Use of the Split-Film Sensor to Measure Turbulence in Water near a Wall

Because of its small size and unique design, the 0.15-mm diameter split-film sensor has many significant advantages over the conventional X-configuration hot-film sensor and the yaw-wire technique for measuring turbulence near a wall. Calibration of the split- film sensor indicates that the magnitude and yaw angle of the instantaneous velocity vector is dependent only on the sum and ratio of the sensor outputs, respectively. Results of limited measurements of the longitudinal and vertical turbulence intensities and Reynolds stress for hydraulically smooth, free surface flows are presented. Digital time series of the split-film outputs revealed the following information: (1) the split-film sensor longitudinal and vertical turbulence intensities and Reynolds stress compares favorably with previous studies; (2) the split-film sensor can be used as an instantaneous velocity vector transducer; (3) the split-film sensor is capable of making two-dimensional turbulence measurements in water to within five probe diameters of the wall. Calibration and experimental results indicate that the split-film sensor may be useful in improved spatial definition of the turbulent structure in wall shear flows

A novel profluorescent dinitroxide for imaging polypropylene degradation

Free-radical processes underpin the thermo-oxidative degradation of polyolefins. Thus, to extend the lifetime of these polymers, stabilizers are generally added during processing to scavenge the free radicals formed as the polymer degrades. Nitroxide radical precursors, such as hindered amine stabilizers (HAS),1,2 are common polypropylene additives as the nitroxide moiety is a potent scavenger of polymer alkyl radicals (R¥). Oxidation of HAS by radicals formed during polypropylene degradation yields nitroxide radicals (RRNO¥), which rapidly trap the polymer degradation species to produce alkoxyamines, thus retarding oxidative polymer degradation. This increase in polymer stability is demonstrated by a lengthening of the “induction period” of the polymer (the time prior to a sharp rise in the oxidation of the polymer). Instrumental techniques such as chemiluminescence or infrared spectroscopy are somewhat limited in detecting changes in the polymer during the initial stages of degradation. Therefore, other methods for observing polymer degradation have been sought as the useful life of a polymer does not extend far beyond its “induction period

Multi-Objective Optimization of Pumping Operations from Alternative Water Sources

Water supply and distribution systems are an integral part of our society and can incur significant costs in their construction and operation. Many different optimization techniques have been applied to both the design and operation of traditional potable systems, which generally receive water from natural water bodies. As climate change and increasing populations prompt concerns of water security, in addition to natural harvested water supplies, alternative sources such as harvested stormwater, recycled wastewater and desalination are becoming more commonly used for both potable and nonpotable supply. These systems have not been researched as extensively, particularly their operation. This thesis examines the optimisation of pumping operations in water supply and distribution systems that can include conventional potable systems as well as systems that use alternative water sources. The major contributions of this research are presented in three publications. Firstly, a single-objective optimisation model was applied to potable water distribution systems, both hypothetical and real, for different types of pump operating regimes using the EPANET toolkit to alter rule-based controls. While minimizing pump energy costs was the primary objective, minimization of greenhouse gas emissions was also explored, including the variation of greenhouse gas emission factors for different electrical energy sources. Time-based scheduling operating strategies were found to perform better than the other operating regimes, and significant cost savings were achieved for the real-life system compared to its current operation. In the second paper, a framework for the optimization of water supply and distribution systems that use alternative water sources is presented, along with a detailed discussion of the components and key variables. The framework connects the potential decision variables, both design and operational, the physical components of the water system to be modelled, the simulation of each potential system configuration and evaluation against objectives and constraints, and relevant policies from regulating bodies. These all exist within an optimization algorithm structure, and sensitivity analysis of uncertain variables is also discussed. Two case study systems are used to illustrate how the framework would be applied to minimize the cost of water system operations. The final paper applies multi-objective optimisation techniques to a harvested stormwater case study system and also covers an extensive sensitivity analysis of the inputs to the system. This system has distinct winter (harvesting) and summer (irrigation) operational seasons; for the winter operation, operating rules were optimized to minimize the cost of pumping into an aquifer and to maximize the volume harvested, considering restrictions on the aquifer injection rate and pressure; during summer, irrigation scheduling was optimized to minimize pumping costs, considering the requirements for irrigation rates and amounts at various public parks and green area reserves. Results from both the optimisation and sensitivity analysis found operational cost savings if new pumps are installed, wider trigger levels are used, and certain reserves are irrigated together. This research has produced significant overall contributions to the body of knowledge. Methodologies have been developed for optimisation of potable and alternative water sources systems, highlighting important considerations and generalizable results. For three real-life case study systems, operating strategies and infrastructure changes have been suggested to provide significant savings in the cost of pumping operations.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 201

Stochastic Co-design of Storage and Control for Water Distribution Systems

Water distribution systems (WDSs) are typically designed with a conservative estimate of the ability of a control system to utilize the available infrastructure. The controller is subsequently designed and tuned based on the designed water distribution system. This sequential approach may lead to conservativeness in both design and control steps, impacting both operational efficiency and economic costs. In this work, we consider simultaneously designing infrastructure and developing a control strategy, the co-design problem, to improve the overall system efficiency. However, implementing a co-design problem for water distribution systems is a challenging task given the presence of stochastic variables (e.g. water demands and electricity prices). In this work, we propose a tractable stochastic co-design method to design the best tank size and optimal control parameters for WDS, where the expected operating costs are established based on Markov chain theory. We also give a theoretical result that investigates the average long-run co-design cost converging to the expected cost with probability 1. Furthermore, the method can also be applied to an existing WDS to improve operation of the system. We demonstrate the proposed co-design method on three examples and a real-world case study in South Australia

The e-Framework

The e-Framework is an initiative by Australia's Department of Education, Science and Training (DEST), the U.K's Joint Information Systems Committee (JISC), New Zealand’s Ministry of Education (MoE), and the Netherlands SURF Foundation to produce an evolving and sustainable, open standards based, service oriented technical framework to support the education and research communities. The primary goal of the e-Framework is to facilitate technical interoperability within and across education and research through improved strategic planning and implementation processes. The e-Framework supports a service oriented approach to developing and delivering education, research and management information systems. Such an approach maximises the flexibility and cost effectiveness with which systems can be deployed, both in an institutional context, nationally and internationally. The e-Framework allows the communities to document its requirements and processes in a coherent way, and to use these to derive a set of interoperable network services. By documenting requirements, processes, services, protocol bindings, schemas and standards in the form of 'service usage models' members of the community are better able to collaborate on the development of service components that meet their needs (both within the community and with commercial and other international partners). This paper will outline some of the practical ways in which communities have engaged with the e-Framework and the challenges faced in terms of creating a sustainable and flexible resource base

Wavelength-Orthogonal Stiffening of Hydrogel Networks with Visible Light

Herein, we introduce the wavelength-orthogonal crosslinking of hydrogel networks using two red-shifted chromophores, i.e. acrylpyerene (AP, λ$_{activation}$=410–490 nm) and styrylpyrido[2,3-b]pyrazine (SPP, λ$_{activation}$=400–550 nm), able to undergo [2+2] photocycloaddition in the visible-light regime. The photoreactivity of the SPP moiety is pH-dependent, whereby an acidic environment inhibits the cycloaddition. By employing a spiropyran-based photoacid generator with suitable absorption wavelength, we are able to restrict the activation wavelength of the SPP moiety to the green light region (λ$_{activation}$=520–550 nm), enabling wavelength-orthogonal activation of the AP group. Our wavelength-orthogonal photochemical system was successfully applied in the design of hydrogels whose stiffness can be tuned independently by either green or blue light