Sliding on carbon nanotube arrays

Adhesion, friction and wear of Single-Walled Nanotube (SWNT) and multi-walled nanotube arrays have been investigated. SWNT arrays exhibit lower adhesion and friction values on account of the lower van der Waals’ forces resulting from lower packing density and higher flexibility. Wear tests show that both arrays do not wear. Tip wear and friction force in the SWNT array are lower due to lower adhesion and higher flexibility of the SWNTs, which lead to less resistance to the motion of the tip.     

What is a chemical property?

Despite the currently perceived urgent need among contemporary philosophers of chemistry for adjudicating between two rival metaphysical conceptual frameworks—is chemistry primarily a science of substances or processes?—this essay argues that neither provides us with what we need in our attempts to explain and comprehend chemical operations and phenomena. First, I show the concept of a chemical property can survive the abandoning of the metaphysical framework of substance. While this abandonment means that we will need to give up essential properties, contingent properties can give us all the stability we need to account for chemical continuity as well as change. I then go on to show that this attention to clusters of contingent properties does not force us into the arms of an alternative process metaphysical framework either. Finally, I sketch a view I call particularism with respect to chemical properties on analogy with moral particularism. I conclude by sketching some of the implications for the field of philosophy of chemistry of my proposal that we abandon our interest in the metaphysical question of what chemistry is primarily about in favor of a broadly scientific particularism with respect to kinds and properties.     

Effect of Landmark Type on Route Memory in Unfamiliar Homogenous Environment

Landmarks are objects that have salience that is either visual, semantic or structural. Recent researches have pointed out observer characteristics that make a landmark salient. These have been termed cognitive salience. This study investigated the effects of two components of cognitive salience, familiarity and degree of recognition, on route memory. The first experiment examined the effect of familiarity of landmark and ease with which it could be recognized (degree of recognition) on remembering a route, while in the second experiment only degree of recognition was varied while holding familiarity constant. Two types of landmarks (text and image) were shown to participants who had to recollect course taken at decision points during wayfinding tasks. Participants were shown navigation videos generated using Squareland Model. The videos had six decision points each having one landmark, and the participants were required to indicate the direction of the turn when the landmarks were shown again. Results showed that pictorial landmarks (high degree of recognition) were better facilitators of route memory than textual landmarks (low degree of recognition). Results also indicated that familiar buildings served as better landmarks than unfamiliar buildings. In the second experiment another level of degree of recognition (medium) was added and compared with high and low levels. Results confirmed the findings of the first experiment with high degree of recognition being the best facilitator followed by medium and low degree of recognition. Our findings lend empirical support to the concept of cognitive salience proposed by Caduff and Timpf (Cogn Process 9:249–267, 2008) and highlight the importance of observer characteristics in determining what constitutes as good landmark.