1,427 research outputs found
Airship logistics: The LTA vehicle; a total cargo system
Design considerations for logistics are dealt with as they pertain to the large rigid LTA vehicle as either a commercial or military cargo carrier. Pertinent factors discussed are: (1) the basic mission; (2) types of payload; (3) the payload space in regards to configuration and sizing, its capacity, and its loadability. A logistic capability comparison of selected cargo airships versus jumbo jets is also made
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Socio-technical transitions towards environmental sustainability through green ICT
We adopt the broad conceptualisation of Green Information Communication Technology (ICT) used by the Organisation for Economic Cooperation and Development (OECD), incorporating perspectives on Information Technology (IT) and Information Systems (IS) which has currency with both business practitioners and policy makers. The objective of our research is to develop a theory of the institutional mechanisms that underpin socio-technical transitions to environmental sustainability through the direct, indirect and systematic effects of Green ICT in and across organisational fields. We construct our theory by drawing on published research in several disciplines focusing on the organisational field of the ICT industry. We present a mechanism-based theoretical model that explains how institutional change in organisational fields can evoke appropriate socio-technical transitions and organisational responses to Green ICT. Systems researchers agree that Green ICT can help lower GHG emissions directly, through energy efficiencies and indirectly by enabling environmentally sustainable business processes. If this research is to be of theoretical or practical relevance it must recognize that government organizations and business enterprises may not adopt policies and strategies on Green ICT because it is rational or moral to do so rather, a web of social, and institutional mechanisms interact to produce the outcomes observed in practice
Higher cyclic operads
We introduce a convenient definition for weak cyclic operads, which is based on unrooted trees and Segal conditions. More specifically, we introduce a category of trees, which carries a tight relationship to the Moerdijk-Weiss category of rooted trees . We prove a nerve theorem exhibiting colored cyclic operads as presheaves on which satisfy a Segal condition. Finally, we produce a Quillen model category whose fibrant objects satisfy a weak Segal condition, and we consider these objects as an up-to-homotopy generalization of the concept of cyclic operad
Ultraviolet and X-ray observations of the BL Lac object PKS 05 8-322
Spectrophotometric observations of the BL Lac object PKS 0548-322 were made with ultraviolet and X-ray instruments on the IUE and HEAO-2 satellites. Two observations in each spectral region, one set of which was obtained simultaneously are presented. A power law of energy index approximately 1.0 gives a good description of the data from ultraviolet through X-ray frequencies. This source is reported to be variable on short timescales (Gilmore 1980); the implications of the spectral properties and apparent variability are discussed in light of a relativistic jet model. Findings support the jet picture of BL Lac objects
Airship economics
Projected operating and manufacturing costs of a large airship design which are considered practical with today's technology and environment are discussed. Data and information developed during an 18-month study on the question of feasibility, engineering, economics and production problems related to a large metalclad type airship are considered. An overview of other classic airship designs are provided, and why metalclad was selected as the most prudent and most economic design to be considered in the 1970-80 era is explained. Crew operation, ATC and enroute requirements are covered along with the question of handling, maintenance and application of systems to the large airship
Enrollment in the 2003/2004 MILC Program: Does Timing Matter?
Agricultural and Food Policy, Marketing,
Constructing the cultural repertoire in a natural disaster: The role of social media in the Thailand flood of 2011
In 2011, Thailand witnessed its worst flooding catastrophe in half a century. In this study, we explored social media as a new and promising weapon to address the physical and morale challenges caused by the natural disaster. A case study was conducted in the context of crisis response, whichinvestigated the use of social media to contribute to the collective cultural repertoire during the natural disaster. By investigating two paths toward the cultural repertoire construction considering different social groups, this study also identified the roles of social media as an information market and an information threshold in the crisis response
Dynamic concentration of motors in microtubule arrays
We present experimental and theoretical studies of the dynamics of molecular
motors in microtubule arrays and asters. By solving a convection-diffusion
equation we find that the density profile of motors in a two-dimensional aster
is characterized by continuously varying exponents. Simulations are used to
verify the assumptions of the continuum model. We observe the concentration
profiles of kinesin moving in quasi two-dimensional artificial asters by
fluorescent microscopy and compare with our theoretical results.Comment: 4pages, 4 figures revte
3D sand printing for automotive mass production applications
Additive manufacturing (AM) of metallic products is seen by many to be commercially viable for only small and highly complex components, manufactured with difficult to machine materials using heat sintering process. In the automotive manufacturing sector, metal hard tooling is often required to produce mass produced components, and the tools are typically bespoke, large in size, inflexible and complex. Conventionally these tools have either been machined from solid billets or near-net-shape cast and then machined to achieve final size. Rapid casting technologies (RCT) use AM 3D sand printing process to manufacture sand mould tools used to create the production tooling. Adopters of this technology can achieve an increasingly agile and robust production process, RCT can also rewrite the design hand book for casting design. The research findings demonstrate that RCT can be successfully applied within the automotive industry, achieving considerable cost and time savings whilst improving quality and product flexibility
The homotopy theory of simplicial props
The category of (colored) props is an enhancement of the category of colored
operads, and thus of the category of small categories. In this paper, the
second in a series on "higher props," we show that the category of all small
colored simplicial props admits a cofibrantly generated model category
structure. With this model structure, the forgetful functor from props to
operads is a right Quillen functor.Comment: Final version, to appear in Israel J. Mat
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