a student in a Swedish upper-secondary adult floristry education school. The purpose was to empirically reveal floristry disciplinary aesthetics. Aesthetics can be said to involve the exploration of sensory perception in general, entailing a focus on tacit sensory knowing. Methodologically, this study drew on the principles of ethnomethodology and (multimodal) conversation analysis to investigate video-recorded empirical data. The analysis included three separate sequences of interaction after the student requested the teacher’s attention. In the sequences, the student repeatedly provided answers to her own known-answer questions, and it remained her privilege to define what should be done and why as a consequence of the teacher’s authoritative guiding and gentle support. The results include examples of floristry disciplinary aesthetics in action when making a bridal bouquet, such as airiness and the role of outer shape. Moreover, in situ aesthetic judgement as part of sensory knowing is shown to be ample in the form of embodied actions, such as showing with the hands and communicating with facial expressions.

Understanding the ant’s unique biting system can improve surgical needle holders

Mechanical grasping and holding devices depend upon a firm and controlled grip. The possibility to improve this gripping performance is severely limited by the need for miniaturization in many applications, such as robotics, microassembly, or surgery. In this paper, we show how this gripping can be improved in one application (the endoscopic needle holder) by understanding and imitating the design principles that evolution has selected to make the mandibles of an ant a powerful natural gripping device. State-of-the-art kinematic, morphological, and engineering approaches show that the ant, in contrast to other insects, has considerable movement within the articulation and the jaw´s rotational axis. We derived three major evolutionary design principles from the ant's biting apparatus: 1) a mobile joint axis, 2) a tilted orientation of the mandibular axis, and 3) force transmission of the adductor muscle to the tip of the mandible. Application of these three principles to a commercially available endoscopic needle holder resulted in calculated force amplification up to 296% and an experimentally measured one up to 433%. This reduced the amount of translations and rotations of the needle, compared to the needle's original design, while retaining its size or outer shape. This study serves as just one example showing how bioengineers might find elegant solutions to their design problems by closely observing the natural world.

Laser-based fabrication chain enabling high quality mini aspheres

In recent years, 3D machining in glass for micro-components has seen a notable boost, notably with the development of a novel optical fabrication chain. This approach uses lasers for shaping and polishing, enabling the creation of complex mini-optics efficiently. The process begins with selective laser-induced etching (SLE) to define the optics’ outer shape and surface figure. Subsequent polishing, using a “one-shot laser polishing” technique, removes imperfections and reduces roughness in a single step, achieving optical-grade smoothness. This fabrication chain is applicable to mini-aspheres as well, enhancing their production efficiency. Additionally, it allows for wafer-level production, where multiple mini-optics are interconnected on a single glass substrate.

Ultrasculptura of carpopodium surface in species of the Astereae tribe (Asteraceae)

The study discusses the ultrastructural characteristics of the carpopodium surface of cypselas in 81 species from 34 genera within 16 subtribes of the Astereae tribe (Asteraceae) observed using a scanning electron microscope. These species exhibit well-developed carpopodia categorized into three types: poorly advanced, moderately advanced, and highly advanced. The carpopodia in the species analyzed vary in type (symmetrical, asymmetric, interrupted), the number of cell rows, cell shape, cell orientation, and outer periclinal wall shape. Most species have symmetrical carpopodia with cells forming a complete ring consisting of different numbers of rows (ranging from 1 to 22), although asymmetric or interrupted carpopodia are also present but less common. Different types of carpopodia may exist within a subtribe or genus, and the structural characteristics of the carpopodium serve as a taxonomic criterion at the species level.

A Hydraulic Haptic Actuator for Simulation of Cardiac Catheters.

This article presents a haptic actuator made of silicone rubber to provide both passive and active haptic forces for catheter simulations. The haptic actuator has a torus outer shape with an ellipse-shaped inside chamber which is actuated by hydraulic pressure. Expansion of the chamber by providing positive pressure can squeeze the inside passage to resist the catheter traveling through. Further expansion can hold and push back the catheter in the axial direction to render active haptic forces. The size of the catheter passage is increased by providing negative pressure to the chamber, allowing various diameters of the actual medical catheters to be used and exchanged during the simulation. The diameter of the catheter passage can be enlarged up to 1.6 times to allow 5 to 7 Fr (1 Fr = 1/3 mm) medical catheters to pass through. Experiment results show that the proposed haptic actuator can render 0 to 2.0 N passive feedback force, and a maximum of 2.0 N active feedback force, sufficient for the cardiac catheter simulation. The haptic actuator can render the commanded force profile with 0.10 N RMS (root-mean-squares) and 10.51% L2-norm relative errors.

Explicit Topology Optimization of Voronoi Foams.

Topology optimization can maximally leverage the high DOFs and mechanical potentiality of porous foams but faces challenges in adapting to free-form outer shapes, maintaining full connectivity between adjacent foam cells, and achieving high simulation accuracy. Utilizing the concept of Voronoi tessellation may help overcome the challenges owing to its distinguished properties on highly flexible topology, natural edge connectivity, and easy shape conforming. However, a variational optimization of the so-called Voronoi foams has not yet been fully explored. In addressing the issue, a concept of explicit topology optimization of open-cell Voronoi foams is proposed that can efficiently and reliably guide the foam's topology and geometry variations under critical physical and geometric requirements. Taking the site (or seed) positions and beam radii as the DOFs, we explore the differentiability of the open-cell Voronoi foams w.r.t. its seed locations, and propose a highly efficient local finite difference method to estimate the derivatives. During the gradient-based optimization, the foam topology can change freely, and some seeds may even be pushed out of shape, which greatly alleviates the challenges of prescribing a fixed underlying grid. The foam's mechanical property is also computed with a much-improved efficiency by an order of magnitude, in comparison with benchmark FEM, via a new material-aware numerical coarsening method on its highly heterogeneous density field counterpart. We show the improved performance of our Voronoi foam in comparison with classical topology optimization approaches and demonstrate its advantages in various settings.