Layout Geometry Research Articles

Layout Optimization of Wave Energy Park Based on Multi-Objective Optimization Algorithm

Abstract In this paper, both semi-analytical method and numerical simulation is applied to investigate the hydrodynamic behavior of large arrays of point-absorber wave energy converters (WECs). To analyze wave interactions among multiple WECs within an array, a semi-analytical model is developed based on the potential flow theory and the matched eigen-function expansions method. The fluid domain is divided into two kinds of regions: interior regions underneath the cylinders and an exterior region surrounding all the cylinders. The matched eigenfunction expansions method is employed to solve the radiation potential problem in each domain, and the hydrodynamic coefficients and motion response of the cylinders in the array are evaluated. To validate the accuracy of the semi-analytical method, WAMIT is adopted to simulate the wave energy park numerically and compared with the results by the semi-analytical model. The hydrodynamic characteristics and power absorption performance of the WECs within the wave energy park are analyzed. The power performance of a wave energy park is studied as functions of layout geometry, incident wave direction and separation distance between WECs respectively. Finally, MOPSO based on a surrogate model is used to optimize the layout of wave energy array.

Fruit grading system by reconstructed 3D hyperspectral full-surface images

Conducting hyperspectral imaging of fruit' entire surfaces while simultaneously evaluating their physical properties, such as volume and mass, can provide a richer dataset for comprehensive fruit classification. For this purpose, a fruit grading system using 3D hyperspectral full-surface images is developed, which is based on multi-view imaging of mirrors in the hardware structure design and relies on the virtual volume intersection (VI) algorithm and texture technology in software design. During the design process, a mathematical model for the mirror layout and system geometry parameters is established to determine the system's layout for scanning the entire surface of the sample. In practical applications, a prototype with 28 channels ranging from 400 to 1000 nm is developed for pear samples based on a sub-component control system, a spherical-cap cavity with flashing multi-color LEDs, and multiple side mirrors. The results obtained from this prototype reveal that the predicted volume (R2=96.18%) and mass (R2=98.18%) exhibit a high correlation with measured results and the hyperspectral data between bruised and normal pears is a significant difference. A dataset of pears of three qualities (large, small, and bruised) is prepared for comprehensive classification and resulting in an effective grading (95.33%), which shows that the proposed system is a potential solution for comprehensive fruit quality classification.

Possibility of YH1.85 and MgO–BeO as a moderator in high temperature reactors

This study compared the neutronic behaviors of the graphite material utilized in standard HTGR reactors to those of yttrium hydride and MgO–BeO moderator materials using the OpenMC and Serpent Monte Carlo codes. keff values for various fuel/moderator ratios in a TRISO particle-embedded moderator matrix were computed. The effect of packing fraction was then investigated, and the keff values for different packing fractions were compared for the MgO–BeO, YH1.85, and C (graphite) moderator matrices in the geometry layout containing randomly placed TRISO particles. In contrast to graphite and MgO–BeO moderators, the keff values for YH1.85 moderator indicated that a very small moderator volume is adequate for thermalization. We also investigated how temperature reactivity feedback impacts different packing fractions. In the temperature reactivity feedback analysis, the overall temperature coefficient was determined to be negative for all moderators. The temperature feedback coefficient for the fuel with the YH1.85 moderator was found to be significantly lower in magnitude than for the system with graphite and MgO–BeO. The burnup findings revealed that graphite and MgO–BeO behaved similarly; however, YH1.85 was shown to be useful only at very low moderator/fuel ratios. With typical HTGR power density, the fuel cycle time for YH1.85 was found to be around 516 days. Also, while the YH1.85 moderator system reduces the risk of proliferation by producing small amounts of 239Pu and 241Pu, it was determined that it is more suitable for small modular and microreactor designs for high-temperature reactors with low moderator/fuel ratio requirements.

Does a row of objects comprise a boundary? How children miss the forest for the trees in spatial navigation.

Unlike children's early ability to navigate by continuous boundaries, their ability to extract geometric information from an array of objects emerges gradually over childhood. To investigate children's developing representation of object arrays for navigation and its relation to their mental representation of the global spatial layout, reorientation behavior was tested in 146 children (4-9 years, 78 male children and 68 female children, Italian) with rectangular arrays made up of 20 objects. Posttest questions on children's spatial language and their mental and pictorial representation of the environment were administered. Although children of all ages navigated by the geometry of continuous boundary-like arrays, they only succeeded with separated object arrays at around 7 years of age. This developmental change was predicted by children's individual ability to extract the abstract geometry of the spatial layout in a two-dimensional picture of the room. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

MM-Tap: Adaptive and Scalable Tap Localization on Ubiquitous Surfaces With mm-Level Accuracy

Transforming physical surfaces into virtual interfaces can extend the interaction capability of many exciting metaverse applications in the future. Recent advances in vibration-based tap sensing show promise for this vision using passive vibration signals. However, current approaches based on Time-Difference-of-Arrival (TDoA) triangulation suffer the impact of fluctuant wave velocity due to the dispersive and heterogeneous nature of solid mediums, failing to meet the performance requirement for practical use. In this paper, we present MM-Tap, a vibration-based tap localization system that can transform ubiquitous surfaces into virtual touch screens with low overhead. A novel localization scheme is proposed based on the finding of spatio-temporal mapping between tap locations and TDoA values, which pushes the accuracy limits of vibration-based tap sensing from unstable cm-level to mm-level. We investigate the geometry of the sensor layout and design a model-based method to synthesize tap data, which enables MM-Tap to adapt to various surface materials and respond to arbitrary sensing scales after a few seconds of calibration. We combine MM-Tap with a COTS projector and facilitate a digitally augmented surface where users can play video games with low latency.

Comparative analysis of 3‑D modeling programs KOMPAS-3D and AUTODESK INVENTOR using the example of the «lever assembly» assembly unit

This article discusses the operation «layout geometry» in the COMPASS-3D modeling program and adaptive technology in the Autodesk Inventor program using the example of an assembly unit. As a result of the work, a working prototype of the assembly unit in question was made. Autodesk Inventor is Autodesk»s three — dimensional solid-state and surface parametric design (CAD) system designed to create digital prototypes of industrial products. COMPASS-3D is a Russian import — independent three-dimensional design system, which is widely used for the design of products of the main and auxiliary industries in mechanical engineering, instrumentation, aircraft, shipbuilding and machine tool construction.

Concurrent topology optimization of shells with pattern-guided infills for intuitive design and additive manufacturing

This paper introduces a systematic design optimization approach for shells with pattern-guided infills, aiming to address both intuitive design requirements and considerations for additive manufacturing. The approach utilizes a density-based topology optimization method and assigns two sets of design variables to distinctly define the base, coating, and infill structures. By evolving the solid shells and enriched infills concurrently, the design optimization process ensures a cohesive integration of both components. To guide the infill design towards matching the geometrical features of a predefined pattern, a geometrical constraint is imposed on the infill field. Enhanced by an updated and approximate volume constraint, the infill materials with prescribed appearance performances are accordingly distributed in the base region. The simultaneous optimization of shell geometry and infill layout is then performed within the framework of minimum compliance topology optimization. A range of numerical results illustrate the effectiveness and robustness of the proposed approach. The topology optimized results demonstrate that a given pattern can directly control the design features of the infill in a visually explicit manner and the shell-infill composites ensure convenient manufacturability.

Numerical simulation of large-scale pillar-layouts

A number of shallow coal or hard rock mines employ pillar mining systems as a strategy for roof failure control. In certain platinum mine layouts, pillars are designed to 'crush' in a stable manner as they become loaded in the panel back area. The correct sizing of pillars demands some knowledge of the pillar strength and the overall layout stress distribution. It is particularly important to understand the impact of the layout geometry on the effective regional 'stiffness' of the rock mass around each pillar. An important design strategy is to model relatively detailed layout configurations which include a precise representation of the local pillar layout geometry and to analyse multiple mining scenarios and extraction sequences to select optimal pillar sizes and barrier pillar spacing. Although computational solution techniques are now impressive in terms of run time efficiency, a major difficulty is often encountered in assigning suitable material properties to the pillars and in devising an effective material description of the layered rock strata overlying the mine excavations. This paper outlines an efficient numerical strategy that can be used to assess large-scale pillar layout performance while retaining the ability to modify individual pillar constitutive behaviour. The proposed method is applied to selected layouts to compare estimated average pillar stress values against values determined by detailed modelling and against observed behaviour.

Inverse design of plasmonic nanoantenna using generative adversarial network

The local surface plasmon resonance (LSPR) effect has been widely used in various nanophotonic applications. However, because the LSPR effect is highly sensitive to the structure and geometry, it is desirable to efficiently search viable geometries for predefined local field enhancement spectrum. Herein we present a generative adversarial network-based LSPR nanoantenna design scheme. By encoding the antenna structure information into an red-green-blue (RGB) color image, the corresponding nanoantenna structure can be inverse-designed to achieve the required enhancement spectrum of the local field. The proposed scheme can accurately offer the multiple geometry layout for the customized specific spectrum in seconds, which could be beneficial for fast design and fabrication of plasmonic nanoantenna.

Neutronic Activity for Development of the Promising Alternative Water-Cooled DEMO Concepts

An emerging breeding blanket that fulfills performance criteria, meets the safety requirements, and is reliable enough to meet the plant availability is a challenging issue that assumes complex studies involving numerous neutronic analyses based on the Monte Carlo simulations with MCNP code. Two different concepts are now candidates to be implemented as a driver blanket for DEMO fusion reactor: WCLL (Water-Cooled Lithium Lead) and HCPB (Helium-Cooled Pebble Bed). The current R&D work within the EUROfusion DEMO project is concentrated on a search for the new water-cooled blanket layouts: a deep upgrade of the WCLL blanket to ensure a sufficient tritium breeding capability and an elaboration of the hybrid concept coupling technological advantages of water coolant, lead neutron multiplier, and ceramic breeder. To this end, very detailed, fully heterogeneous MCNP geometry models were developed for the newest designs of the WCLL-db (WCLL-double bundle) and WLCB (Water-cooled liquid Lead Ceramic Breeder) DEMO blankets to verify the new engineering solutions. This makes rigorous calculations possible to find an optimal breeder blanket layout. The basic response, tritium breeding ratio (TBR), was assessed for both concepts, and it appeared to be TBR = 1.16 for the WCLL-db and TBR ≤ 1.13 for the WLCB DEMOs, respectively. Several geometry layouts of the WLCB breeder blanket were investigated to reach the TBR sufficient for a sustainable tritium fuel cycle. Two promising novel solutions were suggested to enhance the tritium breeding performance of the WLCB blanket and to achieve TBR ≥ 1.16: heavy water coolant and an advanced breeder ceramic. Various nuclear safety aspects of the technologies utilized in both blanket concepts are addressed in this work to facilitate engineering decisions aimed at the consolidated blanket design for the upcoming DEMO reactor.

In-depth understanding of boosting salinity gradient power generation by ionic diode

Ionic diodes constructed with asymmetric channel geometry and/or charge layout have shown outstanding performance in ion transport manipulation and reverse electrodialysis (RED) energy collection, but the working mechanism is still indistinct. Herein, we systematically investigated RED energy conversion of straight nanochannel-based bipolar ionic diode by coupling the Poisson-Nernst-Planck and Navier-Strokes equations. The effects of nanochannel structure, charging polarity, and symmetricity as well as properties of working fluids on the output voltage and output power were investigated. The results show that as high-concentration feeding solution is applied, the bipolar ionic diode-based RED system gives higher output voltage and output power compared to the unipolar channel RED system. Under optimal conditions, the voltage output of the bipolar channel is increased by ∼100% and the power output is increased by ∼260%. This work opens a new route for the design and optimization of high-performance salinity energy harvester as well as for water desalination.

Microfluidic separation of particles by synergistic effect of geometry-induced hydrodynamics and magnetic field

Microfluidic combined with magnetic field have been demonstrated to be the promising solutions for fast and low-damage particles separation. However, the difficulties in the precise layout of magnets and accurate prediction of particle trajectories lead to under and over separation of target particles. A novel particle separation lab-on-chip (LOC) prototype integrated with microstructures and micropolar arrays is designed and characterized. Meanwhile, a numerical model for the separation of magnetic particles by the synergistic effect of geometry-induced hydrodynamics and magnetic field is constructed. The effect of geometry and magnetic field layout on particle deflection is systematically analyzed to implement accurate prediction of particle trajectories. It is found that the separation efficiency of magnetic particles increased from 50.2% to 91.7% and decreased from 88.6% to 85.7% in the range of depth factors from 15 µm to 27 µm and width factors from 30 µm to 60 µm, respectively. In particular, the combined effect of the offset distance of permanent magnets and the distance from the main flow channel exhibits a significant difference from the conventional perception. Finally, the developed LOC prototype was generalized for extension to arbitrary systems. This work provides a new insight and robust method for the microfluidic separation of magnetic particles.

Heat and species map prediction for the generic MEA using an air node model derived from high level requirements

Current developments to implement the More Electric Aircraft (MEA) result in a fundamental change of the aircraft systems architecture. Components may be resized or new components may be introduced. This results in new challenges for the thermal management and safety assessment of systems and therefore parametric and fast simulations tools will become crucial to explore the entire design space. The effects of component heat dissipation on airflow in the aircraft fuselage can be qualified using a zonal simulation model. Zonal airflow models subdivide the indoor space into typically 102 zones exchanging air. This allows to predict the impact of systems locations, ventilation and cooling strategies on the thermal management and safety considerations in an early design stage. This paper presents the setup of such an aircraft zonal model based on high-level requirements for a MEA of regional airplane size. These requirements cover the number of passengers, the flight profile and system components to be integrated, like e.g. the battery. Additional requirements are derived from standards for example providing information on required airflow rates and temperatures in the cabin. These requirements are translated into a geometry, ventilation pattern and systems layout. The model application is demonstrated on the example of the safety consideration in case of a battery failure leading to exhaust of harmful gas. This is done by comparing the gas dispersion for two different battery positions in the aircraft.

Incremental design process for vehicle structural components using thermoplastic-based composites: A simulation-guided approach for door anti-intrusion beams

The design of safety-related structural components in automobiles is a critical phase. Most car manufacturers are aiming at reducing vehicle weight considering continuous fiber-reinforced thermoplastics as candidate to replace metal-based structural components. However, this replacement cannot compromise the safety level already achieved by metal-based designs. A good example is the side door anti-intrusion beam, which is a passive safety component to protect the passengers under a lateral impact. This paper presents an incremental design process to achieve a functional side door anti-intrusion beam fully made of glass fiber reinforced thermoplastic conceived to replace metal-based ones. The reader is guided along the design challenges, where the mechanic-based reasons to adapt the part geometry and composite layout are explained in detail. This incremental design process uses a fully FEM-based approach allowing to reach a standard-defined absorbed energy of 1000 J in a lateral collision. From the simulation analysis, it was found that by implementing essential modifications in the beam’s cross-section corrugation, the damage progression can be slowed down leading to an increase of absorbed energy. Additionally, the enhancement of one extra ply in the proper direction solves severe fracture in the clamping area. The final composite design not only performs similarly to its metal-based counterpart, but also considers aspects of production feasibility. This trip along the design process concludes with the production of the simulate-designed component and its effectiveness under lateral impact is demonstrated. To meet the safety regulations, the model is thoroughly validated against the real impact test by analyzing the response in force, intrusion, energy and damage.

Focus on software, data acquisition, and instrumentation

Focus on software, data acquisition, and instrumentation

Seismic capacity and performance of code-conforming single-story RC precast buildings considering multiple limit states and damage criteria

The seismic capacity and performance of code-conforming precast buildings is assessed in the study. The case study consists in single-story precast buildings designed according to Italian building code considering low to high seismicity sites and varying both geometry layout and soil conditions. The seismic behavior of the buildings is assessed through multiple-stripe analyses performed through nonlinear three-dimensional modeling. Fragility of the buildings is computed by considering several methods, and performance evaluation is based on capacity margin ratios, failure probabilities, and reliability indexes. Damage limitation, life safety prevention, and near collapse prevention performance levels are considered by accounting for multiple damage criteria and damage states, including both local and global approaches and both ductile and brittle failure of beam-to-column connections.The paper provides guidance for implementation of seismic capacity and performance evaluation of precast buildings according to latest advances, considering both European and US approaches. The study proves that the current code prescriptions might not supply adequate seismic performance, especially in the case of more critical soil conditions (i.e., C soil type compared to A soil type). A relatively critical performance was observed for damage limitation and life safety prevention performance levels, whereas collapse performance of the buildings was adequate. The extremely critical condition associated with brittle failure of the beam-to-column connection was also confirmed. The study stresses the need for an enhancement of current design requirements and highlights the need for further investigation into the adequacy of seismic performance of precast buildings and reliability of related code-conforming design.

Electromigration-induced void evolution and failure of Cu/SiCN hybrid bonds

The realization of high interconnect densities for three-dimensional integration demands development of new wafer-to-wafer bonding approaches. Recently introduced Cu-to-Cu wafer-to-wafer hybrid bonding schemes overcome scaling limitations, but like other Cu-based interconnect structures, they are prone to electromigration. Migration and growth of voids, induced by electromigration and mechanical stress, cause Cu-to-Cu hybrid bonds to fail. A comprehensive modeling approach is required to fully understand the complex dynamics of voids with their influencing factors, such as current density, temperature, and mechanical stress. In this work, we utilize such a modeling approach to perform studies of void migration through Cu-to-Cu hybrid bonds. The calculated velocities of the evolving void surface fully correspond to the experimentally observed behavior of voids migrating from the lower pad to the upper diffusion barrier of the upper pad, where they cause electrical failure. The migration velocity of a void in the upper pad is 20% higher than the migration velocity of a void in the bottom pad. Unbalance of the normal velocity distribution at the void surface leads to the transformation of the originally ellipsoid void into a teardrop shape. The simulations provide full insight in the impact of layout geometry, material properties, and operating conditions on void dynamics. In addition, the results enable targeted adjustments of the influencing factors to inhibit void migration and growth in order to delay or to fully prevent Cu-to-Cu hybrid bond failure.

The excellent performance of β-Ga2O3 Schottky photodiode under forward bias and its application in solar-blind ultraviolet communication

In this work, the planar β-Ga2O3 Schottky photodiodes on the sapphire substrates were manufactured by conventional photolithography and lift-off processes. Au and Ti/Au were used as Schottky and Ohmic contacts. After optimizing the geometry layout of β-Ga2O3 Schottky photodiode, R increased by 120%, EQE enhanced by 896.81% and D* gotten a 1540.88% increase. Particularly, β-Ga2O3 Schottky photodiode had exhibited the abnormally excellent performance under forward bias, contrary to most of conventional UV photodetectors. The origin of abnormally excellent performance in β-Ga2O3 Schottky photodiodes under forward bias have been researched systematically. Combined experiments with DFT calculations, we have attributed the ultra high EQE in β-Ga2O3 Schottky photodiode to its unique band structure. While the large photo-to-dark current ratio and D* under forward bias originate from deep-state intrinsic defects of β-Ga2O3. At last, the solar-blind ultraviolet communication system based on β-Ga2O3 Schottky photodiode was achieved and the message, “Hello, HIT!”, was successfully transmitted.

Illumination guided sparse geometry optimization for target-oriented full-waveform inversion: An ocean bottom node synthetic study

For full-waveform inversion (FWI) with sparse survey layout, it is crucial to optimize the source and receiver geometry toward full-wave illumination. We propose a sparse geometry optimization method and workflow for target-oriented FWI using finite-frequency illumination analysis. The frequency-dependent impact of a source-receiver pair to the wavefield sensitivity kernel and diagonal terms of approximate Hessian matrix are derived under visco-acoustic model assumptions. Based on the reciprocity principle, we use virtual sources in target zone to efficiently calculate the Green's function and illumination from acquisition surface. Optimal locations of sparse receivers are determined by comparing band-limited illumination at reference stations and their surrounding region through an illumination attribute scan. FWI model residual errors are used to evaluate the performance of optimized geometry layout for a given target zone. The performances of different geometries are compared to determine a suitable frequency band for FWI geometry optimization. Synthetic deep water model and ocean bottom node acquisition geometry are used to verify the feasibility of the workflow. Numerical tests in target-oriented FWI show that optimized geometry with constraints of band-limited illumination below10 Hz has better performance than that above 10 Hz. An extension of our geometry optimization method to sparse source configuration is straightforward.

Numerical analysis of intake port modification onto fluid flow pattern and flame propagation in particular combustion chamber

It is known for a long time that inlet port geometry has a great influence onto fluid flow pattern and flame propagation in spark ignition IC engines. In this paper only the initial results of the very complex study on the effects that proposed inlet port modification has onto the in-cylinder flow processes including the combustion stage, in particular. The study mentioned below incorporates state of the art multidimensional numerical modelling of reactive flow in the inlet port and combustion chamber geometry layout with moving boundaries of spark ignition IC engine with two valves. The main objective of this study is to investigate the possibilities for improvement the IC engine output characteristics through the inlet port modifications. Bearing in mind that flame propagation through unburnt mixture of spark ignition IC engine is primarily controlled by dint of turbulence diffusion, it is of prime importance for engine optimization to correctly identify the influence of certain types of organized flows onto the fluid flow pattern and flame propagation. The efforts for improvement have to be aimed on the type of organized flow or eventually their combination that is of prime importance for further development of the in-cylinder processes and combustion stage.