Engineering Commons^™

Performance-Limiting Factors For Gaas-Based Single Nanowire Photovoltaics, Xufeng Wang, Mohammad Ryyan Khan, Mark Lundstrom, Peter Bermel

Department of Electrical and Computer Engineering Faculty Publications

GaAs nanowires (NWs) offer the possibility of decoupling light absorption from charge transport for high-performance photovoltaic (PV) devices. However, it is still an open question as to whether these devices can exceed the Shockley-Queisser efficiency limit for single-junction PV. In this work, single standing GaAs-based nanowire solar cells in both radial and vertical junction configurations is analyzed and compared to a planar thin-film design. By using a self-consistent, electrical-optically coupled 3D simulator, we show the design principles for nanowire and planar solar cells are significantly different; nanowire solar cells are vulnerable to surface and contact recombination, while planar solar cells …

The Effects Of Diffusion, Capillary Heterogeneity, And Porous Media Morphology On Co2 Migration In Porous Media, Oluseye Babafemi Adeyemi

Electronic Theses and Dissertations

The Modified Invasion Percolation (MIP) model was used to simulate the invasion of CO2 into a medium initially saturated with water and the style of capillary heterogeneity in combination with buoyancy and viscous forces were varied to yield 105 different simulation scenarios. Thereafter, the invasion of the CO2 gas is simulated using a finite difference model and the effective mass transfer coefficient is determined and linked to various styles of capillary heterogeneity. Results show that an increase in saturation does not result in an increase in mass transfer coefficient rather, the surface area, which in turn is controlled by the …

Noninvasive Measurement Of Cardiac Stroke Volume Using Pulse Wave Velocity And Aortic Dimensions: A Simulation Study, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Background: Concerns about the cost-effectiveness of invasive hemodynamic monitoring in critically ill patients using pulmonary artery catheters motivate a renewed search for effective noninvasive methods to measure stroke volume. This paper explores a new approach based on noninvasively measured pulse wave velocity, pulse contour, and ultrasonically determined aortic cross sectional area. Methods: The Bramwell-Hill equation relating pulse wave velocity to aortic compliance is applied. At the time point on the noninvasively measured pulse contour, denoted th, when pulse amplitude has fallen midway between systolic and diastolic values, the portion of stroke volume remaining in the aorta, and in turn the …

Choosing Inclusion Criteria That Minimize The Time And Cost Of Clinical Trials, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

AIM: To present statistical tools to model and optimize the cost of a randomized clinical trial as a function of the stringency of patient inclusion criteria. METHODS: We consider a two treatment, dichotomous outcome trial that includes a proportion of patients who are strong responders to the tested intervention. Patients are screened for inclusion using an arbitrary number of test results that are combined into an aggregate suitability score. The screening score is regarded as a diagnostic test for the responsive phenotype, having a specific cutoff value for inclusion and a particular sensitivity and specificity. The cutoff is a measure …

Engineering And Engineering Education As Spiritual Vocations, Julia D Thompson, Mel Chua, Cole H. Joslyn

School of Engineering Education Graduate Student Series

Spirituality and engineering (education) are often kept in separate compartments in our lives. They may slip out occasionally for conversations during ethics classes or service learning projects, but speaking -- and living -- our spiritual/religious values as engineers and engineering educators/researchers is still uneasy territory for many. The spirit of free inquiry and reflection that permeates the liberal arts urges us to integrate our spirituality into the human and natural worlds we inhabit. How do we bring such thinking into the technical realms?In this session, we will describe our personal journeys toward engineering education and how we actively and reflectively …

Effect Of Molecular Models On Viscosity And Thermal Conductivity Calculations, Andrew B. Weaver, Alina A. Alexeenko

School of Aeronautics and Astronautics Faculty Publications

The effect of molecular models on viscosity and thermal conductivity calculations is investigated. The Direct Simulation Monte Carlo (DSMC) method for rarefied gas flows is used to simulateCouette and Fourier flows as a means of obtaining the transport coefficients. Experimentalmeasurements for argon (Ar) provide a baseline for comparison over a wide temperature range of 100–1,500 K. The variable hard sphere (VHS), variable soft sphere (VSS), and Lennard-Jones (L-J) molecular models have been implemented into a parallel version of Bird’s one-dimensional DSMC code, DSMC1, and the model parameters have been recalibrated to the current experimental data set. While the VHS and …

A Tale Of Two Design Contexts: Quantitative And Qualitative Explorations Of Student-Instructor Interactions Amidst Ambiguity, Monica E. Cardella, Patrice Buzzanell, Antonette Cummings, Delean Tolbert, Carla B. Zoltowski

Design Thinking Research Symposium

Designers develop design skills and knowledge through experience and feedback – feedback from colleagues, clients, supervisors, users, stakeholders, the success or failure of a solution, and design educators. In this project, we focus on the feedback provided to mechanical engineering students completing their undergraduate studies and industrial design graduate students during design reviews. The design coaches (educators and industry clients) and design students must negotiate ambiguity in the process. The students must reduce ambiguity in the sense of providing clear details as they communicate their design work, reduce ambiguity in the coaches’ perceptions of the design work quality by providing …

Polysemy In Design Review Conversations, Georgi V. Georgiev, Toshiharu Taura

Design Thinking Research Symposium

This paper examines the role of polysemy, defined as the quality of having multiple meanings, in design review conversations. It examines the polysemy, particularly of nouns, involved in a dataset of design review conversations with reference to design ideas. The purpose is to determine whether polysemy is related to successful development of design ideas and more creative design outcomes. The results show that the polysemy of nouns involved in the conversations of the finally developed, successful, design ideas exceeds in the most cases the average polysemy involved in the conversations pertaining to the unsuccessful design ideas. Furthermore, the polysemy of …

A Performance-Based Framework For Structural Resilience To Blast-Induced Damage, Shalva Marjanishvili, Spencer Quiel, Brian Katz

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

This paper proposes a framework for establishing quantitative measures and mathematically reproducible definitions of structural resiliency as it pertains to a structure's ability to minimize the potential for undesirable response to low-probability-high-consequence events. The resiliency assessment and design process follow a logical progression of steps starting with the characterization of hazards and continuing through analysis simulations, damage modeling, and loss assessment by balancing functional relationships between design tradeoffs and associated consequences. The outcomes of each subprocess are articulated through a series of generalized variables: topology, geometry, damage, and hazard intensity measures. A rigorous probabilistic framework permits consistent characterization of the …

A Study On Performance Design Using A Sprinkler System For Fire-Spread Prevention Of A Building Exterior, Seung Un Chae, Heung-You Kim, Uh-Sang Kwon, Bum-Yean Cho

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

A glass exterior material is normally used in buildings, but it also comes with a disadvantage—it is easily damaged by fire. If the glass exterior material is damaged, a fire can rapidly propagate inside the building space, leading to a lot of damage from the flame transfer to the other space. In this study, the performance of a sprinkler for flame propagation prevention was evaluated during an experiment with an actual proof fire. The study found that where the sprinkler is installed with the glass exterior material, the temperature does not exceed 60°C until the end of the test due …

A Multi-Criteria Methodology For Measuring The Resilience Of Transportation Assets And Prioritizing Security Investments, Michelle S. Dojutrek, Samuel Labi, J Eric Dietz

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

Transportation project prioritization uses performance measures that are related to the transportation asset, its operations, and its environment. However, in the state of practice, evaluation does not consider directly the likelihood of natural or man-made threats, the infrastructure resilience, or the consequences of the infrastructure damage in the event that the threat occurs. Thus, during the prioritization of investments, assets of low security do not receive the due attention they deserve. In defining security as the lack of risk of damage from threats due to inherent structure or functional resilience, this paper is based on the premise that the inclusion …

Development Of Resilience Index In Transport Systems, Seungjae Lee, Jooyoung Kim, Shinhae Lee, Yan Chang-Richards

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

This paper demonstrates the quantification of the resilience index (RI) in transport systems. The transport infrastructure can be managed by using the concepts of resilience. Vugrin, Warren, Ehlen, & Camphouse (2010) emphasized the enhancement of resilience in infrastructure before disasters and the establishment of efficient measures for the recovery of systems in an emergency. The concept of resilience has a significant influence on transport planning and operations for disaster preparation. Lee, Kim, & Lee (2013) investigated the concepts of resilience and examined case studies using valuable asset-management techniques in order to maintain the resilience concepts which should be introduced in …

Flood Risk Management: An Illustrative Approach, Natainia S. Lummen, Y Nagayoshi, H Shirozu, T Hokamura, S Nakajo, F Yamada, N Okada

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

Widespread flooding with significant damage in many countries, such as the Philippines in 2013, highlights the ongoing need for effective flood risk management (FRM). This hinges on comprehensive access to and dissemination of information about the elements and the people at risk. Simulations, real-time graphs, and maps illustrate the spatial distribution of flood risks, spatial allocation and dissemination of flood effects, if flood risk reduction measures are not implemented, as well as the benefits to be derived from the effective implementation and maintenance of flood risk management measures not realized. Using precipitation, river water, and tide levels, a real-time monitoring …

Simulation Of Bedrock Motion To Obtain Pga Values, Shyanaka Dananjaya, Ranjith Dissanayake, Nimal Senevirathne, Kushan K. Wijesundara

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

This study is focused on producing the Peak Ground Acceleration (PGA) values for important cities in Sri Lanka, which would provide the base to develop the national annex to the Euro Code, the current guideline in designing structures. In order to find out the magnitude and the epicenter distance of a 475-year return period earthquake, an earthquake catalog was developed. To simulate the bedrock motion FLAC Software, which uses the Finite Difference approach, was used. Five 2-D FLAC models representing five cross sections of Sri Lanka were developed. Due to the lack of local data records, a dataset of seven …

Experimental Study On The Fire Resistance Performance Of Prestressed Composite Beam With Corrugated Web Under Standard Fire With Loading Condition, Heung-Youl Kim, Hyung-Jun Kim, Kyung-Hoon Park, Bum-Yean Cho

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

In this study, fire resistance tests were performed on a conventional slim floor beam and a prestressed composite beam with corrugated webs, which is suitable for a long-span structure with a reduction in story height by utilizing the prestress and accordion effect. In the fire test program, the ISO 834 standard fire curve was adopted. Key test variables were the effect of prestress, shape of corrugated webs, and thickness of sprayed fireproofing material. All of the test specimens demonstrated enhanced fire resistance performance exceeding the expected performance level. The prestressed composite beams with corrugated webs especially showed excellent fire performance, …

Housing The Workforce Following The Canterbury Earthquakes In New Zealand, Yan Chang-Richards, Suzanne J. Wilkinson, Erica Seville, David Brundson

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

Temporary housing following a large-scale disaster has a positive effect on household welfare and community recovery. Following the 2010 and 2011 Canterbury earthquakes, a shortage of temporary accommodation created barriers for the outside construction workforce to engage in repairs and rebuild in Christchurch. This study investigates the impacts of housing shortages for the overall recovery and the strategies adopted by both households and the workforce in the building industry. Findings suggest that the interplay among the industry strategies and household strategies for securing housing determines the magnitude and scope of economy-wide inflation. One unfortunate consequence of these industry strategies is …

The Study On Fire Safety By A Real-Scale Combustion Experiment Of Composite Material, Oh-Sang Kweon, Heung-Youl Kim, Seung-Un Chae, Bum-Yean Cho

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

In this study, a real-scale combustion experiment was carried out for a Styrofoam and glass wool sandwich panel to figure out the fire safety for the composite material used for a building. In the experiment, a heat release rate of a sandwich panel was measured by the ISO 9705 fire test method. Research has also tested and compared temperature change in the Large Scale Calorimeter (LSC) experiment equipment to evaluate the structural safety of the structure body. As a result of the experiment, the structural body with the Styrofoam sandwich panel collapsed which was caused by propagation, and in case …

Experimental Study On Fire Resistance Performance Of A Hollow Slab Using A Lightweight Hollow Sphere, Bum-Yean Cho, Hyung-Jun Kim, Kyung-Hoon Park, Heung-Youl Kim

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

This study evaluates the fire resistance performance (1–2h) of a reinforced concrete (RC) structure-void slab using a lightweight hollow sphere, which can reduce the unnecessary dynamic of removing the central concrete. For this experiment, we set up the depth of the concrete cover, live load, and span length as the factors. The result comes out with 50 mm cover depth of the RC structure hollow slab secured. It was shown that 120 minutes of fire resistance performance can be secured regardless of the length of the structure and loading. Among these factors, the resisting capability changes more sensitively with the …

Motive And Conflict In The Disaster Recovery Process Of Housing Reconstruction In Sri Lanka After The 2004 Indian Ocean Tsunami, Chang Yeol Choi, Riki Honda

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

Normative solutions for the successful recovery from large-scale disasters have been presented by various researches, but implementation requires a long process, and mechanism for the process to continue is necessary. We consider the consistency among strategies of stakeholders such as government and NGOs. These players make a decision based on not only direct motive but various complex motives and interaction with other players. This paper considers interactive decision-making as a game among stakeholders. As a case to study, we analyze housing reconstruction project in Sri Lanka after the 2004 Indian Ocean Tsunami. There was relatively abundant financial support, but the …

Data Preparation For Validation Study Of Hazus Canada Flood Model, Heather Mcgrath, Emmanual Stefanakis, M Mccarthy, Miroslav Nastev

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

As our climate changes, the occurrence of extreme weather events and heavier rainfall becomes more common. This change in weather patterns and precipitation results in a greater number of recorded flood events and a larger magnitude of flood events. Canadian municipalities are therefore facing a pressing demand to perform hazard assessments to identify communities at risk and measure potential economic and societal losses due to flood events. Federal Emergency Management Agency (FEMA) developed a standardized tool, Hazus-MH, for loss estimation from natural disasters for use in the US. Recently, Hazus has been adapted for use in Canada. This paper introduces …

Global Response For Capacity Building Of Disaster Preparedness: A Tiems Initiative, Kåre H. Drager, Thomas V. Robertson

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

At the end of 2013, the devastating consequences of the Typhoon Haiyan that struck the Philippines on November 8, 2013, were exposed worldwide through intensive media coverage. The death toll reached more than 6,000 people, and around one million people were displaced and in desperate need of help and support. The international community queued up to offer support and help and showed that worldwide solidarity works when we know our “brothers and sisters” are in desperate need of help. But how can this international community, eager to respond when disaster strikes, better help before disasters strike? Vulnerable areas in the …

Compare And Contrast Major Nuclear Power Plant Disasters: Lessons Learned From The Past, Sayanti Mukhopadhyay, Makarand Hastak Dr., Jessica Halligan

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

The construction of nuclear power plants is a major step towards reducing greenhouse gas emissions compared to the conventional coal-fired or oil-fired power plants. However, some of the major nuclear accidents in the past have raised questions about the safety and reliability of nuclear power plants. This paper compares and contrasts the major nuclear accidents of the past for example, the Chernobyl disaster (USSR), the Fukushima Daiichi disaster (Japan), and the Three Mile Island incident (USA). Although each of the accidents was unique, a thorough comparison found some common issues, such as faulty design of reactors and safety systems, safety …

Postdisaster Reconstruction Of Horizontal Infrastructure Systems: A Review Of The Christchurch Rebuild, Kristen A. Macaskill

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

This paper investigates the decision-making processes guiding postdisaster infrastructure reconstruction— concentrating on wastewater, water supply, stormwater and road networks (“horizontal infrastructure”). It draws on empirical analysis of the postearthquake reconstruction currently underway in Christchurch, New Zealand.

Restoring infrastructure services to provide at least a basic level of essential services after a disaster helps wider economic recovery. Subsequently, there is pressure to restore infrastructure services to predisaster levels as quickly as possible. Reconstruction programmes thus commence in highly uncertain decision-making environments and are reactive to perceived, immediate needs. The extent and nature of the work is later clarified and re-evaluated as …

Influence Of Decision Making During Disasters And How It Impacts A Community, Jayanrtha Withanaarachchi, Sujeeva Setunge

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

The frequency of natural disasters occurrences has increased and is becoming noticed by many due to the impact on economy, society, and the environment.

Decision making during disasters contributes towards community safety and resilience. Decisions taken to protect people from disasters have an impact on society, economy, environment, travel patterns, and reliability and performance of transport networks.

Decisions often affect the performance of transport networks and critical infrastructure systems during disasters and during demand times. Decision making and decision styles which were observed during disaster events will show the areas that the decisions have worked well or created more risks …

Selecting A Temporary Debris Management Site For Effective Debris Removal, Jooho Kim, Abhijeet Deshmukh, Makarand Hastak

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

The overall debris removal after disasters is often prolonged due to the huge amount of debris and lack of capacities such as a Temporary Debris Management Site (TDMS) in the community. This results in a delay of overall recovery and increases the total recovery cost. Strategic planning and building a TDMS will help in providing extra time for proper disposal of debris and clearing a disaster-impacted site that will facilitate the reconstruction process. This paper presents a unique approach for identifying and selecting TDMS locations for expediting debris removal from the community. A hypothetical example of a community impacted by …

Improving Intersection Behavior Through Delay-Based Left Turn Phase Initiation, Steven M. Lavrenz, Alexander M. Hainen, Amanda L. Stevens, Christopher M. Day, Howell Li, Richard Freije, W Benjamin Smith, Hayley Summers, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

Graphical Performance Measures For Practitioners To Triage Split Failure Trouble Calls, Richard S. Freije, Alexander M. Hainen, Amanda L. Stevens, Howell Li, W Benjamin Smith, Hayley Summers, Christopher M. Day, James R. Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

A Novel Microgrid Demand-Side Management System For Manufacturing Facilities, Terance J. Harper, William J. Hutzel, James C. Foreman, Aaron L. Adams, Athula Kulatunga

Purdue Polytechnic Masters Theses

Thirty-one percent of annual energy consumption in the United States occurs within the industrial sector, where manufacturing processes account for the largest amount of energy consumption and carbon emissions. For this reason, energy efficiency in manufacturing facilities is increasingly important for reducing operating costs and improving profits. Using microgrids to generate local sustainable power should reduce energy consumption from the main utility grid along with energy costs and carbon emissions. Also, microgrids have the potential to serve as reliable energy generators in international locations where the utility grid is often unstable.

For this research, a manufacturing process that had approximately …

Viewing An Interdisciplinary Human-Centered Design Course As A Multiteam System: Perspectives On Cooperation And Information Sharing, Elizabeth S. Fleming, Alexandra E. Coso

Design Thinking Research Symposium

Many design projects, including human-centered design (HCD) projects, incorporate multiple teams cooperating within what is referred to as a Multiteam System (MTS) environment. These teams mutually rely on resources and processes provided by other teams. As an MTS increases in complexity, knowledge is distributed to more individuals. While effectively distributed knowledge increases creativity and productivity, it is also can hinder team effectiveness. Team members may fail to exchange relevant information or to integrate pertinent information into reasoning for design decisions. Our research addresses information sharing among teams and individuals in HCD by examining interactions between and within the MTS (i.e., …

Making Design Pedagogical Content Knowledge Visible Within Design Reviews, Robin Adams, David Radcliffe, Tiago Forin, Mel Chua

Design Thinking Research Symposium

Design pedagogical content knowledge (PCK) is the content-specific specialized teacher knowledge that connects the how (pedagogical knowledge) and what (content knowledge) of teaching design. In this study, we make visible the design PCK in three student design reviews: choreography, undergraduate industrial design, and mechanical engineering. We use cognitive apprenticeship and teaching-as-improvisation frameworks to characterize PK, and design judgment, design task strategies, and process management strategies to characterize CK. We identify and describe four patterns of design PCK: scaffolded articulation, driving for meaning and guidance, breaking the 4^th wall to create a teaching moment, and “suggest don’t tell”. Theoretical implications …