Energy frictional dissipating algorithm for rigid and ellastic body’s contact problems

An Energy Frictional Dissipating Algorithm (EFDA) for time integration of Coulomb frictional impact–contact problems is presented. Using the Penalty Method, and in the context of a conserving framework, linear and angular momenta are conserved and energy is consistently dissipated. Published formulations were stable, forcing the energy dissipation to be monotonic in order to prevent unstable energy growth. The shortcoming of many was that they were not able to reproduce the real kinematics and dissipation of physical processes, provided by analytical formulations and experiments. EFDA formulates a conserving framework based on a physical energy dissipation estimator. This framework uses an enhanced Penalty contact model based on a spring and a dashpot, enforcing physical frictional energy dissipation, controlling gap vibrations and modifying the velocities and contact forces during each time step. The result is that the dissipated energy, kinematics and contact forces are consistent with the expected physical behavior

Reliability-based dynamical design of a singular structure for use in High Energy Physics experiments

[EN] The present work presents a comprehensive design and dynamic calculation of singular metallic structures, part of the Neutrino Experiment NEXT. The experiment uses an electroluminescent TPC chamber, a high-pressure 136Xe gas vessel enclosing the detector. A lead-block "castle'' or containing box shields this vessel against external g-rays from all directions; in spite of its heavy weight, the castle must be regularly open for the detector maintenance. Since the structures will be constructed at a middle-level seismic localization (Laboratorio Subterraneo Canfranc, Spain), the earthquake hazard must be taken into account. Vessel and castle are supported by a rigid frame, which must satisfy two requirements: (i) the Spanish seismic standard, (ii) for equipment protection, the detector maximum horizontal acceleration must be < 1 [m/s(2)]. This frame rests on special base isolators to decrease horizontal accelerations in case of an earthquake. Three dynamical calculations are conducted: (i) a response spectrum analysis to comply with the standard, (ii) five time-history analyses to calculate tolerances and, (iii) a reliability-based approach using 1000 timehistory responses to ensure satisfaction of the operating requirements. The final outcome is the design of a singular structure optimized for the NEXT experiment with a probability of failure against any standard earthquake of only 0.125%. (C) 2017 Politechnika Wroclawska. Published by Elsevier Sp. z o.o. All rights reserved.This research was supported by the grants CSD2008-00037 Canfranc Underground Physics.Palma, R.; Torrent, J.; Pérez-Aparicio, JL.; Ripoll, L. (2018). Reliability-based dynamical design of a singular structure for use in High Energy Physics experiments. Archives of Civil and Mechanical Engineering. 18(1):256-266. https://doi.org/10.1016/j.acme.2017.07.00325626618

Optimization of pulsed thermoelectric materials using simulated annealing and non-linear finite elements

[EN] The objective of this work is to determine the optimal shape, gains and duration of an electric pulse applied to a Peltier cell, together with the length of the thermoelectric to maximize cooling while min- imizing electric consumption. For this purpose, a fully coupled, multiphysics, dynamic finite-element model, which solves for the thermal, electric and mechanical fields is used. Because of the demanding computing requirements of the optimization process, a special mesh is designed and a convergence anal- ysis is carried out before using the multiphysics model. The highly non-linear optimization is done by simulated annealing, a heuristic algorithm in the Markov chain Monte-Carlo family. A preliminary para- metric investigation is presented, analyzing the impact of some of the parameters. The results of this pre- liminary analysis help to understand the effect of the different shapes in the evolution of the cold face temperature. Some of these results are expected and have already been discussed elsewhere, but others can only be explained after further analysis and a full system modeling. Pulse optimization is multiobjec- tive and multiparametric, i.e., it can consider several targets such as maximizing the cooling temperature, the cooling duration or others. The trade-offs between the different targets are studied. In all cases, stres- ses inside the thermoelement are examined at all points, and the pulses must meet the restriction that an equivalent stress is not above the allowable value.This research was partially supported by the grants, Haut-de-France Region (CR Picardie, 120-2015-RDISTRUCT-000010), EU funding (FEDER, RDISTRUCT-000010) for Chaire-de-Mecanique, and Spanish Ministry of Economy and Competitiveness grant CGL2014-59841-P. These supports are gratefully acknowledgedMoreno-Navarro, P.; Pérez-Aparicio, JL.; Gómez-Hernández, JJ. (2017). Optimization of pulsed thermoelectric materials using simulated annealing and non-linear finite elements. Applied Thermal Engineering. 120:603-613. https://doi.org/10.1016/j.applthermaleng.2017.04.036S60361312

Analytical and multicoupled methods for optimal steady-state thermoelectric solutions

[EN] Peltier cells have low efficiency, but they are becoming attractive alternatives for affordable and environmentally clean cooling. In this line, the current article develops closed-form and semianalytical solutions to improve the temperature distribution of Bi2Te3 thermoelements. From the distribution, the main objective of the current work-the optimal electric intensity to maximize cooling-is inferred. The general one-dimensional differential coupled equation is integrated for linear and quadratic geometry of thermoelements, under temperature constant properties. For a general shape, a piece-wise solution based on heat flux continuity among virtual layers gives accurate analytical solutions. For variable properties, another piece-wise solution is developed but solved iteratively. Taking advantage of the formulae, the optimal intensity is directly derived with a minimal computational cost; its value will be of utility for more advanced designs. Finally, a parametric study including straight, two linear, barrel, hourglass and vase geometries is presented, drawing conclusions on how the shape of the thermoelement affects the coupled phenomena. A specially developed coupled and non-linear finite element research code is run taking into account all the materials of the cell and using symmetries and repetitions. These accurate results are used to validate the analytical ones.This work was supported by the Generalitat Valenciana research programmes PROMETEO/2020/016: Applications de Topologic Isolators in Spintronics and Thermoelectricity (TOP-TERM) and BEST/2021/079. The support is gratefully acknowledged.Moreno-Navarro, P.; Pérez-Aparicio, JL.; Gómez-Hernández, JJ. (2022). Analytical and multicoupled methods for optimal steady-state thermoelectric solutions. Coupled Systems Mechanics, an international journal. 11(2):151-166. https://doi.org/10.12989/csm.2022.11.2.15115116611

Fuzzy controller to compensate comunication loads in real-time

[EN] A Fuzzy Resource Manager (RM) to compensate communication loads in real-time systems is presented. The design is based on a new model of a Constant Bandwidth Server (CBS), which is responsible for assigning time slots to tasks with the highest priority when idle time is available. Assuming that each application can be executed at dierent service levels, without being below a minimum limit, a fuzzy approach is introduced that allows to adjust the time resources assigned to each task and to compensate non-linearities in time resources requests. The RM increases or decreases the virtual platform for each application and assigns a maximum process time budget for it, which is gradually used and refilled when depleted, without aecting the other applications. The scheme self-adjusts to sudden changes in applications process time requirements.[ES] Se presenta un administrador de recursos (RM) difuso para compensar las cargas de comunicación en sistemas en tiempo real. El diseño del RM se basa en un nuevo modelo de Servidor de Ancho de Banda Constante (CBS) que se encarga, a través de una plataforma virtual, de asignar tiempo de proceso a las tareas de mayor prioridad cuando existe capacidad disponible. Si se asume que cada aplicación puede ser ejecutada con diferentes niveles de servicio sin que este esté por debajo de un límite mínimo, se propone una aproximación difusa que permite actualizar de manera gradual los tiempos de proceso asignados a cada tarea. Esta aproximación permite compensar el comportamiento no lineal en las solicitudes de tiempo de proceso. El RM aumenta o disminuye la plataforma virtual para cada aplicación y le asigna un presupuesto máximo de tiempo de proceso, mismo que la aplicación usa gradualmente y que se reasigna al agotarse, sin por ello afectar el desempeño del resto de las aplicaciones. El esquema se auto-ajusta cuando ocurren a cambios repentinos en los requerimientos de tiempo de proceso de las aplicaciones.Este trabajo ha sido realizado parcialmente gracias al apoyo del CONACYT BECA 597175, PAPIIT IT100320 y PAPIIT IN104516.Aparicio-Santos, J.; Hermosillo-Gómez, J.; Benítez-Pérez, H.; Álvarez-Icaza, L. (2021). Controlador difuso para compensar cargas de comunicación en sistemas en tiempo real. Revista Iberoamericana de Automática e Informática industrial. 18(3):288-299. https://doi.org/10.4995/riai.2021.14544OJS288299183Abeni, L., Buttazzo, G., Dec 1998. Integrating multimedia applications in hard real-time systems. In: Proceedings 19th IEEE Real-Time Systems Symposium (Cat. No.98CB36279). pp. 4-13. https://doi.org/10.1109/REAL.1998.739726Aparicio, Santos, J. A., 2017. Diseño de un controlador difuso para compensar cargas de comunicación en tiempo real. Master's thesis, Universidad Nacional Autónoma de México, México.Bini, E., Buttazzo, G., Eker, J., Schorr, S., Guerra, R., Fohler, G., Arzen, K. E., Romero, V., Scordino, C., May 2011. Resource management on multicore systems: The actors approach. IEEE Micro 31 (3), 72-81. https://doi.org/10.1109/MM.2011.1Boutalis, Y., Theodoridis, D., Kottas, T., Christodoulou, M. A., 2014. System Identification and Adaptive Control: Theory and Applications of the Neurofuzzy and Fuzzy Cognitive Network Models. Springer.Buttazzo, G. C., 2011. Hard Real-Time Computing Systems: Predictable Scheduling Algorithms and Applications, 3rd Edition. Springer Publishing Company, Incorporated. Byeong Gi, L., Daeyoung, P., Hanbyul, S., 2009. Wireless Communications Resource Managemen. John Wiley and Sons.Byeong Gi, L., Daeyoung, P., Hanbyul, S., 2009. Wireless Communications Resource Managemen. John Wiley and Sons.Chasparis, G., Maggio, M., Arzen, K. E., Bini, E., June 2013. Distributed management of cpu resources for time-sensitive applications. In: 2013 American Control Conference. pp. 5305-5312. https://doi.org/10.1109/ACC.2013.6580666Chasparis, G. C., Maggio, M., Bini, E., Arzen, K.-E., 2016. Desing and implementation of distributed resource management for time-sensitive applications. Automatica 64, 44 - 53. https://doi.org/10.1016/j.automatica.2015.09.015Clark, R. K., 1990. Scheduling dependent real-time activities. Ph.D. thesis, USA, aAI9107552.Ganz, A., Ganz, Z., Wongthavarawat, K., 2003. Multimedia Wireless Networks: Technologies, Standards and QoS. Pearson Education.Horn, W., 1974. Some simple scheduling algorithms. Naval Research Logistics Quarterly 21 (1), 177-185. https://doi.org/10.1002/nav.3800210113IEEE Standard Glossary of Software Engineering Terminology. https://doi.org/10.1109/IEEESTD.1990.101064Litoiu, M., Tadei, R., 2001. Fuzzy scheduling with application to real-time systems. Fuzzy Sets and Systems 121 (3), 523 - 535. https://doi.org/10.1016/S0165-0114(99)00176-1Mahmoud, M., of Engineering, I., Technology, 2013. Distributed Control and Filtering for Industrial Systems. Control, Robotics and Sensors. Institution of Engineering and Technology. URL: https://books.google.com.mx/books?id=qWhWx2hRLYcC https://doi.org/10.1049/PBCE088EMok, A. K., Feng, X., May 2001. Resource partition for real-time systems. In: Proceedings Seventh IEEE Real-Time Technology and Applications Symposium. pp. 75-84. https://doi.org/10.1109/RTTAS.2001.929867Nesbit, K. J., Moreto, M., Cazorla, F. J., Ramirez, A., Valero, M., Smith, J. E., May 2008. Multicore resource management. IEEE Micro 28 (3), 6-16. https://doi.org/10.1109/MM.2008.43Quanser, 2012. USER MANUAL 3 DOF Gyroscope Experiment Set Up and Configuration. Quanser inc.Robert H. Cannon, J., 2003. Dynamics Of Physical Systems. Dover Publications, INC.Stankovic, J. A., 1988. Misconceptions about real-time computing: a serious problem for next-generation systems. Computer 21 (10), 10-19. https://doi.org/10.1109/2.7053Subrata, R., Zomaya, A. Y., Landfeldt, B., Oct 2008. A cooperative game framework for qos guided job allocation schemes in grids. IEEE Transactions on Computers 57 (10), 1413-1422. https://doi.org/10.1109/TC.2008.79Tanaka, K., Ikeda, T., Wang, H. O., May 1998. Fuzzy regulators and fuzzy observers: relaxed stability conditions and lmi-based designs. IEEE Transactions on Fuzzy Systems 6 (2), 250-265. https://doi.org/10.1109/91.66902

Optimal numerical design of bucket elevators using discontinuous deformation analysis

Bucket elevators are efficient machines to transport granular materials in industrial and civil engineering applications. These materials are composed of hundreds, thousands or even more particles, the global behavior of which is defined by contact interactions. The first attempts to analyze the transportation of granular materials were treated by very simple continuum methods that do not take into account these interactions, producing simulations that do not fit the experimental results accurately. Given the internal discontinuity nature of granular media, it is reasonable to use numerical methods to model their behavior, such as discontinuous deformation analysis (DDA)-a member of the discrete element method family that started to be used in the 90s to analyze similar problems. The version of DDA used in the current work treats grains as rigid circular particles with friction, damping and eventually cohesion with the objective of simulating and analyzing in detail the discharge of granular materials with bucket elevators. A deterministic computer code has been implemented and validated against simplified analytical formulae and experimental results taken from the literature. This computer code is then used to obtain optimum two-dimensional bucket geometries under specific working conditions. The optimization aims to maximize transport distance and to minimize remaining material, taking into account bucket velocity and the properties of the grains. The resulting geometries are discussed and compared against standard designs.J.L. Perez-Aparicio, R. Bravo were partially supported by the MFOM I+D (2004/38), both by MICIIN #BIA 2008-00522 and the first also by Polytechnic University of Valencia under grant PAID 05-10-2674. J.J. Gomez-Hernandez was partially supported by MICIIN #CGL 2011-23295.Pérez Aparicio, JL.; Bravo, R.; Gómez-Hernández, JJ. (2014). Optimal numerical design of bucket elevators using discontinuous deformation analysis. Granular Matter. 16(4):485-498. https://doi.org/10.1007/s10035-014-0485-5S485498164Rademacher, F.: Non-spill discharge characteristics of bucket elevators. Powder Technol. 22(2), 215–241 (1979)Koster, K.: Bulk material discharge of bucket elevators, especially high-capacity bucket elevators. [zum schuettgutabwurf bei becherwerken, insbesondere bei hochleistungsbecherwerken]. Aufbereitungs-Technik 25(8), 450–463 (1984)Koster, K.: Use of high-capacity bucket elevators in the cement industry. [zum einsatz von hochleistungsbecherwerken in der zementindustrie]. Zement-Kalk-Gips 33(3), 116–119 (1980)Koster, K.: Development and state of the art in heavy-duty bucket elevators with central chains—part 2 [entwicklung und stand der technik von hochleistungs-becherwerken mit zentralkette—teil 2]. ZKG Int. 49(4), 173–187 (1996)Koster, K.: Centrifugal discharge of bucket elevators. Bulk Solids Handl. 5(2), 449–460 (1985)Koster, K.: Problem of complete emptying of high-speed elevator buckets. Aufbereitungs-Technik 27(9), 471–481 (1986)Korzen, Z.: Mechanics of gravitational discharge of cell-less bucket wheels in reclaiming machines. Bulk Solids Handl. 7(6), 801–812 (1987)Korzen, Z., Dudek, K.: Mathematical model of the operational efficiency of a multibucket centrifugal discharge wheel [model matematyczny wydajnosci roboczego procesu kola wieloczerpakowego z odsrodkowym wysypem]. Politechnika Warszawska Prace Naukowe Mechanika 1(121), 187–199 (1989)Shi, G., Goodman, R.: Two dimensional discontinuous deformation analysis. Int. J. Numer. Anal. Methods Geomech. 9(6), 541–556 (1985)Pérez-Aparicio, J., Bravo, R.: Discrete Elements, vol. 2, pp. 41–77. Consorcio TCN (2006)Shi, G.: Discontinuous Deformation Analysis: A New Model for the Statics and Dynamics of Block Systems. Ph.D. thesis, University of California, Berkeley (1988)Moosavi, M., Grayeli, R.: A model for cable bolt-rock mass interaction: integration with discontinuous deformation analysis (DDA) algorithm. Int. J. Rock Mech. Min. Sci. 43(4), 661–670 (2006)Pérez-Aparicio, J., Bravo, R., Ortiz, P.: Refined element discontinuous numerical analysis of dry-contact masonry arches. Eng. Struct. 48, 578–587 (2013)McBride, W., Sinnott, M., Cleary, P.: Discrete element modelling of a bucket elevator head pulley transition zone. Granul. Matter 13(2), 169–174 (2011)Kruggel-Emden, H., Sudbrock, F., Wirtz, S., Scherer, V.: Experimental and numerical investigation of the bulk behavior of wood pellets on a model type grate. Granul. Matter 14(6), 681–693 (2012)Walton, O., Moor, C., Gill, K.: Effects of gravity on cohesive behavior of fine powders: implications for processing lunar regolith. Granul. Matter 9(5), 353–363 (2007)Gao, Y., Muzzio, F., Ierapetritou, M.: Optimizing continuous powder mixing processes using periodic section modeling. Chem. Eng. Sci. 80, 70–80 (2012)Shmulevich, I.: State of the art modeling of soil-tillage interaction using discrete element method. Soil Tillage Res. 111(1), 41–53 (2010)Moon, T., Oh, J.: A study of optimal rock-cutting conditions for hard rock tbm using the discrete element method. Rock Mech. Rock Eng. 45(5), 837–849 (2012)Makokha, A., Moys, M., Bwalya, M., Kimera, K.: A new approach to optimising the life and performance of worn liners in ball mills: experimental study and DEM simulation. Int. J. Miner. Process. 84(1–4), 221–227 (2007)Balevičius, R., Kačianauskas, R., Mroz, Z., Sielamowicz, I.: Discrete element method applied to multiobjective optimization of discharge flow parameters in hoppers. Struct. Multidiscip. Optim. 31(3), 163–175 (2006)Hu, L.: Gradual deformation and iterative calibration of Gaussian-related stochastic models. Math. Geol. 32(1), 87–108 (2000)Bravo, R., Pérez-Aparicio, J., Laursen, T.: An energy consistent frictional dissipating algorithm for particle contact problems. Int. J. Numer. Methods Eng. 92(9), 753–781 (2012)Belytschko, T., Liu, W., Moran, B.: Nonlinear Finite Elements for Continua and Structures. Wiley, New York (2000)Beckert, R., Föll, R.: Untersuchung der abwurfverhältnisse an kettenbecherwerken. Förden Heben 1(15), 833–836 (1966)Jaskulski, A.: Engineer-to-order approach to high speed bucket elevator design in a small-enterprise. Appl. Eng. Agric. 24(5), 545–557 (2008)Beverley, G.: Mechanics of High Speed Bucket Elevator Discharge. Ph.D. thesis. University of Newcastle (1986)Beverley, G., Roberts, A., Hayes, J.: Mechanics of high speed elevator discharge. Bulk Solids Handl. 3(4), 853–859 (1983)Korzen, Z., Dudek, K.: Reclaiming with a high-speed bucket wheel with centrifugal discharge. Bulk Solids Handl. 11(3), 615–626 (1991)Bravo, R., Pérez-Aparicio, J., Laursen, T.: An enhanced energy conserving time stepping algorithm for frictionless particle contacts. Int. J. Numer. Methods Eng. 85(11), 1415–1435 (2011)Jaskulski, A.: Methodology of Multi-Criteria Optimization of Appliances for Vertical Grain Transportation. Ph.D. thesis. Warsaw University of Technology (1992

Lyman break and UV-selected galaxies at z ~ 1: II. PACS-100um/160um FIR detections

We report the PACS-100um/160um detections of a sample of 42 GALEX-selected and FIR-detected Lyman break galaxies (LBGs) at z ~ 1 located in the COSMOS field and analyze their ultra-violet (UV) to far-infrared (FIR) properties. The detection of these LBGs in the FIR indicates that they have a dust content high enough so that its emission can be directly detected. According to a spectral energy distribution (SED) fitting with stellar population templates to their UV-to-near-IR observed photometry, PACS-detected LBGs tend to be bigger, more massive, dustier, redder in the UV continuum, and UV-brighter than PACS-undetected LBGs. PACS-detected LBGs at z ~ 1 are mostly disk-like galaxies and are located over the green-valley and red sequence of the color-magnitude diagram of galaxies at their redshift. By using their UV and IR emission, we find that PACS-detected LBGs tend to be less dusty and have slightly higher total star-formation rates (SFRs) than other PACS-detected UV-selected galaxies within their same redshift range. As a consequence of the selection effect due to the depth of the FIR observations employed, all our PACS-detected LBGs are LIRGs. However, none of them are in the ULIRG regime, where the FIR observations are complete. The finding of ULIRGs-LBGs at higher redshifts suggests an evolution of the FIR emission of LBGs with cosmic time. In an IRX-$\beta$ diagram, PACS-detected LBGs at z ~ 1 tend to be located around the relation for local starburst similarly to other UV-selected PACS-detected galaxies at their same redshift. Consequently, the dust-correction factors obtained with their UV continuum slope allow to determine their total SFR, unlike at higher redshifts. However, the dust attenuation derived from UV to NIR SED fitting overestimates the total SFR for most of our PACS-detected LBGs in age-dependent way: the overestimation factor is higher in younger galaxies.Comment: Accepted for publication in MNRA

Radon and material radiopurity assessment for the NEXT double beta decay experiment

The Neutrino Experiment with a Xenon TPC (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.Comment: Proceedings of the Low Radioactivity Techniques 2015 workshop (LRT2015), Seattle, March 201

The Spanish Pancreatic Club recommendations for the diagnosis and treatment of chronic pancreatitis: Part 1 (diagnosis)

Chronic pancreatitis (CP) is a relatively uncommon, complex and heterogeneous disease. The absence of a gold standard applicable to the initial phases of CP makes its early diagnosis difficult. Some of its complications, particularly chronic pain, can be difficult to manage. There is much variability in the diagnosis and treatment of CP and its complications amongst centers and professionals. The Spanish Pancreatic Club has developed a consensus on the management of CP. Two coordinators chose a multidisciplinary panel of 24 experts on this disease. A list of questions was drafted, and two experts reviewed each question. Then, a draft was produced and shared with the entire panel of experts and discussed in a face-to-fac