32,949 research outputs found
Applying and Extending the Sustainable Value Method related to Agriculture â an Overview
Sustainable Value is a method to measure the contribution of an economic entity, such as a farm or the entire agricultural sector, towards the sustainability (sustainable development) of a region, a country or on a global scale. A positive sustainable value is created once resources are used more efficiently than by a benchmark. It shows the excess return that is created or lost by the use of economic, environmental and social resources by an economic entity relative to a benchmark. The purpose of this paper is to give an overview on the characteristics and requirements of the SV and to provide information on (a) possible applications and (b) extensions of the SV method related to the agricultural sector. A particular emphasis is put on the choice of sustainability indicators (resource figures, welfare figure) to be included, the generic steps of SV calculation, the meaning of weighting and aggregation in the SV, the role of the Return-to-Cost Ratio in taking farm size into consideration, and the interpretation and communication of the results of an agriculture-related SV assessment. After sketching out possible extensions and variations of the SV method, the paper closes with a summary of those aspects to keep in mind when applying the SV to agriculture.sustainability contributions, value, measurement, Environmental Economics and Policy,
Star Formation Quenching Timescale of Central Galaxies in a Hierarchical Universe
Central galaxies make up the majority of the galaxy population, including the
majority of the quiescent population at . Thus, the mechanism(s) responsible for quenching
central galaxies plays a crucial role in galaxy evolution as whole. We combine
a high resolution cosmological -body simulation with observed evolutionary
trends of the "star formation main sequence," quiescent fraction, and stellar
mass function at to construct a model that statistically tracks the
star formation histories and quenching of central galaxies. Comparing this
model to the distribution of central galaxy star formation rates in a group
catalog of the SDSS Data Release 7, we constrain the timescales over which
physical processes cease star formation in central galaxies. Over the stellar
mass range to we infer quenching
e-folding times that span to with more massive
central galaxies quenching faster. For , this implies a total migration time of from the star formation main sequence to quiescence. Compared
to satellites, central galaxies take longer to quench
their star formation, suggesting that different mechanisms are responsible for
quenching centrals versus satellites. Finally, the central galaxy quenching
timescale we infer provides key constraints for proposed star formation
quenching mechanisms. Our timescale is generally consistent with gas depletion
timescales predicted by quenching through strangulation. However, the exact
physical mechanism(s) responsible for this still remain unclear.Comment: 16 pages, 11 figure
Squeeze-film dampers for turbomachinery stabilization
A technique for investigating the stability and damping present in centrally preloaded radially symmetric multi-mass flexible rotor bearing systems is presented. In general, one needs to find the eigenvalues of the linearized perturbation equations, though zero frequency stability maps may be found by solving as many simultaneous non-linear equations as there are dampers; and in the case of a single damper, such maps may be found directly, regardless of the number of degrees of freedom. The technique is illustrated for a simple symmetric four degree of freedom flexible rotor with an unpressurized damper. This example shows that whereas zero frequency stability maps are likely to prove to be a simple way to delineate multiple solution possibilities, they do not provide full stability information. Further, particularly for low bearing parameters, the introduction of an unpressurized squeeze film damper may promote instability in an otherwise stable system
Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly progress report no. 11, Mar. 1966
Breadboard model development of integrated static inverte
Thermal boundary resistance at Si/Ge interfaces determined by approach-to-equilibrium molecular dynamics simulations
The thermal boundary resistance of Si/Ge interfaces as been determined using
approach-to-equilibrium molecular dynamics simulations. Assuming a reciprocal
linear dependence of the thermal boundary resistance, a length-independent bulk
thermal boundary resistance could be extracted from the calculation resulting
in a value of 3.76x10 m K/W for a sharp Si/Ge interface and thermal
transport from Si to Ge. Introducing an interface with finite thickness of 0.5
nm consisting of a SiGe alloy, the bulk thermal resistance slightly decreases
compared to the sharp Si/Ge interface. Further growth of the boundary leads to
an increase in the bulk thermal boundary resistance. When the heat flow is
inverted (Ge to Si), the thermal boundary resistance is found to be higher.
From the differences in the thermal boundary resistance for different heat flow
direction, the rectification factor of the Si/Ge has been determined and is
found to significantly decrease when the sharp interface is moderated by
introduction of a SiGe alloy in the boundary layer.Comment: 7 pages, 6 figure
Design, development and delivery of one /1/ breadboard and three /3/ production units of a 75 VA integrated static inverter Monthly report no. 15
Flip-flop arrays, power transistors, epitaxial stress, and other technological developments in integrated static inverter progra
Holderlins Einsamkeit und Dichtertum
Paper by Walther L. Hahn, Associate Professor of German at the University of Orego
Agent-Based Team Aiding in a Time Critical Task
In this paper we evaluate the effectiveness of agent-based aiding in support of a time-critical team-planning task for teams of both humans and heterogeneous software agents. The team task consists of human subjects playing the role of military commanders and cooperatively planning to move their respective units to a common rendezvous point, given time and resource constraints. The objective of the experiment was to compare the effectiveness of agent-based aiding for individual and team tasks as opposed to the baseline condition of manual route planning. There were two experimental conditions: the Aided condition, where a Route Planning Agent (RPA) finds a least cost plan between the start and rendezvous points for a given composition of force units; and the Baseline condition, where the commanders determine initial routes manually, and receive basic feedback about the route. We demonstrate that the Aided condition provides significantly better assistance for individual route planning and team-based re-planning
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