214,054 research outputs found
Ellen (Ella) Stack
No full textDate:1941Ella Stack and her family moved to Darwin in 1961. She was first employed for a few weeks mid-1961 by a local GP and then in 1962, Ella took over as long-term locum. She was one of two private practitioners in Darwin. Cyclone Tracy hit Darwin in 1974. Instead of evacuating, she chose to stay and provide medical support and to help with the reconstruction of the city. Dr Stack became a member of the Darwin Reconstruction Commission that enacted a new building code to prevent similar devastation in the future.
In May 1975 she was elected the first woman Mayor of Darwin and with self-government, became Lord Mayor of Darwin in 1979. After stepping down as Lord Mayor in 1980, she completed her Masters of Public Health, joining the Department of Health as the first Assistant Secretary of the Division of Aboriginal Health. It was the first Division devoted entirely to the health of Aboriginals. Later she became Secretary of the Department of Health of the Northern Territory.
Source: Northern Territory dictionary of biography. Darwin : Charles Darwin University Press, 2008.DoctorMayorLord Mayo
Design improvement of circular molten carbonate fuel cell stack through CFD Analysis
No full textMolten carbonate fuel cell (MCFC) is a promising technology for distributed power generation. The core of an MCFC power generation unit is the stack, where various fuel cells are connected together in series and parallel in order to obtain the desired voltage and power. Stack geometry and configuration are major engineering topics, as inhomogeneous temperature or mass fractions cause inefficient performances of the fuel cells, as efficiency and power smaller than the expected and shorter lifetime. A detailed model is a useful tool to improve stack performances, through design improvements. In this paper, a 3D model of a stack composed of 15 circular MCFC, considering heat, mass and current transfer as well as chemical and electrochemical reactions is presented. The model validation is conducted using some preliminary experimental data obtained for an MCFC stack developed in the Fabbricazioni Nucleari laboratories. These results are examined in order to improve the stack configuration. It is shown that power density may be increased of about 20% through double side feeding. In addition, the average temperature gradients in the axial direction are reduced of more than 70%. Significant reductions in the temperature gradients, especially in transversal direction, can be achieved by adjusting the mass flow rate of cathodic gas supplied to the various cell
Numerical computation for parallel plate thermoacoustic heat exchangers in standing wave oscillatory flow
No full textA simplified computational method for studying the heat transfer characteristics of parallel plate thermoacoustic heat exchangers is presented. The model integrates the thermoacoustic equations of the standard linear theory into an energy balance-based numerical calculus scheme. Details of the time-averaged temperature and heat flux density distributions within a representative domain of the heat exchangers
and adjoining stack are given. The effect of operation conditions and geometrical parameters on the heat exchanger performance is investigated and main conclusions relevant for HX design are drawn as far as fin length, fin spacing, blockage ratio, gas and secondary fluid-side heat transfer coefficients are concerned. Most relevant is that
the fin length and spacing affect in conjunction the heat exchanger behaviour and have to be simultaneously optimized to minimize thermal losses localized at the HX-stack
junctions. Model predictions fit experimental data found in literature within 36% and 49% respectively at moderate and high acoustic Reynolds numbers
On Multi-stack Visibly Pushdown Languages
No full textWe contribute to the theory of formal languages of visibly multistack pushdown automata (MVPA). First, we show closure under the main operations and decidability of the main decision problems for the class of MVPA restricted to computations where a symbol can be popped out of a stack S only if it was pushed within the last k contexts of S, for a given k (in a context only one stack can be pushed or popped). In particular, this class turns out to be determinizable. Second, we show the closure under complement of the class of languages accepted by ordered MVPA (where the limitation is that a stack can be popped only if all the lower indexed stacks are empty). This gains decidability of universality, inclusion and equivalence for this class. As a further contribution, we compare the classes of languages accepted by different models of MVPA
Adaptive Selbstlernaufgaben mit STACK
No full text<p>Die Beschäftigung mit Übungsaufgaben ist das wichtigste Lerninstrument für die Mathematik. An der Ruhr-Universität Bochum werden fächerübergreifend Studierenden zur eigenverantwortlichen Vor- und Nachbereitung digitale Mathematikaufgaben in einem eLearning-Kurs zum Selbststudium angeboten. Diese nutzen intensiv die Randomisierungs- und die differenzierten Feedback-Möglichkeiten des Aufgabentyps STACK. Erste Aufgaben wurden nun durch adaptive Aufgabenstellungen, die auch Zwischenschritte ermöglichen, ergänzt.</p>
Algorithmic Debugging of Real-World Haskell Programs: Deriving Dependencies from the Cost Centre Stack
No full textExisting algorithmic debuggers for Haskell require a transformation of all modules in a program, even libraries that the user does not want to debug and which may use language features not supported by the debugger. This is a pity, because a promising ap- proach to debugging is therefore not applicable to many real-world programs. We use the cost centre stack from the Glasgow Haskell Compiler profiling environment together with runtime value observations as provided by the Haskell Object Observation Debugger (HOOD) to collect enough information for algorithmic debugging. Program annotations are in suspected modules only. With this technique algorithmic debugging is applicable to a much larger set of Haskell programs. This demonstrates that for functional languages in general a simple stack trace extension is useful to support tasks such as profiling and debugging
DESIGN & DEVELOPMENT OF PLANAR SOLID OXIDE FUEL CELL STACK
No full textIn the present work, planar anode-supported Solid Oxide Fuel Cell short-stacks have been designed, assembled, tested and characterized. The design of the stacks and its components (frame, housing, interconnect, compressive and bonded seals) required a great attention to the materials properties (i.e. thermal expansion coefficient compatibility, durability, strength and oxidation resistance, conductivity and so on), as well as to the fluid-dynamic analysis focused on flow field and gas distribution. Then, a careful analysis was done based on a multidisciplinary approach to select the stack components materials, geometries, and dimensions; in order to assure a high performing stack at elevated temperatures with cost reduction of materials, parts manufacturing and assembly procedure. The materials selected were: Crofer®22APU for the interconnect and the frame; AISI 316L for bolts and housing; Thermiculite® 866 for the compressive seal placed between the frame and the interconnect plate; Flexible Mica Paper for the compressive seal positioned between the interconnect endplate and the housing; SiO2-CaO-Al2O3-Na2O glass-ceramic sealant for the bonded seal to join the frame with the cell. On the other hand, the stack assembly was focused on the implementation of innovative and simple procedures, which allowed power capacity scale-up in accordance to power requirements. In this work, two different stack configurations were produced: with one cell (for initial testing of the materials and fluid-dynamic selected solutions) and with three cells. It must be mentioned that all developed stacks in this research were assembled with commercial cells "ASC3" from H.C. Starck. Also, calculations at ambient temperature and 800°C were done in the stack compression system to determine the proper tightening torque to be applied: this value was 50N. Although this calculation took into consideration the loss of tightening torque at high temperatures, some marks were found in housing and micas during the stack inspection after disassembly. These marks are a clear indicator of gas leakage. Additionally, a study was carried out related to the effect of the protective Mn1.5Co1.5O4 coating deposited on interconnect surface to prevent the cathode Cr poisoning. This experiment was executed in the stack of one cell configuration. No voltage degradation was observed during the galvanostatic experiment of 360 h at 800°
Fuel cell stack assembly
No full textAn improved proton exchange membrane fuel cell assembly and fuel cell stack assembly are provided for the economical and efficient production of electricity. The present invention comprises improved flow fields and reactant supply systems, which provide improved and more efficient mass transport of the reactants in the fuel cell and the fuel cell stack assembly. The improved flow fields comprise three-dimensional open-cell foamed metals that are preferably plated with gold. The improved reactant supply system comprises an improved distribution frame to house fuel cells wherein the reactants are directly connected to the improved flow fields.U
Divided we stand: Parallel distributed stack memory management
No full textWe present an overview of the stack-based memory management techniques that we used in our non-deterministic and-parallel Prolog systems: &-Prolog and DASWAM. We believe that the problems associated with non-deterministic and-parallel systems are more general than those encountered in or-parallel and deterministic and-parallel systems, which can be seen as subsets of this more general case. We develop on the previously proposed "marker scheme", lifting some of the restrictions associated with the selection of goals while keeping (virtual) memory consumption down. We also review some of the other problems associated with the stack-based management scheme, such as handling of forward and backward execution, cut, and roll-backs
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