A Hybrid optimization method for real-time pump scheduling

Session S6-02, Special Session: Evolutionary Computing in Water Resources Planning and Management IILinear, non-linear and dynamic programming, heuristics and evolutionary computation are amongst the techniques which have been applied to obtain solutions to optimal pump-scheduling problems. Most of these either greatly simplify the complex water distribution system or require significant time to solve the problem. The scheduling of pumps is frequently undertaken in near-real time, in order to minimize cost and maximize energy savings. However, this requires a computationally efficient algorithm that can rapidly identify an acceptable solution. In this paper, a hybrid optimization model is presented, coupling Linear Programming and Genetic Algorithms. The resulting hybrid optimization model has demonstrated more rapid convergence with respect to the traditional metaheuristic algorithms, whilst maintaining a good level of reliability

Sediment transport dynamics in the swash zone under large-scale laboratory conditions

A laboratory experiment was carried out to study sediment transport dynamics occurring in the swash zone of a coarse-sandy beach built in a large-scale wave flume. Hydro- and morpho-dynamic as well as sediment transport data were collected using sensors mounted on a scaffold rig deployed in the lower swash zone close to the moving bed. The high resolution of near-bed data permitted quantitative evaluation of suspended and sheet flow contributions to the total sediment transport. Although sheet flow sediment fluxes were higher than suspended fluxes, the vertically integrated suspended sediment load overcame the sheet flow load during uprush and it was on the same order of magnitude during backwash. The observed cumulative sediment transport was generally larger than the morphological changes occurring shoreward of the rig location implying either an underestimation of the offshore sediment transport or an overestimation of the onshore fluxes obtained from concentration and velocity profile data. Low correlations were found between net swash profile changes and runup parameters suggesting that local hydrodynamic parameters provide little or no predictability of accretion and erosion of an upper beach which is near equilibrium. The balance between erosion and deposition induced by individual swash events brought a dynamic equilibrium with small differences between the profiles measured at the start and at the end of the run

Economic viability and greenhouse gas (GHG) budget of the biomethane retrofit of manure-operated biogas plants: A case study from Piedmont, Italy

The management of livestock manures and slurries noticeably improved since the massive introduction of anaerobic digestion (AD) plants in Italy and other European Union (EU) countries. However, these plants heavily rely on incentives, and the recent switch of European biogas policies from electricity to biomethane potentially threatens the economic viability of manure AD. In this study, three retrofit options are analyzed for an installation in Piedmont (NW Italy) that is currently producing 999 kWel through combined heat and power (CHP). The techno-economic feasibility and the greenhouse gas (GHG) budget is analyzed for each solution. Results show that exploiting current incentives on electricity is vital to fund the retrofit of CHP plants to biomethane. Energy crop and electricity prices, the sale price of biomethane certificates after the end of incentives, and biogas productivity are the critical parameters for the economic profitability of manure AD plants, along with the possibility to deliver biomethane directly to the pipeline grid. This study provides insight to the reconversion of manure AD plants, addressing issues that affect hundreds of installations in Italy and other EU countries

Polymeric Prodrug

The presently-disclosed subject matter includes compounds that comprise an initiator and an active agent that is covalently bonded to the initiator through a ring-opening polymerization process, an atom-transfer radical polymerization process, a Michael addition reaction, or a ring-opening metathesis polymerization process. In some embodiments the active agent includes simvastatin. The presently-disclosed subject matter also includes methods for making the compositions and methods for using the compositions to treat tissue wounds

Tuning Properties of Poly(ethylene glycol)-\u3cem\u3eblock\u3c/em\u3e-poly(simvastatin) Copolymers Synthesized via Triazabicyclodecene

Simvastatin was polymerized into copolymers to better control drug loading and release for therapeutic delivery. When using the conventional stannous octoate catalyst in ring-opening polymerization (ROP), reaction temperatures ≥ 200 °C were required, which promoted uncontrollable and undesirable side reactions. Triazabicyclodecene (TBD), a highly reactive guanidine base organocatalyst, was used as an alternative to polymerize simvastatin. Polymerization was achieved at 150 °C using 5 kDa methyl-terminated poly(ethylene glycol) (mPEG) as the initiator. ROP reactions with 2 kDa or 550 Da mPEG initiators were also successful using TBD at 150 °C instead of stannous octoate, which required a higher reaction temperature. Biodegradability of the poly(simvastatin) copolymer in phosphate-buffered saline was also improved, losing twice as much mass than the copolymer synthesized via stannous octoate. The three copolymers exhibited modified rates of simvastatin release, demonstrating tunablity for drug delivery applications

Highly Thiolated Poly (Beta-Amino Ester) Nanoparticles for Acute Redox Applications

Disulfides are used extensively in reversible cross-linking because of the ease of reduction into click-reactive thiols. However, the free-radical scavenging properties upon reduction are often under-considered. The free thiols produced upon reduction of this disulfide material mimic the cellular reducing chemistry (glutathione) that serves as a buffer against acute oxidative stress. A nanoparticle formulation producing biologically relevant concentrations of thiols may not only provide ample chemical conjugation sites, but potentially be useful against severe acute oxidative stress exposure, such as in targeted radioprotection. In this work, we describe the synthesis and characterization of highly thiolated poly (β-amino ester) (PBAE) nanoparticles formed from the reduction of bulk disulfide cross-linked PBAE hydrogels. Degradation-tunable PBAE hydrogels were initially synthesized containing up to 26 wt % cystamine, which were reduced into soluble thiolated oligomers and formulated into nanoparticles upon single emulsion. These thiolated nanoparticles were size-stable in phosphate buffered saline consisting of up to 11.0 ± 1.1 mM (3.7 ± 0.3 mmol thiol/g, n = 3 M ± SD), which is an antioxidant concentration within the order of magnitude of cellular glutathione (1–10 mM)

Subsurface processes generated by bore-driven swash on coarse-grained beaches

Peer reviewedPublisher PD

The current status of advanced environmentanl barrier coatings for ceramic matrix composites at NASA

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Surface integrity in dry and cryogenic machining of AZ31B Mg alloy with varying cutting edge radius tools

Surface integrity of machined products has a critical impact on their functional performance. Magnesium alloys are lightweight materials for transportation industry and are also emerging as a potential material for temporary biomedical implants. However, their unsatisfactory corrosion resistance limits their application to a great extent. Surface integrity factors, such as grain size, crystallographic orientation and residual stresses, were reported to have significant influence on corrosion resistance of AZ31 Mg alloys. In this study, AZ31B Mg discs were orthogonally turned using cutting tools with two edge radii under both dry and cryogenic conditions. The influence of cutting edge radius and cooling method on surface integrity was investigated. Cryogenic machining using a large edge radius tool led to a thicker grain refinement layer, larger compressive residual stresses and stronger intensity of basal texture, which may remarkably enhance the corrosion performance of magnesium alloys.info:eu-repo/semantics/publishedVersio