A study of heating and degradation of acrylonitrile-butadiene-styrene/polycarbonate polymer due to ultraviolet lasers illumination during localized pre-deposition heating for fused filament fabrication 3D printing

Description
With the growing popularity of 3d printing in recreational, research, and commercial enterprises new techniques and processes are being developed to improve the quality of parts created. Even so, the anisotropic properties is still a major hindrance of parts manufactured

With the growing popularity of 3d printing in recreational, research, and commercial enterprises new techniques and processes are being developed to improve the quality of parts created. Even so, the anisotropic properties is still a major hindrance of parts manufactured in this method. The goal is to produce parts that mimic the strength characteristics of a comparable part of the same design and materials created using injection molding. In achieving this goal the production cost can be reduced by eliminating the initial investment needed for the creation of expensive tooling. This initial investment reduction will allow for a wider variant of products in smaller batch runs to be made available. This thesis implements the use of ultraviolet (UV) illumination for an in-process laser local pre-deposition heating (LLPH). By comparing samples with and without the LLPH process it is determined that applied energy that is absorbed by the polymer is converted to an increase in the interlayer temperature, and resulting in an observed increase in tensile strength over the baseline test samples. The increase in interlayer bonding thus can be considered the dominating factor over polymer degradation.
Date Created
2017
Agent

The Analysis of Solar - Fuel Cell Hybrid Systems

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Description
As the demand for renewable and alternative energy continues to increase with both large industrial companies and average homeowners, there continues to be a challenge of efficient energy storage. Several main alternative energy producers such as wind turbines, hydroelectric dams,

As the demand for renewable and alternative energy continues to increase with both large industrial companies and average homeowners, there continues to be a challenge of efficient energy storage. Several main alternative energy producers such as wind turbines, hydroelectric dams, and solar photovoltaic arrays have become more commonly used over the past decade for generating energy. One of the most common issues with these alternative energy producers is the intermittent production and supply of energy due to fluctuations in weather conditions, peak loads, and instantaneous power draw. To counteract these issues, storage units such as battery banks and proton exchange membrane fuel cells are introduced to provide electricity for the unmet energy demands. In this study, a solar photovoltaic array and fuel cell hybrid system has been set up to provide the energy needs for an average Arizona residential household. A bench test setup has revealed that a solar photovoltaic array and the fuel cell hybrid system can produce enough energy to power an Arizona household that on average consumes 37.7 kWh/d. Additionally, a Mathworks MATLAB/Simulink model of the hybrid system has been created to simulate specific scenarios which provide insight into the system’s reaction to various conditions such as varying solar irradiance and temperature variables and poor weather conditions. Finally, the economic impact of the hybrid system was simulated using HOMER Legacy to analyze the cost effectiveness of a 25-year project.
Date Created
2017
Agent

Hydrogen fuel cell on a helicopter: a system engineering approach

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Description
Hydrogen fuel cells have been previously investigated as a viable replacement to traditional gas turbine auxiliary power unit onboard fixed wing commercial jets. However, so far no study has attempted to extend their applicability to rotary wing aircrafts. To aid

Hydrogen fuel cells have been previously investigated as a viable replacement to traditional gas turbine auxiliary power unit onboard fixed wing commercial jets. However, so far no study has attempted to extend their applicability to rotary wing aircrafts. To aid in the advancement of such innovative technologies, a holistic technical approach is required to ensure risk reduction and cost effectiveness throughout the product lifecycle. This paper will evaluate the feasibility of replacing a gas turbine auxiliary power unit on a helicopter with a direct hydrogen, air breathing, proton exchange membrane fuel cell, all while emphasizing a system engineering approach that utilize a specialized set of tools and artifacts.
Date Created
2016
Agent