Engineering Commons^™

Flavour Chemicals In A Sample Of Non-Cigarette Tobacco Products Without Explicit Flavour Names Sold In New York City In 2015, Shannon M. Farley, Kevin R.J. Schroth, Victoria Grimshaw, Wentai Luo, Julia Lynn Degagne, Peyton A. Tierney, Kilsun Kim, James F. Pankow

Chemistry Faculty Publications and Presentations

Background Youth who experiment with tobacco often start with flavoured products. In New York City (NYC), local law restricts sales of all tobacco products with ‘characterising flavours’ except for ‘tobacco, menthol, mint and wintergreen’. Enforcement is based on packaging: explicit use of a flavour name (eg, ‘strawberry’) or image depicting a flavour (eg, a fruit) is presumptive evidence that a product is flavoured and therefore prohibited. However, a tobacco product may contain significant levels of added flavour chemicals even when the label does not explicitly use a flavour name.

Methods Sixteen tobacco products were purchased within NYC in 2015 that …

Head Waves In Ocean Acoustic Ambient Noise: Measurements And Modeling, Martin Siderius, Jie Li, Peter Gerstoft

Electrical and Computer Engineering Faculty Publications and Presentations

Seismic interferometry recovers the Green’s function between two receivers by cross-correlating the field measured from sources that surround the receivers. In the seismic literature, it has been widely reported that this processing can produce artifacts in the Green’s function estimate called “spurious multiples” or the “virtual refracted wave.” The spurious multiples are attributed to the head wave and its multiples and travels in the seabed. The head wave phenomenon is shown to be observable from both controlled active sources and from ocean ambient noise and for both vertical and horizontal arrays. The processing used is a generalization of the passive …

Exploring The Determinants Of Vulnerable Road Users’ Crash Severity In State Roads, Álvaro Caviedes

PSU Transportation Seminars

Part of the Student Presentations from TRB

Pedestrians and bicyclists are the most vulnerable road users and suffer the most severe consequences when crashes take place. An extensive literature is available for crash severity in terms of driver safety, but fewer studies have explored non-motorized users’ crash severity. Furthermore, most research efforts have examined pedestrian and bicyclist crash severity in urban areas. This study focuses on state roads (mostly outside major urban areas) and aims to identify contributing risk factors of fatal and severe crashes involving pedestrians and bicyclists in state roads. The results seem to suggest that besides improvements …

Silicon Compilation And Test For Dataflow Implementations In Gasp And Click, Swetha Mettala Gilla

Dissertations and Theses

Many modern computer systems are distributed over space. Well-known examples are the Internet of Things and IBM's TrueNorth for deep learning applications. At the Asynchronous Research Center (ARC) at Portland State University we build distributed hardware systems using self-timed computation and delay-insensitive communication. Where appropriate, self-timed hardware operations can reduce average and peak power, energy, latency, and electromagnetic interference. Alternatively, self-timed operations can increase throughput, tolerance to delay variations, scalability, and manufacturability.

The design of complex hardware systems requires design automation and support for test, debug, and product characterization.

This thesis focuses on design compilation and test support for dataflow …

Stress Analysis Of Embedded Devices Under Thermal Cycling, Sadhana Radhakrishnan

Dissertations and Theses

Embedded active and passive devices has been increasingly used by in order to integrate more functions inside the same or smaller size device and to meet the need for better electrical performance of the component assemblies.

Solder joints have been used in the electronic industry as both structural and electrical interconnections between electronic packages and printed circuit boards (PCB). When solder joints are under thermal cyclic loading, mismatch in coefficients of thermal expansion (CTE) between the printed circuit boards and the solder balls creates thermal strains and stresses on the joints, which may finally result in cracking. Consequently, the mechanical …

Development Of A Design Guideline For Bridge Pile Foundations Subjected To Liquefaction Induced Lateral Spreading, Jonathan A. Nasr

Dissertations and Theses

Effective-stress nonlinear dynamic analyses (NDA) were performed for piles in liquefiable sloped ground to assess how inertia and liquefaction-induced lateral spreading combine in long-duration vs. short-duration earthquakes. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of earthquake durations. The NDA results were used to evaluate the accuracy of the equivalent static analysis (ESA) recommended by Caltrans/ODOT for estimating pile demands. Finally, the NDA results were used to develop new ESA methods to combine inertial and lateral spreading loads for estimating elastic and inelastic pile demands.

The NDA results showed that pile …

Mechanisms And Identification Of Unsteady Separation Development And Remediation, Matthew Scott Melius

Dissertations and Theses

Unsteady flow separation represents a highly complex and important area of study within fluid mechanics. The extent of separation and specific time scales over which it occurs are not fully understood and has significant consequences in numerous industrial applications such as helicopters, jet engines, hydroelectric turbines and wind turbines. A direct consequence of unsteady separation is the erratic movement of the separation point which causes highly dynamic and unpredictable loads on an airfoil. Current computational models underestimate the aerodynamic loads due to the inaccurate prediction of the emergence and severity of unsteady flow separation especially in response to a sudden …

Minimizing Commute Distance For Small Groups: A Linear Programming Approach, Kevin Payne, Kritika Kumari, Levi Huddleston, Rabi Hassan

Engineering and Technology Management Student Projects

This paper aims to minimize total drive time between members and their respective group leader. Given a limit on group size and days available, how can a formulation of a group occur such that the sum of the total drive time is minimized. To accomplish this task a Linear Program (LP) is implemented that includes three sets of binary decisions variables summing to 4100 variables and a variety of constraints summing between 4200 and 4341 depending on the constraints enforced. For 200 members and 15 leaders the minimized average commuting time was found to be between 4.99 and 5.36 minutes …

Shift Scheduling Optimization For Psu Library, Aayushi Gupta, Anju Babu, Lipishree Vrushabhendra, Shivani Purwar, Shravankumar Doosa

Engineering and Technology Management Student Projects

Scheduling is important in any business as it creates an order and flow ensuring that all the tasks are covered at appropriate times. According to experts, scheduling determines the economics of a job, the quality of the team, and the skill-building and motivation of professionals doing the work. Therefore, it is essential to have optimized staff schedules to meet the requirements of staff availability, tasks coverage, shift equity and staff preferences. Though staff scheduling is of such prime importance, it is mostly implemented in traditional ways of manually creating spreadsheets and web calendars proving to be laborious and often leaving …

Exploring High-Resolution Data Obtained From Asc/3 Controller Of Intersection Se Division St & Se 122nd Ave, Portland, Oregon, Naowar Al-Abbas

Civil and Environmental Engineering Master's Project Reports

High-resolution data obtained from ASC/3 controllers can be used to create a variety of performance measures, helping engineers and professionals in monitoring intersection performance, identifying issues, and making proper improvements. These measures concern the intersection quality of the progression, capacity, and non-vehicular operations (e.g. pedestrian crossings). In this report, we explored high-resolution data obtained from the intersection of SE Division Street and 122nd Avenue. This intersection had some safety concerns as it is considered one of most dangerous intersections in Portland, Oregon. Thus, the first variable we examined from the data was pedestrian wait time when a cross request is …

Inertial And Liquefaction-Induced Kinematic Demands On A Pile-Supported Wharf: Physical Modeling, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough

Civil and Environmental Engineering Faculty Publications and Presentations

Results of a centrifuge test on a pile-supported wharf were used to investigate the time-, depth-, and row-dependent nature of kinematic and inertial loading on wharf piles in sloping rockfill. P-y models were calibrated against recorded bending moments in different piles and different depths. It was found that full kinematic demands and full superstructure inertia should be combined to estimate bending moments at pile head and shallow depths (less than 10 diameters below the ground surface). On the contrary, it was found that applying full kinematic demands alone was adequate to estimate pile bending moments at large depths (greater than …

The Effects Of Long-Duration Subduction Earthquakes On Inelastic Behavior Of Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Jonathan Nasr, Arash Khosravifar

Civil and Environmental Engineering Faculty Publications and Presentations

Effective-stress nonlinear dynamic analyses (NDA) were performed for a large-diameter reinforced concrete (RC) pile in multi-layered liquefiable sloped ground. The objective was to assess the effects of earthquake duration on the combination of inertia and liquefaction-induced lateral spreading. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of motion durations. The NDA results showed that the pile head displacements increased under liquefied conditions, compared to nonliquefied conditions, due to liquefaction-induced lateral spreading. The NDA results were used to develop a displacement-based equivalent static analysis (ESA) method that combines inertial and lateral spreading …

Drone Deliveries Logistics, Efficiency, Safety And Last Mile Trade-Offs, Miguel A. Figliozzi, Chad Tucker, Polina Polikakhina

Civil and Environmental Engineering Faculty Publications and Presentations

Unmanned aerial vehicles (UAV) or drone last mile deliveries are receiving a lot of attention from startups and big companies like Google, Amazon, and UPS. Around the world there are already examples of successful small scale delivery operations utilizing drones. Despite all the hype and excitement around this topic, there is surprisingly little research done on understanding the capabilities and technical tradeoffs among drones that are currently available in the market. The goal of this paper is to survey currently available multicopter drones and analyze them in terms of their potential for last mile and last yard deliveries. Novel data …

Hydro-Climatological Summer Trends In The Continental United States, Naya Mairena Flores

REU Final Reports

We investigated trends in air temperature, stream temperature and discharge for rivers across the continental United States from the summer months of 1996 to 2016. Using GAGES II from USGS and PRISM and programming language R we analyzed specific hydrological trends in Mann-Kendall’s tests. After collecting the slope values whether they were negative or positive and the P-Values, the significance of that slope, we mapped slopes of trends in GIS. Stream temperature increased 12% of stations across the summer, while air temperature increased 22% of stations, and discharge decreased 15% of stations, respectively. Seven day moving average of daily maximum …

Deciphering The Rules Of Cell-To-Cell Coupling By Molecular Modeling And Simulation, Linda D. Lee

REU Final Reports

Intercellular communication is vital for quick adjustments and maintenance for cell function and development. Gap junctions are membranes channel proteins that enable this direct communication between adjacent cells throughout the body. The compatibility of connexins (Cx), which make up a gap junction, determines whether a gap junction can form. Though many studies show which connexins are compatible, the molecular basis is not known (Bai & Wang, 2014). Through computational modeling, we identify the residues that energetically contribute most favorably at the docking interface of homotypic and heterotypic combinations of Cx43, Cx46, and Cx50 gap junctions. However, due to instability of …

Modified Design Procedures For Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Arash Khosravifar, Jonathan Nasr

Civil and Environmental Engineering Faculty Publications and Presentations

Effective-stress nonlinear dynamic analyses (NDA) were performed for piles in the liquefiable sloped ground to assess how inertia and liquefaction-induced lateral spreading combine in long- and short-duration motions. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of durations and amplitudes. The NDA results showed that the pile demands increased due to (a) longer duration shakings, and (b) liquefaction-induced lateral spreading compared to nonliquefied conditions. The NDA results were used to evaluate the accuracy of the equivalent static analysis (ESA) recommended by Caltrans/ODOT for estimating pile demands. Finally, the NDA results were …

Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena

REU Final Reports

The Intergovernmental Panel on Climate Change (IPCC) has various Global Climate Models (GCM). One of them, models three greenhouse gases. The increasing amount of greenhouse gases are just a fraction of factors that fuel global climate change. According to the IPCC 2014, climate related extremes such as heatwaves are likely to occur more regularly and are likely to increase in duration. Since 1979, there has been over 9000 deaths that occurred from heat-related incidents in the United States (U.S. Environmental Protection Agency, 2016). Which brings attention to population groups who are exposed to hot temperatures on a frequent basis due …

The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed

REU Final Reports

Plastic particles contaminating the world’s oceans and accumulating in oceanic gyres has become a ubiquitous problem and the solution involving how to clean up the debris efficiently has still not been found. One particular issue is understanding where the greatest densities of debris may be. It is known that floating trash will tend to accumulate in large circular systems of ocean water called gyres, however these areas span thousands of miles of ocean. The present study aims to understand the transport of anisotropic particles in conditions similar to an oceanic environment using experimental methods in an effort to better predict …

Water Quality Factor Prediction Using Supervised Machine Learning, Kathleen Joslyn

REU Final Reports

The objective of this research is to explore prediction accuracy of water quality factors, with techniques and algorithms in machine learning consisting of a variation of support vector machines - Support Vector Regression (SVR) and the gradient boosting algorithm Extreme Gradient Boosting (XGBoost). Both the XGBoost and SVR algorithms were used to predict nine different factors with success rates ranging from 79% to 99%. Parameters of these algorithms were also explored to test the prediction accuracy levels of individual water quality factors. These parameters included normalizing the data, filling missing data points, and training and testing on a large set …

Pathways For Mitigating Thermal Losses In Solar Photovoltaics, Rodolphe Vaillon, Oliver Dupre, Raúl Bayoán Cal, Marc Calaf

Mechanical and Materials Engineering Faculty Publications and Presentations

To improve the performance of solar photovoltaic devices one should mitigate three types of losses: optical, electrical and thermal. However, further reducing the optical and electrical losses in modern photovoltaic devices is becoming increasingly costly. Therefore, there is a rising interest in minimizing the thermal losses. These correspond to the reduction in electrical power output resultant of working at temperatures above 25 °C and the associated accelerated aging. Here, we quantify the impact of all possible strategies to mitigate thermal losses in the case of the mainstream crystalline silicon technology. Results indicate that ensuring a minimum level of conductive/convective cooling …

Technology Foresight: A Bibliometric Analysis To Identify Leading And Emerging Methods, Elizabeth Gibson, Tugrul U. Daim, Edwin Garces, Marina Dabic

Engineering and Technology Management Faculty Publications and Presentations

Foresight studies provide essential information used by the government, industry and academia for technology planning and knowledge expansion. They are complicated, resource-intensive, and quite expensive. The approach, methods, and techniques must be carefully identified and selected. Despite the global importance of foresight activities, there are no frameworks to help one develop and plan a proper foresight study. This paper begins Keywords: technology foresight; strategic foresight; adaptive foresight; Social Network Analysis (SNA); bibliometric tools; data mining; text mining. to close this gap by analyzing and comparing different schools of thought and updating the literature with the most current tools and methods. …

Mechanisms Controlling Copper Transport In Natural Soils, Julie A. Luisi

Civil and Environmental Engineering Master's Project Reports

Biosolids are used as amendments to agricultural soils and can be a source of trace metals. It is unknown if these land-applied trace metals travel through the soil column to the water table. This study aims to determine the transport behavior of copper in natural soils, including 'aged' soils, commercial agricultural soils that have had multiple years of biosolids applications. Using acid digests and Darcy column apparatus it was determined that factors such as pH, soil composition, especially organic matter content, and the presence of other trace metals influence copper’s complex transport behavior in these soils. Natural soil appears to …

Reflections On Teaching System Dynamics Modeling To Secondary School Students For Over 20 Years, Diana Fisher

Complex Systems Faculty Publications and Presentations

This paper contains the description of a successful system dynamics (SD) modeling approach used for almost a quarter-century in secondary schools, both in algebra classes and in a year-long SD modeling course. Secondary school students have demonstrated an ability to build original models from the news, write technical papers explaining their models, and present a newfound understanding of dynamic feedback behavior to an audience. The educational learning theory and instructional methods used for both the algebra and modeling courses are detailed, with examples. Successful student SD modeling experiences suggest the SD approach can expand the sophistication of topics that secondary …

Turbulence, Entrainment And Low-Order Description Of A Transitional Variable-Density Jet, Bianca Viggiano, Tamara S. Dib, N. Ali, L. G. Mastin, Raúl Bayoán Cal, S. A. Solovitz

Mechanical and Materials Engineering Faculty Publications and Presentations

Geophysical flows occur over a large range of scales, with Reynolds numbers and Richardson numbers varying over several orders of magnitude. For this study, jets of different densities were ejected vertically into a large ambient region, considering conditions relevant to some geophysical phenomena. Using particle image velocimetry, the velocity fields were measured for three different gases exhausting into air – specifically helium, air and argon. Measurements focused on both the jet core and the entrained ambient. Experiments considered relatively low Reynolds numbers from approximately 1500 to 10 000 with Richardson numbers near 0.001 in magnitude. These included a variety of …

Transportation Impacts Of Affordable Housing: Informing Development Review With Travel Behavior Analysis, Amanda Howell, Kristina Marie Currans, Steven R. Gehrke, Gregory Norton, Kelly J. Clifton

Civil and Environmental Engineering Faculty Publications and Presentations

Planning for affordable housing is challenged by development policies that assess transportation impacts based on methodologies that often do not distinguish between the travel patterns of residents of market-rate housing and those living in affordable units. Given the public goals of providing affordable housing in areas with good accessibility and transportation options, there is a need to reduce unnecessary costs imposed by the potential overestimation of automobile travel and its associated impacts. Thus, the primary objective of this paper is to examine and quantify the influences of urban characteristics, residential housing type, and income on metrics commonly used to assess …

Generating Adversarial Attacks For Sparse Neural Networks, Jack H. Chen, Walt Woods

Maseeh Summer Undergraduate Research Experience

Neural networks provide state-of-the-art accuracy for image classification tasks. However traditional networks are highly susceptible to imperceivable perturbations to their inputs known as adversarial attacks that drastically change the resulting output. The magnitude of these perturbations can be measured as Mean Squared Error (MSE). We use genetic algorithms to produce black-box adversarial attacks and examine MSE on state-of-the-art networks. This method generates an attack that converts 90% confidence on a correct class to 50% confidence of a targeted, incorrect class after 2000 epochs. We will generate and examine attacks and their MSE against several sparse neural networks. We theorize that …

Early Emerging Pathogen Detection, Mackenzie Wangenstein

Maseeh Summer Undergraduate Research Experience

A supervised learning technique was employed to identify emerging pathogen species. Portland State University has partnered with the University of New Mexico to take encodings of unknown pathogen molecular structures to determine emerging species.

A Time-Efficient Cmos-Memristive Programmable Circuit Realizing Logic Functions In Generalized And-Xor Structures, Muayad Aljafar, Marek Perkowski, John M. Acken, Robin Tan

Electrical and Computer Engineering Faculty Publications and Presentations

This paper describes a CMOS-memristive Programmable Logic Device connected to CMOS XOR gates (mPLD-XOR) for realizing multi-output functions well-suited for two-level {NAND, AND, NOR, OR}-XOR based design. This structure is a generalized form of AND-XOR logic where any combination of NAND, AND, NOR, OR, and literals can replace the AND level. For mPLD-XOR, the computational delay, which is measured as the number of clock cycles, equals the maximum number of inputs to any output XOR gate of a function assuming that the number of XOR gates is large enough to calculate the outputs of the function simultaneously. The input levels …

Terahertz Imaging Of Thin Film Layers With Matched Field Processing, Scott Schecklman, Lisa M. Zurk

Electrical and Computer Engineering Faculty Publications and Presentations

Terahertz (THz) time of flight (TOF) tomography systems offer a new measurement modality for non-destructive evaluation (NDE) of the subsurface layers of protective coatings and/or laminated composite materials for industrial, security and biomedical applications. However, for thin film samples, the time-of-flight within a layer is less than the duration of the THz pulse and consequently there is insufficient range resolution for NDE of the sample under test. In this paper, matched field processing (MFP) techniques are applied to thickness estimation in THz TOF tomography applications, and these methods are demonstrated by using measured THz spectra to estimate the the thicknesses …

Subspace Clustering Using Ensembles Of K-Subspaces, John Lipor, David Hong, Yan Shuo Tan, Laura Balzano

Electrical and Computer Engineering Faculty Publications and Presentations

Subspace clustering is the unsupervised grouping of points lying near a union of low-dimensional linear subspaces. Algorithms based directly on geometric properties of such data tend to either provide poor empirical performance, lack theoretical guarantees, or depend heavily on their initialization. We present a novel geometric approach to the subspace clustering problem that leverages ensembles of the K-subspaces (KSS) algorithm via the evidence accumulation clustering framework. Our algorithm, referred to as ensemble K-subspaces (EKSS), forms a co-association matrix whose (i,j)th entry is the number of times points i and j are clustered together by several runs of KSS with random …