Digital Commons Network^™

Design Of An Area-Scalable Two-Layer Evaporator Wick For High-Heat-Flux Vapor Chambers, S. Sudhakar, J. A. Weibel, S V. Garimella

CTRC Research Publications

A hybrid two-layer evaporator wick is proposed for passive, high-heat-flux dissipation over large areas using a vapor chamber heat spreader. For such applications, the evaporator wick layer must be designed to simultaneously minimize the device temperature rise and minimize the flow resistance to capillary feeding of the wick. This requires a strategy that exploits the benefits of a thin wick for reduced thermal resistance and a thick wick for liquid feeding. In the present design, a thick cap layer of wick material evenly routes liquid to a thin, low-thermal-resistance base layer through an array of vertical liquid-feeding posts. This two-layer …

Evaluation Of Additively Manufactured Microchannel Heat Sinks, I. L. Collins, J. A. Weibel, L. Pan, S V. Garimella

CTRC Research Publications

Microchannel heat sinks allow removal of dense heat loads from high-power electronic devices at modest chip temperature rises. Such heat sinks are produced primarily using conventional subtractive machining techniques or anisotropic chemical etching, which restricts the geometric features that can be produced. Owing to their layer-by-layer and direct-write approaches, additive manufacturing (AM) technologies enable more design-driven construction flexibility and offer improved geometric freedom. Various AM processes and materials are available, but their capability to produce features desirable for microchannel heat sinks has received limited assessment. Following a survey of commercially mature AM techniques, direct metal laser sintering (DMLS) was used …

The Petal Effect Of Parahydrophobic Surfaces Offers Low Receding Contact Angles That Promote Effective Boiling, T. P. Allred, J. A. Weibel, S V. Garimella

CTRC Research Publications

Despite extensive study of boiling processes and their widespread use in industry, critical interactions between the fluid and surface during boiling remain poorly understood. Simplistic, static descriptions of the contact angle are still relied upon to describe the effects of surface wettability on dynamic interfacial processes that govern boiling. This work demonstrates the critical role of the dynamic wettability characteristics of a surface on bubble growth dynamics and boiling performance. In spite of their superior nucleation behavior, hydrophobic surfaces have received little attention for boiling applications due to their typically premature transition from efficient nucleate boiling to inefficient film boiling. …

Ice Formation Modes During Flow Freezing In A Small Cylindrical Channel, A. Jain, A. Miglani, Y Huang, J. A. Weibel, S V. Garimella

CTRC Research Publications

Freezing of water flowing through a small channel can be used as a nonintrusive flow control mechanism for microfluidic devices. However, such ice valves have longer response times compared to conventional microvalves. To control and reduce the response time, it is crucial to understand the factors that affect the flow freezing process inside the channel. This study investigates freezing in pressure-driven water flow through a glass channel of 500 lm inner diameter using measurements of external channel wall temperature and flow rate synchronized with high-speed visualization. The effect of flow rate on the freezing process is investigated in terms of …

The Wetting State Of Water On A Rose Petal, M. Chakraborty, J. A. Weibel, J. A. Schaber, S V. Garimella

CTRC Research Publications

The rose petal features surface structures that offer unique wetting properties. A water droplet placed on a rose petal forms a high contact angle but exhibits significant contact angle hysteresis, such that relatively large droplets remain stuck to the surface when it is tilted. Understanding this distinctive ‘parahydrophobic’ wetting behavior can provide insight into the design of highly nonwetting, yet highly adhesive, synthetic surfaces. Surface features of the rose petal are characterized via focused ion beam scanning electron microscopy, which reveals microscale papillae that are partially covered with nanoscale striae. The wetting state of water on a rose petal is …

Identification Of Nucleate Boiling As The Dominant Heat Transfer Mechanism During Confined Two-Phase Jet Impingement, M. D. Clark, J. A. Weibel, S V. Garimella

CTRC Research Publications

Thermal management of high-power electronics requires cooling strategies capable of dissipating high heat fluxes while maintaining the device at low operating temperatures. Two-phase jet impingement offers a compact cooling technology capable of meeting these requirements at a low pressure drop. Generally, confined impingement geometries are used in electronics cooling applications, where the flow is constrained between the hot surface and orifice plate. Understanding the primary heat transfer mechanisms occurring as boiling takes place on the surface during jet impingement is important, specifically under such confined conditions. In this study, heat transfer from a copper surface is experimentally characterized in both …

Recognizing Engineering Students’ Funds Of Knowledge: Creating And Validating Survey Measures, Dina Verdín, Jessica M. Smith, Juan Lucena

School of Engineering Education Graduate Student Series

This research base paper examines students who are the first in their families to attend college. Our research seeks to understand the role students’ funds of knowledge makes in first-generation college students’ undergraduate experience. Funds of knowledge are the set of formal/informal knowledge and skills that students learn through family, friends, and communities outside of academic institutions. This paper reports funds of knowledge themes relevant to first-generation college students in engineering and the process of gathering validity evidence to support the funds of knowledge themes.

Using ethnographic and interview data, six themes emerged: connecting experiences, community networks, tinkering knowledge, perspective …

Ledinegg Instability-Induced Temperature Excursion Between Thermally Isolated, Heated Parallel Microchannels, T. A. Kingston, J. A. Weibel, S V. Garimella

CTRC Research Publications

Two-phase flow through heated parallel channels is commonly encountered in thermal systems used for power generation, air conditioning, and electronics cooling. Flow boiling is susceptible to instabilities that can lead to maldistribution between the channels and thereby heat transfer performance reductions. In this study, the Ledinegg instability that occurs during flow boiling in two thermally isolated parallel microchannels is studied experimentally. A dielectric liquid (HFE-7100) is delivered to the parallel channels using a constant pressure source. Both channels are uniformly subjected to the same power, which is in increased in steps. Flow visualization is conducted simultaneously with pressure drop, mass …

Supplemental - Three-Dimensional Liquid-Vapor Interface Reconstruction From High-Speed Stereo Images During Pool Boiling, C. Mira-Hernandez, J. A. Weibel, P. P. Vlachos, S. V. Garimella

CTRC Research Publications

Supplemental Material

Colored Sweet Pepper Cultivar Evaluation For High Tunnel Production In West-Central Indiana, 2018, Petrus Langenhoven

Purdue Fruit and Vegetable Research Reports

This is a compilation of 20 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included.

2018 Melon Variety Trial In Southwestern Indiana, Wenjing Guan, Dan Egel, Dennis Nowaskie, Curtis Marchino, Bhimu Patil, Kevin Crosby

Purdue Fruit and Vegetable Research Reports

This is a compilation of 20 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included.

Applying Empathy-Driven Participatory Research Methods To Higher Education New Degree Development, Lisa Bosman, Abrar Hammoud, Sandhya Arumugam

Technology Leadership and Innovation Faculty Publications

Purpose: Innovation and entrepreneurship are economic drivers promoting competition and growth among organizations throughout the world, many of which would not exist without well-established new product development processes coupled with intentional and strategic focus on research and development. New product development processes, such as the lean start-up methodology and design thinking, are well-known and thriving as a result of empirically-grounded research efforts. Unfortunately, educational institutions and educational researchers, alike, are lagging when it comes to new program/degree development processes. Although the quantity of new degree offerings has increased substantially over the past several decades (in particular for multidisciplinary, interdisciplinary, and …

Using Online Discussions To Develop The Entrepreneurial Mindset In Environmental Engineering Undergraduates: A Case Study, Lisa Bosman, Nathalie Duval-Couetil, Brooke Mayer, Patrick Mcnamara

Technology Leadership and Innovation Faculty Publications

Entrepreneurship is an important aspect of the U.S. and global economy. As such, developing an entrepreneurial mindset is crucial for both engineering students and practicing engineers. The purpose of this paper is to investigate the role of online discussions, as a pedagogical approach, in the development of the entrepreneurial mindset. Online discussions prompts were developed using the Kern Engineering Entrepreneurial Network (KEEN) framework as a guide. The KEEN framework proposes an entrepreneurial mindset can be fostered in students by stimulating curiosity, strengthening connections, and creating value. This paper describes the methodology and rationale that served as the foundation for this …

Di-Sense: In Situ Real-Time Permittivity Estimation And Soil Moisture Sensing Using Wireless Underground Communications, Abdul Salam, Mehmet C. Vuran, Suat Irmak

Faculty Publications

Internet of Underground Things (IOUT) communications have the potential for soil properties estimation and soil moisture monitoring. In this paper, a method has been developed for real-time in situ estimation of relative permittivity of soil, and soil moisture, that is determined from the propagation path loss, and velocity of wave propagation of an underground (UG) transmitter and receiver link in wireless underground communications (WUC). The permittivity and soil moisture estimation processes (Di-Sense, where Di- prefix means two) are modeled and validated through an outdoor UG software-defined radio (SDR) testbed, and indoor greenhouse testbed. SDR experiments are conducted …

Internet Of Things In Smart Agriculture: Enabling Technologies, Abdul Salam, Syed Shah

Faculty Publications

In this paper, an IoT technology research and innovation roadmap for the field of precision agriculture (PA) is presented. Many recent practical trends and the challenges have been highlighted. Some important objectives for integrated technology research and education in precision agriculture are described. Effective IoT based communications and sensing approaches to mitigate challenges in the area of precision agriculture are presented.

Introduction To Systematic Review For The Health Sciences, Jason B. Reed, Bethany Mcgowan, Jane Yatcilla

Libraries Faculty and Staff Creative Materials

Final syllabus for ILS 595 Introduction to Systematic Review for the Health Sciences. Offered spring 2019.

2018 Great Lakes Science Boot Camp Schedule And Assessment Survey, Bethany S. Mcgowan

Libraries Faculty and Staff Creative Materials

The 2018 Great Lakes Science Boot Camp for Librarians was hosted at Purdue University from July 24-27, 2018. The Great Lakes Science Boot Camp is an annual, regional professional development opportunity that exposes STEM librarians to trends in scientific research. These files include a copy of the schedule of events for the 2018 GLSBC, as well as a copy of the survey assessment distributed to participants.

Integrating Technical Standards Into Et Curricula To Meet Abet Standards And Industry Needs, Paul B Mcpherson, Margaret Phillips, Kyle Reiter

Libraries Faculty and Staff Scholarship and Research

With technical standards affecting nearly every aspect of our daily lives, from computers to the components and materials used in car engines, it is critical that undergraduate students are educated on the importance of standards and provided with opportunities to locate and apply relevant technical standards to real world situations. In addition, with ABET accreditation requiring students to have a “basic understanding and familiarity with,” and experience “using” codes and standards, faculty need to consider how such material can be naturally integrated into the curriculum.

At Purdue University, education about codes and standards has been integrated into the mechanical engineering …

Standards Collections: Considerations For The Future, Margaret Phillips

Libraries Faculty and Staff Scholarship and Research

Technical standards are a form of gray literature that describe consensus for a wide variety of applications. They promote safety, quality, and interchangeability of parts. In academic libraries, standards have largely been associated with engineering collections, despite having connections to many disciplines. Engineering and technology accreditation bodies and employers continue to expect graduates to have knowledge and experience with standards upon graduation. This article provides a brief history of standards collection development in academic libraries, discusses the challenges of standards collections, shares a case study of standards information literacy curricula integration, and offers considerations for the future of standards collections.

Unsubstantiated Conclusions: A Scoping Review On Generational Differences Of Leadership In Academic Libraries, Erin R. B. Eldermire, Erla P. Heyns, Heather A. Howard

Libraries Faculty and Staff Scholarship and Research

The academic library profession is experiencing a large turnover in leadership. To date, information on differences in the generational expectations about how to lead is scarce and the research is contradictory. This article presents a scoping review of the literature on generational expectations of academic library leaders. Based on predefined eligibility criteria, the authors searched twelve bibliographic databases and performed a broad web search. 5,435 articles were located and considered for inclusion, however, only four eligible articles were identified and included for analysis. There is little empirical evidence that generational differences are evident in the academic library setting or in …

The Value Of Standards For Teaching, Research, And Facilities Use At Princeton And Purdue, Anya C. Bartelmann, Margaret Phillips

Libraries Faculty and Staff Scholarship and Research

This PowerPoint presentation was delivered as part of the 2019 ASME Library Advisory Board Annual Meeting.

Humanities And Social Sciences Dissertation Bibliographies And Collections: The View From A Stem University, Trevor Burrows, Robert S. Freeman, Erla Heyns, Jean-Pierre V. M. Herubel

Libraries Faculty and Staff Scholarship and Research

This study utilized dissertation bibliographies produced at Purdue University in West Lafayette, Indiana, a STEM-oriented university, to ascertain how well Purdue’s Humanities, Social Science, and Education (HSSE) Library supports doctoral research. To examine a critical mass of data, the authors gathered all the bibliographies of dissertations written in 11 disciplines within the College of Liberal Arts in 2011 and 2015. Data for each citation included year of publication, language, format type, and local availability in print or digitally. Revealing disciplinary trends in using sources, this study provided critical information for reconceptualizing the HSSE Library’s orientation to learning and research and …

Integrating Foundational Data Management Course Into Stem, Wei Zakharov, Sarah Huber, Michael Fosmire

Libraries Faculty and Staff Presentations

This presentation was delivered at the IOLUG conference-Tackling Data in Libraries: Opportunities and Challenges in Serving User Communities in Indianapolis, IN in May 2019. Data literacy is critical for today’s college graduates. Data science education is fundamentally an interdisciplinary endeavor. Since summer 2018, the presenters, information professionals from the libraries, have been working with instructors from Philosophy and Computer and Electrical Engineering to develop three interlocking one-credit courses at the Midwest, public research university, Purdue University. Spring 2019, the courses are offered to engineering sophomore and junior students to explore three key areas of data literacy: management; ethics; and analysis. …

Bibliometrics For Collection Development? A Study Of The Publishing Habits Of Math Faculty At Three Research Institutions, Nastasha E. Johnson

Libraries Faculty and Staff Presentations

No abstract provided.

Potential Reductions In Greenhouse Gas And Fine Particulate Matter Emissions Using Corn Stover For Ethanol Production In China, Yang Yang, Ji-Qin Ni, Weiqing Bao, Lei Zhao, Guang Hui Xie

School of Agricultural & Biological Engineering Faculty Publications

Corn stover is an abundant raw material that can be used to produce ethanol and reduce air pollution. This paper studied the potential reductions in greenhouse gas (GHG) and fine particulate matter (PM_2.5) emissions across China if corn stover was used for ethanol production. Field surveys in nine provincial regions were conducted. Life-cycle assessment (LCA) was used to assess the GHG and PM_2.5 emissions from a corn stover based ethanol system. The LCA system boundaries included several process stages from corn planting to ethanol fuel used in vehicles. Corn stover geographical distributions and emission reduction factors were …

Improved Batch Reverse Osmosis Configuration For Better Energy Effiency, Sandra P. Cordoba, Abhimanyu Das, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Recent progress in batch and semi-batch reverse osmosis processes such as CCRO have shown the promise to be the most efficient desalination systems. Despite their progress, it is critical to further increase their efficiencies, and reduce the downtime between cycles that worsens their cost performance. In this study, we model in new detail a further improved batch desalination system that uses a high pressure feed tank with a reciprocating piston. A high-pressure pump fills the inactive side with the following cycle’s feedwater, providing two main benefits. First, no tank emptying step is needed because feed is already present, thus reducing …

Nanoengineered Condenser Surfaces For Enhancing Transport In Thermal Desalination By Air Gap Membrane Distillation, Yashwant S. Yogi, Sina Nejati, Akshay K. Rao, Rishav Roy, Longnan Li, Soumyadip Sett, Abhimanyu Das, Nenad Miljkovic, Justin A. Weibel, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Thermal desalination is a technique that uses heat or thermal energy to desalinate water, unlike reverse osmosis. Membrane distillation (MD) is a type of thermal desalination technology having various configurations. Air gap membrane distillation (AGMD) is one of the more energy efficient MD configurations, being especially advantageous over other configurations at high salinity. However, the large mass transfer resistance of the air gap dramatically reduces the permeate flux, impairing performance. Higher condensation performance can be achieved by using a smaller air gap size, but typical film-wise condensation flow patterns flood the air gap at the optimal gap size (<1 mm). Experiments show that dropwise and jumping-droplet condensation regimes, achieved using hydrophobic and superhydrophobic condensing surfaces respectively, can improve droplet shedding, allowing for thinner gap sizes. A systemlevel numerical model is used to demonstrate that these surfaces could thereby enable improved energy efficiency (2.1× increase of gained output ratio) while avoiding flooding at gap sizes as small as 0.2 mm. Superhydrophobic surfaces with directional jumping of droplets, specifically in the direction of gravity, are also tested and compared to droplets that jump normal to the condensing surface. Novel condensing surfaces that include a combination of the superhydrophobic and superhydrophilic patterns create flow regimes having pathways for faster permeate removal. Other condensing surfaces, including SLIPS (slippery liquidinfused porous surfaces) and laser-ablated superhydrophobic patterned surfaces are tested to the check the extent to which they improve the permeate removal rate while exhibiting different condensation regimes that merit further exploration.

Evaluation Of 18 Bell Pepper Cultivars In Southwest Michigan, Ron G. Goldy, Kyle Ferrantella

Midwest Vegetable Trial Reports

No abstract provided.

High Tunnel Summer Squash And Zucchini Cultivar Trial, 2018, Rachel Rudolph, John Walsh

Midwest Vegetable Trial Reports

No abstract provided.

Life Cycle Assessment Of Large-Scale Compressed Bio-Natural Gas Production In China: A Case Study On Manure Co-Digestion With Corn Stover, Yang Yang, Ji-Qin Ni, Wanbin Zhu, Guanghui Xie

School of Agricultural & Biological Engineering Faculty Publications

Compressed bio-natural gas (CBG) production from large-scale systems has been recognized as promising because of the abundance of manure and crop residue feedstocks and its environmental friendliness. This study is a life cycle assessment using the local database of an operating large-scale CBG system of manure co-digestion with corn stover in China and eBalance software. The results showed that the system’s Primary Energy Input to Output (PEIO) ratio was 20%. Its anaerobic digestion process was the main contributor to energy consumption, accounting for 76%. Among the six environmental impacts investigated in this study, the global warming potential (GWP) was the …