Forecasting coal resources and reserves in heterogeneous coal zones using 3D facies models (As Pontes Basin, NW Spain)

Forecasting coal resources and reserves is critical for coal mine development. Thickness maps are commonly used for assessing coal resources and reserves; however they are limited for capturing coal splitting effects in thick and heterogeneous coal zones. As an alternative, three-dimensional geostatistical methods are used to populate facies distributionwithin a densely drilled heterogeneous coal zone in the As Pontes Basin (NWSpain). Coal distribution in this zone is mainly characterized by coal-dominated areas in the central parts of the basin interfingering with terrigenous-dominated alluvial fan zones at the margins. The three-dimensional models obtained are applied to forecast coal resources and reserves. Predictions using subsets of the entire dataset are also generated to understand the performance of methods under limited data constraints. Three-dimensional facies interpolation methods tend to overestimate coal resources and reserves due to interpolation smoothing. Facies simulation methods yield similar resource predictions than conventional thickness map approximations. Reserves predicted by facies simulation methods are mainly influenced by: a) the specific coal proportion threshold used to determine if a block can be recovered or not, and b) the capability of the modelling strategy to reproduce areal trends in coal proportions and splitting between coal-dominated and terrigenousdominated areas of the basin. Reserves predictions differ between the simulation methods, even with dense conditioning datasets. Simulation methods can be ranked according to the correlation of their outputs with predictions from the directly interpolated coal proportion maps: a) with low-density datasets sequential indicator simulation with trends yields the best correlation, b) with high-density datasets sequential indicator simulation with post-processing yields the best correlation, because the areal trends are provided implicitly by the dense conditioning data.

Mass transfer and particleinteractions in granular systems and suspension flows

The purpose of this study was to investigate some important features of granular flows and suspension flows by computational simulation methods. Granular materials have been considered as an independent state ofmatter because of their complex behaviors. They sometimes behave like a solid, sometimes like a fluid, and sometimes can contain both phases in equilibrium. The computer simulation of dense shear granular flows of monodisperse, spherical particles shows that the collisional model of contacts yields the coexistence of solid and fluid phases while the frictional model represents a uniform flow of fluid phase. However, a comparison between the stress signals from the simulations and experiments revealed that the collisional model would result a proper match with the experimental evidences. Although the effect of gravity is found to beimportant in sedimentation of solid part, the stick-slip behavior associated with the collisional model looks more similar to that of experiments. The mathematical formulations based on the kinetic theory have been derived for the moderatesolid volume fractions with the assumption of the homogeneity of flow. In orderto make some simulations which can provide such an ideal flow, the simulation of unbounded granular shear flows was performed. Therefore, the homogeneous flow properties could be achieved in the moderate solid volume fractions. A new algorithm, namely the nonequilibrium approach was introduced to show the features of self-diffusion in the granular flows. Using this algorithm a one way flow can beextracted from the entire flow, which not only provides a straightforward calculation of self-diffusion coefficient but also can qualitatively determine the deviation of self-diffusion from the linear law at some regions nearby the wall inbounded flows. Anyhow, the average lateral self-diffusion coefficient, which was calculated by the aforementioned method, showed a desirable agreement with thepredictions of kinetic theory formulation. In the continuation of computer simulation of shear granular flows, some numerical and theoretical investigations were carried out on mass transfer and particle interactions in particulate flows. In this context, the boundary element method and its combination with the spectral method using the special capabilities of wavelets have been introduced as theefficient numerical methods to solve the governing equations of mass transfer in particulate flows. A theoretical formulation of fluid dispersivity in suspension flows revealed that the fluid dispersivity depends upon the fluid properties and particle parameters as well as the fluid-particle and particle-particle interactions.

The Impact of a Character Posture Model on the Communication of Affect in an Immersive Virtual Environment

This paper presents the quantitative and qualitative findings from an experiment designed to evaluate a developing model of affective postures for full-body virtual characters in immersive virtual environments (IVEs). Forty-nine participants were each requested to explore a virtual environment by asking two virtual characters for instructions. The participants used a CAVE-like system to explore the environment. Participant responses and their impression of the virtual characters were evaluated through a wide variety of both quantitative and qualitative methods. Combining a controlled experimental approach with various data-collection methods provided a number of advantages such as providing a reason to the quantitative results. The quantitative results indicate that posture plays an important role in the communication of affect by virtual characters. The qualitative findings indicated that participants attribute a variety of psychological states to the behavioral cues displayed by virtual characters. In addition, participants tended to interpret the social context portrayed by the virtual characters in a holistic manner. This suggests that one aspect of the virtual scene colors the perception of the whole social context portrayed by the virtual characters. We conclude by discussing the importance of designing holistically congruent virtual characters especially in immersive settings.

Las reglas de la mayoría y Borda: un ejercicio de simulación

En el presente documento se describe un ejercicio de simulación orientado a facilitar la comprensión y asimilación del funcionamiento de la votación por mayoría y la regla de Borda. El ejercicio consiste en proponer a los alumnos que escojan entre dos proyectos (un programa de becas y una ampliación de las aulas de estudio) que presuntamente se van a realizar en la facultad en la que estudian. Para determinar qué proyecto se debería llevar a cabo se utiliza las reglas de la mayoría y Borda. Los alumnos deben responder a diversas rondas de votaciones donde el orden de la votación o agenda ha sido determinada por el instructor. El ejercicio es útil para exponer y debatir las cuestiones que se explican en un curso estándar de Hacienda Pública sobre el uso de la regla de la mayoría y la regla de Borda, como por ejemplo, la existencia de ciclos en los resultados de una votación, la posibilidad de condicionar el resultado de las votaciones mediante la manipulación de la agenda, el comportamiento estratégico, la formación de coaliciones, las propiedades del teorema de Arrow y la eficiencia de la(s) diferentes alternativas escogidas. El ejercicio se enmarca como parte de las actividades realizadas por el Grupo de Innovación Docente (GID-HAL) de la Universidad de Barcelona.

Emergent patterns of social organization in captive Cercocebus torquatus: Testing the GrooFiWorld agent-based model

We empirically applied the GrooFiWorld agent-based model (Puga-González et al. 2009) in a group of captive mangabeys (Cercocebus torquatus). We analysed several measurements related to aggression and affiliative patterns. The group adopted a combination of despotic and egalitarian behaviours resulting from the behavioural flexibility observed in the Cercopithecinae subfamily. Our study also demonstrates that the GrooFiWorld agent-based model can be extended to other members of the Cercopithecinae subfamily generating parsimonious hypotheses related to the social organization.

Anàlisi mitjançant mecànica de fluids computacional d’un aerogenerador minieòlic

A la UdGhi ha 2 aerogeneradors minieòlics: el del terrat del P2 i un de més petit allaboratori d’energies. Aquest segon aerogenerador minieòlic és el que s’ha utilitzat en aquestprojecte. Es tracta d’un Air-X de la casa Technosun amb les següents característiques:- Té un pes de 6Kg, un radi de 0,582 metres, un TSR de 8,8 i unapotència de 545W.- Perfil de la pala tipus SD2030.- Velocitat d’engegada de 3m/s.-Amb vents forts (més de 15m/s) un dispositiu electrònic redueix lavelocitat fins a 600rpm, reduint les càrregues sobre la turbina i l’estructuramentre encara segueix produint energia.- Baix manteniment. Només consta de dues parts mòbils.L’objecte que s’ha plantejat per aquest projecte ha estat trobar la corbade potència del minigenerador Air-X mitjançant simulació amb CFD, iutilitzant només les dades geomètriques de l’aparell

Efectos Visuales de las Aceleraciones Positivas Simulados por Ordenador

El artículo describe la simulación por ordenador digital de los efectos visuales en el organismo humano sometido a aceleraciones prositivas en sentido craneocaudal. Los resultados obtenidos posibilitan la utilización de un método complementario para la evaluación de la tolerancia a las aceleraciones positivas.

Precursor nanoscale modulations in ferromagnets: Modeling and thermodynamic characterization

Using a Ginzburg-Landau model for the magnetic degrees of freedom with coupling to disorder, we demonstrate through simulations the existence of stripelike magnetic precursors recently observed in Co-Ni-Al alloys above the Curie temperature. We characterize these magnetic modulations by means of the temperature dependence of local magnetization distribution, magnetized volume fraction, and magnetic susceptibility. We also obtain a temperature-disorder strength phase diagram in which a magnetic tweed phase exists in a small region between the paramagnetic and dipolar phases.

Cohesive Elements for Shells

A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design

Una pràctica de simulació de cas: la resolució de problemes i el procés diagnòstic

En aquest article presentem una experiència docent dins de l’àmbit de la Psicologia del Pensament. Es tracta d’una activitat d’aprenentatge basat en problemes en la qual els estudiants han de reflexionar sobre com determinats continguts de l’assignatura, els de resolució de problemes, estan fortament relacionats amb la seva futura pràctica professional i amb el desenvolupament del seu aprenentatge des de psicòlegs novells a psicòlegs experts. En este artículo presentamos una experiencia docente en el ámbito de la Psicología del Pensamiento. Se trata de una actividad de aprendizaje basado en problemas en la que los estudiantes han de reflexionar sobre cómo determinados contenidos de la asignatura, los de resolución de problemas, estan fuertemente relacionados con su futura práctica profesional y con el desarrollo de su aprendizaje desde psicólogos novatos a psicólogos expertos

Modeling of residual stresses and distortion due to welding in fillet welds

Welding has a growing role in modern world manufacturing. Welding joints are extensively used from pipes to aerospace industries. Prediction of welding residual stresses and distortions is necessary for accurate evaluation of fillet welds in relation to design and safety conditions. Residual stresses may be beneficial or detrimental, depending whether they are tensile or compressive and the loading. They directly affect the fatigue life of the weld by impacting crack growth rate. Beside theoretical background of residual stresses this study calculates residual stresses and deformations due to localized heating by welding process and subsequent rapid cooling in fillet welds. Validated methods are required for this purpose due to complexity of process, localized heating, temperature dependence of material properties and heat source. In this research both empirical and simulation methods were used for the analysis of welded joints. Finite element simulation has become a popular tool of prediction of welding residual stresses and distortion. Three different cases with and without preload have been modeled during this study. Thermal heat load set is used by calculating heat flux from the given heat input energy. First the linear and then nonlinear material behavior model is modeled for calculation of residual stresses. Experimental work is done to calculate the stresses empirically. The results from both the methods are compared to check their reliability. Residual stresses can have a significant effect on fatigue performance of the welded joints made of high strength steel. Both initial residual stress state and subsequent residual stress relaxation need to be considered for accurate description of fatigue behavior. Tensile residual stresses are detrimental and will reduce the fatigue life and compressive residual stresses will increase it. The residual stresses follow the yield strength of base or filler material and the components made of high strength steel are typically thin, where the role of distortion is emphasizing.

Virtual Testing of Active Magnetic Bearing Systems based on Design Guidelines given by the Standards

Active Magnetic Bearings offer many advantages that have brought new applications to the industry. However, similarly to all new technology, active magnetic bearings also have downsides and one of those is the low standardization level. This thesis is studying mainly the ISO 14839 standard and more specifically the system verification methods. These verifying methods are conducted using a practical test with an existing active magnetic bearing system. The system is simulated with Matlab using rotor-bearing dynamics toolbox, but this study does not include the exact simulation code or a direct algebra calculation. However, this study provides the proof that standardized simulation methods can be applied in practical problems.

Sähkökoneessa esiintyvien voimien yksityiskohtainen mittausjärjestelmä

Hissiteollisuudessa nostokoneistoina käytettyjen sähkömoottoreiden laatuvaatimukset ovat tiuken-tuneet viime vuosina. Erityisesti koneistojen tuottama ääni ja mekaaninen värähtely ovat olleet jat-kuvasti tiukentuneen tarkastelun alaisena. Hissikoriin ja hissiä ympäröiviin rakenteisiin välittyvästä värähtelystä johtuva ääni on yksi hissin laatuvaikutelmaan merkittävimmin vaikuttavia tekijöitä. Nostokoneisto on yksi tärkeimmistä äänen ja värähtelyn lähteistä hissijärjestelmässä. Koneiston suunnittelulla edellä mainittuja tekijöitä voidaan minimoida. Sähkökoneiden suunnittelussa finiit-tielementtimenetelmien (FEM) käyttö on vakiintunut haastavimmissa sovelluksissa. Kone Oyj:llä nostokoneistoina käytetään aksiaalivuokestomagneettitahtikoneita (AFPMSM), joiden FEM simu-lointiin käytetään yleisesti kolmea eri tapaa. Kukin näistä vaihtoehdoista pitää sisällään omat hyö-tynsä, että haittansa. Suunnittelun kannalta tärkeää on oikean menetelmän valinta ai-ka/informatiivisuus suhteen maksimoimiseksi. Erittäin tärkeää on myös saatujen tulosten oikeelli-suus. Tämän diplomityön tavoite on kehittää järjestelmä, jonka avulla AFPMS-koneen voimia voidaan mitata yksityiskohtaisella tasolla. Järjestelmän avulla voidaan tarkastella käytössä olevien FE-menetelmien tulosten oikeellisuutta sekä äänen että värähtelyn syntymekanismeja. Järjestelmän tarkoitus on myös syventää Kone Oyj tietotaitoa AFPMS-koneiden toiminnasta. Tässä työssä esitellään AFPMS-koneen epäideaalisuuksia, jotka voivat vaikuttaa mittajärjestelmän suunnitteluun. Myös koneen epäideaalisuuksiin lukeutuvaa ääntä on tarkasteltu tässä työssä. Jotta työn tavoitteiden mukaista FE-menetelmien vertailua ja tulosten oikeellisuuden tarkastelua voitai-siin tehdä, myös yleisimpiä AFPMS-koneen FE-menetelmiä tarkastellaan. Työn tuloksena on mittajärjestelmän suunnitelma, jonka avulla voidaan toteuttaa kuuden vapausas-teen voimamittaus jokaiselle koneistomagneetille alle 1N resoluutiolla. Suunnitellun järjestelmän toimivuutta on tarkasteltu FE-menetelmiä käyttäen ja järjestelmässä käytettävän voima-anturin ky-vykkyyttä on todennettu referenssimittauksin. Suunniteltu mittajärjestelmä mahdollistaa sähkömoottorin useiden eri epäideaalisuuksien tarkaste-lun yksityiskohtaisella tasolla. Mittausajatuksen soveltaminen myös muiden koneiden tutkimiseen tarjoaa mahdollisuuksia jatkotutkimuksille.

Modelling of changes in electricity end-use and their impacts on electricity distribution

The electricity distribution sector will face significant changes in the future. Increasing reliability demands will call for major network investments. At the same time, electricity end-use is undergoing profound changes. The changes include future energy technologies and other advances in the field. New technologies such as microgeneration and electric vehicles will have different kinds of impacts on electricity distribution network loads. In addition, smart metering provides more accurate electricity consumption data and opportunities to develop sophisticated load modelling and forecasting approaches. Thus, there are both demands and opportunities to develop a new type of long-term forecasting methodology for electricity distribution. The work concentrates on the technical and economic perspectives of electricity distribution. The doctoral dissertation proposes a methodology to forecast electricity consumption in the distribution networks. The forecasting process consists of a spatial analysis, clustering, end-use modelling, scenarios and simulation methods, and the load forecasts are based on the application of automatic meter reading (AMR) data. The developed long-term forecasting process produces power-based load forecasts. By applying these results, it is possible to forecast the impacts of changes on electrical energy in the network, and further, on the distribution system operator’s revenue. These results are applicable to distribution network and business planning. This doctoral dissertation includes a case study, which tests the forecasting process in practice. For the case study, the most prominent future energy technologies are chosen, and their impacts on the electrical energy and power on the network are analysed. The most relevant topics related to changes in the operating environment, namely energy efficiency, microgeneration, electric vehicles, energy storages and demand response, are discussed in more detail. The study shows that changes in electricity end-use may have radical impacts both on electrical energy and power in the distribution networks and on the distribution revenue. These changes will probably pose challenges for distribution system operators. The study suggests solutions for the distribution system operators on how they can prepare for the changing conditions. It is concluded that a new type of load forecasting methodology is needed, because the previous methods are no longer able to produce adequate forecasts.

Exact Tests for Contemporaneous Correlation of Disturbances in Seemingly Unrelated Regressions.

This paper proposes finite-sample procedures for testing the SURE specification in multi-equation regression models, i.e. whether the disturbances in different equations are contemporaneously uncorrelated or not. We apply the technique of Monte Carlo (MC) tests [Dwass (1957), Barnard (1963)] to obtain exact tests based on standard LR and LM zero correlation tests. We also suggest a MC quasi-LR (QLR) test based on feasible generalized least squares (FGLS). We show that the latter statistics are pivotal under the null, which provides the justification for applying MC tests. Furthermore, we extend the exact independence test proposed by Harvey and Phillips (1982) to the multi-equation framework. Specifically, we introduce several induced tests based on a set of simultaneous Harvey/Phillips-type tests and suggest a simulation-based solution to the associated combination problem. The properties of the proposed tests are studied in a Monte Carlo experiment which shows that standard asymptotic tests exhibit important size distortions, while MC tests achieve complete size control and display good power. Moreover, MC-QLR tests performed best in terms of power, a result of interest from the point of view of simulation-based tests. The power of the MC induced tests improves appreciably in comparison to standard Bonferroni tests and, in certain cases, outperforms the likelihood-based MC tests. The tests are applied to data used by Fischer (1993) to analyze the macroeconomic determinants of growth.