Mathematical Modeling of the Parabolic Trough Collector Field of the TCP-100 Research Plant

The 9th EUROSIM Congress on Modelling and Simulation, EUROSIM 2016 Oulu (Finlandia)There are two main drawbacks when operating solar energy systems: a) the resulting energy costs are not yet competitive and b) solar energy is not always available when needed. In order to improve the overall solar plants efficiency, advances control techniques play an important role. In order to develop efficient and robust control techniques, the use of accurate mathematical models is crucial. In this paper, the mathematical modeling of the new TCP100 parabolic trough collector (PTC) research facility at the Plataforma Solar de Almería is presented. Some simulations are shown to demonstrate the adequate behavior of the model compared to the facility design conditions.Junta de Andalucía P11-TEP-8129Unión Europea FP7-ICT-ICT-2013.3.4-611281Ministerio de Economía y Competitividadt DPI2014-56364-C2-2-

Three-dimensional finite-element analysis of osseointegrated dental implants

In this paper the biomechanical interaction between osseointegrated dental implants and bone is investigated by numerical simulations. The influence of some mechanical and geometrical parameters on bone stress distributions is highlighted and some risk-measures relevant to critical overloading are furnished. Load transfer mechanisms of several dental implants are analyzed by means of linearly elastic finite-element analyses, when static functional loads occur. For a given implant the variation of its performance with the placement is investigated, considering insertions both in mandibular and maxillary molar segments. The mechanical properties of the bone regions (cortical and cancellous) are approximated with those of a type II bone and the geometry of crestal bone loss after an healing period is modelled. Five commercially-available dental implants are analyzed, demonstrating as the optimal choice of an endosseous implant is strongly affected by a number of shape parameters as well as by anatomy and mechanical properties of the site of placement. Numerical results clearly proof as a given implant device exhibits very different performance on mandibular or maxillary bone segments, resulting in higher compressive stresses when maxillary placement is experienced. Finally, the effectiveness of several multiple-implant restorative applications is investigated. The first one is related to a partially edentulous arch restoration, based on a double-implant device involving a retaining bar. Other applications regard single-tooth restorations based on non-conventional devices consisting in a mini-bar supported by two mini endosteal implants, possibly reproducing the natural roots orientation of a multiple-root tooth

Les villes comme agents : simulation des futurs possibles du système urbain européen

L’approche systémique pour modéliser la dynamique des systèmes de villes est ancienne. Le concept d’auto-organisation et le formalisme des équations différentielles ont donné lieu à de nombreuses applications dans les années 1980. La simulation agent ouvre de nouvelles perspectives dans ce champ. L’objectif de cet article est d’abord de discuter des registres et du niveau d’explication qui sont mobilisés pour rendre compte des différentiels de croissance des villes. Il s’agit ensuite de montrer l’intérêt d’une approche agent pour formaliser des hypothèses au niveau méso-géographique des villes. Après un bref état de l’art sur le concept de systèmes de villes et les modèles spatio-temporels associés, le modèle EuroSim formalisé avec un système multi-agents est présenté. Celui-ci permet de simuler l’évolution des villes européennes entre 1950 et 2050 en testant différents scénarios relatifs à l’ouverture des frontières vers l’immigration non européenne et à l’existence ou non de barrières économiques internes.The systemic approach has long since been used for modelling the dynamics of systems of cities. Self-organization principles and differential equations have been broadly applied in the 1980’s. Agent-based models open new ways for simulating cities’ evolution. This paper discusses different registers and levels of explanation when it comes to cities’ growth rates differences. It also shows the interest of the agent approach for formalizing hypotheses at the meso-geographical level of cities. A short state of the art on the concept of system of cities and on the associated spatio-temporal models is given. The EuroSim model, developed with a multi-agent system, is presented. The evolution of European cities is simulated between 1950 and 2050 giving different scenarios on the opening of European borders to outside immigration and on the existence of internal economical barriers

Simulation and Impact of different Optimization Parameters on CO2 Capture Cost

The influence of different process parameters/factors on CO2 capture cost, in a standard amine based CO2 capture process was studied through process simulation and cost estimation. The most influential factor was found to be the CO2 capture efficiency. This led to investigation of routes for capturing more than 85% of CO2. The routes are by merely increasing the solvent flow or by increasing the absorber packing height. The cost-efficient route was found to be by increasing the packing height of the absorber. This resulted in 20% less cost compared to capturing 90% CO2 by increasing only the solvent flow. The cost optimum absorber packing height was 12 m (12 stages). The cost optimum temperature difference in the lean/rich heat exchanger was 5 °C. A case with a combination of the two cost optimum parameters achieved a 4% decrease in capture cost compared to the base case. The results highlight the significance of performing cost optimization of CO2 capture processes.publishedVersio

Simulation-based Cost Optimization tool for CO2 Absorption Processes: Iterative Detailed Factor (IDF) Scheme

A simple, fast, and accurate process simulation based cost estimation and optimization scheme was developed in Aspen HYSYS based on a detailed factorial methodology for solvent-based CO2 absorption and desorption processes. This was implemented with the aid of the spreadsheet function in the software. The aim is to drastically reduce the time to obtain cost estimates in subsequent iterations of simulation due to parametric changes, studying new solvents/blends and process modifications. All equipment costs in a reference case are obtained from Aspen In-Plant Cost Estimator V12. The equipment cost for subsequent iterations are evaluated based on cost exponents. Equipment that are not affected by any change in the process are assigned a cost exponent of 1.0 and the others 0.65, except the absorber packing height which is 1.1. The capital cost obtained for new calculations with the Iterative Detailed Factor (IDF) model are in good agreement with all the reference cases. The IDF tool was able to accurately estimate the cost optimum minimum approach temperature based on CO2 capture cost, with an error of less than 0.2%.publishedVersio

SIMULATION TOOLS AND SERVICES FOR MOBILE USERS: HISTORY, STATE-OF-THE-ART AND FUTURE

One of main ideas of this paper is a hypothesis that the simulation play an essentially more significant role in a human history and culture than it is usually assumed. On some examples it can be demonstrated that modern computational simulation has ancient prototypes and some artefacts can be interpreted as special simulation tools and environments. As typical examples of ancient simulation tools the “life/world tree” on mammoth bone and megalithical “models of the world” are presented. These artefacts were interpreted earlier as calendars, observatories or “ancient computers”. The proposed hypothesis considers the following interpretation as most exact and appropriate: “special computational simulation tools and environments with real-time functions (calendar) and real-world interface (observatory)”