Engineering Commons^™

Production Of Ethanol From Hardwood, Jay Mitchell

Electronic Theses and Dissertations

Diminishing crude oil and natural gas supplies, along with concern about greenhouse gas are major driving forces in the search for efficient renewable energy sources. The conversion of lignocellulosic biomass to energy and useful chemicals is a component of the solution. Ethanol is most commonly produced by enzymatic hydrolysis of complex carbohydrates to simple sugars followed by fermentation using yeast.

C₆H_l0O₅ + H₂O −Enxymes→ C₆H₁₂O₆ −Yeast→ 2CH₃CH₂OH + 2C0₂

In the U.S. corn is the primary starting raw material for commercial ethanol production. …

High-Speed Digital And Mixed-Signal Components For X– And Ku–Band Direct Digital Synthesizers In Indium Phosphide Dhbt Technology, Steven Eugene Turner

Electronic Theses and Dissertations

Recently reported double heterojunction bipolar transistor (DHBT) devices manufactured in Indium Phosphide (InP) technology with ft and fmax both over 300 GHz enable advanced high-speed digital and mixed-signal circuits. In this thesis, the use of InP DHBT devices for high-speed accumulator circuits and X– and Ku–band direct digital synthesizer (DDS) circuits are investigated. At these frequencies, new technological challenges in the design of digital and mixed-signal circuits arise in areas including power consumption and clock distribution. This thesis addresses the speed/power tradeoffs in high-speed accumulator designs, the design of DDS circuits, and clock distribution simulation. The results of six accumulator …

A Durability And Utility Analysis Of Efpi Fiber Optic Strain Sensors Embedded In Composite Materials For Structural Health Monitoring, Adam Benjamin Haskell

Electronic Theses and Dissertations

The objective of the research work was to develop a method to embed fiber optic sensors (FOS) that measure strain in polymer matrix composite (PMC) laminates and sandwich composite panels, to apply the technology to structural health monitoring, and to assess the durability of the sensor system through a fatigue test protocol applied to sandwich composite panels. There is a growing interest in determining and monitoring the performance and sustainability of structures such as bridges, buildings, marine vessels, and aerospace structures. By monitoring structural elements, damage to the structure can be detected resulting in more efficient repair and maintenance schedules, …

Coastal Sediment And Fish Biosolids Remediation Using A Microbial Fuel Cell, Eric George Para

Electronic Theses and Dissertations

Abstract

Organic pollution of marine and freshwater environments has long been a problem due to spills, shipping or boating activity, runoff, and waste discharge. Microbial Fuel Cells (MFC) harness electrons released during the oxidation of organic carbon to produce an electric current. Hydrocarbons are normally broken down into carbon dioxide and water by microbial respiration, where electrons from hydrocarbons are transferred to an electron acceptor such as oxygen. In sediment, however, oxygen is consumed within the top few centimeters, and other electron acceptors such as sulfate yield less energy, which slows the degradation process. A MFC anode placed in the …

Structural Design Of Hollow Extruded Wpc Sheet Piling, Melissa Kahl

Electronic Theses and Dissertations

In marine environments, materials are exposed to a number of harsh environmental factors. Traditional retaining wall materials experience severe degradation as a response to these factors. To address these degradation issues, wood plastic composite (WPC) materials can be used in marine sheet pile applications. WPC materials are both lightweight and durable. This research focuses on developing a sheet pile design that utilizes the material benefits of extruded wood plastic composites with a voided z section sheet pile geometry. The objectives are to develop a more efficient structural design in terms of both material and geometry as compared to the polyvinylchloride …

Remote Sensing And Data Collection In A Marine Science Application, Isaac Abraham Horn

Electronic Theses and Dissertations

In every field of science, research is driven by the data scjentists are able to collect. Specifically in the area of marine science, researchers at the Darling Marine Center (DMC) in Walpole, Maine study thc emergence events of undersea organisms. This thesis describes the development of a system integrating hardware infrastructure and existing software technology with a new software application, for the purpose of data acquisition at the DMC. In their research, a Tracor Acoustic Profiling System (TAPS), measures the water column density by utilizing sonar pulscs at several different frequencies. A serial interface provides access to the systems command …

Structural Testing And Analysis Of Hybrid Composite/Metal Joints For High-Speed Marine Structures, Jean Paul Kabche

Electronic Theses and Dissertations

The implementation of composite materials in engineering applications has observed a rapid increase over the last few decades. The U.S. Navy currently has an objective to enhance its future naval capabilities by developing hull-forms with advanced materials, including composites. Speed can be increased by reduction in weight and by incorporating innovative shaping of the hull-form, which can potentially be achieved with composites. Any naval vessel using composite materials for structural components will require hybrid connections of some sort, where composite sections are joined to metallic sub-structures. Joints are critical regions in the design of hybrid systems, as failures typically occur …