Digital Commons Network^™

Impact Of Pressure Drop Oscillations On Surface Temperature And Critical Heat Flux During Flow Boiling In A Microchannel, M.D. Clark, J.A. Weibel, S.V. Garimella

CTRC Research Publications

Flow boiling in microchannel heat sinks is capable of providing the high-heat-flux dissipation required for thermal management of next-generation wide bandgap power electronics at low pumping power and uniform surface temperatures. One of the primary issues preventing implementation of these technologies is the presence of flow boiling instabilities, which may reduce the heat transfer performance. However, the effect of individual instabilities, such as the parallel channel instability or pressure drop oscillations, on the overall heat transfer coefficient and critical heat flux in microchannel heat sinks has not been fully quantified. The primary cause of these dynamic flow boiling instabilities is …

Human Body–Electrode Interfaces For Wide-Frequency Sensing And Communication: A Review, Kurian Polachan, Baibhab Chatterjee, Scott Weigand, Shreyas Sen

Department of Electrical and Computer Engineering Faculty Publications

Several on-body sensing and communication applications use electrodes in contact with the human body. Body–electrode interfaces in these cases act as a transducer, converting ionic current in the body to electronic current in the sensing and communication circuits and vice versa. An ideal body–electrode interface should have the characteristics of an electrical short, i.e., the transfer of ionic currents and electronic currents across the interface should happen without any hindrance. However, practical body–electrode interfaces often have definite impedances and potentials that hinder the free flow of currents, affecting the application’s performance. Minimizing the impact of body–electrode interfaces on the application’s …

Common-Mode Capacitance Of Bus-Bar-Based Common-Mode Inductors, Harshita Singh, Scott D. Sudhoff, Robert R. Swanson

Department of Electrical and Computer Engineering Faculty Publications

Prediction of the common-mode self-capacitance of common-mode inductors is essential to their design in order to ensure effective operation over the frequency range of interest. This paper presents a model for the calculation of common-mode capacitance of a bus-bar-based common-mode inductor. An equivalent circuit of the inductor that accounts for high-frequency effects such as eddy currents in nanocrystalline cores is also set forth. The predicted and measured capacitances are compared for three such inductors.

An Experimental Investigation Of The Effect Of Thermal Coupling Between Parallel Microchannels Undergoing Boiling On The Ledinegg Instability-Induced Flow Maldistribution, A. Miglani, J. A. Weibel, S V. Garimella

CTRC Research Publications

Two-phase flow boiling is susceptible to the Ledinegg instability, which can result in non-uniform flow distribution between parallel channels and thereby adversely impact the heat transfer performance. This study experimentally assesses the effect of thermal coupling between parallel microchannels on the flow maldistribution caused by the Ledinegg instability and compares the results to our prior theoretical predictions. A system with two parallel microchannels is investigated using water as the working fluid. The channels are hydrodynamically connected via common inlet/outlet plenums and supplied with a constant total flow rate. The channels are uniformly subjected to the same input power (which is …

Topology Optimization Of Microchannel Heat Sinks Using A Homogenization Approach, S. Ozguc, L. Pan, J. A. Weibel

CTRC Research Publications

Topology optimization for heat sink devices typically relies on penalization methods to ensure the fi- nal designs are composed of strictly solid or open regions. In this work, we formulate a homogenization approach wherein the partial densities are physically represented as porous microstructures. This formu- lation allows design of thermal management components that have sub-grid features and leverages ad- ditive manufacturing techniques that can produce such partially porous regions within the build volume. Topology optimization of a liquid-cooled microchannel heat sink is presented for a hotspot over a uniform background heat input. The partial densities are represented as arrays of …

The Role Of Dynamic Wetting Behavior During Bubble Growth And Departure From A Solid Surface, Taylor P. Allred, Justin A. Weibel, S V. Garimella

CTRC Research Publications

Surface wettability is known to have a major influence on the ebullition characteristics of a bubble growing from a solid surface. Yet, simplistic static characterization of the wetting behavior is still relied upon to indicate performance characteristics during boiling. In this study, a theoretical framework is developed for the wetting and dewetting processes occurring during bubble growth based upon the dynamic contact angles. This framework is incorporated into adiabatic volume-of-fluid simulations to capture the influence of the surface wettability on contact line and contact angle dynamics during bubble growth and departure. The simulations span a large range of dynamic wetting …

Measurement Of Flow Maldistribution Induced By The Ledinegg Instability During Boiling In Thermally Isolated Parallel Microchannels, A. Miglani, J. A. Weibel, S V. Garimella

CTRC Research Publications

Flow boiling in a network of heated parallel channels is prone to instabilities that can cause uneven flow distribution, thereby degrading the heat transfer performance of the system and limiting predictability. This study experimentally investigates flow maldistribution between two parallel microchannels that arises due to the Ledinegg instability. The channels are heated uniformly and are thermally isolated from each other, such that both channels are subjected to the same input power regardless of the flow distribution. The channels are hydrodynamically connected in parallel and deionized water is delivered at a constant total flow rate shared by both channels. Direct measurements …

A Semi-Empirical Model For Thermal Resistance And Dryout During Boiling In Thin Porous Evaporators Fed By Capillary Action, S. Sudhakar, J.A. Weibel, S.V. Garimella

CTRC Research Publications

Two-phase passive heat transport devices such as vapor chambers, loop heat pipes, and capillary pumped loops utilize porous evaporators for phase change and to drive fluid transport. Nucleate boiling can occur within such capillary-fed porous evaporators, especially under high-heat-flux operation, as has been visually observed in various experimental studies in the literature. However, prior modeling efforts have typically only considered single-phase flow of liquid through a completely saturated porous medium for characterizing the dryout limit and thermal performance. The present work offers a new semi-empirical model for prediction of thermal resistance and dryout during boiling in capillary-fed evaporators. Thermal conduction …

Thermal And Mechanical Characterization Of High-Performance Polymer Fabrics For Applications In Wearable Devices, A. A. Candadai, E. J. Nadler, J. S. Burke, J. A. Weibel, A. M. Marconnet

CTRC Research Publications

With advances in fexible and wearable device technology, thermal regulation will become increasingly important. Fabrics and substrates used for such applications will be required to efectively spread any heat generated in the devices to ensure user comfort and safety, while also preventing overheating of the electronic components. Commercial fabrics consisting of ultra-high molecular weight polyethylene (UHMW-PE) fbers are currently used in personal body armor and sports gear owing to their high strength, durability, and abrasion resistance. In addition to superior mechanical properties, UHMW-PE fbers exhibit very high axial thermal conductivity due to a high degree of polymer chain orientation. However, …

Effective Anisotropic Properties-Based Representation Of Vapor Chambers, K. Baraya, J. A. Weibel, S V. Garimella

CTRC Research Publications

An easy-to-use representation of vapor chambers is developed in terms of effective anisotropic properties. This approach enables accurate simulation of the vapor chamber represented as a solid conduction block by assigning appropriate values to its effective density, specific heat, in-plane thermal conductivity, and through-plane thermal conductance. These effective properties are formulated such that the vapor chamber operation in terms of steady-state and transient thermal responses matches a full, physical simulation of phase change and energy transport in the vapor core; they are intrinsic properties that can be applied independently of the boundary conditions and heat input.

Machine-Learning Assisted Optimization Strategies For Phase Change Materials Embedded Within Electronic Packages, M. Bhatasana, A. M. Marconnet

CTRC Research Publications

No abstract provided.

Investigation Of Boiling Behaviors In Vapor Chambers In Response To Transient Heat Input Profiles, S. Sudhakar, S.N. Joshi, J.A. Weibel

CTRC Research Publications

Vapor chambers are being increasingly utilized as passive heat spreaders in various high-power density thermal management architectures. Particularly, in applications involving power electronics packaging, there is a need to understand and predict thermal performance of vapor chambers under different transient heat loads. It is known that boiling could occur in the wick structure of a vapor chamber at the location of heat input if sufficiently high heat fluxes are directly imposed on the chamber wall. Prior experimental studies that characterize the steady state thermal resistance of vapor chambers versus input power can only identify the behavior before and after the …

Asymmetric Solidification During Droplet Freezing In The Presence Of A Neighboring Droplet, J. E. Castillo, Y. Huang, Z. Pan, J. A. Weibel

CTRC Research Publications

A supercooled liquid droplet that freezes on a cold substrate interacts with the local surroundings through heat and mass exchange. Heat loss occurs to the substrate via conduction and at the droplet interface via evaporative cooling, diffusion, and convection. In a group of many droplets, these interac- tions are believed to be responsible for inter-droplet frost propagation and the evaporation of supercooled neighboring droplets. Furthermore, interactions between a standalone freezing droplet and its surround- ings can lead to the formation of condensation halos and asymmetric solidification induced by exter- nal flows. This paper investigates droplet-to-droplet interactions via heat and mass …

Quantifying The Pathways Of Latent Heat Dissipation During Droplet Freezing On Cooled Substrates, J. E. Castillo, Y. Huang, Z. Pan, J. A. Weibel

CTRC Research Publications

When a liquid droplet freezes on a cooled substrate, the portion of latent heat released by ice formation that is not immediately absorbed by the supercooled liquid droplet is transferred to the solid substrate below the droplet and the surrounding air. It is important to quantify heat dissipation through these two pathways because they govern the propagation of frost between multiple droplets. In this paper, infrared (IR) thermography measurements of the surface of a freezing droplet are used to quantify the fraction of latent heat released to the substrate and the ambient air. These IR measurements also show that the …

Cascaded Multi-Core Vapor Chambers For Intra-Package Spreading Of High Power, Heterogeneous Heat Loads,, S. Bandyopadhyay, A. M. Marconnet, Justin Weibel

CTRC Research Publications

A cascaded multi-core vapor chamber (CMVC) is designed for dissipating heat from high-flux hotspots simultaneously with a high-total-power background. Current thermal management strategies rely on spreading high local heat fluxes by conduction in the lid of electronics packages. Embedding vapor chambers within the lid is an attractive option to directly address intra-package hotspots. We investigate the design of intra-lid vapor chambers, for a generic device having a total heat load of 476 W having a background heat flux of 0.75 W/mm², with hotspots of 8 W/mm² over a 1 mm² area. A conventional vapor chamber design, …

Positive Deviants For Medication Therapy Management: A Mixed-Methods Comparative Case Study Of Community Pharmacy Practices, Omolola A. Adeoye-Olatunde, Leslie M. Lake, Celena Strohmier, Amanda K. Gourley, Ashli R. Ray, Alan J. Zillich, Margie E. Snyder

Department of Pharmacy Practice Faculty Publications

Background

To optimize medication use in older adults, the Centers for Medicare & Medicaid Services (CMS) launched Medication Therapy Management (MTM) services as part of Medicare Part D policy; however, strategies for achieving high quality MTM outcomes are not well understood.

Objective

The objective of this study was to generate hypotheses for strategies contributing to community pharmacies’ high performance on policy-relevant MTM quality measures.

Methods

This mixed-methods comparative case study was guided by the Positive Deviance approach and Chronic Care Model. The study population consisted of pharmacy staff employed by a Midwestern division of a national supermarket-community pharmacy chain. Data …

A User-Centered Evaluation Of Medication Therapy Management Alerts For Community Pharmacists: Recommendations To Improve Usability And Usefulness, Margie Snyder, Omolola A. Adeoye-Olatunde, Stephanie A. Gernant, Julie Diiulio, Heather A. Jaynes, William R. Doucette, Alissa L. Russ-Jara

Department of Pharmacy Practice Faculty Publications

Background

Community pharmacists provide comprehensive medication reviews (CMRs) through pharmacy contracts with medication therapy management (MTM) vendors. These CMRs are documented in the vendors' web-based MTM software platforms, which often integrate alerts to assist pharmacists in the detection of medication therapy problems. Understanding pharmacists’ experiences with MTM alerts is critical to optimizing alert design for patient care.

Objectives

The objectives of this study were to 1) assess the usability and usefulness of MTM alerts for MTM vendor-contracted community pharmacists and 2) generate recommendations for improving MTM alerts for use by community pharmacists.

Methods

This was a convergent, parallel mixed-methods evaluation …

A Mixed-Methods Study Of Pharmacy Instructors' Early Experiences With A Teaching Electronic Medical Record, Omolola A. Adeoye-Olatunde, Olga O. Vlashyn, Kimberly Plake, Jamie L. Woodyard, Zachary A. Weber, Debra K. Litzelman, Alissa L. Russ-Jara

Department of Pharmacy Practice Faculty Publications

Introduction

As use of electronic medical records (EMRs) increases in healthcare, multiple accreditation organizations recommend training future clinicians on EMRs as part of the academic curriculum. Therefore, some pharmacy programs now utilize an academic EMR. Our objective was to examine pharmacy instructors' early experiences with a commercially available teaching EMR (tEMR) in order to identify current and future priorities along with benefits and barriers to academic EMR use in pharmacy education.

Methods

We conducted semi-structured interviews and a web-based survey with pharmacy instructors. Interview and survey data analyses consisted of hybrid inductive/deductive approaches to coding data and descriptive statistics, …

Research And Scholarly Methods: Semi-Structured Interviews, Omolola A. Adeoye-Olatunde, Nicole Olenik

Department of Pharmacy Practice Faculty Publications

The popularity and value of qualitative research has increasingly been recognized in health and pharmacy services research. Although there is certainly an appropriate place in qualitative research for other data collection methods, a primary benefit of the semi-structured interview is that it permits interviews to be focused while still giving the investigator the autonomy to explore pertinent ideas that may come up in the course of the interview, which can further enhance understanding of the pharmacy service being assessed. The purpose of this narrative review is to summarize methodological considerations and procedures for conducting semi-structured interviews in pharmacy services research. …

An Evaluation Of The Spread And Scale Of Patienttoc™ From Primary Care To Community Pharmacy Practice For The Collection Of Patient-Reported Outcomes: A Study Protocol, Margie Snyder, Betty Chewning, David Kreling, Susan M. Perkins, Lyndee M. Knox, Omolola A. Adeoye-Olatunde, Heather A. Jaynes, Jon C. Schommer, Matthew M. Murawski, Nisaratana Sangasubana, Lisa A. Hillman, Geoffrey M. Curran

Department of Pharmacy Practice Faculty Publications

Background

Medication non-adherence is a problem of critical importance, affecting approximately 50% of all persons taking at least one regularly scheduled prescription medication and costing the United States more than $100 billion annually. Traditional data sources for identifying and resolving medication non-adherence in community pharmacies include prescription fill histories. However, medication possession does not necessarily mean patients are taking their medications as prescribed. Patient-reported outcomes (PROs), measuring adherence challenges pertaining to both remembering and intention to take medication, offer a rich data source for pharmacists and prescribers to use to resolve medication non-adherence. PatientToc™ is a PROs collection software developed …

Adhesive Bonding Of Copper Prepared By Laser-Interference Near The Interference Structuring Limits, H. Liu, J.A. Weibel, P Geoghegan, A.S. Sabu, E.A. Groll

CTRC Research Publications

Adhesive bonding requires adequate surface preparation for ensuring an appropriate joint quality. The interest in adhesive joining has recently expanded to thermal systems having a large number of joints employed for manufacturing and assembly. This study presents surface topology of copper 110 produced by a laser-interference setup that would theoretically yield a periodicity of 1.7 mm, which is near the 1.6-2 mm structuring limit that was estimated based on thermal diffusion length scale for an 8 ns laser pulse. The results show that although the expected periodic interference structuring was not attained, the melt-induced texturing was affected by the laser-interference …

Comparative Analysis Of Battery Electric Vehicle Thermal Management Systems Under Long-Range Drive Cycles, T.J. Shelly, J.A. Weibel, D. Ziviani, E.A. Groll

CTRC Research Publications

Due to increasing regulation on emissions and shifting consumer preferences, the wide adoption of battery electric vehicles (BEV) hinges on research and development of technologies that can extend system range. This can be accomplished either by increasing the battery size or via more efficient operation of the electrical and thermal systems. This study endeavours to accomplish the latter through comparative investigation of BEV integrated thermal management system (ITMS) performance across a range of ambient conditions (-20 °C to 40 °C), cabin setpoints (18 °C to 24 °C), and six different ITMS architectures. A dynamic ITMS modelling framework for a long-range …

Transient Flow Boiling And Maldistribution Characteristics In Heated Parallel Channels Induced By Flow Regime Oscillations, T.A. Kingston, B.D. Olson, J.A. Weibel, S.V. Garimella

CTRC Research Publications

Flow boiling provides an effective means of heat removal but can suffer from thermal and hydrodynamic transients that compromise heat transfer performance and trigger device failure. In this study, the transient flow boiling characteristics in two thermally isolated, hydrodynamically coupled parallel microchannels are investigated experimentally. High-speed flow visualization is synchronized to high-frequency heat flux, wall temperature, pressure drop, and mass flux measurements to provide time-resolved characterization. Two constant and two transient heating conditions are presented. For a constant heat flux of 63 kW/m² into each channel, boiling occurs continuously in both channels and the parallel channel instability is observed …

The Honeycomb Of Engineering, Senay Purzer

School of Engineering Education Open Educational Resources

The Honeycomb of Engineering is a framework that outlines six type of engineering inquiries. The flexible nature of the design process is adapted to guiding different inquiries by highlighting key cells of the honeycomb. With a honeycomb representation, this framework also centers negotiation of risks and benefits at the center of the design process and enables iteration through communication and reflection.

An Energy-Water Corridor Along The Us/Mexico Border: Changing The 'Conversation', Luciano Castillo, William K. George, Jay P. Gore, Ronald Adrian, Humberto Bocanegra Evans, Walter Gutierrez, Carlos Fm Coimbra, Martin Wosnik, David M. Warsinger, Carlos Castillo-Chavez, Leonardo P. Chamorro, Rebecca J. Barthelmie, Sara C. Pryor, John O. Dabiri, Beverly Mckeon, Kenneth T. Christensen, Fazzle Hussain, Harindra J. Fernando, Elaine Oran, James J. Riley, Richard Tapia

School of Mechanical Engineering Working Papers

Over the last decade, migration has become a divisive issue around the world. A large number of countries have erected barriers along their borders to prevent migration, leading to geopolitical tension. Climate change effects will likely exacerbate migration tensions, which will require bold and creative solutions to this difficult social predicament. Here we detail a plan to construct an energy-water corridor along a border that has been the focus of much attention recently: The U.S.-Mexico border. Our proposed solution helps to alleviate some of the negative effects of climate change, while providing energy and economic stimulus to an area that …

Osmocean, Katie Brodersen, Alec Lanter, Maulee Sheth, Nathaniel Kiefer, Emily Bywater, Kumansh Furia, Brittany Cafferty, Hayden Schennum, Yi Xie, Abigail Werner, Deepika Ramchandani, Sandra Cordoba, Akshay Rao, Jun Chen, Abhimanyu Das, David M. Warsinger

School of Mechanical Engineering Working Papers

The objective of this Build & Test was to prove that the Osmocean wave-powered batch reverse osmosis (BRO) system is physically realizable. Through a comprehensive and systematic engineering process, the optimal components for the WEC-side Osmocean coupling were procured, assembled, and tested. The results indicate that a control effort developed for the main loop throttle valve successfully tracks input signals meant to simulate interaction with the BRO system to within 6% error. Future work will include developing a controller for the kidney loop throttle valve to assist in keeping the main loop flow rate constant as well as the direct …

How Engineering Technology Students Perceive Mathematics, Meher R. Taleyarkhan, Anne M. Lucietto, Therese M. Azevedo

School of Engineering Technology Faculty Publications

Engineering Technology (ET) is often combined with that of Engineering. Although Engineering Technology is based on a more hands-on approach and Engineering a theoretical approach, the two majors share a very similar pedagogy in teaching students the same engineering and scientific principles. An observation by an ET professor found that ET students more often than not would eschew the use of mathematical computations and instead provide answers they believe to be correct, without computation or explanation. Leading researchers to delve into possible reasons as to why ET students are reluctant to utilize mathematics. This study utilized in-person interviews with 15 …

In Their Own Words: Forgotten Women Pilots Of Early Aviation, Fred Erisman

Purdue University Press Book Previews

Amelia Earhart’s prominence in American aviation during the 1930s obscures a crucial point: she was but one of a closely knit community of women pilots. Although the women were well known in the profession and widely publicized in the press at the time, they are largely overlooked today. Like Earhart, they wrote extensively about aviation and women’s causes, producing an absorbing record of the life of women fliers during the emergence and peak of the Golden Age of Aviation (1925–1940). Earhart and her contemporaries, however, were only the most recent in a long line of women pilots whose activities reached …

Publisher Evaluation Tool, Nina Collins

Libraries Faculty and Staff Creative Materials

The Publisher Evaluation Tool, or PET Project, is a scored checklist that can help scholars make more informed decisions about whether or not to submit their work to an unknown publisher. The Publisher Evaluation Tool was developed as part of a workshop for graduate students and faculty that explores deceptive journal practices, often called "predatory" practices. It is particularly useful in addressing those journals in the gray area: not quite green light, not quite red light.

Photogrammetry And Texture Baking: Creating Lightweight 3d Objects For Any Vr Headset. In E. Kroski (Ed.) 32 Virtual, Augmented, And Mixed Reality Programs For Libraries, Sarah E. Huber, Andrew Sumner

Libraries Faculty and Staff Scholarship and Research

Patrons will learn how to make 3D objects that are viewable across a range of consumer to high-end VR headsets through the processes of photogrammetry and texture baking. Photogrammetry is an affordable and relatively simple process that recreates objects in 3D with great detail. The process includes taking photos of an object with a Smartphone and then bringing them into open-source software that aligns them into what is called a point cloud. A point cloud is the first processing step in creating a 3D object. Point clouds can be complex and data intensive, so many consumer VR headsets do not …