Optimization of Complex Water Supply Network

AbstractThe Millennium drought created critical water shortages throughout Australia and particularly in South East Queensland (SEQ). In response to this the bulk water network was significantly enhanced resulting in large infrastructure augmentations consisting of cross regional pipelines, a desalination plant and a purified recycled water plant. Given that SEQ can transition from drought to flood and vice versa in a short period of time it is a fine balance to operate the new more complicated asset base economically whilst maintaining sufficient supply security. With rising energy prices and the increasing cost of living pressures, there is an immediate need to better understand what optimal grid operation looks like and this is currently being investigated by the Seqwater Decision Support System (DSS).Till now, a network such as the SEQ water grid with its variety of water supply sources of varying reliabilities and complexity of the network has been operated in a relatively manual manner using manual heuristics. Given the number of factors which need to be considered when making decisions about which parts of the network to activate at any one time and the limitations of the human mind to resolve these, means that sub optimal results are frequently generated.The development of a DSS using optimization techniques can help determine the most efficient mode of delivery of water taking into account the operating costs of the various assets within the network, amongst a range of other constraints. This paper goes into detail the application of the optimization technology to the SEQ Water grid

Eliciting conditioned taste aversion in lizards: Live toxic prey are more effective than scent and taste cues alone

© 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd Conditioned taste aversion (CTA) is an adaptive learning mechanism whereby a consumer associates the taste of a certain food with symptoms caused by a toxic substance, and thereafter avoids eating that type of food. Recently, wildlife researchers have employed CTA to discourage native fauna from ingesting toxic cane toads (Rhinella marina), a species that is invading tropical Australia. In this paper, we compare the results of 2 sets of CTA trials on large varanid lizards (“goannas,” Varanus panoptes). One set of trials (described in this paper) exposed recently-captured lizards to sausages made from cane toad flesh, laced with a nausea-inducing chemical (lithium chloride) to reinforce the aversion response. The other trials (in a recently-published paper, reviewed herein) exposed free-ranging lizards to live juvenile cane toads. The effectiveness of the training was judged by how long a lizard survived in the wild before it was killed (fatally poisoned) by a cane toad. Both stimuli elicited rapid aversion to live toads, but the CTA response did not enhance survival rates of the sausage-trained goannas after they were released into the wild. In contrast, the goannas exposed to live juvenile toads exhibited higher long-term survival rates than did untrained conspecifics. Our results suggest that although it is relatively easy to elicit short-term aversion to toad cues in goannas, a biologically realistic stimulus (live toads, encountered by free-ranging predators) is most effective at buffering these reptiles from the impact of invasive toxic prey

The interaction between transpolar arcs and cusp spots

Transpolar arcs and cusp spots are both auroral phenomena which occur when the interplanetary magnetic field is northward. Transpolar arcs are associated with magnetic reconnection in the magnetotail, which closes magnetic flux and results in a "wedge" of closed flux which remains trapped, embedded in the magnetotail lobe. The cusp spot is an indicator of lobe reconnection at the high-latitude magnetopause; in its simplest case, lobe reconnection redistributes open flux without resulting in any net change in the open flux content of the magnetosphere. We present observations of the two phenomena interacting--i.e., a transpolar arc intersecting a cusp spot during part of its lifetime. The significance of this observation is that lobe reconnection can have the effect of opening closed magnetotail flux. We argue that such events should not be rare

First simultaneous measurements of waves generated at the bow shock in the solar wind, the magnetosphere and on the ground

On 5 September 2002 the Geotail satellite observed the cone angle of the Interplanetary Magnetic Field (IMF) change to values below 30° during a 56 min interval between 18:14 and 19:10 UT. This triggered the generation of upstream waves at the bow shock, 13 <I>R<sub>E</sub></I> downstream of the position of Geotail. Upstream generated waves were subsequently observed by Geotail between 18:30 and 18:48 UT, during times the IMF cone angle dropped below values of 10°. At 18:24 UT all four Cluster satellites simultaneously observed a sudden increase in wave power in all three magnetic field components, independent of their position in the dayside magnetosphere. We show that the 10 min delay between the change in IMF direction as observed by Geotail and the increase in wave power observed by Cluster is consistent with the propagation of the IMF change from the Geotail position to the bow shock and the propagation of the generated waves through the bow shock, magnetosheath and magnetosphere towards the position of the Cluster satellites. We go on to show that the wave power recorded by the Cluster satellites in the component containing the poloidal and compressional pulsations was broadband and unstructured; the power in the component containing toroidal oscillations was structured and shows the existence of multi-harmonic Alfvénic continuum waves on field lines. Model predictions of these frequencies fit well with the observations. An increase in wave power associated with the change in IMF direction was also registered by ground based magnetometers which were magnetically conjunct with the Cluster satellites during the event. To the best of our knowledge we present the first simultaneous observations of waves created by backstreaming ions at the bow shock in the solar wind, the dayside magnetosphere and on the ground

Flux ropes in the Hermean magnetotail: Distribution, properties, and formation

An automated method was applied to identify magnetotail flux rope encounters in MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) magnetometer data. The method identified significant deflections of the northâ south component of the magnetic field coincident with enhancements in the total field or dawnâ dusk component. Two hundred fortyâ eight flux ropes are identified that possess wellâ defined minimum variance analysis (MVA) coordinate systems, with clear rotations of the field. Approximately 30% can be well approximated by the cylindrically symmetric, linearly forceâ free model. Flux ropes are most common moving planetward, in the postmidnight sector. Observations are intermittent, with the majority (61%) of plasma sheet passages yielding no flux ropes; however, the peak rate of flux ropes during a reconnection episode is â ¼5 minâ 1. Overall, the peak postmidnight rate is â ¼0.25 minâ 1. Only 25% of flux ropes are observed in isolation. The radius of flux ropes is comparable to the ion inertial length within Mercury’s magnetotail plasma sheet. No clear statistical separation is observed between tailward and planetward moving flux ropes, suggesting the nearâ Mercury neutral line (NMNL) is highly variable. Flux ropes are more likely to be observed if the preceding lobe field is enhanced over background levels. A very weak correlation is observed between the flux rope core field and the preceding lobe field orientation; a stronger relationship is found with the orientation of the field within the plasma sheet. The core field strength measured is â ¼6 times stronger than the local dawnâ dusk plasma sheet magnetic field.Key PointsTwo hundred fortyâ eight flux ropes identified in Mercury’s magnetotail (74 cylindrical and linearly forceâ free)Flux ropes most commonly observed by MESSENGER postmidnight, moving planetwardFlux ropes observed intermittently, but most often when the preceding lobe field is enhancedPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138858/1/jgra53697_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138858/2/jgra53697.pd

Anomalous damping of a low frequency vibrating wire in superfluid He-3-B due to vortex shielding

We have investigated the behaviour of a large vibrating wire resonator in the B-phase of superfluid He-3 at zero pressure and at temperatures below 200 mu K. The vibrating wire has a low resonant frequency of around 60 Hz. At low velocities the motion of the wire is impeded by its intrinsic (vacuum) damping and by the scattering of thermal quasiparticle excitations. At higher velocities we would normally expect the motion to be further damped by the creation of quasiparticles from pair-breaking. However, for a range of temperatures, as we increase the driving force we observe a sudden decrease in the damping of the wire. This results from a reduction in the thermal damping arising from the presence of quantum vortex lines generated by the wire. These vortex lines Andreev-reflect low energy excitations and thus partially shield the wire from incident thermal quasiparticles

Stability of flow and the transition to turbulence around a quartz tuning fork in superfluid He-4 at very low temperatures

We have studied the transition between pure potential flow and turbulent flow around a quartz tuning fork resonator in superfluid He-4 at millikelvin temperatures. Turbulent flow is identified by an additional drag force on the fork prongs due to the creation of quantized vortices. When driven at a constant driving force amplitude, the transition to turbulence causes an abrupt decrease in the velocity amplitude of the prongs. For a range of driving forces, continuous switching is observed between the two flow states. We have made a statistical study of the switching characteristics and of the lifetimes of the unstable states. We find a characteristic velocity nu(star) which separates quasistable turbulent flow at higher velocities and quasistable potential flow at lower velocities. We show that the potential-to-turbulent flow transition is driven by random processes involving remanent vortices pinned to the prongs

New weapons in the toad toolkit: A review of methods to control and mitigate the biodiversity impacts of invasive cane toads (rhinella marina)

© 2017 by The University of Chicago Press. All rights reserved. Our best hope of developing innovative methods to combat invasive species is likely to come from the study of high-profile invaders that have attracted intensive research not only into control, but also basic biology. Here we illustrate that point by reviewing current thinking about novel ways to control one of the world’s most well-studied invasions: that of the cane toad in Australia. Recently developed methods for population suppression include more effective traps based on the toad’s acoustic and pheromonal biology. New tools for containing spread include surveillance technologies (e.g., eDNA sampling and automated call detectors), as well as landscape-level barriers that exploit the toad’s vulnerability to desiccation— a strategy that could be significantly enhanced through the introduction of sedentary, rangecore genotypes ahead of the invasion front. New methods to reduce the ecological impacts of toads include conditioned taste aversion in free-ranging predators, gene banking, and targeted gene flow. Lastly, recent advances in gene editing and gene drive technology hold the promise of modifying toad phenotypes in ways that may facilitate control or buffer impact. Synergies between these approaches hold great promise for novel and more effective means to combat the toad invasion and its consequent impacts on biodiversity

PRILOG PROUČAVANJU SUDSKE PRAKSE O NAKNADI ŠTETE ZBOG OZLJEDE NA RADU (2)

International audienceObservations from the WHISPER (Waves of High frequency and Sounder for Probing of Electron density by Relaxation) instrument on board Cluster, for the interval spanning 2001-2012, are utilized to determine an empirical model describing the total electron density along closed geomagnetic field lines. The model, representing field lines in the region of 4.5≤L -3 above the background power law dependence. The resulting model illustrates some key features of the electron density spatial distribution. The role of the number density distribution, represented by the empirical electron density model, in determining the total plasma mass density is also explored. By combining the empirical electron density model with an empirical average ion mass model, the total plasma mass density distribution is inferred, which includes contributions of both the number density and ion composition of the plasma in the region