Selectively embedding multiple spatially steered fibers in polymer composite parts made using vat photopolymerization

Fiber-Reinforced Polymer Composite (FRPC) parts are mostly made as laminates, shells, or surfaces wound with 2D fiber patterns even after the emergence of additive manufacturing. Making FRPC parts with embedded continuous fibers in 3D is not reported previously even though topology optimization shows that such designs are optimal. Earlier attempts in 3D fiber reinforcement have demonstrated additively manufactured parts with channels into which fibers are inserted. In this paper, we present 3D printing techniques along with a printer developed for printing parts with continuous fibers that are spatially embedded inside the matrix using a variant of vat photopolymerization. Multiple continuous fibers are gradually steered as the part is built layer upon layer instead of placing them inside channels made in the part. We show examples of spatial fiber patterns and geometries built using the 3D printing techniques developed in this work. We also test the parts for strength and illustrate the importance of spatially embedding fibers in specific patterns.Comment: 9 pages and 8 figure

Stage-Discharge Prediction for Converging Compound Channels with Narrow Floodplains

Momentum transfer between a main channel and side floodplains tends to increase the floodplain shear and decrease the main channel shear. The increase and decrease in shear are greatly influenced when a compound channel has nonprismatic floodplains. In converging compound channels, water flow on the floodplain crosses over water flow in the main channel, resulting in increased interactions and momentum exchanges. An experimental analysis concerning the distribution of shear stress in the main channel and the floodplain for both prismatic and nonprismatic compound channels under different overbank flow conditions are performed. New equations are developed for predicting boundary shear stress distribution for a compound channel with the nonprismatic flood plain. Using these expressions the stage-discharge relationships for both prismatic and nonprismatic compound channels of lower width ratios are successfully estimated. The efficiency of the models is verified by applying natural river data sets

Sinuosity Dependency in Boundary Shear Distribution Modeling for Meandering Compound Channels

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Robot-aided selective embedding of a spatially steered fiber in polymer composite parts made using vat photopolymerization

Fiber-Reinforced Polymer Composite (FRPC) parts are predominantly laminates, shells, or surfaces wound with 2+D fiber patterns even after the emergence of additive manufacturing. Making FRPC parts with embedded continuous fibers in 3D is not reported previously even though topology optimization demonstrates that such designs are optimal. Earlier attempts in 3D fiber reinforcement include making parts with channels into which fibers are inserted or coextruding fiber with resin. In this work, A Vat-Photopolymerization Machine, and a process for concurrent embedding of spatially steered continuous fibers inside the matrix is developed. A single continuous fiber was embedded spatially using a robot to gradually steer the fiber as the part is built layer upon layer. An example of a fiber embedded along a helix in a cylindrical matrix is included in this work. Furthermore, a hinge effect was demonstrated when a fiber was embedded at a place that has substantial bending about the axis of the fiber.Mechanical Engineerin

Experimental signatures of quantum and topological states in frustrated magnetism

Frustration in magnetic materials arising from competing exchange interactions can prevent the system from adopting long-range magnetic order and can instead lead to a diverse range of novel quantum and topological states with exotic quasiparticle excitations. Here, we review prominent examples of such emergent phenomena, including magnetically-disordered and extensively degenerate spin ices, which feature emergent magnetic monopole excitations, highly-entangled quantum spin liquids with fractional spinon excitations, topological order and emergent gauge fields, as well as complex particle-like topological spin textures known as skyrmions. We provide an overview of recent advances in the search for magnetically-disordered candidate materials on the three-dimensional pyrochlore lattice and two-dimensional triangular, kagome and honeycomb lattices, the latter with bond-dependent Kitaev interactions, and on lattices supporting topological magnetism. We highlight experimental signatures of these often elusive phenomena and single out the most suitable experimental techniques that can be used to detect them. Our review also aims at providing a comprehensive guide for designing and investigating novel frustrated magnetic materials, with the potential of addressing some important open questions in contemporary condensed matter physics

Numerical modeling of converging compound channel flow

This paper presents numerical analysis for prediction of depth-averaged velocity distribution of compound channels with converging flood plains. Firstly, a 3D Computational Fluid Dynamics model is used to establish the basic database under various working conditions. Numerical simulation in two phases is performed using the ANSYS-Fluent software. k-ω turbulence model is executed to solve the basic governing equations. The results have been compared with high-quality flume measurements obtained from different converging compound channels in order to investigate the numerical accuracy. Then Artificial Neural Network are trained based on the Back Propagation Neural Network technique for depth-averaged velocity prediction in different converging sections and these test results are compared with each other and with actual data. The study has focused on the ability of the software to correctly predict the complex flow phenomena that occur in channel flows

Modified Weber Ferguson incision - A rare traumatic serendipity

Aim: Road traffic accident has become a menace in today’s expanding era. The traumatic injury caused due to such accidents hampers the normal life of the patients. These injuries are very dangerous and may even possess threat to life. These injuries often result in deep lacerations with tissue loss giving rise to ugly scar and even marked facial disfigurement. Surgical esthetic primary closure of soft tissue laceration is a challenge for oral and maxillofacial surgeon. The aim of this commentary is to present a case report of a 19-year-old female patient with lacerated wound in the midface region which had a coincidental resemblance to a modified Weber Ferguson incision. Conclusion: An uncommon resemblance of a traumatic laceration with well-known Weber Ferguson incision and its management has been discussed in this report. Clinical Significance: Clinical alikeness of such incision is a rare entity, and the importance of early esthetic primary closure of this ugly injury is an important treatment aspect for the maxillofacial surgeons

Dynamics of Logamediate and Intermediate Scenarios in the Dark Energy Filled Universe

We have considered a model of two component mixture i.e., mixture of Chaplygin gas and barotropic fluid with tachyonic field. In the case, when they have no interaction then both of them retain their own properties. Let us consider an energy flow between barotropic and tachyonic fluids. In both the cases we find the exact solutions for the tachyonic field and the tachyonic potential and show that the tachyonic potential follows the asymptotic behavior. We have considered an interaction between these two fluids by introducing a coupling term. Finally, we have considered a model of three component mixture i.e., mixture of tachyonic field, Chaplygin gas and barotropic fluid with or without interaction. The coupling functions decays with time indicating a strong energy flow at the initial period and weak stable interaction at later stage. To keep the observational support of recent acceleration we have considered two particular forms (i) Logamediate Scenario and (ii) Intermediate Scenario, of evolution of the Universe. We have examined the natures of the recent developed statefinder parameters and slow-roll parameters in both scenarios with and without interactions in whole evolution of the universe.Comment: 28 pages, 20 figure