Numerical modelling of a bromide-polysulphide redox flow battery. Part 2: Evaluation of a utility-scale system

Numerical modelling of redox flow battery (RFB) systems allows the technical and commercial performance of different designs to be predicted without costly lab, pilot and full-scale testing. A numerical model of a redox flow battery was used in conjunction with a simple cost model incorporating capital and operating costs to predict the technical and commercial performance of a 120 MWh/15 MW utility-scale polysulphide-bromine (PSB) storage plant for arbitrage applications. Based on 2006 prices, the system was predicted to make a net loss of 0.45 p kWh⁻¹ at an optimum current density of 500 A m⁻² and an energy efficiency of 64%. The system was predicted to become economic for arbitrage (assuming no further costs were incurred) if the rate constants of both electrolytes could be increased to 10⁻⁵ m s⁻¹, for example by using a suitable (low cost) electrocatalyst. The economic viability was found to be strongly sensitive to the costs of the electrochemical cells and the electrical energy price differential.     

Statistical Modeling of PM10 Sampling Effectiveness Data

A flexible distribution is used to fit experimental particulate-sampling effectiveness data by the linear expression of a logarithmically transformed aerodynamic diameter. This model, originally proposed for application to quantal-assay studies, is useful for judging whether the fit of simpler models, such as the logistic or probit, can be improved. The main practical advantage is that it facilitates accurate computation of expected particulate mass concentrations, as specified in the Code of Federal Regulations regarding performance specifications for PM₁₀ samplers. An unresolved problem is the exceedingly precise estimates of particle diameter corresponding to a sampling effectiveness value that may not reflect the true situation. Comparison of the fit to effectiveness data obtained for two PM₁₀ sampler inlets is presented. This discussion includes use of a statistical technique to construct a confidence limit for the median diameter.     

Effect of Humidity on NPK Fertilizer Drying

ABSTRACT

The drying process within rotary coolers during the manufacture of granular NPK fertilizer plays an important role in the production of fertilizer granules possessing both a low moisture content and low caking propensity. A theory for fertilizer drying has been developed which takes into account the low critical relative humidity of complex fertilizer found at high temperature. The theory proposes that the gradient between the partial vapour pressure of moisture in the air and the vapour pressure moisture adjacent to the surface of the fertilizer granule, is the rate controlling stage in the drying of hot granular fertilizer rather than the internal diffusion of moisture within the particle.     

Quantitative Multi-Inspection-Site Comparison of Probability of Detection for Vibrothermography Nondestructive Evaluation Data

This paper describes the estimation of probability of detection (POD) for a vibrothermography inspection procedure. The results are based on a large scale experiment on specimens with two different kinds of metal containing fatigue cracks. The specimens were tested independently at three inspection sites: Iowa State University (ISU), Pratt and Whitney (PW) and General Electric (GE). Despite the substantially different vibrothermography configurations and experimental measurement responses, the estimated PODs as function of crack length and dynamic stress were similar for all three inspection sites, which make quantitative POD comparisons possible across different inspection sites.     

Australia,uranium and nuclear power

The nuclear debate in Australia is shaped by the nation's substantial base of energy resources, including its large reserves of uranium and recent rises in the market price of uranium. But the debate also echoes Australia's past in the development of programs for nuclear weapons. The proposals include uranium enrichment, the storage of nuclear waste in Australia, and the introduction of nuclear reactors. A national inquiry has been instituted by the government. These developments, stemming from a range of factors, have revived the opposition to uranium mining and nuclear power which has for two decades held a dominant role in Australian politics. The issue of what should be Australia's energy path in a time of climate change is beginning to be examined. The importance of the decisions, whether to be a player in the nuclear club with its attendant multiple hazards, or to play a quite different leadership role in the development and adoption of sustainable energy strategies and technologies, cannot be exaggerated.     

Land Use Planning and Bushfire Risk: CFA Referrals and the February 2009 Victorian Fire Area

The Victoria Planning Provisions (VPPs) include siting and design regulations incorporated into local government planning schemes to mitigate risk in areas prone to bushfires. Introduced in 1997, these provisions were previously called the Wildfire Management Overlay (WMO). Now updated and renamed the Bushfire Management Overlay (BMO), the provision's ongoing development has been informed by fire behaviour and how houses ignite. The aim of the research reported here, conducted following the catastrophic February 2009 Victorian fires, was to review dwelling losses in terms of the WMO's effectiveness. Empirical evidence compares house losses of dwellings referred to the Country Fire Authority (CFA) via the WMO, with overall house losses. The results suggest that proportionately fewer houses referred to the CFA were lost, compared with those not assessed under the WMO. It should be noted that other factors influenced the results, such as the houses assessed under the WMO being generally newer.     

Long-Run Trends in Victorian Housing Affordability and First Transition into Homeownership

Over the past two decades housing pathways have become increasingly differentiated between generations, particularly in advanced societies dominated by owner-occupied tenure systems. Demographic transformations caused by aging and falling fertility rates, along with a more volatile economy and a neo-liberal reorientation of governance have combined to restructure housing conditions. Drawing on empirical research in Japan, this paper illustrates the social origins and impact of generation-based differentiations in housing patterns in that country. It considers the housing experiences of three cohorts: baby-boomers, baby-busters and the ‘lost generation’. The contrast of housing pathways between these generations in Japan illustrates the contemporary dynamics of housing and social processes in homeowner societies.     

Core–periphery dynamics in the Portland, Oregon, region: 1982–2006

The relative strength of positive and negative spillovers of urban development is a long-standing and contested issue in regional and development economics, and the search for spread and backwash effects of development in urban core economies goes back at least 50 years. Using data from IMPLAN and the Bureau of Economic Analysis to develop multiregional input–output models, we developed estimates of core–periphery economic interdependence (sales and purchases of goods and services and commuting of workers between the core and the periphery) of the Portland, Oregon, region for 1982 and 2006. We explored whether the changing flows of sales and purchases, spillovers and commuting between 1982 and 2006 suggested a dominance of spread effects or backwash effects. We found increased commuting between periphery and core, decreased core–periphery transactions, and smaller core-to-periphery spillovers and periphery-to-core spillovers in both goods and services. Our findings do not point to a clear dominance of spread or backwash effects. Results showing smaller core-to-periphery and periphery-to-core multipliers/spillovers suggest that spread effects related to trade in goods and services weakened between 1982 and 2006. Our findings of increased commuting are consistent with enhanced spread effects in labor markets.     

A modification of broyden's method for the solution of sparse systems—with application to distillation problems described by nonideal thermodynamic functions

An algorithm that permits Broyden's method to be used for the solution of large systems of algebraic equations with sparse Jacobians is presented. The new procedure is compared to Schubert's modification of Broyden's method and to the Newton-Raphson method by solving an extractive distillation problem. It is demonstrated that the new procedure is competitive with Schubert's method when it is necessary to evaluate Jacobian matrices numerically.     

Polymer modification and synthesis using sulphenyl derivatives: 9. Addition of alkylsulphenyl chlorides to cis-1, 4-polybutadiene

Methanesulphenyl chloride and n-butanesulphenyl chloride add readily across the double bonds in cis-1,4-polybutadiene. The addition is highly regioselective so that long sequences of saturated units are formed. The products are very unstable, evolving hydrogen chloride on standing, but can be stabilized by replacing the labile chlorine atom with other nucleophiles in a phase transfer catalysed reaction.