Global ETD Search
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 21 for “"process window"”.
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Process window and variation characterization of the micro embossing process
The micro embossing process on polymethylmethacrylate (PMMA) is demonstrated experimentally to be a useful process to produce micro fluidic and optical devices. Because this process is a one step thermoplastic deformation process, it is possible to reach high production rates and low cost in …
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Computational-Experimental Process Development for Laser Powder Bed Fusion Additive Manufacturing
… with powder handling, identification of process parameters, part qualification and quality control, and low build rates that lead to high part costs. This thesis presents workflows, tools, and understanding for practitioners and researchers seeking to address these challenges, in …
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Characterization of the Performance Variation for Regular Standard Cells with Process Non-idealities
… of standard cells often varies due to process non-idealities. Some research work on 2-D cell characterization shows that the timing variations can be characterized by the timing model. However, as regular design rules become necessary in sub-45 nm node circuit design, 1-D design has …
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Copper contamination in end-of-life steel recycling, developing a new strategy from million-tonnes to milligrams
… separation. Beyond hand-picking, no commercial process exists for extraction, but copper in solution with steel segregates during hot rolling, causing surface cracking and defects that are unacceptable for high-quality flat products. This thesis characterizes copper in the global steel system, …
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Improving mechanical properties of a magnesium alloy by severe plastic deformation
… angular pressing (I-ECAP). The goal of the process is to refine grain structure of a continuous bulk metallic billet without changing its dimensions. In the current work, the most popular wrought magnesium alloy AZ31B was subjected to I-ECAP for the first time to confirm potential of the …
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Fluid Mechanics of High Speed Deformable Roll coating. An experimental and theoretical study of film thickness and stability in high speed deformable roll coating flow with Newtonian and non-Newtonian liquids
… which is primarily determined by an optimum process window, is affected by non-uniformities and instabilities originating at higher operation speeds. Unlike other academic works, because of associated industrial relevance, particular attention was given towards the use of industrially …
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Fabrication and qualification of arbitrarily patterned seamless tooling for continuous roll-to-roll microcontact printing
… when compared with other printing and patterning processes. Traditional microcontact printing using flat stamps and planar, rigid substrates, which limit production output, manufacturing scale, and capital efficiency. However, a precise, scalable, roll-to-roll process could lower production costs, …
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A Metamodel based Multiple Criteria Optimization via Simulation Method for Polymer Processing
… companies, it is important to design reliable processes. To analyze and improve the processing of plastic parts, advanced computer simulation tools have been developed. Yet, the difficulty of optimizing polymer processes is that the performance measures (objectives) involved usually show …
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Processing rate and energy consumption analysis for additive manufacturing processes : material extrusion and powder bed fusion
… in material extrusion and powder bed fusion processes. In all the models developed for these two processes, processing rate is bounded by an adiabatic rate limit at which all the input energy is perfectly utilized to heat up the material to its molten/flowable state. In material extrusion, …
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Applications of photolithographic techniques : materials modeling for double-exposure lithography and development of shape-encoded biosensor arrays
… mode, only marginal image quality and process window improvements were ob- served. Using the results from the simulation work described herein, materials development work is currently ongoing to enable potential ISTP and OTL materials for manufacturing. A new biochip platform named …
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Demolding of hot embossed polymer microstructures
… these devices are miniaturized molding processes including casting, injection molding, and hot embossing. These techniques have in common the use of a mold to define the shape of functional features (fluidic channels), the separation of the part from the mold as a process step …
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Additive Manufacturing of Aluminium-Metal Matrix Composite developed through Mechanical Alloying
… to the complexity of the laser melting process, metal/ceramic feedstock for the process and the reaction of the feedstock material to the laser. Thus an understanding of the process, material microstructure and mechanical properties is important for its adoption as a manufacturing route …
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In Situ Alloying of Titanium via Laser Powder Bed Fusion
… Ti-based alloy development directly during LPBF processing. The first stage of this work investigates a binary Ti–2.9Cu alloy fabricated from blended Ti and Cu powders. An optimal process window was established, yielding near-fully dense, crack-free samples. The as-built alloy comprised α-laths …
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Surface integrity of laser cutting nitinol shape memory alloy
… kerf on Nitinol, and the non-contact thermal process can also eliminate pressing issues inherent in mechanical cutting. Conventional dry laser cutting is a high-temperature process which may generate thermal damage such as heat affected zone (HAZ), recast layer, micro-cracks, and tensile …
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COOLING THEORY FOR THERMOPLASTIC MATERIALS USED IN SCREW EXTRUSION ADDITIVE MANUFACTURING
… numerous software solutions for predictive process simulation as well as active feedback print controls for parameters optimization are emerging, common practice still relies on restricted set of strategies deduced by trial and error testing sessions; the best printing configuration is …
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Thermal homogeneity and energy efficiency in single screw extrusion of polymers. The use of in-process metrology to quantify the effects of process conditions, polymer rheology, screw geometry and extruder scale on melt temperature and specific energy consumption
Polymer extrusion is an energy intensive process whereby the simultaneous action of viscous shear and thermal conduction are used to convert solid polymer to a melt which can be formed into a shape. To optimise efficiency, a homogeneous melt is required with minimum consumption of process energy. …
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Deposition of p-type metal oxide semiconductors for large-area electronic display and solar cell applications
… using industry compatible, chemical deposition processes: atomic layer deposition (ALD) for SnO, due to its very narrow process window and the superior stoichiometric control associated with this deposition technique; and plasma-enhanced chemical vapour deposition (PECVD) for Cu₂O, which as a …
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Modeling and experimental process optimization for a SiH4 + H2 surface wave plasma discharge for silicon photovoltaics
… optimized for 900 MHz microwave excitation. The process gases used were silane (SiH4) and hydrogen (H2). The plasma source was shown to be advantageous in depositing films at very high deposition rate, exceeding 2 nm/s for nc-Si, while deposition of a-Si was observed at 10 nm/s and could be …
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Characterization and modeling of dry etch processes for titanium nitride and titanium films in Cl₂/N₂ and BCl₃ plasmas
… warranted new techniques in their fabrication process which will meet the ever-shrinking dimensions. The gaseous plasma assisted etching is one of these revolutionary processes. However, the plasma and the etch process are very complex in nature. It has been very difficult to understand various …
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Design-technology co-optimization in next generation lithography
… are needed to co-optimize both design and process at the same time. Design-technology co-optimization (DTCO) in next generation lithography (NGL) could be defined very differently under different circumstances. In general, progress in NGL happens along four different directions: • new …
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