Wind Turbine Blade Recycling: An Economic Decision Framework

The objective of this project is to explore the economics behind wind turbine blade recycling. The project will determine the current cost of disposing wind turbine blades, and investigate the cost of pursuing other end-of-life alternatives. The goal of the project is to model the economic factors that cause a wind farm owner to dispose of blades in a certain way. Examples of economic factors would include cost of recycling equipment, distance from wind farm to equipment, selling price of recycled output, etc. The project will involve studying the cost of existing methods of wind blade decommissioning, as well as proposing costs for recycling methods

Automated Manufacturability Analysis for Conceptual Design in New Product Development

This paper presents ANA, a software package that provides automated manufacturability feedback to product designers, enabling first time quality of design and avoiding later stage change requests. Manufacturing knowledge is critical to the design process. Decisions made early in the conceptual design phase can significantly affect downstream production cost. Manufacturing engineers may have a limited role in the design process which can lead to designs that are difficult to manufacture. ANA is the implementation of numerous feature-free geometric algorithms that determine manufacturability metrics related to machining, casting, die-casting, and welding processes. These metrics are accompanied by colored 3D graphical models to provide rich feedback similar to finite element models, for example. The iterations of a design are tracked over time, allowing users to review how certain design decisions impact the expected manufacturability of the part. ANA is intended for use inside existing CAD systems, in the cloud, or as a standalone application. The feedback from ANA, combined with built-in learning modules, aids the user in making design improvements and assists in selecting an appropriate manufacturing process. This feedback can be shared across platforms via interactive 3D PDFs

Solid-state ensemble of highly entangled photon sources at rubidium atomic transitions

Semiconductor InAs/GaAs quantum dots grown by the Stranski-Krastanov method are among the leading candidates for the deterministic generation of polarization entangled photon pairs. Despite remarkable progress in the last twenty years, many challenges still remain for this material, such as the extremely low yield (<1% quantum dots can emit entangled photons), the low degree of entanglement, and the large wavelength distribution. Here we show that, with an emerging family of GaAs/AlGaAs quantum dots grown by droplet etching and nanohole infilling, it is possible to obtain a large ensemble (close to 100%) of polarization-entangled photon emitters on a wafer without any post-growth tuning. Under pulsed resonant two-photon excitation, all measured quantum dots emit single pairs of entangled photons with ultra-high purity, high degree of entanglement (fidelity up to F=0.91, with a record high concurrence C=0.90), and ultra-narrow wavelength distribution at rubidium transitions. Therefore, a solid-state quantum repeater - among many other key enabling quantum photonic elements - can be practically implemented with this new material

Nonlinear Schrödinger equations and the universal description of dispersive shock wave structure

The nonlinear Schrödinger (NLS) equation and the Whitham modulation equations both describe slowly varying, locally periodic nonlinear wavetrains, albeit in differing amplitude-frequency domains. In this paper, we take advantage of the overlapping asymptotic regime that applies to both the NLS and Whitham modulation descriptions in order to develop a universal analytical description of dispersive shock waves (DSWs) generated in Riemann problems for a broad class of integrable and non-integrable nonlinear dispersive equations. The proposed method extends DSW fitting theory that prescribes the motion of a DSW's edges into the DSW's interior, i.e., this work reveals the DSW structure. Our approach also provides a natural framework in which to analyze DSW stability. We consider several representative, physically relevant examples that illustrate the efficacy of the developed general theory. Comparisons with direct numerical simulations show that inclusion of higher order terms in the NLS equation enables a remarkably accurate description of the DSW structure in a broad region that extends from the harmonic, small amplitude edge

Stationary expansion shocks for a regularized Boussinesq system

Stationary expansion shocks have been recently identified as a new type of solution to hyperbolic conservation laws regularized by non-local dispersive terms that naturally arise in shallow-water theory. These expansion shocks were studied in [1] for the Benjamin-Bona-Mahony equation using matched asymptotic expansions. In this paper, we extend the analysis of [1] to the regularized Boussinesq system by using Riemann invariants of the underlying dispersionless shallow water equations. The extension for a system is non-trivial, requiring a combination of small amplitude, long-wave expansions with high order matched asymptotics. The constructed asymptotic solution is shown to be in excellent agreement with accurate numerical simulations of the Boussinesq system for a range of appropriately smoothed Riemann data

Expansion shock waves in regularised shallow water theory

We identify a new type of shock wave by constructing a stationary expansion shock solution of a class of regularised shallow water equations that include the Benjamin-Bona-Mahoney (BBM) and Boussinesq equations. An expansion shock exhibits divergent characteristics, thereby contravening the classical Lax entropy condition. The persistence of the expansion shock in initial value problems is analysed and justified using matched asymptotic expansions and numerical simulations. The expansion shock’s existence is traced to the presence of a non-local dispersive term in the governing equation. We establish the algebraic decay of the shock as it is gradually eroded by a simple wave on either side. More generally, we observe a robustness of the expansion shock in the presence of weak dissipation and in simulations of asymmetric initial conditions where a train of solitary waves is shed from one side of the shock

Geometric Analysis to Automate Design for Supply Chain

This paper presents a method for using geometric algorithms to characterize CAD models for the purpose of automated design for supply chain. Improvements in computing allow for fast manufacturability analysis of the 3D geometry found in CAD files. For example, designers can determine the percentage of a 3D model that can be machined, or how many cores would be required to produce a sand casting of the model. Traditionally, this kind of information has been used for process planning or reducing cost via design for manufacture. However, market pressures and product complexity cause firms to outsource fabrication to external suppliers. It is therefore necessary to understand how early design decisions will impact the sourceability of a design, which encompasses cost, quality, and lead time in the supply chain. The goal of this research is to use geometric characterizations and production requirements of a conceptual design to automatically predict sourceability, and provide feedback that enables proactive design changes. This paper works toward this goal by providing a correlation analysis of geometry-based metrics of models classified by manufacturing process