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Optimisation of the hydrotesting sequence in tank farm construction using an adaptive genetic algorithm with stochastic preferential logic
In the construction of tank farms there is a requirement for the tanks to be hydro-tested in order to verify that they are leak proof as well as proving the lack of differential settlement in the foundations. The tanks will be required to be filled to a predetermined level and then to maintain this loaded state for a certain period of time before being drained. In areas such as the Middle East water for hydro-testing is not freely available as sea water is often not suitable for this purpose, so fresh water needs to be produced or transported to the construction site for this purpose. It is therefore of major benefit to the project to schedule the hydro-testing of the tanks in such a manner as to minimize the utilization of hydro-test water.
This problem is a special case of the Resource Constrained Project Scheduling Problem (RCPSP) and in this research we have modified our previously developed Fitness differential adaptive genetic algorithm [4, 6 & 7] to the solution of this real world problem.
The Algorithm has been ported from the original MATLAB code into Microsoft Project using VBA in order to provide a more user friendly, practical interface
Effects of Mosquito Control Chemicals on Aquatic Fauna
No mosquito abatement districts have ever been organized in Arkansas. Mosquito control efforts have been largely adulticiding operations by either aerial application or ground thermal fogging machines. Practically no chemical applications have been directed at the larval stage in residual water in ditches and depressions from which adult populations arise. Some larviciding with ethyl parathion has been done in ricefields. Although the treatment is very effective in mosquito reduction, voluntary treatment has not been completely successful. Because relatively little insecticide has been used as a larvicide in Arkansas, it was possible to evaluate the effect of recommended larvicides on non-target organisms in the aquatic environment. A developing mosquito control demonstration program in the rice-producing area provided the study site
Craton-scale variations in crustal evolution: new insights from Scottish Highland detrital zircon
Zinc calixarene complexes for the ring opening polymerization of cyclic esters
Reaction of Zn(CâFâ
)â·toluene (two equivalents) with 1,3-dipropoxy-p-tert-butyl-calix[4]arene (LÂčHâ) led to the isolation of the complex [{Zn(CâFâ
)}âLÂč] (1), whilst similar use of Zn(Me)â resulted in the known complex [{Zn(Me)}âLÂč] (2). Treatment of LÂčHâ with in situ prepared Zn{N(SiMeâ)â}â in refluxing toluene led to the isolation of the compound [(Na)ZnN(SiMeâ)âLÂč] (3). The stepwise reaction of LÂčHâ and sodium hydride, followed by ZnClâ and finally NaN(SiMeâ)â yielded the compound [Zn{N(SiMeâ)â}âLÂč] (4). The reaction between three equivalents of Zn(CâFâ
)â·toluene and oxacalix[3]arene (LÂČHâ) at room temperature formed the compound {[Zn(CâFâ
)]âLÂČ} (5); heating of 5 in acetonitrile caused the ring opening of the parent oxacalix[3]arene and rearrangement to afford the complex [(LÂČ)Znâ(CâFâ
)(R)(RH)OH]·5MeCN R = CâFâ
CHâ-(p-á”BuPhenolate-CHâOCHââ)ââp-á”BuPhenolate-CHâOâ»)Âłâ» (6). The molecular structures of the new complexes 1, 3 and 6, together with that of the known complex 2, whose solid state structure has not previously been reported, have been determined. Compounds 1, 3â5 have been screened for the ring opening polymerization (ROP) of Δ-caprolactone (Δ-CL) and rac-lactide. Compounds featuring a ZnâCâFâ
fragment were found to be poor ROP pre-catalysts as they did not react with benzyl alcohol to form an alkoxide. By contrast, compound 4, which contains a zinc silylamide linkage, was the most active of the zinc-based calix[4]arene compounds screened and was capable of ROP at ambient temperature with 65% conversion over 4 h
Antiferromagnetic ordering of energy levels for spin ladder with four-spin cyclic exchange: Generalization of the Lieb-Mattis theorem
The Lieb-Mattis theorem is generalized to an antiferromagnetic spin-ladder
model with four-spin cyclic exchange interaction. We prove that for J>2K, the
antiferromagnetic ordering of energy levels takes place separately in two
sectors, which remain symmetric and antisymmetric under the reflection with
respect to the longitudinal axis of the ladder. We prove also that at the
self-dual point J=2K, the Lieb-Mattis rule holds in the sectors with fixed
number of rung singlets. In both cases, it agrees with the similar rule for
Haldane chain with appropriate spin number.Comment: 4 pages, some references updated and added, typos corrected, to
appear in Phys. Rev.
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