55,539 research outputs found
Water for Life Strategy in Alberta: Changing Priorities in Canadian Water Policy?
Water resources are being stretched to the limit in Alberta and irrigation activities account for more than 70 percent of consumptive water use in the province. Conflicts among users and potential users may be looming. Pollution of surface water and groundwater and outbreaks of water-borne pathogens have been increasing. Freshwater systems are likely to deteriorate further with impending climate change. Following passage of the Alberta Water Act in 1999 and the Irrigation Districts Act in 2000, which allowed limited transfers of water among water users, the Alberta government issued its Water for Life Strategy in late 2003. The strategy’s principal goals include (1) evaluation of the use of economic instruments to manage water demand by 2007; (2) demonstration of best management practices by 2010; and (3) a 30 percent increase in productivity and efficiency over 2005 levels by 2015. This seems to presage a new era in water management in Alberta, but will the necessary changes in water management be forthcoming? This study examines the need for demand-based management and the constraints that make effective changes in water policy problematic. Evidence from a recent study in the St. Mary’s River Irrigation District highlights problems with water markets.Environmental Economics and Policy,
Multi-limbed locomotion systems for space construction and maintenance
A well developed technology of coordination of multi-limbed locomotory systems is now available. Results from a NASA sponsored study of several years ago are presented. This was a simulation study of a three-limbed locomotion/manipulation system. Each limb had six degrees of freedom and could be used either as a locomotory grasping hand-holds, or as a manipulator. The focus of the study was kinematic coordination algorithms. The presentation will also include very recent results from the Adaptive Suspension Vehicle Project. The Adaptive Suspension Vehicle (ASV) is a legged locomotion system designed for terrestrial use which is capable of operating in completely unstructured terrain in either a teleoperated or operator-on-board mode. Future development may include autonomous operation. The ASV features a very advanced coordination and control system which could readily be adapted to operation in space. An inertial package with a vertical gyro, and rate gyros and accelerometers on three orthogonal axes provides body position information at high bandwidth. This is compared to the operator's commands, injected via a joystick to provide a commanded force system on the vehicle's body. This system is, in turn, decomposed by a coordination algorithm into force commands to those legs which are in contact with the ground
Silicon oxynitride based photonics
Silicon oxynitride is a very attractive material for integrated optics. Besides possessing excellent optical properties it can be deposited with refractive indices varying over a wide range by tuning the material composition. In this contribution we will summarize the key properties of this material class and discuss several application examples. Preliminary results on novel processes, which will lead to largely reduced hydrogen incorporation and enable reflow of SiON material, are being presented
Kerman-Klein-Donau-Frauendorf model for odd-odd nuclei: formal theory
The Kerman-Klein-Donau-Frauendorf (KKDF) model is a linearized version of the
Kerman-Klein (equations of motion) formulation of the nuclear many-body
problem. In practice, it is a generalization of the standard core-particle
coupling model that, like the latter, provides a description of the
spectroscopy of odd nuclei in terms of the properties of neighboring even
nuclei and of single-particle properties, that are the input parameters of the
model. A divers sample of recent applications attest to the usefulness of the
model. In this paper, we first present a concise general review of the
fundamental equations and properties of the KKDF model. We then derive a
corresponding formalism for odd-odd nuclei that relates their properties to
those of four neighboring even nuclei, all of which enter if one is to include
both multipole and pairing forces. We treat these equations in two ways. In the
first we make essential use of the solutions of the neighboring odd nucleus
problem, as obtained by the KKDF method. In the second, we relate the
properties of the odd-odd nuclei directly to those of the even nuclei. For both
choices, we derive equations of motion, normalization conditions, and an
expression for transition amplitudes. We also solve the problem of choosing the
subspace of physical solutions that arises in an equations of motion approach
that includes pairing interactions.Comment: 27 pages, Late
A study of starting time in great hard X-ray flares
An analysis of the starting time in ten great hard X-ray bursts observed with the X-Ray Burst Spectrometer (HXRBS) is presented. It is shown that the impulsive phase of nine of them is composed of a preflash phase, during which the burst is observed up to an energy limit ranging from some tens of keV to 200 keV, followed ten to some tens of seconds afterwards by a flash phase, where the count rate rises simultaneously in all detector channels. For two events strong gamma-ray line emission is observed and is shown to start close to the onset of the flash phase
Mott g-Ratios in Rbx(NH3)1-x and Oxidation state of Rubidium Compounds from XAS
The x-ray absorption spectra (XAS) of Rb metal, Rh,( JH,J, ,, 2H-NbSe2Rb111x and RbBr near the Rb K-edge have been used to ascertain that the oxidation state V of rubidium dissolved in ammonia and intt:rcalated in the layer compound is in the range 0 \u3c V \u3c I. Theobservededge shifts with temperature for semimctals are explainedin terms of the population of band states, and the ratio of the density states near the mobility edge over that calculated for a free electron model, i.e. the Mott ratio g, is ascertained using a semiempirical relation developed for the x-ray absorbance from Is levels to empty states ncar the mobility edge
Foundations of self-consistent particle-rotor models and of self-consistent cranking models
The Kerman-Klein formulation of the equations of motion for a nuclear shell
model and its associated variational principle are reviewed briefly. It is then
applied to the derivation of the self-consistent particle-rotor model and of
the self-consistent cranking model, for both axially symmetric and triaxial
nuclei. Two derivations of the particle-rotor model are given. One of these is
of a form that lends itself to an expansion of the result in powers of the
ratio of single-particle angular momentum to collective angular momentum, that
is essentual to reach the cranking limit. The derivation also requires a
distinct, angular-momentum violating, step. The structure of the result implies
the possibility of tilted-axis cranking for the axial case and full
three-dimensional cranking for the triaxial one. The final equations remain
number conserving. In an appendix, the Kerman-Klein method is developed in more
detail, and the outlines of several algorithms for obtaining solutions of the
associated non-linear formalism are suggested.Comment: 29 page
Alberta's Water for Life Strategy: Some early indications of its acceptance by the irrigation industry in Southern Alberta
Water is essential for sustainable agricultural development - for irrigation of crops, livestock watering, processing, and sustaining farm families. Agriculture uses 71 percent of all water diverted for consumptive use in Canada (Environment Canada, 2004), and is by far the greatest water consumer in Canada. In the absence of a Canadian national water strategy, Alberta has developed a long-term water management plan called the Water for Life Strategy. Its successful implementation will depend largely on the participation of irrigators. This study explores the reaction of irrigators to one of the strategy's main goals - a 30 percent increase in water use efficiency and productivity by 2015 over 2005 levels. The study reveals that irrigators vary significantly in their views as to the extent to which this goal can be reached, and the means by which it should be achieved within agriculture. Further, these responses reflect differences among irrigation districts relating to the extent of water stress, on-farm irrigation water efficiency and natural factors that limit crop diversity in some areas. Ultimately the government may have to revise its 30 percent target and tailor the strategy to irrigation districts as opposed to a broad-based approach.Resource /Energy Economics and Policy,
- …