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]. 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Fine control of chlorophyll-carotenoid interactions defines the functionality of light-harvesting proteins in plants

V.B. and C.D.P.D. acknowledge the support from the Leverhulme Trust RPG-2015-337. This research utilized Queen Mary’s MidPlus computational facilities, supported by QMUL Research-IT and funded by EPSRC grant EP/K000128/1. W.P.B acknowledges support from the Photosynthetic Antenna Research Center (PARC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-SC0001035 for initial development of the TDC calculation code, as well as support from Army Research Office (ARO-MURI) Award W911NF1210420 for further development

Numerical Magneto-Mechanical Analysis of Destructive Coils with Reinforcement Cylinders of Various Thicknesses

The destructive laboratory device, generating half-period sinus-shaped magnetic field pulses of 0.15-2 ms duration is investigated numerically. The coil was placed into a steel reinforcement cylinder to resist magnetic forces, while influence of thickness of the reinforcement cylinder is considered in detail. The time-dependent non-linear magneto-mechanical model and the finite element software ANSYS are employed. On the basis of the mechanical analysis, reasonable explanation of the destruction nature is provided. The numerically obtained operation threshold value was in good agreement with experimental measurements

Arylmethylene-1,3-indandione based molecular glasses: Third order optical non-linearity

The synthesis and new optical features of three indan-1,3-dione class structures is reported. The simple arylmethylene-1,3-indandione structure 2-(4-diethylaminobenzylidene)indan-1,3-dione was used to design two linked structures: 1,3-bis-{3-hydroxy-4-[4-diethylamino-1-(1,3-dioxoindan-2- ylmethylene)benzen-3-yloxy]-1-thiabuthyl}benzene and 4,4′-bis-{{3-hydroxy- 4-[4-diethylamino-1-(1,3-dioxoindan-2-ylmethylene)benzen-3-yloxy]-1-thiabutyl} phenyl}sulfide. In contrast to the simple compound, which readily crystallized, the linked derivatives remained in an amorphous phase and are considered as molecular glasses with respective glass transition temperatures 88 and 100°C. For non-linear optical investigations samples were prepared as a guest-host system in polycarbonate matrix (10%). The Maker-fringe technique was used to investigate the third harmonic generation at a wavelength of 355 nm (YAG laser). Third-order non-linear susceptibility χ (3) values were extracted 5.75·10 -21 m 2 V -2, 8.60·10 -21 m 2 V -2, 16.85·10 -21 m 2 V -2 for these respective indandiones while modeling the experimental results. To evaluate the susceptibility of the indan-1,3-dione derivatives third harmonic generation a comparative experiment for a reference azodye in polycarbonate was performed. The results show an important feature - higher molecular second order hyperpolarizability for the linked structures. NMR, MS, IR, UV-VIS, XRD and elemental analysis were used to structurally characterize the new compounds and ellipsometry was applied to interpret the non-linear optical results. © 2012 Elsevier Ltd. All rights reserved