9,619 research outputs found
Fruits of Gregory Batesonās epistemological crisis: embodied mind-making and interactive experience in research and professional praxis
Background: The espoused rationale for this special issue, situated āat the margins of cybernetics,ā was to revisit and extend the common genealogy of cybernetics and communication studies. Two possible topics garnered our attention: 1) the history of intellectual adventurers whose work has appropriated cybernetic concepts; and 2) the remediation of cybernetic metaphors. Analysis: A heuristic for engaging in ļ¬rst- and second-order R&D praxis, the design of which was informed by co-research with pastoralists (1989ā1993) and the authorsā engagements with the scholarship of Bateson and Maturana, was employed and adapted as a reļ¬exive in-quiry framework.Conclusion and implications: This inquiry challenges the mainstream desire for change and the belief in getting the communication right in order to achieve change. The authors argue this view is based on an epistemological error that continues to produce the very problems it intends to diminish, and thus we live a fundamental error in epistemology, false ontology, and misplaced practice. The authors offer instead conceptual and praxis possibilities for triggering new co-evolutionary trajectories
A new internal combustion engine configuration: opposed pistons with crank offset
[Abstract]: Theoretical and experimental performance results for a new
internal combustion engine configuration are presented in this paper. The engine is a piston ported, spark ignition petrol engine which consists of two opposed pistons in a single cylinder controlled by two synchronously timed crankshafts at opposite ends of the cylinder. It makes use of crank offset to create the required piston motion aimed at engine efficiency improvements through thermodynamic performance gains. In particular, the engine employs full expansion in which the power stroke displaces a larger volume than the compression stroke, thereby allowing the expanding gas to reach near atmospheric pressure before the exhaust port opens. This allows more work to be done
by each thermodynamic cycle. It also features a greater rate of volume change after combustion than a convention 4-stroke engine for the same crank speed. This reduces the time that the temperature difference between the gas and the cylinder is high relative to a conventional engine which in turn, should reduce the heat lost from the combustion products. Thermodynamic and friction modelling of the engine indicated that efficiencies around 38% might be achieved. However, experiments with a prototype engine demonstrated that friction losses in the engine exceeded
that predicted in the original modelling
Smarr Formula and an Extended First Law for Lovelock Gravity
We study properties of static, asymptotically AdS black holes in Lovelock
gravity. Our main result is a Smarr formula that gives the mass in terms of
geometrical quantities together with the parameters of the Lovelock theory. As
in Einstein gravity, the Smarr formula follows from applying the first law to
an infinitesimal change in the overall length scale. However, because the
Lovelock couplings are dimensionful, we must first prove an extension of the
first law that includes their variations. Key ingredients in this construction
are the Killing-Lovelock potentials associated with each of the the higher
curvature Lovelock interactions. Geometric expressions are obtained for the new
thermodynamic potentials conjugate to variation of the Lovelock couplings.Comment: 20 pages; v2 - references added; v3 - includes important corrections
to result
Rotating bio-reactor cell culture apparatus
A bioreactor system is described in which a tubular housing contains an internal circularly disposed set of blade members and a central tubular filter all mounted for rotation about a common horizontal axis and each having independent rotational support and rotational drive mechanisms. The housing, blade members and filter preferably are driven at a constant slow speed for placing a fluid culture medium with discrete microbeads and cell cultures in a discrete spatial suspension in the housing. Replacement fluid medium is symmetrically input and fluid medium is symmetrically output from the housing where the input and the output are part of a loop providing a constant or intermittent flow of fluid medium in a closed loop
Method for culturing mammalian cells in a perfused bioreactor
A bio-reactor system wherein a tubular housing contains an internal circularly disposed set of blade members and a central tubular filter all mounted for rotation about a common horizontal axis and each having independent rotational support and rotational drive mechanisms. The housing, blade members and filter preferably are driven at a constant slow speed for placing a fluid culture medium with discrete microbeads and cell cultures in a discrete spatial suspension in the housing. Replacement fluid medium is symmetrically input and fluid medium is symmetrically output from the housing where the input and the output are part of a loop providing a constant or intermittent flow of fluid medium in a closed loop
Chemical Potential in the First Law for Holographic Entanglement Entropy
Entanglement entropy in conformal field theories is known to satisfy a first
law. For spherical entangling surfaces, this has been shown to follow via the
AdS/CFT correspondence and the holographic prescription for entanglement
entropy from the bulk first law for Killing horizons. The bulk first law can be
extended to include variations in the cosmological constant , which we
established in earlier work. Here we show that this implies an extension of the
boundary first law to include varying the number of degrees of freedom of the
boundary CFT. The thermodynamic potential conjugate to in the bulk is
called the thermodynamic volume and has a simple geometric formula. In the
boundary first law it plays the role of a chemical potential. For the bulk
minimal surface corresponding to a boundary sphere, the thermodynamic
volume is found to be proportional to the area of , in agreement with
the variation of the known result for entanglement entropy of spheres. The
dependence of the CFT chemical potential on the entanglement entropy and number
of degrees of freedom is similar to how the thermodynamic chemical potential of
an ideal gas depends on entropy and particle number.Comment: 18 pages; v2 - reference adde
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