Local Impact of Humidification on Degradation in Polymer Electrolyte Fuel Cells

Water management represents one of the main challenges in the design and operation of Polymer Electrolyte Fuel Cells (PEFCs). Besides performance, the water level also affects the durability of the cell. Understanding the degradation processes is of vital importance for extending durability of PEFCs by suitable mitigation strategies. In this work, the degradation processes related to operation with fully- and non-humidified gas streams were locally studied. The differences were analyzed using in-situ diagnostic tools, such as segmented cell for local current density measurements, during a 300 h test operating under constant conditions, in combination with local post-test analysis, i.e. SEM/EDX and XPS. The results showed the deep impact of the RH on homogeneity during the degradation process due to the fact that different water distribution influences the chemical environment. Under non-humidified gas streams, the cathode inlet region exhibited increased degradation, whereas with fully humidified gases the bottom of the cell had the higher performance losses. The degradation and the degree of reversibility produced by Pt dissolution, PTFE defluorination, and contaminants such as silicon (Si) and nickel (Ni) were locally evaluate

The Power of the Picturebook: Examining Aesthetics and Critical Literacy for Imagination

This study was to explore the notion of the power of the picturebook. My intent was to read picturebooks aloud with my reading community not for information or to entertain but to connect the picturebook with the experiences of both the reader and the listener and then to come away from the reading someone new. Ten Gifted and Talented, (GT) fifth grade students, five girls and five boys, participated in the study. This group was predominantly white, middle class. After our read aloud session, the reading community then proceeded to examine both the text and the illustrations aesthetically and critically in order to understand the past, question the present, and imagine possibilities of the future. My theoretical framework for the study was based upon the theories of aesthetic experience (Greene, 1995, 2001; Rosenblatt, 1995) and critical literacy (Freire, 2000, 2005). Upon these two theories, I then built the ideas of Picture Theory (Mitchell, 1994, 2005) as it applies to the illustrations in picturebooks, the evolution of the picturebook (Keifer,1995; Lewis, 2001; Nikolajeva & Scott, 2001; Nodelman, 1988; Norton, 1991) and complicated conversation and creative dialogue (Sumara, 1996, 2002; Gallas, 1994, 2003) in order for the reader to use imagination (Greene, 1995, 2001; Sumara, 1996, 2002; Rosenblatt, 1995). This study represented the effort to challenge my reading community to imagine a world of possibility for others and themselves by reading picturebooks through the lenses of aesthetics and critical literacy. It also represented the effort to challenge educators and parents, alike, to consider reading picturebooks aloud, examining both the text and the illustrations, with their students and children. Each new encounter with a picturebook provides the opportunity for children to connect their lived experience with that particular story. Each encounter provides the opportunity to celebrate difference. Each encounter brings about a different way of imagining. This could be imagining what the author wants us to see, feel, or understand, imagining alternate realities other than those we already know, imagining worlds far different from our own, imagining the past in order to understand the present, and imagining the possibilities of the future

Rock, Rhythm, and Rap

This thesis suggests an alternative approach to teaching general music/music appreciation to students in grades 7-12 that incorporates the history of rock and roll and pop music. An approach to teaching rhythm reading skills through rap music is also suggested using Rockin \u27 Rhythm Raps by Cheryl Lavender (1998). Rare is the student that has not been saturated with popular culture during most of his or her lifetime. The case is made that teaching what is relevant to students, namely the history of vernacular music, can contribute significantly to the development of music appreciation. Sixteen lessons are provided. These lessons are designed for a middle or high school general music/music appreciation class that meets two to three times a week for six weeks

#9 - The Comparison of the efficiency of a static PV system vs a solar tracker system

Solar tracking systems can be used to enhance the performance of photovoltaic (PV) systems by following the path of the sun to capture the maximum possible power. The efficiency of a system powered by solar energy may be improved if static PV panels are replaced by a solar tracking system. As the cost of solar systems decreases, the viability of implementing these type of renewable energy systems increases. The purpose of this project was to evaluate the differences in efficiency between a stationary solar panel and a dual axis solar panel that had the capability to track the sun. This project was a part of a larger collaboration through the NSF Research Experience for Teachers program. The multidisciplinary team consisted of two electrical engineering students, five teachers (middle and high school), and an Electrical and Computer Engineering (ECE) college professor that supervised the activities. The system designed consisted of two servo motors which controlled horizontal and vertical movement of the solar panel. A group of four light dependent resistors (LDR) were situated on top of the solar panel with a cross piece separating the LDRs. Both horizontal and vertical motors were programmed to adjust positioning to wherever the light intensity was the greatest according to LDRs. The system also has a temperature and humidity sensor. To enhance the performance of the solar tracker system during cloudy days, an equation that calculates the position of the sun, based on geographical location, date, and time was added to the system. An Arduino microcontroller was used to perform the calculations of the position of the sun during cloudy days, and to read from the sensors, and to send the control signals to the servomotors. The power output of both stationary and solar tracking systems were compared to evaluate which system was most efficient. The paper provides the results of the efficiencies obtained from the solar tracker system and the static PV system

Year of India: Savitri

In this compelling tale of love and devotion, the Hindu heroine, Savitri, challenges both destiny and the god of death himself in her determination to save the life of her husband. This gripping performance is told through the beautiful music of Gustav Holst and the classic South Indian dance form, Bharatanatyam. Presented as part of KSU\u27s Year of India, this special performance features student performers from the KSU School of Music Opera Theater program and Department of Dance. This production is directed by Todd Wedge with choreography by Rifka Mayani and music direction by Judy Cole.https://digitalcommons.kennesaw.edu/musicprograms/1953/thumbnail.jp

Local Impact of Pt Nanodeposits on Ionomer Decomposition in Polymer Electrolyte Membranes

Based on recent theoretical studies, we designed a multistep experimental protocol to understand the impact of environmental conditions around Pt nanodeposits on Membrane chemical degradation. The first experiment probes the local potential at a Pt microelectrode for different rates of permeation of hydrogen and oxygen gases from anode and cathode side. The subsequent degradation experiment utilizes the local conditions taken from the first experiment to analyze local rates of ionomer degradation. The rate of ionomer decomposition is significantly enhanced in the anodic H2-rich membrane region, which can be explained with the markedly increased amount of H2O2 formation at Pt nanodeposits in this region

Enveloping of Catalyst Powder by Ionomer for Dry Spray Coating in Polymer Electrolyte Membrane Fuel Cells

This study presents innovative concepts for improving performance of membrane electrode assemblies (MEAs) prepared by the dry-spraying method introduced by the German Aerospace center (DLR). Dry-spraying is a time and cost effective method that involves solvent-free spraying of catalyst powder on polymer electrolyte membrane. The issue which is resolved in this work is the large ionomer particle size in the conventional method. With mechanical grinding, particle size of the ionomer less than 100 nm were not been achieved. However, here the reactive interface of dry-sprayed MEA is optimized by improving ionic conductivity. Our approach is to modify a carbon support by partially enveloping with Nafion® ionomer followed by incorporating Pt black with it. Additionally, commercial catalyst powder was also modified by two-step preparation process with Nafion® dispersion. In this research, both of these modified powders are sprayed over membrane; hot-pressed; characterized, and have shown improved ionic network and distribution, which corresponds to their higher performances. The improvement in the performance does not correlate with electrode surface area but with the ionomer resistance of the catalytic layer. Therefore, with this study we demonstrate a pathway and methodology to further improve performance by optimizing ionomer structure and networks in the catalytic layer