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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.

Double-Acting Batch Reverse Osmosis Configuration For Best-In-Class Efficiency And Low Downtime, Sandra Cordoba, Abhimanyu Das, Jorge Leon, Jose M. Garcia, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Energy consumption in reverse osmosis has decreased substantially over the last few decades thanks to the implementation of energy recovery devices, high efficiency pumps, and improved membranes. However, to further increase the adoption of the technology, its energy needs must still be reduced. Batch and semi-batch reverse osmosis configurations have shown potential to be the most energy efficient reverse osmosis variants, but have remaining inefficiencies from brine mixing and high downtime. In this study, we modeled in new detail a further improved double-acting batch reverse osmosis system that uses a high-pressure tank with a reciprocating piston. A high-pressure pump is …

Dosan Ahn Chang-Ho, Young B. Choi

KAUPA Letters

No abstract provided.

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.

The Cobra Effect Of Stimulus Package, Semoon Chang

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 …

Witnesses Of The Gwangju Uprising, Gyonggu Shin

KAUPA Letters

No abstract provided.

One Interpretation Of Buddha’S Teachings, Yeomin Yoon

KAUPA Letters

No abstract provided.

Microelectrodes For Biofilm And Corrosion Research In Drinking Water Distribution Systems, Woo Hyung Lee

KAUPA Letters

Corrosion including biocorrosion is an important, but poorly supported topic in water systems for which there is a definite need for advancements, and microelectrode techniques can offer the potential for advancing the field because they enable focus at the interfaces where reactions are occurring. Further development of this area of research has great merit for sustainable water infrastructure management. The use of microelectrodes has been improved our understanding of disinfectant biofilm penetration and associated biofilm viability and in situ reactivity at metallic pipes, leading to better biofilm control strategy and corrosion control practice for clean and safe drinking water.

Understanding And Improving The 3d Printability Of Metallic Alloys For Laser Powder Bed Fusion Additive Manufacturing, Yongho Sohn

KAUPA Letters

No abstract provided.

Writing Gender In Early Modern Chinese Women's Tanci Fiction, Li Guo

Purdue University Press Book Previews

Women’s tanci, or “plucking rhymes,” are chantefable narratives written by upper-class educated women from seventeenth-century to early twentieth-century China. Writing Gender in Early Modern Chinese Women's Tanci Fiction offers a timely study on early modern Chinese women’s representations of gender, nation, and political activism in their tanci works before and after the Taiping Rebellion (1850 to 1864), as well as their depictions of warfare and social unrest.

Women tanci authors’ redefinition of female exemplarity within the Confucian orthodox discourses of virtue, talent, chastity, and political integrity could be bourgeoning expressions of female exceptionalism and could have foreshadowed protofeminist ideals …

Towards A Techno-Economic Analysis Of Pcm-Integrated Hybrid Hvac Systems, Dre Helmns, David Blum, Armando Casillas, Anand Prakash, Jonathan Woolley, David Vernon, Caton Mande, Michael Woodcox, Spencer Dutton

International High Performance Buildings Conference

Thermal end uses dominate building energy consumption and are a major driver of peak demand. As heating is electrified, peak electrical power required will surge, prompting a need for innovative HVAC system designs and controls. These designs must incorporate novel technologies at the component level and new integration techniques at the system level. One such possibility involves the addition of thermal energy storage (TES) in heating and cooling equipment using a phase change material (PCM) heat exchanger. Here, thermal energy storage via phase change can be used to shift the HVAC system loads to times of lower electricity cost, reduced …

Numerical Investigation Of Carbon Dioxide And Poe Oil Mixture Behavior In An Accumulator In Trans-Critical Heat Pump Mode, Wenying Zhang, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

Carbon dioxide is one of the most promising next-generation refrigerants for air-conditioning applications in electric vehicles because it has the advantages of good heating performance in cold climates and environmental-friendly properties. Nonetheless, there are limited data about reversible CO2 heat pump systems for component-level performance and design. This paper focuses on the impact of different sizes of oil bleed hole on the liquid level and local pressure drop in the accumulator through CFD simulation. Also, we applied the experimental data obtained with a full CO2 HP system for the boundary conditions and the measured properties of liquid POE-CO2 for the …

Prediction Of Lubricant Viscosity From Nonequilibrium Molecular Dynamics Simulation, Lingnan Lin, Mark Kedzeriski

International Refrigeration and Air Conditioning Conference

Nonequilibrium molecular dynamics simulation (NEMD) was used to compute the viscosity of a pure polyol ester, −1 to 1010pentaerythritol tetrahexanoate (PEC6), for a broad range of strain rate (107 s s−1), temperature (258 K to 373 K), and pressure (0.1 MPa to 1 GPa). The Newtonian viscosity was obtained by fitting the viscosities at different strain rates to the Eyring model. The predicted Newtonian viscosities agree well with the experimental data with respect to temperature and pressure. The molecular dynamics simulation is pure prediction because it requires only the chemical structure as the input. Therefore, molecular dynamics can be especially …

Measurement Of Kinematic Viscosity Of Refrigeration Oil And R1234yf Mixture, Shun Morotomi, Keishi Kariya, Akio Miyara

International Refrigeration and Air Conditioning Conference

Refrigerant dissolves in refrigeration oil which is used to lubricate the compressor. Because the viscosity of the oil in which the refrigerant is dissolved is significantly reduced, the rate of the reduction is important information to select a proper oil. However, viscosities have not been sufficiently measured for mixtures of refrigeration oil and new refrigerants which are HFOs and mixtures of HFO and HFC. In order to utilize HFO refrigerants in alternative refrigeration systems, viscosity data of mixtures of refrigeration oil and HFO are essential. In this study, mixture of a refrigeration oil and refrigerant (R410A and R1234yf) viscosity are …

Evaluation Of Contact Resistance And Fin Effectiveness Of Enhanced, Brazed “Dogbone” Fin And Serpentine Tube Heat Exchangers For Air Conditioning And Heat Pump Applications, Daniel Bacellar, Song Li, Cara Martin, Yoram Shabtay, John Black

International Refrigeration and Air Conditioning Conference

The energy consumption due to air conditioning is projected to increase by 1.3 and 4.5 times by 2050 compared to 2010 for members and non-members of the Organization of Economic Coordination and Development (OECD), respectively. Greenhouse Gas (GHG) emissions must be carefully managed to minimize their hazardous contribution to climate change. Air conditioners (AC) and heat pumps (HP) contribute with direct GHG emissions through systemic refrigerant leakage, which consequently degrades the system’s performance and therefore increases its indirect GHG emissions as well. To address this issue, the goals of new systems include minimizing leakage risk, using low global warming potential …

Experimental Confirmation Of Improvement Of Microchannel Condensers By Extraction Circuitry Using R134a, Jun Li, Vladimir Munćan, Dandong Wang, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

This paper experimentally confirmed the benefits of liquid extraction in microchannel condensers. Experiments are conducted on a mobile air conditioning (MAC) system. R134a is used as the working fluid. An extraction tube with valve is added to one condenser so that it can work in two modes: the conventional mode and the extraction mode. Two types of experiments have been conducted: the heat exchanger-level test and the system-level test. In the heat exchanger-level tests, for the same inlet and outlet enthalpy on the refrigerant side, the extraction mode generates more condensate than the conventional mode. The extraction mode also lowers …

Dynamic Modeling Of Packaged Air Conditioner With Micro-Channel Heat Exchanger Condenser, Khaled I. Alghamdi, Christian K. Bach

International Refrigeration and Air Conditioning Conference

Microchannel Heat Exchangers (MCHX) are used in Air Conditioning systems (AC) as an efficient type of Heat Exchangers (HX) because they have compact size, as well as low refrigerant charge. However, using MCHX as condensers can be associated with some problems, including evaporatorcondenser transient charge balance issues. Therefore, this study aims to investigate the impact of using MCHX as a condenser in a packaged air conditioner with a finandtube heat exchanger as an evaporator. The methodology was dynamically modeling the packaged air conditioner in Modelica, considering varying pass configurations of MCHX with several refrigerant charges. The results showed that the …

Water Condensation And Droplet Shedding Behavior On Silica Nanospring Coated Tubes, Joseph Chamberlin, Giancarlo Corti, Andrew Sommers

International Refrigeration and Air Conditioning Conference

In this work, an amorphous silica nanospring (SN) coating is considered as a method to induce hydrophobicity and dropwise condensation on aluminum tubes for both water and methanol. Silica nanosprings offer several advantages over other one-dimensional nanostructures including high surface area (350 m2 g-1), mild growth conditions (350°C, atmospheric pressure), and thermal stability (< 1000°C in air). Special focus in this work will be given to baseline testing and the performance of functionalized SN tubes. Testing to investigate the performance of SN-coated tubes and compare against the performance of uncoated tubing will be conducted in a purpose-built environmental chamber. In order to increase the amount of heat transfer possible within this chamber, 3D-printed fluid-carrying manifolds were designed to significantly increase the amount of available tube surface area. Two different methods of calculating condensation heat transfer coefficients from collected data are compared. Additionally, the existence of an ideal SN coating thickness for maximizing heat transfer and condensation rate is investigated. Future work will focus on using the printed and optimized manifolds to collect data from both a set of uncoated and sets of SN-coated tubes.

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 …

Hydraulic Characterization Of A Adjustable Spiral-Shaped Evaporator, Matthias Feiner, Francisco Javier Fernandez Garcia, Michael Arnemann, Martin Kipfmuller

International Refrigeration and Air Conditioning Conference

To ensure reliability in miniaturized devices or processes with increased heat fluxes, decreasing available cooling surfaces have to be met by novel cooling methods. In order to meet this challenge, a new type of evaporator, the swirl evaporator, was developed. The swirl evaporator is a screw-shaped cylindrical evaporator with an internal diameter between 1 – 3 mm, which is inserted as a blind hole in components with high heat generation. The refrigerant is fed into the blind hole via a capillary, deflected by 180° in the drilling base and flows out of the evaporator again in a helical way (twist …

Analysis Of Electro-Static Assisted Air Dehumidification Processes, Stefano Morcelli, Lorenzo Cremaschi

International Refrigeration and Air Conditioning Conference

The removal of water vapor from the air to reduce relative humidity is a well-known indoor environmental comfort requirement. Common dehumidification approaches require a substantial amount of energy and usually involve the cooling of atmospheric humid air below its dew point or the use of absorbent/adsorbent materials to extract water vapor out of the air. More recently, researchers investigated the effect of electrostatic forces for enhancing water vapor condensation. However, the studies are limited, and there is a lack of correlations that can predict the dehumidification rate. Also, the findings from the literature focused mainly on small flow rates on …

Preliminary Investigations Of A Novel Dual Evaporator Dual Ejector Refrigeration Cycle, Ashwath Bhat, Anandu Surendran, Satyanarayanan Seshadri

International Refrigeration and Air Conditioning Conference

Increasing air conditioning and domestic refrigeration demands pose a massive burden on grid electricity calling for efficient cooling technologies. In this paper, a novel refrigeration architecture -the Dual Evaporator Dual Ejector Cycle (DEDEC) is proposed. The DEDEC utilizes separate high and low-temperature (HT and LT) evaporators and two ejectors, allowing cooling at two different temperatures levels. Compared to the conventional Dual Evaporator Ejector Cycle, the proposed architecture maintains a higher temperature difference between the two evaporators while reducing the throttling losses. This feature finds application for domestic refrigeration where the temperature difference between the fresh food and freezer section is …

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 …

Patch-Based Thermodynamic Property Models For The Subcritical Region, Christopher Laughman, Hongtao Qiao

International Refrigeration and Air Conditioning Conference

Model-based design approaches for vapor-compression cycles depend heavily upon refrigerant property representations that are fast, accurate, and consistent. We describe an approach based upon B-spline interpolants that describes properties such as density, temperature, and specific entropy as the intersection of multiple surfaces, which are referred to as ”patches.” When combined with a transformation of thermodynamic coordinates, this approach can calculate the density over a domain with a maximum absolute percentage error less than ×1P− and a speedup over REFPROP of greater than 100x.

Flow Characteristics In A Microchannel Condensers With Extraction Circuitry, Jun Li, Vladimir Munćan, Dandong Wang, Pega Hrnjak

International Refrigeration and Air Conditioning Conference

The present study reveals the characteristics of refrigerant flow in a microchannel condenser with the extraction circuitry. The extraction circuitry provides a potential to enhance the condenser performance at almost no cost – the condenser geometry is the same except for a few well-sized drainage holes in the header baffle. A microchannel condenser is modified to run in both the extraction mode and the conventional mode. A 1-D finite-volume model is built for the condenser and is validated with R134a experimental data. The capacities agree within ±5 % and the pressure drops agree within ± 25 %. Using this model, …