Digital Commons Network^™

Review On Ejector Efficiencies In Various Ejector Systems, Fang Liu

International Refrigeration and Air Conditioning Conference

The ejector efficiencies affect the ejector expansion systems significantly. This paper provides a literature review on ejector efficiency in various ejector systems, such as refrigeration and heat pump systems (transcritical systems and subcritical systems), solar systems, and steam systems. The definitions of ejector efficiency and ejector component efficiencies in literature are summarized. The assumed constant ejector component efficiencies used in ejector modeling, and the empirical correlations of ejector efficiencies derived based on measured data are summarized and compared; the methods of determining energy efficiencies are summarized. The effects of ejector geometries, operation conditions and working fluid characteristics (single phase or …

Void Detection In Dielectric Films Using A Floating Network Of Substrate-Embedded Electrodes, S. H. Taylor, S V. Garimella

CTRC Research Publications

A sensor is developed for simple, in situ characterization of dielectric thermal interface materials (TIMs) at bond line thicknesses less than 100 lm. The working principle is based on the detection of regions of contrasting electric permittivity. An array of long, parallel electrodes is flush-mounted into each opposing substrate face of a narrow gap interface, and exposed to the gap formed between the two surfaces. Electrodes are oriented such that their lengthwise dimension in one substrate runs perpendicular to those in the other. A capacitance measurement taken between opposing electrodes is used to characterize the interface region in the vicinity …

Level-Set Shape Reconstruction Of Binary Permittivity Distributions From Near-Field Focusing Capacitance Measurements, S. H. Taylor, S V. Garimella

CTRC Research Publications

A near-field focusing capacitance sensor consists of an array of long, coplanar electrodes offset by a small interface gap from an identical orthogonal array of electrodes. The sensor may be used to characterize permittivity inhomogeneities in thin dielectric layers. The sensor capacitance measurements represent a tessellated matrix of integral-averaged values describing void content in a series of zones corresponding to the electrode crossing points (junctions) of the sensor. The sensor does not lend itself to computed tomography because the individual capacitance measurements do not represent overlapping regions of sensitivity. An evolving level-set algorithm is proposed to reconstruct a binary permittivity …

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 …

Spectroscopic Analyses Of Factors Affecting Formation And Stability Of I-Motif Dna, Samantha Michelle Reilly

Electronic Theses and Dissertations

The four-stranded i-motif (iM) conformation of DNA has importance to a variety of biochemical systems that include nanomaterials and oncogene regulation. Fundamental studies to understand iM formation and its structure in solution still remain to be done. In this dissertation, we will discuss the use of the fluorescent base analog tC° to determine the structural state of DNA in solution. We will also demonstrate the use of tC° to determine both the hydrodynamic properties and the folding mechanism of an iM. We also determined the loop length dependence on iM formation and stability. Our hydrodynamic studies show that the iM …

Exploration Into The Performance Of Asymmetric D-Ary Heap-Based Algorithms For The Hsa Architecture, Stephen Adams

Electronic Theses and Dissertations

No abstract provided.

Impact Of Thread Scheduling On Modern Gpus, Orevaoghene Addoh

Electronic Theses and Dissertations

The Graphics Processing Unit (GPU) has become a more important component in high-performance computing systems as it accelerates data and compute intensive applications significantly with less cost and power. The GPU achieves high performance by executing massive number of threads in parallel in a SPMD (Single Program Multiple Data) fashion. Threads are grouped into workgroups by programmer and workgroups are then assigned to each compute core on the GPU by hardware. Once assigned, a workgroup is further subgrouped into wavefronts of the fixed number of threads by hardware when executed in a SIMD (Single Instruction Multiple Data) fashion. In this …

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 …

A Semi-Empirical Prediction Model For The Discharge Line Temperature Of Hermetic Compressors, David Myszka, Chen Guan, Andrew Murray, Thomas Hodapp

International Compressor Engineering Conference

Predicting the discharge line temperature (DLT) of air conditioning and refrigeration compressors is important to ensure sufficient lubricant properties and proper performance of components that are positioned in the exhaust stream. Understanding the DLT is also necessary for the design of waste heat recovery systems, which are of increasing interest. However, compressor performance information published by manufacturers does not typically include DLT values. Assumptions made in established thermodynamic models result in only modest correlation between predicted and observed DLT values. Numerous comprehensive DLT prediction models have been developed with excellent accuracy, but require many details of a particular compressor. This …

Fluid-Structure Interaction Of A Reed Type Valve Subjected To Piston Displacement, Olga Estruch, Oriol Lehmkuhl, Joaquim Rigola, Carles David Pérez-Segarra

International Compressor Engineering Conference

In the field of reciprocating compressors, the developing of reed type valves is a challenging task. The understanding of the fluid flow behaviour through the valve reed is essential to improve the valve design. Hence, this work attempts the dynamic simulation of this fluid-structure interaction (FSI) problem, taking into account valve movement due to piston displacement. In this work attends the in-house implemented CFD&HT and moving mesh coupled code TermoFluids [1]. The CFD&HT solver consists of a three-dimensional explicit finite volume fractional-step algorithm formulated in a second-order, conservative and collocated unstructured grid arrangement. The turbulence is modelled by means of …

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 …

Analysis And Classification Of Volcanic Eruptions, Jithamala Caldera, S C. Wirasinghe

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

Among natural disasters, volcanic eruptions are some of the most dangerous. The severity level of the most extreme volcanic eruption for which data is available can be categorized as Catastrophe Type II according to the scale introduced by Wirasinghe, Caldera, Durage, and Ruwanpura, (2013). However, an unusually large eruption of a “super volcano” can even cause a partial or full extinction. Aftermaths of a major eruption, such as climate effects, tsunami, and famine, severely impacts populations. Potential severity levels of volcanic eruptions are studied. A multidimensional scale for volcanic eruptions is investigated. Intensity, fatalities, affected population, impacted region, cost 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 …

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 …

The Influence Of National Culture On Effectiveness Of Safety Trainings During Postdisaster Reconstruction, Kevin R. Grosskopf, Behzad Esmaeili, Amy Javernick-Will

International Institute for Infrastructure Resilience and Reconstruction (I3R2) Conference

Non-English speaking workers constitute a disproportionately high number of workers involved in postdisaster reconstruction. Additionally, the rate of fatality among these workers is higher than the industry average. Research shows this population is more prone to unsafe behaviors in the working environment, conceivably because many of these workers are sent into the field prior to any formalized training. Recent studies show that the native culture of construction workers can impact risk-taking behavior. While numerous researchers have attempted to develop training materials for Hispanic workers, the number of studies that consider the impact of native culture on safety behavior is minimal. …

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 …

Plm In Design And Engineering Education: International Perspectives, E Fielding, J R. Mccardle, B Eynard, Nathan W. Hartman, A Fraser

Computer Graphics Technology Faculty Publications

Technological advances in the last decade have influenced changes in the design and engineering industries on a global scale. Lean and collaborative product development are approaches increasingly adopted by the industry and seen as the core of product lifecycle management. These trends have created the need for new skilled professionals, and universities should adapt their curricula in response. There is an increased need for academia to work with industry in order to meet these challenges. This article reports on the Parametric Technology Corporation Academic Research Symposium held in April 2011. The topics were centred around understanding the essence of product …

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 …

Disciplinary Discourse In Design Reviews: Industrial Design And Mechanical Engineering Courses, Micah Lande, James Oplinger

Design Thinking Research Symposium

An increase in focus on design thinking in the engineering community and design education has led to innovative outcomes. A part of the design thinking education comes from the goals and teaching methods of instructors. From a given dataset of design reviews two different courses were evaluated: industrial design and mechanical engineering. This work analyzes how instructor interactions with individuals or teams fulfill course outcomes. From a discussion of the data analysis it is suggested that industrial designers focus on the passion of the product design while mechanical engineers focus on the functionality and completeness of the design. The ideological …

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 …

Peering Into The Discourse Of Industrial Design Training Through A Sustainability Lens, Norman M. Su, Haodan Tan, Eli Blevis

Design Thinking Research Symposium

Now well established in HCI, the lens of sustainability may be applied to educational practices in industrial design and interaction design. By sustainability, we mean to include notions of mitigation of the environmental effects of climate change. In this paper, we present an analysis of student projects in a junior and senior industrial design class dataset. Drawing from discourse analysis, we examine how the industrial design classroom serves as a space to socially construct the philosophies and goals inherent in “good” design. We then examine how the lens of sustainability is implicated into the industrial design “way” as espoused by …

Experiences Of Informed Learning In The Undergraduate Classroom, Clarence Maybee

Libraries Faculty and Staff Scholarship and Research

The same thing can be experienced in a variety of ways. For example, think of a time that you and a friend read the same book, but each got something quite different out of it. Essentially you experienced different aspects of the book. Applying this to higher education, we cannot assume that all students are experiencing their coursework in the same way. In fact, a number of studies reveal that this is not the case. Learning occurs when students begin to experience the thing being learned about in a new way. Learning designs that teach undergraduates to use information require …

Study Of User Search Activities With Two Discovery Tools At An Academic Library, Xi Niu, Tao Zhang, Hsin-Liang Chen

Libraries Faculty and Staff Scholarship and Research

The goal of this study was to investigate and compare user search activities of two discovery tools at an academic library. The implementation of a new discovery tool (Primo by Ex Libris) to replace an existing system (VuFind) provided a unique opportunity to collect transaction logs of both systems and examine user search behavior in an empirical test. Results from a transaction log analysis and a user study of this study have contributed to the understanding of users’ search behavior and their preferences and perceptions of the two systems. We find both commonalities and differences between VuFind and Primo for …

Data Driven Collection Development At Mathematical Sciences Library Of Purdue University, Nastasha E. Johnson

Libraries Faculty and Staff Presentations

No abstract provided.

Influences Of Feedback Interventions On Student Concept Generation And Development Practices, Seda Yilmaz, Shanna Daly

Design Thinking Research Symposium

Design teaching in many disciplines relies on feedback as a primary way for students and instructors to communicate. Our work focused on identifying feedback types in three different design disciplines (dance choreography, industrial design, and mechanical engineering) and analyzing how those feedback types encouraged students to take convergent or divergent paths with their design ideas. We then compared feedback types and encouragement of convergence or divergence across the three disciplines. Our findings showed many common types of feedback used across the three disciplines, regardless of variance in context and expectations. However, the findings also revealed a high frequency of feedback …

Three Studio Critiquing Cultures: Fun Follows Function Or Function Follows Fun?, Gabriela Goldschmidt, Hernan Casakin, Yonni Avidan, Ori Ronen

Design Thinking Research Symposium

For the longest time, design was an activity with no distinction among disciplines. Over time, separate design disciplines had formed their own cultures and their own educational practices. In this paper, we use data from a limited set of design reviews along with a literature survey to conduct a comparative analysis of contemporary reviewing and critiquing cultures in architecture, industrial design and mechanical engineering. We point out differences and communalities, and conclude with a list of the lessons the three disciplines can learn from one another regarding reviewing in the classroom. We dwell especially on one issue that currently differentiates …

Strain Modulations As A Mechanism To Reduce Stress Relaxation In Laryngeal Tissues, Eric J. Hunter, Thomas Siegmund, Roger W. Chan

School of Mechanical Engineering Faculty Publications

Vocal fold tissues in animal and human species undergo deformation processes at several types of loading rates: a slow strain involved in vocal fold posturing (on the order of 1 Hz or so), cyclic and faster posturing often found in speech tasks or vocal embellishment (1–10 Hz), and shear strain associated with vocal fold vibration during phonation (100 Hz and higher). Relevant to these deformation patterns are the viscous properties of laryngeal tissues, which exhibit non-linear stress relaxation and recovery. In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects …

A New Dynamic Heat Exchanger Model With Frosting And Defrosting, Hongtao Qiao, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

In this paper, a dynamic heat exchanger model that unifies the frosting and defrosting analyses is presented. A novel scheme is proposed to solve the air flow redistribution due to non-uniform frost blockage. Unlike the existing defrost models which separate analysis for tubes and fins, the proposed defrost model unifies the analysis to maintain model consistency. The first-principles based frost and defrost models developed in this research allow for a more realistic assessment of the heat pump systems and greatly facilitate the design of controls. Utilizing the developed models, the transient behavior of a flash tank vapor injection heat pump …

Comparing Cop Optimization With Maximizing The Coefficient Of System Performance For Refrigeration Systems In Supermarkets, Martin R. Braun, Stephen B. M. Beck, Ha?Im Altan

International Refrigeration and Air Conditioning Conference

In recent years the energy usage of supermarkets, in particular that of their refrigeration systems, has been investigated using a variety of approaches, such as floating pressure set points and integrating the heating and refrigeration systems. Something which has not yet attracted much attention is the energy consumption of the dry condenser fans in refrigeration systems. This is surprising as it has been shown for comparable installations that including the energy consumption of these fans when optimizing the system efficiency was beneficial. To address this deficit, _COP_ maximization has been compared to optimizing the Coefficient of System Performance (_COSP_). The …