title: Efficiency of cycled batteries analyzed through voltage-current phase differences

authors: Wilson, Marcus T.

abstract: Ageing of rechargeable batteries is routinely characterized in the frequency domain by electrochemical impedance spectroscopy, but the technique requires laboratory measurements to be made on a time scale of days. However, the normal cycling of a battery as it is used in situ provides equivalent information in the time domain, though extracting robust frequency information from a time series is challenging. In this work, we explore, in the time domain, the relationship between instantaneous voltage-current phase difference and cycle efficiency. Moreover, we demonstrate that phase measures can be used to identify battery ageing. We have cycled a 250 mA h Nickel-Cobalt cell several hundred times and used Hilbert Transforms to identify phase difference between voltage and current. This phase difference becomes closer to zero as the battery ages, commensurate with a drop in energy cycle efficiency. In another experiment, we applied a synthetic current profile mimicking behaviour of an electric car cell, to a 3.2 A h LiNiMnCoO2 cell, for 100 days. For this more complicated profile with a wide range of frequency content, we used wavelet analysis to identify changes in phase difference and impedance as the battery aged. For this cell, drop in cycle efficiency was associated with a rise in internal resistance. The results imply that time-series analysis of in situ measurements of voltage and current, when applied with equivalent circuit models and underlying theory, can identify markers of battery ageing.

text: Efficiency of cycled batteries analyzed through voltage-current phase differences Ageing of rechargeable batteries is routinely characterized in the frequency domain by electrochemical impedance spectroscopy, but the technique requires laboratory measurements to be made on a time scale of days. However, the normal cycling of a battery as it is used in situ provides equivalent information in the time domain, though extracting robust frequency information from a time series is challenging. In this work, we explore, in the time domain, the relationship between instantaneous voltage-current phase difference and cycle efficiency. Moreover, we demonstrate that phase measures can be used to identify battery ageing. We have cycled a 250 mA h Nickel-Cobalt cell several hundred times and used Hilbert Transforms to identify phase difference between voltage and current. This phase difference becomes closer to zero as the battery ages, commensurate with a drop in energy cycle efficiency. In another experiment, we applied a synthetic current profile mimicking behaviour of an electric car cell, to a 3.2 A h LiNiMnCoO2 cell, for 100 days. For this more complicated profile with a wide range of frequency content, we used wavelet analysis to identify changes in phase difference and impedance as the battery aged. For this cell, drop in cycle efficiency was associated with a rise in internal resistance. The results imply that time-series analysis of in situ measurements of voltage and current, when applied with equivalent circuit models and underlying theory, can identify markers of battery ageing.

year: 2024-03-07

title: The Social Relations and Interactions of a First Person Shooter (FPS) Gamer

authors: McQuarters, Glen Matthew

subjects: First person shooters

abstract: Video games have been part of society for over 40 years. During this period, a stereotypical image of a person who plays videogames has formed. Influenced by the stereotypical image (young, loner males, pale, socially inept, overweight, and possibly aggressive or violent), psychological research has focused on the possible negative effects of playing first person shooter video games. Contrary to the stereotype, first person shooter video games can be a medium in which social relationships are formed and maintained. This study aims to explored the social relationships and interactions of players of first person shooter video games in all locations of play, and how these relationships and interactions influenced the game experience, and how players managed these relationships and interactions. This research was done using qualitative interviews with 12 current first person shooter gamers. The study found that between non-persistent game worlds, technological advancements, and the potentially persistent social relationships, a large diversity of social relationships and interactions occur in and emerge from first person shooter video games. These social relationships and interactions play a central role in the enjoyment of playing first person shooter video games. The study found the interactions that are possible, happen in many different forms. The relationships found in the study developed from several different settings with playing together and friends’ friend being the most common start of a relationship. As well, the participants’ reported a level structure for the relationships that are part of their first person shooter gaming. The study also describes the interactions of players while gaming as being seen as mostly good, with a few antisocial acts committed. These findings are discussed in comparison with literature from other game genres on the social interactions and relationships of players. The seemingly “unsocial” and virtually violent first person shooter game world has been shown to encompass surprisingly rich and diverse social relationships.

text: The Social Relations and Interactions of a First Person Shooter (FPS) Gamer Video games have been part of society for over 40 years. During this period, a stereotypical image of a person who plays videogames has formed. Influenced by the stereotypical image (young, loner males, pale, socially inept, overweight, and possibly aggressive or violent), psychological research has focused on the possible negative effects of playing first person shooter video games. Contrary to the stereotype, first person shooter video games can be a medium in which social relationships are formed and maintained. This study aims to explored the social relationships and interactions of players of first person shooter video games in all locations of play, and how these relationships and interactions influenced the game experience, and how players managed these relationships and interactions. This research was done using qualitative interviews with 12 current first person shooter gamers. The study found that between non-persistent game worlds, technological advancements, and the potentially persistent social relationships, a large diversity of social relationships and interactions occur in and emerge from first person shooter video games. These social relationships and interactions play a central role in the enjoyment of playing first person shooter video games. The study found the interactions that are possible, happen in many different forms. The relationships found in the study developed from several different settings with playing together and friends’ friend being the most common start of a relationship. As well, the participants’ reported a level structure for the relationships that are part of their first person shooter gaming. The study also describes the interactions of players while gaming as being seen as mostly good, with a few antisocial acts committed. These findings are discussed in comparison with literature from other game genres on the social interactions and relationships of players. The seemingly “unsocial” and virtually violent first person shooter game world has been shown to encompass surprisingly rich and diverse social relationships.

year: 2013

title: Moko – A Research Project

authors: Te Awekotuku, Ngahuia

subjects: Maori

abstract: Moko colours the lives, and the skins, of all the people involved in the making of this book “Mau Moko”, which began as the Marsden project, “Ta Moko – Culture, Body Modification, and the Psychology of Identity”, 2001-2005. We proposed to study the origins, significance, technology and practice of Ta Moko from the pre-contact period to contemporary times, and to explore how this important art form has become a dynamic and positive assertion of being Maori in our changing world.

text: Moko – A Research Project Moko colours the lives, and the skins, of all the people involved in the making of this book “Mau Moko”, which began as the Marsden project, “Ta Moko – Culture, Body Modification, and the Psychology of Identity”, 2001-2005. We proposed to study the origins, significance, technology and practice of Ta Moko from the pre-contact period to contemporary times, and to explore how this important art form has become a dynamic and positive assertion of being Maori in our changing world.

year: 2008