Simulating the effects of climate change,economic and urban planning scenarios on urban runoff patterns of a metropolitan region

Urban development and climate change are expected to have significant effects on urban stormwater runoff. In this study, the Dynamic Urban Water Simulation Model (DUWSiM) is applied to Dublin, Ireland, to explore urban runoff patterns under varying urban growth and climate scenarios. Results show that annual urban runoff could decrease by 3.0% from climate change and monthly runoff could increase by 30% in winter and decrease by 28% in summer. Results also indicate that urban growth could increase annual runoff by up to 15%. The combined effect of climatic and land-use change generated runoff may potentially increase annual totals from between 2.9% to 21%. Monthly changes in runoff totals could increase by up to 57%. Accommodating these variations in runoff between the scenarios, flexible decentralised systems such as green roofs and pervious pavements, have a vital role in increasing the adaptability and long term sustainability of water infrastructure.     

Evaluation of the corrosion resistance of anodized aluminum 6061 using electrochemical impedance spectroscopy (EIS)

The corrosion resistance of anodized Al 6061 produced by two different anodizing and sealing processes was evaluated using electrochemical impedance spectroscopy (EIS). The scanning electron microscope (SEM) was employed to determine the surface structure and the thickness of the anodized layers. The EIS data revealed that there was very little change of the properties of the anodized layers for samples that were hard anodized in a mixed acid solution and sealed in hot water over a 365 day exposure period in a 3.5 wt% NaCl solution. The specific admittance A_s and the breakpoint frequency f_b remained constant with exposure time confirming that the hard anodizing process used in this study was very effective in providing excellent corrosion resistance of anodized Al 6061 over extended exposure periods. Some minor degradation of the protective properties of the anodized layers was observed for samples that were hard anodized in H₂SO₄ and exposed to the NaCl solution for 14 days.     

Practical phase identification by convergent beam electron diffraction

The purpose of this article is to present a practical guide to the identification of phases in the analytical electron microscope with the aid of convergent beam electron diffraction. There is included a step-by-step approach to phase analysis, from the possible choices of the form of the specimen through how to explore reciprocal space in order to perform a full phase identification, either by symmetry analysis or by simple comparison of a pattern observed in the microscope with a previously recorded pattern (fingerprinting). There is a strong emphasis on practical hints and useful shortcuts.     

Surface Films and Soluble Degradation Products Formed in a PFPAE Fluid and Their Implications to the Wear of Steel

The soluble degradation products were generated in a linear perfluoropolyalkylether (PFPAE) fluid in boundary lubrication. Perfluoropolyalkylether carboxylic acid species were found in the residual fluids from the sliding tests by vibration spectroscopy. Surface-bound organic and inorganic reaction products were identified by vibration microspectroscopy with a grazing angle objective attachment and X-ray photoelectron spectroscopy (XPS), respectively. Inorganic surface films were found to be composed primarily of FeF₃. A monodentate perfluorocarboxylate surface species was found on the sliding surfaces in 50° and 100°C tests but not found in 150°C tests. The higher friction and wear in 150°C tests as compared to 50° and 100°C tests were attributed to the absence of the perfluorocarboxylate species over the sliding surfaces at high temperatures.     

The busbar system for Wendelstein 7-X prepared for assembly and operational loads

Forschungszentrum Jülich has taken over the design, manufacturing and assembly of the superconducting busbar system for the stellarator Wendelstein 7-X. This includes the busbars itself, the support structure consisting of supports and clamps, and the joints for electrical and hydraulic connection of the busbars and coil terminals. Apart from providing the required electrical connection scheme, the busbar system has to be designed for relevant electrical and mechanical loads. Numerous interfaces and geometric boundary conditions define the confined space to accommodate the busbars and their support elements. This article describes how the individual challenges to engineering have been met in the course of the project. This includes design concepts and the method for iterative design of supports with respect to the individual load distribution caused by the supports itself.     

Low-temperature mechanical properties of superconducting radio frequency cavity materials

Low-temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30-40 MPa √m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.     

Disproportionation of Pu(IV): A reassessment of kinetic and equilibrium properties

Kinetic results for disproportionation of Pu(VI) and reaction of Pu(III) with Pu(VI) show that rates of in HNO₃ and HClO₄ solutions are described by trimolecular rate laws consistent with involvement of trimeric hydroxo complexes as reactive intermediates in the slow mechanistic steps. Product ratios and modeling of concentration-time curves reveal that Pu(V) is formed by reduction of Pu(VI) product in a secondary reaction. Results do not support the accepted interpretation that attributes reversible reaction and Pu(V) formation to a two-step bimolecular process. Secondary redox reactions driven by disproportionation of Pu(VI) prevent attainment of equilibrium in 1 M H⁺ and determine long-term redox chemistry. The equilibrium constant (0.00051) defined by forward and reverse rate constants for 1 M HClO₄ agrees with that (0.00049) derived from concentration data for 1 M HNO₃, but not with prior results. Disagreement of these values with that calculated from thermodynamic data suggests that steady-state Pu concentrations are controlled by kinetics. Possible pathways of secondary reactions are identified and a mechanism for reversible oxygenation of plutonium ions is described.     

Symbolic pixel labeling for curvilinear feature detection

This paper describes a method of detecting thin curvilinear features in an image based on a detailed analysis of the local gray level patterns at each pixel. This allows operations such as thinning and gap filling to be based on more accurate information.     

Creation of small kinetic models for CFD applications: a meta-heuristic approach

This paper updates a method for generating small, accurate kinetic models for applications in computational fluid dynamics programs. This particular method first uses a time-integrated flux-based algorithm to generate the smallest possible skeletal model based on the detailed kinetic model. Then, it uses a multi-stage optimization process in which multiple runs of a genetic algorithm are used to optimize the rate constant parameters of the retained reactions. This optimization technique provides the user with the flexibility needed to balance the fidelity of the model with their time constraints. The updated method was applied to the reduction of a methane-air model under conditions meant to approximate the end of a compression stroke of an internal combustion engine. When compared to previous techniques, the results showed that this method could produce a more accurate model in considerably less time. The best model obtained in this study resulted in relative errors ranging from 0.22 to 1.14% on all six optimization targets. This reduced model was also able to adequately predict optimization targets for certain operating conditions, which were not included in the optimization process.