2,883 research outputs found
Low leak rate poppet-and-seat check valve
Valve leakage due to contaminant entrapment and chattering is effectively minimized by a metallic poppet-and-seat check valve designed for use in extreme environmental and fluid temperature conditions
Managing Saline Groundwater Impacts from Irrigation - Designing and Testing Emissions Trading in Coleambally Irrigation Area
Irrigated agriculture often leads to recharge to local and regional groundwater systems greater than what the systems can absorb, resulting in the development of shallow watertables causing salinity and waterlogging. Policy based on emissions trading offers one option for effective management of existing recharge externalities if effective property rights to diffuse emissions can be defined. In this paper we combine the conclusions drawn from biophysical research with economic principles underpinning emissions trading to present such a system. Allocation of net recharge contracts to irrigation farms will internalize the costs associated with saline aquifer impacts. Irrigators may reduce their compliance costs by creating or purchasing credits that reduce recharge through perennial vegetation, engineering solutions or crop rotation options. We discuss the economic impacts of adopting such a policy in the Coleambally Irrigation Area in southwestern New South Wales, Australia. We also demonstrate some of the conclusions drawn from our research using experimental economics.salinity, irrigation, recharge, tradeable emissions, cap and trade, hydrologic-economic modelling, experimental economics
Wind-tunnel investigation of the powered low-speed longitudinal aerodynamics of the Vectored-Engine-Over (VEO) wing fighter configuration
A wind-tunnel investigation incorporating both static and wind-on testing was conducted in the Langley 4- by 7-Meter Tunnel to determine the effects of vectored thrust along with spanwise blowing on the low-speed aerodynamics of an advanced fighter configuration. Data were obtained over a large range of thrust coefficients corresponding to takeoff and landing thrust settings for many nozzle configurations. The complete set of static thrust data and the complete set of longitudinal aerodynamic data obtained in the investigation are presented. These data are intended for reference purposes and, therefore, are presented without analysis or comment. The analysis of the thrust-induced effects found in the investigation are not discussed
Experiments with regulations & markets linking upstream tree plantations with downstream water users
Land-use change in upper catchments impact downstream water flows. As trees use large amounts of water the expansion of upstream plantations can substantially reduce water availability to downstream users. There can also be impacts on downstream salinity due to reduced dilution flows. In some jurisdictions afforestation requires the purchase of water rights from downstream holders, while in others it does not, effectively handing the water rights to the upstream landholders. We consider the economic efficiency and equity (profitability and distributional) consequences of upstream land use change in the presence of a water market under alternate property rights regimes and different salinity scenarios.experimental-economics, tree-plantations, environmental-services, urban, irrigation, stock & domestic, water use, land use,
Infrared spectroscopy of diatomic molecules - a fractional calculus approach
The eigenvalue spectrum of the fractional quantum harmonic oscillator is
calculated numerically solving the fractional Schr\"odinger equation based on
the Riemann and Caputo definition of a fractional derivative. The fractional
approach allows a smooth transition between vibrational and rotational type
spectra, which is shown to be an appropriate tool to analyze IR spectra of
diatomic molecules.Comment: revised + extended version, 9 pages, 6 figure
Knot invariants in lens spaces
In this survey we summarize results regarding the Kauffman bracket, HOMFLYPT,
Kauffman 2-variable and Dubrovnik skein modules, and the Alexander polynomial
of links in lens spaces, which we represent as mixed link diagrams. These
invariants generalize the corresponding knot polynomials in the classical case.
We compare the invariants by means of the ability to distinguish between some
difficult cases of knots with certain symmetries
The case for home based telehealth in pediatric palliative care: a systematic review
Background: Over the last decade technology has rapidly changed the ability to provide home telehealth services. At the same time, pediatric palliative care has developed as a small, but distinct speciality. Understanding the experiences of providing home telehealth services in pediatric palliative care is therefore important
Three particles in an external trap: Nature of the complete J=0 spectrum
Three bosonic, spin-polarized atoms in a spherical oscillator potential
constitutes the simplest nontrivial Bose-Einstein condensate (BEC). The present
paper develops the tools needed to understand the nature of the complete J=0
energy spectrum for this prototype system, assuming a sum of two-body
potentials. The resulting spectrum is calculated as a function of the two-body
scattering length a_sc, which documents the evolution of certain many-body
levels that evolve from BEC-type to molecular-type as the scattering length is
decreased. Implications for the behavior of the condensate excited-state
spectrum and for condensate formation and decay are elucidated. The energy
levels evolve smoothly, even through the regime where the number of two-body
bound states N_b increases by 1, and a_{sc} switches from -infinity to
infinity. We point out the possibility of suppressing three-body recombination
by tuning the two-body scattering length to values that are larger than the
size of the condensate ground state. Comparisons with mean-field treatments are
presented
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