Engineering Commons^™

Developing A Control System To Better Understand The Effects Of Pyruvate Decarboxylase Activity On Clostridium Thermocellum Metabolism, Nicholas Cervenka

ENGS 88 Honors Thesis (AB Students)

In order for cellulosic biofuels from Clostridium thermocellum to be commercially viable, the ethanol yield and titer of the microbe must be increased. To accomplish this, it has been suggested to introduce the Pyruvate Decarboxylase (PDC) enzyme into C. thermocellum. In order to demonstrate effects on ethanol production by PDC prior to genetic modification, a cell free system (CFS) has been developed. A purified enzyme system was developed with the CFS to function as a control. Using the purified enzyme system, PDC from Saccharomyces cerevisiae was demonstrated to be a good candidate for further testing in the CFS.

Shape Effects Of Gold Coated Silica Nanoparticles For Localized Plasmonic Resonance Based Biosensing, Russell Beckerman

ENGS 88 Honors Thesis (AB Students)

Gold coated silica (Au@SiO₂) nanoparticles are promising optical transducers for biosensors due to localized surface plasmonic resonance (LSPR) sensitivity to changes in refractive index. This study investigates the effects of shape, size, and structure on LSPR sensitivity of Au@SiO₂ nanoparticles of spherical, rod, and ellipsoid geometries. Finite-difference time domain simulations in CST were used to examine these key parameters of interest and guided particle synthesis. Simulation and experiments show rod-shaped Au@SiO₂ nanoparticles had maximum sensitivity of 969nm/RIU, an improvement over most particles in current literature. This study examines a method for enhanced LSPR-biosensors that leverages advances …

Bandpass: A Smart Resistance Exercise Band To Monitor Strength, Suehayla Mohieldin

ENGS 88 Honors Thesis (AB Students)

Resistance exercise bands are being incorporated into clinical weight loss programs, particularly for older adults, as resistance training can mitigate the trajectory of muscle mass and bone density loss that can occur while dieting. However, adherence to home-based treatments cannot be reliably ascertained by clinicians as there is no method for clinicians to monitor patient compliance outside of the clinic. BANDPASS, a smart resistance band used for exercise, was developed to bridge the gap between clinicians and patients, allowing for easy remote monitoring of patients’ exercise performance. The device integrates a 10kΩ linear potentiometer to TheraBand® tubing. When the user …

A Physical And Computational Reverse-Engineering Approach To Determine Dimensional Change And Its Relationship To Oxidation In Retrieved Orthopedic Implants, Josephine Kalshoven

ENGS 88 Honors Thesis (AB Students)

Oxidation of the Ultra-High Molecular Weight Polyethylene (UHMWPE) tibial inserts of total knee arthroplasty devices is a major factor underlying multiple modes of failure for these devices, including delamination, wear, and fracture. Previous research has demonstrated that oxidation of UHMWPE is driven by a high concentration of free radicals in the polyethylene. However, even new devices created with undetectable amounts of free radicals are oxidizing in vivo. One theory is that, in the absence of residual free radicals, oxidation is facilitated by absorbed species (e.g. lipids, ROS) delivered or exacerbated by contact stress. However, no method exists to comprehensively …

Development Of An Rfid Tracking System For Coarse Sediment Transport In A Flume Setting, Peter Mahoney Jr.

ENGS 88 Honors Thesis (AB Students)

Development of an RFID Tracking System for Coarse Sediment Transport in a Flume Setting

Peter E. Mahoney

Professor Carl Renshaw

Understanding how sediment moves through a fluvial system has important implications for the study of river systems, sediment flux, and flood events. Over the past decade, RFID (radio frequency identification) technology has emerged as a useful method for tracking the movement and transport of coarse sediment clasts. This approach has been used to measure the transport of large clasts in mid-sized streams, ephemeral channels, and laboratory flume settings. However, this research utilized finite transport of sediment and focused on accurately …

Surface Engineering Of Annealed High Entropy Alloys Towards Thermodynamically Stable, Anti-Oxidation, Solar Selective Absorbers, Sheppard R. Somers

ENGS 88 Honors Thesis (AB Students)

Concentrating solar power (CSP) systems require receivers that maintain their physical properties at the high operating temperature and are absorbent. The high entropy alloy Fe28.2Ni18.8Mn32.9Al14.1Cr6 (HEA) investigated in this thesis fills these needs by harnessing the HEA’s oxidation process to create a selective solar absorbing layer that grows at a parabolic rate at CSP operating temperatures. Results of this research demonstrate that annealing processes of HEA can yield over 90% solar thermal efficiency by engineering the surface oxidation to be both physically and optically optimized for absorption.

Spatial Frequency Domain Imaging Of Short-Wave Infrared Fluorescence For Biomedical Applications, Joseph P. Leonor

ENGS 88 Honors Thesis (AB Students)

Fluorescence imaging has become a standard in many clinical applications, such as tumor and vasculature imaging. One application that is becoming more prominent in cancer treatment is fluorescence-guided surgery (FGS). Currently, FGS allows surgeons the ability to visually navigate tumors and tissue structures intraoperatively. As a result, they can remove tumor more efficiently while maintaining critical structures within the patient, creating better outcomes and lower recovery times. However, background fluorescence and inability to localize depth create challenges when determining resection boundaries.

Different techniques, such as spatially modulating the illumination and imaging at longer light wavelengths, have been developed to accurately …

Feasibility Study Of Dartmouth's Renewable Energy Future, Lily R. Hanig

ENGS 88 Honors Thesis (AB Students)

This is a feasibility study of Dartmouth's Renewable Energy propositions. This study analyzes the carbon offsets of implementing a 13 MW solar PV system at Oak Hill. This study used the Energy Database to calculate the carbon emissions of the college for 2010 (the baseline year) and 2018. It also projected carbon emissions for the year 2025 assuming the Oak Hill solar PV system is implemented as outlined and the biomass plant is implemented with similar fuel ratios to nearby biomass plant projects. It was found that Dartmouth should sufficiently make its carbon emissions reductions goals for 2025.

Modeling The Economic Machine Using Bayesian Inference And Statistical Networks, And Optimal Portfolio Construction Using Operations Research, Richard Yang

ENGS 88 Honors Thesis (AB Students)

In this paper, we propose a network-based model to attempt to connect modern macroeconomic theory with real world economic observations and trends. We find that by extending macroeconomic theory with credit leveraging/deleveraging thresholds, we are able to explain economic cycles in addition to long-term growth. Furthermore, we specifically explore the growth-inflation view of the macro economy as a basis for optimal portfolio construction and efficient asset trading. Connecting our network-based macroeconomic model and our optimal portfolio construction algorithm, we create a novel macroeconomic asset-trading framework.

Pairing A Robot To A Virtual Entity To Provide Haptic Feedback In Virtual Reality, Tristan G. Fogt

ENGS 88 Honors Thesis (AB Students)

Virtual reality (VR) environments are most commonly used for entertainment and gaming, though are also employed in rehabilitative and professional contexts. Virtual reality systems currently have highly convincing visual and aural feedback, allowing for a superficially immersive experience for the user. However, these systems lack haptic feedback, breaking the immersive experience as soon as the user tries to interact with a virtual object or entity physically, which severely limits the uses of VR.

To solve this, instead of the conventional approach of trying to simulate feeling something that isn’t actually there, a physical robot was created to exist in real …

Impact In Practice, Maria Garman

ENGS 88 Honors Thesis (AB Students)

Medial Tibial Stress Syndrome (Shin splits) is an overuse injury caused by repetitive impact. If ignored it can lead to stress reactions and then stress fractures in the shins. This nagging injury is something that plagues many track athletes especially as they start to wear their competition shoes more frequently at practice to work on technical aspects of their events.

This paper investigates the relationship between ground reaction forces experienced by the athletes in each stride and what shoes they are wearing on their feet. Due to the fact that repetitive impact is a cause for shin splints, the conclusion …

Abso2luteu-Net: Tissue Oxygenation Calculation Using Photoacoustic Imaging And Convolutional Neural Networks, Kevin Hoffer-Hawlik, Geoffrey P. Luke

ENGS 88 Honors Thesis (AB Students)

Photoacoustic (PA) imaging uses incident light to generate ultrasound signals within tissues. Using PA imaging to accurately measure hemoglobin concentration and calculate oxygenation (sO₂) requires prior tissue knowledge and costly computational methods. However, this thesis shows that machine learning algorithms can accurately and quickly estimate sO₂. absO₂luteU-Net, a convolutional neural network, was trained on Monte Carlo simulated multispectral PA data and predicted sO₂ with higher accuracy compared to simple linear unmixing, suggesting machine learning can solve the fluence estimation problem. This project was funded by the Kaminsky Family Fund and the Neukom Institute.