Digital Commons Network^™

Real Work With Real Consequences: Enlisting Community Energy Engineering As An Approach To Envisioning Engineering In Context, Michelle E. Jordan, Steve Zuiker, Wendy Wakefield, Mia Delarosa

Journal of Pre-College Engineering Education Research (J-PEER)

This study describes an illustrative case study from a year-round program that positions middle and high school youth to explore the social value of energy systems in their homes, schools, and neighborhoods. Designed to center existing youth assets, interests and values, Community Energy Engineering (CEE) frames engineering as a tool that students can enlist in order to understand and interrogate their local socio-energy system while also acting to transform it. CEE partners with Title 1 schools in Latino/a neighborhoods in the U.S. southwest. CEE situates youth community-based solar energy innovation projects as consequential, evolving in and with historically contingent engineering …

Vietnamese Americans: History, Education, And Societal Context, Stacy M. Kula, Vinh Q. Tran, Iraise Garcia, Erika Saito, Susan J. Paik

Journal of Southeast Asian American Education and Advancement

While Asian Americans are often depicted as one high-achieving group, there are in fact a wide diversity of Asian American populations that each have their own history and acculturation experiences in the United States. Vietnamese Americans are a particularly unique group; having come with other Southeast Asian refugee groups after the Vietnam War, they are a relatively recent addition to U.S. society with very different circumstances of arrival in comparison with groups from other regions of Asia. This article takes a historical lens to understand the unique factors surrounding Vietnamese American entry to the United States—including policy, societal reception, co-ethnic …

Review Of Chath Piersath's On Earth Beneath Sky, Loom Press, 2020, George Chigas

Journal of Southeast Asian American Education and Advancement

A critical analysis and review of Chath pierSath's 2020 collection of poems and sketches entitled On Earth Beneath Sky published by Loom Press

Hmong American Charter Schools: An Exploratory And Descriptive Study, Pao Lor

Journal of Southeast Asian American Education and Advancement

In this exploratory and descriptive study, I explored, analyzed, and described data provided by existing seven Hmong American charter schools. I aggregated my findings into these categories: communities and history; mission, vision, and/or core/value/future/belief statements; governance structure; curriculum; calendar; student support services; co-curricular activities; student information; staff information; student achievement; parental resources and involvement; communications; budgets/school finance; student enrollment; transportation; and other notable(s). For each category, I summarized the data explored and described, and for most of the categories, I provided supporting details to add depth.

Day 785, Koua Mai Yang

Journal of Southeast Asian American Education and Advancement

Day 785 by Koua Mai Yang

Unifying Aoi Minimization And Remote Estimation — Optimal Sensor/Controller Coordination With Random Two-Way Delay, Cho-Hsin Tsai, Chih-Chun Wang

Department of Electrical and Computer Engineering Technical Reports

The ubiquitous usage of communication networks in modern sensing and control applications has kindled new interests on the timing coordination between sensors and controllers, i.e., how to use the "waiting time'' judicially to improve the system performance. Contrary to the common belief that a zero-wait policy is optimal, Sun et al. showed that a controller can strictly improve the data freshness, the so-called Age-of-Information (AoI), by postponing transmission in order to lengthen the duration of staying in a good state. The optimal waiting policy for the sensor side was later characterized in the context of remote estimation. Instead of focusing …

Fatigue And Its Management In The Aviation Industry, With Special Reference To Pilots, Rajee Olaganathan, Timothy B. Holt, Jackie Luedtke, Brent D. Bowen

Journal of Aviation Technology and Engineering

Abstract Fatigue is a significant contributing factor that reduces human ability and leads to accidents and threatens the safety of aircraft and human lives. Approximately 70% of fatal accidents that occur in commercial aviation operations are due to human factors. More specifically, crew fatigue contributes to nearly 15 to 20% of the accidents (Akerstedt, 2000). These accidents and incidents are associated with pilot fatigue because of the long duty periods, disruption of circadian rhythms, and inadequate sleep that are common among both commercial and military pilots. Though fatigue is seen in all the disciplines associated with the aviation industry, this …

Funds Of Knowledge As Pre-College Experiences That Promote Minoritized Students’ Interest, Self-Efficacy Beliefs, And Choice Of Majoring In Engineering, Dina Verdín, Jessica M. Smith, Juan Lucena

Journal of Pre-College Engineering Education Research (J-PEER)

Pre-college experiences both inside and outside of the classroom inform students’ interest in science, technology, engineering, and mathematics (STEM)-related activities, help them evaluate their knowledge and skills in various tasks, and shape their perceptions of themselves as individuals who can participate in STEM. Yet little empirical research examines the valuable pre-college knowledge, practices, and skills that minoritized students acquire through their home experiences and how they can support students’ transition into an engineering pathway. This study addresses this gap by investigating how students’ funds of knowledge support their interest in engineering, self-efficacy beliefs, and certainty of pursuing an engineering major. …

The Production Of Epistemic Culture And Agency During A First-Grade Engineering Design Unit In An Urban Emergent School, Heidi B. Carlone, Alison K. Mercier, Salem R. Metzger

Journal of Pre-College Engineering Education Research (J-PEER)

Primary school practices are often bound by traditions that perpetuate compliance and skills-based, decontextualized, rote memorization activities. These histories of practice, prevalent in schools serving mostly Black and Brown children, make it inordinately difficult for students to author themselves as knowledge builders (i.e., with epistemic agency), which is a form of injustice. Engineering is a potentially fertile context to support the creation of epistemic culture, whereby young students’ assets are recognized, named, and leveraged as they create and shape the group’s disciplinary knowledge. The authors investigated this potential. The primary research question was: How do first-grade students in an urban …

Equitable Pre-College Engineering Education: Teaching With Racism In Mind, James Holly Jr

Journal of Pre-College Engineering Education Research (J-PEER)

Engineering educators must consider how the cultural backgrounds of students coincide (or diverge) with the epistemological and ontological formation of an engineer. Hence, this work is presented as an exhortation to engineering educators, particularly in a pre-college context, to critically evaluate how race-conscious pedagogies can be exerted in this field. In this autoethnographic study, I convey my attempt to teach engineering with explicit consideration of the sociopolitical context of the Black male youth I taught. As a Black male, I have an insider perspective into the realities that must be navigated to succeed in a racialized society, where Black males …

Making It Your Own: Developing And Administrating Graduate Writing Retreats, Vicki Kennell, Mitch Hobza

Purdue Writing Lab/Purdue OWL Presentations

This workshop lays out the groundwork for developing graduate writing support in the form of writing retreats or camps. Focused on the administrative aspects, it covers audience, logistics, and assessment. All material derives from the context of Purdue Writing Lab events for dissertation writers.

Insects As A Source Of Phenolic Compounds And Potential Health Benefits, M C. Nino, Lavanya Reddivari, C Osorio, I Kaplan, A M. Liceaga

Department of Food Science Faculty Publications

The use of insects in traditional medicine and unveiling the chemical structure of the bright pigments in butterfly wings led to the discovery of bioactive phenolic compounds in the insect bodies. These metabolites have been found not only due to the insect absorption and metabolisation of the plant-derived phenolic present in their diet, but also from the ability of insects to synthesise phenolic compounds de novo through the sclerotisation process. Plant phenolics are secondary metabolites involved in the protection of tissues against UV radiation, herbivores, and pathogens, as well as pigmentation of fruits and flowers. These bioactive compounds exhibit antioxidant, …

Two Generations Of Impostors: Metacognitive Oscillations Between Confidence And Modesty, Michelle Kim, Lisa K. Son

KAUPA Letters

No abstract provided.

Visitor (Tourist) Harassment Research: Delphi Panels, Shweta Singh, Annmarie Nicely, Liping Cai, Jonathan Day

Visitor Harassment Research Unit Special Papers

The harassment of visitors at destinations is a pressing problem globally. It is also an emerging area of scholastic inquiry. This article explores one research technique that, despite its ability to generate new and innovative solutions to a range of problems, is not currently used in visitor harassment (VH) research: the Delphi Panel Research Method. The authors assert, if applied correctly, the technique could significantly advance knowledge in this research stream. The article also explores the technique’s evolution; the broad thoughts on which the technique is based; when the technique should be used; how the technique should be applied; …

Design And Culture: A Transdisciplinary History, Maurice Barnwell

Purdue University Press Book Previews

Design and Culture: A Transdisciplinary History offers an inclusive overview that crosses disciplinary boundaries and helps define the next phase of global design practice. This book examines the interaction of design with advances in technology, developments in science, and changing cultural attitudes. It looks to the past to prepare for the future and is the first book to offer an innovative transdisciplinary design history that integrates multidisciplinary sources of knowledge into a mindful whole. It shows design as a process that expresses goals through values and beliefs, functioning as a major factor in contemporary cultural life.

Starting with the development …

Measurements Of Evaporation And Condensation Mass Transfer Resistances For Surfaces In Residential Dishwashers, Navin Kumar, Joseph Rendall, Kyle Gluesenkamp, Viral Patel, Ahmad Abuheiba, Tugba Turnaoglu

International Refrigeration and Air Conditioning Conference

During the drying phase of a dishwasher, water evaporation and condensation phenomena take place. Some wet surfaces inside the dishwasher are above the local air dewpoint and will experience evaporation, while other surfaces are below the local air dewpoint and will experience condensation. In this study, the evaporation mass transfer resistance of a standard load used in a household dishwasher was experimentally measured. The standardized load measurements were taken in situ during a regular drying phase after the ordinary washing was complete. To determine the mass transfer resistance of condensation, a tub wall sample was cut from the interior of …

Numerical And Experimental Steady-State Investigation Of Supercritical Co2 Gas Cooler Plate Heat Exchanger, Saad Jalil, Ahmed Okasha, James Gebbie, Norbert Müller

International Refrigeration and Air Conditioning Conference

Natural environmentally friendly refrigerants have been considered as alternatives to HFC refrigerants with high Global Warming Potential. In transcritical R744 vapor compression cycles, the heat rejection process occurs above the critical point where the temperature and the pressure are independent of each other. In this work, the gas cooling in a commercial 20 plate heat exchanger (PHE) used as gas cooler is modeled numerically and compared to experimental results. The numerical model is a simplified 2D model, i.e. corrugated plates with zero chevron angle. Four different real gas models are tested in terms of agreement and convergence, and numerical results …

Numerical Study And Validation Of Melting And Solidification In Pcm Embedded Heat Exchangers With Straight Tube, Tanjebul Alam, Daniel Bacellar, Jiazhen Ling, Vikrant Aute

International Refrigeration and Air Conditioning Conference

Latent heat thermal energy storage (LHTES) systems have shown great potential to enable reliable use of renewable energy and load shifting. LHTES offer high storage density and release energy at near constant temperature because of its use of phase change materials (PCMs). The cylindrical PCM heat exchangers (PCMHX) are one of the most used technologies due to their simplicity. Numerical models for such PCMHX enable engineers to estimate their performance for different design parameters and operating conditions without having to test them all. However, modeling the phase change phenomena can be challenging. To better understand the difficulties involving accurate modeling …

An Inverse Method To Estimate Bulk Density And Specific Heat Of Cereal Grains During Heat Pump Drying, Amir Ebrahimifakhar, David Yuill

International Refrigeration and Air Conditioning Conference

Cereal grains are one of the most important sources of nutrients in both developed and developing countries. Quality preservation of cereal grains is a major issue between harvest and utilization. Heat pump grain dryers can be used to preserve grain quality during storage, since grain spoilage can be averted by drying or chilling the grain. In this paper, the use of inverse methods to estimate grain properties during heat pump drying is investigated. An inverse method was developed to estimate the bulk density and specific heat of cereal grains during heat pump drying during the heat and mass transfer processes …

Cfd-Based Analysis & Correlation Development For A Novel Multi-Furcating Heat Exchanger For High Temperature, High Pressure Applications, James Tancabel, William Gerstler, Daniel Erno, Jiazhen Ling, Vikrant Aute, H Peter J. De Bock, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

The thermal efficiency of indirectly heated power cycles such as supercritical carbon dioxide (sCO2) closed Brayton cycles are typically limited by their heat exchangers (HXs), which require high heat transfer effectiveness while operating for tens of thousands of hours under high temperature (>800°C) and pressure (>80 bar) conditions. Previous literature has shown that the use of nature-inspired furcating flow channels represents an exciting opportunity to improve HX thermal-hydraulic performance. In this paper, we analyze the novel multi-furcating HX manifold concept, that was previously shown experimentally to reduce HX volume and mass compared to a baseline oil cooler by …

A Method Of Mapping Heat Exchanger As Simple Polynomials, Deokgeun Park, Fangzhou Guo, Bryan P. Rasmussen

International Refrigeration and Air Conditioning Conference

Conducting economic comparison studies of vapor-compression systems early in the product development process allows the designer to balance competing objectives of raw material costs, life-cycle cost, and system performance. However, detailed performance simulation models typically require iterative solutions at both the component and system levels. These nested iterative models make economic comparison studies computationally prohibitive. To address the challenge of nested iterations, non-iterative polynomial representations of components can be implemented. In this paper, a method to represent the heat exchangers’ effectiveness, pressure loss, refrigerant charge, and mass with non-iterative models is presented. A method of mapping the heat exchanger using …

Assessment Of Metal-Hydride Energy Storage Coupled With Heat Pumps And Solar Pv For Residential Cooling And Heating, Patrick Krane, Davide Ziviani, James E. Braun, Neera Jain, Amy Marconnet

International High Performance Buildings Conference

The extension of time-of-use (TOU) rates to residential buildings has incentivized the use of thermal energy storage (TES) to shift heating and cooling loads away from on-peak hours. At the same time, the growing use of solar photovoltaics (PV) for on-site energy generation with variable buy back rates also encourages the use of TES to store energy generated at hours of peak solar radiation. Metal hydrides are reversible chemical compounds that form when certain metals react with hydrogen. Since these reactions depend on both temperature and pressure, metal hydrides can be used for thermochemical energy storage across a range of …

Latent Heat Energy Storage In A Household Refrigerator Powered By Photovoltaic Electricity – Heat Transfer Design And Technical Viability, Carolina Mira-Hernandez, Cesar A. Isaza-Roldan

International Refrigeration and Air Conditioning Conference

In remote rural areas without access to the electrical grid, the use of a stand-alone photovoltaic (PV) installation to drive a domestic refrigerator can be a viable option for adequate food preservation. In this application, energy storage, probably in electric batteries, is required to guarantee refrigeration conditions during periods without solar energy availability. However, electric batteries are still costly, have limited lifespan and use materials with restricted availability. Latent heat thermal energy storage (LHTES) can be an alternative to electric batteries with reduced cost and lower environmental impact. The current study presents general design guidelines for a system with a …

R1234ze(E) As Drop-In Replacement For R134a In A Micro-Fin Shell-And-Tube Evaporator: Experimental Tests And Calculation Model, Giuseppe Censi, Andrea Padovan

International Refrigeration and Air Conditioning Conference

For the planned phase-down of the hydrofluorocarbon (HFC) R134a in vapor compression cycles, a reasonable and accepted long-term substitute is the hydrofluoro-olefin (HFO) R1234ze(E): due to similar operating pressures of the two fluids, an existing plant can be easily adapted to work with R1234ze(E) as a drop-in replacement for R134a. This works presents a direct comparison of the experimental and calculated performances obtained by using R134a and R1234ze(E) in the same water-cooled chiller at the same operating conditions, focusing on the evaporator, a direct expansion shell-and-tube heat exchanger with micro-fin copper tubes. The working conditions are set to typical air …

Experimental Drying Characteristics Of Fabrics Under Vacuum, William E. Asher, Kashif Nawaz, Cheng-Min Yang, Brian Fricke, Olexiy Buyadgie

International Refrigeration and Air Conditioning Conference

A significant amount of the energy consumed in both residential and commercial sectors is used for clothes drying. In conventional convective clothes drying, hot dry air at atmospheric pressure is passed over and through the clothes in order to remove moisture. Both the heat and water carried out are wasted to ambient resulting in an inefficient process. Additionally, the elevated drying temperatures can damage the fibers of the clothes, reducing their useful lifespan. By drying clothes at pressures below atmospheric, the temperature required to drive out moisture can be reduced. The objective of this study is to investigate the drying …

Design Optimization Of A-Type Heat Exchangers Based On High Performance, Non-Round Tubes, James Tancabel, Vikrant Aute, Jiazhen Ling, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Air-to-refrigerant heat exchangers (HXs) have been the topic of considerable research as they are the fundamental heat transfer components of HVAC&R systems. For residential and commercial applications, indoor heat exchangers are often in A-type configurations to reduce air-conditioner system footprint while still delivering the required cooling or heating. Classical HX design practices typically assume a uniform frontal air velocity profile to facilitate the use of conventional tube-fin airside heat transfer and pressure drop correlations for performance prediction. However, it is well-reported throughout the literature that A-type HXs experience significant airflow maldistribution which can severely degrade HX performance. Additionally, recent advancements …

Lubrication Quality Of Compressor Rolling Bearings With Oil-Refrigerant Mixtures, Rudolf Hauleitner, Guillermo E. Morales-Espejel

International Compressor Engineering Conference

Rolling bearings in refrigerant compressors are lubricated with a mixture of oil and refrigerant. This has always represented a challenge for the bearing lubrication quality estimation (e.g.: kappa or lambda parameters). Even if the mixture rate is known, the exact effect on the lubricant film thickness remains doubtful due to the unknown piezoviscosity and compressibility of the refrigerant and their variation with pressure and temperature. In this work, existing mixing laws for viscosity and piezo-viscosity are examined and adapted to better represent existing measurements. The results are compared with published Daniel plots showing reasonable agreement. Once this is done a …

Field Performance Of Domestic Heat Pumps For Heating And Hot Water In Switzerland Part I: Technology, Methods And State Of The Art Of The Field Studies, Ralph R. Kuster, Manuel Prinzing, Berthold Matthias, Mick Eschmann, Stefan S. Bertsch

International Refrigeration and Air Conditioning Conference

carried out by the Heat Pump Test Center (WPZ) in Buchs SG, Switzerland. In the current study, heat pumps for hydronic heating systems in single family houses within Switzerland have been investigated since 2016. So far, over 20 air-source and geothermal heat pumps have been added to this governmental quality assurance program (Swiss Federal authority EnergieSchweiz). For each heat pump system, more than 40 measured variables are recorded at a time interval of 10 s with calibrated sensors with very low measurement uncertainty. The aim of this field study is to record the real heat pump system efficiency in operation …

3d Cfd Simulation Of A New Ventilated Roof, Michele Calati, Luca Doretti, Cristiano Gatto, Simone Mancin

International High Performance Buildings Conference

In the last decades, energy management and saving have become challenging issues. Considering the building sector (residential or industrial), different technologies have been developed in order to realize tangible energy savings, such as: ventilated roof, double facades, glazed surfaces, etc. Nonetheless, it is important for these new technologies to contemporary assure the human thermal comfort. Passive cooling (or heating) technologies are of actual interest. Low or near-zero energy buildings can only be realized as a result of the good design of all their components; specifically, the roofs call for particular attention as they take large parts of a building’s total …

Design And Development Of A Human Building Interaction Laboratory, Sourabh Yadav, Parveen Dhillon, Orkan Kurtulus, Charles Baxter, Davide Ziviani, W Travis Horton, Panagiota Karava, James E. Braun

International High Performance Buildings Conference

A future is envisioned where buildings are assembled on-site from factory manufactured modular elements that integrate the smart technology needed to enable scalable, cost-effective solutions with autonomous, occupant-responsive, healthy, and sustainable features. The use of modular elements would mean that buildings are assembled rather than constructed on-site with better quality control, less material waste, and more predictable schedules. The use of manufactured building elements can enable more cost-effective integration of new sensors, embedded intelligence, networking, adaptive interfaces, renewable energy, energy recovery, comfort delivery, and resiliency technologies, making high-performance buildings more affordable. To explore and evaluate these modular and intelligent comfort …