A particle-based dissolution model using chemical collision energy

We propose a new energy-based method for real-time dissolution simulation. A unified particle representation is used for both fluid solvent and solid solute. We derive a novel dissolution model from the collision theory in chemical reactions: physical laws govern the local excitation of solid particles based on the relative motion of the fluid and solid. When the local excitation energy exceeds a user specified threshold (activation energy), the particle will be dislodged from the solid. Unlike previous methods, our model ensures that the dissolution result is independent of solute sampling resolution. We also establish a mathematical relationship between the activation energy, the inter-facial surface area, and the total dissolution time - allowing for accurate artistic control over the global dissolution rate while maintaining the physical plausibility of the simulation. We demonstrate applications of our method using a number of practical examples, including antacid pills dissolving in water and hydraulic erosion of non-homogeneous terrains. Our method is straightforward to incorporate with existing particle-based fluid simulations

COILReef™ Wave Energy Dissipation Project

Within this Final Design Review (FDR) report, the COILReef™ Senior Project concludes with all updates reflecting results after testing. The COILReef™ is a device ideated by Cal Poly Professor Roger Benham. It aims to provide a removeable, low-cost solution to dissipating ocean wave energy, thereby reducing coastal erosion in sensitive areas. Current permanent solutions cost millions of dollars, take years to construct, and sometimes produce undesirable and unintended effects. The work presented in this document provides the foundational research, testing, and steps taken by the team to evaluate the feasibility of the COILReef™ design as a viable solution to reducing coastal erosion. The team developed an understanding of stakeholder needs/wants and current solutions for preventing coastal erosion through background research. The research also included a patent search and technical research pertaining to the subject. The team defined the problem statement and scope of work that will be assessed which includes various analysis techniques including a boundary diagram, Quality Function Deployment (QFD), Gantt chart, ideation, controlled convergence analysis, and Failure Modes and Effects Analysis (FMEA). A project timeline with key milestones was defined and a plan was created to meet deliverable deadlines throughout the duration of the project. To evaluate the feasibility of the COILReef™, the team executed theoretical simulation using CFD software as well as physical testing of prototypes in a waterpark wave pool as well as in a smallscale wave tank. The prototypes were built with high and low parameters for four design factors as follows: coil diameter, coil spacing, depth of placement, and incident angle of wave impact. The coil diameter was selected based on wave height, with the high parameter being equal to the incoming wave height, and the low parameter being equal to one half of the incoming wave height. The coil spacing dimensions were selected with a high parameter of eight inches, and a low of four inches. These parameters were selected intuitively with enough of a difference between the high and low to obtain a noticeable difference in the results. The high parameter for the depth of placement was at the water’s surface, and the low parameter was at a depth equal to one half of the wavelength where the orbital wave particle motion becomes negligible. Lastly, the incident angle of impact was chosen intuitively so that the coil was parallel to the incoming wave height for the low parameter, and at an angle of 45 degrees to the incoming wave for the high parameter. Based on tests conducted with all combinations of high and low parameters, the data suggested that a significant decrease in wave height was achieved by the prototype placed at the water’s surface parallel to the incoming wave with the diameter equal to the wave height and a coil spacing of four inches. It is the team’s recommendation that these results should be treated as preliminary and corroborated with further testing

Opérations topologiques pour la géomorphologie

National audienceLes paysages naturels résultent d'une succession d'événements géomorphologiques qu'il convient de simuler pour produires des résultats plausibles. En particulier, les changements topologiques doivent être pris en compte durant la formation de géométries complexes comme les arches, les ponts ou les tunnels naturels. Nous présentons une nouvelle approche pour simuler les évolutions géomorphologiques d'un terrain en 3D conçu comme un ensemble de volumes définis dans un modèle topologique, et décrivons un ensemble d'opérations atomiques afin de gérer les événements topologiques de manière robuste. Ces opérations somt combinées pour produire des scénarios d'évolutions plus complexes dans un modeleur basé sur les cartes généralisées, permettant de réduire le coût mémoire par rapport aux méthodes utilisant des voxels par exemple

Energy-based dissolution simulation using SPH sampling

A novel unified particle-based method is proposed for real-time dissolution simulation that is fast, predictable, independent of sampling resolution, and visually plausible. The dissolution model is derived from collision theory and integrated into a smoothed particle hydrodynamics fluid solver. Dissolution occurs when a solute is submerged in solvent. Physical laws govern the local excitation of solute particles based on kinetic energy: when the local excitation energy exceeds a user-specified threshold (activation energy), the particle will be dislodged from the solid. Solute separation during dissolution is handled using a new Graphics Processing Unit (GPU)-based region growing method. The use of smoothed particle hydrodynamics sampling for both solute and solvent guarantees a predictable and smooth dissolution process and provides user control of the volume change during the phase transition. A mathematical relationship between the activation energy and dissolution time allows for intuitive artistic control over the global dissolution rate. We demonstrate this method using a number of practical examples, including antacid pills dissolving in water, hydraulic erosion of nonhomogeneous terrains, and melting

Robotically Fabricated Ice Formwork: An Exploration on Casting Morphologically Programmed Complex Concrete Elements with Robotically Milled Ice Formworks

This document focuses on the exploration of casting complex concrete architectural elements with ice formwork. Replacing conventional concrete formwork with ice formwork,allows to produce architectural elements with complex geometries in a highly controlled off-site production process,with almost complete use of the mold material. Usingdigitallydrivenfabricationtoolssuchasaroboticarmmilling,the goal is to achieve 3d shapes made from one or more ice molds, able to be stacked, assembled and merged together in order to define architectural partitions. One of the main instigators of this research is the sustainability, showcased both through the usage of ice as a mold material that is 100% reusable, and the unique ability of the described process to produce topology optimized shapes in concrete, which reduces the use of this high carbon footprint material to to bare minimum. Ice formwork allows furthermore,to create bespoke shapes for every single element in an efficient way. This opens new avenues for architectural design and construction. This project uses a design based research methodology, where each physical iteration is carefully evaluated against the digital model, embracing morphological material programming

The odds are never in your favor: the form and function of American cinema's neoliberal dystopias

This article explores the ways in which dystopian cinema that emerged in the aftermath of the financial crisis of 2008 provided pointed critique of two aspects of neoliberalism’s economic and social policies: the deliberate imposition of precariousness across the working population which neutralizes dissent and forestalls collective opposition, and spatial segregation of rich and poor that is rigidly enforced. In In Time (Andrew Niccol, 2011), The Hunger Games (Gary Ross, 2012) and Elysium (Neil Blomkamp, 2013), the poor are plagued by uncertain employment, housing and healthcare, barely surviving under authoritarian regimes organized in favor of the rich and powerful. Despite the pointedness of this critique, however, this article also demonstrates how all three examples remain preoccupied with the possibility that heroic individuals can effect radical change, thereby providing a buttress to one of neoliberalism’s central animating constructs. In some senses, they indulge in a form of ‘cruel optimism,’ suggesting that precariousness and inequality could be overcome by individuals with special qualities, when real solutions to these problems seem so elusive. This article therefore questions the purpose of these films in the contemporary moment, where neoliberalism is in its death throes, but nothing coherent has yet emerged to replace it

Modélisation de terrains par primitives

National audienceNous proposons un modèle de terrain hiérarchique et compact permettant de représenter des scènes complexes. Ce modèle de représentation s'inspire des surfaces implicites à squelettes et définit une fonction d'élévation sous la forme d'un arbre de construction. Les feuilles sont des primitives décrivant des morceaux de terrains à différentes échelles (montagnes, fleuves, ...) et les noeuds internes sont des opérateurs de combinaison. L'élévation d'un point est calculée en traversant la structure d'arbre et en combinant les contributions de chaque primitive. La définition des feuilles et des opérateurs garantit que la fonction d'élévation résultante est Lipschitzienne, ce qui permet d'accélérer les calculs de visualisation en utilisant un algorithme de sphere tracing. Mots Clés : modélisation de terrains, phénomènes naturels, modélisation procédurale, surface implicite We propose a compact hierarchical procedural model that combines feature-based primitives to create complex continuous terrains. Our model is inspired by skeletal implicit surfaces and defines the terrain elevation by using a construction tree whose leaves are primitives describing terrain fragments, and whose inner nodes include operations that combine its sub-trees. The elevation of a point is evaluated by traversing the tree and by combining the contributions of each primitive. The definition of both leaves and operators guarantees that the resulting elevation function is Lipschitz which enables us to speed up sphere tracing and surface adaptive tesselation algorithms

Design of Nanoparticle-Based Carriers for Targeted Drug Delivery

Nanoparticles have shown promise as both drug delivery vehicles and direct antitumor systems, but they must be properly designed in order to maximize efficacy. Computational modeling is often used both to design new nanoparticles and to better understand existing ones. Modeled processes include the release of drugs at the tumor site and the physical interaction between the nanoparticle and cancer cells. In this paper, we provide an overview of three different targeted drug delivery methods (passive targeting, active targeting, and physical targeting) and compare methods of action, advantages, limitations, and the current stages of research. For the most commonly used nanoparticle carriers, fabrication methods are also reviewed. This is followed by a review of computational simulations and models on nanoparticle-based drug delivery