Assessing the representativeness of wind data for wind turbine site evaluation

Once potential wind turbine sites (either for single installations or clusters) are identified through siting procedures, actual evaluation of the sites must commence. This evaluation is needed to obtain estimates of wind turbine performance and to identify hazards to the machine from the turbulence component of the atmosphere. These estimates allow for more detailed project planning and for preliminary financing arrangements to be secured. The site evaluation process can occur in two stages: (1) utilizing existing nearby data, and (2) establishing and monitoring an onsite measurement program. Since step (2) requires a period of at least 1 yr or more from the time a potential site has been identified, step (1) is often an essential stage in the preliminary evaluation process. Both the methods that have been developed and the unknowns that still exist in assessing the representativeness of available data to a nearby wind turbine site are discussed. How the assessment of the representativeness of available data can be used to develop a more effective onsite meteorological measurement program is also discussed

Dissipative collapse of the adiabatic piston

An adiabatic piston, separating two granular gases prepared in the same macroscopic state, is found to eventually collapse to one of the sides. This new instability is explained by a simple macroscopic theory which is furthermore in qualitative agreement with hard disk molecular dynamics.Comment: 7 pages, 5 figure

Arrow update logic

We present Arrow Update Logic, a theory of epistemic access elimination that can be used to reason about multi-agent belief change. While the belief-changing "arrow updates" of Arrow Update Logic can be transformed into equivalent belief-changing "action models" from the popular Dynamic Epistemic Logic approach, we prove that arrow updates are sometimes exponentially more succinct than action models. Further, since many examples of belief change are naturally thought of from Arrow Update Logic's perspective of eliminating access to epistemic possibilities, Arrow Update Logic is a valuable addition to the repertoire of logics of information change. In addition to proving basic results about Arrow Update Logic, we introduce a new notion of common knowledge that generalizes both ordinary common knowledge and the "relativized" common knowledge familiar from the Dynamic Epistemic Logic literature

The Transformation of Men into Masquerades and Indian Madras into Masquerade Cloth in Buguma, Nigeria

The Kalahari Ijo people of the Niger Delta area of southeastern Nigeria use a group of dark indigo-blue cloths with white patterning to cover the faces of masquerade performers. Subsumed under the name of alubite (masquerade cloth) are at least three distinct types: (1) ukara cloth, an indigo-resist of imported muslin, stitched and dyed by Igbo craftsmen, (2) alubite cloth, a gauze-weave, also an indigo-resist, but of unknown provenance, and (3) pelete bite, an Indian madras from which threads are cut and pulled by Kalahari women to form a new pattern. The first two types of cloth apparently come from non-Kalahari sources. The third, pelete bite, transforms dark blue and white imported madras, using local technology, into a patterned masquerade cloth for which there is a cultural demand. We focus on this transformation, examining particular types of Indian madras considered appropriate for this adaptation and the ways that these cloths are altered (i.e., cut and pulled), their relationship in color and design to ukara and to the other alubite cloths, and the significance of the triangular motif, alu, for depicting water spirits in masquerade performances

The Transformation of Men into Masquerades and Indian Madras into Masquerade Cloth in Buguma, Nigeria

The Kalahari Ijo people of the Niger Delta area of southeastern Nigeria use a group of dark indigo-blue cloths with white patterning to cover the faces of masquerade performers. Subsumed under the name of alubite (masquerade cloth) are at least three distinct types: (1) ukara cloth, an indigo-resist of imported muslin, stitched and dyed by Igbo craftsmen, (2) alubite cloth, a gauze-weave, also an indigo-resist, but of unknown provenance, and (3) pelete bite, an Indian madras from which threads are cut and pulled by Kalahari women to form a new pattern. The first two types of cloth apparently come from non-Kalahari sources. The third, pelete bite, transforms dark blue and white imported madras, using local technology, into a patterned masquerade cloth for which there is a cultural demand. We focus on this transformation, examining particular types of Indian madras considered appropriate for this adaptation and the ways that these cloths are altered (i.e., cut and pulled), their relationship in color and design to ukara and to the other alubite cloths, and the significance of the triangular motif, alu, for depicting water spirits in masquerade performances

The Transformation of Men into Masquerades and Indian Madras into Masquerade Cloth in Buguma, Nigeria

The Kalahari Ijo people of the Niger Delta area of southeastern Nigeria use a group of dark indigo-blue cloths with white patterning to cover the faces of masquerade performers. Subsumed under the name of alubite (masquerade cloth) are at least three distinct types: (1) ukara cloth, an indigo-resist of imported muslin, stitched and dyed by Igbo craftsmen, (2) alubite cloth, a gauze-weave, also an indigo-resist, but of unknown provenance, and (3) pelete bite, an Indian madras from which threads are cut and pulled by Kalahari women to form a new pattern. The first two types of cloth apparently come from non-Kalahari sources. The third, pelete bite, transforms dark blue and white imported madras, using local technology, into a patterned masquerade cloth for which there is a cultural demand. We focus on this transformation, examining particular types of Indian madras considered appropriate for this adaptation and the ways that these cloths are altered (i.e., cut and pulled), their relationship in color and design to ukara and to the other alubite cloths, and the significance of the triangular motif, alu, for depicting water spirits in masquerade performances

A Logic of Blockchain Updates

Blockchains are distributed data structures that are used to achieve consensus in systems for cryptocurrencies (like Bitcoin) or smart contracts (like Ethereum). Although blockchains gained a lot of popularity recently, there is no logic-based model for blockchains available. We introduce BCL, a dynamic logic to reason about blockchain updates, and show that BCL is sound and complete with respect to a simple blockchain model