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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 63 for “"FFF"”.
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In-Situ Monitoring and Simulations of the Non-Isothermal Crystallization of FFF Printed Materials
… of new materials for Fused Filament Fabrication (FFF). We demonstrate a novel FFF nozzle design to enable the first measurements of in-situ rheology inside FFF nozzles, which is critical for part performance by ensuring that the polymer extrudate is flowing at an appropriate temperature and flow …
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Comparison of Two Separation Methods for Biological Particles: Field-Flow Fractionation (FFF) and Sucrose Density Gradients
… centrifugation and Field-flow fractionation (FFF) are two different particle separation methods that overcome the problems of similar size microorganisms clumping together during standard filtration methods. FFF separates particles based on size and density via the parabolic velocity profile …
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Generation of Thermotropic Liquid Crystalline Polymer (TLCP)-Thermoplastic Composite Filaments and Their Processing in Fused Filament Fabrication (FFF)
… major limitations in Fused Filament Fabrication (FFF), a form of additive manufacturing, is the lack of composites with superior mechanical properties. Traditionally, carbon and glass fibers are widely used to improve the physical properties of polymeric matrices. However, the blending methods …
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High throughput extrusion additive manufacturing – rate limits and system design
Fused filament fabrication (FFF) is an additive manufacturing (AM) process in which a polymer feedstock is melted and extruded through a nozzle while guided by a motion system, resulting in a three-dimensional part. FFF is applicable across a range of length scales and with a wide variety of …
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Systematic assessment of the influence of voids on the material performance and failure in additively manufactured polymers.
Fused filament fabrication (FFF) is increasingly used for small-scale manufacturing for niche applications, however, its wide adoption for industrial-scale production of structural components requires significant improvement in the overall quality and functionality of the produced products. While …
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Creation of controlled polymer extrusion prediction methods in fused filament fabrication. An empirical model is presented for the prediction of geometric characteristics of polymer fused filament fabrication manufactured components
… of manufacturing Fused Filament Fabrication (FFF) components by calculating required process parameters using empirical equations. Such an empirical model has been required within the FFF field of research for a considerable amount of time and will allow for an expansion in understanding of …
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Improved Target Coverage of Spinal Metastases Through The Use of Flattening Filter Free Beams
… recurrence at follow-up. Flattening Filter Free (FFF) photon beams have been shown to have lower out-of-field dose and sharper dose gradients when compared with conventionally flattened (FF) photon beams of similar energy; this sharp dose fall-off could potentially prove beneficial in cases where …
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Development of A New Independent Monte Carlo Dose Calculation Quality Assurance Audit to ol For Clinical Trials
… 10MV and Varian TrueBeam Flattening Filter Free (FFF) 6MV and FFF 10MV therapeutic x-ray beams were developed. The Monte Carlo technique, using the Dose Planning Method (DPM) algorithm, was used in radiation dose calculations. During validation calculations were compared to open field measurements …
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Modelling material behavior for additively manufactured metals and polymers produced by fused filament fabrication
… and medical sectors. Fused Filament Fabrication (FFF) stands out as a prominent AM technique that builds the product layer by layer. Metal Fused Filament Fabrication (MFFF) employs a filament composed of metal powder and a polymer binder. The MFFF process involves three key stages: printing, …
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Process and Material Modifications to Enable New Material for Material Extrusion Additive Manufacturing
… library for the fused filament fabrication (FFF) material extrusion additive manufacturing (AM) process through innovations in the FFF process, post-process, and polymer composition. This research was conducted at two opposing ends of the FFF-processing temperature: low processing temperature …
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Additive Manufacturing in Spacecraft Design and In-Space Robotic Fabrication of Large Structures
… used process being Fused Filament Fabrication (FFF). Small satellites have also made significant advancements over the past two decades with the number of missions launched annually increased by orders of magnitude over that time span. Small satellites offer several advantages compared to …
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Development of thermal field-flow fractionation for the characterization of hybrid nanoparticles and polymers with complex architecture
Field-flow fractionation (FFF) is a family of analytical techniques designed for the separation of macromolecules and colloids on the nanometer to micron scale. The well-established theory governing FFF separations permits physiochemical properties to be calculated from measured analyte retention …
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Fused filament fabrication to manufacture three- and four-dimensional objects made of shape memory polymers
… AM technologies, fused filament fabrication (FFF) is a hot-melt extrusion-based 3D printing process and is widely prevalent. The doctoral thesis aims to utilize self-synthesized and commercially available TPUs for FFF and to specifically influence the printing technology to produce either …
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Printing on Objects: Curved Layer Fused Filament Fabrication on Scanned Surfaces with a Parallel Deposition Machine
… most common type, Fused Filament Fabrication (FFF), has systematically improved and sales have increased, fundamentally, the capabilities of the machines have remained the same. FFF printers are still limited to depositing layers onto a flat build plate. This makes it difficult to combine …
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Improving the strength of fused filament fabrication parts by non-planar alignment of material extrusion wih stress vectors
Fused Filament Fabrication (FFF), a prominent additive manufacturing technique, has been limited in producing end-use parts due to significant anisotropy and weak interlayer bonding. This thesis presents a novel approach to improve mechanical properties of FFF-produced parts through non-planar …
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A joule heating mechanism for high-speed fused filament fabrication
… known as fused filament fabrication (FFF), is one the most accessible methods of rapid prototyping, capable of handling a wide variety of engineering thermoplastics. Productivity limitations hinder the further application of FFF to both prototyping and production. An FFF system …
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Physics Based Modeling and Characterization of Filament Extrusion Additive Manufacturing
… referred to as fused filament fabrication (FFF), is one of the most well-known AM modalities using a polymeric feedstock; however, several obstacles currently prohibit widespread use of this manufacturing technique to produce end-use products, which will be discussed in this dissertation. …
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Modification of Fused Filament Fabrication Printer to Print High Temperature Thermoplastics to Improve Z-Strength
A fused filament fabrication (FFF) desk top three dimensional printer was modified with a pre-deposition heating method using an infrared heat lamp in an omega shape around the printing nozzle to print high temperature materials and improve the tensile and flexural properties. The FFF additive …
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Vliv výběru typu a energie fotonového svazku na ozařovací plán při zevní radioterapii karcinomu děložního hrdla
… with and without a flattening filter (FF and FFF). The evaluated parameters included the volume of the body receiving at least 10 % of the prescribed dose and the total irradiation time. The results showed differences between the individual energies both in the extent of irradiated healthy …
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Toolpath Planning Methodology for Multi-Gantry Fused Filament Fabrication 3D Printing
… prototype products. Fused filament fabrication (FFF) is one of the most popular processes in AM as it is inexpensive, requires low maintenance, and has high material utilization. However, the biggest drawback that prevents FFF printing from being widely implemented in large-scale production is …
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