Application of selection hyper-heuristics to the simultaneous optimisation of turbines and cabling within an offshore windfarm

Global warming has focused attention on how the world produces the energy required to power the planet. It has driven a major need to move away from using fossil fuels for energy production toward cleaner and more sustainable methods of producing renewable energy. The development of offshore windfarms, which harness the power of the wind, is seen as a viable approach to creating renewable energy but they can be difficult to design efficiently. The complexity of their design can benefit significantly from the use of computational optimisation. The windfarm optimisation problem typically consists of two smaller optimisation problems: turbine placement and cable routing, which are generally solved separately. This paper aims to utilise selection hyper-heuristics to optimise both turbine placement and cable routing simultaneously within one optimisation problem. This paper identifies and confirms the feasibility of using selection hyper-heuristics within windfarm optimisation to consider both cabling and turbine positioning within the same single optimisation problem. Key results could not identify a conclusive advantage to combining this into one optimisation problem as opposed to considering both as two sequential optimisation problems.</p

A Geometric Approach Towards Momentum Conservation

In this work, a geometric discretization of the Navier-Stokes equations is sought by treating momentum as a covector-valued volume-form. The novelty of this approach is that we treat conservation of momentum as a tensor equation and describe a higher order approximation to this tensor equation. The resulting scheme satisfies mass and momentum conservation laws exactly, and resembles a staggered-mesh finite-volume method. Numerical test-cases to which the discretization scheme is applied are the Kovasznay flow, and lid-driven cavity flow

Onion storage in sterilized new plastic crates compared to storage in old wooden boxes.

The United States Food and Drug Administration?s (FDA) proposed water rules to implement the Food Safety Modernization Act (FSMA). The FDA has proposed that plastic totes be substituted for wooden bins for the storage on onion bulbs. A preliminary study was conducted to examine the role of wooden storage containers on onion bulb contamination with E. coli. Onions from a furrow-irrigated field using water up to 866 MPN E. coli /100 ml were harvested into 12 old wooden boxes and 12 sterilized new plastic crates. Onions from a drip-irrigated field using water with 0 MPN E. coli /100 ml were harvested into 12 old wooden boxes and 12 sterilized new plastic crates. Onions packed out tended to not have E. coli on the bulb exteriors. The small amount of contamination detected did not appear to be related to the storage containers or irrigation water source

Survival of Escherichia coli on onion during field curing and packout.

The Food and Drug administration has expressed concern that Onions (Allium cepa) irrigated with water contaminated with high rates of Escherichia coli could harbor E. coli on their surface or interior. On the other hand, since onions contain antimicrobial compounds and field conditions may not be conducive to E. coli survival, the E. coli population on the surface of onions might become negligible through the course of field curing. Further, the relationship between the E. coli in the irrigation water to the E. coli on onion bulbs after field curing, harvest, and packout has not been studied. To determine if E. coli should be of concern in onion production, we sought to measure the die-off of E. coli on onions between the last irrigation and harvest and the presence of E. coli on onions after packout. Well water was tested and had no E. coli; ditch water intentionally run across a pasture prior to use had 218 to > 2400 MPN of E. coli/100ml. Onions were sampled from those furrow irrigated (ditch water) and those drip irrigated (well water) starting at lifting 3 September 2013 for four consecutive weeks. At 0 and 28 days after lifting, both interior and exterior of the onions were tested for E. coli. At 7, 14, and 21 days after lifting, only the exterior of the onions was tested. None of the onions contained E. coli internally at 0 or 28 days after lifting. At lifting E. coli was present on the exterior of both the drip and furrow irrigated onions and seemed to be largely unrelated to the irrigation water. The exterior E. coli contamination decreased rapidly after lifting. After harvest and packout on 14 October 2013, no E. coli was detected on the onion bulb exteriors from either irrigation treatment. E. coli introduced into the onion field through furrow irrigation was not present on or in the packed out onion bulbs

GeneHopper: a web-based search engine to link gene-expression platforms through GenBank accession numbers

Global gene-expression analysis is carried out using different technologies that are either array- or sequence-tag-based. To compare experiments that are performed on these different platforms, array probes and sequence tags need to be linked. An additional challenge is cross-referencing between species, to compare human profiles with those obtained in a mouse model, for example. We have developed the web-based search engine GeneHopper to link different expression resources based on UniGene clusters and HomoloGene orthologs databases of the National Center for Biotechnology Information (NCBI)

Movement of Escherichia coli in soil as applied in irrigation water.

The US Food and Drug Administration (FDA) has proposed that If irrigation water exceeds 235 colony-forming units (CFU) of E. coli /100 ml in any one sample or 126 CFU/100 ml in the average of any five consecutive samples, growers would have to cease using that water in any way that directly contacts the surface of fresh produce (FDA 2013). The FDA has proposed that these E. coli levels are an indication of high risk of bacterial contamination of fresh onion (Allium cepa L.) bulbs regardless of the irrigation system. If onion irrigation exceeds 235 CFU, it is not known whether the contaminated water applied by furrow or drip irrigation actually reaches the onion bulb. Soil could filter E. coli and other bacteria before irrigation water reaches onion bulbs. ?Vaquero? onions were grown on Owyhee silt loam. In our preliminary studies reported here, well water free of E. coli was applied to onions through drip irrigation or through furrow irrigation. A second water source was intentionally enriched with E. coli by being run across a pasture and recaptured prior to use. Furrow and drip irrigation were used to apply this water containing 218 to >2400 MPN/100ml for 11+ hours per irrigation. E. coli was monitored in the soil water at the end of irrigation cycles through direct sampling of the soil. Soil water was also sampled using sterile soil solution capsules (SSSC) to sample E. coli in the soil water that moved into place, to differentiate the movement of soil water from the soil water already in place. Soil water measurements were made adjacent to the water source, half way to the bulbs, and immediately adjacent to the onion bulbs. For furrow irrigation with ditch water the E. coli counts in the soil next to the onion bulbs was only 0% and 21% of the counts in the irrigation water following the first and second irrigations, respectively. During subsequent furrow irrigations, the E. coli counts in the soil water next to the onion bulbs exceeded the counts in the irrigation water. For drip irrigation with ditch water, the E. coli counts in the soil solution next to the onion bulbs remained very low. The soil water sampled by the SSSC adjacent to the onion bulbs drip-irrigated with ditch water also had very low E. coli counts