Engineering Commons^™

Monitoring Aerosols With Time Resolution With A Rotating Drum Sampler Using La-Icpms For Elemental Analysis, John V. Piorkowski

Honors Theses

This thesis presents a comprehensive study on the characterization and application of a rotating drum sampler for air quality monitoring, with a focus on aerosol composition analysis using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). The study aimed to determine (1) the cut-off points of the drum sampler to better understand its performance characteristics and (2) to investigate indoor air quality, specifically within makerspaces on Bucknell University’s campus. The research highlighted the novelty of applying LA-ICPMS for time-resolved aerosol composition analysis, demonstrating the potential for low-cost pollution concentration studies. The characterization experiments did not yield expected results, but the …

Experimental Evaluation Of Mesh Size In Physically Crosslinked Polymer Gels Using Dynamic Light Scattering, Duncan M. Hill

Honors Theses

Block copolymer gels are under consideration as drug delivery patches. Controlling and modeling the transport inside the gel is an important contribution to the successful delivery of pharmaceuticals. The diffusive transport of a solute – such as a therapeutic compound – within the gel can be described by the mesh size of the gel, which is defined as the distance between polymer chains. Existing experimental evaluations of mesh size do not work for block copolymer gels due to differences in the fundamental gel structure. As such, an experimental method of measuring mesh size of block copolymer gels using dynamic light …

The Precedence-Constrained Quadratic Knapsack Problem, Changkun Guan

Honors Theses

This thesis investigates the previously unstudied Precedence-Constrained Quadratic Knapsack Problem (PC-QKP), an NP-hard nonlinear combinatorial optimization problem. The PC-QKP is a variation of the traditional Knapsack Problem (KP) that introduces several additional complexities. By developing custom exact and approximate solution methods, and testing these on a wide range of carefully structured PC-QKP problem instances, we seek to identify and understand patterns that make some cases easier or harder to solve than others. The findings aim to help develop better strategies for solving this and similar problems in the future.

Computationally Modeling The Human-Structure Interaction Response Of An Occupied Cantilevered Structure, Brennan Smith

Honors Theses

There is a limited understanding of the impact that passive human occupants have on a dynamic structural system, referred to as Human-Structure Interaction (HSI). Cantilevers are naturally prone to excessive vibrations due to their long unsupported spans, and cantilevered structures such as those commonly found in the seating area of a stadium facility or concert hall are designed to support a high density of occupancy.

This study determined that HSI in cantilevered structures can be modeled using a simple two-degree-of-freedom system. The results of the model were validated by data that was collected on a small-scale laboratory structure intentionally designed …

Hygroscopic Tandem Differential Mobility Analyzer (Htdma) Design And Testing For Aerosol Hygroscopic Behavior Studies, Ziheng Zeng

Honors Theses

Most particles in the atmosphere take up water when exposed to increasing relative humidity (RH), and this behavior is described and quantized by a hygroscopicity parameter, kappa. Hygroscopic Tandem Differential Mobility Analysis (HTDMA) can be used to measure the physicochemical properties of aerosol particles and study phenomena that lead to size changes in submicron aerosol particles. Specifically, HTDMA measures how aerosol particles of different initial dry sizes grow or shrink when exposed to changing RH. HTDMA uses two differential mobility analyzers (DMAs) and a humidification system to make these measurements. One DMA selects a narrow size range of dry aerosol …

An Investigation Into Aluminum’S Torsional Behavior Of Circular, Rectangular, And Square Cross-Sections, Marly Mcclintock

Honors Theses

The Specifications for Aluminum Structures (2020) provides the standards that structural engineers follow for aluminum design. Included in these specifications are limit state equations that use strength properties to calculate a member’s initial yield, full yield, and rupture values. One limit state that the standards currently neglect is the torsional failure of solid bars. Torsion is the act of rotation caused by a twisting force, otherwise known as torque. Future installments of the specifications hope to include torsional yielding and rupture equations, so this study investigates the validity of these proposed equations.

Two different aluminum alloys were investigated for this …

Analysis Of The Epidemiology Of Playground-Related Injuries In Relation To Existing Playground Safety Standards: How Should We Address Safe Play?, Drew Filchner

Honors Theses

Play is widely acknowledged to provide children with various physical, emotional, social, and intellectual benefits. However, playgrounds are reported to be the leading location of unintentional recreation injuries to children aged 1-10. Over 185,000 children annually are being treated in emergency departments for playground injuries. These play-related injuries have remained stagnant according to epidemiology studies of the past three decades. Past epidemiological studies for playground injuries have been based on emergency department data, resulting in an underrepresentation of the magnitude of injuries occurring. This study utilizes the unique setting of an entire school district, providing a more comprehensive understanding of …

Sustainable Polylactic Acid Foam Development Through Solid-State Processing, Philip Onffroy

Honors Theses

Plastics play a vital role in global materials industries, but they contribute to environmental and ecological toxicity effects that accelerate climate change. One important category of plastic material is polymer foams, which have widespread applications in insulation, packaging, and storage. Current bio-based plastic foams that originate from natural, non-petroleum feedstocks are potential solutions but do not yet have adequate properties to supplant petrochemical-based plastic foams. This project aims to generate, test, and analyze bio-based polylactic acid (PLA) polymer foams developed through methods involving solid-state processing such as solid-state shear pulverization (SSSP) and cryogenic milling. SSSP has previously been shown to …

What Makes An Expert? Characterizing Perceptions Of Expertise And Intuition Among Early-Career Engineers, Caroline Bolton

Honors Theses

This thesis seeks to characterize if and how practicing engineers’ perceptions of expertise development, decision-making processes, and engineering intuition vary by aspects of identity, specifically gender and career stage. This thesis is built from ongoing work of the Miskioğlu group on the relationship between expertise and intuition in engineering. Intuition is a characteristic of experts used in decision-making, and the importance of experience in the development of expertise is well documented in literature. There is a gap around how intuition relates to experience, prompting the need to compare the perceptions of early career engineers and mid-to-late career engineers. This thesis …

Determination Of Hydrogel Degradation By Passive Mechanical Testing, Avery Rosh-Gorsky

Honors Theses

This paper details a new technique to measure the mechanical properties of ETTMP PEGDA hydrogels using Hertz Contact Theory and simultaneously analyze both the model drug release and gel erosion in situ. This method involves curing a drug loaded hydrogel in a standard cuvette and placing a glass bead and phosphate buffer solution (PBS). Over time, the cross-linked network of the hydrogel breaks down, and, as a result, the ball sinks into the hydrogel. This method provides a macroscopic and inexpensive way to continuously and passively measure properties of the hydrogel as the hydrogel degrades. By plotting both the …

Assessing Solvent Viscosity Impact On The Physical Characteristics Of Polymeric Organogels, Cameron Hong

Honors Theses

Traditionally, studies of polymeric organogels focus on the impact of polymer factors (e.g., molecular weight and polymer concentration) on the gels’ mechanical and transport properties. Alternatively, this study seeks to assess the impact of altering solvent viscosity, while holding polymer factors constant. The gels in this study were composed of different viscosity mineral oils, styrene-ethylene-butylene-styrene (SEBS) triblock copolymer as a gelator, and oleic acid (OA) as a model drug. Samples were formulated to have 6.5, 11.2, and 15.7 wt% SEBS copolymer for each mineral oil, varying in viscosity from ≈30 mPa*s to ≈500 mPa*s. Uniaxial mechanical testing was performed to …

Perceptually Improved Medical Image Translations Using Conditional Generative Adversarial Networks, Anurag Vaidya

Honors Theses

Magnetic resonance imaging (MRI) can help visualize various brain regions. Typical MRI sequences consist of T1-weighted sequence (favorable for observing large brain structures), T2-weighted sequence (useful for pathology), and T2-FLAIR scan (useful for pathology with suppression of signal from water). While these different scans provide complementary information, acquiring them leads to acquisition times of ~1 hour and an average cost of $2,600, presenting significant barriers. To reduce these costs associated with brain MRIs, we present pTransGAN, a generative adversarial network capable of translating both healthy and unhealthy T1 scans into T2 scans. We show that the addition of non-adversarial …

Assessing The Impact Of Block-Selective Homopolymers On The Diffusion Of Payload Through Polymeric Organogels, Ian Coates

Honors Theses

Styrenic polymer gels have received recent attention for their application in transdermal patches due to their unique properties. Previous research in the pharmaceutical industry has identified that polymeric gels, specifically styrenic gels, have the potential to encompass multiple functions of the transdermal delivery patch including controlling mechanical and delivery properties. To tailor styrenic gels either the gel nanostructure or the drug complex can be controlled. Specifically, this thesis investigated the effect of gel nanostructure in an attempt to control the gel diffusivity and mechanical properties. To control gel nanostructure a phase selective styrene homopolymer was used at varying concentrations. It …

Impacts Of Using Tubular Sections In Open Web Steel Joists, Hollis (Cas) L. Caswell V

Honors Theses

Open web steel joists are lightweight structural trusses used in place of I-beams to support long-span floors and roofs of open space buildings. Their slender geometry makes them highly efficient in resisting flexure, but susceptible to out-of-plane buckling in a failure mode known as lateral-torsional buckling. This failure can be avoided by running lateral bracing between joists called bridging or potentially by using tubular sections to build up the joists rather than angle sections.

It is possible that a joist design using tubular cross-sections could require less bridging and prevent the need to use erection bridging for initial joist construction. …

Heavy Metals Found In Juul's Electronic Cigarettes, Joshua F. Gesselberty

Honors Theses

Electronic cigarettes better known as e-cigarettes have been consistently rising in popularity with new products entering the market daily. E-cigarettes function by vaporizing a liquid composed of propylene glycol, glycerin, benzoic acid, nicotine, and flavor additives with the use of a metallic heating element. This vapor produced is then inhaled by the user. The composition of this liquid is critical to discovering the possible health effects.

This study investigates the presence and concentrations of heavy metals in the e-liquid before and after vaping. An ICP-MS was used because of its ability to scan several metals rapidly and its high sensitivity. …

An Investigation Of The Airborne Particulate Matter Related Health Hazards Present In Makerspaces, Justin Keller

Honors Theses

Airborne particulate matter poses several health hazards ranging from pulmonary inflammation to cardiovascular disease. Particulate matter is produced through many fabrication processes common to makerspaces, such as 3D printing and laser cutting. The danger of these particles is worsened when makerspaces are retrofitted into spaces not designed with good ventilation or safety controls, such as libraries and public schools. This thesis evaluates the relationship between makerspaces and hazardous particle generation with both continuous and motion sensor controlled ventilation, showing that the latter creates unsafe working conditions. Both observational and controlled studies were conducted in Bucknell’s Mooney Lab makerspace monitoring particle …

Why Do I Have To Know This? Engineering In A Globalized Society, Caleb Cunningham

Honors Theses

Through a pilot comparative study, this thesis examines the problem-solving of chemical engineering students and chemical engineering faculty. Specifically, the thesis examines the extent to which individuals include global factors (cultural, social, environmental, and economic) into their engineering solutions as specified by ABET. Several hypotheses were investigated in this pilot study: (i) having a study abroad experience would increase the likelihood that participants included the global factors of interest, (ii) the type (PUI, Research Intensive, Unique) of institution students attended would impact how individuals approached the problem, (iii) students with similar career aspirations would approach the problems similarly, (iv) having …

Aqueous And Oil Products From Hydrothermal Liquefaction Of Manure Digestate, Kenzie Burns

Honors Theses

Hydrothermal liquefaction is a promising thermochemical waste-to-energy (WtE) technology for conversion of wet biomasses, such as manure and digested manure, into value-added products, namely energy-rich biofuel and a nutrient-rich aqueous product. WtE technologies can address environmental issues relating to overproduction of organic wastes and increasing dependence on fossil fuels, which leads to climate change. HTL has not been implemented on a commercial scale, in part due to the uncertainty regarding specific reaction pathways for different feedstocks and ideal conditions for production of the most valuable products.

This research investigates the compositions of the aqueous and oil products from HTL of …

Study Of The Compressive Strength Of Aluminum Curved Elements, Christine M. Shepherd

Honors Theses

Currently, the Specification for Aluminum Structures (Aluminum Association, 2010) shows thin-walled aluminum plate sections with radii greater than eight inches have a lower compressive strength capacity than a flat plate with the same width and thickness. This inconsistency with intuition, which suggests any degree of folding a plate should increase its elastic buckling strength, inspired this study. A wide range of curvatures are studied—from a nearly flat plate to semi-circular. To quantify the curvature, a single non-dimensional parameter is used to represent all combinations of width, thickness and radius. Using the finite strip method (CU-FSM), elastic local buckling stresses are …

Modeling Yield Surfaces Of Various Structural Shapes, Oudam Meas

Honors Theses

This study investigates the possibility of custom fitting a widely accepted approximate yield surface equation (Ziemian, 2000) to the theoretical yield surfaces of five different structural shapes, which include wide-flange, solid and hollow rectangular, and solid and hollow circular shapes. To achieve this goal, a theoretically “exact” but overly complex representation of the cross section’s yield surface was initially obtained by using fundamental principles of solid mechanics. A weighted regression analysis was performed with the “exact” yield surface data to obtain the specific coefficients of three terms in the approximate yield surface equation. These coefficients were calculated to determine the …

Performance Characteristics Of Airlift Pumps With Vortex Induced By Tangential Fluid Injection, Jacob Riglin

Honors Theses

The effect of the swirl component of air injection on the performance of an airlift pump was examined experimentally. An airlift pump is a device that pumps a liquid or slurry using only gas injection. In this study, the liquid used was water and the injected gas was air. The effect of the air swirl was determined by measuring the water discharge from an airlift pump with an air injection nozzle in which the air flow had both axial and tangential components and then repeating the tests with a nozzle with only axial injection. The induced water flow was measured …

Investigation Of Solid-State Shear Pulverization Processing Parameters For Polyethylene-Clay Nanocomposites , Ben Aldrich

Honors Theses

Investigates multiple processing parameters, includingpolymer type, filler type, processing technique, severity of SSSP (Solid-state shear pulverization)processing, and postprocessing, of SSSP. HDPE and LLDPE polymers with pristine clay and organo-clay samples are explored. Effects on crystallization, high-temperature behavior, mechanicalproperties, and gas barrier properties are examined. Thermal, mechanical, and morphological characterization is conducted to determine polymer/filler compatibility and superior processing methods for the polymer-clay nanocomposites.

Design Of A Liquid Fuel Injector For Alternative Fuel Studies In An Atmospheric Model Gas Turbine Combustor, John Stevenson

Honors Theses

A new liquid-fuel injector was designed for use in the atmospheric-pressure, model gas turbine combustor in Bucknell University’s Combustion Research Laboratory during alternative fuel testing. The current liquid-fuel injector requires a higher-than-desired pressure drop and volumetric flow rate to provide proper atomization of liquid fuels. An air-blast atomizer type of fuel injector was chosen and an experiment utilizing water as the working fluid was performed on a variable-geometry prototype. Visualization of the spray pattern was achieved through photography and the pressure drop was measured as a function of the required operating parameters. Experimental correlations were used to estimate droplet sizes …

Development Of Measurement Methods For Testing Of Hydrokinetic Devices To Evaluate The Environmental Effect On Local Substrate, Michael Volpe

Honors Theses

Modifications and upgrades to the hydraulic flume facility in the Environmental Fluid Mechanics and Hydraulics Laboratory (EFM&H) at Bucknell University are described. These changes enable small-scale testing of model marine hydrokinetic(MHK) devices. The design of the experimental platform provides a controlled environment for testing of model MHK devices to determine their effect on localsubstrate. Specifically, the effects being studied are scour and erosion around a cylindrical support structure and deposition of sediment downstream from the device.

Investigation Of The Design Of A Bistable Micro-Chemical-Mechanical Device Utilizing Lateral Buckling, Susan Lyn Barnes

Honors Theses

The Gracias Laboratory at Johns Hopkins University has developed microgrippers which utilize chemically-actuated joints to be used in micro-surgery. These grippers, however, take up to thirty minutes to close fully when activated biochemicals in the human body. This is very problematic and could limit the use of the devices in surgery. It is the goal of this research to develop a gripper that uses theGracias Laboratory's existing joints in conjunction with mechanical components to decrease the closing time. The purpose of including the mechanical components is to induce a state of instability at which time a small perturbation would cause …

Investigating The Effects Of Various Crowd Characteristics On The Dynamic Properties Of An Occupied Structure, Robert Joseph Firman Iii

Honors Theses

One of the challenges for structural engineers during design is considering how the structure will respond to crowd-induced dynamic loading. It has been shown that human occupants of a structure do not simply add mass to the system when considering the overall dynamic response of the system, but interact with it and may induce changes of the dynamic properties from those of the empty structure. This study presents an investigation into the human-structure interaction based on several crowd characteristics and their effect on the dynamic properties of an empty structure. The dynamic properties including frequency, damping, and mode shapes were …