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Future vehicles are connected, autonomous and shared platforms that render a multitude of services in our everyday lives. The vehicle's driving function will ultimately converge to a commodity sourced by superstructure manufactures that develop service-oriented functionality. For the early stage vehicle concept design, this new functionality imposes a new complexity for superstructure engineers. Novel service offerings translate into new functional requirements and technical components that need to be optimally sized and positioned inside the vehicle package to increase the amount of service units that can be supplied to the customer. Today, vehicle concept design optimization only focuses on powertrain components. In this paper, we introduce a novel two-step package design optimization for vehicle superstructures. First, functional requirements are derived from service units, the smallest unit of value to the vehicle-based service customer. We then develop component weight and size regression models from data retrieved from online warehouses. Components and their installation constrains are represented by scalable containers. A combined packing heuristic and parameter optimization arranges the containers within the vehicle's available installation space and created layout alternatives. We apply this procedure to a real case study based on the aCar, a light electric utility vehicle for rural sub-Saharan Africa. This is a first step to enable superstructure manufactures to design and optimize vehicle concept designs based on service capacity. [ABSTRACT FROM AUTHOR]

Irregular-shaped particle packing is important to simulate the cement paste microstructure. However, the efficiency of current packing models is relatively low. This study proposes a novel packing algorithm named the Mesh Optimization Packing (MOP) model inspired by the VOX and extent overlap box (EOB) methods. The MOP model's performance in terms of accuracy, uniformity, and randomness were evaluated. Meanwhile, compared to the Anm model 2.0 and the VOX model, the MOP model excels in simulating the initial microstructure of cement paste with high cement volume fractions. When the cement volume fraction is 56.03 %, the VOX model requires 124.68 h, while the MOP model only takes 18.80 h. By adding uniform-thickness shells to irregular-shaped particles, the MOP model integrates with the HYMOSTRUC3D-E model to simulate the evolution and uniaxial stretching process of the cement paste microstructure. This innovative modelling approach offers a promising solution for future simulations of cement paste microstructure. [Display omitted] • A new packing algorithm for irregular-shaped particles was proposed and evaluated. • The algorithm efficiently simulates the initial microstructure of cement paste. • The evolution of cement paste microstructure can be simulated by the algorithm. [ABSTRACT FROM AUTHOR]

In recent years, many wooden houses in Japan are built using pre-cut timbers. Pre-cut timber is material for residential buildings, such as roofs, floors, and pillars, whose joints have been pre-processed. As the number of carpenters has decreased, the demand for pre-cut timber has increased. However, since the number of pre-cut timber production factories decrease, improving the productivity of those factories is an urgent issue. From this background, we are developing an algorithm for packing formation support systems to improve packing work productivity. In this paper, we propose the algorithm for packing formation of pre-cut timbers using the iterative local search with Or-opt, and discuss numerical experiments results. [ABSTRACT FROM AUTHOR]

The internal structure of composite materials is usually composed of a continuous matrix with dispersed particles. To simulate the spatial distribution of particles, the random sequential addition algorithm (RSA) is commonly used. The RSA using continuous geometric function is difficult to achieve a high packing density in allowable computer time and time-consuming in the case of irregularly shaped aggregates, such as in mortar and concrete systems. In this work, a geometrical model, named as VOX, is introduced to deal with 3D irregularly shaped particles. The model applies the voxel-based overlap determination in the RSA to improve the efficiency and packing density. Also, the model is applicable to the complex boundary conditions of any geometry and provides high-quality triangle meshes valuable for finite element analysis. The mortar and concrete cubes with real-shape particles are simulated, in which the packing density is increased to 65% and 51%, respectively. The VOX model successfully packs over 150,000 real-shape aggregates into the steel cage in a full-size reinforced concrete beam model on a desktop machine. Particle shape significantly affects the packing density in the RSA and the sphericity is recommended as an indicator. The particles with higher sphericity can achieve denser packing under the same effort of attempts. Real-shape gravel used in this study behaves similarly with regular octahedron because of the similar sphericity. [ABSTRACT FROM AUTHOR]

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Concrete has a random and complex microstructure, the mesh generation of which could be challenging and time-consuming. This research presents a numerical procedure for morphology generation and level set representation of realistic cementitious microstructures without meshing the internal material interfaces. Central to the proposed numerical method is the exploitation of a vector level set function in the description of arbitrarily shaped aggregate inclusions, which allows bypassing the orthogonal projection operation on the inclusion interface as well as the determination of the outward normal. The proposed level set method is then coupled to the extended finite element method to simulate crack propagation in cement-based materials. To realistically simulate the microstructure of concrete, an improved approach that is capable of reproducing the complex geometric shape and surface texture of aggregates is proposed. To enhance the computational efficiency, a packing algorithm that mimics the settling of soil particles and enables dense aggregate packing patterns is developed to speed up the process of placing the generated aggregates into representative volume elements. After that, a series of numerical experiments are conducted to evaluate the accuracy and efficiency of the new technique. The evaluation demonstrates the effectiveness and potential of the proposed method. [ABSTRACT FROM AUTHOR]

A new set of algorithms is introduced for the virtual reconstruction of heterogeneous material microstructures, in which morphologies of embedded particles/fibers are explicitly represented. As a pre-processing phase, a shape library containing morphologies of heterogeneities, parameterized in terms of Non-Uniform Rational B-Splines (NURBS), is extracted from digital data such as micro-computed tomography images. Two packing algorithms are then introduced to reconstruct an initial (raw) periodic microstructure: In the first approach, a set of hierarchical bounding boxes approximating particle shapes are employed to check for overlap. The second approach, which is specialized for fibrous microstructures, uses the NURBS representation of fiber centerlines during the packing process. An optimization phase is applied to build the final microstructural model, relying either on the Genetic Algorithm to selectively eliminate some of the inclusions or their sequential relocation within the raw microstructure. The objective functions of this optimization phase are designed to replicate the target statistical microstructural descriptors such as the volume fraction, size distribution, and spatial arrangement of inclusions. Several example problems are presented to show the application of these algorithms for synthesizing various heterogeneous microstructures, as well as their finite element modeling and simulation. [ABSTRACT FROM AUTHOR]

The paper proposes a way to examine whether cervical cells qualify as normal or abnormal on the basis of phase profiles, and to subsequently perform local fractal descriptions of their three dimensional holographic images. The method is an alternative tool to discriminate among normal and abnormal cervical cells by exploiting the whole image of the cell not only limited zones like random cross sections. The empirical findings indicate correlation between cross sectional phase profile and fractal characterisation. The results are useful for developing cell counting algorithms based on Bayesian programming. [ABSTRACT FROM AUTHOR]

This paper describes a numerical package for simulating stationkeeping operations of an offshore vessel in floating sea ice. The software has found broad usage in both academic and industrial projects related to design and operations of floating structures in the Arctic. Interactions with both intact and broken ice conditions can be simulated by the numerical tool, but the main emphasis is placed on modelling managed ice environments relevant for prospective petroleum industry operations in the Arctic. The paper gives a thorough description of the numerical tool from both theoretical and software implementation perspectives. Structural meshing, ice field generation, multibody modelling and ice breaking aspects of the model are presented and discussed. Finally, the main assumptions and limitations of the computational techniques are elucidated and further work directions are suggested.

The determining of efficient packaging sizes is a key factor in saving material and transportation costs and also in reducing packaging waste. By analyzing the range of items and their contribution to sales-relevant order structures of a globally operating mail order company, a simplified packing algorithm is proposed. In combination with well-known methodologies, this heuristic provides near optimal solutions improving current packaging of eCommerce companies. It is shown that simple, practical heuristics are sufficient to achieve average material savings of more than 10 %. In order to find efficient packaging sizes, a set of them is generated by discretization of packaging dimensions. Given the set of orders and the set of packaging sizes, a p-median approach is applied to find a specified number of optimal, demand-related packaging sizes. [ABSTRACT FROM AUTHOR]

As key parameters of modeling iron ore pellet drying and induration process, the properties of a packing bed are calculated by our proposed method. Derived from realistic spheres-dropping phenomena, the dropping and rolling rules make the moving sphere finally reach its minimum gravitational potential energy. Furthermore, the plastic deformation of green pellets and mechanic vibration are also considered in the model. The model is based on the laws of mass and heat transfer, physical process, and chemical reaction. The partial differential equations of the process kinetic model involve derivatives in time and bed depth. Comparing the results with measured data proves that the model can be used for optimizing the iron ore pellet induration process and as an effective tool for other, similar thermodynamic process simulations. [ABSTRACT FROM PUBLISHER]

Soil–water characteristic curve (SWCC) is widely used for obtaining mechanical and hydraulic properties of unsaturated soils, such as shear strength, deformation, permeability, and flow. An innovative approach, where a meso-scale medium is generated based on particle size distribution and void ratio of non-plastic soils, for estimating the drying SWCC is developed. With application of the finite difference and Newton-Raphson (Jacobian) approximations, the air-entry pressures of pore bodies in inter-particle medium (micro-scale) are determined and implemented in drainage simulation of the medium. The volumes of drained pore bodies and subsequently developed liquid bridges after each suction iteration are calculated and plotted. Eventually, homogeneity of the developed packing algorithm, parametric study, comparison of the simulated drying SWCC to experimental and estimation results as well as computational performance of the developed MATALB code is presented and discussed. It is shown that, the proposed method results in much superior approximation of SWCC in comparison to the two major estimation methods (Arya and Paris, 1981; Fredlund and Wilson, 1997) and due to its accuracy and time efficiency, the algorithm can even be a viable option for replacing the tedious experimental methods. [ABSTRACT FROM AUTHOR]

Static Random Access Memory (SRAM) based Field Programmable Gate Array (FPGA) is widely applied in the field of aerospace, whose anti-SEU (Single Event Upset) capability becomes more and more important. To improve anti-FPGA SEU capability, the registers of the circuit netlist are tripled and divided into three categories in this study. By the packing algorithm, the registers of triple modular redundancy are loaded into different configurable logic block. At the same time, the packing algorithm considers the effect of large fan-out nets. The experimental results show that the algorithm successfully realize the packing of the register of Triple Modular Redundancy (TMR). Comparing with Timing Versatile PACKing (TVPACK), the algorithm in this study is able to obtain a 11% reduction of the number of the nets in critical path, and a 12% reduction of the time delay in critical path on average when TMR is not considered. Especially, some critical path delay of circuit can be improved about 33%. [ABSTRACT FROM AUTHOR]

Abstract: A modified collective rearrangement algorithm, based on the sphere-assembly representation of the particle shape, is presented for simulating random packings of nonspherical particles and arbitrary shapes. Compared to other collective rearrangement methods, the modification introduced by this algorithm consists in i) avoiding the particle-to-container shrinking procedure by allowing particles to sequentially settle down and ii) in a stability constraint applied to all the particles in the packing. The coupling of these criteria ensures that all the particles are stable and contacting each other, allowing for an unambiguous detection of contacts, which is important in the evaluation of the effective properties desired in many engineering applications, such as percolation thresholds and effective conductivity. The effect of the internal parameters of the algorithm is investigated, showing that random close packings can be obtained. The algorithm is applied to simulate packings of rigid ellipsoids and cylinders with different aspect ratios, which are compared with simulation results provided by other packing algorithms, showing the consistency of our method. Simulations of inter-penetrating particles, mixtures of particles with different shapes and packings of agglomerates are shown, which confirm the applicability of the method to a broad range of packing problems of practical interest and, in particular, for fuel cell applications. [Copyright &y& Elsevier]

A methodology for estimating the optimal distribution of photovoltaic modules with a fixed tilt angle in ground-mounted photovoltaic power plants has been described. It uses Geographic Information System, available in the public domain, to estimate Universal Transverse Mercator coordinates of the area which has been selected for the installation of the photovoltaic plant. An open-source geographic information system software, Q G I S , has been used. The estimation of the solar irradiance takes into account the variations in the local cloud cover distribution. The optimization process is considered to maximize the amount of energy absorbed by the photovoltaic plant using a packing algorithm (in Mathematica™ software). This packing algorithm calculates the shading between photovoltaic modules. This methodology can be applied to any photovoltaic plant. Different rack configurations and tilt angles are incorporated in the study to account for the characteristics of the irregular shape of the land. The most used rack configurations in photovoltaic plants are the 2 V × 12 configuration (2 vertically modules in each row and 12 modules per row) and the 3 V × 8 configuration (3 vertically consecutive modules in each row and 8 modules per row). Codes and standards have been used for the structural analysis of these rack configurations. For this purpose, the wind loads, the snow loads, the weight of the structure, the weight of the photovoltaic modules, and combinations thereof have been calculated. This analysis has been performed with AutoDesk Robot Structural Analysis software for the different rack configurations. A detailed cost analysis of the most used rack configurations in photovoltaic plants has been presented. The levelized cost of the produced electricity efficiency is calculated for each rack configuration. The methodology has been applied in Sigena I photovoltaic plant located in Northeast of Spain. The current rack configuration used in this photovoltaic plant is the 2 V × 12 configuration with a tilt angle of 30 (°). The configurations 3 V × 8 configuration with a tilt angle of 14 (°) and 2 V × 12 configuration with a tilt angle of 22 (°) are the best options proposed by the optimization algorithm. The results show that the 3 V × 8 configuration with a tilt angle of 14 (°) increases the amount of energy captured by up to 32.45% in relation to the current configuration of Sigena I photovoltaic plant with a levelized cost of the produced electricity efficiency of 1.10. In the other hand, the 3 V × 8 configuration increases the amount of energy captured by up to 19.52% in relation to the 2 V × 12 configuration with a tilt angle of 22 (°) with a levelized cost of the produced electricity efficiency of 1.05. The 3 V × 8 configuration is the one which has the lowest cost for the same number of photovoltaic modules. The 2 V × 12 configuration with a tilt angle of 30 (°) increases the cost by up to 32.48% in relation to a 3 V × 8 configuration with a tilt angle of 14 (°). • A new methodology for an optimum design of ground-mounted PV power plants. • The 3V × 8 configuration is the best option in relation to the total energy captured. • The proposed solution increases the energy a 32% in relation to the current one. • The 3V × 8 configuration is the cheapest one. • The LCOE efficiency of the 3V × 8 configuration is the best: 1.10. [ABSTRACT FROM AUTHOR]

A simulation algorithm was developed for modeling the dense packing of large assemblies of particulate materials (in the order of millions). These assemblies represent the real aggregate systems of portland cement concrete. Two variations of the algorithm are proposed: sequential packing model and particle suspension model. A developed multicell packing procedure as well as fine adjustment of the algorithm's parameters were useful to optimize the computational resources (i.e., to realize the trade-off between the memory and packing time). Some options to speed up the algorithm and to pack very large volumes of spherical entities (up to 10 million) are discussed. The described procedure resulted in a quick method for packing of large assemblies of particulate materials. The influence of model variables on the degree of packing and the corresponding distribution of particles was analyzed. Based on the simulation results, different particle size distributions of particulate materials are correlated to their packing degree. The developed algorithm generates and visualizes dense packings corresponding to concrete aggregates. These packings show a good agreement with the standard requirements and available research data. The results of the research can be applied to the optimal proportioning of concrete mixtures. [ABSTRACT FROM AUTHOR]

This paper on the fundamental structural properties of shell-side packed columns presents an investigative study using a novel packing algorithm with the aim of validation against experimental results. The novel contribution in the predictive approach employed is the digitalisation of particles, container and packing space to generate complex life-like stochastic packing structures of particulate systems at relatively high speed (when compared to traditional vector-based approaches) which are comparable with experimentally packed beds without need for further conversion of numerical data. A variety of packed column simulations, comprising more complex beds than often seen in the literature, namely shell-side beds with increasing complexity of internal structure and packed with spherical particles, have been undertaken and the resulting averaged numerical data compared like-for-like with experimental results with key trends reproduced. The overall aim of this work is to demonstrate the usefulness of the technique and associated computer code as an engineering aide for research, design and optimisation of the performance of packed bed systems of any geometric complexity in terms of packing structure, as well as to highlight possible areas for further development of the code. [Copyright &y& Elsevier]

The dense packing of particulate assemblies is an enduring theoretical and practical problem. In spite of its apparent simplicity, this problem still remains challenging. Recent progress in the performance of computers boosted the development and realization of a number of effective packing algorithms. Yet, because of the complexity of the problem, many of existing methods have difficulties in handling large numbers of particles. A simulation model is proposed to overcome this. The model assumes that the centers of the spheres are randomly generated at the intersections of a cubic lattice. The largest possible spheres are packed first; subsequent spheres are limited by the set of minimum diameters, which is specified by the constraints imposed by two major parameters imitating the compaction gradient: a reduction coefficient and the number of packing trials. Importantly, the packing arrangements are not defined by the initially specified particle size distribution (as considered by many existing packing algorithms), but rather the most dense particle size distribution, along with the corresponding value of packing degree, is generated by the proposed model. Based on these criteria, a very fast algorithm was developed for simulating of the dense packing of large assemblies of particulate, spherical material (in the order of millions of particles). Using this approach, the influence of geometrical parameters and model variables on the degree of packing and the corresponding distribution of particles was studied. [Copyright &y& Elsevier]