Response of inertinites from some Australian coals to non-catalytic hydrogenation in tetralin

Inertinite concentrates from three Australian bituminous coals were hydrogenated at various temperatures ranging from 350 to 475 °C in the presence of tetralin without any added catalyst. Both conversion yields and microscopic observations of the benzene-extracted hydrogenation residues have revealed that the hydrogenation of the inertinite macerals becomes significant only > 400 °C, whereas the dissolution-hydrogenation of the accompanying vitrinite macerals occurs mainly between 350 and 400 °C. The major reaction pathway for the inertinite particles in the hydrogenation process appears to be one of initial mild carbonization followed by hydrogenation. A simplified reaction scheme is proposed which describes the reaction pathway involved in the hydrogenation of inertinite.     

Structural stability of single-layered LaNi4.25Al0.75 film and its electrochemical hydrogen-storage properties

AB5-based hydrogen storage thin fdms （LaNi4.25Al0.75）, deposited on Cu substrate by dc magnetron sputtering were investigated in this study. X-ray diffraction （XRD） revealed that the microstructure of the layer was in crystal form. SEM and AFM analyses proved that the film appeared to be rather rough with numerous randomly sized pores of approximately 15-40 in nm diameter. Structural stability of the film was examined by the combined analyses of DSC, XRD, and SEM, which indicated that this film maintained its structural stability below 500 K or so, and a network structure was observed on the film after being heated at 700 K for 30 min. Electrochemical hydrogen-storage properties of the films were investigated by simulated battery tests. It was found that single-layered LaNi4.25A10.75 film exhibited electrochemical hydrogen-storage properties similar to typical AB5 alloys in bulk, and the maximum discharge capacity of the film was about 220 mAh/g. After 20 charge/discharge cycles, small needle-shaped aluminium oxide was formed on some fractions of the film surface.     

A modified θ projection model for constant load creep curves-II. Application of creep life prediction

To minimize the deviation of the predicted creep curves obtained under constant load conditions by the original θ projection model, a new modified version that can be expressed by $\epsilon ={\theta }_1\left(1-e^{-{\theta }_{2}t}\right)+{\theta }_3\left(e^{{\theta }_4{e}^{{\theta }_5\epsilon }t}-1\right)$, was derived and experimentally validated in our last study. In the present study, the predictive capability of the modified θ projection model was investigated by comparing the simulated and experimentally determined creep curves of K465 and DZ125 superalloys over a range of temperatures and stresses. Furthermore, the linear relationship between creep temperature and initial stress was extended to the 5-parameter model. The results indicated that the modified model could be used as a creep life prediction method, as it described the creep curve shape and resulted in predictions that fall within a specified error interval. Meanwhile, this modified model provides a more accurate way of describing creep curves under constant load conditions. The limitations and future direction of the modified model were also discussed. In addition, this modified θ projection model shows great potential for the evaluation and assessment of the service safety of structural materials used in components governed by creep deformation.     

Microstructural Stability and Hot Deformation of γ–γ′–δ Ni-Base Superalloys

Nickel-base superalloys exhibit excellent high-temperature mechanical and physical properties and remain the first choice for structural components in advanced gas turbine engines for the aerospace propulsion and power generation applications. In response to the increasing demand for more efficient solutions and tighter requirements linked to gas turbine technologies, the properties of nickel-base superalloys can be improved by modification of their thermo-mechanical and/or compositional attributes. Recent investigations have revealed the potential use of ternary eutectic γ–γ′–δ Ni-base superalloys in advanced gas turbines due to high temperature mechanical properties that are comparable to state-of-the-art polycrystalline Ni-base superalloys. With properties largely dependent on microstructural strengthening mechanisms, both the composition and thermo-mechanical processing parameters of this novel class of alloys need to be optimized concurrently. The hot deformation characteristics of four γ–γ′–δ Ni-base superalloys with varying levels of Nb were evaluated at temperatures and strain rates between 1353 K and 1433 K (1080 °C and 1160 °C) and 0.01 to 0.001/s, respectively. Evidence of dislocation-based plasticity was observed following deformation at low temperatures and high strain rates, while high temperatures and low strain rates promoted superplasticity in these alloys. The extent of the microstructural changes and the magnitude of the cavitation damage which occurred during deformation was found to vary as a function of the alloy composition.     

Temburong Bridge,Brunei – Design of two cable stayed bridges

The Temburong Bridge Project is a 30 km long dual two‐lane highway crossing over the Brunei Bay. It will connect the relatively isolated Brunei district of Temburong to the other three Brunei districts. The main objective of the project is to stimulate economic growth in the Temburong region by connecting it to the country's airport and ports. The alignment crosses two navigation channels resulting in the need for two cable stayed bridges – the Brunei Channel Bridge (145 m main span) and the Eastern Channel Bridge (260 m main span). The design of these cable stayed bridges is one of the first applications of the Eurocode to a fully concrete cable stayed bridge. Both cable stayed bridges draw on strong Islamic architectural influences from the region to form a tower shape that is unique and instantly recognisable. Temburong Brücke, Brunei – Entwurf von zwei Schrägkabelbrücken Die Temburong Brücke ist eine 30 km lange Verbindung über die Brunei Bucht mit zwei Richtungsfahrbahnen mit je zwei Fahrstreifen. Sie wird den relativ isolierten Distrikt Temburong mit den anderen drei Distrikten Bruneis verbinden. Hauptanliegen des Projekts ist die Stimulierung von ökonomischem Wachstum in der Temburong Region, indem sie an den Flughafen und Seehafen des Landes angebunden wird. Die Trassierung erfordert die Überquerung zweier Schiffahrtsrouten. Dies wird mit der Anordnung zweier Schrägkabelbrücken ermöglicht, der Brunei Channel Brücke (145 m Hauptspannweite) und der Eastern Channel Brücke (260 m Hauptspannweite). Die Bemessung der beiden Brücken stellt eine der ersten Anwendungen des Eurocode auf Schrägkabelbrücken mit Betonüberbau dar. Optisch sind die beiden Brücken geprägt von der islamischen Architektur der Umgebung, die Pylonform ist ein besonderes Erkennungsmerkmal der Brücken.     

Civil engineers' managerial roles and needs: report of survey

Attitudes to the monetary risks associated with business decisions are thought to vary in response to at least three identifiable stimuli: the amount of money involved, background economic conditions and the framing of the decision. This paper reports a study of peoples' attitude to risk before and after a real turning point in the real business cycle. This work sheds light on the extent to which (i) risk attitudes remain robust when economic conditions change, (ii) risk attitude is influenced by whether the choice problem is concerned with losses or with gains, and (iii) risk attitude may be subordinated to some other dominating objective.     

Copper‐Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl‐N‐methylimidazole Michael Acceptors: Scope,Limitations and Iterative Reactions

An efficient copper‐catalyzed enantioselective conjugate addition of dimethylzinc to unsaturated 2‐acyl‐N‐methylimidazoles has been achieved using a chiral bidentate hydroxyalkyl‐NHC ligand. The reactions proceed with excellent regioselectivity (1,4 vs. 1,6 and 1,8) in extended conjugated systems to afford the 1,4‐adducts in high enantioselectivities. This regioselectivity could be ascertained by DFT studies highlighting the crucial role of the imidazole ring. Thanks to the development of efficient protocols to regenerate the unsaturated 2‐acyl‐N‐methylimidazole moiety, an iterative process has been developed ultimately leading to 3,5,7 all‐syn or anti‐anti polydeoxypropionate stereodiads.

     

The Rising Costs of Floods: Examining the Impact of Planning and Development Decisions on Property Damage in Florida

The rising economic cost of floods in the United States cannot be explained solely by monetary inflation or growth in coastal populations. Damaging flood events are also influenced by the way society plans for and physically develops its communities, influencing where structures and impervious surfaces are concentrated and how hydrological systems are altered. We analyze 383 nonhurricane flood events in Florida counties between 1997 and 2001 to isolate how planning decisions and their effects on the built environment affect property damage caused by floods. Our results suggest that alteration of naturally occurring wetlands significantly increases the property damage caused by floods, all else equal. Also, nonstructural methods such as the Federal Emergency Management Agency's Community Rating System, while providing inexpensive means of reducing property damage directly, may also indirectly encourage more development in hazardous areas.     

Lightweight and provably secure user authentication with anonymity for the global mobility network

Seamless roaming in the global mobility network (GLOMONET) is highly desirable for mobile users, although their proper authentication is challenging. This is because not only are wireless networks susceptible to attacks, but also mobile terminals have limited computational power. Recently, some authentication schemes with anonymity for the GLOMONET have been proposed. This paper shows some security weaknesses in those schemes. Furthermore, a lightweight and provably secure user authentication scheme with anonymity for the GLOMONET is proposed. It uses only symmetric cryptographic and hash operation primitives for secure authentication. Besides, it takes only four message exchanges among the user, foreign agent and home agent. We also demonstrate that this protocol enjoys important security attributes including prevention of various attacks, single registration, user anonymity, user friendly, no password/verifier table, and use of one‐time session key between mobile user and foreign agent. The security properties of the proposed protocol are formally validated by a model checking tool called AVISPA. Furthermore, as one of the new features in our protocol, it can defend smart card security breaches. Copyright © 2010 John Wiley & Sons, Ltd.