title: The natural frequency estimation for a system composed of a beam and a spring-mass system

authors: Sun, Xutao

abstract: This study presents an approximate method for determining the natural frequency of a system composed of a beam and a two-degree-of-freedom spring-mass system. The expression for estimating the natural frequency is derived following the standard procedures of the forced vibration analysis of a beam. The results obtained using the current method are in good agreement with those obtained through the dynamic stiffness method, especially when the spring stiffness is large. The innovativeness of the current method is that it reveals the relevance between the natural frequency of the system, the natural frequency of the beam, and the mode shape data at the positions where the spring-mass system is attached to the beam. The method is potentially useful in the dynamic wheel-track interaction analysis because the train wheel is normally simplified as a spring-mass system with high spring stiffness. It may also be applied to natural frequency-based damage detection where an auxiliary spring-mass system is used. When the spring-mass system roves on the beam, the curve of natural frequency versus spring-mass system location would be relevant to the mode shape square which is sensitive to local damage.

text: The natural frequency estimation for a system composed of a beam and a spring-mass system This study presents an approximate method for determining the natural frequency of a system composed of a beam and a two-degree-of-freedom spring-mass system. The expression for estimating the natural frequency is derived following the standard procedures of the forced vibration analysis of a beam. The results obtained using the current method are in good agreement with those obtained through the dynamic stiffness method, especially when the spring stiffness is large. The innovativeness of the current method is that it reveals the relevance between the natural frequency of the system, the natural frequency of the beam, and the mode shape data at the positions where the spring-mass system is attached to the beam. The method is potentially useful in the dynamic wheel-track interaction analysis because the train wheel is normally simplified as a spring-mass system with high spring stiffness. It may also be applied to natural frequency-based damage detection where an auxiliary spring-mass system is used. When the spring-mass system roves on the beam, the curve of natural frequency versus spring-mass system location would be relevant to the mode shape square which is sensitive to local damage.

year: 2023

title: An examination of the effect of messages on cooperation under double-blind and single-blind payoff procedures

authors: Deck, Cary

subjects: Anonymity

abstract: Previous research has suggested that communication and especially promises increase cooperation in laboratory experiments. This has been taken as evidence for internal motivations such as guilt aversion or preference for promise keeping. The goal of this paper was to examine messages under a double-blind payoff procedure to test the alternative explanation that promise keeping is due to external influence and reputational concerns. Employing a 2×2 design, we find no evidence that communication increases the overall level of cooperation in our experiments with double-blind payoff procedures. However, we also find no evidence that communication impacts cooperation in our experiments with single-blind payoff procedures. Further, the payoff procedure does not appear to impact aggregate cooperation.

text: An examination of the effect of messages on cooperation under double-blind and single-blind payoff procedures Previous research has suggested that communication and especially promises increase cooperation in laboratory experiments. This has been taken as evidence for internal motivations such as guilt aversion or preference for promise keeping. The goal of this paper was to examine messages under a double-blind payoff procedure to test the alternative explanation that promise keeping is due to external influence and reputational concerns. Employing a 2×2 design, we find no evidence that communication increases the overall level of cooperation in our experiments with double-blind payoff procedures. However, we also find no evidence that communication impacts cooperation in our experiments with single-blind payoff procedures. Further, the payoff procedure does not appear to impact aggregate cooperation.

year: 2013

title: Speaking the unspoken: Racism, sport and Māori

authors: Hippolite, Holly Raima

subjects: New Zealand

abstract: In this paper, we consider the silence that surrounds issues of racism in New Zealand sport. We argue that the intersection of two key ideologies – New Zealand’s purported history of good race relations, and the positive contribution that sport is believed to make to racial equality – contribute to a culture of silence in which it is difficult to talk about, let alone discuss constructively, Māori experiences of racism. Our aim is to put the issue on the agenda through engagement with ten experienced Māori sport participants, coaches and administrators whose experiences demonstrate the existence of, and pain caused by, cultural and institutional racism in New Zealand sport. In this aim, we do not seek to hide behind a veil of neutrality or objectivity. Rather, following a kaupapa Māori research approach, our interest is in bringing to light the voices, frustrations and concerns of Māori sportspeople in order to contribute to a much-needed conversation.

text: Speaking the unspoken: Racism, sport and Māori In this paper, we consider the silence that surrounds issues of racism in New Zealand sport. We argue that the intersection of two key ideologies – New Zealand’s purported history of good race relations, and the positive contribution that sport is believed to make to racial equality – contribute to a culture of silence in which it is difficult to talk about, let alone discuss constructively, Māori experiences of racism. Our aim is to put the issue on the agenda through engagement with ten experienced Māori sport participants, coaches and administrators whose experiences demonstrate the existence of, and pain caused by, cultural and institutional racism in New Zealand sport. In this aim, we do not seek to hide behind a veil of neutrality or objectivity. Rather, following a kaupapa Māori research approach, our interest is in bringing to light the voices, frustrations and concerns of Māori sportspeople in order to contribute to a much-needed conversation.

year: 2010